Rural sewage treatment is a key area of general concern in the industry in recent years, and many enterprises have begun to layout the rural sewage treatment market on a large scale. But behind the heat, rural sewage treatment is difficult because of loud thunder and small raindrops.
At the "2019 (5th) Environmental Governance Forum", 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, pointed out that there are many factors causing this phenomenon, such as financial investment, planning and construction mode, operation and management mode, etc, Some unrealistic discharge standards have more seriously hindered the process of rural sewage treatment.
Wang Hongchen's sharing language was sharp and his views pointed to the pain points of the industry, which aroused the resonance and discussion of many guests on the scene. Xue Tao, executive director of E20 Research Institute, described Mr. Wang Hongchen's sharing with a "very good opening shot". It extended from the problems existing in sludge treatment and disposal to the problems existing in rural sewage treatment. It was profound and thought-provoking, and the brilliance was even no less than the "live debate of Chinese and beautiful anchor" on that day.
The following is Wang Hongchen's on-site sharing:
Three quarters of provinces and cities have no standards, and the lack of standards restricts rural sewage treatment
"Unreasonable, nonstandard and unscientific standards are likely to lead to the old road of sludge treatment and disposal in rural sewage treatment and fall into the embarrassing situation of standing still."
At present, there is no unified rural sewage treatment and discharge standard at the national level. Ningxia, Zhejiang, Hebei, Shanxi, Chongqing, Shaanxi, Jiangsu, Beijing and other eight provinces and cities have issued local standards, and areas that have not issued emission standards generally take the pollutant emission standard for urban sewage treatment plants (GB18918-2002) as their own reference emission standard for rural sewage treatment.
Three quarters of China's provinces and cities have not issued corresponding local standards. Without standards, there will be no boundary conditions for planning and construction, and it will be impossible to carry out planning and construction in an all-round way.
The national level has also increased the promotion of standard formulation. Last year, the Ministry of ecological environment and the Ministry of housing and urban rural development issued the notice on accelerating the formulation of local rural domestic sewage treatment and discharge standards, requiring all provinces (regions and cities) to speed up the formulation of local rural domestic sewage treatment and discharge standards, which should be completed by the end of June 2019 in principle. Where local rural domestic sewage treatment and discharge standards have been formulated, they shall be revised or improved in accordance with the requirements of this circular.
Wang Hongchen believes that this means that the state will no longer uniformly formulate national standards for a long time, and all provinces and cities will formulate appropriate local standards in combination with local specific conditions.
Recently, the Ministry of ecology and environment issued the guidelines for the preparation of water pollutant emission control specifications for rural domestic sewage treatment facilities (for Trial Implementation), which further standardized the scientific and reasonable formulation of standards by provinces and cities.
Unrealistic standards have more seriously restricted rural sewage treatment
Judging from the local emission standards that have been released at present, the emission standards formulated by some provinces are too strict and even far beyond the technical reach, which is also a problem that we have to face up to at present. At the same time, some areas without emission standards are eager to promote and simply apply the urban sewage treatment emission standards.
Wang Hongchen pointed out that "unrealistic standards have more seriously restricted rural sewage treatment".
First, the standard classification is chaotic. Some standards are classified according to the direction of drainage, but the direction of most rural sewage cannot be determined. Many rural sewage cannot be clearly explained, and the standard cannot be determined simply by classification; Some standards are classified according to the scale of facilities, but the scale depends on whether centralized or decentralized planning layout is adopted; Some standards are classified according to the local economic situation, but the local economic situation can not be determined.
Second, the emission limits are neither strict nor wide. The first level standard of many provinces is equal to or stricter than the first level a of the national urban standard, but the third level standard is relaxed to meet the standard without treatment. Wang Hongchen pointed out that the standards should be strict or loose, and the emission limits should be wide and strict.
Third, the standard elements are missing. Wang Hongchen pointed out that emission standards should include three elements: limit value, sampling method and evaluation method. However, at present, there is no clear sampling method and evaluation method for the emission standards of almost all provinces and cities. In the actual implementation process, the sampling evaluation method of instantaneous sample and full compliance is adopted.
Fourth, the formulation of standards does not consider the implementation effect or consequences“ When many standards are formulated, they do not consider the actual compliance rate, resulting in a "high or low" mentality in the implementation stage. " For example, rural receiving water bodies generally do not have water function zoning, and those with zoning will not be class IV or V water bodies. When the drainage direction is not clear, in order to be safe, prefectures, cities and counties often give priority to the most stringent standards.
Wang Hongchen pointed out that the formulation of rural sewage treatment and discharge standards needs to foresee the possible consequences in advance and whether it can achieve the corresponding treatment effect well.
Fifth, stricter and stricter standards. From the perspective of provinces and cities that have issued local discharge standards, Beijing's rural sewage discharge standards are much stricter than the class a standard for urban sewage discharge; Hebei is equivalent to level a; Shanghai is between level a and level B; Ningxia, Shanxi and Shaanxi are equivalent to class I B; Zhejiang and Chongqing are far below level I b.
Sixth, the standards for which opinions are being solicited tend to be stricter. At present, eight provinces and urban areas, including Gansu, Guangdong, Shandong, Henan, Hunan, Fujian, Hubei and Tianjin, have issued the draft of rural sewage treatment and discharge standards. Wang Hongchen pointed out that these standards for comments are generally stricter than the B standard at the urban level, and there is a trend to be stricter.
At present, many regions do not well understand the original intention of the ministries and commissions, and still do not formulate standards according to local conditions from the local reality.
Wang Hongchen believes that the provinces and cities that have issued rural sewage discharge standards or are seeking opinions, except Chongqing, are generally applying the pollutant discharge standard for urban sewage treatment plants (GB18918-2002), which is difficult for large and medium-sized urban sewage treatment plants with a capacity of 10000 tons to hundreds of thousands of tons, For the rural sewage treatment stations with dozens of tons and violent fluctuations in water quantity and quality, it is difficult to really meet the standard.
Reasonably formulate discharge standards and promote the progress of rural sewage treatment
Wang Hongchen stressed that China's rural sewage treatment and discharge standards should not be blindly high, but should proceed from the actual situation and adapt to local conditions.
He believes that when formulating standards, provinces and cities should adhere to the basic principle of seeking truth from facts, and fully consider the accessibility of process technology and operation and maintenance level according to the actual conditions in rural areas. Excessive emission standards are like "the emperor's new clothes". Rural sewage treatment should focus on controlling black odor and improving rural living environment.
The water quality indicators in the discharge standards can be mainly divided into three categories: oxygen consumption indicators, inorganic nutrition indicators and hygiene indicators. The indicators of oxygen consuming substances include organic pollution and ammonia nitrogen, which has strong process accessibility. Reducing the indicators of oxygen consumption can control the black odor; The operation of inorganic nutrition index and hygienic index depends on water quality monitoring, requires strict operation regulation, and the operation accessibility is very low. The excessive addition of phosphorus removal agent and disinfection agent is harmful to the environment, and the non-point source pollution caused by the loss of chemical fertilizer is the main source of nitrogen and phosphorus; The discharge standard of rural sewage treatment should mainly focus on oxygen consuming substances, focusing on the treatment of sanitation and black odor.
