corrective action implementation & verification report · pdf filediageo ireland —...

- Corrective Action Implementation & Verification Report (AEC6)

Great Northern Brewery (IPPC Register No. P0440) 19 June 2014 FINAL 47092707

Prepared for: Diageo Ireland

IRELAND

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Diageo Ireland — Corrective Action Implementation & Verification Report (AEC6)

CORRECTIVE ACTION IMPLEMENTATION & VERIFICATION GREAT NORTHERN BREWERY IPPC Licence Register No. P0440

June 2014 47092707 Issue 2

ii

DOCUMENT PRODUCTION / APPROVAL RECORD

Issue No: 2 Name Signature Date Position

Prepared by Sinead Fitzpatrick

19 June 2014 Principal Environmental Scientist

Checked & Approved by

Kevin Forde

19 June 2014 Principal Environmental Hydrogeologist

URS Ireland Limited 410-411 Q House 76 Furze Road Sandyford Dublin 18 Ireland Tel: +353 (0) 1 293 3200 Fax: +353 (0) 1 293 3201

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June 2014 47092707 Issue 2

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Limitations

URS Ireland Limited (“URS”) has prepared for the sole use of Diageo Ireland (“the Client”) in accordance with the Agreement under which our services were performed (Proposal dated 7 April 2014). No other warranty, expressed or implied, is made as to the professional advice included in this Report or any other services provided by URS. This Report is confidential and may not be disclosed by the Client nor relied upon by any other party without the prior and express written agreement of URS.

The conclusions and recommendations contained in this Report are based upon information provided by others and upon the assumption that all relevant information has been provided by those parties from whom it has been requested and that such information is accurate. Information obtained by URS has not been independently verified by URS, unless otherwise stated in the Report.

The methodology adopted and the sources of information used by URS in providing its services are outlined in this Report. The work described in this Report was undertaken between April and June, 2014 and is based on the conditions encountered and the information available during the said period of time. The scope of this Report and the services are accordingly factually limited by these circumstances.

Where assessments of works or costs identified in this Report are made, such assessments are based upon the information available at the time and where appropriate are subject to further investigations or information which may become available.

URS disclaim any undertaking or obligation to advise any person of any change in any matter affecting the Report, which may come or be brought to URS’ attention after the date of the Report.

Certain statements made in the Report that are not historical facts may constitute estimates, projections or other forward-looking statements and even though they are based on reasonable assumptions as of the date of the Report, such forward-looking statements by their nature involve risks and uncertainties that could cause actual results to differ materially from the results predicted. URS specifically does not guarantee or warrant any estimate or projections contained in this Report.

Unless otherwise stated in this Report, the assessments made assume that the sites and facilities will continue to be used for their current purpose without significant changes.

Where field investigations are carried out, these have been restricted to a level of detail required to meet the stated objectives of the services. The results of any measurements taken may vary spatially or with time and further confirmatory measurements should be made after any significant delay in issuing this Report.

Copyright

© This Report is the copyright of URS Ireland Limited. Any unauthorised reproduction or usage by any person other than the addressee is strictly prohibited.

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June 2014 47092707 Issue 2

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TABLE OF CONTENTS 1. INTRODUCTION ............................................................... 2

1. BACKGROUND FROM STAGE 1 AND 2 ......................... 2

1.1 Stage 1 - Preliminary Site Assessment (PSA) .............. 2

1.2 Stage 1 - Detailed Site Assessment (DSA) .................... 2

1.3 Stage 1 - Detailed Quantitative Risk Assessment (DQRA) .............................................................................. 3

1.4 Stage 2 - Remedial Options Assessment (ROA) .......... 4

1.5 Stage 2 - Corrective Action Design and Implementation Plan (AEC6) and Enabling Works ................................... 4

1.6 Stage 3 - Enabling Works ................................................ 4

2. OBJECTIVE ....................................................................... 4

3. OUTLINE SCOPE OF WORKS ......................................... 5

4. DETAILED SCOPE OF WORKS ...................................... 8

4.1 Remediation Personnel ................................................... 8

4.2 Health and Safety Considerations ................................. 9

4.3 Remedial Technology and Design ................................. 9

4.4 Environmental Monitoring Programme and Results .. 17

4.5 Soil and Groundwater Waste Management ................. 18

5. SYSTEM PERFORMANCE ............................................. 21

6. MONITORING RESULTS ................................................ 22

7. LIAISON WITH THE REGULATOR AND THIRD PARTIES ......................................................................................... 22

8. VERIFICATION ................................................................ 23

9. REINSTATEMENT .......................................................... 25

10. AFTERCARE PLANNING ............................................... 25

11. CONCLUSIONS & RECOMMENDATIONS .................... 25

FIGURS

TABLES

APPENDIX A – PHOTOGRAPHIC RECORD

APPENDIX B – TRAIL PIT LOGS

APPENDIX C – WASTE CLASSIFICATION:HAZWASTEONLINETM

OUTPUTS

APPENDIX D – LABORATORY RESULTS

APPENDIX E – WASTE DISPOSAL RECORDS

APPENDIX F – LIAISON WITH REGULATOR

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CORRECTIVE ACTION IMPLEMENTATION & VERIFICATION GREAT NORTHERN BREWERY No. P0440

June 2014 47065571 Issue 2

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EPA Impacted Land & Groundwater Risk Assessment Methodology

