1. Do Now:
Where does our water go when we flush the toilet? Wash our hands in the sink? Water our lawns, wash our cars?

2. Aim: How Can We Best Deal with Water Pollution?
Concept Reducing water pollution requires we prevent it, work with nature to treat sewage, cut resource use and waste, reduce poverty, and slow population growth.

3. Reducing Surface Water Pollution from Nonpoint Sources
Agriculture
Reduce erosion
Reduce the amount of fertilizers
Plant buffer zones of vegetation
Use organic farming techniques
Use pesticides prudently
Control runoff
Tougher pollution regulations for livestock operations
Deal better with animal waste

4. Pause…Think…Write…
Should we greatly increase efforts to reduce water pollution from non point sources even though this could be quite costly?

5. Laws Can Help Reduce Water Pollution from Point Sources
1972: Clean Water Act : sets limits for 100 water pollutants and requires polluters to get permits that limit how much they can discharge.
1987: Water Quality Act: strengthened the federal water quality regulations by providing changes in permitting and adds substantial penalties for permit violations.

6. Laws Can Help Reduce Water Pollution from Point Sources
EPA: experimenting with a discharge trading policy that uses market forces
Cap and trade system
Could this allow pollutants to build up? Lower the cap!

7. Do you understand how laws can be both good and bad?

8. Case Study: The U.S. Experience with Reducing Point-Source Pollution
Numerous improvements in water quality
Some lakes and streams are not safe for swimming or fishing -40%
Treated wastewater still produces algal blooms
High levels of Hg, pesticides, and other toxic materials in fish

9. Case Study: The U.S. Experience with Reducing Point-Source Pollution
Leakage of gasoline storage tanks into groundwater
Many violations of federal laws and regulations (unclear which water ways are covered under CWA)
Need to strengthen the Clean Water Act: fines are cheap!

10. Solutions: Septic Tank System

11. Waste water treatment from flush to finish movie
What happens during the primary, secondary, and tertiary treatment of waste water?

12. Solutions: Primary and Secondary Sewage Treatment

13. We Can Improve Conventional Sewage Treatment
Peter Montague: environmental scientist
Remove toxic wastes before water goes to the municipal sewage treatment plants
Reduce or eliminate use and waste of toxic chemicals
Use composting toilet systems
Wetland-based sewage treatment systems

14. Science Focus: Treating Sewage by Working with Nature
John Todd: biologist
Natural water purification system
Sewer water flows into a passive greenhouse
Solar energy and natural processes remove and recycle nutrients
Diversity of organisms used

15. Solutions: Ecological Wastewater Purification by a Living Machine, RI, U.S.

16. There Are Sustainable Ways to Reduce and Prevent Water Pollution
Developed countries
Bottom-up political pressure to pass laws
Developing countries
Little has been done to reduce water pollution
China : ambitious plan

18. Summary:
What role does population growth play in the problems of groundwater and coastal water pollution?