不同曝气量和好氧时间下SPNDPR系统处理低C/N城市污水的脱氮除磷性能

Nitrogen and Phosphorus Removal from Low C/N Municipal Wastewater Treated by a SPNDPR System with Different Aeration and Aerobic Times

以低C/N城市污水为处理对象,采用延时厌氧(180min)/好氧运行的SBR反应器,通过调控曝气量[单位体积的反应器在单位时间内通过的气体的体积,单位为L·(min·L)^(-1).由0. 125 L·(min·L)^(-1)逐渐降低至0. 025 L·(min·L)^(-1)]和好氧时间(由3 h逐渐延长至6 h),考察了SPNDPR系统的深度脱氮除磷性能.结果表明,当曝气量为0. 025 L·(min·L)^(-1)、好氧时间为6 h时,SPNDPR系统出水NH_4^+-N、NO_2^--N、NO_3^--N和PO_4^(3-)-P浓度分别为0、8. 62、0. 06和0. 03 mg·L^(-1);出水TN浓度约为9. 22 mg·L^(-1),TN去除率高达87. 08%.当曝气量分别由0. 125 L·(min·L)^(-1)降至0. 100 L·(min·L)^(-1)和由0. 100L·(min·L)^(-1)降至0. 075 L·(min·L)^(-1)时,系统硝化速率均能恢复并稳定维持在0. 16 mg·(L·min)^(-1)左右.但曝气量继续降至0. 050 L·(min·L)^(-1)和0. 025 L·(min·L)^(-1)后,硝化速率分别降至0. 09 mg·(L·min)^(-1)和0. 06 mg·(L·min)^(-1)左右.随着曝气量的降低[由0. 125 L·(min·L)^(-1)依次降至0. 100、0. 075、0. 050、0. 025 L·(min·L)^(-1)]和好氧时间的延长(由3 h延长至6h),SPND脱氮性能逐渐增强,SND率由19. 57%升高至72. 11%,TN去除率逐渐升高(由62. 82%升高至87. 08%).降低曝气量和延长好氧时间后的SPNDPR系统,强化了厌氧段内碳源贮存与好氧段好氧吸磷、反硝化除磷、短程硝化、内源反硝化等过程的进行,实现了低C/N城市污水的深度脱氮除磷.

An anaerobic(180 min)/aerobic operated sequencing batch reactor(SBR)fed with urban sewage was optimized by regulating the aeration quantity to investigate the deep-level nitrogen(N)and phosphorus(P)removal.The amount of aeration was regulated by adjusting the volume of gas per unit volume of reactor passed in unit time,when the unit is L·(min·L)-1,from 0.125 L·(min·L)-1 gradually to 0.025 L·(min·L)-1,and aerobic times from 3 h to 6 h.The experimental results show that the effluent NH4+-N,NO2--N,NO3--N,and PO43--P concentrations of the optimized SPNDPR system were 0,8.62,0.06,and 0.03 mg·L-1.The effluent TN concentration was about 9.22 mg·L-1,and the TN removal efficiency was up to 87.08%.When the aeration quantity was decreased from 0.125 L·(min·L)-1 to 0.100 L·(min·L)-1;then decreased to 0.075 L·(min·L)-1,the nitrification rate of the system recovered and stabilized at 0.16 mg·(L·min)-1.However,when the aeration quantity continuously decreased to 0.050 L·(min·L)-1 and then to 0.025 L·(min·L)-1,the nitrification rate decreased to 0.09 mg·(L·min)-1 and 0.06 mg·(L·min)-1.With reduction of the aeration quantity[from 0.125 L·(min·L)-1 to 0.100,0.075,0.050 and 0.025 L·(min·L)-1]and extension of aerobic time(from 3 h to 6 h),the TN removal efficiency increased gradually from 62.82%to 87.08%,and the SND efficiency increased from 19.57%to 72.11%.It was proven that reducing the aeration quantity can enhance the SPND function and deep denitrification by the system was realized.By enhancing the anaerobic intracellular carbon storage and aerobic phosphorus uptake,denitrifying phosphorus removal,partial nitrification,and endogenous nitrification were achieved.The SPNDPR system,after reducing aeration and prolonging aerobic time,was able to realize deep-level denitrification and dephosphorization using low C/N urban sewage.