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Z7A <br /> S S O CLI A T E S I N C <br /> concentrations have reduced to levels acceptable to the regulatory agencies or an apparent <br /> decreasing trend is evident, a closure plan will be submitted Well destruction permits <br />' would be obtained from the appropriate agencies and the wells would be destroyed by <br /> overdrilling the well casing and sand pack and pressure grouting the boring to the surface <br /> when concentrations have been reduced to an acceptable level <br /> ♦ Criterion 8 <br />' Since minimal activity would be conducted at the site, the impact on the community would <br /> be very minor and not disruptive to the businesses located on the site and nearby However, <br /> the rate of reduction of petroleum hydrocarbons in groundwater and soil concentrations <br />' does not appear to be acceptable to the regulatory agency <br /> 6 2 Groundwater Extraction with Soil Vapor Extraction <br /> ♦ Criterion I <br /> This alternative has minimal health-based risks Following treatment extracted <br /> groundwater is discharged to the sanitary sewer via a closed system and petroleum <br /> hydrocarbons are removed from extracted vapor prior to release to the atmosphere <br /> eliminating the risk of exposure to humans Groundwater would be monitored periodically <br /> to ensure that levels of petroleum hydrocarbons do not exceed allowable levels and to <br /> ensure that reduction is occurring The potential fire or explosion hazard is minimal with a <br /> properly designed system and regularly scheduled monitoring and maintenance <br /> ♦ Criterion 2 <br /> Groundwater extraction with vapor extraction would reduce the level of toxicity, mobility <br /> and volume of contaminants in the soil and groundwater to levels acceptable to regulatory <br /> agencies Previous pilot testing indicated that the vapor extraction portion of this is a <br /> feasible alternative for remediation of the site <br /> ♦ Criterion 3 <br />' This alternative can be implemented within regulatory guidelines <br /> ♦ Criterion 4 <br />' The groundwater extraction with soil vapor extraction remediation alternative would require <br /> the performance of a groundwater extraction pilot test to evaluate if this is an effective <br /> remedial option If groundwater extraction was determined to be a feasible option, this <br /> 1 method would require the installation of additional vapor extraction wells, and groundwater <br /> and soil extraction equipment Pilot testing indicates that extracted groundwater would <br /> have to be treated prior to being discharged to the sanitary sewer A thermal oxidizing unit <br /> or catalytic oxidizing unit can be used initially for the treatment of off-gases but may be <br /> changed to vapor-phase carbon after concentrations are reduced to levels acceptable to the <br />' regulatory agencies Additional costs to the client would be incurred for permitting, leasing, <br /> W 1625961reportslpdotcap doe 11 <br />