St. Michaels Water System Improvements – Marengo & Glory WTPs

Key Accomplishments

• Executed the work through a carefully phased construction sequence to maintain the Town's drinking-water supply. At the start of construction, the Marengo WTP was idle and the Glory WTP was providing the Town's full water supply; Glory was required to remain continuously operational until the Marengo improvements were completed and placed into service.
• Completed initial erosion and sediment-control work followed by construction of new treatment tanks, piping and process equipment at the Marengo WTP.
• Coordinated improvements at the active Glory WTP that could be completed without interrupting treatment, then placed the renovated Marengo facility into service before completing the remaining Glory WTP improvements.
• Provided the project arsenic-removal pressure-filtration system, designed specifically for treatment of groundwater containing arsenic.
• The specified pressure-filtration system was designed for approximately 226 GPM total flow, with 113 GPM per filter unit, a design loading rate of approximately 7.99 GPM/SF, and a normal maximum operating pressure of 100 PSI.
• Furnished filtration media using GreensandPlus, with approximately 42 cubic feet of media per filter and an 18-inch media-bed depth, supported by graded gravel and a non-ferrous hub-and-lateral underdrain/backwash system.
• Integrated the arsenic-removal filters with the plant's backwash system, including filtered-water backwash supply, filter controls, level monitoring and associated process piping.
• Furnished and installed comprehensive chemical-feed equipment and accessories required for the upgraded water-treatment process. The specifications required complete chemical-feed assemblies together with injection equipment, controls, accessories and field testing.
• Installed chemical injection systems supporting hydrochloric acid at both treatment plants, ferric chloride at Marengo and chlorine treatment at both Marengo and Glory, including CPVC injection equipment and connections to the water mains.
• Furnished dedicated chemical-storage tanks designed for hydrochloric-acid service, including secondary system components, flexible connections, restraints, piping interfaces and field testing.
• Installed associated chemical-system safety and process components including pressure-relief devices, check valves, injection assemblies, containment monitoring and emergency eyewash/shower alarm interfaces.
• Constructed the project's new masonry treatment building and associated architectural and building systems required to house process equipment.