Ash Excavation and Processing to Recover Metals

Ash Excavation and Processing to Recover Metals

ecomaine Ash Landfill, South Portland, Maine


SME assisted ecomaine and its subcontractor RMP-EM LLC in preparing site excavation and development plans to systematically remove, process, and replace incinerator ash in the ecomaine ash landfill.

In developing this project, SME considered several existing site conditions and site sensitivities. The mined area had been filled and a plastic cover placed on the ash to allow diversion of clean surface water to run off the covered landfill area.

The excavation plan needed to sequence the removal and replacement of the cover to both limit the additional leachate generation and maintain the diversion of clean surface water runoff for the covered areas of the landfill. The site excavation plan also had to factor in the low strength soil conditions that underlie the landfill. This required designing the excavation and development plans with consideration to the stability of the foundation soils. The excavation plan prescribed a very specific sequencing plan for both excavating and then replacing the ash once it was processed.

Project Outcome and Value Added

SME prepared state and local permits for this project. These permits addressed siting issues such as visual impacts, traffic, noise, odor, dust, stormwater management, and erosion control. The application also described process design for removing, processing, stockpiling of recovered metals, and replacing the ash. SME worked with RMP-EM to develop a project layout that allowed all of these activities to occur within the existing landfill footprint, minimizing overall project impact to the surrounding site environs. This was beneficial in both the state and local permitting process, and allowed for a quick review and approval of the project.

Permits were received in a timely manner. The project was instituted and operated for several years. By removing and recycling the metals from the ash, ecomaine recaptured valuable air space for additional ash, extending the landfill life.