Applying foam to excavated soil under the tent.

National Grid’s Remediation Contractor continued with site remediation activities, which included the delivery of construction materials, imported backfill material (clean fill), construction equipment and supplies. Installation of the on-site Waterloo Barrier Wall continued to progress from east to west across the northern part of the site. In addition, flushing and grouting activities of the Waterloo Barrier Wall joints commenced along the eastern part of the site. Record of construction surveys and construction stake-out surveys continued as site remediation activities progress. Shallow Excavation Area remedial activities continued inside the temporary fabric enclosure at Tent Position # 1 in the southeast corner of the site. Vapor Management System (VMS) operation continued at Tent Position # 1 and worker health and safety monitoring activities continued at the site. As of May 8, 2009, 15,722.5 tons of impacted materials have been transported off-site for disposal at the regulated disposal facilities. Noise and vibration monitoring activities were conducted during the on-site barrier wall sheet piling operations (Waterloo DNAPL Migration Barrier Wall).

Personnel and equipment decontamination pads were utilized throughout site operations.  Further delineation of work zones (i.e., exclusion, decontamination, and support) continued, as required. Maintenance of the on-site gravel access roads, parking areas and material staging areas, the imported backfill material (i.e., clean fill) stockpile covers, and maintenance of the perimeter privacy screen continued.  Imported clean fill materials continued to be staged in the central part of the site and utilized as backfill material for the Tent Position #1 Shallow Excavation Area and for the construction of a stabilized working platform for the Waterloo DNAPL Migration Barrier Wall sheet piling rig.  Maintenance of engineering controls and soil erosion and sediment control (SESC) measures continued. Odor and dust suppression activities were conducted, as necessary. National Grid’s consulting engineer continued to monitor the site activities with the fixed base community air monitoring program (CAMP) equipment.

Hammer inserting portion of the Waterloo barrier.

Personnel and equipment decontamination pads were utilized throughout site operations.  Further delineation of work zones (i.e., exclusion, decontamination, and support) continued, as required. Maintenance of the on-site gravel access roads, parking areas and material staging areas, the imported backfill material (i.e., clean fill) stockpile covers, and the perimeter privacy screen continued.  Imported clean fill materials continued to be staged in the central part of the site and utilized as backfill material for the Tent Position #1 Shallow Excavation Area and for the construction of stabilized working platforms for the Waterloo DNAPL Migration Barrier Wall sheet piling rig.  Maintenance of engineering controls and soil erosion and sediment control (SESC) measures continued. Odor and dust suppression activities were conducted, as necessary. National Grid’s consulting engineer continued to monitor the site activities with the fixed base community air monitoring program (CAMP) equipment.

CAMP data is reviewed and compared to specific NYSDEC/NYSDOH approved criteria, known as “Action Limits.” As a result of this evaluation process, site conditions are categorized into two categories, “Operational Condition” and “Action Condition.” The “Operational Condition” is applicable when the data is below the “Action Limits”, and means that normal operations can continue. The “Action Condition” occurs when one or more of the fifteen minute average measurements for Dust (PM10), Total Volatile Organic Compounds (TVOC), Naphthalene or Odor Intensity are greater than the background or upwind measurement by the specified “Action Limits.” Reaching an Action Level requires corrective action or stopping work until the condition is addressed or abates. During the period from May 4, 2009 through May 10, 2009, six fixed base CAMP units and one portable CAMP unit were in-use and measured TVOC and PM10. Fifteen-minute averages for TVOC and PM10 data remained in the Operational Condition. During the overnight hours of Friday, May 8, 2009 between 0537 Hours and 0630 Hours, elevated concentrations of PM-10 particulates were reported for a period of ten minutes at FAM-5 and 23 minutes at FAM-6. These elevated concentrations, which were below the Action Limit, were caused by high moisture (high humidity, rain and fog) and were not associated with site intrusive activities. These weather related conditions interfered with the true measurement of PM-10 at the sites and background concentrations reduced all but five minutes of the elevated concentrations below the action limit; therefore the site remained in the Operational Condition (less than the Action Limit). Weekly Reports of the CAMP data can be found as a separate tab in the Weekly Report Archive section.

For the week of May 11, 2009 through May 15, 2009, installation of the on-site Waterloo Barrier Wall will continue along the northern part of the site. Shallow Excavation Area remedial activities will continue within Tent Position # 1; where impacted material will be loaded out for off-site transport and disposal at approved and permitted facilities. Excavations are backfilled with imported fill materials. Work zone delineation and maintenance of the on-site gravel access roads, truck lining and tarping stations, personal and equipment decontamination pads, and the truck scale will continue. National Grid’s consulting engineer will continue to monitor the site activities with noise and vibration monitoring equipment. Maintenance of engineering controls and SESC measures will continue. Work zone air monitoring and VMS system inspection and performance monitoring will continue.  Odor and dust suppression activities will be conducted as necessary. National Grid’s consulting engineer will continue to monitor the site activities with CAMP equipment.