Laserfiche WebLink
1 .1 <br /> C. Alternative No 3• Groundwater Extraction From Influent Trench 2, with Treatment <br /> and Discharge <br /> Groundwater containing VOCs would continue to be extracted from Trench 2 and <br /> treated using the existing air stripper. Remedial ob;ectives would be achieved <br /> through the active removal of VOC mass from groundwrter. The period of time <br /> to achieve VOC reduction would be approximately 8 years, based on observed <br /> trends. Total present worth is estimated at$477,550. <br /> d. Alternative No. 4. Groundwater Extraction From Influent Trench 2 and Well E-139 <br /> with Treatment and Discharge <br /> Well E-13 would be converted into an extraction well to remove VOC <br /> contaminated groundwater from this area. Groundwater containing VOCs would <br /> be extracted from Trench 2 and Well E-13, and treated using the existing air <br /> stripper. Remedial objectives would be achieved through the active removal of <br /> VOC mass from groundwater. The period of time to achieve VOC reduction <br /> would be approximately 5 years, based on observed trends. Total present worth <br /> is estimated at$426,600. <br /> 23. Varian's proposed final remediation plan (alternative 2) consists of. <br /> a. Termination of groundwater extraction pumping and placing the treatment system on <br /> standby status. <br /> b. Execution of deed restrictions for the property. <br /> c. Implementation of a quarterly sampling schedule with quarterly reporting to the <br /> Board for two years <br /> d Implementation of contingency procedures if certain criteria are exceeded. <br /> BASIS FOR CLEANUP STANDARDS <br /> 24 The Board establishes the overall cleanup level for a waterbody based upon the most sensitive <br /> beneficial use identified. In all cases, the Board first considers high quality g q y or naturally occurring <br /> "background" concentration objectives as the cleanup levels for polluted groundwater with a <br /> beneficial use of municipal and domestic supply, such as at this <br /> Site. If background concentrations <br /> cannot be achieved, cleanup levels are normally set no higher than• <br /> a Maximum Contaminant Levels (MCLS), or where MCLs have not been adopted, <br /> other valid technical data supporting maintenance of the beneficial use (i e , adopted <br /> Secondary Maximum Contaminant Levels, etc ), or, <br /> b Amore stringent level (below MCLs) based upon a Site specific risk assessment, or, <br /> c At a level lover than MCLs that i,, technically and economically feasible <br /> 5 <br />