Reduction characteristics of disinfection by-product (DBPs) generated by allogenic organic matter (AOM) using micro-hollow beads in terms of particulate removal

Allogenic organic matter (AOM) removal technologies using micro-hollow beads have been developed. Micro-hollow beads with low density (0.125 g/cm3) were found to be effective for the flotation in terms of particulate matter removal. To investigate the characteristics of AOM, extracellular organic matter (EOM), and intracellular organic matter (IOM) before and after chlorine injection, the effect of molecular weight distribution on liquid chromatography with organic carbon detection was examined. The chromatography dissolved organic carbon values of EOM and IOM were 7.5 and 1.6 mg/L, respectively, and the compositions of building blocks and humic substances of EOM and IOM were 58% and 20%, respectively. A particle counter was used to confirm the reduction in the number of residual particles by micro-hollow beads. The concentration of particulate matter decreased with a higher concentration of micro-hollow bead injection due to the attachment and flotation of micro-hollow beads to particulate matter. By removing precursors of the disinfection by-products (DBPs), micro-hollow beads were able to reduce the concentration of DBPs and DBPFP. Haloacetic acids (HAAs) were converted to particulate material through a chlorination process rather than through trihalomethanes (THM) and are efficiently removed by the micro-hollow beads. Compared with THMs/total organic carbon (TOC), HAAs/TOC showed better removal characteristics. THMFP concentrations remained constant over time, whereas HAAFP and HANFP values increased with retention time. Over 7 d of reaction, THMFP and HANFP showed no change in constituents, but HANFP was detected as TCAN, DCAN, and DBAN.