AWWA WQTC56997

A mathematical model was developed to simulate powdered activated carbon (PAC) adsorption of trace organic compounds from natural water in a floc blanket reactor (FBR). The displacement effect of competing natural organic matter (NOM) on trace organic compound adsorption was taken into account by using an adsorption capacity of the trace organic compound that decreases with time. The model was verified with atrazine adsorption data obtained in a pilot-scale FBR using parameters determined from bench-scale experiments. Two types of PAC with different pore size distributions were tested. Model simulations were conducted to demonstrate the effects of the PAC type, the PAC dose, the carbon retention time (CRT), and the reactor size. Model simulations were performed to determine optimal ranges of PAC doses and CRTs for both types of PACs. The performance of the two PACs was also evaluated to provide adsorbent selection guidelines for water utilities. Includes 14 references, tables, figures.