Report Reference

Report Date Status

1.1

PSA Report 09 November 2012 Final

1.2 DSA Report

Additional DSA Report

27 February 2013

08 May 2013

Final

Final

1.3 DQRA AEC7

DQRA AEC6

28 June 2013

2 December 2013

Final

Final

2.1

- - -

2.2 ROA AEC6 28 February 2014 Final

2.3 Corrective Action Design & Implementation Plan AEC6

25 March 2014 Final

2.4 Corrective Action Design & Implementation Plan AEC6

25 March 2014 Final

3.1

- - -

3.2 Corrective Action Implementation &Verification AEC6

19 June 2014 Final

3.3 - - -

STAGE 1: SITE CHARACTERISATION & ASSESSMENT

PRELIMINARY SITE

ASSESSMENT

DETAILED SITE

INVESTIGATION

QUANTITATIVE RISK

ASSESSMENT

STAGE 2: CORRECTIVE ACTION FEASIBILITY & DESIGN

OUTLINE CORRECTIVE

ACTION STRATEGY

FEASIBILITY STUDY &

OUTLINE DESIGN

DETAILED DESIGN

STAGE 3: CORRECTIVE ACTION IMPLEMENTATION & AFTERCARE

FINAL STRATEGY &

IMPLEMENTATION PLAN

ENABLING WORKS

CORRECTIVE ACTION

IMPLEMENTATION &

VERIFICATION

AFTERCARE

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June 2014 47065571 Issue 2

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1. INTRODUCTION

URS Ireland Limited (URS) is pleased to present this Corrective Action Implementation & Verification report to Diageo Ireland (the Client), for Area of Environmental Concern 6 (AEC6) located at the Diageo Great Northern Brewery, Dundalk (the site).

The site operates under an Integrated Pollution Prevention Control (IPPC) licence (Register No. P0440), issued by the Environmental Protection Agency (EPA). Diageo proposes to surrender this IPPC licence in 2014.

The site is located near the centre of Dundalk town, immediately east of Dundalk train station. Site location and layout plans are presented in Figures 1 and 2. AEC6 layout plan is presented in Figure 3.

This Corrective Action Implementation & Verification report has been completed in general accordance with the relevant sections of the Agency’s template entitled “Guideline Template for Corrective Action Implementation & Verification Report for the Environmental Protection Agency”.

1. BACKGROUND FROM STAGE 1 AND 2

URS completed a number of investigations at the site between 2009 and 20131,2,3,4,5,6.

The findings of these investigations with respect to AEC6 are summarised in the following sections.

1.1 Stage 1 - Preliminary Site Assessment (PSA)

URS completed a PSA at the site in 20123. The objective of the PSA was to identify potential environmental risk areas that may be associated with the site, and not addressed by previous investigations completed at the site. Based on the findings of the PSA, a detailed site assessment (DSA) was recommended for the eight APECs, including APEC6.

1.2 Stage 1 - Detailed Site Assessment (DSA)

URS completed a DSA4 at the site in January 2013. The DSA involved intrusive site investigation of eight APECs identified in the PSA.

With respect to APEC6, given the presence of petroleum hydrocarbon impact in groundwater at APEC6, it was considered an area of environmental concern (subsequently termed AEC6). The primary source of contamination in groundwater in AEC6 was considered to be weathered diesel oil observed in and around a hydrant

1 URS Ireland Limited (2010) Diageo Ireland – Great Northern Brewery, Dundalk – Soil and Groundwater Assessment 2 Diageo Great Northern Brewery, Dundalk, Groundwater Monitoring, 2011; Diageo Great Northern Brewery, Dundalk, Groundwater Monitoring, November 2011, Diageo Great Northern Brewery, Dundalk, Groundwater Monitoring, May 2012, Diageo Great Northern Brewery, Dundalk, Groundwater Monitoring, November 2013 and Diageo Great Northern Brewery, Dundalk, Groundwater Monitoring, January 2013 3URS Ireland Limited (2012) Great Northern Brewery (IPPC Register No. P0440), Preliminary Site Assessment Report, Ref: 47064016 4 URS Ireland Limited (2013) Detailed Site Assessment Report, Great Northern Brewery (IPPC Register No. P0440), Ref: 47065571 5 URS Ireland Limited (2013) Additional Detailed Site Assessment Report, Great Northern Brewery (IPPC Register No. P0440-01), Ref:47065571 6 URS Ireland Limited (2013) Detailed Quantitative Risk Assessment – AEC6, Great Northern Brewery (IPPC Register No. P0440-01), Ref:47065571

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June 2014 47065571 Issue 2

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chamber (originating from the Generator Building and an external sump). It was therefore recommended that the standing oil/water in the chamber be removed, the chamber be cleaned, and additional investigation be completed at AEC6.

1.3 Stage 1 - Detailed Quantitative Risk Assessment (DQRA)

URS completed additional investigation and DQRA6 at AEC6 between 3 July 2013 and 12 November 2013. The objectives of the work were further development of a robust conceptual site model (CSM) for AEC6, and assessment of the potential risk to human health (assuming commercial/industrial land use) and controlled waters receptors from the hydrocarbon contamination detected in AEC6. URS concluded the following with respect to contamination at AEC6:

• Light non aqueous phase liquid (LNAPL) was observed in wells MW401, MW402, MW403 and MW404 in the Generator Building and MW203 and MW12 east of the Generator Building;

• The source of the contamination (biodegraded diesel and lube oil) was considered to have been a reported spillage from the Standby Generator during its commissioning circa 1980 and inferred incidental spillages and leaks during the life of the Generator (over approximately 22 years, up to 2002).

• The presence of predominantly longer chained hydrocarbon compounds and the absence of BTEX compounds in groundwater samples indicated a fuel product which was degraded, relatively immobile and non-volatile;

• It was considered likely that the original spill resulted in a mobile and migrating LNAPL plume which spread laterally through the saturated zone. The lateral spreading of the LNAPL would have been driven by the pressure head of contamination coming from the Generator area. Once the primary source (the driving force for migration) had been removed, the LNAPL would stabilise;

• Given that the reported spill, which is considered to be the most significant source of contamination, occurred circa 1980 and the Generator has been out of commission since 2002, the LNAPL was considered unlikely to be actively migrating;

• Baildown test data indicated that some LNAPL could potentially be recovered by pneumatic or hydraulic means. However, only a limited thickness of LNAPL was observed (following the baildown test), within a small thickness of relatively permeable material, therefore recovery volumes would be small;

• Based on a commercial/industrial end use scenario, the DQRA indicated that the risks to current or future site workers from identified contaminants of concern (COC) in soil, soil vapour, groundwater and LNAPL underlying AEC6, was considered insignificant; and

• The DQRA indicated that risks to controlled waters receptors (groundwater and surface water receptors), at the site boundary and beyond the site, from identified contaminants of concern in soil, groundwater and LNAPL underlying AEC6, was considered to be insignificant.

