Approval of Modifications to the Final Remedy at the Hewlett-Packard Building 15 Site
Summary
SCH Number
2004108317
Public Agency
Department of Toxic Substances Control
Document Title
Approval of Modifications to the Final Remedy at the Hewlett-Packard Building 15 Site
Document Type
NOE - Notice of Exemption
Received
Posted
10/22/2004
Document Description
The Department of Toxic Substances Control is modifying the final remedy for the Hewlett-Packard Building 15 Site to include injection of potassium permanganate into shallow groundwater.
Contact Information
Name
Janet Naito
Agency Name
Department of Toxic Substances Control Northern California
Contact Types
Lead/Public Agency
Phone
Location
Cities
Palo Alto
Counties
Santa Clara
Notice of Exemption
Exempt Status
Other
Type, Section or Code
General Rule, Section 15061(b)(3
Reasons for Exemption
1. The groundwater extraction and treatment system downgradient of the treatment area will continue to operate and control the groundwater plume from this Site. Based upon the pilot study results, the potassium permanganate will be used up before reaching the downgradient extraction wells, located approximately 250 to 350 feet away. Therefore, it will not interfere with the continued operation of the remainder of the extraction system.
2. The project is completely in-situ and will not pose any threat to the local air quality. The treatment zone is developed within the groundwater from approximately 20 to 60 feet bgs. The treatment area is located under an asphalt parking area. No hazardous air releases were detected during the Pilot Test.
3. The site is fully developed for research and development uses. The closest residence is over 0.25 miles away from the Site. There are no endangered species, either plant or animal, on the Site or in the site vicinity.
4. Shallow groundwater is not used for drinking water at the Site or in the Site vicinity. Drinking water to this area and the nearby residential community is provided by Hetch Hetchy. Groundwater wells installed in the neighborhood approximately 0.25 miles away are generally used for irrigation.
5. Temporary injection wells will be installed and abandoned under permit from the Santa Clara Valley Water District.
6. The purple potassium permanganate solution is a strong oxidizing agent. It is not volatile or flammable. Pre-mixed 5% potassium permanganate solution will be delivered to the treatment area and stored in secondarily contained 500 gallon containers to prevent spillage. Visquene will be placed around each injection point and all fittings along the absorbent socks to prevent chemical spills during injection.
7. Based upon the pilot study results, a semi-annual post-injection monitoring program will be implemented to monitor groundwater conditions within and downgradient of the treatment area. This is sufficient to monitor the effectiveness of the potassium permanganate solution in destroying the VOCs and to monitor the chromium levels in groundwater.
8. Site workers will comply with the health and safety requirements of Title 8, California Code of Regulations and 29 Code of Federal Regulations, section 1910.120 during handling of potassium permanganate.
9. The project does not require a Storm Water Pollution Prevention Plan.
10. The drilling and injection work will be conducted Monday through Friday between 8am and 8pm or Saturday between 9am and 6pm, which is within the hours allowed under the Palo Alto Municipal Code, Title 9, Chapter 9.10, Noise.
Disclaimer: The document was originally posted before CEQAnet had the capability to host attachments for the public. To obtain the original attachments for this document, please contact the lead agency at the contact information listed above. You may also contact the OPR via email at state.clearinghouse@opr.ca.gov or via phone at (916) 445-0613.