Prof. Kumiko Oguma, Department of Urban Engineering, The University of Tokyo

Research

　　Water holds intrinsic value in both quality and quantity, serving as an indispensable resource for healthy living and sustainable societal activities. To maximize its value sustainably, research focuses on various topics, such as water environment surveys, water treatment technologies, and water supply systems. For example, research on UV-based water treatment ranges from fundamental experiments to large-scale applications, with results achieving technological implementation and earning international recognition. Efforts also address water-related challenges in developing and remote areas through continuous fieldwork on water quality and usage. In addition, decentralized small-scale water systems are being explored as potential engineering solutions to urgent societal challenges, such as population decline, aging populations, and deteriorating infrastructure.

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Grant-in-Aid for Scientific Research（Principal Investigator）

Grant-in-Aid for Scientific Research Database

Research Number Research Content
Research Category :
Grant-in-Aid for Scientific Research (A)
Project Period :
April, 2025 – March, 2030
Research Title :
Evaluation of UV sensitivity of single microbial cell using advanced optical control technology and its application to water treatment
Key Word :
UV treatment, Water treatment, Tailing in dose-response profiles, Optical tweezer
Summary :
This study examines the tailing phenomenon in ultraviolet (UV) water disinfection, where inactivation efficiency declines at high UV fluence. While the cause remains unclear, heterogeneity in microbial UV sensitivity may play a role. Based on this hypothesis, advanced optical technologies will be employed to achieve a high-resolution understanding of UV disinfection, offering practical insights for global water treatment applications.
Final Report :
26289181
Research Category :
Grant-in-Aid for Scientific Research (A)
Project Period :
April, 2020 – March, 2025
Research Title :
Application of UV-LED for decentralized water supply systems and wastewater reclamation processes
Key Word :
UV-LED, Drinking water treatment, Wastewater reclamation, Small-scale water system, Industry-Academia collaboration
Summary :
This study focuses on the application of ultraviolet light-emitting diodes (UV-LEDs) for water treatment, exploring their potential in both drinking water purification and wastewater reuse. For drinking water, considering the growing research on decentralized water treatment systems for communities and households, pilot-scale trials were conducted in three countries—Japan, Thailand, and Nepal—each with distinct societal contexts. These trials aim to advance the implementation and commercialization of small-scale water purification systems. For wastewater reuse, laboratory-scale experiments investigated the inactivation of antibiotic-resistant bacteria and the response of antibiotic resistance genes under UV-LED exposure. The findings have been actively disseminated through academic papers, conferences, books, and media appearances, contributing to knowledge sharing both domestically and internationally.
Final Report :
17H03329
Research Category :
Grant-in-Aid for Scientific Research (A)
Project Period :
April, 2017 – March, 2020
Research Title :
Development and evaluation of water treatment system using ultraviolet light emitting diodes operated by independent power supply
Key Word :
Water treatment, Disinfection, Ultraviolet (UV) radiation, off-grid operation, Decentralized water supply
Summary :
This study revealed the inactivation characteristics of various microorganisms in water, using UV light emitting diodes (UV-LEDs) at different peak emission wavelengths. Moreover, field test projects were conducted both in Japan and abroad, indicating the effectiveness and future challenges of flow-through UV-LED water disinfection modules as a part of decentralized water treatment system. In particular, a solar-powered UV-LED water treatment system was conceptualized, developed and finally field tested in an off-the-grid remote island in the Philippines, implying the high potential of standalone UV-LED water treatment systems, independent of power grid and water supply network, for areas and situations where large-scale centralized water supply systems are not feasible.
Final Report :
https://kaken.nii.ac.jp/en/report/KAKENHI-PROJECT-17H03329/17H03329seika/
26289181
Research Category :
Grant-in-Aid for Scientific Research (B)
Project Period :
April, 2014 – March, 2018
Research Title :
Application of ultraviolet light-emitting diodes to suppress microorganisms in water
Key Word :
Water treatment, Ultraviolet (UV) radiation, Disinfection, UV-LED, LED, Biofilm
Summary :
