Development of an innovative method for decreasing and insolubilizing arsenic in sediment from Dam reservoir

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19859
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 64:Environmental conservation measure and related fields
• Research Institution: Iwate University
• Principal Investigator: Ito Ayumi 岩手大学, 理工学部, 教授 (90312511)
• Co-Investigator(Kenkyū-buntansha): 石川 奈緒 岩手大学, 理工学部, 准教授 (10574121)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: ヒ素汚染修復

Outline of Final Research Achievements

The media containing arsenate or ferric oxide were inoculated with activated sludge to cultivate arsenate reducing bacteria and iron reducing bacteria, respectively. Arsenate concentration was decreased, while arsenite one was increased. And dissolved ferrous concentration was increased. These results suggested the presence of both reducing bacteria in activated sludge and their utilization to dissolve arsenic in sediment.
Both reducing bacteria from the cultivation were added to the sediment containing arsenic from reservoir and cultivated under anaerobic condition, which resulted in an increase in dissolved arsenic concentration. This suggests that both reducing bacteria would be useful for the remediation of sediment polluted with arsenic.

Free Research Field

環境衛生工学

Academic Significance and Societal Importance of the Research Achievements

本研究成果はFeやAlと共存する堆積物中のAsを微生物学的に低減するための新たな学術的知見を提供する。
将来における水環境リスクの回避や埋立地確保の困難性、さらには資源循環および貯水池の持続可能性の観点から、将来の対策手法の一つとして、Asを含有する堆積物を適切に処理して土木資材として有効利用できることが望まれる。そのために堆積物中のAs含有量を低減するとともに、有効利用後に再溶出しにくい状態まで未利用資源である浄水汚泥を活用して不溶化するための新規低コスト型処理手法を開発するうえで本研究成果は役立つと考えられる。