White Plains Commerce Center Pump Station Upgrade

Key Accomplishments

Johnston Construction Company

• Installed a new duplex submersible non-clog wastewater pumping system designed for approximately 100 GPM at 32 feet of total head. The specified pumps incorporated a minimum 3-inch solids passage, motors not exceeding 3 HP, monitoring for motor temperature and leakage, and lift-out components designed to facilitate inspection and maintenance.
• Constructed a new above-ground valve enclosure and associated wastewater process-mechanical system, incorporating new process piping, check valves, resilient-seated isolation gate valves, air/vacuum valve components and the appurtenances necessary to provide a complete operable pumping-station discharge system.
• Provided a permanent emergency bypass connection to the force-main system together with maintenance provisions for the new pumping equipment. The station improvements incorporated a 4-inch bypass connection and a removable stainless-steel hoist system with a 2,000-pound-capacity hand-operated winch for future removal and servicing of the submersible pumps.
• Maintained wastewater conveyance throughout critical rehabilitation and tie-in activities using temporary bypass pumping. Extended shutdowns of the existing station were prohibited, and planned shutdowns generally had to occur during low-flow nighttime periods between 11:00 PM and 3:00 AM, with individual shutdowns limited to four hours.
• Provided redundant temporary pumping capacity during shutdowns and testing, with the specifications requiring at least two diesel-driven temporary pumps or two vacuum trucks. Each primary temporary pumping unit was required to handle the peak flow of the facility, while a second unit served as automatic or immediately available backup.
• Coordinated construction and final connections while minimizing interference with operation of the existing facility. New facilities were required to be completely tested and operational before final tie-ins were performed, and activities affecting valves, gates or station operations required advance coordination with Charles County.
• Completed civil and site improvements designed to improve drainage and eliminate standing-water conditions around the pump station. Associated work incorporated excavation and backfill, outside piping, concrete work, fencing, topsoil, turf establishment and restoration of areas disturbed by construction.
• Completed equipment testing, system start-up and a formal process demonstration prior to acceptance. The completed improvements were required to undergo between 5 and 14 consecutive days of operational demonstration, including average and peak flows as well as simulated equipment failures, overflows, surcharges and bypass conditions to demonstrate reliable operation under both normal and emergency scenarios.
• Coordinated project documentation and final turnover requirements, including shop drawings, equipment information, operation and maintenance documentation, record information, testing documentation and final system demonstration required for acceptance by Charles County.
• Johnston Construction Company served as the Prime Contractor for the White Plains Commerce Center Pump Station Upgrade for Charles County Government. The project involved extensive rehabilitation of an existing wastewater pumping station located at 10497 Theodore Green Boulevard in White Plains, Maryland. The existing station had been constructed in the mid-1980s and consisted of a wet well with submersible pumping equipment approximately 24 feet below grade.
• The existing pumping equipment was replaced with a new duplex submersible non-clog pumping system. Each new pump was designed for approximately 100 GPM at 32 feet of total head with the ability to pass solids up to at least 3 inches. Associated pump equipment incorporated guide and lifting systems, temperature and leakage monitoring and components designed to allow pumps to be removed for maintenance without personnel entering the wet well.
• The project also included construction of the new above-ground valve enclosure and associated process-mechanical piping. The completed system incorporated check valves, isolation valves, air/vacuum equipment and related wastewater-service piping and appurtenances. A 4-inch emergency bypass connection was incorporated into the discharge system, allowing temporary pumping equipment to connect to the force main when permanent pumping equipment was isolated for emergency or maintenance purposes.

B & R Electrical Contractors

• Performed the subcontracted electrical construction package for the White Plains Commerce Center Pump Station Upgrade, furnishing the labor, materials, tools and equipment required for the electrical work associated with the wastewater pumping-station improvements in accordance with Electrical Drawing E-1, Specification Section 16000 and project Addendum No. 1.
• Installed new conduit, conductors and electrical connections throughout the upgraded pumping-station systems, including raceways installed in accordance with the project's power one-line diagram and electrical details.
• Provided electrical raceway systems specifically suited to the different operating environments within the facility. Underground electrical installations utilized PVC conduit, while exposed wet-well installations utilized rigid metal conduit with stainless-steel support materials and explosion-proof provisions where required.
• Modified the existing electrical distribution equipment to support the upgraded pumping system, including replacement of an existing 80-amp, 240-volt, three-pole circuit breaker with a new 35-amp, 240-volt, three-pole breaker.
• Added new branch-circuit protection within the existing electrical panel, including a 20-amp, three-pole, 240-volt circuit breaker and a 20-amp, single-pole, 120-volt circuit breaker for the upgraded station equipment.
• Completed electrical connections to the new pumping equipment, including termination of manufacturer-provided pump cables within the pump controller and installation of conduit sealing bushings, cable seals and fittings required for a code-compliant installation.
• Removed existing conduit and wiring from the existing junction-box system as part of the electrical demolition and rehabilitation work necessary to transition the station to the new pumping and control equipment.
• Replaced existing motor-control devices with new integral lockable rotary switches, improving the isolation and servicing arrangement associated with the upgraded pumping equipment.
• Performed electrical testing of the completed installations as part of the subcontracted scope, supporting final verification and turnover of the electrical systems associated with the pump-station upgrade.
• B & R Electrical Contractors, Inc. completed the electrical construction package associated with the White Plains Commerce Center Pump Station Upgrade in White Plains, Maryland. Charles County Government was the Owner, Whitman, Requardt & Associates, LLP provided engineering services, and Johnston Construction Company served as the Prime Contractor. Historical JCC project records identify Shanna Reese as the County contact and Luis Quintanilla of Whitman, Requardt & Associates as the engineering contact.
• The overall project rehabilitated an existing wastewater pumping station and included improvements to the wet well, pumping equipment, valve enclosure, mechanical systems, controls and associated site infrastructure. BRE's work focused specifically on the electrical systems required to support the upgraded pumping equipment and controls.
• BRE furnished and installed the conduit, wiring, raceways and electrical connections included within its subcontract. The electrical installation was based on the project's power one-line diagram and associated electrical details. Underground raceways were specified as PVC conduit, while electrical installations within the wet-well environment utilized rigid metal conduit with stainless-steel support materials and explosion-proof installation requirements.
• Modifications to the station's existing electrical distribution equipment included replacement of an existing 80-amp, 240-volt, three-phase circuit breaker with a new 35-amp, 240-volt, three-pole breaker. BRE also installed new 20-amp, three-pole, 240-volt and 20-amp, single-pole, 120-volt circuit breakers within the existing panel to support the upgraded electrical equipment.
• The pump-related electrical work included termination of manufacturer-furnished cables within the pump controller. BRE provided the required conduit sealing bushings, cable seals and associated fittings to complete the installation in accordance with NEC requirements and the environmental conditions within the pumping station.