Living in the Environment Water Pollution G. Tyler Miller’s Living in the Environment 12th Edition Chapter 19 Dr. Richard Clements Chattanooga State Technical Community College

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 and Sources of Water Pollution Point sources Refer to Tables 19-1 and 19-2 p. 477 and 478 Nonpoint sources Water Quality Good 8-9 Do (ppm) at 20˚C Slightly polluted Moderately Heavily Gravely 6.7-8 4.5-6.7 Below 4.5 Below 4 Biological oxygen demand Water quality Fig. 19.2, p. 478

Time of distance downstream Pollution of Streams Oxygen sag curve Factors influencing recovery Clean Zone Decomposition Zone Septic Zone Recovery Zone Normal clean water organisms (Trout, perch, bass, mayfly, stonefly) Trash fish (carp, gar, Leeches) Fish absent, fungi, Sludge worms, bacteria (anaerobic) 8 ppm Dissolved oxygen Biological oxygen demand Oxygen sag 2 ppm Concentration Types of organisms Time of distance downstream Direction of flow Point of waste or heat discharge Fig. 19.3, p. 479

Pollution of Lakes Eutrophication Slow turnover Thermal stratification Discharge of untreated municipal sewage (nitrates and phosphates) Nitrogen compounds produced by cars and factories Discharge of treated (primary and secondary treatment: nitrates and phosphates) Discharge of detergents ( phosphates) Natural runoff (nitrates and phosphates Manure runoff From feedlots Phosphates, ammonia) Dissolving of nitrogen oxides (from internal combustion engines and furnaces) Runoff and erosion (from from cultivation, mining, construction, and poor land use) Runoff from streets, lawns, and construction lots (nitrates and phosphates) Lake ecosystem nutrient overload and breakdown of chemical cycling Slow turnover Thermal stratification Fig. 19.5, p. 482

Case Study: The Great Lakes Great Lakes drainage basin Most polluted areas, according to the Great Lakes Water Quality Board “Hot spots” of toxic concentrations in water and sediments Eutrophic areas CANADA WISCONSIN MINNESOTA IOWA ILLINOIS INDIANA OHIO PENNSYLVANIA NEW YORK MICHIGAN Nipigon Bay Thunder Bay Silver Bay St. Louis R. Jackfish Bay St. Mary’s R. Spanish R. Penetary Bay Sturgeon Bay Saginaw Bay Saginaw R. System St. Clair R. Detroit R. Rouge R. Raisin R. Maumee R. Black R. Rocky R. Cuyahoga R. Ashtabula R. Thames R. Grand R. Niagara Falls Niagara R. Buffalo R. St. Lawrence R. Fig. 19.7, p. 484

Groundwater Pollution: Sources Low flow rates Cold temperatures Waste lagoon, pond, or basin Mining site Pumping well Water pumping Sewer Cesspoll, septic tank Hazardous waste injection Buried gasoline and solvent tanks Landfill Road salt Unconfined freshwater aquifer Confined freshwater aquifer Confined aquifer Discharge Leakage from faulty casing Groundwater Groundwater flow Few bacteria Fig. 19.9, p. 487

Groundwater Pollution Prevention Monitoring aquifers Leak detection systems Strictly regulating hazardous waste disposal Storing hazardous materials above ground

Ocean Pollution Fig. 19.11, p. 489 Industry Nitrogen oxides from autos and smokestacks; toxic chemicals, and heavy metals in effluents flow into bays and estuaries. Cities Toxic metals and oil from streets and parking lots pollute waters; sewage adds nitrogen and phosphorus. Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds and close beaches; runoff of fertilization from lawns adds nitrogen and phosphorus. Construction sites Sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight. Farms Run off of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus. Red tides Excess nitrogen causes explosive growth of toxic microscopic algae, poisoning fish and marine mammals. Closed shellfish beds Closed beach Oxygen-depleted zone Toxic sediments Chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders. Healthy zone Clear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish. Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat. Fig. 19.11, p. 489

Case Study: Chesapeake Bay Drainage basin No oxygen Low concentrations of oxygen PENNSYLVANIA NEW YORK WEST VIRGINIA MARYLAND DELAWARE NEW JERSEY ATLANTIC OCEAN Cooperstown Harrisburg Baltimore Washington Richmond Norfolk Chesapeake Bay Largest US estuary Relatively shallow Slow “flushing” action to Atlantic Major problems with dissolved O2 Fig. 19.13, p. 490

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 Household wastewater Perforated pipe Distribution box (optional) Septic tank Manhole (for cleanout) Drain field Vent pipe Nonperforated Gravel or crushed stone Fig. 19.14, p. 494

Technological Approach: Sewage Treatment Mechanical and biological treatment Raw sewage from sewers Bar screen Grit chamber Settling tank Aeration tank Chlorine disinfection tank Sludge Sludge digester Activated sludge Air pump (kills bacteria) To river, lake, or ocean Sludge drying bed Disposed of in landfill or ocean or applied to cropland, pasture, or rangeland Primary Secondary Fig. 19.15, p. 494

Technological Approach: Advanced Sewage Treatment Removes specific pollutants Effluent from Secondary treatment Alum flocculation plus sediments Activated carbon Desalination (electrodialysis or reverse osmosis) Nitrate removal Specialized compound (DDT, etc.) 98% of suspended solids 90% of phosphates dissolved organics Most of dissolved salts Recycled to land for irrigation and fertilization To rivers, lakes, streams, oceans, reservoirs, or industries Fig. 19.16, p. 495

Technological Approach: Using Wetlands to Treat Sewage (1) Raw sewage drains by gravity into the first pool and flows through a long perforated PVC pipe into a bed of limestone gravel. (3) Wastewater flows through another perforated pipe into a second pool, where the same process is repeated. (2) Microbes in the limestone gravel break down the sewage into chemicals, that can be absorbed by the plant roots, and the gravel absorbs phosphorus. (4) Treated water flowing from the second pool is nearly free of bacteria and plant nutrients. Treated water can be recycled for irrigation and flushing toilets. 45 centimeter layer of limestone gravel coated with decomposing bacteria First concrete pool Second concrete pool Sewage Wetland type plants Treated water Fig. 19.17, p. 497

Drinking Water Quality 10 to 20 percent Greater than 20 percent Not tested Contaminated Probability Bottled water Safe Drinking Water Act Maximum contaminant levels Fig. 19.10, p. 488