A2N2系统反硝化除磷性能的优化及稳定运行

摘要

The two-sludge denitrifying phosphorus removal system (A2N2) with "anaerobicitrification/anoxicitrification"operation mode was used to treat low C/N ratio real domestic wastewater in sequencing batch reactors (SBR). Through the operating condition optimization of A2/O-SBR and N-SBR unit, the system achieved efficient denitrifying phosphorus removal performance with the low carbon source sewage and solved the problem of high NH4+-N in A2N-SBR process. Experimental results showed that post-aeration was essential to the efficient nutrient removal performance and long-term stable operation of the A2N2-SBR. Complete denitrifying phosphorus uptake without aerobic phosphorus uptake at the anoxic stage of the A2N2-SBR was disadvantageous to the growth and reproduction of denitrifying phosphorus accumulating organisms (DPAOs). Anaerobic duration of 1.5h in the A2/O-SBR was ensured the complete oxidation of biodegradable COD, and nitrification duration of 5h in the N-SBR provided sufficient time for NH4+-N oxidation. With anaerobic phosphorus release of 1.5h, denitrifying phosphorus uptake of 2h, and aerobic phosphorus uptake of 0.5h in the A2/O-SBR unit, and the first nitrification of 5h and second nitrification of 1h in the N-SBR unit, the average effluent COD, NH4+-N, TN and PO43--P concentrations in the A2N2-SBR system was 46.2, 0.82, 13.63 and 0.82mg/L, respectively. Simultaneous nitrogen and phosphorus removal was achieved in the novel A2N2-SBR system.%利用按“厌氧/硝化/缺氧/硝化”方式运行的双污泥反硝化除磷系统(A2N2),以低C/N值实际生活污水为研究对象,重点研究A2/O-SBR和 N-SBR 单元的运行条件优化过程中,各污染物去除的变化规律及系统的脱氮除磷性能.研究结果表明；完全反硝化除磷无好氧吸磷模式不利于反硝化聚磷菌(DPAOs)的生长繁殖,后曝气对保障 A2N2系统高效稳定的脱氮除磷效果及长期稳定运行必不可少；A2/O-SBR 单元厌氧1.5h,基本完成了可生物降解COD的氧化；N-SBR单元硝化5h,实现了NH4+-N的完全硝化；在A2/O-SBR单元厌氧释磷1.5h,反硝化除磷2h,好氧吸磷0.5h,N-SBR单元一次硝化5h,二次硝化1h的条件下,系统平均出水COD、NH4+-N、TN和PO43--P浓度分别为46.2、0.82、13.63、0.3mg/L,满足了同步脱氮除磷的要求.