Conditioning the alternating aerobic–anoxic process to enhance the removal of inorganic nitrogen pollution from a municipal wastewater in France

Abstract

Inorganic nitrogen pollution from surface waters can adversely affect human health and the environment. Coupled nitrification–denitrification can significantly remove the total inorganic nitrogen pollution amount from municipal wastewater; however, researchers only have a limited understanding of the alternating aerobic–anoxic process in a single reactor. This study performed a typical treatment using a completely mixed alternating aerobic–anoxic extended aeration treatment process in a single reactor, biological fluidised bed reactor to remove inorganic nitrogen pollution from a municipal wastewater in France. Comparative analysis of the coupled nitrification–denitrification reactions was carried out to investigate the two different alternating aerobic–anoxic processes of 3-h aerobic digestion and 6-h anoxic time and 3-h aerobic digestion and 3-h anoxic time. The results indicate that the change in anoxic time, specifically, from 6 to 3 h, can increase the alternating aerobic–anoxic process performance by approximately 53.4%. The average effluent inorganic nitrogen concentration decreased from 10.3 to 4.8 mg N/L, achieving the desired inorganic nitrogen concentration of less than 10 mg N/L in the outflow to meet the stringent effluent standards. The study offers a proper treatment that can be used to help reduce inorganic nitrogen pollution from municipal wastewater processed in a single-sludge reactor. The study's results advance the understanding of this simple technique that effectively removes inorganic nitrogen pollution from municipal wastewater.