Hydraulic fractionation of conventional water quality constituents in municipal dry- and wet-weather flow samples

Abstract

The effective design of treatment processes for combined sewer overflows (CSOs) requires understanding of the CSO characteristics and treatability. Environment Canada partnered with four municipalities to evaluate water quality and treatability of wet- and dry-weather flows at local sewage or CSO treatment facilities. Chemical characterization of the samples indicates that the municipal sewage at all of the sites is of relatively weak strength, with several differences between the water quality data for dry-weather and wet-weather flows (assumed to represent CSOs). Hydraulic separation of constituents with an elutriation apparatus illustrated the removals that can be expected with conventional settling techniques and differences in settling of various constituents.

Assessing Settleability of Dry and Wet Weather Flows in an Urban Area Serviced by Combined Sewers

“…This follows from the fact that most of the pollutants of concern are hydrophobic, partition preferentially with solids, and can be therefore removed with fine solids (Ashley et al 2003;Exall et al 2009). …”