Everett, Massachusetts
The FCTPF Site encompasses 10 acres of the Island End River and 800 linear feet of river waterfront and was formerly a tidal marsh. The FCTPF Site had been used from the early 1900s through the 1950s by several coal-tar processing and gasification facilities. During this time, crude coal tar from the gasification plant was brought to the plant where it was stored until processed. Contaminants of concern associated with the coal-tar processing operations included PAHs, NAPLs, and DNAPLs.
Sevenson’s SOW included construction of an in-water low-permeability steel sheet-pile Confined Disposal Facility (CDF); mechanical dredging of approximately 70,000 CY of contaminated sediment; solidification and stabilization of approximately 50,000 CY of sediment within the footprint of the CDF; and construction of a 24-in., steel-reinforced concrete cap over the CDF. Sevenson utilized a PC400 excavator with an ALLU attachment and a PC400 long-front excavator with a bucket to mix the material within the CDF. Portland cement was mixed in our on-site batch plant and slurried in at 10% within the confines of the CDF.