NC0025879_technical correction_20240619

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
Mayor Shaun Adams
Town of Robbinsville
P.O. Box 126
Robbinsville, NC 28711-0126
Dear Permittee:
NORTH CAROLINA
Environmental Quality
June 19, 2024
Subject:
NPDES Permit NCO025879
Technical Correction
Robbinsville WWTP
Graham County
The Division has reviewed the subject permit and made the following minor corrections:
➢ The Supplement to Permit Cover Page has been updated to correct the treatment
system components
➢ Parts I A. (1.) and A. (2.) have been reformatted for consistency with other permits of
this type
➢ Part I A. (3.) has been updated with current deadlines for EPA compliance
➢ Part I A. (4.) has been reworded to clarify the sampling requirements for Total Mercury
Remove the pages from your existing permit and replace them with the attached pages. This
permit correction does not change any permit limits or monitoring requirements.
This permit modification is issued pursuant to the requirements of North Carolina General
Statute 143-215.1 and the Memorandum of Agreement between North Carolina and the U.S.
Environmental Protection Agency dated October 15, 2007 (or as subsequently amended). Insert
the attached pages into your permit and discard the old pages.
If any parts, measurement frequencies or sampling requirements contained in this
modification are unacceptable to you, you have the right to an adjudicatory hearing upon written
request within thirty (30) days following receipt of this letter. This request must be in the form of
a written petition, conforming to Chapter 150B of the North Carolina General Statutes, and filed
with the Office of Administrative Hearings (6714 Mail Service Center, Raleigh, North Carolina
27699-6714). Unless such demand is made, this decision shall be final and binding.
This permit is not transferable except after notice to the Division. The Division may
require modification or revocation and reissuance of the permit. This permit does not affect the
legal requirements to obtain other permits which may be required by any other Federal, State, or
Local governmental regulation.
North Carolina Department of Environmental Quality I Division of Water Resources
�.
40R�THCARQLINA 512 North Salisbury Street 11611 Mail Service Center I Rai eigh, North Carol ina27699-1611
"' a °"�✓ 919.707.9000

If you have any questions concerning these changes, please contact Charles H. Weaver
[charles. weaver@deq. nc. gov] .
Sincerely,
Douglas E. Dowden
Industrial NPDES Permitting Supervisor
Division of Water Resources
ec: NPDES Unit (Laserfiche)

Permit NCO025879
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby revoked. As of this
permit issuance, any previously issued permit bearing this number is no longer effective. Therefore, the exclusive authority
to operate and discharge from this facility arises under the permit conditions, requirements, terms, and provisions included
herein.
The Town of Robbinsville
is hereby authorized to:
1. Continue to operate an existing 0.63 MGD wastewater treatment facility that includes the
following components:
• Mechanical bar screen
• Influent pump station
• Flow splitter device [divides flow 0.315/0.315 MGD]
• Two (2) anoxic basins (in parallel)
• Two (2) aerobic basins (in parallel)
• Two (2) post -anoxic basins (in parallel)
• Two (2) clarifiers (in parallel)
• Aerated sludge holding basin w/ sludge pump, belt filter press, and lime feed
• Two (2) tertiary filters (in parallel)
• UV disinfection
• Continuous flow measurement flume
• Appurtenant piping to Outfall 001
This facility is located at the Robbinsville Sewer Plant, SW corner of Old Hwy 129 and Knight
Street, Robbinsville.
Discharge from said treatment works via Outfall 001, as located on the attached map, into Long
Creek [stream segment 2-190-4-(5)], a waterbody currently classified C-Trout within subbasin
04-04-04 [HUC: 060102040106] of the Little Tennessee River Basin, and
2. After submitting to DWR a request to expand wastewater treatment facilities to 0.85 MGD, and
after receiving DWR's Authorization to Construct permit, and after submitting an Engineer's
Certification Form confirming that new facilities have been constructed in accord with this permit
and said Authorization to Construct, then
3. Discharge via relocated Outfall 001, as identified on the attached map, into the Cheoah River
[stream index 2-190-4-(5)], a waterbody currently classified C-Trout within subbasin 04-04-04
[HUC: 060102040106] of the Little Tennessee River Basin.
Page 2 of 7

