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Operational residual risk assessment for

the Salisbury stormwater ASTR project

Declan Page, Joanne Vanderzalm, Karen Barry, Kerry Levett, Sarah Kremer, Maria Neus Ayuso-Gabella, Peter Dillon, Simon Toze, Jatinder Sidhu, Mark Shackleton, Mark Purdie and Rudi Regel

Water for a Healthy Country Flagship Report

April 2009

Water for a Healthy Country Flagship Report series ISSN: 1835-095X

Australia is founding its future on science and innovation. Its national science agency, CSIRO, is a

powerhouse of ideas, technologies and skills.

CSIRO initiated the National Research Flagships to address Australia’s major research challenges

and opportunities. They apply large scale, long term, multidisciplinary science and aim for widespread

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agencies and industry.

The Water for a Healthy Country Flagship aims to achieve a tenfold increase in the economic, social

and environmental benefits from water by 2025. The work contained in this report is a collaboration

between CSIRO and City of Salisbury, United Water, SA Water Corporation and the SA Department of

Water, Land and Biodiversity Conservation (DWLBC).

For more information about Water for a Healthy Country Flagship or the National Research Flagship

Initiative visit www.csiro.au/org/HealthyCountry.html

Citation: Page, D. et al., 2009. Operational residual risk assessment for the Salisbury stormwater

ASTR project. CSIRO: Water for a Healthy Country National Research Flagship

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Cover Photograph:

Description: ASTR well field at Parafield Gardens, South Australia.

Photographer: Kerry Levett

© 2009 CSIRO

Operational residual risk assessment for the Salisbury stormwater ASTR project Page iii

CONTENTS

Acknowledgements ..................................................................................................vii

Executive Summary.................................................................................................viii

1. Introduction........................................................................................................1

1.1. Risk assessment stages ........................................................................................... 1

2. ASTR system configuration..............................................................................4

3. System operation and monitoring 2006-2009 ..................................................7

3.1. Rainfall and quantities captured by the Parafield stormwater harvesting system 2006-2008 .......................................................................................................................... 7

3.2. ASTR well system quantities injected and extracted 2006-2009 ............................. 7

3.3. Water quality monitoring in Parafield stormwater harvesting system 2006-2008 .. 10

3.4. Assessment of the Parafield stormwater harvesting system treatment performance11

3.5. Groundwater water quality monitoring in ASTR system 2006-2009....................... 14

3.6. Assessment of aquifer treatment ............................................................................ 14

3.7. Sampling and analysis summary ............................................................................ 15

4. Hazards in the stormwater harvesting system ..............................................16

4.1. Pathogen numbers in the source water .................................................................. 16

4.2. Inorganic chemicals in the source water................................................................. 17

4.3. Salinity of the source water..................................................................................... 17

4.4. Nutrients in the source water .................................................................................. 17

4.5. Organic chemicals in the source water................................................................... 18

4.6. Turbidity in the source water................................................................................... 18

5. Hazards in the aquifer system ........................................................................19

5.1. Pathogens in the groundwater................................................................................ 19

5.2. Inorganic chemicals in the groundwater ................................................................. 19

5.3. Salinity of the groundwater ..................................................................................... 20

5.4. Nutrients in the groundwater................................................................................... 21

5.5. Organic chemicals in the groundwater ................................................................... 21

5.6. Turbidity in the groundwater ................................................................................... 22

6. Risk assessment..............................................................................................23

6.1. Pathogens............................................................................................................... 23

6.2. Inorganic chemicals ................................................................................................ 24

6.3. Salinity / sodicity ..................................................................................................... 25

6.4. Nutrients.................................................................................................................. 26

6.5. Organic chemicals .................................................................................................. 27

6.6. Turbidity / particulates............................................................................................. 28

6.7. Radionuclides ......................................................................................................... 29

6.8. Pressure, flow rates, volumes and groundwater levels .......................................... 29

6.9. Contaminant migration through preferential flow paths .......................................... 30

6.10. Aquifer dissolution and stability .............................................................................. 31

6.11. Aquifer and groundwater dependent ecosystems .................................................. 31

6.12. Energy and greenhouse gasses ............................................................................. 32

6.13. Risk assessment summary..................................................................................... 32

7. Discussion .......................................................................................................35

Operational residual risk assessment for the Salisbury stormwater ASTR project Page iv

7.1. Pathogen risks ........................................................................................................ 35

7.2. Inorganic chemical risks.......................................................................................... 35

7.3. Organic chemical risks............................................................................................ 36

7.4. Turbidity / particulate risks ...................................................................................... 36

8. Revised water quality sampling for continuous improvements of the risk assessment and management of ASTR .........................................................37

8.1. Baseline monitoring ................................................................................................ 37

8.2. Validation monitoring .............................................................................................. 38

8.3. Operational monitoring............................................................................................ 38

8.4. Verification monitoring ............................................................................................ 39

9. Conclusions and recommendations ..............................................................40

References ................................................................................................................41

Appendix 1 Reedbed water quality data summary 2006-2008 ...............................44

Appendix 2 Groundwater quality data summary 2006-2008 ..................................53

Appendix 3 List of organic chemicals analysed.....................................................59

Appendix 4 Summary of revised monitoring suite.................................................63

Appendix 5 Revised quantitative microbial risk assessment................................64

QMRA Methodology.......................................................................................................... 64

Hazard Identification.............................................................................................................64

Dose-response .....................................................................................................................64

Exposure assessment ..........................................................................................................65

Risk Characterisation ...........................................................................................................65

QMRA Simulation settings....................................................................................................67

QMRA Results .................................................................................................................. 67

QMRA Sensitivity Analysis................................................................................................ 68

Appendix 6 Hydrogeochemical evaluation .............................................................70

Methodology...................................................................................................................... 70

End-members.................................................................................................................... 71

Aquifer characterisation........................................................................................................71

Ambient groundwater ...........................................................................................................71

Source water ........................................................................................................................71

Mineral equilibrium and mixing.......................................................................................... 72

Metal mobilisation ............................................................................................................. 72

Observed water quality changes....................................................................................... 72

Aquifer dissolution............................................................................................................. 73

Appendix 7 Entry level assessment for ASTR........................................................82

Appendix 8 ASTR risk management plan ...............................................................87

Operational residual risk assessment for the Salisbury stormwater ASTR project Page v

LIST OF TABLES

Table 1 Components of stormwater reuse via the ASTR system ........................................... 5 Table 2 Generalized hydrogeological units at ASTR site (modified from AGT (2007) and

Gerges, (2005); from Kremer et al. (2008)) .............................................................. 6 Table 3 Quantities of water injected and extracted in ASTR well system, from September

2006 to March 2009. ................................................................................................ 8 Table 4 ASTR system pre-treatment performance (cleansing reedbed removal efficiencies

2006 – 2008).......................................................................................................... 12 Table 5 List of laboratories that performed analyses for the ASTR project, 2006-2009 ........ 15 Table 6 Maximal risk assessment summary......................................................................... 33 Table 7 Residual risk assessment summary ........................................................................ 33 Table A1-1 ASTR reedbed inlet (WE1) water quality data summary 2006-2008 .................. 44 Table A1-2 ASTR reedbed outlet (WE2) water quality data summary 2006-2008 ................ 48 Table A1-3 Maximum concentrations (ng/L) detected by passive samplers at the cleansing

reedbed inlet (WE1) ............................................................................................... 52 Table A2-1 Ambient groundwater (RW1 RW3, IW3) quality data 2006 ................................ 53 Table A2-2 Groundwater quality data 2007-2008................................................................. 54 Table A2-3 Recovered water quality (RW wells) in 2009...................................................... 57 Table A3-1 Organic chemicals analysed for but not detected in the ASTR scheme ............. 59 Table A3-2 Organic chemicals detected in the ASTR scheme ............................................. 62 Table A4-1 Recommended revised monitoring suite............................................................ 63 Table A5-1 Stochastic parameters used in Monte Carlo simulation...................................... 66 Table A5-2 Example QMRA calculation for rotavirus ........................................................... 67 Table A5-3 Risk Characterisation results (DALYs)............................................................... 67 Table A5-4 Sensitivity analysis of microbiological hazards................................................... 68 Table A6-1 Mineralogy of the T2 aquifer core samples ........................................................ 75 Table A6-2 Major elemental composition of the T2 aquifer core material ............................. 75 Table A6-3 Trace elemental composition of the T2 aquifer core material determined by X-

Ray Fluorescence .................................................................................................. 76 Table A6-4 Additional trace elements that were below that X-Ray Fluorescence detection

limit ........................................................................................................................ 76 Table A6-5 Physio-chemical characteristics of the T2 aquifer core material......................... 77 Table A6-6 Chemical composition of the source water and groundwater used in the

PHREEQC simulations or observed during the ASTR field trial.............................. 78 Table A6-7 Saturation indexes for the receiving groundwater, the potential source waters,

mixtures of the ambient groundwater and the source water and during the injection, storage and recovery phases of the ASTR trial ...................................................... 79

Table A7-1 Entry-level risk assessment — Part 1: viability................................................... 82 Table A7-2 Entry-level risk assessment — Part 2: degree of difficulty.................................. 83 Table A7-3 Summary of degree of difficulty ......................................................................... 86

Operational residual risk assessment for the Salisbury stormwater ASTR project Page vi

LIST OF FIGURES

Figure 1 Risk assessment stages in managed aquifer recharge project development (EPHC-NHMRC-NRMMC 2008a)......................................................................................... 3

Figure 2 City of Salisbury water harvesting facilities in the Parafield area, identifying the location of wells at the ASTR and Parafield ASR sites (after Kremer et al. 2008) ..... 4

Figure 3 Close up of ASTR well and piezometer configuration (from Kremer et al. 2008). ..... 5 Figure 4 Conceptual diagram of the ASTR system, showing critical control points (CCPs),

quality control points (QCPs), water and sediment quality sampling points (after Page et al. 2008)...................................................................................................... 6

Figure 5 Cumulative volume injected and recovered from the start of ASTR operation in September 2006 up to April 2009. This includes flushing phase (injection into RW wells) from September 2006–June 2008, commencement of injection into IW wells in September 2008 and commencement of recovery in February 2009.................. 10

Figure 6 Time versus depth-average EC data obtained from down-hole profiles over the opened intervals, and EC data collected during sampling, at the observation wells IW1, IW2, IW3 and IW4 during the flushing phase from September 2006 to August 2008, showing the breakthrough of source water in the aquifer. Injection periods at the RW wells are shown with grey shading. ........................................................... 21

Figure 7 DALYs as a function of the multiple barriers of the ASTR scheme (dotted line indicates ‘tolerable risk’ set at 10–6 DALYs per person per year) ............................ 24

Figure 8 Progress of the ASTR plan against the 12 elements of the Australian Guidelines for Water Recycling ..................................................................................................... 40

Figure A6-1 Decision tree used to identify potential for arsenic release from the aquifer

sediments (EPHC-NHMRC-NRMMC 2008a).......................................................... 80 Figure A6-2 Decision tree used to identify the potential for iron release from the aquifer

sediments (EPHC-NHMRC-NRMMC 2008a).......................................................... 81

Operational residual risk assessment for the Salisbury stormwater ASTR project Page vii

ACKNOWLEDGEMENTS

The Salisbury Aquifer Storage Transfer and Recovery (ASTR) Research Project is supported by the Australian Government Department of Innovation, Industry, Science and Research (DIISR) through its International Science Linkages Programme, enabling participation within the European Union Project 'Reclaim Water', which is supported in the 6th Framework Programme (Contract 018309) with coordination in Australia by United Water. The ASTR project was also supported by the South Australian Premier’s Science and Research Foundation and the Australian Government National Water Commission through the Water Smart Australia Programme commitment to Water Proofing Northern Adelaide Project. Project partners City of Salisbury provided data on water quality and system operation for the Parafield stormwater harvesting system; United Water provided project management and logistical support, water quality sampling, down-hole profiling, general field services and financial support to laboratory analyses; SA Water through the Australian Water Quality Centre provided in-kind contributions towards laboratory analyses; the Department of Water, Land, Biodiversity and Conservation’s geological technical unit provided in-kind contributions to early aquifer characterisation investigations; and the CSIRO provided research services. Members of the ASTR HACCP committee provided valuable input into the production of this revised HACCP plan. Membership of the committee included:

• Declan Page, Peter Dillon (CSIRO)

• Rudi Regel, Stephanie Rinck-Pfeiffer (United Water)

• Peter Newland (SA EPA)

• David Cunliffe (SA Department of Health)

• Mark Purdie, Bruce Naumann (City of Salisbury)

• Alex Keegan, Glynn Ashman, Chris Marles, Lester Sickerdick (SA Water).

• Neil Power (DWLBC)

Operational residual risk assessment for the Salisbury stormwater ASTR project Page viii

EXECUTIVE SUMMARY

The aquifer storage transfer and recovery (ASTR) project at Salisbury aims to determine whether reedbed-treated stormwater that has been stored in an initially brackish aquifer can be recovered at drinking water quality.

This risk assessment report is the third in a series following on from Preliminary hazard analysis and critical control point (HACCP) – Salisbury stormwater to drinking water aquifer storage and transfer (ASTR) project (Swierc et al. 2005) and Preliminary quantitative risk assessment for the Salisbury stormwater ASTR project (Page et al. 2008). Each successive report is based on a significantly expanded set of monitoring results allowing for a more quantitative and reliable assessment of risks. The first assessment by Swierc et al. (2005) was based only on very limited data on stormwater quality, groundwater quality from nearby existing wells and catchment characteristics. The second assessment by Page et al. (2008) was based on a full year of monitoring in 2006 of water quality entering and leaving the Parafield stormwater harvesting system. This current report draws on water quality monitoring at the Parafield stormwater harvesting system over the three years from 2006 to 2008 and the groundwater monitoring undertaken since injection commenced at the ASTR site in September 2006, through to March 2009. A distinguishing feature of this report is that it follows the risk assessment process of the draft Australian Guidelines for Water Recycling 2C: Managed Aquifer Recharge (EPHC–NHMRC–NRMMC 2008a) and also addresses the Australian Guidelines for Water Recycling 2A: Augmentation of Drinking Water Supplies (EPHC–NHMRC–NRMMC 2008b).

Risks were assessed for the ASTR system for twelve hazard types identified in the draft Managed Aquifer Recharge Guidelines (EPHC–NHMRC–NRMMC 2008a). Of these, several water quality hazards received increased attention as it became evident that these carried a higher level of risk. This included a revised quantitative microbial risk assessment (QMRA) for the index pathogens (rotavirus, Cryptosporidium and Campylobacter). The QMRA incorporated the results of recently completed pathogen decay chamber studies by Toze et al. (2008, 2009) to describe the decay of these pathogens in the reedbed and aquifer treatment barriers of the ASTR system.

The results of the 2006–2008 monitoring program were used to determine the removal efficiencies for the cleansing reedbed component of the ASTR system as a step to quantitatively assess the treatment performance for physical, chemical and microbial hazards. The water produced after the Parafield stormwater harvesting system was found to be near potable quality. The mean water quality parameters which exceeded the drinking water guidelines prior to recharge included colour, caused by elevated iron concentrations and small numbers of faecal indicator bacteria from fauna in the reedbed.

The revised QMRA indicated that the residual risks posed by the microbial hazards were currently acceptable with supplementary disinfection. Residual risks from organic chemicals were assessed to be acceptable but further validation and verification monitoring is required to confirm this.

The subsurface storage component of the ASTR scheme has not advanced enough to fully evaluate the risk from inorganic chemical hazards and turbidity. This preliminary assessment suggests there is a residual risk of iron exceeding Australian drinking water aesthetic guidelines unless further treatment such as aeration for iron removal is considered. Although arsenic concentrations in recovered water have continuously been significantly lower than concentrations acceptable for drinking water supplies, the elevated concentration of arsenic in native groundwater and its presence in aquifer minerals suggest that the assessment of residual risk from arsenic, as for iron, awaits more complete flushing of the storage zone between injection and recovery wells. Together with implementing early warning monitoring in the intermediate piezometers and geochemical modelling, this will allow more rigorous assessment of the potential for metal mobilisation from the aquifer and methods to avoid this

Operational residual risk assessment for the Salisbury stormwater ASTR project Page ix

if necessary. The evaluation of hydrogeochemical processes was largely based on the operation of the ASTR site in the flushing mode, with injection occurring via the central recovery wells (RW). Further injection via the outer injection wells (IW) is necessary to assess the impact on the quality of recovered water of subsurface processes, particularly carbonate mineral dissolution, redox reactions and the aquifer’s capacity to remove turbidity and organic chemicals.

Recommendations for the risk assessment and management of the ASTR system focus on the draft Managed Aquifer Recharge Guidelines (EPHC–NHMRC–NRMMC 2008a) and include monitoring and acquiring information to refine the risk assessment, involving the urban catchment, the stormwater capture and treatment system and aquifer processes and any potential post-recovery treatment. This leads to recommendations concerning communication about the risks and other steps required before recovered water could be considered for introduction into mains supplies.

Operational residual risk assessment for the Salisbury stormwater ASTR project Page 1

1. INTRODUCTION

This revised risk assessment report summarises the risk assessment research performed at the Parafield Stormwater Harvesting System and the Aquifer Storage Transfer and Recovery (ASTR) project located at Salisbury in South Australia. Since the beginning of the ASTR project, the Australian Guidelines for Water Recycling have been extended with second phase guidelines that are relevant to the ASTR project – Phase 2A: Augmentation of Drinking Water Supplies (EPHC–NHMRC–NRMMC 2008b); the draft Phase 2B: Stormwater Harvesting and Reuse (EPHC–NHMRC–NRMMC 2008c) and the draft Phase 2C: Managed Aquifer Recharge (‘draft MAR Guidelines’: EPHC–NHMRC–NRMMC 2008a). As such there is a need to review the risk assessment in light of these new guidelines as part of project development. The key hazards presented in the draft MAR Guidelines were reviewed with respect to the accumulated data from 2006 to 2009. Special emphasis was placed on pathogen risks consistent with the Augmentation of Drinking Water Supplies Guidelines. Analysis of the summary results also gives a rationale for further risk-based management plans to support future feasibility assessments of connecting the ASTR recycled stormwater to the mains water supply.

Previous risk assessment reports for the ASTR project have taken qualitative (Swierc et al. 2005) and preliminary quantitative (Page et al. 2008) approaches in assessing the risks to human health and the environment. Several knowledge gaps requiring new studies were identified by Page et al. (2008) including recent pathogen decay chamber studies (Toze et al. 2008, 2009), use of passive samplers to detect trace levels of organic chemicals, characterisation of the aquifer using aquifer core samples collected during drilling of the piezometers and analysis of the recovered water quality following extraction of water from the subsurface. These were performed in 2008 and 2009 and were incorporated in this revised quantitative risk assessment.

This report reviews the accumulated results of the 2006–2009 water quality monitoring program and investigates the revised application of QMRA to the Salisbury ASTR project and covers stormwater harvesting, cleansing reedbed treatment, and subsurface storage and subsequent recovery to drinking water supply. This is used to further evolve the development of a risk management plan for the ASTR project, with the aim to ensure product safety and proactively meet evolving regulator requirements. This report does not address processes affecting the quality of the stormwater runoff in the catchment which was beyond the scope of the current study nor the risks associated with diverting additional stormwater from the Cobbler Creek catchment into the Parafield stormwater harvesting system as intended in the future.

1.1. Risk assessment stages

The risk assessment framework set out in the Australian Guidelines for Water Recycling: 2A Augmentation of Drinking Water Supplies (EPHC–NHMRC–NRMMC 2008b) and Draft - 2C Managed Aquifer Recharge (EPHC–NHMRC–NRMMC 2008a) has been applied to the ASTR project and details on each relevant hazard are given in this section.

The risk assessment framework encompasses four stages of project development and assessment, with the information required for assessment at each stage increasing in complexity. The four stages are shown in Figure 1 and are summarised below. Stages 1 and 2 of the ASTR project have been completed and are covered in Pavelic et al. (2004), Swierc et al. (2005), Page et al. (2008), and Kremer et al. (2008) and this report covers Stage 3. Stage 4 begins when water is recovered under continuous operating conditions.

Stage 1

Stage 1 of the risk assessment framework comprised a desktop study where all available information was collected, and used to undertake an entry level assessment. A copy of the entry level assessment is given in Appendix 7. This was intended to reveal the likely degree


of difficulty of the MAR project, and hence the extent of field investigations needed in Stage 2. Issues addressed in Stage 1 included the type and scale of the scheme, the existence of a suitable aquifer, the availability of source water, and intended uses of recovered water. Environmental values, management capability and compatibility with catchment and groundwater management plans were also assessed. The entry level assessment showed the scheme to be apparently viable, and more detailed investigations were undertaken in Stage 2.

Stage 2

Collecting necessary information required drilling, analysis of source and native groundwater quality, and basic modelling (Pavelic et al. 2004). The physical characteristics and geochemical conditions of the aquifer were identified, and operational issues such as source water pre-treatment and clogging potential were addressed. A maximal risk assessment was undertaken (Swierc et al. 2005), which estimated the risks in the absence of any controls or preventive measures. Where the maximal risks were moderate or high, preventive measures were identified and modelled to validate effects. A pre-commissioning residual risk assessment was then performed, which forecast residual risk (Page et al. 2008).

Stage 3

As the risk assessments conducted in Stage 2 showed the residual risks to be mostly acceptable, the project moved into the third stage of commissioning. The scheme was trialled to validate the effectiveness of preventive measures and operational controls (Page et al. 2008), and to assess the suitability of recovered water for intended uses. This current report presents a revised residual risk assessment consistent with the Augmentation of Drinking Water Supplies Guidelines and Draft MAR Guidelines. This stage identifies any unforseen residual risks, and the management of these can be addressed by targeted studies. More detailed modelling has been undertaken at this stage (Kremer et al. 2008) to estimate the residence time and salinity of recovered water under various ASTR operational practices.

Stage 4

If residual risks are deemed to be low, the project can move into operation, with a management plan and regular operational monitoring. Verification monitoring must be performed to assess the quality of the recovered water, and to verify that environmental values of the aquifer are protected.

In progressing the stages of the risk assessment, the Draft MAR Guidelines identify twelve hazards to human health or the environment:

• Pathogens

• Inorganic chemicals

• Salinity / Sodicity

• Nutrients

• Organic chemicals

• Turbidity / particulates

• Radionuclides

• Pressure, flow rates, volumes, water levels

• Contaminant migration through preferential flow paths

• Aquifer dissolution and stability

• Aquifer and groundwater dependent ecosystems

• Energy and greenhouse gasses

The water quality data on the first seven hazards are discussed in Sections 4 and 5, and the risks associated with all twelve hazards are assessed in Section 6.


Collect available information & data

Undertake entry level assessment

Identify information gaps

Conduct investigations and acquire

identified necessary information

Stage 1

Desktop

study

Project apparently viable

Operate project

Undertake pre-commissioning

residual risk assessment

Operational residual risk assessment

Stage 3

Construction

&

commissioning

Low

inherent

risk

Project not

viable

Identify preventive measures

Model & validate effects

Identify commissioning trials

Construct project

Trial preventive measures

Stage 4

Operation

Moderate or high residual risk

Low residual risk

Low residual risk

Moderate or

high residual

risk

Undertake maximal risk assessment

No

Moderate or

high residual

risk

Stage 2

Investigations

&

assessment

Yes

Are preventive measures feasible?

Does project meet criteria for

Simplified Assessment? Yes

No

Use

Simplified

Assessment

Process

Refine risk management plan

Draft risk management plan

Figure 1 Risk assessment stages in managed aquifer recharge project development (EPHC-NHMRC-NRMMC 2008a)


2. ASTR SYSTEM CONFIGURATION

The location and configuration of the ASTR system, comprising the Parafield Stormwater Harvesting System (harvesting and pre-treatment) and the ASTR well field (subsurface storage) are shown in Figures 2 and 3. The nearby Parafield ASR wells are of interest due to their impact on the hydraulic gradient in the aquifer, which affects the operation of the ASTR site (Section 6.8). The Parafield ASR scheme also relies on the source water from the Parafield reedbeds, and its recovered water has been used as source water for the ASTR system (Section 3.2).

The Draft MAR Guidelines (EPHC–NHMRC–NRMMC 2008a) describe seven components of a system for water recycling via MAR which can be defined for the ASTR system (Table 1). These components can also be identified in Figure 4, which shows the route of water flow and the treatment train for the ASTR system. Details on the critical control points (CCPs) and quality control points (QCPs) can be found in Swierc et al. (2005) and Page et al. (2008). Each of the CCPs and QCPs is the location for a water quality monitoring point. The results of the water quality monitoring are discussed in Section 4.

Figure 2 City of Salisbury water harvesting facilities in the Parafield area, identifying the location of wells at the ASTR and Parafield ASR sites (after Kremer et al. 2008)


Figure 3 Close up of ASTR well and piezometer configuration (from Kremer et al. 2008).

Table 1 Components of stormwater reuse via the ASTR system

Component ASTR system

1. Capture zone Parafield stormwater harvesting system (Parafield drain, in-stream basin, holding storage)

2. Pre-treatment Passive treatment in the cleansing reedbed

3. Recharge Injection wells (IW1, IW2, IW3, IW4)

4. Subsurface storage T2 aquifer – confined limestone Tertiary aquifer

5. Recovery Recovery wells (RW1, RW2)

6. Post-treatment Currently none – post-treatment measures discussed in Section 6 include UV and chlorine disinfection

7. End use Currently discharged to storage tanks, then distributed to end-users such as Mawson Lakes non-potable supply and municipal irrigation. Potential future use in drinking water supply being evaluated.


Figure 4 Conceptual diagram of the ASTR system, showing critical control points (CCPs), quality control points (QCPs), water and sediment quality sampling points (after Page et al. 2008)

The target aquifer of the ASTR project is a confined limestone Tertiary aquifer approximately 60 meters thick (from 160 to 220 m below ground), known as the T2 aquifer, which can be divided into three units called T2a, T2b and T2c (Table 2; Gerges 2005). The ASTR system is a six-well system progressively drilled from May 2006 to January 2007 including two inner recovery wells RW1 and RW2, and four outer injection wells IW1, IW2, IW3 and IW4, with inter-well spacing of 50m between each injection well and its nearest recovery well, as shown on Figure 3 . Details on the ASTR well field configuration and local hydrology can be found in Pavelic et al. (2004) and Kremer et al. (2008). Three piezometers located along the IW1-RW1 transect were drilled in July 2008 for monitoring purposes. The six ASTR wells are completed within units T2ab over an open interval of about 17 m from 165 to 182 m below ground. Piezometers P1 and P3, respectively 10 m and 30 m from IW1, are open in unit T2a from 165.5 m below ground over about 3 m; while P2, located 20 m from IW1, is open in unit T2c from 210 to 215 m below ground.

Table 2 Generalized hydrogeological units at ASTR site (modified from AGT (2007) and Gerges, (2005); from Kremer et al. (2008))

Interval (m bgs)

Lithology Aquifer Stratigraphic name

Overlying aquifers

152.5 - 160 Clay Confining bed Munno Para Clay

160 - 172 Limestone (grey to white) moderately cemented

T2a unit

172 - 187

Limestone (grey to yellow) well cemented interbedded with sand/silt

T2b unit

187 - 220 Limestone, sand highly fossilifereous

T2c unit

T2 Lower Port Willunga Formation

220 - >222* Confining bed Ruwarung member

* Drilling confirmed presence of clay to 222 m bgs. Max thickness of Ruwarung member is 22 m

(Geoscience Australia website, accessed 24/03/2009 at 1:30PM

http://dbforms.ga.gov.au/pls/www/geodx.strat_units.def?strno=16480&stratname=Ruwarung%20Member )


3. SYSTEM OPERATION AND MONITORING 2006-2009

This section details volumes of rainfall, stormwater captured by the Parafield stormwater harvesting system, and injected and recovered water at the ASTR well-field between September 2006 and March 2009. Water quality monitoring techniques are discussed, and the treatment provided by the cleansing reedbed and aquifer is assessed. Finally, laboratories used for analyses are listed.

3.1. Rainfall and quantities captured by the Parafield stormwater harvesting system 2006-2008

From September 2006 to August 2008 (the record of the Supervisory Control and Data Acquisition (SCADA) system data available for the Parafield stormwater harvesting system) there was a total of 688 mm of rainfall at the Parafield Airport weather station (compared to an annual average of 453 mm) which resulted in a total of 1,610 ML of stormwater over the two year period being harvested by the Parafield system (compared to a designed maximum of ~1,100 ML/yr). Monthly rainfall was both low and variable, with a minimum of 0 mm, mean of 28.7 mm and maximum of 83.2 mm in any given month. Flows through the reedbed system were fairly stable but generally higher in the winter months (June to August) when there was greater rainfall. However, due to recovery of water from the Parafield ASR wells to supply the reedbed during dry periods, the correlation of reedbed outflows and monthly rainfall is distorted. The below average rainfalls (76% of average) have limited the quantities of stormwater that could be captured by the system and potentially may have affected the quality of water generated by the system.

A water and salt budget for a four week period has previously been calculated by Page et al. (2008) with the aim of quantifying the treatment capacity of the cleansing reedbed. In this report a summary of the outflows from the Parafield stormwater harvesting system is presented from the onset of the commissioning of the SCADA system in September 2006 until its decommissioning in August 2008.

3.2. ASTR well system quantities injected and extracted 2006-2009

Data for the volumes of water injected and extracted along with the dates that injection and recovery began and ended from September 2006 to March 2009 at all ASTR wells are presented in Table 3, and summarised in Figure 5. In some instances, water extracted from the Parafield ASR site was recirculated through the reedbed contributing to the reedbed outflows and the source water for injection via the ASTR wells.

From September 2006 to June 2008, 377 ML had been injected into the RW wells during the flushing phase (Table 3), when the aquifer was flushed to create a bubble of fresh water as discussed by Kremer et al. (2008). Parafield extracted ASR water was at times used as source water during flushing after recirculation through the cleansing reedbed prior to being injected at ASTR. Additional pipe and storage tank infrastructure was added in late 2008 and water extracted from the ASR and ASTR well fields in the future will be directly pumped to the storage tanks, and not recirculated through the reedbed.

During the injection phase from September 2008 to January 2009, 30 ML was injected in the IW wells. A small volume of water (<1 ML) was recovered during sampling of the RW wells in September 2008; and from February to March 2009, 29 ML was recovered from the RW wells.

Operational residual risk assessment for the Salisbury storm

water ASTR project

Page 8

Tab

le 3

Qu

an

titi

es

of

wate

r in

jecte

d a

nd

ex

tracte

d i

n A

ST

R w

ell s

ys

tem

, fr

om

Sep

tem

ber

20

06 t

o M

arc

h 2

00

9.

