聚甲醛废水的生物强化处理及微生物种群动态分析

Bioaugmentation treatment of polyoxymethylene(POM) wastewater and the dynamics of microbial community

聚甲醛工业废水含有甲醛、三聚甲醛和酚类等有害物,而且盐分和COD也较高,很难实现生物处理至达标排放.在聚甲醛污水厂建立中试系统并接种活性污泥,同时投加了经筛选的三聚甲醛降解菌Bacillus methylotrophicus和甲醛降解菌Candida maltosa、Pseudomonsa putida组成的复合菌剂,进行了聚甲醛、甲醛等有毒物质的选择性生物强化,通过温度梯度凝胶电泳(PCR-TGGE)技术对污水反应器进行了微生物群落结构分析,并与污水厂同期出水进行对照研究.结果表明,在投加复合菌剂的强化生物系统中,最终出水的甲醛、三聚甲醛(Trioxane,TOX)和COD降解率分别在97.8%、94.2%和92.6%以上,且系统表现出更高稳定性和抗冲击负荷能力.PCR-TGGE图谱表明,非生物强化系统中未检测到B.methylotrophicus,而该菌在生物强化系统中的活性一直得以维持,其对有毒物质的持续降解解除了其它微生物群落的抑制因子,污泥活性有效增强,说明该菌及复合菌剂确实对TOX及甲醛等毒性物质可有效降解,选择性生物强化可成为工业污水处理的可靠手段之一.

The biotreatment of polyoxymethylene （POM） wastewater with high salinity and COD concentration is difficult to achieve discharge standard due to toxic components like formaldehyde, trioxymethylene （TOX） and phenols. A pilot scale system was established in a POM wastewater treatment supplemented with complex microbial inoculants build-up with TOX-degradingbacterium Bacillus methylotrophicus and formaldehyde-degrading bacteria, Candida maltose and Pseudomonsa putida. Effluent of original treatment facility at the corresponding period was taken as control. PCR-TGGE was used to analyze the microbial community dynamics of two systems during the whole operation process. The experimental results indicate that the degradation of formaldehyde, TOX and COD achieved 97.8%, 94.2% and 92.6%, respectively, in the bioaugmentation system. The enhanced system also showed high stability and high shocking tolerance. The PCR-TGGE results indicate the strain B. methylotrophicus maintained in the system and enhance sludge activity by continuously depredating toxic components. This study shows that the complex microbial inoculants could degrade TOX and formaldehyde effectively, and bioaugmentation could be a reliable way for the treatment of industrial wastewater.