1, discharge concentration limit: for different pollutants, such as suspended solids, chemical oxygen demand (COD), biochemical oxygen demand (BOD), nitrogen and phosphorus, the upper limit of discharge concentration is usually specified;
2.pH requirements: the pH value of sewage discharge usually needs to be within a certain range to avoid the impact of acid and alkali on the environment;
3. Restriction of toxic substances: There will be corresponding restrictions and requirements on the discharge of toxic and harmful substances to ensure no harm to the environment and ecosystem;
4. Sewage treatment requirements: Paper mills usually need to be equipped with sewage treatment facilities to treat wastewater, so as to reduce the concentration of pollutants and meet the discharge standards. This may include physical treatment, chemical treatment, biological treatment and other methods;
5. Monitoring and reporting requirements: Paper mills usually need to regularly monitor and report sewage to ensure that its discharge meets the requirements of laws and regulations, and find and correct any deviation in time.
Wastewater treatment in paper mills usually includes the following steps and methods:
1. Pretreatment: Before sewage enters the treatment system, it usually needs pretreatment to remove large particles and solid suspended solids. This can be achieved by physical treatment methods, such as screens, sedimentation tanks, grids, etc.
2. Biochemical treatment: Biochemical treatment is a common sewage treatment method, which uses microorganisms to degrade organic matter. This includes activated sludge method, biofilm method, anaerobic digestion method and so on. Biochemical treatment can effectively degrade organic substances such as chemical oxygen demand (COD) and biochemical oxygen demand (BOD).
3. Advanced treatment: The sewage after biochemical treatment may need further treatment to remove residual organic matter, nitrogen and phosphorus. This can be achieved by further biological treatment and chemical treatment (such as oxidation and precipitation). ) or other advanced treatment technologies (such as membrane separation and activated carbon adsorption). );
4. Disinfection treatment: In some cases, in order to ensure that the discharged sewage does not contain pathogens and pathogenic microorganisms, disinfection treatment may be needed. This can be achieved by ultraviolet irradiation, ozone treatment, chlorine disinfection and other methods;
5. Reuse or discharge: sewage can be reused after treatment, such as cooling water and irrigation; Or meet the emission standards, and can be safely discharged into the environment.
The wastewater discharge standard of paper mill is a regulation for protecting the environment and human health. These standards usually limit and control the concentration of pollutants, pH value and toxic substances in sewage according to national and regional laws. Paper mills need to be equipped with sewage treatment facilities to reduce the concentration of pollutants through physical, chemical and biological treatment, so as to ensure the discharge up to standard. The steps of sewage treatment include pretreatment, biochemical treatment, advanced treatment and disinfection treatment. The treated sewage can be reused or safely discharged into the environment. The specific requirements and restrictions of sewage discharge standards will vary according to regional and national laws and regulations. It is suggested that paper mills should cooperate with environmental engineering experts to design a sewage treatment scheme that meets the standards.
Legal basis:
"People's Republic of China (PRC) water pollution prevention law" thirteenth.
The competent department of environmental protection of the State Council, together with the water administrative department of the State Council and the people's governments of relevant provinces, autonomous regions and municipalities directly under the Central Government, can determine the water environmental quality standards applicable to the water bodies at the provincial boundaries of important rivers and lakes according to the use functions of river basins determined by the state and the economic and technical conditions of relevant regions, and implement them after being reported to the State Council for approval.
Article 14
The competent department of environmental protection in the State Council shall, according to the national water environmental quality standards and the national economic and technical conditions, formulate the national water pollutant discharge standards.
The people's governments of provinces, autonomous regions and municipalities directly under the Central Government may formulate local standards for the discharge of water pollutants for projects not specified in the national standards for the discharge of water pollutants; For projects that have been stipulated in the national water pollutant discharge standards, local water pollutant discharge standards that are stricter than the national water pollutant discharge standards can be formulated. Local water pollutant discharge standards shall be reported to the competent department of environmental protection of the State Council for the record.
Where pollutants are discharged into water bodies with local water pollutant discharge standards, the local water pollutant discharge standards shall be implemented.