Abstract

Paracoccus denitrificans DL-23, isolated from aerobic domesticated activated sludge, was demonstrated to have high ability of denitrification and heterotrophic nitrification under aerobic condition. After optimization (succinate, COD/N 10, 37°C, 160 rpm), DL-23 removed 420 and 860 mg/l NO₃^- -N within 36 to 60 h of growth, respectively. DL-23 also removed 380 mg/l NH₄⁺-N within 24 h with ammonia as nitrogen source. The maximum removal rate was 30.3 mg/l·h. Meanwhile, DL-23 exhibited aerobic nitrite reduction ability with 658 mg/l NO₂^--N within 48 h.

Key words: Aerobic denitrification, heterotrophic nitrification, nitrogen removal,Paracoccus denitrificans.