抄録
Two continuous flow experiments were conducted using self-immobilized methanogenic cells reactors, i. e., up flow anaerobic sludge blanket reactors to investigate its process performance. The first experiments were made at 25°C both with a mixture of starch and sucrose as a substrate at a influent COD of 3, 000 mg·l-1 (refer to as Run 1) and with molasses at a influent COD of 6, 000 and 2, 200 mg·l-1(Run 2). Maximum allowable loading rates were evaluated to be 25 kgCOD·m-3·day-1 (corresponding to HRT of 2.9 hrs) for Run 1, and to be 14 and 20 kgCOD·m-3·day-1 for a influent COD of 6, 000 and 2, 200 mg·l-1, respectively, for Run 2. The second experiments were made at 35°C both using a mixture of volatile fatty acids at a influent COD of 5, 000 mg·-1 (Run 3) and acetate at a influent COD of 3, 000 mg·-1 (Run 4), resulting that maximum loading rates were achieved at 70 (corresponding to HRT of 1.7 hrs) for Run 3 and at 25 kgCOD·m-3·day-1 (HRT of 2.9 hrs) for Run 4, respectively.
Comparison of microbial activity between granular sludges cultivated in Runs 1 to 4 indicated that methanogenic activity, ATP pool and F420 content were varied in the range of 0.3-1.7 kgCH4-COD. kgVSS-1·day-1, 0.046-0.355 mg·gVSS-1 and 0.032-0.39 mg·gVSS-1, respectively, which were 4-20 times, 1.1-87 times and 2-26 times greater than those of the original innocula of digested sewage sludge. Morphological observation of granular sludges by scanning and transmission electron microscopes revealed that both filamentous growth of methanothrix genus methanogens and excretion of extracellular biopolymer by acidogens take significant roles in granule formation.
