1. Water Pollution and Treatment
Chapter 22
Water Pollution and Treatment

2. Water Pollution Degradation of water quality
Any biological, physical or chemical substance that, in an identifiable excess is known to be harmful to other desirable living organisms
Heavy metals, sediment, radioactive isotopes, heat, coliform bacteria, phosphorus, nitrogen

3. Water pollution
US EPA has set limits on certain pollutants (contaminants)
Difficulties in determining effects of exposure to low levels of pollutants.
Standards have been set for a small fraction of more than 700 identified drinking water contaminants.

4. Surface Water Pollution
Water Pollutants are emitted from
Point Sources
Distinct and confined sources such as pipes from industrial or municipal sources.
Old sewage treatment systems
Nonpoint Sources
Diffused and intermittent
Ex) runoffs from streets, agriculture, mining, forestry.
Difficult to monitor and control

5. Biochemical Oxygen Demand
The amount of oxygen required for biochemical decomposition process
When BOD is high the oxygen content is low, to support life.
3 zones
A pollution zone – BOD high
An active decomposition zone
DO reaches a minimum to
actively decompose
A recovery zone – DO increases
And BOD is reduced

7. Waterborne Disease Outbreaks of waterborne diseases
Milwaukee, WI – Cryptosporidium – 100 deaths
Fecal Coliform Bacteria – 1998 Ga Water Park
Walkerton, ON – E.Coli – Cow manure washed into water supply wells from heavy rains.
5 people died, 20 ICU, 500 ill – CUT BACKS IN TESTING

8. Nutrients Eutrophication Cultural Eutrophication
The process by which a body of water develops a high concentration of nutrients – Phophorus or nitrogen
Cultural Eutrophication
When eutrophication is accelerated by human processes that add nutrients to a body of water
Fertilizers, detergents, sewage treatment plants

12. Eutrophication
A body of water develops a high concentration of nutrients.
The nutrients cause an increase in the growth of aquatic plants as well as photosynthetic blue-green bacteria and algae
Algae may form surface mats, shading and reducing light to the algae below; reducing photosynthesis.
Algae die and decompose, bacteria feed on the dead algae,BOD increases, oxygen is reduced. Other organisms die.

14. Acid Mine Drainage
Water with a high concentration of sulfuric acid that drains from mines
Serious water pollution problem
Damages aquatic ecosystems, pollutes bodies of water and degrades water quality

15. Approaches to surface water pollution
Reduce the sources of pollution
Most environmentally preferable way
Treat the water to remove pollutant
Chlorination
Filtration
Settling Tanks
pH adjustments (Lime)
VOC removal
Nitrate removal

16. Groundwater Pollution
50% of people in US
depend on groundwater
as a water source.
-Groundwater has always
been thought to be PURE
-Pollution sources can be
dumping chemicals, leaking
underground tanks, natural
occurring elements

21. Wastewater Treatment Septic Tank Disposal Systems
Waste Treatment Plants
Primary Treatment
Secondary Treatment
Advanced Treatment
Chlorine Treatment

23. Wastewater Renovation and Conservation Cycle
Steps:
1. Return of treated wastewater to crops
2. Renovation or natural purification by slow percolation of the wastewater into soil to eventually recharge the groundwater resource with clean water
3. Reuse of the treated water

27. Water Reuse Inadvertent: Indirect: Direct:
water is withdrawn, treated and returned to the environment
Indirect:
Ex) the wastewater renovation and conservation cycle
Direct:
The use of treated wastewater that is piped directly from a treatment plant to the next user

28. Water Pollution and Environmental Law
The branch of law dealing with conservation and use of natural resources and control of pollution