ELECTROCHEMICAL PEROXIDATION (ECP) AN EXSITU/INSITU PROCESS TO DEGRADE GROUNDWATER CONTAMINANTS

摘要

In laboratory trials, Electrochemical Peroxidation (ECP) has been successfully used to degrade BTEX, fuel additives (MTBE and EDB), chlorinated solvents, and polychlorinated biphenyls (PCBs) in groundwater. Additionally, ECP can be used to simultaneously address mixed wastes by using iron hydroxide floc formed as a part of the reaction to sorb and remove aqueous phase trace metals. Pilot tests are planned for two gasoline spill sites during 2000 where traditional pump and treat methods have proven ineffectual because of groundwater chemistry and subsurface hydrologic conditions. Under suitable conditions, the ECP uses a three phased approach consisting of: 1) exsitu chemical oxidation; 2) insitu oxidation by reinjection of treated water with residual oxidants at the head of the plume; and 3) reestablishment of aerobic biodegradation by alteration of subsurface redox conditions. In the ECP process, dissolved iron is derived electrochemically, negating the need for ferrous salt addition and dilute hydrogen peroxide (<300 mg/L) is incrementally added to maximize oxidation efficiency. In this approach, safety and environmental concerns accompanying the use of highly concentrated solutions are eliminated. In this paper, laboratory and a pilot scale demonstration of the ECP technology is discussed as well as the geological and geochemical considerations of the planned pilot-scale applications of the process are presented.