A major public works is being undertaken by the city of Colorado Springs, Color., to implement a new sludge management system. An important element of this system involves the transportation of unstabilized or raw sludges produced at the existing wastewater treatment facility (WWTF) to a solids processing and disposal site located outside the metropolitan area. A 29-km (18-mile) pipeline will be used to transport a blend of primary and secondary sludge to a processing system comprised of anaerobic digestion, facultative sludge lagoons, and final disposal by subsurface injection. A sludge-pumping pilot study was conducted in the summer of 1980 at the Colorado Springs WWTF to obtain data for the design of the sludge pipeline.