Elucidation of regrowth mechanism of opportunistic pathogens in drinking water and verification of their control strategies

• Project/Area Number: 17H04940
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Civil and environmental engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Kasuga Ikuro 東京大学, 大学院工学系研究科(工学部), 准教授 (20431794)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥23,270,000 (Direct Cost: ¥17,900,000、Indirect Cost: ¥5,370,000); Fiscal Year 2019: ¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000); Fiscal Year 2018: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2017: ¥13,780,000 (Direct Cost: ¥10,600,000、Indirect Cost: ¥3,180,000)
• Keywords: 微生物再増殖 / 日和見病原細菌 / 水道水 / 宅内給水 / 生分解性有機物 / 再増殖 / 細菌再増殖 / 宅内給水管 / 水道 / 給配水 / 給配水システム / 土木環境システム

Outline of Final Research Achievements

Chlorine residual diminishes during stagnation in premise plumbing, which can cause microbial regrowth. This study demonstrated that microbial community including Legionella spp. and Mycobacterium spp. increased after stagnation in premise plumbing. Additionally, we investigated organic matter supporting microbial regrowth in drinking water. In particular, the composition of organic matter migrating from polymeric plastic pipes and its impact on microbial regrowth was revealed.

Academic Significance and Societal Importance of the Research Achievements

人口減少が進む日本では、給水量の減少に伴って宅内での水道水の滞留が頻発し、微生物再増殖が顕在化することが懸念されている。しかし、わが国では微生物再増殖の実態について詳細なデータがない。本研究の学術的な意義は、日和見病原細菌の動態や微生物再増殖を促進する因子を明らかにした点である。水道水中の微生物再増殖に起因するリスクが低いことを確認できたことは社会的に有意義な知見ではあるが、微生物学的に安定な水道水質を実現することは潜在的なリスクを低減する上でも必要である。

Research Products

• [Journal Article] Impacts of Organic Matter Migrating from Pipe Materials on Microbial Regrowth in Drinking Water (2020)
  • Author(s): Iftita Rahmatika, Ikuro Kasuga, Futoshi Kurisu, and Hiroaki Furumai
  • Journal Title: Journal of Water and Environment Technology Volume: 18 Issue: 1 Pages: 45-53
  • DOI: 10.2965/jwet.19-078
  • NAID: 130007796200
  • ISSN: 1348-2165
  • Peer Reviewed / Open Access
• [Presentation] Molecular-level analysis of biodegradable organic matter supporting microbial regrowth in drinking water (2019)
  • Author(s): Ikuro Kasuga, Miyu Suzuki, Futoshi Kurisu, and Hiroaki Furumai
  • Organizer: 8th IWA Microbial Ecology and Water Engineering Specialist Conference
  • Int'l Joint Research
• [Presentation] Evaluation of organic compounds migrated from polyethylene and their impacts on microbial regrowth in drinking water (2019)
  • Author(s): Iftita Rahmatika, Ikuro Kasuga, Futoshi Kurisu, and Hiroaki Furum
  • Organizer: 8th IWA Microbial Ecology and Water Engineering Specialist Conference
  • Int'l Joint Research
• [Presentation] Drinking water quality management after treatment -Risks of microbial regrowth in distribution system and premise plumbing- (2019)
  • Author(s): Ikuro Kasuga
  • Organizer: The 9th International Forum Green Technology and Management
  • Int'l Joint Research / Invited
• [Presentation] What is going on in pipes? -A hot spot for microbial regrowth in drinking water- (2019)
  • Author(s): Iftita Rahmatika, Ikuro Kasuga, Futoshi Kurisu, and Hiroaki Furumai
  • Organizer: Water Environment Technology Conference 2019
  • Int'l Joint Research
• [Presentation] Control of microbial regrowth in premise plumbing -Challenge of aging water supply systems- (2019)
  • Author(s): Ikuro Kasuga
  • Organizer: Vietnam-Japan Science and Technology Towards Sustainable Development 2019
  • Int'l Joint Research / Invited
• [Presentation] Influence of water stagnation on microbial regrowth at different faucets in a building plumbing (2019)
  • Author(s): Ifitita Rahmatika, Ikuro Kasuga, Futoshi Kurisu and Hiroaki Furumai
  • Organizer: 第53回日本水環境学会年会
• [Presentation] Evaluation of biodegradable organic matter causing regrowth in drinking water (2017)
  • Author(s): Ikuro Kasuga
  • Organizer: The 3rd International Forum on Asian Water Environment Technology
  • Invited
• [Presentation] 非培養法を活用した迅速かつ網羅的な細菌管理 (2017)
  • Author(s): 春日郁朗
  • Organizer: 東京大学水環境制御研究センター（RECWET）ワークショップ
  • Invited