CHICAGO, Il. — Chriso Petropoulou, PhD, PE, BCEE, Keith Tolson, PhD, and Mary DeFlaun, PhD, co-authored the article "Dry and Wet Weather Microbial Characterization of the Chicago Area Waterway," which is scheduled to be published in an upcoming issue of Water Science and Technology. Other co-authors include Charles Gerba of the University of Arizona as well as Geeta Rijal, Richard Gore, Tony Glymph, Thomas Granato, Catherine O'Connor, Louis Kollias, and Richard Lanyon of the Metropolitan Water Reclamation District of Greater Chicago.
The article details a study, which is the first microbiological characterization of the CAWS for fecal indicators and pathogens, conducted in order to provide scientific information needed to help understand the public health uncertainties in the Chicago Area Waterway System (CAWS). CAWS is a man-made channel serving the Chicago area for the drainage of urban storm water and the transport of secondary treated sewage from the Metropolitan Water Reclamation District of Greater Chicago's (District) North Side, Stickney, and Calumet water reclamation plants (WRPs).
The authors had two major objectives: 1) evaluate the impact of the secondary treated sewage from the District's three major WRPs on the waterway system's microbial quality; and 2) investigate the impact of combined sewer overflows (CSOs) on the on the waterway system's microbial quality.
The study revealed that the concentrations of pathogens in the CAWS, representing the weather conditions experienced in a recreational year, were relatively low. Also, the presence of pathogens in the CAWS upstream and downstream of the WRPs were due to secondary loading of the waterway under wet weather conditions from CSOs and other discharges.