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

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