In Situ Catalytic Groundwater Treatment Using Palladium Catalysts and Horizontal Flow Treatment Wells
Abstract
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 mg/L) 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2007
- Accession Number
- ADA523484
Entities
Organizations
- Naval Facilities Engineering Service Center