Route 925B Pump Station Replacement

Key Accomplishments

Johnston Construction Company

• The work included a permanent emergency dry-prime bypass-pumping system and concrete equipment pad to support continuity of wastewater service during emergency or maintenance conditions.
• JCC installed new suction and discharge piping, valves, fittings, bypass connections, pipe supports, wall sleeves, flexible connections, and related mechanical appurtenances.
• The project included new electrical service equipment, panelboards, motor starters, grounding and bonding, lighting, power and control wiring, instrumentation, and surge protection.
• The existing pumping facilities were demolished or abandoned after the replacement station was tested, commissioned, and placed into operation.
• Civil improvements included excavation, dewatering, site utilities, paving, driveway and parking improvements, grading, erosion and sediment controls, fencing, and final restoration.
• JCC coordinated equipment testing, electrical field-acceptance testing, pump startup, functional testing, operator training, record drawings, operation and maintenance manuals, and final project turnover.
• Whitman, Requardt & Associates, LLP prepared the project design and specifications and provided engineering and construction-phase services for Charles County.
• The project replaced the existing Route 925B wastewater pumping facilities with a new station designed to provide improved reliability, maintainability, emergency-operating capability, and control of wastewater flows.
• The new facility included an approximately 10-foot-inside-diameter wet well equipped with submersible wastewater pumps. The project geotechnical information also identified a new approximately 10-foot-by-12-foot mechanical and electrical building, an emergency bypass pump on a concrete slab, a driveway entrance, and parking improvements.
• JCC coordinated the complete construction effort, including project scheduling, submittals, procurement, temporary facilities, safety, excavation, dewatering, concrete construction, mechanical installation, electrical systems, controls, commissioning, training, and closeout.
• The work began with site preparation and coordination of existing underground utilities and active wastewater infrastructure.
• JCC established the limits of construction, protected existing facilities designated to remain, and implemented the required erosion and sediment-control measures.

Concrete Services Division

• CSD furnished the labor, form materials, tools, equipment, finishing supplies, curing materials, and concrete accessories required for its assigned work.
• The concrete scope included construction of the precast mechanical and electrical building base slab.
• The work included concrete equipment-support pads and pipe and valve supports serving the replacement wastewater pumping station.
• CSD furnished and installed the required formwork and coordinated concrete dimensions, elevations, anchor bolts, penetrations, and embedded components with Johnston Construction Company.
• The project included concrete placement, consolidation, floating, screeding, machine troweling, pointing, patching, finishing, and curing.
• CSD placed flowable fill associated with abandonment and closure of designated portions of the existing pumping facilities.
• The work included construction of concrete sidewalks and other exterior concrete features required for safe access around the new station.
• CSD coordinated concrete deliveries, pumping services, testing, winter protection, equipment access, and placement sequencing with Johnston Construction Company.
• The overall project included construction of a replacement wastewater pumping station for Charles County Government, including a new wet well, submersible pumps, mechanical and electrical building, emergency bypass-pumping system, process piping, electrical equipment, controls, civil improvements, and site restoration.
• CSD performed the designated forming, placement, finishing, curing, and concrete-accessory work required to support the new pumping facilities.
• The subcontract specifically included concrete construction for the precast building base slab, bypass-pump equipment foundation, equipment-support pads, pipe and valve supports, flowable-fill placement, and sidewalks.
• The work began with coordination of the prepared subgrades, foundation limits, elevations, underground utilities, piping penetrations, conduit locations, and equipment layouts provided by Johnston Construction Company.
• CSD verified that the work areas were accessible and ready before beginning the formwork and concrete-placement operations.
• The principal concrete feature was the base slab supporting the new mechanical and electrical building.