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Water Services Network Management

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

  2. 2 Mizen Footbridge

  3. 3 ?

  4. 4

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

  6. 6 World Water Day – 22nd March

  7. A Brief History of Cork City’s Water Supply 1762 - Cork Pipe Water Company Established Timber distribution pipes, 20ft long – 2 ½” to 3” ø 1856 - Cork Bridges, Waterworks and Improvement Act 1857 - Cast iron mains introduced – network extended. 1879 – Filter tunnel constructed 1911 - “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 1940’s - new high level reservoir built as an unemployment relief scheme 1956 – New filters and sedimentation plant 7

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

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

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

  11. Network Planning 11 Distribution Input (DI) 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 Accounted for Water (AFW) Measured or assessed lergitimate water use Unaccounted for Water (UFW) = DI - AFW Demand Assesment • Current Demand - Water Audit Demand Assessment

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

  13. Network Planning 13 Demand Assesment • Current Demand • Demand Management • Future Demand Demand Assessment • 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.

  14. Network Planning 14 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. Collect Network Asset Data

  15. Network Planning 15 0 - 5 Yrs 5 - 10 Yrs 10 - 15 Yrs 15 - 20 Yrs 20 - 25 Yrs Demand / Capacity Projected Demand Range Capacity Shortfall Rated Asset Capacity Expected Time Range of Deficit Design Horizon Asset Capacity Assessment Capacity Assessment

  16. Network Planning 16 0 - 5 Yrs 5 - 10 Yrs 10 - 15 Yrs 15 - 20 Yrs 20 - 25 Yrs Increased Asset Capacity Demand / Capacity Rated Asset Capacity Expected Time Range of Deficit Design Horizon Asset Capacity Assessment Capacity Assessment

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

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

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

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

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

  22. Legislation 22 Ensure Quality (Regulation 4) Table A Microbiological Parameters

  23. Legislation No. Parameter Value (μg/l) 3 Acrylamide 0.10 No. Parameter Value (μg/l) 4 Antimony 5.0 17 Lead – to 24/12/13 25 5 Arsenic 10 6 Benzene 1.0 Lead – from 25/12/13 10 7 Benzo(a)pyrene 0.01 18 Mercury 1.0 8 Boron 1.0 mg/l 9 Bromate 10 19 Nickel 20 10 Cadmium 5.0 20 Nitrate 50 mg/l 11 Chromium 50 21 Nitrite 0.5 mg/l 12 Copper 2.0 mg/l 22 Pesticides 0.1 13 Cyanide 50 23 Pesticides Total 0.5 14 1,2-Dichloroethane 3.0 24 PAH 0.1 15 Epichlorohydrin 0.1 25 Selenium 10 16 Fluoride (a) fluoridated supplies 0.8 mg/l 26 Tetrachloroethene and Trichloroethene 10 Fluoride (b) naturally occurring fluoride, not needing further fluoridation 1.5 mg/l 27 Trihalomethanes – Total 100 28 Vinyl chloride 0.5 23 Table B Chemical Parameters Ensure Quality (Regulation 4)

  24. Legislation No. No. Parameter Parameter Value (μg/l) Value (μg/l) 3 Acrylamide 0.10 17 Lead – until 24th December 2013 25 No. Parameter Value (μg/l) 4 Antimony 5.0 Lead – from 25th December 2013 10 17 Lead – to 24/12/13 25 5 Arsenic 10 6 Benzene 1.0 Lead – from 25/12/13 10 7 Benzo(a)pyrene 0.01 18 Mercury 1.0 8 Boron 1.0 mg/l 9 Bromate 10 19 Nickel 20 10 Cadmium 5.0 20 Nitrate 50 mg/l 11 Chromium 50 21 Nitrite 0.5 mg/l 12 Copper 2.0 mg/l 22 Pesticides 0.1 13 Cyanide 50 23 Pesticides Total 0.5 14 1,2-Dichloroethane 3.0 24 PAH 0.1 15 Epichlorohydrin 0.1 25 Selenium 10 16 Fluoride (a) fluoridated supplies 0.8 mg/l 26 Tetrachloroethene and Trichloroethene 10 Fluoride (b) naturally occurring fluoride, not needing further fluoridation 1.5 mg/l 27 Trihalomethanes – Total 100 28 Vinyl chloride 0.5 24 Table B Chemical Parameters Ensure Quality (Regulation 4)

  25. Legislation No. Parameter Value (μg/l) 3 Acrylamide 0.10 No. Parameter Value (μg/l) 4 Antimony 5.0 17 Lead – to 24/12/13 25 5 Arsenic 10 6 Benzene 1.0 Lead – from 25/12/13 10 7 Benzo(a)pyrene 0.01 18 Mercury 1.0 8 Boron 1.0 mg/l 9 Bromate 10 19 Nickel 20 10 Cadmium 5.0 20 Nitrate 50 mg/l 11 Chromium 50 21 Nitrite 0.5 mg/l 12 Copper 2.0 mg/l 22 Pesticides 0.1 13 Cyanide 50 23 Pesticides Total 0.5 14 1,2-Dichloroethane 3.0 24 PAH 0.1 15 Epichlorohydrin 0.1 25 Selenium 10 16 Fluoride (a) fluoridated supplies 0.8 mg/l 26 Tetrachloroethene and Trichloroethene 10 Fluoride (b) naturally occurring fluoride, not needing further fluoridation 1.5 mg/l 27 Trihalomethanes – Total 100 28 Vinyl chloride 0.5 25 Table B Chemical Parameters Ensure Quality (Regulation 4) No. Parameter Value (μg/l) Trihalomethanes - Total 100 27

