Yellow acid dye was adsorbed from aqueous solution by granular activated carbon packed in a column. The feed concentration was kept constant for a period of time and then switched to another level to simulate the concentration variation in wastewater treatment processes. The resulting breakthrough curves were experimentally measured and theoretically predicted. Explicit equations and an algorithm were developed based on the wave interference theory to predict the column breakthrough curves of single-component adsorption processes with step change in the feed concentration. The experimental results show that the wave interference theory predicts the column breakthrough curves satisfactorily.