In September 2016, the torrential rains of Tropical Storm Hermine coincided with catastrophic failure of the City’s Marshall Street APCF Influent Pump Station. The below-grade dry pit station along with its electrical and pumping system was rendered inoperable. Within hours, McKim & Creed was on site to help, offering options for the City’s consideration and coordinating a solution.
Due to this catastrophic failure, McKim & Creed was tasked with performing a condition assessment of all equipment located within the existing headworks facility. This included evaluation and replacement of the influent wetwell structure, grit removal, screening, I&C, electrical, pumps, and odor control. This assessment, design and construction had to be completed within 14 months. As part of this project, McKim & Creed also assisted the City with obtaining FEMA funds for these repairs.
The repair option selected included installing a temporary bypass system and rehabilitating the existing pump station. McKim & Creed designed the repairs in the form of a dry pit submersible configuration for a 30 mgd capacity. The rehabilitation included development of updated flow projections and pumping capacity criteria; replacement of damaged extended shaft vertical centrifugal pumps with dry pit mounted submersible pumps; redesign of discharge piping, and existing electrical gear and motor controls; repairs to existing bar screen system; replacement of gates in grit channels and splitter box areas; upgrade of ventilation in dry pit area; and miscellaneous yard piping, conduit and structural repairs.
The temporary bypass system was designed for a peak flow of 30 mgd and included a redundant bypass pumping configuration with a 50,000-gallon tank, temporary bar screen system, and temporary electrical and control systems to operate for the duration of the pump station rehabilitation.