AWWA WQTC64107

This slide presentation outlines a project where, in 2004, the Regional Municipality of Waterloo (RMOW) shut down its Greenbrook Water Treatment Plant when 1,4-dioxane was found in well supply up to 285 ppb. Associated Engineering was hired to conduct a Treatability Study that included a Literature Review, Bench-Scale Study, and a Pilot-Scale Study. Objectives of the Pilot-Scale Tests included: demonstrate 1,4-dioxane destruction with 3 advanced oxidation processes (AOPs) and their suitability at Greenbrook: UV / H₂O₂; O₃ / H₂O₂; UV / TiO₂; O₃ dosing control (O₃ / H₂O₂ only); monitor bromate formation, if any; confirm improvement with upstream filtration; examine level of Fe / Mn removal through AOP; and, determine H₂O₂ residual for future quenching considerations. Raw water quality considerations and pilot process train are outlined along with the pilot study summary that includes: filtration process confirmed Fe/Mn removal; minimal improvement for downstream AOP; 1,4-Dioxane removal and byproduct formation; and, all AOPs tested were able to meet low target dioxane levels (< 10 µg/L) without forming high levels of bromate.