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Water Services Network Management Grellan McGrath Steven Blennerhassett RPS Consulting Engineers 1.

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Presentation on theme: "Water Services Network Management Grellan McGrath Steven Blennerhassett RPS Consulting Engineers 1."— Presentation transcript:

1 Water Services Network Management Grellan McGrath Steven Blennerhassett RPS Consulting Engineers 1

2 Mizen Footbridge 2

3 ? 3

4 4

5 World Water Day – 22 nd March When the well is dry, we know the value of water – Benjamin Franklin 5

6 World Water Day – 22 nd March 6

7 A Brief History of Cork Citys Water Supply Cork Pipe Water Company Established Timber distribution pipes, 20ft long – 2 ½ to 3 ø Cork Bridges, Waterworks and Improvement Act Cast iron mains introduced – network extended – Filter tunnel constructed intense waste water campaign due to efforts of city engineer and inspectors reduced consumption from 70 to 38 gal/p/d (172 l/p/d) 1928 – Sand filters installed 1940s - new high level reservoir built as an unemployment relief scheme 1956 – New filters and sedimentation plant 7

8 Define / Review Levels of Service Define / Review Levels of Service Demand Assessment Demand Assessment Collect Network Asset Data Collect Network Asset Data Capacity Assessment Capacity Assessment Improvement Options Improvement Options Management Plan Financial Plan Water Network Management Water Network Management 8 Network Planning Review & Improve Review & Improve

9 Statutory Water Quality – SI 278/2007 Customer Service Pressures -15 to 40m Head Define / Review Levels of Service Define / Review Levels of Service Other Service Standards Leakage - Economic Level Fireflows – 8 to 75 l/s depending on area served Service Storage - 24 hr 9 Levels of Service Network Planning

10 Current Demand - Water Audit Demand Assessment Demand Assessment 10 Demand Assesment Network Planning

11 Demand Assessment Demand Assessment Distribution Input (DI) Accounted for Water (AFW) Measured or assessed lergitimate water use Unaccounted for Water (UFW) = DI - AFW Domestic Demand Households x Occupancy x pcc Non-Domestic Demand Metered consumption Operational Use – 2% of DI Permanent Domestic Seasonal Domestic Peaking Factor – Average Day/Peak Week 11 Current Demand - Water Audit Demand Assesment Network Planning

12 Demand Assessment Demand Assessment Demand Management Reduce water consumption Reduce water losses 12 Current Demand Demand Assesment Network Planning

13 Demand Assessment Demand Assessment Future Demand Population growth (25-Year Horizon) -Top Down: Planning guidelines, CSO - Bottom Up: Availability of zoned land Demand – Domestic demand as per audit using projected pcc, losses etc. - Non-domestic demand growth in line with domestic -UFW in line with level of service objectives. 13 Demand Management Current Demand Demand Assesment Network Planning

14 14 Collect Network Asset Data Collect Network Asset Data Asset Data - National Water Study 2000 Length of network (size, age, material, condition, performance) Number/capacity of pumping stations Number and total volume of storage reservoirs Value of total asset (Modern Equivalent Asset (MEA) value) Value of assets to be replaced over next 5 years (MEA value) Annual operating and maintenance costs. Network Planning

15 15 Capacity Assessment Capacity Assessment Asset Capacity Assessment Design Horizon Demand / Capacity Yrs Yrs0 - 5 Yrs Yrs Yrs Rated Asset Capacity Projected Demand Range Capacity Shortfall Expected Time Range of Deficit Network Planning

16 16 Capacity Assessment Capacity Assessment Design Horizon Demand / Capacity Yrs Yrs0 - 5 Yrs Yrs Yrs Expected Time Range of Deficit Increased Asset Capacity Rated Asset Capacity Asset Capacity Assessment Network Planning

17 17 Improvement Options Improvement Options Network Planning Improvement Options Assess Capacity Requirement Can it be satisfied by Rehab/renewal option? No Can it be satisfied by Augmentation Option? No Can it be satisfied by Upgrade/Replacement? No Yes Proceed with selected option Yes Can it be satisfied by Operational Optimisation?

