The Study Of Printing And Dyeing Wastewater Treatment Using The Complex Of Coagulants And Clay Mineral

The wastewater produced in the printing & dyeing industry is the main pollution source of textile industry.If the wastewater weren't treated before being discharged, this would affect the ground water seriously.Thus may destroy the ecology balance of water and make water septic.The composition of dyeing effluent is considerable complex.It contains many kinds of organic dyestuff.It has complex characteristic, such as strong toxicity,deep colour,the wide fluctuations,difficult biodegradable,the wide variation of composition with a large quantity of water.So the dyeing wastewater is quite difficult for wastewater treatment.Understanding and developing suitable technology for dyeing effluent treatment is the important task of environmental protection industry.At present the research on dyeing effluent treatment is quite active,the main decolorization methods include adsorption,coagulation,redox,ion exchange,reverse osmosis,biochemistry and so on.However,there is little reserch on the method of using complex of flocculants and clay mineral to deal with the dyeing effluent,and there is even less reserch on the mechanism of this method.In this paper,the study is keen on dealing with the simulated dyeing effluent with the complex of coagulants and attapulgite.The effect of decolorization were studied by using the complex of cagulants and attapulgite to treat simulated disperse,acid and reactive dyeing effluent,as well as the synergistic effect compared the composite with their separate coagulant.The pH value of the effluent,the quantity of coagulants, activation temperature of clay,the ratio of coagulant to clay and other factors affecting color and COD removal rate and their mechanism were also discussed to define the best parameters.Finally,we studied the applicability of the complex method to the other two dyeing effluent by using the complex of cagulant and attapulgite to treat simulated disperse and acid dyeing effluent.The experimental results indicated that a synergistic effect was obtained for the decolorization of the simulated reactive,disperse and acid dyeing effluent by using coagulant Poly Ferric-Aluminous-Sulphate(PFAS) or Aluminum Sulfate(AS)and attapulgite simultaneously under the suitable condition.The decolorization of the simulated disperse and acid dyeing effluent can reach the value of 95%.The decolorization and COD reduction of the simulated reactive dyeing effluent can reach the values of 90%and 75%respectively.The method of using the complex of coagulant(PFAS or AS) and attapulgite have a better color and COD removal rate and wider application range of the pH value of the effluent than using coagulant only.The method of using the complex of coagulant(PFAS or AS) and attapulgite to treat reactive dyeing effluent from printing & dyeing mill has a very high application value.On the one hand,it improves the color and COD removal rate at the situation that the color and COD removal rate of the reactive dyeing effluent is so high.Also it can avoid the pH adjusting for dyeing effluent and has a good settling property performance and faster filtering rate.The clay also has several traits,such as fewness secondary pollution problem,low cost and can be recycled.Thus,this complex method has a good application prospect in the treatment of dyeing wastewater and should be promoted.