1. Chapter 22
Water Pollution

2. Types of Water Pollution
Sewage
↑ Enrichment
Explosion in algal, bacteria, & decomposer populations
↑ Biological oxygen demand
Fish kills
↓ Oxygen levels in water

3. Types of Water Pollution
Effect of sewage on dissolved oxygen and biological oxygen demand

4. Types of Water Pollution
Eutrophication: An Enrichment Problem
Oligotrophic lake

5. Types of Water Pollution
Eutrophication: An Enrichment Problem
Eutrophic lake

6. Types of Water Pollution
Disease-Causing Agents

7. Types of Water Pollution
Disease-Causing Agents
Monitoring for Sewage
Fecal coliform test

8. Types of Water Pollution
Sediment Pollution
Low sediment load

9. Types of Water Pollution
Sediment Pollution
High sediment load

10. Types of Water Pollution
Inorganic Plant and Algal Nutrients
The Dead Zone in the Gulf of Mexico

11. Types of Water Pollution
Organic Compounds

12. Types of Water Pollution
Inorganic Chemicals
Lead
Mercury

13. Types of Water Pollution
Radioactive Substances
Thermal Pollution

14. Water Quality Today Point source pollution (e.g., cyanide spill)
Nonpoint source pollution
(e.g., fertilizer runoff from agriculture fields)

15. Water Quality Today Water Pollution from Agriculture
72% of water pollution in rivers attributed to agriculture
Chemical pesticides may leach into soil and then into water.

16. Water Quality Today
Municipal Water Pollution

17. Water Quality Today Industrial Wastes in Water
Problems depend upon industry
Food processing  high BOD
Paper mills  toxic compounds & sludge
Many US industries now treating wastewater
(some can recover merchantable products)

18. Water Quality Today
Groundwater Pollution

19. Water Quality Today Water Pollution in Other Countries
Lake Maracaibo, Venezuela

20. Water Quality Today Water Pollution in Other Countries Po River, Italy
- Equivalent of the Mississippi River,
- Sewage, industrial wastes, sediment
- >16 million Italians depend on the river for drinking water
- Pollution is so bad, swimming has been suspended in parts, jeopardized tourism and fishing

21. Water Quality Today Water Pollution in Other Countries
Ganges River, India

22. Water Quality Today Water Pollution in Other Countries Kwale, Kenya
- Water contaminated with disease-causing organisms
- Led to cholera and diarrhea outbreaks

23. Water Quality Today Water Pollution in Other Countries
Arsenic Poisoning in Bangladesh
- In 1980s world health organizations, sponsored digging wells
- Unfortunately, naturally occurring arsenic led to wide-spread poisoning

24. Improving Water Quality
Purification of Drinking Water
General process:
Collected from reservoir or ground water.

25. Improving Water Quality
Purification of Drinking Water
General process:
Water treated

26. Improving Water Quality
Purification of Drinking Water
General process:
Distributed to customers
Wastewater collected as sewage

27. Improving Water Quality
Purification of Drinking Water
General process:
Sewage treated

28. Improving Water Quality
Purification of Drinking Water
Purification issues:
The Chlorine Dilemma
Fluoridation

29. Improving Water Quality
Municipal Sewage Treatment
Primary and Secondary Sewage Treatment

30. Improving Water Quality
Municipal Sewage Treatment
Effectiveness of primary, secondary, and tertiary sewage treatment

31. Improving Water Quality
Municipal Sewage Treatment
Major problem associated with wastewater treatment is disposal of sludge
Can be used as fertilizer, but there may be health risks (e.g., heavy metal poisoning)
Used to be dumped in ocean, that is now banned
Currently, most dumped in landfills

32. Improving Water Quality
Individual Septic Systems
Septic tank

33. Improving Water Quality
Individual Septic Systems
Drain field

34. Laws Controlling Water Pollution
Safe Drinking Water Act
set the maximum contaminant level for drinking water
Clean Water Act
pertained to improving quality of rivers, lakes, aquifers, estuaries, and coastal waters

35. Laws Controlling Water Pollution
Case-in-Point: Water Pollution in the Great Lakes

36. Laws Controlling Water Pollution
Laws That Protect Groundwater
Safe Drinking Water Act
Resource, Conservation, and Recovery Act