The objective was to develop and evaluate, at full plant scale, the combined chemical-biological process of phosphorus removal. Alum proved to be a more effective precipitant than sodium aluminate in the moderately alkaline wastewater used. Total phosphorus concentration of the unfiltered effluent was dependent upon effluent suspended solids levels as well as on effluent soluble phosphorus concentrations. Removal of organic matter was improved as a result of chemical addition in the chemical-biological process. The chemical-biological process produced approximately twice as much weight of sludge as did the parallel control. Alum addition did not reduce the sludge volume index (SVI) of the mixed liquor whereas sodium aluminate addition resulted in significant decreases. Costs for chemical precipitation of phosphorus in the chemical-biological process are estimated.