UASB启动运行特征及互营丙酸氧化菌定量分析

为揭示升流式厌氧污泥床（UASB）反应器启动运行效能与互营丙酸降解菌群数量之间的关系，以稀释的玉米淀粉生产废水为底物，考察了UASB启动期的运行特征，并采用实时荧光定量PCR技术（qPCR）分析了互营丙酸降解菌群（丙酸氧化菌和产甲烷菌）的演替规律.结果表明，在进水COD 2000mg/L和水力停留时间（HRT）24h条件下，经过38d的连续运行，COD去除率达到了91.9%.当HRT分阶段缩短至8h时，比产甲烷速率达到了315LCH₄/（kg COD·d），且形成了沉降性能良好的颗粒污泥.qPCR检测结果表明，至少有5种已鉴定的丙酸氧化菌存在于UASB反应器中.Pelotomaculum propionicum为接种污泥中的主要丙酸氧化菌，约占检测到丙酸氧化菌总数的45.7%.它的数量随着HRT缩短不断减少.而Syntrophobacter sulfatireducens和S.wolinii的数量随着HRT缩短不断增加，并在启动完成时达到最大值，分别为1.3×10³，5.5×10³个16S rRNA基因拷贝数/ng DNA，演替成为成熟颗粒污泥中的优势丙酸氧化菌群.Methanobacterium和Methanosarcina为接种污泥中的主要氢营养型产甲烷菌和乙酸营养型产甲烷菌，其数量随着HRT的缩短而逐渐减少，而Methanospirillum和Methanosaeta的数量随HRT的缩短逐渐增加，成为成熟颗粒污泥中的优势产甲烷菌群.

The performance of UASB at startup and the quantitative analysis of syntrophic propionate-oxidizing bacteria

To reveal the relationship between the performance of upflow anaerobic sludge bed (UASB) reactor and syntrophic propionate-degrading consortia at startup, the operational characteristics during corn starch processing wastewater treatment in a UASB were investigated. The succession of syntrophic propionate-degrading consortia (propionate-oxidizing bacteria and methanogens) at startup was analyzed by quantitative real-time fluorescence polymerase chain reaction (qPCR). COD removal reached 91.9% after 38d operation under influent COD of 2000mg/L and hydraulic retention time (HRT) of 24h conditions. When HRT was shorten to 8h by stepwise, the specific methanogenic rate achieved 315LCH₄/(kg COD·d) and the granular sludge with good settling performance was formed. qPCR analysis showed that five identified species of propionate propionate-oxidizing bacteria existed in the UASB reactor. Pelotomaculum propionicum was the major propionate-oxidizing bacteria in inoculation sludge, accounting for 45.7% in detectable propionate-oxidizing bacteria. Its number was reduced as HRT shorting. However, the quantity of Syntrophobacter sulfatireducens and S. wolinii were increased as HRT decrease. The maximum with 1.3×10³ and 5.5×10³ 16S rDNA copies/ng DNA was reached in the end of startup, becoming the dominant propionate-oxidizing bacteria in the granular sludge. Methanobacterium and Methanosarcina were the dominant hydrogenotrophic and acetotrophic methanogens in the inoculation sludge. Their numbers were gradually reduced as HRT decrease. The quantity of Methanospirillum and Methanosaeta were increased, being the predominant methanogens in the granular sludge.