Enhancement of COD, ammonia, phosphate and sulfide simultaneous removal by the anaerobic photosynthetic bacterium of Ectothiorhodospira magna in batch and sequencing batch culture

Abstract

AbstractAn anaerobic photosynthetic bacterium, with chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total phosphorus (TP) and sulfide (S2−) simultaneous removal ability, strain SU6, was isolated and identified as belonging to Ectothiorhodospira magna. Its removal efficiencies were simultaneously evaluated in batch culture and influenced in sequencing batch culture. The maximum COD, NH3-N, TP and S2− removal rates of 93.04%, 86.70%, 37.55% and 99.99% were obtained in batch culture with an initial pH 8.0 at 35 °C after 72 h. The simultaneous removal efficiency was enhanced in sequencing batch culture, and 789.27 mg/L COD, 68.91 mg/L NH3-N, 70.20 mg/L S2− and 5.26 mg/L TP were removed by the end of the last cycle within 24 h. This was the first time of reporting contaminants' simultaneous removal by a pure-cultured photosynthetic bacterium. The experimental results demonstrate that E. magna can efficiently serve as a good candidate in anaerobic wastewater contaminants' simultaneous removal, and maybe as another model anaerobic photosynthetic microorganism for water purification investigations.