for inspection purposes only. · ∙ contract 4 (m&e works) w 3,749,000 ∙ network (m3...

Attachments B.10 – F.2

Attachment B.10 - Proof of Funding ( – 2) Technical Scoping Report 2011 (Page 3 – 18) WWTP Improvement Programme Timeframe (Page 19)

Attachment C.1a - Operational Information Drawing – C1 WWTP Schematic

Attachment C.1.1 - Storm Water Overflows - Assessment Attachment C.1.2 - Pumping Stations Attachment C.2 - Outfall Design and Construction Attachment D.1 - Influent Monitoring Data, 2012 Attachment E.2 - Programme for Environmental Monitoring Attachment E.4a - Final Effluent Monitoring @ SW1, 2012 Attachment E.4b - Compliance with Monitoring Requirements and Treatment

Standards Attachment F.1 - Assessment of Impact on Receiving Surface or Ground

Water Attachment F.2 - Tabular Data on Drinking Water Abstraction Point(s)

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∙ Contract 4 (M&E Works) W 3,749,000

∙ Network (M3 Interface Works) W 1,060,000

Meath Grouped Towns & Villages Sewerage ∙ Contract 2 (Wastewater Treatment

Scheme1 Plant - DBO) S 30,801,000

∙ Contract 3 (Networks) S 10,245,000

∙ Contract 4 (Networks) S 13,306,000

Navan Mid-Meath Water Supply Scheme ∙ Contract 2 (Network & Reservoirs

- Carn Hill) W 13,741,000

∙ Contract 3 (Network - Southern Ring) W 6,373,000

∙ Network (M3 Interface Works) W 2,684,000

∙ Networks (Civil Works - N51) W 1,297,000

Offaly

Edenderry Sewerage Scheme ∙ Contract 1 Sewers & Watermains S 1,876,000

South Dublin

Boherboy Water Supply Scheme ∙ Contract 2 (Civil Works) W 34,553,000

∙ Contract 3 (M&E Works) W 1,152,000

Lucan Sewerage Scheme (SLI) ∙ Civil Works (Tobermaclugg

Stream Upgrade) S 7,711,000

Wicklow

Arklow Water Supply Scheme Phase 3 ∙ Contract 1A (Wellfield Development) W 1,942,000

∙ Contract 1B (Woodenbridge

Collection Main) W 751,000

∙ Contract 1C (Woodenbridge

Pumping Station) W 745,000

West Wicklow Water Supply Scheme Phase 1 ∙ Contract 2 (M&E Works - Blessington) W 1,380,000

Wicklow Sewerage Scheme ∙ Wastewater Treatment Plant - DBO S 24,409,000

Wicklow Town Water Supply Scheme ∙ Contract 3 (Network - Port Access W 5,887,000

and Town Relief Road)

TOTAL 477,640,000

1 Athboy, Donore, Duleek, Kilmainhamwood, Moynalty, Rathcairn, Rathmolyon and Summerhill

CONTRACTS TO START 2010 – 2012

Dublin City

North City Water Supply Scheme ∙ Network (Arterial Watermain)

Phases 1 & 2 W 6,900,000

North Docklands Sewerage Scheme ∙ Contract 1 (Spencer Dock

Pumping Station) S 6,430,000

∙ Contract 2 (Spencer Dock to

Ringsend Rising Main) S 3,619,000

∙ Contract 3 (River Liffey Services) S 3,708,000

∙ Contract 4 (Network Upgrade) S 9,463,000

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Scheme Name Contract Name W/S Estimated

Cost €

Water Services Investment Programme 2010-2012Attachment B10 Lower Liffey Valley Regional Sewerage Scheme

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Ringsend Main Lift Pumping Station ∙ Contract 2 (M&E Works - Pumping

Station Upgrade) S 4,200,000

∙ Wastewater Treatment Plant Upgrade S 74,000,000

Water Conservation Stage 3 Works ∙ Dublin Region Watermains

Rehabilitation Project (Dublin City)

Tranche 2 W 12,795,000

Dun Laoghaire/Rathdown

Dun Laoghaire Sewerage Scheme Phase 1 ∙ Contract 1 Civil Works (Carysfort -

Maretimo Stream) S 5,900,000

∙ Contract 2 (Network Upgrade -

Sandyford/Stillorgan Improvements) S 5,000,000

∙ Contract 3 (Network Upgrade -

Glasthule Environs) S 200,000

Shanganagh/Bray Sewerage Scheme ∙ Contract 2 (Network - Bray to

Shanganagh) S 6,900,000


Rehabilitation Project (Dun Laoghaire

- Rathdown) Tranches 2 & 3 W 20,899,000

Fingal

Balbriggan Water Supply Scheme Phase 1 (SLI) ∙ Network & Reservoir (High Level) W 4,900,000

GDRDP: Blanchardstown Sewerage Scheme ∙ Contract 1 (Network) S 2,300,000

∙ Contract 9 (Network) S 320,000

∙ Mulhuddart Bridge Works S 500,000

Leixlip Water Treatment Plant ∙ Water Treatment Plant - DB W 30,000,000

Malahide Water Supply Scheme (SLI) ∙ Civil Works (Malahide Reservoir) W 3,590,000

Portrane/Donabate/Rush/Lusk ∙ Wastewater Treatment Plant - DBO

Sewerage Scheme S 30,600,000


Rehabilitation Project (Fingal) Tranche 2 W 6,465,000

∙ Watermain Replacement

(Cottrelstown - Oldtown) W 720,000

∙ Watermain Replacement

(Kilshane - Glebe) W 2,000,000

∙ Watermain Rehabilitation (Swords) W 6,000,000

Kildare

Athy Sewerage Scheme ∙ Network Upgrade S 500,000

Ballymore Eustace Sewerage Scheme (SLI) ∙ Wastewater Treatment Plant S 3,545,000

Barrow Abstraction Scheme ∙ Contract 1 (Wastewater Treatment

Plant - DBO) W 25,500,000

∙ Contract 4 (Bagenalstown Lock

Upgrade) W 1,447,000

∙ Contract 2 (Network) W 18,000,000

∙ Contract 3A (Network) W 11,000,000

Kildare Sewerage Scheme ∙ Network S 4,000,000

∙ Wastewater Treatment Plant - DBO S 24,000,000

Lower Liffey Vallley Sewerage Scheme ∙ Wastewater Treatment Plant Upgrade S 17,500,000

21

Water Services Investment Programme 2010-2012Attachment B10 Lower Liffey Valley Regional Sewerage Scheme

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Attachment B10 Lower Liffey Valley Regional Sewerage Scheme

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ID Task Name Start Finish

1 Commencement Wed 12/01/11 Wed 12/01/11

2 Review of Works requirements Wed 12/01/11 Fri 21/01/11

3 Review by KCC Mon 24/01/11 Fri 28/01/11

4 Finalise contract scope Mon 31/01/11 Fri 04/02/11

5 Agree to proceed with prequal and tender docs KCC/ DEHLG Mon 07/02/11 Fri 05/08/11

6 Prequalification (if required) Mon 18/07/11 Fri 11/11/11

7 Prepare prequalification docments Mon 18/07/11 Fri 05/08/11

8 Approval of prequalification documents Mon 08/08/11 Fri 26/08/11

9 Advertise Contract Fri 26/08/11 Fri 26/08/11

10 Prequalification period Mon 29/08/11 Thu 06/10/11

11 Summary report on prequalification submissions Fri 07/10/11 Fri 04/11/11

12 Shortlist tenderers Mon 07/11/11 Fri 11/11/11

13 Preliminary contracts Mon 28/02/11 Fri 20/05/11

14 Flow and load survey tender & award Mon 28/02/11 Fri 25/03/11

15 Flow and load survey Mon 28/03/11 Fri 20/05/11

16 Ground survey tender and award Mon 14/03/11 Fri 08/04/11

17 Ground survey Mon 11/04/11 Fri 06/05/11

18 Tender Process Mon 08/08/11 Fri 22/03/13

19 Modify tender documents Mon 08/08/11 Fri 09/09/11

20 Tender document approval Mon 12/09/11 Fri 20/04/12

21 Finalise tender documents Mon 23/04/12 Mon 21/05/12

22 Tender period Tue 22/05/12 Fri 31/08/12

23 Report on tenders Mon 03/09/12 Fri 21/12/12

24 Issue Alcatel letters Mon 24/12/12 Fri 04/01/13

25 Standstill Period Mon 07/01/13 Wed 06/02/13

26 Approval of report on tenders Mon 24/12/12 Fri 08/02/13

27 Contract signing Mon 11/02/13 Fri 22/03/13

28 Construction Commencement Mon 25/03/13 Mon 25/03/13

29 Section 1 Construction Tue 26/03/13 Mon 30/12/13

30 Detailed design Tue 26/03/13 Mon 17/06/13

31 Site setup, fencing etc Tue 26/03/13 Mon 22/04/13

32 Construction of balancing tank Tue 09/04/13 Mon 15/07/13

33 Inlet PS and rising main Tue 23/04/13 Mon 12/08/13

34 Inlet works upgrade Tue 21/05/13 Mon 12/08/13

35 Diversion of inlet sewers and commissioning of balancing tank Tue 13/08/13 Mon 26/08/13

36 Construction of new primary treatment unit Tue 02/07/13 Mon 21/10/13

37 Upgrade of existing primary settlement tanks Tue 22/10/13 Mon 16/12/13

38 Diversion of flows to new PST and new FDC Tue 17/12/13 Mon 30/12/13

39 Provision of new of tertiary filter Tue 02/07/13 Mon 21/10/13

40 Modifications to 2 No. existing settlement tanks Tue 22/10/13 Mon 02/12/13

41 Commissioning of works for additional flows Tue 03/12/13 Mon 16/12/13

42 Completion of Section 1 Mon 16/12/13 Mon 16/12/13


44 New process tanks for plant expansion Tue 24/09/13 Mon 27/01/14

45 Draindown and upgrade of final settlment tanks Tue 24/09/13 Mon 04/11/13

46 Refurbishment of tertiary filters Tue 24/09/13 Mon 18/11/13

47 Aeration tank modifications / anoxic zones Tue 22/10/13 Mon 10/02/14

48 Modifications to sludge returrn/waste / recirculation Tue 14/01/14 Mon 10/03/14

49 Modifications to phosphorus removal system Tue 25/02/14 Mon 24/03/14

50 Modifications to existing site pipework and FDC's Tue 17/12/13 Mon 10/03/14

51 Expansion of sludge treatment capacity Tue 24/09/13 Mon 16/12/13

52 Modifications to control system Tue 11/02/14 Mon 21/04/14

53 Commissioning and testing of Upgrade works Tue 25/03/14 Mon 19/05/14

54 Completion of Section 2 Works Mon 19/05/14 Mon 19/05/14


56 New primary settlement unit Tue 20/05/14 Mon 22/09/14

57 New/modified process tanks for plant expansion Tue 23/09/14 Mon 03/11/14

58 Expansion of sludge treatment capacity Tue 17/12/13 Mon 10/02/14

59 Modifications to existing site pipework and FDC's Tue 11/03/14 Mon 05/05/14


61 Commissioning and initial testing of expanded works Tue 02/12/14 Mon 19/01/15



64 Construction of administration and control building Tue 04/11/14 Mon 23/02/15

65 Construction of workshop building Tue 27/01/15 Mon 20/04/15

66 Leachate/imported sludge acceptance facilities Tue 04/11/14 Mon 09/02/15

67 Upgrade to odour control system Tue 04/11/14 Mon 26/01/15

68 Covers for process tanks Tue 04/11/14 Mon 15/12/14


70 Landscaping, site roads etc. Tue 10/03/15 Mon 04/05/15

71 Commissioning and testing complete works Tue 05/05/15 Mon 15/06/15


73 Commencement of process proving (Section 5) Mon 15/06/15 Mon 15/06/15

12/01

26/08

25/03

16/12

19/05

19/01

15/06

15/06

Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug SQtr 1, 2011 Qtr 2, 2011 Qtr 3, 2011 Qtr 4, 2011 Qtr 1, 2012 Qtr 2, 2012 Qtr 3, 2012 Qtr 4, 2012 Qtr 1, 2013 Qtr 2, 2013 Qtr 3, 2013 Qtr 4, 2013 Qtr 1, 2014 Qtr 2, 2014 Qtr 3, 2014 Qtr 4, 2014 Qtr 1, 2015 Qtr 2, 2015 Qtr 3, 2015

Critical

Critical Split

Task

Split

Milestone

Summary

Inactive Milestone

Inactive Summary

Manual Task

Duration-only

Manual Summary Rollup

Manual Summary

Start-only

Finish-only

External Tasks

External Milestone

Progress

Lower Liffey Valley SS -WWTW Upgrade - Outline Contract Programme

Page 1

Project: Lower Liffey Valley WWTP Upgrade


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ATTACHMENT C.1a Operational Information Requirements The existing Leixlip Wastewater Treatment Plant is divided into two separate treatment streams – (a) Main Stream and (b) Intel Stream (a) Main Stream The Main Stream treats waste from the entire catchment including Straffan, Leixlip, Celbridge, Kilcock and Maynooth. This part of the plant has a design pe of 45,000 and the process may be divided as follows: (1) Inlet Works/Preliminary Treatment (a) Screening Effluent from the Leixlip Main Drainage System initially passes through a stone collection chamber. This chamber consists of a rectangular shaped tank where stones and additional large items settle out. Between the stone trap and the Main Inlet screens is the storm overflow weir, which is addressed later. The Main Inlet screens, three 6mm aperture J&A Hi-Flow screens, operate in a duty/standby mode with normally two screens in duty and one on standby. In the event of one screen failure the standby will be brought into operation. In the event of two screens failing, depending on influent flow, some wastewater may overflow the storm weir. Should all three screens fail then the screens will quickly become blocked and all the wastewater from the catchment will overflow the storm weir. The failure of any of the three inlet screens will activate a 24-hour dial out alarm. (b) Main Inlet Pumps Following screening the wastewater enters pump station (PS) 1. PS1 has three pumps in a duty/assist/standby arrangement. In the event of the failure of one of the pumps the standby will be activated. Two of the three pumps have a capacity of 191 to 238 l/sec each, while the standby has a capacity of 369 to 409 l/sec. If two pumps fail wastewater will backup and overflow the storm weir, the volume overflowing, if any, will be vary depending on rainfall conditions. During dry weather one pump is generally sufficient to pump all the wastewater. The failure of any of the three inlet pumps will activate a 24-hour dial out alarm.

Attachment C.1a Lower Liffey Valley Regional Sewerage Scheme

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(c) Grit Removal The wastewater is pumped from PS1 into the grit trap. Failure of the grit trap will result in its diversion by gravity to the next stage and no direct discharge to the aqueous environment will occur. (d) Flow Splitting After grit removal the influent wastewater is split with the bulk continuing on to the Main Plant Primary treatment stage and a contributory diverted to the Intel Stream. The split ratio is dictated by penstocks on both lines. This area operates by gravity so there will be no direct discharge to the aqueous environment. (2) Primary Treatment After preliminary treatment the wastewater passes through the two primary settlement tanks. The wastewater at this stage is basically allowed to settle thereby reducing the load on the next treatment stage. These tanks have a combined capacity of 3,196 m3. Failure in these tanks will result in the wastewater bypassing by gravity to the next stage thereby not allowing any direct discharge to the aqueous environment. (3) Secondary Treatment The primary supernatant enters Flow Distribution Chamber (FDC) 6 where it mixes with Returned Activated Sludge (RAS) prior to entering the two aeration tanks. This transfer to the aeration basins is achieved by gravity thereby not allowing any direct discharge to the aqueous environment. (a) Aeration zone The primary supernatant and RAS are aerated in two surface activated aeration tanks, two aerators per tank. The dissolved oxygen is maintained at 1.0 ppm O2 with Mixed Liquor Suspended Solids (MLSS) of approximately 2,400 mg/l. Ferric sulphate is added post aeration to allow phosphorous precipitation in the final settlement tanks. The MLSS exits the aeration tanks by gravity thereby not allowing any direct discharge to the aqueous environment. (b) Final settlement The Main Plant utilises three final settlement tanks as the final stage of treatment. After aeration the MLSS travels by gravity to PS5. From there the final settlement tanks A1 and A2 are gravity fed while final settlement tank A3 is pumped. The pumps supplying A3 operate on a duty/standby arrangement. Failure of both these pumps will result in all the MLSS going to settlement tanks A1 and A2. After final settlement the effluent flows by gravity, mixing with the filtered Intel effluent, to the single final effluent outfall at SW1-P.


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(c) Return activated sludge RAS from the final settlement tanks is returned by gravity to PS8 where it is pumped into FDC 6 and mixed with the primary supernatant. This pump station operates with two pumps in a duty/assist mode. Generally one pump is sufficient in PS8 however if both pumps were to malfunction sludge would built up in the settlement tanks eventually overflowing via the plant outfall, SW1-P. The failure of either of the two pumps will activate a 24-hour dial out alarm. (b) Intel Stream The Intel Stream treats wastewater from the Intel Ireland facility in Leixlip, their process and domestic contributions, and a contribution from the main catchment. The Intel facility typically discharges 7,000 to 8,000 m3/day with the catchment contribution adding an additional 4,000 to 7,000 m3/day. This part of the waste water treatment plant has a design pe of 35,000 and the process may be divided as follows: (1) Preliminary Treatment (a) Screening The Intel screening equipment comprises a J&A rotating bar interceptor screen followed by a J&A Beltafine Screen, 6mm aperture; both designed for a maximum flow of 270 l/sec. As only one screen is available a manually operated non-screened by pass channel is available. Screen failure accompanied by not manually opening the by-pass will result in wastewater overflowing the storm weir. Failure of the screen will activate an automatic dial out alarm. (b) Inlet pumps Following screening the inlet flow is pumped to the selector tank by means of three submersible pumps. Each pump is designed to pump a flow of 135 l/sec against a head of 9.7m. These pumps operate in a duty/assist/standby arrangement. Failure of two or more pumps will result in wastewater overflowing the storm weir. Failure of any of these three pumps will activate a 24-hour dial out alarm.


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(2) Aeration Zone (a) Selector tank Wastewater is initially pumped to a selector tank located directly upstream of the aeration basins. Raw wastewater and RAS mix in this anoxic tank thereby optimising conditions with a view to avoidance of bulking sludge problems in the aeration tanks. Wastewater exits the tank by gravity thereby failure here will not allow direct discharge to the aqueous environment. (c) Aeration basins Two aeration basins are utilised and the are designed as a plug flow system. An anoxic zone, for denitrification, is incorporated on the inlet side of the aeration basins. Fine bubble diffusion is used to maintain dissolved oxygen of approximately 2 ppm O2 and the MLSS is typically 3,500 mg/l. Ferric sulphate is added post aeration to facilitate precipitation of phosphate in the final settlement tanks. MLSS exits the basins by gravity so any failure would not result in a direct discharge to the aqueous environment. (d) Final Settlement Two final settlement tanks are in use. In normal operation flow from the aeration basins gravitates to FDC 3 where it is split equally between the two final settlement tanks. Following settlement the supernatant flows by gravity to the rapid gravity filter units. Thereby any failure here would not result in a direct discharge to the aqueous environment. (e) Activated sludge pumping RAS is returned to the selector tank from the settlement tanks by three return pumps located in PS10. These pumps operate in a two duty one standby mode. Failure of one of these pumps will result in the standby coming into operation. Failure of two or more of these pumps would eventually result in the loss of settled sludge from the settlement tanks. This sludge would flow by gravity to the tertiary filters. Failure of any of these three pumps will activate a 24-hour dial out alarm. (3) Tertiary (Rapid Gravity Filter Units) The treated secondary effluent from the settlement tanks flows by gravity to four tertiary filters. The filters provide final polishing of the treated wastewater before it combines with the treated wastewater from the Main Plant and is discharged to the Liffey at SW1-P. Failure or overloading of the filter units will lead to them being


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bypassed by gravity. The unfiltered wastewater will still combine with the Main Plant final effluent before discharge at SW1-P. (c) Storm Water Discharge As outlined above mechanical failure up and including both sets of inlet pumps and/or storm flow conditions will result in the loss of untreated wastewater to the storm water units. Storm water from both preliminary units’ travel by a shared pipe to PS3 where it is pumped into the storm tank. (1) PS3 PS3 consists of a submersible pump sump in which two submersible pumps are installed. Both pumps are capable of pumping 142 l/s at a head of 9.5m and operate in a duty/assist arrangement. The sump also contains a 300mm diameter overflow which discharges direct to the Liffey via SW2. Failure of both these pumps will result in the bypassing of the storm tank via this overflow. (2) Storm water holding tank The storm water holding tank has a storage capacity of 1,200m3 and is constructed in a rectangular shape giving an internal length of 30m thereby optimising sludge settling time. Settled sewage exits the tank by gravity and enters the Liffey at SW2. When conditions are favourable, i.e. storm flows from the catchment reduce, the tank is emptied via PS7 back to the Main Inlet. This is an automatic return which is activated when the forward flow from PS1 falls below a predetermined level. The SWO system, which discharges at SW2, does not comply with the definition of a storm water overflow. Currently the inlet works have a combined forward pumping capacity of 3DWF while the storm tank provides one hours storage of DWF. (d) Emergency Generator The site is equipped with an 1100kVA standby generator, which will automatically power up in the event of a failure in the incoming electricity supply. (e) Emergency Outfall The emergency outfall, SWP-PE, shown on Drawing Leixlip C1 is actually the outfall that was used during the last expansion of the plant, late 1990’s. Its value as an emergency outfall is minimal, as it should only come into service if the plant outfall, SW1-P, becomes physically blocked through for example its structural collapse.


