Abstract
Previously, the authors have developed the concept of in-situ reduction of hexavalent chromium in contaminated groundwater, using various forms of active reagent delivery, based on site geohydrological conditions. While these approaches are highly successful and cost effective, in some cases, such active approaches may not be appropriate. Rather, it may be appropriate to limit the spread of chromium contamination by formation of permeable reactive barriers or reactive zones through the borehole placement of aqueous reductants. A passive approach, utilizing bore-hole placed reactive barriers and Monitored Natural Attenuation (MNA), offers real advantages for groundwater remediation, especially in situations involving groundwater in fractured or cavernous bedrock, where the water table is at great depth, or where on-going activities in the source area limit access for more active approaches. A geochemical reactive barrier was used at a South Australian timber preservation facility sited over a cavernous limestone. After remedial activities within the plume achieved significant reduction of the mobile chromium mass, the applicable regulatory agency authorized MNA for control of residual contamination. A phased approach has been utilized at a Central Valley, California timber preservation site, to develop data on the radial spread of reductant injection through diffusion, and the longevity of the effect of such injection, and a full-scale remedial approach designed, recognizing limitations on injection imposed by limited access. The paper discusses the requirements to demonstrate the effectiveness of MNA. Case histories of successful application of the integrated approach of passive reduction and MNA are presented, as a cost-effective and environmentally-protective means of accomplishing remediation of hexavalent chromium in groundwater.
© 2016 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Preface
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- Kinetics of Wet Oxidation Reactions
- Biodegradability Enhancement of Wastewater Containing 4-Chlorophenol by Means of Photo-Fenton
- Experimental and Modelling Approach for the Comparison of Fenton and Electro-Fenton Processes. Preliminary Results
- TiO2/C Photocatalyst Prepared by Ethanol Vapour Treatment of TiO(OH)2
- Effects of Carbon Coating on TinO2n-1 for Decomposition of Iminoctadine Triacetate in Aqueous Solution under Visible Light
- Hybrid Plasma-Catalyst System for the Removal of Trichloroethylene in Air
- Photocatalytic Oxidation of Emerging Contaminants: Kinetics and Pathways for Photocatalytic Oxidation of Pharmaceutical Compounds
- Photocatalytic Degradation of four Textile Azo Dyes in Aqueous TiO2 Suspensions: Practical Outcomes and Revisited Pathways
- Decolouration of Dye Solutions Using Photoelectrocatalysis and Photocatalysis
- Aged Raw Landfill Leachate: Membrane Fractionation, H2O2/UV Treatment and Molecular Size Distribution Analysis
- Electrochemical Treatment of Trace Endocrine Disrupting Chemicals with a Three-Dimensional Electrode System
- Semiconductor Mediated Photocatalysed Degradation of a Pesticide Derivative, Acephate in Aqueous Suspensions of Titanium Dioxide
- Hexavalent Chromium Remediation by Bore-Hole Placed Reduction Barriers and Monitored Natural Attenuation
Articles in the same Issue
- Preface
- Removal of PAHs from Creosote Oil Contaminated Soil by Addition of Concentrated H2O2 and Biodegradation
- Kinetics of Wet Oxidation Reactions
- Biodegradability Enhancement of Wastewater Containing 4-Chlorophenol by Means of Photo-Fenton
- Experimental and Modelling Approach for the Comparison of Fenton and Electro-Fenton Processes. Preliminary Results
- TiO2/C Photocatalyst Prepared by Ethanol Vapour Treatment of TiO(OH)2
- Effects of Carbon Coating on TinO2n-1 for Decomposition of Iminoctadine Triacetate in Aqueous Solution under Visible Light
- Hybrid Plasma-Catalyst System for the Removal of Trichloroethylene in Air
- Photocatalytic Oxidation of Emerging Contaminants: Kinetics and Pathways for Photocatalytic Oxidation of Pharmaceutical Compounds
- Photocatalytic Degradation of four Textile Azo Dyes in Aqueous TiO2 Suspensions: Practical Outcomes and Revisited Pathways
- Decolouration of Dye Solutions Using Photoelectrocatalysis and Photocatalysis
- Aged Raw Landfill Leachate: Membrane Fractionation, H2O2/UV Treatment and Molecular Size Distribution Analysis
- Electrochemical Treatment of Trace Endocrine Disrupting Chemicals with a Three-Dimensional Electrode System
- Semiconductor Mediated Photocatalysed Degradation of a Pesticide Derivative, Acephate in Aqueous Suspensions of Titanium Dioxide
- Hexavalent Chromium Remediation by Bore-Hole Placed Reduction Barriers and Monitored Natural Attenuation