Efficiency evaluation of an installed swirl separator

Abstract

Municipalities try to limit overflow of their sewer systems by various technologies such as storage in basins and transfer of the water after the storm to a treatment facility, storage and decantation, on-line treatment of overflows, or by alternative technologies like porous roadways or runoff infiltration. The swirl separator, proposed by the American Public Work Association, is an attractive device, because it requires little supervision and maintenance. However, only few results exist about its efficiency for treating combined sewer overflow. The purpose of the present field study was to determine the performance of an existing device (the Québec swirl regulator). The results, presented herein, show that up to 25% of the suspended solids transported during storms can be eliminated, but most of the liquid–solid separation seems to take place in the upstream collecting pipe. Key words: combined sewers, overflows, water treatment, suspended sediments.