Aberdeen Proving Ground WWTP Digester No. 1 Cover Replacement

Key Accomplishments

• The project included draining and cleaning Digester No. 1 so the interior structure, gas piping, and other components could be inspected.
• JCC coordinated concrete repair and protective coating work within the digester where deteriorated areas were identified.
• Existing digester gas-withdrawal piping was inspected, with damaged piping replaced using Schedule 10 Type 316L stainless steel where required.
• New cover-level sensors, field instruments, electrical raceways, conductors, grounding, control components, and associated connections were installed and coordinated with the replacement cover.
• Construction was carefully sequenced to minimize disruptions to the operating wastewater-treatment plant and maintain safe access for facility personnel.
• JCC coordinated manufacturer services, acceptance testing, startup, operator training, record documentation, warranties, and final project closeout.
• Johnston Construction Company served as the prime contractor for the Aberdeen Proving Ground Wastewater Treatment Plant Digester No. 1 Cover Replacement project in Aberdeen, Maryland.
• The project was completed for the City of Aberdeen Department of Public Works at the wastewater-treatment facility located within Aberdeen Proving Ground in Harford County.
• The project addressed the existing secondary digester and its floating gas-holder cover.
• The original cover was removed and replaced with a new rigid steel, self-supporting floating cover designed to operate on the digester gas and accommodate the required internal and external loading conditions.
• The new cover system included the structural cover assembly, seals, guides, supports, safety equipment, accessories, instrumentation interfaces, coatings, and components required for proper operation.
• JCC began the work by developing the detailed project schedule, construction sequence, site-safety procedures, equipment-handling plan, and temporary-facility requirements.