Electrically Induced Redox Barriers for Treatment of Groundwater
Abstract
ESTCP Project ER-0112 Electrically Induced Redox Barriers for Groundwater Treatment was completed in March, 2005. Two follow-up studies were conducted in 2004 and 2005: 1. Screening of Titanium-mixed Metal Oxide Electrodes for e-barriers (March, 2003-March, 2005) and 2. Extended operation of the e-barrier Field Demonstration (August, 2004 January, 2006) These studies were added to provide cost and performance information regarding alternate electrode materials for uses in future e-barrier applications, and to provide additional monitoring data regarding the cost and performance of e-barrier technology applied to trichloroethene (TCE) in groundwater. Results from the electrode studies indicated that titanium-mixed metal oxide mesh (Timmo) has potential lifespan of more than 25 years. Other cathode materials tested included stainless steel, graphite felt, iron foam, copper screen, and Ti-mmo that had been deployed as part of a field prototype e-barrier at Canadian Forces Base Borden, Ontario. In general, Ti-mmo electrodes outperformed all other options. Extended operation of the field demonstration at F.E. Warren Air Force Base (AFB) indicated an optimal voltage of 4.0 V applied potential resulting in sustained removal of TCE at 75 percent along the center transect and minimal formation of chloroform compared to observations at higher applied potential differences. A snow storm around day 650, followed by slow melting, appears to a have imposed an approximate order of magnitude drop in TCE concentrations at sampling points up and downgradient of the e-barrier. Subsequently, TCE concentrations rebounded. Our original hypothesis was that the steady drop in upgradient and downgradient TCE concentrations (days 650-1000) was related to e-barrier operations. Unfortunately, the rebound does not support this hypothesis. Analysis of soils show potential increases in total biomass and eukaryotes downgradient of the e-barrier.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2008
- Accession Number
- ADA604026
Entities
People
- Dave Gilbert
- Matthew Petersen
- Tom Sale
Organizations
- Colorado State University