In August 2021, Hercules submitted an interim corrective measure (ICM) work plan for the shallow zone of the upper surficial aquifer for the Stillhouse Control Room Area of the Brunswick facility. The purpose of this ICM is to reduce the mass of selected contaminants of potential concern (“COPCs”) in groundwater in the shallow zone of the upper surficial aquifer underlying the southern production area of the Brunswick facility near a building designated as the Stillhouse Control Room.
The ICM will utilize in situ chemical oxidation (“ISCO”) to achieve mass reduction of COPCs in groundwater and is one of multiple ICMs for groundwater being implemented at the Brunswick facility. ISCO involves destruction of organic contaminants by injecting an oxidant into the groundwater treatment zone through injection wells or probes. The oxidant then destroys organic contaminants through oxidizing those contaminants that come into contact with the oxidant. Effective use of ISCO in groundwater requires direct contact between organic contaminants and the oxidant for a complete oxidation reaction to occur. Oxidants that are commonly used for remediation of groundwater include permanganate, persulfate (often combined with activators), ozone, percarbonate, and peroxide (e.g., Fenton’s reagent and calcium peroxide). Certain oxidants can also be combined for enhanced effects.
In September 2021, Hercules submitted an ICM work plan for the deep zone of the upper surficial aquifer at the Brunswick facility. The purpose this ICM is to reduce the mass flux and concentrations of selected COPCs that are detected in elevated concentrations in groundwater in the deep zone of the upper surficial aquifer underlying the southeastern portion of main operational area of the Brunswick facility along west side of the U.S. Highway 17 corridor.
The ICM will utilize in situ bioremediation in the form of a biologically active permeable reactive barrier (referred to as a “biobarrier”) to achieve mass flux reductions of COPCs in groundwater. This ICM will specifically target methylene chloride and chloroform in the treatment area because these two COPCs represent the majority of the volatile organic compounds (“VOCs”) that have been detected in groundwater in the area of the proposed biobarrier. The biobarrier is one of multiple ICMs for groundwater being implemented at the Brunswick facility.