Municipal solid waste landfills consist  largely of organic material that decomposes over time and can quickly settle 5–10 feet or more depending on the waste thickness, type, compaction, moisture content, and other factors. This is especially problematic when waste on the lower portions of the landfill side slopes settles to below permitted grades, making it difficult to fill to the permitted grades up slope. As landfill grades get higher, the loss in airspace increases exponentially. Landfill operators sometimes recover the lost airspace by refilling thin layers on the lower slopes of the landfill.

However, this filling process presents many operational challenges including stripping existing soil cover, controlling odors from the waste below the stripped area; maintaining operation of an existing GCCS; and placing, grading, and compacting waste in an area that may be inaccessible to current waste-filling operations. Personnel visited a landfill in Pennsylvania where aprogram allowed landfill owners/operators to implement a Settlement Accommodation Plan (SAP) for controlled waste filling above permitted waste grades to reduce the amount of airspace loss due to settlement. This inspired a conversation with the Ohio EPA on a potential SAP approval at the Franklin County Sanitary Landfill. The Ohio EPA eventually approved SWACO’s SAP making this the first landfill in Ohio with permission to fill waste above permitted grades. SWACO implemented the SAP in 2024 and continues to monitor the settlement of the overfill.

This presentation will focus on the technical process of obtaining regulatory approval, include data comparing the predicted and actual amount of settlement, and discuss the relationship between the landfill and Ohio EPA that allowed for approval of new operational criteria.