Complete bromate and nitrate reduction using hydrogen as the sole electron donor in a rotating biofilm-electrode reactor

Abstract

Simultaneous reduction of bromate and nitrate was investigated using a rotating biofilm-electrode reactor (RBER) with graphite carbon (GC) rods as anode and activated carbon fiber (ACF) bonded with steel ring as cathode. In RBER, the community of denitrifying bacteria immobilized on the cathode surface could completely utilize hydrogen (H2) as the electron donor, which was internally produced by the electrolysis of water. The short-term test confirmed that the RBER system could reduce 150-800μg/L bromate to below 10μg/L under autotrophic conditions. The reduced bromate was considered to be roughly equivalent to the amount of bromide in effluent, indicating that bromate was completely reduced to bromide without accumulation of by-products. The long-term test (over 120 days) showed that the removal fluxes of bromate and nitrate could be improved by increasing the electric current and decreasing the hydraulic retention time (HRT). But nitrite in effluent was significantly accumulated when the electric current was beyond 10mA and the HRT was less than 6h. The maximum bromate reduction rate estimated by the Monod equation was 109.12μg/Lh when the electric current was 10mA and HRT was 12h. It was proposed that the electron transfer process in RBER produced H2 on the surface of the ACF cathode, and the microbial cultures attached closely on the cathode which could completely utilize H2 as electron donors for reduction of bromate and nitrate.

Bromate and Nitrate Bioreduction Coupled with Poly-β-hydroxybutyrate Production in a Methane-Based Membrane Biofilm Reactor

“…NO 3 – could have multiple effects on BrO 3 – reduction. NO 3 – might promote BrO 3 – reduction, since nitrate reductases in bacteria are reported to reduce BrO 3 – . , NO 3 – may act as the primary electron acceptor to support the accumulation of bacteria also able to respire BrO 3 – . , NO 3 – might also slow BrO 3 – reduction due to the competition for a scarce electron donor. , Downing et al showed that NO 3 – was reduced prior to BrO 3 – in a hydrogen (H 2 )-based MBfR when H 2 was limiting…”

“…− reduction due to the competition for a scarce electron donor. 28,29 − in a hydrogen (H 2 )-based MBfR when H 2 was limiting. 30 The first objective of this study was to document BrO 3 − reduction using CH 4 as the sole electron donor and carbon source.…”

Microbial community with the ability to biodegradation perchlorate in a bio-electrochemical reactor

“…The results of the two samples were summed up for the analysis of microbial diversity. The total DNA was extracted using the E.Z.N.A.® Soil DNA Kit (Omega Bio-tek, Norcross, USA) [19]. 16S rRNA genes were amplified using the universal bacteria forward primer 338F (5'-ACTCCTACGGGAGGCAGCAG-3') and reverse primer 806R (5'-GGACTACHVGGGTWTCTAAT-3'), which were targeting the V3-V6 hypervariable regions.…”

Effects of Electrical Stimulation on the Degradation of Azo Dye in Three-Dimensional Biofilm Electrode Reactors

“…Biofilm electrode reactors (BERs) have been studied by various researchers as an effective means of removing pollutants in wastewater treatment processes [1][2][3][4]. In such applications, water electrolysis produces hydrogen gas (H 2 ), which can be utilized by microorganisms on the surface of the cathode as an electron donor [5].…”