There are many types of industrial sewage, and they do not have a basically unified model like urban sewage.
Take printing and dyeing wastewater as an example:
Dye production wastewater contains acids, alkalis, salts, halogens, hydrocarbons, amines, nitro compounds, dyes and their intermediates and other substances, including It also contains pyridine, cyanide, phenol, benzidine and heavy metals such as mercury, cadmium and chromium. The composition of these wastewaters is complex. It is toxic and difficult to handle. Therefore, the treatment of dye production wastewater. It should be based on the characteristics of wastewater and its discharge requirements. Choose appropriate treatment methods. For example: to remove solid impurities and inorganic substances, coagulation and filtration can be used; to remove organic and toxic substances, chemical oxidation, biological methods, reverse osmosis, etc. are mainly used; decolorization can generally use a process consisting of coagulation and adsorption. Process, heavy metals can be removed by ion exchange method, etc.
Take food wastewater as an example:
The food industry has a wide range of raw materials and products, and the quantity and quality of wastewater discharged vary greatly. The main pollutants in wastewater are (1) solid substances floating in wastewater, such as vegetable leaves, peels, minced meat, poultry feathers, etc.; (2) substances suspended in wastewater include grease, protein, starch, colloidal substances, etc.; ( 3) Acids, alkalis, salts, sugars, etc. dissolved in wastewater: (4) Silt, sand and other organic matter entrained in raw materials; (5) Pathogenic bacteria and viruses, etc. Food industry wastewater is characterized by a high content of organic matter and suspended solids, is easily corruptible, and is generally not highly toxic. Its main hazards are eutrophication of water bodies, causing the death of aquatic animals and fish, causing organic matter deposited on the bottom of the water to produce odor, deteriorating water quality, and polluting the environment. In addition to appropriate pretreatment according to water quality characteristics, biological treatment is generally suitable for food industry wastewater treatment. If the requirements for effluent water quality are very high or the organic matter content in the wastewater is very high, a two-stage aeration tank or a two-stage biological filter, or a multi-stage biological turntable can be used. Or a combination of two biological treatment devices can be used, or an anaerobic-aerobic series biological treatment system can be used.