Influence of aeration rate on shortcut nitrification in an SBR treating anaerobic-digested piggery wastewater

Abstract

AbstractThe aeration rate as an intrinsic factor influencing shortcut nitrification process while treating ammonium-rich anaerobic-digested piggery wastewater (ADPW) in a sequencing batch reactor (SBR) was investigated. Diluted ADPW with nitrogen loading rate (NLR) of 0.56 ± 0.12 kg/(m3 d) was fed to start up the SBR at 0.1 L/min aeration rate. After 24 d of operation, the shortcut nitrification process was established, 71.1% ammonium was removed and a nitrite accumulation rate (NAR) of 96.8% was obtained. Ammonium removal decreased remarkably to 48.6% as raw undiluted ADPW with an NLR of 2.55 kg/(m3 d) was fed to the system. Intriguingly, aeration rate was raised to 0.4 L/min in the latter feed and an enhanced ammonium removal of 68.9% was observed while NAR decreased to 94.4%.