分段进水工艺水力停留时间的优化与运行策略

Optimization and Operation Strategy of Hydraulic Retention Time in Modified Four Step-feed Process

本研究采用改良A/O四点分段进水工艺处理低浓度、低碳氮比市政废水。在进水流量分配比为20%∶35%∶35%∶10%、缺氧/好氧体积比为1∶1、SRT为15d、污泥回流比为75%条件下,通过调整不同的水力停留时间(HRT),研究HRT对污染物去除性能的影响以及确保出水污染物达标的最短HRT与运行策略。结果表明:HRT从8.7h降低至6h,对COD、TP的去除基本无影响,但出水氨氮、TN浓度随之升高,并且进水碳源有效利用率以及好氧段同步硝化反硝化(SND)效果随之降低。当HRT为6h时,通过控制好氧段DO为1.0～1.5mg.L-1联合在好氧段投加悬浮填料的策略,出水COD、氨氮、TN、TP浓度分别为25.92、1.98、14.5和0.47mg.L-1;悬浮填料的投加可以优化出水氨氮和好氧段SND效果,且SND比例达到22%,但对进水碳源有效利用率的提高不明显。

A pilot modified four step-feed process was applied to deal with weak municipal wastewater.After 133 days of continuous operation with different hydraulic retention time(HRT) and operation strategy,the results are obtained as the following:(1)When HRT is reduced from 8.7h to 6h,there is almost no effect on performance of COD and TP,but would lead to increase effluent NH4+-N and TN.Meanwhile,the influent carbon source utilization and simultaneous nitrification and denitrification(SND) are correspondingly decreased.(2)When HRT is 6h,the DO concentration in areobic zones are controlled between 1.0-1.5 mg·L-1 and adding suspended carriers in aerobic zones,the effluent performance of COD,NH4+-N,TN and TP are 25.92,1.98,14.5and 0.47 mg·L-1 respectively.(3)Suspended carriers can be used to optimize the effluent ammonia and SND performance,and achieve 22% of TN removed through SND with suspended carriers.However,it's not obvious for suspended carriers to improve the influent carbon source effective utilization.