Evaluation of granular activated carbon for removal of trace organic compounds in drinking water

Abstract

Drinking water supply from Feng Yuan waterworks was studied by bench-scale experiments examining effects of different particle size of granular activated carbon (GAC), pH, dosage, and temperature, and by forming the Freundlich adsorption model. The adsorption performance could be significantly improved by using small-size GAC, low pH, low temperature, and an increase in the dosage of GAC. The use of the Freundlich adsorption, model had the potential in evaluating the behavior of GAC. The results reflected the better adsorption efficiency of GAC in the higher initial concentration of total organic carbon (TOC) from the drinking water source. In addition, the adsorption capability (q e) and the Freundlich constant (n) increased with increasing operation time. In a single column study, a low flow rate led to an increase in adsorption capacity and breakthrough time and a decrease in the treated water volumes. In the next step, the bed depth/service time or BDST design method was used to predict the breakthrough profiles for TOC in the four serial columns. The column service time and treated water volumes were all reduced while high adsorption efficiency of GAC could be achieved. Furthermore, the operation at a low flow rate improved the adsorption capacity (N o) of GAC for the same TOC removal percentages.