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Chapter 16

Chapter 16. The Water Issue Cells in all living organisms are 60% water Water has number of useful properties Molecules stick together Great ability to separate other molecules Heats and cools slower than most substances Can be used to dissolve transport wastes

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Chapter 16

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  1. Chapter 16 The Water Issue • Cells in all living organisms are 60% water • Water has number of useful properties • Molecules stick together • Great ability to separate other molecules • Heats and cools slower than most substances • Can be used to dissolve transport wastes • However needs to be clean for us to drink it • 97% of Water is in oceans—saltwater • 3% is Freshwater • 1.9% in ice and glaciers • 0.5% in groundwater • 0.02% in rivers and lakes • 0.01% in soil

  2. Chapter 16 • Potable water—unpolluted freshwater that is of sufficient quality to drink • Some areas of world will exhaust water supplies in future • Water Pollution on a global scale renders 1.4 billion people without access to safe drinking water • Water Quality remains an issue in US

  3. Chapter 16 Hydrologic Cycle • Major processes are evaporation and condensation. • Evaporation is changing liquid to gas • Condensation is gas to liquid • Evapotranspiration is evaporation of moisture from leaves after plants have pulled moisture from ground • Solar Energy drives the process

  4. Chapter 16 Human Influences on Cycle • Irrigation/Cooling water from power plants increase evaporation • Removing vegetation increases runoff and decreases infiltration • Impervious cover increases this effect • Flooding increases with imperviousness • Creeks cease to flow in urban areas • Overuse of water resources is same as mining if use is greater than recharge/recovery • Surface water and ground water

  5. Chapter 16 • Use versus Consumption of water • Use (Non-Consumptive) • lake-plant-you-toilet-wwtp-lake • Stays in local water cycle, used but not consumed • Consumption • Lake-pump-field-evaporation-condensation • Removed from local cycle • Rain falls elsewhere

  6. Chapter 16 • Water Use by Category • Domestic • 90% provided by municipalities • Water is treated/disinfected • Use for drinking/bathing/washing/toilets/lawns • 70% non-consumptive 30% consumption • Agriculture • Irrigation for fields 80% of consumption in N. Amer • Number of methods • Can use lots of energy for pumping • Industry • 90% of water is non-consumptive use • Use-treat-discharge • Similar quantity but not necessarily quality

  7. Chapter 16 • In Stream Use • Non-Consumptive • Hydroelectric • Recreation • Navigation • May negatively effect waterway because of changes in direction, time, volume of flow • Cold water releases from dams

  8. Chapter 16 • Kinds and Sources of Water Pollution • Toxics • Kill organisms • Water unfit for consumption • Bio-accumulation • Organic matter • Broken down by microbes • Use up DO • BOD • Taste and odors • Pathogens • Disease causing organisms • Various bacteria • others

  9. Chapter 16 • Nutrients • Nitrogen and phosphorus • Increase growth • Eutrophication • DO • Physical Particles • Sediment • Destroy habitat • Water clarity • Abrasive • Transport

  10. Chapter 16 • How clean is clean? • Cannot eliminate all pollution • Law of Diminishing Returns? Improvement $$ Cost $$

  11. Chapter 16 Sources of Pollution • Point Sources • Readily identifiable • Discharge pipes • Non-Point Source • Diffuse sources • Much more difficult to ID and control • Most point sources are identified and regulated. • Non-Point sources remain a difficult issue to address

  12. Chapter 16 • Domestic Water Pollution • Storm water • Industrial waste • Home and commercial waste • Agricultural Water Pollution • Crops • CAFOs • Industrial Water Pollution • Easy to ID, well regulated, most under permits • WWTP-- in house or use city’s • Mining

  13. Chapter 16 • Thermal Water Pollution • Use lake/river/ocean water to cool • Can affect organisms • Marine Oil Pollution • Exxon Valdez spilled 11 million gallons • Much more is released by less visible sources • 2/3 of releases come from • Runoff from streets • Improper disposal • Routine handling

  14. Chapter 16 Waste Water Treatment • Primary • Physical process • Remove larger particles with screens • Smaller particles allowed to settle • Still lots of organics • Secondary • Biological process • Uses water from primary and adds DO and organisms—eat organics and fall out • Activated sludge

  15. Chapter 16 • Sludge Disposal • Ocean dumping • Land application • Composting • Drying • Incineration • Landfilling • Disinfection • Chlorination followed by dechlorination • Can also use UV light

  16. Chapter 16 • Tertiary Treatment • Removes dissolved pollutants • Used for nutrients • Techniques • Wetlands • Cropland, golf courses, etc • Aquatic greenhouses • In US most WWTP are at least Secondary plants- • Developing Countries?

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