In order to efficiently utilize carbon source of low C/N ratio domestic sewage

two methods (reducing organics input and increasing carbon source consumption through denitrification) were introduced through the partial nitritation SBR. In this study

five factors

i.e. influent volume

drainage ratio

aeration time

precipitation time and stirring time after aeration were investigated to assess the effect on the utilization efficiency of carbon source(the ratio between the quality of carbon source consumption through denitrification and the total organics input). The results showed that when the drainage ratio was decreased from 50% to 35%

the utilization efficiency improved from 15.1% to 24.8%; when the aeration time was increased from 2 h to 2.25 h

the utilization efficiency increased from 24.8% to 27.5% and when 1.5 h of stirring time after aeration was added

the utilization efficiency increased by 3.8%. Meanwhile

the nitrite accumulation rate of the effluent was 94.8% and the NO2--N/NH4+-N was 1.7

indicating that the partial nitrification was stably maintained

and the effluent was more proper for simultaneous anammox and denitrification (SAD) process. All in all

the organics utilization efficiency was promoted gradually through the adjustment of the operational parameters above

by which the aeration energy for consuming organics was saved

and then the multiplication of aerobic heterotrophic bacteria was weakened which avoided striking the ammonia oxidizing bacteria (AOB) effectively

keeping the nitritation effect stable.