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(f) On-site Laboratory Leixlip wastewater treatment plant has an on-site laboratory, which provides process monitoring and regulatory required effluent analysis. Monitoring routinely carried out relevant to this application is presented in the table below.

Parameter Analytical Method CBOD5 DO probe and 5 day incubation COD Digestion and spectrophometry Total Nitrogen Digestion and colorimetry Total Phosphorous Digestion and colorimetry Nitrate Colorimetry Nitrite Colorimetry Ammonia Nessler colorimetry pH pH meter Suspended solids Gravimetric Fluoride Colorimetry The site laboratory participates in the EPA Intercalibration Programme for BOD, COD and Suspended Solids. Summary Mechanical failure in both preliminary units, up to and including both sets of inlet pumps, may result in an overflow at the storm overflow weirs. Depending on the nature of the failure and duration wastewater may enter the aqueous environment via SW2. Any failure after the preliminary units may, depending on the nature of the failure, result in the discharge of partially treated wastewater/sludge via SW1-P. Critical areas are monitored and failure will activate a 24-hour dial out alarm system. The plant has a standby generator which will automatically start in the event of the incoming electricity failing.


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Kildare County Council

Water Services Section

Tel: 045-980362, Fax: 045-980359

Aras Chill Dara, Devoy Park, Naas, Co. Kildare, Ireland.

PROJECT:

DRAWING:

FILE NAME:

Scale:

Date:

Drawn by:

Checked:

Revision:

REVISIONS

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Comhairle Chondae Chill Dara

Lower Liffey Valley Regional Sewerage Scheme

Storm Water Overflow Assessment

December 2010

TOBIN CONSULTING ENGINEERS

Attachment C.1.1 Lower Liffey Valley Regional Sewerage Scheme

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Template rep 003

DCO 0084

REPORT

PROJECT: Lower Liffey Valley Regional Sewerage

Scheme

CLIENT: Kildare County Council

Áras Chill Dara,

Devoy Park,

Naas,

Co Kildare.

COMPANY: TOBIN Consulting Engineers

Block 10- 4

Blanchardstown Corporate Park

Dublin 15

www.tobin.ie


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Lower Liffey Valley Regional Sewerage Scheme – Storm Water Overflow Assessment

2135 i Rev B

DOCUMENT AMENDMENT RECORD

Client: Kildare County Council

Project: Lower Liffey Valley Regional Sewerage Scheme

Title: Storm Water Overflow Assessment

PROJECT NUMBER: 2135 DOCUMENT REF: 2135 SWO

Assessment-Rev B

B Issue For Client GW 20.12.10 DC 20.12.10 COK 20.12.10

Revision Description & Rationale Originated Date Checked Date Authorised Date

TOBIN Consulting Engineers


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2135 ii Rev B

TABLE OF CONTENTS

1 INTRODUCTION ...............................................................................1

2 EXECUTIVE SUMMARY ...................................................................1

3 STORM WATER OVERFLOW NO. 2 (SWO 2) .................................1

3.1 LOCATION – STORM WATER OVERFLOW NO. 2 ...................................... 1

3.2 CHARACTERISTICS OF OVERFLOW – SWO 2 .......................................... 1

3.3 STRUCTURAL DESCRIPTION – SWO 2 ...................................................... 2

3.4 VISUAL OR AESTHETIC IMPACT – SWO 2................................................. 3

3.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 2............................... 4




4.3 STRUCTURAL DESCRIPTION – SWO 3 ...................................................... 6

4.4 VISUAL OR AESTHETIC IMPACT – SWO 3................................................. 6

4.5 NEW PUMPING STATION FOR KILCOCK TOWN ....................................... 7

4.6 CONCLUSIONS AND RECOMMENDATIONS – SWO 3............................... 8




5.3 STRUCTURAL DESCRIPTION – SWO 4 .................................................... 10

5.4 VISUAL OR AESTHETIC IMPACT – SWO 4............................................... 10


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2135 iii Rev B

5.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 4............................. 11

6 STORM WATER OVERFLOW NO. 5 (SWO 5) ...............................11

6.1 LOCATION – STORM WATER OVERFLOW NO. 5 .................................... 11

6.2 CHARACTERISTICS OF OVERFLOW – SWO 5 ........................................ 11










8 STORM WATER OVERFLOWS NO. 7 (SWO 7) AND 8 (SWO 8)...16

8.1 LOCATION – STORM WATER OVERFLOWS NO. 7 AND 8 ...................... 16


8.3 STRUCTURAL DESCRIPTION – SWO 7 AND SWO 8 ............................... 19

8.4 VISUAL OR AESTHETIC IMPACT – SWO 7 AND SWO 8.......................... 19

8.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 7 AND SWO 8........ 20



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2135 iv Rev B






10 STORM WATER OVERFLOWS NO. 10 AND 11 (SWO 10, 11)...23

10.1 LOCATION – STORM WATER OVERFLOWS NO. 10 AND 11 ............... 23

10.2 CHARACTERISTICS OF OVERFLOW – SWO 10 AND 11...................... 23

10.3 STRUCTURAL DESCRIPTION – SWO 10 AND 11 ................................. 25

10.4 VISUAL OR AESTHETIC IMPACT – SWO 10 AND 11 ............................ 25

10.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 10 AND 11 .......... 26

11 STORM WATER OVERFLOW NO. 12 (SWO 12).........................27

11.1 LOCATION – STORM WATER OVERFLOW NO. 12 ............................... 27

11.2 CHARACTERISTICS OF OVERFLOW – SWO 12 ................................... 27

11.3 STRUCTURAL DESCRIPTION – SWO 12............................................... 28

11.4 VISUAL OR AESTHETIC IMPACT – SWO 12.......................................... 28

11.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 12 ....................... 29





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2135 v Rev B

















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2135 vi Rev B

APPENDIX 1 - DRAWINGS

Drawing no. 1 SWO 2 – general location





Drawing no. 6 SWO 7 and 8 – general location


Drawing no. 8 SWO 10 and 11– general location






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2135 1 Rev B

1 INTRODUCTION

Kildare County Council have commissioned TOBIN Consulting Engineers to carry out investigation for

identification and assessment of storm water overflows in Lower Liffey Valley sewerage network, in

accordance with the requirements as set out in Urban Waste Water Treatment Directive (91/271/EEC)

– Procedures and Criteria in relation to Storm Water Overflows (Department of Environment, Heritage

and Local Government - DOEHLG; 1995).

The surface water overflows are located on combined sewer network serving Lower Liffey Valley

Sewerage Scheme agglomeration (Leixlip, Celbridge, Maynooth, Kilcock and Straffan, Co. Kildare).

2 EXECUTIVE SUMMARY

14 of the existing Storm Water Overflow (SWO) structures and working conditions have been assessed

based on the existing available hydraulic data and on-site visual inspection. 7 of the assessed

overflows (SWO number 4, 6, 9, 10, 11, 12, 14) have meet DOEHLG requirements. Minor upgrade

works have been recommended for three overflow structures from this group (SWO number 9, 10 and

11).

7 remaining overflows (SWO number 2, 3, 5, 7, 8, 13, 15) have not meet the requirements and require

upgrade or other preventive actions to protect the receiving waters from excessive and unnecessary

sewage discharges. Three overflow structures from this group (SWO number 5, 7 and 8) have recently

became unnecessary and could be sealed off. SWO number 3 will be shortly replaced by a new

structure, built to DOEHLG requirements. It is recommended that detailed analysis using rainfall model

data will be undertaken in cases where DOEHLG conditions have not been met, to determine the exact

target parameters and define the best improvement solutions before any works commence on site.

3 STORM WATER OVERFLOW NO. 2 (SWO 2)

3.1 LOCATION – STORM WATER OVERFLOW NO. 2

The assessed storm water overflow number 2 (SWO 2) is located at Leixlip Waste Water Treatment

Plant (WWTP), southeast of Leixlip town, in Saint Catherine’s Park. The general location of the overflow

point is shown on Drawing no. 1.

3.2 CHARACTERISTICS OF OVERFLOW – SWO 2

The general characteristics of SWO 2 are compiled in the Table below.

SWO number (as per Waste Water Discharge Licence application)

2

Location Leixlip WWTP

Grid reference of overflow point (6E, 6N) – as surveyed on site

301542, 235824


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2135 2 Rev B

Technical description High level overflow pipe from storm water holding tank. 700mm diameter underground concrete pipe to precast concrete outfall chamber. Outfall from chamber located under water.

Description of operation Overflow operates when storm water holding tank at WWTP is full. The overflow discharges to the river.

Name of receiving waters River Liffey

River basin district Eastern RBD

Designation of receiving waters

Non sensitive

Dry weather flow rate in receiving waters

2.0m3 x sec-1

Maximum volume emitted (up to 5 year storm)

1,142m3 (theoretical volume, calculated for critical storm using 20-year time series rainfall data)

56,298m3 (actual monthly volume, measured by flow meter in November 2009)

SWO Control Type High level overflow pipe from storm water holding tank

Type of Flow Meter at SWO Ultrasonic, linked with SCADA system at WWTP

SWO event notification Not available

SWO 2 overflows from storm water holding tank to River Liffey. The capacity of the tank is 1,200m³. In

the event that storm water holding tank is exhausted, settled storm water can overflow via 700mm

diameter high level pipe, through outfall manhole chamber located on River Liffey bank. Overflow to the

river is located below water level and is not visible from the river bank. The overflow does not operate in

dry weather flow conditions, as observed during site visit on 9th of December 2010.

There is an ultrasonic flow meter located on overflow pipe. The readings from flow meter are recorded

on monthly basis. The recorded data show that there were 13 storm water spillage events through

SWO 2 in the last 22 months, with spillage volumes ranging from 56,298m3 to 1,229m3 per month.

3.3 STRUCTURAL DESCRIPTION – SWO 2

The storm water holding tank is a reinforced concrete enclosed overground structure. Overflow from the

tank is a high level pipe. The overflow to the river is an underground concrete pipe 700mm diameter

and concrete precast chamber. All visible elements of assessed SWO are in good structural conditions,

with no noticeable structural defects. The outfall is however located under water and it is not possible to

assess its structural condition without underwater examination. No flow problems resulting in backflow,

outflow restrictions or any other issues have been reported by WWTP staff.


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2135 3 Rev B

3.4 VISUAL OR AESTHETIC IMPACT – SWO 2

The assessed overflow is located in the area outside of public access. The outfall point of SWO is

hidden under water and is not visible from the river banks. The SWO does not cause visual or aesthetic

impact on surrounding environment. The elements of SWO 2 are shown in Figures 1 and 2.

Fig. 1 SWO 2: outfall chamber visible from river bank

Fig. 2 SWO 2: storm water holding tank


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2135 4 Rev B

3.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 2

Records indicate that there have been significant overflow events at SWO 2 in the past and that SWO

2 does not meet DOEHLG requirements in terms of discharge frequency. The majority of the recent

overflow events occurred in 2009, which has been recorded as an extremely wet period. It is clear that

the overflow events are as a result of storm water in the foul sewerage network. This has been

recognized in the past and efforts are underway to reduce the volume of storm water entering the

system.

As part of the Lower Liffey Valley Sewerage Scheme, a network rehabilitation contract was completed

in 2010. The works involved the rehabilitation of a significant amount of the network. It is envisaged

that this will reduce the frequency of overflow events at SWO 2. Coupled with this, further investigative

works are also planned to identify sources of storm water in other areas of the network, with following

rehabilitation works, if necessary.

In addition to the above, as part of the upgrading of the Leixlip WWTP, it is intended to provide a large

balancing tank, with the capacity of 4,170m3. All flows entering the Leixlip WWTP will be discharged to

the balancing tank. The tank will balance peak rates from diurnal flow variations and also provide

additional storm water storage for the rainfall events. These measures will allow SWO 2 to meet the

DOEHLG criteria, based on theoretical flow rate calculation results.



The assessed storm water overflow number 3 (SWO 3) is located at Rye River Walk in Kilcock. The

overflow is associated with existing pumping station. The existing pumping station and overflow will be

shortly decommissioned and replaced with new pumping station and overflow. The general locations of

existing and future pumping stations and overflow points are shown on Drawing no. 2.




3

Location Kilcock pumping station (Rye River Walk)


288871, 239578

Technical description High level overflow pipe from pump sump linked with storm water holding tank. 375mm diameter underground concrete pipe with flap valve at outfall.


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2135 5 Rev B

Description of operation Overflow operates when pump sump and storm water storage tank at Pumping Station are full. The overflow discharges to the river.

Name of receiving waters Rye Water



Non sensitive


0.05m3 x sec-1


149.2m3 (theoretical volume, calculated for critical 5 year return period storm with 1 hour duration)

256.9m3 (theoretical volume, calculated for critical 5 year return period storm with 6 hour duration)

SWO Control Type High level overflow pipe from pump sump (linked with storm water holding tank)

Type of Flow Meter at SWO Not available


SWO 3 overflows to Rye Water from pump sump linked with storm water holding tank. In the event that

storm water holding tank and pump sump is exhausted, water can overflow via 375mm diameter high

level pipe. The outfall point is located on Rye Water river bank, above water level. There is a flap valve

on the overflow pipe, at outfall to the river. The overflow does not operate in dry weather flow

conditions, as observed during site visit on 8th of December 2010.

Theoretical analysis was carried out of the existing storm water storage capacity at Kilcock pumping

station. The results show that spillage would occur for every 2 and 5 year storm return period of

durations ranging from 30 minutes to 12 hours. The overflow for 5 year storm return period of 1 hour

duration (design rainfall event used to determine the size of storm water holding tank, as required by

DOEHLG), has been calculated as 149.2m3. The highest overflow volume has been calculated for 5

year storm return period of 6 hours duration (256.9m3). The calculation results show that the existing

volume of storm water holding tank is inadequate, and the spillage events are very frequent.

The existing Kilcock Pumping Station pumps the wastewater from Kilcock onwards to Maynooth by

means of two pumps discharging through a 250mm diameter rising main of 3,450m length. Since the

existing pumps were installed wear and tear has significantly reduced their discharge capacity. The

current pumping capacity and storage capacity is inadequate to deal with both the flow rates and

volumes of combined foul and storm water flows.


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2135 6 Rev B


The pump sump and storm water holding tank are reinforced concrete enclosed underground

structures. Overflow from the pump sump is a high level pipe. The overflow to the river is an

underground concrete pipe 375mm diameter. All visible elements of assessed SWO are in good

structural conditions, with no noticeable structural defects.


The outfall point of SWO is located on the river bank and is visible from the adjacent land across Rye

Water river. The adjacent area is however outside of frequent public access, and overflow events do

not cause significant visual or aesthetic impact on surrounding environment. The SWO 3 is shown in

Figures 3 and 4.

Fig. 3 SWO 3 – outfall with flap valve, located on Rye Water river bank

Fig. 4 SWO 4 and old pumping station, visible from opposite river bank


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2135 7 Rev B

4.5 NEW PUMPING STATION FOR KILCOCK TOWN

The existing pumping station will be soon abandoned and replaced with newly constructed facility, with

increased pumping and storm water holding capacity. The new pumping station will be fitted with stand-

by power generator to make the station fully operational during power outage incidents, and telemetry

system to remotely notify the maintenance personnel about any recorded failures of the pumping

equipment. The station has been constructed in the western outskirts of the town. It is expected to

decommission the old station and begin the operations at new facility in early 2011.

New pumping station and outfall are shown in Figures 5 and 6.

Fig. 5 New Kilcock Pumping Station


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2135 8 Rev B

Fig. 6 Storm water overflow to Rye Water at new Kilcock Pumping Station


The existing SWO 3 operates very frequently and its activation level is below DOEHLG requirements.

The whole old station will be decommissioned and abandoned in the following months, therefore any

improvements of the existing storm water overflow characteristics would not be economically justified.

The new pumping station has been constructed with 450m3 storm water holding tank, which will prevent

overflows to the Rye Water river from rainfall events with a frequency of up to 1 in 5 years. The SWO

parameters at the new station meet DOEHLG requirements.



The assessed storm water overflow number 4 (SWO 4) is from Maynooth Pumping Station, located

northeast of Maynooth town, on Old Dunboyne Road. SWO 4 discharges to Rye Water river, at

Maynooth Fisheries grounds. The general location of the overflow point is shown on Drawing no. 3.




4

Location Fisheries grounds, Old Dunboyne Road


294466, 238712


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2135 9 Rev B

Technical description High level overflow pipe from storm water holding tank. 450mm diameter underground concrete pipe. Reinforced concrete headwall at outfall to the river.

Description of operation Overflow operates when storm water holding tank at Pumping Station is full. The overflow discharges to the river.




SAC 001398


0.05m3 x sec-1


No overflow for critical storm events with up to 1 in 5 years frequency (modelling results)

SWO Control Type High level pipe overflow from storm water holding tank



SWO 4 overflows to Rye Water from storm water holding tank. In the event that storm water holding

tank is exhausted, water can overflow via 450mm diameter high level pipe. The outfall point is located

at Maynooth Fisheries grounds, on Rye Water river bank, above water level. The overflow is located

downstream of water extraction point for fish ponds. There is a grating on the overflow pipe, at outfall to

the river. The overflow does not operate in dry weather flow conditions, as observed during site visit on

8th of December 2010.

The minimum overflow setting is determined by ‘Formula A’, which takes into account the dry weather

flow, the population and the industrial effluent. ‘Formula A’ for the overflow at the Main Maynooth

Pumping Station is calculated at 16,262m³/d or 0.188m³/s. ‘Formula A’ therefore sets the minimum flow

which must be either discharged by the pumps at Maynooth onwards to Leixlip or to be stored within

the system before overflows take place. Until recently the pumping and storage capacity at Maynooth

Pumping Station was only approximately 50% of that required by the ‘Formula A’ calculation. The

pumps and overflow settings were inadequate to meet the DOEHLG criteria. That resulted in frequent

storm water overflow incidents.

The Maynooth Pumping Station has been recently significantly upgraded, with construction works

commissioned in October 2010. The construction of a new pumping facility and emergency storm water

holding tank resulted in sufficient protection to the adjoining watercourses from storm water overflows.

The station has been also equipped with stand-by power generator and telemetry system.


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2135 10 Rev B

The storm water holding capacity has been determined by rainfall event analysis. The largest volume

projected to be overflowed has been calculated as 2,599m³, during Time Series Rainfall Event No. 22.

This has been additionally increased by safety factor of 10%. The capacity of the existing new storm

water holding tank is 2,850m³.


The storm water holding tank is an underground reinforced concrete enclosed structure. Overflow from

the tank is a high level concrete pipe. The overflow to the river is an underground concrete pipe 450mm

diameter, with reinforced concrete headwall structure at outfall point. All visible elements of assessed

SWO are in good structural conditions, with no noticeable structural defects.


The outfall point of SWO is located on the river bank and is visible from close distance. The adjacent

area is however outside of frequent public access, and overflow events do not cause significant visual

or aesthetic impact on surrounding environment.

The SWO 4 is shown in Figures 7 and 8.

