Chemical treatment of printing and dyeing wastewater

In many industrial production processes, a large number of organic matter containing aqueous solution will be produced. Whether it is for the purification of products or the discharge of production wastewater, it is necessary to remove the organic matter in the water. Industrial printing and dyeing wastewater treatment can efficiently and quickly extract organic matter from aqueous solution, and effectively separate organic matter from water. The basic principle of the equipment is to make the initial mixed oil and water phase enter the bottom of the separation tank through a tangential nozzle to form a three-phase swirling flow driven by the pressure air flow. In this process, the oil-water two-phase droplets collide with each other fiercely to complete the transfer of the extract between the two phases.

In recent years, the effect of ozone as oxidant is better. Ozone has strong oxidation ability, which can effectively destroy the chromogenic groups of some dyes and decolorize the wastewater. It can also oxidize and degrade some organic compounds which are difficult to biodegrade without increasing the amount of sludge.

Chemical treatment. There are neutralization method, coagulation method and oxidation method. The neutralization method is to adjust the pH value of wastewater and reduce the chroma of wastewater, so that some soluble dyes in waste water can be easily precipitated and precipitated, so as to improve the biological treatment effect. Coagulation is a method of flocculating sedimentation by adding coagulant to remove disperse dyes and colloidal substances, which can reduce chromaticity by 90% and remove cod50-70%. Oxidation process can be divided into aeration oxidation method and oxidant oxidation method. Aeration oxidation process is to direct the air into the waste water tank to oxidize the reducing substances in the wastewater, so as to precipitate sulfide dyes and reducing dyes. This method is not used alone, but as pretreatment of aerobic biological treatment and coagulation treatment. The oxidant oxidation process uses oxidants such as chlorine, hypochlorite, ozone and hydrogen peroxide to remove dyes in wastewater by oxidation, so as to reduce BOD and COD values in wastewater.