Study On The Wastewater Treatment Process Of Azo Pigment

Azo pigment, which is the most complete spectrum, most widely applied and lower costdye, is widely applied in textile industry, printing and dyeing, leather industry etc. At present,the treatment of azo dye waste water is still a very difficult problem in our country. So thestudy on the treatment process is very important and useful.The Gangu pigment factory industrialwastewater is this experiment’s study odject, thatbelongs to the high concentration, difficulty to degrade and organic wastwater. In theproduction process produces two kinds of wastwater; one kind is the mother lipuor wastwater,mainly produces in the pigment production chemical reaction process,floats the washingwater by the reaction and the initial period primarily; another kind of wastwater to rinse thepigment and the flushing equipment,flushes ground.This pigment industrial wastwater havethe following several obvious characteristics:(1) the high CODcr density, this industrywastewater belongs to the models highly concentrated organic industrial wastewater. Thepartial mother liquor’s CODcr value reaches as high as above10000mg/L.(2) poorbiodegradability,a very low value of B/C.(3) the water quality change is big,rinse water wasmixed when it was dealing with partical production waste water, and similar different brandsof the waste water discharge pigment concertration, the actual pollutant concertration willproduce change.(4) the production is a single product, azo pigment wastewater with highnitrogen content, can cause C:N:P microbal basic source of nurition imbalance especially thephosphorus salt. Based on the above several characteristics, the economical and effectiveprocessing pigment wastewater is the question mainly needs to solve.Through to studying the pigment wastewater disposal method,as well as combining theexisting research results and through a series of experiment,the treatment process wasadopted, what is coagulation sedimentation+A2/O biochemical treatment. After a seriestreatments, select polymeric ferric sulfate to pretreat the wastewater, then through thecomparison of different dosage on the removal rate of CODcr and chroma in the wastewaterdetermine the amount of coagulant dosage is1g/L. The effects of biochemical treatment bydifferent retention time of wastwaer shows that the HRT of the aerobic pool is3h, the HRT ofthe anoxic pond is2h, the HRT of the aerobic pool is4h, combining the analysis of thenitrogen removal effect on wastewater, determine the reflux ratio of200%, to achieve stableoperation can achieve the stable operation.The test results show that,it is effectively use the coagulation sedimentation process+A2/O biochemical treatment to dispose Gangu paint factory production wastewater. Theresults indicated that the removing ratio of CODcr may reach80%, the removing ratio ofchromaticity may reach99%. And the quality achieve the first-class standard of National Discharge Standards. The research indicated that the wastwater treatment processes has highfeasibility and good treatment effect.What provides experimental theory basis for the projectpractice and the scientific research.