GAC ADSORBER DESIGN PROTOCOL FOR THE REMOVAL OF OFF-FLAVORS

This paper investigates the effectiveness of granular activated carbon (GAC) for removing off-flavor compounds of water-geosmin and 2-methyl isoborneol (MIB). More specifically, it focuses on the development of an appropriate modeling approach and experimental protocol for the des ign of fixed-bed GAC adsorbers. Adsorption equilibrium, rate and long- term mini-column studies were conducted on a bench-scale for geosmin a nd MIB to estimate the equilibrium and mass-transfer parameters requir ed for adsorber modeling. The dispersed flow homogeneous surface diffu sion model (DFHSDM) was used for the prediction/simulation of the adso rber dynamics. Scale-up procedures based on dimensional analysis and s imilitude were employed for the design of full-scale adsorbers from be nch-scale adsorbers, and for performance forecasting of full-scale ads orbers under different operating conditions. More importantly, operati on and maintenance (O & M) costs were estimated for full-scale adsorbe rs directed at the removal of off-flavor compounds, based on carbon ut ilization rates and disposal costs. These estimates were obtained for different plant capacities and empty bed contact times (EBCTs).