Water and Wastewater Water Quality Laws Water Treatment Wastewater Treatment.

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