Development of a novel membrane integrity testing method by continuous monitoring using optical fiber sensors.

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04662
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22060:Environmental systems for civil engineering-related
• Research Institution: The University of Tokyo
• Principal Investigator: HASHIMOTO Takashi 東京大学, 先端科学技術研究センター, 講師 (80735712)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 浄水処理 / 膜ろ過 / 異常検知 / 光ファイバセンサ / 数値流体力学 / 確率過程 / 予測モデル / 膜劣化

Outline of Final Research Achievements

A novel membrane integrity-testing method was developed based on monitoring the pressure change inside a membrane module induced by the membrane failure by optical fiber sensor. It was demonstrated that the developed method could detect and identify the location of the membrane failure in a module. The computational fluid dynamics (CFD) analysis and the experimental investigation of a failed hollow fiber membrane revealed that the short-cut flow rate in a failed membrane was overestimated by the conventional method and the filtration flow is not negligible. Furthermore, it was shown that the performance degradation of aged membranes may be caused by the increase in the minimum diameter of the flow path inside the membrane.
A novel method for estimating membrane replacement timing was proposed by applying a stochastic process model to membrane failure data obtained from a membrane filtration plant.

Free Research Field

環境工学

Academic Significance and Societal Importance of the Research Achievements

本研究では、これまでオンラインでの監視が困難とされきた膜ろ過施設稼働中のろ過膜の破断について、光ファイバセンサを応用することで常時監視できる可能性を提示し、また浄水処理分野において光ファイバセンサの応用可能性を示した。また、破断膜における流れ、膜内部の多孔質構造における流れ現象を数値流体力学を用いた解析により明らかにし、中空糸ろ過膜における流動および阻止機構の解明に資する知見を得た。構築したろ過膜の異常検知予測モデルに基づく膜交換時期推定手法を提案し、現場での応用可能性を示した。