Field-Scale Trial of Sodium Persulfate for Treatment of MGP Residuals


Field-Scale Trial of Sodium Persulfate for Treatment of MGP Residuals

Andrew P. Brey, P.G. (Geosyntec Consultants, Inc.)
Neil R. Thomson (University of Waterloo)



Andrew P. Brey, P.G.

Geosyntec Consultants, Inc.

Speaker Bio:

Mr. Brey is a licensed Professional Geologist with more than 18 years of professional experience in the environmental remediation industry. He currently maintains a practice in Geosyntec Consultants Tampa, Florida office. He has directed MGP and chlorinated solvent assessment activities for various utility and industrial clients in the northeast U.S., Florida and Carolinas. In this capacity, project elements have included technical support on groundwater delineation, natural attenuation geochemistry and contaminant source forensic identification. His recent primary project experience includes detailed investigation and feasibility study of MGP sites and their associated surface-soil, subsurface-soil, and dissolved-phase groundwater plumes. He has put special emphasis on investigations of deeper (i.e., greater than 100 feet below land surface) impacted carbonate/limestone aquifers and development of conceptual site models (CSMs) in order to effectively evaluate remedial options, meet site assessment requirements and to provide data for cost allocations purposes. Mr. Brey has successfully implemented and managed RI/FS projects under USEPA Region 4 CERCLA consent order programs. He also has significant experience managing projects and negotiating outcomes under State of Florida waste cleanup regulatory programs.


Remediation of sites contaminated with non-aqueous phase liquids (NAPLs) such as manufactured gas plant (MGP) residuals or “coal tars” are problematic and hence a variety of technologies have been developed that enhance the rate of mass removal, which is vital to attain site restoration. Chemical oxidation has been touted as a potential silver bullet to deal with MGP residuals and NAPLs; however, the science-base is lacking in peer-reviewed scientific or engineering literature to support its use in full-scale applications. Geosyntec, in conjunction with University of Waterloo researchers, is currently performing a field-scale trial at a former MGP in Clearwater, Florida to evaluate the use of sodium persulfate to treat a mass of residual NAPL. The focus of the project research is to perform a multi-year pilot-scale evaluation of the ability of a chemical oxidant (sodium persulfate) to treat the source and remaining dissolved phase groundwater plume. The Site source and plume are located in a well-sorted, unconfined sandy aquifer. Multi-level sampling grids were installed within the source area and downgradient of the source area and have been monitored at regular intervals since 2011 to establish baseline groundwater conditions. Additionally, laboratory treatability evaluations (oxidant demand/interaction, aqueous and slurry) have been completed by the University of Waterloo. During 2015, the field experimental trial was performed utilizing two injection events of base-catalyzed persulfate within the target treatment zone (TTZ). Dissolved phase concentrations, contaminant mass in the TTZ and mass discharge across the downgradient multi-level sampling grid have been monitored and evaluated to assess treatment performance. The presentation will discuss the conceptual Site model, treatment system design, and system monitoring and performance results to date (2017).


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