Branch : Mechanical 2 Batch : C Sub. : Environment Study

1. Branch : Mechanical 2 Batch : C Sub. : Environment Study

2. WATER POLLUTION

3. Water Resources and Pollution

4. Contents • Definition of water pollution • Causes of water pollution • Sources of water pollution • Types and results of water pollution • Pollution control

5. What is pollution? • Water pollution is the contamination of water bodies.  Water pollution occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds. • We will be examining water pollution in this prensentation.

6. Causes of Water Pollution • Factors that contribute to water pollution can be categorized into two different groups • Point sources • Non-point sources • Point sources are the easiest to identify and control • Non point sources are specifically defined and harder to control

7. Point Sources • Some point sources of water pollution include • Waste products from factories • Waste from sewage system • Waste from power plants • Waste from underground coalmines • Waste from oil wells • They are called point sources because they are direct sources of water pollution and can be reduced and controlled.

8. Example of a point source

9. Non-point Sources • The term non-point source encompasses a large range of sources such as: • when rain or snow moves through the ground and picks up pollutants as it moves towards a major body of water • the runoff of fertilizers from farm animals and crop land • air pollutants getting washed or deposited in the water • storm water drainage from lawns, parking lots, and streets

10. Non-point source: Agricultural runoff

11. Types and Results of Water Pollution TYPESRESULTS • Infectious agents - million of deaths a year • Organic materials - biological oxygen demand (BOD) increase resulting in oxygen sag • Plant nutrients - eutrophication, toxic tides • Metals - mercury and lead poisoning • Nonmetallic salts - poison seeps and springs • Acids and bases - ecosystem destabilization • Organic chemicals - birth defects, cancer • Sediments - clogged estuaries, death of coral reefs • Thermal pollution - thermal plume

12. Infectious Agents • Main source of waterborne pathogens is untreated and improperly treated human waste. • Animal wastes from farms and fields is also an important source of pathogens. • In developed countries, sewage treatment plants and pollution-control devices have greatly reduced pathogens. • Tests for water quality are done for coliform bacteria (intestinal bacteria). Such tests are easier and cheaper. • Escherichia coli (E. coli) is the major coliform bacterium species

14. Inorganic Pollutants • Metals • Many metals such as mercury, lead, cadmium, and nickel are highly toxic. • Highly persistent and tend to bioaccumulate in food chains. • Lead pipes are a serious source of drinking water pollution. • Mine drainage and leaching are serious sources of environmental contamination. • Nonmetallic Salts • Many salts that are non-toxic at low concentrations can be mobilized by irrigation and concentrated by evaporation, reaching levels toxic to plants and animals. • Leaching of road salts has had detrimental effect on many ecosystems. • Acids and Bases • Often released as by-products of industrial processes.

15. Organic Chemicals • Thousands of natural and synthetic organic chemicals are used to make pesticides, plastics, pharmaceuticals, pigments, etc. • Two most important sources of toxic organic chemicals in water are: • Improper disposal of industrial and household wastes. • Runoff of pesticides from high-use areas. • Fields, roadsides, golf courses

16. Sediment • Human activities have accelerated erosion rates in many areas. • Cropland erosion contributes about 25 billion metric tons of suspended solids to world surfaces each year. • Sediment can either be beneficial (nourish floodplains) or harmful (smother aquatic life).

17. Thermal Pollution • Raising or lowering water temperatures from normal levels can adversely affect water quality and aquatic life. • Oxygen solubility in water decreases as temperatures increase. • Species requiring high oxygen levels are adversely affected by warming water. • Industrial cooling often uses heat-exchangers to extract excess heat, and discharge heated water back into original source. • Thermal Plume • Produce artificial environments which attract many forms of wildlife.

18. Groundwater and Drinking water Pollution • About half the population, and 95% of rural residents, depend on underground water storage for drinking water. • Pollution in ground water can lead to pollution in the drinking water which can cause harmful dieseases such as cholera. • Pollution that seeps into the soil is gone as far as the people that created it are concerned; however, if it moves through that soil it can eventually contaminate groundwater.

19. Groundwater Pollution

21. EUTROPHICATION

22. Eutrophication The word eutrophication is originated from greek words eu = “WELL” and trophes= “FOOD”. Thus it means ‘well fed’ or ‘nutrient rich’. Thus we can define eutrophication as excessive nutrient load in a water body or enrichment of water body by nutrients.

23. Depending upon the increasing levels of productivity, the water bodies can be classified in to Oligotrophic : Water with poor nutrient status and very low productivity of aquatic plants. 2. Masotrophic : Water with moderate nutrient statys and moderate productivity of aquatic plants. 3. Eutrophic : Water with rich nutrient status and high productivity of aquatic plants.

24. Pollution Control • Nonpoint Pollution Sources and Land Management • Reduce nutrient loading through land use regulations • Source reduction is cheapest and most effective way to reduce pollution. • Banning phosphate detergents • Soil Conservation • Sewage Treatment • Remediation

25. Sewage Treatment

26. Sewage Treatment • Rationale • More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water. • Natural Processes • In many areas, outdoor urination and defecation is the norm. • When population densities are low, natural processes can quickly eliminate waste. • Artificial Wetlands Are a Low Cost Method • Natural water purification • Effluent can be used to irrigate crops or raise fish for human consumption.

27. Municipal Sewage Treatment • Primary Treatment - Physical separation of large solids from the waste stream. • Secondary Treatment - Biological degradation of dissolved organic compounds. • Effluent from primary treatment transferred into trickling bed, or aeration tank • Effluent from secondary treatment is usually disinfected (chlorinated) before release into nearby waterway. • Tertiary Treatment - Removal of plant nutrients (nitrates and phosphates) from secondary effluent. • Chemicals, or natural wetlands.

28. Water Remediation • Extraction techniques are used to pump out polluted water for treatment. • Oxidation, reduction, neutralization, or precipitation. • Living organisms can also be used effectively to break down polluted waters.

29. Solutions on Water Pollution • Prevent groundwater contamination • Greatly reduce nonpoint runoff • Reuse treated wastewater for irrigation • Find substitutes for toxic pollutants

30. Solutions on Water Pollution • Work with nature to treat sewage • Practice four R's of resource use (refuse, reduce, recycle, reuse) • Reduce resource waste • Reduce air pollution • Reduce poverty • Reduce birth rates

31. THANKSA LOT