Midwest Utility Company
Dry Fly Ash Storage Site
Our team provided civil and structural engineering design for wet-to-dry fly ash conversion and storage site.
This client needed to decommission their existing fly ash pond and create a wet-to-dry fly ash conversion system and pneumatic conveying system. This system would convey hazardous fly ash to a greenfield storage site located approximately a half a mile from the client’s power plant along a state highway. The project involved multiple challenges. The site was on a steep slope which needed to be developed into a usable area to construct three concrete storage silos, a service building, ancillary equipment, and storm water detention facilities. The site grading was further complicated by the fact that storm water runoff in contact with fly ash is hazardous and cannot be released into the environment.
In a collaborative effort with a process equipment supplier and the project’s construction contractor, Salas O’Brien designed a cost-effective greenfield site development plan and arranged the new equipment at the plant to minimize disruptions to operations. Site grading was designed to level the site and provide intermediate working “benches” for pile driving equipment, while minimizing earthwork costs. To stabilize the existing slope, Salas O’Brien designed a soldier pile retaining wall with concrete panels and tie back rods. Above and below ground utility routing corridors were developed to minimize support structure and earthwork, while providing sufficient access for maintenance. Working with the State Division of Highways, Salas O’Brien coordinated permits for roadway crossings and work within public right of way. The storm drainage design provided for collection of contact water in a sump so that it could be pumped back to the plant for treatment, while non-contact water was directed to a storm water detention pond with a valve outlet and liner system.
As required by federal regulations, Salas O’Brien developed the storm water pollution prevention plan for construction permitting and assisted the utility with revisions to their NPDES storm water permits to incorporate the project. When the project concluded, the utility company became compliant with the updated federal regulations.