Belongs to the secondary processing wastewater biochemical treatment, to remove heavy suspended solids and solubility biodegradable organic matter as the main goal, the process form is varied, can be divided into activated sludge method, AB method, method of A/O and A2 / O process, SBR, oxidation ditch, stabilization pond method, land treatment method and so on the many kinds of processing methods.
Most municipal wastewater treatment plants adopt activated sludge method.
The principle of biological treatment by biological effect, and, in particular, the role of microorganisms, to complete the decomposition of organic matter and biological synthesis, transform organic pollutants into harmless product gas (CO2), liquid (water) and solid products that are rich in organic matter, microbial groups or biological sludge);
The superfluous biological sludge is separated from the sedimentation tank in the sedimentation tank and removed from the purified sewage.
In the process of wastewater biochemical treatment, the factors that affect microbial activity can be divided into two categories: matrix and environment.
The matrix class includes nutrients, such as carbon source material, nitrogen source, phosphorous source and other nutrients, as well as trace elements such as iron, zinc and manganese.
In addition, some toxic and harmful chemicals such as phenol and benzene are also included, including some heavy metal ions such as copper, cadmium and lead ions.