Based on the findings of the additional investigation and DQRA (i.e. the LNAPL was considered likely to be stable or receding and risks to human health and controlled waters are considered insignificant), no further works were considered to be required to

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June 2014 47065571 Issue 2

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assess or remediate soil or groundwater in AEC6 and it was no longer considered an area of environmental concern.

1.4 Stage 2 - Remedial Options Assessment (ROA)

Following their review of the investigation and DQRA, the EPA issued a Request for Information (RFI) (dated 21 January, 2014) requesting a Remedial Options Assessment for AEC6 to explore remedial options and recommend a preferred remedial option. Given the DRQA had shown that risks to controlled waters receptors were considered to be insignificant and the LNAPL is considered stable, a meeting was held with the EPA and Diageo (31 January 2014) to discuss the Agency’s reasoning for requesting remediation at AEC6, and the objective of the remediation. The EPA indicated that, notwithstanding the DQRA findings, remediation was required given there is LNAPL present in groundwater at the site and that some of this could be recoverable. The EPA confirmed at the meeting that the objective of remediation at AEC6 is to remove the LNAPL to the extent that is practicable and feasible.

The ROA was submitted to the EPA in February 20147. Option 3 - excavation of impacted soil inside and outside the Generator Building, including demolition of the building, scored highest and this was adopted as the preferred remedial approach.

1.5 Stage 2 - Corrective Action Design and Implementation Plan (AEC6) and Enabling Works

The EPA provided approval of the ROA and Option 3 in their response (dated 12 March, 2014), with a number of conditions including the completion of a Corrective Action Design and Implementation Plan for AEC6. This was submitted in March 20148, with the objective of providing the EPA with sufficient detail of the corrective action design to be completed in ACE6, and how this would be implemented.

The Corrective Action Design and Implementation Plan for AEC6 was approved by the Agency on 10 April 2014 (contingent on a number of items, which have been incorporated into the AEC6 remediation works).

1.6 Stage 3 - Enabling Works

Prior to remediation of AEC6, enabling works were completed at the site, which involved the removal of the former Generator Building and associated electrical room by a Diageo-assigned contractor including. The concrete floor present inside the building was considered part of the remedial works, given the presence of hydrocarbon staining of the concrete groundcover, and is therefore discussed further within this report.

2. OBJECTIVE

Given the DQRA completed in Stage 1 showed that risks to human health and controlled waters receptors are considered to be insignificant, and the LNAPL is considered stable, the objective of remediation at AEC6 is to remove the LNAPL to the extent that is practicable and feasible, as agreed with the EPA.

7 URS Ireland Limited (2014) Remedial Options Assessment (AEC6), Great Northern Brewery (IPPC Register No. P0440-01), Ref:47065571.

8 URS Ireland Limited (2014) Corrective Action Design & Implementation Plan (AEC6), Great Northern Brewery (IPPC Register No. P0440-01), Ref:47065571.

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3. OUTLINE SCOPE OF WORKS

The AEC6 remediation was conducted between 15 April and 8 May, 2014. A scope of works was developed in accordance with the Corrective Action Design and Implementation Plan for AEC6 (i.e. Stage 2, Step 2.4), and to meet the above project objectives.

The main tasks completed, the actual duration compared with the original expected time-frames, and any significant variation from the Corrective Action Design and Implementation Plan, are provided in the table below.

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June 2014 47092707 Issue 2

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OUTLINE SCOPE OF WORK

Step Tasks Estimated Duration

Actual Date & Duration

Variation from the Corrective Action Design and Implementation Plan/Justification?

1 Decommissioning of monitoring wells located within, and on the north edge of the remedial excavation, including wells: MW12, MW201, MW203, MW204, MW205, MW401, MW402, MW403 and MW404 (see Figure 4a)

1 Day 1 Day 15/04/2014

Yes, MW205 also decommissioned, as it was located within the south east portion of the excavation

2 Trial pitting and collection of soils for waste classification (see Figure 4a) 1 Day 1 Day 17/04/2014

No

3 Break out of impacted concrete floor and foundations beneath the Generator Building and removal for off-site disposal (see Figure 4b)

5 Days 5 Days 18/042014, 23/04/2014, 24/04/2014, 25/04/2014 28/04/2014

Yes. It was originally planned to complete this task before Step 4. However, this was completed first for ease of access of site machinery and in order to removal impacted concrete before the excavation of ‘clean’ soil

4 Break-out of concrete and excavation of ‘clean’ soil outside the Generator Building. Stockpiling of this material in the designated area to the west of AEC6 (see Figures 4c and 4d)

5 Days 2 Days 28/04/2014, 29/04/2014

Yes. Stockpiling of this material was proposed to the west of AEC6, however, this material was placed to the north of the remedial excavation, given it was easily accessible to site machinery.

5 Excavation of recovery sump/trench in the area of MW203 (most impacted groundwater), and temporary dewatering of the excavation. Excavation of trial pits around the remedial excavation (outside the Generator Building) and completion of skimming to remove LNAPL mobilised during the excavation works (see Figure 4e)

3 Days 2 Days 29/04/2014, 30/04/2014

Yes. A sump was excavated in the location of MW203, and two additional sumps were excavated around the remedial excavation (Figure 4e). LNAPL was easily skimmed from the surface of the groundwater (see Photograph 18, Appendix A), however, due to slow LNAPL/groundwater recharge, the radius of influence of the LNAPL skimming was very localised, therefore, a series of trenches were excavated to drain impacted groundwater away from soils being excavated.

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OUTLINE SCOPE OF WORK

Step Tasks Estimated Duration

Actual Date & Duration

Variation from the Corrective Action Design and Implementation Plan/Justification?

LNAPL was removed from this water using a vacuum tanker (see Section 4.3 for further details groundwater management)

6 Excavation of impacted soils directly into trucks for off-site disposal (see Figure 4f)

3 Days 5 Days 30/04/2014, 01/05/2014, 02/05/2014, 06/05/2014, 07/05/2014

No.

