American Electric Power (AEP) and Cardinal Operating Company (COC) are in the process of installing flue gas desulfurization (FGD) systems on Units 1 and 2 at the Cardinal Plant in Brilliant, Ohio in response to regulatory air emission requirements. The Cardinal Plant is a three-unit 1830 MW coal-fired generating station. The FGD systems are scheduled to be operation in late 2007.
The FGD systems will produce gypsum residual waste and purge stream solids. The residual material that cannot be utilized in off-site commercial operations will be placed in a Class III residual waste landfill (RWL). A primary AEP and COC objective is to locate the RWL as close to the Cardinal Plant as possible while meeting Ohio Administrative Code (OAC) siting criteria for such facilities.
Geosyntec's Scope of Services
Geosyntec's scope of services for the RWL began with a siting study that involved the screening of alternative potentialities with respect to OAC siting criteria, economics, capacity (including expansion potential), and construction, operation and maintenance challenges. When the alternatives were narrowed to two candidate sites, Geosyntec identified site data gaps and performed additional field investigations at each site. AEP then made a final site selection for the RWL based on Geosyntec's conceptual design work and economic analysis for each site. The selected RWL site is located on AEP property and situated partially within a closed fly ash reservoir containing more than 100 feet of fly ash, partially over a remnant mine spoil bench, and against a remnant mining highwall. The RWL location satisfied AEP and COC plant proximity needs and OAC siting criteria; however, the setting presents a number of technical and regulatory challenges.
As part of its support for the Permit-To-Install (PTI) application to OAC, Geosyntec performed detailed engineering analyses to evaluate factors of safety for the proposed RWL with respect to: hydrostatic uplift, static and seismic slope stability, and static and seismic liquefaction. Analyses were performed to evaluate the settlement potential of the RWL foundation. An essential element of our design incorporates an innovative pre-loading and settlement monitoring program for the portion of the RWL to be constructed over the closed fly ash reservoir. The pre-loading will be performed concurrently with development of the RWL in the area of the mine spoil bench and highwall using excavated on-site mine spoil.
Geosyntec's portion of the PTI application package included more than 40 design drawings, extensive geotechnical and hydrogeological investigation reports, a geotechnical stability analysis report, a construction and operations plan, a quality assurance/quality control plan, and a final closure/post-closure plan including closure and post-closure care cost estimates. Geosyntec has worked closely with AEP engineers and permitting specialists to integrate these deliverables with those being prepared by AEP to ensure a complete and consistent PTI application submittal to Ohio EPA. Due to the considerable technical and regulatory challenges of the site setting, AEP and Geosyntec have maintained regular communications with Ohio EPA throughout the design and PTI application preparation, and also during the agency's ongoing PTI review and approval process.
Geosyntec applied its engineering expertise to the considerable engineering and design challenges associated with developing the RWL on top of an existing fly ash reservoir. Working hand-in-hand, AEP and Geosyntec have developed a technically sound and economically feasible solution to managing residual waste from the planned Cardinal Plant Units 1 and 2 FGD process. The design was developed on an expedited schedule to meet stringent Ohio EPA regulatory requirements.