Water pollution may occur when the contamination of water find it. Water pollution mostly attempts only when pollutants are drained directly or indirectly into water bodies without any proper treatment to remove harmful substances.
There are two basic sources of water, surface water, and groundwater. Surface water comes from streams, lakes, rivers, shallow wells and reservoirs created by dams. Greatest surface water contains suspended solids, microbes, organic and inorganic substances and another biota. If these substances are present in water at an optimum level, they do not cause pollution. When the concentration of these materials or organisms are high, they diminish the quality of water and make it unfit for recreational, domestic, industrial or other use. Some substances like industrial poisons, toxic chemicals, and pathologic organisms pollute the water even at very low concentrations.
Impurities get added to it as it percolates beneath the surface of the earth and also when it is used for human movements. Water pollution can be defined as the presence in water, of some foreign Substances or impurities like organic, inorganic, radiological or biological in such quantity so as to constitute a health hazard by lowering the water quality and making it unfit for use.
Signs of Water Pollution:
Bad taste of drinking water;
Offensive odours from lakes, rivers, and ocean beaches;
These disturb the normal uses of water for public water supply:
Recreation and aesthetics; Fish, other aquatic life, and wildlife; Agriculture; Industry;
Unchecked growth of aquatic weeds in water bodies;
Decrease in number of fish in fresh water, river water, sea water;
Oil and grease floating on water surfaces.
The main Sources of Water Pollution:
There are two major sources of water pollution, namely:
1 Point experts and
2 Diffused experts.
1. Point Experts:
These are the source which can be identified at a single location are known as point sources. We see the flow of water pollutants through regular channels like sewage systems, industrial effluents etc. infiltration of industrial effluents, municipal sewage etc. contamiÂ¬nate the groundwater and cause water pollution.
2. Diffused Experts:
Those sources whose location cannot be easily distinguished are called diffused sources. When the pollutants wasted on the ground finally reach the water sources and cause water pollution, agriculture’s pesticides, fertilizers, mining, construction.
There are some Common Sources of Water Pollution
The sources in which the water resources are being contaminated continuously:-
The main source of pollution is partially treated sewage discharged into rivers, lakes, and streams. The demobilization of huge quantities of municipal and domestic wastes and sewage pollute many water bodies. Sewage consists of rich in organic matter and nitrogen compounds.
Sewage is effected on an ecosystem. Sewage increases the biological productivity and interferes with many uses of the water body. Waste containing toxic substances damage biological activity and kill useful organisms.
A large number of industrial wastes are continuously dropped into streams, rivers, and lakes. The common industries are found that cause pollution is printing, electroplating, soap manufacture, food products, rubber and plastics, chemicals, textiles, steel, sugar factories, glass manufacture. Industrial wastes can also percolate through the soil and pollute the groundwater.
Caustic soda and chlorine industries release heavy metals such as cadmium, chromium, copper, lead, nickel, zinc and mercury.The paper mill wastes like coak works and plastic wastes have many phenolic compounds. Metal finishing plants release heavy metals and cyanide.
Cadmium and chromium present in the sea are toxic to marine animals. When Mercury enters the human body through contaminated fishes. Many molluscs in streams are found to accumulate considerable amounts of copper and zinc.
For agricultural pollution is directly concern with Pesticides and Fertilizers which can also lead to water contamination. Some other causes are the uncontrolled spreading of slurries and manure, disposal of sheep dip, tillage and ploughing of the land.
A major part of fertilizer become available for excessive algal growth. This is more true for nitrogenous fertilizers (which are readily soluble) than phosphatic ones.
Bacteria normally found in the water are able to convert nitrate ions fertilizers and organic wastes to nitrite. The concentration of nitrates and nitrites are reduced naturally by the action of the denitrifying bacteria in water and soil.
DDT, DDE, DDD, Delrin and polychlorinated biphenyls are washed down with rainwater and find their way to the sea through rivers and streams. The toxic contaminated particles accumulate in the bodies of aquatic organisms and cause a great harm to them. The excessive use of pesticides causes water pollution, by penetrating through the soil and getting dissolved in soil water.
The pesticide is the general term for insecticides, acaricides, rodenticides, molluscicides, herbicides, fungicides and similarly active compounds.
Oil spillages affect water quality in very bad manners. Oil makes our drinking water unsafe to utilize for human purposes. Oil spills also reduce oxygen supplies within the water ecosystem.
The main causes of oil-related water pollution are:-
1. Loss from storage facilities, 2. Spillage during delivery and;3. Deliberate disposal of waste oil to drainage systems.
Radioactive waste is the major source of water pollution. Radioactive substances are basically used in nuclear power plants, industrial, medical and other scientific purposes. These type of substances can result in a great water pollution incidents.
People dump their garbage wastes and some other organic and inorganic substances into water sources. Water dumping substances cause water pollutant. It harms the ecosystem and increases the risk of flooding.
Thermal pollution is the discharge of hot water into the river. This may be affect the pollutant when the temperature of the water, thereby increasing the metabolic rate and oxygen consumption of microorganisms. This makes it all the more difficult for fish to survive.
