Granular sludge formation and it`s activity change are the most important factors in achieving successful start-up and operation of UASB reactor. Nevertheless, the detailed mechanism is still unknown.
On the basic of the experiments in laboratory-scale UASB reactor, the effect of hydrogen partial pressure on sludge granulation was evaluated.
Size distribution method and specific metabolic activity of the sludge with the operation time were used as a means for estimating the degree of the sludge granulation.
At the constant hydrogen loading, the granulation increased as starvation periods in hydrogen supply increased, resulting in high organic removal efficiency. It was evidient that hydrogen play very important role in granulation and sludge granulation was achieved through mutual symbiosis between hydrogen utilizing bacteria and hydrogen producing bacteria under the hydrogen deficient conditions.

• 정병곤(군산대학교 해양환경학과) | Byung-Gon JEONG
• 이헌모(동의공업전문대학 환경공업과) | Heon-Mo LEE
• 양병수(부산수산대학교 환경공학과) | Byung-Soo YANG