Dye production wastewater contains acids, bases, salts, halogens, hydrocarbons, amines, nitros and dyes and their intermediates, and some also contain pyridine, cyanide, phenol, benzidine and heavy metals such as mercury, cadmium and chromium. These wastewater components are complex. It is toxic and difficult to handle. Therefore, the treatment of dye production wastewater. The appropriate backwash filter treatment method should be selected according to the characteristics of the wastewater and its discharge requirements.
For example, the removal of solid impurities and inorganic substances, coagulation method and filtration method can be used; the removal of organic matter and toxic substances mainly adopts chemical oxidation method, biological method and reverse osmosis method; decolorization can generally adopt a process composed of coagulation method and adsorption method. In the process, the heavy metal can be removed by ion exchange or the like.
The harmless treatment of the backwashing filter can be divided into physical treatment methods such as precipitation method and adsorption method. The precipitation method mainly removes suspended matter in the wastewater; the adsorption method mainly removes dissolved pollutants and decolorization in the wastewater. The chemical treatment methods include a neutralization method, a coagulation method, and an oxidation method. The neutralization method is to adjust the pH in the wastewater, and also to reduce the color of the wastewater; the coagulation method is to remove the disperse dyes and colloidal substances in the wastewater; the oxidation method is to oxidize the reducing substances in the wastewater to precipitate the sulfur dyes and the vat dyes.www.inocofiltration.com