title: Iron deficiency and bioavailability in anaerobic batch and submerged membrane bioreactors (SAMBR) during organic shock loads.
abstract: This study examined the effects of Fe(2+) and its bioavailability for controlling VFAs during organic shock loads in batch reactors and a submerged anaerobic membrane bioreactor (SAMBR). When seed grown under Fe-sufficient conditions (7.95±0.05mgFe/g-TSS), an organic shock resulted in leaching of Fe from the residual to organically bound and soluble forms. Under Fe-deficient seed conditions (0.1±0.002mgFe/gTSS), Fe(2+) supplementation (3.34mgFe(2+)/g-TSS) with acetate resulted in a 2.1-3.9 fold increase in the rate of methane production, while with propionate it increased by 1.2-1.5 fold compared to non-Fe(2+) supplemented reactors. Precipitation of Fe(2+) as sulphides and organically bound Fe were bioavailable to methanogens for acetate assimilation. The results confirmed that the transitory/long term limitations of Fe play a significant role in controlling the degradation of VFAs during organic shock loads due to their varying physical/chemical states, and bioavailability.
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, Singapore 637141, Singapore. Electronic address: BKetheesan@ntu.edu.sg.
authors.forename: Balachandran
authors.initials: B
authors.lastname: Ketheesan
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, Singapore 637141, Singapore. Electronic address: PHAM0073@e.ntu.edu.sg.
authors.forename: Pham Minh
authors.initials: PM
authors.lastname: Thanh
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, Singapore 637141, Singapore; Department of Chemical Engineering, Imperial College London, London SW7 2BY, UK. Electronic address: d.stuckey@ic.ac.uk.
authors.forename: David C
authors.initials: DC
authors.lastname: Stuckey
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D001682:Biological Availability; D019149:Bioreactors; D005232:Fatty Acids, Volatile / Q000378:metabolism; D000090463:Iron Deficiencies; D009930:Organic Chemicals / Q000737:chemistry / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods*; D062065:Wastewater / Q000737:chemistry
chemical_list: D056804:Biofuels; D005232:Fatty Acids, Volatile; D009930:Organic Chemicals; D062065:Wastewater
keywords: Anaerobic digestion; Fe(2+) supplementation; Metal bioavailability and speciation; Organic shock loading; Submerged anaerobic membrane bioreactor