Development of Bench-Scale Settling Apparatus: Settling Velocity Data for Design and Operation of Wet-Weather Flow Solids-Liquid Separation Processes

Abstract

This study is a side-by-side comparison of a traditional settling-column particle-settling- velocity distribution evaluation method and a new settling evaluation method. This portion of the study investigates whether these column tests are capable of capturing or representing the rapidly settling particles present in wet-weather flows (WWF). Equipment for the two testing methods was fabricated and laboratory tested and preliminary evaluations were made. This interim report reviews the sampling procedures and analytical methods used and presents data and results. Laboratory tests were conducted with well characterized settling media, in order to measure suspended solid (SS) concentrations and develop settling distributions on known substances in the columns prior to testing actual WWF which exhibits variable SS concentrations and settling distributions. The main purpose of this ongoing study is to obtain design data for WWF SS separator treatment devices, e.g., vortex separators, grit chambers and settling tanks. A summary of the performance as measured by predicted percent removal of both columns for 15 laboratory tests is presented, as well as a comparison of the advantages and shortcomings of the two methods.

1999
EPA# EPA/600/X-99/031