Water and Wastewater

2. Water and Wastewater • Water Quality Laws • Water Treatment • Wastewater Treatment

3. Clean Water Act • Goal is to “restore the chemical, physical and biological integrity of the nation’s waters”

4. Requires reduction of pollutants entering all surface water • Strict requirements for wastewater treatment plants • Control of non-point source pollution • Tighter controls on toxic pollutants

5. In 1948 Congress passed a bill to provide federal funds for constructing wastewater treatment facilities • The 1972 amendments made significant changes

6. Mandated that by 1983 the nation’s waterways should be fishable and swimmable • By 1995 discharges to waterways should be eliminated

7. Standards defining the levels of pollutants acceptable for discharge were called effluent limitations • These were used when issuing National Pollution Discharge Elimination System, NPDES, permits

8. In 1989 there were 50,000 industrial and 16,000 municipal facilities that had NPDES permits • SPDES permits are temporary discharge permits issued for short-term occurrences • Enforcement actions, including criminal action, are taken for noncompliance

9. The CWA provides for the EPA in conjunction with the Army Corp of Engineers to protect wetlands by limiting the discharge of dredged or fill material into surface waters • Estuaries are protected from activities such as landfilling, sewage outflow and industrial wastewater discharge

10. Safe Drinking Water Act • Written in 1974, amended in 1986 • Protects drinking water resources • Requires adherence to established drinking water standards • Protects underground sources including a wellhead protection program

11. Basic Required Activities • Establish and enforce Maximum Contaminant Levels MCL’s • Monitoring of contaminants • Filtration of water from surface water sources • Regulation of the use of lead materials in public water supply systems • Wellhead protection

12. National Drinking Water Regulations • Found in 40 CFR • Primary drinking water standard affecting public health • Secondary standards affect aesthetic qualities of public drinking water

13. Maximum Contaminant Levels • Based on an assumed human consumption of 2 liters per day • If monitoring for a contaminant is not feasible then treatment techniques must insure compliance

14. Primary MCLs • Arsenic • Barium • Chromium • Cadmium • Lead • Mercury • Nitrate • Selenium

15. Maximum Contaminant Level Goals MCLGs • Not enforceable health goals • The Reference Dose, RfD, is the amount of chemical a person can be exposed to without any adverse health effects • It is obtained from the NOAEL which is divided by an uncertainty factor • For carcinogens the MCLG is set at zero

16. Marine Protection, Research, and Sanctuaries Act (Title I) • Requires permits for ocean dumping which may limit the sites and times that dumping occurs • Radiological, chemical and biological warfare agents and radioactive wastes are prohibited from being dumped

17. The Army Corp of Engineers is responsible for permitting of dredged materials • The Coast Guard monitors activities • The EPA assesses penalties for violations

18. Sewage sludge, ash & solid waste dumping has not lessened over the years • It has been moved further off shore • Persistence of plastics disposed at sea continues to be a threat to wildlife

19. Water Treatment (for Drinking Water) • A water supply is evaluated on it’s quality, quantity and proximity to where it is needed • A water supply system includes (Figure 7-7): • supply source • storage facility • treatment facility • transmission lines • final distribution facilities

20. Treatment plants generally remove disease causing microorganisms, trace organic compounds, suspended solids, minerals causing hardness, and substances causing disagreeable color, taste and odor.

21. Consumptive use in the US is about 22 % • This means that the majority of the water supplied ends up as waste water • The average American uses more than 180 gallons a day

22. Waterborne Disease • Typhoid • Dysentery • Cholera • Infectious hepatitis • Amoebic dysentery • Giardiasis • Gastroenteritis • Cryptosporidiosis

23. Chemical Contaminants • Minerals dissolved from rocks and soil • Pesticides and herbicides • Leaking underground storage tanks • Industrial effluents • Seepage from septic systems • Wastewater treatment plants • Landfills

24. The water itself may be corrosive, leaching lead into the water supply • The water treatment process itself may introduce trihalomethanes, a by-product of the reaction of chlorine with organic materials and other chemical contaminants

25. Water may be treated to improve its color, odor and taste • Iron and manganese may be removed to prevent staining of clothes and plumbing fixtures • Fluoride is added to improve dental health

26. Physical Treatment(for Drinking Water) • Does not produce a new substance • Types of Treatment • Screening • Adsorption • Aeration • Flocculation (when coagulants used) • Sedimentation • Filtration (including membranes)

27. Chemical Treatment(for Drinking Water) • Results in the formation of new chemical substances • Type of Treatment • Coagulation (for better filtration) • Disinfection (fig. 7-15) • Water softening (ion exchange for Na) • Oxidation (via aeration or ozone)

28. Biological Treatment(for Drinking Water) • Use living organisms to bring about chemical change

29. Waste Water Treatment • Individual Systems – Septic Systems • Public/Municipal Treatment Systems • Primary Treatment • Secondary Treatment • Tertiary Treatment