常温CSTR部分亚硝化影响因素及工况优化研究

Research on influencing factors and operation optimization for CSTR partial nitrification at normal temperature

为了更好地实现并维持稳定的部分亚硝化效果,以低氨氮人工配水为研究对象,采用连续流完全混合式活性污泥法(CSTR),在常温条件下对部分亚硝化工艺的影响因子和准佳工况进行了研究。结果表明,HRT=(3.0±0.2)h,DO为0.40～0.50 mg/L,回流比R=20%～30%时,平均氨氧化率为53%,且工艺出水NO2--N/NH4+-N平均为1.11∶1,适宜作为系统长期稳定运行的工况。若持续缩短HRT会导致反应器内污泥浓度降低,部分亚硝化效果受到影响。反应器在上述工况运行时,DO=0.50 mg/L是亚硝化率下降的临界浓度;系统进出水pH差值可良好表征出水亚硝酸盐氮与氨氮浓度的比例。

Abstract In order to achieve and maintain stable performance of partial nitrification, the influencing factors of partial nitrification and optimum conditions were studied using synthetic wastewater with low ammonia nitrogen concentration at normal temperature in a CSTR. Results showed that under the condition of HRT = （3.0± 0.2） h, DO = 0.40 - 0.50 mg/L, R = 20% -30% , the average ammonia nitrogen removal rate reached 53% , NO2- - N/NHf -N in the effluent of partial nitrification system reached 1.11：1 which was suitable for the long-term run of this system. Shortening the HRT continuously would make a great loss of sludge, then affect the performance of CSTR. DO = 0.50 mg/L was critical for nitrite accumulation under optimal conditions ; the different values of influent and effluent pH can well characterize the effluent ratio of NO2- -N/NH4＋ -N.