title: Pretreatment with alum or powdered activated carbon reduces bacterial predation-associated irreversible fouling of membranes.
abstract: This study evaluated the co-application of bacterial predation by Bdellovibrio bacteriovorus and either alum coagulation or powdered activated carbon adsorption to reduce fouling caused by Escherichia coli rich feed solutions in dead-end microfiltration tests. The flux increased when the samples were predated upon or treated with 100 ppm alum or PAC, but co-treatment with alum and predation gave the best flux results. The total membrane resistance caused by the predated sample was reduced six-fold when treated with 100 ppm PAC, from 11.8 to 1.98 × 10(11) m(-1), while irreversible fouling (Rp) was 2.7-fold lower. Treatment with 100 ppm alum reduced the total resistance 14.9-fold (11.8 to 0.79 × 10(11) m(-1)) while the Rp decreased 4.25-fold. SEM imaging confirmed this, with less obvious fouling of the membrane after the combined process. This study illustrates that the combination of bacterial predation and the subsequent removal of debris using coagulation or adsorption mitigates membrane biofouling and improves membrane performance.
authors.affiliation: a School of Urban and Environmental Engineering , Ulsan National Institute of Science and Technology , Ulsan , South Korea.
authors.forename: Eun-Ho
authors.initials: EH
authors.lastname: Kim
authors.forename: Mohammed
authors.initials: M
authors.lastname: Dwidar
authors.forename: Young-Nam
authors.initials: YN
authors.lastname: Kwon
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Mitchell
mesh_terms: D000327:Adsorption; D000534:Alum Compounds / Q000737:chemistry*; D001501:Bdellovibrio / Q000502:physiology*; D057219:Biofouling / Q000517:prevention & control*; D002606:Charcoal / Q000737:chemistry*; D004926:Escherichia coli / Q000502:physiology; D008567:Membranes, Artificial; D008962:Models, Theoretical; D014462:Ultrafiltration / Q000379:methods; D018508:Water Purification / Q000379:methods
chemical_list: D000534:Alum Compounds; D008567:Membranes, Artificial; D002606:Charcoal; C041524:aluminum sulfate
keywords: Bdellovibrio bacteriovorus; alum; irreversible fouling; membrane filtration; powdered activated carbon