Influence of Low Air Pressure on the Partial Denitrification-Anammox (PD/A) Process

Low air pressure is a feature of high-altitude regions. Domestic wastewater from such regions typically has low carbon-to-nitrogen ratio (C/N ratio). These factors combine to make traditional biological nitrogen removal in inefficient and more energy-intensive. The partial denitrification-anaerobic ammonium oxidation (PD/A) process was reported remove ammonia municipal sewage, consuming fewer carbon sources requiring no aeration supply. In this study, we set up laboratory-scale reactors simulated environmental conditions, studied the effect on PD/A process. We found that promotes efficiency (NRE), achieving 93.0 ± 0.3% at 65 kPa, contribution rate anaerobic (anammox) increased 77.7%. Lower dissolved oxygen (DO) concentrations caused by lower were reason for higher nitrite accumulation (NAE) denitrification (PD) system, with measured values 78.4 2.8% kPa. anammox promoted pressure, mainly because resulted ammonia-oxidizing bacteria activity, specific activity (SAA) reaching 26.3 mg·N/(g·VSS·d). Although relative abundance partial-denitrifying declined slightly, kPa compared 96 they still dominant genus sludge, continued generate steadily, even pressures. bacterial remained relatively stable, but their increased, which aided This study demonstrates how process, indicating possibility sustainable improved