Decomposition of wood in soils generated by a disaster as a ground material with unnecessary nitrogen

Research Project

Project/Area Number	17K00600
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Environmental engineering and reduction of environmental burden
Research Institution	Nagasaki University
Principal Investigator	ASAKURA Hiroshi 長崎大学, 水産・環境科学総合研究科(環境), 准教授 (00391061)
Project Period (FY)	2017-04-01 – 2020-03-31
Project Status	Completed (Fiscal Year 2019)
Budget Amount *help	¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000) Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Keywords	災害発生土砂 / 木くず / 分解 / 堆肥化 / 窒素 / 木材腐朽菌 / 酸素消費速度 / 窒素源 / 硝酸塩 / 木材 / 災害廃棄物 / 分別土 / 有機炭素削減 / アンモニア性窒素
Outline of Final Research Achievements	In this study, in order to utilize soils generated by a disaster as a ground material, we developed reduction method for organic carbon by biodegradations such as composting and wood rotting fungi. Composting rate should be increased by nitrate addition at adequate quantity for wood composting. In a part of conditions, wood decomposition was accelerated with nitrate addition. The optimal conditions for wood decomposition by wood rotting fungi were found to be 30 degree Celsius and 60% of moisture. Since wood decomposition rates decreased by nitrate addition, nitrate addition was found to be inadequate for activity of wood rotting fungi.
Academic Significance and Societal Importance of the Research Achievements	木材腐朽菌による木質分解を促進する条件が分かったことは，実際の土壌中の分別土分解の実用化につながることであり，学術的に意義がある。分別土リサイクル時の環境保全のための有機炭素含有量上限基準の目安はあるものの，基準を超過する分別土は存在する。最終処分されて廃棄物埋立地の残余容量を消費することは，最終処分量削減の国の方針から逆行している。本研究成果から，分別土から木くず等有機炭素を削減可能であり，これによって分別土の有効利用が広がれば最終処分量の削減が可能である。