Gowanus Canal Superfund Site. II: Stabilization/Solidification of MGP-Impacted Sediments

Abstract

The Gowanus Canal Superfund site is located in Brooklyn, New York. The sediment of the 2.9-km (1.8-mi) long canal is impacted at multiple locations by nonaqueous phase liquids (NAPLs) mainly from three historic manufactured gas plant (MGP) sites with measured NAPL saturations up to 50%. A stabilization/solidification (SS) treatability study was completed using 15 mix designs in a tiered testing suite that included unconfined compressive strength, hydraulic conductivity, and contaminant leach testing by equilibrium (as per U.S. EPA standard methods) and semidynamic leach methods, where semidynamic leach testing was modified with polydimethylsiloxane liners. Mix designs containing 5–10% (by dry weight) of a cement blend paired with 0.5% bentonite, or 1–4% organoclay added to wet NAPL-impacted sediments were characterized by unconfined compressive strength values greater and hydraulic condictivity values lower than 345 kPa (50 psi) and