Inje

cte

d (

ML

) E

xtr

acte

d (

ML

)

Mo

nth

ly T

ota

ls

Mo

nth

ly T

ota

ls

Mo

nth

ly T

ota

ls

Mo

nth

RW

1

RW

2

Cu

mu

lati

ve

vo

lum

e

inje

cte

d -

RW

IW

1

IW2

IW3

IW4

Cu

mu

lati

ve

vo

lum

e

inje

cte

d -

IW

R

W1

RW

2

Cu

mu

lati

ve

vo

lum

e

extr

ac

ted

Date

: E

ven

t

Sep-06

3.6

2.9

6.6

0

0

0

0

0

0

0

0

7: Injection started (RW) -

reedbed w

ater

Oct-06

9.4

7.8

23.8

0

0

0

0

0

0

0

0

3: Switched to Parafield ASR

water

Nov-06

14.1

11.9

49.8

0

0

0

0

0

0

0

0

14: Switched to reedbed w

ater

Dec-06

13.9

13.0

76.7

0

0

0

0

0

0

0

0

Jan-07

2.1

0.0

78.8

0

0

0

0

0

0

0

0

2: Injection stopped

Feb-07

0.0

0.0

78.8

0

0

0

0

0

0

0

0

Mar-07

0.0

0.0

78.8

0

0

0

0

0

0

0

0

Apr-07

0.0

0.0

78.8

0

0

0

0

0

0

0

0

May-07

9.2

7.6

95.6

0

0

0

0

0

0

0

0

1: Injection started (RW) –

reedbed w

ater

Jun-07

11.0

9.2

115.8

0

0

0

0

0

0

0

0

Jul-07

12.2

13.2

141.1

0

0

0

0

0

0

0

0

Aug-07

16.1

11.4

168.6

0

0

0

0

0

0

0

0

20: Switched to Parafield ASR

water

Sep-07

6.5

5.9

181.0

0

0

0

0

0

0

0

0


Oct-07

0.0

0.0

181.0

0

0

0

0

0

0

0

0

Nov-07

8.7

7.6

197.2

0

0

0

0

0

0

0

0

19: Injection started (RW) –

Parafield ASR w

ater

Dec-07

15.7

13.8

226.7

0

0

0

0

0

0

0

0


19: Injection started – Parafield

ASR w

ater

Jan-08

20.1

17.5

264.3

0

0

0

0

0

0

0

0

Feb-08

11.9

11.7

287.9

0

0

0

0

0

0

0

0

Mar-08

14.6

0.7

303.1

0

0

0

0

0

0

0

0

Apr-08

4.5

9.4

317.0

0

0

0

0

0

0

0

0

May-08

8.8

21.9

347.6

0

0

0

0

0

0

0

0

Jun-08

14.9

14.3

376.9

0

0

0

0

0

0

0

0


Jul-08

0

0

376.9

0

0

0

0

0

0

0

0


water ASTR project

Page 9

Inje

cte

d (

ML

) E

xtr

acte

d (

ML

)

Mo

nth

ly T

ota

ls

Mo

nth

ly T

ota

ls

Mo

nth

ly T

ota

ls

Mo

nth

RW

1

RW

2

Cu

mu

lati

ve

vo

lum

e

inje

cte

d -

RW

IW

1

IW2

IW3

IW4

Cu

mu

lati

ve

vo

lum

e

inje

cte

d -

IW

R

W1

RW

2

Cu

mu

lati

ve

vo

lum

e

extr

ac

ted

Date

: E

ven

t

Aug-08

0

0

376.9

0

0

0

0

0

0

0

0

Sep-08

0.1

0

377.0

3.3

3.6

0.5

3.0

10.3

0.3

0.7

1.0

3: Injection started (IW

) –

reedbed w

ater

Oct-08

0

0

377.0

1.7

1.9

0.1

1.7

15.6

0

0

1.0

Nov-08

0

0

377.0

0

0

0.1

0

15.8

0

0

1.0

Dec-08

0

0

377.0

4.1

3.5

2.3

4.1

29.8

0

0

1.0

Jan-09

0

0

377.0

0

0

0.2

0

30.0

0

0

1.0

Feb-09

0

0

377.0

0

0

0.5

0

30.5

11.5

9.6

22.1

1: Extraction started

Mar-09

0

0

377.0

0

0

0.7

0

31.2

20.0

17.0

59.1


0

50

100

150

200

250

300

350

400

450

Aug-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09

Cumulative volume (ML)

RW1 RW2 IW Total ASTR

Flushing Injection RecoveryFlushing Flushing

Figure 5 Cumulative volume injected and recovered from the start of ASTR operation in September 2006 up to April 2009. This includes flushing phase (injection into RW wells) from September 2006–June 2008, commencement of injection into IW wells in September 2008 and commencement of recovery in February 2009.

3.3. Water quality monitoring in Parafield stormwater harvesting system 2006-2008

Water quality monitoring as grab sampling was undertaken during 2006–2008 at the inlet (WE1; 16 sampling events) and outlet (WE2; 34 sampling events) of the cleansing reedbed of the Parafield stormwater harvesting system (Figure 4). A compilation of the available water quality data for the Parafield stormwater harvesting system is given in Appendix 1. Of primary interest is the quality of the product water leaving the cleansing reedbed (WE2). This is because the outflows from the cleansing reedbed are used as injectant for the subsurface component of the ASTR system. EC and temperature were monitored continuously in the reedbed from September 2006.

Outflows have been largely steady (Figure 5); grab-sampling was performed to obtain estimates of average hazard concentrations on an annual basis. Some targeted composite sampling was undertaken in 2007 and 2008. Previous work at the ASTR site used passive samplers to monitor organic chemicals (Page et al. 2008). A summary of the organic chemicals detected with the passive samplers and their maximum concentrations is given in Appendix 1, Table A1-3. No values exceeded the Australian Drinking Water Guidelines (NHMRC–NRMMC 2004).

A review of all results in Appendix 1 shows that the majority of these parameters already meet the Australian Drinking Water Guidelines prior to transfer to the subsurface storage component of the system. Exceptions to this include: iron and the majority of the microbiological indicators. As noted by Page et al. (2008) iron and the indicator organisms have likely sources within the reedbed itself. Colour and iron are mostly derived from the release of iron from the sediments caused by changes in stormwater quality, and faecal indicator organisms may originate from warm blooded animals (e.g. water birds) that have been observed in the cleansing reedbed itself.


A brief summary discussion of the water quality monitoring data with respect to the hazards defined by the draft MAR Guidelines (EPHC–NHMRC–NRMMC 2008a) in the order proposed by those guidelines is given in Section 4.

3.4. Assessment of the Parafield stormwater harvesting system treatment performance

Reedbeds are passive systems commonly used for improving stormwater quality. The efficacy of the Parafield stormwater harvesting cleansing reedbed pre-treatment barrier for ASTR has been previously quantitatively assessed by Page et al. (2008) but for only a limited four week period.

A simplified method to determine removal efficiency (RE) of the system (e.g. Marks et al. 2005) for any solute uses the relative reduction in concentration of that solute between reedbed inflows and outflows based on concurrent grab sample concentrations:

1

21WE

WERE −=

where WE1 is the concentration of the parameter in the reedbed inlet, WE2 is the concentration of the parameter in the reedbed outlet and RE is the calculated removal efficiency.

As discussed by Page et al. (2008) this approach to calculation of the RE which does not account for residence time in the wetland is only valid if sufficiently large number of data are used that changes in flow and storage within the system are balanced out. A summary of the average water quality data for the period 2006–2008 and the REs for the cleansing reedbed by year and an average for the period 2006-2008 are given in Table 4. Removal efficiencies are only presented for those parameters where sufficient data exists. Removal efficiencies are discussed with reference to the hazards assessed in the order described by the Draft MAR Guidelines (EPHC–NHMRC–NRMMC 2008a) in the following sections.

Of the parameters shown in Table 4, a number had mean values at the reedbed inlet (WE1) that exceeded Australian Drinking Water Guidelines: turbidity, colour, all microbiological indicators and total iron. Hence, as shown later in Section 6, using maximum concentrations measured, a maximal risk assessment identifies these as the hazards of greatest concern, and for which an assessment of aquifer treatment as a preventive measure would be required as part of the residual risk assessment.

The number of water quality parameters evaluated in Appendices 1 and 3 is much larger. Other parameters exceeding Australian Drinking Water Guidelines are Clostridium spores and Campylobacter. Section 4 contains more details.


water ASTR project

Page 12

Tab

le 4

AS

TR

sys

tem

pre

-tre

atm

en

t p

erf

orm

an

ce

(c

lean

sin

g r

ee

db

ed

re

mo

val

eff

icie

ncie

s 2

00

6 –

200

8)

A

ustr

ali

an

Dri

nkin

g

Wate

r G

uid

eli

ne

Valu

e

Av

era

ge

WE

1

Av

era

ge

WE

2

RE

20

06

RE

200

7

RE

20

08

RE

Av

era

ge

20

06

–2

008

Mark

s

et al.

(200

5)*

Pag

e

et al.

(2

008)*

Ph

ysic

al ch

ara

cte

risti

cs

Conductivity (µS/cm)

1,000

210

242

-0.27

0.06

-0.14

-0.15

-0.07

Suspended Solid

s (mg/L)

- 14.8

4.0

0.90

0.17

0.56

0.73

0.77

0.73

Total Dissolved Solid

s (by EC; mg/L)

500

115

133

-0.29

0.04

-0.13

-0.16

0.60

-0.06

Turbidity (NTU)

5

17.2

4.0

0.85

0.57

0.73

0.77

0.79

0.51

True C

olour (H

U)

15

66

47

0.29

0.29

Majo

r Io

ns (

mg

/L)

Alkalinity as Calcium C

arbonate

200

55

69

-0.21

-0.02

-0.36

-0.25

0.04

Bicarbonate

- 67

84

-0.21

-0.03

-0.36

-0.25

0.37

Bromide

- 0.03

0.06

-0.17

0.00

-0.74

Sulfate

250

10

10

-0.01

0.11

-0.05

0.00

-0.04

Chloride

250

27

27

-0.18

0.09

-0.13

-0.02

0.56

Fluoride

1.5

0.16

0.16

0.14

0.00

-0.07

-0.04

0.47

Calcium

- 18

22

-0.39

0.03

-0.13

-0.21

0.73

Magnesium

- 3.7

4.8

-0.39

0.03

-0.19

-0.29

0.40

Potassium

- 3.5

3.8

0.00

0.06

-0.07

-0.09

0.05

Sodium

180

16.9

18.3

-0.15

0.06

-0.19

-0.08

0.04

Mic

rob

iolo

gic

al

Coliform

s (cfu/100 m

L)

- 28,455

4,441

0.90

0.87

0.84

0.99

E. coli (cfu/100 m

L)

0

77

35

0.33

0.82

-0.30

0.55

0.65

0.93

Enterococci (cfu/100 m

L)

0

85

24

-0.33

0.80

0.66

0.71

0.99

therm

otolerant coliform

s (cfu/100 m

L)

0

91

36

0.33

0.85

0.02

0.61

0.93

Faecal Streptococci (cfu/100 m

L)

0

85

24

-0.33

0.80

0.66

0.71

0.99

Nu

trie

nts

(m

g/L

)

Ammonia as N

0.5

0.11

0.02

0.83

0.70

0.94

0.78

0.83

Nitrate plus Nitrite

50

0.06

0.01

0.06

0.92

0.94

0.86

Nitrogen - Total

- 0.74

0.42

0.48

0.48

0.43

0.43

0.59

0.63

TKN as Nitrogen

- 0.67

0.41

0.48

0.39

0.37

0.39

0.62

Phosphorus - Total

- 0.09

0.05

0.51

0.32

0.61

0.43

0.64

0.75

Phosphorous - D

issolved

0.02

0.01

0.29

0.56

0.64

0.38

Dissolved O

rganic C

arbon

- 6.9

6.1

0.15

0.23

0.19

0.12

0.63


water ASTR project

Page 13

A

ustr

ali

an

Dri

nkin

g

Wate

r G

uid

eli

ne

Valu

e

Av

era

ge

WE

1

Av

era

ge

WE

2

RE

20

06

RE

200

7

RE

20

08

RE

Av

era

ge

20

06

–2

008

Mark

s

et al.

(200

5)*

Pag

e

et al.

(2

008)*

Total Organic Carbon

- 8.5

6.9

0.31

0.17

0.22

0.18

0.81

0.62

UV Absorbance - 254 nm (filtered)

- 0.25

0.25

0.12

0.19

0.19

0.02

0.53

Meta

ls (

mg

/L)

Aluminum - Total

0.3

0.3

2

0.17

0.49

0.22

0.52

0.48

0.31

Iron - Total

0.3

0.4

7

0.5

4

-0.16

-0.33

0.31

-0.16

0.35

-1.71

Iron - Soluble

0.3

0.22

0.18

0.12

0.02

0.59

0.17

-0.32

Lead - Total

0.01

0.002

0.001

0.68

0.69

0.80

0.72

0.67

0.86

Manganese - Total

0.1

0.025

0.045

-0.60

-0.39

-0.65

-0.80

-0.49

Manganese - Soluble

0.1

0.017

0.021

-0.15

-0.02

-0.23

0.69

0.29

Zinc - Total

3

0.049

0.022

0.47

0.68

0.73

0.56

0.48

0.81

* REs are uncorrected for chloride

Bo

ld indicates value in exceedance of Australian D

rinking W

ater Guidelin

es.


3.5. Groundwater water quality monitoring in ASTR system 2006-2009

In June 2006, prior to any injection at the ASTR site, ambient water quality samples were collected from the recently constructed RW1, RW2 and IW3 wells (Appendix 2: Table A2-1). The conditioning or flushing phase of the trial was undertaken between September 2006 and June 2008 with injection into the two RW wells. Periodic groundwater sampling (20 sampling events) and down-hole water quality profiling was carried out in the ASTR wells during the flushing operations to asses the quality of water and to track the evolution of breakthrough (Table A2-1). Wells were sampled using a conventional monitoring pump, with three bore volumes displaced prior to sample collection. Temperature, electrical conductivity (EC), dissolved oxygen (DO), pH and redox potential (Eh) were measured in the field during pumping using a TPS 90FLMV field lab analyser. Once these values had stabilised samples were collected. Down-hole EC and temperature profiles were performed approximately monthly at IW1, IW2, IW3 and IW4 wells using a YSI 600XML down-hole water quality analyser. Additional down-hole conductivity, temperature and depth loggers (CTD-Diver, Van Essen Instruments) were installed in observation wells IW1 and IW3 to a depth of ~175 m in June 2007.

Injection into the RW wells ceased at the end of June 2008. In August 2008, water quality sampling was performed in all four IW wells and the two RW wells (Table A2-2). The CTD-Diver down-hole loggers were removed from the IW wells in readiness for injection to begin in September 2008. Subsequently groundwater was sampled from the RW wells in February and March 2009 after recovery from those wells had begun.

In general, the ambient groundwater of the T2 aquifer is brackish and low in oxygen and nutrients. The quality of the groundwater within the aquifer prior to injection of stormwater does not meet the Australian Drinking Water Guidelines for a number of parameters. The ambient groundwater exceeds the health based guideline value for arsenic and the aesthetic guideline values for dissolved oxygen, total dissolved solids, turbidity, true colour, sulfate, chloride, sodium and iron.

Groundwater sampled from the RW wells during the recovery phase in March 2009 (Table A2-3) was above the Australian Drinking Water Guidelines for iron and turbidity.

3.6. Assessment of aquifer treatment

The potential for water quality changes due to hydrogeochemical processes can be assessed to evaluate any treatment or degradation during aquifer storage and transfer. Equilibrium modelling was used to predict the major influences on water quality in the aquifer (Appendix 6).

The aquifer storage and transfer component of the ASTR trial has been predominantly operating in aquifer flushing mode, designed to ensure the salinity of the recovered water meets water quality target values (Kremer et al. 2008).

Despite being in the early stages of the subsurface component of the ASTR trial, the available groundwater monitoring data can be used to understand water quality changes as outlined below:

• IW wells during the flushing phase can be used to examine water quality changes after aquifer passage.

• RW wells during the flushing, injection and storage phases are indicative of effects on water quality caused by accumulation of nutrients in the immediate vicinity of injection wells.

• RW wells during the recovery phase provide information on the quality of recovered water after aquifer storage and transfer.


3.7. Sampling and analysis summary

Water quality samples taken from the Parafield stormwater harvesting system and the ASTR well-field were analysed at various laboratories as shown in Table 5. Sample preservation and storage were undertaken according to the Standard Methods for the Examination of Water and Wastewater (APHA-AWWA-WEF 2005).

Table 5 List of laboratories that performed analyses for the ASTR project, 2006-2009

Australian Water Quality Centre has quality system certification under ISO 9001, and NATA technical competence under ISO 17025 and NATA accreditation 1115 for chemical and biological analyses. Western Radiation Services has NATA technical competence under ISO 17025 and NATA accreditation 14174 for radiological analyses. National Measurement Institute has quality system certification under ISO 9001, and NATA technical competence

Group Analyte Laboratory

Electrical

conductivity

pH

Dissolved oxygen

Temperature

Physico-chemical

Redox potential

Field measurement

Electrical

conductivity

pH

Suspended solids

Turbidity

Physico-chemical

True Colour

Australian Water Quality Centre, Bolivar, SA

Major ions All analysed Australian Water Quality Centre, Bolivar, SA

Metals All analysed Australian Water Quality Centre, Bolivar, SA

Nutrients All analysed Australian Water Quality Centre, Bolivar, SA

Thermotolerant

coliforms

E. coli

Enterococci

Sulfite reducing

Clostridia

Giardia

Faecal Streptococci

Australian Water Quality Centre, Bolivar, SA

Clostridium spores

Campylobacter

Cryptosporidium

Australian Water Quality Centre, Bolivar, SA or

CSIRO Land and Water, St Lucia, QLD

F-specific phage

Somatic phage CSIRO Land and Water, St Lucia, QLD

Microbiology

Enteric virus CSIRO Land and Water, Floreat, WA

Faecal sterols All analysed Australian Water Quality Centre, Bolivar, SA

Trihalomethanes

formation potential All analysed Australian Water Quality Centre, Bolivar, SA

Haloacetic acid formation potential

All analysed Australian Water Quality Centre, Bolivar, SA

Radiological All analysed Western Radiation Services, Welshpool, WA

All analysed National Measurement Institute, Pymble, NSW

Organic chemicals Nitrosamines and

pharmaceuticals

Forensic and Scientific Services, Coopers Plains,

QLD


under ISO 17025 and NATA accreditation 198 for chemical analyses. Forensic and Scientific Services has quality system certification under ISO 9001 and NATA technical competence under ISO 17025 and NATA accreditation 41 for chemical analyses.

4. HAZARDS IN THE STORMWATER HARVESTING SYSTEM

This section addresses six water quality hazards in source water identified in the draft Managed Aquifer Recharge Guidelines (pathogens, inorganic chemicals, salinity, nutrients, organic chemicals and turbidity), drawing on data reported in Section 0 and documented in Appendices 1 and 3.

4.1. Pathogen numbers in the source water

Over the period 2006–2008 there were faecal indicators (thermotolerant coliforms, E. coli, Faecal Streptococci and Faecal Enterococci) detected at the cleansing reedbed inlet (WE1) and outlet (WE2) (Appendix 1). The Australian Drinking Water Guidelines state that faecal indicators should not be detected. These faecal indicators are likely to have their origin from the warm blooded fauna within the system.

The cleansing reedbed system is able to reduce faecal indicator numbers with variable removal efficiencies (Average RE 0.55 – 0.84 depending upon the indicator). These are lower than those previously reported by Page et al. (2008) with differences due to the variability of the inputs. The reedbed treatment has a variable efficacy as a barrier to indicator organisms but most pathogens are not anticipated to survive the subsurface treatment barrier.

As described by Page et al. (2008) pathogen removal efficiencies can be classed as either physical, chemical or biological. One of the mechanisms for removal of pathogens is thought to be predation by indigenous micro-organisms in the reedbed (Toze et al. 2008). Controlled experimentation into pathogen removal was performed with the use of pathogen diffusion chambers to assess die-off rates (Toze et al. 2008).

Cryptosporidium, Campylobacter and Clostridium spores were sampled for in 2007 and 2008. Cryptosporidium was not detected; Campylobacter was detected once at both the reedbed inlet and outlet in 2007; and Clostridium spores were frequently detected at both the reedbed inlet and outlet, with a maximum count of >1,000 cfu/L. Enteric viruses (which includes rotavirus) were not detected when sampled for in 2008.

Faecal sterols, such as coprostanol, are produced in the digestive tract of humans by microbial hydrogenation of cholesterol. By exploiting the differences in the sterol profiles of humans and animals, it is possible to determine the source of the faecal contamination. The most abundant faecal sterol, coprostanol, has been detected in the majority of surface waters and sediments contaminated with sewage. The presence of coprostanol is primarily a consequence of anthropogenic input into a system and hence represents the presence of sewage contamination. Coprostanol was detected and had a maximum concentration of 140 ng/L at the cleansing reedbed inlet.

The coprostanol / epicoprostanol index is used to differentiate between human and non-human faecal inputs (Leeming et al. 1996). Studies by Nichols et al. (1996) confirmed values of >0.7 as indicative of urban sewage pollution and concluded that this ratio is a very useful tool for the elucidation of sources of faecal pollution. Faecal sterol data in Appendix 1 does not permit the accurate determination of ratios as coprostanol or epi-coprostanol or both were not detected in samples, indicating an overall low level of faecal contamination. Presence of cholestanol at a maximum concentration up to 450 ng/L indicates the presence of diffuse non-human faecal pollution, coming from sources such as the fauna present in the reedbed or runoff from the urban catchment. Based on the low concentrations of faecal sterols detected the primary sources of faecal contamination to the stormwater was unlikely


to be from human sources and further corroborates that the presence of human derived pathogens in the stormwater is likely to be low.

The risks from pathogens to human health are further discussed in Section 6.1.

4.2. Inorganic chemicals in the source water

New infrastructure built in 2008 included an above ground storage tank for direct recovery of ASR water which now no longer passes through the cleansing reedbed. This has lead to changes in the quantities of hardness, magnesium and calcium passing through the cleansing reedbed, though levels never exceeded the Australian Drinking Water Guidelines. All inorganic chemicals at both the cleansing reedbed inlet (WE1) and outlet (WE2) remained below the Australian Drinking Water Guidelines with the exception of iron.

Maximum measured total iron concentrations reached 1.2 mg/L at the outlet, with 79% of samples exceeding the Australian Drinking Water Guideline of 0.3 mg/L. High iron in the system has been previously identified by Page et al. (2008) who concluded that it was released from sediments within the Parafield stormwater harvesting system as a result of rain events.

Page et al. (2008) reviewed reported studies on the removal of heavy metals by urban wetlands. The average REs for the cleansing reedbed for lead (0.72) and zinc (0.56), the two most commonly reported metals, are very similar to the average reported in the literature. Other metals such as iron and manganese had at times higher dissolved and total concentrations exiting the reedbed than in the raw stormwater samples (total iron average RE = -0.16; total manganese REs = -0.80). High iron concentrations in the reedbed-treated water can be a potential risk and are further discussed in Section 6.2.

Given the large quantities of iron and manganese that wash into and then out of the system, there will always be a significant source of iron present in the sediments of the Parafield stormwater harvesting system available for release. Additional treatment provided during subsurface storage is evaluated in Section 5.2 and the risks from inorganic chemicals are assessed in Section 6.2

4.3. Salinity of the source water

Salinity was within the Australian Drinking Water Guidelines for the reedbed-treated water throughout the entire period of the water quality monitoring (Table A1-1). Salinity should be unaffected by the reedbed treatment as it acts conservatively through the system (Page et al. 2008). The reported average RE for conductivity, TDS and chloride were -0.15, -0.16 and -0.02 respectively. That these REs are negative infers production of salinity within the system caused by evaporation from the reedbed and occasional ingress of saline shallow groundwater into the in-stream basin.

The risks from salinity are further discussed in Section 6.3.

4.4. Nutrients in the source water

Nutrient concentrations at the reedbed inlet (WE1) and outlet (WE2) were all below the Australian Drinking Water Guidelines.

Nutrient removal in wetlands has been extensively studied and have been summarised by Page et al. (2008). The cleansing reedbed had similar REs for nitrogen and phosphorous to the REs previously reported by Marks et al. (2005) and Page et al. (2008). Organic carbon removals in the reedbed were much lower than previously reported by Page et al. (2008) but typical for biofiltration systems (Page et al. 2006). High nutrient concentrations in the


reedbed-treated water can be a potential operational risk and may facilitate well bio-clogging and are discussed in Section 6.4.

4.5. Organic chemicals in the source water

A comprehensive suite of organic chemicals was monitored within the inlet and outlet of the cleansing reedbed. These included herbicides, pesticides, hydrocarbons, poly aromatic hydrocarbons (PAH), detergents, industrial solvents, pharmaceuticals and personal care products. Of these, the herbicide simazine was the most frequently detected organic chemical in the source water but has never exceeded the Australian Drinking Water Guidelines value of 20 µg/L. A small number of organic chemicals were detected at least once in grab samples and via the targeted composite water quality monitoring in 2007 and 2008 (Table A1-1 and Table A1-2). Passive samplers deployed in 2006 and 2007 detected trace (ng/L) levels of organic chemicals, but again these were below the Australian Drinking Water Guideline values (Table A1-1). A list of the organic chemicals monitored but not detected is given in Table A3-1. The organic chemicals detected in 2006-2008 form the basis of future water quality monitoring (Appendix 4).

The removal efficiencies for organic chemical hazards with grab sampling could not be calculated (due to the low number of detections) for the ASTR system. A preliminary attempt to calculate the removal efficiencies in the reedbed for 2007 using passive samplers by Page et al. (in prep) resulted in simazine REs between 0.44-0.59, diuron REs between 0.42-0.51 and atrazine REs of between 0.49-0.63 depending upon the method used for the calculation. The risks from organic chemicals are further discussed in Section 6.5.

4.6. Turbidity in the source water

Turbidity was generally low at the reedbed outlet (WE2), but 24% of 34 samples still exceeded the Australian Drinking Water Guidelines of 5 NTU. High turbidity is not a direct risk to human health, though high turbidity may interfere with the efficacy of disinfection, and may contribute to clogging of injection wells.

The ASTR pre-treatment system has a reasonable average RE for suspended solids (0.73) and turbidity (0.77) similar to that previously reported in literature. But additional sources of turbidity exist within the reedbed (e.g. algae, particles) that prevent a much lower turbidity being reached by this barrier.

During the period 2006–2008 there were only small changes to the median particle size, with 126 µm at the reedbed inlet (WE1) dropping to 86 µm at the outlet (WE2). High turbidity concentrations and large particle sizes in the reedbed-treated water can be a potential hazard and cause physical well clogging.

The risks from turbidity are further discussed in Section 6.6.


5. HAZARDS IN THE AQUIFER SYSTEM

The same six water quality hazards are also evaluated for groundwater, both in its native state, and during flushing as well as on recovery. This section draws on data summarised in Section 3.5 and in Appendix 2.

5.1. Pathogens in the groundwater

Prior to introduction of harvested stormwater into the aquifer, Enterococci, Streptococci and E. coli were not present in the ambient groundwater. During the flushing and injection phases Enterococci, Streptococci and E. coli were detected in one out of twenty-two (5%) groundwater samples collected in 2007 and 2008, at 1 cfu/100 mL. There were no detections of Enterococci, Streptococci and E. coli in the groundwater collected from the RW wells in 2008-2009.

Microbial pathogens lose viability in groundwater and their survival is influenced by the pathogen type, source water type, temperature, redox conditions, activity of indigenous groundwater microorganisms and aquifer geochemistry (Dillon and Toze 2005). Pathogen decay in the T2 aquifer has been previously illustrated to reduce the risk associated with recycling wastewater via Aquifer Storage and Recovery (Toze and Hanna 2002).

Controlled experimentation was performed with the use of pathogen diffusion chambers to assess die-off rates under the conditions within the T2 aquifer (Toze et al. 2009). Rapid decay was evident for Campylobacter with a 1-log10 removal time (T90) of less than 1 day. Cryptosporidium and rotavirus die-off was slower with T90 values exceeding the 40 day duration of the pathogen attenuation tests. The pathogen die-off rates measured in the T2 aquifer were used within the revised quantitative microbial risk assessment (Appendix 5). The risks from pathogens to human health are further discussed in Section 6.1.

5.2. Inorganic chemicals in the groundwater

The concentrations of arsenic, chloride, iron, sodium and sulfate in the ambient groundwater are above the Australian Drinking Water Guideline values. This will affect the recovered water quality if mixing between the source water and the ambient groundwater leads to recovery of a significant component of ambient groundwater. The concentration of arsenic, chloride, sodium and sulfate in the groundwater was reduced to acceptable levels during the flushing and injection phases, due to the lower concentrations present within the source water.

Hydrogeochemical reactions are important influences on the quality of water that is recovered from a Managed Aquifer Recharge (MAR) scheme. The chemistry of the water stored in an aquifer is affected by the quality of the source water, the conditions within the aquifer and chemical reactions between the source water and the aquifer material or the ambient groundwater (EPHC–NHMRC–NRMMC 2008a). As a result, the aquifer can both treat and degrade water quality (Dillon and Toze 2005).

Changes to the major ion chemistry of the source water resulted from mineral equilibrium, redox processes and ion exchange processes (Appendix 6). Increased concentrations of calcium and magnesium were due to dissolution of carbonate minerals while bicarbonate was added through carbonate mineral dissolution and organic matter oxidation (Vanderzalm et al. 2006). Carbonate dissolution will continue to occur when the source water injected into the aquifer is not in equilibrium with the dominant carbonate minerals (e.g. WE2). While ion exchange released sodium from exchange sites in exchange for calcium, sodium concentrations remained below the Australian Drinking Water Guidelines value.

Redox processes are important influences on water quality and can vary both spatially and temporally in the aquifer storage zone. This was illustrated by the behaviour of iron in the IW


and RW wells. Removal was evident in groundwater from IW1 during injection (September 2008) and RW1 during recovery (March 2009), with iron concentrations 0.2-0.3 mg/L lower than expected from conservative mixing between the source and receiving waters which is likely to achieved by precipitation of insoluble iron oxides. Despite this removal, iron concentrations in the groundwater within the ASTR storage zone remained greater than the Australian Drinking Water Guideline value of 0.3 mg/L. In contrast, a localised increase of approximately 5 mg/L iron was evident around the RW wells following their use for injection in the flushing phase, believed to be due to reductive dissolution of iron oxides. Some localised removal of sulfate was also evident in the vicinity of the RW wells during aquifer storage (February 2009) with sulfate concentrations below those in the ambient groundwater and source water.

The risks from inorganic chemical hazards are assessed in Section 6.2.

5.3. Salinity of the groundwater

The ambient groundwater in the T2 aquifer is brackish, with a total dissolved solid (TDS) concentration of approximately 2,000 mg/L (EC ~3,600 µS/cm) measured in groundwater in May 2006 at the ASTR site. Freshening of the groundwater during the flushing phase resulted in a decline in TDS in the IW wells to 1,350 mg/L in 2007 and 325 mg/L in 2008. The RW wells were fresher with a TDS of approximately 200 mg/L. Mixing between the source water and the ambient groundwater and the implications for the salinity of the recovered water and recovery efficiency is discussed in Section 6.3.

As the ASTR scheme involves injection of fresh water within a brackish aquifer, mixing between the source water and the ambient groundwater occurs within the storage area and leads to an increase of the salinity of the injected water. To ensure the salinity of the recovered water remains low when the injection/extraction cycle occurs, the study area was flushed with source water injected through the inner RW wells to create a fresh plume and therefore reduce the mixing between the fresh injected water and the brackish groundwater. In effect, the flushing stage is an aquifer treatment step to ensure that a fresh plume develops within the storage zone which is necessary to ensure the salinity of the recovered water is suitable as a drinking water supply.

Assessment of the flushing stage was made using salinity monitoring at the four IW wells from September 2006 to August 2008 while injecting through the two inner RW wells. EC data collected either during sampling or profiling at the IW wells clearly shows a breakthrough of injectant within the aquifer with a decline in EC from 3,620 µS/cm in June 2006 to 591 µS/cm in August 2008 (Figure 6). No significant increase in EC occurred during storage intervals between injection events (white areas on Figure 6) suggesting that no ambient groundwater is likely to remain in the less permeable parts of the aquifer due to adequate flushing of the aquifer.

The risks from salinity and sodicity are covered in Section 6.3.


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IW1 sampling IW2 sampling IW3 sampling IW4 sampling

IW1 profile IW2 profile IW3 profile IW4 profile

Injection in RWInjection in RW Injection in RW

Figure 6 Time versus depth-average EC data obtained from down-hole profiles over the opened intervals, and EC data collected during sampling, at the observation wells IW1, IW2, IW3 and IW4 during the flushing phase from September 2006 to August 2008, showing the breakthrough of source water in the aquifer. Injection periods at the RW wells are shown with grey shading.

5.4. Nutrients in the groundwater

The nutrient status of the ambient groundwater is low, and nutrient concentrations in native groundwater met Australian Drinking Water Guidelines.

