LocationLa Plata, Charles County, Maryland
MarketWastewater Treatment Plants
ULTRAVIOLET DISINFECTION SYSTEM REPLACEMENT, UV CHANNEL CONSTRUCTION, CONCRETE DEMOLITION, SLIDE GATES, STOP-LOG FRAMES, STRUCTURAL METALS, PROCESS PIPING, ELECTRICAL SYSTEMS, CONTROLS, SCADA CONNECTIONS, TESTING, COMMISSIONING.
Johnston Construction Company
- Johnston Construction Company performed the construction and installation work associated with the Mattawoman Wastewater Treatment Plant Energy-Saving Improvements UV System Upgrade.
- The project included replacement of the plant’s existing ultraviolet disinfection equipment with three new UV disinfection systems, together with new concrete channels, slide gates, stop-log frames, access walkways, railings, electrical systems, instrumentation, controls, and SCADA connections.
- JCC constructed the new UV System No. 3 channel first, followed by phased demolition and replacement of existing UV System Nos. 2 and 1.
- The project included temporary bulkheads, channel draining, pumping, dewatering, cleaning, shutdown coordination, concrete demolition, reinforced-concrete construction, equipment installation, and restoration.
- JCC installed new influent slide gates, stop-log frames, utility-water channel interconnections, effluent-control components, structural grating, stairs, handrails, and aluminum diamond-plate channel covers.
Concrete Services Division
- CSD constructed the reinforced-concrete channels, walls, slabs, footings, supported slabs, equipment-support areas, and structural modifications required for three new ultraviolet disinfection systems.
- The work included approximately 213 cubic yards of concrete associated with the phased UV-channel improvements.
- CSD installed footing forms, slab-on-grade forms, straight-wall forms, supported-slab forms, reinforcing dowels, vapor barrier, waterstop, and related concrete accessories.
- The project included approximately 416.88 square feet of footing forms, 730.33 square feet of slab-on-grade forms, 1,197.49 square feet of straight-wall forms, and 73.50 square feet of supported-slab forms.
- CSD placed approximately 158.35 cubic yards of slab-on-grade concrete, 109.96 cubic yards of wall concrete, and 1.44 cubic yards of supported-slab concrete under the subcontract’s detailed billing quantities.
Electrical Services Division
- ESD furnished and installed the conduit, conductors, connections, boxes, devices, electrical gear, lighting, instrumentation raceways, underground ductbank, and related electrical components required for three new ultraviolet disinfection systems.
- The electrical distribution work included ten 30-amp disconnect switches, three 100-amp disconnect switches, three 100-amp circuit breakers, three 30-amp circuit breakers, one 20-amp circuit breaker, and three power-meter totalizers.
- ESD installed power and control conduit and wiring for three UV-transmittance transmitters, with one transmitter serving each new UV disinfection system.
- The project included control conduit for high- and low-level floats serving the three UV channels and additional floats incorporated into ESD’s revised scope.
- ESD installed power and control wiring for the motor-operated weir gates and utility-water slide gate associated with the UV-treatment channels.