18 18 Management Plan Management Plan Asset Inventory – As per NWS Operational Plan – Summary of primary objectives in the operational plan and any sub-plans Maintenance Plan – Summary of the planned asset maintenance. Rehabilitation/Renewal Plan – Summary of the planned asset rehabilitation/renewal activities. Asset Replacement – Summary of the planned asset replacement. Network Planning

19 Financial Planning Financial Plan Operation and Maintenance Expenditure Interest Expenditure (if any) Asset Depreciation Funding for Historic Under-investment Funding for Service Enhancement Funding for System Growth Funding for Loan Repayment Just covering cash costs Covering cash costs and providing for maintaining current asset condition – no planning for the future Sustainable level of expenditure to cover future investment needs Water Services Expenditure Requirements 19 Network Planning

20 Levels of Service Demand for Water Services Asset Management Finance 20 Review Network Planning Review & Improve Review & Improve

21 21 European Communities (Drinking Water) (No. 2) Regulations 2007 S.I. No. 278 of 2007 Came into immediate effect on 12 June 2007 Legislation

22 22 Ensure Quality (Regulation 4) No.Parameter Value (no./100ml) 1 Escherichia coli (E. coli) 0 2Enterococci0 Table A Microbiological Parameters Table A Microbiological Parameters Legislation

23 23 Ensure Quality (Regulation 4) No.ParameterValue (μg/l) 3Acrylamide0.10 4Antimony5.0 5Arsenic10 6Benzene1.0 7Benzo(a)pyrene0.01 8Boron1.0 mg/l 9Bromate10 Cadmium5.0 11Chromium50 12Copper2.0 mg/l 13Cyanide50 141,2-Dichloroethane3.0 15Epichlorohydrin Fluoride (a) fluoridated supplies 0.8 mg/l Fluoride (b) naturally occurring fluoride, not needing further fluoridation 1.5 mg/l No.ParameterValue (μg/l) 17 Lead – to 24/12/1325 Lead – from 25/12/ Mercury1.0 19Nickel20 Nitrate50 mg/l 21Nitrite0.5 mg/l 22Pesticides0.1 23Pesticides Total0.5 24PAH0.1 25Selenium10 26 Tetrachloroethene and Trichloroethene 10 27Trihalomethanes – Total100 28Vinyl chloride0.5 Table B Chemical Parameters Legislation

24 24 Ensure Quality (Regulation 4) No.ParameterValue (μg/l) 3Acrylamide0.10 4Antimony5.0 5Arsenic10 6Benzene1.0 7Benzo(a)pyrene0.01 8Boron1.0 mg/l 9Bromate10 Cadmium5.0 11Chromium50 12Copper2.0 mg/l 13Cyanide50 141,2-Dichloroethane3.0 15Epichlorohydrin Fluoride (a) fluoridated supplies 0.8 mg/l Fluoride (b) naturally occurring fluoride, not needing further fluoridation 1.5 mg/l No.ParameterValue (μg/l) 17 Lead – to 24/12/1325 Lead – from 25/12/ Mercury1.0 19Nickel20 Nitrate50 mg/l 21Nitrite0.5 mg/l 22Pesticides0.1 23Pesticides Total0.5 24PAH0.1 25Selenium10 26 Tetrachloroethene and Trichloroethene 10 27Trihalomethanes – Total100 28Vinyl chloride0.5 Table B Chemical Parameters No.ParameterValue (μg/l) 17 Lead – until 24 th December Lead – from 25 th December Legislation

25 25 Ensure Quality (Regulation 4) No.ParameterValue (μg/l) 3Acrylamide0.10 4Antimony5.0 5Arsenic10 6Benzene1.0 7Benzo(a)pyrene0.01 8Boron1.0 mg/l 9Bromate10 Cadmium5.0 11Chromium50 12Copper2.0 mg/l 13Cyanide50 141,2-Dichloroethane3.0 15Epichlorohydrin Fluoride (a) fluoridated supplies 0.8 mg/l Fluoride (b) naturally occurring fluoride, not needing further fluoridation 1.5 mg/l No.ParameterValue (μg/l) 17 Lead – to 24/12/1325 Lead – from 25/12/ Mercury1.0 19Nickel20 Nitrate50 mg/l 21Nitrite0.5 mg/l 22Pesticides0.1 23Pesticides Total0.5 24PAH0.1 25Selenium10 26 Tetrachloroethene and Trichloroethene 10 27Trihalomethanes – Total100 28Vinyl chloride0.5 Table B Chemical Parameters No.ParameterValue (μg/l) 27 Trihalomethanes - Total100 Legislation