Permit NCO025879
Part I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (0.63 MGD)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
Biological WPCS Class WW-3 per 15A NCAC 08G .0302
Beginning on the effective date and lasting until DWR approval of flow expansion, the Permittee is
authorized to discharge via Outfall 001 into Long Creek. Such discharge shall be limited, monitored, and
reported 1 by the Permittee as specified below:
EFFLUENT CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
eDMR Codes
Monthly
Weekly
Daily
Maximu
Measurement
Sample
Sample
Average
Average
g
In
Frequency
Fre9 Y
Type e
Flow
Flow
50050
0.63 MGD
Continuous
Recording
Influent or
Effluent
Total Suspended Solids 3
C0530
30.0 mg/L
45.0 mg/L
3/Week
Composite
Influent &
Effluent
BOD, 5-day (20°C)3
C0310
5.0 mg/L
7.5 mg/L
3/Week
Composite
Influent &
Effluent
pH [Standard Units]
00400
Not < 6.0 or > 9.0
3/Week
Grab
Effluent
Total Residual Chlorine 4
50060
28 ug/L4
3/Week
Grab
Effluent
Fecal Coliform
(Geometric mean)
31616
200/100 mL
400/100 mL
3/Week
Grab
Effluent
Turbidity
00070
Monitor and Report
Weekly
Grab
U & D
Dissolved Oxygen
00300
Monitor and Report
Weekly
Grab
U & D
Temperature (°C)
00010
Monitor and Report
Weekly
Grab
U & D
Ammonia (NH3 as N)
[April 1 - October 311
C0610
1.0 mg/L
3.0 mg/L
Weekly
Composite
Effluent
Ammonia (NH3 as N)
[November 1 - March 31 ]
C0610
2.0 mg/L
6.0 mg/L
Weekly
Composite
Effluent
Total Nitrogen (TN)5
C0600
45.2 pounds/day
Monthly
Composite
Effluent
[NO2+NO3+TKN]
Annual average
Total Phosphorus (TP) 5
C0655
3.8 pounds/day
Annual average
Monthly
Composite
Effluent
Total Mercury6
COMER
Monitor and Report 6
Once per
Permit Cycle
Grab 6
Effluent
Footnotes:
l . The Permittee shall submit discharge monitoring reports electronically using the Division's eDMR system
[see A. (3.)].
2- U = Upstream; D = Downstream (U&D minimum 100 feet from the outfall)
3. The monthly average effluent BOD-5 and Total Suspended Solids concentrations shall not exceed 15% of
the respective influent value (i.e., 85 % removal required).
4. Total Residual Chlorine (TRC) limits and monitoring apply only if chlorine is added to the waste stream
during treatment processes. The Division shall consider compliant all effluent TRC values reported below
Page 3 of 7

Permit NCO025879
50 µg/L. However, the Permittee shall continue to record and submit all values reported by North Carolina -
certified test methods (including field certified), even if these values are reported below 50 µg/L.
5. TN/TP Annual Average shall reflect the average of composite samples collected Monthly during each
calendar year.
6. Total Mercury shall be monitored using EPA Method 1631 E [see A. (4.)]. The Permittee shall sample
during the last year of the permit cycle and submit results with the application to renew this permit.
Condition: The Permittee shall discharge no floating solids or foam visible in other than trace amounts.
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (0.85 MGD)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
Biological WPCS Class WW-3 per 15A NCAC 08G .0302
Upon receipt of an Engineering Certification Form for flow expansion to 0.85 MGD, the Permittee is
authorized to discharge via relocated Outfall 001 to the Cheoah River. Such discharge shall be
limited, monitored, and reported ' by the Permittee as specified below:
LIMITS
MONITORING REQUIREMENTS
EFFLUENT CHARACTERISTICS
Sample
eDMR Codes
Monthly
Weekl y
Daily
Measurement
Sample
Location
Average
Average
Maximum
Frequency
Type
2
Flow
50050
0.85 MGD
Continuous
Recording
Influent or
Effluent
Total Suspended Solids 3
C0530
30.0 mg/L
45.0 mg/L
3/Week
Composite
Influent &
Effluent
BOD, 5-day (20°C)3
C0310
5.0 mg/L
7.5 mg/L
3/Week
Composite
Influent &
Effluent
pH [Standard Units]
00400
Not < 6.0 or > 9.0
3/Week
Grab
Effluent
Total Residual Chlorine 4
50060
28 ug/1-4
3/Week
Grab
Effluent
Fecal Coliform
(Geometric mean)
31616
200/100 mL
400/100 mL
3/Week
Grab
Effluent
Turbidity
00070
Monitor and Report
Weekly
Grab
U & D
Dissolved Oxygen
00300
Monitor and Report
Weekly
Grab
U & D
Temperature (°C)
00010
Monitor and Report
Weekly
Grab
U & D
Ammonia (NH3 as N)
[April 1 — October 31 ]
C0610
16.4 mg/L
47.4 mg/L
Weekly
Composite
Effluent
Ammonia (NH3 as N)
[November 1 — March 31 ]
C0610
Monitor and Report
Weekly
Composite
Effluent
Total Nitrogen (TN)5
C0600
45.2 pounds/day
Monthly
Composite
Effluent
[NO2+NO3+TKN]
Annual average
Total Phosphorus (TP)5
C0655
6.8 pounds/day
Annual average
Monthly
Composite
Effluent
Total Mercury 6
COMER
Monitor and Report 6
Once per
Permit Cycle
Grabs
Effluent
(Footnotes on next page)
Page 4 of 7