Mining causes water pollution saw weeds from hydro mining methods and in the form of acid drainage from coal mines, debris.
Earthmoving construction projects, deforestation and flood results may interrupt or prevent the reproduction of fish by smothering eggs laid on the bottom.
Classification of Water Pollutants:
Synthetic Organic Pollutants:
These include plasticizers, fibres, elastomers, fuels, plastics, solvent, detergents, paints, insecticides, food additives and pharÂ¬maceuticals.
This presence in water imparts objectionable and offensive tastes, odours and colours to fish and aquatic plants even when they are present in low concentrations.
Inorganic Pollutants may be raise due to inorganic salts, minerals, acids, finely divided metals or metal compounds, trace elements, complexes of metals with organic in natural water, and organometallic compounds.
Such interactions depend on and play a role in redox equilibrate, colloid formation, acid-base reactions and microorganisms mediated reactions in water. These have an impact on the toxicity of metals in aquatic ecosystems and on the growth of algae in the water.
Polyphosphate in detergents may also cause the Inorganic Pollutant.
Effects of Water Pollution:
Pollutants of water may be influenced with physical and chemical changes in water, for instance, suspended particles make water turbid; dyes, chromium, and iron compounds change the colour of water; phenols, oils, detergents, hydrocarbons, chlorine are imparted an unpleasant taste to water.
The Contamination of water has immediate effects on our health and environment of living organisms.
Health Hazards of Water pollution:
Fertilizers and detergents pollute surface level of waters where they act as nutrients and promote the growth of oxygen-consuming algae which reduce the D.O. level of water, killing fish and other aquatic organisms. Phosphorus and Nitrates are the basic compounds.
An industrial pollutant is the most common that may effect poisonous chemicals such as Arsenic, Mercury, Cadmium, Lead which kill aquatic organisms and may reach human body through contaminated food.
Non-biodegradable pesticides (especially organochlorines) travel through food chains and ultimately reach human body where they accumulate in the fatty tissues and affect the nervous system.
Water contaminated particles may raise diseases like typhoid, bacillary dysentery, cholera, and amoebic dysentery signify the predominant health hazards arising from drinking contaminated water.
Fluoride-containing pollutants cause fluorosis i. e. neuromuscular, respiratory gastrointestinal and dental problems.
Thermal pollution of water may reduce the D.O. level of water that can make itself incapable of supporting life.
Oil pollutants are the most common response to the death of many water birds and fishes.
Control of Water Pollution
Well-designed and operating systems can remove 90 percent or more of these pollutants. But there are some municipal plants which are not designed to treat toxic pollutants found in industrial wastewater.
Domestic sewage may be treated properly including –
Try to repair or replace the leaking or any malfunctioning equipment. Approaching a green infrastructure to improve stormwater management system and reduce the hydraulic overloading of the treatment plant. Try to increase the overall hydraulic capacity of the sewage system at any cost.
As we all are aware that most of the industries generate wastewater with high concentration of conventional pollutants oil and grease, toxic pollutants-Heavy metals, non-conventional pollutants such as ammonia. The facilities which could be needed to remove the toxic pollutants should be installed with a pre-treatment system.
Cooling towers, which transfer waste heat to the air through the process of evaporation.Cooling ponds, man-made water bodies which are designed for cooling by evaporation, convection, and radiation. Cogeneration, a process where waste heat is recycled for domestic and for industrial heating purposes
Agricultural Waste Water
Nonpoint source controls
Farmers may use common techniques include contour ploughing, crop mulching, crop rotation, planting perennial crops and installing riparian buffers. The farmers as commercial fertilizers, animal manure or spraying of municipal or industrial wastewater or sludge. Farmers can reduce misuse of chemical fertilizers.
Point source wastewater treatment
The Slurries and wattage, garbage of animal slurries are used by mixing with straw and composted at high temperature to produce bacteriologically sterile and manure for soil fertilization.
1. Thermal Decomposition:
We need to the conversion of hot water into cooled before releasing from factories, and removal of forest canopies and irrigation return flows should be banned.
Besides reserving separate water supplies for livestock, the following banned should be enforced to avoid contamination of the main sources of drinking water.
Stop throwing bathing and washing of clothes in rivers and streams.
3. Judicious Use:
Pesticides and fertilizers should be very judiciously used to avoid chemical pollution of water through agricultural farm run-offs.
4. Reuse of Water:
Treated water can be reused for recreation purposes like fishing and boating.
The contaminated water may be used in industrial water supply, irrigation or municipal purposes, cooling processes in thermal plants.
Controlling water pollutant is legal provisions regarding water pollution should be enforced by a special administrative machinery comprising of highly qualified and experienced personnel.
Clean water is essential for a healthy environment to support life systems on this planet.
Moreover, anthropogenic global and local climatic distorÂ¬tions resulting from global warming due to denudation of forest canopy, loss of topsoil, greenhouse gases, severe environmental degradation have an adverse impact on the monsoon pattern in India.
Hence in-spite of vast water resources in lakes and rivers and good monÂ¬soon, India faces perennial problems of floods and droughts and highly polluted water resources.