During the flushing phase, removal of organic carbon, nitrogen and phosphorus was evident between the RW and IW wells (Appendix 6). The TOC concentration at IW1 in September 2008 (end of flushing phase) was approximately 50% lower than expected from conservative mixing between the source and receiving waters, while total nitrogen and phosphorus reduction was ~70%. The impact of injection into the RW wells is evident during storage and in the first recovery from these wells through increased dissolved organic carbon (DOC), nitrogen (predominantly in the form of ammonia) and phosphorus. These wells had received the greatest flux of nutrients which can accumulate around the point of injection. This is most evident in groundwater sampled from the RW wells in February 2009 within a day of the first recovery of water, where DOC reached 9.8 mg/L and ammonia (6.0 mg/L) and phosphorus (0.2 mg/L) concentrations were greater than measured in the WE2 source water. Subsequent sampling from the RW wells in March 2009 showed DOC, ammonia and phosphorus concentrations had dropped to 4.2, 0.2 and 0.035 mg/L respectively. These values are more representative of the quality of recovered water during ongoing operation.

The risks from nutrients are further discussed in Section 6.4.

5.5. Organic chemicals in the groundwater

A list of organic chemicals monitored for but not detected is given in Appendix 3. There has been little evidence for the presence of organic chemicals in the groundwater despite an extensive monitoring suite. Detergents were identified in the RW wells in February 2009. There was a single detection of 2,6-dichlorophenol in IW3 in 2008. This was thought to be caused by solvent residuals from the construction of the well. Simazine was not detected in


the IW or RW wells despite being the most frequently detected organic chemical in the source water, suggesting sorption or biodegradation during aquifer storage.

Subsurface storage can potentially provide a treatment step for organic chemicals. In addition aquifer passage through varying redox zones can provide exposure to the conditions required for degradation of multiple organic chemical hazards. Simazine has been reported to degrade in aerobic aquifers with a mean half-life of 60 days (ranging from 10–300 days) (EPHC–NHMRC–NRMMC 2008a). However there is no data on simazine degradation rates in anaerobic aquifers. As a result, a laboratory degradation study using aquifer material and groundwater from the ASTR site will be undertaken to assess the simazine degradation rate under anaerobic conditions comparable to those found in the T2 aquifer (Dillon et al. 2009b).

The risks from organic chemical hazards are further discussed in Section 6.5.

5.6. Turbidity in the groundwater

Turbidity and particulates can be removed by filtration in the aquifer. However particulate hazards can also be generated from mineral dissolution and particle mobilisation within the storage zone during pumping, which may lead to turbidity values above the Australian Drinking Water Guidelines. The turbidity of the groundwater from the IW wells during the flushing phase varied between 3.9 - 22 NTU in 2007 and 1.5 - 3.1 NTU in 2008 (Appendix 2), suggesting a reduction in turbidity with time. The initial water recovered from RW1 (March 2009) was also low in turbidity (1.2 NTU). However insufficient data for the recovered water quality and the variability in turbidity measured within groundwater samples makes it difficult to fully assess the capacity of the aquifer as a treatment step for turbidity and particulates.

The risks from turbidity and particulates are assessed in Section 6.6.


6. RISK ASSESSMENT

6.1. Pathogens

Urban stormwater can potentially contain a wide range of pathogenic hazards that pose risks to human health. The principal source of human pathogens is from sewer leaks and pumping station overflows to the stormwater system. The maximal risk assessment considers the quality of the untreated stormwater entering the cleansing reedbed (WE1), data provided in Appendix 1. The maximal risk assessment indicates that the risks are unacceptable due to the presence of faecal indicator organisms in the untreated stormwater. The microbiological water quality monitoring (Appendix 1) indicated that although faecal indicator organisms (thermotolerant coliforms; E. coli; Enterococci; Streptococci) were frequently detected in low numbers in the source water, there were never any pathogenic organisms detected. Nevertheless with the presence of faecal indicator organisms the potential risk of pathogenic hazards cannot be ruled out.

In managing the residual pathogenic risks potentially present in stormwater it is necessary to determine tolerable risk. The Australian Guidelines adopt the use of disability adjusted life years (DALYs) to convert the likelihood of infection or illness into burdens of disease, and sets a tolerable risk as 10–6 DALYs per person per year (EPHC–NHMRC–NRMMC 2008b). The tolerable risk is then used to set health-based targets that, if met, will ensure that the risk remains below 10–6 DALYs per person per year.

In identifying hazards, it is impractical to set human health-based targets for all microorganisms that might be present in the source stormwater; therefore, the MAR Guidelines specify the use of reference pathogens instead – Campylobacter for bacteria, rotavirus and adenovirus for viruses, and Cryptosporidium parvum for protozoa and helminths. Dose–response information obtained from investigations of outbreaks or experimental human-feeding studies can be used to determine how exposure to a particular dose of a hazard relates to incidence or likelihood of illness (EPHC–NHMRC–NRMMC 2008a). A Quantitative Microbial Risk Assessment (QMRA) of these reference pathogens was further developed based on the models used by Page et al. (2008) but incorporating the use of pathogen decay chamber studies (Toze et al. 2008; 2009) to describe the decay in the reedbed and aquifer and is presented in Appendix 5. The revised QMRA model also incorporates revised pathogen numbers in the source water (based on Draft Australian Guidelines for Water Recycling 2B Stormwater Harvesting and Reuse) and includes post-recovery treatment by UV disinfection (as proposed by Toze et al. 2009) and chlorination prior to supply to the mains, so as not to reduce the chlorine residual in the mains.

Results of the QMRA are shown in Figure 7 with the dotted line indicating the acceptable

risk. Residual bacterial risks, were << 1 × 10-10 DALYs and from protozoan and viral hazards

of 2.8 × 10-8 and 3.0 × 10-7 DALYs per person per year respectively. The QMRA indicates that residual risks are acceptable for each of the reference pathogens if all the barriers are in place.


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Figure 7 DALYs as a function of the multiple barriers of the ASTR scheme (dotted line indicates ‘tolerable risk’ set at 10

–6 DALYs per person per year)

Further discussion of the pathogen risks is given in Section 7.1.

Pathogen numbers could be reduced to further decrease the risk using various other treatment processes, either singly or in combination such as UV-disinfection and chlorination. The Australian Guidelines for Water Recycling (NRMMC–EPHC–AHMC 2006) gives summaries of treatment measures for the three reference pathogens that can be applied to achieve tolerable risk for the ASTR project.

6.2. Inorganic chemicals

Inorganic chemical hazards in the ASTR scheme can be present within the source water, the receiving groundwater or can arise from reactions with the aquifer minerals. The maximal risk assessment indicates that only iron in the untreated stormwater (section 4.2) and arsenic, chloride, iron, sodium and sulfate in the ambient groundwater (section 5.2) have been identified as unacceptable risks

The residual risk assessment includes the cleansing reedbed and aquifer as barriers but also as potential hazard sources in the system. The concentration of iron leaving the reedbed (WE2 – Table A1-2) is in soluble and particulate forms and thus precipitation and filtration can reduce the iron concentration following injection into the aquifer. The reedbed-treated urban stormwater is over-saturated with respect to iron oxides and therefore precipitation of insoluble oxides is expected (Appendix 6). Filtration and precipitation will occur near to the injection well and could result in well clogging.

Residual inorganic chemical risks within the receiving groundwater can be managed by minimising the amount of ambient groundwater that is recovered. At the ASTR site mixing between the ambient groundwater and the source water is minimised in order to meet the salinity requirements for the recovered water (section 6.3).

The key residual risks associated with inorganic chemical hazards during MAR arise from subsurface reactions. These reactions could lead to increased concentrations of arsenic, iron, manganese, traces species (e.g. cadmium, chromium, lead), or hydrogen sulfide in the


recovered water. The aquifer sediments provide a potential source from which inorganic chemicals could be mobilised into the recovered water.

While there was some removal of iron evident during aquifer storage and transfer (Section 5.2), the iron concentration in groundwater within the ASTR storage zone remained above the Australian Drinking Water Guideline Value of 0.3 mg/L (aesthetic guideline). The iron concentration in IW1 at the end of the flushing phase was 0.36 mg/L, comparable to 0.38 mg/L in RW1 during recovery (March 2009; 16 ML recovered from RW1). As these samples are considered to be representative of the quality of recovered water during ongoing operation, the recovered water quality from the ASTR scheme is likely to marginally exceed the aesthetic guideline value.

The arsenic concentration in the ambient groundwater (9–11 µg/L) is sufficient to indicate a source of arsenic within the aquifer sediments that can lead to increased concentrations through MAR. Such arsenic mobilisation was observed at the nearby Bolivar ASR scheme also in the T2 aquifer (Vanderzalm et al. 2007).

There is potential for arsenic mobilisation during aquifer storage via two possible mechanisms; the oxidation of pyrite or the reductive dissolution of iron oxides (Appendix 6). Arsenic was quantified in aquifer core samples at concentrations of 6 - 144 ppm and was present in samples containing iron in oxidised forms (hematite and goethite) and reduced forms (pyrite and siderite).

Preliminary results for the arsenic concentration in the vicinity of the RW during the first recovery since injection into these wells do not substantiate the estimate of unacceptable residual risk through arsenic mobilisation (Appendix 6). Insufficient injection via the IW wells has occurred to understand the reactions impacting on water quality during a true ASTR operation. Previous investigations during ASR using reclaimed wastewater at the Bolivar site indicate the reaction processes and water quality around the point of injection are not representative of the water quality within the bulk of the storage zone (Vanderzalm et al. 2006).

Cadmium, chromium, lead and nickel concentrations in the ambient groundwater were predominantly below the limit of detection while zinc was measured at low concentrations (Table A2-2). The content of cadmium, lead, nickel and zinc within the sediments is low, while chromium is present at concentrations ranging from 34 - 128 ppm. The recovered water quality from the RW wells did not indicate mobilisation of these trace species during aquifer storage.

The results to date indicate that the risk is not well defined for arsenic, but is unacceptable for iron based on the aesthetic water quality guideline value. Risks for other inorganic chemicals are considered acceptable. Further discussion of these risks is given in Section 7.2.

Reducing the organic matter content of the reedbed-treated source water (WE2 – Table A1-2) will control the amount of reductive iron dissolution that occurs in the subsurface. Post-treatment for the recovered water may include oxygenation (e.g. during mixing in Parafield storage tanks) to allow iron oxides to form and settle, while also providing a suitable surface to scavenge trace species such as arsenic from solution through sorption. The effectiveness of this barrier has yet to be assessed.

6.3. Salinity / sodicity

Salinity can be a risk to public health and the environment, if salinity values exceed the 500 mg/L aesthetic drinking water guideline for total dissolved solids (TDS). Salinity and sodicity also have effects on soil structure, plant growth and agricultural production when recovered water is used as irrigation water.

For the maximal risk assessment the salinity was monitored using electrical conductivity (EC) and total dissolved solids (TDS) as described in Section 4.3 and data given in Appendix 1.


Sodicity which represents the proportion of sodium concentration relative to calcium and magnesium concentrations can be expressed using the sodium adsorption ratio (SAR) (ANZECC–ARMCANZ 2000). The maximal risk assessment indicates that the risks from salinity and sodicity are currently acceptable. The SARs of the injected water, and recovered water at the end of the flushing phase, are respectively 0.95 and 0.45. Therefore, sodicity effects are unlikely to occur while using the recovered water for irrigation or gardening purposes.

For the residual risk assessment, monitoring of the ASTR wells during the flushing phase showed that the aquifer was effectively flushed (Section 5.3) with the IW wells reaching an 85% fraction of source water in August 2008 after 377 ML of water had been recharged through the inner wells RW1 and RW2. Predictive modelling based on field data suggests that sufficient water has been injected through the inner RW wells to ensure the salinity of the recovered water remains below 500 mg/L TDS during the next nine years of injection/recovery cycles operating with a recovery efficiency of 80% (Kremer et al. 2008). Recovery efficiency is defined as the ratio between the volume of extracted water at acceptable quality and the volume of injected water during an injection / extraction cycle.

The higher conductivity part of the T2 aquifer (T2c), situated a few metres below the open intervals of the ASTR wells, is likely to induce vertical flow and exchange between the storage area created during the flushing phase, and T2c, which has not been flushed. Additional mixing between the fresh water from the storage plume and the brackish water from T2c is likely to increase the salinity of the recovered water. EC measurements from the deepest piezometer, P2, clearly showed a freshening of the T2c with EC values dropping from 1,690 µS/cm in August 2008 to 1,380µS/cm in January 2009 due to injection at the ASTR site. Predictive modelling taking into account the exchange with the higher conductivity layer within T2c suggests that enough flushing of the aquifer has occurred to sustain quality of the recovered water below 500 mg/L TDS despite mixing with T2c (Kremer et al. 2008).

Residual risks of salinity and sodicity in ASTR are acceptable as long as mixing with native groundwater is effectively managed.

Preventive measures to reduce salinity and sodicity hazards are:

• Design of the well field, determination of operational variables and preventive flushing of the aquifer

• Monitoring of the salinity of the injected water (maintain below 500mg/L TDS)

• Monitoring of the salinity of the recovered water

• Calibration and validation of solute transport model to predict mixing and residence time for operational scenarios.

6.4. Nutrients

The maximal risk assessment for nutrients in the untreated stormwater (WE1 – Appendix 1) indicates that the risks to human health are all acceptable. However for the environmental risk assessment the untreated stormwater is higher in nutrients than the receiving groundwater. In addition the nutrient levels present in the source water may vary considerably, due to changing loads from the catchment and variability in the treatment provided within the cleansing reedbed.

After reedbed treatment the nutrient concentrations are all of an acceptable residual risk for drinking water and ecosystem support (as per Section 6.11). However, the dissolved organic matter within the source water stimulates microbial activity and the resultant redox processes impact on the concentrations of nutrients and other inorganic chemicals (as discussed for iron and arsenic in Section 6.2). This has resulted in the high nutrient concentrations observed in the RW wells in 2008–2009 due to mineralisation of organic matter which had accumulated around the wells during injection via these wells. These RW samples represent


a nutrient rich zone in the immediate vicinity of the well during recharge and storage phases and do not represent the quality within the bulk of the storage zone, nor the quality of recovered water (as discussed for iron in Section 6.2).

The groundwater quality data for the IW wells during the flushing phase suggests there is nutrient removal observed along the injection flow-path. However insufficient groundwater quality data is available to validate the nutrient removal processes in the subsurface for the ASTR scheme.

Given that none of the nutrients in the source water exceed any of the Australian Drinking Water Guideline values the residual risk from nutrients to human health and the environment are considered acceptable. Furthermore, the organic carbon content of the source water is not expected to produce excessive microbial clogging in the limestone aquifer.

6.5. Organic chemicals

Catchment hazard analysis identified organic chemicals as potential hazards within the source water, originating from the current residential, commercial and industrial land uses in the catchment (Swierc et al. 2005). Organic chemical hazards include urban and residential application of pesticides and herbicides; and chemical and fuel/hydrocarbon storage, use transportation and potential spills. Given the varied nature of industry and businesses within the catchment area, including general retail, wool processing and the automotive based industry, there are a large number of potential organic chemical hazards. The maximal risk assessment indicates that for the organic chemicals monitored either they were not detected (Appendix 3) or detected below the current guideline value (Appendix 1, as determined by the methods from the Augmentation of Drinking Water Supplies Guidelines (EPHC–NHMRC–NRMMC 2008b)).

For the residual risk assessment an extensive suite of organic chemicals was analysed within composite samples of the source water to reduce the uncertainty regarding their presence or absence and assess the risk posed to human health (Appendix 3). In addition, passive samplers were employed to evaluate the time weighted average concentration of selected organic chemicals over the 1 week to 1 month period of deployment. Passive samplers have lower detection limits than conventional methods for analysis of water samples and overcome the problem of detecting intermittent spikes in grab samples (Page et al. 2008).

Sediment sampling undertaken within the Parafield stormwater harvesting system reported a decline in total petroleum hydrocarbons (TPH) moving from the sediments of the in-stream basin to the holding storage and the cleansing reedbed. However detection limits were not sensitive enough to distinguish between changes in the benzene, toluene, ethylbenzene or xylene (BTEX) or polycyclic aromatic hydrocarbon (PAH) composition in the sediments of the harvesting system (Page et al. 2008). Thus sediment analysis was deemed as too insensitive to quantify removal of organic chemicals through adsorption to sediments.

Detergent as methylene blue active substances (MBAS) was measured in the outlet of the cleansing reedbed in 60% of samples collected (0.05 - 0.10 mg/L) in 2007–2008. These detergents may have a variety of potential sources within the catchment (Page et al. 2008).

Simazine was the most frequently detected organic chemical within the outlet of the cleansing reedbed over a 3 year period. In 2006, simazine was not detected in 5 weekly composite samples (detection limit 0.5 µg/L); in 2007 there were 2 detections from 6 composite samples collected over 7 day intervals, reporting similar concentrations of 0.46 and 0.57 µg/L; and in 2008 there was a single detection of 0.76 µg/L from 4 weekly composite samples and a concentration of 0.32 µg/L in a composite collected over the same 4 week period. Based on the 2007-2008 data, where a lower detection limit of 0.1 µg/L was available, simazine was detected in 30% of samples. A review of herbicide use within the catchment did not identify the use of simazine within the catchment by City of Salisbury, TransAdelaide or the Department for Transport, Energy and Infrastructure, however no


information could be obtained for smaller scale herbicide application (Page et al. 2008). Thus the source of simazine is currently unknown.

The simazine concentrations reported for the outlet of the cleansing reedbed (WE2 – Appendix 1) are considerably lower than the human health guideline value of 20 µg/L. Simazine has an average half-life of 60 days under aerobic conditions, but degradation under anaerobic conditions is currently unknown (EPHC–NHMRC–NRMMC 2008a). Some removal through degradation is expected in the cleansing reedbed (Page et al. in prep), but degradation during aquifer storage is not certain and would need to be monitored in the attenuation zone. Experimental work has commenced to address that gap.

Organic chemical hazards were not expected to originate from the aquifer itself as the groundwater in the confined aquifer is protected from anthropogenic hazards by the overlying lithological units.

Based on all of the existing data, the residual risks from organic chemicals are acceptable. However, despite the apparent low risk from organic chemicals it is important to maintain and develop catchment management to minimise the presence (and risk) of these hazards within the source water. Organic chemical hazards have the potential to be released at concentrations exceeding guideline values in extreme events such as bulk chemical spills. Education/communication programs promote correct use of herbicides, application rates and time of application. Preventive measures currently in place to address this at a catchment level include the EPA licensing agreements and stormwater best practice program (Be Stormwater Smart). Mixing within the reedbed and aquifer are likely to reduce concentrations of chemicals that occur in spikes in stormwater.

6.6. Turbidity / particulates

Turbidity is sometimes used as a surrogate for suspended solids or particulate matter. Turbidity itself does not pose a public health risk but if it is in excess of drinking water guidelines in recovered water (where drinking is an intended end use) it can interfere with disinfection performance, leading to an increased risk to human health from microbial pathogens (Section 6.1). There is also an increased risk of transporting a range of contaminants that can adsorb to particles, such as inorganic chemicals (Section 6.2), nutrients (Section 6.4) and organic chemicals (Section 6.5). The Australian Drinking Water Guideline for turbidity, based on aesthetic considerations, is 5 NTU. If disinfection is required, a turbidity of less than 1 NTU is desirable (NHMRC–NRMMC 2004).

The maximal risk assessment for turbidity and particulates is based on the untreated stormwater quality (WE1 - Appendix 1). The maximal risk assessment indicates that the human health risk for turbidity is currently unacceptable. Furthermore, turbidity and particulates in the source water can impact on pumps and irrigation infrastructure, and cause well clogging. Clogging of aquifer pore spaces through the filtration of suspended solids present in the injected water results in the formation of a low-permeability clogging layer. The rate of clogging depends on the concentration of suspended solids and the hydrologic properties of the aquifer. The turbidity and suspended solids values reported at the reedbed outlet show the source water quality to be moderate, and should lead to a low-moderate rate of physical clogging in the limestone aquifer. The treatment provided by the reedbed is judged to be sufficient such that the risk of physical clogging is low given the mineralogy and geology of the aquifer (Appendix 6).

The levels of turbidity in the IW wells during the second year of flushing (1.5 - 3.1 NTU in 2008) and the initial water recovered (1.2 NTU; RW1 March 2009) were below the drinking water aesthetic guideline of 5 NTU. However, the residual risk for turbidity can not be fully defined without additional evaluation of the capacity of the aquifer as a treatment step for turbidity and particulates.


Turbidity risks can be further reduced using various post recovery treatment processes, either singly or in combination. These may include settling (e.g. during storage in Parafield storage tanks) or filtration.

6.7. Radionuclides

The maximal risk assessment found no hazardous land uses within the stormwater catchment that would lead to radionuclides entering the source water (Swierc et al. 2005). Furthermore the T2 aquifer is considered a low risk lithology, without granitic or coal deposits and low in organic carbon content (<0.5%) (Appendix 6). As such the maximal risk assessment for human health and the environment indicates an acceptable risk.

The residual risk assessment indicates that there is potential for release of radionuclides through geochemical reactions when organic matter present in the source water leads to reductive dissolution of iron oxides in the aquifer sediments (Appendix 6). Substantial amounts of radium can be adsorbed to manganese and iron oxide surfaces and thus radium may be released if the oxides dissolve.

Gross alpha and beta (excluding potassium-40) activity was measured in groundwater sampled from the RW wells in February 2009, where increased concentrations of manganese and iron were thought to be due to reductive manganese and iron oxide dissolution. Both measures of radioactivity remained within the Australian Drinking Water Guideline value of <0.5 Bq/L. These RW samples represent reedbed treated stormwater that has been stored in the aquifer for at least 8 months, which is a sufficient time interval to observe any potential increases in radioactivity due to hydrogeochemical reactions. As the gross alpha and beta (excluding potassium-40) activity remains low, this confirms that the residual risk from radionuclides is considered acceptable.

6.8. Pressure, flow rates, volumes and groundwater levels

Over pressurisation resulting from injection in confined aquifers could lead to overflow of nearby existing wells, failure of poorly completed wells and/or rupturing of the aquitard. Conversely, groundwater pressure reduction induced by extraction can lead to diminished access for nearby groundwater users, consolidation of compressible media and land subsidence.

The maximal risk assessment shows that the ASTR wells have been correctly constructed and cemented, as per the well completion permit (available at https://des.pir.sa.gov.au/page/desHome.html). Pump tests and down-hole profiling were performed at each well to characterise the hydraulic properties of the aquifer and to assess any well interferences, or flow, volume and pressure-related hazards. As such the maximal risk is deemed to be acceptable.

For the residual risk assessment, observations of drawdown in nearby wells during pump testing at the ASTR site indicated that no leakage from or to the overlying aquifer occurred (AGT 2007). Nevertheless, the drawdown at some observation wells showed induced flow from another source during development at ASTR wells with flow rate of 15 L/s. The source is likely to be T2c, the higher hydraulic conductivity unit situated at the bottom of the T2 aquifer, and not intersected by the ASTR wells (Table 2). Flow rates at the ASTR wells should be set to ~5 L/s during injection and ~10 L/s during extraction to limit the impact of the leakage to and from the T2c sub-aquifer. In the vicinity of the existing ASR site wells become artesian seasonally as a result of injection. This artesian zone will not extend to other existing wells as a result of the ASTR operation.

The average injection flow rate observed at the RW1 and RW2 wells during the flushing phase between 2006 and 2008 was 4.9 ± 1.7 L/s. The RW wells have not been redeveloped since flushing operations commenced. Moreover, flow rates were stable or increasing over


time, suggesting that neither clogging nor consolidation, which might have occurred due to re-arrangement of mineral grains under increased stress, had occurred during injection at RW1 and RW2. Injection pressures measured at RW1 and RW2 wells did not exceed 500 kPa. To prevent injection pressure from rupturing the aquitard, the injection pressure should not exceed 15*d kPa, where d is the depth (metres) to the base of the aquitard (EPHC–NHMRC–NRMMC 2008a). The depth of the Munno Para Clay is about 160 m below ground, leading to a maximum allowable injection pressure of 2400 kPa. Therefore, injection pressures at ASTR of ~500 kPa cannot induce over pressurisation and rupturing of the aquitard. Similarly, drawdown will not be capable of dewatering the aquitard so consolidation of compressible media and subsidence is unlikely to occur.

Comparison of water levels in the ASTR wells between May 2006 and January 2007 showed water level fluctuations of approximately 6 metres (AGT 2007), with the water level varying from ~4 to 10 m below ground across the well-field. These water level variations result from a regional hydraulic gradient of about 0.0015 from east to west occurring within the T2 aquifer (Pavelic et al. 2004); and from a strong local gradient induced by the Parafield ASR well scheme situated about 300 m north-east of the study using two injection-extraction wells completed over the entire T2 aquifer. The local gradient can be as high as 0.03, either towards the northeast during extraction or the southwest during injection at the ASR site (Kremer et al. 2008). Despite the transfer of fluid pressure occurring between the Parafield ASR and the ASTR systems, monitoring and background data at the ASTR site suggested that no transfer of fluid constituents occurs (Kremer et al., 2008).

Modelling tools can be used to assess the impacts of injection and extraction flow rates and volumes on pressures and water levels in the T2 aquifer close to the ASTR site. Conceptual models defined in Kremer et al. (2008) showed that an area of 800 m radius, including the Parafield ASR scheme, is likely to be affected by drawdown during operations at the ASTR site; and therefore wells situated within this area can potentially become artesian during injection at the ASTR site. Results from simulation of injection and recovery at the four outer ASTR wells showed a maximum drawdown of less than 10 m within the ASTR site, and less than 4 m at the Parafield ASR site.

Based on groundwater monitoring, modelling and observations from MAR operations in the T2 aquifer, the residual risks are acceptable for pressure, flow rates, volume and water levels for the ASTR project.

Additional information to assist operations to minimise the residual risk include:

• Pump testing and geophysical log to characterise the targeted aquifer

• Groundwater monitoring, such as flow rates and volumes at injection and extraction wells and water level fluctuation in observation wells

• Restrict volume of injection and extraction

• Numerical modelling, e.g. to assess the region likely to become artesian, and volume available for extraction, based on operational history and various future scenarios.

6.9. Contaminant migration through preferential flow paths

Preferential flow paths induced either by fractures or high conductivity layers allow recharged water to travel faster than the average flow rate through the porous media. As a result the residence time in the aquifer is reduced, potentially impacting on the treatment capacity of the aquifer.

For the maximal risk assessment, the target T2 aquifer of the ASTR project was investigated and characterised as a sandy-limestone aquifer known to be heterogeneous with respect to depth. The lithological log and core samples collected from piezometer P2 show no evidence of fractures; despite irregular well diameters observed from calliper logs run at the ASTR wells before the casing was installed. Evidence from pumping tests suggests that the flow is


more likely to be through porous media than through fissures or karstic features. Therefore the maximal risk of contaminant migration in fractures is acceptable.

Further evidence for the residual risk assessment from pump tests and electro magnetic (EM) flow-meter analysis showed higher hydraulic conductivity in the bottom part of the T2 aquifer, suggesting that preferential flow paths would occur if T2c was intercepted by the ASTR wells (Kremer et al. 2008). To avoid low recovery efficiency of the ASTR scheme and shorter travel time within the aquifer, the best system configuration defined in Pavelic et al. (2004) involving six wells opened over the entire T2 aquifer, with inter-well distance of 75 m, was revised into a 50 m-spacing system intersecting only the upper part of the T2 aquifer (details of the modelling process used for the revision are described in Appendix 1 in Kremer et al. 2008). Field observations in T2c and three dimensional flow and solute modelling based on field data suggest that the residual risk of contaminant migration in preferential flow paths induced by higher conductive layers in the heterogeneous T2 aquifer is acceptable.

Preventive measures for contaminant migration in preferential flow paths include additional characterisation of the aquifer using geophysical logs and pump tests.

6.10. Aquifer dissolution and stability

The maximal risk assessment indicates that recharge water (WE2 – Appendix 1) may react with the aquifer matrix material, resulting in dissolution of minerals or reduction in the aquifer’s bulk volume or strength. The reedbed-treated urban stormwater is not in equilibrium with carbonate minerals. Therefore injection of this source water into the T2 aquifer will result in dissolution of carbonate minerals, predominantly calcite (Appendix 6). Source water that has additional treatment such as previous aquifer storage (e.g. from ASR) will be less aggressive toward the aquifer minerals.

Aquifer dissolution may increase the effective diameter of a well, consequently increasing yield, and inhibit chronic clogging problems. However, aquifer dissolution can have many negative effects, including collapse of uncased wells, production of turbid water or water containing a lot of sand, mobilisation of clay particles that may become trapped further within the aquifer matrix and development of preferential flow paths that alter aquifer residence time (Section 6.9).

The impact of aquifer dissolution on the stability of the overlying clay aquitard was considered in the residual risk assessment by assuming that dissolution of a 2 m radius around the injection well would result in stability concern (Appendix 6). With estimated dissolution rates of 0.3 and 0.5 mmol/L, the calculated time required for dissolution of the calcite in a 2 m radius around the open interval of an injection well ranged from 120 to 200 years. This was based on a total annual injection volume of 172 ML/year expected under average rainfall conditions (Kremer et al. 2008), with 43 ML/year injected into each IW well.

These calculations indicate that aquifer dissolution is not a risk to the lifetime of the IW wells and hence the risk for aquifer dissolution and stability is acceptable. However the aquifer dissolution rate needs to be determined in the proximity of the injection wells using the behaviour between IW1 and P1 during an injection phase to confirm this.

At present, there are advantages in maintaining some dissolution to increase well efficiency. In the longer term protective measures such as allowing reedbed treated water to pass over limestone chips before injection could be used as a preventative measure if needed.

6.11. Aquifer and groundwater dependent ecosystems

Managed aquifer recharge can affect groundwater dependent ecosystems such as stygofaunal assemblages, and connected rivers and wetlands by raising or lowering the water table, changing nutrient cycles, and introducing contaminants to the system.


The maximal risk assessment reveals that there are no surface water ecosystems connected to the T2 aquifer. Furthermore, there are unlikely to be populations of stygofauna in the T2 aquifer due to the depth, anoxic conditions and lack of karst features. Previous sampling of a number of T2 wells on the Northern Adelaide Plain has failed to detect stygofauna (pers. comm.. Colin Pitmann, City of Salisbury). Low connection to recharge leads to low nutrient availability, and hence low stygofauna populations (Tomlinson and Boulton 2008). Hence the residual risk to groundwater dependent ecosystems is also deemed to be acceptable.

6.12. Energy and greenhouse gasses

Energy consumption and resultant greenhouse gas emissions contribute to global warming, and as such should be minimised. Energy consumption in the provision of water supplies comes from both the treatment of water and pumping from source to treatment site to end user. Pumping water long distances and against gravity is an energy-intensive process (Kenway et al. 2008). Consequently, for the maximal risk assessment, the sourcing of stormwater close to the MAR site and end users will consume less energy than pumping water from a long distance away.

For the residual risk assessment, consideration of the treatment at ASTR provided by the cleansing reedbed and the aquifer is required compared to other potential sources of water such as the River Murray or desalination of sea water. As the ASTR system currently operates, the only energy required for treatment is to pump the water from the in-stream basin to the holding storage, from the reedbed outlet into the injection wells, and out of the recovery wells. High injection pressures increase the energy consumption, especially if the aquifer becomes artesian (however, the risk of this is low, see section 6.8).

Based on 2008 volume and energy consumption data at the Parafield stormwater harvesting system and ASTR well field, and a recovery efficiency of 90%, the ASTR scheme consumes ~2700 MJ/ML of water produced (including distribution to end users). This compares with the energy cost of water supply from the River Murray and Mount Lofty Ranges catchments with conventional treatment (coagulation, filtration and disinfection) and distribution by SA Water, which varies from 3500 MJ/ML (50% River Murray water) to 6900 MJ/ML (90% River Murray water) (Kenway et al. 2008; SA Water Corporation 2007). Seawater desalination typically consumes more than 14,400 MJ/ML (Kenway et al. 2008). As energy consumed per unit of water produced is less for the ASTR project than current SA Water supplies and desalination, the residual risks from excess energy consumption and greenhouse gas emissions are considered acceptable.

Preventive measures to ensure the risks from energy usage and greenhouse gases are further minimised include use of energy efficient infrastructure and future treatment options and by minimising pumping requirements.

