Abstract: The phosphorus removal by the biological nutrient removal system depends on the exclusion of excess sludge，which requires short SRT micro-organisms；while the nitrifying bacteria is autotrophic，its growth requires a longer time. At low temperature (≤10℃)，the nitrification sludge age is generally 15－20 d，and PAOs sludge age is 4－5d，this enormous gap resulted in the difficult to achieve simultaneously nitrogen and phosphorus removal at low temperature with the A²/O process. Thus，the effect of nitrogen and phosphorus removal using improved inverted A²/O process is studied，through which the COD removal rate of higher than 85%，NH₄⁺-N removal of 85% and T-P removal efficiency of 80 % were achieved at low temperature conditions. With this improved inverted A²/O process，the effluent can reach the national emission standards for secondary water.

摘要：

生物脱氮除磷系统中磷的去除通过排放剩余污泥实现，需要短泥龄微生物；而硝化细菌为自养菌，需要较长的生长时间。在低温（≤10℃）条件下，硝化污泥泥龄一般为15～20 d，而聚磷菌泥龄为4～5 d，这种巨大的泥龄差距导致现有A2/O在低温下很难实现同时脱氮除磷。本文利用改良的倒置A2/O工艺，研究了低温条件下的生物脱氮除磷效果。结果显示：该工艺低温条件下COD的去除率在85％以上，氨氮去除率低温条件下可达到85%，磷的去除率低温条件下为80%，出水能够达到国家二级排放标准。