Ultra- and Nano-Filtration in Advanced Effluent Treatment Schemes for Pollution Control in the Pulp and Paper Industry

Abstract

The kraft pulp and paper industry is currently faced with the challenge of substantially reducing the discharge of conventional and toxic pollutants to the receiving environment without compromising its competitiveness. Ultrafiltration (UF) and nanofiltration (NF) are among the various unit processes that are being investigated by researchers interested in developing alternative schemes for meeting this challenge. The objectives of the work presented here were: (i) to review the potential uses for UF and NF in the kraft pulp and paper industry and (ii) to evaluate the performance of eleven UF and NF membranes using a caustic extraction stage effluent from a kraft mill pulping softwood with a O D55/C45 EO H D bleaching sequence. The experimental work was conducted with two flat-sheets bench-scale units fed in parallel: a low shear and a high shear unit. The most promising UF membrane gave an average permeate flux of 9 m3m2d for a volume reduction factor (VRF) of 30, under high-shear conditions at 0.69 MPa. The associated COD rejections ranged from 85%–90% at a VRF of 1 down to 70–75% at a VRF of 30. While the results demonstrated in this study show promise, further research is needed to demonstrate the cost effectiveness of both high-shear and low-shear equipment for this application as well as options for the reuse or treatment of the diluted and concentrated streams produced by the UF/NF systems.

Wastewater Treatment and Reclamation: A Review of Pulp and Paper Industry Practices and Opportunities

“…One of the key considerations is to employ a membrane having sufficiently fine pore distribution to exclude the passage of biological cells and viruses. The following studies have employed ultrafiltration to separate clarified water from the solids in P&P mill process waters or effluent (Minami et al 1991;Zaidi et al 1992;Ragona and Hall 1998;Huuhilo et al 2002;Tavares et al 2002;Komesvarakul et al 2003;Nuortila-Jokinen et al 2004;Mänttäri et al 2008; Ordonez et al 2010;Puro et al 2010;Gönder et al 2011Gönder et al , 2012Simonič and Vnučec 2012;Singh et al 2012;Quezada et al 2014). Notably, Tavares et al (2002) were able to demonstrate the removal of metals from such effluent.…”

Treatment of combined bleaching effluent by membrane filtration technology for system closure in paper industry

“…Even if only 50% of the total solids are kept in the concentrate, 90% of the color is retained. Zaidi et al [8], Afonso and Pinho [9], Falth [10], compared the efficiency of (i) ultrafiltration and (ii) ultrafiltration plus dissolved air flotation for bleach plant effluent. The results showed 54%, 88%, 100% removal of TOC, color, and SS, respectively by ultrafiltration alone.…”

Pulp and paper effluent management

“…The compactness of the Biofor" process makes it especially attractive where space is limited. Zaidi et al (1992) conducted lab-scale experiments to review the potential uses for ultrafiltration (UF) and nanofiltration (NF) in the kraft pulp and paper industry and to evaluate the performance of II UF and NF membranes using a caustic extraction stage effiuent from a softwood bleached kraft mill. Three commercial nanofiltration membranes (Afonso et aI., 1992) were used for the removal of chlorinated organic compounds from the first alkaline extraction effiuent originated from a kraft mill, using eucalyptus wood as raw material.…”