WORK PLANS - Laserfiche WebLink

Home Browse Search

C\TATC A S S O C I A T E S I N C Soil Vapor Extraction Test Petroleum impacted soil and groundwater can often be remediated using vapor extraction techniques. Vapor extraction of petroleum hydrocarbon impacted soil and groundwater utilizes the fact that some petroleum hydrocarbon constituents can be volatilized or changed from the solid or liquid phase to the vapor phase at normal temperatures. The movement of air through the soil and groundwater, which is accomplished by extracting air from the subsurface through vapor extraction wells, facilitates the volatilization of contaminants to the vapor phase. These contaminants are then removed from the soil and groundwater by extracting the vapor with the petroleum hydrocarbons from the subsurface through vapor extraction wells and subsequently treating the vapor. ATC will perform a vapor extraction test (VET) to collect site specific data relative to vapor extraction from the subsurface and evaluate the feasibility of vapor extraction as a remedial alternative. The results of the pilot test will help to determine the effective radius of influence, to select the optimum off-gas abatement process; and to develop engineering design criteria for the construction of a remediation system at the subject site. Soil Vapor Extraction Pilot Testing Equipment The equipment that will be used during the VET consists of an internal combustion (IC) engine, a 5 horsepower blower, instrumentation for measuring air flow, air velocity, air pressure and air temperature, PVC piping, fittings, wellhead connections, a portable organic vapor analyzer, and air sampling apparatus. ATC will utilize the three new vapor wells to conduct the pilot testing. Long Term Vapor Extraction Test A VET will be conducted utilizing vapor wells to determine the feasibility of vapor extraction to remove contaminants in the soil. The pilot test will consist of one long term VET and two short term VET on the second day. The long term VET will be performed by applying a vacuum on one of the new vapor wells utilizing an IC engine for approximately six to eight hours or until subsurface conditions stabilize. The remaining two vapor wells will be used as observation wells. During the test, field personnel will measure flow rates, applied vacuum on the test well, induced vacuum in observation wells, pressure, and temperature. The extraction flow rate will be adjusted until the maximum flow rate and applied vacuum can be determined. Two influent vapor samples will be collected from the vapor extraction well for laboratory analysis of TPHg, BTEX, and MTBE. One vapor sample will be collected at the beginning of the test and one vapor sample will be collected at the end of the test. Also, an effluent vapor sample will be collected to determine destruction efficiency of the IC engine. Vapor samples will be analyzed for TPHg, BTEX, and fuel oxygenates by EPA method TO-14. w:\14885\workplans\wkpin2OO5.doc 5