Abstract:

In order to study the feasible solution for further upgrading the effluent quality of three groups （six channels） surface exposure DE oxidation ditch of Xi'an Beishiqiao Sewage Treatment Plant，based on the minimum change of the existing civil structure，and on the premise of changing the surface exposure to bottom exposure，two renovation ideas were put forward. One idea maintained the existing double⁃ditch alternating operating，the other changed three groups of ditches into two groups，triple⁃ditch alternating operating. On this basis，an experimental model was made to simulate the change of DE oxidation ditch from surface exposure to bottom exposure，and the pilot experiment of alternating operation of double⁃ditch and triple⁃ditch was carried out. It was found that after changing to bottom exposure，the system could run stably under double⁃ditch and triple⁃ditch alternating mode，and the effluent indicators under the same conditions were less than that before transformation. After installing MBBR packing，the ammonia nitrogen and COD in the effluent of the biological sedimentation tank of the two operation modes after the overall transformation could stably meet the quality requirements of class Ⅳ effluent of the Environmental Quality Standard for Surface Water（GB 3838—2002）（ammonia nitrogen≤1.5 mg/L and COD≤30 mg/L），while total nitrogen could reach less than 12 mg/L and total phosphorus could reach less than 1 mg/L. The oxidation ditch with double⁃ditch or triple⁃ditch alternating operation both could be used as an alternative process for DE oxidation ditch upgrading.

Key words: DE oxidation ditch, alternate operation of double?ditch and triple?ditch, bottom exposure

摘要：

为研究西安市北石桥污水厂的3组（6道）表曝DE氧化沟出水水质进一步提标改造的可行方案，以现有构筑物土建结构改动最小为出发点，表曝改底曝为前提，引申出维持现有双沟交替运行，以及将3组沟改为2组、三沟交替运行2种改造思路。在此基础上制作实验模型，模拟将表曝DE氧化沟改为底曝，并对改底曝后的氧化沟分别进行双沟和三沟交替运行的小试实验。研究发现，改为底曝后，双沟、三沟交替模式下系统均能稳定运行，同等条件下出水各项指标均小于改造前。之后再加装MBBR填料，整体改造后的2种运行模式生物沉淀池出水中的氨氮和COD均能稳定满足《地表水环境质量标准》（GB 3838—2002）Ⅳ类出水水质要求（即氨氮≤1.5 mg/L，COD≤30 mg/L），总氮能达到12 mg/L以下，总磷能达到1 mg/L以下。双沟和三沟交替运行2种模式均可以作为DE氧化沟提标改造的备选工艺。

关键词: DE型氧化沟, 双沟、三沟交替运行, 底曝

CLC Number: 

• X703.1