Variations of Nitrogen Metabolization Process Under Typical Loading Phases in Full Scale Leachate Anoxic/Aerobic System Via Enzyme Activity and Microbial Community

Abstract

Evolution of nitrogen metabolism enzyme activity and microbial community were identified, and obvious distinction were found in typical scenarios of nitrification failure in high loading phases (HL) and low C/N ratio in low loading phases (LL) based on a working leachate treatment process, which 15±5% higher ammonia removal efficiencies were achieved in LL. Hydroxylamine oxidoreductase was found to be the key enzyme and sensitive factor in nitrogen metabolism, since the corresponding activity decreased by 90%, as the influent TN increased from 2450 mg/L to 3100 mg/L in HL. Denitrifying enzyme activity abated by 1.3% as the C/N ratio dropped by 1% in LL. The relative abundance of norank_f_Saprospiraceae decreased from 33.66% to 11.94%, and then almost disappeared in low C/N ratio, with the total influent COD loading decreased from 22,000 mg/L to 12,000 mg/L, which could be responds for the excessive COD loading as the critical indicator.

Keywords: Nitrogen metabolism, Enzyme active, Microbial community, Full scale leachate working plant, Sensitive factor