UST Remediation LNAPL Multiphase System

A multi­phase extraction system was designed to address an extensive LNAPL plume spanning multiple off-site properties to dewater the upper low-permeability zone and allow product recovery and vapor extraction in the sand units where the NAPL was trapped. Based on extensive aquifer testing and site characterization, a system of six dual phase (liquid and vapor) wells were installed and piped to a treatment system with an oil/water separator for LNAPL removal and an air stripper for water treatment. A waste water discharge permit with continuous remote monitoring was approved by the local POTW. The system was effective in removing all mobile NAPL and reducing groundwater concentrations of petroleum hydrocarbons.