Present situation of urban sewage treatment in China

With the rapid development of the first activated sludge as the process of the sewage plant in our country, the large-scale urban sewage plant began to operate, marking the rapid development of China's urban sewage industry. The basic treatment method of early urban sewage in our country is to trim the suburban pits and depressions, swamps or waste rivers, and to build a stable pond by dam. The traditional activated sludge method is the earliest study of sewage treatment in China, and has been applied in engineering on the basis of research. This method can obtain good effluent quality at low cost, and is the treatment process used by most of the urban sewage plants in China. The biochemical treatment process based on traditional activated sludge process, contact oxidation process, oxidation ditch process and AB process has been widely used in China because of its advantages of stable effect, easy operation and management, and low cost.

With the acceleration of China's urbanization process, the problem of urban water pollution is becoming more and more prominent, and the discharge of urban sewage shows an increasing trend. According to incomplete statistics, small and medium-sized towns account for 30% of the total urban sewage discharge.

The construction and operation of a large number of new sewage treatment plants reflects China's attention to the problem of urban sewage, and also shows the government's determination to improve the status quo of urban sewage. More than 90% of China's cities have built sewage treatment plants, as of the end of 2010, China's urban domestic sewage treatment capacity has reached 125 million m3/d, urban sewage treatment rate has reached 77.5%, in 2014, China's urban sewage treatment plants A total of more than 3,900, the daily treatment capacity of 155 million m3/d, of which 860 first-class A projects, Daily processing capacity 29.25 million m3. In recent years, Liaoning Province alone has built many sewage plants of different sizes, and the sewage has been treated to a certain extent, but the task of treating sewage is still quite heavy.

Relevant national standards for secondary sewage treatment plant effluent water quality requirements, with the "Twelfth Five-Year" energy conservation and emission reduction goals to promote, China's urban sewage treatment plant effluent water quality standards continue to improve, "urban sewage treatment plant pollutant discharge standards", urban sewage treatment plant effluent into the key river basins determined by the state and province and lakes, reservoirs and other closed, semi-closed waters, Implementation of Level 1 A standards. Due to the pressure of policy and environment, it is imperative to upgrade the standard of the municipal sewage treatment plant built in the early stage based on the traditional activated sludge process.

With the rapid development of the first activated sludge as the process of the sewage plant in our country, the large-scale urban sewage plant began to operate, marking the rapid development of China's urban sewage industry. The basic treatment method of early urban sewage in our country is to trim the suburban pits and depressions, swamps or waste rivers, and to build a stable pond by dam. The traditional activated sludge method is the earliest study of sewage treatment in China, and has been applied in engineering on the basis of research. This method can obtain good effluent quality at low cost, and is the treatment process used by most of the urban sewage plants in China. The biochemical treatment process based on traditional activated sludge process, contact oxidation process, oxidation ditch process and AB process has been widely used in China because of its advantages of stable effect, easy operation and management, and low cost.

With the acceleration of China's urbanization process, the problem of urban water pollution is becoming more and more prominent, and the discharge of urban sewage shows an increasing trend. According to incomplete statistics, small and medium-sized towns account for 30% of the total urban sewage discharge.

The construction and operation of a large number of new sewage treatment plants reflects China's attention to the problem of urban sewage, and also shows the government's determination to improve the status quo of urban sewage. More than 90% of China's cities have built sewage treatment plants, as of the end of 2010, China's urban domestic sewage treatment capacity has reached 125 million m3/d, urban sewage treatment rate has reached 77.5%, in 2014, China's urban sewage treatment plants A total of more than 3,900, the daily treatment capacity of 155 million m3/d, of which 860 first-class A projects, Daily processing capacity 29.25 million m3. In recent years, Liaoning Province alone has built many sewage plants of different sizes, and the sewage has been treated to a certain extent, but the task of treating sewage is still quite heavy.

Relevant national standards for secondary sewage treatment plant effluent water quality requirements, with the "Twelfth Five-Year" energy conservation and emission reduction goals to promote, China's urban sewage treatment plant effluent water quality standards continue to improve, "urban sewage treatment plant pollutant discharge standards", urban sewage treatment plant effluent into the key river basins determined by the state and province and lakes, reservoirs and other closed, semi-closed waters, Implementation of Level 1 A standards. Due to the pressure of policy and environment, it is imperative to upgrade the standard of the municipal sewage treatment plant built in the early stage based on the traditional activated sludge process.

The rapid development of China's sewage treatment industry is also facing many problems and challenges, which are reflected in the following aspects, ① lack of construction funds Construction of sewage treatment plants requires a lot of capital investment, so the lack of funds has become a major obstacle to limit sewage treatment. With the development of China's economy and the improvement of people's environmental protection awareness, more and more funds will be invested in the construction of urban sewage treatment plants. (2) The high operating costs of sewage treatment plants lead to a lot of equipment in sewage treatment plants. In response to this problem, the government has increased the capital investment in sewage treatment plants, but also reformed the operating mechanism accordingly, and diversified management models such as :TOT model.

The managed operation mode, BOT mode, etc., will be the future development trend of China's urban sewage treatment plant. (3) The water treated by the sewage treatment plant is discharged directly, which causes pollution of the downstream river on the one hand, and wastes the reusable water resources on the other hand. For the utilization of recycled water, China also needs to continuously introduce foreign advanced technology and develop a variety of ways. (4) Although the early construction of urban sewage treatment plants has a good effect on the removal of organic matter and suspended matter, but the removal effect of nitrogen and phosphorus is not obvious. It has not reached the current discharge standard for urban sewage in China - "Pollutant Discharge Standard for Urban sewage Treatment Plants" (GB18918-2002). At present, most sewage treatment plants in our country face the problem of upgrading standards. How to improve the removal rate of nitrogen and phosphorus nutrients has become a hot issue in the operation and control of municipal sewage plants.

The rapid development of China's sewage treatment industry is also facing many problems and challenges, which are reflected in the following aspects, ① lack of construction funds Construction of sewage treatment plants requires a lot of capital investment, so the lack of funds has become a major obstacle to limit sewage treatment. With the development of China's economy and the improvement of people's environmental protection awareness, more and more funds will be invested in the construction of urban sewage treatment plants. (2) The high operating costs of sewage treatment plants lead to a lot of equipment in sewage treatment plants. In response to this problem, the government has increased the capital investment in sewage treatment plants, but also reformed the operating mechanism accordingly, and diversified management models such as :TOT model.

The managed operation mode, BOT mode, etc., will be the future development trend of China's urban sewage treatment plant. (3) The water treated by the sewage treatment plant is discharged directly, which causes pollution of the downstream river on the one hand, and wastes the reusable water resources on the other hand. For the utilization of recycled water, China also needs to continuously introduce foreign advanced technology and develop a variety of ways. (4) Although the early construction of urban sewage treatment plants has a good effect on the removal of organic matter and suspended matter, but the removal effect of nitrogen and phosphorus is not obvious. It has not reached the current discharge standard for urban sewage in China - "Pollutant Discharge Standard for Urban sewage Treatment Plants" (GB18918-2002). At present, most sewage treatment plants in our country face the problem of upgrading standards. How to improve the removal rate of nitrogen and phosphorus nutrients has become a hot issue in the operation and control of municipal sewage plants.