低温硝化活性污泥的富集及其生物强化效果

Effect of Enrichment and Bioaugmentation on Nitrifying Activated Sludge under Low Temperature

为解决冬季生物处理系统硝化功能差的问题,采用膜生物反应器(MBR)富集低温硝化污泥,分析富集前后微生物种群变化,考察在5、10、15、20℃下的氨氧化速率变化,探究低温硝化污泥(10℃)及中温硝化污泥(25℃)对受低温冲击的生物处理系统硝化功能的强化效果。结果表明:一般好氧池中的活性污泥在10℃和高氨氮负荷驯化后,可富集获得硝化活性为66 mg/(L·h)的低温硝化污泥;富集198 d后,其硝化杆菌属(Nitrobacter)和亚硝化单胞菌属(Nitrosomonas)的相对丰度提高了43倍和42倍;该硝化污泥在10~20℃的环境下,其硝化活性随温度的升高而升高,在5℃环境下,其氨氧化速率为10℃时的48%。对比低温和中温硝化污泥强化受7~8℃冲击的生物处理系统时,发现投加低温硝化污泥的生物处理系统5 d后,其氨氮去除率上升至99%以上;而投加中温硝化污泥的生物处理系统,则需20 d,且亚硝氮有明显积累,这说明采用与被强化体系温度差小的硝化污泥,能更快地恢复污水生物处理系统的硝化功能。

Low-temperature nitrifying activated sludge of(NAS-L)was enriched in a membrane bioreactor(MBR)to address the challenge of low nitrification activities in winter times.The dynamics of microbial community structure and ammonium-oxidizing rates were investigated during the enrichment of NAS at 5,10,15℃and 20℃.Bioaugmentation effects of NAS-L and NAS enriched at medium temperature(NAS-M)on biological nitrification system suffered from low-temperature shock were evaluated.The results showed that using the strategy of high ammonium loading rates,NAS-L with high nitrification activity of 66 mg/(L·h)was successfully enriched from common aerobic activated sludge at 10℃.After being enriched for 198 days,relative abundances of Nitrobacter and Nitrosomonas were enhanced by 43 times and 42 times,respectively.Nitrifying activity of NAS-L rose with the temperature under 10~20℃,and nitrification activity reduced by 48%when the temperature dropped from 10℃to 5℃.Besides,bioaugmentation test on biological nitrification reactor suffered from low-temperature(7~8℃)shock showed that the reactor inoculated with NAS-L achieved 99%of ammonia nitrogen removal within 5 days while 20 days were required and nitrite accumulation was observed for the reactor inoculated with NAS-M.These results demonstrated that nitrification activity was recovered faster by the bioaugmentation of NAS enriched at temperature closer to that of target reactor.