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“Green” & Sustainable Infrastructure: A Water Treatment Perspective Michael R. Schock USEPA, ORD, NRMRL, WSWRD Cincinnati, OH Michael.

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Presentation on theme: "“Green” & Sustainable Infrastructure: A Water Treatment Perspective Michael R. Schock USEPA, ORD, NRMRL, WSWRD Cincinnati, OH Michael."— Presentation transcript:

1 “Green” & Sustainable Infrastructure: A Water Treatment Perspective Michael R. Schock USEPA, ORD, NRMRL, WSWRD Cincinnati, OH Michael R. Schock USEPA, ORD, NRMRL, WSWRD Cincinnati, OH

2 Why Do We Care about Plumbing? Human healthHuman health  Toxic contaminants MetalsMetals MicroorganismsMicroorganisms Organic leachatesOrganic leachates  Allergens Dermal irritants (eg. Ni)Dermal irritants (eg. Ni) BiofilmsBiofilms

3 Why Do We Care about Plumbing? Materials longevityMaterials longevity  Uniform corrosion (wears through)  Non-uniform corrosion pinhole leakspinhole leaks tuberculationtuberculation

4 Scale View of Drinking Water Distribution Municipal distribution networkMunicipal distribution network  Mains  Storage tanks/reservoirs Service linesService lines Premise plumbing systemPremise plumbing system  Cold (drinking/consumption)  Hot (human use)

5 “Premise Plumbing” After NRC-NAS Report 1 definitionAfter NRC-NAS Report 1 definition ResidentialResidential School/day careSchool/day care HospitalHospital Office buildingOffice building Manufacturing complexManufacturing complex 1 National Research Council, Alternatives for Premise Plumbing. Ch. 8 in: Drinking Water Distribution Systems: Assessing and Reducing Risk, pp National Academies Press, Washington, DC.

6 Typical Plumbing Materials: DS Old unlined ironOld unlined iron Asbestos-cementAsbestos-cement Cement mortar linings with seal coatCement mortar linings with seal coat  Bitumen  Epoxy PlasticsPlastics In-situ relined (rehabilitated)In-situ relined (rehabilitated)  Cement mortar  Epoxy  Plastic liners

7 Typical New Premise Plumbing Materials CopperCopper PlasticsPlastics Copper alloy componentsCopper alloy components  Traditional leaded brasses  New low-Pb alloys Stainless steelsStainless steels Plated materials (Ni, Cr)Plated materials (Ni, Cr) Soldered jointsSoldered joints

8 What Are Contamination Sources? PipesPipes FaucetsFaucets Flow control/shut-off valvesFlow control/shut-off valves MetersMeters Pressure regulatorsPressure regulators Backflow preventersBackflow preventers Storage tanksStorage tanks Biofilms growing in the aboveBiofilms growing in the above

9 Pipe Networks Are Not Inert!

10 Challenges of Water Conservation Creates conditions ofCreates conditions of  Higher metal exposure potential  Depletion of disinfection  Temperature conditions favorable for nitrification and other biofilm growth Problem extent function of:Problem extent function of:  Background water chemistry  Usage pattern  Spatial distribution of contamination sources

11 Example: Copper Levels and Stagnation

12 Current Plumbing Standards EPA does not have statutory authority to require non-contaminating materials not be used in drinking water systemsEPA does not have statutory authority to require non-contaminating materials not be used in drinking water systems SDWA has voluntary standardsSDWA has voluntary standards Widespread use of NSF/ANSI 61 in model plumbing codesWidespread use of NSF/ANSI 61 in model plumbing codes Enforcement erratic or non-existentEnforcement erratic or non-existent

13 More Problems Standards not robust enough to cover low-flow challengesStandards not robust enough to cover low-flow challenges Many materials are legal under the standards, but can still contaminate under many water chemistriesMany materials are legal under the standards, but can still contaminate under many water chemistries  Leaded brasses  Copper

14 DW Treatment Dilemma Water chemistry targets of corrosion control often conflict with ideal conditions for DBP controlWater chemistry targets of corrosion control often conflict with ideal conditions for DBP control Increasing levels of disinfectant to overcome high water age cause more DBPs to formIncreasing levels of disinfectant to overcome high water age cause more DBPs to form High dosages of corrosion inhibitors create high nutrient loads for wastewater treatment plantsHigh dosages of corrosion inhibitors create high nutrient loads for wastewater treatment plants Phosphate inhibitors are costly and sometimes in short supplyPhosphate inhibitors are costly and sometimes in short supply

15 Reasons to Avoid Supplemental Building Water Treatment Dangerous chemicalsDangerous chemicals Requires chemical feed or other mechanical equipment operationRequires chemical feed or other mechanical equipment operation Ongoing chemical/process costOngoing chemical/process cost Requires dosage and background chemistry monitoring to maintain proper conditionsRequires dosage and background chemistry monitoring to maintain proper conditions May require licensed operator and state or federal regulation as TNCWSMay require licensed operator and state or federal regulation as TNCWS Even POU devices at each tap for consumption require monitoring and replacementEven POU devices at each tap for consumption require monitoring and replacement

16 What We Think is “Green” Reduced use of non-renewable natural resourcesReduced use of non-renewable natural resources  Manufacture of plumbing materials  Municipal or supplemental DW treatment chemicals Does not cause unhealthy levels of contamination under intended usage conditionsDoes not cause unhealthy levels of contamination under intended usage conditions  Metals  Organics  Microbial

17 What We Think is “Green” Does not require supplemental treatmentDoes not require supplemental treatment  Entry point  Point of use Does not create environmental challenges with wasteDoes not create environmental challenges with waste  Reduces metal loadings to WWTPs  Reduces nutrient loadings to WWTPs  Plumbing materials amenable to recycling/reuse

18 “Green Infrastructure” New Opportunity for Achievable Objectives Prevent the potential for contamination in the first placePrevent the potential for contamination in the first place Dramatically reduce the extent of contaminationDramatically reduce the extent of contamination Simplify central water treatment to provide better overall protectionSimplify central water treatment to provide better overall protection  Metal contamination  Corrosion  Disinfection  Disinfection byproducts (carcinogens)


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