The treatment of industrial wastewater can be divided into physical, chemical and biological methods:
1. Physical treatment is the cheapest treatment method using mechanical equipment and simple structure. General treatment methods include precipitation filtration, heat exchange, evaporation drying and combustion. Chemical treatment method is to add chemicals to the waste water to produce chemical reactions with polluting components, generate harmless substances or rubber plumes, and remove them, such as adding acid and alkali agents to adjust the pH value, adding chlorine, adding ozone, coagulation and precipitation, and ion replacement. Law, etc. The biological treatment method is a common method for treating sewage and organic industrial wastewater, and the microorganisms in the water can be decomposed into simple compounds without pollution. Effective wastewater treatment often requires multiple treatment units to be properly combined. Treatment of industrial wastewater
(1) Domestic sewage treatment The methods currently used for domestic sewage treatment can be divided into primary treatment, secondary treatment and tertiary treatment according to the degree of treatment. The primary treatment is physical precipitation or floatation to remove or crush the larger solids in the sewage, so that most of the sedimentable or suspended solids in the sewage are removed. If the chemical dosing is used for precipitation, the gelatinous substance can also be removed. . The secondary treatment is that the sewage is discharged after the primary treatment of the sink, and then the activated sludge aeration tank and the final sedimentation tank or other aerobic biological treatment and the final sink tank are discharged. The three-stage treatment method generally includes ion exchange method, break point addition filtration method to remove ammonia nitrogen, biological treatment denitrification method, reverse osmosis method, activated carbon adsorption, and the like.
(2) Septic tank treatment The septic tank treatment is the main method for the pre-treatment of urinary wastewater by Chinese people. The septic tank is mainly composed of a decay tank, a filter tank and a three-dimensional or flat oxidation tank. Sedimentation and anaerobic effect, feces and urine enter the tank through flushing, solid matter precipitates or rises and is decomposed by anaerobic bacteria or aerobic bacteria, and the sewage after filtering through the tank flows into the oxidation tank through the water dispersion device. Aerobic microorganisms decompose organic matter in sewage.
2. Treatment of domestic sewage Generally, households use flush toilets in the legal area, and the urine flows into the septic tank for treatment. However, the septic tank has a simple structure and a low treatment effect. Generally, the removal rate of BOD5 is less than 50%, which is not effective. Therefore, to solve the pollution problem of domestic sewage, the only way is to prevent it from being discharged into the water body and build a sanitary sewer system. The sewage is collected in a sewage treatment plant for treatment to reach the discharge standard and then discharged, so that it no longer pollutes the water body and completely solves the problem of urban environmental sanitation.