Sewage treatment plant is in a state of collapse
As for the dispute over whether the sewage treatment plant should not "send the bid", it is now very hot and spurting. More environmental protection companies have written to Chen Jining, Minister of the Ministry of Environmental Protection, saying that the current situation is "Where is the sewage plant built, where is the sewage, and where it will form a black and odorous water body.
An environmental protection company wrote to Chen Jining, Minister of the Ministry of Environmental Protection, saying that the current situation is "Where is the sewage plant built, where is the sewage? Where will the black odor water form? The standard is not improved, and the national large-scale treatment of black and odorous water may be It will become a movement that will hurt people and return to work."
The controversy surrounding the sewage treatment plant that should not be “supplied” is now in full swing in many environmental WeChat groups.
Proponents believe that the current standard is too low, the water discharged from the sewage treatment plant is still sewage, which is still dirty than the surface water, and it is difficult to meet the current environmental management requirements of China. Appeals to implement special emission limits, and even some companies advocate vigorously promoting MBR (membrane bioreactor) technology treatment process.
Opponents believe that the “selling” of emissions cannot be equated with the “standards” of water quality, and the standardization of emissions is only a way to achieve water quality compliance and management. Taking environmental quality as the core and being responsible for environmental quality is the core policy of the current government.
Sewage treatment plant "not pollution"?
It is understood that the cause of this dispute is that the Ministry of Environmental Protection is organizing the revision of the national environmental protection standard "Emission Standards for Pollutants in Urban Sewage Treatment Plants" (GB18918-2002).
The emission standards compilation group said that at present, China's urban domestic sewage, chemical oxygen demand (COD) and ammonia nitrogen emissions accounted for 67.6%, 37.6% and 57.0% of the total national emissions, respectively, to strengthen the urban domestic sewage. Emission control plays an important role in improving the quality of the water environment.
China's urban sewage treatment started in the late 1970s and grew rapidly after 2000. The state and local governments at all levels have continuously increased investment in the construction and renovation of urban sewage treatment plants. According to the data of the Ministry of Housing and Urban-Rural Development, as of the end of June 2015, the city-wide cities and counties (hereinafter referred to as towns, excluding other towns) have built 3,802 sewage treatment plants, and the sewage treatment capacity has reached 161 million cubic meters per day. Among them, there are about 860 Grade A projects with a daily processing capacity of 29.25 million cubic meters. Among them, more than 3,000 sewage treatment plants have not reached the Class A emission standard.
According to the 2014 Annual Environmental Statistics Report released by the Ministry of Environmental Protection in June last year, the national sewage treatment plants in the country handled 38.27 billion cubic meters of sewage, up 5.9% year-on-year, and the urban sewage treatment rate reached 90.2%.
According to the compilation group, with the continuous growth of China's population and the improvement of urbanization level, urban domestic sewage discharge will continue to increase. It is expected to reach about 60 billion tons by 2030, which is 1.6 times of the current level. According to the current emission control level, The COD and ammonia nitrogen emitted from urban domestic sewage will increase by about 33% in 2030. Therefore, the management of urban domestic sewage discharge needs to be further emphasized and strengthened.
“There are too few pollutant control projects in the current standards.” “In addition to conventional pollutants such as COD and ammonia nitrogen, the problem of heavy metals and toxic and harmful pollutants in wastewater discharge cannot be ignored because China's urban sewage treatment plants also partially accept industrial wastewater. Said the team.
Before the two sessions this year, some media issued the article "Why the sewage treatment plant does not control pollution", saying that "the sewage treatment plant with pollution control as its own duty has become a large sewage discharger." The article analyzes that the direct cause is the operation of these sewage treatment plants. There is a problem with supervision.
According to the article, for example, according to the current “Emission Standards for Pollutants in Urban Sewage Treatment Plants”, the maximum allowable level of COD emission is up to 50-120 mg/L, but this requirement is far lower than the national standard for surface water – three categories. The maximum concentration of water COD is 20 mg / liter, even if it is regarded as dirty surface five types of water, its COD concentration can not be higher than 40 mg / liter. That is to say, the large amount of sewage discharged by the sewage treatment plant can still exceed the inferior five types of water that people expected. The article calls for "the fundamental strategy is to improve the pollutant discharge standards of sewage treatment plants according to the new requirements for promoting the construction of ecological civilization. At the same time, the iron surface is selfless and strictly regulated."
After that, an environmental protection company sent a letter to the Minister of Environmental Protection Chen Jining, saying that the current situation is "Where is the sewage plant built, where is the sewage? Where will the black odor water form? The standard is not improved, and the large-scale treatment of black and odorous water in the country. I am afraid that the action will become a campaign for the loss of money and labor." And that if the urban sewage treatment can reach the "special emission limit (the main indicator is equivalent to the surface water class IV standard)", it will be converted into usable water resources. It is an important support for the construction of a national water security strategic system and the promotion of the ecological civilization of “Landscape Lakes and Lakes”.
