Granular and powdered activated carbons are receiving increasing attention as a means for removing dissolved BOD and COD from municipal wastewater. Pilot plants utilizing both materials for removing organic materials from secondary effluent are described. Interest is now high in the use of activated carbon as a substitute for the activated sludge process. Indications are that the cost of powdered carbon adsorption processes will be very close to that of granular carbon. Powdered carbon plants will probably entail a smaller initial investment and may have application where the need for carbon is sporadic.