A~2/O-曝气生物滤池工艺处理低C/N比生活污水脱氮除磷

以低C/N比实际生活污水为研究对象,重点考查了A2/O-曝气生物滤池生化系统的脱氮除磷特性.同时,考虑到A2/O工艺的主要功能是除磷及反硝化,而曝气生物滤池则以硝化为目的.因此,通过缩短A2/O的泥龄,可将硝化过程从A2/O中分离出去,让曝气生物滤池完成硝化,实现硝化菌和聚磷菌的分离,并解决了硝化菌和聚磷菌泥龄之间的矛盾.试验结果表明,该生化系统可实现有机物、氮和磷的同步去除.在平均C/N比为4.2,内回流比R为250%的条件下,平均进水COD、TN、TP分别为239.9、57.3和5.1mg·L-1,平均最终出水COD、TN、TP分别为34.1、13.3和0.1mg·L-1,去除率分别为85.8%、76.9%和98.3%.曝气生物滤池对氨氮几乎保持了100%的去除率.序批试验表明,反硝化聚磷菌占聚磷菌的比例为40.5%.

Biological phosphorus and nitrogen removal in low C/N ratio domestic sewage treatment by a A2/O-BAF combined system

The behavior of biological phosphorus (P) and nitrogen (N) removal in a lab-scaled anaerobic/anoxic/oxic (A²/O)-biological aerated filter (BAF) combined system were investigated during the treatment of real domestic sewage with low C/Nratio.In order to solve the conflict of sludge retention time (SRT)between nitrifiers and polyphosphate-accumulating organisms(PAOs),a short SRTwas applied in the A²/Oreactor to wash out the nitrifiers.Therefore,in the system,the A²/Oreactor was mainly used for Premoval and denitrification and the BAFreactor was used for nitrification.The experimental results clearly showed that COD,Nand Pcan be simultaneously removed in this combined system.When the C/Nratio was 4.2 and the internal recycle ratio was 250%,the concentrations of COD,total nitrogen (TN) and total phosphorus(TP)were reduced from 239.9 mg·L^-1,57.3 mg·L^-1 and 5.1 mg·L^-1 in the raw waste water to 34.1 mg·L^-1,13.3 mg·L^-1 and 0.1 mg·L^-1 in the effluent,respectively.The removal efficiencies of COD,TNand TPreached to 85.8%,76.9% and 98.3%,respectively.In addition,almost 100% ammonium nitrogen removal efficiency was achieved in the BAFreactor.Batch tests showed that the population of denitrifying phosphate-accumulating organisms (DPAOs) was up to 40.5% of the total PAOs.