1. 21
Water Pollution

2. Overview of Chapter 21 Types of Water Pollution Water Quality Today
Municipal
Agricultural
Industrial
Improving Water Quality
Laws Controlling Water Pollution
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3. Types of Water Pollution
Any physical or chemical change in water that adversely affects the health of humans and other organisms
Problem in developing countries: lack of disease free.
Eight categories
Sewage, disease-causing agents, sediment pollution, inorganic plant and algal nutrients, organic compounds, inorganic chemicals, radioactive substances, and thermal pollution
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4. Sewage The release of wastewater from drains or sewers
Causes 2 serious environmental problems:
Enrichment
Fertilization of a body of water by high levels nitrogen and phosphorus.
Sewage and other organic wastes are measures by biochemical oxygen demand (BOD).
Increase in Biological Oxygen Demand (BOD) (in milligrams of dissolved oxygen per liter of water for a specific number of days at a given temperature).
A large amount of sewage in water generates a high BOD which robs the water of dissolved oxygen.
When dissolved oxygen levels are low, anaerobic microorganism produce compounds with unpleasant orders which deteriorate water quality.
As BOD increases, Dissolve Oxygen (DO) decreases
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5. Sewage
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6. Sewage - Eutrophication
Oligotrophic
Unenriched, clear water that supports small populations of aquatic organisms
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7. Sewage - Eutrophication
Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus. The enrichment of water results in an increased photosynthetic productivity. The water in eutrophic lake is a cloudy and usually resembles pea soup b/c of the presence of algae.
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8. Disease-causing Agents
Disease-causing agents are infectious organism that cause disease; they come from the wastes of infected individuals. Municipal wastewater usually contains many bacteria, viruses, protozoa, parasitic worms and other infectious agents that cause human or animal disease.
Infectious organisms that cause diseases
Originate in the wastes of infected individuals
Common bacterial or viral diseases:
Typhoid, cholera, bacterial dysentery, polio, and infectious hepatitis
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9. Monitoring for Disease from Sewage
Monitored by testing for presence of E. coli in the water via a fecal coliform test
Small sample of water is passed through a filter to trap all bacteria. The filter is then transferred to a Petri dish that contains agar.
Indicates the presence of pathogenic organisms
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10. Monitoring for Disease from Sewage
When dangerous levels of fecal coliform bacteria are discovered in a stream or other body of water. Important to determine source of contamination.
Bacterial source tracking (BST) allows investigators to identify subtle difference in strains of E. coli on the basis of their animal host.
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11. Sediment Pollution
Excessive amounts of suspended soil particles. (clay, silt, sand and gravel are suspended and carried in water.)
Sediment pollution occurs when excessive amounts of suspended soil particles eventually settle out and accumulate on the bottom of a body of water.
Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction
Problems
Sediments that settle out of the water and form a layer over coral reefs or shellfish beds can clog the gills and feeding structures of aquatic animals.
Limits light penetration
Covers aquatic animals and plants
Brings insoluble toxins into waterways ( which makes the water turbid so cloudy). This reduces the ability of producers to photosynthesize.
Affect water Quality by carrying toxic chemicals both inorganic and organic into the water.
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12. © 2012 John Wiley & Sons, Inc. All rights reserved.

