Application of nanofiltration as a tertiary treatment in a polyester production industry for wastewater reuse

Abstract

Membrane technology is one of the most efficient approaches for the treatment of industrial wastewater and reuse. In this study, the influence of influential parameters, including pH, feed pressure, sulfate concentration, and chemical oxygen demand (COD) on the simultaneous removal efficiency of pollutants in Polyacryl Iran Company, were investigated by applying a commercial TFC polyamide nanofilter. The three leveled factors of sulfate and COD concentration, feed pressure, and pH were considered in the range of 550–1,283 mg L−1, 85–198 mg L−1, 0.5–0.9 MPa, and 5–9, respectively. By increasing pH from 5 to 9, the sulfate and COD removal efficiency increased up to 90%, and also by increasing feed pressure from 0.5 to 0.8 MPa, the removal rate of COD increased to 92%, whereas the effect of feed pressure on the sulfate removal was found insignificant. Results also indicated that an increase in the COD concentration resulted in a reduction in the removal efficiency of COD from 96 to 82%. On the other hand, by increasing the sulfate concentration to 800 mg L−1, an increase in the sulfate removal efficiency from 94 to 96% was observed. A further increase in the sulfate concentration resulted in the reduction of sulfate removal efficiency. © 2015 Balaban Desalination Publications. All rights reserved.