1. Chapter 21 Water Pollution and Treatment
Categories of water pollutants
Diseases of drinking water
Point vs. non point source pollution
BOD
Eutrophication
Sediment
Acid Mine Drainage
Aquifer Pollution
Waste Water treatment
Environmental Laws to protect drinking water

2. Categories of Water Pollutants
Sediment
Heavy metals
Radioactive isotopes
Heat
E coli, pathogens, viruses
Nutrients
Dead organic matter

3. Introduction US EPA sets standards for over 700 water pollutants
Disease free water available in U.S., not necessarily problem except in developing world
Sources of surface and groundwater pollution (industry, agriculture, urban)
Runoff
Spills
Leaks
Sediment
Air fallout
Seepage

4. BOD What is it? Water quality parameter
Measured before after at treatment facility and in stream
Measure of oxygen for biochemical decomposition processes
Amount of oxygen consumed by microorganisms in organic matter breakdown

5. BOD Trends Natural and unnatural sources BOD
1/3 BOD comes from ag runoff
Threshold- <5mg/l water
Vocabulary- pollution zone, active decomposition zone, recovery zone

6. Relationship BOD vs. Dissolved Oxygen
plant
spill
stream
BOD
concentration
low
high
Return to normal
increases
Stable amounts
Break down organic matter
Low O2 species

7. Water Borne Diseases Outbreaks (sudden occurrences) examples
Cryptosporidium - resistant to Cl, caused 100 deaths in Milwaukee
sources cattle, sewage, snow melt
Installed new filtration system
E coli – Ontario, delayed reporting and treatment, boil water, 500 sick, source?- cow manure
continuously monitored, <200 cells/100ml water, EPA standard, exceed this amount beach closing and precautions

8. Nutrients-N and P

9. Sediment

10. Acid Mine Drainage

11. Surface Waters Point vs. Non point

12. Groundwater Treatment

13. Septic Tanks Sewage Disposal Systems

14. Hypoxia

15. Waste Water Treatment Plants
Divided into three categories
Primary (30-40% BOD removal)
Raw sewage passed through series of screens to remove large materials
Grit chamber-removes sand, stones
Sedimentation tank- settle out solids (sludge)
Sludge- removed to digester

16. Waste Water Treatment Plants
Secondary treatment
Waste water from primary treatment enters aeration tank
Bacteria in sludge uses oxygen and consumes organics, further reducing BOD
Anaerobic bacteria added to further degrade sludge
Methane gas (anaerobic digestion) either used for energy or burned off
Wastewater treated with chlorine is discharged or used for irrigation
90% BOD removal
Sludge- applied to land or special disposal (heavy metals)

18. Waste Water Treatment Plants
Advanced water treatment
N, P, organics, and heavy metals require carbon and sand filters, chemical treatment

19. p.461 Environmental Laws 1899- Refuse Act 1972- Clean Water Act
1974- Safe Water Drinking Act
1984- Amendment to Resource Conservation and Recovery Act
1987- Water Quality Act

20. LAND APPLICATION OF WASTEWATER