Granular Activated Carbon Adsorption of Dissolved Organic Matter and Trace Organic Contaminants: Effects of Influent Dissolved Organic Matter Concentration and Pretreatment

Granular activated carbon (GAC) adsorption is an effective technology for the control of disinfection byproducts (DBPs) and the removal of trace organic contaminants. While the GAC adsorption of dissolved organic matter (DOM) as a DBP precursor has been extensively investigated and is quantitatively understood, the effectiveness of the GAC adsorption of trace organic contaminants is not. Additionally, the impact of influent DOM, measured as dissolved organic carbon (DOC) concentration, and pretreatment processes like ozonation and ion exchange, on the performance of GAC adsorbers has not been comprehensively evaluated. The objective of this thesis was to evaluate the performance of GAC adsorbers for the removal of DOC and DBP control as well as trace organic contaminant removal for waters pretreated by ozonation/bio-filtration that varied in influent DOC concentrations, and for waters pretreated by the magnetic ion exchange (MIEX®)process and ozonation/bio-filtration, relative to conventional treatment. A series of rapid small-scale column tests (RSSCTs) were performed to evaluate the performance of the GAC. Results indicate that, on a normalized basis, an inversely proportional relationship between throughput to a target effluent DOC concentration and the influent DOC concentration does not exist for waters that have been pretreated by ozonation/bio-filtration. In terms of pretreatment, ozonation/bio-filtration decreased the adsorbability of the DOC while MIEX® increased adsorbability, yielding delayed DOC breakthrough, relative to conventional treatment. The DBP formation was found to be linearly correlated to the DOC concentration after GAC adsorption, and little difference was found in the DBPs reactivities of the different pretreated waters after GAC adsorption. For the trace organic contaminant adsorption, systematically earlier breakthrough was observed as the influent DOC concentration increased, and the MIEX® pretreatment decreased the adsorbability of the contaminants, relative to both conventional treatment and ozonation/bio-filtration pretreatment.