Case Study: Landfill Excavation at Oliktok

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Case StudyLandfill Excavation at Oliktok

• For the 2008 Alaska Forum on the Environment
• by Tamar Stephens
• Alaska Department of Environmental Conservation
• Contaminated Sites Program

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Background

• With climate change, the sea ice is diminishing.
• As the ice recedes, it provides less buffering
  from storm action, resulting in faster coastal
  erosion.
• Old landfills/dumps located along the coast are
  at greater risk of erosion.

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Introduction

• This presentation is a case study of a landfill
  at a North Slope Air Force facility, the Oliktok
  Long Range Radar Station.
• Old landfills on the north slope were probably
  expected to stay frozen forever.
• Storm action and erosion led to an interim action
  at Oliktok a few years ago.
• Increased coastal erosion and storm action
  ultimately led to a decision to remove the
  Oliktok landfill.
• This case study illustrates the importance of
  removing coastal landfills that are subject to
  erosion, to protect the aquatic resources from
  solid waste, hazardous materials, and
  contaminated soil found within the landfill.

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Oliktok Long Range Radar Station
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Location of Landfill (LF001)
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Erosion from 2000 Storm
In 2001, an old dump site (LF001) was found to be
significantly eroded by a storm event that
occurred in 2000. Drums and other wastes were
washed into the Beaufort Sea and oil was
released.
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This area is used for subsistence activities.
The dump is directly adjacent to a fish camp, and
was used as a boat launch for whaling expeditions
until the 2001 erosion problems.
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2001 Initial Response
Booms were used to capture sheen from drums
exposed by erosion.
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2001 Emergency Response
A time critical removal effort stopped release of
PCB-containing oil from corroding drums.
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Erosion control was installed
Geo-fabric webbing was installed to help control
erosion.
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Erosion control
Erosion control was completed by covering the
webbing with clean backfill.
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2007 Clean Sweep

• The Air Force Clean Sweep program was
  implemented at Oliktok in 2007.
• By this point in time, both DEC and the Air Force
  had concluded that coastal erosion was a
  significant force.
• Clean Sweep included removal of the coastal
  landfill (LF001).

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What we knew before excavating the LF001 landfill

• Previous erosion occurred petroleum sheen and
  low levels of PCBs were detected.
• Subsequent sampling identified an area with low
  level PCB soil contamination in the middle of the
  landfill.
• Sampling also identified an area with petroleum
  contamination surrounding the PCB area.
• Sampling did not detect any significant
  contamination in other areas of the landfill.

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Landfill was excavated in early spring 2007
Soil was still frozen. Frozen soil allowed better
vehicular access. Frozen conditions minimized
water problems.
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First was removal of an area known to have
PCB-contaminated soil
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Next was removal of a surrounding area with
petroleum-contaminated soil.
PCB soil in super sacks inside the hangar
Petroleum soil is stockpiled inside the hangar
This photo shows PCB soil in super sacks and
petroleum soil in a stockpile. Soil is
currently stored inside the hangar.
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Small ferrous (iron) items were removed with an
industrial magnet.
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Small non-ferrous items were removed by hand.
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Heating oily substance for easier removal
A drum with product is heated to make the
contents less viscous so it can be pumped into a
new drum for removal.
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Current Status
Floor of LF001 early fall 2007. The landfill was
excavated to permafrost. Sampling shows PCBs in
various places on the floor. Excavation to
remove remaining PCBs is planned for 2008.
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Sidewall and Floor Confirmation Sampling of LF001
landfill
PCBs gt 1 mg/kg
PCBs gt 10 mg/kg
POL gt method 1
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Potential hazardous waste was found throughout
the landfill.

• Drums with product
• Drums with oily residue
• Capacitors and small transformers (PCB sources)
• Transformer casings (PCB sources)
• Large fluorescent light ballasts (PCB sources)
• Nickel-iron batteries
• Lead-acid batteries
• Asbestos-containing material

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During excavation, presumed clean soil was in
stockpiled at one end.

• Confirmation sampling showed low levels of PCBs
  throughout the stockpile of presumed-clean soil
  in the landfill. Thus, entire volume, about
  5,000 cubic yards, has to be managed as PCB soil.
• Confirmation sampling showed PCBs in the
  petroleum soil stockpile in the hangar thus
  this soil also needs to be managed as PCB soil.

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New Stockpile Location
Stockpiled soil was removed from LF001 and LF002
and placed in a long-term stockpile in a location
not vulnerable to storm action, late summer 2007.
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Stockpiled soil from LF002 being moved to new
long term stockpile location
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Whats Next

• Additional excavation of the floor of the
  landfill to remove remaining PCB-contaminated
  soil later this winter (2008).
• Evaluate options for managing stockpiled soil
  with low levels of PCBs.

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Lessons Learned

• Landfill characterization cannot be done without
  removing everything.
• Assume that you dont know what is in the
  landfill, and will need to characterize and
  segregate as you go.
• Sources of contamination are likely to be present
  throughout.

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Thank you

• To the Air Force and to BEM Systems for
  photographs and figures used in the presentation.

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The End
Tamar Stephens [phone] tamar.stephens_at_alask
a.gov