Nanofiltration for recovering wastewater from a specific dyeing facility

Textile processing industry generally requires significant amount of process water for cleaning, rinsing and dyeing purposes. Advanced membrane separation with high efficiency, ease and economic of operation as one of the most promising technologies has become increasingly attractive for reclamation of wastewater due to the shortage of fresh water supplies caused by the development of global population and industry. The objective of the study was to investigate the feasibility for recovering the wastewater from a specific dyeing facility by nanofiltration (NF). Process review at the dyeing facility was conducted and wastewater streams were characterized. A bench scale unit with total membrane area of 465 cm2 was used in this study. Trials were conducted to recover the wastewater using three types of NF membranes. The results indicated that the NF membrane process performed high efficiency of >99% for dye removal and NE-70 membrane showed better performance in terms of flux and separation than Desal-5 membrane. Turbidity, hardness, TOC and color of the treated water were less than 0.2 NTU, 60 mg/L as CaCO3, 10 mg/L and 5 HU, respectively. It could be concluded that it was feasible to recover 70% of the wastewater from the dyeing facility using a NF membrane process and the quality of the treated water could meet the requirements of dyeing process.