7 Backfilling of excavation with the previously excavated ‘clean soil’, concrete (Step 1) and class 804 hardcore

3 Days 2 Days 07/05/2014, 08/05/2014

Yes. Approval from the EPA was not provided to reuse previously excavated ‘clean’ soil as backfill, so this was removed for off-site disposal. Diageo also decided not to reuse ‘clean’ concrete as back fill, so this material was sent for off- site disposal.

6 Installation of new concrete hardstanding 5 Days 2 days 30/5/14 3/6/14

No.

7 Post remediation groundwater monitoring and analysis following remediation works (see Figure 5)

2 Day 2 Days; 08/05/2014, 04/06/2014

No.

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4. DETAILED SCOPE OF WORKS

The following section describes the remedial technology adopted for the project and how the project was managed, in terms of operation, monitoring and maintenance of the remedial systems. Details on monitoring and verification during the works, is also provided.

4.1 Remediation Personnel

The following is the organisational structure for the remediation works:

The remediation works were managed by Diageo, with Declan Grennan as the Project Manager, supported by Ambrose Clarke of Byrne Ó Cléirigh Consulting.

The excavation contractors were Tinnellys Demolition, who was responsible for break-out of concrete and excavation of soils (the site engineer was John Carolan).

The waste contractor was Rilta Environmental Ltd. who managed the transportation and disposal of soil and groundwater.

Oversight of the remedial works and management of environmental controls was completed by URS. The URS field scientist was Rory Devlin and the environmental project manager was Sinead Fitzpatrick.

Diageo Ireland Site Owner

Declan Grennan Project Manager

Tinnelly Demolition Excavation Contractor

John Carolan Site Engineer

URS Ireland Limited Environmental Consultant

Sinead Fitzpatrick Environmental PM

Rilta Environmental Ltd. Waste Contractor

Colin Lennon Contracts Manager

EPA Regulator

Mary Sheehan IPPC Licence Inspector

URS Ireland Limited Environmental Consultant

Rory Devlin Environmental Field Scientist

Byrne Ó Cléirigh Licence Surrender Consultant

Ambrose Clarke Principal Advisor

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4.2 Health and Safety Considerations

All site preparation and excavation works were conducted in accordance with the Safety, Health and Welfare at Work (Construction) Regulations 2013 and amendments. As the site contains contamination of both soil and groundwater, appropriate Health and Safety measures were adopted, including personal protective equipment and hygiene facilities.

4.3 Remedial Technology and Design

The remediation of AEC6 involved the physical removal of the LNAPL body that was practicable and feasible, and recovery/disposal off site.

The remedial excavation covered an area of approximately 250 m2. This encompassed the Generator Building and external sump, and extended eastwards to MW203, MW12 and the Hydrant Chamber (Figure 3). The excavation area was subject to an engineering review prior to and during the excavation work in order to check the structural integrity of the excavation and of the surrounding buildings, as the area is located between the dry goods store to the east, the water treatment plant to the south, and the refrigeration room and hot water tank room to the west.

In terms of the structural integrity of the buildings, the excavation adjacent to the dry goods building (east) and the hot water tank room (west) maintained a clearance zone of approximately 1.5 m from the footing of these buildings.

As discussed in Section 3, the remedial excavation was conducted in a number of stages consisting of:

1. Groundwater well decommissioning.

2. Trial pitting and collection of soils for waste classification.

3. Concrete breakout beneath the Generator Building and removal of concrete off-site.

4. Concrete breakout and excavation of ‘clean’ soil and stockpiled to the north of AEC6 prior to removal.

5. Removal of LNAPL from groundwater using a vacuum tanker.

6. Excavation of impacted soils.

7. Backfilling of the excavation.

Further details on the remedial excavation sequence of events are provided in the table below and illustrated with a series of summary figures. Please see Figures 4a – 4f attached to the report for further details.

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REMEDIATION EXCAVATION – SEQUENCE OF EVENTS

Step Action Details

1 Well Decommissioning

Prior to commencement of remedial works (i.e. concrete break-out), monitoring wells located within and on the north edge of the proposed remedial excavation, including wells: MW12, MW201, MW203, MW204, MW205, MW401, MW402, MW403 and MW404 were decommissioned (Figure 4a). Further details are provided in Section 4.4.

2 Soil Classification As indicated in Section 5.3 of the Corrective Action Design and Implementation Plan, waste classification of site soils was required prior to excavation, in order to provide the receiving facility with sufficient characterisation of the waste soil.

This involved the excavation of three trial pits in AEC6 (Figure 4a) and the collection of soil samples for analysis. The results of this analysis and waste classification are provided in Section 4.5.

3 Concrete Breakout Beneath the Generator Building

The generator was built upon a reinforced concrete foundation plinth containing a central sump connected to an external sump on the northern side of the building. The concrete foundation plinth was approximately 2 m thick, and surrounding the plinth there was a number of service channels and a reinforced concrete floor slab, which had a thickness of between 0.2m and 0.6m (Figure 4b).

It was originally proposed that prior to off-site disposal, this concrete would be placed in a designated zone to the north of the remedial excavation area for break-up prior to removal from site. However, it was decided that this would be excavated and loaded directly into waiting trucks for off-site disposal, to avoid double handling of this material.

It was considered likely that some of the concrete beneath the Generator Building would not be impacted by hydrocarbons, particularly in the southern portion of the site (during the site investigation soils directly beneath the floor

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Step Action Details

slab at locations MW401 and MW402 were not impacted by hydrocarbons), and that this concrete material would be assessed by a URS field scientist to decide whether it would be segregated for off-site disposal or re-use. However, as a conservative measure, all concrete beneath the Generator Building was excavated for off-site disposal.

