B&N was part of a team that consolidated and capped a 105-acre landfill located at the former Lockbourne Air Force Base (AFB) near Columbus, Ohio. The project was the largest environmental contract issued by the Louisville (Kentucky) District of the U.S. Army Corps of Engineers to date.
For decades, all waste generated at the base – from building construction materials to food scraps – was dumped over a 105-acre area of the site. Disposal activities occurred between 1951 and 1979 when environmental regulations were less stringent, so the landfill was never closed or lined properly. The landfill closure project was initiated in 2012 by the U.S. Army Corps of Engineers in coordination with Ohio Environmental Protection Agency (EPA).
B&N assisted throughout the project as a subconsultant to CAPE Environmental Management and provided environmental and landfill engineering services and expertise. Environmental Management Specialists completed the excavation and consolidation of the waste into a waste consolidation cell and final landfill cap.
Investigating the Unknown
It had been almost a decade since the last environmental site investigation at the former Lockbourne AFB. The client and project partners were concerned about unknown items that might be found amid the massive volume of solid waste, including unexploded ordnances and drums containing chemicals onsite. Before excavation and waste consolidation started, B&N led the site investigation that also provided a thorough overview of existing groundwater and surface water conditions. This data was used as a benchmark to check that the cleanup measures improved the water quality.
B&N's tasks included:
- Groundwater and surface water sampling
- Abandoning and installing monitoring wells
- Completing groundwater flow and fate and transport modeling
- Evaluating data by completing a risk assessment
- Assistance with wetlands delineation and mitigation
- Assessment of endangered species habitats
- Landfill engineering consultation
- Inspection of stormwater management
- Analyses of slope stability
Once the initial investigations were complete, the excavation and grading could start. The contractor had to cut down a large number of trees and vegetation that had grown over a majority of the disposal site to access and consolidate the waste underneath. B&N completed additional monitoring during construction to determine whether these activities impacted water quality. Finally, the landfill was capped with soils that inhibit surface water infiltration and minimize leachate generation.
Compliance and Post-Closure Guidance
B&N also served as the state solid waste regulatory compliance specialist on the project, responsible for helping to ensure that Ohio regulations were met during landfill closure activities. The B&N team also provided guidance on state regulatory requirements for all post-closure management of the landfill. This included preparing a 30-year Long-Term Management Plan that totaled more than 3,900 pages of detailed information. The project was successfully completed in 2017.