Improving microbial bioremediation efficiency of intensive aquacultural wastewater based on bacterial pollutant metabolism kinetics analysis

Abstract

How to effectively bioremediate aquacultural wastewater using microbes is an urgent issue for the application of aquaculture beneficial microorganisms. Purple non-sulfur bacteria (PNSB) are beneficial in preventing related pollution in aquaculture applications. An autochthonous PNSB Rhodobacter sphaeroides was employed in this study to explore an effective bioremediation strategy of aquacultural wastewater. The test bacterium showed high performance in the removal of ammonium (97.50% ± 0.78% of 42 mg L−1 NH4+-N) and phosphate (93.24% ± 0.71% of 50 mg L−1 PO43--P) in the synthetic wastewater, which are the two crucial indicators of the aquacultural wastewater bioremediation. The study also unveiled that the imbalanced ratio of nutrients in water was the principal reason for limiting the efficient bioremediation of shrimp-culture wastewater. Therefore, an effective microbial bioremediation strategy was proposed by comprehensively considering bacterial pollutant metabolism kinetics constants such as specific consumption yields of chemical oxygen demand (COD)/phosphorous and nitrogen/phosphorous. Finally, COD, total nitrogen (TN), total phosphorus (TP), and ammonium (NH4+-N) in the wastewater were examined, and the results showed that they all decreased to the acceptable values. In conclusion, this study suggested a novel method for improved bioremediation efficiency of aquacultural wastewater, and the findings revealed that this strategy is promising due to its characteristics to be used in various aquaculture wastewater types.