MULTIPLE TECHNOLOGIES OPTIMIZE REMEDIATION
New Franklin Laundry retained S. W. Cole Engineering, Inc. to assist in the assessment, remediation, and environmental closure of a former dry cleaning site. Previous investigations by others had found tetrachloroethylene (a.k.a., perchloroethylene, PCE) in soils at the site and in vapors in homes adjacent to the site. Working with New Franklin Laundry, the Environmental Protection Agency, the Maine Department of Environmental Protection, the City of Bangor and other consultants, we developed a plan to evaluate the extent of the problem, define the most likely sources of PCE and implement a plan using multiple technologies to remediate the site. From our initial involvement in August 2003, the project progressed through investigation, pilot testing and construction of remediation technologies, with full implementation of the remediation plan occurring in September of 2004.

MECHANICALLY STABILIZED EARTH WALL WITH EPS GEOFOAM CORE
S. W. Cole Engineering, Inc. was retained to design a 25-foot high, double-sided, mechanically-stabilized earthen (MSE) wall across a drainage gully that was underlain by soft compressible marine clays. The purpose of the wall was to provide support to construct new utilities and a new road associated with expansion of the Topsham Fair Mall commercial/retail subdivision.
It was imperative that the design of the MSE wall provide for a stable structure. In fact, the tolerable differential settlement for the wall was only 1-inch per 100-feet. This restriction on settlement was required both to control cracking of the concrete masonry unit (CMU) facing and to ensure performance of the sanitary sewer utility to be installed. Controlling post-construction settlement of the sanitary sewer utility was critical in order to prevent blockage of the sewer line, as the designed slope of the pipe was near the minimum feasible. The weight of the proposed structure was limited by the underlying soft clays.
To achieve the requirements outlined above, S. W. Cole Engineering, Inc. designed a MSE wall with a 10-foot thick EPS geofoam core sandwiched between 5-feet of sand and gravel fill below and 10-feet of sand and gravel fill above. Geofoam is a lightweight material often used in fill applications where a lightweight material is required to reduce stresses on underlying soils or to reduce lateral pressures. EPS (expanded polystyrene) geofoam is a closed-cell material that is about 98% air by volume and is only about 1% to 2% as dense as typical soil fill materials. The material is dimensioned in 4-foot by 8-foot by 25-inch tall billets or blocks.