Urban water environment is the most affected and important water environment for human beings. However, looking at the current situation of China's water environment, it is not difficult to find that there is still much room to improve the overall water quality. The water environment of major cities such as Beijing, Shanghai, Wuhan and Guangzhou is not optimistic“ There is no good top-level design for urban water environment treatment in China, which is the key to restricting the current water environment treatment. " At the 2017 (9th) Shanghai water industry hot spot forum, Professor Wang Hongchen, vice president of the school of environment of Renmin University of China and director of the low carbon water environment technology research center of Renmin University of China, said that starting from the three key problems existing in the current urban water environment governance, he put forward several summary suggestions for urban water environment governance, which brought great inspiration to the participants.
The following is the content shared by Professor Wang Hongchen on site (sorted according to the on-site speech and not reviewed by me):
There is still no top-level design for urban water environment treatment in China
Professor Wang Hongchen pointed out that there are many action plans related to water pollution control in China.
A long time ago, we made water pollution prevention and control plans for key river basins, as well as action plans for clean small river basin treatment, comprehensive treatment of river basin water pollution, good lake protection, continuous comprehensive treatment of rural environment, treatment of urban black and smelly water bodies and construction of sponge cities. However, we must face up to a problem. What is the top-level design for water environment treatment? At present, there is no clear statement.
Professor Wang Hongchen pointed out that the United States made a detailed top-level design for urban water environment treatment in the 1970s. In 1972, the United States changed the water pollution prevention and Control Act into the water purification act. The legislative goal of the water purification act mentioned that the national water quality goal of fishing, swimming and hunting could be achieved before 1983. In the later revised Act, it was made clear that the groundwater quality goal is the quality standard of drinking water, that is, every drop of water underground in the United States can be taken out for drinking at any time. This is the overall goal and top-level design of water environment governance in the United States.
The above picture is the publicity picture of the water purification act of the United States. American water bodies can drink, swim and fish, which is the right of the public. From the above, it can be seen that the whole water environment treatment in the United States has a clear top-level design.
In China, although a lot of work has been done, a number of action plans have been formulated, and the comprehensive process of water pollution prevention and control has been greatly promoted, there is still a lack of top-level design.
Professor Wang Hongchen pointed out that the urban water system includes urban water supply system, urban sewage system, urban rainwater system and urban water environment. The water supply system is relatively independent, so the problem of urban water system is mainly reflected in the interweaving of urban rainwater system and sewage system, which highly interferes with and affects the urban water environment.
The problem of urban water environment treatment mainly focuses on several points: first, what kind of urban water environment do we want? From the perspective of quality, there are highly different opinions, such as no black and odorous, fishing and swimming, harmony between people and water, and the classification of surface water quality V, IV and III. From the perspective of volume, how large is more appropriate? There are no clear guidelines. At present, there is no basic top-level design of quality and volume. How to determine the discharge standard of sewage treatment without knowing the volume and quality of water environment?
Second, the problem of rainwater treatment. Professor Wang Hongchen said that rainwater needs to be quickly removed, but rainwater needs to be treated, and the treatment will seriously affect the rapid removal. When we realize the importance of rainwater treatment, new problems arise, such as how should rainwater be treated? What should be the depth of processing? Is it treated separately or in a sewage treatment plant? wait.
Professor Wang Hongchen stressed that without a top-level design on urban water environment, it is difficult to get answers to these questions.
Three key points of top-level design for urban water environment treatment
Based on the above considerations, Professor Wang Hongchen focused on three key issues in the top-level design of urban water environment treatment.
First Build a scientific evaluation system of urban water environment.
Professor Wang Hongchen said that we should first sort out the relationship between surface water environmental quality, pollution degree and water function zoning. He summarized and introduced that at present, there are mainly five relevant laws and regulations, including environmental quality standards for surface water (GB3838-2002), environmental quality assessment methods for surface water (HB [2011] No. 22), categories and codes of surface water environmental functional areas (hj522-2009), management methods for water functional areas (Shui yuan [2003] No. 233) Measures for the supervision and administration of water functional areas (water resources [2017] No. 101).
If the standards set by these laws and regulations are used to evaluate the urban water environment, we can clearly see that the standard requirements for urban water environment quality in China are extremely strict.
The environmental quality standard for surface water (GB3838-2002) (hereinafter referred to as "water environmental quality standard") consists of 24 main indicators. It can be seen from the table below that the water environmental quality standard actually divides water into 5 categories and 6 grades, and the first category is mainly applicable to source water and national nature reserves; Class II water is mainly applicable to the first-class protection area of surface water source of centralized domestic and drinking water, habitat of rare aquatic organisms, spawning ground of fish and shrimp, feeding ground of larvae and juveniles, etc; The third category is mainly applicable to fishery waters and swimming areas such as centralized domestic and drinking water surface water source secondary protection area, fish and shrimp wintering ground, migration channel and aquaculture area; The fourth category is mainly applicable to general industrial water areas and entertainment water areas in which human body is not in direct contact; Class V water is mainly applicable to agricultural areas and water areas with general landscape requirements.
Professor Wang Hongchen pointed out that in the United States, water functions and standards are basically divided into five categories, but the United States puts agricultural water at a higher water quality standard, and the five categories of water are only applicable to industrial water. Class I water is used as a source of drinking water, not for nature reserves.