6.13. Risk assessment summary

The risk assessment is presented in the order of the twelve hazards outlined in the draft MAR guidelines (EPHC–NHMRC–NRMMC 2008a). Initially a semi-quantitative risk assessment was performed for each of the hazards for human health and environmental endpoints. Table 6 summarises the maximal risk assessment for the twelve key hazards for the human and environmental end points, with green and red indicating acceptable and unacceptable risks respectively. The white boxes indicate that that hazard does not apply to that endpoint (hazards 8 to 12 for the human endpoint).


Table 6 Maximal risk assessment summary

End points MAR Hazards

Human Environmental

1. Pathogens Unacceptable Acceptable

2. Inorganic chemicals Unacceptable Unacceptable

3. Salinity and sodicity Acceptable Acceptable

4. Nutrients: nitrogen, phosphorous and organic carbon Acceptable Unacceptable

5. Organic chemicals Unacceptable Unacceptable

6. Turbidity and particulates Unacceptable Unacceptable

7. Radionuclides Acceptable Acceptable

8. Pressure, flow rates, volumes and groundwater levels Unacceptable

9. Contaminant migration in fractured rock and karstic aquifers Unacceptable

10. Aquifer dissolution and stability of well and aquitard Unacceptable

11. Aquifer and groundwater-dependent ecosystems Acceptable

12. Energy and greenhouse gas considerations Acceptable

In Table 6 for hazards 1 to 7, for the human health end point the Australian Drinking Water Guideline values were compared to the water quality data (untreated stormwater at WE1) from Appendix 1. For hazards 1 to 11 for the environmental endpoint, the aquifer’s beneficial use was conservatively assumed to be for irrigation supplies (even though the salinity of the groundwater would not support irrigation). For each hazard where the mean exceeded the water quality guideline the risk was deemed unacceptable (labelled red) and where it was below it was labelled green. For hazard 12, energy and greenhouse gas considerations the environmental endpoint used was the biosphere. Assessment of this hazard differed slightly in that a comparative risk assessment was performed. The energy consumption per ML of water produced by ASTR was compared to the current energy consumption per ML of water to supply drinking water to Adelaide.

Table 7 summarises the results of the semi-quantitative residual risk assessment for the ASTR system using the same approach as for the maximal risk assessment but with inclusion of all the barriers: source control; reedbed treatment; aquifer treatment; UV disinfection, chlorination and an aeration tank (iron removal).

Table 7 Residual risk assessment summary

End points MAR Hazards

Human Environmental

1. Pathogens Acceptable Acceptable

2. Inorganic chemicals Uncertain Acceptable

3. Salinity and sodicity Acceptable Acceptable

4. Nutrients: nitrogen, phosphorous and organic carbon Acceptable Acceptable

5. Organic chemicals Uncertain Acceptable

6. Turbidity and particulates Uncertain Acceptable

7. Radionuclides Acceptable Acceptable

8. Pressure, flow rates, volumes and groundwater levels Acceptable

9. Contaminant migration in fractured rock and karstic aquifers Acceptable

10. Aquifer dissolution and stability of well and aquitard Acceptable

11. Aquifer and groundwater-dependent ecosystems Acceptable

12. Energy and greenhouse gas considerations Acceptable

In Table 7 an orange result indicates that the risk is considered acceptable but the uncertainty of the assessment is high. No evaluation of the effects of the aeration / mixing tank on the residual hazards has been undertaken as yet. Each of the hazards and


associated maximal and residual risk assessments are discussed in detail in the following sections.


7. DISCUSSION

This discussion focuses on those residual risks assessed in Section 6 as part of the Stage 3 risk assessment (Figure 1) which were determined to pose an unacceptable risk or potentially unacceptable risk.

7.1. Pathogen risks

Pathogen risks were assessed to be acceptable (< 1 × 10-6 DALYs) for all index pathogens. The assessment of the risks involved the QMRA simulations as described in Appendix 5. The QMRA model included UV-disinfection and chlorination post-recovery treatments which have yet to be installed and as such the results of the QMRA will have to be revised when the system is operating and recovery of water is on a continuous basis.

While the risks were found to be acceptable it should be noted that the QMRA simulations are only models. Thus the input probability distribution functions and output human health risks should not be seen as final fixed representations of water quality but rather best approximations which need ongoing revision and which will always have a level of associated uncertainty and variability.

These residual risk estimates will change if there are changes in either source water quality, residence time in the aquifer or pathogen inactivation rates. Results of faecal sterol analysis indicate that at the time of sampling there were no human faecal inputs into the stormwater, consistent with analyses for human pathogens. The assumed pathogen numbers in stormwater used in the QMRA were derived from stormwater guidelines. Accordingly the QMRA results should be viewed as residual risk estimates not as absolute guides to water management to be used in isolation but rather as information to be interpreted in light of other information such as the system operation and water quality monitoring data.

With the current study several assumptions were used in the calculation of the QMRA (e.g. those in Appendix 5). These variables as well as assumed invariants (e.g. the exposure frequency and volumes) all determine how well the QMRA models represent reality. Future work outlined in Section 9 can address these limitations and give confidence of an improved estimate of the residual risk.

While recognising these limitations the strengths and potential of QMRA simulations undertaken here are also clear. For all its limitations QMRA still appears to provide the most credible quantitative synthesis of currently available data and knowledge on risks. Easily conceived endpoint risk measurements (DALYs) which address the primary concern of minimising risks to human health provide clear targets for management actions. This contrasts with older risk assessments for example, coliform-based targets, which did not have as clear a quantitative relationship to risk levels. QMRA provides a way that the water quality monitoring program can directly be used to improve future quantitative microbial risk assessments.

7.2. Inorganic chemical risks

The residual risk assessment indicates that carbonate mineral dissolution and redox processes are expected to be the major influences on the recovered water quality. While dissolution of carbonate minerals increases the concentration of dissolved calcium, magnesium and bicarbonate it does not lead to water quality risks. Furthermore the extent of dissolution is not expected to inhibit the lifetime of the injection wells (Section 6.2).

Redox processes can lead to water quality improvements through removal of nutrients and organic chemicals, but can degrade water quality through increases in iron and arsenic concentrations.


The residual risk from iron was deemed to be acceptable for the ASTR scheme when the aeration tank was included in the treatment train. However, this will require validation as the groundwater quality to date indicates iron concentrations may remain above the 0.3 mg/L aesthetic water quality guideline value.

However the subsurface storage and transfer aspect of the ASTR scheme is not advanced enough to fully evaluate the residual risks from inorganic chemical hazards; in particular the risk due to arsenic mobilisation from the aquifer can not be assessed. The evaluation of hydrogeochemical processes was largely based on operation of the ASTR site in the flushing mode, with injection occurring via the central recovery wells. Injection through the IW wells commenced in September 2008 and as a result there is little data available to assess the subsurface processes and their impact on the quality of recovered water. Future work outlined in Section 9 will help to define the residual risk or if post-recovery treatment options need to be considered to lower the residual risk to an acceptable level.

7.3. Organic chemical risks

The residual risks from organic chemicals were currently assessed to be acceptable; however, there is some uncertainty in this assessment resulting from the sporadic nature of the detections and the multitude of potential chemicals which can be present in urban stormwater. However dispersive mixing within the aquifer will eliminate peak concentrations and unless there are chronic persistent sources the risks will be acceptable. Further verification monitoring is required to confirm this.

Suggested organic chemicals to be monitored are outlined in Appendix 4 based on detections over the previous four years. This coupled with the proposed comprehensive catchment wide organic chemical hazard analysis proposed as part of the future work including the deployment in the groundwater observation wells of passive samplers similar to those described by Page et al. (2008) and batch studies with most frequently detected highest risk chemicals simazine, atrazine and diuron will further reduce uncertainly in the assessment of chemical risks.

7.4. Turbidity / particulate risks

The evaluation of turbidity was largely based on operation of the ASTR site in the flushing mode, with injection occurring via the central recovery wells. Injection through the IW wells commenced in September 2008 and extraction from RW wells commenced in February 2009 as a result there is little data available to assess the production of turbidity and impact on the quality of recovered water. The levels of turbidity in the IW wells during the second year of flushing and the initial water recovered (March 2009) were below the drinking water aesthetic guideline for turbidity. However, the residual risk for turbidity can not be fully defined without additional evaluation of the capacity of the aquifer as a treatment step for turbidity and particulates.

Treatment of turbidity can be achieved in a number of ways, for example by storing the recovered water in holding tanks to allow the particulates to settle out, or by coagulation followed by filtration through granular media. The effect of aeration / mixing tanks on the turbidity of recovered water is yet to be assessed and may represent and additional preventative measure if this is needed.


8. REVISED WATER QUALITY SAMPLING FOR CONTINUOUS IMPROVEMENTS OF THE RISK ASSESSMENT AND MANAGEMENT OF ASTR

Water quality sampling should be continued to be performed within the four broad objectives as described by the Draft MAR Guidelines (EPHC–NHMRC–NRMMC 2008a), these include:

1. Baseline monitoring. This includes the gathering of further information that will underpin and update this risk assessment.

2. Validation monitoring. This includes obtaining further evidence that the elements of the risk management plan will achieve the specified performance requirements, and includes scientific investigations to improve process understandings and knowledge gaps.

3. Operational monitoring. This includes investigations on critical control points (CCPs), and quality control points (QCPs) and supporting programs to assess whether a preventive measure is operating within specified design specifications and is under control.

4. Verification monitoring. This includes the application of procedures, tests and other evaluations, in addition to those used in operational monitoring, to determine compliance with the risk management plan.

Baseline monitoring has been largely completed prior to this report, whereas validation, operational and verification monitoring still need to be performed in the future sequel activities to the ASTR project (Section 9). To date validation monitoring (Page et al. 2008) has focussed on the stormwater harvesting system; future monitoring will focus more on the assessment of the catchment and associated preventative measures including the risks from pathogens (section 6.1) and organic chemicals (section 6.5) the groundwater component, specifically the residual risks from inorganic chemicals (section 6.2) and turbidity (section 6.6). For these four water quality sampling program objectives, specific recommendations with respect to the residual risks that have been identified as being unacceptable are made in the following sections. A list of the analytes to be included in the revised water quality monitoring program are given in Appendix 4.

8.1. Baseline monitoring

The baseline water quality monitoring requirements can be addressed by collection of grab samples of the native groundwater and untreated stormwater using the modified list of analytes presented in Appendix 4. Baseline monitoring will focus on assessment of the native groundwater and untreated stormwater quality for revision of the residual risk assessment.

The focus of the analytes has been changed to reflect the updated knowledge of the residual risks inherent in the system. There are also several recommended changes which include:

• discontinuing faecal sterol sampling as there was no evidence of human derived faecal pollution in the stormwater;

• a complete revision of the organic chemical / pesticide suite in light of the detections of organic chemicals by passive samplers (see Appendix 4 for the modified list). The list of monitored organic chemicals has been reduced to focus only on those chemicals which have been detected by conventional grab sampling.


8.2. Validation monitoring

Validation monitoring is used to determine whether the ASTR project meets health and environmental targets for drinking water supplies. Research and investigative studies and monitoring are included within the validation monitoring program and include strategic programs designed to increase understanding of the system, to identify and characterise potential hazards, and to fill knowledge gaps. Recommended validation monitoring includes:

• Investigation of the subsurface system, especially with regard to the extent of mixing with ambient groundwater and residence times in subsurface storage via sampling of piezometers.

• Measurement of organic chemical decay rates by batch studies using aquifer sediment material.

• Measurement of organic chemicals in piezometers and recovered water using passive samplers.

• Monitoring of iron, arsenic and redox state in wells and piezometers to allow calibration of a geochemical model to predict operational characteristics to avoid onset of metal mobilization

• Continued source water monitoring to understand the temporal and spatial variability of water quality parameters to assess if the poor rainfall and low flows experienced in 2006-2008 has resulted in atypical source water quality for the system.

• A hazard analysis of the urban catchment, understanding what preventative measures could be used to manage an urban catchment.

• Future recovery of the ASTR water to mains may require additional treatment such as UV or chlorination disinfection. Treatment requirements need to be determined based on the recovered water quality as well as any potential effects that may arise from blending with mains water.

• Assessment of blended water quality and effect on distribution infrastructure.

One of the objectives of validation monitoring is to prove that the system delivers the expected water quality. Therefore, operational monitoring, discussed below, is generally performed at the same time as validation monitoring especially when considering appropriate critical limits.

8.3. Operational monitoring

Operational monitoring is the routine monitoring of control parameters and at critical control points identified in the ASTR project, to confirm that the system is being appropriately managed. It provides advance warning that systems may be deviating to a point where control will be lost. Future operational monitoring should assess and confirm the performance of preventive measures, key elements include:

• addition of conductivity measurements for each of the Parafield ASR wells if they continue to supply water to the ASTR system and meters to record such supplies. This will help improve the water and chloride balance for future assessment of system treatment performance and residence time in the cleansing reedbed when switching between stormwater and ASR groundwater inflows.

• identification and revision of the parameters and criteria at CCPs used to measure operational effectiveness and, where necessary, trigger corrective actions. Specifically a calibration review of CCPs and associated equipment should be included. This includes conductivity and turbidity probes and future CCPs that will be utilised in the catchment or subsurface to manage water quality.


• ongoing review and interpretation of results to confirm operational performance. Current CCPs are never breached and so tighter constraints to water quality could be considered to reduce the overall risk. This includes determining response times and suitable actions documented in a plan if the control limits are exceeded.

• correlation of CCPs to other hazards to determine the utility of CCPs to be surrogate measures for other hazards, e.g. pathogens, organic chemicals.

• regular inspection of the ASTR facilities and maintenance of plant and equipment, including site inspections and intake structures of the water quality stations. Development of a regular inspection schedule that is auditable.

Each of these operational monitoring requirements will form the basis of the risk management plan outlined in Appendix 8.

8.4. Verification monitoring

The purpose of verification monitoring is to confirm compliance with the risk management plan. Verification of water quality assesses the overall performance of the ASTR system, the ultimate quality of water being supplied or discharged.

Verification monitoring requirements should be developed in conjunction with human health and environmental risk regulators as part of the ASTR risk management plan (Appendix 8). In terms of water quality monitoring, this will be performed at the recovery wells on the extracted water to confirm that it meets the Australian Drinking Water Guidelines (using the revised monitoring suite in Appendix 4 as a basis) and that the system is operating to produce recovered water intended for but prior to distribution.


9. CONCLUSIONS AND RECOMMENDATIONS

Figure 8 illustrates the progress in the implementation of the ASTR risk management plan following the initial work by Swierc et al. (2005), later developed by Page et al. (2008) and finally in this current report aligned with the 12 elements described in the Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (NRMMC–EPHC–AHMC 2006); 2A Augmentation of Drinking Water Supplies (EPHC–NHMRC–NRMMC 2008b) and draft 2C Managed Aquifer Recharge (EPHC–NHMRC–NRMMC 2008a) in this report.

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Commitment to responsible use and

management of recycled water quality

Assessment of the MAR system

Preventive measures for recycled water

management

Operational procedures and process

control

Verification of water quality and

environmental performance

Management of incidents and

emergencies

Operator, contractor and end user

awareness and training

Community involvement and

awareness

Validation, research and development

Documentation and reporting

Evaluation and audit

Review and continuous improvement

HA

CC

P E

lem

en

t

Percentage complete

Swierc et al. (2005)

Page et al. (2008)

This report

Figure 8 Progress of the ASTR plan against the 12 elements of the Australian Guidelines for Water Recycling

Figure 8 illustrates the progression of the ASTR project against each of the 12 elements. Most progress was made in the assessment of the ASTR system (element 2), but additional work is required in establishing and documenting the operation of the system and providing timely responses that are auditable.

The next refinement of this risk assessment should be extended to include a risk management plan. A gap analysis of the requirements to form a risk management plan is given in Appendix 8. All of these elements would need to be completed prior to recovery of stormwater to the mains supply. It is recommended that project partners undertake the actions identified as necessary to address the gaps in the risk management plan.


REFERENCES

AGT (2007). Final draft Parafield ASTR wells completion report and aquifer test results. AGT Report no 2077/22, Australian Groundwater Technologies PTY LTD, Wayville, South Australia.

ANZECC–ARMCANZ (Australian and New Zealand Environmental and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand) (2000). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. National Water Quality Management Strategy Paper no 4. ANZECC–ARMCANZ, Canberra.

APHA–AWWA–WEF (American Public Health Association, American Water Works Association and Water Environment Federation) (2005). Standard methods for the examination of water and wastewater, 21st Ed, American Public Health Association, Washington, D.C.

Dillon, P. and Toze, S. (2005). Water quality improvements during aquifer storage and recovery. Volume 1: Water quality improvements processes. American Water Works Association Research Foundation (AwwaRF) report number 91056F, Denver, USA.

Dillon, P., Page, D., Pavelic, P., Toze, S., Vanderzalm, J., Barry, K., Levett, K., Regel, R., Rinck-Pfeiffer, S., Pitman, C., Purdie, M., Marles, C., Power, N. and Wintgens, T. (2008). City of Salisbury’s progress towards being its own drinking water catchment. Proceedings of the IWA conference Singapore Water Week June 2008.

Dillon, P., Kumar, A., Kookana, R., Leijs, R., Reed, D., Ingerson, G. and Shareef, A. (2009). Managed Aquifer Recharge - Risks to Groundwater Dependent Ecosystems. CSIRO Water for a Healthy Country Flagship Report to Land and Water Australia, December 2008.

EPHC–NHMRC–NRMMC (2008a). Australian Guidelines for Water Recycling: Managing Health and Environmental Risks. Phase 2C: Managed Aquifer Recharge, Environment Protection and Heritage Council, National Health and Medical Research Council, and Natural Resource Management Ministerial Council, draft released for pubic consultation May 2008, www.ephc.gov.au/taxonomy/term/39

EPHC–NHMRC–NRMMC (2008b). Australian Guidelines for Water Recycling: Managing Health and Environmental Risks. Phase 2A: Augmentation of Drinking Water Supplies, (Environment Protection and Heritage Council, Natural Resource Management Ministerial Council and National Health and Medical Research Council, www.ephc.gov.au/taxonomy/term/39

EPHC–NHMRC–NRMMC (2008c). Australian Guidelines for Water Recycling: Managing Health and Environmental Risks. Phase 2B: Stormwater, Environment Protection and Heritage Council, Natural Resource Management Ministerial Council and National Health and Medical Research Council, draft released for public consultation May 2008, www.ephc.gov.au/taxonomy/term/39

Gerges, N. Z. (2005). Greenfield Railway Station ASTR Project Briefing on Aquifer Tests. NZG Groundwater Consultant, Hallet Cove, SA.

Kenway, S.J., Priestley, A., Cook, S., Seo, S., Inman, M., Gregory, A. and Hall, M. (2008). Energy use in the provision and consumption of urban water in Australia and New Zealand. CSIRO: Water for a Healthy Country National Research Flagship.

Kremer, S. Pavelic, P., Dillon, P and Barry, K. (2008). Flow and Solute Transport Observations and Modelling from the First Phase of Flushing Operations at the Salisbury ASTR Site. CSIRO: Water for a Healthy Country National Research Flagship.

Leeming, R., Ball, A., Ashbolt, N. and Nichols, P. (1996). Using faecal sterols from humans and animals to distinguish faecal pollution in receiving waters, Water Research, 30, 12, 2893-2900.

Marks, R., Chapman, F., Lane, S. and Purdie, M. (2005). Parafield urban stormwater harvesting facility, Australian Water Association Journal Water, 32, pp. 42-45.


NHMRC–NRMMC (National Health and Medical Research Council and Natural Resource Management Ministerial Council) (2004). Australian Drinking Water Guidelines, NHMRC and NRMMC, Canberra. http://www.nhmrc.gov.au/publications/_files/adwg_11_06.pdf

Nichols, P. D., Leeming, R., Rayner, M. S., and Latham, V. (1996). Use of capillary gas chromatography for measuring faecal sterol derived sterols: application to stormwater, the sea surface microlayer, beach greases, regional studies and distinguishing algal blooms and human and non-human sources of sewage pollution. Journal of Chromatography, 733A, 469–509.

NRMMC–EPHC–AHMC (Natural Resource Management Ministerial Council, Environment Protection and Heritage Council, and Australian Health Ministers’ Conference) (2006). Australian Guidelines for Water Recycling: Managing Health and Environmental Risks: Phase 1. National Water Quality Management Strategy. NRMMC–EPHC–AHMC, Canberra, Australia.

Pavelic, P., Dillon, P. and Robinson, N. (2004). Groundwater Modelling to Assist Well-Field Design and Operation for the ASTR Trial at Salisbury, South Australia. CSIRO Land and Water Technical Report No. 27/04.

Page, D., Wakelin, S., van Leeuwen, J. and Dillon, P. (2006). Review of biofiltration processes relevant to water reclamation via aquifers. CSIRO, Adelaide.

Page, D., Barry, K., Pavelic, P., Dillon, P. and Chassagne, A. (2008). Preliminary quantitative risk assessment for the Salisbury stormwater ASTR project. CSIRO: Water for a Healthy Country National Research Flagship.

Page, D., Dillon, P. and Bartkow, M. (in preparation) Quantification of herbicide removals in a full scale constructed wetland using composite water quality monitoring and passive samplers.

Parkhurst, D. L. and Appelo, C. A. J. (1999). User’s guide to PHREEQC (version 2) – a computer program for speciation, batch-reaction, one-dimensional transport and inverse geochemical calculations. Water-resource Investigations Report 99-4259. U. S. Geological Survey, Denver, Colorado.

PMSEIC (2007) Water for our cities: building resilience in a climate of uncertainty, Prime Ministers Science Engineering and Innovation council, www.dest.gov.au/sectors/science_innovation/publications_resources/profiles/water_for_our_cities.htm

SA Water Corporation (2007). SA Water Annual Report 2006-07. SA Water Corporation.

Stuyfzand P. J. (1998). Quality changes upon injection into anoxic aquifer in the Netherlands: evaluation of 11 experiments. In (J. H. Peters ed.) Third International Symposium on Artificial Recharge TISAR98, Amsterdam, Netherlands, 21-25 September 1998. A. A Balkema, Amsterdam, pp 283-291.

Swierc, J., Page, D.W., van Leeuwen, J.A., and Dillon, P. (2005). Preliminary Hazard Analysis and Critical Control Point (HACCP) – Salisbury stormwater to drinking water aquifer storage transfer and recovery (ASTR) project, CSIRO Land and Water Technical Report No. 20/05.

Tomlinson, M. and Boulton, A. (2008). Subsurface groundwater dependent ecosystems: a review of their biodiversity, ecological processes and ecosystem services. Waterlines Occasional Paper No 8. National Water Commission, Canberra.

Toze, S. and Hanna, J. (2002). The survival of enteric microbial pathogens in a reclaimed water ASR project. In (P. J. Dillon ed.) Management of Aquifer Recharge for Sustainability Proceedings of ISAR-4, Adelaide, South Australia, 22-26 September, 2002. A. A. Balkema, Netherlands, pp 139-142.

Toze, S., Sidhu, J., Shackleton, M., Hodgers, L., and Gama, S. (2008). Decay of Microbial Pathogens in a Constructed Reedbed Receiving Storm Water for Pre-Treatment Prior to


Aquifer Storage, Transfer and Recovery. CSIRO: Water for a Healthy Country National Research Flagship.

Toze, S., Sidhu, J., Shackleton, M., and Hodgers, L. (2009). Decay of Enteric Pathogens in Urban Stormwater Recharged to an Aquifer using Aquifer Storage, Transfer and Recovery. CSIRO: Water for a Healthy Country National Research Flagship.

Vanderzalm, J. L., Dillon, P. J. and Le Gal La Salle, C. (2007). Arsenic mobility under variable redox conditions induced during ASR. In (P. Fox ed.) Management of Aquifer Recharge for Sustainability Proceedings of ISMAR6, Phoenix, 28 October-2 November, 2007. Acacia Publishing Inc., Arizona pp 209-219. Vanderzalm, J.L., Le Gal La Salle, C. and Dillon, P. J. (2006). Fate of organic matter during aquifer storage and recovery (ASR) of reclaimed water in a carbonate aquifer. Applied Geochemistry 21: 1204-1215.


water ASTR project

Page 44

AP

PE

ND

IX 1

RE

ED

BE

D W

AT

ER

QU

AL

ITY

DA

TA

SU

MM

AR

Y 2

00

6-2

00

8

Tab

le A

1-1

AS

TR

re

ed

be

d in

let

(WE

1)

wate

r q

ua

lity

data

su

mm

ary

200

6-2

00

8

2006

2007

2008

D

WG

M

ean

<

gu

ideli

ne

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Fie

ld r

ead

ing

s

EC (µS/cm)

- �

1

149

5

144

217

209

188

35.9

Temperature (°C

) -

�

1

9.0

5

10.3

12.9

10.8

11.1

1.0

pH (pH units)

6.5-8.5

�

1

6.6

5

6.5

7.7

7.4

7.2

0.5

DO (mg/L)

85%

�

1

9.3

5

5.6

9.8

8.8

8.0

1.8

Eh (mV SHE)

- �

1

454

5

334

397

371

367

23

Ph

ysic

al ch

ara

cte

risti

cs


- �

5

164

223

218

206

24

6

158

314

225

228

51

5

156

220

216

194

33

pH (pH units)

6.5-8.5

�

5

7.1

7.6

7.4

7.3

0.2

6

7.1

7.5

7.4

7.4

0.1

5

7.1

7.3

7.2

7.2

0.1

Suspended Solids

(mg/L)

- �

5

<1

130

4

28

57

6

4

15

6

7

4.1

5

1

24

12

11

9.3

Total Dissolved Solids

(mg/L; by EC)

500

�

5

90

122

120

112

13

6

87

170

120

123

27

5

86

120

120

107

18

Turbidity (NTU)

5

�

5

2.7

97

5.2

23

41

6

6.6

15

9.4

10

3.0

5

12

26

24

20

6.6

True Colour (H

U)

15

�

5

39

83

67

66

18

Majo

r io

ns (

mg

/L)

Alkalinity as CaCO

3

- �

5

50

96

54

63

19

6

41

76

52

53

13

5

43

55

54

50

6

Bicarbonate

- �

5

61

117

66

77

23

6

50

93

63

64

16

5

53

67

66

61

7

Bromide

- �

5

0.06

0.09

0.06

0.06

0.02

5

<0.1

Sulfate

250

�

5

8.7

11.7

11.4

10.9

1.2

6

7.2

13.2

9.8

9.9

1.9

5

8.4

12.9

11.1

10.6

1.8

Chloride

250

�

5

17

28

21

22

5.3

6

17

51

31

32

12

5

17

29

28

24

6.4

Fluoride

1.5

�

5

0.13

0.51

0.15

0.22

0.2

6

0.1

0.15

0.12

0.12

0.02

5

0.12

0.17

0.14

0.14

0.02

Calcium

- �

5

15.0

20.9

17.0

17.4

2.2

6

14.4

25.9

18.6

19.1

4.2

5

14.6

20.5

19.8

18.1

2.8

Magnesium

- �

5

3.2

4.6

4.3

4.02

0.6

6

2.6

5.4

4

4.0

0.9

5

2.4

3.5

3.4

3.1

0.6

Potassium

- �

5

3.6

5.6

4.4

4.4

0.8

6

2.4

3.9

3.5

3.2

0.6

5

2.4

3.5

3.2

3.0

0.4

Sodium

180

�

5

12.5

17.9

17.5

16.1

2.3

6

13.1

25.8

18.2

19.0

4.2

5

11.0

18.7

17.3

15.4

3.6

Mic

rob

iolo

gic

al

Coliform

s (cfu/100 m

L)

-

5

440

2x105

2.3x103

4.1x104

8.8 x104

6

180

6.9x104

4.5x103

1.8x104

2.7x104

E.coli (cfu/100 m

L)

0

�

5

0

260

3

54

115

6

0

570

34

128

220

5

1

140

12

40

58


water ASTR project

Page 45

Tab

le A

1-1

co

nti

nu

ed

. A

ST

R r

eed

bed

in

let

(WE

1)

2006

2007

2008

D

WG

M

ean

<

gu

ideli

ne

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D


L)

0

�

5

0

35

11

15

16

6

0

610

16.5

116

243

5

5

430

47

118

177

Therm

otolerant coliform

s

(cfu/100 m

L)

0

�

5

0

260

5

55

115

6

0

710

45

155

275

5

1

140

12

50

62

Faecal Streptococci

(cfu/100 m

L)

0

�

5

0

35

11

15

16

6

0

610

16.5

116

243

5

5

430

47

118

177

F-specific phage

(MPN/L)^

- �

7

13

>94

7*

1

>94

1*

5

2

13

5*

Somatic phage (MPN/L)^

- �

7

13

>94

7*

1

ND

5

13

>94

5*

Clostridium spores

(cfu/L)^

0

�

1

+ve

1*

5

270

>1000

5*

Campylobacter (cfu/L)^

0

�

1

+ve

1*

5

ND

Cryptosporidium

(oocysts/L)^

0

�

1

ND

5

ND

Enteric virus (PDU/L)^

0

�

5

ND

Nu

trie

nts

(m

g/L

)

Nitrate + Nitrite as N

11.3

�

5

<0.005

0.021

0.011

0.0117

0.01

6

0.025

0.166

0.081

0.093

0.06

5

<0.005

0.104

0.087

0.071

0.040

Ammonia as N

0.5

�

5

0.006

0.444

0.155

0.171

0.174

6

<0.005

0.137

0.107

0.088

0.051

5

<0.005

0.108

0.067

0.064

0.041

Total Kjeldahl Nitrogen

- �

5

0.45

2.1

0.65

0.87

0.67

6

0.33

0.81

0.58

0.57

0.19

5

0.43

0.91

0.48

0.60

0.21

Total Nitrogen

- �

5

0.46

2.08

0.66

0.886

0.68

6

0.49

0.84

0.66

0.67

0.15

5

0.52

0.92

0.58

0.67

0.17

Filterable Reactive

Phosphorus

- �

5

0.010

0.041

0.020

0.024

0.013

6

0.023

0.030

0.027

0.027

0.003

5

0.010

0.019

0.013

0.014

0.004

Total Phosphorus

- �

5

0.038

0.320

0.070

0.112

0.12

6

0.059

0.093

0.070

0.073

0.014

5

0.052

0.102

0.069

0.076

0.020

Dissolved O

rganic

Carbon

- �

5

5.4

9.1

8.6

8.1

1.5

6

3.9

9.6

8.7

7.4

2.7

5

4.3

6.4

5.1

5.2

0.94


- �

5

6.0

21

9.7

11.2

5.7

6

4.4

10

9.5

8.0

2.7

5

5.1

7.9

5.8

6.3

1.3

UV

254 (cm

-1)

- �

5

0.245

0.386

0.336

0.327

0.051

5

0.169

0.332

0.321

0.263

0.085

5

0.134

0.207

0.161

0.161

0.030

Meta

ls a

nd

meta

llo

ids (

mg

/L)

Aluminium (t)

0.2

�

5

0.143

0.560

0.197

0.313

0.200

6

0.085

0.320

0.164

0.185

0.099

5

0.060

0.866

0.644

0.499

0.36

Arsenic (t)

0.007

�

5

<0.001

0.005

<0.001

<0.001

0.002

5

<0.001

0.001

5

<0.001

0.001

0.0005

0.0007

0.0003

Arsenic (s)

- �

5

<0.001

0.004

<0.001

0.001

0.002

5

<0.001

0.001

0.001

0.001

0.000

3

<0.001

0.001

0.001

0.001

0.0000

Barium (t)

0.7

�

5

0.015

0.024

0.019

0.019

0.004

5

0.018

0.024

0.020

0.020

0.002

Boron (s)

4

�

4

0.046

0.064

0.052

0.054

0.008

5

<0.040

Cadmium (t)

0.002

�

5

<0.0005

0.0006

<0.0005

<0.0005

<0.0005

6

<0.0005

5

<0.0005

Chromium (t)

