2017-07-06 Duke Mayo Landfill 7305 Environmental Event Reporting

Mayo Landfill Facility - Solid Waste Reporting Page 1 of 4

Solid Waste Environmental Event Reporting

Event Title: Mayo Landfill Leachate Release
Report Date: July 6, 2017
Submitted to: NCDEQ Division of Waste Management (DWM)
Regulatory agency contact: Shawn McKee 919-707-8284
Duke Energy contact: Kimberlee Witt 336-215-4576

Duke Energy Facility: Mayo Steam Electric Plant Landfill
10660 Boston Road
Roxboro, NC 27574
Person County
Permit No.:7305-INDUS

1. Event Description
a. Date: discovered Thursday June 29, 2017 at approximately 8:36am
b. Material released
(Yes/No). Description if yes: landfill leachate
c. Summary:
• At approximately 8:30am, a blind flange on a riser structure at Station 26+00 along the landfill leachate forcemain from the lift station to the FGD Pond was observed
slowly leaking leachate due to a gasket failure;
• some of the leachate seeped through a joint in the concrete culvert and into Bowes
Branch;
• at approximately 3:30pm, the flange was replaced and flows from the leachate force
main flange ceased .
d. Field actions:
• All system pumps were shut off at approximately 8:47am;
• HDPE was placed at the bottom of the cleanout manhole to reduce infiltration into
stone layer;
• a vacuum truck was brought onsite to assist with removal of ponded leachate
recovering approximately 500 gallons;
• a gate valve allowing water to pass from the leachate lift station to the FGD pond
was closed at approximately 11:45 am for safety precautions to ensure no additional
water passed through the line as the flange was repaired;
• the blind flange was replaced with a site fabricated flange including a valve at
approximately 3:30pm.
2. Regulatory Contact
a. Date and time of regulatory contact:
Thursday June 29, 2017 approximately 3:00pm
Regulatory agency: NCDEQ Division of Waste Management (DWM)
Contact name/number: Primary - Shawn McKee 919-707-8284

Mayo Landfill Facility - Solid Waste Reporting Page 2 of 4

Summary:
Phone conversation describing discovery of the leachate release, field cleanup
activities, and that some leachate was believed to have been released into
Bowes Branch. A site inspection was set up for Monday July 3, 2017.
b. Date and time of additional regulatory agency contact:
Thursday June 29, 2017 approximately 4:30pm
Regulatory agency: NCDEQ Division of Water Resources NPDES Section
Contact name: Danny Smith contacted by Lori Tollie (Duke)
Summary:
Phone conversation to report that leachate from the force main was released to
Bowes Branch.

3. Regulatory Site Visit
Was a regulatory visit conducted (Yes/No)
a. Date and time of site visit:
July 3, 2017 arrival time: 11:00am, departure time: 12:00pm
b. Regulatory agency: NCDEQ DWM
c. Attendees: Shawn McKee, Elizabeth Werner
d. Duke Energy escort: Kimberlee Witt, Rob Miller
e. Areas inspected:
• Leachate double cleanout located at Station 26+00
• Concrete box culvert located in Bowes Branch
• Wheel wash improvements
f. Records reviewed: None
g. Issues indicated: None

4. Regulatory Recommendations:
• Sample existing piezometersPZ-32S and PZ-32D for boron and chlorides as potential
indicator for groundwater concerns

5. Duke Energy Follow-Up Actions:
• A permanent blind flange with valve will be fabricated and installed on the cleanout at
Station 26+00;
• the leachate forcemain system will be evaluated. If the forcemain evaluation
recommends system alterations, Duke will communicate with DWM and request
approval for modifications;
• sample piezometers PZ-32S and PZ-32D for boron and chlorides will be conducted the
week of July 10, 2017; results will be discussed with Elizabeth Werner, DWM
hydrogeologist.

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6. Photos:
(include description with each photo)
Photo 1 - cleanout blind flange at
Station 26+00 during leak
Photo 2 - cleanout at Station 26+00 with
temporary replacement flange and valve

Photo 3 - ponding area on June 29,
2017
Photo 4 - previous ponding area on July
3, 2017

Photo 5 - concrete culvert in Bowes
Branch
Photo 6 - seepage from joint in concrete
culvert on June 29, 2017

Mayo Landfill Facility - Solid Waste Reporting Page 4 of 4

cc: Ed Mussler - NDEQ DWM
Shannon Aufman - NCDEQ DWM
Elizabeth Werner - NCDEQ DWM
Ed Sullivan - Duke Energy
Bert Lea - Duke Energy
Jake Muessen - Duke Energy