新型后置反硝化工艺处理低C/N(C/P)比污水脱氮除磷性能研究

从内碳源有效利用角度出发,开发了新型连续流后置反硝化AOA工艺,将厌氧段混合液按一定比例分流至缺氧段,从而强化缺氧段反硝化除磷作用.进水NH₄⁺-N和PO₄^3--P浓度保持在(38.31±2.03) mg·L^-1和(5.74±0.13) mg·L^-1,在不同运行阶段进水COD分别控制在300 mg·L^-1和250 mg·L^-1,考察了AOA工艺处理低C/N(C/P)比污水过程影响因素.当进水C/N比和C/P比分别为7.41±0.26和52.36±1.25时,通过将SRT由10 d延长到16 d,系统TN和PO₄^3--P去除率分别稳定在65.86%±2.06%和90.00%±3.97%;当进水C/N比、C/P比降至6.14±0.32和43.40±1.37时,在SRT为16 d条件下,将A/O/A体积比由1/3/1调整为1/2/2,TN和PO₄^3--P去除率分别升至69.76%±3.36%和98.73%±1.82%.结果表明,采用控制SRT、调整好氧/缺氧HRT等策略,可保证处理低C/N(C/P)比污水AOA工艺高效稳定运行.

Nutrient removal performance of a novel post-anoxic process in treating wastewater with low C/N(C/P) ratios

Based on the efficient utilization of internal carbon source, a novel post-anoxic continuous anaerobic/aerobic/anoxic (AOA) process was developed. In this process, part of the anaerobic mixed liquor was transferred to the post-anoxic zone in order to enhance the denitrifying phosphorous removal. The influent NH₄⁺-N and PO₄^3--P concentrations were maintained at (38.31±2.03) mg·L^-1 and (5.74±0.13) mg·L^-1, and the influent COD concentration was controlled at 300 mg·L^-1 and 250 mg·L^-1 during different operating periods. The effect of operating parameters on nutrient removal performance of the AOA process in treating the wastewater with low C/N and C/P ratios was also investigated. It was found that with influent C/N and C/P ratios of 7.41±0.26 and 52.36±1.25, respectively, the removal efficiencies of TN and PO₄^3--P reached 65.86%±2.06% and 90.00%±3.97% along with the SRT from 10 d to 16 d. When influent C/N and C/P ratios decreased to 6.14±0.32 and 43.40±1.37, the removal efficiencies of TN and PO₄^3--P increased to 69.76%±3.36% and 98.73%±1.82% via the change of A/O/A ratio from 1/3/1 to 1/2/2. It was therefore concluded that the nutrient removal performance of the AOA process in treating wastewater with low C/N and C/P ratios could be stable by controlling SRT as well as aerobic and anoxic HRTs.