There is a lot of waste water now. Some industrial waste water, if not properly treated, is likely to cause environmental pollution. Many water treatment companies currently use many methods to treat water Activated carbon The portal website introduces activated carbon decontamination skills for reference in the water treatment industry.

1. Activated sludge method. Activated sludge process is widely used in urban domestic sewage treatment. It is a biological treatment process applied in the world, with the advantages of high treatment capacity and good effluent quality. The method is mainly composed of aeration tank, sedimentation tank, sludge return and excess sludge discharge system. The waste water and the returned activated sludge enter the aeration tank together to form a mixed liquid. The aeration tank is a bioreactor, which is filled with air through the aeration equipment. The oxygen in the air dissolves into the mixed liquid to produce aerobic metabolic reaction, and the mixed liquid is stirred enough to be suspended. In this way, the organic matter and oxygen in the wastewater can fully contact with the microorganisms and react. Then the mixed liquid enters the sedimentation tank, and the suspended solids in the mixed liquid settle down in the sedimentation tank and separate from the water. The purified water flows out of the sedimentation tank. Most of the sludge in the sedimentation tank returns, which is called return sludge. The purpose of return sludge is to maintain a certain concentration of suspended solids in the aeration tank, that is, to maintain a certain concentration of microorganisms. The biochemical reaction in the aeration tank causes the proliferation of microorganisms, which are usually discharged from the sedimentation tank to maintain the stable operation of the activated sludge system. This part of sludge is called excess sludge. In addition to the ability to oxidize and decompose organic matter, the activated sludge should also have good coagulation and sedimentation performance, so that the activated sludge can be separated from the mixed liquid to obtain clear water. As sewage treatment is a project focusing on environmental and social benefits, it is often limited by funds in the process of construction and actual operation, making the problem of treatment technology and funds become the "bottleneck" of water pollution treatment in China. To sum up, the common problems in the field of urban domestic sewage treatment and application are:

1. The traditional activated sludge method is often characterized by high capital construction and operation costs, large energy consumption, complex management and easy sludge bulking; The equipment cannot meet the requirements of high efficiency and low consumption.

2. With the continuous strictness of sewage discharge standards, the discharge requirements of nitrogen, phosphorus and other nutrients in sewage are high. The traditional sewage treatment process with nitrogen and phosphorus removal function is mainly activated sludge process, which often requires multiple anaerobic and aerobic reaction tanks in series to form a multi-stage reaction tank. The purpose of nitrogen and phosphorus removal is achieved by increasing internal circulation, This will inevitably increase the cost of infrastructure investment and energy consumption, and make the operation management more complex.

3. At present, the treatment of urban sewage is mainly centralized treatment, and the investment in the huge sewage collection system is far more than the investment in the sewage treatment plant itself. Therefore, building a large sewage treatment plant to centrally treat domestic sewage is not necessarily an available scheme from the perspective of sewage recycling. Therefore, how to make the urban sewage treatment process develop towards the sustainable direction of low energy consumption, high efficiency, less excess sludge, convenient operation and management, and the realization of phosphorus recovery and treated water reuse has become a common concern in the current water treatment technology and application fields. This requires that sewage treatment should not only meet the requirements of single water quality improvement, but also take into account the recycling and energy utilization of sewage and contained pollutants, and the technology used should be based on the premise of low energy consumption and low resource consumption.

2. Biofilm method. In the development and application of wastewater biological treatment, activated sludge and biofilm have always played a leading role. The biofilm method is mainly used to remove dissolved organic pollutants from wastewater. The main feature is that microorganisms attach to the surface of the medium "filter material" to form a biofilm. After the sewage contacts the biofilm, the dissolved organic pollutants are absorbed by microorganisms and converted into H2O, CO2, NH3 and microbial cell substances. The sewage is purified, and the required oxidation is generally directly from the atmosphere. The biofilm treatment system is suitable for the treatment of small and medium-sized urban wastewater. The treatment structures used include high load biological filter and biological rotary table, and the biological filter is more suitable in southern China. With the development of new fillers and the continuous improvement of supporting technologies, the biofilm process developed in parallel with the activated sludge process has developed rapidly in recent years. The biofilm process has the advantages of high treatment efficiency, good shock load resistance, low sludge production, small floor area, easy operation and management, and is competitive in treatment.

3. Oxidation is one of the most widely used and potential pretreatment methods for urban domestic sewage. According to the types of oxidants and reactors, oxidation methods can be divided into chemical oxidation, catalytic oxidation, (catalytic) wet oxidation, photocatalytic oxidation, supercritical oxidation, etc. Although the chemical oxidation method is simple to operate, its treatment effect is not very ideal, and its operation cost is high, so it is not used in many urban domestic sewage treatment applications. In order to improve the treatment effect and reduce the operation cost, some other oxidation technologies have been developed. The photocatalytic oxidation method has simple equipment, mild operating conditions, strong oxidation capacity, strong sterilization and thorough treatment. Therefore, it has an excellent application prospect in the advanced treatment of water and the treatment of organic wastewater that is difficult to biodegrade