This study aimed to propose the application of ultraviolet light-emitting diodes (UV-LED) for water disinfection and elucidate the effectiveness and challenges of the technology. UV-LEDs with different peak emissions were applied to various microorganisms to examine the dose-response properties. UV-LED module designed for point-of-use (POU) of water or point-of-entry (POE) to buildings were evaluated by lab-scale experiments and a field test. Furthermore, field survey in Hanoi, Vietnam, was conducted to examine the feasibility and local needs for UV-LED water treatment at household level. This study demonstrated the effectiveness and technical challenges of UV-LED to be applied for water treatment and developed fundamental knowledge base for module development and practical applications.
Final Report :
https://kaken.nii.ac.jp/en/report/KAKENHI-PROJECT-26289181/26289181seika/
24760427
Research Category :
Grant-in-Aid for Young Scientists (B)
Project Period :
April, 2012 – March, 2014
Research Title :
Development of water treatment devices using UV light emitting diodes (UV-LEDs)
Key Word :
Water treatment, Disinfection, Ultraviolet (UV) radiation, UV-LED
Summary :
This study aimed to propose the application of ultraviolet light-emitting diodes (UV-LED) for water disinfection and elucidate the effectiveness and challenges of the technology. UV-LEDs with different peak emissions were applied to various microorganisms to examine the dose-response properties. UV-LED module designed for point-of-use (POU) of water or point-of-entry (POE) to buildings were evaluated by lab-scale experiments and a field test. Furthermore, field survey in Hanoi, Vietnam, was conducted to examine the feasibility and local needs for UV-LED water treatment at household level. This study demonstrated the effectiveness and technical challenges of UV-LED to be applied for water treatment and developed fundamental knowledge base for module development and practical applications.
Final Report :
https://kaken.nii.ac.jp/en/report/KAKENHI-PROJECT-24760427/24760427seika/
21760414
Research Category :
Grant-in-Aid for Young Scientists (B)
Project Period :
April, 2009 – March, 2011
Research Title :
Fate of N-Nitrosodimethylamine(NDMA) in water and evaluation of UV irradiation as a treatment process against NDMA
Key Word :
Water treatment, Ultraviolet (UV) radiation, Disinfection by-products, UV treatment, NDMA, Chlorination
Summary :
NDMA concentration in river water and groundwater in Tokyo was examined to show the range of NDMA concentration in drinking water sources. Ultraviolet light at different wavelengths was irradiated against NDMA solution. The result indicated that decay rate differs at different wavelengths, and that co-existing matters including dissolved organic matter and nitrate deteriorate the decay rate of NDMA. Moreover, UV-irradiated NDMA solutions were subjected to chloramination, resulting in no significant reformation of NDMA. Results of this study indicated that UV irradiation is effective as a treatment process against NDMA.
Final Report :
https://kaken.nii.ac.jp/en/report/KAKENHI-PROJECT-21760414/21760414seika/
16760441
Research Category :
Grant-in-Aid for Young Scientists (B)
Project Period :
April, 2004 – March, 2005
Research Title :
Impacts of UV disinfection on aquatic microbial communities in water environment
Key Word :
UV treatment, Water environment, Residual toxicity, DNA damage, Ecosystem, Photoreactivation, Water treatment, Water and wastewater systems, Bioassay, Waterborne diseases
Summary :
Ultraviolet (UV) disinfection of water is widely regarded as a method that produces no harmful disinfection by-products and leaves no residual effects. Consequently, its implementation in wastewater treatment plants is considered promising, particularly from the perspective of protecting aquatic ecosystems at discharge sites. However, some reports have suggested that under certain conditions, UV-treated water exhibits residual effects in suppressing the growth of algae and bacteria.
Given this background, we aimed to determine whether UV disinfection has residual toxicity. Additionally, we sought to quantitatively assess how variations in UV wavelength influence inactivation efficiency, photoreactivation, and dark repair. Our study specifically focused on the growth suppression effects of UV irradiation on algae, conducting experiments and analyses using a pure culture strain of Anabaena variabilis.
The results demonstrated that:
– UV irradiation effectively suppressed the growth of A. variabilis, irrespective of whether a low-pressure or medium-pressure UV lamp was used.
– A. variabilis exhibited a remarkably high ability to repair genetic damage.
– Changes in cell count following UV irradiation could be accurately modeled by assuming both the formation of damage and its subsequent repair.
Final Report :
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16760441/

JST　SICORP EIG CONCERT-Japan

“Smart Water Management for Sustainable Society” within the Strategic International Collaborative Research Program (SICORP) Framework

April, 2020 – March, 2024　”Innovative UV-LED applications to drinking water and wastewater treatment systems for sustainable water management in future communities”

