Six kinds of sewage treatment technology

（7）With the batch activated sludge process, the sewage flows to a single reaction tank, and each process is controlled by the program according to time. In a working cycle of the reaction pool, the operating procedures are followed by inlet, reaction, precipitation, outlet and standby processes. This method is suitable for small and medium-sized water quantity and high effluent quality, which is conducive to automatic control. Through the adjustment of operation, this method can also be used for phosphorus and nitrogen removal and chemical treatment, which is conducive to sewage reuse. In recent years, SBR process has developed rapidly, especially with the development of instrument and automatic control technology and equipment, new batch activated sludge process continues to emerge, such as CASS process, CAST process, IDEA process, MSBR process and UNITANK process.

⑻AB method is the abbreviation of adsorption degradation process, which belongs to the ultra-high load activated sludge method. It is a series system of two activated sludge methods, and each of them has an independent secondary sedimentation tank. This method has strong impact load resistance and is beneficial for phosphorus and nitrogen removal and chemical treatment, especially for wastewater with high concentration and large variation of water quality and quantity. (9) Oxidation ditch The oxidation ditch is a continuous ring aeration pool, the pool is longer, shallow depth. Oxidation ditch system is a kind of treatment technology with low cost, simple structure and easy maintenance management. Its effluent quality is good, nitrogen removal can be carried out, and it is conducive to delayed aeration.

4. Biofilm metho

The sewage continuously flows through the solid filler, and a sludge scale-like biofilm can be formed on the filler. A large number of microorganisms multiply on the biofilm, absorb and degrade the organic pollutants in the water, and can play the same role as the activated sludge in purifying sewage. The dead biofilm that falls off the filler flows into the sedimentation tank with the sewage and is clarified and purified by the sedimentation tank. Biofilm has a variety of treatment structures, such as biological filter media, biological turntable, biological contact oxidation and biological fluidized bed.

(1) Biological filter biological filter is developed on the basis of the principle of soil self-purification, there are fixed fillers in the filter, the sewage flows through the filter material contact, microorganisms form biofilm on the surface of the filter material. The sewage purification plant consists of a filter bed, a water distribution system and a drainage system to provide microbial growth and habitat. Biological filter is simple to operate, low cost, suitable for small and medium-sized towns and remote areas. Biological filters are divided into ordinary biological filters, high load biological filters, tower biological filters and aerated biological filters.

(2) The biological turntable is driven by the transmission device to rotate the biological turntable at a certain speed in the contact reaction tank, and the alternating contact with the air and sewage, each cycle to complete the process of adsorption - oxygen absorption - oxidation decomposition, through continuous rotation, so that the pollutants in the sewage are constantly decomposed and oxidized. In addition to the biological turntable process, there are primary and secondary sedimentation tanks. The biological turntable has a wide range of adaptation, which can be applied to domestic sewage and various industrial wastewater. At the same time, the power consumption of the biological turntable is low, the impact load resistance is strong, and the management and maintenance are simple.

(3) Biological contact oxidation in the pool is filled with fillers, so that the oxygenated sewage is immersed in all the fillers, the filler is covered with biofilm, the sewage is in contact with the biofilm, the organic matter in the water is adsorbed by microorganisms, oxidation decomposition and conversion into a new biofilm. The biofilm that falls off from the filler is removed with the water flow to the secondary sedimentation tank, and the sewage is purified. The biological contact oxidation method has a strong ability to adapt to the impact load, the sludge production is small, and the effluent quality can be guaranteed. (4) The biological fluidized bed uses small inert particles with a relative density of more than 1, such as sand, charcoal, activated carbon, ceramic particles, etc., as a carrier, microorganisms adhere to the surface of the carrier, forming a biofilm, oxygenated sewage flows from top to bottom so that the carrier is in a fluidized body, and the biofilm is in full contact with the sewage. The treatment efficiency of biological fluidized bed is high, it can adapt to large impact load and occupy a small area.

5, natural biological treatment

The use of microorganisms growing and propagating under natural conditions to treat sewage, forming an ecosystem composed of water-microbe-plants, and conducting a series of physical-chemical and biological purification of pollutants can make full use of nutrients in sewage, which is conducive to the growth of green plants, and realize the recycling, harmfulness and stabilization of sewage. The process is simple, the construction and operation costs are low, high efficiency, is a kind of ecological principle of sewage treatment, but easy to be affected by natural conditions, occupy a large area. The main aquatic plant pond, aquatic animal pond, land treatment system and the above process combination system. The stabilization pond uses microorganisms growing naturally in pond water to treat sewage, and the photosynthesis of algae growing in the pond and the action of atmospheric oxygen supply oxygen to the pond. In the stabilization pond, the sewage stays for a long time, and its biochemical process is similar to that of natural water purification. According to the type of microbial reaction, stable ponds can be divided into aerobic ponds, facultative ponds, anaerobic ponds and aerated ponds. Land treatment takes land purification as the core, and uses soil filtration and retention, adsorption, chemical reaction and precipitation as well as microbial decomposition to treat pollutants in sewage. Crops growing on land can make full use of water and nutrients in sewage. Such as sewage farmland irrigation is a way of land treatment.