EFR® has been implemented in a wide range of hydrogeologic regions throughout the United States(37 states)and Puerto Rico and is an innovative and cost effective alternative for the removal of volatile organic compounds (VOCs) from the subsurface. The EFR® process is best described as a mobile version of dual-phase or multi-phase extraction (DPE/MPE) and is represented in Figure 1. The greatest benefits of the EFR® process, as well as DPE/MPE technologies, is the ability to simultaneously treat all phases of VOCs while also addressing the entire impacted (unsaturated and saturated) soil column.

EFR® is a mobile system that is particularly effective in the removal of free product (e.g. gasoline and diesel). EFR® utilizes high vacuums (with vacuum pumps rated at a maximum of 27 inches of mercury) and high flow rates simultaneously connected to as many as eight monitoring or recovery wells. EFR® is normally conducted for an eight hour period per event. As much as 2,500 equivalent gallons of gasoline or diesel have been removed during a single eight hour EFR® extraction event.

Figure 1. Generalized Schematic of the EFR® Process

EFR® simultaneously removes vapors, free product, and groundwater from the subsurface. It volatilizes adsorbed and free phase VOCs through a process similar to vapor extraction, but with a much higher vacuum and radius of influence. EFR® is also very unique in that it can treat adsorbed phase VOCs existing within the "smear zone" (i.e. the zone of seasonal or climatic groundwater fluctuation) that act as a continuing source for dissolved phase VOCs. EFR® dewaters and exposes the smear zone to the effects of "high rate" soil vapor extraction. EFR® has also been well documented to be effective in the reduction in dissolved phase concentrations. Importantly, EFR® also introduces oxygen to the vadose and saturated zones, thereby enhancing aerobic biodegradation.

EFR® is an important tool, particularly for source removal. As such, it is an excellent compliment to risk based corrective action (RBCA) since source materials can be readily removed, thereby potentially allowing a risk based decision to then be rendered resulting in "monitoring only," no further action (NFA), or a reduced size remediation system. EFR® also possesses obvious applications at sites where rapid remediation is necessary (e.g. real estate transfers, off-site plume migration, emergency response, etc.) and can be introduced at any time during the "life cycle" of a site. EFR® is a "pay as you go" remediation method that involves no capital cost investment or operation and maintenance (O&M).