活性污泥法和生物膜法SBR工艺亚硝化启动和稳定运行性能对比

Comparison of Start-up and Stable Performance of Nitritation in Activated Sludge and Biofilm Processes in a SBR

在室温(25℃)条件下,同时启动活性污泥和生物膜SBR亚硝化反应器并稳定运行后,探究延长水力停留时间(HRT)和溶解氧(DO)对两工艺性能破坏与恢复的影响.结果表明,活性污泥反应器更易启动亚硝化,但当DO为2~2.5 mg·L^(-1)时亚硝化被破坏,且通过降低DO至0.5~1 mg·L^(-1)可恢复性能,而生物膜则基本不受DO影响.延长HRT均会破坏两种工艺的稳定运行,活性污泥法相比于生物膜法,其抵抗力较差但缩短HRT后恢复性能快于生物膜法.随后不断降低温度(20、15、10℃),探究DO和温度对亚硝化稳定的协同作用,结果表明温度的降低会破坏亚硝化的稳定运行,但通过DO浓度的降低可以弥补温度降低带来的不利影响,另外发现在温度大于20℃时,活性污泥法实现亚硝化速率优于生物膜法,而在低温条件(15℃以下),生物膜法更容易实现亚硝化的稳定运行,活性污泥法在10℃时,几乎没有处理氨氮的能力.通过分子微生物学分析证实了以上结论,并且发现在并不完全淘洗净NOB的条件下,也可以实现亚硝化的稳定运行.

This study investigates the effect of increased hydraulic retention time （ HRT） and dissolved oxygen （ DO） on the destruction and restoration of the performance of activated sludge and biofilm sequencing batch reactor （ SBR） nitritation after the processes were simultaneously started up and stably operated at room temperature （25℃ ）. The results showed that was easier to start nitritation in an activated sludge reactor, but nitritation was destroyed when DO was 2-2. 5 mg·L - 1 . The performance could be restored by reducing DO to 0. 5-1 mg·L - 1 . The biofilm process was not affected by DO. Prolonging HRT destroyed the stable operation of the two processes. Compared with the method of biofilm, the activated sludge method had less resistance, but restoring performance was better than for the biofilm process after shortening the HRT. Subsequently, the temperature （20, 15, and 10℃） was continuously reduced to investigate the synergistic effect of DO and temperature on nitritation stabilization. The results showed that the reduction of temperature destroyed the stable operation of nitritation, but the reduction of DO concentration could compensate for the adverse effects of temperature reduction. In addition, when the temperature was higher than 20℃ , the rate of nitritation in the activated sludge process was better than that in thebiofilm method. At low temperature （below 15℃）, a stable operation of nitritation was easier to achieve with the biofilm method. The capacity of the activated sludge process was hardly changed at 10℃. The above conclusions were confirmed by molecular microbiological analysis, and it was found that the stable operation of nitritation could be achieved without complete wash-out of the nitrite-oxidizing bacteria （NOB）.