4 Concrete Breakout and Excavation of ‘Clean’ Soil

This step involved the breakout and excavation of concrete outside the Generator Building (Figure 4c). As the petroleum hydrocarbon contamination in this area was localised to the groundwater table (ranges between 0.61m and 1.69m bgl), the concrete in this area was not considered to be impacted and it was proposed that it would be reused to backfill the excavation following remediation (stockpiled to the west of AEC6). However, Diageo decided not to reuse this material and it was therefore excavated and loaded directly into waiting trucks for off-site disposal. No petroleum hydrocarbon impact was observed on the concrete (Photograph 9, Appendix A).

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Step Action Details

Following concrete break-out, excavation of underlying Made Ground (consisting of dense brown sandy gravel) in the east portion of the remedial excavation was completed. This was excavated to a depth of approximately 0.9 m bgl, and over an area of 60 m2 (Figure 4d).

This material was excavated above impacted soils and groundwater (Photograph 10-11, Appendix A) - contamination within the proposed remedial excavation was found to coincident with the entry of groundwater, which ranges between 0.61m and 1.69m bgl, with an average depth of 1m bgl - it was originally proposed that this would include all soils outside the Generator Building to an average depth of 1m bgl, however, as impacted soils were encountered to the east of the Generator Building at shallower depths, these were not included with the ‘clean soil’.

The above works were conducted in the presence of the URS field scientist, who visually assessed the soils during excavation, completed periodic screening using a photo ionisation detector (PID) and managed the segregation of this material. No impacted soils were encountered during the excavation of this material, and PID readings remained at 0ppm (see Section 6 for further details on environmental monitoring results).

This soil was stockpiled to the north of remedial excavation, covered with plastic sheeting and appropriately labelled (Photograph 12-13, Appendix A). It was originally proposed that it would be reused for backfilling of the excavation, however, approval from the EPA was not provided to reuse this material, so this was removed for off-site disposal.

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Step Action Details

5 Groundwater Skimming and Removal

Prior to commencement of excavation of impacted soils in AEC6, a recovery sump was excavated in the area of MW203 (where the most impacted groundwater was encountered), and two additional sumps were excavated around the remedial excavation (Figure 4e). As discussed in Section 3, LNAPL was easily skimmed from the surface of the groundwater (see Photograph 15-18, Appendix A), however, due to slow LNAPL/groundwater recharge, the radius of influence of the LNAPL skimming and lowering of the water table was very localised, therefore, a series of trenches were excavated to drain impacted groundwater from soils being excavated. A vacuum tanker was used to lower the water table and remove LNAPL from the impacted groundwater in these trenches.

‘Clean’ Soil

Impacted Soil

Soil Access Ramp

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Step Action Details

During pumping, groundwater levels were monitored by the URS field scientist in order to prevent them falling below bedrock level (approximately 1.75m), so that mobilisation of LNAPL down into the bedrock did not occur.

It was originally proposed that the vacuum tanker would be used on a stand-by basis, to remove impacted groundwater from the sump and to dewater the excavation as required. However, given the slow recharge of groundwater, and given how effective the vacuum tanker was at removing LNAPL and lowering the groundwater table, the vacuum tanker was retained for use on site during the entire period of impacted soil excavation. It had been proposed that a 5,000L bunded tank would also be present on site during the excavation works to temporarily hold pumped groundwater, however, this was not required as the 10,000L vacuum tanker proved sufficient to deal with groundwater inflow during excavation.

Oil/water collected from the tanker was transported to Rilta’s treatment facility, for appropriate recovery/disposal.

6 Excavation of Impacted Soils

Excavation of impacted soils above, at, and below, the water table was conducted in a sequence starting from beneath the Generator Building followed by the soils outside the building to the east. Soils in the southeast portion of the excavation were then removed. Finally, excavation of soils in the north portion of the excavation was completed, including these around the hydrant chamber. Figures 4f, i – iv, illustrates the sequence of events.

Soils were excavated and temporarily stockpiled in the northwest portion of the excavation for a few hours (awaiting return of trucks) and then loaded into waiting trucks for off-site disposal.

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Step Action Details

During these excavation works a number of concrete obstructions (foundations and beams) were encountered below the former Generator Building, and in the south portion of the excavation, at depths of 1.3 – 1.8 m bgl (1.6 – 2.1 m below the Generator Building floor). These obstructions were also broken out and excavated (see Figure 4f (ii)).

Soils were generally excavated to a minimum depth of 1.5 m (north portion of the excavation) and to a maximum depth of 1.9 m bgl, 2.2 m below the Generator Building floor (south portion of the excavation). The vertical extent of the excavation in the north portion was limited by the presence of bedrock.

In the south portion, the URS field scientist confirmed the remedial excavation depth based on field observations (absence of stained soils and LNAPL) (see

Impacted Soil

Stockpile of Impacted Soil awaiting track

Base of Excavation

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Step Action Details

Photographs 25-26, 29, 31, 32, 34, 36-38, Appendix A). Figures 4f, i – iv, illustrates the excavation depths.

It was indicated in the Corrective Action Design and Implementation Plan that the excavation depth inside the Generator Building could be up to 2.5 m below the Generator Building floor, based on site investigation works completed in this area. However, it was also noted that during drilling that it was difficult to log soils below the water table, as these were being brought up through impacted groundwater and therefore likely to be cross-contaminated. This was particularly the case during drilling in the Generator Building, as a small rig was used, due to access issues, which had a small borehole diameter (0.05m), resulting in poor soil recovery. The actual depth to the base of impacted soils was up to 2.1 m below the Generator Building floor (excavation depth in this area was up to 2.2m).

7 Backfilling Excavation

Following remediation, the remedial excavation was backfilled with imported class 804 hardcore. The backfill was compacted as required and was finished with concrete hardstanding between the 30 May and 3 June, in order to limit percolation of rainfall within the area9 (Photographs 39-42, Appendix A).

8 Post Remediation Groundwater Monitoring

Post remediation groundwater monitoring and analysis was completed at MW14, MW301, MW303, MW304, MW405, MW406, MW407, MW408 (Figure 5) immediately following the remediation works and after one month. Further details on the results are provided in Section 8.

9 The excavation was covered with plastic sheeting in the period between backfilling and concerting, to limit percolation of rainfall within the area.

