Reactive barriers

A permeable reactive barrier (PRB) is defined as an in situ method for remediating contaminated groundwater that combines a passive chemical or biological treatment zone with subsurface fluid flow management. Treatment media may include zero-valent iron, chelators, sorbents, and microbes to address a wide variety of groundwater contaminants, such as chlorinated solvents, other organics,... 

Natural organic matter Nonpurgeable organic carbon Parts per million by volume Permeable reactive barriers Polyvinyl chloride... 

U.S. EPA. Cost Analyses for Selected Groundwater Clean-up Projects Pump-and-Treat Systems and Permeable Reactive Barriers, EPA 542-R-00-013, United States Environmental Protection Agency, Washington, DC, February 2001. 

Gavaskar, A., Gupta, N., Sass, B., Janosy, R., and Hicks, J., Design Guidance for Application of Permeable Reactive Barriers for Groundwater Remediation, Prepared for US Air Force, Air Force Research Laboratory, March 2000. 

Interstate Technology and Regulatory Council (ITRC), Regulatory Guidance for Permeable Reactive Barriers Designed to Remediate Chlorinated Solvents, December 1999. 

U.S. EPA, Economic Analysis of the Implementation of Permeable Reactive Barriers for Remediation of Contaminated Ground Water, EPA/600/R-02/034, National Risk Management Research Laboratory, United States Environmental Protection Agency, Ada, OK, June 2002. 

The use of nanoscale materials in the dean-up of hazardous waste sites is termed nanoremediation. Remediation of soil contaminated with pentachloro phenol using NZVI was studied [198]. In a separate study, soils contaminated with polychlorinated biphenyls was treated using iron nanopartides [194], NZVI and iron oxide have been suggested to be used as a colloidal reactive barrier for in situ groundwater remediation due to its strong and spedfic interactions with Pb and As compounds [199]. 

Kanel, S.R., Greneche, J.M. and Choi, H. (2006) ArsenicfV) removal from groundwater using nano scale zero-valent iron as a colloidal reactive barrier material. Environmental Science and Technology, 40, 2045—2050. 

In situ reactive barriers Treat contaminated water as it passes through a physical barrier containing reactive chemicals, organisms, or activated carbon Site specific Slow process... 

Figure 3. Reactive Zone or Permeable Reactive Barrier to treat a contaminant plume in- situ.

Nonadsorptive retention of contaminants can also be beneficial. For example, oil droplets in the subsurface are effective in developing a reactive layer or decreasing the permeability of a sandy porous medium. Coulibaly and Borden (2004) describe laboratory and field studies where edible oils were successfully injected into the subsurface, as part of an in-situ permeable reactive barrier. The oil used in the experiment was injected in the subsurface either as a nonaqueous phase liquid (NAPL) or as an oil-in-water emulsion. The oil-in-water emulsion can be distributed through sands without excessive pressure buildup, contrary to NAPL injection, which requires introduction to the subsurface by high pressure. 

G.K (1999) Biogeochemical dynamics in zero-valent iron columns Implications for permeable reactive barriers. Environ. Sd. Tedm. 33 21709-2177 Gu, X.Y. Hsu, P.H. (1987) Hydrolytic formation of submicron iron(III) oxides from diluted ferric nitrate solutions. Soil Sd. Soc. Am. J. 51 469-474... 

T0490 M4 Environmental, L.P., Catalytic Extraction Process T0494 ManTech Environmental Corporation, CleanOX Process T0498 Matrix Photocatalytic, Inc., Ti02 Photocatalytic Treatment System T0509 Metal-Based Permeable Reactive Barriers—General... 

T0509 Metal-Based Permeable Reactive Barriers—General... 

T0601 Permeable Reactive Barriers (PRBs)—General... 

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