Bench-scale ozonation for removing constituents of emerging concern

This study assessed the efficiencies of removing constituents of emerging concern (CECs) with ozone and ozone in combination with hydrogen peroxide in a bench-scale flow-through system designed to predict full-scale removals. Five CECs were selected for evaluation: atrazine, caffeine, carbamazepine, primidone, and tris (2-chloroethyl) phosphate. Two modeling compounds, 2-methylisoborneol and geosmin, were used to establish benchscale operating conditions that mimicked previous pilot- and demonstration-scale removals. The study demonstrated that CEC removal efficiencies in bench-scale systems are generally consistent with removals in full-scale systems. Thus, the bench-scale system can be used to predict full-scale removals. Additionally, bench-scale results showed that CEC removal efficiencies were generally higher in State Project water (SPW) than in Colorado River water (CRW) or the SPW/CRW blend. These results were likely a consequence of the rapid formation of hydroxyl radicals in SPW.