title: Influence of substrate on fouling in anoxic immersed membrane bioreactors.
abstract: The influence of carbon substrate chemistry on membrane bioreactor (MBR) fouling in anoxic conditions has been evaluated. The use of a weak carboxylic acid (acetic acid) resulted in the production of large open-floc structures (up to 508microm) that were susceptible to breakage. Primary particles (d(10) and d(20) particle sizes, 5.5+/-1.3 and 15.3+/-8.2microm, respectively) and macromolecular soluble microbial products (SMPs) were generated, directly impacting on membrane fouling. The use of a primary alcohol (ethanol), on the other hand, encouraged the growth of flocs similar to activated sludge. These flocs produced low concentrations of primary particles (d(10) and d(20) particle sizes, 120.6+/-36.1 and 185.2+/-62.7microm, respectively) and high-molecular-weight SMP, and the particles had sufficient mechanical integrity to withstand shear. Consequently, the use of ethanol resulted in sufficient suppression of fouling to extend the filtration time by a factor of three. An increase in MLSS concentration did not directly impact upon fouling when operating with ethanol, primarily because of the low concentration of particulate matter produced.
authors.affiliation: Centre for Water Science, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK. e.j.mcadam.2003@cranfield.ac.uk
authors.forename: Ewan J
authors.initials: EJ
authors.lastname: McAdam
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Judd
authors.forename: Elise
authors.initials: E
authors.lastname: Cartmell
authors.forename: Bruce
authors.initials: B
authors.lastname: Jefferson
mesh_terms: D000693:Anaerobiosis; D018533:Biomass; D001704:Biopolymers / Q000302:isolation & purification; D019149:Bioreactors; D002244:Carbon; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D005453:Fluorescence; D008567:Membranes, Artificial; D008970:Molecular Weight; D010316:Particle Size; D011312:Pressure; D012995:Solubility; D014462:Ultrafiltration / Q000379:methods*
chemical_list: D001704:Biopolymers; D008567:Membranes, Artificial; D002244:Carbon