13. Inorganic Plant and Algal Nutrients
Nitrogen and phosphorus that stimulate the growth of plants and algae
Harmful in large concentrations
Sources:
Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff
Causes:
Enrichment, bad odors, and a high BOD
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14. Inorganic Plant and Algal Nutrient- The Dead Zone
Dead Zone in Gulf of Mexico: nitrogen and phosphorus from the Mississippi River are largely responsible for huge dead zones.
Dead zones are a sections of the ocean or a sea in which oxygen has been d depleted to the point that most animals and bacteria cannot survive often caused by runoff of chemical fertilizers.
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15. Organic Compounds Chemicals that contain carbon atoms
Natural examples: sugars, amino acids, and oils
Human-made examples: pesticides, solvents, industrial chemicals, and plastics
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16. Volatile Organic Compounds in Groundwater
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17. Inorganic Chemicals
Contaminants that contain elements other than carbon
Do not degrade easily
Lead
Found in old paint, industrial pollutants, leaded gasoline.
Contaminates water when the water passes through the pipes of older homes that contain lead lined pipes brass fitting containing lead and lead containing material.
Exposure can damage the brain nervous system and kidneys.
Mercury
Mercury is found in increase concentrations in water as result of human activities. Coming from the burning of fossil fuels mainly coal, incineration of garbage, hazardous waste, medical supplies, and dental supplies and raw supplies to make cement.
Mercury bioaccumulates in the muscles of top predators of the open ocean. This is found in fish and shellfish.
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18. Radioactive Substances
Contain atoms of unstable isotopes that spontaneously emit radiation
Sources
Mining
Processing radioactive materials
Medical and Research Facilities
Nuclear power plants
Natural sources
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19. Thermal Pollution Nonchemical water pollution.
Occurs when heated water produced during industrial processes is released into waterways. Usually occurs when cold water is removed from a natural supply, used to absorb heat as part of some industrial process, and then returned as heated water back to the natural supply.
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20. Thermal Pollution Organisms affected
Temperature affects reproductive cycles, digestion rates, and respiration rates
Warm water holds less DO than cold water so it increase respiration rate which then suffocate.
Thermal shock- A phenomenon which, dramatic change in temperature can kill many species,
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21. Two Types of Water Pollution
Point Source Pollution
Water pollution that can be traced to a specific origin. Distinct locations such as particular factory that pumps its waste into a nearby stream or a sewage treatment plant that discharges it wastewater from a pipe in an ocean.
Non-point Source Pollution
Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry
Diffuse, but its cumulative effect is very large
Example: Entire farming region, suburban community with many lawns and septic system or storm runoff from parking lots.
It is important to differentiate between the 2 types of pollution sources because the distinction can help in controlling polluants inputs to waterways.
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22. Water Pollution from Agriculture
Agriculture is leading source of water pollution in US
Animal wastes and plants residues have high BOD
Chemical pesticides can leach into groundwater
Almost all streams and rivers are polluted with agricultural pesticides
72% of water pollution in rivers is from agriculture
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23. Municipal Water Pollution
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24. Industrial Wastes in Water
Different industries generate different pollutants
Food processing plants - high BOD
Paper mills - High BOD and toxic compounds
Many industries recover toxins before they go into the waste stream
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25. Case-In-Point Green Chemistry- Sources of synthetic pollutants in water
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26. Groundwater Pollution
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27. Water Pollution in Other Countries
Lake Maracaibo, Venezuela
10,000 drill platform oil wells tap lake bottom
Leak oil into lake
Agricultural wastes from local fields
Until recently, raw human waste polluted the lake
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28. Water Pollution in Other Countries
Po River, Italy
Similar to Mississippi River
Pollutants: Sewage, industrial wastes, sediment
~17 million Italians depend on the river for drinking water
Cleanup will require a national management plan and may take decades
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29. Water Pollution in Other Countries
Ganges River, India
Used for bathing and washing clothing
Sewage and industrial waste discharged into river
Ganga Action Plan initiated by government
Construction of 29 sewage treatment plants
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30. Purification of Drinking Water
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31. Purification of Drinking Water
In US most municipal water supplies are treated
Collected from water or reservoir
Treated
Treated water distributed to customers
Sewer lines bring sewage to treatment plant
Sewage treated at sewage treatment plant
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32. Purification of Drinking Water
Chlorine Dilemma
Chlorine byproducts are linked to numerous cancers, miscarriages and birth defects
Peru stopped using chlorine
huge cholera epidemic that infected 300,000 people
Fluoridation
70% of US drinking water is fluoridated
Prevents tooth decay
Once believed to be linked to cancer, kidney disease - current studies do not show this
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33. Municipal Sewage Treatment
Primary treatment
Removing suspended and floating particles by mechanical processes
Secondary treatment
Treating wastewater biologically to decompose suspended organic material; reduces BOD
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34. Secondary Treatment Most common treatment, activated sludge.
Wastewater from primary sedimentation tank enters the tank
Then enters the final sedimentation tank
Sludge settles out
Some activated sludge used again in aeration
Most of the sludge transported to digester
Wastewater from final tank is disinfected w/ chlorine and discharged

35. Secondary Treatment Secondary treatment removes ~90% of BOD
Sludge from the digester is dried and disposed of in a landfill, burn, anaerobic digestion, or applied to improve soil.

36. Municipal Sewage Treatment
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39. Municipal Sewage Treatment
Sewage Sludge
Solids remaining after primary and secondary sewage treatment has been completed
Tertiary treatment
Advanced wastewater treatment methods that are sometimes employed after primary and secondary treatments
Reduce phosphorus and nitrogen
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40. Municipal Sewage Treatment
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41. Individual Septic System- Septic Tank
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42. Individual Septic System- Drain Field
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43. Laws Controlling Water Pollution
Citizen Watchdogs to Monitor Pollution
Clean Water Act- (1972) supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water”.
-Issued water quality standards that defined acceptable limits of various pollutants in U.S. waterways.
Safe Drinking Water Act- (1974, 1986, 1996) sets the national standards for safe drinking water.
- It is responsible for establishing maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater.
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44. Laws that Protect Groundwater
Safe Drinking Water Act
National Pollutant Discharge Elimination System (NPDES)
Resource, Conservation and Recovery Act
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