Transcript Document
Water Pollution G. Tyler Miller’s Living in the Environment 14th Edition Chapter 22 Key Concepts Types, sources, and effects of water pollutants Major pollution problems of surface water Major pollution problems of groundwater Reduction and prevention of water pollution Drinking water quality Types, Effects and Sources of Water Pollution Point sources Refer to Tables 22-1 and 22-2 p. 492 and 493 Nonpoint sources Fig. 22-3 p. 494 Water quality Point and Nonpoint Sources NONPOINT SOURCES Rural homes Cropland Urban streets Animal feedlot Suburban development POINT SOURCES Factory Wastewater treatment plant Fig. 22-4 p. 494 Pollution of Streams Oxygen sag curve Factors influencing recovery Fig. 22-5 p. 496 Pollution of Lakes Eutrophication Fig. 22-7 p. 499 Case Study: The Great Lakes Fig. 22-8 p. 500 Groundwater Pollution: Causes Low flow rates Few bacteria Low oxygen Cold temperatures Hazardous waste injection well Pesticides Coal strip mine runoff De-icing road salt Pumping well Waste lagoon Gasoline station Water pumping well Landfill Buried gasoline and solvent tank Cesspool septic tank Sewer Leakage from faulty casing Accidental spills Discharge Confined aquifer Groundwater flow Fig. 22-9 p. 502 Groundwater Pollution Prevention Monitor aquifers Find less hazardous substitutes Leak detection systems Strictly regulating hazardous waste disposal Store hazardous materials above ground Ocean Pollution Fig. 22-11 p. 504 Case Study: Chesapeake Bay Largest US estuary Relatively shallow Slow “flushing” action to Atlantic Major problems with dissolved O2 Fig. 22-13 p. 506 Oil Spills Sources: offshore wells, tankers, pipelines and storage tanks Effects: death of organisms, loss of animal insulation and buoyancy, smothering Significant economic impacts Mechanical cleanup methods: skimmers and blotters Chemical cleanup methods: coagulants and dispersing agents Solutions: Preventing and Reducing Surface Water Pollution Nonpoint Sources Point Sources Reduce runoff Clean Water Act Buffer zone vegetation Water Quality Act Reduce soil erosion Technological Approach: Septic Systems Require suitable soils and maintenance Fig. 22-15 p. 510 Technological Approach: Sewage Treatment Physical and biological treatment Fig. 22-16 p. 511 Technological Approach: Advanced (Tertiary) Sewage Treatment Uses physical and chemical processes Removes nitrate and phosphate Expensive Not widely used Technological Approach: Using Wetlands to Treat Sewage Fig. 22-18 p. 513 Drinking Water Quality Purification of urban drinking water Protection from terrorism Purification of rural drinking water Safe Drinking Water Act Maximum contaminant levels (MCLs) Bottled water