At present, the total discharge of pollutants has far exceeded the carrying capacity of water environment capacity. The effluent of existing wastewater treatment plants is controlled according to the national first-class A standard, and still belongs to the inferior five categories (redox potential is less than -200～50mv, ammonia nitrogen is 8～15mg). /L) is one of the main sources of black odorous water in the city. The introduction of the new standard is a catalyst for the innovation and upgrading of the supply side, which can completely reverse the unfavorable situation of building a sewage plant into a new source of pollution.
Sewage treatment requires "force at both ends"
However, experts such as Xia Qing, former vice president and chief engineer of the Chinese Academy of Environmental Sciences, hold different views.
Xia Qing is an expert in the fields of environmental planning, environmental standards and environmental signs. He presided over the water pollution prevention and control plans of the five major river basins such as the Yangtze River and the Yellow River. He served as the general manager of the pollution control planning technology of the Huaihe River, Taihu Lake and the South-to-North Water Diversion Project, and participated in the revision. National surface water environmental quality standards.
In the past few days, Xia Qing has issued three questions about the article, saying that "whether the sewage treatment plant is not polluting" is a "qiwen". Xia Qing believes that the title of "why the sewage treatment plant does not cure pollution" is to slap the hat. In fact, “in the past 20 years, the total amount of water pollutants in the country has been reduced, basically on the shoulders of sewage treatment plants.”
Xia Qing believes that emission standards and quality standards cannot be confused. “Even if the sewage treatment plant effluent is up to the surface water standard according to the 24 items of surface water index, it is also the reclaimed water of the sewage plant, not the surface water. What is the use of reclaimed water? In addition to safety and health factors, the emotional factors of the people must also be considered.”
Xia Qing said that raising emission standards is not a cure-up policy. The emission standards cannot be tightened at will. He said that China's two types of two-level Chinese environmental standards system established in the 1980s stipulated that quality standards are based on the protection of aquatic organisms and human health, and emission standards are based on technical and economic feasibility. National standards are national, local standards reflect local characteristics and are stricter than national standards. In such a large system, emission standards are only one part of the large system of water pollution control.
"The correct emission standards must be in the large-scale system decision-making of water pollution control, reflecting the technical and economic feasibility of the country, and promoting the use of multiple environmental management methods. It is necessary to oppose arbitrary tightening of emission standard limits and engage in a special limit to seize. EIA, planning, and especially the enforcement space for pollutant discharge permits."
Xia Qing said that the national sewage treatment plants are required to achieve surface water requirements, and not to mention the difference between surface water and reclaimed water, only to discuss blindly raising the national sewage law enforcement bottom line, so that it is enough for the common people to pay more. Because the conditions that can use the environmental capacity to reduce investment have been abandoned, the difference in investment in water quality management targets in different functional areas has been neglected, and the water fee that can save the common people to meet the same water quality standards still needs people to come out.
"Of course, there are many regrets and hidden dangers in China's sewage treatment industry." Qu Jiuhui, an academician of the Chinese Academy of Engineering and a researcher at the Research Center for Eco-Environmental Sciences of the Chinese Academy of Sciences, said that the sewage treatment industry has gone from top-level design to concrete practice, and the lack of sustainable development concepts has led to the industry's Short-sighted, extensive, chaotic, and even inferior.
Wang Kaijun, a professor at Tsinghua University and deputy dean of the School of Environment, said that most of China's sewage treatment plants have eliminated the design of primary sedimentation tanks, and have adopted a large number of high-energy processes such as delayed aeration to achieve pollutant reduction and emission reduction at the expense of high energy consumption. The embarrassing situation of “reducing pollutants and increasing greenhouse gas emissions” has been formed.
At the end of last year, water treatment company Xylem released a new study at the 10th China International Conference on Urban Water Development, saying that using existing sewage treatment technology to improve energy efficiency, the relevant CO2 emissions can be reduced by half. The study surveyed the wastewater treatment industry in the three major regions of the United States, Europe and China and found that about 50% of electricity-related emission reductions can be achieved without increasing costs or reducing costs. It reached 13 million metric tons.
Lu Shuping, president of Xylem China, said, “We have found that China has a high probability of return on investment and emission reduction. In China, almost 100% of emission reductions are achieved without increasing costs or reducing costs. And the annual emission reduction of carbon dioxide equivalent is expected to reach 13 million metric tons."
Xia Qing believes that if the sewage treatment plant is really required to raise the standard, it will no longer be able to work hard at the terminal, so that the hats of the top ten polluting industries will remain in the sewage treatment plant. It is necessary to work under the separation of the front-end source, from the excrement of urine to the sewage treatment plant, and to use the strategic measures of the green and large circulation of urban and rural nutrients to share the pressure for the sewage treatment plant. “Simple pressure sewage treatment plant is the practice of whipping fast cattle.”
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