Human Waste Disposal More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water. More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water. Natural Processes Natural Processes –In many areas, outdoor urination and defecation is the norm. When population densities are low, natural processes can quickly eliminate waste. When population densities are low, natural processes can quickly eliminate waste.

Municipal Sewage Treatment Primary Treatment - Physical (mechanical) separation of large solids from the waste stream. Primary Treatment - Physical (mechanical) separation of large solids from the waste stream. (uses sticks, grit(stones),screens & filters = sludge settles out) Removes 60% suspended solids & 30% organic waste (ex. Bacteria) Does NOT remove phosphaste, nitrate, pesticides, salts, radioisotopes

Secondary Treatment - Biological degradation of dissolved organic compounds. (aerobic bacteria filter out 90% of biodegradable organic waste) Secondary Treatment - Biological degradation of dissolved organic compounds. (aerobic bacteria filter out 90% of biodegradable organic waste) –Effluent from primary treatment transferred into trickling bed, or aeration tank or to activated sludge treatment. –Chlorine disinfection tank kills bacteria & removes discoloration Sludge – is either incinerated, put in land fills, or used as fertilizers

Municipal Sewage Treatment Tertiary Treatment (advanced treatment) – special chemical and physical treatment that remove specific pollutants after primary & secondary treatment. Tertiary Treatment (advanced treatment) – special chemical and physical treatment that remove specific pollutants after primary & secondary treatment. –Chemicals, or natural wetlands. Growing interest in membrane technology – reverse osmosis, Ultrafiltration (too $$$) Wastewater Gardens – artificial wetland system used to treat small amounts of sewage

Municipal Sewage Treatment

Areas of Progress In 1998, EPA switched regulatory approaches. Rather than issue standards on a site by site approach, the focus is now on watershed-level monitoring and protection. In 1998, EPA switched regulatory approaches. Rather than issue standards on a site by site approach, the focus is now on watershed-level monitoring and protection. –States are required to identify waters not meeting water quality goals and develop total maximum daily loads for each pollutant and each listed water body.

WATER LEGISLATION Clean Water Act (1972) Clean Water Act (1972) –Goal was to return all US surface waters to “fishable and swimmable” conditions. For Point Sources, Discharge Permits and Best Practicable Control Technology are required. For Point Sources, Discharge Permits and Best Practicable Control Technology are required. –Set zero discharge for 126 priority toxic pollutants.

Clean Water Act (1972/1977) Addressed regulations for point source pollutants, non-point pollutants, & municipal waste treatment plants Addressed regulations for point source pollutants, non-point pollutants, & municipal waste treatment plants Areas of Contention Areas of Contention –Draining or Filling of Wetlands Many consider this taking of private land. Many consider this taking of private land. –Un-funded Mandates State or local governments must spend monies not repaid by Congress. State or local governments must spend monies not repaid by Congress.

Other Water Legislation Safe Drinking Water Act (1974) – established max. containment levels for pollutants Safe Drinking Water Act (1974) – established max. containment levels for pollutants CERCLA (1980) – see below CERCLA (1980) – see below Great Lakes Water Quality Agreement (1972) Great Lakes Water Quality Agreement (1972) London Dumping Convention (1990) London Dumping Convention (1990) The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, was enacted by Congress on December 11, This law created a tax on the chemical and petroleum industries and provided broad Federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment. Over five years, $1.6 billion was collected and the tax went to a trust fund for cleaning up abandoned or uncontrolled hazardous waste sites. CERCLA: