The research of the sludge treatment process combining anaerobic digestion with aerobic digestion using the microbial community of which decomposability of the protein is high.

• Project/Area Number: 13650597
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Civil and environmental engineering
• Research Institution: Shinshu University
• Principal Investigator: MATSUMOTO Akito Shinshu University, faculty of engineering, associate professor, 工学部, 助教授 (30252068)
• Project Period (FY): 2001 – 2003
• Project Status: Completed (Fiscal Year 2003)
• Budget Amount: ¥3,000,000 (Direct Cost: ¥3,000,000); Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000); Fiscal Year 2002: ¥400,000 (Direct Cost: ¥400,000); Fiscal Year 2001: ¥2,100,000 (Direct Cost: ¥2,100,000)
• Keywords: Bacillus species / compost / aerobic digestion / digestion temperature / anaerobic-aerobic digestion / aerobic-anaerobic digestion / FISH / Bacillus subtilis / Bacillus属 / VSS / VSS分解率 / 最適曝気量 / 流入基質濃度 / 熱処理 / ATP / 嫌気性消化

Research Abstract

The experiment was carried out with the sludge treatment process of combining anaerobic digestion with aerobic digestion in order to improve the sludgy process efficiency. The compost that contained the Bacillus species was used as seed sludge of aerobic digestion. To begin with, the sludge treatment performance of the process combining aerobic digestion with anaerobic digestion as pretreatment (aerobic-anaerobic digestion process) and that of the process combining aerobic digestion with anaerobic digestion as posttreatment (anaerobic-aerobic digestion process) was compared. Next, the effect of aerobic digestion temperature of anaerobic -aerobic digestion process on the process efficiency was examined. That is to say, the compost was put into anaerobic digested sludge as seed sludge, and aerobic digestion was carried out at various digestion temperatures (20℃,30℃,50℃). Finally, aerobic digestion was carried out in various substrates, and whether Bacillus subtrlis (a kind of the represe ntative Bacillus species) existed in each aerobic digester was examined by FISH (fluorescent in situ hybridization) method.
The following conclusion can be made :
・Anaerobic-aerobic digestion process was more possible stabilized processing than aerobic-anaerobic digestion process.
・The largest VSS degradation rate in aerobic digestion of anaerobic -aerobic digestion, process was 52% at 20℃,52 and 42% at 30℃ and 61% at 50℃. In addition, the overall VSS degradation rate through anaerobic -aerobic digestion process was over 80% at each digestion temperature. Still, the nitrification hardly happened in the operation except for 30℃.
・In aerobic digestion of anaerobic-aerobic digestion process, the effect of digestion temperature could not be observed at the largest VSS decomposition rate in the operation for 3 days, the decomposition rate increased, as digestion temperature rises after the operation for 7 days.
・It was possible to detect Bacillus subtilis only from the digester cultivated in the sucrose substrate.