NCG030085_Tier Status Notification_20211013

SHIELD
ENGINEERING
October 12, 2021
Zahid Khan
Regional Engineer, Land Quality Section
Energy, Mineral, and Land Resources
NC Department of Environmental Quality — Mooresville Regional Office
610 East Center Avenue, Suite 301
Mooresville, NC 28115
[e-mail]
RECEIVED
OCT 13 2021
DENR-GL..Iu.
Land Quality Sectlou
Mooresville Reryonal Offs .:
SUBJECT: Daimler Trucks North America — Mount Holly Truck Plant
NPDES Stormwater Permit Certificate of Coverage NCG030085
Tier Status Notification
Shield Project No. 1140109-08
Dear Mr. Khan,
On behalf of Daimler Trucks - Mount Holly (CDC NCG030085), Shield Engineering, Inc. (Shield)
is providing notification, as required by NCG030000 Part E, to update you on the Tier status of
Outfalls 001 and 002 based on the latest sampling event. Daimler Trucks - Mount Holly has
become aware of its Tier status changes and continuances for samples collected on September
80h (results received by Daimler Trucks — Mount Holly on September 291h). These changes and
continuances are as follows:
1. Tier 1 benchmark exceedance of Chemical Oxygen Demand at Outfall 001
The lab report dated September 27' indicated a Chemical Oxygen Demand concentration of 230
mg/I (benchmark is 120 mg/1).
2. Tier 3 continuance for benchmark exceedances of Zinc at Outfalls 001 and 002
The September 8th sampling event indicates a Tier 3 benchmark exceedance for Zinc at Outfall
001 and Outfall 002. The following table provides results of the last 4 exceedances of Zinc at
these outfalls.
Zinc benchmark = 0.126 mg/I
Outfall
Month
Jan-21
Feb-21
May-21
Sep-21
001
0.150
0.180
0.200
0.240
Zinc benchmark = 0.126 mg/1
Outfall
Month
Oct-20
Feb-21
May-21
Sep-21
002
0.170
0.260
0.270
0.140
4301 Taggart Creek Road www.shieldengineering.com Telephone [phone]
Charlotte, NC 28208 License No. F-0856

Daimler Trucks — Mount Holly October 12, 2021
Shield Project No. 1140109-08 Page 2
3. Tier 3 status exit for Total Suspended Solids at Outfalls 001 and 002
Daimler Trucks - Mount Holly has achieved 3 consecutive samples within benchmarks for TSS at
Outfalls 001 and 002, and therefore has exited Tier 3 for TSS at both outfalls per Part E, Table
5. The latest TSS data are shown below:
TSS benchmark = 100 mg/I
Outfall
Month
Mar-21
May-21
Sep-21
001
32
32
28
002
85
73
33
4. Tier 3 status exit for Copper at Outfall 001; Tier 3 status continuance for Copper at
Outfall 002
Based on the latest sample results, Daimler Trucks - Mount Holly has achieved 3 consecutive
samples within benchmarks for Copper at Outfall 001, and therefore has exited Tier 3 for Copper
at Outfall 001 per Part E, Table 5 (See data table below). Outfall 002 remains in Tier 3 for Copper
based on historical data.
Copper
Outfall
benchmark = 0.010 mg/I
Month
I Mar-21
I May-21
Sep-21
001
10.0056
10.0090
0.0081
Copper benchmark = 0.010 mg/I
Outfall
Month
Apr-19
Apr-20
I Feb-21
May-21
002
0.024
0.012
0.0130
1 0.0150
Daimler Trucks - Mount Holly has initiated Tier 1 and Tier 3 response for the benchmark
exceedances. If you have any questions or require further information, please contact Shield or
Sean Quarry with Daimler Trucks — Mount Holly at [e-mail].
Sincerely,
SHIELD ENGINEERING, INC.
4�
Melinda . Deene\"' Robert L. Griffin, PE
Senior Engineer President/CEO
Magdaline M. Tzannis
Senior Project Manager
cc: Sean Quarry, Daimler Trucks — Mount Holly
James Moore, NCDEQ - Mooresville
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ENGINEERING