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• • 07/13/2016 <br /> C&S Cleaners Site Work Plan <br /> The RWQCB did not concur with that request(memorandum from Bill Brattain to Scott Seyfried dated <br /> July 6, 2015). As described in their memorandum, the RWQCB indicated that available options to <br /> achieve regulatory closure included sealing of the existing concrete slab as a mitigation measure, or <br /> collection of additional monitoring data. <br /> Meeting with RWQCB to Discuss Site Closure February 2016 <br /> Representatives of Robinhood Plaza, LLC met with RWQCB staff on February 24, 2016 to discuss recent <br /> monitoring data and potential regulatory pathways to achieve site closure. <br /> During the February 24 meeting, all parties agreed that installation of a passive sub-slab venting system <br /> in the immediate vicinity of the dry cleaning machine represented a potentially appropriate mitigation <br /> measure for the Site. The general approach discussed with the RWQCB staff during this meeting was to <br /> install perforated sub-slab vent pipe in the area of highest residual PCE concentrations,which will <br /> connect to a rooftop vent. Piping will also be installed to connect EX-1 to the rooftop vent for additional <br /> venting. <br /> This work plan presents the proposed methodology to install the sub-slab vent system prior to receiving <br /> regulatory closure. Proposed methodology to abandon the existing soil vapor extraction wells also is <br /> included. <br /> PROPOSED SCOPE OF WORK <br /> The following scope of work is proposed: <br /> Task 1. Abandon three of the four existing soil vapor extraction wells and all sub-slab monitoring points. <br /> The fourth soil vapor extraction well will be used as part of the sub-slab venting system (see <br /> Task 2). <br /> Task 2. Install a passive sub-slab venting system, including installation of sub-slab perforated vent piping, <br /> connection to existing EX-1, and installation of conveyance piping to connect to rooftop vent <br /> with wind turbine fan. <br /> Task 3. Submit closure documentation to the RWQCB. <br /> These tasks are presented in more detail in the following section. <br /> Task#1 Well Abandonment <br /> Existing soil vapor extraction wells EX-1 through EX-4 were installed under permit from the San Joaquin <br /> County Environmental Health Department (SJCEHD).Terraphase will obtain well abandonment permits <br /> from the SJCEHD and will complete abandonment in accordance with requirements as set forth the <br /> SJCEHD abandonment permits. Pending receipt of approval from SJCEHD, it is anticipated that the wells <br /> will be sealed by pouring grout into the well casing up to the grade of the existing concrete floor. -a-nan�p'r��n <br /> Construction logs for EX-1 through EX-4 are included as Appendix A for reference. All well abandonment <br /> work will be performed by a licensed C-57 contractor. <br /> Terraphase Engineering Inc. Page 3 of 5 <br />