Effect of sludge loading on kinetics and nitrite accumulation capacity of denitrification process
To enhance the treatment capacity of partial denitrification coupled with Anammox(PD/Anam-mox)process,the impact of loading on nitrogen conversion pathway during denitrification process was investigat-ed.Batch experiments were conducted to explore the effects of different sludge loadings on kinetics and nitrite accumulation capacity during denitrification.Additionally,by altering the sludge loadings in long-term continu-ous experiments,the influence of it on partial denitrification process was verified.In batch experiments,higher loadings resulted in lower reaction rates of NO2--N and NO3--N and higher NO2--N accumulation capacity,with the nitrite accumulation rate(NAR)reaching a maximum of 72.47%.Under lower sludge loading,the reactions were accelerated,the NO2--N reduction rate was increased and the NAR was reduced to 56.46%.In continuous experiments,increasing the sludge loading by shortening HRT improved the reactor's partial denitrification ca-pacity,rose the NAR from 26.86%to 45.62%,the sludge activity was increased,and in the denitrification activi-ty test,the NAR reached 90.24%.The sludge exhibited a more granular structure,with increased particle size and extracellular polymeric substance content.The results of the short-term batch and long-term continuous ex-periments showed that,increasing sludge loading is an effective strategy to enhance the partial denitrification ca-pacity during the denitrification process.