Fig. 7 SWO 4 – grating at outfall to the river


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2135 11 Rev B

Fig. 8 SWO 4 – headwall structure at outfall to the river


The existing SWO 4 meets DOEHLG requirements. The new pumping station has been constructed

with 2,850m3 storm water holding tank, which will prevent overflows to the Rye Water river from

rainfall events with a frequency of up to 1 in 5 years.



The assessed storm water overflow number 5 (SWO 5) is located at Maynooth Castle grounds, in

Maynooth town centre. The general location of the overflow point is shown on Drawing no. 4.




5

Location Maynooth Castle, Maynooth


293643, 237676

Technical description 225mm ductile iron overflow pipe from foul sewer manhole chamber. Outfall to the stream, above water level.

Description of operation Overflow operates when inflow to the chamber exceeds maximum capacity of the downstream pipeline. The overflow


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2135 12 Rev B

discharges to the stream.

Name of receiving waters Lyreen Stream, tributary to Rye Water



Non sensitive


0.05m3 x sec-1 (Rye Water)


Not available

SWO Control Type High level overflow pipe from open channel in manhole chamber.



SWO 5 overflows to Lyreen Stream from foul sewer manhole chamber. In the event that the capacity of

downstream part of network is exhausted, water can overflow via 225mm diameter pipe. This overflow

is in fact an emergency outfall to the stream. There is no storm water storage capacity at overflow

chamber. The chamber with overflow is located at Maynooth Castle grounds. The outfall point is located

behind Castle’s wall, at the stream bank, above water level. The overflow does not operate in dry

weather flow conditions, as observed during site visit on 8th of December 2010.

Until recently the spillage incidents through SWO 5 were very frequent. The results of theoretical

analysis determined spillage for every 2 year storm return period of durations ranging from 30 minutes

to 12 hours. The overflow volume varied from 104m3 to 229 m3. The capacity of downstream section of

the network was by far inadequate and the DOEHLG criterion (‘Formula A’) was not meet.

The situation has changed when the new trunk line on Parson Street and Leinster Street was built.

Most of the flow from Castle Grounds pipeline has been diverted to the new trunk line. The flow rate in

the Castle Grounds has been greatly reduced, and no overflow incidents through SWO 5 have been

reported since then.


The overflow is a high level ductile iron pipe from concrete chamber. The section at Castle grounds is

underground. The final section is an overground pipe, with concrete block outfall point. All visible

elements of assessed SWO are in good structural conditions, with no noticeable structural defects.


The outfall point of SWO is located on the stream bank and is highly visible. The overflow incidents

cause significant aesthetic impact on surrounding environment. The outfall is located in the town center,


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2135 13 Rev B

with nearby college entrance and town amenities. When it operates, raw sewage is visible from the

bridge and adjacent properties located across the stream.

The SWO 5 is shown in Figure 9.

Fig. 9. SWO 5 – outfall to Lyreen Stream (open pipe at the bottom)


Until recently the existing SWO 5 has been operating on frequent basis and DOEHLG ‘Formula A’

criterion has not been met. Any overflow incidents through SWO 5 cause significant aesthetic impact on

surrounding environment. As the majority of flow from Castle Grounds pipeline has been recently

diverted to the new trunk line, the overflow structure could be probably abandoned and sealed off. In

case that Local Authority would wish to maintain the overflow at current location, it is recommended to

reconstruct it and locate the outflow pipe under water level, to hide it from public view. In the event that

overflow function will be retained, the existing overflow chamber should be examined, to determine if

any improvement measures are necessary. Any action should be confirmed by detailed analysis using

rainfall model data, to define the best solution.



The assessed storm water overflow number 6 (SWO 6) is located at Celbridge Main Pumping station, at

Castletown, east of Celbridge town. The general location of the overflow point is shown on Drawing no.

5.


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2135 14 Rev B




6

Location Celbridge Main Pumping Station, Castletown, Celbridge


297989, 233620

Technical description High level overflow pipe from storm water holding tank. 300mm diameter underground ductile iron pipe. Steel grating at outfall to the river.

Description of operation Overflow operates when storm water holding tank at Pumping Station is full. The overflow discharges to the river.




Sensitive


2.4m3 x sec-1






SWO 6 overflows to River Liffey from storm water holding tank. In the event that storm water holding

tank is exhausted, water can overflow via 300mm diameter high level pipe. The outfall point is located

on River Liffey bank, above water level. There is a grating on the overflow pipe, at outfall to the river.

There were numerous incidents of uncontrolled discharge through SWO 6 in the past, due to pumping

equipment failures. This has been however resolved following the recent pumping station upgrade, to

meet DOEHLG criteria. The increase of sewage pumping and storm water holding capacity provided

appropriate protection to the adjoining watercourses from storm water overflows. The capacity of two

newly constructed storm water holding tanks has been determined by rainfall event analysis. The new


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2135 15 Rev B

storm water holding structures will prevent overflows to the receiving waters from rainfall events with a

frequency of up to 1 in 5 years.

The existing available storage capacity, including two new storage tanks, wet well and inlet channel, is

471m3. The overall storage capacity will be shortly additionally increased to 732m3, by adoption of dry

and wet wells, making previously part of the old pumping station.

The pumping station is equipped with stand-by power generator and telemetry system.

The SWO 6 does not operate in dry weather flow conditions, as observed during site visit on 8th of

December 2010.


The overflow is a high level ductile iron pipe from storm water holding tank. The outfall point is located

on the river bank and covered by boulders. There is a steel grating at the outfall point. All visible



The outfall point of SWO is located on the river bank and is visible from close distance. The overflow

does not cause significant aesthetic impact on surrounding environment, however when it operates,

storm water could be visible from the adjacent river walk.


Fig. 10 SWO 6 – outfall from open pipe to River Liffey


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Fig. 11 SWO 6 – grating at outfall


The existing SWO 6 meets DOEHLG requirements. The pumping capacity and storm water holding

tank have been recently upgraded, to meet ‘Formula A’ criterion. Storm water holding tank capacity has

been increased to 471m3. The implemented measures will prevent overflows to River Liffey from rainfall

events with a frequency of up to 1 in 5 years. The storage capacity will be shortly additionally increased

by 261m3, to total capacity of 732m3, which will provide supplementary safety factor and further protect

the receiving waters from sewage discharges. Although overflow incidents could be visible from the

adjacent river walk, they will be rare enough to not to cause significant visual impact on surrounding

environment.

8 STORM WATER OVERFLOWS NO. 7 (SWO 7) AND 8 (SWO 8)

8.1 LOCATION – STORM WATER OVERFLOWS NO. 7 AND 8

The assessed storm water overflows number 7 (SWO 7) and 8 (SWO 8) are located on Castle Slip

Road, at Castletown, in eastern part of Celbridge town. The general location of the overflow points is

shown on Drawing no. 6.


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7

Location Castletown Gate Slip, Castletown, Celbridge

Grid reference of overflow point (6E, 6N)

297585, 233309

Technical description 300mm concrete overflow pipe from foul sewer manhole chamber. Outfall to the river. .

Description of operation Overflow operates when inflow to the sewer backs up (surcharge of downstream section). The overflow discharges to the river.




Sensitive


2.4m3 x sec-1


Not available

SWO Control Type High level overflow from manhole chamber





8

Location Castletown Gate Slip, Castletown, Celbridge


297584, 233306

Technical description 450mm concrete overflow pipe from foul sewer manhole chamber. Outfall to the river. .


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chamber. Outfall to the river. .

Description of operation Overflow operates when inflow to the sewer backs up (surcharge of downstream section). The overflow discharges to the river.




Sensitive


2.4m3 x sec-1


Not available

SWO Control Type High level overflow from manhole chamber



SWO 7 and SWO 8 at Castletown Gate Slip overflow to River Liffey from sewer manhole chambers. In

the event that the capacity of downstream part of network is exhausted, water can overflow via 300mm

diameter (SWO 7) or 450mm diameter (SWO 8) high level pipes. These overflows are in fact

emergency outfalls to the river. The overflows do not operate in dry weather flow conditions, as

observed during site visit on 8th of December 2010.

Until recently the spillage incidents through SWO 7 and SWO 8 were very frequent. This was most

likely related to network surcharge caused by insufficient pumping and storage capacity at Main

Celbridge Pumping Station (Castletown), located approximately 500m downstream of SWO 7 and 8

locations.

Another reported incidents at Castletown Gate Slip have been related to uncontrolled overflows through

manhole lid of chamber number 5304, located at the bottom of the road. The character of these

incidents suggests that they were caused by surcharge of downstream section of the network and

insufficient pumping and holding capacity at Castletown Pumping Station.

The risk of surcharge and back up from downstream pipelines has been reduced, thanks to the upgrade

works completed recently at Castletown Pumping Station. The increase of sewage pumping and storm

water holding capacity provided adequate protection to the adjoining watercourses from uncontrolled

storm water and emergency overflows. The new characteristics of the Pumping Station will prevent

overflows to the receiving waters from rainfall events with a frequency of up to 1 in 5 years.


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No surcharge incidents through SWO 7 and SWO 8 have been observed since upgrade works have

been commissioned at the Pumping Station.

8.3 STRUCTURAL DESCRIPTION – SWO 7 AND SWO 8

The overflows are high level underground concrete pipes from sewer chambers. All visible elements of

assessed storm water overflows are in good structural conditions, with no noticeable structural defects.

8.4 VISUAL OR AESTHETIC IMPACT – SWO 7 AND SWO 8

The outfall points of SW Overflows are located on the river bank and are hidden from public view.

Overflow incidents through SWO outfalls do not cause aesthetic impact on surrounding environment.

The manhole 5304 is located on public road, and any overflow incident through its lid causes significant

visual and aesthetic impact, with raw sewage overflowing to the road surface.

The SWO 7 and SWO 8 points are shown in Figure 12. Manhole 5304 is shown in Figure 13.

Fig. 12. SWO 7 and SWO 8 – location of outfall points to River Liffey


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Fig. 13. Manhole 5304

8.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 7 AND SWO 8

Until recently the existing SWO 7 and 8 have been operating on frequent basis and DOEHLG ‘Formula

A’ criterion has not been met.

The recent upgrade works at the downstream Castletown Pumping Station most likely reduced the risk

of surcharge and overflow incidents in the discussed area. It is possible that the existing emergency

overflows SWO 7 and SWO 8 would not be needed any longer, and could be abandoned and sealed

off. Detailed analysis using rainfall model data should be undertaken to determine the possible

improvement solutions.

Overflow incidents through manhole 5304 cause significant aesthetic impact on surrounding

environment, by uncontrolled discharge of raw sewage to the public road. To prevent uncontrolled

discharge incidents at this location, the standard ductile iron lid should be replaced with sealed and

lockable lid.



The assessed storm water overflow number 9 (SWO 9) is from Primrose Hill Pumping Station. SWO 9

is located on Newtown Road, in Celbridge town center, and discharges to River Liffey. The general

location of the overflow point is shown on Drawing no. 7.


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9

Location Newtown Road, Celbridge


297379, 232913

Technical description High level overflow pipe from foul sewer manhole chamber. 300mm diameter underground concrete pipe. Outfall from the pipe at the retaining wall.

Description of operation Overflow operates when sewer backs up, as a result of insufficient pumping or storm water holding capacity at Primrose Hill Pumping Station. The overflow discharges to the river.




Sensitive


2.4m3 x sec-1



SWO Control Type High level pipe overflow from foul sewer manhole chamber



SWO 9 overflows to River Liffey from foul sewer line, as a result of surcharge and back up from

Primrose Hill Pumping Station, located approximately 80m downstream of SWO point. In the event that

storm water holding capacity or pumping capacity at the station is exhausted, water can overflow via

300mm diameter high level pipe from the main trunk line. The outfall point is located in the retaining

wall, on River Liffey bank, above water level. The overflow does not operate in dry weather flow

conditions, as observed during site visit on 8th of December 2010.

In view of the sensitivity of the River Liffey (the location of the pumping station is upstream of the water

intake works at Leixlip), the Primrose Hill Pumping Station has been recently upgraded. A new storm


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water holding tank has been constructed. The existing storm water holding capacity is 289m³ (79m³ in

old tank and 210m³ in new tank), and provides 8 hours emergency storage. The tanks are underground

concrete enclosed structures, with high level overflows. The station has been also equipped with

stand-by power generator and telemetry system.


The overflow is a high level concrete iron pipe from foul sewer line. The outfall point is located in the

retaining wall. The end of the pipe is open and there is no grating or flap valve at the outfall point. The

visible part of assessed SWO is in good structural condition, with no noticeable structural defects.


The outfall point of SWO is located above water level. It is visible from the adjacent foot bridge. The

overflow incidents cause significant visual and aesthetic impact on surrounding environment, as raw

sewage discharge from the pipe at high level is visible from the public space.

The SWO 9 is shown in Figure 14.

Fig. 14 SWO 9 – outfall to River Liffey


The SWO 9 activation level meets DOEHLG requirements (‘Formula A’), however any overflow incident

causes significant visual and aesthetic impact on the surrounding environment. The outfall from the

overflow pipe is located 1 to 2m above water level, and is clearly visible from the adjacent footbridge.


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There is no flap valve on the overflow pipe, which could also cause odour problems. It is recommended

to upgrade the SWO discharge point and hide the outfall from public view, possibly under water.

10 STORM WATER OVERFLOWS NO. 10 AND 11 (SWO 10, 11)

10.1 LOCATION – STORM WATER OVERFLOWS NO. 10 AND 11

The assessed storm water overflows number 10 (SWO 10) and 11 (SWO 11) are located at Ballyoulster

Pumping Station, on Dublin Road, east of Celbridge town. The general location of the overflow points is

shown on Drawing no. 8.

10.2 CHARACTERISTICS OF OVERFLOW – SWO 10 AND 11



10

Location Ballyoulster Pumping Station, Celbridge


298651, 233374

Technical description High level overflow pipe from pump sump. 225mm diameter underground PVC pipe with open outfall to the stream.

Description of operation Overflow operates when pump sump is full. The overflow discharges to the stream.

Name of receiving waters Shinkeen Stream (tributary to River Liffey)



Sensitive


2.4m3 x sec-1 (River Liffey)


Not available

SWO Control Type High level overflow pipe from pump sump




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11

Location Ballyoulster Pumping Station, Celbridge


298650, 233378

Technical description High level overflow pipe from manhole chamber. 150mm diameter underground PVC pipe with open outfall to the stream.

Description of operation Overflow operates when there is a blockage at the inflow to pump sump and the network is surcharged. The overflow discharges to the stream.

Name of receiving waters Shinkeen Stream (tributary to River Liffey)



Sensitive




Not available

SWO Control Type High level overflow pipe from manhole chamber



SWO 10 overflows to Shinkeen Stream from the pump sump at the pumping station. In the event that

sump capacity is exhausted, water can overflow via 225mm diameter high level pipe. This can be

caused by excessive inflow to the pumping station or pumps failure. Outfall point is located on the

stream bank, in gabion retaining wall, approximately 1m above water level. There is no grating and no

flap valve on the overflow pipe at outfall to the stream. The overflow does not operate in dry weather

flow conditions, as observed during site visit on 8th of December 2010.

SWO 11 overflows to Shinkeen Stream from the manhole chamber located at the pumping station site,

immediately upstream of pump sump. In the event of blockage or surcharge at the inlet to the pump

sump, sewage can overflow via 150mm diameter high level pipe. Outfall point is located on the stream

bank, in gabion retaining wall, approximately 2m above water level. Outfall of SWO 11 is approximately


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1m higher than outfall of SWO 10. This means overflow events through SWO 11 are not resulted by

pump sump overload. There is no grating and no flap valve on the overflow pipe, at outfall to the

stream. The overflow does not operate in dry weather flow conditions, as observed during site visit on

8th of December 2010.

The Ballyoulster Pumping Station is located on a small site adjacent to the Shinkeen Stream and

serves the Ballyoulster Housing Estate and the Industrial factory on Dublin Road. The available storm

water storage at the pumping station is limited to pump sump only. There is no information on how

frequently the overflow operates or associated spill volumes. There is also no emergency storage on

site. DOEHLG ‘Formula A’ at Ballyoulster Pumping Station is estimated at 0.008m³/s. Pumping capacity

is 0.01m³/s, and exceeds ‘Formula A’ value.

Because of the site restrictions it is not possible to construct inflow storage facilities to provide any

emergency retention capacity. The station however has been recently upgraded with telemetry system

and stand-by power generator on site, to come into play when there is a power outage. The upgrade

works have considerably reduced risk of uncontrolled overflow incidents through SWO 10.

10.3 STRUCTURAL DESCRIPTION – SWO 10 AND 11

The overflows are high level PVC open pipes, with outfalls in gabion retaining wall, at the stream bank.

All visible elements of assessed overflows are in good structural condition, with no noticeable structural

defects.

10.4 VISUAL OR AESTHETIC IMPACT – SWO 10 AND 11

The outfall points of SWO 10 and 11 are located above water level, and could be visible by pedestrians

from the Dublin Road bridge and from the property located across the stream from the pumping station.

Because of relative remoteness of the discussed area, the overflows do not cause significant aesthetic

impact on surrounding environment.

The SWO 10 and 11 are shown in Figure 15.


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Fig. 15 SWO 11 (150mm pipe, foreground) and SWO 10 (225mm pipe, background)

10.5 CONCLUSIONS AND RECOMMENDATIONS – SWO 10 AND 11

The existing SWO 10 and 11 meet DOEHLG requirements in terms of ‘Formula A’ criterion. Pumping

capacity is over 10 times higher than 6 DWF inflow rate. Recent installation of telemetry system and

stand-by power generator on site significantly reduced the risk of unnecessary spillages. Large reserve

of pumping capacity means that pumps are adequate to handle most of rainfall events.

There is no emergency storage available at pumping station site. It is not possible to build the storage

within pumping station boundaries, because of very limited available area. In the future the storage tank

could be possibly built upstream of the pumping station. The most convenient place for underground

structure seems to be a green area at the entrance to Ballyoulster housing estate.

It is possible that SWO 11 could be abandoned and sealed off. As an overflow from foul sewer manhole

chamber, it increases the risk of pollution in the receiving waters, by likely uncontrolled discharge of raw

sewage. The discharge function of SWO 11 is in principle doubled by the function of SWO 10 –

overflow from the pump sump. Overflow from SWO 10 has also lesser impact on the quality of receiving

waters, as the water would be partly settled in the pump sump, before discharge to the stream. It is

recommended to carry out hydraulic calculations to confirm the proposed solution.

In any case it is recommended to install flap valves on the outflow pipes to the stream. This will greatly

reduce any possible odour emissions from the pipes.


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The assessed storm water overflow number 12 (SWO 12) is located at Temple Mills Pumping Station,

Abbey Farm, in southern part of Celbridge town. The general location of the overflow point is shown on

Drawing no. 9.




12

Location Temple Mills Pumping Station, Abbey Farm, Celbridge


296933, 232428

Technical description High level overflow pipe from pump sump. 300mm diameter underground ductile iron pipe. Flap valve at outfall to the river.

Description of operation Overflow operates when capacity of pump sump at the pumping station is exhausted. The overflow discharges to the river.




Sensitive


2.4m3 x sec-1


Not available

SWO Control Type High level pipe overflow from pump sump



SWO 12 overflows to River Liffey from the pump sump at the pumping station. In the event that sump

capacity is exhausted, water can overflow via 300mm diameter high level pipe. This can be caused by

excessive inflow to the pumping station or pumps failure. Outfall point is located on the river bank,


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above water level. There is a flap valve on the overflow pipe at outfall point. The overflow does not

operate in dry weather flow conditions, as observed during site visit on 9th of December 2010.

The Temple Mills Pumping Station is located on a small site on the banks of River Liffey, south of Clane

Road in Celbridge. The available storm water storage at the pumping station is limited to pump sump

only. There is no information on how frequently the overflow operates or associated spill volumes.

DOEHLG ‘Formula A’ at Temple Mills Pumping Station is estimated at 0.019m³/s. Pumping capacity is

0.03m³/s, and exceeds ‘Formula A’ value.

Because of the site restrictions it is not possible to construct sufficient emergency storage facilities to

store excessive inflow and flows during times of power outage. The station however has been recently

upgraded with telemetry system and stand-by power generator to come into play when there is a power

outage. These elements have considerably reduced risk of uncontrolled overflow incidents through

SWO 12.


The overflow is a high level ductile iron pipe from pump sump. There is a flap valve at the outfall point.

