Eliot Cooper

Superfund Pilot Test Results from a Mixed PFAS and Chromium Plume Using Colloidal Carbon and Base Activated Sodium Dithionite

Eliot Cooper, Vice President, Technology and Business Development, Cascade Environmental, LLC

Background:

Metal platers have been identified as a known source of PFAS contamination, with projected remediation costs of over $1 billion over the next 10 years (Environmental Business Journal). To mitigate Cr+6 exposure to plating bath operators, PFAS was used in vapor suppression systems.  As with many older industrial operations now under Superfund, PFAS and Cr+6 made their way into soils and groundwater.  

Overview:

  Lane Plating, Dallas, TX, is a former electroplating facility that conducted chrome electroplating for approximately 90 years up until 2015. Operations ceased in 2015 with numerous violations, investigations, and bankruptcy. In addition to a soil removal interim action, EPA has initiated pilot studies to finalize their remedy for groundwater remediation.    Cascade was tasked with selecting chemistries and injection approaches for pilot testing to treat both CR+6 and PFAS.  While we have treated Cr+6 by chemical reduction at numerous sites across the U.S., and have developed a colloidal carbon for PFAS sequestration, we looked at one of our other colloidal carbon formulations for chlorinated solvents.  This formulation is a combination of colloidal carbon and base activated sodium dithionite. We saw no reason why this formulation wouldn’t reduce Cr+6 and at the same time the colloidal carbon could sequester PFAS.    A pilot test was conducted during July 2024 to evaluate the efficacy of this combined remedy. Cascade will present the design considerations for the pilot test, injection approach and logs, and post injection groundwater results for Cr+6 and PFAS (primarily PFOS and PFHxS).

Conclusions/implications: 

Based on these pilot test results, it appears that colloidal carbon combined with base activated sodium dithionite, is a viable in situ treatment option for these dual contaminants.        

Mr. Cooper was a team member on numerous ITRC teams including the most recent Injection Optimization and Advanced Site Characterization teams. Mr. Cooper was a technical advisor on a SERDP/ESTCP project developing injection models for high volume applications of reagents including emulsified oils, chemical oxidants, and reductants. Mr. Cooper has worked in all aspects of industry including regulatory (EPA), consulting (KPMG), and industry (Amoco Oil). He has also presented platform presentations and learning labs at Battelle and other conferences highlighting industry best practices and technologies. Most Recently, Mr. Cooper has developed a new in situ chemistry line of products including colloidal carbon and colloidal ZVI for solvents, petroleum, CCR, and PFAS. Coupled with these chemistries, Mr. Cooper has developed new automated injection technology to enhance their in situ performance.