Autotrophic induced heterotrophic bioreduction of bromate in use of elemental sulfur or zerovalent iron as electron donor

Abstract

Bioreduction of bromate using elementary sulfur (S(0)) or zerovalent iron (Fe(0)) as electron donor was studied. After 60-day cultivation, the microbial consortium achieved high bromate conversion of 91.9 ± 2.1% and 90.0 ± 4.0% in the S(0) and Fe(0) amended tests. A coupling mechanism involving autotrophic oxidation of S(0) or Fe(0) to convert bicarbonate to volatile fatty acids followed by bromate reduction at the oxidation of the volatile fatty acids to CO2 was proposed to interpret the noted reactor performances. The key functional strains including S(0) or Fe(0) oxidizing bacteria (Thiomonas and Ferrovibrio) and bromate reducing bacteria (Pseudoxanthomonas and Clostridium sp.) are identified. The studied system can provide an efficient BrO3− conversion way with no external organic carbon sources.