氧化沟不同分区脱氮除磷研究

STUDY ON THE EFFICIENCY OF BIOLOGICAL NITROGEN AND PHOSPHORUS REMOVAL OF DIFFERENT A/O PARTITIONING ZONES IN OXIDATION DITCH

采用混合反应器模拟氧化沟运行方式,探讨氧化沟不同好氧缺氧分区对脱氮除磷效果的影响。结果表明,在分点曝气氧化沟系统中氧传质推动力大,溶氧效率高,在相同的供氧条件下,其一个循环的好氧区比分段曝气系统好氧区长,但是分点曝气系统有机物耗氧多,DO浪费大,而分段曝气溶氧效率低,但DO的有效利用率(用于脱氮除磷)高,二者硝化能力相当,NH4+-N去除率分别为96.68%和97.03%,硝化菌活性分别为4.65、4.66 mg.g-1.h-1。在好氧区和缺氧区比例相同的条件下,分区越多,有机物被好氧异养菌利用的越多,脱氮除磷效果越差。分区减少,可以有效地增加反硝化菌对碳源的利用,对提高脱氮效果更有利。在同样的供氧条件下,分段曝气单个A/O分区长,反硝化菌和聚磷菌对碳源利用多,脱氮除磷效果优于分点曝气,在满足硝化的前提下,缺氧区和好氧区比例越大,碳源被利用的越完全,对脱氮除磷越有利,DO的有效利用率也越高,此时越接近于前置缺氧-好氧(A/O)工艺。

The oxidation ditch operation mode was simulated by the completely mixed reactor and the influence on nitrogen and phosphorus removal by different A/O partitioning zones was explored.The results showed that the oxygen was dissolved more efficiently with longer Aerobic region,but more DO was consumed by organic pollutants which caused wasting oxygen in the dispersing positions aeration mode.However,DO utilization efficiency for nitrogen and phosphorus removal was high in the step aeration.Both nitrification abilities were equal with NH4＋-N removal efficiency of 96.68% and 97.03%,respectively.Nitrifying bacteria activity were 4.65 mg·g-1·h-1 and 4.66 mg·g-1·h-1,respectively.Under the same ratio of aerobic zones and the anoxic zones,more the A/O partitioning zones were,poorer the nitrogen and phosphorus removal effect was,because COD was wasted by heterotrophic bacteria.Less A/O partitioning zones were more beneficial to nitrogen removal.The nitrogen and phosphorus removal efficiency in the step aeration was higher than in the dispersing positions aeration under the condition of same oxygen supply.On the condition of sufficient nitrification,larger the ratio of anoxic zones and aerobic zones was,more COD was utilized which was more beneficial to nitrogen and phosphorus removal and produced higher utilization efficiency of DO in the step aeration.This operation mode was similar to front oxygen-aerobic（A/O） process.