26 26 Ensure Quality (Regulation 4) No.ParameterValue 29Aluminium200 μg/l 30Ammonium0.3 mg/l 31Chloride250 mg/l 32Clostridium perfringensZero No./100ml 33Colour Acceptable to consumers & no abnormal change 34Conductivity o C 35Hydrogen Ion Concentration6.5 & Iron200 μg/l 37Manganese50 μg/l 38Odour Acceptable to consumers & no abnormal change No.ParameterValue 39Oxidisability5mg/lO 2 40Sulphate250 mg/l 41Sodium200 mg/l 42Taste Acceptable to consumers & no abnormal change 43Colony count 22 o C No abnormal change 44Coliform bacteriaZero no./100ml 45Total Organic Carbon (TOC) No abnormal change 46Turbidity Acceptable to consumers & no abnormal change Table C Indicator Parameters Legislation

27 27 Ensure Quality (Regulation 4) No.ParameterValue 29Aluminium200 μg/l 30Ammonium0.3 mg/l 31Chloride250 mg/l 32Clostridium perfringensZero No./100ml 33Colour Acceptable to consumers & no abnormal change 34Conductivity o C 35Hydrogen Ion Concentration6.5 & Iron200 μg/l 37Manganese50 μg/l 38Odour Acceptable to consumers & no abnormal change No.ParameterValue 39Oxidisability5mg/lO 2 40Sulphate250 mg/l 41Sodium200 mg/l 42Taste Acceptable to consumers & no abnormal change 43Colony count 22 o C No abnormal change 44Coliform bacteriaZero no./100ml 45Total Organic Carbon (TOC) No abnormal change 46Turbidity Acceptable to consumers & no abnormal change Table C Indicator Parameters No.ParameterValue 33Colour Acceptable to consumers & no abnormal change 38Odour 42Taste 46Turbidity Legislation

28 Quality Quantity Quality Quantity 28 Focus Shift

29 Factors Influencing Microbial Change in Water Distribution Systems 29 Quality Issues

30 30 Loss of Disinfection Residual Quality Issues

31 31 Loss of Disinfection Residual Quality Issues All water entering distribution systems should be disinfected Treated water should contain chlorine residual of 0.5mg/L for 30mins contact time prior to supply Residual should be monitored before entering distribution Maintain residual of at least 0.1 mg/L at the extremity of the network EPA Guidance on Chlorination

32 32 Loss of Disinfection Residual Quality Issues Rate of Loss Up to 50% lost during primary disinfection (first few hours) Rate of loss thereafter reduces significantly and depends on:- - Temperature - Reactivity of organic carbon in water - Reactivity of Pipe wall – wall demand Half life after primary disinfection can vary from several days to several weeks but can reduce to several hours with high demand.

33 33 Loss of Disinfection Residual Quality Issues Use chloramines for secondary disinfection – longer lasting Pipe flushing, relining or replacement to reduce wall demand Reduce residence times in storage. Install booster chlorination facilities Reduce total level of organic carbon in treatment process. Mitigation

34 34 Quality Issues

35 35 Quality Issues Reaction of chlorine with naturally occuring organic matter Most common by-products are Trihalomethanes (potential carcinogens) Amount of THM production depends on:- - pH - Temperature - Chlorine dose - Amount of organic precursor - Reaction time

36 36 Prevention Remove organic precursors during treatment Change disinfectant (Chloramines) Reduce water age in distribution system (quicker turnover) Quality Issues

37 37 Quality Issues

38 38 Quality Issues Contributing Factors Flow – Stagnant conditions promote tuberculation and pitting in iron pipes. Temp - Rate of corrosion increases with incresing temperature pH - Lower pH promotes corrosion. DO - Oxygen promotes corrsion of ferrous metal forming tubercules and red water TDS - Increases conductivity promoting electrochemicl corrosion Bacteria - Bacteria in bioflim can create local changes in pH and DO.

39 39 Quality Issues Indicator - Langelier Saturation Index LSI = pH - pH s LSI > 0 Water is supersaturated with respect to calcium carbonate (CaCO3) and scale forming may occur.

40 40 Quality Issues Control Make water less corrosive - pH adjustment most common (Typically 8.0 to 8.5). Lay down protective lining on pipe wall - pH adjustment or Phosphate addition Replace pipe with pipe less prone to corrosion.

