Greeley and Hansen, A TYLin Company, evaluated and designed an innovative covered composting system at the Calumet Water Reclamation Plant to explore beneficial reuse of biosolids.
The Beneficial reuse of biosolids is a critical component to achieve resource recovery goals and a sustainable Biosolids Management Program, while saving costs, managing odors, and the potentially generating an additional revenue stream.
The Metropolitan Water Reclamation District of Greater Chicago retained Greeley and Hansen to implement a covered composting system at its Calumet Water Reclamation Plant. Serving one million customers on the south side of the City of Chicago with a design maximum flow of 430 MGD, digested solids at the activated sludge single-stage nitrification plant are sent to onsite lagoons for thickening and then drying beds prior to land application. The composting system was based on an annual solids production of 25,000 dry tons and a biosolids feedstock with 15 to 25 percent solids content.
The Mixing and Receiving Building included a new pug mill mixer and conveyance in and out of the building for material. The space presented a unique challenge to meet National Fire Protection Association compliance goals. The combination of dewatered biosolids and feedstock material presented challenges for both dust and hazardous gases. The project team evaluated the standards to determine the area classification and then selected design criteria for equipment within the Mixing and Receiving Building. The project was completed from preliminary design through bid services. After bidding, it was determined to not construct the project due to reliability of a sustainable source of feedstock material.
Site improvements to support the new buildings and structures.
Mixing and Receiving Building to receive and store 125,000 tons of biosolids annually, as well as have the potential for infrastructure to accommodate future unprocessed yard and tree waste for bulking material.
Design of the three-phase covered composting system
Conveyance of solid material between the Mixing and Receiving Building and throughout the three composting phases, with the ability to accept a conveyor from the Dewatering Building in the future.
Odor control for the Mixing and Receiving Building and potential Screening Building through a bio-filter.
Consideration of additives to the composted material to create designer products that can be tailored to different markets.