Continued preparation of site for barrier installation

National Grid’s contractor and Project Team continued to plan for the composite 120-foot deep dense non-aqueous phase liquid (DNAPL) Migration Barrier Wall (i.e., jet grouted barrier) installation. The Contractor continued Phase 3 remediation construction activities at the Site. The contractor continued general maintenance of the Site and continued the assembly of the Jet Grout Plant system. The contractor continued the mobilization of personnel and equipment, and continued site preparation activities including the construction of the waste management facility (WMF) and repairs to the temporary fabric enclosure (i.e., tent). The WMF, which manages wastes (e.g., soils, cement mix and water) that are generated from jet grouting activities, will be operated inside the tent with an active Vapor Management System (VMS). All jet grouting wastes will be managed in accordance with NYSDEC approved procedures. The jet grouting contractor (JGC) and waste management and emergency response (WM/ER) contractors prepared pre-mobilization submittals and scheduled activities for the project. Attached is a photograph of the site preparation activities.

Repairing the tent

Maintenance of the imported backfill material (i.e., clean fill) stockpile covers and soil erosion and sediment control (SESC) measures continued. Odor and dust suppression activities were conducted, as necessary. National Grid’s consulting engineers continued to monitor the site activities with the community air monitoring program (CAMP) equipment.

During the period from October 17, 2011 through October 23, 2011, six fixed base CAMP units were in operation and measured total volatile organic compounds (TVOC) and particulates (PM10). Fifteen-minute averages for both TVOC and PM10 data remained in the Operational Condition. There were no elevated readings for TVOC or PM10 for this monitoring period. The Weekly Report that summarizes the CAMP data can be found as a separate tab in the Weekly Report Archive section.

For the week of October 24, 2011 through October 28, 2011, Phase 3 remediation construction activities are scheduled to continue at the Site. The contractor is scheduled to complete the assembly of the Jet Grout Plant system and commence the start-up and testing of the jet grouting system. The contractor will continue with the mobilization of personnel and equipment, and will continue to conduct Site preparations including completing the construction of the WMF, and fabric repairs to the temporary fabric enclosure (i.e., tent). In addition, the contractor will conduct general maintenance activities and housekeeping at the Site, as necessary. Dust suppression activities will be conducted, as necessary.