Simultaneous Removal of High-Strength Ammonium and Phosphorus by Alcaligenes faecalis No. 4

Alcaligenes faecalis No. 4 (No. 4), which conducts heterotrophic nitrification and aerobic denitrification, removed 800 mg-N/l of highstrength ammonium and 100 mg-P/l of phosphorus, both in a synthetic medium and in an anaerobically digested municipal sludge solution. The estimated N2 conversion ratio from ammonium-nitrogen was approximately 50%. When the initial phosphorus concentration was reduced to approximately 30 mg-P/l in the synthetic medium, the phosphorus limited the growth of No. 4 after 8 h when more than 90% of P had been consumed, and then stopped the growth of No. 4 after that. The N2 conversion ratio from ammonium-nitrogen was nearly100%.