AWWA ACE58132

The City of Tempe, Arizona is planning to expand their Johnny G. Martinez Water Treatment Plant (JGMWTP) from an existing capacity of 50 mgd to 80 mgd. As part of this expansion, process upgrades are also being considered to improve finished water quality. Key water quality goals to be addressed in this upgrade/expansion are the removal of chlorinated disinfection byproduct (DBP) precursors, better control of taste and odor, and increased pathogen inactivation. Existing processes at JGMWTP include conventional treatment with anthracite/sand filters and powdered activated carbon to control T&O and also to remove organic carbon. A pilot study was conducted to evaluate granular activated carbon (GAC) as a potential replacement of the existing anthracite media. Goals of this study included evaluating the production and water quality performance of the GAC filters, and to evaluate DBP precursor and taste and odor (T&O) control. Based on the results of this study, GAC filtration media was recommended for the expanded JGMWTP. Includes table, figures.