1, the primary treatment of sewage is also called physical treatment of sewage. Through simple sedimentation, filtration or proper aeration, suspended solids in sewage can be removed, pH value can be adjusted, and the degree of corruption of sewage can be reduced. The treatment can be composed of screening, gravity precipitation, flotation and other methods in series, which can remove most particles with particle size above 100 micron. Screen filtration can remove larger substances; Gravity precipitation can remove inorganic particles and viscous organic particles with relative density greater than 1; Flotation can remove particles (oil, etc.) ) The relative density is less than 1. After primary treatment, wastewater generally still can't meet the discharge standard.
2. Secondary treatment of sewage: After primary treatment, the sewage is treated by aeration tank and activated sludge sedimentation tank to further purify the sewage. Biological method and flocculation method are commonly used. Biological method is to use microorganisms to treat sewage, mainly to remove organic matter from sewage after primary treatment; Flocculation method is to destroy the stability of colloid by adding flocculant, so that colloidal particles flocculate to produce floc and adsorb, mainly to remove inorganic suspended solids, colloidal particles or low-concentration organic matter from sewage after primary treatment. After secondary treatment, sewage can generally meet the requirements of agricultural irrigation and sewage discharge standards. However, under certain conditions, it may still cause pollution of natural water bodies.
3. Tertiary treatment of sewage (also called advanced treatment): After secondary treatment, other pollutants in sewage are further removed (for example; Nitrogen, phosphorus, fine suspended solids, trace organic matter and inorganic salts. ). The main methods are biological denitrification, agglutination precipitation, sand filtration, diatomite filtration, activated carbon filtration, evaporation, freezing, reverse osmosis, ion exchange and electrodialysis.
Sewage treatment is divided into three levels: primary treatment, physical methods such as filtration and precipitation to remove pollutants in water.
Secondary biochemical treatment, using microorganisms to decompose pollutants dissolved in water from water.
Three-stage fine treatment, using reverse osmosis membrane, ultrafiltration and other means to carry out advanced treatment of biochemical effluent, and discharge or reuse it after reaching the standard.
How to classify sewage treatment? How many levels does a * * * have? Vito Environment10000V team will answer your questions.
Sewage treatment can be divided into primary treatment, secondary treatment and tertiary treatment (advanced treatment) according to the degree of treatment.
The primary treatment mainly removes large suspended solids from water by physical action, which mainly includes: coarse grid-fine grid-grit chamber-primary sedimentation chamber. The coarse grid mainly intercepts large floating objects, prevents blocking the subsequent structures, and reduces the processing load. Fine mesh is similar to coarse mesh, but the filtering level is finer. The grit chamber mainly removes sand from water to reduce the abrasion of sand to subsequent equipment. In addition, sometimes sand particles will attach a lot of organic matter, and grit chambers are often used to connect grit chambers. The primary sedimentation tank is mainly used to remove the precipitable suspended solids in sewage. After passing through the primary sedimentation tank, the organic matter in the water can be removed by about 30%-40%.
Secondary treatment is mainly biochemical treatment of sewage after primary treatment, including biological reaction tank and secondary sedimentation tank.
The biological reaction tank is different due to different processes, but its main function is to convert organic matter in water into carbon dioxide, water and nitrogen through biochemical action or be absorbed by organisms into precipitable sludge. The secondary sedimentation tank is mainly used to precipitate activated biological sludge after complete biochemical reaction and remove pollutants. After secondary treatment, the removal rate of pollutants can reach about 80%-90%.
Tertiary treatment, also known as advanced treatment, is mainly used for sewage recycling, that is, sewage is reused after treatment. According to the reuse standard, the advanced treatment process is different. The general process includes coagulation-filtration-disinfection, which is basically similar to the water treatment process.
The level of sewage treatment is determined according to the discharge standard and reuse standard, but ordinary urban sewage treatment plants are not allowed to discharge only after primary treatment, because the sewage after primary treatment basically can not meet the sewage discharge standard, and only some sewage treatment plants in coastal cities reached the lower standard of deep-sea discharge standard in early construction, adopted primary treatment, and are now basically being transformed. In addition, due to the shortage of water resources, many urban sewage treatment plants have considered sewage reuse, that is, some newly-built sewage treatment plants have set up advanced treatment, and this trend is gradually strengthening.
What are the levels of sewage treatment? Sewage treatment can be divided into primary, secondary and tertiary treatment.
Primary treatment mainly removes suspended solid pollutants from sewage, and most physical treatment methods can only meet the requirements of primary treatment. After primary treatment, BOD can generally be removed by about 30%, which can not meet the discharge standard. Primary treatment belongs to the pretreatment of secondary treatment.
The secondary treatment mainly removes colloid and dissolved organic pollutants (BOD, COD) in sewage, and the removal rate can reach over 90%, so that the organic pollutants can meet the discharge standards.
Tertiary treatment, further treatment of refractory organic matter, soluble inorganic matter such as nitrogen and phosphorus that can lead to eutrophication of water body. The main methods are biological nitrogen and phosphorus removal, coagulation and sedimentation, sand filtration and activated carbon adsorption.
Where can I get the sewage treatment grade certificate in Nanjing? You have to consult the Nanjing Municipal Public Bureau. Only they are qualified to issue it. The address is No.7 Maying, Dongzhi, Nanjing, and the telephone number is 523-379- 12. It's near the Chaotian Palace. Bus No.4, No.41,No.43, No.48, No.82, No.83 and No.306 can get off at Chaotian Palace.
Whether the welding grade of sewage treatment plant pipeline can be faked depends on technology.
What are the levels of sewage treatment? Generally divided into level 1, level 2 and level 3.
Advanced treatment, also known as pretreatment biochemical treatment
Pretreatment includes grid, sedimentation and sand removal.
Biochemistry is treated by biological methods such as AAO SBR oxidation ditch.
Advanced treatment may be coagulation, sedimentation, filtration, etc.
Share a design calculation book of Carrousel oxidation ditch to let you know more.
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What's the difference between a senior water treatment engineer and a sewage treatment worker? The operation certificate of sewage treatment worker is issued by the Ministry of Environmental Protection, and the grade certificate of sewage treatment worker is issued by Ministry of Human Resources and Social Security. I have never seen either of these certificates. Although I have worked in the environmental protection system for more than six years.
I feel that the certificate of the processor is a professional title certificate, and the identity is the professional title level of the workers and institutions. Similarly, there are assistant engineers, engineers, deputy senior engineers, senior engineers or assistant political engineers, political engineers, deputy senior political engineers and senior political engineers.