Lower Allen Township WWTF Gravity Thickener Improvements

Johnston Construction Company

• Rehabilitated two existing 40-foot-diameter gravity thickeners, each enclosed by a fiberglass dome, while maintaining operation of the active Lower Allen Township Authority wastewater treatment facility.
• Removed the existing drive motors and gear-drive units from Gravity Thickener No. 1 and No. 2 and installed new motors and gear-drive assemblies supporting the existing bottom scrapers, center wells, and skimmer systems.
• Removed and replaced the center column in each thickener and modified the existing steel center cages and walkway deck plates to accommodate the new drive assemblies while maintaining future maintenance access.
• Replaced the existing sludge feed piping within each center column with new 10-inch Schedule 40 stainless-steel sludge feed lines.
• Added a second scum skimmer arm to each thickener, modified and rebalanced the skimmer assemblies, and installed new stainless-steel bottom scraper squeegees.