4903_IredellCoMSWLF_LFGExccedanceProgressUpdateNovember2024_FID1913903_20241118

CEC
Carlson Environmental Consultants, pc
Landfill Gas and Solid Waste Specialists

1127 Curtis Street Ste 100 Monroe NC 28112 Phone [phone] ·Fax [phone]
Orlando, FL · Tampa, FL · Atlanta, GA · Columbia, SC · Richmond, VA · Statesville, NC
Olympia, WA · Cookeville, TN · Tullytown, PA
www.cecenv.com

November 15, 2024

Ervin Lane
Solid Waste Section
NCDEQ - Division of Waste Management
Raleigh Regional Office 1646 Mail Service Center
Raleigh, NC 27699-1646

Subject: Q1 2024 Methane Migration Monitoring Exceedances – Remediation Plan
Monthly Progress Update – September 2024
Iredell County Subtitle D Lined Landfills/Closed Unlined C&D Landfill
Statesville, North Carolina Solid Waste Permit No. 49-03
Dear Ervin:
On behalf of Iredell County (County), Carlson Environmental Consultants, PC (CEC) is submitting
to the North Carolina Department of Environmental Quality (NCDEQ) Division of Waste
Management Solid Waste Section (SWS) the subject remediation plan progress updates for a
recent methane migration monitoring exceedance detected at the Subtitle D Lined
Landfills/Closed Unlined C&D Landfill facility that is owned and operated by the County.
As previously reported to NCDEQ in a notification letter dated March 18, 2024 and the subsequent
remediation plan dated May 14, 2024, there was one (1) perimeter gas probe location with
methane detections above the 5% lower explosive limit (LEL) during the first quarter 2024
monitoring event: MP-6A (53.1%).
Pursuant to NCAC 13B .1626(4)(c)(iii), the County has commenced implementation of the
remediation plan for explosive gas release at this location. In accordance with NCAC 13B
.1626(4)(c)(iii), the plan describes the nature and extent of the exceedance and proposed
remedies. The below remediation plan progress updates are being provided to NCDEQ for the
month of September 2024:
• MP-6A was monitored weekly in October. Throughout the monitoring period, MP-6A has
fluctuated above and below 5%. Methane concentrations were first read below 5% at MP-6A as of May 16, 2024. However, MP-6A was read above 5% again as of May 28, 2024
and remained above the 5% threshold until June 20, 2024, at which time it was read
below 5%, and remained below the 5% threshold until July 29, 2024, when it was then
read above 5% as of August 7, 2024 and has remained above the 5% throughout October.
As stated in the remediation plan submitted to NCDEQ MP-6A must remain below the 5%
LEL for a consecutive two (2) months.
• Barhole punch and sampling occurred at four (4) locations between MP-6A and the
northwestern landfill perimeter on May 23, June 18, July 17, August 21, September 20,
and October 24, 2024. Methane was not detected above 5% at any barhole punch
location. Monthly barhole punch and sampling at these locations will continue in October.
Ervin Lane November 15, 2024
Page 2
• Weekly monitoring at the ICATS office structure was completed in August, and methane
was not detected above 1.25% during any monitoring period. Because methane continued
to be above 5% at MP-6A, weekly monitoring of the ICATS office structure will continue
in November 2024.
• During the month of July, the County began the project of extending the toe drain located
along the Northwestern side of Phase 4. The project continued through the month of
August, upon completion, it will be connected on both ends to the active LFG collection
system. As of the end of October, the toe drain lid has been completed and both ends
have been connected to the LFG collection system.
• Flare upgrades in order to assist with stabilizing system vacuum throughout the wellfield
are temporarily delayed due to a parts delay.
If you have any questions regarding this remediation plan, or require additional information,
please contact the undersigned at [phone].
Sincerely,

Kathryn Fauerby
Carlson Environmental Consultants, PC
CC: Teddy Boller, Iredell County
Jeff Webster, Iredell County
Brock McNabb, PE, CEC
Amanda Higgs, CEC

