Permeable Reactive Barriers

PRBs are a technology used to mitigate the spread of contaminants. Reactive material is placed in the subsurface where a plume of contaminated groundwater must move through it as it flows. The treated water comes out the other side. The PRB is not a barrier to the water, but it is a barrier to the contaminant.

Introduction

A permeable reactive barrier (PRB) is a zone of reactive material that extends below the water table to intercept and treat contaminated groundwater. EPA researchers investigate the geochemical, hydrogeological, and microbiological factors that govern the performance and functioning of PRBs. Understanding these factors is necessary in order to predict the longevity of PRB systems, conduct economic analysis, and optimize this groundwater cleanup technology for a wide variety of hazardous compounds.

This research supports EPA by providing technical expertise on the application of PRBs at waste sites. Documents provide regulators with a scientific and economic framework for technology selection at impacted sites. Expertise and guidance include the following:

Long-term performance – A unique feature of the research program is that long-term (greater than 10 years) monitoring is performed at well-characterized sites.
Pilot-scale PRBs – Projects evaluate applications of the PRB technology, such as untested reactive media or applications in complex hydrogeologic environments.
Basic processes research – EPA performs in-house studies of basic chemical, physical, and biological processes of importance to PRB systems. These efforts typically result from field projects where knowledge gaps are identified.

References and Products

EPA Published Reports

Field Application of a Permeable Reactive Barrier for Treatment of Arsenic in Ground Water (EPA/600/R-08/093) September 2008 – Abstract

Capstone Report on the Application, Monitoring, and Performance of Permeable Reactive Barriers for Ground-Water Remediation – Volume 2, Long-Term Monitoring of PRBs: Soil and Ground Water Sampling (EPA/600/R-03/045b) August 2003 – Abstract

Capstone Report on the Application, Monitoring, and Performance of Permeable Reactive Barriers for Ground Water Remediation – Volume 1, Performance Evaluations at Two Sites (EPA/600/R-03/045a) August 2003 – Abstract

This document provides detailed performance monitoring data on full-scale PRBs installed to treat contaminated groundwater at two different sites. It contains information needed by site managers and others who are faced with the need to remediate groundwater contaminated by chlorinated solvents, chromium, arsenic, nitrates, and other organic and inorganic compounds and who are considering the use of this cost-effective technology.

Journal Articles

Wilkin, R.T., Acree, S., Ross, R., Lee, T., Puls, R., and Woods, L. (2014). Fifteen-year assessment of a Permeable Reactive Barrier for treatment of chromate and trichloroethylene in groundwater. Science of the Total Environment, v. 468-469, p. 186-194.

Ludwig, R.D., Smyth, D., Blowes, D.W., Spink, L.E., Wilkin, R.T., Jewett, D.J., and Wisener, C.J. (2009). “Treatment of Arsenic, Heavy Metals, and Acidity Using a Mixed ZVI-Compost PRB.” Environmental Science and Technology, 43: 1979–1976.

Wilkin, R.T., S.D. Acree, R.R. Ross, D.G. Beak, and T.R. Lee. (2009). “Performance of a Zero-Valent Iron Reactive Barrier for the Treatment of Arsenic in Groundwater: Part 1. Hydrogeochemical Studies.” Journal of Contaminant Hydrology, 106: 1–14.

He, Y., J.T. Wilson, and R.T. Wilkin. (2008). “Transformation of Reactive Iron Minerals in a Permeable Reactive Barrier (Biowall) Used to Treat TCE in Groundwater.” Environmental Science and Technology, 42: 6690–6696.

Su, C. and R.W. Puls (2007). “Removal of Added Nitrate in the Single, Binary, and Ternary Systems of Cotton Burr Compost, Zero-Valent Iron, and Sediment: Implications for Groundwater Nitrate Remediation Using Permeable Reactive Barriers.” Chemosphere, 67: 1653–1662.

Factsheets

US EPA. Richard Wilkin, Weaver, Jim and Jewett, David. (2013) "Performance Assessment of a Permeable Reactive Barrier for Ground Water - Remediation Fifteen Years after Installation." (PDF) Publication No. EPA/600/F-13/324.