Recently, the Ministry of Ecology and Environment officially issued the "Guidelines for the Preparation of Water Pollutant Discharge Control Specifications for Rural Domestic Sewage Treatment Facilities (Trial)" (hereinafter referred to as the "Working Guide"). Questions such as background, guiding principles, main content, etc. answered reporters' questions.
Q: Why is there a Work Guide?
Answer: The treatment of rural domestic sewage is an important task in implementing the strategy of rural revitalization. It is related to the comprehensive construction of a well-off society and the construction of rural ecological civilization. The Party Central Committee and the State Council attach great importance to rural sewage treatment. General Secretary Xi Jinping emphasized that it is necessary to do a good job in the construction of toilet and sewer pipe networks and rural sewage treatment according to local conditions, and continuously improve the quality of life of rural residents. The General Office of the Central Committee of the Communist Party of China and the General Office of the State Council issued the "Three-year Action Plan for the Improvement of the Rural Human Settlement Environment", which requires that "every area should distinguish drainage methods, discharge destinations, etc., and formulate classification and discharge standards for rural domestic sewage." The Ministry of Ecology and Environment actively promoted the development of rural domestic sewage treatment and discharge standards in various places. In September 2018, the “Notice on Accelerating the Development of Local Rural Domestic Sewage Treatment and Discharge Standards” was issued (Environment Office Water Body Letter  No. 1083), which clearly formulated the formulation of rural The overall requirements, control indicators, and discharge limits of domestic sewage treatment and discharge standards require localities to complete the formulation and revision of local rural sewage treatment and discharge standards by the end of June 2019.
In recent years, various regions and departments have conscientiously implemented the decision-making arrangements of the Party Central Committee and the State Council, and actively promoted the revision and revision of rural domestic sewage treatment and discharge standards. Some provinces (autonomous regions and municipalities) have issued relevant discharge standards, but in general, local rural sewage discharge standards have problems such as unclear scope of application, selection of control indicators, and unreasonable discharge limits, which have become restrictions on rural sewage treatment. Short board. In order to further clarify the requirements for the formulation of discharge standards for rural domestic sewage treatment, the Ministry of Ecology and Environment and the Ministry of Agriculture and Rural Affairs, based on in-depth investigations and extensive consultations with various parties, have compiled and issued the "Guidelines for the Control of Water Pollutant Discharge in Rural Domestic Sewage Treatment Facilities (Trial) ) ", Further clarified the determination of control standards for rural domestic sewage treatment and discharge standards, pollutant discharge limits, tail water utilization requirements, and sampling and monitoring requirements, and guided local governments to accelerate the formulation and revision of rural domestic sewage treatment and discharge standards.
Q: What are the general considerations of the Work Guide?
Answer: There are three points:
The first is to implement the decision-making arrangements of the Party Central Committee and the State Council on rural sewage treatment. The "Working Guide" thoroughly implements Xi Jinping's thoughts on socialism with Chinese characteristics in the new era, closely linked to "Strategic Plan for Rural Rejuvenation (2018-2022)", "Three-year Action Plan for the Improvement of Rural Human Settlement Environment", "Action Plan for Tackling the Battle of Agricultural and Rural Pollution", etc. Relevant requirements, promote the prevention and control of rural water pollution in China, and clarify the requirements for the control of water pollutant discharge from rural sewage treatment facilities
The second is to highlight the key points and further clarify the thinking on the formulation of emission standards. The formulation of rural domestic sewage treatment and discharge standards shall be based on the principles of rural location conditions, population concentration, sewage treatment scale, discharge destination and living environment improvement needs, in accordance with the principles of zoning, leniency, strictness, reuse, priority, practical results, and easy supervision. Classification and determination of control indicators and emission limits. The "Working Guide" further clarifies and refines relevant regulations on key issues such as the selection of control indicators and unreasonable emission limits to ensure local scientific and reasonable formulation of emission standards.
The third is to fully link the existing pollutant discharge guidance documents for rural sewage treatment facilities, and refine and refine them appropriately. The "Working Guide" is fully linked to the "Notice on Accelerating the Development of Local Rural Domestic Sewage Treatment and Discharge Standards", and according to the survey results, feedback and expert recommendations, the classification, classification, control indicators, and discharge of water pollutant discharge standards for rural domestic sewage treatment facilities
Limit values and tail water utilization make specific requirements.
Q: What are the guiding principles of the Work Guide?
Answer: One is people-oriented. With the goal of ensuring the safety of drinking water sources and improving the quality of rural living environment, through the implementation of standards, improve the quality of rural water environment and promote the construction of beautiful countryside; meanwhile, strengthen communication with the people around sewage treatment facilities and reduce society from the source. contradiction.
The second is to adapt to local conditions http://euhowblog.com/. According to rural location conditions, scale of sewage treatment and discharge destination, etc., the classification and classification of control indicators and discharge requirements are determined by zones. Under the premise of not aggravating downstream water pollution, the natural ecology, land and landscape elements in rural areas are used and considered as much as possible, and priority is given to the selection of nitrogen, phosphorus resource and tailwater utilization technologies, methods or approaches.