0.05

�

5

<0.003

0.004

<0.003

<0.003

<0.003

6

<0.003

0.006

<0.003

<0.003

<0.003

5

<0.003

0.003

0.002

0.002

0.001


water ASTR project

Page 46

Tab

le A

1-1

co

nti

nu

ed

. A

ST

R r

eed

bed

in

let

(WE

1)

2006

2007

2008

D

WG

M

ean

<

gu

ideli

ne

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Copper (t)

1

�

6

0.003

0.006

0.004

0.004

0.001

5

0.003

0.005

0.004

0.004

0.001

Iron (t)

0.3

�

5

0.464

0.623

0.543

0.546

0.062

6

0.289

0.402

0.369

0.359

0.045

5

0.190

0.760

0.554

0.527

0.229

Iron (s)

- �

5

0.087

0.362

0.251

0.254

0.116

5

0.045

0.268

0.164

0.163

0.089

5

0.068

0.699

0.106

0.249

0.264

Lead (t)

0.01

�

5

0.0005

0.0044

0.0019

0.0022

0.0015

6

0.0009

0.0022

0.0017

0.0016

0.0005

5

0.0010

0.0044

0.0032

0.0030

0.0014

Lead (s)

- �

5

<0.0005

0.0007

0.00025

0.00034

0.00

4

0.0010

0.0051

0.0014

0.0022

0.0020

Lithium (t)

- �

6

0.001

0.004

0.002

0.002

0.001

5

0.002

0.003

0.002

0.002

0.000

Manganese (t)

0.1

�

5

0.021

0.050

0.035

0.035

0.010

6

0.013

0.027

0.024

0.023

0.005

5

0.012

0.023

0.016

0.017

0.004

Manganese (s)

- �

5

0.007

0.042

0.012

0.020

0.016

5

0.007

0.021

0.012

0.014

0.005

Mercury (t)

0.001

�

6

<0.0003

5

<0.0003

Molybdenum (t)

0.05

�

6

<0.0005

0.0013

<0.0005

0.0009

0.0004

5

0.0005

0.0053

0.0028

0.0030

0.0020

Nickel (t)

0.02

�

5

0.0007

0.0013

0.0009

0.0010

0.0003

6

0.0007

0.0019

0.0009

0.0012

0.0005

5

<0.0005

0.0009

0.0005

0.0005

0.0003

Vanadium (t)

- �

6

<0.003

0.004

<0.003

<0.003

<0.003

5

<0.003

0.003

0.002

0.002

0.001

Zinc (t)

3

�

5

0.018

0.101

0.041

0.053

0.031

6

0.025

0.059

0.032

0.037

0.014

5

0.042

0.079

0.066

0.060

0.016

Ste

rols

(n

g/L

)

24-ethylcholestanol

�

2

50

90

70

70

28

5

143

326

184

208

76

24-ethylcholesterol

�

2

736

976

856

856

170

5

1720

9920

2600

4978

3779

24-ethylcoprostanol

�

2

<40

<67

5

<50

90

44

48

25

24-ethylepicoprostanol

�

2

<40

<67

5

<50

<80

Cholestanol

�

2

51

80

66

66

21

5

85

450

189

229

145

Cholesterol

7000

�

2

665

1210

938

938

385

5

1170

6590

1750

2958

2285

Coprostanol

700

�

2

<40

<67

5

<50

140

44

59

46

Epicholestanol

�

2

<40

<67

3

<50

82

44

50

29

Epicoprostanol

�

2

<40

<67

5

<50

<80

Tri

halo

meth

an

es f

orm

ati

on

po

ten

tial (F

P)

(µg

/L)

Bromoform

FP

100

�

1

<1

5

<1

Chloroform

FP

200

�

1

129

5

118

196

154

161

34

Dibromochloroform

FP

- �

1

4

5

<1

2

1

1

1

Dichlorobromoform

FP

- �

1

33

5

18

30

22

23

5

Total Trihalomethanes FP

250

�

1

166

5

136

226

181

185

38


water ASTR project

Page 47

Tab

le A

1-1

co

nti

nu

ed

. A

ST

R r

eed

bed

in

let

(WE

1)

2006

2007

2008

D

WG

M

ean

<

gu

ideli

ne

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Halo

aceti

c a

cid

fo

rmati

on

po

ten

tial

(FP

) (µ

g/L

)

Bromoacetic Acid FP

0.35

�

1

1

Bromochloroacetic Acid

FP

- �

1

11

Bromodichloroacetic Acid

FP

- �

1

34

Chloroacetic Acid FP

- �

1

<5

Dibromoacetic Acid FP

- �

1

2

Dichloroacetic Acid FP

100

�

1

75

Trichloroacetic Acid FP

100

�

1

100

Org

an

ic c

hem

icals

(µ

g/L

un

less o

therw

ise s

pecif

ied

)

Caffeine

0.35

�

4

0.23

0.31

0.30

0.28

0.04

DEET

2500

�

4

0.05

0.08

0.06

0.06

0.01

Desisopropyl Atrazine

- �

4

<0.01

0.01

0.01

0.01

0.003

Dicamba

100

�

4

<0.01

0.08

0.04

0.04

0.04

Diuron

30

�

4

0.09

0.18

0.17

0.15

0.04

MCPA

35^

�

4

0.18

0.42

0.40

0.35

0.11

Mecoprop

350

�

4

0.01

0.03

0.02

0.02

0.01

Metolachlor

300

�

4

<0.01

0.01

<0.01

0.006

Nitroso-piperidine (ng/L) -

�

4

<10

54

36

33

22

Paracetamol

175

�

4

0.05

0.08

0.07

0.07

0.02

Sim

azine

5

�

4

0.04

0.66

0.63

0.49

0.30

Triclopyr

10

�

4

0.03

0.04

0.03

0.03

0.01

Sim

azine#

5

�

6

<0.1

0.8

0.05

0.24

0.32

5

<0.1

0.86

0.05

0.33

0.39

Detergent as M

BAS (mg/L) -

�

6

<50

120

95.0

76.7

41.2

5

70

110

90.0

88.0

14.8

Dichloromethane

4

�

6

<1

1.4

<1

<1

0.37

5

<1

Bis(2-ethylhexyl)phthalate

- �

6

<20

5

<20

33

<20

<20

<20

DWG = drinking water guidelin

e, taken from Australia

n D

rinking W

ater Guidelin

es, or 2A: Augmentation of Drinking W

ater Supplies guidelin

es; (t) = total; (d) = dissolved; ND = N

ot

detected; * = number of detects; ^ = summary statistics not possible due to the use of MPN (most probable number) technique, analysis at CSIRO; #

= analysis from different

laboratory, using higher detection lim

it


water ASTR project

Page 48

Tab

le A

1-2

AS

TR

re

ed

be

d o

utl

et

(WE

2)

wate

r q

uali

ty d

ata

su

mm

ary

20

06-2

00

8

D

WG

M

ean

<

gu

idelin

e

2006

2007

2008

n

M

in

Max

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Fie

ld r

ead

ing

s

EC (µS/cm)

- �

2

286

307

297

297

2

163

214

188

188

6

154

372

212

223

77

Temperature (°C

) -

�

2

15.6

19.7

17.7

17.7

2

6.9

8.0

7.5

7.5

6

8.2

21.2

10.9

12.1

4.7

pH (pH units)

6.5-8.5

�

2

6.8

6.8

6.8

6.8

2

6.7

7.9

7.3

7.3

6

6.6

8.1

7.0

7.1

0.6

DO (mg/L)

85%

�

2

3.1

3.6

3.4

3.4

2

4.8

7.2

6.0

6.0

6

2.9

7.6

4.8

5.1

1.9

Eh (mV SHE)

- �

2

306

361

334

334

2

338

380

359

359

6

315

402

376

369

31

Ph

ysic

al

ch

ara

cte

risti

cs


- �

19

179

361

265

262

64

9

167

251

217

214

27

6

161

345

211

222

65

pH (pH units)

6.5-8.5

�

19

6.9

7.7

7.2

7.3

0.2

9

6.8

7.5

6.9

7.0

0.2

6

6.6

6.9

6.8

6.7

0.1

Suspended Solids

(mg/L)

- �

15

<1

6

2.8

2.7

1.3

9

<1

14

4

5.8

4.5

5

2

8

4

4.8

2.3

Total Dissolved

Solids (mg/L; by EC)

500

�

19

98

200

150

144

36

9

92

140

120

118

16

6

88

190

115

121

36

Turbidity (NTU)

5

�

19

1.3

6.2

3

3.4

1.5

9

1.4

13

2.4

4.3

3.8

6

2

10

5.2

5.4

3.0

True Colour (H

U)

15

�

19

12

86

53

47

26

Majo

r io

ns (

mg

/L)

Alkalinity as CaCO

3

- �

19

25

118

57

76

31

9

43

64

57

54

7.2

6

44

109

53

68

29

Bicarbonate

- �

19

30

144

70

93

38

9

53

78

69

66

8.7

6

54

132

65

83

35

Bromide

- �

19

0.04

0.14

0.05

0.07

0.03

5

<0.1

Sulfate

250

�

16

7.8

20.4

10.2

11.0

3.0

9

7.8

10.8

8.4

8.8

1.1

6

9

15.3

10.2

11.1

2.44

Chloride

250

�

19

12

46

26

26

9.0

9

18

38

29

29

5.6

6

17

41

28

27

8.2

Cyanide

0.08

�

1

<0.05

Fluoride

1.5

�

19

0.13

0.29

0.16

0.19

0.06

9

0.1

0.14

0.12

0.12

0.01

6

0.12

0.22

0.15

0.15

0.04

Calcium

- �

19

15.2

36.1

18.6

24.2

8.7

9

14.7

23.6

17.3

18.6

2.9

6

15.1

32.9

18.9

20.5

6.4

Magnesium

- �

19

3.2

10.6

5

5.6

2.1

9

2.9

4.5

3.8

3.9

0.51

6

2.6

6.7

3.3

3.7

1.5

Potassium

- �

19

2.4

7.8

4.1

4.4

1.5

9

2.5

4

2.8

3.0

0.48

6

2.6

3.5

3.2

3.2

0.3

Sodium

180

�

19

12.2

27.9

18.7

18.5

4.5

9

13.9

22

18.1

17.9

2.7

6

12.8

29.5

17.6

18.3

5.9

Mic

rob

iolo

gic

al

(mg

/L)

Coliform

s (cfu/100 m

L)

- �

19

690

1.6x104

2.6x103

3.9x103

4.1x103

9

440

4.8x103

2.3x103

2.3x103

1.5x103

1

3.4x104

E.coli (cfu/100 m

L)

0

�

19

3

140

17

36

39

9

2

77

13

23

24

5

4

220

17

52

94


L)

0

�

19

1

96

11

20

25

9

3

82

13

23

27

6

13

110

29

40

36


water ASTR project

Page 49

Tab

le A

1-2

co

nti

nu

ed

. A

ST

R r

eed

bed

ou

tle

t (W

E2)

D

WG

M

ean

<

gu

idelin

e

2006

2007

2008

n

M

in

Max

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Therm

otolerant

coliform

s (cfu/100 m

L)

0

�

19

4

140

17

37

39

9

2

77

13

24

24

6

4

220

17

49

84

Faecal Streptococci

(cfu/100 m

L)

0

�

19

1

96

11

20

25

9

3

82

13

23

27

6

13

110

29

40

36

F-specific phage

(MPN/L)^

- �

5

2

13

5*

Somatic phage

(MPN/L)^

- �

7

ND

>94

7*

1

ND

5

2

>94

5*

Clostridium spores

(cfu/L)^

0

�

7

ND

>94

7*

1

ND

5

ND

>1000

4*

Campylobacter (cfu/L)^

0

�

1

78

1*

5

ND

Cryptosporidium

(oocysts/L)^

0

�

1

ND

5

ND

Enteric virus (PDU/L)^

0

�

5

ND

Nu

trie

nts

(m

g/L

)


11.3

�

19

<0.005

0.151

0.003

0.011

0.034

9

<0.005

0.022

0.003

0.007

0.008

6

<0.005

0.009

0.003

0.004

0.003

Ammonia as N

0.5

�

19

<0.005

0.195

0.014

0.029

0.05

9

<0.005

0.113

0.016

0.026

0.04

6

<0.005

0.008

0.004

0.004

0.002

Total Kjeldahl Nitrogen

- �

19

0.26

0.74

0.45

0.45

0.15

9

0.2

0.56

0.34

0.35

0.12

6

0.28

0.86

0.28

0.38

0.24

Total Nitrogen

- �

19

0.26

0.81

0.46

0.46

0.17

9

0.22

0.56

0.34

0.35

0.11

6

0.28

0.86

0.29

0.38

0.23

Filterable Reactive

Phosphorus

- �

19

<0.005

0.040

0.017

0.017

0.013

9

0.007

0.027

0.011

0.012

0.006

6

<0.005

0.006

0.006

0.005

0.002

Total Phosphorus

- �

19

0.021

0.095

0.058

0.055

0.024

9

0.024

0.097

0.041

0.050

0.026

6

0.023

0.042

0.030

0.030

0.007

Biodegradable

Dissolved O

rganic

Carbon

- �

1

1

3

1.8

3.4

1.9

2.4

0.9

Dissolved O

rganic

Carbon

- �

19

3.8

11.7

6.9

6.9

2.5

9

3.4

8.2

5.8

5.7

2.0

6

3.7

4.7

4.1

4.2

0.4


- �

19

4.3

12.8

7.7

7.76

2.64

9

3.9

9.5

7.3

6.63

2.35

6

4.5

5.5

4.75

4.9

0.40

UV

254 (cm

-1)

- �

19

0.148

0.467

0.275

0.289

0.101

8

0.149

0.284

0.211

0.213

0.056

5

0.109

0.154

0.125

0.130

0.017

Meta

ls a

nd

meta

llo

ids (

mg

/L)

Aluminium (t)

0.2

�

19

0.021

0.767

0.062

0.160

0.245

9

0.030

0.410

0.060

0.144

0.140

6

0.062

0.495

0.211

0.238

0.172

Antimony (t)

0.003

�

2

0.0006

0.0131

0.0069

0.0069

0.009

5

<0.0005

0.0014

0.0007

0.0008

0.0004

Arsenic (t)

0.007

�

19

<0.001

0.006

<0.001

0.001

0.002

9

<0.001

0.001

<0.001

<0.001

<0.001

6

0.0005

0.0020

0.0008

0.0009

0.0006

Arsenic (s)

- �

17

<0.001

0.006

<0.001

0.002

0.002

7

<0.001

5

0.001

0.002

0.001

0.001

0.000

Barium (t)

0.7

�

2

0.020

0.024

0.022

0.022

0.003

9

0.012

0.019

0.014

0.015

0.002

6

0.016

0.019

0.018

0.018

0.001

Boron (s)

4

�

2

0.048

0.060

0.054

0.054

0.008

9

<0.02

0.108

0.051

0.05

0.03

6

<0.04

0.054

0.020

0.026

0.014


water ASTR project

Page 50

Tab

le A

1-2

co

nti

nu

ed

. A

ST

R r

eed

bed

ou

tle

t (W

E2)

D

WG

M

ean

<

gu

idelin

e

2006

2007

2008

n

M

in

Max

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Cadmium (t)

0.002

�

19

<0.0005

9

<0.0005

6

<0.0005

Chromium (t)

0.05

�

18

<0.003

0.017

<0.003

0.003

0.004

9

<0.003

0.003

<0.003

<0.003

<0.003

6

<0.003

0.004

0.002

0.002

0.001

Cobalt (t)

- �

1

<0.020

5

<0.0005

0.0005

0.00025

0.0003

0.0001

Cobalt (s)

- �

5

<0.005

Copper (t)

1

�

2

<0.030

<0.030

<0.030

9

<0.001

0.002

0.002

0.002

0.001

6

<0.001

0.003

0.002

0.002

0.001

Iron (t)

0.3

�

19

0.247

1.200

0.610

0.633

0.310

9

0.258

0.743

0.441

0.476

0.165

6

0.203

0.484

0.393

0.366

0.112

Iron (s)

- �

17

0.011

0.534

0.234

0.224

0.174

7

0.029

0.229

0.194

0.159

0.079

6

0.019

0.238

0.080

0.101

0.075

Lead (t)

0.01

�

19

<0.0005

0.0036

0.0005

0.0007

0.0008

9

<0.0005

0.0012

<0.0005

0.0005

<0.0005

6

<0.0005

0.0012

0.0005

0.0006

0.0004

Lead (s)

- �

7

<0.0005

6

<0.0005

Lithium (t)

- �

2

<0.010

9

0.0015

0.0033

0.0020

0.0021

0.0006

6

0.0013

0.0027

0.0020

0.0020

0.0006

Manganese (t)

0.1

�

19

0.003

0.213

0.042

0.056

0.053

9

0.008

0.056

0.038

0.032

0.016

6

0.0131

0.0823

0.0171

0.0281

0.0269

Manganese (s)

- �

15

0.003

0.135

0.012

0.023

0.033

5

0.0082

0.0226

0.0109

0.0143

0.0065

Mercury (t)

0.001

�

4

0.0003

0.0930

0.0281

0.0374

0.0455

8

<0.0003

6

<0.0003

Molybdenum (t)

0.05

�

2

0.0022

0.0045

0.0034

0.0034

0.0016

9

<0.0005

0.0011

0.0005

0.0005

0.0003

6

<0.0005

Nickel (t)

0.02

�

15

0.0005

0.0080

0.0007

0.0013

0.0019

9

<0.0005

0.0014

0.0005

0.0007

0.0004

6

<0.0005

Selenium (t)

0.01

�

2

<0.003

0.004

<0.003

<0.003

5

<0.003

0.007

0.004

0.004

0.002

Silver (t)

0.1

�

2

<0.002

5

<0.0002

0.0006

<0.0002

<0.0002

Thallium (t)

- �

2

5

<0.0005

Vanadium (t)

- �

2

<0.003

0.006

<0.003

<0.003

<0.003

9

<0.003

0.003

<0.003

<0.003

<0.003

6

<0.003

Zinc (t)

3

�

19

<0.01

0.069

0.023

0.028

0.017

9

0.004

0.020

0.013

0.012

0.006

6

0.007

0.031

0.015

0.016

0.009

Ste

rols

(n

g/L

)

24-ethylcholestanol

- �

3

60

217

69

115

88

5

144

334

232

250

78

24-ethylcholesterol

- �

3

630

1560

809

1000

493

5

1200

2790

2140

2074

616

24-ethylcoprostanol

- �

3

<40

<80

5

108

210

158

152

42

24-ethylepicoprostanol

- �

3

<40

<80

5

<47

<67

Cholestanol

- �

3

53

216

56

108

93

5

76

147

114

117

29

Cholesterol

7000

�

3

451

1090

921

821

331

5

408

1240

908

902

314

Coprostanol

700

�

3

<40

<80

5

52

87

61

67

17

Epicholestanol

- �

3

<40

<80

5

<47

<67

Epicoprostanol

- �

3

<40

<80

5

<47

<67


water ASTR project

Page 51

Tab

le A

1-2

co

nti

nu

ed

. A

ST

R r

eed

bed

ou

tle

t (W

E2)

D

WG

M

ean

<

gu

idelin

e

2006

2007

2008

n

M

in

Max

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Tri

halo

meth

an

es f

orm

ati

on

po

ten

tial

(FP

) (µ

g/L

)

Bromoform

FP

100

�

1

<1

5

<1

1

0.5

1

0

Chloroform

FP

200

�

1

100

5

112

141

120

124

11

Dibromochloroform

FP

- �

1

27

5

<1

2

1

1

1

Dichlorobromoform

FP

- �

1

64

5

17

26

20

21

4

Trihalomethanes FP

250

�

1

131

5

129

167

147

146

14

Halo

aceti

c a

cid

fo

rmati

on

po

ten

tial

(FP

) (µ

g/L

)

Bromoacetic acid FP

0.35

�

1

1

Bromochloroacetic acid FP -

�

1

9

Bromodichloroacetic acid FP -

�

1

32

Chloroacetic acid FP

- �

1

<5

Dibromoacetic acid FP

- �

1

1

Dichloroacetic acid FP

100

�

1

4

Trichloroacetic acid FP

100

�

1

70

Org

an

ic c

hem

icals

(µ

g/L

un

less o

therw

ise s

pecif

ied

)

Caffeine

0.35

�

4

0.06

0.09

0.07

0.07

0.01

DEET

2500

�

4

0.04

0.14

0.14

0.12

0.05

Dicamba

100

�

4

0.04

0.05

0.04

0.04

0.01

Diuron

30

�

4

0.09

0.13

0.13

0.12

0.02

MCPA

35

�

4

0.1

0.27

0.23

0.21

0.07

Mecoprop

350

�

4

0.01

0.02

0.02

0.02

0.01

Metolachlor

300

�

4

<0.01

0.01

0.01

0.01

0.003

Nitroso-piperidine (ng/L) -

�

4

<10

14

<20

<20

Triclopyr

10

�

4

0.03

0.03

0.03

0.03

0

Sim

azine

5

�

7

<0.1

0.57

0.05

0.18

0.23

5

<0.1

0.76

<0.1

0.25

0.31

Detergent as M

BAS (mg/L) -

�

7

<50

100

<50

45.7

29.6

5

<50

80.0

70.0

61.0

21.3

DWG = drinking water guidelin

e, taken from Australia

n D

rinking W

ater Guidelin

es, or 2A: Augmentation of Drinking W

ater Supplies guidelin

es; (t) = total; (d) = dissolved; ND = N

ot

detected; * = number of detects N

D = N

ot detected; * = number of detects; ^ = summary statistics not possible due to the use of MPN (most probable number) technique, analysis at

CSIR

O; #

= analysis from different laboratory, using higher detection lim

it


Table A1-3 Maximum concentrations (ng/L) detected by passive samplers at the cleansing reedbed inlet (WE1)

Chemical

Maximum

concentration

2006 (ng/L)

Maximum

concentration

2007 (ng/L)

Guideline

value

(ng/L)

Diuron 416 240 30,000

Phosphate tri-n-butyl Detected* 29 500

Trifluralin 1 - 50,000

Simazine 110 150** 20,000

Atrazine 57 11 20,000

Diazinon 23 - 3,000

Terbutryn 7 - 35,000

Metolachlor 12 - 300,000

Chlorpyrifos 4 - 10,000

Oxadiazon 3 - 200,000

Propiconazol isomers 14 - 140,000-

Endosulfan sulphate 6 - 30,000

Piperonyl butoxide 4 - -

Oxyfluorfen 3.5 61 87,500

Phenanthrene 1.1 1.7 150,000

Fluoranthene 1.4 1.1 150,000

Pyrene 2.6 - 150,000

* present but not quantified.

** presence confirmed by the detection using conventional water quality monitoring.


APPENDIX 2 GROUNDWATER QUALITY DATA SUMMARY 2006-2008

Table A2-1 Ambient groundwater (RW1 RW3, IW3) quality data 2006

n Min Max Median Mean SD

Physical characteristics

Conductivity (µS/cm) 3 3620 3750 3630 3670 15.0

Temperature (°C) 3 24.4 26.9 24.7 25.5 0.4

pH (-) 3 6.88 7.00 6.88 6.88 0.07

Dissolved oxygen (mg/L) 1 0.03 0.03 0.03

Redox potential (mV SHE) 1 196 196 196

Suspended Solids (mg/L) 3 2 3 3 3 0.6

Total Dissolved Solids (mg/L, calc. by EC) 3 2010 2030 2020 2020 10.0

Turbidity (NTU) 3 20 27 27 25 4.0

True Colour (HU) 3 <1 42 <1 14 24.0

Major Ions (mg/L)

Alkalinity as CaCO3 3 250 266 265 260 9

Bicarbonate 3 305 324 323 317 11

Bromide 3 3.26 3.32 3.27 3.28 0.03

Sulfate 3 272 281 273 275 5

Chloride 3 913 926 922 920 7

Cyanide 3 <0.05

Fluoride 3 0.41 0.44 0.43 0.43 0.02

Calcium 3 130 140 136 135 5

Magnesium 3 82.4 82.9 82.5 82.6 0.3

Potassium 3 13.2 13.5 13.2 13.3 0.2

Sodium 3 495 504 504 501 5

Microbiological (cfu/100 mL)

Coliforms 3 0 14 0 5 8

E.coli 3 0 0 0 0

Enterococci 3 0 0 0 0

Thermotolerant coliforms 3 0 0 0 0

Faecal Streptococci 3 0 0 0 0

Nutrients (mg/L unless otherwise specified)

Nitrate + Nitrite as N 3 <0.005

Ammonia as N 3 0.032 0.037 0.036 0.035 0.003

Total Kjeldahl Nitrogen 3 <0.05 0.07 0.025 0.04 0.03

Total Nitrogen 3 <0.05 0.07 0.025 0.04 0.03

Filterable Reactive Phosphorus 3 <0.005 0.007 0.007 0.006 0.003

Total Phosphorus 2 0.013 0.02 0.017 0.017 0.005

Dissolved Organic Carbon 3 1.2 1.6 1.3 1.4 0.2

Total Organic Carbon 3 1.3 1.6 1.4 1.4 0.2

UV254 (cm-1) 3 0.065 0.089 0.065 0.073

Metals and metalloids (mg/L)

Aluminium (t) 3 <0.020

Arsenic (t) 3 0.010 0.011 0.011 0.011 0.001

Arsenic (s) 3 0.009 0.011 0.010 0.010 0.001

Cadmium (t) 3 <0.0005

Chromium (t) 3 <0.003

Iron (t) 3 1.49 1.61 1.52 1.54 0.06

Iron (s) 3 1.56 1.59 1.59 1.58 0.02

Lead (t) 3 <0.0005

Manganese (t) 3 0.006 0.007 0.007 0.007 0.001

Manganese (s) 3 0.006 0.007 0.007 0.007 0.001

Nickel (t) 3 <0.0005

Zinc (t) 3 0.033 0.046 0.035 0.038 0.007

(t) = total; (d) = dissolved


water ASTR project

Page 54

Tab

le A

2-2

Gro

un

dw

ate

r q

ua

lity

data

200

7-2

00

8

2007 –

flu

sh

ing

ph

ase –

IW

wells

2008 –

flu

sh

ing

ph

ase –

IW

wells

2008 –

2009 -

in

jecti

on

ph

ase –

RW

well

s

n

M

in

Max

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Ph

ysic

al ch

ara

cte

risti

cs

EC (µS/cm)

12

1156

3270

2426

2326

729

8

591

1121

891

890

181

3

413

484

464

454

37

Temperature (°C

) 12

19.8

28.7

22.2

23.7

3.2

8

18.0

23.5

21.5

21.1

2.1

3

13.1

13.6

13.3

13.3

0.3

pH (-)

12

6.93

7.85

7.46

7.39

0.32

8

7.43

8.22

7.86

7.81

0.29

3

7

7.98

7.84

7.61

0.53

DO (mg/L)

11

<0.01

0.77

0.01

0.17

0.29

8

<0.01

0.53

0.02

0.08

0.24

3

0.07

2.86

0.09

1.01

1.61

Eh (mV SHE)

11

-56

96

-32

-7.4

50

8

-236

6

-5.5

-33

82

3

-55

29

-15

-14

42

Suspended Solids

(mg/L)

10

1

5

2

3

2

4

1

2

1

1.3

0.5

3

9

48

25

27

20

Total Dissolved Solids

(mg/L, calc. by EC)

12

660

1900

1350

1348

457

8

330

610

470

480

95

3

230

260

250

247

15

Turbidity (NTU)

12

3.9

22

10

12

6.7

8

1.5

3.1

2.1

2.2

0.6

3

5.2

32

15

17

14

True Colour (H

U)

3

<1

<1

<1

2

1

2

1.5

1.5

0.7

Majo

r Io

ns (

mg

/L)

Alkalinity as CaCO

3

12

191

279

260

253

24

8

163

205

175

180

15

3

185

214

205

201

15

Bicarbonate

12

233

340

313

307

29

8

199

250

213

219

18

3

226

261

250

246

18

Bromide

3

2.97

3.11

3.11

3.06

0.08

6

0.25

0.56

0.42

0.42

0.11

3

0.11

0.13

0.13

0.12

0.01

Sulfate

12

73.2

295

199

200

66

8

31.2

86.4

58.7

58.3

17.0

3

1.8

3.6

2.7

2.7

0.9

Chloride

12

238

833

533

542

226

8

79

194

138.5

139

39

3

20

26

20

22

3

Cyanide as CN (t)

3

<0.05

Fluoride

12

0.44

0.61

0.51

0.52

0.06

8

0.60

0.68

0.62

0.63

0.03

3

0.16

0.19

0.16

0.17

0.02

Calcium

12

58.1

135

97.9

97.6

29.7

8

38.4

51.5

44.4

44.5

5.0

3

62.5

70.7

65.4

66.2

4.2

Magnesium

12

33.3

81.7

58.4

58.6

18.9

8

20.8

29.5

25

25.1

3.1

3

6.1

7.1

6.4

6.5

0.5

Potassium

12

6.4

14.2

10.2

10.3

2.6

8

4.1

6.1

5.1

5.1

0.7

3

4.9

5.3

4.9

5.0

0.2

Sodium

12

139

500

336

336

118

8

53.9

143

98.4

100

29.0

3

14.2

15.4

14.8

14.8

0.6

Mic

rob

iolo

gic

al (c

fu/1

00 m

L)

Coliform

s

11

2

1200

200

286

340

4

45

1000

424

473

499

E.coli

11

0

0

0

0

0

8

0

0

0

0

3

0

1

0

0

1

Enterococci

11

0

1

0

0

0

8

0

0

0

0

3

0

0

0

0

0

Therm

otolerant

coliform

s

11

0

0

0

0

0

8

0

0

0

0

3

0

1

0

0

1

Faecal Streptococci

11

0

1

0

0

0

8

0

0

0

0

3

0

0

0

0

0


water ASTR project

Page 55

Tab

le A

2-2

co

nti

nu

ed

. G

rou

nd

wa

ter

qu

ality

da

ta 2

007

-20

08

2007 –

flu

sh

ing

ph

ase –

IW

wells

2008 –

flu

sh

ing

ph

ase –

IW

wells

2008 –

2009 -

in

jecti

on

ph

ase –

RW

well

s

n

M

in

Max

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Nu

trie

nts

(m

g/L

un

less o

therw

ise in

dic

ate

d)


12

<0.005

0.006

0.003

0.003

0.001

8

<0.005

3

<0.0005

0.21

0.0003

0.07

0.1

Ammonia as N

12

0.024

0.048

0.03

0.032

0.007

8

0.018

0.029

0.023

0.023

0.004

3

3.4

4.6

4.4

4.1

0.6

Kjeldahl Nitrogen (t)

10

0.05

0.14

0.10

0.09

0.03

8

0.09

0.33

0.14

0.16

0.09

3

3.5

5.6

5.3

4.8

1.1

Nitrogen (t)

11

0.06

0.14

0.10

0.09

0.03

8

0.10

0.34

0.14

0.17

0.09

3

3.7

5.6

5.3

4.8

1.0

Phosphorus (s)

12

<0.005

0.006

0.003

0.003

0.001

8

<0.005

0.007

0.003

0.003

0.002

3

0.006

0.20

0.14

0.12

0.10

Phosphorus (t)

11

0.006

0.019

0.013

0.012

0.004

8

0.008

0.014

0.0105

0.011

0.002

3

0.19

0.32

0.30

0.27

0.07

Organic Carbon (d)

12

0.6

1.8

1.5

1.3

0.4

8

1.6

3.1

2.3

2.2

0.5

3

7.3

12.5

9.5

9.8

2.6

Organic Carbon (t)

12

0.7

1.8

1.5

1.3

0.4

8

1.6

2.6

2.2

2.2

0.4

3

9.5

16.7

13.3

13.2

3.6

UV254 (cm

-1)

11

0.055

0.071

0.063

0.062

0.01

8

0.02

0.05

0.0425

0.039

0.01

3

0.242

0.41

0.4

0.351

0.09

Meta

ls a

nd

meta

llo

ids (

mg

/L)

Aluminium (t)

7

<0.01

<0.020

<0.01

<0.01

7

<0.01

3

0.043

0.227

0.052

0.107

0.10

Aluminium (s)

