High efficiency and stability in the UASB fed with domestic sewage by high abundance of anaerobic protozoa 1

采用18S rRNA基因克隆技术，对处理城市生活污水的UASB中试装置进行厌氧原生动物的鉴定。每个物种的丰度在三年内通过显微镜直接计数来测量。弯曲Metopus tortorus，古Metopus paleformis，压缩Trimyema compressum作为原生动物在UASB中大量存在时占优势。原生动物总细胞数随污水温度的变化而变化，秋季达到11x103个细胞/mL，春季达到0个细胞/mL。鱼类分析显示，在一个原生动物细胞中，氢利用产甲烷菌作为其共生细菌存在于104个细胞的水平。Metopus sp通过捕食来减少UASB的MLSS。

Identification of anaerobic protozoa in an UASB pilot plant treating domestic municipal sewage was carried out by 18S rRNA gene cloning to clear how many species existed in. Abundances according to each species were measured by microscopic direct counts throughout three years. Metopus contortus, Metopus palaeformis, Trimyema compressum were predominance as a protozoan in the UASB when present in large numbers. Total cell number of the protozoa shifted with changes in temperature of the sewage, and up to 11x103 cells/mL (fall) and became 0 cells/mL (spring). FISH analysis to Metopus contortus revealed that hydrogen utilizing methanogen present at a level of 104 cells in one protozoan cell as their symbiotic bacteria. Metopus sp played a important role to reduce MLSS in the UASB by their predation.