Fumie YOSHIKAWA

Sludge characteristics and performance of UASB process treating propionate-rich artificial wastewater


Hideki HARADA, Akiyoshi OHASHI, Hiroyuki IMACHI



�@Compared to mesophilic process, thermophilic anaerobic wastewater treatment is vulnerable to environmental changes and is difficult to control. Especially, when the system is unstable, propionate is accumulated. However, the problems not yet solved.
In order to solve the problem of propionate accumulation, it investigated on the treatment characteristics of UASB was carried out, which was fed with propionate-rich artificial wastewater.

�@Maximum organic loading rate achieved for mesophilic and thermophilic UASB process was above 40 kgCOD.m-3.d-1 and 20 kgCOD.m-3.d-1, respectively, while maintaining the organic removal efficiency at 98% and 90%, respectively.

�@16S rRNA gene-based cloning analyses for microbial communities in thermophilic and mesophilic UASB sludge granules treating artificial wastewater solely consisting of propionate revealed that the dominant clones were different in thermophilic and mesophilic clone libraries, respectively. In the thermophilic clone libraries, a large number of clonal sequences retrieved were Pelotomaculum species-type sequences, which were isolated and characterized as a solely thermophilic propionate-oxidizing syntroph.