Bio-enhanced contact oxidation process using a heterotrophic nitrifying-aerobic denitrifying strain

Abstract

The intention of this study was to explore whether it is feasible to use a heterotrophic nitrifying-aerobic denitrifying strain to bio-enhance the biological contact oxidation process. In this experiment, Acinetobacter sp. RW, a highly efficient heterotrophic nitrifying-aerobic denitrifying strain isolated in the laboratory, was used as the functional strain. The results show that part of the NH4 +-N (ammonia nitrogen), TN (total nitrogen) and CODCr (dichromate oxidizability) of the sewage could be effectively removed via the biological contact oxidation process performed in the laboratory. Average removal ratios of NH4 +-N, TN and CODCr increased by 32.8%, 4.33% and 11.13%, respectively, after biological enhancement of RW. According to the biodiversity information, Acinetobacter exhibited the greatest change at the genus level in both the water and biofilm after adding the strain RW. In the 12 days without RW addition, the treatment efficiency of the device was only 1.01% different from that during daily dosing. The results demonstrate that the treatment efficiency of the process can be improved by adding RW. RW can effectively adhere to the biofilm and become one of the dominant strains. Therefore, we conclude that the biological contact oxidation process bio-enhanced by RW was successful and has practical potential.