HomeMy WebLinkAbout7906_Duke_DanRiver_Area1DebrisRemoval_DIN26851_20161013Andrew Shull
Duke Energy
410 S. Wilmington Street
NCRH 15
Raleigh, NC 27601
o: 919.546.2104
c: 919.946.5835
October 13, 2016
Ms. Elizabeth Werner
North Carolina Dept. of Environmental Quality
Waste Management Division
1646 Mail Service Center
Raleigh, NC 27699-1646
Subject: Duke Energy Dan River Steam Station – Debris Removal
Dear Ms. Werner:
Per your recent conversation with Duke Energy personnel, debris was recently encountered
during coal residual removal activities within the former Ash Stack #1 at the Duke Energy Dan
River Steam Station. This letter outlines our proposed approach for removal and disposal of this
debris and soil.
On September 22nd, debris consisting of household garbage (glass, plastic, etc) and general
construction debris (metal pieces, wire, tile, shingles, etc) was discovered at the eastern edge of
the former Ash Stack #1. After the discovery of fibrous tile and shingles, the material was tested
and returned positive laboratory results for asbestos. Due to the presence of asbestos-
containing materials (ACM), a plan was developed to safely handle and remove the materials in
coordination with the North Carolina Division of Public Health – Health Hazards Control Unit.
The material was also tested by TCLP methods for Volatile Organic Compounds (VOCs), Semi-
volatile Organic Compounds (SVOCs), Polychlorinated Biphenyls (PCBs) and metals. The only
detections in the analyses were metals, with lead at a TCLP concentration of 5.7 mg/L.
We currently estimate that approximately 50 to 300 tons of debris and impacted soil exist in the
Ash Stack #1 area, which we are proposing to remove. Our goal is to remove the material in the
most effective way possible, given the ACM, while not changing the station’s small quantity
generator (SQG) status for this one-time event. In order to achieve this, we propose to stabilize
the material with Enviroblend and then transport and dispose the material to a non-hazardous
waste landfill after laboratory analysis confirms favorable TCLP lead results. Additional details
on our proposed Enviroblend approach are listed below:
The Enviroblend will be shipped to the site in 1 ton super sacks and will be added to the
soil at a 3-5 % ratio based on a volumetric estimate (roughly 1 supersack per 18 cubic
yards or 25 tons).
The Enviroblend will be incorporated into the soil via excavator bucket mixing, and would
be mixed ex-situ immediately adjacent to the excavation in a temporary stockpile.
Once the material has been properly mixed/stabilized it will be loaded into roll-off
containers. An additional composite TCLP sample will be collected from each roll-off
container to confirm that lead has been effectively stabilized, and the TCLP
concentration is below 5 mg/L.
Upon completion of the debris removal and any necessary over-excavation, confirmation
samples will be collected from the sidewalls and base of the excavation.
We are planning to implement this scope of work on Monday, October 17, 2016, to remain on
schedule for ash removal efforts. Duke Energy appreciates your time to review and provide
feedback on our proposed approach. If you have any questions or concerns regarding the
project or approach, please contact me at 919-546-2104.
Sincerely,
Andrew W. Shull, P.E.
Sr. Environmental Specialist