All visible elements of assessed SWO are in good structural conditions, with no noticeable structural

defects.


The outfall point of SWO is located on the river bank and covered by greenery, in the area generally

inaccessible to public. The overflow does not cause aesthetic impact on surrounding environment.


Fig. 16 SWO 12 – flap valve at outfall pipe


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Fig. 17 SWO 6 – outfall at pumping station site


The existing SWO 12 meets DOEHLG requirements in terms of ‘Formula A’ condition. Pumping

capacity is over 50% higher than 6 DWF inflow rate. There is no emergency or storm water holding

storage available at pumping station site. It is not possible to build the storage within pumping station

boundaries, because of limited available area. Recent installation of stand-by power generator on site

eliminated the risk of unnecessary spillages in the event of power cut.



The assessed storm water overflow number 13 (SWO 13) is located at Mill Lane, in southeastern part

of Leixlip town. The general location of the overflow point is shown on Drawing no. 10.




13

Location Mill Lane, Leixlip


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301148, 235876

Technical description High level overflow pipe from foul sewer manhole chamber. 225mm diameter underground concrete pipe. Outfall from chamber located above water level. Flap valve at outfall

Description of operation Overflow operates when sewer backs up, as a result of insufficient capacity of downstream section of the network. The overflow discharges to the stream.

Name of receiving waters Silleachain Stream (tributary to River Liffey)



Non sensitive




Not available

SWO Control Type High level overflow pipe from foul sewer manhole chamber



SWO 13 overflows from foul sewer manhole chamber located on 375mm pipeline, to Silleachain

Stream. In the event that the capacity of downstream part of network is exhausted, water can overflow

via 225mm diameter pipe. This overflow is in fact an emergency outfall to the stream. The chamber with

overflow is located on private property. Overflow to the stream is located in the public space, above

water level and is visible from the adjacent road and footpath. The overflow does not operate in dry

weather flow conditions, as observed during site visit on 9th of December 2010.

There is no information on how frequently the overflow operates or associated spill volumes. DOEHLG

‘Formula A’ of downstream section of 375mm diameter Mill Lane sewer is estimated at 0.06m³/s. The

maximum capacity of the downstream section of sewer is 0.072m³/s. The downstream sewer capacity

is greater than the ‘Formula A’ requirement. However the downstream capacity is influenced by the

inflow to the Leixlip WWTP as outlined below.

The 375mm diameter sewer from Mill Lane enters the Inlet of the Leixlip Wastewater Treatment Plant at

the same invert as the 750mm diameter main inlet sewer. The 375mm diameter sewer has a fall of

0.652m over a length of 366m, which means that if the 750mm diameter sewer is flowing close to full

bore then the 366m length of 375mm diameter sewer would be surcharged. The surcharging of the


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375mm diameter sewer causes near stagnant flows, which results in deposition of silt at the low

velocities, as well as upstream overflows through SWO 13 on Mill Lane.


Overflow from the manhole chamber is a high level 225mm diameter concrete pipe. The overflow to the

stream is located in a stone wall, at the stream bank, above water level. There is a flap valve at outflow

point. All visible elements of assessed SWO are in good structural conditions, with no noticeable

structural defects.


The outfall point of SWO 13 is located above water level and is visible from the adjacent footpath and

Mill Lane road. The overflow incidents cause significant visual and aesthetic impact on surrounding

environment, as raw sewage discharge is visible from the public space.


Fig. 18 SWO 13: flap valve at the outfall point.


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Fig. 19 Silleachain Stream at Mill Lane. SWO 13 visible behind 750mm diameter crossing sewer, at the right.


The existing SWO 13 does not meet DOEHLG requirements. While theoretical activation level meets

DOEHLG criterion and downstream sewer capacity is greater than the ‘Formula A’ requirement, other

influences result in overflows occurring below the ‘Formula A’ setting. The overflow incidents through

SWO 13 are caused mainly by insufficient velocity and surcharge of inlet to the downstream section of

375mm diameter pipeline, between Mill Street and Leixlip Waste Water Treatment Plant, located

approximately 380m downstream of SWO 13.

In order to prevent near stagnant flows in this sewer and overflows through SWO 13, the inlet to the

Leixlip Wastewater Treatment Plant should be reconstructed to allow a free discharge from the inlet

pipes. This work could form part of the contract for the Upgrading of the Leixlip Treatment Plat when a

new inlet balancing tank and pumping station would be constructed as per the recommendations of

other preliminary report studies. Detailed design and calculations must be carried out, to determine the

exact solutions and target parameters.



The assessed storm water overflow number 14 (SWO 14) is located at Straffan Pumping Station, east

of Straffan village. The general location of the overflow point is shown on Drawing no. 11.


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14

Location Straffan Pumping Station, Lodgepark, Straffan


292824, 229606

Technical description High level overflow pipe from storm water holding tank. 300mm diameter underground ductile iron pipe. Flap valve at outfall to the stream.

Description of operation Overflow operates when capacity of storm water holding tank at the pumping station is exhausted. The overflow discharges to the stream.

Name of receiving waters Liffey Water stream (tributary to River Liffey)



Sensitive




Not available




SWO 14 overflows to Liffey Water stream from storm water holding tank at the pumping station. In the

event that storm tank capacity is exhausted, water can overflow via 300mm diameter high level pipe.

Outfall point is located on the stream bank, above water level. There is a flap valve on the overflow

pipe, at outfall to the stream. The overflow does not operate in dry weather flow conditions, as observed

during site visit on 9th of December 2010.

The storm water holding tank at pumping station has a storage capacity of 100m³. The storage system

provides protection to the water quality in the River Liffey in the event of high flows caused by heavy

rainfall, infiltration through sewer connection pipelines located in private property or temporary pump

failure at the pumping station. The provision of storage at Straffan also allows for temporary cessation


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of pumping onwards to Celbridge, if there is a problem at the main pumping station at Castletown in

Celbridge, and there is a need to keep the available storage there for incoming flows from Celbridge

itself, so as to prevent unnecessary overflows to the River Liffey.

In order to check the adequacy of the existing storage capacity with respect to high flows caused by

heavy rainfall a series of rainfall events were used. A twenty year Time Series Rainfall was generated

for Straffan, based on daily rainfall records for the period 1979 to 1999 supplied by Met Eireann. The

model of the proposed Straffan Main Drainage System and Pumping Station was analysed under seven

selected critical storms from the Time Series data. The analysis shows that there would be no overflow

from the storage system during seven critical time series events. As a result, SWO frequency level

meets the DOEHLG criteria: no overflow incidents to the receiving waters from rainfall events with a

frequency of up to 1 in 5 years.

Because of the importance of water quality in the River Liffey for water abstraction at Leixlip, a

telemetry system and stand-by power generator have been provided at Straffan Pumping Station. In the

event of a prolonged power outage there is a facility to maintain the pumping station operational and

protect the river quality.


The overflow is a high level ductile iron pipe from storm water holding tank. The outfall point is located

on the stream bank, in a concrete brick headwall. There is a flap valve at the outfall point. All visible



The outfall point of SWO is located on the stream bank and is partly covered by greenery. It is located

in the area generally inaccessible to public. The overflow incidents do not cause aesthetic impact on

surrounding environment, however water flow in the stream during dry weather is almost stagnant, as

observed during site visit. Any overflow incidents in dry weather can cause odour and local ground

pollution problems, as the overflow may not be sufficiently diluted with stream flow.



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2135 35 Rev B

Fig. 20 SWO 14 – flap valve at outfall pipe

Fig. 21 SWO 14 – outfall and pumping station site


The existing SWO 14 meet DOEHLG requirements in terms of activation frequency, and does not

cause visual and aesthetic impact on surrounding environment. There is very low flow velocity in the

Liffey Water stream, which could cause problems with dry weather discharges (no proper dilution with


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2135 36 Rev B

stream waters). The station is however equipped with stand by power generator and telemetry system,

therefore risk of uncontrolled spillages is minimized.



The assessed storm water overflow number 15 (SWO 15) is located on Pound Street, in Leixlip town

centre. The general location of the overflow points is shown on Drawing no. 12. This overflow has not

been included in the original Waste Water Discharge License application from December 2007.



SWO number 15

Location Pound Street, Leixlip


300413, 235863

Technical description High level overflow pipe from foul sewer manhole to storm culvert. Outfall located above water level, at river bank.

Description of operation Overflow operates when sewer backs up, as a result of insufficient capacity of downstream section of the network. The overflow discharges to the river.




Non sensitive


0.05m3 x sec-1 (Rye Water, approximate)



Not available

SWO Control Type High level overflow pipe from foul sewer manhole chamber



SWO 15 overflows from foul sewer manhole chamber no. 4801, to the storm culvert and then to Rye

Water river. This overflow is in fact an emergency outfall to the river. It has been constructed after


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2135 37 Rev B

numerous flooding incidents in the downstream part of the network, of which the most serious

happened in January 2009. After several days of snowfall followed by heavy rains, the manhole located

at the entrance to Leixlip Castle, immediately upstream of Rye Bridge, surcharged and flooded the

entrance to the Castle. Inspection chambers in the adjacent garden also surcharged causing extensive

flooding in the vicinity of the house. The flooding was mainly caused due to insufficient capacity of pipe

traversing the Rye Water river at Rye Bridge and inadequate capacity of the network downstream of

Pound Street.

The discussed overflow has been designed such that it only comes into operation during significant

storm events whereby the overspill will be significantly diluted with surface waters.

The outfall to the river is located in the public space, above water level and is visible from the footpath

along Rye Water. The overflow does not operate in dry weather flow conditions, as observed during site

visit on 9th of December 2010. There is no information on how frequently the overflow operates or

associated spill volumes.


Overflow from the manhole chamber is a high level pipe, to the storm stone culvert. The overflow to the

river is located in a stone wall, at the river bank, above water level. There is no flap valve at outflow

point and no grating. All visible elements of assessed SWO are in good structural conditions, with no

noticeable structural defects.


The outfall point of SWO 15 is located above water level and is visible from the adjacent footpath, along

Rye Water river. The overflow incidents can cause some visual and aesthetic impact on surrounding

environment, however this overflow will come into operation only during heavy rainfall events, where

foul sewage spill will be significantly diluted with storm water.



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2135 38 Rev B

Fig. 22 SWO 15: surface water culvert combined with foul sewer overflow

Fig. 23 SWO 15 to Rye Water, visible from the above footpath


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2135 39 Rev B


The SWO 15 does not meet the DOEHLG requirements in terms of ‘Formula A’ and activation level.

This overflow is however considered as a short-term interim solution, until upgrade of foul sewer pipe at

Rye Bridge, downstream of SWO 15.

It is recommended to carry out flow monitoring of the foul sewer network on Pound Street, to enable

calibration of a hydraulic model to ascertain the required size of sewer to transverse the Rye Water

river at Rye Bridge.

The long Term strategy should however be to endeavour to eliminate extensive surface water ingress

into the foul network. This would have the beneficial impact of increasing the capacity of the foul

network for sewerage loads in Pound Street and Main Street area. This will also indirectly improve the

efficiency and cost effectiveness of Leixlip Waste Water Treatment Plant. To ensure there is no repeat

occurrence of flooding incidents through foul sewer network, it is also recommended to carry out a

complex study of the foul network upstream of Leixlip Town centre, to identify and remove incorrect

surface water connections.


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2135 40 Rev B

APPENDIX 1

DRAWINGS


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Pumping Station Pump Arrangement

Standby Generator

Avaiable Yes / No

Storage Capacity (m^3)

No of Emergency Overflows in 2012

Emergency Oveflow

Discharge Point

Kilcock Duty / Assist / Standby Yes 450 0 SW3

Maynooth Duty / Assist / Standby Yes 2850 4 SW4

Castletown Duty / Assist / Standby Yes 732 0 SW6

Primrose Hill Duty / Standby Yes 289 0 SW9

Ballyoulster Duty / Standby Yes 0 0 SW10

Temple Mills, Abbey Farm

Duty / Standby Yes 0 0 SW12

Straffan Duty / Standby Yes 100 0 SW14

Attachment C.1.2 Pumping Stations


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Reference Location Easting Northing Type Design Criteria Construction Detail Invert Level

SW1-P St Catherines Park, Leixlip 301633 235839 PrimaryOpen pipe -

constant discharge

Open pipe - 900mm concrete varies from

complete submergence to completely above

river level

Not Available

SW2 St Catherines Park, Leixlip 301546 235839 SWOOverflows when the associated

storm tank is full

Open pipe - 700mm concrete, completely

submerged at all times

Not Available

SW3 Kilcock Pumping Station 289638 239169 SWO

Overflows when pump sump and

storm water storage tank at pumping station

are full

375mm concrete pipe with flap valve, above

groundNot Available

SW4Fisheries Grounds, Old Dunboyne

Road, Maynooth294412 238713 SWO

Overflows when storm water

holding tank at pumping station

is full

450mm open concrete above river

levelNot Available

SW5 Maynooth Castle, Maynooth 293649 237671 SWO

Overflow operates if flow

exceeds the maximum

capacity of the downstream

pipeline

225mm ductile iron open pipe, above

water levelNot Available

Attachement C2 Outfall Design & Construction

Attachment C2 Lower Liffey Valley Regional Sewerage Scheme

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SW6Celbridge Main Pumping Station,

Castletown, Celbridge297981 233615 SWO

Overflows when storm water

holding tank at pumping station

is full

300mm ductile iron open pipe, above


SW7Castletown Gate Slip, Castletown,

Celbridge297585 233309 SWO


exceeds the maximum


pipeline

300mm open concrete pipe, above


SW8Castletown Gate Slip, Castletown,



exceeds the maximum


pipeline

450mm open concrete above river

levelNot Available

SW9 Newtown Road, Celbridge 297379 232911 SWO

Overflows when sewer backs up when pumping or storm water

holding capacity is exhausted

300mm open concrete pipe, above


SW10Ballyoulster Pumping Station,


Overflows when pump sump is

full

225mm open pvc pipe, above water

levelNot Available


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SW11Ballyoulster Pumping Station,


Overflows if there is a

blockage at the inflow to the

pump sump and the network is

surcharged

150mm open pvc pipe, above water

levelNot Available

SW12Temple Mills Pumping Station, Abbey

Farm, Celbridge296936 232433 SWO

Overflow when capacity of

pump sump is exhausted

300mm ductile iron pipe with flap valve, above water level

Not Available

SW13 Mill Lane, Leixlip 301155 235871 SWO

Overflow when sewer backs up

as a result of insufficient capacity

225mm concrete pipe with flap valve, above


SW14Straffan Pumping Station, Lodgepark,

Straffan292834 229614 SWO

Overflow when capacity of storm water

storage tank at the pumping

station is exhausted

300mm ductile iron pipe with flap valve, above water level

Not Available

SW15 Pound Street, Leixlip 300413 235863 SWO

Overflow when sewer backs up

as a result of insufficient capacity

Above water level stone storm culvert

Not Available

SWP-PE St. Catherine's Park, Leixlip 301653 235836 EOOverflow if the downstream

sewer is blocked

900mm concrete pipe, below water

levelNot Available


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Suspended Solids (mg/l)

COD (mg/l)

BOD (mg/l)

Total Nitrogen (mg/l N)

Total Phosphorous

(mg/l P)


COD (mg/l)

BOD (mg/l)

Total Nitrogen

(mg/l)

Total Phosphorous

(mg/l P)04/01/2012 398 736 nd 57 11.6 342 579 nd 39 7.311/01/2012 110 343 141 52 4 178 410 170 43 5.712/01/2012 242 583 290 70 4.1 138 334 183 41 2.418/01/2012 100 511 nd 74 5 178 394 nd 53 4.425/01/2012 118 316 nd 55 5.3 160 404 nd 46 401/02/2012 158 263 89 36 3.4 76 164 54 34 2.908/02/2012 92 246 nd 42 4.4 100 205 nd 23 3.709/02/2012 358 603 198 67 7 179 300 148 31 3.715/02/2012 68 227 126 43 4.9 276 384 234 45 6.322/02/2012 nd 289 nd 51 4.1 nd 136 nd 33 2.229/02/2012 220 676 nd 49 10.6 250 125 nd 18 408/03/2012 291 624 160 66 6.8 161 254 95 35 2.914/03/2012 422 659 225 70 9.8 244 409 154 52 3.621/03/2012 78 234 nd 40 4.7 70 124 nd 32 4.728/03/2012 294 607 171 42 8.2 62 151 68 35 304/04/2012 118 290 nd 48 6.6 78 185 nd 36 305/04/2012 430 731 290 66 5.5 228 445 150 44 3.611/04/2012 94 307 105 56 6.1 276 609 176 52 8.618/04/2012 112 314 95 58 6.1 248 447 155 65 6.925/04/2012 396 603 nd nd 10.7 296 560 nd nd 5.802/05/2012 264 367 111 40 6.1 50 110 24 24 1.803/05/2012 147 231 88 37 1.9 101 126 52 33 1.609/05/2012 76 196 nd 38 5 144 266 nd 33 3.916/05/2012 112 316 101 45 5.5 152 396 115 39 5.830/05/2012 236 527 nd 56 7.7 326 284 nd 33 9.231/05/2012 538 926 200 98 7.3 181 256 90 40 2.206/06/2012 68 197 84 39 4.4 318 409 198 43 9.320/06/2012 622 798 nd nd 11.7 206 321 nd nd 5.928/06/2012 434 516 100 76 5.9 41 95 34 34 1.6nd - not determined

Attachment D.1 - Influent Monitoring DataMain Plant Influent Data Intel Plant Influent Data

Date

Attachment D1 Lower Liffey Valley Regional Sewerage Scheme

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COD (mg/l)

BOD (mg/l)


Total Phosphorous

(mg/l P)


COD (mg/l)

BOD (mg/l)

Total Nitrogen

(mg/l)

Total Phosphorous

(mg/l P)11/07/2012 nd 798 nd nd 11.7 nd 321 nd nd 5.918/07/2012 354 671 188 62 7.9 184 290 120 24 3.625/07/2012 706 1215 nd 80 14.8 60 106 nd 30 2.726/07/2012 192 502 260 63 2.6 49 160 105 25 1.101/08/2012 68 252 nd 59 4.1 150 196 nd 43 3.508/08/2012 nd 486 nd 52 9.9 nd 262 nd 33 3.815/08/2012 698 2229 914 100 14.7 364 716 242 52 822/08/2012 170 1013 574 96 4.9 62 330 169 nd 2.723/08/2012 324 1044 380 77 3 172 490 168 41 1.729/08/2012 386 634 nd 60 7.9 92 155 nd 31 3.805/09/2012 376 684 284 63 9.5 218 394 167 32 5.512/09/2012 118 296 128 44 5.6 230 464 196 50 7.520/09/2012 104 307 118 52 3.1 89 188 50 31 2.126/09/2012 72 311 167 31 2.9 198 246 92 43 4.103/10/2012 nd 378 nd 51 4.1 nd 285 nd 34 2.610/10/2012 76 654 272 64 6.5 102 477 180 32 4.417/10/2012 90 421 nd 51 4.5 28 289 nd 34 2.218/10/2012 53 191 70 31 1.4 52 206 62 29 124/10/2012 nd 932 594 98 3.7 nd 440 226 39 2.821/10/2012 108 274 nd 39 nd 86 133 nd 24 6.507/11/2012 360 691 385 45 10.1 194 335 116 30 5.314/11/2012 94 242 nd nd 4.7 116 272 nd nd 4.315/11/2012 102 330 80 43 0.5 128 274 49 34 0.521/11/2012 nd 408 nd 46 5.7 nd 374 nd 71 528/11/2012 64 220 107 30 3.5 132 124 105 23 3.205/12/2012 470 802 225 63 9.1 188 309 130 31 3.912/12/2012 126 693 238 59 9.2 74 310 148 32 5.313/12/2012 93 421 155 52 3.1 258 588 235 49 419/12/2012 270 308 nd 44 4 244 463 nd 32 5.6nd - not determined

Main Plant Influent Data Intel Plant Influent Data

Date

Attachment D1 Lower Liffey Valley Regional Sewerage Scheme

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Attachment E2 Programme for Environmental Monitoring 1. Introduction The Sampling Plan for Leixlip Waste Water Treatment Plant is prepared to satisfy the monitoring requirements of WWDL Register Number D0004-01. This Plan indicates the minimum number of samples required to be taken, the type of samplers used and how samples should be taken. The samples are followed from point of sampling through to reporting. 2. Sampling Schedule 2(a) Influents Condition 4.16 of the WWDL sets out the minimum monthly influent monitoring. Table 1 Leixlip WWTP Influent Monitoring Plan

