A procedure was developed to predict the removal of trace organic comp
ounds from natural water by powdered activated carbon (PAC) adsorption
systems, which function as a batch reactor or a continuous stirred ta
nk reactor (CSTR). The procedure uses the equivalent background compou
nd method coupled with the ideal adsorbed solution theory to quantify
the competition between trace organics and background organic matter i
n water, and uses the pseudo single-solute homogeneous surface diffusi
on model to describe the adsorption kinetics of the target compound un
der the influence of the background organic matter. The parameters req
uired by the model as input data can be independently determined from
adsorption isotherms and a set of batch kinetic test data. Good agreem
ent between predicted and actual performance was found for adsorption
of atrazine from Central Illinois ground water at different initial co
ncentrations and different carbon doses using a batch reactor and two
CSTRs, one of which was a PAC/ultrafiltration system.