Bedrock

Base of Excavation

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4.4 Environmental Monitoring Programme and Results

The following pollution control and monitoring measures were employed during the remediation of AEC6.

1. Decommissioning Wells – As discussed above, prior to commencement of remedial works (i.e. concrete break-out) monitoring wells located within, and on the north edge of the proposed remedial excavation, including wells: MW12, MW201, MW203, MW204, MW205, MW401, MW402, MW403 and MW404 were decommissioned. These works were conducted in accordance with the Environmental Agency’s guidance “Good practice for decommissioning redundant boreholes and wells” (October 2012). In accordance with the guidance, the wells were backfilled with a low permeability material (bentonite plugs) that will prevent vertical or horizontal movement of groundwater through or along the borehole. The headworks of wells inside the remedial excavation were then removed, during the excavation works under the supervision of the URS field scientist.

2. Environmental Monitoring - A URS field scientist was on site during the entire remedial excavation works to monitor and oversee the excavation works. Responsibilities of the field scientist included:

a. Recording daily activities, including a photographic record of works (Appendix A).

b. Monitoring of groundwater levels to prevent them falling below bedrock level (approximately 1.75m), so mobilisation of LNAPL into the bedrock does did not occur. This monitoring was completed in the trenches, and dewatering sumps. In order to assist in the monitoring of groundwater levels, fixed measuring sticks were placed around the excavation, which highlighted the maximum allowable draw down of groundwater (1.65m bgl). On the initial day of excavation groundwater was reduced to up to 1.7 m bgl, however, this was only allowed following removal of LNAPL from the surface.

c. During dewatering and excavation, groundwater in existing monitoring wells MW14, MW301, MW303, MW304, MW405, MW406, MW407, MW408 were checked on a daily basis with an interphase probe to monitor for the presence of LNAPL in these wells. No LNAPL was recorded in these wells during the remedial works (see Table 1 for results).

3. Dust Control – This included wetting down of roadways in the vicinity of the excavation. Given that trucks were not allowed enter the exposed excavation and given the removal of LNAPL from the excavation prior to excavation, significant impact of roadways with impacted soils did not occur (Photograph 8 and 22, Appendix A). However, as a precautionary measure, a jet wash was available on site to wash down truck, when required.

4. Excavation of Transportation of Impacted Soils – As previously discussed, in order to reduce the generation of impacted water during excavation the following measures were enacted:

a. A vacuum tanker was on hand to dewater the excavation and remove LNAPL when required.

b. The trucks that were used for transport of impacted soils had sealed truck beds, in order to prevent impacted water leaking during transport to the waste facility. The URS field scientist also carried out

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assessments of the trucks leaving site in order to check that no leaking of potentially impacted water was occurring.

4.5 Soil and Groundwater Waste Management

The following section provided details on additional waste classification of soils, the waste transfer docketing system, and details on the disposal of concrete, soil and groundwater during the remedial excavation.

4.5.1 Soil Sampling and Analysis

As indicated in the Corrective Action Design and Implementation Plan, additional waste classification of soils was required prior to the commencement of the remediation works, in order to provide the receiving facility with sufficient characterisation of the waste soil.

Three trial pits (TP2 – TP4) were excavated within the remedial excavation (Figure 4a) to a maximum depth of 1.6 m bgl (see Appendix B for trial pit logs). Soil samples of the most impacted soils were collected from a minimum depth of 0.9 m bgl to a maximum depth of 1.6 m bgl and placed into laboratory-supplied sample jars. The field scientist wore single-use disposable nitrile gloves during sampling. Soil samples were submitted to Jones Environmental Laboratories (JEL) in the UK for analysis.

In order to assess whether the material was non-hazardous or hazardous, and to establish the appropriate waste receiving facility, samples were analysed for the following parameters:

Solids

• Speciated total petroleum hydrocarbons (TPH) (including diesel range organics (DRO) and petrol range organics (PRO) and BTEX (Benzene, Toluene, Ethylbenzene and Xylene);

• Speciated 17 polycyclic aromatic hydrocarbons (PAHs);

• Metals (As, Ba, Cd, Cr, Cu, Hg, Mo, Ni, Sb, Pb, Se, Zn);

• Polychlorinated biphenyls (PCBs); and

• Total organic carbon (TOC).

Leachate

• Metals (antimony, arsenic, barium, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, selenium and zinc);

• Chloride, fluoride and sulphate;

• Phenol index;

• Dissolved organic carbon (DOC); and

• Total dissolved solids (TDS).

In terms of hazardous and non-hazardous waste classification, the soil analytical results were inputted into the HazWasteOnlineTM tool, which is designed and updated in

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accordance with the UK Environment Agency’s Technical Guidance WM2 V310. Following hazardous/non-hazardous waste classification, the non-hazardous sample results were compared to landfill acceptance criteria to establish a suitable disposal facility/landfill (i.e. inert or non-hazardous).

Based on the above, the soil samples collected from AEC6 remedial excavation were classified as follows:

WASTE CLASSIFICATION

Sample Depth (m) Date Sampled Waste Classification

Disposal Facility/Landfill

TP1 0.3-0.9 24/02/2014* Non-hazardous Non-hazardous

TP1 0.9-1.6 24/02/2014* Non-hazardous Non-hazardous

TP2 0.9 - 1.1 17/05/2014 Non-hazardous Non-hazardous

TP3 1.1-1.6 17/05/2014 Non-hazardous Non-hazardous

TP4 1.1-1.4 17/05/2014 Non-hazardous Non-hazardous

*Results provided in the Corrective Action Design and Implementation Plan

Waste analysis classification is presented in Table 2, with outputs from the HazWasteOnlineTM tool provided in Appendix C. Laboratory reports are provided in Appendix D.

As detailed in the Corrective Action Design and Implementation Plan, a sample collected during the environmental site investigation at MW404 from 1m below the Generator Building floor level was classified as hazardous waste. However, as previously noted, during drilling it was difficult to collect a representative soil sample below the water table, as soils were brought up through impacted groundwater and therefore cross-contaminated. This was particularly the case during drilling of MW404, which had a small borehole diameter (0.05m) and poor soil recovery.

