Dublin Bay

Bathing Water Quality

Dublin City Council – Environment Strategic Policy Committee

November 2018

Irish Water

2

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

1 Ringsend WWTP Upgrade

Overview of Ringsend WwTP site

4

WWTP Plant Overloaded:

• Non-compliant with Urban Wastewater Treatment Directive – ECJ Case

• Non-compliant with EPA Wastewater Discharge Licence

5

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.

6

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

7

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

8

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

9

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.

10

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.

2 Storm Water Overflows

12

Storm Water Overflows

To River

To WWTW

1. Drainage Area Plans (DAPs)

2. Wastewater Network Programmes & Projects

13

Wastewater Networks

40% network not in GIS.

30% network based on poor/low confidence data.

Majority Network Models out of date/ low confidence

Solutions:

Wastewater Networks – in GIS

Key Challenges:

The DAP - investigation of the failure mechanisms causing service failures on the network using

a verified hydraulic model

14

Need for DAPs

Investment Needs & Notional Solutions

Prioritised Costed Solutions

within a Plan and Programme

High Level DAP

Assessment for

Investment Planning

Detailed DAP Assessment

for Project Planning

Sewer Flooding

Pollution Incidents GrowthClimate Change

Urban Creep

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 Process

| Social Media Dublin 201816

IR, CXI

FC

B, CXI

B

B

IG

IG

B Break

CXI Defective Intruding Connection

DES Deposits - Silt

FC Fracture Circumferential

IG Infiltration Gushing

IR Infiltration Running

SA Survey Abandoned

SA, DES

Manhole

Surveys

Pipe (Sewer)

Surveys

DAP Stage 2 - Asset Surveys

17

DAP Stage 2

Model VerificationFlow Monitoring

9C Sewer

North Fringe

&

North Dublin Drainage Scheme

City Centre

Rathmines &

Pembroke

Dodder Valley Sewer

B

Bray

&

Shanganagh

9B Sewer

Lower Liffey

Valley

Catchment

West Pier

9B Sewer

Ringsend

WWTP

Leixlip

WWTP

Shanganagh

WWTP

Dublin Bay – Wastewater Catchments

19

Storm Water Overflows

Catchment No. of

Storm Water

Overflows

(SWOs)

DAP

in

Place

(Consultant)

DAP

Status End

Q4

2018

Dodder Valley 23 Y (WSP) Stage 2

Rathmines &

Pembroke

24 Y (Atkins) Stage 2

North Fringe /

North Dublin

Drainage

Scheme

87 Y (RPS) Stage 2

City Centre 88 Y (Atkins) Stage 4

West Pier 29 Y (WSP) Stage 2

20

SWO Identification

SWO’s City Centre

SWO’s North

Fringe/NDDS

21

Capacity Mapping – Wet Day

% Capacity Remaining

22

Critical Asset Failure

Flooding & Pollution

Main Lift Pumping Station

3 Wastewater Networks Other Initiatives

24

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

|25

INSPECTION PLANNING

SPECIMEN DESIGN & COSTING

CONDITION ASSESSMENT

SELECTION PROCESS

DETAILED DESIGN/DELIVERY

CONDITION ASSESSMENT

REGULATORY REPORTING

Sewer Rehabilitation Programme

26

Sewer Rehabilitation Prioritisation

1 Galway City D0050 SM29245901 SM29245903 C C 0 0 300 300 VC VC 05/07/2005 5 145.45 240 320 4.06 25 100 0 125 508

2 Galway City D0050 SM29245902 SM29245907 C C 0 0 375 375 VC VC 05/07/2005 5 40 240 720 4.06 25 100 0 125 507

3 Ramelton D0341 SC22212106 SC22212107 C C 0 0 225 225 PVC CO 16/05/2013 5 14.72 165 371 3.99 20 100 0 120 479

4 Enniscorthy D0029 SS97393503 SS97393510 C C 0 0 225 225 CO VC 20/08/2013 5 12.28 200 684 3.60 25 100 0 125 450

5 Enniscorthy D0029 SS97396902 SS97395901 C R 0 600 225 700 VC 02/10/2013 5 200 320 320 3.49 25 100 0 125 436

6 Ramelton D0341 SC22216105 SC22216101 C C 0 0 225 225 CO CO 02/07/2013 5 3.8 240 240 3.49 10 100 15 125 436

7 Ramelton D0341 SC22214003 SC22214101 C C 0 0 150 150 CO CO 13/05/2013 5 6.24 210 300 3.92 10 100 0 110 431

8 Carrigart D0523 SC12369401 SC12369502 C C 0 0 150 150 CO CO 20/02/2013 5 231.11 560 16640 3.89 10 100 0 110 427

9 Kilmacreannan D0513 SC14201302 SC14201401 C C 0 0 225 225 CO CO 09/04/2013 5 9.07 165 360 3.39 10 100 15 125 424

10 Downings D0350 SC09389210 SC09389203 C C 0 0 150 150 VC VC 19/09/2013 5 5.63 165 165 3.39 25 100 0 125 423

Capacity -

Infiltration

[WORKS]

DS height

(mm)

US pipe

material

Structural

Condition

US width

(mm)

DS width

(mm)

US height

(mm)

Structural

Mean Score

Structural

Peak Score

Structural

Total

Score

Agglomeration

DS

shape

ID

US node ID DS node ID

US

shape

ID

Drainage

Code

DS pipe

material

CCTV

Survey Date

TOTAL

LIKLIHOOD

SCORE -

WORKS

TOTAL RISK

SCORE -

WORKS

TOTAL

CONSEQUENCE

SCORE

Pipe

Material

[WORKS]

Structural

Condition

[WORKS]

Rank

27

Criticality & Risk – Thematic Mapping

4 Key Actions

29

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