Combination of Ozone with Activated Carbon as an Alternative to Conventional Advanced Oxidation Processes

The objective of this study was to compare the efficiency of O3/granular activated carbon (GAC) to enhance ozone transformation into OH radicals, with the common advanced oxidation processes (O3/OH , O3/H2O2). The results obtained with model systems under the given experimental conditions showed that the system O3/OH (pH 9) and O3/H2O2 (pH 7, [H2O2] = 1 10 -5 M) are more efficient than O3/GAC (pH 7, [GAC] = 0.5 g/L) to enhance ozone transformation into OH radicals. However, in Lake Zurich water the O3/GAC process has a similar efficiency as O3/H2O2 for ozone transformation into OH radicals. The results also show that the presence of GAC during Lake Zurich water ozonation leads to (i) removal of hydrophilic and hydrophobic micropollutants, (ii) reduction of the concentration of CO3 /HCO3 , and (iii) decrease of the concentration of dissolved organic carbon (DOC) present in the system.