Accordingly the hazardous waste classification of these soils is not considered representative of soils in this area, and samples collected from the trial pit (TP2) adjacent to MW404 are considered more representative (i.e. non-hazardous).

However, as a precautionary measure, it was decided that concrete and soils beneath the Generator Building, up to a depth of 1.5m below the floor level, were disposed as hazardous waste (further details on waste disposal are provided in Section 4.5.3).

4.5.2 Waste Management and Waste Transfer Docketing System

Disposal of waste soil was managed by Rilta Environmental Limited, with John Ryan Haulage Limited carrying out transport. Rilta’s role also included gaining approval from the National Transfrontier Shipment (NTFS) office to transport hazardous material from the site in line with the Shipment of Hazardous Waste Regulations 2011, SI 324 of 2011.

10 ‘Hazardous Waste – Interpretation of the definition and classification of hazardous waste, 3rd Edition, 2013.

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In order to check that the material excavation and transfer was completed in a controlled and transparent manner, a waste transfer docketing system was implemented by Rilta, and monitored by URS, during the course of the excavation. The docketing system included the following procedure:

• Each load was accompanied by either a Waste Transfer Form (WTF) (material being transfer to Rilta Hazardous Waste Transfer Station) or a Rilta Chain of Custordy Form for Waste Transfer (material being transfer to Greenstar, Knockharley Landfill), with the appropriate information filled in. The waste documents were signed by the truck driver and countersigned by the designated site official (Diageo personnel) before it left site to go to the waste facility for off-loading;

• The soil consignment was not allowed to unload until it was confirmed that the soil was from the site and the relevant waste document was available; and

• The soil consignment was then weighed on the weighbridge and the gross weight was recorded and printed on the weigh docket, along with the project customer name, truck registration number and waste document reference number. Each weighbridge docket was attached to the corresponding waste document form.

The vacuum tanker containing oily water was accompanied by appropriate documentation when leaving site. A Daily Work Form was signed by the Rilta driver truck driver and countersigned by the designated site official before it left site to off-load at the Rilta Hazardous Waste Transfer Station. An example of this documentation is provided in Appendix E.

A URS field scientist monitored the remedial excavation works on a full-time basis from 17 April to 07 May, 2014. On a daily basis, the URS field scientist checked the waste dockets in order to confirm that they were being correctly filled out.

The URS PM conducted an audit of the site during the remedial excavation works, in order to check that the above procedures were being implemented correctly. No significant issues were identified during this check and audit.

The waste transfer log and samples of the waste transfer documents/COCs and the counter-signed transboundary movements/ shipments of waste document, are provided in Appendix E.

4.5.3 Waste Disposal

Details on waste material removed from the site to Rilta and Greenstar during excavation works between 17 April and 07 May 2014 and to Greenstar between 16 and 20 May (‘clean’ soils) are provided in the table below (see Appendix E for waste transfer log).

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APPROXIMATE WASTE VOLUMES AND DISPOSAL ROUTES

Waste Disposal Site / Route Soils and Concrete

(tonnes) Oily water (tonnes)

Non-Hazardous Greenstar, Knockharley Landfill, Co. Meath (W0146-02)

48 (concrete) -

535 (soils) -

Hazardous Rilta Hazardous Waste Transfer Station, Rathcoole, Dublin 9 (W0192 - 03)

208 (soil and concrete)

93 (oily water11)

TOTAL 791 93

Following submission of the Corrective Action Design and Implementation Plan, estimates of the volume of soil and concrete to be excavated during the remediation works, were provided to the Agency. These estimates are greater than the actual volumes removed from the site, for the following reasons:

• The actual area of the excavation (250 m2) was less than estimated (300 m2) given the structural engineer’s recommendation for a clearance zone of approximately 1.5 m from the footing of buildings to the east and west;

• The original area estimated was based on site plans, but the actual area was measured on-site during the remediation works;

• The actual depth of excavation beneath the Generator Building was slightly less than estimated (2.5 m below the Generator Building floor), as impacted soils were shallower than expected in this area – as discussed previously, during the site investigation it was difficult to log soils below the water table in this area, as these were being brought up through impacted groundwater; the actual depth to the base of impacted soils was up to 2.1 m below the Generator Building floor (excavation depth in this area up to 2.2m);

• The actual depth of excavation in the north portion of the remedial excavation was less than estimated (1.7 m bgl), given shallow bedrock was encountered in this area (average depth of 1.5 m bgl); and

• The concrete and soil bulk densities used to estimate tonnages were conservative, for example, the soil bulk density used was 2 tonnes/m3, however, in reality this could have been as low as 1.5 tonnes/m3 depending on the moisture content of the soils.

5. SYSTEM PERFORMANCE

This section describes how the corrective action programme progressed compared with what was envisaged at detailed design stage, including details of changes made to optimise the performance, and also problems that were encountered, and how these

11 A large portion of the oily water would have been un-impacted groundwater, which was pumped from the excavation in order to lower the water table.

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were overcome.

Given the remediation involved the excavation of impacted soil and groundwater as opposed to an in-situ remediation system, no changes were made to optimise the remediation performance. However, in terms of progression of the programme relevant to the detailed design stage, the remedial excavation progressed in general accordance with the proposed programme (see Section 3) and no significant problems were encountered during the remediation works.

6. MONITORING RESULTS

A summary of the monitoring data collected during implementation of the corrective action programme is discussed below.

Checking of Monitoring Wells for LNAPL

During dewatering and excavation, groundwater in existing monitoring wells MW14, MW301, MW303, MW304, MW406, MW407, MW408 were checked on a daily basis with an interface probe to monitor for the presence of LNAPL in these wells. No LNAPL was detected in these wells during the remedial works (see Table 1 for results).

PID Monitoring Results

Screening of ‘clean soil’ was completed during excavation and stockpiling of this material. PID readings are as follows:

• CS1 – 0ppm (taken during excavation);



• CL SP1 – 0ppm (taken from the stockpile); and

• CL SP2 – 0ppm (taken from the stockpile).

