The principle of biological treatment is to complete the decomposition and synthesis of organic matter through biological action, especially the action of microorganisms, and transform organic pollutants into harmless gas products (CO2), liquid products (water) and solid products (microbial communities or biological sludge) rich in organic matter; Excess biological sludge is separated from solids and liquids in the sedimentation tank and removed from the purified sewage.
Extended data:
Sewage treatment process is divided into three levels:
Primary treatment: physical treatment, mechanical treatment, such as grid, sedimentation or air flotation, to remove stones, sandstone, fat and grease from sewage.
Secondary treatment: biochemical treatment, in which pollutants in sewage are degraded and converted into sludge under the action of microorganisms.
Tertiary treatment: advanced treatment of sewage, including removal of nutrients and disinfection of sewage by chlorination, ultraviolet radiation or ozone technology. Perhaps according to the different treatment objectives and water quality, some sewage treatment processes do not include all the above processes.
References:
Baidu encyclopedia-sewage treatment plant