Superfund Research Program
Controlled Release Polymer Structures of In Situ Chemical Oxidation of Contaminated groundwater
Project Leader: Alexis W. Carpenter
Grant Number: R41ES026916
Funding Period: Phase I: September 2016 – September 2017
The EPA estimates that one out of every four Americans lives within three miles of a hazardous waste site. Over 450,000 brownfield sites are awaiting remediation and 1,280 sites on the National Priorities List. Potential Responsible Parties or the Superfund program are tasked with remediating these sites, but insufficient funding and a growing number of sites have led to significant delays. The U.S. remediation market has been growing steadily since 2009, averaging 2-3% increases per year, and the global environmental remediation technology market is forecasted to expand to $80.5 billion in 2019. Clearly there is a societal need and market potential for innovative remediation technologies that decrease cost and increase efficacy. In Situ Chemical Oxidation (ISCO) is the fastest growing remediation technique as it is lower cost, more effective, and less disruptive than other methods. However, current ISCO methods require gaseous or liquid-form oxidizers that pose significant hazard to workers during transport and delivery and often require multiple injections, which increase cost and exposure risk. AxNano, in collaboration with North Carolina A&T, has developed Controlled Release Polymer Structures (CRPS) as a slow release ISCO technology that will transform the environmental remediation industry by: (1) mitigating exposure risk during deployment by encapsulating the reactive agents within a safe, easy to handle, solid matrix; and (2) allowing for efficient treatment of contaminated groundwater via sustained release of high doses of reactive agents with a single application. As part of this project, researchers are determining design parameters to enhance the efficacy of AxNano’s patented CRPS for ISCO remediation of contaminated groundwater. The CRPS is being optimized by maximizing the oxidative agent(s) loading while maintaining a stable solid structure. Proof-of-concept tests are being conducted under varied conditions (i.e., pH, temperature, and density) in dynamic flow column studies that mimic those present in the subsurface environment. Broad spectrum efficacy of the optimized CRPS to transform two classes of Superfund-relevant contaminants (i.e., chlorinated compounds and polyaromatic hydrocarbons), is also being tested over a range of concentrations to yield dose response curves. Collectively, the results of this project will be used to model the performance of these materials in realistic environments and guide planning of pilot scale field studies. The work also involves designing a plan for scale-up, manufacturing, and preparing for pilot field testing. Scale-up design, cost of manufacturing, and deployment strategies of this solid phase material compared to current liquid and gaseous ISCO remediation technologies will also be evaluated in order to determine the feasibility of transitioning this technology to a commercial product.