Fort Meade Wastewater Treatment Plant Ultraviolet Redundant System

Key Accomplishments

Johnston Construction Company

• The redundant system was designed to treat wastewater flows ranging from approximately 0.5 million gallons per day to a peak flow of 2 million gallons per day.
• JCC provided six ultraviolet reactors, with one reactor installed on each 12-inch outlet pipe serving the existing sand filters inside the WWTP Filter Building.
• The reactors were designed for submerged, full-pipe wastewater service and incorporated 316L stainless-steel piping with ANSI 150 flanged connections.
• Each reactor included variable-power ultraviolet lamps, high-purity quartz sleeves, dry UV-intensity monitors, an automatic low-voltage wiping system, a one-piece wiper ring, temperature sensing, drain and vent connections, and an access hatch.
• JCC furnished six dedicated free-standing power and control cabinets that provided redundant control capability for the ultraviolet-treatment process.
• The control cabinets included NEMA 12 enclosures, HMI touchscreens, electronic ballasts, power supplies, microprocessor controls, warning alarms, data logging, remote monitoring, and MODBUS-over-Ethernet communications.
• Thirty-six molded lamp cables and six sensor and motor cable kits were incorporated into the new equipment installation.
• JCC furnished and installed six 12-inch isolation valves, allowing individual reactors to be isolated for maintenance and operation without disabling the entire redundant system.
• Six 2-inch air-release valves were installed, one for each UV reactor, with discharge piping directed to an interior floor drain or sump.
• The air-release-valve arrangement was coordinated with the reactor manufacturer’s recommended placement upstream and downstream of each reactor.
• JCC provided the electrical power, conduit, wiring, boxes, fittings, terminations, controls equipment, and associated components required for the new ultraviolet system.
• Electrical power was extended from the existing motor-control center in the Filter Building through installation of a new MCC bucket and related distribution equipment.

Electrical Services Division

• Electrical Services Division, LLC performed the electrical construction associated with the new redundant ultraviolet disinfection system at the Fort Meade Wastewater Treatment Plant.
• The overall design-build project installed six new ultraviolet reactors on the outlet piping from the existing sand filters inside the WWTP Filter Building.
• The redundant UV system was designed to help maintain continuous effluent disinfection if the existing ultraviolet equipment became unavailable because of electrical failure, controls malfunction, maintenance, or another system interruption.
• ESD furnished the labor, materials, tools, supervision, conduit, wiring, boxes, devices, switchgear, and electrical connections required for the new UV equipment.
• The electrical scope included two new 200-amp lighting panelboards serving the redundant ultraviolet system.
• ESD furnished and installed two new 200-amp motor-control-center buckets to provide power distribution for the six UV equipment panel loads.
• ESD coordinated the new MCC equipment with the available space and electrical capacity within the existing MCC9 installation.
• The work included electrical distribution from the existing motor-control center to the new UV power and control cabinets.
• ESD installed conduit and wiring for the UV equipment, panelboards, control cabinets, and associated electrical loads.
• The electrical installation included boxes, fittings, devices, terminations, equipment connections, and related accessories necessary for a complete operating system.
• ESD provided portions of the conduit routing between the UV panels and reactor lamps for smaller instrumentation cables.
• The work required coordination with the six UV reactors, six power and control cabinets, factory-furnished reactor cables, process piping, valves, and control equipment.
• ESD coordinated electrical clearances and equipment locations with JCC’s project layout for the UV cabinets, panelboards, and remote telemetry equipment.
• The project included electrical demolition necessary to accommodate the new distribution and equipment connections.

Additional project details

• The purpose of the project was to provide redundancy to the wastewater treatment plant’s existing ultraviolet disinfection process.