title: Separation of competitive microorganisms using anaerobic membrane bioreactors as pretreatment to microbial electrochemical cells.
abstract: Anaerobic membrane bioreactors (AnMBRs) as pretreatment to microbial electrochemical cells (MECs) were first assessed for improving energy recovery. A dual-chamber MEC was operated at hydraulic retention time (HRT) ranging from 1 to 8d, while operating conditions for an AnMBR were fixed. Current density was increased from 7.5 ± 0 to 14 ± 1A/m(2) membrane with increasing HRT. MEC tests with AnMBR permeate (mainly propionate and acetate) and propionate medium confirmed that propionate was fermented to acetate and hydrogen gas, and anode-respiring bacteria (ARB) utilized these fermentation products as substrate. Membrane separation in the AnMBR excluded fermenters and methanogens from the MEC, and thus no methane production was found in the MEC. The lack of fermenters, however, slowed down propionate fermentation rate, which limited current density in the MEC. To symphonize fermenters, H2-consumers, and ARB in biofilm anode is essential for improving current density, and COD removal.
authors.affiliation: Civil & Environmental Engineering Department, University of Waterloo, ON N2L 3G1, Canada.
authors.forename: Bipro Ranjan
authors.initials: BR
authors.lastname: Dhar
authors.forename: Yaohuan
authors.initials: Y
authors.lastname: Gao
authors.forename: Hyeongu
authors.initials: H
authors.lastname: Yeo
authors.forename: Hyung-Sool
authors.initials: HS
authors.lastname: Lee
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000302:isolation & purification*; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D004560:Electricity; D055664:Electrochemical Techniques; D005232:Fatty Acids, Volatile / Q000032:analysis; D008567:Membranes, Artificial; D011422:Propionates / Q000378:metabolism; D013997:Time Factors; D014865:Waste Disposal, Fluid
chemical_list: D005232:Fatty Acids, Volatile; D008567:Membranes, Artificial; D011422:Propionates; C029658:propionic acid
keywords: Anaerobic membrane bioreactor (AnMBR); Anode-respiring bacteria (ARB); Energy recovery; Microbial electrochemical cells (MECs)