SBR法常、低温下生活污水短程硝化的实现及特性

采用序批式反应器(SBR)处理实际生活污水,通过实时控制好氧曝气时间,在常温下快速实现短程硝化,并在低温下长期维持稳定的短程硝化.结果表明,随着温度逐渐降低,比氨氧化速率略微减缓,27℃的平均比氨氧化速率是13℃时的1.68倍,但亚硝化积累率始终维持在90%以上,该温度区间内氨氧化反应的温度系数为1.051.通过荧光原位杂交(FISH)技术对低温下维持稳定短程硝化的污泥进行种群分析发现,实时控制策略为氨氧化菌(AOB)成为优势硝化菌群创造了有利条件,AOB的相对百分含量达到8%~9%,而亚硝酸盐氧化菌(NOB)逐渐被淘洗出反应器.在低温下要实现短程硝化,可首先在常温下利用好氧曝气时间实时控制实现亚硝态氮的积累和AOB的优势生长,然后通过逐渐降温使AOB适应在低温下生长.

Partial nitrification via nitrite at ordinary and low temperatures in an SBR treating domestic wastewater

Through real-time aeration duration control, partial nitrification was carried out in a lab-scale SBR at normal temperatures and maintained for a long time even at low temperatures. The specific ammonia oxidation rate would be reduced with decrease of the temperature. The average specific ammonia oxidation rate at 27℃ was 1.68 times of that at 13℃. The temperature coefficient of ammonia oxidation reaction in the reactor was ascertained 1.501 according to the Arrhenius expression. When nitrite accumulation ratio was steadily kept over 90%, fluorescence in situ hybridization (FISH) was used to detect the sludge population structure, which showed the proportion of the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) was 8%~9% and lower than 0.5%, respectively. The real-time control strategy had a positive effect on the enrichment of AOB and the limitation or wash-out of NOB. An advisable start up strategy to operate a partial nitrification system at low temperatures could have two steps, obtaining firstly the selective enrichment of AOB as well as the washout of NOB by real-time aeration duration control under ordinary temperatures, and then making the biomass slowly adapt to low temperatures.