NC0036773_Fact Sheet_20241030

NCDEQ / DWR / NPDES
EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL
NPDES Permit NCO036773
Sara Bassett / Compliance & Expedited Permitting Unit / sara.bassett(kdeq.nc.gov / October 2024
FACILITY INFORMATION
Facility Contact/Facility Name
Dixon Medlin, Laurinburg WTP
Mailing Address
P.O. Box 249 Laurinburg NC 28352
Facility Physical Address
603 Lauchwood Dr Laurinburg NC 28352
Max, Monthly Avg Flow Limit
(MGD)
0.076
Type of Waste
Filter backwash, 100% Industrial
Facility Class
PC-1
County
Scotland
Permit Status
Renewal
Regional Office
FRO
STREAM CHARACTERISTICS
Receiving Stream
Big Branch
Stream
Classification
C;Sw
Stream Segment
14-33-2-1
Outfall 001
Latitude
34 45 05.0 N
7Q10 - Summer (cfs)
0.05
Outfall 001
Longitude
79027'56.9"W
7Q 10 - Winter (cfs)
-
Drainage basin
Lumber
30Q2 (cfs)
-
Subbasin
03-07-55
Average Flow (cfs)
-
HUC
030402040202
303(d) List
No
BACKGROUND:
From last Factsheet: This permit is noted on the application as being a conventional WTP. Its
source water is groundwater and the process has no coagulation and settling processes. There is
some chemical addition, aeration and mixing, followed by filtration primarily to remove iron. It is
not a greensand process, but for permitting purposes has been considered closer to this than a
traditional, conventional plant. Filter backwash is dechlorinated as it is discharged to the receiving
stream.
FACILITY SUMMARY
Conventional Water Treatment Plant with a discharge of wastewater from media filter -backwash.
This water treatment plant currently has a design potable flowrate of 8 MGD and a maximum,
monthly average discharge of 0.066 MGD. This facility is located at the Laurinburg WTP (603
Lauchwood Drive) south of Laurinburg, in Scotland County. Wastewater treatment includes the
following wastewater treatment components:
• Dechlorination
• Flow Measurement
Fact Sheet for Permit Renewal
October 2024 - NPDES Permit NCO036773 - Page 1

RENEWAL SUMMARY
• Section A. (3.) has been updated regarding electronic submission of effluent data. Federal
regulations require electronic submittal of all discharge monitoring reports (DMRs).
• A maximum monthly average flow limit has been added to section A. (L) and monitoring
requirements have been updated.
• The maximum average monthly flow has been updated in the Supplement to Permit Cover Sheet.
• A daily maximum limit for Fluoride has been added to Section A. (L).
• The compliance schedule has been removed for copper.
• Please note that the practical quantitation limit (PQL) for Total Copper is 2 µg/L (per the
Inorganic Chemistry Branch of the Division of Water Resources Water Sciences Section) and
monitoring data should be reportable down to these levels.
• In accordance with the 2020 Division of Water Resources Water Treatment Plant permitting
strategy for conventional facilities, Whole Effluent Testing requirements have been changed from
monitoring only to a pass/fail limit. See Section A. (L) and Section A. (2.).
• The parameter of Hardness has been updated in Section A. (1.).
• The parameters of TKN and Nitrate/Nitrite have been added to Section A. (L) with a footnote. The
sample type for the parameter of Total Nitrogen has been changed to calculated.
COMPLIANCE HISTORY
1 enforcement case in 2021 for limit violation for Total Fluoride monthly average exceedance. Several
NOVs in past permit cycle.
NCG59 GENERAL PERMIT ELIGIBILITY (FOR CONVENTIONAL & GREENSAND ONLY)
No eligible due to fluoride and copper limits in individual permit.
WHOLE EFFLUENT TOXICITY (WET) TESTING
Failed 4 of 12 in the last 3 years.
This renewal will transition WET testing from monitoring to a limit following the departments
2020 Water Treatment Plant permitting strategy for conventional facilities.
The effluent concentration defined as treatment two in the procedure document is 90 %. The
testing shall be performed as a Ceriodaphnia dubia 7-day pass/fail test. The tests will be
performed during the months of February, May, August and November. These months signify
the first month of each three month toxicity testing quarter assigned to the facility. Effluent
sampling for this testing must be obtained during representative effluent discharge and shall be
performed at the NPDES permitted final effluent discharge below all treatment processes.
REASONABLE POTENTIAL ANALYSIS
Copper and Fluoride data both suggest reasonable potential to exceed water quality standard.
Monthly monitoring with limits will be maintained. A daily maximum limit has been added for Fluoride.
There were a few mistakes with the units of measure entered into eDMR. Lab reports were requested, and
RPA was run using corrected data.
COMMENTS ON DRAFT PERMIT
Fact Sheet for Permit Renewal
October 2024 - NPDES Permit NCO036773 - Page 2

Fact Sheet for Permit Renewal
October 2024 - NPDES Permit NC0036773 - Page 3