Current situation and development trend of municipal sewage treatment and reuse in China

3. Oxidation ditch process

This process is called the cyclic aeration tank process, which is a delayed activated sludge treatment method of aeration, through the oxidation channel through the mixed solution between the activated sludge and the wastewater continuous circulation activity. The effluent quality of this method is relatively good, and there are fewer structures, and relatively few procedural steps in the process of operation and management.

4, urban sewage deep treatment and reuse technology

In the advanced treatment process of urban sewage, it is mainly carried out through four steps. First, the mixed water is precipitated, clarified and filtered to remove suspended matter as the main purpose. Second, the use of activated carbon adsorption method, through the huge specific surface area of activated carbon and developed microporous structure, the odor, chroma, heavy metals and organic matter in urban sewage can be removed. The results of relevant experiments show that the use of activated carbon in the treatment of sewage can effectively remove 70% of the relative molecular weight of 500-3000 organic matter. Third, the use of membrane technology to remove bacteria, reduce sewage turbidity and organic composition. The fourth step is to use advanced oxidation method to decompose macromolecular organic matter and improve the biodegradability of urban sewage. At present, the most common methods used in this step are photocatalytic oxidation, catalytic ozone oxidation, and so on. The wastewater reuse process is mainly to apply sewage to people's production and life, and the different reuse ways have different requirements for water quality.

Process water, boiler water quality and circulating cooling water quality requirements are relatively high, in general, it is necessary to combine a variety of processes to carry out in-depth treatment, and the requirements for flushing water, green water and car wash water are relatively reduced. In the process of reuse treatment, one or two combinations of processes can be adopted. The urban sewage treatment process for domestic use is mainly to carry out preliminary treatment of urban sewage through secondary treatment technology, through the comprehensive use of coagulation precipitation, clarification filtration, activated carbon adsorption depth treatment, reuse and greening, car washing and watering flowers and other life fields. The urban sewage treatment process for production purposes also requires secondary treatment technology in advance, and the comprehensive use of filtration technology, catalytic oxidation technology, microfiltration technology and reverse osmosis technology is used in production.

Third, the future development trend of urban sewage treatment and reuse in China

1, constantly update sewage treatment equipment and sewage treatment technology

At present, most of China's urban sewage treatment plants have not achieved deep sewage treatment, so there is a widespread phenomenon of low sewage recovery rate. At present, the scale of urban development is also expanding, urban living and industrial users of water is gradually increasing, the contradiction between supply and demand is becoming increasingly prominent, to solve the problem of urban water shortage, strengthen the sewage reuse capacity, deep treatment of sewage is the most important way, in the future development, should be based on improving the traditional sewage treatment technology and equipment.

2. Expand the scale of urban sewage treatment plants

In the process of urban construction and development, economic development promotes the increase of urban sewage discharge, and the original sewage treatment system is bound to increase the pressure, resulting in low sewage treatment efficiency. The large sewage treatment plant will improve the sewage treatment capacity, stabilize the water quality of the effluent, and facilitate daily management work. Therefore, the scale of sewage treatment plants will be gradually expanded in the future development. In addition, when expanding the scale of urban sewage treatment plants, special attention needs to be paid to the improvement of sewage treatment and reuse standards to provide water sources that meet the standards for urban residents' living and production.

3. Strengthen supervision and management

Sewage treatment equipment improvement and sewage treatment technology progress, but also need to do a good job of adequate management. Government departments should further improve the supervision and management ability of sewage treatment, actively organize the professional skills training of sewage treatment personnel, pay attention to improving the management ability and professional level of staff, improve the inlet and effluent detection system, use modern information technology, and strengthen the real-time supervision ability.