Research On The Condition And Influnce Factors Of Shortcut Nitrification-denitrification In A~2/O~2 Process

In recent years, with the rapid development of industry and the improvement of people's living,the discharge of nitrogenouseffluent is increasing,especially the wastewater which is produced by nitric fertilizer industry is amount with low C/N,so it's hard to satisfy the carbon source demand of traditional process for nitrogen removal. Shortcut nitrification-denitrification and anaerobic ammonium oxidation process are suit to treat wastewater with less carbon,in order to accelerate the engineering application of shortcut nitrification-denitrification,the A2/O2 process(anoxic-anaerobic-microaerobic-aerobic) was used to treat the nitric fertilizer wastewater in the simulation test device and finally we can drew the following conclusions:(1) High nitrite accumulation rate was achieved in microaerobic pool while the operating conditions were controlled as follows:the temperature of microaerobic pool was 24～28℃, pH was 7.5～8.0, DO was 1.0 mg/L and reduced to 0.5 mg/L after 30 days, the DO of aerobic pool was 3.0 mg/L, the sludge age was 15d, the nitrosation liquid reflux ratio was 150% and the nitrification fluid was 200% while the sludge reflux ratio was 80%. During the stable experiment, it was found that stable nitrite accumulation can be achieved and the rate reached an average of 88% while the removal efficiency of ammonia nitrogen achieved 90%, TN 68% and COD 86.4%.(2)The variation of the nitrite accumulation rate and the removal rate of ammonia and total nitrogen were analysed with different DO, pH and temperature while the other conditions remained the same, it proved that the most suitable DO was 0.5-0.7mg/L; the pH was 7.5-8.0 and the temperature was 24-28℃.(3)In the intermittenttest device, the degradation of ammonia nitrogen was inspected, and it proved that the activity of nitrosobacteria in the hypoxic environment is poor, the removal efficiency of ammonia nitrogen can reach more than 95% if the HRT of the microaerobic pool was extended slightly.(4) The relation between the concentration of ammonia nitrogen and ORP was analysed and finally a formula was founded:ORP=-49.7121g[NH4+-N]+101.9.