SCS Engineers provided comprehensive master planning and landfill engineering services for Portland’s solid-waste disposal facility, which consisted of two closed balefills and an active ashfill/balefill.
A 500-ton/day waste-to-energy facility serves greater Portland, Maine. The purpose of the master plan was to evaluate alternatives for expanding the ashfill/balefill, identify site constraints and provide budgetary estimates for the expansion alternatives. The master plan took into account the setback and buffer requirements in the Maine Department of Environmental Protection (MDEP), special liner requirements for an ashfill and local restrictions governing maximum allowable height of the landfill.
Sequential Fill Plans and Capacity Analysis
The ashfill/balefill was constructed on highly compressible marine clays. Detailed geotechnical analysis were completed on the existing ashfill configuration to establish criteria for sequencing the landfill filling activities in order to meet the minimum factors of safety for slope stability. A detailed fill sequence, including separate disposal areas and sequencing for bale and ash placement were prepared. A comprehensive geotechnical monitoring program was installed in order to monitor the performance of the landfill foundation soils.
Balefill Closure Design
SCS was tasked with preparing the design and permit application for the closure of its 40-acre balefill. The balefill consisted of two separate mounds, which had been partially closed with an interim cover system.