Location
Grand Rapids, Michigan
Start Date
15-5-2024 9:30 AM
End Date
15-5-2024 10:00 AM
Description
EPA’s Value Engineering Approach for Gypsum Stack Closure Authors Mr. Michael Ayers - United States - Watershed Geo Mr. Craig Zeller - United States - US EPA Abstract In February 2017, US EPA Region 4 assumed responsibility for water treatment and daily operations for an unlined and open 350-acre gypsum stack located in Pascagoula, Mississippi. The gypsum stack contains approximately 15M cubic yards of phosphogypsum with elevated levels of nutrients and acidic pH. To the immediate east of the facility is one of the most biologically productive estuarine ecosystems in the Gulf of Mexico region. An uncontrolled and untreated release of contact water or leachate from the stack could have catastrophic effects on the Gulf of Mexico and its ecosystem. As a result of these potential risks, the US EPA endeavored to close the gypsum stack as quickly, cost effectively and with minimal impact to the surrounding environment. The two primary closure systems were evaluated and included a soil‐protected geomembrane cover (Traditional Cap) and synthetic turf geomembrane cover (ClosureTurf®). A value engineering study was performed to assess construction costs, operation and maintenance (O&M), environmental impacts, and constructability and ultimately resulted in the selection and installation of ClosureTurf®. The presentation will provide the results of the EPA’s study, key lessons learned from design through installation and discussion of how these same criteria apply to CCR projects.
Document Type
Presentation
EPA’S Value Engineering Approach for Gypsum Stack Closure
Grand Rapids, Michigan
EPA’s Value Engineering Approach for Gypsum Stack Closure Authors Mr. Michael Ayers - United States - Watershed Geo Mr. Craig Zeller - United States - US EPA Abstract In February 2017, US EPA Region 4 assumed responsibility for water treatment and daily operations for an unlined and open 350-acre gypsum stack located in Pascagoula, Mississippi. The gypsum stack contains approximately 15M cubic yards of phosphogypsum with elevated levels of nutrients and acidic pH. To the immediate east of the facility is one of the most biologically productive estuarine ecosystems in the Gulf of Mexico region. An uncontrolled and untreated release of contact water or leachate from the stack could have catastrophic effects on the Gulf of Mexico and its ecosystem. As a result of these potential risks, the US EPA endeavored to close the gypsum stack as quickly, cost effectively and with minimal impact to the surrounding environment. The two primary closure systems were evaluated and included a soil‐protected geomembrane cover (Traditional Cap) and synthetic turf geomembrane cover (ClosureTurf®). A value engineering study was performed to assess construction costs, operation and maintenance (O&M), environmental impacts, and constructability and ultimately resulted in the selection and installation of ClosureTurf®. The presentation will provide the results of the EPA’s study, key lessons learned from design through installation and discussion of how these same criteria apply to CCR projects.
