Patrick Singer

Colloidal Activated Carbon Used to Reduce PFAS Risk in Groundwater at Airports Worldwide: A Multiple Site Review

Patrick Singer, Southeast District Manager, REGENESIS

Groundwater contamination by chlorinated solvents poses significant environmental challenges, primarily in the speed in efficacy needed for projects such as property redevelopments.  Regenesis has engineered a suite of technically advanced colloidal technologies based on activated carbon, sulfidated zero-valent iron (ZVI), and solid organics. These patented technologies offer a groundbreaking approach to accelerate effective chlorinated solvent remediation, characterized by co-mixability, superior distribution properties, high reaction speeds, and longevity.  These amendments' co-application, flexibility and tunability enable precise chemical redox control. Colloidal activated carbon (CAC) immediately absorbs contaminants and prevents plume movement, effectively increasing residence time for action by other chemistries. Additionally, the prolonged reactive performance of Regenesis colloidal ZVI and colloidal organics can ‘dial in’ biotic and abiotic reduction chemistries where performance matters, such as barriers near property boundaries, roadways, etc.   Historically, standard batch mixing and injection practices for in-situ remediation have faced challenges in vertical or horizontal dosing adjustments, limiting the flexibility of applying colloidal amendments. To address this, Regenesis pioneered the world’s first in situ inline injection system, commercially known as IBIS, designed for highly flexible and precise dosing, with the ability to adjust point-by-point. This new system improves granular dosing of colloidal amendments while improving delivery efficiency by over 20% and reducing overall application costs.  A pilot-scale permeable reactive barrier (PRB) using PlumeStop and S-MicroZVI was implemented to treat a fast-moving, high-concentration TCE, cis-1,2DCE, and VC plume. Within a month, the highest concentrations were reduced by 98%, and the single injection event maintained at least 99% reductions of chlorinated ethenes for 3.5 years in performance wells. Following extended post-application monitoring, full-scale implementation of colloidal carbon, ZVI, and donor will be performed in the Fall 2024 using the new IBIS system, with the most recent data to be shared in this presentation.  

Patrick Singer has more than 3 years of experience in environmental remediation, starting with REGENESIS as a Project Supervisor with REGENESIS Remediation Services. He provides support and management to soil and groundwater remediation through the utilization of chemical reduction, chemical oxidation, sorption, and enhanced bioremediation methods throughout the United States. Patrick has assisted in the design and implementation of complex remediation projects, including those with LNAPL, DNAPL, and PFAS contaminated sites. He currently works alongside professional geologists and engineers to implement innovative remedial strategies. Patrick is currently the Southeast District Technical Manager for REGENESIS, based in Atlanta, GA, and holds a B.S in Natural Resources from the University of Georgia.