Fouling of low-pressure membranes during drinking water treatment: effect of NOM components and biofiltration pretreatment

• Published in: Water science & technology. Water supply Vol. 14; no. 3; pp. 453 - 460
• Main Authors: RAHMAN, I, NDIONGUE, S, JIN, X, VAN DYKE, M. I, ANDERSON, W. B, HUCK, P. M
• Format: Journal Article
• Language: English
• Published: London International Water Association 01.06.2014; IWA Publishing
• Subjects: Addition polymerization; Anthracite; Applied sciences; Biofilters; Biofiltration; Biopolymers; Buildings. Public works; Detection; Drinking water; Exact sciences and technology; Fluid filters; Fouling; Liquid chromatography; Membrane processes; Membranes; Organic carbon; Pressure; Pretreatment; Raw water; Removal; River water; Rivers; Treated water; Ultrafiltration; Water quality; Water supply. Pipings. Water treatment; Water treatment; Performance evaluation; Drinking water treatment; Fouling; Experimental study; ultrafiltration membranes; Analysis method; Ultrafiltration; Biopolymer; Water quality; Membrane; Pretreatment; biopolymers; drinking water; Biofilter; biofiltration
• ISSN: 1606-9749; 1607-0798
• DOI: 10.2166/ws.2013.221

Fouling is a major challenge for low-pressure membrane drinking water treatment systems. Previous research has demonstrated that under the right conditions, biofiltration is an effective method to reduce fouling of low-pressure polymeric membranes. This study provides additional insight into the effect of biofiltration as a pretreatment for fouling reduction by using river water with different raw water quality characteristics than has been examined in previous studies. Two parallel pilot-scale dual media (sand/anthracite) biological filters were operated continuously over a period of 14 months. Liquid chromatography–organic carbon detection analysis confirmed that the parallel biofilters performed similarly with both averaging on 21% biopolymer removal. Raw and treated water biopolymer concentrations were correlated, with increased absolute removals occurring at higher raw water concentrations. Ultrafiltration (UF) membrane fouling experiments showed substantial improvement in performance following biofiltration pretreatment by reducing hydraulically irreversible and reversible fouling rates by 14–68% and 8–55%, respectively. The results also reaffirm the importance of biopolymers at concentrations as low as ∼0.1 mg/L on irreversible and reversible UF membrane fouling and a minimal impact of humic substances.