AWWA WQTC69361

This powerpoint presentation begins by presenting study objectives that include evaluating the following technologies for the removal of taste and odor (T&O) compounds, specifically MIB, using bench scale testing: Powdered Activated Carbon (PAC) Jar Tests; Granular Activated Carbon (GAC) Rapid Small-Scale Column Testing; Ultraviolet Advanced Oxidation Process (UV AOP); and, Ozonation Advanced Oxidation Process (Ozone/H₂O₂). Pac testing matrix produced the following conclusions: calgon WPH carbon performed best; chlorine will reduce PAC performance by at least 10-20%; moving chlorination downstream of PAC application will improve MIB removal downstream of clarification, on top of filters and at clearwell entrance; and, a secondary treatment system is needed to achieve an MIB finished water target level of 5 ng/L. UV AOP testing produced the following conclusions: UV AOP showed over a 99.999% (5 log) reduction in MIB; other water quality parameters were not impacted (TTHM, HAA5, turbidity, alkalinity, and iron); use of UV AOP resulted in a small increase in AOC concentration; UV AOPs need to be located downstream of filtration; and, quenching of peroxide residual is necessary. Ozonation AOP testing produced the following conclusions: AOC levels increase as ozone doses increase, and would require biological filtration using granular media; ozone alone can reduce MIB to very low levels; ozone should be located upstream of filtration in order to remove AOC; and, would expect about 5% improved performance with peroxide. Granular Activated Carbon (GAC) Rapid Small-Scale Column Testing (RSSCT) produced the following conclusions: Calgon F400 performed best; modifying current filters for use as GAC filter adsorbers would not be practical because TOC pre-loading greatly impacts the ability to remove MIB, and at least two change-outs of GAC would be needed per year, with one change-out happening right before T&O season; post-filter contactors, operated seasonally, would provide required taste and odor removal used in combination with PAC, EBCT = 7 min and without PAC, EBCT = 15 min; and, operated for 90 days of the year when taste and odor events are expected to occur. Includes tables, figures.