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

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

doi:10.2166/wst.2014.068

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

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

Research output: Contribution to journal › Journal article › Research › peer-review

6 Citations (Scopus)

Abstract

Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBRs), are generally divided into bound and free EPS. The free EPS are able to form a gel 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 membranefilled the
cavities of the membrane surface. Filtration of the free EPS caused 50% waterflux 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 language	English
Journal	Water Science and Technology
Volume	69
Issue number	8
Pages (from-to)	1641-1647
Number of pages	7
ISSN	0273-1223
DOIs	https://doi.org/10.2166/wst.2014.068
Publication status	Published - 23 Apr 2014

Keywords

adsorption, cake resistance, free EPS, gel formation, humic-like substances,

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10.2166/wst.2014.068

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title = "Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel layer",

abstract = "Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBRs), are generally divided into bound and free EPS. The free EPS are able to form a gel 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 centrifugationand 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 membranefilled thecavities of the membrane surface. Filtration of the free EPS caused 50% waterflux 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%.",

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doi = "10.2166/wst.2014.068",

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T1 - Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel layer

AU - Poorasgari, Eskandar

AU - Larsen, Poul

AU - Zheng, Xing

AU - Nielsen, Per Halkjær

AU - Keiding, Kristian

AU - Christensen, Morten Lykkegaard

PY - 2014/4/23

Y1 - 2014/4/23

N2 - Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBRs), are generally divided into bound and free EPS. The free EPS are able to form a gel 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 centrifugationand 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 membranefilled thecavities of the membrane surface. Filtration of the free EPS caused 50% waterflux 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%.

AB - Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBRs), are generally divided into bound and free EPS. The free EPS are able to form a gel 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 centrifugationand 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 membranefilled thecavities of the membrane surface. Filtration of the free EPS caused 50% waterflux 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%.

KW - adsorption, cake resistance, free EPS, gel formation, humic-like substances,

U2 - 10.2166/wst.2014.068

DO - 10.2166/wst.2014.068

M3 - Journal article

SN - 0273-1223

VL - 69

SP - 1641

EP - 1647

JO - Water Science and Technology

JF - Water Science and Technology

IS - 8

ER -

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

Abstract

Keywords

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