3

0.015

0.021

0.017

0.018

0.003

Antimony (t)

4

<0.0005

0.002

0.0003

0.0007

0.001

3

<0.0005

0.001

0.0006

0.001

0.0004

Antimony (s)

3

<0.0005

0.0006

0.0003

0.0004

0.0002

Arsenic (t)

12

0.004

0.008

0.006

0.0059

0.00

8

0.004

0.006

0.005

0.005

0.001

3

<0.001

0.008

0.006

0.005

0.004

Arsenic (s)

11

0.004

0.007

0.005

0.0053

0.00

7

0.004

0.007

0.005

0.005

0.001

3

0.002

0.004

0.003

0.003

0.001

Barium (t)

9

0.018

0.049

0.025

0.029

0.010

8

0.010

0.015

0.012

0.012

0.002

3

0.033

0.042

0.038

0.038

0.004

Barium (s)

4

0.009

0.013

0.010

0.010

0.002

3

0.0313

0.0394

0.0363

0.036

0.004

Beryllium (t)

4

<0.0005

3

<0.0005

Beryllium (s)

4

<0.0005

3

<0.0005

Boron (s)

9

0.14

0.29

0.21

0.22

0.04

8

0.07

0.14

0.10

0.10

0.03

3

<0.04

0.04

0.04

0.03

0.01

Cadmium (t)

12

<0.0005

8

<0.0005

0.0007

0.0003

0.0003

0.0002

3

<0.0005

Cadmium (s)

4

<0.0005

3

<0.0005

Chromium (t)

12

<0.003

0.006

0.002

0.002

0.00

8

<0.003

0.004

0.002

0.002

0.001

3

<0.003

Chromium (s)

4

<0.003

3

<0.003

Cobalt (t)

1

<0.0005

4

<0.0005

3

<0.0005

0.0005

0.0005

0.0004

0.00000

Cobalt (s)

4

<0.0005

3

<0.0005

0.0005

0.00025

0.0003

0.0001

Copper (t)

9

<0.001

0.004

0.0005

0.0009

0.00

8

<0.001

0.001

0.0005

0.0006

0.0002

3

<0.0010

Copper (s)

4

<0.0010

3

<0.001

0.0027

0.0005

0.001

0.001

Iron (t)

12

0.45

1.13

0.72

0.77

0.25

8

0.33

0.39

0.35

0.35

0.02

3

5.4

11.0

8.7

8.4

2.8


water ASTR project

Page 56

Tab

le A

2-2

co

nti

nu

ed

. G

rou

nd

wa

ter

qu

ality

da

ta 2

007

-20

08

2007 –

flu

sh

ing

ph

ase –

IW

wells

2008 –

flu

sh

ing

ph

ase –

IW

wells

2008 –

2009 -

in

jecti

on

ph

ase –

RW

well

s

n

M

in

Max

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

n

Min

M

ax

Med

ian

M

ean

S

D

Iron (s)

11

<0.0005

0.75

0.05

0.13

0.22

8

<0.005

0.39

0.30

0.25

0.16

3

5.3

9.2

8.9

7.8

2.2

Lead (t)

12

<0.0005

0.001

0.000

0.0003

0.00

8

<0.0005

3

<0.0005

0.0009

0.00025

0.0005

0.0004

Lead (s)

8

<0.0005

8

<0.0005

0.0006

0.00025

0.0003

0.0001

3

<0.0005

Lithium (t)

9

0.0084

0.024

0.016

0.016

0.01

8

0.005

0.010

0.006

0.007

0.002

3

0.0016

0.003

0.002

0.002

0.001

Lithium (s)

4

0.005

0.007

0.006

0.006

0.0007

3

0.0016

0.002

0.002

0.002

0.0004

Manganese (t)

12

0.002

0.007

0.004

0.004

0.00

8

0.002

0.003

0.002

0.002

0.001

3

0.39

0.73

0.44

0.52

0.19

Manganese (s)

3

0.006

0.006

0.006

0.006

0.00

5

0.002

0.002

0.002

0.002

3

0.35

0.71

0.36

0.47

0.20

Mercury (t)

8

<0.0003

8

<0.0003

3

<0.0003

Mercury (s)

4

<0.0003

3

<0.0003

Molybdenum (t)

9

<0.0005

0.0014

0.0008

0.0008

0.001

8

0.0011

0.0019

0.00135

0.001

0.0003

3

<0.0005

Molybdenum (s)

4

<0.0005

3

<0.0005

Nickel (t)

12

<0.0005

8

<0.0005

3

0.0012

0.0023

0.002

0.002

0.001

Nickel (s)

4

<0.005

3

0.001

0.0012

0.0012

0.001

0.000

Selenium (t)

1

<0.003

4

<0.003

3

<0.003

Selenium (s)

4

<0.003

3

<0.003

Silver (t)

1

<0.002

4

<0.0002

0.0003

0.0001

0.0002

0.0001

3

<0.0002

Silver (s)

4

<0.0002

0.0002

0.0001

0.0001

0.0001

3

<0.0002

Thallium (t)

4

<0.0005

3

<0.0005

Thallium (s)

4

<0.0005

3

<0.0005

Vanadium (t)

9

<0.003

8

<0.003

3

0.006

0.011

0.008

0.008

0.003

Vanadium (s)

4

<0.003

3

0.003

0.006

0.005

0.005

0.002

Zinc (t)

7

0.003

0.035

0.011

0.015

0.01

7

0.007

0.023

0.012

0.014

0.01

3

0.004

0.032

0.006

0.014

0.02

Zinc (s)

7

<0.003

0.006

0.004

0.004

0.002

3

<0.003

0.003

0.0015

0.002

0.001

Tri

halo

meth

an

e F

orm

ati

on

Po

ten

tial

(FP

) (u

g/L

)

Bromoform

FP

3

<1

<1

<1

<1

Chloroform

FP

3

60

80

61

67

11

Dibromochloroform

FP

3

<1

<1

<1

<1

Dichlorobromoform

FP

3

6

8

6

7

1

Total Trihalomethane FP

3

66

88

67

74

12

Org

an

ic c

hem

icals

(µ

g/L

)

2,6-D

ichlorophenol

2

<0.1

0.11


Table A2-3 Recovered water quality (RW wells) in 2009

DWG Mean <

guideline Average RW RW1

2 Feb 09 5 Mar 09

Field Readings

Conductivity (µS/cm) - 463 362

Temperature (°C) - 13.8 16.2

pH (pH units) 6.5-8.5 � 7.31 8.19

Dissolved oxygen (mg/L) 85% 0.16 0.23

Redox potential (mV SHE) - 209 202

Physical characteristics

Conductivity (µS/cm) - 470

pH (pH units) 6.5-8.5 � 7.3 7.6

Suspended Solids (mg/L) - 9

Total Dissolved Solids (mg/L; by EC) 500 � 255

Turbidity (NTU) 5 � 6.7* 1.0

True Colour (HU) 15 � 28 26

Major Ions (mg/L)

Alkalinity as CaCO3 - 216 137

Bicarbonate - 264 167

Bromide - 0.11 0.12

Sulfate 250 � <1.5 11.4

Chloride 250 � 19.5 32

Fluoride 1.5 � 0.20 0.21

Calcium - 69.7 46.9

Magnesium - 6.6 6.3

Potassium - 5.2 4.6

Sodium 180 � 13.8 22.9

Microbiological

Coliforms (cfu/100 mL) -

E.coli (cfu/100 mL) 0 � 0 0

Enterococci (cfu/100 mL) 0 � 0

Thermotolerant coliforms (cfu/100 mL) 0 � 0 0

Faecal Streptococci (cfu/100 mL) 0 � 0

Bacteriophage (pfu/10 mL) - 0

Campylobacter (cfu/L) 0 � <4

Sulfite reducing Clostridia (cfu/100 mL) - 360

Clostridium perfringens (cfu/100 mL) 0 � <10

Cryptosporidium - Presumptive (oocysts/10 L) 0 � <9 - <12

Giardia - Presumptive (oocysts/10 L) 0 � <3

Nutrients (mg/L)

Nitrate + Nitrite as N 11.3 � <0.005 0.007

Ammonia as N 0.5 � 5.847* 0.156

Total Kjeldahl Nitrogen - 5.695*

Total Nitrogen - 5.705* 0.3

Filterable Reactive Phosphorus - 0.0065 0.022

Total Phosphorus - 0.2325* 0.035

Silica 7

Dissolved Organic Carbon - 6.5* 4.2

Total Organic Carbon - 9.5* 4.2

UV254 (cm-1) - 0.5715*


Table A2-3 continued. Recovered water quality (RW wells) in 2009

DWG Mean <

guideline Average RW RW1

2 Feb 09 5 Mar 09

Metals and metalloids (mg/L)

Aluminium (t) 0.2 � 0.023

Antimony (t) 0.003 � 0.0013

Arsenic (t) 0.007 � 0.0015 0.002

Arsenic (s) - 0.0015 0.002

Barium (t) 0.7 � 0.036

Beryllium (t) - <0.0005

Boron (s) 4 � 0.048

Cadmium (t) 0.002 � <0.0005

Chromium (t) 0.05 � 0.005

Cobalt (t) - 0.0005

Copper (t) 1 � <0.001

Iron (t) 0.3 � 5.67‡ * 0.379

Iron (s) - 5.67‡ * 0.378

Lead (t) 0.01 � <0.0005

Lead (s) -

Lithium (t) - 0.0023

Manganese (t) 0.1 � 0.331* 0.0565

Manganese (s) - 0.272* 0.0571

Mercury (t) 0.001 � <0.0003

Molybdenum (t) 0.05 � <0.0005

Nickel (t) 0.02 � 0.0014

Selenium (t) 0.01 � <0.003

Silver (t) 0.1 � <0.0002

Thallium (t) - <0.0005

Vanadium (t) - 0.006

Zinc (t) 3 � 0.01

Radiological (mBq/L)

Gross alpha activity 500

Gross beta activity (K-40 corrected) 500 � <10

Faecal sterols (ng/L)

24-ethylcholestanol - 371

24-ethylcholesterol - 533

24-ethylcoprostanol - <100

24-ethylepicoprostanol - <100

Cholestanol - 240

Cholesterol 7000 � 302

Coprostanol 700 � <100

Epicholestanol - <100

Epicoprostanol - <100

Trihalomethanes formation potential (FP) (µg/L)

Bromoform FP 100 � <1

Chloroform FP 200 � 46

Dibromochloroform FP - <1

Dichlorobromoform FP - 4.5

Total Trihalomethanes FP 250 � 50.5

Detergents (mg/L)

Detergent as MBAS 0.18

(t) = total; (d) = dissolved; * initial purging of recovery well - not considered representative of recovered water; ‡

adjusted for analytical error (reported soluble>total).


APPENDIX 3 LIST OF ORGANIC CHEMICALS ANALYSED Sampling for organic chemicals occurred in 2007 and 2008 at the Parafield stormwater harvesting system and at the ASTR well field. A total of ten samples were taken from July 2007 to August 2008 at the cleansing reedbed inlet (WE1) and eleven samples at the reedbed outlet (WE2); two samples of injectant (September 2007 and September 2008); six samples pumped from the IW wells (flushing phase, September 2007 to September 2008); and one sample from RW1 (end of flushing phase, September 2008). In February 2009, two samples were taken from the RW wells and analysed for pesticides only. All organic chemicals that were not detected anywhere in the ASTR scheme are listed in alphabetical order in Table A3-1 below. Organic chemicals that were detected are shown in Table A3-2.

Table A3-1 Organic chemicals analysed for but not detected in the ASTR scheme

Non-detected chemical Detection limit (µg/L)

1,1,1,2-Tetrachloroethane <1

1,1,1-Trichloroethane <1

1,1,2,2-Tetrachloroethane <1

1,1,2-Trichloroethane <1

1,1-Dichloroethene <1

1,1-Dichloropropene <1

1,2,3-Trichlorobenzene <1

1,2,3-Trichloropropane <1

1,2,4-Trichlorobenzene <20

1,2,4-Trimethylbenzene <1

1,2-Dibromo-3-chloropropane <1

1,2-Dibromoethane <1

1,2-Dichlorobenzene <20

1,2-Dichloroethane <1

1,2-Dichloropropane <1

1,3,5-Trimethylbenzene <1




2, 4 - DB <1

2, 4, 5 - TP <1

2, 4, 5-T <1


2,3,4,6-Tetrachlorophenol <20

2,4,5-Trichlorophenol <20

2,4,6-Trichlorophenol <20

2,4-DB <0.01

2,4-Dichlorophenol <10

2,4-Dimethylphenol <10

2,4-Dinitrotoluene <20

2,4-DP <0.01

2,6-Dichlorophenol <10

2,6-Dinitrotoluene <20

2-Butanone (MEK) <10

2-Chloronaphthalene <20

2-Chlorophenol <10

2-Chlorotoluene <1

2-Hexanone (MBK) <10

Non-detected chemical Detection limit (µg/L)

2-Methylnaphthalene <10

2-Methylphenol <10

2-Nitroaniline <20

2-Nitrophenol <10

3-& 4-Methylphenols <0.2

3&4-Methylphenol <20

3-Nitroaniline <20

4,4,'-DDD <20

4,4,'-DDE <20

4,4,'-DDT <20

4-Bromophenyl phenyl ether <20

4-Chloro-3-methylphenol <20

4-Chloroaniline <20

4-Chlorophenyl phenyl ether <20

4-Chlorotoluene <1

4-Isopropyltoluene <1

4-Methyl-2-pentanone (MIBK) <10

4-Nitroaniline <20

4-Nitrophenol <0.1

a-BHC <20

Acenaphthene <10

Acenaphthylene <10

Acetylsalicylic acid <0.01

Aldrin <20

alpha-BHC <0.01

alpha-Endosulfan <0.01

Ametryn <0.01

Aniline <20

Anthracene <10

Atenolol <0.01

Atorvastatin <0.01

Atrazine <0.1

Azinphos ethyl <0.1

Azinphos methyl <0.1

Azobenzene <20

b-BHC <20

Benz(a)anthracene <10

Benzene <1


Table A3-1 continued.

Benzo(a)pyrene <10

Benzo(b)&(k)fluoranthene <0.2

Benzo(b,k)fluoranthene <20

Benzo(g,h,i)perylene <10

Benzo(ghi)perylene <0.1

Benzyl alcohol <20

beta-BHC <0.01

beta-Endosulfan <0.01

Bis(2-chloroethoxy)methane <20

Bis(2-chloroethyl)ether <20

Bis(2-chloroisopropyl)ether <20

Bis(2-ethylhexyl) phthalate <20

Bromacil <0.01

Bromobenzene <1

Bromochloromethane <1

Bromodichloromethane <1

Bromoform <1

Bromomethane <5

Bromophos ethyl <0.1

Bupirimate <0.1

Buprofezin <0.1

Butyl benzyl phthalate <10

Carbamazepine <0.01

Carbazole <20

Carbon disulfide <10

Carbon tetrachloride <1

Carbophenothion <0.1

Cephalexin <0.01

Chloramphenicol <0.1

Chlorfenvinphos (E) <0.1

Chlorfenvinphos (Z) <0.1

Chlorobenzene <1

Chloroethane <5

Chloroform <1

Chloromethane <5

Chlorothalonil <0.1

Chlorpyrifos <20

Chlorpyrifos methyl <0.1

Chlortetracycline <0.1

Chrysene <10

Ciprofloxacin <0.01

cis-1,2-Dichloroethene <1

cis-1,3-Dichloropropene <1

cis-Chlordane <0.01

Citalopram <0.01

Codeine <0.1

Coumaphos <0.1

Cyprodinil <0.1

Dalapon <0.01

Dapsone <0.01

d-BHC <20

delta-BHC <0.01

Demeton-S-methyl <0.1

Desethyl Atrazine <0.01

Desmethyl Citalopram <0.01

Desmethyl Diazepam <0.01

Diazepam <0.01

Diazinon <20

Dibenz(a,h)anthracene <10

Dibenz(ah)anthracene <0.1

Dibenzofuran <20

Dibromochloromethane <1

Dibromomethane <1

Dichlofluanid <0.1

Dichlorobenzidine <20

Dichloromethane <1

Dichlorprop <1

Dichlorvos <0.1

Diclofenac <0.01

Dicloran <0.1

Dicofol <0.1

Dieldrin <20

Diethyl phthalate <10

Difenoconazole <0.1

Dimethoate <20

Dimethomorph <0.1

Dimethyl phthalate <10

Di-n-butyl phthalate <10

Di-n-octyl phthalate <10

Dioxathion <0.1

Diphenylamine <0.1

Doxylamine <0.01

Endosulfan sulfate <0.01

Endosulfan sulphate <20

Endosulphan I <20

Endosulphan II <20

Endrin <20

Endrin Aldehyde <20

Endrin Ketone <0.01

Enrofloxacin <0.01

Erythromycin <0.01

Ethion <20

Ethylbenzene <1

Fenamiphos <0.1

Fenarimol <0.1

Fenchlorphos <0.1

Fenitrothion <20

Fenthion <0.1

Fluoranthene <10

Fluorene <10

Fluoxetine <0.01

Fluroxypyr <0.01

Flusilazole <0.1

Fluvastatin <0.01

Formothion <0.1

Frusemide <0.01

Gabapentin <0.01


gamma-BHC(Lindane) <0.01


g-BHC (Lindane) <20

Gemfibrozol <0.01

HCB <0.01

Heptachlor <20

Heptachlor epoxide <0.01

Heptachlorepoxide <20

Hexachloro-1,3-butadiene <20

Hexachlorobenzene <20

Hexachlorobutadiene <1

Hexachlorocyclopentadiene <20

Hexachloroethane <20

Hexaconazole <0.1

Hexazinone <0.1

Hydrochlorthiazide <0.01

Ibuprofen <0.01

Imazalil <0.1

Indeno(1,2,3-cd)pyrene <10

Indomethacin <0.01

Iopromide <0.2

Iprodione <0.1

Isophorone <20

Isopropylbenzene <1

Lincomycin <0.01

Linuron <0.1

m & p-Xylenes <2

Malathion <20

MCPB <0.01

MCPP <1

Metalaxyl <0.1

Methacrifos <0.1

Methidathion <0.1

Methoprene <0.1

Methoxychlor <0.01

Metoprolol <0.01

Mevinphos <0.1

Molinate <0.1

Naphthalene <10

Naproxen <0.1

n-Butylbenzene <1

NDBA <0.02

NDEA <0.01

NDMA <0.005

Nitrobenzene <20

Nitroso-pyrrolidine <0.01

N-Nitrosodimethylamine <20

N-Nitrosodi-n-propylamine <20

N-Nitrosodiphenylamine <20

Norfloxacin <0.01

n-Propylbenzene <1

o-Phenylphenol <0.1

Oxazepam <0.01

Oxychlordane <0.01

Oxycodone <0.01

Oxyfluorfen <0.1

o-Xylene <1

Oxytetracycline <0.1

p,p-DDD <0.01

p,p-DDE <0.01

p,p-DDT <0.01

Parathion (ethyl) <0.1

Parathion methyl <0.1

Penconazole <0.1

Pendimethalin <0.1

Pentachlorophenol <20

Phenanthrene <10

Phenol <10

Phenytoin <0.01

Phorate <0.1

Phosalone <0.1

Picloram <0.01

Piperonyl Butoxide <0.1

Pirimiphos ethyl <0.1

Pirimiphos methyl <0.1

Praziquantel <0.01

Prochloraz <0.1

Procymidone <0.1

Profenophos <0.1

Prometryn <0.01

Propargite <0.1

Propiconazole I <0.1

Propiconazole II <0.1

Propranolol <0.01

Prothiofos <0.1

Pyrene <10

Pyrimethanil <0.1

Ranitidine <0.01

Roxithromycin <0.01

Salicylic acid <0.01

sec-Butylbenzene <1

Sertraline <0.01

Simvastatin <0.01

Styrene <1

Sulfsalazine <0.01

Sulphadiazine <0.01

Sulphamethoxazole <0.01

Sulphathiazole <0.01

Tebuconazole <0.1

Tebufenpyrad <0.1

Tebuthiuron <0.01

Temazepam <0.01

Terbutryn <0.01

tert-Butylbenzene <1

Tetrachloroethene <1

Tetracycline <0.01

Tetradifon <0.1

Thiometon <0.1

Toluene <1


Tramadol <0.01


trans-1,2-Dichloroethene <1

trans-1,3-Dichloropropene <1

trans-Chlordane <0.01

Triazophos <0.1

Trichloroethene <1

Trichlorofluoromethane <5

Triclosan <0.01

Trifluralin <0.1

Trimethoprim <0.01

Tylosin <0.01

Venlafaxine <0.01

Vinclozolin <0.1

Vinyl chloride <2

Vinylacetate <10

Warfarin <0.01

Table A3-2 Organic chemicals detected in the ASTR scheme

WE1 WE2 IW –

flushing phase

RW1 – end of

flushing phase

RW – recovered

Detected chemical

number of detects / number of analyses

2,4-D 1 / 2

2,6-Dichlorophenol 1 / 2

Bis(2-ethylhexyl) phthalate 1 / 10

Caffeine 4 / 4 4 / 4

DEET 4 / 4 4 / 4 1 / 1

Desisopropyl Atrazine 3 / 4 0 / 4

Detergent as MBAS 9 / 10 7 / 11 1 / 1 2 / 2

Dicamba 2 / 4 4 / 4 1 / 2

Dichloromethane 1 / 10

Diuron 4 / 4 4 / 4 1 / 2

Fluometuron 1 / 1

MCPA 4 / 4 4 / 4 1 / 2

Mecoprop 4 / 4 4 / 4

Metolachlor 1 / 4 3 / 4

Nitroso-piperidine 3 / 4 1 / 4

Paracetamol 4 / 4 0 / 4

Simazine 4 / 10 4 / 11

Triclopyr 4 / 4 4 / 4 1 / 2


APPENDIX 4 SUMMARY OF REVISED MONITORING SUITE Table A4-1 Recommended revised monitoring suite

General Metals (total) Organic chemicals

conductivity (in situ) aluminium (plus dissolved) Atrazine

pH (in situ) arsenic (plus dissolved) BTEX

DO (in situ) barium Caffeine

Eh (in situ) boron Chlorpyrifos

temperature (in situ) cadmium DEET

suspended solids chromium Desisopropyl Atrazine

alkalinity copper Detergents

colour Iron (plus dissolved) Diazinon

turbidity lead Dicamba

manganese Diuron

Microbiological nickel Endosulfan sulphate

E. Coli silica Fluometuron

thermotolerant coliforms zinc MCPA

Campylobacter jejuni Major Ions Mecoprop

Cryptosporidium parvum calcium Metolachlor

rotavirus magnesium Nitroso-piperidine

potassium Oxadiazon

Nutrients bromide Paracetamol

ammonia as N sodium Phosphate tri-n-butyl

nitrate + nitrite as N bicarbonate Piperonyl butoxide

total nitrogen chloride Propiconazol isomers

total phosphorus fluoride Simazine

filterable reactive phosphorous sulfate Terbutryn

total organic carbon Triclopyr

dissolved organic carbon Trifluralin


APPENDIX 5 REVISED QUANTITATIVE MICROBIAL RISK ASSESSMENT

Quantitative microbial risk assessment (QMRA) of recycled water systems requires the quantification of pathogen occurrence in source water and their removal through the various treatment barriers. When pathogen occurrence is combined with exposure scenarios and pathogen dose-response relationships, the risk to human health can be estimated.

The end point of the human health risk assessment used in this report was expressed as Disability Adjusted Life Years (DALYs). DALYs have been used extensively by agencies such as the World Health Organization (WHO) to assess disease burdens and to identify intervention priorities associated with a broad range of environmental hazards (WHO 2004).One DALY per million people a year roughly equates to one cancer death per 100 000 in a 70 year lifetime (a benchmark often used in chemical risk assessments) [WHO, 2004]. The DALY is calculated as the product of the probability of each illness outcome with a severity factor and the duration (years). The advantage of using DALYs over an infection risk end point is that it not only reflects the effects of acute end-points (e.g. diarrhoeal illness) but also the likelihood and severity of more serious disease outcomes (e.g. Guillain-Barré syndrome associated with Campylobacter).

The general framework for estimating pathogen risks used in this report is based on the approach described in the Australian Guidelines for Water Recycling (2006) and is based on the QMRA previously developed by Page et al. (2008). The hypothesis to be tested for each reference pathogen was that risk attributable to drinking water from the ASTR system resulted in a disease burden of 1×10-6 DALYs per year or less.

QMRA Methodology

QMRA typically incorporates the following steps (AGWR 2006):

1. Hazard identification - identification of the pathogens and the associated disease burden on human health; this step also includes consideration of variability in pathogen concentrations.

2. Dose-response - the relationship between the dose of the pathogen and the likelihood of illness.

3. Exposure assessment - determination of the size and nature of the population exposed to the hazard, and the route, volume and duration of exposure.

4. Risk characterisation - integration of data on hazard presence, dose-response and exposure, obtained in the first three steps.

Hazard Identification

The scope of the assessment was limited to three "index" pathogens, representing the three microbiological groups: bacteria, protozoa and viruses as described by AGWR (2006): Campylobacter; Cryptosporidium parvum and rotavirus respectively. These pathogens were selected as they are known to be present in sewage and contribute the greatest population health burden in terms of DALYs. To date none of the reference pathogens have been detected in the source stormwater.

Dose-response

Information on relationships between doses of pathogens and incidence or likelihood of illness is generally obtained from investigations of outbreaks or from experimental human-


feeding studies (WHO 2004). The ingestion dose–response models and the DALYs per infection used in this report for the hazards identified above are extensively detailed in the Australian Guidelines for Water Recycling (2006).

Exposure assessment

The main route of exposure to microbial hazards is drinking; this report uses the same exposure assumptions as the Australian Drinking Water Guidelines (NHMRC 2004), i.e. 2 L per person per day at a frequency of 365 days per year.

Risk Characterisation

The last step in risk assessment is to integrate information from hazard identification, dose response and exposure assessment, to determine the magnitude of risk. In all cases, the variables in determining the magnitude of risk for the reference pathogens are concentrations of the organisms and exposure. The conceptual model underpinning this risk assessment assumes that pathogens contained in Parafield stormwater are passed through the in-stream basin, holding storage and cleansing reedbed before being injected into the aquifer. Water is then recovered from the ASTR well field with post-treatment including UV and chlorination disinfection prior to the mains as suggested by Toze et al. (2009). This model has a number of assumptions (Table A5-1) associated with the initial pathogen concentrations (NRMMC-EPHC in prep), pathogen decay rates in the cleansing reedbed and the subsurface (Toze et al. 2008; 2009) and travel times between injection and recovery wells estimated by groundwater modelling (Kremer et al. 2008).


Table A5-1 Stochastic parameters used in Monte Carlo simulation

Factor Distribution

type Mean, SD Reference

Campylobacter numbers in stormwater (n/L) Log-normal 3.3, 1.9†

EPHC–NHMRC–NRMMC

(2008c)

Cryptosporidium numbers in stormwater (n/L) Log-normal 0.5, 1.2†


(2008c)

Rotavirus numbers in stormwater (n/L) Log-normal 0.3, 0.7†


(2008c)

Campylobacter decay rate (Reedbed, log/day)* Normal 0.20, 0.020 Toze et al. (2008)‡

Cryptosporidium decay rate (Reedbed, log/day) Normal 0.013, 0.0023 Toze et al. (2008)‡

Rotavirus decay rate (Reedbed, log/day)** Normal 0.031, 0.0029 Toze et al. (2008)‡

Campylobacter decay rate (Aquifer, log/day) n/a 5.6*** Toze et al. (2009)‡ ‡

Cryptosporidium decay rate (Aquifer, log/day) Normal 0.012, 0.0030 Toze et al. (2009)‡ ‡

Rotavirus decay rate (Aquifer, log/day) Normal 0.0055, 0.0036 Toze et al. (2009)‡ ‡

Reedbed residence time (days) Normal 11.7, 1.5 Page et al. (2008)

Aquifer residence time (days) Log-normal 241, 58 Kremer et al. (2008)

Chlorination (log) Triangular 2, 1 EPHC–NHMRC–NRMMC

(2008a)

UV n/a 3.0*** EPHC–NHMRC–NRMMC

(2008a)

n/a not applicable † 95

th Percentile as per Table A3.1 of the Draft Guidelines for Stormwater Harvesting and Reuse: Campylobacter

15 n/L; Cryptosporidium 1.8 n/L; rotavirus 1 n/L (NRMMC-EPHC in prep). ‡ diffusion chamber studies were performed for a 48 day period from 22/07/08 through to 01/09/08.

‡‡ diffusion chamber studies were performed for a 35 day period from 13/11/09 through to 16/12/09

* value cited is for Salmonella ** value cited is for adenovirus *** single mean value only

The Australian Guidelines for Water Recycling (2006) define a tolerable level of risk as <10–6

DALYs per person per year. Table A5-2 provides an example risk characterisation used in this report.


Table A5-2 Example QMRA calculation for rotavirus

Parameter Value Comment

Initial concentration in stormwater (n/L)

1.4 × 10-4 Sampled from range of rotavirus numbers from Table A5-1.

Residence time in the reedbed (days)

12.4 Sampled from range of reedbed residence times from Table A5-1.

Decay rate in reedbed (log/day) 0.03 Sampled from range of reedbed decay rates from Table A5-1.

Total log removal in reedbed (log) 0.42 Calculated using decay rate of 0.03 log/day

Residence time in the aquifer (days)

239 Sampled from range of aquifer residence times from Table A5-1.

Decay rate in aquifer (log/day) 0.0055 Sampled from range of aquifer decay rates from Table A5-1.

Total log removal in aquifer (log) 1.3 Calculated using decay rate of 0.055 log/day

Final concentration in recovery well (n/L)

2.5 × 0-6 Calculated from initial concentration and log removal

UV disinfection (log) 3 Based on EPHC–NHMRC–NRMMC (2008a)

Chlorination 2.35 Based on EPHC–NHMRC–NRMMC (2008a)

Final dose (n) 1.1 × 10-11 Calculated dose assuming 2L per day

Risk of infection (ρinf) 2.5 × 10-9

Calculated from beta-Poisson dose response curve (NRMMC–EPHC–AHMC 2006) at 364 exposures per year

DALYs 2.1 × 10-11 Risk characterised as using a DALYs / infection of 1.4 ×10

-2

The example shown in Table A5-2 applies a deterministic approach, using single-point estimates for pathogen concentrations, residence times, decay rates, exposure volume and numbers of exposure events. Each single point estimate is drawn at random from its distribution (given in Table A5-1).This is repeated 10,000 times in Monte Carlo simulations to provide a stochastic analysis that addresses variability and uncertainty to produce an estimate of the risk.

QMRA Simulation settings

The QMRA models were developed to facilitate Monte Carlo simulation, which entails generating hypothetical scenarios in terms of the values attributed to the factors in the exposure and dose-response assessments. The simulation represents the inherent variability in the process of initial pathogen concentrations, transport and decay and influence on expectant risk as well as the uncertainty in the mathematical model of the process. Ten thousand iterations were performed for each simulation, using Latin Hypercube sampling, with @RISK Industrial v4.5 [Palisade, Newfield, NY] and Microsoft Excel [Microsoft Corp., CA] software. The outcome is a statistical distribution of risk experienced by the diverse members of the population expressed as the mean, median, 95th percentile and maximum values.

QMRA Results

The risk characterisation results for each of the reference pathogens are shown in Table A5-3, values which exceed the upper limit of 10–6 DALYs per person per year are shown in bold.

Table A5-3 Risk Characterisation results (DALYs)

Pathogen Mean Median 95th

percentile Maximum

Campylobacter << 1 × 10-10 << 1 × 10

-10 << 1 × 10

-10 << 1 × 10

-10

Cryptosporidium 2.8 × 10-8 2.5 × 10

-11 1.1 × 10

-8 1.7 × 10

-4

rotavirus 3.0 × 10-7

3.1 × 10-11

6.6 × 10-8

8.4 × 10-4


Rotavirus was the highest risk pathogen. The mean, median and 95th percentile values for the human health risks from Campylobacter, Cryptosporidium and rotavirus were acceptable

(< 1.0 × 10-6 DALYs). This could be attributed to the high decay rate of Campylobacter in the subsurface (~5 log/day) and the low initial numbers of Cryptosporidium and rotavirus in the stormwater coupled with post-recovery treatment. The 95th percentile can be used as a measure of the robustness of the mean human health risk assessment. Where both the mean and the 95th percentile are acceptable risk it can be determined that the risk assessment is reasonably robust.

