Crossflow microfiltration using ceramic membrane for treatment of sulphur black effluent from garment processing industry

Crossflow microfiltration (CMF) using ceramic membrane, developed from a low cost composition of α-alumina and clay in the tubular multichannel configuration with filtration area of 0.045 m2 was used alone, and in combination with different physicochemical techniques, viz. adsorption and chemical coagulation for treatment of wastewater collected from the sulphur dyeing process of a garment processing industry. The concentrated effluent was enriched with sulphur black dye, with turbidity 5912 NTU and COD of 3910 mg/l. Adsorptive treatment was carried out using a biosorbent prepared from the roots of an aquatic weed, E. Crassipes. Chemical pretreatment was carried out using different inorganic coagulants. Effect of different transmembrane pressures (TMP) in the range of 0.4–1.2 kg/cm2 was observed and constant pressure filtration was conducted at 1 kg/cm2 TMP. Performance of the single stage CMF process was compared with that of two-stage processes in terms of the permeate quality, viz. COD, color, turbidity and TSS etc. and permeate flux. Encouraging result was found after microfiltration of the biosorbent treated feed as well as, effluent pretreated with aluminium sulphate. Dye removal was about 99%, with 80% reduction of COD. The chemical pretreatment process considerably increased the permeate flux compared to the single stage process.