Water

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  • http://www.ust.hk/~webpepa/pepa/ways_of_protection/fresh_water_use.JPG
  • Use of water resources Since 1950, the global rate of water use has increased almost 5 fold, to meet the need of growing population.  Averaged globally, about 69% of the fresh water resource is used to irrigate 18% of the world's cropland. However, much irrigation is wasted; 70-80% of the water either evaporates or seeps into the ground before reaching crops. Another main use of water is energy production and industrial processing, making up about 23% of the total. Let see use of water in different countries, U.S. and China: http://www.ust.hk/~webpepa/pepa/ways_of_protection/water_general.html
  • comes from many diffuse sources. caused by rainfall or snowmelt moving over and through the ground As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water. These pollutants include: Excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas; Oil, grease, and toxic chemicals from urban runoff and energy production; Sediment from improperly managed construction sites, crop and forest lands, and eroding streambanks; Salt from irrigation practices and acid drainage from abandoned mines; Bacteria and nutrients from livestock, pet wastes, and faulty septicsystems; Atmospheric deposition and hydromodification are also sources of nonpoint source pollution http://www.epa.gov/owow/nps/qa.html http://www.protectingwater.com/
  • http://www.youngreporters.org/IMG/gif/acidrain.gif
  • http://www.k12.hi.us/~cnagasak/manoabeauty/Images/Storm%20Drain%20Run-off/oil%20spills.jpg
  • http://www.ust.hk/~webpepa/pepa/ways_of_protection/water_general.html
  • http://www.ust.hk/~webpepa/pepa/ways_of_protection/water_general.html
  • biological process in which aerobic bacteria are used to remove up to 90% of biodegradable wastes. Air are added to the tank to facilitate degradation of wastes by micro-organisms. The water then goes to a sedimentation tank where most of the suspended solids and micro-organisms settle out as sludge. http://www.ust.hk/~webpepa/pepa/ways_of_protection/water_general.html
  • http://www.ust.hk/~webpepa/pepa/ways_of_protection/water_general.html
  • Water

    1. 1. OUR WATER RESOURCES
    2. 2. Water Supplies
    3. 3. Water Consumption
    4. 4. Water Pollution Sources • Non-point sources • Point sources
    5. 5. Non-point Sources of Pollution • As water from rainfall and snowmelt flows over and through the landscape, it picks up and carries contaminants from many different sources. • The polluted water ends up in streams, lakes and the ocean. • Water also carries pollutants into underground drinking water as it soaks into the ground.
    6. 6. Non-point Source
    7. 7. Excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas
    8. 8. Acid Rain
    9. 9. Point Sources of Pollution • Occur when harmful substances are emitted directly into a body of water.
    10. 10. The main sources of pollutants are sewage and industrial wastes. • Pathogens - Disease causing agents, e.g. bacteria and virus • Organic wastes, e.g. animal wastes • Soluble inorganic chemicals -- acids, salts and heavy metals • Suspended particles which make the water looks cloudy and turbid • Heat - Hot water released by industrial and power plants • Radioactive wastes
    11. 11. Non-native species are also considered biological pollutants.
    12. 12. INCREASED WASTES INCREASED POPULATION OF BACTERIA THAT DECOMPOSE WASTE INCREASED DEMAND FOR OXYGEN DEATH OF AQUATIC ORGANISMS INCREASED NUTRIENTS ALGAL BLOOMINCREASED WASTES INCREASED POPULATION OF BACTERIA THAT DECOMPOSE WASTE INCREASED DEMAND FOR OXYGEN DEATH OF AQUATIC ORGANISMS
    13. 13. Eutrophication
    14. 14. Diarrhea
    15. 15. Minamata Disease – mercury poisoning
    16. 16. SEWAGE TREATMENT
    17. 17. 1. Primary Sewage Treatment • Filtration of debris and suspended solids
    18. 18. 2. Secondary Sewage Treatment • Bacteria are used to remove up to 90% of biodegradable wastes
    19. 19. 3. Advanced or Tertiary Sewage Treatment • a series of specialized chemical and physical processes that remove specific pollutants left in the water after the previous treatments
    20. 20. Tertiary Treatment • Charcoal Filtration • Reverse Osmosis • Chlorination • Ozone treatment
    21. 21. • Water treatment requires the use of ENERGY. • We can run out of energy and therefore… • We can run out of clean water.
    22. 22. "When the well is dry, we know the worth of water". - Benjamin Franklin, Poor Richard's Almanac

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