The 95th percentile values indicate that human health risks from Campylobacter,

Cryptosporidium and rotavirus were acceptable (< 1.0 × 10-6 DALYs). The maximum risk for Cryptosporidium and rotavirus was unacceptable indicating the importance of the functioning barriers.

QMRA Sensitivity Analysis

QMRA coupled with stochastic Monte Carlo simulations can provide a sensitivity analysis of the factors that most significantly influence risk, i.e. those stochastic factors which are highly correlated with increased or decreased risk in Table A5-3. This analysis helps prioritize risk management efforts and for subsequent improvement of the QMRA model by focusing research priorities.

A sensitivity analysis was performed by repeating the risk assessment and varying only one factor (e.g. aquifer residence time) by 10% at a time whilst fixing all others at their most likely value to give a new result in DALYs. No sensitivity analysis could be performed for Campylobacter as the mean risk was estimated to be below the guideline value for all values. This precludes a detailed sensitivity analysis as all calculated risks in the Monte Carlo analysis were low. This is due to the high decay rates of bacteria in the cleansing reedbed and the aquifer. The results of the sensitivity analysis for Cryptosporidium and rotavirus are shown in Table A5-4.

Table A5-4 Sensitivity analysis of microbiological hazards

Factor Factor base value

(Cryptosporidium)

Factor base value

(rotavirus) Cryptosporidium rotavirus

Initial pathogen numbers

in stormwater (n)* 0.5 0.3 +10% +10%

Reedbed decay rate

(log/day) 0.02 0.03 -3% -5%

Reedbed residence time

(days) 11.7 11.7 -3% -5%

Aquifer decay rate

(log/day) 0.01 0.01 -37% -10%

Aquifer residence time

(days) 240 240 -37% -10%

Chlorination disinfection

efficiency (log) 0.25 2.0 -5% -23%

* Base value chosen has a 95th percentile equivalent to Cryptosporidium 1.8 n/L, rotavirus 1 n/L (NRMMC-EPHC

in prep).

Table A5-4 illustrates the change in resultant risk with a 10% increase in a factor from its base value. For Cryptosporidium the residence time in the aquifer and the associated decay rate were found to be the most important factors affecting risk. This demonstrates the importance of the role that observation bores will play in managing the ASTR system in measurement of residence times for hazards and confirmation of the pathogen decay rates


both by monitoring and through diffusion chamber experiments (Toze et al. 2009). The second most important factor for Cryptosporidium was the initial pathogen numbers in the source water, reinforcing the importance of water quality monitoring especially of potential hazardous first flush events such as storms which potentially carry the poorest quality stormwater (Page et al. 2008). Processes in the constructed reedbed and the poor efficiency of chlorination for Cryptosporidium removal (NRMMC–EPHC–AHMC 2006) indicate that these factors are less sensitive.

For rotavirus the single most important factor affecting risk was the efficiency of the post-treatment chlorination process. Chlorination disinfection efficiency has a large impact on rotavirus numbers. Chlorination was followed by the sensitivity of the residence time in the aquifer and aquifer decay rates; also having a negative correlation on risk. Similarly, the initial rotavirus concentration had a similar sensitivity to the aquifer residence time and decay rate but increasing risk. The residence time in the reedbed and the reedbed decay rates were the least sensitive factors.


APPENDIX 6 HYDROGEOCHEMICAL EVALUATION

It is necessary to develop an understanding of the dominant hydrogeochemical reaction processes that can impact on water quality during ASTR. It is possible for reactions to occur between the source water and the ambient groundwater at the water-water interface, but predominantly between the source water and the sediments within the storage zone (water-rock).

This hydrogeochemical evaluation was undertaken by considering the reaction scenarios that could occur when the ASTR source water is injected into the storage zone. It is based on evaluation of the end-members involved in reactions; the aquifer sediments, the ambient groundwater and the source water. The available groundwater monitoring data was also used to understand the dominant reaction processes.

Methodology

Characterisation of the sediment within the storage zone was based on the analysis of intact cores of aquifer material, which were collected on 3/7/2008 between depths of 163.2 and 189.4 m below ground surface (bgs). These cores were purged with nitrogen gas and stored in sealed PVC tubes at 4°C. Twelve sub-samples of the aquifer material were collected under anaerobic conditions on 5-6/2/2009 for characterisation of the physico-chemical and mineralogical properties of the T2 aquifer.

The PHREEQC modelling software (Parkhurst and Appelo 1999; version 2.15.0) was used to assess equilibrium reaction processes as follows:

• The dominant mineral phases present in the T2 aquifer influencing the ambient groundwater geochemistry using the EQUILIBRIUM PHASES subroutine;

• Potential for reaction between the source water and the mineral phases present in the T2 aquifer using the EQUILIBRIUM PHASES subroutine; and

• Mixing between the source water and the ambient groundwater in the T2 aquifer using the MIX subroutine.

The default Phreeqc.dat thermodynamic database was used to determine the ionic speciation and saturation indexes (with respect to the full suite of default minerals).

The PHREEQC simulations undertaken examine the potential for equilibrium processes, but not the redox processes which can be induced by the sources waters containing oxygen or organic matter. The potential for redox processes to mobilise iron and arsenic and impact on the recovered water can be examined with decision trees developed in the draft MAR Guidelines (EPHC-NHMRC–NRMMC 2008a).

Two possible source waters were considered; urban stormwater following reedbed treatment (WE2) and urban stormwater following reedbed treatment and aquifer storage and recovery (ASR).

Despite being in the early stages of the subsurface component of the ASTR trial, the available groundwater monitoring data was used to understand water quality changes as outlined below:

• IW well (IW1 1/9/2008) at the end of the flushing phase was used to examine the water quality changes after aquifer passage.

• RW well (RW1) during the injection phase was used to evaluate water quality changes after 3 months (2/9/2008) and 8 months (2/2/2009) of aquifer storage. As this well had been used for injection during the flushing phase, the water quality was expected to represent storage in a nutrient rich zone.


• RW well (RW1) after recovery of approximately 16 ML from this well (5/3/2009) represents water quality after aquifer storage transfer and recovery without the influence of the nutrient rich zone around the point of injection.

Chloride was used to quantify the end-member contributions and as the basis for mass balance calculations in groundwater sampled from IW1 on 1/9/2008.

End-members

Aquifer characterisation

X-Ray Diffraction (XRD) and X-Ray Fluorescence were used to quantify the major mineral phases (Table A6-1) and major (Table A6-2) and minor (Table A6-3) elemental composition in the 12 samples of aquifer core material. The mineralogy is dominated by carbonate minerals, predominantly as calcite (64%) with some evidence of ankerite and siderite, and quartz (30%).There are minor contributions from hematite, goethite, pyrite, albite and microcline.

Carbonate and iron mineral phases within the sediments are important reactive phases during Managed Aquifer Recharge. Carbonate minerals are important influences on the recovered water quality as equilibrium between the source water and the mineral phase can be reached rapidly. Iron is present within various reactive phases in the aquifer sediments. Pyrite can be oxidised by oxygenated source water, while hematite and goethite are susceptible to reductive iron dissolution when organic matter is present in the source water.

These analyses indicate that the aquifer sediments are a source for a number of elements (Al, As, Ba, Cr, Cu, Fe, Mn, Mo, Ni, Zn) that are considered in the Australian Drinking Water Guidelines.

Ambient groundwater

The three samples of ambient groundwater in the T2 aquifer collected in June 2006 (RW1, RW2 and IW1) exhibit similar chemical composition. The sample collected from RW2 on 22/6/06 was used to represent the ambient groundwater for the PHREEQC simulations (Table A6-6) as this sample has data for pH, temperature, dissolved oxygen and redox potential measured in-situ with calibrated equipment necessary to understand the hydrogeochemical environment within the aquifer.

The calculated saturation indices indicate the ambient groundwater is in equilibrium with carbonate minerals, calcite, dolomite and siderite, sub-saturated with respect to gypsum and amorphous aluminium hydroxide and super-saturated with respect to amorphous iron hydroxide, goethite and gibbsite (Table A6-7). Aqueous silica concentrations were not available for the ambient groundwater, thus preventing the quartz saturation index from being examined. Thus the mineral phases influencing the ambient groundwater quality correspond with the phases identified during characterisation of the aquifer core samples.

Source water

Two source waters were used for the evaluation of hydrogeochemical processes. The mean quality from the outlet of the cleansing reedbed (WE2) between 2006 and 2008 was used to represent urban stormwater following reedbed treatment. A sample collected from Parafield ASR Production Well 2 (ASR PW2) on 30/4/2007 was used to represent urban stormwater following reedbed treatment and aquifer storage and recovery (ASR) (Table A6-6). This sample represents the groundwater quality that was distributed as bottled water.

Water exiting the reedbed (WE2) is oxygen-rich and predominantly cooler than the anoxic storage zone. In contrast, the source water with the additional treatment of ASR is devoid of oxygen and warmer, with a temperature intermediate to that of the reedbed source water and the receiving groundwater. The source waters are lower in iron content than the ambient groundwater, but they are a source of nutrients, in particular organic carbon.


Mineral equilibrium and mixing

The mineral saturation indexes give an indication of their potential for precipitation or dissolution of mineral phases when the source water is introduced to the storage zone (Table A6-7).

Urban stormwater exiting the reedbed (WE2) is sub-saturated with respect to carbonate minerals and therefore introduction of WE2 source water to the T2 aquifer will result in dissolution of carbonate mineral phases (mainly present as calcite). The effect on water quality would be an increase in calcium, bicarbonate (and alkalinity), magnesium (Mg-substituted calcite) and the pH will remain close to neutral. In contrast the ASR PW2 source water is near to equilibrium with the carbonate minerals as it has already been stored in the T2 aquifer. In essence, the major ion chemistry resulting from reedbed treated stormwater reaching equilibrium with the T2 aquifer during ASTR will be similar to the quality following ASR.

It follows that a mixture of the ambient groundwater with the WE2 source water, which may occur on the fringe of the injected plume, will be slightly less aggressive towards the mineral phases in the storage zone (Table A6-7).

Precipitation of metal oxides, such as amorphous iron and aluminium hydroxides, could result in aquifer clogging. The sources waters are sub-saturated with respect to aluminium hydroxides and thus these would not be expected to precipitate during aquifer storage. However the iron oxide phases are super-saturated and would be expected to precipitate in the storage zone.

Metal mobilisation

Following the decision trees in the draft MAR Guidelines (EPHC-NHMRC–NRMMC 2008a) indicates the potential for release of both arsenic and iron at the ASTR site when reedbed treated stormwater (with and without ASR treatment step) is introduced into the T2 aquifer. Iron is present in both oxidised (goethite, hematite) and reduced (pyrite) forms in the aquifer sediments, which indicates two possible pathways for mobilisation of iron into solution, both of which can also lead to increased arsenic concentrations. In this case the release via reduction dissolution of iron oxides has been highlighted in Figures A6-1 and A6-2 as hematite and goethite were detected more frequently in aquifer core samples than pyrite. However, this should not discount the possibility of release through pyrite oxidation, but this is more likely around the points of injection following the introduction of oxygenated source water.

The potential for mobilisation via either pathway is reduced with the ASR PW2 source water. The organic carbon concentration following ASR is lower than the WE2 source water, but remains greater than that of the ambient groundwater. In addition oxygen is removed during ASR, and thus the source water oxygen concentration will remain low unless it is oxygenated (e.g. by passage through the reedbed) prior to use at the ASTR site.

Observed water quality changes

These processes can be examined after aquifer passage in the water quality from IW1 at the end of the flushing phase and also after a period of aquifer storage in the water quality from RW1.

Based on the chloride signature of the end-members, the sample collected from IW1 at the end of the flushing phase (1/9/2008) was a mixture of approximately 88% reedbed treated urban stormwater (WE2) and 12% ambient groundwater. Mass balance calculations indicate that concentrations of bicarbonate, calcium, magnesium, sodium and sulfate in IW1 were greater than expected from mixing alone, thus indicating a gain during injection. Organic carbon, nitrogen, phosphorus and iron concentrations were all lower than expected through mixing and thus represent a loss during injection.


The water quality in IW1 appears to be influenced by equilibrium with carbonate minerals which results in addition of calcium, magnesium and bicarbonate when magnesium substituted calcite (simulated as calcite and dolomite) dissolves (Table A6-7). Some precipitation of the less soluble carbonate mineral, siderite, can lead to a reduction in the soluble iron concentration.

Carbonate equilibrium alone does not account for all the water quality changes observed at IW1. The bicarbonate increase exceeds that expected from carbonate dissolution alone and may also be produced by removal of organic matter via oxidation. Mass balance calculations indicated a 3 mg/L reduction in DOC at IW1, believed to be achieved through oxidation (consistent with oxygen consumption) and sorption. A slight increase in sodium between injection and IW1 suggests some release of sodium through cation exchange with calcium, which would mask some of the calcium increase via carbonate dissolution.

It must be noted that these observations are along a single-flow path during the initial pore flush and reactivity can reduce with subsequent pore-flushes. Cation exchange has been shown to alleviate after a small number of pore flushes (Stuyfzand 1998).

The water quality data for the two piezometers in the ASTR storage zone (P1 and P2, 166-169 mg bgs) indicated super-saturation with the carbonate and iron oxide minerals after the flushing phase had ceased (16/10/2008) (Table A6-7). The deeper P3 (210-215 m bgs) remained closer to equilibrium with the carbonate minerals.

The water quality in RW1 did not change considerably between 3 months (2 September 2008) and 8 months (2 February 2009) of aquifer storage (Table A6-6). Here the concentrations of manganese, iron, ammonia and phosphorus exceeded those within the source water, while sulfate was lower than in the source water. These changes can be explained by mineralisation of accumulated organic matter during the storage phase. Manganese, iron and sulfate are progressively utilised as electron acceptors while nitrogen and phosphorus are released during organic matter oxidation. These observations disagree with the observed reduction of nitrogen, phosphorus and iron along the injection flow-path to IW1. However, the water quality from RW1 represents a nutrient rich zone around the point of injection. While it is not typical of the water quality in the bulk of the storage zone this zone can play an important role in biodegradation of organic chemicals under reducing conditions. There is no evidence for arsenic release resulting from the reductive iron dissolution in RW1 during this period of aquifer storage.

Preliminary water quality data for RW1 (5 March 2009) following recovery of approximately 16 ML from this well, indicates lower manganese, iron, and ammonia concentrations which are more likely to represent the bulk quality of water stored in the aquifer (Table A6-6). In addition the water quality sampled from RW1 in March 2009 indicates super-saturation with respect to both the carbonate and the iron oxide minerals (Table A6-7). The water quality recovered from RW1 after recovery remains above the aesthetic guideline value of 0.3 mg/L for Australian Drinking Water (NHMRC-NRMMC 2004).

Aquifer dissolution

The impacts of aquifer dissolution on the lifetime of an injection well can be examined by considering the stability of the overlying aquitard. Carbonate dissolution occurs soon after injection around the point of injection. Therefore, we can consider that the diameter of the open interval will increase with time, to a point where it is not able to support the overlying aquitard. The impact of aquifer dissolution on the stability of the overlying clay aquitard was considered by assuming that dissolution of a 2 m radius around the injection well would result in stability concerns.

For a well with an open interval of 20 m, a 2 m radius around the well contains approximately 260 T of calcite (total aquifer volume 250 m3 using a porosity of 0.45, bulk density of 1.5 g/cm3 and average calcite content of 70%).

At this stage in the ASTR trial, the amount of calcite dissolution that occurs is not certain. The calcium and magnesium excess observed in groundwater sampled from IW1 on


1/9/2008 indicate 0.2-0.5 mmol/L of dissolution, while equilibrium modelling with PHREEQC suggests 0.3 mmol/L dissolution. Dissolution rates of 0.3 and 0.5 mmol/L were considered in this evaluation of the impacts of aquifer dissolution.

The annual injection volume is dependent on the availability of the seasonally variable source water. Kremer et al. (2008) considers injection volumes of 104, 173 and 300 ML/year as estimates of injection volumes in dry, normal and wet years. A ‘normal’ year is suitable for examining the long-term impacts of aquifer dissolution over the lifetime of an injection well and equates to 43 ML/year in each of the four IW wells. The time required to dissolve the calcite in a 2 m radius around an injection well is estimated at 200 years at a dissolution rate of 0.3 mmol/L, and around 120 years at the faster dissolution rate of 0.5 mmol/L.

These calculations indicate aquifer dissolution is not a risk to the lifetime of the IW wells. However the aquifer dissolution rate needs to be determined in the proximity of the injection well using the behaviour between IW1 and P1 during an injection phase.


Table A6-1 Mineralogy of the T2 aquifer core samples

Quartz Calcite1 Aragonite

Ca-Dolomite/ Ankerite

2

Hematite Goethite Pyrite Albite Microcline Siderite3 Depth

(m bgs)

Sample ID

(%)

163.9 1 4.1 91.8 1.5 2.3 0.4

164.6 2 8.5 86.1 1.6 3.5 0.2

166.5 4 8.7 82.8 1.7 6.6 0.3

166.9 5 5.8 88.7 0.8 4.6 0.2

171.0 11 58.1 35.0 0.4 0.9 0.7 2.2 0.7 1.9

173.8 14 14.8 83.7 0.2 0.2 0.3 0.8

176.3 18 49.4 43.6 0.9 0.6 0.5 1.1 0.7 1.1 2.2

177.9 20 31.3 63.0 1.5 0.4 0.3 0.6 0.5 0.7 1.6

179.6 22 39.3 55.6 0.6 0.6 0.4 0.8 0.4 0.9 1.6

182.9 25 19.2 75.7 0.9 1.9 0.6 0.6 0.2 0.9

185.7 27 63.3 26.3 2.9 0.9 0.3 1.7 1.5 2.1 0.8

189.3 29 51.2 43.0 0.4 0.3 0.4 1.9 1.0 1.9

Min 4.3 26.3 0.2 0.2 0.2 0.6 0.4 0.2 0.8 0.8

Max 63.3 91.8 2.9 6.6 0.7 2.2 0.7 1.5 2.2 0.8

Mean 29.5 64.6 1.1 1.9 0.4 1.3 0.5 0.9 1.6 0.8 1 Calcite is magnesium substituted

2 Siderite is tentatively identified in sample 27 due to a single minor peak

3 XRD search/match identified ankerite, however, Ca-substituted dolomite also has the same pattern

Note: The quantitative analysis results are normalised to 100% and hence do not include estimates of amorphous

or unidentified phases. Samples 1 through 4 also show evidence of clays but confirmation is not possible without

separating the clay fractions from the bulk samples.

Table A6-2 Major elemental composition of the T2 aquifer core material

SiO2 TiO2 Al2O3 Fe2O3 MnO MgO CaO Na2O K2O P2O5 SO3 Cl Depth (m bgs)

Sample ID (%) (ppm)

163.9 1 5.04 0.01 0.48 1.37 0.01 1.74 46.30 0.00 0.23 0.02 0.19 151

164.6 2 10.82 0.03 0.64 2.04 0.01 1.93 43.09 0.00 0.43 0.02 0.19 156

166.5 4 10.46 0.03 0.69 2.19 0.01 2.56 42.00 0.00 0.45 0.02 0.17 150

166.9 5 6.37 0.01 0.34 1.21 0.00 1.89 46.34 0.00 0.18 0.02 0.14 138

171.0 11 53.54 0.06 1.15 3.45 0.00 0.86 19.58 0.07 0.37 0.03 0.06 97

173.8 14 16.68 0.04 0.56 1.06 0.03 1.08 42.04 0.00 0.17 0.01 0.09 135

176.3 18 45.73 0.08 1.15 2.32 0.01 0.99 24.17 0.11 0.40 0.02 1.20 121

177.9 20 27.15 0.08 1.01 1.87 0.01 1.35 34.16 0.09 0.32 0.02 0.97 142

179.6 22 34.39 0.07 0.94 1.86 0.01 1.07 30.52 0.06 0.30 0.01 0.76 120

182.9 25 18.86 0.04 0.70 1.92 0.02 1.49 38.92 0.01 0.32 0.02 0.14 137

185.7 27 58.92 0.16 1.72 3.38 0.01 1.31 15.92 0.18 0.47 0.02 0.31 130

189.3 29 45.58 0.05 1.15 2.70 0.03 0.68 24.81 0.07 0.38 0.02 0.08 88

Min 5.04 0.01 0.34 1.06 0.00 0.68 15.92 0.00 0.17 0.01 0.06 88

Max 58.92 0.16 1.72 3.45 0.03 2.56 46.34 0.18 0.47 0.03 1.20 156

Mean 27.79 0.05 0.88 2.11 0.01 1.41 33.99 0.05 0.34 0.02 0.36 130


water ASTR project

Page 76

Tab

le A

6-3

Tra

ce e

lem

en

tal co

mp

osit

ion

of

the T

2 a

qu

ifer

co

re m

ate

rial d

ete

rmin

ed

by X

-Ra

y F

luo

res

cen

ce

As

Ba

Br

Ce

Co

C

r C

s

Cu

G

a

I L

a

Mo

N

b

Nd

N

i R

b

Sr

Ta

Th

T

l U

V

Y

Z

n

Zr

Dep

th

(m

bg

s)

Sam

ple

ID

(ppm)

163.9

1

6

21

<1

<20

<5

34

<11

<1

<1

<8

<18

<1

2

<11

<2

16

702

<7

6

4

5

17

2

4

19

164.6

2

13

21

2

<20

5

63

13

11

<1

10

<18

<1

2

<11

<2

20

651

<7

6

4

7

35

3

6

40

166.5

4

10

20

2

21

<5

51

<11

11

<1

<8

<18

<1

3

<11

<2

21

669

7

7

4

4

28

3

4

39

166.9

5

8

18

<1

23

<5

41

15

<1

<1

<8

<18

<1

1

<11

<2

11

542

8

5

4

6

10

2

<2

23

171.0

11

144

28

<1

<20

<5

87

<11

<1

<1

<8

<18

<1

4

<11

5

13

189

<7

7

3

<2

160

4

5

63

173.8

14

18

22

<1

23

<5

51

<11

<1

2

<8

<18

<1

2

<11

<2

9

227

<7

5

5

3

84

3

3

62

176.3

18

142

21

5

21

<5

78

<11

<1

<1

<8

<18

2

4

16

15

13

315

<7

5

3

3

142

6

4

81

177.9

20

86

20

3

<20

<5

72

<11

<1

<1

12

<18

<1

3

<11

<2

12

473

<7

5

5

4

104

5

3

73

179.6

22

60

<13

4

<20

5

119

12

<1

<1

<8

<18

<1

3

<11

5

12

256

8

7

8

<2

119

4

6

57

182.9

25

19

24

<1

<20

7

128

<11

<1

<1

<8

<18

<1

3

<11

<2

15

413

<7

7

8

5

63

3

4

44

185.7

27

52

42

2

<20

<5

101

<11

<1

<1

<8

18

<1

5

<11

11

19

498

<7

7

5

6

189

5

13

109

189.3

29

58

30

<1

<20

<5

104

<11

<1

<1

<8

<18

<1

2

<11

6

12

123

<7

<4

6

3

165

2

7

30

Tab

le A

6-4

Ad

dit

ion

al tr

ace e

lem

en

ts t

hat

we

re b

elo

w t

hat

X-R

ay F

luo

res

cen

ce

dete

cti

on

lim

it

Ag

B

i C

d

Ge

Hf

Hg

P

b

Sb

S

c

Se

Sm

S

n

Te

Yb

D

ep

th (

m b

gs)

Sam

ple

ID

(ppm)

163.9

1

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

164.6

2

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

166.5

4

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

166.9

5

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

171.0

11

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

173.8

14

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

176.3

18

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

177.9

20

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

179.6

22

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

182.9

25

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

185.7

27

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10

189.3

29

<4

<3

<4

<1

<8

<13

<3

<8

<7

<2

<12

<3

<7

<10


water ASTR project

Page 77

Tab

le A

6-5

Ph

ysio

-ch

em

ical c

ha

racte

ris

tics

of

the T

2 a

qu

ife

r co

re m

ate

ria

l

Dep

th (

m

bg

s)

Sam

ple

ID

E

C

Cl

pH

p

H

TC

O

rg

C

TN

N

H4

NO

3

CO

3 a

s

CaC

O3

Exch

an

geab

le c

ati

on

s

CE

C

1:5 soil:water

0.01 M

CaCl 2

KCl extracts

Ca

Mg

N

K

Total

dS/m

mg/kg

(%)

(%)

(%)

mg/kg

mg/kg

(%)

cmol(+)/kg

163.9

1

0.18

24

9.0

7.9

10.9

<0.5

<0.01

<0.5

<0.5

92

1.4

0.87

0.18

0.09

2.5

2.3

164.6

2

0.29

37

8.8

7.9

10.2

<0.5

<0.01

<0.5

<0.5

85

2.3

1.3

0.25

0.18

4.0

2.9

166.5

4

0.20

30

9.0

7.9

10.0

<0.5

<0.01

<0.5

<0.5

86

2.0

1.4

0.23

0.19

3.9

3.6

166.9

5

0.19

14

9.0

7.9

10.8

<0.5

<0.01

<0.5

<0.5

92

1.3

0.70

0.15

0.09

2.3

1.6

171.0

11

0.10

18

9.0

7.9

4.4

<0.5

<0.01

<0.5

<0.5

37

1.2

0.25

0.13

0.20

1.8

1.5

173.8

14

0.09

14

9.3

8.0

8.8

<0.5

<0.01

<0.5

0.5

74

0.88

0.21

0.13

0.03

1.3

0.8

176.3

18

0.77

165

8.4

7.8

5.5

<0.5

<0.01

<0.5

<0.5

46

1.8

0.46

0.08

0.04

2.4

1.3

177.9

20

0.54

79

8.5

7.9

8.0

<0.5

<0.01

<0.5

0.5

63

1.7

0.47

0.10

0.01

2.3

1.3

179.6

22

0.62

104

8.4

7.9

7.2

<0.5

<0.01

<0.5

0.6

58

3.0

0.53

0.07

0.01

3.6

0.9

182.9

25

0.20

24

9.0

8.0

9.3

<0.5

<0.01

<0.5

<0.5

78

1.2

0.63

0.16

0.06

2.1

2.0

185.7

27

0.26

27

8.7

7.9

3.9

<0.5

<0.01

0.6

<0.5

31

1.6

0.52

0.11

0.02

2.2

2.4

189.3

29

0.10

15

9.1

8.0

5.7

<0.5

<0.01

<0.5

0.6

47

1.1

0.16

0.10

0.01

1.3

0.9


Table A6-6 Chemical composition of the source water and groundwater used in the PHREEQC simulations or observed during the ASTR field trial

Analyte PHREEQC simulations ASTR observations Guideline value

(mg/L unless otherwise indicated)

Ambient GW RW2

Source water WE2 Mean

Source water ASR PW2

IW1 RW1 RW1 RW1 NHMRC-NRMMC

2004

Date sampled 22/6/2006 2006-2008

30/4/2007 1/9/2008 2/9/08 2/2/2009 5/3/2009

Temp (°C) 26.9 12.3 18.8 23.0 13.3 13.7 16.2

Electrical conductivity (µS/cm)

3750 231 660 864 413 446 362

pH (-) 7.0 7.1 7.5 7.5 7.0 7.1 8.2 6.5-8.5

Dissolved oxygen 0.03 4.9 0.1 2.9 0.2 0.2

Eh (mV SHE) 193 360 -91 -12 29 206 202

pe=Eh(V)/0.059† 3.3 6.1 -1.5 -0.2 0.5 3.5 3.4

Total dissolved solids (calc from EC)

2020 133 380 460 230 250 203 500

Alkalinity (as CaCO3) 266 69 158 173 185 212 137

Calcium 136 22 44 45 62.5 68.8 46.9

Chloride 913 27 89 138 20 20 32 250

Magnesium 82.9 4.8 13.6 25.5 6.1 6.6 6.3

Potassium 13.2 3.8 6.7 5.1 4.9 5.1 4.6

Sodium 495 18 82 98 15 14 23 180

Sulfate 273 10 47 54.9 3.6 <1.5 11.4 500 (health)

250 (aesthetic)

Bromide 3.27 0.06 0.49 0.11 0.11 0.12

Fluoride 1.2 0.17 0.34 0.65 0.16 0.20 0.21 1.5

Aluminium (t) <0.02 0.17 <0.01 <0.01 0.052 0.033 0.2 (soluble)

Arsenic (t) 0.011 0.001 0.004 0.004 0.002 0.002 0.002 0.007

Arsenic (s) 0.010 0.001 0.004 0.002‡ 0.001 0.002

Barium (t) 0.017 0.013 0.033 0.036 0.7

Cadmium (t) <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 0.002

Chromium (t) <0.003 <0.003 <0.003 <0.003 <0.003 0.005

Chromium (VI) <0.01 <0.003 <0.003 0.05

Copper (t) 0.004 <0.001 <0.001 <0.001 <0.001 2 (health)

1 (aesthetic)

Iron (t) 1.61 0.54 0.36 0.36 5.37 5.85 0.39 0.3

Iron (s) 1.59 0.18 0.36‡ 5.29 5.85

‡ 0.38

Lead (t) <0.0005 0.0006 <0.0005 <0.0005 <0.0005 <0.0005 0.01

Manganese (t) 0.006 0.045 0.004 0.002 0.388 0.355 0.057

Manganese (s) 0.006 0.021 0.002 0.352 0.281

0.5 (health) 0.1 (aesthetic)

Molybdenum (t) 0.001 0.001 <0.0005 <0.0005 0.05

Nickel (t) <0.0005 0.0009 0.0017 <0.0005 0.002 0.002 0.02

Zinc (t) 0.035 0.022 0.01 0.006 0.01 3

Ammonia 0.032 0.020 0.082 0.023 3.4 5.7 0.16 0.5

Nitrate + nitrite (as N) <0.005 0.008 <0.005 <0.005 0.21 <0.005 0.007 50 (NO3-N)

Phosphorus (t) <0.005 0.050 0.028 0.014 0.19 0.24 0.035

Phosphorus (s) 0.007 0.014 0.019 <0.005 0.006 0.006 0.022

Total Organic carbon 1.3 7.0 3.6 2.6 9.5 9.8 4.2

Dissolved Organic carbon

1.2 6.1 2.1 2.6‡ 7.3 6.6 4.2

† @25°C (Appelo and Postma 1999);

‡ adjusted for analytical error (reported soluble>total); bold indicates value

is greater than guideline value


water ASTR project

Page 79

Tab

le A

6-7

Satu

rati

on

in

de

xes

fo

r th

e r

ec

eiv

ing

gro

un

dw

ate

r, t

he p

ote

nti

al s

ou

rce w

ate

rs,

mix

ture

s o

f th

e a

mb

ien

t g

rou

nd

wate

r an

d t

he s

ou

rce w

ate

r an

d

du

rin

g t

he i

nje

cti

on

, sto

rag

e a

nd

reco

ve

ry p

ha

se

s o

f th

e A

ST

R t

rial

A

mb

ien

t G

W

So

urc

e w

ate

r M

ixtu

re o

f am

bie

nt

gro

un

dw

ate

r an

d s

ou

rce

wate

r^

Inje

cti

on

S

tora

ge

Reco

very

RW2

WE2

Mean

ASR PW2

1:1 Amb

& W

E2

1:1 Amb

& ASR

PW2

0.12:0.88

Amb &

WE2

0.12:0.88

Amb & W

E2

IW1

P1 (166-

169 m

bgs)

P2 (211-

215 m

bgs)

P3 (166-

169 m

bgs)

RW1

RW1

Date

sampled

22/6/2006

2006-

2008

30/4/2007

Mix at

equilibrium

with

carbonate

minerals

1/9/08

16/10/08

16/10/08

16/10/08

2/2/09

5/3/09

Calcite

-0.04

-1.21

-0.17

-0.41

-0.14

-0.91

0.00

-0.08

0.61

-0.03

0.41

-0.23

0.52

Dolomite

0.05

-2.91

-0.10

-0.82

-0.14

-2.04

0.00

0.07

1.17

0.13

0.54

-1.30

0.42

Siderite

0.20

-1.09

-0.08

-0.09

0.07

-0.44

0.00

0.00

0.38

0.76

0.08

0.83

0.54

Al(OH) 3 (a)

-1.68

0.00

-2.18

-0.52

-1.81

-0.13

-0.91

-2.32

-3.04

-0.60

-2.73

-0.79

Al data not

availa

ble

Fe(O

H) 3 (a)

0.33

2.94

0.87

-1.96

-1.68

-2.02

-0.04

-0.08

0.31

-0.26

0.36

0.33

0.40

Goethite

6.23

8.37

6.53

3.70

4.10

3.46

5.44

5.74

5.92

5.64

5.95

5.80

5.97

Hematite

14.46

18.68

15.04

9.39

10.20

8.88

12.84

13.47

13.81

13.29

13.88

13.55

13.90

^ mixtures examined at pe=0


Has As been

confirmed in the

storage zone?

