This presentation contains enormous information about all the root-causes of different sorts of water pollution, point of origin of various pollutants. It also provides account for remedial measures for mitigating the ill effects of water pollution and the legislation for controlling it.
2. Overview
o Types of Water Pollution
• Sewage
• Disease-causing agents
• Sediment pollution
• Inorganic plant and algal nutrients
• Organic compounds
• Inorganic chemicals
• Thermal pollution
o Water Quality Today
o Improving Water Quality
o Laws related to Water Pollution
3. Water Pollution
o Water pollution
• Any physical or chemical contamination of water that
adversely affects the health of humans and other
organisms
• Varies in magnitude by location
o It is a major issue globally due to lack of clean &
disease-free water
o Eight categories
• Sewage, disease-causing agents, sediment pollution,
inorganic plant and algal nutrients, organic compounds,
inorganic chemicals, radioactive substances, and thermal
pollution
4. Sewage
o The release of wastewater from drains or sewers
• Includes human waste, soaps and detergents
o Causes two serious environmental problems:
• Enrichment
• Fertilization of a water body by high levels of plant and algal
nutrients (nitrogen and phosphorus)
• Increase in Biological Oxygen Demand (BOD)
• Amount of oxygen needed by microorganisms to decompose
biological wastes
• As BOD increases Dissolved Oxygen (DO) decreases
5. Disease-causing Agents
o Infectious organisms that
cause diseases
• Originate in the wastes of
infected individuals
o Common bacterial or viral
diseases:
• Typhoid, cholera, polio and
infectious hepatitis
6. Disease-causing Agents
o Monitored by testing for presence of E.coli in the water
via Coliform Test
o Indicates the presence of pathogenic organisms
7. Sediment Pollution
o Excessive amounts of suspended soil particles
• Originates from erosion of agricultural lands, forest soils
exposed by logging, degraded stream banks, overgrazed
rangelands, strip mines and construction
o Problems
• Limits light penetration
• Covers aquatic animals and plants
• Brings insoluble toxins into waterways
8.
9. Inorganic Plant and Algal
Nutrients
o Chemicals such as nitrogen and phosphorus that
stimulate the growth of plants and algae
• Harmful in large concentrations
o Sources:
• Human and animal wastes, plant residues, atmospheric
deposition and fertilizer runoff
o Causes:
• Enrichment, bad odors and high BOD
10. Organic Compounds
o Chemicals that contain carbon atoms
• Natural examples: sugars, amino acids, and oils
• Manmade examples: pesticides, solvents, industrial
chemicals and plastics
11. Inorganic Chemicals
o Contaminants that contain elements other than
carbon
• Examples: acids, salts and heavy metals
o Do not degrade easily
o Lead
• Found in old paint, industrial pollutants, leaded gasoline
o Mercury
• Mercury bio - accumulates in the muscles of top
predators of the open ocean
12. Radioactive Substances
o Contain atoms of unstable isotopes that
spontaneously emit radiation
o Sources -
• Mining
• Processing of radioactive materials
• Nuclear power plants
• Natural sources
13. Thermal Pollution
o Occurs when heated water
produced during industrial
processes is released into
waterways
o Organisms affected
• Temperature affects
reproductive cycles,
digestion rates, and
respiration rates
• Warm water holds less DO
than cold water
14. Quality of Water Today
o Two types of Water Pollution
o Point Source Pollution
• water pollution that can be traced to a specific origin
• Discharge via pipes, sewage and ditches
o Non-Point Source Pollution
• Pollutants that enter bodies of water over large areas
rather than being concentrated at a single point of entry
• Runoff from agricultural fields or parking lots
15. Industrial Wastes in Water
o Different industries generate different pollutants
• Food Processing Plants - high BOD
• Paper Mills - high BOD as well as toxic compounds
• Textile Industry - Nitrogen , heavy metals and dyestuffs
o Many industries recover toxins before they go into the
waste stream
16. Water Pollution from
Agriculture
o Agriculture is also a source of water pollution
worldwide
• Animal wastes and plants residues have high BOD
• Chemical pesticides can leach into groundwater
o Almost all streams and rivers are polluted with
agricultural pesticides
18. Indian Scenario
o Pollution in Ganges
• Used for bathing and washing
clothes
• Sewage and hazardous
industrial waste discharged
directly into river
• Ganga Action Plan initiated by
government in 1985
• Namami Gange mission is
carried out since 2015
19. Water Pollution in Other Countries
o Po River, Italy
• Similar to Mississippi River of US
• Pollutants: Sewage, Industrial waste, Sediment
• More than 16 million Italians depend on the river for
drinking water
• Pollution is too high
• Swimming and fishing prohibited
• Cleanup will require a national management plan and
may take decades
21. Improving Water Quality -
Treatment of Sewage
Primary Treatment
• Removing suspended and floating particles by mechanical
processing
Secondary Treatment
• Treating wastewater biologically to decompose suspended organic
matter thereby reducing BOD
• Sewage Sludge is eliminated after these treatments
Tertiary Treatment
• Advanced wastewater treatment methods that aresometimes
employed after above treatments
• Reduces Nitrogen as well as phosphorus from water
23. Laws related to Water Pollution
The Water(Prevention and Control of Pollution)Act, 1974
• To provide for prevention control and abatement of water
pollution
• To maintain or restore the wholesomeness of water in country
• To prevent the pollution of water by agricultural industrial and
household sources
• To assess the pollution levels and punish polluters