Summary of the joint project Small and decentralized water systems may play key roles to achieve sustainable water management in the future. As an option to enable decentralized water supplies, water treatment systems using UV light-emitting diode (UV-LED) were evaluated in multiple viewpoints. The research strengths of research team include the expertise in field demonstration of UV-LED reactors (U Tokyo, Japan), expertise as a validation center with high international recognition (DVGW-TZW, Germany), and expertise as a research center on environmental toxicology (RECETOX, Czech Republic). To highlight these strengths in an interactive manner, three main tasks were challenged including the validation of UV-LED reactors; field test of the reactors at a drinking water supply and a wastewater reclamation pilot facility; and examination of the fate of PPCPs in UV treatment. With integration of outcomes from these components, this joint research showed some synergies which were not achievable without collaboration. The outcomes were presented and published in multiple occasions, having fruitful feedbacks from academia, industries and practitioners. Project members obtained mutual understanding and trust, which are invaluable for future collaboration. To conclude, this research indicated the effectiveness of UV-LED water treatment as a technical option for small and decentralized water systems.
Final Report https://www.jst.go.jp/inter/report/report_multilateral/report_concert-japan/water/final_oguma.pdf

JST　SICORP JST-NSERC

“Sustainable Water Use” for the Japanese-Canadian Research Cooperative Program, within the framework of the Strategic International Collaborative Research Program (SICORP)

April, 2014 – March, 2018　”Innovative UV Technologies for the Removal of Emerging Contaminants
and Sustainable Water Supplies in Small Communities”

Summary of the joint project The objective of this project was to jointly evaluate and propose the application of novel UV based technologies, i.e. UV-LED and VUV-AOP, for ensuring the safety and sustainability of drinking water supplies in small and rural communities. UV-LED and VUV-AOP were evaluated in a lab-scale in multiple viewpoints while UV-LED was also tested in a pilot-scale in the field. In addition, statistical data analysis and microbial risk assessment were conducted to identify the technical needs in practice at small water systems. The intellectual achievements and expertise were shared between Japan and Canada, and tight networking of water specialists were achieved to seed future research collaborations and enable long term cooperation.
Final Report https://www.jst.go.jp/inter/sicorp/report/canada/final_oguma.pdf

その他

農林水産省受託研究 「昆虫嗅覚受容体を利用した飲食料由来のカビ臭の簡易検査システムの開発（2016年4月～2019年3月、研究分担者 」
厚生労働科学研究費補助金 ・「小規模水供給システムの持続可能な維持管理に関する統合的研究（20LA1005）（2020年4月～2023年3月、研究分担者）
・「小規模水供給システムの安定性及び安全性確保に関する統合的研究（H29-健危-一般-004、2017年4月～2020年3月、研究分担者）
・「地表水を対象とした浄水処理の濁度管理技術を補完する紫外線処理の適用に関する研究（H26-健危-一般-004、2014年4月～2017年3月、研究分担者）
環境省受託研究 ・環境省令和３年度革新的な省CO2 型感染症対策技術等の実用化加速のための実証事業「高効率・長寿命深紫外LED の技術開発と細菌・ウイルス不活化および脱炭素効果の実証（2021年～2026年3月、研究分担者）」
・環境省環境研究総合推進費S-8「温暖化影響評価・適応政策に関する総合的研究（2010年～2015年3月、研究分担者）
・環境研究総合推進費「水系感染微生物による水環境汚染の把握と微生物起源解析の活用に関する研究（2016年4月～2019年3月、研究分担者）」
国内研究助成（抜粋） ・クリタ水・環境科学振興財団2020年度特別助成（2020年～2023年）
・クリタ水・環境科学振興財団「紫外発光ダイオードを利用した小型浄水装置の開発と性能評価（2013年10月～2014年9月）
・下水道振興基金　東日本大震災復興研究等助成「被災時に有効な簡易下水処理技術としての紫外線消毒の検討（2013年）」
自治体・民間との共同研究（抜粋） 「紫外線発光ダイオードを用いた微生物不活化の評価と水処理装置の開発」
「深紫外LEDの水消毒応用に関する研究」
「深紫外発光ダイオードを利用した水処理技術の開発」
「UV-LEDを用いた血液製剤微生物低減化方法の開発」
「水道原水中有機物の紫外線処理に関する研究」

Research

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【 所属 / Affiliation 】

小熊久美子, 博士（工学）
東京大学 大学院工学系研究科 都市工学専攻 教授
東京大学大学院工学系研究科長特別補佐

Kumiko Oguma, Ph.D.
Professor
Department of Urban Engineering, The University of Tokyo
Assistant Dean
School of Engineering, The University of Tokyo

Email: oguma[at]env.t.u-tokyo.ac.jp