Piggery wastewater treatment using Alcaligenes faecalis strain No. 4 with heterotrophic nitrification and aerobic denitrification

Alcaligenes faecalis strain No. 4, which has heterotrophic nitrification and aerobic denitrification abilities, was used to treat actual piggery wastewater containing high-strength ammonium under aerobic conditions. In a continuous experiment using a solids-free wastewater (SFW) mixed with feces, almost all of the 2000 NH4+–N mg/L and 12,000 COD mg/L in the wastewater was removed and the ammonium removal rate was approximately 30 mg–N/L/h, which was 5–10 times higher than the rates achieved by other bacteria with the same abilities. The denitrification ratio was more than 65% of removed NH4+–N, indicating that strain No. 4 exhibited its heterotrophic nitrification and aerobic denitrification abilities in the piggery wastewater.