Parameter Influents Min No of Samples

BOD Yes 24 COD Yes 24 TSS Yes 24 Total P Yes 24 Total N Yes 24 2(b) Effluents Monitoring of the effluent at SW1 is performed as required by Schedule B.1 “Monitoring of Primary Waste Water Discharge” of the WWDL. Table 2 Leixlip WWTP Effluent Monitoring Plan

Parameter Monitoring Frequency

Analysis Method/Technique

Flow Continuous On-line flow meter with recorder

pH Weekly pH electrode/meter and recorder

BOD Fortnightly Standard Method COD Fortnightly Standard Method Suspended Solids Fortnightly Standard Method T Nitrogen Fortnightly Standard Method Nitrate (as N) Fortnightly Standard Method Nitrite (as N) Fortnightly Standard Method Oxidised Nitrogen (as N)

Fortnightly Standard Method

Attachment E2 Lower Liffey Valley Regional Sewerage Scheme

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Ammonia (as N) Fortnightly Standard Method Total Phosphorus (as P)


Orthophosphate (as P)


Fluoride Fortnightly Standard Method Oils, Fats & Greases

Quarterly Standard Method

Mercury & its compounds

Quarterly Standard Method

Metals & Organic Compounds

Biannually Standard Method

Toxicity Annual As agreed by the EPA Visual Inspection Daily Sample & examine

for colour 2(c) River Water Sampling Receiving water monitoring is performed so as to comply with Schedule B.4 “Ambient Monitoring” of the WWDL. Upstream sampling point (designation – aSW1-Pu) E301537 N235828, upstream of the SWO, designation SW2. Downstream sampling point (designation – aSW1-Pd) E302295 N235179, just downstream of the weir in Lucan and therefore after the mixing zone. Table 3 Receiving Water Monitoring

Parameter Monitoring Frequency

Analysis Method/Technique

pH Ten samples/year pH electrode/meter BOD Ten samples/year Standard Method Orthophosphate (as P)

Ten samples/year Standard Method

Total Nitrogen (as N)


Ammonia Ten samples/year Standard Method Fluoride Ten samples/year Standard Method Mercury & its Compounds


Metals & Organic Compounds

Annually Standard Method

Visual Inspection Weekly Sample & examine for colour


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3. Requirements for Sampling The use of composite samplers is essential to comply with Schedule B of the WWDL. A refrigerated flow proportional sampler is provided for the final combined effluent at SW1. This sampler has a six month service interval. Two refrigerated time proportional samplers are provided and used for influent samples – these samplers have a yearly service interval. Risk Assessment 30, Safety Manual, must be consulted prior to river sampling. River sampling locations are chosen based on validity of sample and safe access from the riverbank. The sampling location can not be altered with the agreement of the EPA. 4. Sampling Procedure 4(a) Introduction The objective of sampling is to collect a portion of material small enough in volume to be transported conveniently and handled in the laboratory while still accurately representing the material being sampled. This implies that the relative proportions or concentrations of all pertinent components will be the same in the samples as in the material being sampled, and that the sample will be handled in such a way that no significant changes in composition occur before the tests are made.

4(b) Sampling Procedure Consult the Leixlip WWTP Laboratory Methods Manuals to determine whether any special precautions should be taken when sampling for specific parameters. Therefore each point made below is for general samples, the Methods Manuals may require you to ignore certain points i.e. glass bottles used instead of plastic containers. The use of automatic samplers is essential, except in the case of surface water

samples. Samples are taken in plastic containers (1L or 2.5L). Containers are filled to the top to eliminate air/oxygen. When sampling, ensure that the material/sample is a homogenous mixture.

Samples from a composite sampler will need mixing before sampling. Samples must be transported to the laboratory in a cooler box. All samples must be labelled, indicating name of collector, date and time of

collection, place of collection. When sample is presented to the laboratory for analysis the sample is assigned a

number and sample details are logged in the laboratory logbook.


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5. Analysis Methods As a minimum, the minimum number of samples, as set out in Schedule B.1 and B.4 of the WWDL, shall be analysed by a laboratory which satisfies Condition 4.1 and 4.2 of the WWDL. 6. Quality Control Reference should be made to the Leixlip WWTP Laboratory Methods Manual for all details pertaining to Quality Control protocol in the Leixlip WWTP Laboratory. 7. Result Recording/Reporting Procedures All samples entering Leixlip WWTP Laboratory are logged in the Sample

Logbook. This allocates a unique identifying number to the sample. Parameters have an associated result logbook in which the sample details and

results are recorded. Results for all the parameters are recorded on the appropriate result sheet. Written copy of results to be provided to Plant Manager and Plant Supervisor on a

daily basis. All results are inputted into Lab Works and the Performance Management System,

from which a printout of results should be made available as soon as practicable. 8. Laboratory Accreditation The Leixlip WWTP Laboratory is not an accredited laboratory but does participate in the EPA Intercalibration Scheme.


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Date pHSuspended

Solids (mg/l)

COD (mg/l)

BOD (mg/l)


Total Phosphorous

(mg/l P)

Ammonia (mg/l N)

Orthophosphate (mg/l P)

Nitrate (mg/l N)

Nitrite (mg/l

N)

Fluoride (mg/l)

Oils, Fats &

Greases (mg/l)

Mercury (ug/l)

Fluoride (kg/day)

04/01/2012 7.0 5 18 15.9 0.4 1.2 0.35 15.6 0.259 1.5 5005/01/2012 7.2 <5 211/01/2012 7.2 5 29 1.1 22.1 0.5 3.75 0.38 20.1 0.325 1.72 5512/01/2012 7.2 6 24 3 22.4 0.3 2.96 0.25 18.12 0.896 1.69 0.255 5116/01/2012 7.2 <5 <218/01/2012 7.4 7 39 23 0.5 11 0.3 13 0.261 1.96 5625/01/2012 7.2 5 38 28.2 0.4 11.1 0.21 20.2 0.383 1.85 4 5526/01/2012 7.5 7 <10 <2 35 0.3 17 0.1 17 0.4 2 6730/01/2012 7.3 <5 <201/02/2012 7.2 6 29 1.7 19.1 0.31 0.79 0.26 19.4 0.573 1.34 4908/02/2012 7.2 7 23 22.5 0.3 3.13 0.2 22.8 0.891 1.36 4009/02/2012 7.1 11 23 <2 23.91 0.302 0.99 0.148 21.42 1.37 1.49 <0.04 4113/02/2012 7.1 6 <215/02/2012 6.9 6 14 1.2 24.7 0.44 1.6 0.24 26.7 0.345 1.77 4822/02/2012 7.4 6 29 24.5 0.27 2.14 0.21 23.1 0.22 1.68 4523/02/2012 7.2 5 26 3 30 0.18 1.14 0.13 26 0.23 1.46 4027/02/2012 7.3 7 <229/02/2012 7.2 5 19 25.9 0.31 0.61 0.24 29.5 0.091 1.96 5206/03/2012 6.207/03/2012 7.4 7 31 0.32 16.53 7.7 0.10408/03/2012 7.5 13 32 <2 27.1 0.346 17.55 0.094 7.46 0.599 1.72 <0.0309/03/2012 3.5713/03/2012 7.6 <5 <214/03/2012 7.3 5 28 1 27.5 0.28 3.63 0.17 25.8 0.067 2.02 5021/03/2012 7.2 4 15 1.5 19.6 0.369 0.24 0.21 23.1 0.028 1.68 4522/03/2012 7.1 <5 22 2 30 0.24 0.61 <0.16 29.45 0.05 1.72 1 4526/03/2012 7.3 <5 <228/03/2012 7.1 6 40 1 30.6 0.47 3.02 0.33 29.1 0.075 2.03 5104/04/2012 7.2 6 34 23.2 0.39 0.34 0.25 32.8 0.022 1.9 46

Attachment E.4a Final Effluent Sampling @ SW1

Where no result is provided the parameter was not determined on that date

Attachment E.4a Lower Liffey Valley Regional Sewerage Scheme

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Date pHSuspended

Solids (mg/l)

COD (mg/l)

BOD (mg/l)


Total Phosphorous

(mg/l P)

Ammonia (mg/l N)


Nitrate (mg/l N)

Nitrite (mg/l

N)

Fluoride (mg/l)

Oils, Fats &

Greases (mg/l)

Mercury (ug/l)

Fluoride (kg/day)

05/04/2012 7.2 11 27 <2 31.6 0.38 0.03 0.153 30.4 0.034 3.4 <0.03 8309/04/2012 7.3 <5 <211/04/2012 7.0 5 36 1 23.7 0.38 0.38 0.24 24.3 0.022 1.8 4718/04/2012 7.4 12 33 2.4 27.2 0.74 0.77 0.49 29.3 0.135 2 5519/04/2012 7.2 <5 21 <2 31 0.46 0.48 <0.16 29.6 0.13 1.3 3923/04/2012 7.3 <5 <225/04/2012 7.2 8 15 0.36 0.68 0.24 26 0.07 1.8 4502/05/2012 7.4 5 30 1 18.5 0.28 0.26 0.21 21.6 0.073 1.25 5303/05/2012 7.3 15 19 <2 24.85 0.228 0.06 0.104 22.56 0.052 0.84 <0.03 3508/05/2012 7.6 <5 <209/05/2012 7.3 6 22 16.3 0.25 0.14 0.18 20.4 0.025 1.46 4516/05/2012 7.0 5 17 0.9 27.1 0.27 0.31 0.23 30.7 0.129 1.12 3017/05/2012 7.4 <5 22 <2 30 0.21 0.04 <0.16 30.7 <0.03 1.18 4 3221/05/2012 7.5 6 <230/05/2012 7.4 6 18 25.3 0.21 0.21 0.11 23.8 0.026 1.74 4431/05/2012 7.1 9 21 <2 28.8 0.165 0.37 0.098 27.63 0.039 1.19 <0.03 3005/06/2012 7.5 <5 <206/06/2012 7.2 4 12 1 18 0.19 0.23 0.11 19.2 0.026 1.74 4814/06/2012 7.2 <5 24 3 29 <0.05 2.7 <0.16 24 0.1 1.3 2.7 3718/06/2012 7.2 <5 <220/06/2012 7.2 6 23 1 0.23 1.07 0.11 21 0.064 1.43 3928/06/2012 7.4 15 25 <2 30.15 0.217 5.19 0.17 23.82 0.169 1.5 <0.03 5202/07/2012 7.2 <5 <211/07/2012 7.0 19 25.7 0.25 1.43 0.1 23.6 0.097 1.12 3813/07/2012 7.2 7 11 2 29 0.09 3 <0.16 28 0.03 1.1 5 3416/07/2012 7.1 5 <218/07/2012 7.0 5 15 1.3 16.9 0.25 0.3 0.09 18.2 0.031 1.94 6925/07/2012 7.3 2 25 22 0.29 1.94 0.24 19.6 0.107 1.4 4726/07/2012 7.1 12 12 <2 18.25 0.182 1.19 0.105 12.02 0.625 0.83 <0.03 30

Where no result is provided the parameter was not monitored on that date


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EPA Export 25-04-2013:23:32:14

Date pHSuspended

Solids (mg/l)

COD (mg/l)

BOD (mg/l)


Total Phosphorous

(mg/l P)

Ammonia (mg/l N)


Nitrate (mg/l N)

Nitrite (mg/l

N)

Fluoride (mg/l)

Oils, Fats &

Greases (mg/l)

Mercury (ug/l)

Fluoride (kg/day)

01/08/2012 7.4 5 24 16.2 0.2 1.92 0.09 13.5 0.113 2.03 6108/08/2012 7.4 15 20.4 0.23 0.17 0.1 22.9 0.045 1.43 3610/08/2012 7.4 <5 26 <2 21 0.22 0.3 0.16 24 0.03 1.6 4113/08/2012 7.5 <5 <215/08/2012 7.5 4 35 1 18.9 0.24 2.45 0.2 16.7 0.278 1.73 4322/08/2012 7.4 5 19 1.4 8 0.19 1.42 0.15 4.5 0.498 1.79 4923/08/2012 7.1 2 8 <2 6.88 0.115 0.29 0.066 5.69 0.1 1.51 <0.03 3727/08/2012 7.3 <5 <229/08/2012 7.1 4 21 12.2 0.31 0.79 0.14 12.1 0.197 1.8 5905/09/2012 7.1 6 25 1.2 17.6 0.31 1.21 0.24 19.1 1.91 4706/09/2012 7.5 <5 10 2 19 0.2 3.9 0.15 2.4 0.2 1.6 2 3911/09/2012 7.0 <5 <212/09/2012 7.0 3 20 1.6 19.3 0.3 2.95 0.12 19.9 0.254 1.8 4320/09/2012 7.2 11 17 <2 19.4 0.26 0.65 0.096 19.28 0.121 0.68 <0.03 1624/09/2012 7.2 <5 <226/09/2012 7.4 5 20 1.5 12.5 0.18 1.65 0.14 11.8 0.09 1.04 4203/10/2012 23 15.2 0.21 1.67 16.2 0.145 1.39 4004/10/2012 7.5 <5 21 3 20 0.16 2.8 <0.16 13 0.03 1.2 4 3409/10/2012 7.2 6 <210/10/2012 7.2 4 25 1.2 17.8 0.21 0.64 0.09 20.6 0.07 1.31 3517/10/2012 7.5 6 35 15.2 0.27 11.89 0.13 6.3 0.111 1.28 4518/10/2012 7.5 11 31 <2 16.17 0.142 7.27 0.055 6.38 0.265 0.99 <0.03 4217/10/2012 1.4122/10/2012 7.4 <5 <224/10/2012 7.5 6 32 1.7 17.7 0.24 5.41 0.14 13.8 0.141 1.28 3631/10/2012 7.2 4 13 1 17.1 0.28 0.12 0.13 20.7 0.015 1.47 3701/11/2012 7.8 <5 14 <2 24 0.22 0.04 0.12 22 <0.03 1 4 2705/11/2012 7.1 <5 <207/11/2012 7.2 3 24 1 18.9 0.26 1.08 0.14 20.914/11/2012 7.4 5 20 0.28 1.45 0.14 20.6 0.164 1.64 46



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EPA Export 25-04-2013:23:32:14

Date pHSuspended

Solids (mg/l)

COD (mg/l)

BOD (mg/l)


Total Phosphorous

(mg/l P)

Ammonia (mg/l N)


Nitrate (mg/l N)

Nitrite (mg/l

N)

Fluoride (mg/l)

Oils, Fats &

Greases (mg/l)

Mercury (ug/l)

Fluoride (kg/day)

15/11/2012 7.1 6 15 <2 19.7 0.152 0.62 0.129 18.47 0.107 0.61 <0.04 1720/11/2012 7.0 <5 221/11/2012 7.4 28 20.6 0.31 2.32 0.21 20.8 0.182 1.54 4328/11/2012 7.6 6 18 1.6 13.5 0.2 0.24 0.12 11.6 0.041 0.84 3229/11/2012 7.4 7 31 <2 14 0.05 0.06 <0.16 12 <0.03 0.97 3203/12/2012 7.2 <5 <205/12/2012 7.4 6 27 0.7 20.7 0.17 0.71 0.09 19.6 0.111 1.22 3812/12/2012 7.3 7 18 1.4 23.1 0.22 0.49 0.09 21.8 0.165 1.07 3113/12/2012 7.1 10 34 2 21.26 0.312 0.41 0.05 19.9 0.241 0.1 <0.04 317/12/2012 7.2 <5 2519/12/2012 7.5 6 21 19.3 0.23 0.15 0.09 23 0.051 1.11 3127/12/2012 7.4 9 14 <2 12.4 0.226 0.16 0.076 11.12 0.116 1.09 <0.03 33



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EPA Export 25-04-2013:23:32:14

DateArsenic

(ug/l)Atrazine

(ug/l)Chromium

(ug/l)Copper (ug/l)

Cyanide (ug/l)

Dichloromethane

(ug/l)

Lead (ug/l)

Nickel (ug/l)

Simazine (ug/l)

Toulene (ug/l)

Tributyltin (ug/l)

Xylene (ug/l)

Zinc (ug/l)

09/02/2012 0.445 <0.01 <0.28 <0.51 <5 <5.00 <0.12 2.541 <0.01 <0.54 <0.02 <0.73 7.36826/07/2012 0.225 <0.01 1.744 6.696 <5 <5.00 0.276 5.09 <0.01 <0.54 <0.02 <0.73 12.4413/12/2012 <0.18 <0.01 0.614 7.834 <5 <5.00 <0.12 5.537 <0.01 <0.54 <0.02 <0.73 20.63

DateBarium (ug/l)

Boron (ug/l)

Cadmium (ug/l)

Conductivity uscm

@20deg

DO (mg/l)

Hardness (mg/l

CaCO3)

Total Phenols

(ug/l)

Selenium(ug/l)

Sulphate (mg/l)

13/12/2012 11.24 91.47 <0.05 823 5.8 262 <0.10 <2.12 186.85


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Attachment E.4b Compliance with monitoring requirements and treatment standards Table E.4b(i) – Compliance with Monitoring Requirements & Treatment Standards as required by the WWDL (D0004-01)

pH

BOD (mg/l)

COD mg/lTSS

(mg/l) Ammonia (mg/l N)

Nitrate (mg/l N)

Nitrite (mg/l N)

Total P (mg/l)


Fluoride (kg/d)

OFG's (mg/l)

WWDL ELV6.0-9.0

8 100 15 2.75 14.9 1 0.5 0.39 180 15

ELV with Condition 2

interpre. Included

6.0-9.0

16 200 37.5 3.3 17.9 1.2 0.6 0.47 180 18

Number of sample results

96 75 73 93 75 72 70 72 70 69 8

Number of samples

above WWDL ELV

0 0 0 0 16 55 1 1 1 0 0

Number of samples

above ELV with

Condition 2 interpretation included

0 0 0 0 10 51 1 1 1 0 0

Overall compliance

Pass Pass Pass Pass Fail Fail Fail Fail Fail Pass Pass

Attachment E.4b Lower Liffey Valley Regional Sewerage Scheme

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Table E.4b(ii) – Compliance with Monitoring Requirements & Treatment Standards as required by the UWWT Regs

Parameter UWWT Regs Limit

Frequency / annum

required

Actual Number of Samples in

2012

Maximum Result in

2012

Overall Compliance

BOD (mg/l) 25 24 >24 3 Pass

COD (mg/l) 125 24 >24 40 Pass

TSS (mg/l) 35 24 >24 15 Pass

Total Phosphorous

(mg/l P) 2 24 >24 0.74 Pass

Attachment E.4b Lower Liffey Valley Regional Sewerage Scheme

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Attachment F.1 Assessment of Impact on Receiving Surface or Ground Water

a) Existing Environment (a)1. Biological Water Quality In 2012 BEC Consultants Ltd carried out biological water quality monitoring for Kildare County Council upstream and downstream of SW1. A field survey was carried out on August 10th at three sites on the River Liffey, one downstream (D1) and two upstream (U1 and U2) of the discharge. Site D1 was located downstream of the Lucan weir located off the N4 motorway between Leixlip and Lucan. The sampling site was as close as practical to aSW1d, safe access and river bed conditions had to be considered. Site U1 was located directly upstream of the bridge in Leixlip, aSW1u was not suitable so the sampling site was moved upstream. Site U2 was located directly upstream of the bridge in Celbridge.

Table 1. Details of the survey sites.

Site code Irish Grid (10m

accuracy) Description

U2 29736 23291 Upstream of bridge in Celbridge U1 30080 23583 Upstream of bridge in Leixlip D1 30223 23528 Downstream of Lucan Weir

Biological water quality, as indicated by Q-values was the same at all three sites Q3, indicating moderately polluted, Class C water. This indicates a reduction in the water quality at Celbridge (U2) of the River Liffey when compared to the EPA data from the 2010 sampling period (EPA, 2012), which rated water quality at Celbridge as Q4, Leixlip as Q3 and downstream of Leixlip as Q3. Both Leixlip (U1) and downstream of Leixlip (Q3) remain the same. When compared with the survey carried by EcoServe in 2011, on behalf of Kildare County Council, it indicates that the water quality has deteriorated at U2 (was Q4 now Q3), and D1 (was Q3-4, now Q3) and stayed the same at U1 (Q3). The fact that water quality appears to have deteriorated at all three sample sites suggests the deterioration is linked to a wider catchment effect, possible related to the high levels of rainfall that occurred over the summer of 2012. (a)2. Physico-chemical conditions The following description of the existing environment is based on 2012 ambient monitoring submitted electronically as required in the Section F of this application. The pH upstream and downstream of SW1 was at all times compliant with the EQS for hard water – 6.0 <pH<9.0.

