【摘要】 采用A/O-MBR工艺处理低C/N(3~5)生活污水,考查溶解氧(DO)、水力停留时间(HRT)及回流比(R)对脱氮效果的影响,并对处理过程进行全氮分析。结果表明,该工艺NH4+-N去除率在95%以上,但TN去除率最高仅为66%,TN去除在DO=2~3 mg/L、HRT=9 h及R=300%时分别出现峰值,缺氧段处理效果明显优于好氧段。对处理过程的全氮分析表明,28~32℃水温条件下,系统亚硝化率(NO2-/TN)保持在3%以下的低比率,说明短程硝化反硝化作用可以忽略,TN去除主要依赖硝化反硝化;控制DO=2~3 mg/L、HRT=9 h,系统好氧池硝化率(NO3-/TN)维持在61%~90%之间,缺氧池硝化率随R增加逐渐上升,在R=300%时达到高点76%;控制DO=2~3 mg/L、R=300%,缺氧池硝化率也在HRT=9 h时达到高点。结果表明,A/O-MBR工艺维持TN去除效果的先决条件是缺氧池达到足够的硝化率。由于反硝化细菌是典型的异养菌,TN去除不够理想主要源于进水碳源相对缺乏。除了增加碳源的传统措施外,提高TN去除率应更多地关注工艺条件的改进。更多还原

【Abstract】 A/O-MBR technique was adopted to deal with the low C/N(3~5) sewage. During the running time, the effects of dissolved oxygen(DO), hydraulic retention time(HRT) and reflux ratio(R) to denitrification were researched. Then nitrogen analysis of the processing was performed. The results indicated that the NH4+-N removal ratio of the system was above 95%,but the maximum removal of TN was just 66%. When DO=2~3 mg/L,HRT=9 h and R=300%, the peaks of the TN removal were occurred respectively. The treatment efficiency of anoxic zone was better than aerobic zone. The nitrogen analysis of the processing showed that the nitrosation ratio of the system remained a low rate of below 3%, which illustrated that the shortcut nitrification and denitrification could be ignored and the TN removal mainly depended on the nitrification and denitrification. In the charge of DO=2~3 mg/L,HRT=9 h, the nitrifying rate of aerobic pool remained between 61%~90%. The nitrification rate of anoxic increased gradually with the increase of R,when R=300%,it reached as high as 76%. In the charge of DO=2~3 mg/L,R=300%,the nitrification rate of anoxic pool reached a high point when HRT=9 h. The research indicated that the prerequisite of A/O-MBR system to maintain TN removal was that anoxic pool could achieve adequate anoxic nitrification rates under the process conditions. Since denitrifying bacteria is a typical kind of heterotrophic bacteria, the unsatisfactory TN removal of the system is mainly due to the relative lack of carbon source. In addition to the traditional measure which increases carbon source, more attention should be payed to improve the process conditions so that TN removal can be increased.更多还原