Water pollution control

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Water Resources and Pollution:

Water Resources and Pollution

What is pollution?:

What is pollution? Pollution is the introduction of harmful substances or products into the environment We will be examining 3 main parts of pollution Water Pollution Air Pollution Land Pollution

Causes of Water Pollution:

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 ambiguously defined and harder to control

Point Sources:

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 monitored

Example of a point source :

Example of a point source

Non-point Sources:

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 to earth storm water drainage from lawns, parking lots, and streets

Non-point source: Agricultural runoff:

Non-point source: Agricultural runoff

Types and Results of Water Pollution:

Types and Results of Water Pollution TYPES RESULTS 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

Infectious Agents:

Infectious Agents Main source of waterborne pathogens is untreated and improperly treated human waste. Animal wastes from feedlots 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

Inorganic Pollutants:

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.

Organic Chemicals:

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


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).

Thermal Pollution:

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.

Groundwater and Drinking water Pollution:

Groundwater and Drinking water Pollution About half the population, and 95% of rural residents, depend on underground water storage for drinking water.

Groundwater Pollution:

Groundwater Pollution

Pollution Control:

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

Sewage Treatment:

Sewage Treatment

Sewage Treatment:

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.

Municipal Sewage Treatment:

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.

Water Remediation:

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.

Solutions on Water Pollution :

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

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