EGSB处理垃圾焚烧渗沥液及其微生物群落变化

研究了处理垃圾焚烧渗沥液的膨胀颗粒污泥床(EGSB)反应器在超负荷运行前后厌氧颗粒污泥的微生物群落结构变化.在实验室启动并运行了处理垃圾焚烧渗沥液的EGSB反应器,逐渐提高反应器的有机负荷(OLR),当OLR为23.1kgCOD/(m3×d)时,COD去除率保持在93%以上.当OLR继续升至24.5kgCOD/(m3×d)时,COD去除率迅速下降至73.9%,且出水挥发酸大量增高,反应器进入超负荷运行状态.对反应器中厌氧颗粒污泥进行克隆文库分析,发现经过11d的超负荷运行,污泥中的微生物群落结构发生了明显的变化,古菌的优势菌从产甲烷髦毛菌(含量为68.4%)变为产甲烷微菌(含量为51.9%);细菌的优势菌一直是低GC革兰氏阳性菌(含量约56%),且大多数属于具有形成芽孢特性的Clostridiales目.EGSB反应器超负荷运行导致乙酸营养型古菌大量死亡,小分子有机酸大量积累,处理效率急剧下降.

Treatment of fresh leachate from MSW incineration plant by EGSB and dynamics of microbial community

This paper investigated dynamics of microbial community in anaerobic sludge in an expanded granular sludge bed (EGSB) reactor treating fresh leachate from a municipal waste solid incineration plant under overloaded conditions. A lab-scale EGSB reactor was operated for the treatment of fresh leachate with gradual increases in the organic loading rate (OLR). The removal efficiency of COD was over 93% when the OLR increased to 23.1 kgCOD/(m3×d). As the OLR increased further to 24.5 kgCOD/(m3×d), the removal efficiency of COD decreased to 73.9% immediately with a marked rise of volatile fat acids in the effluents, indicating that the reactor was overloaded. By analyzing sludge samples through clone libraries, the microbial community in the sludge varied significantly after 11d of overloaded operation. The dominant group of archaea shifted from Methanosaetaceae (68.4%) to Methanomicrobiaceae (51.9%). The dominant group of bacteria was Firmcutes all the time with a proportion of aproximately 56%, most of which were spore-forming bacteria belonging to the order of Clostridiales. Overloaded operation of EGSB resulted in severe inhibition of acetoclastic methanogens, causing an obvious accumulation of small organic acids and a sharp decline in the treatment efficiency.