LocationJessup, Howard County, Maryland
MarketWastewater Treatment Plants
BELT FILTER PRESS DEMOLITION, CENTRIFUGE INSTALLATION, POLYMER STORAGE AND FEED SYSTEM, SHAFTLESS SCREW CONVEYORS, PROCESS PIPING, STRUCTURAL MODIFICATIONS, ELECTRICAL SYSTEMS, INSTRUMENTATION, CONTROLS, TESTING, STARTUP.
Johnston Construction Company
- The project replaced two existing belt filter presses with two new high-speed centrifuge systems, including associated piping, valves, drives, controls, instrumentation, and sludge-discharge equipment.
- JCC replaced the existing polymer-feed equipment with a new liquid polymer storage and feed system consisting of a polymer storage tank, blending systems, solution pumps, venturi mixers, piping, controls, and instrumentation.
- The project included demolition and removal of existing belt filter presses, chemical tanks, associated piping, supports, electrical equipment, controls, and other sludge-processing components.
- JCC installed new shaftless screw conveyors to transfer dewatered sludge cake from the centrifuges to the existing downstream belt conveyor and lime-stabilization system.
- The work was carefully phased so that one existing belt filter press or one new centrifuge remained available for operation throughout construction, except for approved short-duration shutdowns.
Concrete Services Division
- CSD constructed concrete curbs, equipment pads, troughs, slabs, walls, columns, and pedestals required to support the new centrifuges, polymer-storage and feed equipment, shaftless screw conveyors, process piping, and related sludge-dewatering systems.
- The work included footing forms, slab-on-grade forms, straight-wall forms, column forms, concrete placement, floating, screeding, machine troweling, pointing, patching, floor hardener, curing, and concrete accessories.
- CSD installed approximately 150 square feet of footing forms, 195 square feet of slab-on-grade forms, 200 square feet of straight-wall forms, and 256 square feet of column forms.
- CSD placed approximately 27.51 cubic yards of slab-on-grade concrete, 1.85 cubic yards of wall concrete, and 3.16 cubic yards of column concrete.
- Concrete accessories included vapor barrier, special waterstop, premolded joint material, joint sealing, anchor-bolt and dowel coordination, and related materials necessary for complete concrete construction.
B & R Electrical Contractors
- BRE’s scope included electrical demolition, conduit, conductors, boxes, devices, equipment connections, switchgear modifications, instrumentation wiring, inspection, testing, startup, and project closeout.
- BRE made the existing electrical equipment safe for demolition before Johnston Construction Company removed the existing belt filter presses, chemical tanks, piping, and associated sludge-processing equipment.
- The work included two new 125-amp motor-control-center buckets, one dual-mounted 20-amp MCC bucket assembly, a 15 kVA transformer, 100-amp Panel D, and a 30-amp non-fused disconnect switch.
- BRE modified the existing conveyor control panel to integrate the new centrifuge and shaftless screw-conveyor equipment with the plant’s existing sludge-handling system.
- Electrical and instrumentation raceways and conductors were installed for the two new centrifuges, polymer storage and feed system, conveyors, process equipment, control panels, and associated field devices.