Study On The Treatment Technology Of Dye Wastewater

Dye wastewater is one of the most difficult to deal with industrial wastewaterwhich has complicated components, high chromacity and COD_Crvalue. According tostatistics,20ton clean water would be polluted by one dye wastewater. Though ourcountry is in the adjustment of industrial structure, gradually banning and eliminatinga number of smaller dyestuff production enterprise with serious pollution, but in someregions, a number of small dyestuff production enterprise with backward productivetechnology, discharge wastewater without effective processing into water body, whichreduce the transparency of body water and is harmful to the growth of hydrobiont andmicroorganism; meanwhile, would reduce the self-cleaning capacity of body waterand damage water, soil and the ecological environment seriously. Therefore, with theadjustment of industrial structure of our country, strengthening environmentalprotection and reducing pollution emission, has become the consensus of the wholesociety.At present, the dye wastewater treatment methods mainly consist of physicalmethod, chemical method, biological method and some combination technology andso on. Along with the increasingly difficult of dye wastewater treatment and theimproved requirements of environmental protection, the traditional processing methodis difficult to achieve the emission standards, and therefore, further research anddevelopment of high efficiency dye wastewater treatment technology is needed. Inrecent years, the electrochemical and photocatalytic oxidation method is studiedintensively. Electrocoagulation, Cu/Fe internal electrolysis and UV/Fentonphotocatalytic oxidation methods are applied in this paper to treat dyes wastewaterwith high concentration, the work and conclusions are included as follows: （1） By orthogonal experiment design, electrocoagulation is used to treat ReactiveYellow X-R, Weak Acid Red3R, Acid Chrome Black T, Direct Orange S foursimulation dye wastewater, the results showed that the decolourization of reactivedyes wastewater, direct dyes wastewater and acid dyes wastewater is better than weakacid dyes wastewaters. Through the treatment of simulation dye wastewater to makesure the optimization conditions of seven industrial dye wastewater is A₂B₃C₂D₂, thatis with a PH of7.5, a current of5A, a speed of3r·s^-1 and a cycle times of4. In theseconditions, the decolourization of pigment violet was90%, the diethylaniline andAniline Black was achieve80%, the KN-B and dye Mother Liquor was about75%,the pyrazolone and dye Manufacturing Shop effluent was more than50%, then to theCOD_Crremoval of the seven industrial dye wastewater was about35⁴5%.（2） The Fe/Cu internal electrolysis process was used to pro-treat the mixedindustrial dye wastewater. By choosing and optimizing the influence factors includepH, reaction time and m（Fe）/m（Cu）, make sure the optimization conditions of internalelectrolysis is a pH of3with a reaction time of30min, and m（Fe）/m（Cu） of30:1,now the removal percentages of color and COD_Crwere70%and54.1%, respectively.Compared electrocoagulation with internal electrolysis, the results showed that theyare both efficient to the dye wastewater. By contrast, internal electrolysis is better thanelectrocoagulation reconsidering the cost and effect in this experiment.（3） The UV/Fenton catalytic oxidation was used to treat the dye wastewater afterinternal electrolysis process, investigate the influence of dosages of FeSO₄·7H₂O andH₂O₂,pH value, the illumination intensity and illumination time respectively. Theresults show there is no need to adjust pH value and Fe²⁺for UV/Fenton catalyticoxidation process after internal electrolysis process, avail to simplified the reactionprocess and reduce the cost. The optimization conditions of UV/Fenton catalyticoxidation is30%H₂O₂of64mL/L with illumination intensity of33W, and a reactiontime of45min, then the accumulative removal of color and COD_Crwere found to be86.7%and87.7%respectively. Compared UV/Fenton catalytic oxidation with Fenton catalytic oxidation, the results showed that UV/Fenton catalytic oxidation is betterthan Fenton catalytic oxidation reconsidering the cost and effect in this experiment.