Microbial removal of vanadium (V) from groundwater by sawdust used as a sole carbon source

Bioremediation of vanadium (V) (V(V)) for polluted groundwater is an emerging topic globally. With this study, microbial removal of V(V) was investigated by sawdust of pine used as a sole carbon source. The removal efficiency of V(V) reached up to 90.3% with anaerobic sludge as inocula and sawdust as the carbon source in nutrient solution. Microbial removal of V(V) could be enhanced by adding medical stone and phosphate rock, from 53.2% up to 82.6% in real groundwater. Microbiological analysis revealed such microbes as Thauera accumulated, which could contribute to V(V) reduction. Such functional species as Bacteroidetes vadinHA17 norank and Anaerolineaceae norank helped degradation of sawdust. In column experiments with domesticated sludge or indigenous microbes from soils, microbial V(V) removal efficiencies (on 26 d) with sawdust were around 58.7% (BS), 54.8% (BP) and 38.4% (BU), respectively. The study can offer a potential approach to microbially removing V(V) for contaminated groundwater and even for disposal of agricultural and forestry wastes. [Display omitted] •V(V) is effectively reduced by microbes using sawdust as solid carbon sources.•Medical stone and phosphate rock enhance V(V) bioremediation in actual groundwater.•Accumulation of microbes such as Thauera could contribute to V(V) reduction.•Sawdust supports effective V(V) removal in column bioreactors with various inocula.