Optimizing Ozone-Biofiltration Systems for Organic Carbon Removal in Potable Reuse Applications

This study presents a framework for simultaneously evaluating ozone dose and empty bed contact time in ozone-biofiltration systems when aiming to optimize or maximize total organic carbon (TOC) removal in potable reuse applications. Ozone:TOC ratios of 0.35, 0.62, and 1.12 resulted in ΔTOC_max values of 17–19%, 21–24%, and 26–30%, respectively, during pilot scale biofiltration with anthracite or biological activated carbon. The corresponding first-order rate constant for the biodegradation of TOC was similar for both media types (0.25 ± 0.06 min⁻¹). In addition to bulk organic transformation, ozone was effective in reducing the concentrations of many trace organic compounds.