Attachment F.1 Lower Liffey Valley Regional Sewerage Scheme

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BOD was compliant upstream and downstream with the required 95%ile High Status limit of <2.2mg/l. Upstream of SW1 the total ammonia was compliant with the Good Status <0.140mg/l N 95%ile. However the 95%ile downstream was >0.140mg/l N and therefore can not be classified as being of Good Status. Orthophosphate does not comply with EQS for Good Status 95%ile for MRP of <0.075mg/l P either upstream or downstream of SW1. Mercury, fluoride, arsenic, atrazine, chromium, copper, cyanide, dichloromethane, lead, nickel, simazine, toluene, xylenes, zinc, cadmium and total phenols all comply upstream and downstream with their EQS’s. Tributlytin was at all times below its limit of detection, 0.02 ug/l, upstream and downstream of SW1 and therefore no further comment can be made on its compliance with its EQS. There is no EQS for Total Oxidised Nitrogen (TON) but the Water Quality Management Plan (WQMP) for the Liffey Catchment set a 95%ile of 5mg/l N - upstream and downstream of SW1 complied with this limit. As per TON there is no EQS for suspended solids, barium, boron, selenium and sulphate but the all complied, upstream and downstream of SW1 with the WQMP for the Liffey Catchment. (a)3. Designations of Receiving Water Body The receiving water body for the Leixlip WWTP primary discharge (SW1) is the River Liffey. The River Liffey has no Natura 2000 designation at the primary discharge point. However, the River Liffey discharges to the South Dublin Bay and River Tolka Special Protection Area approximately 23km downstream of SW1. The River Liffey is designated as sensitive to phosphorous under the Urban Wastewater Treatment Regulations upstream and downstream of the primary discharge point. The River Basin Management Plan for the River Liffey classifies the receiving water at the discharge point as being of Moderate Quality with Good Status to be achieved by 2021. (a)4. Downstream Abstractions and Uses of Water There are no drinking water abstractions downstream of the Leixlip Waste Water Treatment Plant. There are no designated bathing waters in the River Liffey downstream of Leixlip Waste Water Treatment Plant. There are designated bathing waters in the Dublin Bay area. Due too the distance and high level of dilution and dispersion of discharges from


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the Leixlip Waste Water Treatment Plant, prior to potentially reaching any bathing water, any impact is negligible. The OPW in conjunction with local authorities in Kildare, Fingal, South Dublin and Dublin City prepared a Strategy Report for the Liffey Valley Park. The report reviewed the recreational, access, ecological and built heritage resources along the River Liffey from Ballymore Eustace to Islandbridge. The report identifies canoeing and rowing as the main uses of the River Liffey downstream of the Leixlip Waste Water Treatment Plant. (a)5. Ground Emissions from the Waste Water Treatment Plant There are no discharges to groundwater from Leixlip Waste Water Treatment Plant. (a)6. Flow Data Table 2. River Liffey and Rye Water Flow Data Monitoring Site

Easting Northing DWF (m3/sec) 95%ile (m3/sec)

River Liffey @ Powerstation, Leixlip

300600 235800 2.0 2.0

Rye Water @ Leixlip

300523 236434 0.05 0.09

Leixlip WWTP SW1

301633 235839 2.05 2.09

(a)7. Volumetric Contribution by Site Flow Table 3. Levels of Dilutions Available Leixlip WWTP

WWTP DWF (m3/sec)

Total DWF @ SW1 (effluent + river)

Level of Dilution

Effluent DWF % of River DWF

150,000 pe

0.561 2.61 1 in 4.7 22


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b) Predicted Impact of the 150,000 pe WWTP on the River Liffey Table 4. Impact on the River Liffey of the 150,000 pe plant based on existing receiving water

Parameter River Liffey Flow

(m3/sec)

Upstream @ aSW1u

WWTP DWF

(m3/sec)

Max Daily average @ SW1

Downstream Predicted

BOD (mg/l) 2.09 <2 0.561 6^* #VALUE! COD (mg/l) 2.09 8* 0.561 71^* 21.3400 TSS (mg/l) 2.09 12.7* 0.561 11^* 12.3449 Total N (mg/l N) 2.09 4.64 0.561 3.6595 Total P (mg/l P) 2.09 0.054* 0.561 0.36^* 0.1188 Total ammonia (mg/l N) 2.09 0.119* 0.561 0.62^* 0.2251 Orthophosphate (mg/l P) 10.7 0.035** 0.561 0.28^* 0.0472 Fluoride (mg/l) 2.05 0.17^ 0.561 3.7^*^ 0.9288 Sulphate (mg/l) 2.09 10.58^ 0.561 186.85^*^ 47.9000 Nitrate (mg/l N) 2.09 2.71* 0.561 10.6^* 4.3813 Nitrite (mg/l N) 2.09 0.034* 0.561 0.71^* 0.1771 Phenol (mg/l) 2.05 <lod 0.561 <0.10^*^ 0.0000 Atrazine (mg/l) 2.05 <lod 0.561 <0.01^*^ 0.0000 Dichloromethane (mg/l) 2.05 <lod 0.561 <5.00^*^ 0.0000 Simazine (mg/l) 2.05 <lod 0.561 <0.01^*^ 0.0000 Toulene (mg/l) 2.05 <lod 0.561 <0.54^*^ 0.0000 Tributylin (mg/l) 2.05 <lod 0.561 <0.02^*^ 0.0000 Xylene (mg/l) 2.05 <lod 0.561 <0.73^*^ 0.0000 Arsenic (mg/l) 2.05 0.0004^ 0.561 0.0004^*^ 0.0004 Chromium (mg/l) 2.05 0.0006^ 0.561 0.0074^*^ 0.0021 Copper (mg/l) 2.05 0.0025^ 0.561 0.0078^*^ 0.0036 Cyanide (mg/l) 2.05 <lod 0.561 <5^*^ 0.0000 Lead (mg/l) 2.05 0.0003^ 0.561 0.0003^*^ 0.0003 Nickel (mg/l) 2.05 0.0014^ 0.561 0.0055^*^ 0.0023 Zinc (mg/l) 2.05 0.0032^ 0.561 0.0206^*^ 0.0069 Boron (mg/l) 2.05 <lod 0.561 91.47^*^ 0.0000 Cadmium (mg/l) 2.05 <lod 0.561 <0.05^*^ 0.0000 Mercury (mg/l) 2.05 0 0.561 0.00026^*

^ 0.00005

Selenium (mg/l) 2.05 <lod 0.561 <2.12^*^ 0.0000 Barium (mg/l) 2.05 0.0222^ 0.561 0.0011^*^ 0.0177

*95%ile from 2012 monitoring **median from 2012 monitoring as required in Section G.2 of the Application Guidance Notes ^average from 2012 monitoring <lod – below limit of detection ^*design ^*^max from 2012 monitoring

The maximum level discharged at SW1 in 2012 was less than the EQS for inland surface waters for arsenic, atrazine, chromium, copper, cyanide, dichloromethane, lead, nickel, simazine, toluene, total xylene, zinc, cadmium and total phenols. Therefore the discharge from Leixlip Waste Water Treatment Plant can not impact on the EQS status for any of these substances.


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Mercury was on one occasion, 14 samples in total, detected in the final effluent at SW1. Mercury levels at aSW1u were at all times <0.03ug/l therefore, assuming no mercury in the receiving water, gives a predicted impact of 0.05ug/l Hg downstream at aSW1d – this complies with the AA-EQS and MAC-EQS. Fluoride has a predicted downstream level of 929ug/l. This is in excess of its EQS of 500ug/l. However as per the attached report “Report on Fluoride at Leixlip Waste Water Treatment Works and in the River Liffey” the quantity of measurable dissolved fluoride is considerably lower than the mathematically predicted value. The report attributes this to the high hardness level of the water and states that the fluoride has been progressively converted to a non-toxic non-biologically reversible form of fluoride (calcium fluoride) and therefore is of no environmental significance. It is highlighted that the calculation of the fluoride assimilative capacity in the River Liffey is not a straightforward one as the form of fluoride needs to be taken into account. This conclusion is supported by Kildare County Council monitoring – the maximum recorded downstream, since receipt of the WWDL, was 390ug/l on the 28th October 2009. Tributlytin was at all times below its limit of detection, 0.02ug/l, and therefore no further comment can be made on its predicted impact. There is no EQS for TON but the Water Quality Management Plan (WQMP) for the Liffey Catchment set a 95%ile of 5mg/l N – the predicted impact of 4.56mg/L N complies with this limit. As per TON there is no EQS for suspended solids, barium, boron, selenium and sulphate but the maximum daily average of all these parameters complied with the maximum river levels in the WQMP for the Liffey Catchment. 13 out of 14 results for BOD at aSW1u found <2mg/l. In order to predict the impact it is necessary to assume the 13 results found to be <2mg/l were 0.26mg/l (a notionally clean river) leaving the one remaining result at 3mg/l. The predicted impact at the design BOD of 6mg/l is therefore 2.2mg/l at aSW1d. 2.2mg/l complies with the High Status 95%ile limit. The impact on the receiving water of orthophosphate and ammonia calculates as non compliant with regard to their respective EQS’s. It is however inappropriate to impose too high standards on the discharge at SW1 because of the condition of the receiving water upstream of the Leixlip WWTP primary discharge point. Therefore it is appropriate in this case to take a notionally clean river approach. Using this approach orthophosphate will comply with the High Status EQS limit and total ammonia will comply with the Good Status 95%ile limit.


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Table 5. Impact on the River Liffey of the 150,000 pe plant based on a notionally clean river


(m3/sec)

Upstream @ aSW1u

WWTP DWF

(m3/sec)

Max Daily average @ SW1


BOD (mg/l) 2.09 1.2 0.561 6 2.2166 Orthophosphate (mg/l P) 10.7 0.005 0.561 0.28 0.0187 Total ammonia (mg/l N) 2.09 0.008 0.561 0.62 0.1376

c) Assimilative Capacity of the Receiving Water Table 6. Assimilative of the River Liffey based on the 150,000 pe WWTP


(m3/sec)

Upstream @ aSW1u

WWTP DWF

(m3/sec)

Max allowed in

River Liffey @ aSW1d

Maximum Allowed in Effluent @

SW1

WAC kg/day

BOD (mg/l) 2.09 <2 0.561 2.6 #VALUE! #VALUE! COD (mg/l)^* 2.09 8* 0.561 TSS (mg/l) 2.09 12.7* 0.561 25 70.82 3432.84 Total N (mg/l N)^*

2.09 4.64 0.561

Total P (mg/l P)^*

2.09 0.054* 0.561

Total ammonia (mg/l N)

2.09 0.119* 0.561 0.14 0.218 10.58


10.7 0.035** 0.561 0.035 0.035 1.70

Fluoride (mg/l) 2.05 0.17^ 0.561 0.5 1.71 82.68 Sulphate (mg/l) 2.09 10.58^ 0.561 200 905.68 43898.79 TON (mg/l) 2.09 2.744* 0.561 5 13.41 649.73 Phenol (mg/l) 2.05 <lod 0.561 0.008 0.0372 1.80 Atrazine (mg/l) 2.05 <lod 0.561 0.0006 0.0028 0.14 Dichloromethane (mg/l)

2.05 <lod 0.561 0.02 0.0931 4.51

Simazine (mg/l) 2.05 <lod 0.561 0.001 0.0047 0.23 Toulene (mg/l) 2.05 <lod 0.561 0.01 0.0465 2.26 Tributylin (mg/l) 2.05 <lod 0.561 0.0000002 0.0000 0.00 Xylene (mg/l) 2.05 <lod 0.561 0.01 0.0465 2.26 Arsenic (mg/l) 2.05 0.0004^ 0.561 0.025 0.1149 5.57 Chromium (mg/l) 2.05 0.0006^ 0.561 0.002 0.0071 0.34 Copper (mg/l) 2.05 0.0025^ 0.561 0.03 0.1305 6.32 Cyanide (mg/l) 2.05 <lod 0.561 0.01 0.0465 2.26 Lead (mg/l) 2.05 0.0003^ 0.561 0.0072 0.0324 1.57 Nickel (mg/l) 2.05 0.0014^ 0.561 0.02 0.0880 4.26 Zinc (mg/l) 2.05 0.0032^ 0.561 0.1 0.4537 21.99 Boron (mg/l) 2.05 <lod 0.561 2 9.3084 451.18 Cadmium (mg/l) 2.05 <lod 0.561 0.00008 0.0004 0.02 Mercury (mg/l) 2.05 0 0.561 0.00005 0.0002 0.01 Selenium (mg/l) 2.05 0.0024^ 0.561 0.01 0.0378 1.83 Barium (mg/l) 2.05 0.0222^ 0.561 1 4.5731 221.66


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*95%ile from 2012 monitoring **median from 2012 monitoring ^average from 2012 monitoring ^*no EQS or limit in WQMP Table 7. Assimilative Capacity of the River Liffey for the 150,000 pe plant based on a notionally clean river


(m3/sec)

Upstream @ aSW1u

WWTP DWF

(m3/sec)

Max allowed in

River Liffey @ aSW1d

Maximum Allowed in Effluent @

SW1

WAC kg/day

BOD (mg/l) 2.09 1.2 0.561 2.6 7.81 378.82 Total ammonia (mg/l N)

2.09 0.008 0.561 0.14 0.63 30.62


10.7 0.005 0.561 0.035 0.61 29.43

The emission limit values (ELV’s) set in the waste water discharge licence, D0004-01 May 2009, were set based on a daily flow of 34,560m3/day. The proposed flow has now been increased to 48,500m3/day to allow for an increase in the industrial flow rates. The final effluent concentrations based on an allowable effluent in terms of kg/day have consequently been reduced. The design limits used to assess the impact of the discharge in Tables 4 and 5 are 71.25% of the original ELV’s with no consideration for the assimilative capacity, this excludes the ammonia ELV which was based on the assimilative capacity and its EQS. The result being that some of the parameters proposed ELV’s are more onerous than they need be. Table 8. Impact on the River Liffey of the 150,000 pe plant when the proposed ELV’s in Table 4 and 5 are adjusted to reflect the available assimilative capacity or where appropriate “a notionally clean river”


(m3/sec)

Upstream @ aSW1u

WWTP DWF

(m3/sec)

Proposed ELV @ SW1


BOD (mg/l) 2.09 1.2 0.561 8 2.640 COD (mg/l) 2.09 8 0.561 100 27.479 TSS (mg/l) 2.09 12.7 0.561 15 13.192 Total ammonia (mg/l N) 2.09 0.008* 0.561 0.63 0.140 Orthophosphate (mg/l P) 10.7 0.005* 0.561 0.39 0.024 TON (mg/l N) 2.09 2.74 0.561 13.4 4.998

*a notionally clean river From Table 8 it can be seen that leaving the ELV’s for BOD and orthophosphate at the existing WWDL limits still allows for achieving Good Status at aSW1d. Suspended solids does not have an EQS but applying the WWDL ELV of 15mg/l results in aSW1d still being below the WQMP limit of 25mg/l.


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In order to achieve the TON WQMP limit of 5mg/l N the existing WWDL limit would have to be reduced from 15.9mg/l N to 13.4mg/l N but this is not as low as the more onerous than necessary proposed TON limit of 11.3mg/l N. Based on the assimilative calculations for this licence review the total ammonia proposed ELV should in fact be 0.63mg/l N.

d) Dangerous Substances Regulations S.I. No. 12 of 2001

Substances formally covered by the Dangerous Substances Regs. were discussed in Section b. Emissions of substances (defined in the Dangerous Substances Regs.) are not likely to impair the environment.

e) Appropriate Assessment Screening for an Appropriate Assessment was carried in 2012 and a report, Attachment B.6, was produced in June 2012. The conclusion of the assessment was that no significant impacts on Natura 2000 sites are predicted from the proposed works (alone or in combination with other projects or plans). Accordingly a Stage 2 Appropriate Assessment was deemed unnecessary.


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REPORT ON FLUORIDE AT LEIXLIP WWTW AND IN THE RIVER LIFFEY

Nicholas O'Dwyer Ltd.

June 2007


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EPA Export 25-04-2013:23:32:14

NICHOLAS O'DWYER LTD.

REPORT ON FLUORIDE AT LEIXLIP AND IN THE RIVER LIFFEY Nicholas O’Dwyer Ltd., Consulting Engineers, Nutgrove Office Park, Nutgrove Avenue, Dublin 14. August 2007

Prepared by Approved by Issued by PROJECT NO. 20406

Initials Date Initials Date Initials Date

Revision Reason for Revision PMN 15/8/07 ND 15/8/07 ND 15/8/07

A

B

C

D


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CONTENTS

1. INTRODUCTION 1

2. MASS BALANCE OF FLUORIDE THROUGH LEIXLIP WWTW 3

2.1 Total Influent and Effluent Fluoride Loads 3

2.2 Fluoride removal at the Wastewater Treatment Plant. 5

3. FLUORIDE ASSIMILATIVE CAPACITY OF THE RIVER LIFFEY 7

3.1 Survey Measurements carried out in the River Liffey 7

3.2 Fluoride Assimilative Capacity Calculation 11

4. CONCLUSIONS AND RECOMMENDATIONS 14


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1. INTRODUCTION

Nicholas O’Dwyer Consulting Engineers were appointed on the 26th of April 2007 for the

● Contract administration of a Fluoride Flow and Load survey

● To determine a Mass Balance for Fluoride across the Leixlip Waste Water

Treatment Plant

● To assess the effect, if any, of fluoride emissions to the River Liffey

● To detail all of the above in a single report

A flow and load survey for fluoride was carried out by Nutrisolv Ltd. between 22nd and

30th May 2007 upstream and downstream of the Wastewater Treatment Works (WWTW)

at Leixlip and also upstream and downstream of the WWTW discharge location to the

River Liffey. Samples and flows were measured on a 24-hour composite basis from the

Intel plant effluent line, on three sewage lines entering the WWTW and on the combined

effluent from the WWTW as detailed in Appendix A. Grab samples were taken from the

Liffey just upstream (600m approx) of the WWTW effluent discharge point and also at

Lucan bridge approx 2.5km downstream of the WWTW effluent discharge point, well

after the mixing zone for WWTW effluent. Flow in the Liffey was also monitored courtesy

of the ESB.

Leixlip WWTW is a treatment plant with two main Streams:

The Intel Stream consisting of:

2No Aeration basins with Anoxic Zones

2No Clarifiers

Tertiary filtration

The Main Plant Stream consisting of:

2No. Primary Settlement Tanks

2No Aeration Basins

3No. Clarifiers

The Dewatering Facilities consist of:

4No. Digesters & associated gas CHP unit.

3No. Picket Fence Thickeners

Centrifuge Dewatering Plant


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Under normal operation wastewater from the Intel Factory is mixed with some domestic

wastewater at the Intel Stream. This is done because the effluent from the Intel Plant

has a low organic load and it is necessary to increase the wastewater strength with

Domestic wastewater to ensure effective and efficient treatment of the Intel Stream at

the WWTW. The main plant stream treats domestic wastewater only.

This report is concerned with:

1. Mass Balance of Fluoride Through Leixlip WWTW

2. Determine the effect, if any of the fluoride discharges from the WWTW on the

River Liffey


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2. MASS BALANCE OF FLUORIDE THROUGH LEIXLIP WWTW

2.1 Total Influent and Effluent Fluoride Loads

Wastewater comes to Leixlip WWTW through three lines, a 750mm Intel Line bringing

effluent from the Intel Facility with a small number of houses from Leixlip included,

through a 750mm Domestic Line collecting Wastewater from Leixlip, Clane, Straffan,

Celbridge and Maynooth and through a 380mm Domestic Line collecting Domestic

wastewater from Leixlip. At the Leixlip WWTW Inlet works there are no locations suitable

for a flow and load survey due to the high levels of flow so it was necessary to find

sampling locations in the town close to the plant. These locations are approx. 400m

upstream of the inlet works on and around Mill Lane

Fluoride was measured on a flow-proportional 24-hour composite basis with

corresponding flows at the:

Outlet from the balance tank at the Intel Facility

At the 750mm Intel Line

At the 750mm Domestic Line

At the 380mm Domestic Line as detailed below:

750 Intel Line Sampling Location

750mm & 380mm Domestic Line Sampling Locations

Time-proportional only sampling was carried out at the combined effluent from the

treatment plant as for Health and Safety reasons it was not possible to mount a flow


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meter on the combined effluent line. This was due to the high levels of flow which made

the installation of any flow meter impossible.

