Evaluation of organics reduction performance of the GAC filtration with regenerated carbons using the long-term operational data of drinking water treatment facilities

Degradation of raw water quality promoted the introduction of GAC (granular activated carbon) filtration and ozonation into Korean drinking water treatment facilities in 1994 in order to cope with organic pollutants. This study focuses on the evaluation of organics reduction performance of the GAC filtration with regenerated carbons using long-term operational data. Three drinking water treatment facilities at Busan were selected for this purpose. It was found in this study that GAC filtration and ozonation helped these facilities to reduce the treated levels of DOC (dissolve organic carbon) as well as of 1,4-dioxane. Regeneration affected organics reduction performance of GAC filtration. The GAC filtration with regenerated carbons was found more effective for DOC reduction, while the filtration with virgin carbons was more effective for THM (trihalomethane) reduction. These results were related to the pore size change that occurred after the regeneration. The regeneration increased the meso pore volume but decreased the micro pore volume. The regeneration cycle was important for the decrease in the micro pore volume. The micro pore volume remained relatively unchanged after the first regeneration but was substantially decreased after the regeneration was repeated by more than second time.