  26. Legislation No. Parameter Value No. Parameter Value 29 Aluminium 200 μg/l 39 Oxidisability 5mg/lO2 30 Ammonium 0.3 mg/l 40 Sulphate 250 mg/l 31 Chloride 250 mg/l 41 Sodium 200 mg/l 32 Clostridium perfringens Zero No./100ml 42 Taste Acceptable to consumers & no abnormal change 33 Colour Acceptable to consumers & no abnormal change 43 Colony count 22oC No abnormal change 34 Conductivity 2500 μS/cm @ 20oC 44 Coliform bacteria Zero no./100ml 35 Hydrogen Ion Concentration ≥6.5 & ≤9.5 45 Total Organic Carbon (TOC) No abnormal change 36 Iron 200 μg/l 37 Manganese 50 μg/l 46 Turbidity Acceptable to consumers & no abnormal change 38 Odour Acceptable to consumers & no abnormal change 26 Table C Indicator Parameters Ensure Quality (Regulation 4)

  27. Legislation No. Parameter Value No. Parameter Value 29 Aluminium 200 μg/l No. Parameter Value 39 Oxidisability 5mg/lO2 30 Ammonium 0.3 mg/l 40 Sulphate 250 mg/l 31 Chloride 250 mg/l 33 Colour Acceptable to consumers & no abnormal change 41 Sodium 200 mg/l 32 Clostridium perfringens Zero No./100ml 42 Taste Acceptable to consumers & no abnormal change 33 Colour Acceptable to consumers & no abnormal change 38 Odour 42 Taste 43 Colony count 22oC No abnormal change 34 Conductivity 2500 μS/cm @ 20oC 44 Coliform bacteria Zero no./100ml 46 Turbidity 35 Hydrogen Ion Concentration ≥6.5 & ≤9.5 45 Total Organic Carbon (TOC) No abnormal change 36 Iron 200 μg/l 37 Manganese 50 μg/l 46 Turbidity Acceptable to consumers & no abnormal change 38 Odour Acceptable to consumers & no abnormal change 27 Table C Indicator Parameters Ensure Quality (Regulation 4)

  28. Focus Shift 28 Quality Quantity Quality Quantity

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

  30. Quality Issues 30 • Loss of Disinfection Residual

  31. Quality Issues 31 EPA Guidance on Chlorination • 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 • Loss of Disinfection Residual

  32. Quality Issues 32 • Loss of Disinfection Residual 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. Quality Issues 33 Mitigation • 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. • Loss of Disinfection Residual

  34. Quality Issues 34 • Loss of Disinfection Residual • Growth of Disinfection By-products

  35. Quality Issues 35 • Loss of Disinfection Residual • Growth of Disinfection By-products • Reactionof 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. Quality Issues 36 • Loss of Disinfection Residual • Growth of Disinfection By-products Prevention • Remove organic precursors during treatment • Change disinfectant (Chloramines) • Reduce water age in distribution system (quicker turnover)

  37. Quality Issues 37 • Loss of Disinfection Residual • Growth of Disinfection By-products • Corrosion / dissolution

  38. Quality Issues 38 • Loss of Disinfection Residual • Growth of Disinfection By-products • Corrosion / dissolution 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. Quality Issues 39 • Loss of Disinfection Residual • Growth of Disinfection By-products • Corrosion / dissolution Indicator - Langelier Saturation Index LSI = pH - pHs LSI > 0 Water is supersaturated with respect to calcium carbonate (CaCO3) and scale forming may occur.

  40. Quality Issues 40 • Loss of Disinfection Residual • Growth of Disinfection By-products • Corrosion / dissolution 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. Quality Issues 41 • Loss of Disinfection Residual • Growth of Disinfection By-products • Corrosion / dissolution • Growth of Biofilms

  42. Quality Issues 42 Promotion • Growth depends on nutrient avalability (TOC) • High temperatures (>15oC) promote greater bacterial activity • Corroded pipes support film development • Low disinfecion residual • Low / stagnant flow • Loss of Disinfection Residual • Growth of Disinfection By-products • Corrosion / dissolution • Growth of Biofilms

  43. Quality Issues 43 Reduction • Reduce nutrient avalability during treatment (reduce TOC) • Optimise disinfectant dosage / booster chlorination • Flushing • Corrosion control • Mains rehabilitation or replacement • Loss of Disinfection Residual • Growth of Disinfection By-products • Corrosion / dissolution • Growth of Biofilms

  44. Quality Issues 44 • Loss of Disinfection Residual • Growth of Dinisfection By-products • Corrosion / dissolution • Growth of Biofilms • Cross connections and backflow

  45. Quality Issues 45 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. • Loss of Disinfection Residual • Growth of Dinisfection By-products • Corrosion / dissolution • Growth of Biofilms • Cross connections and backflow

  46. Quality Issues 46 • Loss of Disinfection Residual • Growth of Dinisfection By-products • Corrosion / dissolution • Growth of Biofilms • Cross connections and backflow • Stagnation – Dead Ends

  47. Quality Issues • Loss of Disinfection Residual • Growth of Dinisfection By-products • Corrosion / dissolution • Growth of Biofilms • Cross connections and backflow • Stagnation – Dead Ends • Milky Water 47

  48. Water Conservation 48 • Water Distribution Network Management and Leakage Control

  49. Water Conservation 49 • Water Distribution Network Management and Leakage Control • Passive V’s Active

  50. Water Conservation 50