Trotter and Associates, Inc. (TAI) worked alongside Joseph J. Henderson & Son, Inc, (JJH) to construct the new RAS/WAS Pump Station and two 45-foot diameter tertiary clarifiers as part of the DuPage County Nordic Wastewater Treatment Plant Rehabilitation project. This structure serves as a means of separating and conveying Waste Activated Sludge (WAS) and Return Activated Sludge (RAS). From this facility, WAS is conveyed to the sludge storage tank for decant and haul-off from the site, and RAS is returned to the Aeration Basins that precede the Tertiary Clarifiers in the plant’s process flow.

The rehabilitation of the Nordic Plant includes form liners that are fastened to the inside of the formwork prior to casting new exterior concrete walls around the site, resulting in the appearance of stone masonry. These were incorporated as an alternative to masonry to improve aesthetics while reducing cost, maintenance, and construction duration of the project. TAI worked closely with JJH to ensure these form liners were laid out and installed to achieve a uniform and seamless finish which is difficult to create in most form liner applications. The Tertiary Clarifiers and RAS/WAS Station make up the first structure completed with concrete as part of this rehabilitation. The entire project team could not be more pleased with the result from both an aesthetic and structural standpoint. Now that the bones of the structure are complete, next up are the aluminum geodesic domes for the clarifiers, process and electrical equipment, and finish carpentry.