"A study was conducted to evaluate the effects of alternative disinfectants on drinking water quality at Jefferson Parish, Louisiana, and the ability of granular activated carbon (GAC) to remove disinfection byproducts and specific organic compounds. Bacteriological information was collected on the influent and effluent of sand and GAC columns. Four parallel pilot-column process streams were dosed with a different disinfectant (ozone, chlorine dioxide, monochloramine, and chlorine) and compared with a fifth pilot-column stream that was not disinfected. After 30 minutes of disinfectant contact time, the water in each process stream was passed through parallel sand, GAC, and duplicate GAC filters, each with 20 minutes of empty bed contact time (EBCT). Samples collected from each process stream were analyzed for total organic carbon (TOC), total organic halide (TOX), 10 volatile organics, 65 solvent- extractable hydrocarbons, 26 chlorinated hydrocarbon insecticides, heterotrophic plate count (HPC), total coliforms, and dissolved oxygen. To simulate distribution conditions, aliquots of each column effluent were dosed with monochloramine and free chlorine and analyzed for TOX and 10 volatile organics after storage for 5 days at river water temperature. The process train that yielded the least dissolved organic contaminants was predisinfection with ozone followed by GAC filtration and post-disinfection with monochloramine."