Fort Meade Wastewater Treatment Plant Grit Removal System Rehabilitation

Key Accomplishments

Concrete Services Division

• CSD furnished the labor, tools, form materials, form lumber, finishing supplies, curing supplies, accessories, and supervision required for concrete fill and concrete weir-wall construction within the grit-chamber structure.
• The concrete scope included forming and placing slabs on grade, straight walls, concrete fill, and special concrete placements associated with the rehabilitated grit chamber.
• CSD installed and stripped concrete formwork required to establish the new weir-wall and slab configurations.
• CSD installed concrete accessories including waterstops, premolded joint material, caulking, and related embedded components.
• CSD provided labor for installation of reinforcing-steel dowels and coordinated reinforcing-steel placement associated with the concrete modifications.
• CSD coordinated placement of anchor bolts and sleeves required for the grit-system improvements.
• Concrete work was performed within an existing wastewater-treatment structure and required careful coordination with the new grit-removal equipment, process piping, aeration components, and electrical systems.
• CSD coordinated concrete deliveries, testing laboratory activities, pumping services, equipment use, and construction sequencing with project management and other trades.
• The scope included winter-protection labor and coordination to support proper concrete placement and curing during cold-weather conditions.
• CSD operated project equipment furnished for the work, including material-handling equipment, skid-steer equipment, and boom-truck equipment when required.
• The work was performed in accordance with the project’s cast-in-place concrete requirements and issued-for-construction grit-system drawings.
• CSD’s concrete modifications helped create the structural configuration needed to support the new automated grit-removal process and associated hydraulic improvements.

Electrical Services Division

• Electrical Services Division provided the electrical construction required for rehabilitation of the grit removal system at the Fort George G. Meade Wastewater Treatment Plant.
• The project included installation of a new automated inclined screw-conveyor grit removal system designed to handle wastewater flows of up to 4.5 million gallons per day.
• ESD furnished the labor, materials, tools, supervision, conduit, wiring, connections, electrical equipment, testing, and startup support required for the new grit-removal equipment and associated blower.
• The electrical scope included two new motor-control-center buckets, with one serving the grit-removal system and one serving the replacement blower.
• ESD provided separate disconnecting means for the grit system and blower and installed the associated electrical rack for control panels and disconnect equipment.
• Power distribution included 480-volt power for the grit system and blower, along with 120-volt circuits for heat tracing and area lighting.
• Control work included wiring for run commands, fault indication, run-status indication, level sensing, and potential solenoid-valve connections associated with the grit-removal process.
• ESD installed exposed galvanized rigid conduit and underground PVC conduit suited for the wastewater-treatment environment.
• The work included use of existing underground conduit pathways from the operations building and construction of a concrete-encased electrical ductbank extending from the existing handhole system to the new grit-removal equipment.
• ESD installed two new light fixtures near the grit system to improve illumination around the operating and maintenance area.
• The project included electrical heat tracing for applicable piping and equipment exposed to outdoor conditions.
• ESD supported installation of a level sensor and associated 4–20 mA control wiring required for monitoring the grit-removal process.
• An arc-flash analysis was included to evaluate the modified electrical system and support proper equipment labeling and personnel safety.
• ESD coordinated its work with wastewater-treatment operations, project management, equipment manufacturers, controls personnel, and other construction trades while the active treatment plant remained in operation.