An investigation was conducted, as part of model studies utilizing a swirl concentrator as a primary separator, helical combined sewer overflow regulator, and related studies, to characterize the properties of solids in sanitary sewage, combined sewer overflows, and stormwater runoff. To effectuate this study, material suitable for monitoring removal efficiencies in hydraulic models of the swirl concentrator unit has been developed. The approach taken in the simulation sewage studies, was to match as closely as possible the settling characteristics of solids in three types of sewage and/or urban runoff with a well-defined, uniform artificial test material. Importantly, as background information for the selection of synthesized solids, the settling characteristics (including size and specific gravity distribution) of sanitary sewage, combined sewer overflow and stormwater were determined. These values will be useful for future determinations of physical treatment process design and associated treatability.

Report prepared by Beak Consultants Limited, Rexdale, Ontario, Canada. "Contract no. 68-03-0272; Program element no. 1BB034." Includes bibliographical references (pages 27-28).