EXHIBIT A

Methane Monitoring Data Summary

(March 2024 – October 2024)
Permit ID Device ID Date and
Time of Day
Initial
% LEL
Stabilized
% LEL
% CH4
(volume)
% O2
(volume)
% CO2
(volume)
MP-6A IRDLMP6A 3/15/2024 13:32 >100 >100 53.10 0.00 38.10
MP-6A IRDLMP6A 3/22/2024 10:13 >100 >100 52.10 1.80 34.80
MP-6A IRDLMP6A 3/28/2024 10:54 >100 >100 57.60 0.00 38.30
MP-6A IRDLMP6A 4/5/2024 07:56 >100 >100 46.40 1.60 34.50
MP-6A IRDLMP6A 4/11/2024 14:12 >100 >100 61.80 0.10 37.80
MP-6A IRDLMP6A 4/18/2024 10:31 >100 >100 57.80 0.60 38.80
MP-6A IRDLMP6A 4/25/2024 09:59 >100 >100 43.70 1.90 36.10
MP-6A IRDLMP6A 5/2/2024 09:13 >100 >100 30.00 2.70 33.20
MP-6A IRDLMP6A 5/8/2024 13:18 >100 >100 8.00 10.40 16.40
MP-6A IRDLMP6A 5/16/2024 08:12 48.00 48.00 2.40 15.40 8.20
MP-6A IRDLMP6A 5/24/2024 07:53 14.00 14.00 0.70 15.60 6.40
MP-6A IRDLMP6A 5/28/2024 13:15 >100 >100 8.70 6.50 20.80
MP-6A IRDLMP6A 6/7/2024 12:43 >100 >100 25.00 2.80 31.10
MP-6A IRDLMP6A 6/11/2024 12:12 >100 >100 25.50 1.10 34.50
MP-6A IRDLMP6A 6/20/2024 09:56 30.00 30.00 1.50 5.30 22.60
MP-6A IRDLMP6A 6/25/2024 08:03 0.00 0.00 0.00 8.30 17.10
MP-6A IRDLMP6A 7/3/2024 13:02 2.00 2.00 0.10 15.80 10.30
MP-6A IRDLMP6A 7/11/2024 13:27 0.00 0.00 0.00 15.80 9.90
MP-6A IRDLMP6A 7/19/2024 15:14 0.00 0.00 0.00 19.70 3.80
MP-6A IRDLMP6A 7/25/2024 15:07 0.00 0.00 0.00 21.20 2.30
MP-6A IRDLMP6A 7/29/2024 14:15 0.00 0.00 0.00 20.60 1.70
MP-6A IRDLMP6A 8/7/2024 08:27 >100 >100 25.90 3.40 19.40
MP-6A IRDLMP6A 8/12/2024 09:36 >100 >100 37.00 2.90 24.10
MP-6A IRDLMP6A 8/20/2024 14:08 >100 >100 44.30 3.00 29.00
MP-6A IRDLMP6A 8/22/2024 13:52 >100 >100 45.70 2.90 30.70
MP-6A IRDLMP6A 8/30/2024 08:59 >100 >100 37.60 3.80 29.30
MP-6A IRDLMP6A 9/3/2024 08:18 >100 >100 44.70 1.80 34.30
MP-6A IRDLMP6A 9/9/2024 09:14 >100 >100 46.80 0.70 35.20
MP-6A IRDLMP6A 9/16/2024 10:17 >100 >100 35.90 1.20 33.20
MP-6A IRDLMP6A 9/23/2024 11:00 >100 >100 43.80 0.30 34.60
MP-6A IRDLMP6A 10/1/2024 12:45 >100 >100 56.00 0.30 36.70
MP-6A IRDLMP6A 10/8/2024 11:14 >100 >100 59.60 0.60 36.20
MP-6A IRDLMP6A 10/18/2024 08:14 >100 >100 45.40 2.40 30.20
MP-6A IRDLMP6A 10/21/2024 08:44 >100 >100 33.20 2.40 28.20
MP-6A IRDLMP6A 10/28/2024 09:31 >100 >100 9.00 2.00 24.00
GEM 5000 gas analyzers were used for all monitoring events and were calibrated appropriately prior to monitoring.
Methane Monitoring Data Summary
March 2024 - October 2024
Iredell County Subtitle D Lined Landfills/Closed Unlined C&D Landfill (Permit No. 49-03)