In Situ Catalytic Groundwater Treatment Using Palladium Catalysts and Horizontal Flow Treatment Wells
NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
Pagination or Media Count:
The U.S. Environmental Protection Agency EPA estimated in 1996 that of 8,336 DoD sites needing cleanup, approximately 70 had contaminated groundwater, mostly from chlorinated solvents such as trichloroethylene TCE and tetrachloroethylene PCE. Because TCE and PCE are mobile and refractory in aquatic environments, there is significant need for efficient treatment methods. Palladium Pd catalyzed reductive dechlorination transforms chlorinated ethylenes and other VOCs into their respective saturated hydrocarbons or lesser chlorinated analogues. With hydrogen gas as the reductant, the process is selective requiring only small quantities of hydrogen to remove contaminants to below regulatory limits. For some VOCs the dechlorination reaction occurs rapidly, even in water under ambient temperature, pressure and pH. The process can be utilized to efficiently treat water contaminated with reactive chlorinated contaminants. A one-pass catalytic process has many advantages, mainly that contaminants are destroyed instead of being transferred to another medium e.g. air or activated carbon, thus avoiding generation of a secondary waste stream. The technology is particularly favorable for treating water contaminated with high concentrations 1 mgL of chlorinated ethylenes and is therefore suited for source control. The principal objectives of this evaluation were to 1 Demonstrate the efficacy of catalytic treatment for the destruction of chlorinated ethylenes in groundwater using Pd catalyst. 2 Optimize treatment efficiency. 3 Develop cost and performance data for full-scale application of the technology.
- Water Pollution and Control