Sewage treatment in China is still difficult to achieve industrial wastewater and domestic sewage collection and treatment of the whole, the separate system of initial rainwater or the combined sewer system of rainwater overflow purification treatment has not been mentioned in schedule, effective control measures and engineering measures lack City non-point source pollution system. It can be said that the pollution of the road, we are still in the way. So, in the future, the development of sewage treatment plants in the road in the end how to go? There are several questions worth discussing.

The road to pollution is still on our way

"It is still a long way off to restore the quality of the water environment to the public's expectations, and it will take at least 20~30 years of efforts to improve it overall."."

In recent years, the pollution of water environment in our country has gradually increased, and the road of pollution control has been knocking ahead. Although sewage treatment plants have been built one after another, there are still many places with serious water pollution problems. What's the reason?

China's economic and social development of the enormous pressure, various types of pollution and the coexistence of superposition, the causes of pollution is very complicated, many factors, especially the excessive concentration of population, polluting enterprises throughout the city, around the development of the stock shortage, coupled with a large number of the reservoir and dam construction, the destruction of the original terrain and environmental conditions, the influence of natural runoff, due sand transport and natural purification capacity.

The city region, in addition to sewage and industrial wastewater, and from surface runoff (especially rainwater), soil erosion, surface greening waste, garbage collection and transfer station leachate pollution. It is difficult to industrial wastewater and domestic sewage collection and treatment of the whole, the separate system of initial rainwater or the combined sewer system of rainwater overflow purification treatment has not been mentioned in schedule, effective control measures and engineering measures lack City non-point source pollution system. It can be said that the pollution of the road, we are still in the way.

Therefore, in order to restore the quality of the water environment to the public expectation, it is still a long way to go, and it will take 20 years at least ~30 years to make a comprehensive improvement. Even in developed countries, water pollution problems have not been solved completely, but their natural environment is superior, the population density is low, heavy pollution industry basically have been transferred, and the river natural runoff is abundant, water environmental capacity, the question is how to highlight its water environment.

Grade A and local emission standards are biased

"City of the sewage treatment is very important, but the current water quality index and the limit of some local discharge standards, there is a surface water quality standard of mechanical to the trend, this is not a scientific guide."

The advanced treatment of wastewater was initially designed to solve the problem of water shortage and meet the requirements of reclaimed water quality. The water resources in some areas of China are seriously insufficient, and the reuse of reclaimed water resources has dual functions, such as recycling of resources and improvement of environmental quality, and is of great significance. But the sewage reuse is a highly complex system engineering, involving policy orientation, goal orientation, water channels, quality, technology selection, security, economic benefits, public propaganda, price difference, resources and products pay more aspects of principle, there are many obstacles in the implementation of the reclaimed water utilization to to achieve desired development speed.

Therefore, it is necessary to impose severe water shortage in the city sewage treatment and utilization, the general water shortage city should be encouraged and promoted by economic means, water shortage city should actively implement to reduce water pollution load at the sewage regeneration and improve water quality function as the goal of science. Considering the economic efficiency and social benefits, the reclaimed water should be given priority for city landscape water, landscaping and ecological environment of industrial water and municipal use, water demand is relatively constant and the charge can bear, also should actively develop. While the "one size fits all" requires the regeneration of water home or the construction of decentralized residential water reclamation project, in fact, is not conducive to the healthy development of recycled water use, and even harmful.

"11th Five-Year" since, as the sewage discharge standards, the depth of processing has been widely used in urban sewage treatment plant level A dibiao reconstruction or new (expanded) project, will check the process unit as the effluent standard, but the earlier set the level A emission standard of the original intention is put forward the basic water quality of reclaimed water then the requirements directly into the emission standard is not appropriate, part of the water quality index and the limit value needs to be done to adjust relatively large, especially the fecal coliform and total nitrogen and total phosphorus index value.

The regeneration treatment of municipal wastewater is very important, but at present, the water quality indexes and limits of some local discharge standards are approaching the trend of surface water quality standards, which is an unscientific error orientation. On the one hand, the existing surface water quality standard itself has obvious defects, on the other hand, it confuses the limits and differences between the discharge standards and the water quality target (standard) of receiving water bodies. For example, excessive emphasis on the effluent COD reached 30mg/L, or even 20mg/L level, is not necessary, easy to cause significant waste; and the so-called TP0.3mg/L class IV water standard, is only suitable for good flow of rivers, for no flow or slow flow of city water, especially the reclaimed water as the main or sole replenishment the TP, at least should be less than 0.1mg/L, preferably below the level of 0.05mg/L.