Water Quality and Usage

The Hydrologic Cycle

Water Sources and Uses

Source: Aquatic Chemistry, 2nd Ed. by W. Stumm and J. J. Morgan

Typical Water Consumption

• In the US
  • Household: 100 to 250 Gal/person-day
  • Agriculture: 500 to 1000 Gal/person-day
  • Industrial: 1000 to 1500 Gal/person-day
• Other areas of the world:

Measuring Water Quality

Biological Quality

• Number of microorganisms (usually a specific bacteria) per volume
  • Commonly the coliform group used to indicate human fecal contamination
  • Rarely specific pathogenic microorganisms

Chemical Quality

• Inorganic compounds
  • Concentration of toxic metals such as lead, chromium, copper, zinc
  • Concentration of hardness metals such as calcium, magnesium
  • Concentration of anions such as nitrate, carbonate
• Organic compounds
  • Concentration of specific toxic compounds such as THMs, pesticides, others
  • The amount of oxygen the waste microorganisms in the water will consume as they utilize the waste. This is important because much of the aquatic life (fish, crustaceans) requires oxygen.
  • Concentration of suspended solids of water or wastewater

Water Quality Regulations

1948 -- Water Pollution Control Act

1956 -- Federal Water Pollution Control Act

1961 -- Amendments to the FWPCA

1965 -- Water Quality Act

1966 -- Clean Water Restoration Act

1972 -- Federal Water Pollution Control Act Amendments (Clean Water Act) with $7 billion for improved wastewater treatment facilities

1977 -- Clean Water Act with $5 billion additional funding

1981 -- Municipal Wastewater Treatment Construction Grants Amendments

1987 -- Water Quality Act with $2.4 billion in funding

Sources of Water Pollution

• Municipal wastewater discharges: 100 to 250 Gal/person-day
• Agriculture: as runoff or infiltration
• Industrial discharges
  • only a small fraction of total use is discharged as polluted water
  • most is returned as "non-contact cooling water," warmer, but otherwise uncontaminated

Water Conservation in the Home

• Pressure reduction
• Flow control on sinks, showers
• Don't let the faucet run when not in use
• Water-saving toilets
• Front loading washing machines
• Wash only full loads
• Check for leaks
• Water saving dishwashers
• Wash your car less
• Water lawns early or late and less

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