LEACHATE MANAGEMENT SYSTEM – PRETREATMENT FACILITY.
Johnston Construction Company
- The project included design, construction, startup, performance testing, and operation of a landfill leachate pretreatment facility at the Charles County Landfill in Waldorf, Maryland.
- JCC’s scope included design services, project management, engineering, permitting, mobilization, demobilization, all-weather equipment enclosure, treatment equipment, valves, piping, pumps, appurtenances, treatment system installation, startup, commissioning, performance testing, main control panel fabrication, factory acceptance testing, onsite testing, and one year of operations and maintenance.
- The system was designed to treat landfill leachate prior to discharge and to meet Charles County discharge requirements.
- Major work included installation of leachate pretreatment equipment, transfer pumps, process piping, valves, meters, controls, instrumentation, all-weather enclosure, electrical systems, HVAC, plumbing, generator, automatic transfer switch, main control panel, PLC, HMI, and SCADA integration.
- The project included a one-year O&M period after system startup, along with training for County staff so system operation could be transferred to the County.
Concrete Services Division
- CSD furnished the labor, form materials, tools, finishing supplies, curing materials, concrete accessories, and reinforcing-steel placement resources required for its assigned work.
- The principal CSD scope involved the forming and concrete placement of the new treatment-equipment foundations supporting the permanent landfill-leachate pretreatment system.
- The work included concrete placement, floating and screeding, curing, reinforcing-steel placement, special waterstop, premolded joint material, anchor-bolt setting, and associated concrete-accessory installation.
- CSD’s billing scope included approximately 172.58 cubic yards of slab-on-grade placement, approximately 2,309 square feet of slab-on-grade forming, approximately 1,909 square feet of floating and screeding, and approximately 12.94 tons of reinforcing-steel placement.
- CSD coordinated concrete purchased by Johnston Construction Company, concrete-pumping services, testing-laboratory activities, reinforcing-steel unloading, and JCC-provided equipment used during concrete operations.
Electrical Services Division
- ESD furnished and installed the project’s conduit, wiring, electrical connections, lighting, switches, receptacles, electrical service components, panelboard equipment, surge protection, and lightning-protection system.
- The electrical scope included extensive underground distribution, including power and control ductbanks serving the treatment facility, existing leachate storage tanks, new process tank, meter vault, sump pit, and other process-system locations.
- ESD installed power, digital-control, analog-control, and spare conduits serving the new and existing tanks, meter vault, and sump-pump area.
- ESD’s work incorporated pull boxes for the underground electrical system, including five pull boxes associated with the power ductbank and five associated with the fiber-routing system.
- ESD furnished and installed a 30-kVA, 480-to-208-volt transformer and performed electrical interconnections associated with pre-wired treatment-system containers.