| Printing and dyeing wastewater has the characteristics of high content of organic matter,deep color,large quantity of water and complicated water quality.It is a kind of industrial wastewater which is difficult to be degraded,based on the foundation of previous studies and the findings of my own research,this paper chooses the combination process of enhanced coagulation-hydrolytic acidification-MBBR to treat printing and dyeing wastewater,and studies and analyzes each process,the effect of influencing factors on the removal efficiency of printing and dyeing wastewater,the optimum operating parameters and the mechanism were investigated.Activated and carbonized sludge was used to prepare activated sludge biochar as coagulation intensifier,and the removal effect of common coagulation and enhanced coagulation on different printing and dyeing wastewater and the factors affecting the removal effect were studied.The results showed that the enhanced coagulation could remove the dye molecules with strong hydrophilicity,high solubility,complex structure and High Association degree,the removal rates of COD and colority were 30% and36% respectively,and the removal rates of COD and colority were increased by 14%and 26%,when the initial p H value is 8 ～ 10,the removal rate can be kept high,and the higher the dosage of sludge biological carbon is,the better the removal effect is,with the increase of porosity,the adsorption performance was enhanced,and the precipitation after enhanced coagulation was analyzed by FTIR,which showed that a new functional group appeared in the coagulation precipitate,it shows that pollutants in printing and dyeing wastewater are removed by enhanced coagulation and adsorption.MBBR was suspended in a closed-aeration process,and hydrolyzed and ACIDIFIED/MBBR was acclimated.When the removal rate of COD and chroma reached 80%,the acclimated process was finished and the reactor started.It is found that hydrolytic acidification can improve the biodegradability of printing and dyeing wastewater through preliminary study on the effect of Operation Parameters on the removal of pollutants,the removal efficiency of COD and Chroma can reach more than80% when combined with hydrolytic acidification/MBBR When the optimum HRT of hydrolytic acidification and MBBR were 12 h and 8 h respectively,the DO of MBBR was kept at 4 mg/L,and the initial p H of influent was neutral or weakly alkaline,the removal effect of dyeing wastewater was better and more economical.It was found that most of the hydrolytic acidification was bacterial microorganism,and there were a lot of protozoa and Metazoa in MBBR.There were many kinds of biofacies and they grew well in MBBR.The combined process was operated continuously and steadily for 30 days under the conditions of PAC and sludge bio-carbon dosage of 200 mg/L and 300 mg/L respectively,initial p H of 8 ～ 10,hydrolytic acidification and mhrt of 8 and 12 H respectively,initial p H of 7 ～ 9,DO of 4 mg/L,the removal rates of COD,Chroma and ammonia-nitrogen were kept at a high level,above 90%,90% and 98%,respectively,the peaks of influent at 664 nm,292 nm and 246 nm decreased continuously,and even disappeared at the effluent stage,and the effluent at 218 nm produced new peaks,the final degradation to a simple structure of the small molecular substances,pollutants were removed.Figure [28] Table [6] Reference [73]... |
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