National Grid’s Remediation 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 Remediation Contractor continued Phase 3 remediation construction activities at the Site. The contractor continued general maintenance of the Site, commenced the installation of shallow steel sheet piles, and completed the construction of the foundations for the proposed Grout Plant silos. The Remediation Contractor continued with the mobilization of personnel and equipment, and conducted Site preparations and detailed layout efforts for the Phase 3 Composite 120-foot deep DNAPL Migration Barrier Wall Installation project. The jet grouting contractor (JGC) and waste management and emergency response (WM/ER) contractor were involved with the preparation of pre-mobilization submittals and scheduling activities for the project.

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 September 19, 2011 through September 25, 2011, six fixed base units and one portable CAMP unit 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 September 26, 2011 through September 30, 2011, Phase 3 remediation construction activities are scheduled to continue at the Site. The remediation contractor is scheduled to complete the installation of the shallow steel sheet piling as well as construction of the Grout Plant platform and the Phase 3 Jet Grout Working Platform. The Remediation Contractor will continue with the mobilization of personnel and equipment, and will continue to conduct Site preparations including the construction of the waste management facility (WMF), and commence the temporary fabric enclosure (i.e., tent) fabric repairs. In addition, the contractor will conduct general maintenance activities and housekeeping at the Site, as necessary. Dust suppression activities will be conducted, as necessary.