PC-757 Rehabilitation of Primary Clarifiers

Tooles-Allied was awarded the Rehabilitation of the Rectangular Primary Clarifiers, Electrical/Mechanical Buildings and Pipe Gallery and Replacement of Rake Arm Assembly for Circular Primary Clarifiers No 15 and 16 Project. This four-year project is located at the Detroit Wastewater Treatment Plant and involves three packages.

Package A Summary: Demolition and installation of all mechanical sludge and scum collection equipment within the clarifiers including shafts, sprockets, chains, flights, rails, brackets and supports. Demolition and installation of the steel scum troughs, rails, beaches, the scum drives and chain guards. Modification of the concrete pads as required to accommodate the new scum drives. Demolition and installation of all sludge main and cross collector drives, sludge collector and cross collector motors, local disconnect / control enclosures and associated above ground electrical conduit. Perform concrete repairs and rehabilitation to the primary clarifiers including concrete surface repairs of spalls and de-laminations. Demolition and then installation of the clarifier drain valves located within the manholes adjacent to the Electrical/Mechanical buildings.

Package B Summary: Complete demolition and replacement of all existing makeup air units for Electrical/Mechanical (E/M) buildings No. 1-6 and pipe gallery, including complete demolition and replacement of metal air ducts in the E/M buildings and the pipe gallery. Complete demolition and replacement of major equipment in the pipe gallery of the rectangular primary clarifiers, including 12 sludge pumps, 5 chopper sump pumps and 112 primary clarifier influent inlet gate valves. Complete demolition and replacement of 56 clarifier inlet slide gates and operators. Complete demolition and replacement of all insulated steam and condensate piping in the pipe gallery and the six E/M buildings, including demolition of pipe insulation that contain asbestos. Select demolition and replacement of the process and utility piping and valves in the pipe gallery, including piping that is coated with lead paint.

Package C Summary: Demolition and replacement of the following major components of the Circular Primary Clarifiers Nos. 15 & 16: center drive cages, drive ring adapters, influent dispersion wells, influent dispersion well supports, full length rotating rake arms/spiral blades/squeegees (4 assemblies in each clarifier), 4 short rake arms in Clarifier No. 15 , sludge hopper scrapers. Removal and reinstallation of existing scum deflectors, skimmer arms, skimmer arm and scum deflector supports, neoprene hinges and C-cups in Clarifiers Nos 15 & 16. Removal & replacement of perimeter handrails as well as handrails on bridges of Clarifiers Nos. 15 & 16.