Projects

Building C Investigation and Soil Remediation

• Client:  National Semiconductor Corporation
• Location:  Santa Clara, California
• Project Manager:  Joshua D. Graber
• Principal-in-Charge:  Philip G Smith
• Regulation:  Regional Water Quality Control Board

Treadwell & Rollo has been providing environmental engineering services for NSC's Building C site, since 2004. We performed a soil remediation project inside a building over the 2009 Christmas-New Years holiday to mitigate contamination that had originated from past microchip research activities.  Preliminary tasks included completing a grid soil sampling investigation to delineate soil concentrations in-situ in order to prepare a soil excavation plan to remove VOC-impacted soil from beneath the building slab. Due to the nature of the work, a planned two-week facility shut down, and a fast-paced renovation schedule, the excavation was completed within two weeks.

Acting as the remediation contractor for our client we retained Pacific States Environmental to excavate an area approximately 70-feet-long by 30-feet-wide and 11-feet-deep and dispose of the soil, which was impacted with chlorobenzenes.  The area was saw cut and dug out, the VOC-impacted soil was removed in pre-defined sections, and disposed of as a Class II waste. The excavation was supervised by Environmental Services Manager Phil Smith, RG, CPGS, REA II, Senior Scientist and Project Manager Joshua Graber, REA I, and Senior Staff Geologist Louis Arighi, PG.  Soil vapor extraction and monitoring wells from prior remediation efforts were abandoned as they were encountered, and two foundation footings were carefully excavated around.

A horizontal well system was installed prior to backfilling to facilitate future groundwater treatment, if necessary. The perforated pipe was covered with drain rock and geotextile, followed by approximately four feet of controlled density fill and six feet of compacted soil.  Geotechnical Engineer Don Oman, performed oversight and compaction testing.