Evaluation of Enhanced Ozone–Biologically Active Filtration Treatment for the Removal of 1,4-Dioxane and Disinfection Byproduct Precursors from Wastewater Effluent

Ozonation followed by biologically active filtration (BAF) (O3–BAF) treatment has become an alternative to reverse osmosis in potable wastewater reuse applications because of the ability to produce a high-quality effluent while reducing brine production and disposal. In this study, effluent from a sequencing batch membrane bioreactor (SBMBR) was treated by O3–BAF at three specific ozone doses (0.5, 0.7, and 1.0 mg O3/mg DOC) and different empty bed contact times (EBCTs; 15–45 min). The reaction of O3 with granular activated carbon (GAC) (O3/GAC) to promote the formation of hydroxyl radicals (·OH) was evaluated at 1.0 mg O3/mg DOC followed by BAF at 15–45 min EBCT. The efficacy of these techniques was compared for the removal of O3 refractory 1,4-dioxane and the reduction in the formation of bromate, 35 regulated and unregulated halogenated disinfection byproducts (DBPs), and 8 N-nitrosamines after chloramination. Conventional ozonation (without the presence of GAC during ozonation) removed 6–11% of 1,4-di...