Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel-like layer

Eskandar Poorasgari, Poul Larsen, Xing Zheng, Per Halkjær Nielsen, Kristian Keiding, Morten Lykkegaard Christensen

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Abstract

Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBR)s, are generally divided into bound and free EPS. The free EPS are able to form a gel-like layer on the membrane active surface. The mechanisms involved in formation of such layer and its effects on performance of the MBR membranes were studied. The free EPS, extracted by centrifugation and microfiltration, contained a significant amount of humic-like substances. Under static contact to the membrane, adsorption of humic-like substances to the membrane occurred and could be explained by conventional adsorption kinetics. Due to static adsorption, surface roughness of the membrane declined significantly indicating that adsorbed matters to the membrane filled the cavities of the membrane surface. Filtration of the free EPS caused 50% water flux decline. The fouling resistance linearly increased with the amount of the humic-like substances retained during filtration as predicted by gel growth theory. A low pressure backwash could re-establish the water flux only up to 70%.
Original languageEnglish
Title of host publicationIrreversible fouling of membrane bioreactors due to formation of a non-biofilm gel-like layer
Number of pages10
Publication date2013
Publication statusPublished - 2013
EventIWA specialized membrane technology coference - Toronto, Canada
Duration: 25 Aug 201329 Aug 2013

Conference

ConferenceIWA specialized membrane technology coference
CountryCanada
CityToronto
Period25/08/201329/08/2013

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Keywords

  • free EPS, humic-like substances, adsorption, gel formation, fouling resistance,

Cite this

Poorasgari, E., Larsen, P., Zheng, X., Nielsen, P. H., Keiding, K., & Christensen, M. L. (2013). Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel-like layer. In Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel-like layer