Nanofiltration can play an important role in gray water reclamation, but for that, membrane integrity is crucial to water’s safety. Sam Rutten et al. evaluated chemical and new microbial indicators as integrity-monitoring methods for hollow fiber nanofiltration. Normally, the membranes effectively retain divalent ions and organic matter, and nearly all E.coli. Changed behavior can offer valuable insight into the state of the filters.
They found that a broken fiber in a pilot-scale module reduced organic matter and microorganism removal substantially, while flux and ion rejection remained similar. Microorganisms could be employed as indicators in integrity-monitoring methods in large-scale applications, while UV254nm absorbance, mostly from organic matter, could be a viable solution in pilot-scale gray-water systems.
Rutten, S.B., B.L. Ojobe, L. Hernández Leal, J. de Grooth, H.D.W. Roesink, J. Bartáček, H. Schmitt. 2023. “Evaluation of Membrane Integrity Monitoring Methods for Hollow Fiber Nanofiltration Membranes: Applicability in Gray Water Reclamation Systems.” ACS ES&T Water, November. https://doi.org/10.1021/acsestwater.3c00307