改良型A2／O-MBR工艺的反硝化除磷性能研究

重点考察了-种改良型膜生物反应器（A2／O—MBR）的脱氮除磷性能。该工艺主要特点在于对膜池硝化回流液进行了固液分离，并将上清液和浓缩污泥分别回流至缺氧池和厌氧池，这种改进提高了系统对氮、磷的同步去除效率。实验结果表明，在水力停留时间（HRT）为12h，污泥龄（SRT）为30d，混合液回流比为200％的运行条件下，进水COD、NH4＋-N、TN和TP平均浓度分别为（225±38）、（24．8±3．9）、（26．7±2．9）和（2．90±0．53）mg／L时，增加膜池硝化回流液固液分离装置前后，系统对COD和NH4＋-N的去除都维持在较高水平，而系统对TN和TP的去除效果显著提高，出水TN和TP平均浓度分别由（14．9±3．3）mg／L和（1．95±0．72）mg／L下降到（9．4±1．9）mg／L和（0．91±0．38）mg／L，表明增加膜池硝化回流液固液分离装置显著改善了A2／O-MBR系统的脱氮除磷效果。反硝化除磷活性实验结果进一步表明，改进后系统中反硝化除磷活性占总除磷活性的比例由51．5％上升至61．7％，说明增加膜池硝化回流液固液分离装置强化了系统的反硝化除磷性能。

Performance of denitrifying phosphorus removal in modified A2/O-MBR process

A modified anaerobic-anoxic-aerobic-membrane bioreactor（A2/O-MBR）was used to investigate its nitrogen and phosphorus removal performance. The main features of the process include separation of reflux liquid from the membrane reactor, as well as the recirculation of supernatant and concentrated sludge into anoxic tank and anaerobic tank, respectively, which improve the nitrogen and phosphorus removal efficiency simultane- ously. The experiment was conducted at HRT of 12 hours, SRT of 30 days and recirculation ratio of 200%. The results showed that when the average influent concentrations of COD, NH4＋ -N, TN and TP were （225 ± 38） mg/ L, （24.8±3.9） mg/L, （26.7 ± 2.9 ） mg/L and （2.90 ± 0.53 ） mg/L, respectively, no significant difference of the effluent COD and NH4 -N concentration was found between the systems with and without solid-liquid separator. However, the effluent TN and TP concentration were brought down from （ 14. 9±3.3） mg/L and （ 1.95 ± 0. 72） mg/L to （9.4 ±1.9） mg/L and （0. 91 ±0. 38） mg/L, respectively, when the system was equipped with solid-liq- uid separator. The results indicated that the nitrogen and phosphorus removal of the MBR system was significantly enhanced by addition of solid-liquid separator on nitrification reflux pipe. In addition, the denitrifying phosphorus removal activity assay showed that the ratio of denitrifying phosphorus removal activity to total phosphorus removal activity increased from 51.5% to 61.7% after addition of solid-liquid separator for nitrification reflux liquid, which indicated that the denitrifying phosphorus removal performance was strengthened by the modification.