From an email from Rachel Loftin, a Project Manager with the EPA -
Dear NIBW Community Involvement Group -
I am sending this additional information as an update to last Friday's e-mail about a release of untreated water which occurred on Monday, November 23rd, from a drain pipe which is connected to the groundwater extraction and treatment system of the Central Groundwater Treatment Facility (CGTF).
Here's the additional information EPA has learned from the City of Scottsdale:
Again, and most importantly, we want to emphasize that this release did not impact the drinking water supplied by the Central Groundwater Treatment Facility (CGTF).
On Monday, November 23rd, a release of untreated water occurred when Well 75 was turned back on after being off for a couple of weeks while construction work was being conducted. The release was observed by operations staff within 10 minutes of turning Well 75 back on. There was not an alarm or electronic system notification, however CGTF personnel are always onsite during the start-up of the facility to handle any problems or emergency events. The well and CGTF were shut down within 10 minutes of the release.
The release originated at a drain pipe resulting in an overflow of between 500-900 gallons of water onto a grassy area in front of the south gate of the CGTF. The City cordoned off the spill area and collected a soil and groundwater sample. The soil results indicate non-detectable concentrations of TCE and PCE, and the groundwater results from the spill area are 9 micrograms per liter (ug/l) of TCE and 1 ug/l of PCE. These concentrations are quite low.
The data indicate that the public was not impacted by the release because of the short duration of the spill, low volume of water released, and the low detections of TCE and PCE in the spill area. The City returned the CGTF to service last Wednesday, November 25th, after repairs were made and the soil sample results were received.
The City found that 3 automatic valves which were supposed to be closed, were improperly wired and left in the open position. The staff then tried to close the drain pipe using the manual valves, but the manual valves would not shut properly. The personnel on-site shut down the well and the CGTF to stop the spill. As of last Monday (Nov. 23), the City fixed the automatic valve wiring and is in the process of replacing the manual valves.
The City responded promptly to:
- Shut off the well and CGTF to stop the spill;
- Cordon off the spill area in the park;
- Collect a water and soil sample at the spill location;
- Obtain expedited sampling results,
- Wire the automatic valves properly, and
- Replace the 2 manual valves that would not shut/seal properly. This work is in progress.
What Happens Next?
The City is compiling an incident report with photo documentation and recommendations for next steps which will be submitted to EPA by the end of this week. I will share this report with all of you when I receive it.
Vicki, ADEQ, and I will be contacting you in early January to being planning for the annual community meeting to be held early next year.
Please contact me at 415/972-3253 or by e-mail if you have any questions regarding this information. Enjoy the holiday season! I look forward to meeting you all in person early next year.
Remedial Project Manager
U.S. EPA, Region 9
Superfund Division, SFD-6-2
75 Hawthorne Street
San Francisco, CA 94105
As more info becomes available, including the time and location of the next meeting of the North Indian Bend Wash Superfund Site Community Involvement Group, I'll post it here.