LocationHagerstown, Washington County, Maryland
MarketWastewater Treatment Plants
DeliveryDesign-Build
DESIGN-BUILD DIGESTER CONVERSION, SLUDGE STORAGE, AERATION, PROCESS PIPING & SCADA INTEGRATION.
Johnston Construction Company
- Johnston Construction Company served as the Design-Build Subcontractor for the conversion of existing Secondary Digester No. 2 into an additional sludge holding tank at the Hagerstown Wastewater Treatment Plant. The project RFP specifically defined the tank conversion as a Design-Build task.
- Managed a comprehensive Design-Build delivery process encompassing existing-condition evaluation, engineering coordination, design development, construction management, construction, commissioning and final turnover.
- JCC retained and coordinated GHD, Inc. as its Design Engineer for the engineering portions of the Design-Build scope and participated in initial, 30%, 60% and 90% design workshops with Synagro and the City of Hagerstown.
- Provided final design drawings and specifications along with as-built documentation, equipment information, project scheduling and operations and maintenance documentation as part of the completed Design-Build system.
- Converted the existing digester into an approximately 243,000-gallon sludge storage tank, supporting a two-tank system with approximately 486,000 gallons of total sludge-storage capacity.
Electrical Services Division
- Electrical Services Division, LLC served as the Trade Subcontractor supporting Johnston Construction Company’s Design-Build conversion of Secondary Digester No. 2 into an additional sludge holding tank at the Hagerstown Wastewater Treatment Plant.
- Performed the electrical power, control and instrumentation work associated with the new sludge-storage aeration system, including two new 75 HP positive-displacement blowers and their VFD control systems.
- Demolished the existing Panel DGA and installed a new 600A, 480/277V, NEMA 12 power panel, including a 600A main breaker with adjustable trip and dedicated breakers serving the two new blower systems.
- Installed an aluminum equipment backboard in the blower area to support the two VFD blower control panels and associated safety disconnect switches.
- Furnished and installed conduit, conductors and electrical connections to provide 480V power from the new distribution panel to both VFD blower control panels and the two 75 HP blowers.