title: Effects of ferric iron on the anaerobic treatment and microbial biodiversity in a coupled microbial electrolysis cell (MEC)--anaerobic reactor.
abstract: Adding Fe(III) into a MEC - anaerobic reactor enhanced the degradation of organic matters. To clarify the respective effects of combining Fe(III) dosage and a MEC and Fe(III) dosage only on strengthening anaerobic digestion, three anaerobic reactors were operated in parallel: a MEC - anaerobic reactor with dosing Fe(OH)3 (R1), an anaerobic reactor with dosing Fe(OH)3 (R2) and a common anaerobic reactor (R3). With increasing influent COD from 1500 to 4000 mg/L, the COD removal in R1 was maintained at 88.3% under a voltage of 0.8 V, which was higher than that in reactor R2 and R3. When the power was cut off, the COD removal in R1 decreased by 5.9%. The addition of Fe(OH)3 enhanced both anaerobic digestion and anodic oxidation, resulting in the effective mineralization of volatile fatty acids (VFAs). The reduced Fe(II) combined with electric field resulted more extracellular polymeric substances (EPS) production. Quantitative real - time PCR showed a higher abundance of bacteria in the anodic biofilm and R1. Pyrosequencing and denaturing gradient gel electrophoresis (DGGE) analysis revealed that the dominant bacteria and archaea communities were richer and more abundant in the anode biofilm and R1.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors.forename: Jingxin
authors.initials: J
authors.lastname: Zhang
authors.forename: Yaobin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xie
authors.initials: X
authors.lastname: Quan
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
mesh_terms: D000693:Anaerobiosis; D044822:Biodiversity; D018441:Biofilms / Q000187:drug effects; D019149:Bioreactors / Q000382:microbiology*; D004572:Electrolysis / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005290:Ferric Compounds / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D005232:Fatty Acids, Volatile; D005290:Ferric Compounds
keywords: Anaerobic; Fe(III); Microbial electrolysis cell; Pyrosequencing