A 15,000 gpd pilot plant was constructed to demonstrate the capabilities of a lime treatment process for phosphorus removal. The lime treatment of raw wastewater removes the bulk of the phosphorus, and a subsequent biological process removes an additional increment of phosphorus via cell synthesis. The pilot plant used for the study was a package-type, prefabricated unit. Additional small tanks were provided for sludge storage and measurement. A variable speed motor was mated to a program controller to duplicate a diurnal flow pattern through the pilot plant. Lime was introduced into the raw wastewater in response to an automated pH control system. Instrumented systems were also developed for turbidity and ortho-phosphate concentrations in the plant effluent. The raw wastewater entering the pilot plant was obtained from the wet well of the Manhattan, Kansas Municipal Plant. (Modified author abstract)