CSO Control, Treatment and Disinfection at Saco Wastewater Treatment Plant using Advanced Vortex Technologies

The use of novel CSO control, treatment and disinfection systems based on advanced vortex technologies including Vortex Flow Controls (VFC) and Hydrodynamic Vortex Separator (HDVS) that enable, Screening, Grit Removal, Sedimentation and Disinfection to be accomplished in one vessel is described. The application of the technologies at the Saco Wastewater Treatment Plant involves a new generation of HDVS and vortex flow controls that regulate wet-weather flows to control maximum flows to the existing wastewater treatment plant to avoid hydraulic overloading and the diversion of excess combined sewage flows to the new CSO treatment facility.The wet-weather treatment facility utilizes an advanced HDVS that incorporates a non-powered, self-activating and self-cleansing CSO floatables screening system; with the captured pollutants comprising sewer debris and solids including sediments, settleable organic solids and floatables, being returned to the headworks at the treatment plant and the clarified, screened and disinfected overflow being discharged to the receiving environment (Saco River), after de-chlorination.The ability to perform several essential unit processes (i.e. Screening, Grit Removal, Sedimentation and Disinfection) all in one vessel resulted in significant savings in the overall project scheme costs on account of the more compact design of the advanced HDVS system coupled with the elimination of additional tanks and vessels that would have been required with the conventional approach. Analytical results from post-construction compliance monitoring have confirmed the efficacy of the advanced vortex technologies.