The third is technical feasibility. The formulation and revision of local standards should take full account of technical and economic factors and be forward-looking. Based on domestic and foreign technological levels and economic conditions, fully consider the level of pollution control that related technologies can achieve, and take into account the economic affordability and management level of rural areas.
Fourth, system coordination. The formulation and revision of local standards should take full account of existing national and international standards such as the "Emission Standards for Pollutants from Urban Sewage Treatment Plants", "Integrated Sewage Discharge Standards", "Water Quality Standards for Farmland Irrigation", "Water Quality Standards for Fisheries", "Water Quality Standards for Urban Sewage Recycling and Landscape Water" Local standards are aligned with relevant laws, regulations, plans and policies.
Q: What are the main contents of the Work Guide?
Answer: First, the technical route and format requirements for the formulation of emission standards. In accordance with the requirements of the "Technical Guidelines for the Preparation of National Water Pollutant Discharge Standards" (HJ 945.2-2018), various stages of work are mainly carried out, including environmental management needs analysis and current standard implementation assessment, rural domestic sewage treatment status analysis, and technical content determination. The format shall meet the requirements of HJ 945.2-2018.
The second is the overall requirements for pollutant emission control. It mainly includes standard classification, control index determination and pollutant emission control requirements. It can also make specific requirements for technical and management measures implemented by the standard. http://euhowblog.com/
The third is monitoring requirements and implementation and supervision. It mainly includes the setting of sampling points, determination of monitoring frequency and sampling time, and determination of pollutant measurement methods. The implementation and supervision are mainly to clarify the responsible body for the supervision and management of the implementation of emission standards, which can be determined by the people's governments at or above the county level. Water bodies with uncertain functions can be determined by the local ecological environment, agriculture and rural competent departments according to the actual conditions of the local water environment.
Fourth, the content and format requirements for the preparation of local emission standards. It mainly includes the project background, the necessity and significance of the revised standards, the revised principles and technical routes, the outline of rural domestic sewage treatment, the description of the main standards of the standards, the analysis of the technical standards for achieving the standards, the status of relevant standards at home and abroad, the analysis of the environmental benefits of implementing this standard, Standard implementation recommendations, etc. The format of preparation instructions shall meet the requirements of HJ 945.2-2018.
Q: How are pollutant control indicators considered in the Work Guide?
Answer: Through the analysis, testing and screening of the inlet and outlet water of rural sewage treatment facilities in the country, the pH value, chemical oxygen demand (CODCr) and suspended solids (SS) are used as the basic indicators for judging water quality. For BOD5 and CODCr, both of them reflect the pollution of water by reducing substances. Because of the good biochemical properties of rural sewage, BOD5 and CODCr have some correlation, but BOD5 The measurement takes a long time, CODCr is a national key control pollutant and the monitoring is convenient, so CODCr is selected as the control index.
When the ammonia nitrogen (NH3-N) content is high, it has a toxic effect on fish and other aquatic organisms, and it also harms human health to varying degrees. However, the treatment cost of NH3-N in rural sewage treatment facilities is
higher, so direct discharge of effluent NH3-N is required for treatment facilities entering Class II and III functional waters, and NH3-N for other water bodies is not compulsory for the time being. Each locality can determine it according to the actual situation. The control index TN and TP content can reflect the degree of eutrophication of the water body http://euhowblog.com/. Although the TN and TP can be removed by ecological treatment methods such as artificial wetlands, the treatment effect is unstable, and stable removal is required. It is necessary to adopt a nitrogen and phosphorus removal advanced treatment process. The scale of treatment of rural domestic sewage treatment facilities is generally small. Its sludge reflux ratio is difficult to control, the removal effect is difficult to achieve stability, and the dosage and operating costs need to be increased. Therefore, when the effluent is discharged into a closed water body or a non-standard water body with an over-standard factor of nitrogen and phosphorus, the control indicators are added with NH3-N, TN, and TP in addition to the above-mentioned basic indicators. In other cases, no compulsory requirements are imposed for the time being, and each locality can determine it according to the actual situation.
With the increasing number of rural tourism projects providing catering services, the discharge of catering wastewater has increased, and the amount of animal and vegetable oils in this type of wastewater is large. Therefore, in addition to the basic indicators above, the domestic sewage treatment facilities for rural tourism projects that provide catering services Animal and vegetable oils should be added outside.
Fecal coliform count is generally controlled as an important biological indicator. If the indicator is limited, disinfection facilities must be set up at the end of the treatment process. According to the investigation of centralized treatment facilities for rural domestic sewage in the country, it is found that even if there are disinfection facilities in a large number of technological processes, the operating costs are high and most are not in operation. Considering comprehensive technical and economic factors, at this stage, there is no mandatory requirement for the number of fecal coliform bacteria, and each locality can determine it according to the actual situation.
Chroma is an appearance indicator of water quality. For rural sewage, on the one hand, the chroma is generally low in the concentration of the influent; on the other hand, the conventional precipitation method has a good removal effect on the chroma, so the chroma No mandatory requirements for now.
