Bio-Minerals Combined with Bacillus cereus for Enhancing the Nitrogen Removal Efficiency under Aerobic Conditions

Nitrogen compounds such as nitrate, nitrite, and ammonium are among the prolonged contaminants in surface water and groundwater worldwide. In this study, we evaluated nitrogen removal efficiency using the combination of biologically synthesized Pd-FeS and Bacillus cereus in comparison between two batch reactors, one with a single nitrate (NO3--N) and the other with a mixed nitrogen (NO3--N + NO2--N + NH4+-N) under aerobic conditions. The removal efficiency of NO3--N by bio-Pd-FeS + Bacillus cereus in a single nitrate reactor showed 100% with a low production (ca. 10%) of NO2--N and NH4+-N for 5 days and this combination was three-fold more effective than a single application of bio-Pd-FeS and Bacillus cereus respectively. Also, bio-Pd-FeS + Bacillus cereus in the mixed nitrogen (NO3--N + NO2--N + NH4+-N) removed 95% NO3--N, 20% NO2--N, and 35% NH4+-N, respectively. Since iron and sulfur-based bio-minerals could be reusable in a reducing condition of in-situ and in an oxygen-limited closed condition of ex-situ applications, the results suggested that the combination should get more attention for an efficient eco-friendly sustainable bioremediation technology.