Mathematical models application for natural organic matter adsorption onto activated carbon

Abstract

Natural organic matter (NOM) normally exists in raw surface water as a complex mixture of organic compounds, mainly humic acids and fulvic acids. In water treatment plants, free chlorine reacts with NOM and forms a wide range of substances known as disinfection byproducts (DBPs). Granular activated carbon (GAC) adsorption is one of the best available technologies employed for the removal of NOM. Mathematical models for the adsorption of NOM onto GAC in a fixed bed column were reviewed. These models were solved numerically using finite element and orthogonal collocation methods. Of all the tested models, best agreement was obtained between predicted values using homogenous surface diffusion model (HSDM), incorporating adjustment of the average particle size with a proper value of sphericity factor, and experimental results conducted using rapid small scale column tests (RSSCT) for a range of empty bed contact times (EBCT), GAC particle size, and raw water pH. Most of the model parameters were determined ex...