Waste water treatment in the chemical industry
Secondary treatment is mainly to remove biodegradable organic solutes and some colloidal substances, reduce the biochemical oxygen demand and part of the COD in the wastewater, usually using biological treatment. After biological treatment of wastewater, but also a considerable amount of residual COD, sometimes with high color, smell, taste, or because of high environmental health standards, it is necessary to use tertiary treatment methods for further purification. Tertiary treatment is mainly to remove organic pollutants and dissolved inorganic pollutants in wastewater that are difficult to biodegrade. Commonly used methods include activated carbon adsorption and ozone oxidation, and ion exchange and membrane separation technology can also be used. Various chemical industrial wastewater can be based on different water quality, water quality and discharge water quality requirements after treatment, the choice of different treatment methods.