Dublin Bay Bathing Water Quality Dublin City Council – Environment Strategic Policy Committee November 2018 Irish Water
Bathing Water Quality Sources of Pressure • Urban Wastewater – Wastewater Treatment Plants – Storm Water Overflows • Storm water (Urban) Run-Off • Agricultural Sources • Misconnections • Pollution from Other Sources (Seabirds & Animals) Aim of Bathing Water Quality Regulations • Reduce risk to bathers from bacterial pollution • Establish pro-active approach to assessment of pollution risks and management of bathing waters • Promote increased public involvement & communication of information on bathing water quality 2
1 Ringsend WWTP Upgrade
Overview of Ringsend WwTP site WWTP Plant Overloaded: • Non-compliant with Urban Wastewater Treatment Directive – ECJ Case • Non-compliant with EPA Wastewater Discharge Licence 4
Project Scope Project Strategy – Biological Nutrient Removal • Achieve UWWTD & Licence compliant effluent for “sensitive waters” through improved treatment retaining existing sea outfall. • Provide compliance and capacity to service growth in 2 Phases: 1. Capacity Upgrade with nutrient removal technology. Additional Capacity 400,000 Population Equivalent (PE). 2. Retrofit existing Sequencing Batch Reactors (SBRs) with nutrient removal technology to bring total capacity up to 2,400,000 PE. Planning Approvals • Phase 1 doesn’t require Planning Approval. Capacity Upgrade provided under existing Planning Approval. • Phase 2 requires Planning Approval. 5
Nutrient Removal Technology (AGS) Process Proving Step 1 PPS1 completed in 2016. Process Proving Step 2 PPS2 construction complete June 2017 Testing period start-up July 2017 Various loadings scenarios tested PPS2 Signed Off 6
Ringsend - Current Project Status • Ringsend SID Planning Application • Submitted in June 2018 • Allowance of 1 year for application – anticipated grant of approval in Q3 2019 • Capacity Upgrade Contract (under current planning approval) • Contract commenced Q4 2017 • Required to achieve compliance with UWWTD and capacity requirements ECJ infringement case/ Dublin region growth • Retrofit Stage 1 Contract (new approval required) • In Tender process at present • Commence construction Q3/Q4 2019 subject to Planning Approval 7
Water Quality Modelling • Water Quality Impact Assessment prepared for Environmental Impact Assessment Report (EIAR) • Model Runs produce Plots for E Coli during Bathing Season for: – Increased flow rates for future scenario – Modelling at licence limit for E Coli: 100,000 E Coli/100ml • Note : Average E Coli discharge measured in 2018 was 32,000 E Coli/100ml. 32% of license limit value 8
Future Scenario (2.4M PE): Discharge during Bathing Season Everything in Blue is at Good Quality below 500 E Coli/100ml 95%ile. Everything in White is at Excellent Quality below 250. 9
Future Scenario (2.4M PE): Discharge during Bathing Season – Storm Event Everything in Blue is at Good Quality below 500 E Coli/100ml 95%ile. Everything in White is at Excellent Quality below 250. 10
2 Storm Water Overflows
Storm Water Overflows To WWTW To River 12
Wastewater Networks Key Challenges: 40% network not in GIS. 30% network based on poor/low confidence data. Majority Network Models out of date/ low confidence Solutions: 1. Drainage Area Plans (DAPs) 2. Wastewater Network Wastewater Networks – in GIS Programmes & Projects 13
Need for DAPs The DAP - investigation of the failure mechanisms causing service failures on the network using a verified hydraulic model Pollution Incidents Climate Change Growth Sewer Flooding Urban Creep High Level DAP Assessment for Investment Planning Investment Needs & Notional Solutions Detailed DAP Assessment for Project Planning Prioritised Costed Solutions within a Plan and Programme 14
DAP Process 4 Stages in DAP Process • Stage 1 : Data Gathering • Stage 2 : Model Build • Stage 3: Risk Assessment • Stage 4: Assess Options & Design Development 15
