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Mt. Robert Garcia • - 2 - • 8 July 2005 <br /> 4. After recovery of the bulk of the SPH,Leprino will evaluate soil venting and other bioremediation <br /> techniques to mitigate remaining TPHd in the soil and groundwater. Because SPH recovery may take <br /> several years to complete, Leprino proposes evaluating available technologies at that time to take <br /> advantage of best current technology. <br /> 5. Monitoring and site closure. <br /> a. Leprino is conducting groundwater monitoring under Monitoring and Reporting Program (MRP) <br /> No. R5-2003-0808. Leprino proposes amending this MRP to focus on documenting remediation <br /> progress. <br /> b. Leprino proposes general remediation goals of removing as much SPH as reasonably practical <br /> and demonstrating that residual diesel concentrations in the groundwater have declined to acceptable <br /> levels. <br /> After achievement of these goals, Leprino will petition the Regional Board to deactivate the remediation <br /> systems and ultimately grant a no-further-action declaration for the site. <br /> Comments <br /> 1. Regional Board staff concur with enhancements to recover as much SPH as possible from the soil <br /> and groundwater, therefore we concur with the first three phases of work proposed by Leprino. <br /> However, the Cleanup Plan only provides the general locations for the.proposed new extraction and <br /> monitoring wells. The final locations are to be chosen after the site assessment work is complete. The <br /> locations will be chosen based on permeability of the soils assessed by the boreholes and thickness of <br /> SPH on the water table. The proposed locations to the wells,and any supporting data such as boring <br /> logs,needs to be submitted to Regional Board staff for our concurrence prior to installation of the wells. <br /> 2. Leprino proposes evaluating current technologies for remediation of adsorbed TPHd from the soil <br /> and remaining dissolved-phase TPHd after recovery of all practical SPH has been achieved, as defined <br /> by remaining SPH in wells of 0.1 feet or less. Because Leprino proposes evaluating current technologies <br /> and proposing further remediation in the future, the Cleanup Plan as submitted is essentially an Interim <br /> Cleanup Plan. Regional Board staff concur with this approach. <br /> 3. The Cleanup Plan does not address the downgradient plume. Leprino needs to show that the plume <br /> is stable and that pollutant concentrations are decreasing. <br /> 4. Initially, all newly installed wells will be covered by the existing MRP. Regional Board staff concur <br /> with evaluating the MRP for its appropriateness after installation of the enhanced recovery features of <br /> the interim cleanup plan is complete. After all enhancements and adjustments to the product recovery <br /> system are complete, Leprino should submit their recommendations for revisions to the MRP. <br /> Downgradient wells also need to be sampled for parameters that will demonstrate that intrinsic <br /> bioremediation is taking place, such as dissolved oxygen, nitrates, sulfates and oxidation-reduction <br /> potential. <br /> 5. Regional Board staff concur with the general goals proposed in the Interim Cleanup Plan. Specific <br /> goals will be set in compliance with the Basin Plan and the Non-degradation Policy, that is, Leprino <br />