中文摘要：

山东省某污水处理厂设计规模为20×10^4m^3／d，生化处理采用双沟交替式氧化沟工艺。由于设备老化以及运行管理等问题，导致双沟交替式氧化沟无法实现缺氧、好氧交替运行。通过增加导流墙、硝化液回流等措施，将双沟交替式氧化沟改造为A2／O工艺，同时增加V型高效纤维滤池深度处理以及化学除磷工序。工艺升级改造后运行稳定，出水水质达到《城镇污水处理厂污染物排放标准》（GB18918--2002）的一级A标准。

英文摘要：

The design capacity of Jinan sewage treatment plant （the second sewage treatment plant） was 20 ×10^4m^3/d, and biological treatment process was DE-type oxidation ditch process. Because of high requirement for automatic control, equipment aging and management problem, the DE-type oxidation ditch cannot be operated under alternating anoxic/aerobic conditions. To support the East Route Project of South-to-North Water Diversion and to improve water quality of the Xiaoqing River, water quality improvement and reconstruction of nitrogen and phosphorus removal process were conducted. By adding the diversion wall, nitrification liquid reflux and other measures, the DE-type oxidation ditch process was transformed into A2/O process, while the V-type high-efficiency fiber filter and chemical phosphorus removal process were added. After the upgrade, the process was stable, and the effluent quality met the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （ GB 18918 - 2002）.