NC0067008_Draft Factsheet_20230530

NCDEQ / DWR / NPDES
EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL
NPDES Permit NCO067008
Catherine Shadwell, Compliance & Expedited Permitting Unit / [phone] May 2023
FACILITY INFORMATION
Facility Name
Old Cove Creek WWTP
Applicant Name
Water Quality Lab and Operations, Inc (Paul Isenhour, president)
Applicant Address
P.O. Box 1167 Banner Elk, NC 28604
Facility Physical
Address/Mailing Address
Physical — 207 Dale Adams Road Sugar Grove, NC 28679
Mailing — 247 Winklers Creek Rd, Suite B Boone, NC 28607
Permitted Flow (MGD)
0.01 MGD
Type of Waste
100% Domestic, < 1 MGD
Facility Class
WW-1
County
Watauga
Permit Status
Renewal
Regional Office
WSRO
STREAM CHARACTERISTICS
Receiving Stream
Cove Creek
Stream
Classification
C
Stream Index
8-15
Outfall Lat.
360 15' 45" N
7Q 10 - Summer (cfs)
4.1
Outfall Long.
810 4705" W
7Q10 - Winter (cfs)
6
Drainage basin
Watauga
30Q2 (cfs)
10.3
Subbasin
04-02-01
Average Flow (cfs)
48
HUC
060101030302
IWC (%)
Summer: 0.38%
Winter 0.26%
303(d) List
Not listed.
Facility Summary
Watauga County Board of Commissioners operates a 100% domestic minor facility with an extended
aeration wastewater treatment system. The permit was originally issued in 1987, this is a relatively small
treatment plant that serves the neighboring recreation center and daycare (about 65 people). No recent
reoccurring issues. The facility includes the following components...
• Aeration Basin
• Clarifier
• Chlorination
• De -chlorination
• Return Sludge holding tank.
Renewal Summary
This renewal contains the following changes:
• Removed pH footnote and moved pH standards to table in section A.(L) in order to keep formatting
consistent.
• Changed flow sample type from instantaneous to continuous since flow is 0.01MGD — in order to
determine compliance with 15A NCAC 2B.0505
• Updated section A (2) to be in compliance with most updated language.
• Updated outfall map
Compliance History
Most recent NOV was 2014.
Fact Sheet for Permit Renewal
May 2023 - NPDES Permit NCO067008 - Page 1

Comments on Draft Permit
- Minor grammar and formatting edits
- No significant comments on draft.
Fact Sheet for Permit Renewal
May 2023 - NPDES Permit NCO067008 - Page 2

IWC Calculations
Facility: Old Cove Creek WWTP
Permit No.: NCO067008
Prepared By: Catherine Shadwell
Enter Design Flow (MGD): 0.01
Enter s7Q10 (cfs): 4.1
Enter w7Q10 (cfs): 6
0.2 <= Permitted Flow if Different from Design
Total Residual Chlorine (TRC)
Ammonia (Summer)
Daily Maximum Limit (ug/1)
Monthly Average Limit (mg NH3-N/1)
Design
Permitted
Design
Permitted
s7Q10 (CFS)
4.1
4.1
s7Q10 (CFS)
4.1
4.1
DESIGN FLOW (MGD)
0.01
0.2
DESIGN FLOW (MGD)
0.01
0.2
DESIGN FLOW (CFS)
0.0155
0.31
DESIGN FLOW (CFS)
0.0155
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 (%)
0.38
7.03
IWC (%)
0.38
7.0294785
Allowable Conc. (ug/1)
4514
242
Allowable Conc. (mg/1)
207.3
11.3
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Design
Permitted
Design
Permitted
Fecal Coliform
w7Q10 (CFS)
6
6
Monthly Average Limit:
200/100ml
200/100ml
DESIGN FLOW (MGD)
0.01
0.2
(If DF >331; Monitor)
DESIGN FLOW (CFS)
0.0155
0.31
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
1.8
Dilution Factor (DF)
265.52
14.23
Upstream Bkgd (mg/1)
0.22
0.22
IWC (%)
0.26
4.91
Allowable Conc. (mg/1)
613.4
32.4
*213 .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/I, 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)