Introduction of biological sewage treatment methods

Aerobic biological treatment

Under aerobic conditions, the wastewater treatment process that depends on the biochemical action of aerobic bacteria and facultative aerobic bacteria is called aerobic biological treatment.  The method requires a supply of oxygen.  According to the state of aerobic microorganisms in the treatment system, it can be divided into activated sludge method and biofilm method.

A. Activated sludge process is the most widely used biological treatment method at present.  This method is rich in organic pollutants in the aeration tank with bacteria in waste water factory constantly air (aeration), after a certain amount of time will appear suspended state of flocculent mud particle, it is actually made up of aerobic bacteria (and facultative aerobic bacteria) by adsorption of organic matter and bacteria metabolic activity of the product of the aggregate, have a strong ability to break down organic matter,  This is called activated sludge.

After the mixed solution of sewage and activated sludge from the aeration tank is separated by sedimentation tank, the clarified water is discharged, and the sludge is returned to the aeration tank as seed mud, and the operation continues.  This biological treatment with activated sludge as the main body is called activated sludge process ".  About 90% of organic matter in the wastewater can be removed by staying in the aeration tank for 4 ~ 6h.  The activated sludge process has a variety of tank types and operation modes, usually including ordinary activated sludge process, fully mixed surface aeration method, adsorption regeneration method and so on.

Anaerobic biological treatment

In the absence of oxygen, the use of Anaerobic Microorganisms to decompose the organic matter in sewage, sewage purification method called anaerobic biological treatment.  In recent years, the world's energy shortage, so that the sewage treatment to energy-saving and realize the direction of energy development, thereby promoting the development of anAerobic microbial treatment methods.

A large number of efficient new anaerobic bioreactors have appeared successively, including anaerobic biological filter, upflow anaerobic sludge bed, anaerobic vulcanization bed and so on.  Their common characteristic is high concentrations of biological groups in the reactor, sludge age is very long, thus greatly improve the processing ability, which makes anaerobic biological treatment of small energy consumption, can be recycled energy, less surplus sludge quantity, sludge generated a stable and easy to handle, on the high concentration organic wastewater treatment efficiency higher advantages fully reflect.  After years of development, anaerobic biological treatment has become one of the main methods of sewage treatment.