Author(s): Som Dutta; Talia E. Tokyay; Yovanni A. Cataño-Lopera; Sergio Serafino; Marcelo H. Garcia
Keywords: CFD; grit chamber; sediment transport; two-phase flow; water reclamation plant
Abstract: The Terrence J. O'Brien Water Reclamation Plant (WRP) serves a population of around 1.3 million people and service area of 368.8 km2 in Chicago, IL. Metropolitan Water Reclamation District of Greater Chicago, the agency responsible for the maintenance and operation of the WRP, observed non-uniform distribution of grit deposition between the six grit tanks. Single- and multiphase flow simulations were used to investigate the non-uniform grit distribution and to evaluate potential solution alternatives to ensure the plant operates at an optimal capacity. The simulations revealed the formation of secondary currents due to a bend in the approach conduit; this explained the preferential sediment conveyance along the left side of the conduit and higher deposition at the southernmost grit tanks. Baffles at the centre of the approach conduit and a constriction wall along the left side were recommended for breaking the secondary currents and uniform distribution of the grits.