41 41 Quality Issues

42 42 Quality Issues Promotion Growth depends on nutrient avalability (TOC) High temperatures (>15 o C) promote greater bacterial activity Corroded pipes support film development Low disinfecion residual Low / stagnant flow

43 43 Quality Issues Reduction Reduce nutrient avalability during treatment (reduce TOC) Optimise disinfectant dosage / booster chlorination Flushing Corrosion control Mains rehabilitation or replacement

44 44 Quality Issues

45 45 Quality Issues Backsiphoning Backflow when pressure in main drops (e.g. Surge, excessive flows, pipe bursts, flushing) Backpressure Backflow when pressure on contamonation side increases (e.g. pressurised heating/cooling systems, industrial systems.

46 46 Quality Issues

47 47

48 Water Conservation 48 Water Distribution Network Management and Leakage Control

49 49 Water Conservation

50 StageElementCentral Funding Level Stage 1Implementation of Water Management Systems 100% (records 90%) Stage 2Active Leakage Control100% limited Stage 3Rehabilitation90% Strategic Plans90% 50 Water Conservation

51 Dublin Regional Water Conservation Project Total Savings 7.9 Ml/day Pipe Rehabilitation Ml/day Pressure Management Ml/day DMA Optimisation/Metering- 3.4 Ml/day 51 Water Conservation

52 Asset Data Examples of Raw Data Held Customer demand (billing information) Customer complaints Customer meter locations Customer surveys Demand surveys Facilities failures Flow and pressure measurements Inspectors' site reports Mains and facilities record drawings Measured leakage and other non revenue water uses and wastage Meter maintenance/audits Number of shut valves and operations Network maintenance reports Network performance by location Records of repairs and rehabilitation Pipe sampling (e.g. cut outs) Staff training records Water quality samples by location Systems and processes used to collate and interpolate data Asset data support Burst records/deterioration models District Meter Area monitoring Distribution 0peration Maintenance Strategies Emergency plans Geographic Information Systems Health & Safety records Hydraulic, surge and water quality modelling Information and models from other utilities Job scheduling Leak management 52 Water Conservation

53 2 + 2 = = 8 x + y = ? Asset Data 53 Water Conservation

54 UFW = Water produced – Water Consumed Made up of:- Leakage Incorrect meter readings Illegal connections Illegal or unknown use Waste of water Taps left open Household losses Bad plumbing Tanks over flowing 54 Unaccounted For Water

55 Scenario 2: Reduce UFW by half 200m3/day 400m3/day 600m3/day 67% 17l/conn/hr 833l/km/hr Scenario 3: New Large Non- Domestic Usage 800m3/day 800m3/day 1,600m3/day 50% 33l/conn/hr 1,667l/km/hr Scheme AScenario 1: 20 km of mains 1000 properties AFW200m3/day UFW800m3/day Into Supply1,000m3/day UFW Expressions80% 33l/conn/hr 1,667l/km/hr Scheme AScenario 1: Scenario 2: Scenario 3: 20 km of mains Reduce UFW by half New Large Non- Domestic Usage 1000 properties AFW200m3/day 200m3/day 800m3/day UFW800m3/day 400m3/day 800m3/day Into Supply1,000m3/day 600m3/day 1,600m3/day UFW Expressions80% 67% 50% 33l/conn/hr 17l/conn/hr 33l/conn/hr 1,667l/km/hr 833l/km/hr 1,667l/km/hr 55 Unaccounted For Water

56 56 | 56 Leakage

57 57 | 57 Leakage

58 58 | 58 Leakage

59 59 | 59 Leakage

60 60 | 60 Leakage

61 Leakage Control 61 Leakage

62 Typical SRELL Target Leakage (m3/km/d) Euro NPV ('000) Value of water lost ALC Costs Total Costs BLL ELL Economic Level of Leakage (ELL):- 62 Leakage

63 63 Rehabilitation

64 Lead Common Services 64 Rehabilitation

65 65 Lead Common Services Rehabilitation

66 66 Replacing Lead Common Services Rehabilitation

67 Good data is key to sound investment decisions It is more cost effective to actively manage than to passively manage Need to manage Water Quality risks associated with the distribution network. 67 Key Message

68 Thank You Qs 68


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