Characterization of GAC/PAC Wastes   There are a number of utilities in the U.S. that use GAC or PAC in some phase of drinking water treatment. It has been shown that activated carbons are very efficient at removing organic contaminants from water. It is likely that the use of this treatment will continue to increase as water quality standards become more stringent and the number of utilities affected by these criteria increases. Those affected include facilities with or without on-site regeneration capability, facilities removing radon with GAC, and those that use PAC for organic reduction. In all of these situations, the resulting PAC or GAC waste could be classified as hazardous if some chemical determined to be hazardous were present in the raw water. This classification has a significant impact on those utilities, particular when they try to dispose of the residual carbon. EE&T was selected by the AWWA Research Foundation to determine what processes could result in residuals being classified as hazardous and how utilities could operate to avoid this situation. In addition, this work will characterize carbon that has been designated as hazardous and develop appropriate disposal options for this material. EE&T is working on this project with the Cincinnati Water Works, South Adams County Water and Sanitation District in Colorado and the City of Fresno, California.