Previous estimates of volume of fuel recovered have been too liberal. AT&T has refined down the estimate and can now confidently account for 12,425 gallons of diesel recovered at the PSC Kent Facility. AT&T is determining fuel recovered from pressing sorbent booms, from product/water mixture sent to the Marvac Facility, product in soil removed, and product still in Baker Tank on site (estimated to be 1200 gallons).
AT&T has been taking core soil samples with a GeoProbe searching for pockets of fuel in the West Parking Lot and South Side of Generator Building.
West Parking Lot
The week of September 1 - 6, AT&T began excavating on west portion of parking lot to remove pockets of fuel and contaminated soil.
Diesel recovery increased significantly when the pea gravel surrounding the UST was exposed. However, as work progressed, it was decided not to excavate around the UST itself due to several safety and integrity issues related to exposing the tank, and therefore, any remediation will be left up to Shaw to do “in situ”.
Geo Engineers provided guidance on backfilling the area under the AST’s and around the water line south of the generator building.
As of this PolRep, clean up efforts are almost complete.
South Side of Generator Building
Fuel that spilled into the planter garden took many paths underground often following utility conduit lines. One path lead under the generator building, turned south exiting out to the South Side of the Generator Building, then turned east following the waterline.
AT&T has excavated and exposed the storm drain and water line which run parallel with each other in an east-west direction. Pockets of fuel were found and recovered.
Recovery of diesel along the water line south of the generator building at one point stalled due to safety issues brought up by PSC. Representatives from the City of Bothell were out on 9/16 to review plans to excavate underneath the water line. Water pressure in the water line was reduce to allow work to continue.
Generator Building
AT&T has been employing a bio-solution that is injected underground inside the Generator Building. The bio-solution breaks down the fuel and serves as a barrier to further migration.
Storm Drain and Pond
Early in this reporting period, additional skimming in catch basin #3 was conducted due to elevated readings of total petroleum hydrocarbons in water sample.
Subsequent water samples in catch basin and in pond have produced negligible results.
Booms are being changed out every Friday. Very slight sheen was observed in catch basins 2-4, but no detectable odor.
No sheen has been seen on the pond.
AT&T is enrolling in Department of Ecology's Voluntary Cleanup Program.
AT&T will continue to monitor ground water.
EPA is closing out the emergency response to this site. This is the Final PolRep.
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