Development of vermicomposting technology using sewage sludge and grass clippings

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K14550
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 41030:Rural environmental engineering and planning-related
• Research Institution: Public Works Research Institute
• Principal Investigator: Yamasaki Yukiyo 国立研究開発法人土木研究所, 土木研究所(先端材料資源研究センター), 研究員 (10647382)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 汚泥堆肥化 / 貧毛類 / 下水汚泥 / 刈草

Outline of Final Research Achievements

The purpose of this research was to develop a sludge treatment technology that utilizes earthworms, sludge, and mowing.
When the system drained water from the sludge, earthworms were able to reproduce in the sludge before dehydration. When primary sludge generated at the wastewater treatment plant was used as food, earthworms were able to breed, laying large number of eggs. When excess or digested sludge was used as food, earthworms were propagated by adjusting the sludge input amount or using the mixing method. Layer and mowing mixing increased the viability of earthworms. The results of this study showed that earthworms can be propagated and composted using the regional biomass of sewage sludge or grass clippings.

Free Research Field

環境工学

Academic Significance and Societal Importance of the Research Achievements

下水処理場における汚泥の発生量削減や有効利用方法の開発、河川堤防等の刈草等の活用は、省コスト化や、資源活用の点で、常に課題である。本研究では、ミミズを用いた下水汚泥の堆肥化による、低エネルギーかつ低コストな下水汚泥利用技術の開発を目指した。
本研究において、脱水前の下水汚泥を、ミミズ飼育に活用できることを示し、脱水にかかるエネルギー削減の可能性を示した。汚泥の種類毎のミミズ飼育方法の一案を示し、汚泥の処分にかかるエネルギーの削減または有効利用につながる可能性を示した。また、刈草の活用が、堆肥化、ミミズの成長の安定化に有用な可能性を示し、未利用のバイオマスの活用の可能性を示すことができた。