NC0046426_Fact Sheet_20230725

NCDEQ / DWR / NPDES
EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL
NPDES Permit NCO046426
Catherine Shadwell, Compliance & Expedited Permitting Unit / [phone] July 2023
FACILITY INFORMATION
Applicant/Facility Name
Wilkes County Schools (Thomas J Spicer, ORC)
Traphill Elementary School WWTP
Applicant Address
613 Cherry St North Wilkesboro, NC 28659
Facility Physical
Address/Mailing Address
9794 Traphill Rd Traphill, NC 28685
Permitted Flow (MGD)
0.004 MGD
Type of Waste
100% Domestic, < 1 MGD
Facility Class
WW-1
County
Wilkes
Permit Status
Renewal
Regional Office
WSRO
STREAM CHARACTERISTICS
Receiving Stream
Little Sandy Creek
Stream
Classification
C
Stream Segment
12-46-4-10
Outfall Lat.
360 20' 24" N
7Q10 - Summer (cfs)
0.49
Outfall Long.
810 02' 13" W
7Q10 - Winter (cfs)
0.78
Drainage basin
Yadkin -Pee Dee
30Q2 (cfs)
—
Subbasin
03-07-01
Average Flow (cfs)
3.12
HUC
030401010405
IWC (%)
1.25% (summer) /
0.79% (winter)
303(d) List
Not listed.
BASIC INFO FOR EXPEDITED PERMIT RENEWAL
Does permit need Daily Max NH3 limits?
No, already present in permit
Does permit need TRC limits/footnote?
No, site uses UV Disinfection
Does permit have toxicity testing?
No
Does permit have any Special Conditions?
es, nutrient reopener for high rock lake and temporary
means of disinfection
Does permit have instream monitoring?
No
New expiration date:
Sep 30, 2028
Facility Summary
School which has a private, minor WWTP with a permitted discharge of 0.004MGD. The permit was
originally issued in 1981. This facility utilizes the following components.
• Dual (2) Septic tanks
• Dosing tank with two siphons (1 backup)
• Two (2) surface sand filters
• Ultraviolet disinfection system
• Pump station and force main
• Blower
Renewal Summary
This renewal contains the following changes:
• Added the facility grade to Section A. (L).
• Updated the effluent table in Section A. (L) with eDMR parameter codes.
Fact Sheet for Permit Renewal
July 2023 - NPDES Permit NCO046426 - Page 1

• Updated Section A. (4.) to reflect current federal requirements for Electronic Reporting of
Discharge Monitoring Reports.
• Added regulatory citations.
• Added section A. (3.) regarding temporary means of disinfection since site uses UV.
Compliance History
• Looking from 2018-present — site has received 1 NOV in 2020, one of the syphons needed to be
repaired.
Comments on Draft Permit
Fact Sheet for Permit Renewal
July 2023 - NPDES Permit NC0046426 - Page 2

IWC Calculations
Facility: Traphill Elementary School WWTP
Permit No.: NC0046426
Prepared By: Catherine Shadwell
Enter Design Flow (MGD): 0.004
Enter s7Q10 (cfs): 0.49
Enter w7Q10 (cfs): 0.78
Total Residual Chlorine (TRC)
Ammonia (Summer)
Daily Maximum Limit (ug/1)
Monthly Average Limit (mg NH3-N/1)
Design Permitted
Design
Permitted
s7Q10 (CFS) 0.49 0.49
s7Q10 (CFS)
0.49
0.49
DESIGN FLOW (MGD) 0.004 € 0.2
DESIGN FLOW (MGD)
0.004 €
0.2
DESIGN FLOW (CFS) 0.0062 0.31
DESIGN FLOW (CFS)
0.0062
0.31
STREAM STD (UG/L) 17.0 17
STREAM STD (MG/L)
1.0
1
Upstream Bkgd (ug/1) 0 0
Upstream Bkgd (mg/1)
0.22
0.22
IWC (%) 1.25 38.75
IWC (%)
1.25
38.75
Allowable Conc. (ug/1) 1361 44
Allowable Conc. (mg/1)
62.6
2.2
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Design Permitted
Design
Permitted
Fecal Coliform
w7Q10 (CFS)
0.78
0.78
Monthly Average Limit: 200/100m1 € 200/100m1
DESIGN FLOW (MGD)
0.004
0.2
(If DF >331; Monitor)
DESIGN FLOW (CFS)
0.0062
0.31
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
1.8
Dilution Factor (DF) 80.03 2.58
Upstream Bkgd (mg/1)
0.22
0.22
IWC (%)
0.79
28.44
Allowable Conc. (mg/1)
200.6
5.8
*2B .0404 (c) Applies
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/l, Monitor Only
2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals)
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis)
If the allowable ammonia concentration is > 35 mg/L, no limit shall be imposed
By Policy dischargers < 1 MGD get limits no lower than 2 & 4 due to BAT
* From 2B .0404(c) - Winter Limits can be no less stringent than
2 times the summer limits
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)