Fluidized Bed GAC Filtration for the Control of Ozone Residuals

A laboratory scale study was conducted in order to investigate upflow granular activated carbon (GAC) filtration for the removal of aqueous ozone. The experimental results showed that fluidized bed GAC filtration operated at hydraulic loadings of 60 — 100 m/h is a promising process for the safe destruction of ozone residuals at the end of ozone contactors. The key parameters in terms of ozone destruction are empty bed contact time, the specific ozone destruction capability of the different GACs and the specific surface of the carbon. Ozone removal in such filters was well described with first order kinetics and external mass transfer was not limiting. Under given conditions in terms of ozone influent concentration, GAC granulometry, GAC density and bed depth, hydraulic loading and available headloss have to be traded off in order to design a well adapted and robust system.