Non-thermal effect mechanism of microwave irradiation as a pretreatment for anaerobic digestion of sewage sludge

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15126
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22060:Environmental systems for civil engineering-related
• Research Institution: Tottori University of Environmental Studies
• Principal Investigator: Togari Taketo 公立鳥取環境大学, 環境学部, 准教授 (60803830)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: メタン発酵 / マイクロ波 / バイオガス

Outline of Final Research Achievements

Microwave irradiation was applied to sewage sludge to improve its degradation and biogas production in anaerobic digestion. In the batch experiments, the biogas production increased with microwave irradiation of excess sludge and digested sludge, even at low temperatures and low power.In the 375-day continuous experiment, biogas production from MW-irradiated excess sludge increased by 18.9% under the 10 W, 138 J/g-wet irradiation condition. The irradiation of 10% of the digested sludge in the tank with MW at 50 W and 90 J/g-wet resulted in an 12% increase in biogas production.These results indicate the possibility of a anaerobic digestion system with MW non-thermal effects.

Free Research Field

水環境工学

Academic Significance and Societal Importance of the Research Achievements

メタン発酵は地域で発生する有機性廃棄物からエネルギー回収可能な処理方式として有用な処理方法である．しかし，下水汚泥，特に水処理工程を経た余剰汚泥や，メタン発酵後の消化汚泥は，生ゴミなどに比べて生分解性が小さく，バイオガス生成量も小さい．本研究の成果により，下水汚泥の生分解性を上げるための前処理として，低温・低出力のマイクロ波照射による効果が示された．メタン発酵における加温と同時に生分解性の向上が可能になるシステムなど，下水汚泥処理におけるエネルギー収支の改善への貢献が期待される．