An experimental study of the application of a fluidized sludge blanket clarifier to the coagulation and separation of wastewater solids was made to determine the effects of controlled process variables on the treatment achieved. Experiments using alum and ferric chloride coagulants were carried out in 12- and 24-inch diameter columns by systematic variation of wastewater pH, coagulant dose, upflow fluid velocity, and blanket depth. The results were analyzed using regression analysis techniques and empirical relationships were derived relating the variables to the removal of suspended solids, total organic carbon, phosphorus, and coagulant metal ions. The sludge production rate was also correlated empirically with the operating variables. Both alum and ferric chloride were found to be effective coagulants. The sludge blanket acted as an efficient clarifier up to at least 15 ft/hr superficial velocity, although best removal efficiencies were achieved at lower rates. (Author Modified Abstract)