Biomedical analyses of roof-harvested rainwater in household storage tanks for efficient use of water resources in Azumino area

2014 Fiscal Year Final Research Report

• Project/Area Number: 24651024
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental impact assessment/Environmental policy
• Research Institution: Shinshu University
• Principal Investigator: OANA Kozue 信州大学, 学術研究院保健学系, 助教 (60115334)
• Co-Investigator(Kenkyū-buntansha): KAWAKAMI Yoshiyuki 信州大学, 医学部, 特任教授 (90283275)
• Research Collaborator: KOBAYASHI Michiko 信州大学, 大学院医学系研究科保健学専攻 ; YAMAKI Dai 株式会社信州セラミックス, 研究員
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 雨水貯留水 / 細菌汚染制御 / アースプラス

Outline of Final Research Achievements

Water samples were collected periodically from 43 household rainwater tanks in Azumino, and tested for the presence of Legionella, coliforms and for the extent of heterotrophic bacteria. Only one sample yielded positive culture for Legionella during the investigation periods. In contrast, PCR assays gave positive results against each 12 samples in June and August, and 17 in October.
The ceramic micro-beads coated with “Earth-plus” were proved to have bactericidal activities against Legionella, coliforms and heterotrophic bacteria. Immerging the ceramic micro-beads in the tanks yielded the favorable eradication of Legionella. Not only rapid-acting but also long-lasting bactericidal activities of the ceramic micro-bead were exhibited against L. pneumophila. However, time-dependent attenuation of the bactericidal activities were noted in the sustainability appraisal experiment. More reliable methods are needed for bacterial contamination measures in rainwater storage tanks.

Free Research Field

臨床微生物