Due to the complex sources of raw materials, fuels, and auxiliaries, and the changeable components of printing and dyeing industrial wastewater, it is difficult to meet the discharge requirements only by biochemical methods. , the dosage of decolorizer will directly affect the degree of flocculation of colloidal particles, dye intermediate molecules and color-developing organic matter in printing and dyeing wastewater, effluent quality and wastewater treatment cost. Polyferric sulfate(PFS) has good electrical neutralization, adsorption bridging and net capture, and has a good removal effect on colloids, particulates and soluble substances in wastewater, and forms flocs with high density and fast precipitation, so the removal of CODcr higher rate.
Printing and dyeing wastewater has the characteristics of large amount of water, high content of organic pollutants (some CODcr values can reach more than 100,000 mg/L), high chroma, high alkalinity, large changes in water quality and pH value, etc. It is one of the difficult industrial wastewaters to treat. one. At present, the main methods for the treatment of printing and dyeing wastewater include physicochemical method, biochemical method, chemical method and a combination of several processes. Among them, the coagulation and sedimentation method can effectively remove the COD and chroma in the printing and dyeing wastewater. The purpose of coagulant for the treatment of printing and dyeing wastewater is to obtain a chemical with low cost and more convenient effect. The results show that the combination of polyferric sulfate and decolorizing agent can effectively achieve the expected purpose.