Water Pollution and Its Prevention

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Chapter 18

• Water Pollution and Its Prevention

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Water Pollution
Categories
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Water Pollution Sources
Water pollution results from pathogens, organic
waste, chemicals, sediments, and nutrients
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Eutrophication Impacts
As nutrients are added to a water body, more
algae grow reducing light levels and killing
submerged vegetation. As bacteria consume dead
algae, oxygen levels drop in the lake killing
fish, which have also lost nesting sites
(vegetation).
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Eutrophication Combating It

• Symptoms
• chemical treatments
• aeration
• harvesting aquatic weeds
• drawing water down
• Causes
• reducing inputs of nutrients and sediment
• identify source
• determine allowable inputs from source

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Eutrophication Best Management Practices

• Practices to minimize
• erosion
• runoff
• leaching

• Includes
• conservation tillage
• contour farming
• IPM
• buffer strips
• proper road building

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Sewage Treatment Preliminary, Primary, and
Secondary
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Sewage Treatment Biological Nutrient Removal
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Sewage Treatment Sludge

• Anaerobic Digestion produces carbon dioxide,
  water, and methane (an energy source)
• Composting decomposition to organic material
  used for soil amelioration
• Pasteurization heated to kill pathogens and
  then used as fertilizer

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Sewage Treatment Alternatives

• Septic System (at left) solids sink, liquids
  to leach field
• Irrigation nutrient-rich water used to
  irrigate crops
• Wetlands reconstructed ecosystems can make
  use of the nutrients in sewage

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Policy

• Clean Water Act controls point source
  discharges into water
• Non-point Sources are more difficult to control

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Summary

• Water Pollution categories, sources
• Eutrophication impacts, combating, best
  management practices
• Sewage Treatment preliminary, primary,
  secondary, biological nutrient removal,
  sludge, alternatives
• Policy Clean Water Act, non-point sources