Water and Wastewater Water Quality Laws Water Treatment Wastewater Treatment

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

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

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

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

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

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

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

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

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

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

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

Primary MCLs –Arsenic –Barium –Chromium –Cadmium –Lead –Mercury –Nitrate –Selenium

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

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

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

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

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

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

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

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

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

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

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

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)

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)

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

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