Simulation of DOC Removal in Activated Carbon Beds

The removal of dissolved organic carbon (DOC) by granular activated carbon (GAC) in a fixed‐bed adsorber was simulated using an approximate analytical solution and was found to agree satisfactorily with the performance observed at a full‐scale plant. Laboratory equilibrium isotherm studies were conducted to estimate the partition parameter and the nonadsorbable fraction of the organic matter. A modified linear isotherm model was found to fit the data acceptably. External and internal mass transfer parameters were based upon general correlations that have been widely applied in fixed‐bed modeling. A mass transfer model based upon the assumption of pore diffusion was utilized to describe the intraparticle transport. An estimation of the biodegradable fraction of DOC was based upon numerous case studies of the application of GAC for water and wastewater treatment. The applicability of this approach was confirmed with operating data from three full‐scale GAC adsorbers. The apparent diffusivities, both predicted and estimated from breakthrough data, were in the range of $6\times {10}^{-11}$ to $14\times {10}^{-11}\text{.}$