Full-scale evaluation of organic matter removal in riverbank filtration in Korea

Since 1998, both small-scale and full-scale riverbank filtration (RBF) has been introduced in South Korea to secure a stable supply of water. From 2015, a full- scale RBF plant has been in operation with a collector well capacity of 44,900 m(3)/d, which is the largest in South Korea and one of the largest RBF facilities in the world. From the analysis, 58%similar to 59% of the natural organic matter ( NOM) was removed from the river water through the RBF process and the hydrophobic organic carbon content was increased from 3%-5% to 11%-17%. Aromatic compounds, building blocks, and neutral components with a molecular weight of 350-1,000 g/mol were not removed as efficiently as those with lower molecular weight. Therefore, if there is a high content of those components, the removal rate of NOM during the RBF process could decrease. There was not a significant difference in NOM removal in the laterals to depth. The results of this study are in accordance with previous research. The removal of NOM generally occurs during the first several meters on the boundary of the river/aquifer. The total organic carbon (TOC) concentration in the filtrated water fluctuates with the TOC in the river water. This resource is judged to be "groundwater under the direct influence of surface water", and additional water treatment is mandatory after RBF to ensure the safety for potable use.