Flow measurement in the 750 Intel Line closely agrees with the flow measurements

taken at the outlet from the balance tank at the Intel Facility as detailed in Appendix A

page 5. The discrepancies are due to the small number of domestic houses in Leixlip that

connect into the 750mm Intel Line.

The values sampled, tested and recorded for each of the three lines detailed above were

added together to give the total Fluoride load to Leixlip WWTW, the effluent samples

were also tested and recorded and then multiplied by the total measured influent flow to

calculate the effluent Fluoride load from Leixlip WWTW. The results are detailed in the

table below:

Date Total

Measured

Influent Flow

m3/day

Influent

Fluoride

Load

Kg/day

Effluent

Concentration

mg/l

Effluent

Fluoride

Load

Kg/day

Effluent

Suspended

Solids Load

Kg/day

22-23.05.07 23148 67.9 3.1 71.8 92.6

23-24.05.07 24701 66.1 4.2 103.7 444.6

24-25.05.07 23170 64.7 3.3 76.5 69.5

25-26.05.07 22206 64.8 3.3 73.3 44.4

26-27.05.07 24136 70.6 3.8 91.7 48.3

27-28.05.07 22995 53.1 3.5 80.5 69.0

28-29.05.07 23621 62.9 3.4 80.3 47.2

29-30.05.07 22708 57.4 3.4 77.2 45.4

The following should be noted with respect to the Effluent Fluoride loads to the river:

1. Leixlip WWTW has a hydraulic capacity in excess of 20,500m3 (not including

Storm Tanks) this is equivalent to approximately 24hours hydraulic detention

time at the measured flows during the survey.

2. The Effluent Samples were taken on a time proportional basis and not a flow

proportional basis as was the case with all the influent samples. This may have

introduced small errors in the calculation of the effluent Fluoride Load.

3. There seems to be a correlation between a significant effluent suspended solids

load and a high Fluoride load see 23-24.05.07 above

4. The effluent load results take no account of the sludge age of the Intel stream of

the wastewater treatment plant. A sludge age of greater than 15 days is typical

for the Intel stream and could significantly effect how quickly fluoride leaves the


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WWTW, fluoride results from two samples taken of the sludge show

concentrations of 1600mg/kg and 1900mg/kg, thus it is clear that some fluoride

is being retained in the sludge in the aeration basin. Some of this fluoride will be

removed when this sludge is dewatered(as detailed in section 2.2). Because of

the sludge age it is possible that fluoride coming into the treatment plant may be

retained in the sludge for some time prior to being discharged to the river and

that the effluent Fluoride load results from this survey may reflect earlier higher

levels of Fluoride load to the plant than those recorded during the survey period.

5. There is also a foaming problem on the surface of the Aeration Basins in the Intel

stream. The source of this foaming has been described as both chemical and

biological and is currently under investigation by Kildare County Council. It is

possible that some fluoride is being retained in the foam and is also contributing

to effluent fluoride levels.

Quantities of Fluoride (measured outside the scope of this survey) have been found in

the sludge from the wastewater treatment plant at a level that would indicate that some

fluoride is being removed from the treatment plant. This is detailed in section 2.2.

2.2 Fluoride removal at the Wastewater Treatment Plant.

As part of the works required for the implementation for the Kildare Sludge Management

Plant composite samples of sludge were sampled at both Osberstown and at Leixlip

WWTW over a period of three weeks commencing November 2001. These composite

samples were taken as daily samples of digested and undigested sludge from both sites

and then each sample was dried to produce a composite dried sample for each week of

sampling.

A description of this work, the accompanying results, and the Sludge Arisings projection

for County Kildare (Taken from the Kildare County Council Sludge Management Plan) are

included in Appendix B. These results from 2001 are shown in the table below:

Osberstown

Undigested

Sludge

mg/kg

Osberstown

Digested

Sludge

mg/kg

Leixlip

Mixed

Sludge

Undigested

mg/kg

Leixlip

Mixed

Sludge

Digested

mg/kg

Sludge

Arisings

Leixlip 2001

Tonnes Dry

Solids/Annum

210 290 2900 3200 894


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Similarly two sludge samples taken from the aeration basin as part of this survey in

2007 also recorded significant levels of Fluoride as follows:

sample 1 sample 2

Leixlip Sludge samples 1600 mg/kg 1900 mg/kg

The Osberstown data is included to show that fluoride is removed with the sludge at

Leixlip at a level approximately 10 times higher than would be typically found. Based on

the figures for Digested Sludge (all Leixlip sludge is digested) and the sludge arisings for

Leixlip in 2001 the total fluoride removed at the treatment plant in 2001 was 2861kg

over the year or approximately 8kg of fluoride a day on average. As follows:

3200mg/kg = 3.2g/kg = 3.2kg/Tonne

3.2kg/Tonne x 894Tonnes / 365 days = 7.83kg/day

Even if it is assumed that no more Fluoride is removed in 2007 than was being removed

in 2001 (current sludge arising are approximately 1600 Tonnes per annum) these figures

do demonstrate that some further fluoride removal is taking place at the Leixlip WWTW

beyond what is removed by the Intel Fluoride treatment process at the Intel Facility.


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3. FLUORIDE ASSIMILATIVE CAPACITY OF THE RIVER LIFFEY

3.1 Survey Measurements carried out in the River Liffey

From the 23-30th of May samples were taken approximately at 12 Noon both upstream

and downstream of the Effluent discharge point from the Leixlip WWTW to the Liffey. The

upstream location is at the Leixlip Bridge and the downstream Location at Lucan Bridge.

The grab samples from this portion of the survey were sent to two laboratories. Lucan

Bridge was selected as it is well below the mixing zone for any effluent and there would

be no possibility of any “plug” flows from the WWTW impacting on the measured

samples. Flow in the River Liffey was also measured courtesy of the ESB. The Liffey is a

controlled river and the ESB control the water spilled from their reservoir and report

their spills to the river, describing the flow at any given time on a daily basis. The time

of year for the survey has been deliberately selected to show the impact on the Liffey

during its low flow period when increases in concentration of Fluoride would be most

noticeable. For every flow sample apart from the sample taken on the 24th May the Liffey

flows were at the mandated minimum of 2m3/sec at the time of sampling (e.g. on the

25th May sample was take at 1200hrs when flow was at 2m3/s. Between 1300hrs and

1800hrs liffey flows were increased to 8m3/hr). During the survey the Liffey was at the

minimum flow for 90% of the time. Liffey flows and fluoride results from the first

Laboratory are presented below.

Liffey Flow and Fluoride Samples

0

3

6

9

12

15

18

24/05/2007 00:00 25/05/2007 00:00 26/05/2007 00:00 27/05/2007 00:00 28/05/2007 00:00 29/05/2007 00:00 30/05/2007 00:00 31/05/2007 00:00

Date

m3/

sec

on

d

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

mg

/l F

luo

rid

e

Liffey Flow

Upstream Fluoride measurement

Downstream Fluoride Measurement


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The results from the first laboratory have been selected as they are the more

conservative results showing increases in the fluoride levels downstream on every day

except where the flow was 8m3/s on the 24th May. (The results from the second

laboratory as detailed in Appendix A do not show downstream increases in Fluoride

concentration on every day and in fact show decreases in fluoride level downstream on

certain days)

Although all the samples are grab samples the following should be noted:

1. The Intel Plant flow to the Leixlip WWTW is very consistent compared to the

Combined Domestic Flow with its Diurnal variations as shown below:

Intel vs. Domestic Influent Flow

0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

800.00

22/05/200700:00

23/05/200700:00

24/05/200700:00

25/05/200700:00

26/05/200700:00

27/05/200700:00

28/05/200700:00

29/05/200700:00

30/05/200700:00

31/05/200700:00Date

M3/

ho

ur

Combined Domestic Flow Intel Flow

Thus it is reasonable, due to the size and balancing effects of the Effluent Balance

Tank (EBT) at the Intel Facility, to assume that the Fluoride load from the WWTW is

also reasonably consistent over the course of a day i.e. no Diurnal peaks and Troughs

in load.

2. The Liffey flow was also very consistent during the survey period and its flow is

definitively known during each sampling event.

3. The Fluoride results for the Liffey were also very consistent in a range of

0.19mg/l to 0.28mg/l Fluoride upstream and a range of 0.19mg/l to 0.36mg/l

downstream.

Because of the high level of consistency and stability seen for all the parameters a

calculation was performed to determine, in light of the known upstream Fluoride


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concentrations, the known flow in the Liffey and the known effluent Fluoride load what

the predicted effluent downstream Fluoride concentration would be.

Date

Liffey Flow m3/s

Upstream Fluoride Concentration mg/l

CalculatedUpstream Fluoride Load Kg/day

Effluent Fluoride Load Kg/day

Calculated Downstream Fluoride Load (Upstream Load + Effluent Load) Kg/day

Predicted Downstream Concentration mg/l

Recorded Downstream Concentration.mg/l

23/05/2007 2.00 0.19 32.83 71.76 104.59 0.61 0.19 24/05/2007 8.00 0.20 138.24 103.74 241.98 0.35 0.19 25/05/2007 2.00 0.24 41.47 76.46 117.93 0.68 0.30 26/05/2007 2.00 0.22 38.02 73.28 111.30 0.64 0.36 27/05/2007 2.00 0.23 39.74 91.72 131.46 0.76 0.34 28/05/2007 2.00 0.23 39.74 80.48 120.23 0.70 0.29 29/05/2007 2.00 0.28 48.38 80.31 128.69 0.74 0.36 30/05/2007 2.00 0.19 32.83 77.21 110.04 0.64 0.21 Average 2.75 0.22 51.41 81.87 133.28 0.64 0.28 There is a significant discrepancy between the Predicted downstream concentration (in

Bold) and the measured downstream concentration. The hardness levels (both total and

calcium hardness) appear to change considerably between the upstream and

downstream sampling locations as detailed below in the following graphs which show

levels of fluoride much lower than they should be and levels of Calcium hardness which

are also decreasing.

Predicted Vs. Recorded Fluoride Concentrations

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

22/05/2007 23/05/2007 24/05/2007 25/05/2007 26/05/2007 27/05/2007 28/05/2007 29/05/2007 30/05/2007 31/05/2007 01/06/2007

Date

mg

/l

Predicted Downstream Fluoride Concentration

Recorded Downstream Fluoride Concentration.

Recorded Upstream Fluoride Concentration


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Calcium Hardness results

0

50

100

150

200

250

300

350

23/05/2007 24/05/2007 25/05/2007 26/05/2007 27/05/2007 28/05/2007 29/05/2007 30/05/2007 31/05/2007Date

mg

/l

0

0.05

0.1

0.15

0.2

0.25

0.3

flu

ori

de

mg

/l

Upstream Calcium Harness

Downstream Calcium Hardness

Upstream Fluoride Concentration

For each of the sampling days the Hardness decreased between the upstream and

downstream location. It should also be noted that the upstream Hardness was at its

lowest on the 29th May corresponding to a slightly higher upstream fluoride

concentration. Measured concentrations of Fluoride downstream are not as high as is

expected and there is a potential relationship between calcium hardness and fluoride

levels in the Liffey. It is well known that, under certain circumstances of pH, Calcium

(Ca) will combine with Fluoride (F) and precipitate out as CaF2 an almost insoluble ionic

compound of calcium and fluorine. (Hard water is difficult to Fluoridate because of this

effect and can require softening prior to Fluoridation). It appears that the Liffey at Leixlip

where the water had an average total hardness over the survey period of 315mg/l is a

very hard water and that this appears to be having the effect of reducing the amount of

biologically available Fluoride in the water as detailed in the following table

Date

Liffey Flow m3/s

Calculated “Predicted” Downstream Fluoride Load (from previous table)

Measured Downstream Fluoride Load Kg/day (based on measured Fluoride Concentrations)

Calculated Downstream Fluoride “Reduction” Kg/day

23/05/2007 2.00 104.59 32.83 71.76 24/05/2007 8.00 241.98 131.33 110.65 25/05/2007 2.00 117.93 51.84 66.09 26/05/2007 2.00 111.30 62.21 49.09 27/05/2007 2.00 131.46 58.75 72.71 28/05/2007 2.00 120.23 50.11 70.11 29/05/2007 2.00 128.69 62.21 66.49 30/05/2007 2.00 110.04 36.29 73.75 Average 2.75 133.28 66.53 66.75


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It should also be noted that in a study carried out by Japanese Scientists on the toxicity

of Calcium Fluoride to marine organisms levels as high as 376mg/l of CaF2 were reported

as having no effect on the organisms probably due to the extremely low concentrations

of fluoride ion in the test solutions, as calculated from the solubility product of calcium

fluoride and the concentration of calcium ion in the natural sea water used.

(Susceptibility of marine organisms to calcium fluoride. Ishio,S; Nakagawa, H Bull. Jap.

Soc. Sci. Fish. Vol. 37, no. 2, pp. 98-104. 1971.)

3.2 Fluoride Assimilative Capacity Calculation

The EPA inspectors report of 11th October 2005 states the following with respect to the

calculation of the allowable Fluoride Load from the Intel Facility: “In response, the

Agency considers that the 95%ile flow is the appropriate value for the calculation of the

assimilative capacity as it provides protection for the receiving waters in the event of low

flows, and, as the information submitted by Intel does not confirm that sufficient fluoride

reduction is taking place in the treatment plant by way of treatment, the requirement to

reduce the mass load of fluoride discharged to LMWWTP by June 2006 is retained in the

RD. The mass limit of 240 kg/day specified by Kildare County Council in the Section 99E

response is to be complied with until that date.”

With respect to the EPA report it should be noted that:

1. Flow in the river Liffey although it is controlled is very similar in nature (if not in

volume) to that of another river in the same catchment namely the Rye, the graph below

shows the daily flows of the two rivers in 2005 for comparison purposes.

Liffey and Rye Flow Comparison

0

5

10

15

20

25

30

35

40

45

01/01/2005 20/02/2005 11/04/2005 31/05/2005 20/07/2005 08/09/2005 28/10/2005 17/12/2005Dates

Lif

fey

Flo

w

0

2

4

6

8

10

12

14

Rye

Flo

w

Liffey

Rye


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As can be seen from the graph the Liffey is a highly reactive river to rainfall events and

the changes in season in a very similar manner to its smaller tributary. The noticeable

differences are in the controlling of peak and trough river flows, where over time peak

flow are stored so that during the low season (may-october) a higher level of minimum

flow is maintained. 2m3/s is not only the 95 percentile flow it is effectively the Dry

Weather Flow and comparatively speaking the Rye has a much lower 95 percentile flow.

The regulation does not refer to Q95 flow it refers to mean annual flow. Six sets of

results from 2006 (all of the most recent data available) have been obtained from the

Central Laboratory of Dublin City Council showing the Fluoride levels both upstream and

downstream of the Leixlip WWTW as far as Islandbridge (where the Liffey becomes tidal)

on no occasion at any of these sites did the fluoride level exceed 0.5mg/l this data is

tabulated below:

Liffey Leixlip Bridge

U/S Lucan Weir

Hermitage Golf Club

Glenaulin Park

Lynches Lane

Downstream Creosote Overflow

Date Fluoride mg/l

Fluoride mg/l

Fluoride mg/l Date

Fluoride mg/l

Fluoride mg/l Fluoride mg/l

06/03/2006 0.12 0.26 0.26 14/02/2006 0.17 0.16 0.22 13/06/2006 0.12 0.28 0.39 11/04/2006 0.18 0.19 0.19 16/10/2006 0.1 0.12 0.11 11/07/2006 0.36 0.35 0.31 05/12/2006 0.13 0.14 0.15 14/11/2006 0.2 0.2 0.25 Average 0.1175 0.2 0.2275 0.2275 0.225 0.2425

It should also be noted that there is an apparent increase in the fluoride level between

Lucan and the Hermitage Golf Club and also between Lynches Lane and the Creosote

Overflow (near Islandbridge) neither of which can be related to Intel activities. This

indicates that there may be other sources, natural and otherwise impacting on the

Fluoride Concentration in the Liffey.

2. According to the EPA Inspector’s Report issued as part of Intel’s IPPC licence

application appeal review (dated 11th October 2005), the proposed licence limit of 80

kg/day was based on the low flow value for the River Liffey (95%ile flow of 2 m3/s) to

attain the Water Quality (Dangerous Substances) Regulations, 2001 (S.I. No. 12 of

2001) EQS of 0.5 mg/l F. During the survey period, 2m3/s was the flow for 90% of the

time and on several occasions the Load exceeded 80 kg/day. Based on the loads

discharged which were in excess of 80 kg/day it would have been expected that the

concentration in the River would have been greater than 0.5 mg/L. The fact that this

was clearly not the case demonstrates that the effect of the fluoride load on the actual

fluoride concentration in the River is not a simple relationship.


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3. Under S.I. No. 294/1989 EUROPEAN COMMUNITIES (QUALITY OF SURFACE WATER

INTENDED FOR THE ABSTRACTION OF DRINKING WATER) REGULATIONS, 1989. The

acceptable level of Fluoride for a water supply to be categorised as Class 1 water (the

very best, requiring minimal treatment) is 1mg/l Fluoride. Under the current drinking

water regulations S.I. No. 106 of 2007 EUROPEAN COMMUNITIES (DRINKING WATER)

REGULATIONS 2007 the minimum design Fluoride level (for water with no naturally

occurring Fluoride) is 0.8mg/l. Not one measured result for Fluoride either taken during

this survey or in fact taken in 2006 by the Dublin Councils would have any impact

whatsoever on the suitability for the waters of the Liffey for abstraction. In fact the

apparent “softening” aspects of the Fluoride to the river is arguably beneficial as is the

fluoridation of the water potentially providing potential cost savings to a downstream

treatment plant both in terms of the costs of Softening Water prior to fluoridation and

also the cost of fluoridation itself.


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4. CONCLUSIONS AND RECOMMENDATIONS

1. The 2001 survey and the sludge results from this 2007 survey show that some

fluoride is present in the sludge and thus is being removed at the Leixlip WWTW.

2. The River portion of the survey has shown that even during low flows and

significant fluoride loads the impact on the fluoride concentration in the River

Liffey is minimal.

3. At no time either during this survey or in 2006 at any other location downstream

of Leixlip WWTW has the Fluoride level exceeded 0.39mg/l (13/6/2006,

Hermitage Golf Club) and because of its location the highest value could not have

been due to effluent from Leixlip WWTW.

4. Analytical results demonstrate that the quantity of measurable dissolved fluoride

(the form taken into consideration in the standard) is considerably lower than

that which would be mathematically predicted because the water hardness is so

high and it is evident that the fluoride has been progressively converted to a non

toxic non biologically reversible or available form (Calcium Fluoride) and therefore

is of no environmental significance. Therefore, the calculation of the Fluoride

Assimilative Capacity in the River Liffey is not a straightforward one as it needs to

take into account the form of fluoride present.

5. A further fluoride survey in both the River and a new extended survey of the post

digestion sludge to confirm the fluoride load removed from the sludge in 2007 is

recommended.

