Abstract:
In order to investigate the intermittent aeration mode for achieving stable operation of the partral nitrification in farm manure slurry, an experiment was conducted using sludge from the aerobic zone of a sewage treatment plant as inoculated sludge and actual pig manure slurry as influent. The partral nitrification experiment was carried out in an upstream micro-aeration reactor by adjusting the intermittent aeration time. The results indicate that an aeration rate of 1.3 L/min, with 1 minute of aeration followed by 3 minutes of non-aeration, was more suitable for partral nitrification. The effluent NH
4+-N concentration was 87.9 mg/L, and NO
2−-N accumulation reaches was 103.3 mg/L. The removal rate of NH
4+-N and accumulation rate of NO
2−-N were found to be 57.4% and 87.3%, respectively. The ratio between effluent NH
4+-N and NO
2−-N was determined to have been 1:1.18, thus meeting the influent requirements for anaerobic ammonia oxidation. The analysis of community structure reveals that ammonia-oxidizing bacteria (
Nitrosomonas) were enriched, with its relative abundance increasing from 0.44% to 4.32%, while nitrite-oxidizing bacteria (
Nitrospira) were significantly inhibited, with their relative abundance decreasing from 6.76% to 0.16%.In conclusion, through controlling the intermittent mode with an aeration rate of 1 min per every three minutes at a flow rate of 1.3 L/min, stable partral nitrification in farm manure slurry was achieved, resulting in effluent that meets the influent requirements for anaerobic ammonia oxidation.