The influencing factors and the characteristics of simultaneous nitrification-denitrification in SBR

To investigate the mechanism of simultaneous nitrification and denitrification (SND) and promote the efficiency of SND system, by using the domesticated efficient SND sludge, the effects of organism, DO and temperature on the SBR reactor were studied. The experiment results showed that, when the temperature was 25-30 and pH was 7-9, the nitrate-nitrogen removal was preferably; when C/N rate varied between 1:1-8:1, COD concentration, ammonia nitrogen removal rate and TN removal rate decrease with the increasing of C/N rate. Dosing organic compounds in twice can enhance the aerobic denitrification effect. When aeration volume varied from 0.12 to 0.80 L·min^-1, ammonia nitrogen removal rate increased first and then kept approximate constant with the increase of aeration volume, finally became stable at 99.8%. TN removal rate increased first to the highest at 95.52%, then decreased, when aeration volume was 0.2 L·min^-1, and COD was stable above 91%. The influence of aeration rate on the COD removal is not distinct. The best effect will be achieved if the system temperature is 25-30°C, C/N rate is 1.5:1, aeration volume is 0.2 L·min^-1, pH is 7-9 and the dosing of organic compounds is in twice.