St. Charles Pumping Station 3B

Key Accomplishments

• Johnston Construction Company’s scope included site work, excavation support, dewatering, structural concrete, driven H-pile-supported construction, pumping equipment, process piping, force main work, valves, chemical feed equipment, odor control, generator facility, fuel oil system, HVAC, plumbing, instrumentation, controls, electrical service, emergency power, automatic transfer switch, and system startup.
• The project required coordination with Charles County Department of Utilities to maintain operation of existing Pumping Station 3A, divert flow from existing pump stations, pig new force mains, decommission existing Pumping Stations 2, 2A, and 3, and shut down Pumping Station 3A as part of the new station startup sequence.
• Johnston Construction Company performed the work in challenging subsurface conditions that included deep excavation, groundwater, sensitive high-plasticity clay, reinforced mat foundation construction, structural floor slab and pile-supported pipe gallery work, and extensive coordination of buried utilities and existing wastewater infrastructure.
• The project also included a chemical feed and odor control system. Johnston Construction Company installed the Bioxide chemical feed system with chemical storage tanks, chemical feed controls, pumps, leak detection, spill basin, and associated piping and appurtenances. The odor control system included a carbon adsorber package with pressure blower, flow control dampers, carbon vessel, activated carbon media, controls, electrical disconnect, pressure gauge, ductwork, startup, and performance testing.
• The project was completed in accordance with the contract requirements, including startup, testing, owner training, O&M manuals, as-built drawings, permit closeout, warranties, and final restoration.
• The Project Was Completed On 31st December,2017