环境概论Introduction to Environment,董方 土木与水利工程学院,第9讲 Water Pollution,Types of Water Pollution,Sewage,Types of Water Pollution,Effect of sewage on dissolved oxygen and biological oxygen demand,氧垂曲线,Types of Water Pollution,Clean Zone,Decomposition Zone,Septic Zone,Recovery Zone,Clean Zone,Normal clean water organisms (trout, perch, bass, mayfly, stonefly),Trash fish (carp, gar, leeches),Fish absent, fungi, sludge worms, bacteria (anaerobic),Trash fish (carp, gar, leeches),Normal clean water organisms (trout, perch, bass, mayfly, stonefly),8 ppm,Dissolved oxygen (ppm),Biological oxygen demand,8 ppm,Types of organisms,4,Types of Water Pollution,Eutrophication: An Enrichment Problem,Oligotrophic lake 贫营养湖泊,5,Types of Water Pollution,Eutrophication: An Enrichment Problem,Eutrophic lake 富营养湖泊,6,2010年6月22日，安徽巢湖东半湖双桥河一带拍摄的大面积蓝藻。,2010年6月22日，安徽巢湖东半湖双桥河一带拍摄的大面积蓝藻。,Discharge of untreated municipal sewage (nitrates and phosphates),Nitrogen compounds produced by cars and factories,Discharge of treated municipal sewage (primary and secondary treatment: nitrates and phosphates),Discharge of detergents ( phosphates),Manure runoff from feedlots (nitrates, phosphates, ammonia),Dissolving of nitrogen oxides (from internal combustion engines and furnaces),Runoff and erosion (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,Inorganic fertilizer runoff (nitrates and phosphates),9,10,Types of Water Pollution,Disease-Causing Agents（Monitoring for Sewage）,Fecal coliform test 粪大肠菌群实验,11,Types of Water Pollution,Sediment Pollution,Low sediment load,12,Types of Water Pollution,Sediment Pollution,High sediment load,13,Water Quality Today,Point source pollution (e.g., cyanide spill 氰化物泄漏) Nonpoint source pollution (e.g., fertilizer runoff from agriculture fields) Water Pollution from Agriculture 72% of water pollution in rivers attributed to agriculture Chemical pesticides may leach into soil and then into water.,14,Water Quality Today,Municipal Water Pollution,Water Quality Today,Industrial Wastes in Water Problems depend upon industry Food processing high BOD Paper mills toxic compounds aerobic bacteria consume organic matter Leave dissolved inorganics, NO3, PO4, etc.,44,Sewage Treatment,Tertiary Filters most dissolved inorganics and remaining dissolved organic compounds Can be done biologically in wetlands Natural Artificial,45,Improving Water Quality,Municipal Sewage Treatment,Effectiveness of primary, secondary, and tertiary sewage treatment,46,Improving Water Quality,Municipal Sewage Treatment Major problem associated with wastewater treatment is disposal of sludge 污泥处理 Can be used as fertilizer, but there may be health risks (e.g., heavy metal poisoning) Used to be dumped in ocean, that is now banned Currently, most dumped in landfills 填埋,47,Improving Water Quality,Individual Septic Systems,Septic tank化粪池,48,Improving Water Quality,Individual Septic Systems,Drain field,49,Laws Controlling Water Pollution,Safe Drinking Water Act set the maximum contaminant level for drinking water Clean Water Act pertained to improving quality of rivers, lakes, aquifers, estuaries, and coastal waters,50,Laws Controlling Water Pollution,Case-in-Point: Water Pollution in the Great Lakes,51,Laws Controlling Water Pollution,Laws That Protect Groundwater Safe Drinking Water Act Resource, Conservation, and Recovery Act,52,