The report is a supplement to the report, 'The Swirl Concentrator as a Combined Sewer Overflow Regulator Facility' (PB-214 687). The work described by this report allows flexibility for the designer faced with structural, head or land area constraints by enabling interchange of basic heights and diameter dimensions. The 1972 studies established a suitable relationship between swirl chamber depth and diameter and their effect on the liquid flowfield and particle removal efficiencies. This report presents an account of supplemental studies of a hydraulic model of the swirl concentrator. The report translates the model study findings into a design basis that can be used for any rational flow rate in universal service for the treatment of combined sewer flows. It establishes the basic principle that variations in overflow weir height, or chamber depth, do not materially influence solids particle removals and that the most definitive design parameters are size of inlet sewer and swirl chamber diameter. It also provides design curves for various influent flow rates, covering chamber diameters and inlet sewer sizes which will produce settleable solids removal efficiencies of 70, 80 and 90 percent. It presents design details for flotable solids traps to retain these components, and for essential details of swirl chamber geometrics. Procedures are outlined on how the model study curves can be used in the design of prototype swirl concentrator units of various capacities and dimensional relationships.

"Contract no. 68-03-0283; Program element no. 1BB034." "A supplement to the Swirl concentrator as a combined sewer overflow facility, EPA-R2-72-008, September 1972." "July 1974." Report prepared by American Public Works Association, Alexander Potter & Associates, and LaSalle Hydraulic Laboratory, Ltd.