Does reliable existing

data or baseline

monitoring indicate

As>1 µg/L* in ambient

g/water?

No arsenic

release

expected

no

Is As present with

oxidised

(ie Fe oxides) or

reduced (ie pyrite)

minerals?

yes

Will source

water lower the

pH of the

storage zone?

Does source water

contain OC?no

Does source water

contain O2, NO3-or

other oxidising

agents?

No pyrite

oxidation

expectedno

Pyrite

oxidation and

arsenic

release may

be slow

Is aquifer or injectant

temperature >10°C?

yes

no

Pyrite oxidation

expected

Arsenic

release

expected

Dissolution of

Fe(III)oxide

expected

No arsenic

release

expected

No reductive

dissolution of

Fe(III)oxide

expected

yes

WE02 mean TOC 7.0 mg/L

>amb GW TOC 1.4 mg/L

yes

no

yes

Do you have data on

the aquifer

mineralogy or

elemental

composition?

yes

Does the aquifer

contain aerobic

(oxidised) or

anaerobic (reduced)

minerals?

Is As in

recovered water

from nearby MAR

operations

>7 µg/L?

nono

no

yesyes

As 6-144 ppm*

oxidised^

goethite

0.6-2.2%

hematite

0.2-0.7%

reduced or anaerobic

Figure A6-1 Decision tree used to identify potential for arsenic release from the aquifer sediments (EPHC-NHMRC-NRMMC 2008a)

*As quantified using XRF, acid-digestible concentration to be determined, ^Fe present in sediments in oxidised and reduced

forms, but oxidised forms detected more frequently within core samples


Will water with

soluble Fe mix

with aerobic

water?

No Fe release

expected

No Fe(III)

clogging

expected

Will source water

lower the pH of the

storage zone?

no

no

yes

Does source water

contain O2, NO3-or

other oxidising

agents?

Does source water

contain OC ? No Fe release

expectedno

no

No reductive

dissolution of

Fe(III)oxide

expected

Pyrite

oxidation and

Fe release

may be slow

Is aquifer or

injectant

temperature

>10°C?

Dissolution of

Fe(III)oxide and

Fe(II) release

expected

no

yes

WE02 mean TOC 7.0 mg/L

>amb GW TOC 1.4 mg/L yes

no

yes

No Fe release

expected

Pyrite oxidation,

Fe(III) oxy/

hydroxide

precipitate

yes

yes

Increased Fe in

recovered water

expected

Fe(III) clogging

expected

Has Fe been

confirmed in the

storage zone?

Does reliable existing

data or baseline

monitoring indicate

Fe>0.1 mg/L in

ambient g/water?

no

Do you have data on

the aquifer

mineralogy or

elemental

composition?

yes

Is Fe in

recovered water

from nearby MAR

operations

>0.3 mg/L?

no

no

Is Fe present with

oxidised

(ie oxides) or reduced

(ie sulfide) minerals?

yes

Does the aquifer

contain aerobic

(oxidised) or

anaerobic (reduced)

minerals?

yes

oxidised^

goethite

0.6-2.2%

hematite

0.2-0.7%

reduced or anaerobic

Fe(III)

clogging

expected

Figure A6-2 Decision tree used to identify the potential for iron release from the aquifer sediments (EPHC-NHMRC-NRMMC 2008a)

^Fe present in sediments in oxidised and reduced forms, but oxidised forms detected more frequently within core samples


APPENDIX 7 ENTRY LEVEL ASSESSMENT FOR ASTR

The following tables show the completed entry-level risk assessment for the ASTR scheme, as per section 4.3 of the draft MAR guidelines (EPHC–NHMRC–NRMMC 2008a).

Table A7-1 Entry-level risk assessment — Part 1: viability

Attribute Answer

1 Intended water use

• Is there is an ongoing local demand or clearly defined environmental benefit for recovered water that is compatible with local water management plans?

� Recovered water intended for use as drinking water supplies

� continue viability assessment

2 Source water availability and right of access

• Is adequate source water available, and is harvesting this volume compatible with catchment water management plans?

� Adequate volume of stormwater available, harvesting is compatible with catchment management plans (i.e. reducing volume of stormwater discharged to sea).


3 Hydrogeological assessment

• Is there at least one aquifer at the proposed managed aquifer recharge site capable of storing additional water?

� T2 aquifer capable of storing additional water


• Is the project compatible with groundwater management plans?

� project is compatible with groundwater management plans


4 Space for water capture and treatment

• Is there sufficient land available for capture and treatment of the water?

� Stormwater capture and treatment reedbed already in existence at Parafield Airport


5 Capability to design, construct and operate

• Is there a capability to design, construct and operate a managed aquifer recharge project?

� Capability exists between project partners to design, construct and operate project

� Go to Part 2


Table A7-2 Entry-level risk assessment — Part 2: degree of difficulty

Issue Question Possible answers ASTR answers Difficulty 1 Source water quality with respect to groundwater environmental values

Does source water

quality meet the

requirements for the

environmental values

of ambient

groundwater?

If Yes — low risk of pollution is

expected.

If No — high maximal risk is likely.

Expect Stage 2 investigations to

assess preventive measures to

reduce risk of groundwater

contamination beyond attenuation

zone (and size of attenuation

zone).

Yes – environmental

value of ambient

groundwater is low. Too

saline to be used for

irrigation. No significant

GDEs.

Low

2 Source water quality with respect to recovered water end use environmental values

Does source water

quality meet the



of intended end uses

of water on recovery?

If Yes — low risk of pollution of

recovered water is expected.

However, this is not a sufficient

condition for low risk due to

aquifer reactions.

If No — high maximal risk is likely.

Expect Stage 2 investigations to

assess this risk.

No – stormwater does

not meet drinking water

standards.

Require Stage 2

investigations to assess

this risk.

High

3 Source water quality with respect to clogging

Is source water of low

quality, for example:

total suspended

solids >10 mg/L,

total organic carbon

>10 mg/L,

total nitrogen

>10 mg/L?

And is soil or aquifer

free of macropores?

If Yes — high risk of clogging of

infiltration facilities or recharge

wells. Pre-treatment will need

consideration regardless of

answers to Q1 and Q2.

If No — lower risk of clogging is

expected. However, this is not a

sufficient condition for low risk,

due to dependence of clogging on

aquifer characteristics that would

be revealed by stage 2

investigations.

Yes – source water is of

moderate quality, and

should lead to a low-

moderate rate of

clogging in the target

limestone aquifer.

Require Stage 2


this risk.

Moderate

4 Groundwater quality with respect to recovered water end use environmental values

Does ambient

groundwater meet

the water quality



of intended end uses

of water on recovery?

If Yes — low risk of inadequate

recovery efficiency is expected.

If No — some risk of inadequate

recovery efficiency is expected.

No – ambient

groundwater salinity

above drinking water

standards.

Require Stage 2


this risk.

High

5 Groundwater and drinking water quality

Is either drinking

water supply, or

protection of aquatic

ecosystems with high

conservation or

ecological values, an

environmental value

of the target aquifer?

If Yes — high risk of groundwater

pollution if recharged by water if

answer to Q2 is No.

If No — low risk of groundwater

pollution is expected.

No – target aquifer is too

saline for use as

drinking water supply;

target aquifer does not

support aquatic

ecosystems with high

conservation value.

Low


Issue Question Possible answers ASTR answers Difficulty 6 Groundwater salinity and recovery efficiency

Does the salinity of

native groundwater

exceed:

(a) 10000 mg/L, or

(b) the salinity

criterion for uses of

recovered water?

If Yes to both — high risk of

achieving only low recovery

efficiency. Aquifer hydraulic

characteristics, especially layering

within the aquifer will need careful

examination in Stage 2.

If Yes to only (b) — moderate risk

of low recovery efficiency is

expected.

If No to both — low risk of low

recovery efficiency.

Yes to (b) only –

ambient groundwater

salinity above drinking

water standards.

Water harvesting facility

already exists.

Horizontal drilling

beneath railway line and

well construction on

council reserve require a

permit.

Moderate

7 Reactions between source water and aquifer

Is redox status, pH,

temperature, nutrient

status and ionic

strength of

groundwater similar

to that of source

water?

If Yes — low risk of adverse

reactions between source water

and aquifer is expected.

If No — high risk of adverse

reactions between source water

and the aquifer is possible, and

will warrant geochemical

modelling in Stage 2.

No – redox status,

nutrient status, and ionic

strength of source water

is different to that of

groundwater.

Require Stage 2


this risk.

High

8 Proximity of nearest existing groundwater users , connected ecosystems and property boundaries

Are there other

groundwater users,

groundwater–

connected

ecosystems or a

property boundary

near (within 100–

1000 m) the MAR

site?

If Yes — high risk of impacts on

users or ecosystems is possible,

and this will warrant attention in

Stage 2.

If No — low risk of impacts on

users or ecosystems is likely.

Yes – property

boundaries within 100 m

of MAR site (but target

aquifer unusable for

irrigation or drinking).

ASR site nearby.

Require Stage 2


this risk.

Moderate

9 Aquifer capacity and groundwater levels

Is the aquifer

confined and not

artesian? or is it

unconfined, with a

watertable deeper

than 4 m in rural

areas or 8 m in urban

areas?

If Yes — low risk of water logging

or excessive groundwater mound

height is expected.

If No — high risk of water logging

or excessive groundwater mound

height is expected..

Yes – target aquifer

confined and not

artesian. However,

injection may cause

aquifer to become

artesian.

Require Stage 2


this risk.

Moderate

10 Protection of water quality in unconfined aquifers

Is the aquifer

unconfined, with an

intended use of

recovered water that

includes drinking

water supplies?

If Yes — high risk of groundwater

contamination from land and

waste management.

If No — lower risk of groundwater

contamination from land and

waste management.

No – target aquifer is

confined.

Low


Issue Question Possible answers ASTR answers Difficulty 11 Fractured rock, karstic or reactive aquifers

Is the aquifer

composed of

fractured rock or

karstic media, or

known to contain

reactive minerals?

If Yes — high risk of migration of

recharge water is expected. There

is a need for an enlarged

attenuation zone, beyond which

pre-existing environmental values

of the aquifer are to be met.

Dissolution of aquifer matrix and

potential for mobilisation of metals

warrant investigation in Stage 2.

If No — low risk of the above is

expected.

Yes – target aquifer

contains reactive

minerals, and

dissolution of carbonate

minerals is possible.

Require Stage 2


this risk.

Moderate

12 Similarity to successful projects

Has another project

in the same aquifer

with similar source

water been operating

successfully for at

least 12 months?

If Yes — take validation and

verification data from the existing

project(s) into account when

designing the current project and

the Stage 2 investigations and

subsequent risk assessments.

If No — expect that all

uncertainties will need to be

addressed in the Stage 2

investigations.

Yes – Parafield ASR

scheme has been

operating successfully in

the same aquifer for 6

years.

Low

13 Management capability

Does the proponent

have experience with

operating MAR sites

with the same or

higher degree of

difficulty, or with

water treatment or

water supply

operations involving a

structured approach

to water quality risk

management?

If Yes — low risk of water quality

failure due to operator

experience.

If No — high risk of water quality

failure due to operator

inexperience. The proponent is

recommended to gain instruction

in operating such systems (e.g. a

MAR operator’s course or aquifer

storage and recovery course) or

engage a suitable manager

committed to effective risk

management in parallel with

Stage 2, to reduce pre-

commissioning residual risks to

low.

Yes – proponents have

experience with similar

MAR operations.

Low


Issue Question Possible answers ASTR answers Difficulty 14 Planning and related requirements

Does the proposed

project require

development

approval; is it in a

built up area; built on

public, flood-prone or

steep land; close to a

property boundary;

contain open water

storages or

engineering

structures; likely to

cause public health

or safety issues,

nuisance from noise,

dust, odour or

insects, or adverse

environmental

impacts?

If Yes – Development approval

process will require that each

potential issue is assessed and

managed. This may require

additional information and steps in

design.

If No – Process for development

approval, if required, is likely to be

considerably simpler.

Yes – project requires

development approval.

Require Stage 2

investigations to provide

additional information.

Moderate

Table A7-3 Summary of degree of difficulty

Degree of

difficulty

Issue Investigations required at stage

two

High

2. Source water quality with respect to

recovered water end use

environmental value

Source water quality and hazard

attenuation processes

4. Groundwater quality with respect to

recovered water end use


Groundwater entrainment

evaluation (modelling)

7. Reactions between source water

and aquifer

Geochemical evaluation

Moderate

3. Source water quality with respect to

clogging.

Clogging evaluation

6. Groundwater salinity As per 4.

8. Proximity of nearest existing

groundwater users, connected

ecosystems and property

boundaries

Interactions with nearby ASR site

warrant consideration

9. Aquifer capacity and groundwater

levels.

Extent of artesian zone to be

identified

11. Fractured rock, karstic or reactive

aquifers

Geochemical evaluation of the

dissolution of calcite

14. Planning and related requirements As required by council approval

processes


APPENDIX 8 ASTR RISK MANAGEMENT PLAN

This section contains a gap analysis of the requirements of a risk-based management plan consistent with the example given in Table A1.1 of the Australian Guidelines for Water Recycling (NRMMC-EPHC-AMHC 2006). This Appendix lists the 12 elements of the framework for management of recycled water quality and use, and shows how the ASTR scheme could potentially meet the various elements. This is intended to initiate discussion on the actions that need to be undertaken without prescribing roles for each organisation.

A.1 Commitment to responsible use and management of recycled water quality (Element 1) Responsible use of recycled water, partnerships and engagement of stakeholders (including the public) The development of the ASTR scheme has been possible through the involvement of different parties, with expertise in different fields, and that are represented in the risk management committee:

� Scientific and Industrial Research Organisation Scientific and Industrial Research Organisation Land and Water (CSIRO)

� Salisbury City Council (CoS) � United Water International (UWI) � SA Environmental Protection Agency (EPA) � SA Department of Health (SA DH) � SA Water (SAW) � Department of Water, Land and biodiversity conservation (DWLBC)

Other relevant stakeholders identified in the ASTR scheme are: � Adelaide Mount Lofty Ranges Natural Resource Management Board � Delfin Lend Lease � Community groups / industry groups / general public / end users of the recycled

water The partners involved have the expertise necessary to develop and support the scheme. Areas of expertise required include:

� Catchment and stormwater management � Potable water risk management � Reedbed treatment, ASTR treatment, disinfection and other forms of water

treatment � Microbiological, physical and chemical water quality, water quality monitoring � Water supply system operation e.g. security, storage operation, mains flushing � Constructor/contractor management � Technical writing e.g. policy, specifications, standard operating procedures � Quality management systems

Actions:

• Form a stakeholder reference group for consultation and communication with project stakeholders and meet annually or as required.

• Form an expert reference group to further refine the risk assessment and management of the ASTR system using the principals of the Australian Guidelines for Water Recycling 2A Augmentation of Drinking Water Supplies and 2C Managed Aquifer Recharge and meet annually or as required.

• Develop public engagement program


Regulatory and formal requirements

• Managed Aquifer Recharge projects in South Australia require the approval of the DWLBC to construct a bore and extract water from an aquifer, and the EPA to inject into an aquifer. The extraction of water also requires the approval of the SA DH. DWLBC is a member of the ASTR project management committee, and EPA and SA DH are involved in the ASTR risk management committee. Because of the novelty of the ASTR project, with no similar projects in Australia, participation of these agencies is essential.

• CoS is responsible for the ASTR scheme, from the stormwater catchment to the recovery at the wells. SAW is responsible for the delivery of the water to Mawson Lakes through a non-potable water supply system (3rd pipe system), and UWI is contracted by SAW to perform this task. All the other agencies/partners involved give support to the project in terms of advice on operation of the system, monitoring, and protection of the environment and human health.

• Regular meetings ensure that the different stages of the project are achieved. Any changes to the ASTR scheme are discussed and reviewed during these meetings.

• The minutes of the meetings detail the actions to be taken by the different partners and how to inform and engage the stakeholders. The minutes are accepted by all of the partners and become a document of reference for the project.

Actions:

• Ensure that responsibilities are understood and communicated to designers, installers, maintainers, operations employees, contractors and end users. A document including a list of all tasks/work to be done in the project and people responsible for them, as well as their contact details and a backup person is recommended. This needs to be documented in a comprehensive risk management plan.

Recycled water policy Actions:

• Project Manager responsible to the risk management plan to obtain sign off by senior managers.

• Develop a recycled water quality policy, endorsed by the CEO, to be implemented by CoS. This policy could be similar to the one adopted by UWI, which has as its main objective to boost the water recycling and reuse, with MAR being one of the selected technologies to achieve it. This policy must be visible, communicated, understood and implemented by employees and contractors.

A.2 Assessment of the recycled water system (Element 2) Source of recycled water, intended uses, receiving environments and routes of exposure

• The source of the recycled water is urban stormwater.

• The intended water use is for urban landscape irrigation and supply to the third pipe system at Mawson Lakes.

• The principal route of exposure for the completed ASTR scheme will be irrigation. Considering the additional uses that the recovered water at Mawson Lakes, other possible routes of exposure includes cross connections to the drinking water supply and contact with swimming pools filled with the ASTR water.

• Receiving environments include the groundwater, surface water, plants, soils and the marine environment.


Actions:

• To consider inadvertent or unauthorised uses as part of the risk management plan. This is especially important right now, as the water is being recovered and tested from drinking water quality as part of the ASTR project, and its appropriateness for drinking water supply cannot be assured. The use of this water for irrigation of parks or for artificial waterways may not pose a risk for the population but needs to be quantitatively evaluated. If potential unintentional uses are practised (by tapping into the recycling pipeline) the population might be at risk. It is recommended to have routine inspections of the pipelines and certification on their installation.

Recycled water system analysis

• Information on the Parafield stormwater harvesting system and the ASTR project have been previously assembled in reports prepared by CSIRO (Swierc et al. 2005, Page et al. 2008) and in the present report. CSIRO has wide expertise in MAR schemes and recycled water systems.

• A flow diagram of the ASTR scheme appears in Swierc et al. (2005) but is out of date. Actions:

• The flow diagram must be updated to reflect changes as part of the risk management plan.

Assessment of water quality data

• Data collected as part of the ASTR project has been compiled in earlier sections of this report, including assessment of the previous SCADA system data used for operational monitoring.

Actions:

• Continue to develop and expand the data set as part of the revision of the risk management plan. This data forms the basis of future risk assessment revisions.

• Develop assessment criteria for the SCADA data and appropriate reporting functions to meet the reporting and communication requirements as well as operational monitoring of CCPs.

Hazard identification and risk assessment

• In the present report, the Australian Guidelines for Water Recycling 2A: Augmentation of Drinking Water Supplies and 2C Managed Aquifer Recharge have been applied to identify the hazards to human health and the environment. Hazards were broadly classified in 12 groups and were identified in the different phases of the risk assessment: � Phase 1 of the risk assessment (preliminary screening, see Swierc et al. 2005)

identified most of the possible hazards in the system. In the preliminary quantitative risk assessment performed by Page et al. (2008), the list of the hazards was narrowed, and the main human health hazards identified were pathogens, organic chemicals, inorganic chemicals (arsenic and iron), turbidity and salinity.

� Phase 2 (maximal risk assessment), which is gathered in the present report, confirms all the hazards identified in the preliminary risk assessment by Page et al. 2008, and a more exhaustive evaluation of environmental hazards has been performed.

• Hazards to human health: � Stormwater can contain pathogenic bacteria, viruses and protozoa. An update of

the preliminary QMRA (Page et al. 2008) appears in the present report and includes post-recovery treatment. While currently assessed as of acceptable risk; verification monitoring still needs to be performed.


� A large set of organic chemical hazards have been evaluated and potentially herbicides such as simazine while currently assessed as of an acceptable risk there is high uncertainty in the estimate.

� Arsenic and Iron may potentially be released from the aquifer, while currently assessed as of an acceptable risk additional verification monitoring is required.

� Aesthetic problems, regarding turbidity and colour (resulting from suspended sediments and iron), must be also considered.

� Salinity can pose a risk, as the native groundwater is brackish. Hydrogeological models predict that at the end of the flushing period the recovered water will have the salinity suitable for a potable water supply but this remains to be verified on a continuous basis.

• Aquifer sustainability: � Some of the hazards considered that could have an impact in an aquifer are: high

pressures and flows, aquifer stability and dissolution, pollution of the aquifer, decrease of groundwater levels, harm to groundwater dependent ecosystems and an increase in electricity consumption and greenhouse gases production. However, none of these hazards are actual risks for the aquifer as far as it has been operated till now.

Actions:

• Continue to assess the risk for each hazard and hazardous event and document in revisions of the risk management plan.

A.3 Preventive measures for recycled water management (Element 3) Preventive measures and multiple barriers

• Barriers in place include: � Bunds around and covers over industrial chemical stores � Holding storage and in-stream basin: settling of gross particles � Cleansing reedbed: settling of particles, nutrients reduction, pathogens decay and

degradation/adsorption of chemical compounds. � Subsurface treatment: pathogens decay, organic compounds degradation, settling

of particles

• When the water doesn’t meet the quality requirements for injection it can be diverted.

• Supporting programs are in place to avoid pollution of the stormwater and ensure good performance of the catchment and treatment area: � Street sweeping programs in the urban catchment � Stormwater pollution prevention program - Be Stormwater Smart � SA EPA industry licensing program and codes of practice � Pesticide application programs in the Parafield Gardens stormwater catchment � ASTR site security � Sewer leak detection program � Equipment maintenance

Actions:

• Identify alternative or additional preventive measures that are required to ensure risks are reduced to acceptable levels.

• Document the preventive measures and strategies, addressing each significant risk as part of the evolution of the risk management plan.

Critical control points

• Critical Control Points (CCPs): the effluent of the in-stream basin, the effluent of the cleansing reedbed and the recovered water.


• Quality Control Points (QCPs): the water entering the in-stream basin (stormwater gathered from different catchments), the effluent of the holding storage and the injected water.

• Initial proposed critical limits (Swierc et al. 2005) were postulated: � effluent of the in-stream basin: turbidity < 100 NTU � effluent of the holding storage: turbidity < 10 NTU � injected water quality: turbidity < 5 NTU, TDS < 100 mg/L and pH 6.5-9.5 � recovered water: turbidity < 5 NTU, TDS < 100 mg/L and pH 6.5-9.5.

• The SCADA system is the main tool for operational control, as data is received online and responses can be quick.

• Regular inspections, monitoring of the water quality and training of the operators have been identified as important preventive measures, e.g. a preventive measure in place is a net covering the Parafield Stormwater Harvesting System basins to prevent birds congregating in the area.

Actions:

• Barriers need to be validated.

• CCP and QCP limits and trigger values need to be assessed, linked to appropriate operational procedures and recorded as part of the risk management plan.

A.4 Operational procedures and process control (Element 4) Operational procedures Actions:

• Document all procedures and compile them into the risk management plan.

• Procedures need to include: � preventive measures and their purpose in reducing risk � operational procedures for relevant activities � operational monitoring protocols, including parameters and criteria: who, how, and

when are the samples taken, which parameters, volumes necessary, frequency, etc

� schedules and timelines for communication, reporting and inspection � operational corrective actions for when CCP limits are exceeded � reactive materials used: dosage, frequency, quality of the reactive materials, who

supplies them, etc… � data and records management requirements for the risk management plan and

storage of data � maintenance procedures � rapid communication systems to deal with problems � calibration and verification of the instrumentation/equipment � responsibilities and authorities � water recycling training

Operational monitoring

• Operational monitoring is performed with probes placed in the CCPs of the system. These probes monitor flux, volumes, pressures, pH, TDS, temperature and turbidity. The data is managed through the SCADA system.

Actions:

• Document monitoring protocols into an operational monitoring plan.

• Define the frequency of the routine analysis of the results as part of the risk management plan.


Operational corrections

• Corrective actions in place include: � Diversion of the stormwater if turbidity is > 100 NTU (to be evaluated) � Stop pumping when water levels are low � Over/under pressure: stop pumping � Injection water not meeting quality criteria: stop injection, and diversion of the

water to other uses � Turbidity higher than the limit: reject the water for consumption, divert it to other

uses (irrigation, artificial waterways, flushing, fire control, etc) Actions:

• Document the procedures for corrective action where operational parameters are not met as part of the risk management plan.

• Establish rapid communication systems to deal with unexpected events.

Equipment capability and maintenance

• The on-line water quality probes are calibrated every three months. Actions:

• Ensure that the equipment performs adequately and provides sufficient flexibility and process control.

• Establish a program for regular inspection and maintenance of all equipment, including monitoring equipment.

• A more frequent maintenance regime is recommended (Page et al. 2008). Materials and chemicals

• Materials used along the system were selected in order to avoid introducing contaminants in the water recycling scheme

Actions:

• Quality assurance for materials and chemicals must be applied, in order to avoid introducing contaminants in the water recycling scheme.

• Establish documented procedures for evaluating chemicals, materials and suppliers.

A.5 Verification of recycled water quality and environmental performance (Element 5) Recycled water quality monitoring, application site and receiving environment monitoring

• Recommended parameters to be monitored include (Appendix E); � Basic parameters (to verify the online monitoring by probes) � Microbiological parameters � Inorganic chemicals � Organic chemicals � Nutrients � Salinity related parameters

• Monitored points are the same as identified as CCPs and QCPs

• Frequency of monitoring is variable and depends on: � the parameters; e.g., selected pathogens and organic chemicals are monitored in

specific campaigns by passive samplers, whereas indicators (E. coli) and nutrients are monitored in a monthly or bimonthly basis


� the stage of the process: e.g. during storage phase, some samplings are performed to track changes in the quality of the water, but during the recovery phase more frequent analyses must be performed to ensure that the water produced meets the quality criteria set in the ADWG.

Actions:

• Compile the water quality monitoring plan as part of the risk management plan ensuring operational and reporting requirements are met.

Documentation and reliability

• A risk management framework and gap analysis has been established by CSIRO to research the quality of the water along the treatment system and will form the basis of future monitoring of the ASTR scheme (Appendix E)

Actions:

• Document the sampling plan as part of the risk management plan established for each characteristic, including the location and frequency of sampling, ensuring that monitoring data is representative and reliable.

Satisfaction of users of recycled water Actions:

• Establish an inquiry and response program for users of recycled water (Mawson Lakes), including appropriate training of people responsible for the program.

Short-term evaluation of results

• Reports of the results are sent to the HC and the EPA as part of the formal reporting requirements.

Actions:

• Establish procedures for the short-term review of monitoring data in quarterly.

• Develop reporting mechanisms internally and externally, where required. � Internal mechanisms of reporting should be developed, including meetings to

discuss the results obtained. � Internal reports should be written every 3 months, and should include a summary

of all the results during the selected period. � Any incidences or results out of specifications must be highlighted in the internal

reports. � The corrective measures undertaken must be also reported. � This information, especially the problems/incidences arisen, is the basis to define

preventive measures, which also form part of the reporting and revision of the risk management plan.

� The quality of the produced water and any change in the system must be communicated appropriately to the stakeholders.

Corrective responses Actions:

• Establish and document procedures for corrective responses to non conformance or feedback from users of recycled water.

• Establish rapid communication systems to deal with unexpected events. � The communication system should involve a warning alert from the SCADA

system, which is tracked by the person in charge.


• Communication systems and corrective actions must be reviewed as part of the revision of the risk management plan.

A.6 Management of incidents and emergencies (Element 6) Communication

• A first communication exercise was performed, and water was recovered from an adjacent ASR well, bottled and named “Recharge”. The water was bottled for the Prime Minister’s Science, Engineering and Innovation Council meeting June 2007 (PMSEIC 2007)

• A new communication exercise will report results on the completion of the DIISR-supported component of the ASTR project, April 2009.

Actions:

• Define communication protocols with the involvement of relevant agencies and prepare a contact list of key people, agencies and stakeholders in the risk management plan.

• Develop a public and media communications strategy.

Incident and emergency response protocols Actions:

• Define potential incidents and emergencies and document procedures and response plans with the involvement of relevant agencies in the risk management plan.

• Train employees and regularly test emergency response plans.

• Investigate any incidents or emergencies and revise protocols as necessary.

A.7 Operator, contractor and end user awareness and training (Element 7) Actions:

• Develop mechanisms and communication procedures to increase operator, contractor and end user awareness of, and participation in, recycled water quality management and environmental protection.

• Ensure that operators, contractors and end users maintain the appropriate experience and qualifications.

• Identify training needs and ensure resources are available to support training programs.

• Document training and maintain records of all training sessions.

A.8 Community involvement and awareness (Element 8) Consultation with users of recycled water and the community Actions:

• Assess requirements for effective involvement of users of recycled water and the community.

• Develop a comprehensive strategy for consultation.

Communication and education Actions:

• Develop a comprehensive communication and education strategy.


A.9 Validation, research and development (Element 9) Validation of processes and equipment

• Validation efforts in ASTR have been directed to the surface and subsurface treatment performance. Examples of the validation processes are the deployment of passive samplers to test the presence of organic chemicals and the pathogen decay chamber studies. Specifically for the aquifer treatment, it has been validated: � the water residence time � the attenuation of pathogens and organic chemicals in the subsurface � mobilisation of metals during passage between injection and recovery wells.

Actions:

• Validation of SCADA system, CCPs and QCPs are effective in reducing the risks.

Investigation studies and research monitoring

• Develop a research plan as part of the risk assessment plan, to address remaining critical information needs.

A.10 Documentation and reporting (Element 10) Management of documentation and records Actions:

• Document information pertinent to all aspects of recycled water quality management, and develop a document-control system to ensure current versions are in use. � register of relevant regulatory requirements � names and contact details of stakeholders � a process diagram of the entire system � operational procedures and process controls � critical control points, quality control points and associated critical limits � incidence response procedures � training programs and records for employees and contractors � monitoring information (baseline, operational, validation and verification data) � communications to authorities concerning system performance and monitoring

results.

• Establish a records-management system and ensure that employees are trained to complete records.

• Periodically review documentation and revise as necessary.

Reporting Actions:

• Establish procedures for effective internal and external reporting.

• Produce an annual report aimed at users of recycled water, regulatory authorities and stakeholders.

A.11 Evaluation and audit (Element 11) Long-term evaluation of results

• Information on the ASTR system is contained in various reports.


Actions:

• Centralise all information on the ASTR system for future reference

• Long term evaluation of the results should be discussed in the internal meetings, in a regular basis (e.g. yearly), and reviewed after 3-5 years performance to detect tendencies.

• Results must be documented and reported as part of the revision of the risk management plan.

Audit of recycled water quality management Actions:

• Establish processes for internal and external audits.

• Document and communicate audit results.

A.12 Review and continuous improvement (Element 12) Review by senior managers Actions:

• Senior managers review the effectiveness of the management system and evaluate the need for change to the risk management plan.

Recycled water quality management improvement plan Actions:

• Develop a recycled water quality management improvement plan.

• Ensure that the plan is communicated and implemented, and that improvements are monitored for effectiveness.

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