Accession Number:

ADA604026

Title:

Electrically Induced Redox Barriers for Treatment of Groundwater

Descriptive Note:

Final rept. addendum

Corporate Author:

COLORADO STATE UNIV FORT COLLINS

Report Date:

2008-12-01

Pagination or Media Count:

19.0

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.

Subject Categories:

  • Organic Chemistry
  • Electrical and Electronic Equipment
  • Water Pollution and Control

Distribution Statement:

APPROVED FOR PUBLIC RELEASE