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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.

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Presentation on theme: "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."— Presentation transcript:

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? $$ Cost $$ Improvement

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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