AWWA ACE94127

GAC adsorption can be an effective process for removing natural organic matter and controlling the formation of disinfection byproducts. The effectiveness is related to NOM characteristics and pretreatment. The NOM initial concentration has a major impact with higher values leading to much earlier breakthrough. The operation time or number of bed volumes to 50% TOC breakthrough were inversely correlated. Lower pH values associated with enhanced coagulation were found to yield an extension of the GAC life. The lowest and highest molecular size fractions were not well removed by GAC, but the intermediate MS fractions displayed long-term removal. The hydrophobic or humic fraction as separated by the XAD-8 resin was very well removed by the GAC column. Combining measured equilibrium data with the PFPSDM allowed the simulation of DOC breakthrough and the best fit conditions indicated that pore diffusion dominated internal mass transfer. TOC was found to be a good predictor of the breakthrough behavior of TTHMFP.