FEASIBILITY OF CROSS-FLOW MICROFILTRATION FOR COMBINED SEWER OVERFLOWS
Combined sewer overflows contribute high levels of suspended solids, pathogenic microorganisms, oxygen-demanding compounds and other pollutants into the receiving stream [US EPA, 2001]. The level of pollution coupled with regulatory pressure is challenging communities to find feasible treatment alternatives. Microfiltration may be a preferred treatment alternative. The feasibility of cross-flow microfiltration for the treatment of a dilute primary sewage effluent simulating combined sewer overflow wastewater was investigated. Ceramic membranes of various pores sizes (0.05 - 5.0 um) were tested at the bench and field scale to understand the impact of operating conditions on the permeate water quality and flux rate. A 0.2 um membrane operated with a 1.8 m/s cross flow velocity, a transmembrane pressure less than 2.1 bar and a backpulse frequency of 60 seconds were selected as the preferred operating conditions. The 0.2 um membrane consistently met water quality objectives for fecal coliforms, E Coli, enterococci, BOD5 and SS. The steady state flux rates are impacted by the feed suspended solids concentration and temperature, and an understanding of these parameters is critical to commercial scale design.
Advisor:Ronald D. Neufeld; Radisav Vidic; Leonard W. Casson
School:University of Pittsburgh
School Location:USA - Pennsylvania
Source Type:Master's Thesis
Keywords:civil and environmental engineering
Date of Publication:09/03/2003