Dye production wastewater contains acids, alkalis, salts, halogens, hydrocarbons, amines, nitrates, dyes  and intermediates, and some contain pyridine, cyanogens, phenols, benzidine and heavy metals such as mercury, cadmium, chromium, etc. The components of these wastewater are complex, toxic and difficult to treat. Therefore, the appropriate treatment method should be selected according to the characteristics of wastewater and the discharge requirements. For example: for the removal of solid impurities and inorganic substances, coagulation and filtration methods can be used; for the removal of organic and toxic substances, chemical oxidation, biological and reverse osmosis methods are mainly used; for the decolorization, coagulation and adsorption processes can be generally used; for the removal of heavy metals, ion exchange methods can be used