This would indicate no ionisable compounds (i.e. volatile petroleum hydrocarbons) present in this material.

It was envisaged that soils from the base of the remedial excavation would also be screened using the PID, however, given soils at this depth were located below the water table it was not possible to collect an appropriate sample for screening. Generally PID results recorded were in the range of 20 – 30 ppm, however, the water-logged nature of the sample could have affected the readings, as the PID is sensitive to moisture.

Post Remediation Groundwater Monitoring

Post remediation groundwater monitoring was also completed following remediation, which is further discussed in below in Section 8.

7. LIAISON WITH THE REGULATOR AND THIRD PARTIES

Appendix F contains responses received from the Regulator regarding the ROA and during the remediation of AEC6, including:

• Response from the EPA on Remedial Options Assessment report;

• Response on the Corrective Action Design and Implementation Plan;

• Response to request for waste contractor approval;

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• EPA approval for waste contractors; and

• EPA approval notice for the disposal of ‘clean’ soil as non-hazardous wastes - Approval from the EPA was not provided to reuse previously excavated ‘clean’ soil as backfill, so this was removed for off-site disposal.

No liaison with third parties was conducted during the remediation works.

8. VERIFICATION

This section explores the quantitative measurement of the remedial works to validate its performance against the remedial objectives for the site.

As discussed, given the DQRA completed in Stage 1showed that risks to human health and controlled waters receptors are considered to be insignificant and the LNAPL is considered stable, the objective of remediation at AEC6 is to remove the LNAPL to the extent that is practicable and feasible.

The quantitative measurement of this LNAPL removal is discussed below in terms of the lateral and vertical extent of the final excavation, the quantity of soils/water removed, and the post-remediation groundwater monitoring.

Lateral Extent

The lateral extent of the remedial excavation covered an area of approximately 250 m2

(i.e. the footprint of the LNAPL plume). This encompassed the former Generator Building (which was demolished, so the remedial excavation could be completed beneath this building), the external sump, and extended eastwards to MW205, MW12 and the Hydrant Chamber (Figure 3).

Vertical Extent

The vertical extent of the remedial excavation extended to a minimum depth of 1.5 m and a maximum depth 1.9 m bgl (2.2 m below the Generator Building floor) (Figure 4f(iv)). The vertical extent of the excavation in the north portion was limited by the presence of bedrock. In the south portion the URS field scientist confirmed the remedial excavation depth based on field observations (absence of stained soils and LNAPL - see photographic record, Appendix A). The depth of the excavation and field observations are provided below.

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APPROXIMATE DEPTHS TO BASE OF EXCAVATION

Location Approximate depth (m bgl)

Field Observations

South west of excavation 1.9 No evidence of impact in

base of excavation

South of excavation 1.8 No evidence of impact in base of excavation

South east of excavation 1.6 No evidence of impact in

base of excavation Centre of excavation 1.5 Bedrock encountered

North west of excavation 1.6 Bedrock encountered

North of excavation 1.5 Bedrock encountered North east of excavation 1.5 Bedrock encountered

Quantity of Soils/Water Removed

The quantitative measurement of soils and groundwater removed from site is provided in the soil and groundwater disposal records. The records indicate that 791 tonnes of soil and concrete were removed from AEC6 for appropriate disposal. Furthermore, a total of 93 tonnes of oily water were removed from AEC6 for appropriate disposal. It is noted that a large portion of this oily water would have been un-impacted groundwater, which was pumped from the excavation in order to lower the water table.

Post Remediation Groundwater Monitoring

Following remediation, groundwater samples were collected from AEC6 from seven groundwater monitoring wells (MW14, MW301, MW303, MW304, MW405, MW406, MW407, MW40812, see Figure 5), on 08 May 2014, to confirm that the remedial works had not resulted in a deterioration of groundwater quality at the site. This monitoring was then repeated after one month (04 June 2014), to provide further reassurance that groundwater quality had not been impacted at the site from remediation activities.

The groundwater monitoring results for both monitoring rounds are provided in Tables 3 - 5, (laboratory reports are provided in Appendix D). The results indicate that TPH was less than the laboratory detection limit (0.01mg/l) in groundwater samples from MW14, MW301, MW303, MW304, MW406, MW408. TPH was detected at MW407 during both the May and June monitoring round at concentrations of 1.5mg/l and 0.27mg/l, respectively. However, previous TPH concentration detected in this well have been greater, with 7.5mg/l detected in September 2013. The results indicate that the remedial works did not result in a deterioration of groundwater quality at the site.

Based on the works completed during the remedial excavation in AEC6 and the results of the post groundwater monitoring, URS can confirm that the objectives of the remediation have been met.

12 It was also proposed to monitor MW405, however, a sample could not be collected, as this well was dry during both monitoring rounds.

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9. REINSTATEMENT

The remedial excavation was backfilled with imported class 804 hardcore. The backfill was compacted as required and, a few weeks, was finished with concrete hardstanding (see Figure 6 for cross section and Photograph 42, Appendix A). The excavation was covered with plastic sheeting in the period between backfilling and concreting to limit percolation of rainfall within the area (Photograph 40, Appendix A).

Services which had been isolated to facilitate excavation were reinstated and reconnected, as appropriate.

10. AFTERCARE PLANNING

The DQRA completed for AEC6 has shown that risks to human health and controlled waters receptors are considered to be insignificant. Notwithstanding that finding, removal the LNAPL and hydrocarbon-impacted soils to the extent that is practicable and feasible has been completed by Diageo. Post-remediation groundwater monitoring has shown no deterioration in groundwater quality in the area as a result of the excavations conducted. Accordingly, aftercare planning/reporting is not considered necessary.

11. CONCLUSIONS & RECOMMENDATIONS

Based on the remedial excavation works completed, the objectives of the corrective action programme have been met. AEC6 is no longer considered an area of environmental concern and no further works are considered to be required.

Respectfully submitted On behalf of URS Ireland Limited

Project Manager

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