Water pollutant discharge standards are commonly referred to as sewage discharge standards. It is based on the water quality requirements of the receiving water body, and combines environmental characteristics and social, economic, and technical conditions to the water pollutants and harmful factors in the wastewater discharged into the environment. Control standards, or allowable emissions (concentrations) or limits of water pollutants or harmful factors. It is the basis for judging whether sewage discharge activities are illegal. Sewage discharge standards can be divided into: national discharge standards, local discharge standards and industry standards.
1. National Emission Standards National emission standards are standards formulated by the national environmental protection administrative department and applicable nationwide or in specific regions. For example, the "Integrated Wastewater Discharge Standard of the People's Republic of China" (GB8978-1996) is applicable nationwide.
2. Local Emission Standards Local emission standards are approved and promulgated by the people's governments of provinces, autonomous regions, and municipalities directly under the Central Government, and are applicable in specific administrative regions. Such as the "Shanghai Municipal Comprehensive Sewage Discharge Standard" (DB31 / 199-1997), applicable to Shanghai.
3.Industry standards At present China allows papermaking industry, shipbuilding industry, offshore oil development industry, textile dyeing and finishing industry, meat processing industry, steel industry, synthetic ammonia industry, aerospace propellant, weapon industry, phosphate fertilizer industry, caustic soda, polyvinyl chloride industry Waiting for 12 industrial categories, does not implement the national comprehensive sewage discharge standards, and can implement the corresponding industry standards.
4． Relationship between National Standards and Local Standards Article 10 of the Environmental Protection Law of the People's Republic of China states: "Provincial, autonomous region, and municipality people's governments may formulate local pollutant discharge standards for items that are not specified in the national pollutant discharge standards. For the items that have already been regulated by the pollutant emission standards, local pollutant emission standards that are stricter than the national pollutant emission standards can be formulated. "If the two standards coexist, the local standards will be implemented.
5. Relationship between comprehensive sewage discharge standards and industry standards for water pollutant discharge According to the scope of application, sewage discharge standards can be divided into comprehensive sewage discharge standards and water pollutant industry discharge standards. The "Integrated Wastewater Discharge Standard of the People's Republic of China" (GB8978-1996) and the "Shanghai Integrated Wastewater Discharge Standard" (DB31 / 199-1997) are comprehensive discharge standards. "Paper Industry Water Pollutant Discharge Standard" (GB3544--1992) is the national industry discharge standard. The national comprehensive sewage discharge standards and national industry discharge standards are not cross-implemented.
In addition, in order to ensure the safe and normal operation of the merged pipelines, pumping stations, and pretreatment facilities, and to give play to the social, economic, and environmental benefits of the facilities, the relevant departments have formulated management standards, that is, drainage households discharge sewage to urban sewers or merged pipelines Water quality control standards. For example, the Shanghai Construction Commission approved the implementation of the "Water Quality Standards for Sewage Drainage and Confluence Pipelines" in 1999 (DBJ08-904-1998). The confluent sewage mentioned in the standard refers to the sum of domestic sewage, industrial wastewater and atmospheric precipitation. The standard stipulates the maximum allowable concentration of 30 kinds of harmful substances in sewage discharge and confluence pipes. Other projects should follow the regulations in national industry and local standards. Drainage households in special industries should implement the relevant water quality standards of their industry in addition to the provisions of this standard. The Ministry of Construction of the People's Republic of China formulated the "Quality Standard for Sewage Discharge into Urban Sewers" (CJ3082--1999) in 1999, which stipulated the maximum allowable concentrations of 35 harmful substances discharged into urban sewage.
Table 1 Maximum allowable emission concentration (daily average value) of basic control items in the Standard
Note: Outside the brackets are the control indicators when the water temperature is> 12 ℃, and within the brackets are the control indicators when the water temperature is ≤12 ℃. The values before and after respectively represent the current standard value and the original implementation standard.
Table 2 Maximum allowable discharge depth (daily average) of some types of pollutants Unit: mg / L
Table 3 Select the maximum allowable emission depth (daily average) of control items Unit: mg / L
Until the latest comprehensive sewage discharge standard is issued, the latest comprehensive sewage discharge standard in 2015 will be taken as the standard. Please pay attention to the major sewage treatment equipment manufacturers or businesses.