WRRCTR No.166 Activated Carbon Adsorption of Low Concentration Organic Pesticides in Water

Abstract

A series of thirty separate experimental laboratory benchscale runs were conducted in which concentrations of EDB and DBCP in water, ranging from 2,170 to 10,000 parts per trillion (ppt), were treated by passing various quantities through both standard and fine-grained Calgon and Darco granulated activated carbon (GAC). The results of the experiments indicate that Calgon is more efficient than Darco in removing EDB and DBCP, that fine-grained GACs are more efficient than standard GACs, that EDB is removed more efficiently than DBCP, and that when a mixture of EDB and DBCP is passed through the same GAC, the pesticide removal efficiency of the GAC -- based on fine-grained Calgon -- decreases significantly. At single concentrations of EDB, no detectable concentrations (at the 10-ppt level) were noted when the maximum flow-through GAC loading rates were 259 gal/lb•day (1.50 ml/g•min). Based on extrapolated results, the GAC requirement for 100 ppt pesticide concentrations is estimated to be approximately 1.0 lb/1.0 mil gal.