Biological Sewage Treatment

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Biological Sewage Treatment


a method of purifying domestic and industrial sewage, consisting of biochemical decomposition (mineralization) by microorganisms of organic substances (impurities of organic origin) dissolved and emulsified in sewage. Microorganisms (bacteria) use these substances as sources of food and energy for their life processes. In the process of the microorganisms’ respiration, organic substances are oxidized and energy necessary for their life functions is released. Part of this energy is used for the processes of synthesizing cellular substances, that is, for increasing the mass of bacteria, the quantity of active sludge, and the thickness of the biologic film in the purifying structures. Bacteria that participate in the mineralization of organic compounds in sewage may be divided into two groups, according to their relationship to oxygen: aerobes (which use oxygen dissolved in water for respiration) and anaerobes (which develop in the absence of free oxygen). Besides dissolved organic substances, sewage contains suspended substances, tars, and oils, which must be removed before biologic treatment. For this purpose, gratings, sand traps, and settling tanks are used. Aerobic biological purification is accomplished under conditions close to natural ones, in irrigation fields and filtration fields and in biologic ponds; and, when the life processes of the microorganisms become intensified, in an artificially created environment, in aerotanks, aerofilters, and biofilters. In the anaerobic method of purification, methane tanks are used. Choice of the type of structure is determined by the character and quantity of the sewage, local conditions, requirements as to quality of the purified sewage, and so on. As a result of complete purification, biochemically oxidized organic substances are virtually absent from the water. The water loses its ability to putrefy and becomes transparent, and bacterial contamination is significantly decreased. Biologic treatment is only used for sewage containing a sufficient quantity of biogenic elements (nitrogen, phosphorus, potassium) necessary to the life processes of microorganisms. In a number of cases, biogenic elements are added to sewage before biologic treatment, in the form of salt solutions.


Kanalizatsiia, 4th ed. Edited by A. I. Zhukov. Moscow, 1969.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
Mentioned in ?
References in periodicals archive ?
One project involves the construction of 53 holiday homes, each with a swimming pool and three biological sewage treatment plants, and the other involves a five-star hotel, eight storeys tall and containing 168 rooms.
In Hong Kong SAR, Black & Veatch has secured several key projects, which include the investigation study of expansion of the Tai Po Water Treatment Works from 250 to 1200 MLD;the feasibility study of using the space below a future freight yard to accommodate part of a future biological sewage treatment plant on Stonecutters Island; and investigation, design and construction of village sewerage schemes in the North District, Tseung Kwan O and Tuen Mun of Hong Kong.

Full browser ?