Study On The Treatment And Reuse Of Dyeing Wastewater By Integrated Membrane System

With the simplicity of operation, effective treatment and stable water production, membranetechnology has been the hotspot for the advanced treatment and reuse of dyeing wastewater inrecent years. In this paper, an UF–NF integrated membrane system (IMS) has been selected andinvestigated as the method of advanced treatment and reuse of the practical dyeing wastewater.In this work, study on nanofiltration treatment for the simulation system of the practicalwastewater was carried out. Both the dye and salts rejections of nanofiltration membrane for thesimulation system of the wastewater could both achieve above98%. Factors such as operationpressure, temperature that influence the membrane performance have been optimized, which hascertain significance for the practical wastewater treatment by the integrated membrane system.An UF–NF integrated membrane system has been selected and investigated as the method ofadvanced treatment and reuse of the practical printing and dyeing wastewater. The results showedthat, pretreatment with the hollow-fiber ultrafiltration membrane module could obtain better effect,印染废水with part removal of the chromaticity and about30%removal of COD. Also, withnanofiltration treatment after the pretreatment, the COD was less than25mg/L and the saltsrejection was above90%in the permeate, which could not only achieve the grade one emissionsstandard level, but also meet the dyeing industry water reuse standard. In addition, there was littledifference of the treatment effect between the ESPA1low pressure reverse osmosis membrane andthe widely used DL nanofiltration membrane. However, the flux of the DL membrane was higherthan that of the ESPA1membrane. Therefore, with low energy consumption and cost, thenanofiltration membrane was a better choice than the reverse osmosis membrane for thewastewater treatment.The membrane resistance of both the ESPA1low reverse osmosis membrane and the DLnanofiltration membrane was analyzed. It was found that the membrane resistance of the ESPA1membrane was larger than that of the DL membrane, which proved that nanofiltration membranehad advantages in term of the energy saving. Finally, both the polluted ultrafiltration membraneand nanofiltration membrane were cleaned by hydraulic and chemical cleaning respectively. Theresults indicated that chemical cleaning was more effective for both of the membranes. Withchemical cleaning, the flux of the polluted ultrafiltration and nanofiltration could recover to93%and97%of the initial flux respectively.