Innovation of waste-to-energy system by upgrading anaerobic digesters for sewage sludge

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K23528
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
• Research Institution: Tohoku University
• Principal Investigator: Qin Yu 東北大学, 工学研究科, 助教 (80853241)
• Project Period (FY): 2019-08-30 – 2021-03-31
• Keywords: 下水汚泥 / 嫌気性消化 / 水素発酵 / メタン発酵 / 熱処理 / 後処理 / 循環式二相消化

Outline of Final Research Achievements

This study focuses on expanding the potential of the existing anaerobic digester for sewage sludge, discussing the efficiency improvement of the waste-to-energy system by introducing the co-digestion method and post-treatment, and aiming at establishing a practical system. First, the effect of thermal post-treatment of digestate was examined by batch tests. The optimal condition was confirmed as 80°C for 60 min, improving methane yield by about 15%. Then, co-digestion of sewage sludge and paper waste was conducted by the continuous experiment. The optimal condition was obtained when solid content was added to 10% and the difference of mechanism in different processes was investigated. Moreover, the low-cost hydrogen fermentation process was operated. The effect of recirculation ratio on the process was investigated and the distributions of degrading activity and microbial community were discussed.

Free Research Field

環境保全工学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は実用化できれば、従来の下水処理場に比べて、大幅なコストダウンが実現でき、下水処理場より余剰電力を売電することが可能となる。このような経済性の高い革新的な技術を普及することで、エネルギー消耗を低減でき、環境負荷低減、地域の活性化、自然との共生や循環型社会の形成などの課題にも貢献可能となる。この効率的な廃棄物エネルギー化システムは日本社会の長期発展による脱炭素社会へ移行する際、今後の国際的な発展潮流を牽引していく技術の一つになると信じる。