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Zimmermann, Karl

University of British Columbia

Natural organic matter in drinking water interferes with disinfection, threatening public health. Measured as dissolved organic carbon (DOC), organics removal is typically needed around 40- 60% of influent concentrations. Biological ion exchange (BIEX) combines the excellent DOC removal of ion exchange (IEX) with the minimal maintenance of biological activated carbon (BAC) filters. This research programme described the mechanisms of DOC removal during the long-term operations of BIEX filters. Water quality analyses of continuous flow columns enabled the description of three mechanisms for DOC removal. During ‘primary IEX’, chloride is released while DOC, sulphate and nitrate are removed. After chloride exhaustion, ‘secondary IEX’ begins where sulphate is released, and DOC and nitrate are removed. ‘Biodegradation’ occurs throughout. Strongly basic anionic (SBA) resins during primary and secondary IEX exhibited 62% and 35% DOC removal, respectively, while weakly basic anionic (WBA) resins exhibited 31% during both primary and secondary IEX; WBA resins are recommended for systems operating in secondary IEX. Next, the contributions of biologically-mediated DOC removal during BIEX was merely 5% and similar to BAC filters, despite differences in microbial community compositions. In another study, the presence of a biofilm decreased DOC removal by 7% but was accompanied by an 8% increase from biologically active resins. These findings suggest that the detriment of a biofilm’s presence is offset by its biological contributions. Understanding these findings, it was concluded that sulphate-based secondary IEX is the most important mechanisms for BIEX performance and should be prioritized over biologically mediated processes in future water system designs. Finally, long term success of drinking water systems requires a water partnership between diverse stakeholders and especially the water users. The final study shares water stories and recommendations from water leaders worldwide towards building collaborative water partnerships. Foremost, a three-step process of Awareness, Education and Resources empowers people to participate in decision-making processes, critical to sustainable access to safe drinking water. This research increased the knowledge of BIEX fundamentals and provided design recommendations. With increased understandings, biological ion exchange filters are well positioned as a tool for safe water provision across Canada and the World.

Text

2025-03-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87547

Chemical and Biological Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/