Rolling Mill and Leslie Water Treatment Plants Powder Activated Carbon Systems

Key Accomplishments

Johnston Construction Company

• Installed PAC feed hoppers, feeder and mixer equipment, drive-control panels, chemical-feed tubing, process piping, valves, flow-control components, supports, and associated appurtenances.
• Furnished and installed dust-collection systems serving the powder activated carbon handling equipment.
• Relocated and replumbed the existing sodium-chlorite feed system at the Rolling Mill Water Treatment Plant.
• Demolished and modified portions of the existing Rolling Mill chemical room to accommodate the new PAC feed and dust-collection equipment.
• Upgraded HVAC, exhaust ventilation, motorized dampers, heaters, lighting, and electrical systems within the Rolling Mill carbon-feed area.
• Installed carbon-feed conduit and tubing from the Rolling Mill feed equipment to the existing clarifier injection points.
• Constructed a reinforced-concrete foundation and pad for a new prefabricated fiberglass chemical shelter at the Leslie Water Treatment Plant.
• Furnished and installed a new 10-foot by 10-foot by 10-foot insulated fiberglass shelter for the Leslie PAC feed system.
• Installed heating, air conditioning, ventilation, hazardous-location electrical systems, lighting, controls, and safety equipment within the new Leslie chemical shelter.
• Installed PAC process piping from the Leslie shelter to the existing chemical injection point within the treatment building.
• Installed electrical breakers, disconnects, conduit, wiring, control connections, grounding, and equipment power at both treatment plants.
• Coordinated instrumentation, remote start and stop signals, control-panel interfaces, and integration with the Town’s existing SCADA system.

B & R Electrical Contractors

• B & R Electrical Contractors, Inc. performed the electrical construction associated with new powder activated carbon feed systems at the Rolling Mill and Leslie Water Treatment Plants.
• Furnished and installed conduit, conductors, boxes, devices, supports, terminations, and electrical connections serving the new PAC equipment at both treatment plants.
• Installed power and control connections for two PAC feeder-drive control panels, two dust-collection systems, two solenoid valves, and HVAC equipment furnished by Johnston Construction Company.
• Furnished and installed four NEMA 4X electrical disconnects, including two at the Rolling Mill Water Treatment Plant and two at the Leslie Water Treatment Plant.
• Installed two Class II, Division 2 light fixtures within the Rolling Mill PAC handling area.
• Modified existing electrical panels and installed compatible circuit breakers for the new PAC feeder, dust collector, HVAC, and related equipment loads.
• Performed electrical demolition and made existing circuits safe before removal or relocation of mechanical and chemical-feed equipment.
• Installed power wiring from vendor-furnished control panels to feeder motors, mixer motors, dust-collector fans, shaker motors, and related equipment.
• Provided flexible raceway connections at vibrating equipment in accordance with the equipment manufacturers’ requirements.
• Coordinated electrical connections with the prefabricated fiberglass PAC shelter, process equipment, HVAC systems, chemical-feed piping, and controls furnished by others.
• B & R Electrical Contractors, Inc. performed the electrical construction for the Rolling Mill and Leslie Water Treatment Plants Powder Activated Carbon project in North East, Maryland.
• The overall project provided new powder activated carbon feed systems at two active municipal water-treatment facilities. Johnston Construction Company served as the prime contractor for the Town of North East, and Entech Engineering, Inc. served as the project Engineer. The overall work included PAC feed equipment, dust collection, chemical-feed piping, HVAC, electrical construction, controls integration, a new fiberglass chemical shelter at Leslie, concrete work, testing, training, and restoration.
• The electrical work was performed in connection with the PAC feed systems installed at both plants. These systems included feed hoppers, feeder and mixer assemblies, dust collectors, vendor-furnished control panels, chemical-feed tubing, ventilation equipment, and related process components.
• At the Rolling Mill Water Treatment Plant, B&R performed electrical demolition within the existing chemical-feed area. Existing circuits were identified, disconnected, isolated, and made safe before Johnston Construction Company removed or relocated the associated mechanical equipment, chemical-feed systems, and heaters.