In summary, the basic values were selected as pH, chemical oxygen demand (CODCr), and suspended matter (SS). Among them, the effluent is directly discharged into the surface water environment quality standards (GB 3838-2002), surface water category II and III functional waters, sea water quality standards (GB 3097-1997), second-class sea areas and ponds near villages and other environmental functions. For clear water bodies, in addition to the above-mentioned basic indicators, NH3-N should be increased; the effluent is directly discharged into surface waters of type IV and V of GB 3838-2002 and type 3 and 4 of GB 3097-1997. The pollutant control indicators are at least Basic indicators should be included. In addition to the above basic indicators, the effluent is discharged into closed water bodies, and NH3-N, TN, and TP should be added; the effluent is discharged into non-standard water bodies with nitrogen and phosphorus exceeding the standard factor. In addition to the above indicators, corresponding control indicators for the excess standard factor should be added. In addition to the above-mentioned basic indicators, domestic sewage treatment facilities for rural tourism projects that provide catering services should increase animal and vegetable oils. Various localities can increase local control indicators according to actual conditions.
Q: How are the general requirements for pollutant emission control in the Work Guide determined?
Answer: In principle, the control index value can refer to the standard concentration limit of the corresponding index in the "Emission Standard of Pollutants for Urban Sewage Treatment Plants" (GB 18918-2002), and comprehensively consider the rural location conditions, the degree of village population aggregation, the scale of wastewater generation, Factors such as discharge destination and demand for improvement of human settlements, natural landscape, total discharge control requirements of receiving water pollutants, and existing technology are determined. Sewage treatment facilities below a certain size can be appropriately relaxed in principle, but technical and management measures for standard implementation should be specified.
The effluent is directly discharged into the surface waters of Class II and III of GB 3838-2002 and Class II and III of GB 3097-1997. The corresponding control index value is not wider than GB 18918-2002-1. The concentration limit of Grade B standard, and the total amount of pollutants shall be controlled in accordance with the functional requirements of the water body. The effluent is discharged into the surface waters of Class IV and V of GB 3838-2002 and the class III and IV seas of GB 3097-1997. The reference value of the corresponding control index is not wider than GB 18918- The concentration limit of the 2002 secondary standard; where the receiving water body has TN (counted by N) control requirements, the discharge concentration limit shall be scientifically formulated by the local area according to the actual situation.
The effluent is directly discharged into a water body such as a pond near the village where the environmental function is not clear. The determination of the control index value should ensure that the receiving water body does not produce black odor. The reference value of its basic control index is not wider than the concentration of GB 18918-2002 level III standard. Limit value, NH3-N (calculated in N) is not wider than the urban black odorous water body pollution level classification standard specified in the Urban Black Stink Water Body Remediation Work Guide (Jiancheng  No. 130). value.
For effluent flowing through natural wetlands and other indirect discharges into water bodies, the reference value of its control index should not be wider than the concentration limit of GB 18918-2002 three-level standard. At the same time, effluent water such as natural wetlands should meet the pollutant discharge control requirements of receiving water bodies.
Q: What are the requirements for tailwater utilization in the Work Guide?
Answer: Nitrogen and phosphorus contained in rural sewage are nutrients needed for crop growth. After pretreatment, they can be used as resources nearby, reducing the application of fertilizers and pesticides, and reducing the risk of eutrophication of water bodies. http://euhowblog.com/ Therefore, the "Working Guide" encourages the preferential selection of nitrogen, phosphorus resource and tailwater utilization technologies, methods or approaches, and tailwater utilization should meet the corresponding national or local standards or requirements. Among them, those used for farmland, woodland, grassland and other fertilization shall meet the relevant standards and requirements of fertilization, and shall not cause environmental pollution; for farmland irrigation, the relevant control indicators shall meet the "Farmland Irrigation Water Quality Standards" (GB 5084-2005) For use in fisheries, the relevant control indicators shall meet the requirements of "Fishery Water Quality Standards" (GB 11607-1989); for landscape environment, the relevant control indicators shall meet the "Water Quality of Landscape Water for Urban Sewage Recycling" (GB / T 18921-2002). If there is a specific use situation and there is no corresponding water quality requirement for recycled water, according to the characteristics of tail water utilization, soil properties and ecological environmental protection requirements, the water quality requirements and water quality monitoring locations that tail water should meet are specified in the discharge standard.
Q: The situation in different parts of China is quite different. How can local governments adapt to local conditions in formulating emission standards, doing their best and acting within their means?
Answer: China is a vast country, with large differences in rural natural endowments and varying levels of economic development. The “Working Guide” clearly requires that the formulation and revision of emission standards should be adapted to local conditions and seek truth from facts. All localities should do their best according to factors such as rural location conditions, population concentration, sewage treatment scale, discharge destination and living environment improvement needs, natural landscapes, total pollutant discharge control requirements of the receiving water body, and existing technology levels. We will do our best to formulate scientific and reasonable emission standards. Proceed from reality, adopt applicable governance technologies, focus on practical results, and do not engage in one-size-fits-all or formalism.