GEOG 3000 Resource Management 16' Protecting Water Resources Pollution Prevention

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GEOG 3000 Resource Management16. Protecting
Water Resources - Pollution Prevention

• M.D. Lee CSU Hayward Fall 2002

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Sediment Pollution

• Eroding sediments result in a variety of physical
  and chemical pollution from raised turbidity
  and total suspended solids to increased pesticide
  and heavy metal concentrations (they attach to
  soil).
• Soil erosion controls are our major input
  protection against sediment.
• We have already discussed agricultural soil
  conservation.
• In urban areas, a big sediment source is
  construction.
• You may have noticed the many and varied ways we
  now control construction erosion straw bale
  filters, silt fences, hydroseeding, straw
  mulching, burlap geotextiles.
• Output controls are costly constructing
  silting ponds and marshes dredging channels and
  reservoirs treatment plant sedimentation,
  coagulation filtration.

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Nutrients

• A variety of inorganic chemicals leach into our
  water from fertilizers, animal waste and sewage
  nitrates, phosphates, etc.
• They can lead to eutrophication and massive algal
  blooms which then die and are decayed by oxygen
  demanding organisms, reducing dissolved oxygen
  levels and killing aquatic life and tainting
  water.
• Many input and output controls exist, from
  building tertiary wastewater treatment plants to
  switching to phosphate-free detergents (see
  p257-258 in CRO).

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Thermal Pollution

• Induced changes of temperature in water bodies is
  considered a physical pollutant, both hot and
  cold water can create problems.
• Cold normally results from the release of stored
  water from the bottom of a reservoir.
• Heat comes from the release of heated water used
  in thermal or nuclear power production and
  creates a range of biological impacts.
• The input solution for hot wastewater is to pass
  it through cooling towers or to pipe water to
  locations where the heat can be put to good use
  to heat homes, etc. and be cooled in the
  process (helps conserve energy!).

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Pathogens and Parasites

• High levels of morbidity and mortality are caused
  worldwide by disease-causing organisms in water
  consumed and used by humans.
• Human and animal waste contain enormous numbers
  of coliform bacteria which we can test for in
  water to determine the level of output control we
  might need.
• Input controls require effective sanitation
  and/or wastewater treatment, also the control of
  animal wastes in watersheds.
• Output controls require filtration and
  purification with some form of oxidizing agent
  like chlorine, chloramine and/or ozone.
• The Safe Drinking Water Act sets strict
  guidelines for output controls and allows zero
  pathogens in drinking water.

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Toxic Organics

• With the massive use of hydrocarbons in industry
  and transportation, the modern era has produced
  hundreds of thousands of different organic
  chemicals, many of which are harmful, soluble and
  persistent in water.
• We have used our environment as a sink for many
  of these wastes dumping in rivers, in
  landfills, in seepage ponds or deep injection
  wells - with suspected health and ecological
  damages.
• The best controls are all input specialized
  pre-treatment and isolation of industrial wastes,
  prevention of leaking storage tanks, elimination
  of the most harmful chemicals in industry, etc.
• Output controls/clean ups are expensive reverse
  osmosis, carbon filtration, air sparging, etc.

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Heavy Metals

• Heavy metals are important human poisons with
  both chronic and acute effects.
• Many can bioaccumulate in tissues and disrupt
  biological processes in humans and other
  organisms.
• Heavy metals come principally from mining and
  industry that disturb, process or use
  metal-bearing ores and finished metals.
• Input controls require pollution prevention
  from controlling air pollution, to isolating mine
  drainage and separating industrial waste streams
  for pretreatment, and remedial clean up of past
  pollution.
• Output controls are difficult and very expensive
  carbon filtration, electrolysis, etc.

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O2 Demand (BOD/COD)

• We measure the level of oxygen-demanding
  substances (decomposable organic material) in
  water by the variables of biological and chemical
  oxygen demand (BOD/COD).
• Most normal aquatic life requires a moderate to
  high level of dissolved O2 in water (i.e. gt5
  mg/l) and if it drops, they die from
  asphyxiation.
• Input control requires prevention of nutrient and
  thermal inflow (see earlier) and the treatment of
  oxygen-demanding wastes to lower BOD/COD.
• Sewage treatment facilities and animal feedlot
  retention and oxidation lagoons are major weapons
  in limiting oxygen demand.

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Sewage Treatment

• CRO provide a nice summary on p274-278.
• Most communities in the US have up to secondary
  treatment.
• More than 90 of cities in the developing world
  have no treatment, only collection and discharge.

(Source Wright Nebel, 2002)