Prepared by

____________________

Peter McNulty

For Nicholas O'Dwyer Ltd


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EPA Export 25-04-2013:23:32:14

APPENDIX A

SURVEY RESULTS


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EPA Export 25-04-2013:23:32:15

APPENDIX B

2001 SLUDGE DATA


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EPA Export 25-04-2013:23:32:15

Flow & Fluoride Report

22 - 30 May 2007

Various Locations associated with

Leixlip Wastewater treatment plants

22 June 2007

Client:

Intel Ireland Limited

Collinstown Industrial Estate

Leixlip

Co. Kildare

Commissioned By:Nicholas O’Dwyer Consulting Engineers

Nutgrove House

Nutgrove Avenue

Dublin 14

Job number 850

Quotation number NQ 850 iv/MMcC/05-07

Date of commencement 22 May 2007

Nutrisolv project manager Mr. M. McConnell

Number of monitoring locations 7

Our Ref: 850/df iii/22-06-07 Page 1 of 21

Nutrisolv Ireland LtdBusiness Innovation Centre, Ballinode, Sligo 1850 266 266 [email protected]


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1.0 Monitoring Programme - location & objectives:

i Monitor the flow and load at the 380 mm inlet channel to the Leixlip wastewater

treatment plant over a 8 day period (in the front garden of No 27 Mill Lane.)

ii Monitor the flow and load at the 750 mm beside a small stream on a footpath

outside no 27 Mill Lane over a 8 day period

iii Monitor the flow and load at the 750 mm inlet channel located by the riverbank

over a 8 day period

iv Sample and conduct analyses on the effluent sample from combined lines at Leixlip

WWTP

v Conduct analyses on samples received from Intel

vi Sample and conduct analyses on river water from the river Liffey at 2 No. Locations

(upstream of the wastewater treatment plan at Leixlip Bridge and Downstream at

Lucan Bridge). Samples were to be split and sent to two separate laboratories for

analyses.

vii A total of 8 daily samples from each of 7 locations (4 No. sampler, 1 No. Intel & 2

No. River locations) were taken for analyses , with split samples being sent to two

different laboratories for river water analyses. 2 No. sludge samples from the

Leixlip WWTP aeration basin were also taken for analysis.

2.0 Methodology

2.1 Flow measurement

Flows were recorded using a Isco 4250 and 750 area velocity logging devices, where the

sensor was mounted at the bottom of the channel. The Isco probe uses Doppler technology to

directly measure the average velocity throughout the flow stream. An integral pressure

transducer measures depth to determine flow area. The flow is calculated by multiplying the




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area of the flow stream by the average velocity. Data was recorded at 2 minute intervals and

hourly, daily and monthly summaries were compiled.

2.2 Sampling

Samples of the influents and the effluent were taken using Isco 6712 programmable samplers

which operated on either time or flow proportional basis dependent upon whether they were

connected to a flow meter.

Daily river samples taken were grab samples.

2.3 Analyses

The following methods were employed for sample analysis:

i pH pH-4500 H+ B Electrochemical

ii Turbidity Robotic Analyser

iii Conductivity Conductivity 2510 B (APHA) Electrochemical

iv TSS 2540 D Total suspended solids

v Fluoride Ion chromatography based on APHA, 1998, 20th

Edition, Method 4110B

vi Alkalinity Colormetric Titration

vii hardness Colormetric Titration

viii Ca Hardness Colormetric Titration

ix TOC Catalytic Oxidation, Infra Red Analysis




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3.0 Results

Reference should be made to the following spreadsheets.

• 850 Leixlip flow.xls

3.1 Flow measurement

Leixlip Influent 750mm Daily Flows, May 2007

Date / Time Average Min Max Totals

m3/h m3/h m3/h m3

23/05/2007 11:00 501.43 304.23 711.82 12034

24/05/2007 11:00 537.94 280.23 691.28 12910

25/05/2007 11:00 503.34 291.76 649.71 12080

26/05/2007 11:00 468.22 236.68 622.69 11237

27/05/2007 11:00 514.18 281.7 677.46 12340

28/05/2007 11:00 516.51 267.97 676.64 12396

29/05/2007 11:00 493.01 245.52 639.44 11832

30/05/2007 10:50 475.28 247.02 629.46 11426




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Intel Influent 750mm Daily Flows, May 2007


m3/h m3/h m3/h m3

23/05/2007 11:00 451.17 394.7 516.1 10828

24/05/2007 11:00 478.2 432.14 512.41 11477

25/05/2007 11:00 450.87 414.25 486.15 10821

26/05/2007 11:00 447.49 417.53 473.14 10740

27/05/2007 11:00 475.81 463.45 491.03 11420

28/05/2007 11:00 430.63 388.08 481.53 10335

29/05/2007 11:00 488.21 451.75 510.39 11717

30/05/2007 10:00 486.31 460.49 509.89 11185

Intel Intel (1) Nutrisolv Daily Mean Max Min

Date Hrly mean daily total daily total Difference Difference DifferenceDifference

m3/hr m3 m3 m3 % % %

22 - 23 /05/07 436.679 10480.289 10828 348 3.3 3.3 3.2

23- 24/05/07 475.131 11403.114 11477 74 0.6 0.6 0.6

24 - 25/05/07 438.671 10528.1 10821 293 2.7 2.8 2.7

25 - 26/05/07 439.129 10539.096 10740 201 1.9 1.9 1.9

26 - 27/05/07 480.148 11523.552 11420 -104 0.9 0.9 0.9

27 - 28/05/07 425.186 10204.464 10335 131 1.3 1.3 1.3

28 - 29/05/07 499.18 11980.32 11717 -263 2.2 2.2 2.2

29 - 30/05/07 487.464 11699.136 11185 -514 4.5 4.6 4.4




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Leixlip Influent 380mm Daily Flows, May 2007


m3/h m3/h m3/h m3

23/05/2007 11:00 11.904 6.0855 16.986 285.7

24/05/2007 11:00 13.069 2.8883 23.412 313.66

25/05/2007 11:00 11.223 4.7211 20.41 269.36

26/05/2007 11:00 9.5321 2.2679 15.816 228.77

27/05/2007 11:00 15.655 5.3056 23.867 375.73

28/05/2007 11:00 10.997 0.3873 37.912 263.93

29/05/2007 11:00 2.9887 -0.71375 13.055 71.728

30/05/2007 11:00 4.0463 1.9616 11.983 97.1109




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Figure 1: Total Flows

12:0

0:00

pm 5

/22/

2007

12:0

0:00

am 5

/23/

2007

12:0

0:00

pm 5

/23/

2007

12:0

0:00

am 5

/24/

2007

12:0

0:00

pm 5

/24/

2007

12:0

0:00

am 5

/25/

2007

12:0

0:00

pm 5

/25/

2007

12:0

0:00

am 5

/26/

2007

12:0

0:00

pm 5

/26/

2007

12:0

0:00

am 5

/27/

2007

12:0

0:00

pm 5

/27/

2007

12:0

0:00

am 5

/28/

2007

12:0

0:00

pm 5

/28/

2007

12:0

0:00

am 5

/29/

2007

12:0

0:00

pm 5

/29/

2007

12:0

0:00

am 5

/30/

2007

0

100

200

300

400

500

600

700

800

900

1000

-20

0

20

40

60

80

100

Flow

750 m

m li

nes m

3/ho

ur

Flow

380 m

m li

ne m

3/Ho

ur

Time & Date

Leixlip 750 mm

Intel 750 mm

Leixlip 380 mm

Figure 2: Daily Flow Trends 22 - 24 May

12:00

:00 pm

5/22

/2007

06:00

:00 pm

5/22

/2007

12:00

:00 am

5/23

/2007

06:00

:00 am

5/23

/2007

12:00

:00 pm

5/23

/2007

06:00

:00 pm

5/23

/2007

12:00

:00 am

5/24

/2007

06:00

:00 am

5/24

/2007

12:00

:00 pm

5/24

/2007

0

100

200

300

400

500

600

700

800

900

1000

0

10

20

30

40

50

60

70

80

90

100

750m

m Flo

w m3

/hour

380 m

m Flo

w m3

/hour

Time & Date

Leixlip Influent 750mm

Intel Influent 750mm

Leixlip Influent 380mm




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3.2 Analytical Results

Intel Influent to Leixlip WWTP

Date Cert. No. pH Turbidity TSS Fluoride Flow Fluoride

m3 kg

22-23.05.07 12015 6.6 33 66 5.6 10828 61

23-24.05.07 12026 6.8 16 42 5.1 11477 59

24-25.05.07 12033 6.9 35 57 5.3 10821 57

25-26.05.07 12051 6.8 440 110 5.4 10740 58

26-27.05.07 12052 7 72 110 5.5 11420 63

27-28.05.07 12053 6.6 1300 630 4.4 10335 45

28-29.05.07 12077 6.7 160 150 4.8 11717 56

29-30.05.07 12093 6.6 120 120 4.6 11185 51

No 8 8 8 8 8 8

Min 6.6 16 42 4.4 10828 45

Max 7 1300 630 5.6 11717 63

Mean 6.75 272 160.63 5.09 11065 56

Median 6.8 120 110 5.3 11185 58

Note : All results are as mg/l except pH (units) and turbidity (NTU) unless otherwise

indicated.




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Influent to Leixlip WWTP 750 mm Pipe


m3 kg

22-23.05.07 12016 6.8 89 95 0.59 12034 7

23-24.05.07 12022 6.7 130 85 0.57 12910 7

24-25.05.07 12034 7.1 230 200 0.59 12080 7

25-26.05.07 12063 7 230 250 0.6 11237 7

26-27.05.07 12064 7.1 230 250 0.61 12340 8

27-28.05.07 12065 7.1 270 240 0.6 12396 7

28-29.05.07 12078 6.9 420 250 0.56 11832 7

29-30.05.07 12094 6.9 410 140 0.52 11426 6

No 8 8 8 8 8 8

Min 6.7 89 85 0.52 12034 6

Max 7.1 420 250 0.61 12910 8

Mean 6.95 251.13 188.75 0.58 12032 7

Median 7 230 240 0.59 12080 7


indicated




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Influent to Leixlip WWTP 380 mm Pipe


m3 kg

22-23.05.07 12017 7.1 140 160 0.62 285.7 0.18

23-24.05.07 12023 6.9 130 150 0.63 313.66 0.2

24-25.05.07 12036 6.8 330 370 0.66 269.36 0.18

25-26.05.07 12066 6.4 1600 2100 0.47 228.77 0.11

26-27.05.07 12067 6.7 290 270 0.68 375.73 0.26

27-28.05.07 12068 6.8 290 230 0.68 263.93 0.18

28-29.05.07 12079 6.7 130 250 0.06 71.73 0

29-30.05.07 12095 6.3 1500 700 0.55 97.11 0.05

No 8 8 8 8 8 8

Min 6.3 130 150 0.06 71.73 0

Max 7.1 1600 2100 0.68 375.73 0.26

Mean 6.71 551.25 528.75 0.536 238.25 0.14

Median 6.8 290 270 0.63 269.36 0.18


indicated




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Effluent Sample Leixlip WWTP

Date Cert. No. pH Turbidity TSS Fluoride

22-23.05.07 12018 7.5 1.8 4 3.1

23-24.05.07 12025 7.3 4.4 18 4.2

24-25.05.07 12037 7.1 4 3 3.3

25-26.05.07 12069 7.1 3 <3.0 3.3

26-27.05.07 12070 7.1 4 <3.0 3.8

27-28.05.07 12071 7 4 3 3.5

28-29.05.07 12080 6.7 3 <3.0 3.4

29-30.05.07 12096 6.8 3 2 3.4

No 8 8 8 8

Min 6.7 1.8 <3.0 3.1

Max 7.5 4.4 18 4.2

Mean 7.1 3.4 3.75 3.5

Median 7.1 4 3 3.4

Note : All results are as mg/l except pH (units) and turbidity (NTU) unless

otherwise indicated




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Intel Plant Sample

Date Cert. No. pH Turbidity TSS Fluoride

22-23.05.07 12021 6.6 10 9 5.2

23-24.05.07 12024 6.8 14 22 5.2

24-25.05.07 12035 6.9 15 13 5.2

25-26.05.07 12060 7 10 130 5.8

26-27.05.07 12061 7 14 12 5.3

27-28.05.07 12062 6.9 16 13 4.8

28-29.05.07 12076 6.7 12 12 5

29-30.05.07 12092 6.7 13 15 5.1

No 8 8 8 8

Min 6.6 10 9 5.2

Max 6.7 13 15 5.1

Mean 6.8 13 28 5.2

Median 7 14 12 5.3

Note : All results are as mg/l except pH (units) and turbidity (NTU) unless

otherwise indicated




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Summary

Total Influent Effluent

Daily Flow Fluoride Fluoride

m3 (1) kg kg

22-23.05.07 23148 67.92 71.76

23-24.05.07 24701 66.09 103.74

24-25.05.07 23170 64.66 76.46

25-26.05.07 22206 64.85 73.28

26-27.05.07 24136 70.59 91.72

27-28.05.07 22995 53.09 80.48

28-29.05.07 23621 62.87 80.31

29-30.05.07 22708 57.45 77.21

No 8 8 8

Min 23148 53.09 71.76

Max 24701 70.59 103.74

Mean 23336 63.44 81.87

Median 23170 64.85 80.31

1. Assumes influent flow and effluent flow are the same. No allowance has been made

for or load retention time in the calculation of effluent loads.

Sludge Results

Date Cert. No. Fluoride

mg/l

26.05.07 12072 4.5

28.05.07 12073 4.2




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River results:

Lab 1:

Upstream of Leixlip WWTP

Date Cert No. Fluoride Alk H/ness H/ness EC TSS pH TOC Temp

Total Calcium

mg/l mg/l mg/l mg/l us/cm mg/l units mg/l oC

23.05.07 12019 0.19 270 320 274 570 <3.0 7.7 <7.0 13.9

24.05.07 12027 0.2 292 340 260 688 <3.0 7.6 <7.0 14

25.05.07 12038 0.24 270 320 290 600 <3.0 7.9 <7.0 13.7

26.05.07 12054 0.22 270 330 280 490 <3.0 7.9 <7.0 13.9

27.05.07 12055 0.23 270 340 278 610 <3.0 7.9 <7.0 14.1

28.05.07 12056 0.23 270 320 274 590 <3.0 7.9 <7.0 14.2

29.05.07 12074 0.28 170 230 162 460 3 7.7 <7.0 14.3

30.05.07 12090 0.19 270 330 274 610 <3.0 7.8 <7.0 13.9

No 8 8 8 8 8 8 8 8 8

Min 0.19 170 230 162 460 <3.0 7.6 <7.0 13.7

Max 0.28 292 340 290 688 3 7.9 <7.0 14.3

Mean 0.18 260 316 262 577 <3.0 7.8 <7.0 14

Median 0.23 270 330 274 600 <3.0 7.9 <7.0 14




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EPA Export 25-04-2013:23:32:15

Downstream of Leixlip WWTP

Date Cert No. F Alk H/ness H/ness EC TSS pH TOC Temp

Total Calcium


23.05.07 12020 0.19 200 240 220 460 <3.0 7.8 <7.0 13.9

24.05.07 12028 0.19 200 220 176 350 8 7.7 <7.0 14.1

25.05.07 12039 0.3 190 240 198 540 5 8 7.4 14

26.05.07 12057 0.36 180 220 192 650 6 7.6 7.1 14.1

27.05.07 12058 0.34 180 220 184 390 <3.0 7.7 <7.0 14.2

28.05.07 12059 0.29 160 200 198 440 <3.0 7.7 7.5 14.2

29.05.07 12075 0.36 170 230 98 460 4 7.7 <7.0 14.2

30.05.07 12091 0.21 170 240 80 480 5 7.8 <7.0 13.9

No 8 8 8 8 8 8 8 8 8

Min 0.19 160 200 80 350 <3.0 7.6 <7.0 13.9

Max 0.36 200 240 220 650 8 8 7.5 13.9

Mean 0.23 181 226 168 471 3.5 7.75 <7.0 14.1

Median 0.3 180 230 192 460 5 7.7 <7.0 14.2




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Lab 2:

Note: limits of detection for TSS and single high TSS result (cert 12074) have been

queried with the subcontractor laboratory for both sets of samples.

Upstream of Leixlip WWTP


Total Calcium


23.05.07 12019 0.3 294 340 274 654 <10 8 5 13.9

24.05.07 12027 0.3 292 340 258 669 <10 8 5 14

25.05.07 12038 0.2 292 336 290 663 <10 7.8 3 13.7

26.05.07 12054 0.1 296 322 276 666 <10 7.8 5 13.9

27.05.07 12055 0.2 292 330 276 663 <10 7.9 3 14.1

28.05.07 12056 0.5 302 332 278 662 <10 7.8 3 14.2

29.05.07 12074 0.09 198 208 160 436 98 8 4 14.3

30.05.07 12090 0.3 288 334 272 651 <10 8 6 13.9

No 8 8 8 8 8 8 8 8 8

Min 0.09 198 208 160 436 <10 7.8 3 13.7

Max 0.5 302 340 290 669 98 8 6 14.3

Mean 0.24 281.75317.75 260.5 633 12.25 7.9 4.25 14

Median 0.3 292 334 276 663 <10 8 5 14




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EPA Export 25-04-2013:23:32:15

Downstream of Leixlip WWTP


Total Calcium


23.05.07 12020 0.3 218 250 230 654 <10 8 5 13.9

24.05.07 12028 0.1 216 222 174 458 <10 8.1 4 14.1

25.05.07 12039 0.2 210 238 194 520 <10 7.7 5 14

26.05.07 12057 0.2 198 228 194 523 <10 7.7 4 14.1

27.05.07 12058 0.3 200 238 188 519 <10 7.8 4 14.2

28.05.07 12059 0.2 184 204 194 459 <10 7.8 4 14.2

29.05.07 12075 0.09 178 202 102 458 11 7.8 5 14.2

30.05.07 12091 0.3 188 218 84 503 <10 7.7 3 13.9

No 8 8 8 8 8 8 8 8 8

Min 0.09 178 202 84 458 <10 7.7 3 13.9

Max 0.3 218 250 230 654 11 8.1 5 14.2

Mean 0.2 199 225 170 512 1.4 7.8 4.3 14.1

Median 0.2 200 228 194 519 <10 7.8 4 14.1




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EPA Export 25-04-2013:23:32:15

Site Notes:

i. Times presented for hourly flow reflect the flow for the previous 60 minutes.

ii. Times presented for daily flow, reflect flow from 11.00 hrs the previous day unless

otherwise indicated, ie 25/05/07 11:00 represents the time period from 11:01 hours

on 24/05/07 until 11:00 hours on 25/05/07.

iii. Flow was measured commenced on 22/05/07 at 12.00 hrs and continued up to 11.00

hrs on 30/05/07, the time of the final data download.

iv. No significant incident occurred during the programme that could have affected

results in any way.

v. Weather was generally fair throughout the monitoring period with little to no rain.

vi. 22-05-07: Installation:

a. 3 No. Sampler/flowmeters were installed at the following locations:

b. Intel Influent Line,River Bank (750mm Diameter)

c. Leixlip Influent Line (750mm Diameter)

d. Leixlip Influent Line (380mm Diameter)

e. 1 No. sampler was installed on the combined effluent line of Leixlip

WWTW.

f. All samplers and flowmeters were programmed to start sampling at 11:00

hrs

g. Flowmeters were calibrated prior to installation.

vii. 23.05.07

a. All sample volumes taken correctly.

b. Data was downloaded and checked on site for each influent location.

c. Grab samples were taken both upstream and downstream from leixlip

treatment plant at Leixlip and Lucan bridges respectively. Samples were

taken at approximately 12:00 hrs.

d. Instant Flow Readings:

• Intel In (750mm): 452.62 m3/hr




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EPA Export 25-04-2013:23:32:15

• Leixlip In (750mm): 491.23 m3/hr


viii. 24.05.07


b. Data was downloaded and checked on site.





• Intel In (750mm): 436.78 m3/hr



ix. 25.05.07







• Intel In (750mm): 411.98 m3/hr

• Leixlip In (750mm): 532. 11 m3/hr


x. 26.05.07


b. Grab samples were taken both upstream and downstream from leixlip






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EPA Export 25-04-2013:23:32:15

xi. 27-05-07


b. Grab samples were taken both upstream and downstream from leixlip



xii. 28.05.07







• Intel In (750mm): 426.22 m3/hr



xiii.29.05.07







• Intel In (750mm): 503.53 m3/hr



xiv.30.05.07





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EPA Export 25-04-2013:23:32:15






• Intel In (750mm): 493.36 m3/hr



e. All equipment was decommissioned and flowmeters calibration was

rechecked.. There was a 0% fluctuation in calibration at all three locations.




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EPA Export 25-04-2013:23:32:15


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EPA Export 25-04-2013:23:32:15


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EPA Export 25-04-2013:23:32:15

Attachment F.2 Tabular Data on Drinking Water Abstraction Point(s) Not applicable as no downstream or down gradient drinking water abstraction points.


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EPA Export 25-04-2013:23:32:15

for inspection purposes only. · ∙ contract 4 (m&e works) w 3,749,000 ∙ network (m3...

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