The primary objectives of this research were: To demonstrate zero order removals of several simple organic compounds alone and in a mixture by a mixed population activated sludge; to observe the removal rates of these organics in terms of the laboratory and field parameters in use today; to show that the summation of the COD removals of each of the compounds alone, results in the overall COD removal of a treatment unit containing a mixture of the organics in the same initial concentrations; and, to observe the removal of these simple compounds by two types of microbial population, filamentous and flocculent.