Domestic sewage treatment refers to the discharge of sewage discharged from the daily life of residents after treatment to meet the sewage discharge standard. Mainly from residential buildings and public buildings, such as residences, institutions, schools, hospitals, shops, public places and industrial enterprise toilets. The pollutants contained in domestic sewage are mainly organic matter (such as protein, carbohydrates, fat, urea, ammonia nitrogen, etc.) and a large number of pathogenic microorganisms (such as parasite eggs and intestinal infection viruses, etc.). The organic matter present in the domestic sewage is unstable and easily corroded to produce foul odors. Bacteria and pathogens multiply with organic matter in domestic sewage as nutrition, which can lead to the spread of infectious diseases.
Processing technology
The core of domestic sewage treatment is the biochemical part, and the main process includes biological contact oxidation method and MBR membrane method.
Process one:
Biological contact oxidation method is a kind of aerobic biofilm method, which is improved and evolved from contact aeration method on the basis of biological filter, so it is also called "submerged filter method" and "contact aeration method". method" and "submerged biofilm method", etc.
Process two:
Membrane bioreactor (MBR for short) is a new type of sewage treatment and reuse process that combines biodegradation and membrane separation technology. It uses membrane separation equipment to intercept the activated sludge and macromolecular substances in the biochemical reaction tank, saves the secondary sedimentation tank and mechanical filtration, and improves the separation efficiency of mud and water; through the interception of the membrane, the suspended solids are completely trapped in the biological reaction tank. , improve the effluent quality, and at the same time, the concentration of activated sludge is greatly increased, and the hydraulic retention time (HRT) and sludge retention time (SRT) can be controlled separately, which improves the efficiency of biochemical treatment. Reaction and degradation help to reduce excess sludge production (even achieve zero sludge discharge) and reduce sludge treatment costs.
Summarize
Domestic sewage treatment generally determines the degree of sewage treatment and the corresponding treatment process according to the utilization or discharge of sewage and considering the natural purification capacity of the water body. The treated sewage, whether used in industry, agriculture or recharge to supplement groundwater, needs to meet the relevant water quality standards issued by the state.