Abstract: Organic contaminants are removed from waste water streams by initially pretreating the stream to remove suspended solids and oil therefrom and thereafter passing the pretreated waste water through bed(s) of activated carbon while adding a controlled amount of oxygen to the bed(s) in an amount ranging from about 0.05 to about 0.15 pound of oxygen consumed per pound of total COD contaminants removed from the waste water by this process. By following the method of the present invention, the balance between the aerobic/anaerobic biological oxidation of the contaminants adsorbed on the activated carbon may be controlled so as to suppress the evolution of hydrogen sulfide from the bed while minimizing the formation of aerobic biological sludge which would plug the bed(s). This controlled biological activity that occurs in the carbon adsorption system provides for a substantial increase in the effective organic contaminant removal capacity of the activated carbon.