DAP Stage 2 - Asset Surveys FC IG Manhole Surveys B, CXI IG SA, DES IR, CXI B Pipe (Sewer) Surveys B Break CXI Defective Intruding Connection DES Deposits - Silt FC Fracture Circumferential B IG Infiltration Gushing IR Infiltration Running SA | Social Media Dublin 2018 Survey Abandoned 16
DAP Stage 2 Flow Monitoring Model Verification 17
Dublin Bay – Wastewater Catchments North Fringe 9C Sewer & North Dublin Drainage Scheme Leixlip WWTP Lower Liffey City Centre Valley Ringsend Catchment WWTP Rathmines & Pembroke 9B Sewer Dodder Valley Sewer West Pier 9B Sewer B Bray & Shanganagh Shanganagh WWTP
Storm Water Overflows Catchment No. of DAP DAP Storm Water in Status End Overflows Place Q4 (SWOs) (Consultant) 2018 Dodder Valley 23 Y (WSP) Stage 2 Rathmines & 24 Y (Atkins) Stage 2 Pembroke North Fringe / 87 Y (RPS) Stage 2 North Dublin Drainage Scheme City Centre 88 Y (Atkins) Stage 4 West Pier 29 Y (WSP) Stage 2 19
SWO Identification SWO’s City Centre SWO’s North Fringe/NDDS 20
Capacity Mapping – Wet Day % Capacity Remaining 21
Critical Asset Failure Main Lift Pumping Station Flooding & Pollution 22
3 Wastewater Networks Other Initiatives
Wastewater Network Programmes & Projects National Programmes Storm Water Overflow (SWO) Survey, Assessment & Monitoring Programme (€6M) Sewer Rehabilitation Programme (€52M) Wastewater Pumping Station Telemetry Programme (€7M) Wastewater Pumping Station Capital Maintenance Programme (Dublin City Only) Investment Plan Projects Doldrum Bay North & South Docklands Progression of Infrastructure Projects – Subject to DAP outputs City Centre WW Network Rathmines & Pembroke WW Network Dodder Valley Reinforcement WW Network NDDS Reinforcement WW Network 24
Sewer Rehabilitation Programme INSPECTION CONDITION PLANNING ASSESSMENT REGULATORY CONDITION SELECTION REPORTING ASSESSMENT PROCESS SPECIMEN DESIGN & COSTING DETAILED DESIGN/DELIVERY | 25
Sewer Rehabilitation Prioritisation TOTAL TOTAL RIS K TOTAL US DS S truc tural Pipe S truc tural C apac ity - Drainage US width DS width US height DS height US pipe DS pipe C C TV S truc tural S truc tural S truc tural L IK L IHOOD S C ORE - R ank Agglomeration US node ID DS node ID s hape s hape Total C ONS E QUE NC E Material C ondition Infiltration C ode (mm) (mm) (mm) (mm) material material S urvey Date C ondition Mean S c ore Peak S c ore S C OR E - ID ID S c ore S C OR E [WOR K S ] [WOR K S ] [WOR K S ] WORK S WOR K S 508 1 Galway C ity D0050 S M29245901 S M29245903 C C 0 0 300 300 VC VC 05/07/2005 5 145.45 240 320 4.06 25 100 0 125 2 Galway C ity D0050 S M29245902 S M29245907 C C 0 0 375 375 VC VC 05/07/2005 5 40 240 720 4.06 25 100 0 125 507 479 3 R amelton D0341 S C 22212106 S C 22212107 C C 0 0 225 225 PVC C O 16/05/2013 5 14.72 165 371 3.99 20 100 0 120 450 4 E nnis c orthy D0029 S S 97393503 S S 97393510 C C 0 0 225 225 C O VC 20/08/2013 5 12.28 200 684 3.60 25 100 0 125 5 E nnis c orthy D0029 S S 97396902 S S 97395901 C R 0 600 225 700 VC 02/10/2013 5 200 320 320 3.49 25 100 0 125 436 6 R amelton D0341 S C 22216105 S C 22216101 C C 0 0 225 225 C O C O 02/07/2013 5 3.8 240 240 3.49 10 100 15 125 436 431 7 R amelton D0341 S C 22214003 S C 22214101 C C 0 0 150 150 C O C O 13/05/2013 5 6.24 210 300 3.92 10 100 0 110 427 8 C arrigart D0523 S C 12369401 S C 12369502 C C 0 0 150 150 C O C O 20/02/2013 5 231.11 560 16640 3.89 10 100 0 110 9 K ilmac reannan D0513 S C 14201302 S C 14201401 C C 0 0 225 225 C O C O 09/04/2013 5 9.07 165 360 3.39 10 100 15 125 424 423 10 Downings D0350 S C 09389210 S C 09389203 C C 0 0 150 150 VC VC 19/09/2013 5 5.63 165 165 3.39 25 100 0 125 26
Criticality & Risk – Thematic Mapping 27
4 Key Actions
Key Actions • Completion of DAPs with extension of Water Quality Model for Dublin Bay to enable effective and risk based decisions to be made on future investment to achieve compliance and provide for growth • Maximise utilisation and resilience of existing Wastewater Assets • Promote and collaboration on Stormwater Management and application of Sustainable Drainage. • Continued Communication with Stakeholders & Public 29
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