Aberdeen Proving Ground 0.5 MG Elevated Water Storage Tank – Mixer Installation & Rehabilitation

Key Accomplishments

Johnston Construction Company

• Upgraded the originally specified mixing equipment to a larger PAX 400 mixer to provide increased mixing capability.
• Installed the mixer support system and coordinated structural attachment of the mixer bracket to the existing tank overflow piping.
• Pressure washed the existing elevated water tank and completed coating touch-up and repair at areas affected by construction and welding.
• Completed associated electrical and control-system improvements necessary to support the new mixer and upgraded tank systems.
• Installed a new electrical equipment enclosure and coordinated power, controls, grounding, conduit, wiring, and equipment connections.
• Upgraded the tank's obstruction-lighting system and installed an electrified bird-deterrent system.
• Integrated City-furnished remote telemetry and antenna equipment for monitoring of the upgraded tank systems.
• Sequenced demolition, electrical modifications, and system changeovers to minimize disruption to the operating public water-storage facility.
• Completed potable-water tank cleaning, disinfection, bacteriological testing, and VOC testing prior to return to service.
• Performed construction within the restricted Aberdeen Proving Ground facility, requiring controlled access, security coordination, and project-specific site procedures.
• Johnston Construction Company served as the Prime Contractor for improvements to the City of Aberdeen's existing 0.5 MG elevated water storage tank at Aberdeen Proving Ground. The project combined mechanical equipment installation, tank rehabilitation, electrical and control-system improvements, telemetry, safety equipment, coating repairs, disinfection, testing, and startup within an operating public water system.
• The primary process improvement involved furnishing and installing a new PAX Water Technologies submersible tank mixing system. The mixer was designed for continuous operation within the potable-water storage tank to promote circulation and reduce water stagnation. The project specifications originally identified a PAX PWM 200 unit with a stainless-steel submersible motor and impeller, dedicated controls, and associated electrical connections.

Electrical Services Division

• Performed the electrical construction associated with improvements to an existing 0.5-million-gallon elevated water storage tank at Aberdeen Proving Ground.
• Completed electrical demolition of existing conduit and wiring and installed new conduit, conductors, connections, switches, receptacles, and associated electrical infrastructure.
• Installed electrical systems supporting the new PAX Water Technologies tank mixing system, including modifications required when the project was upgraded to the larger PAX mixer.
• Relocated the existing LP panelboard and vault exhaust-fan timer as part of the tank electrical improvements.
• Furnished and installed a 72-inch x 72-inch x 12-inch NEMA 12 electrical equipment enclosure complete with lighting, exhaust fan, intake fan, heater, and door switches.
• Installed the tank's new obstruction-lighting system, including electrical power, controls, and associated wiring.
• Installed the electrified bird-deterrent system and later provided additional bird-barrier material as part of an approved project change.
• Installed the intrusion-alarm panel and supporting electrical components.
• Mounted the City-furnished telemetry antenna and completed associated wiring and coordination for integration with the tank's remote telemetry system.
• Maintained existing electrical systems during construction and coordinated shutdowns and switchovers to minimize disruption to the operating water-storage facility.
• Completed additional electrical work associated with the larger mixer installation, including revised conductor requirements and electrical modifications.
• Provided electrical testing, startup coordination, submittal and O&M review, and as-built/record documentation upon completion.
• Electrical Services Division, LLC served as the Electrical Subcontractor to Johnston Construction Company for the Aberdeen Proving Ground Elevated Water Storage Tank Mixer Installation project. The work supported upgrades to an existing 0.5 MG potable-water storage tank owned and operated by the City of Aberdeen at Aberdeen Proving Ground.
• ESD's subcontract required the division to furnish the labor, materials, tools, supervision, equipment, and supplies necessary to complete the electrical work for the elevated water storage tank mixer system in accordance with the ARRO Consulting project drawings and Division 16 electrical specifications.