CAST工艺常规模式下脱氮性能研究

Study on nitrogen removal performance in conventional mode of CAST process

研究了有效容积为21.6 L的循环式活性污泥法反应器在常规模式下,处理模拟废水时,有机污染物和氮污染物的去除情况,并分析了反应器脱氮过程中的限制性因素。结果表明,在反应器的运行周期为4 h(进水曝气2 h,沉淀和排水各1 h)好氧区DO>2 mg/L,污泥浓度MLSS稳定在4 000 mg/L时,污泥回流比为20%,COD和氨氮的去除率可达90%。对一个典型周期进行监测分析,氨氮去除彻底,出水主要是硝态氮,总氮去除率约为69%。静态试验测得氨氮氧化速率为8.0 mg NH4+-N/(g MLSS.h),硝态氮生成速率为3.3 mg NO3--N/(g MLSS.h)。从实验结果可以分析出,在上面运行条件下CAST工艺脱氮限制性因素是回流比和污泥龄。

The removal performance of organic matter and nitrogen pollutants in conventional mode of CAST reactor with effective volume of 21.6 L feeded with simulation wastewater was studied.The limiting factors of nitrogen removal in the process were analyzed.When the reactor operated 4 h in one period,DO2 mg/L,MLSS was about 4 000 mg/L,the result showed that COD and ammonia removal could get 90%.It can be found that ammonia nitrogen was removed completely in aerobic zone and nitrate accumulation occurred in a typical cycle.Total nitrogen removal rate was about 69%.Static test showed that the ammonia oxidation rate was 8.0 mg NH＋4-N/（g MLSS·h） and the nitrate generation rate was 3.33 mg NO-3-N/（g MLSS·h） in the CAST reactor.Under the above process operating conditions,CAST nitrogen limiting factors were the sludge recycle ratio and SRT.