SELF-CLEANING CONSOLIDATION CONDUIT IS OPTIMIZED BY SCADA CONTROLLED FLUSHING CHAMBERS FOR AUGUSTA, MAINE'S LARGEST COMBINED SEWER OVERFLOWS (CSOs) TO WWTF

The Augusta Sanitary District is implementing the second of its four-phase Long-Term Control Plan for the abatement of its combined sewer overflow discharges. The current program focuses on the West Subsystem with the key component being the West Side Consolidation Conduit (WSCC). Numerous challenges were encountered during the design including: narrow project corridor; active railroad; steep and unstable banks; and coordination with a rails-to-trail project. Additionally, instrumentation and SCADA needed to be designed to control outlet flows from the WSCC to the WWTF, so that the transport conduit acted in a storage mode during high rate wet-weather events. Complicating this control need, the instrumentation also needed to monitor and regulate a storm flow connection to the WSCC, but only for “first-flush”, so that other CSOs being intercepted would not be hydraulically exempted from being captured. These, and other project objective and design considerations, are detailed in the paper.