AWWA ACE65177

Recently, a series of practical models was developed that can be used to predict total organic carbon (TOC) breakthrough in granular activated carbon (GAC) absorbers. These models have been successfully applied in a variety of unique situations that may be of interest to researchers, consultants, and others within the drinking water treatment community. The specific objectives of this presentation are to: demonstrate the practical applicability of the TOC breakthrough models; and, increase the general awareness of models within the drinking water community. A brief discussion of model development and validation details is provided, but the focus of this work is on model application and presentation of case studies that demonstrate the usefulness and importance of the models. Data used for model development was extracted from the U.S. Environmental Protection Agency's (USEPA's) Information Collection Rule (ICR) database. It included 221 individual small-scale breakthrough tests performed using 35 different water sources. Two types of models were developed. One predicts throughput to a given breakthrough percentage (20, 30, ...70%). The other predicts throughput to a given threshold concentration (1.0, 1.5, or 2.0 mg/L). Models were developed for two bituminous GAC field-scale sizes, 12x40 mesh and 8x30 mesh, and two empty bed contact times, 10 and 20 minutes. The only model inputs are values for influent TOC concentration (TOC₀) and pH. External validation was performed using both small- and field-scale data. The presentation presents objectives, approach, and results for three applications that include: sensitivity analysis; GAC use rate estimation; and, optimization tool. Includes 3 references, tables, figures.