Pollution and self-cleaning of reservoirs

As a result of use of water for economic-household and industrial needs the considerable quantity of the sewage containing mineral and organic connections is formed. Pollution by mineral connections is usually presented in the form of sand, particles of clay, ore, slag, mineral salts, solutions of acids, alkalis and other substances.

Organic pollution on the origin is subdivided on vegetative and animal. Vegetative organic connections are the rests of plants, fruits, vegetables, cereals, papers etc. The rests of the lost animals, glutinous substances can be pollution of an animal origin physiological allocation of people and animals.

Pollution by various microorganisms concerns biological pollution, for example mushrooms, small seaweed and bacteria (as saprofitami, and parasites). This pollution arrives in a reservoir basically with household sewage and with drains of such industrial enterprises, as slaughter-houses, skinneries, factories of a preprocessing of a wool, fur, the enterprises of the microbiological industry. Besides, on a reservoir surface there can be floating substances.

Pollution Getting to a reservoir causes change physical and organolepticheskih properties of water: a transparency, chromaticity, a smell and smack. The water chemical compound as in it there are the substances changing active reaction of water and increasing the maintenance of organic and inorganic connections changes also. Pollution of an organic origin demands for the oxidation of a considerable quantity of oxygen, that, in turn, reduces the maintenance of the oxygen dissolved in water. The quantity and species of microorganisms change, and sometimes there are also pathogenic.

In reservoirs a waste of the city enterprises, fekalno-economic sewage, an atmospheric precipitation and various polluting substances washed off by them are dumped.

Pollution thus open reservoirs, underground and subsoil waters of especially big sizes has got in the capitalist countries where many rivers have turned to ditches. On them in internal reservoirs and in world ocean kitchen garbage, a dirt and waters of laundries, a hospital waste, metals and acids, mineral oil from filling stations and the airports, pesticides and mineral fertilizers from agricultural territories etc. are alloyed. It leads to death of representatives of river fauna and exhausts oxygen stocks in water.

Pollution of reservoirs worsens their sanitary condition, that, in turn, complicates use of reservoirs for the economic-household purposes and irrigatsii, causes the big damage to a fish economy, compels to develop additional actions for protection of waters from pollution.

Pollution Arriving in a reservoir is exposed to self-cleaning, i.e. To processes with which help the reservoir tries to resist to pollution to neutralise it. It is carried out by means of physical, physical and chemical, chemical and biochemical processes.

Physical processes of self-cleaning concerns razbavlenie sewage at its mixing with reservoir water that reduces concentration of arriving harmful substances. Speed of mixing of water is influenced by such factors as speed of a current, features of a channel of the river, the temperature mode, etc. Physical processes of self-cleaning depend and on dispersion of substances polluting a reservoir. So, large insoluble impurity in a gravity settle on a reservoir bottom and by that reduce concentration of pollution. sedimentatsii pollution - promote process water organisms which in the course of the ability to live take a considerable quantity of the weighed substances from water and allocate them in not digested kind. The allocated particles easily settle on a reservoir bottom.

Chemical processes of self-cleaning concern such as neutralisation, hydrolysis, oxidation, etc. For example, ions of iron, magnesium, aluminium leave from a reservoir by sedimentation formed of them gidroksidov. Thus together with them settle also salts of heavy metals. Organic polluting substances, incorporating to metals, form difficult metalloorganic complexes. All it leads to reduction of concentration of ions of heavy metals in water and to their accumulation at the bottom of a reservoir.

Biological and biochemical processes of self-cleaning occur at active participation of vegetative and animal organisms which selectively absorb separate chemical substances from river water.