Sewage: cleaning methods

Everyone knows that humanity can not live without water. Millions of cubic meters of life-giving moisture are consumed daily, however, sewage is unsuitable for simply dumping into natural water bodies. Therefore, their preliminary cleaning and disinfection is necessary. This set of measures forms a stable operation of the water supply system.

Sewage is waste water, as well as atmospheric runoff, whose characteristics have deteriorated under the influence of human activity and which enter the reservoirs through the sewage system or by gravity.

The classification of wastewater has a fairly simple structure:

1. By chemical composition.

2. By place of education.

3. By the nature of the contamination.

Sewage in chemical composition is divided into three groups: organic (vegetation and its products), mineral (clay, sand, insoluble salts) and biological (bacteria, fungi, viruses).

At the place of formation, atmospheric and domestic wastewater are released. In addition, as already mentioned, the contaminants can be of a different nature, for example, soluble, insoluble and colloidal substances.

By the degree of contamination, wastewater is characterized by some generalized indicators, such as the chemical and biochemical oxygen demand, the number, the concentration of hydrogen ions, and also the suspended and settling substances and the dry residue.
There are several ways to clean up waste water, the main ones of which are mechanical, chemical and biological methods. Each of them has its own peculiarities, however, the most common cases are when not one, but several methods are applied at once. This makes it possible to form a whole complex of treatment facilities. Let's consider each method in more detail.

Mechanical cleaning method

As a result of this treatment, waste water is passed through a system of filters that trap and trap large particles. This stage is called rough cleaning. Next comes another filter system, which is designed to trap smaller particles. Then the water enters the special chambers, where the clarification process takes place.

Chemical cleaning

Since during use, wastewater is exposed to all kinds of organic and inorganic substances and compounds, as well as other chemical reagents, then in order to discharge the waste water into a natural body of water, it is necessary to carry out the neutralization process. Such measures are carried out on the basis of oxidation-reduction reactions. For example, if it is necessary to remove impurities caused by acid solutions, the wastewater is treated with alkalis, and vice versa.

Biological method

It means the purification of waste water from various organic impurities. The presented technique implies the presence of a special kind of bacteria, which, in turn, process organic compounds, which contributes to their decomposition and removal from purification systems. This method can take place when interacting with oxygen or without it. Hence, aerobic and anaerobic cleaning are distinguished.