Water pollution can be defined as the deterioration of the natural balance of the aquatic environment, mineral ratio, taste, clarity, suspended particles. Substances mixed with water change the physical, chemical and biological properties of water and reveal the phenomenon called water pollution.
Pollution Caused by Agricultural Activities
Pesticides (pesticides) and herbicides (herbicides) used in agricultural fields are compounds that are naturally difficult to decompose in water. Since agricultural tools used in intensively cultivated lands are generally very durable, it can take years to decompose. Unconscious use of fertilizer pollutes groundwater and surface waters, increases the hardness of drinking water, and causes the death of living things in lakes and rivers. These cause both soil pollution and pollution of water resources.
Another type of contamination is erosion. A large amount of arable land is lost by erosion. The decrease in agricultural production due to the destruction of fertile soil, deterioration of quality, deficiencies in the food chain, as well as soils carried by erosion affect the in-water ecological balance by creating turbidity in the seas and streams.
Pollution Caused by Industrial Activities
As it is known, industrial water is an important factor in water consumption in the world, and as countries develop technologically, the need for water for industries increases.
Every industrial process (production) introduces wastes that can be harmful to the natural water system. Since the waters discharged from industrial use will be of different qualities according to the places of use, we can collect them in three main groups according to the pollutant types and loads they carry:
Production process waste: Every industry has its own specific waste water. Waste waters generated on the basis of production qualify as process wastewater. Process wastewater; It includes various raw materials, intermediate wastes and finished product wastes. Process waters contain inorganic and organic waste materials.
Cooling waters: These waters are clean and only increase the temperature of the surface waters. With the rise in temperature, two problems arise:
The solubility of oxygen in water decreases.
The increase in temperature accelerates the biological activity and causes a decrease in oxygen in the waste water.
Wastes related to workplace and employee cleaning and sanitary use: 10% of this water comes from floor washing and taps, 90% from bathrooms and toilets.
Industrial wastewater containing various chemicals has negative effects on surface waters. Therefore, it is not possible for these waters to purify themselves biologically.
It should not be forgotten that excessive use of detergents, soaps and cleaning agents in homes, materials such as waste medicine, batteries, burnt oil, together with rain water, cause ground water and surface water to be polluted.
Pollution Caused by Waste in Residential Areas
The sum of water supplied to the sewer system from human life (anthropogenic) sources is called wastewater. These are highly polluted waters where many of the scum of a settlement come together. They contain some water-soluble acids, as well as water-insoluble solids, liquids, suspensions, emulsions, and a wide variety of harmful and harmless bacteria. Such water used to be discharged into a river or a nearby lake that ran closely through the sewer system.
Bacteria, especially coli bacteria, which come from the intestines of humans and animals and are found in large numbers, are also found in domestic wastewater, which are normally harmless. Although disease-causing microbes in biological treatment plants are rendered harmless, they cannot be completely eliminated.