Eleven commercial and experimental powdered activated carbons were subjected to an intensive laboratory evaluation of their physical and adsorptive properties to select those best suited to treating municipal waste water and to gain insight into properties important for this application. Correlations were made between capacities for absorbing organic impurities from municipal secondary effluent, as measured by TOC (Total Organic Carbon) adsorptive capacities, and carbon properties such as iodine value, molasses decolorizing index and pore structure. It is suggested that the best carbon for adsorbing organics from municipal wastes have a broad spectrum of pore sizes. Particle size of the powdered carbons was found to strongly affect the rate of adsorption. Aqua Nuchar, Hydrodarco, and pulverized Nuchar WV-L are recommended for further study. (WRSIC abstract)