The DeKalb Sanitary District WWTP process includes tertiary filtration. The tertiary filter cells and backwash pumps were rehabilitated as part of the Biosolids Phase 1A Improvements. The Facility Plan had identified additional improvements for later phases; however budgetary constraints limited the scope of the first project. Recognizing this, the Illinois EPA elected to provide the District additional Stimulus ARRA funds which were left over from the first round of funding.
The scope of the project included replacement of the existing building and electrical/control system, rehabilitation of the screw pumps, and replacement of the NPW system and chemical feed systems. As part of the new building, all HVAC, electrical, lighting, grating, and structural components were replaced.
Through staged construction, installation of temporary systems, and project coordination, the entire project was completed without removing the tertiary filters or screw pumps from service.