Permit NCO025879
Footnotes:
I . The Permittee shall submit discharge monitoring reports electronically using the Division's eDMR system
[see A. (3.)].
2. U = Upstream; D = Downstream (U&D minimum 100 feet from the outfall)
3. The monthly average effluent BOD-5 and Total Suspended Solids concentrations shall not exceed 15% of
the respective influent value (i.e., 85 % removal required).
4. Total Residual Chlorine (TRC) limits and monitoring apply only if chlorine is added to the waste stream
during treatment processes. The Division shall consider compliant all effluent TRC values reported below 50
µg/L. However, the Permittee shall continue to record and submit all values reported by North Carolina
certified test methods (including field certified), even if these values are reported below 50 µg/L.
5. TN/TP Annual Average shall reflect the average of composite samples collected Monthly during each
calendar year.
6. Total Mercury shall be monitored using EPA Method 1631 E [see A. (4.)]. The Permittee shall sample
during the last year of the permit cycle and submit results with the application to renew this permit.
Condition: The Permittee shall discharge no floating solids or foam visible in other than trace amounts.
A. (3.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS
[G.S. 143-215.1(b)]
Federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and program
reports. The final NPDES Electronic Reporting Rule was adopted and became effective on December 21, 2015.
NOTE: This special condition supplements or supersedes the following sections within Part II of this permit
(Standard Conditions for NPDES Permits):
• Section B. (11.
• Section D. (2.)
• Section D. (6.)
• Section E. (5.)
Signatory Requirements
Reporting
Records Retention
Monitoring Reports
1. Reportine Requirements [Supersedes Section D. (2.) and Section E. (5.) (a)]
The permittee shall report discharge monitoring data electronically using the NC DWR's Electronic
Discharge Monitoring Report (eDMR) internet application.
Monitoring results obtained during the previous month(s) shall be summarized for each month and
submitted electronically using eDMR. The eDMR system allows permitted facilities to enter monitoring
data and submit DMRs electronically using the internet. The eDMR system may be accessed at:
https:Hdeq.nc.gov/about/divisions/water-resources/edmr.
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility being
physically located in an area where less than 10 percent of the households have broadband access, then a
temporary waiver from the NPDES electronic reporting requirements may be granted and discharge
monitoring data may be submitted on paper DMR forms (MR 1, 1. 1, 2, 3) or alternative forms approved by
the Director. Duplicate signed copies shall be submitted to the following address:
NC DEQ / Division of Water Resources / Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Page 5 of 7

Permit NCO025879
Raleigh, North Carolina 27699-1617
See "How to Request a Waiver from Electronic Reporting" section below.
Monitoring results obtained during the previous month(s) shall be summarized for each month and reported
via the eDMR system no later than the last calendar day of the month following the completed reporting
period. Regardless of the submission method, the first DMR is due on the last day of the month following
the issuance of the permit or in the case of a new facility, on the last day of the month following the
commencement of discharge.
Starting on December 21, 2025, the permittee must electronically report the following compliance
monitoring data and reports, when applicable:
• Sewer Overflow/Bypass Event Reports;
• Pretreatment Program Annual Reports; and
• Clean Water Act (CWA) Section 316 (b) Annual Reports.
The permittee may seek an electronic reporting waiver from the Division (see "How to Request a Waiver
from Electronic Reporting" section below).
2. Electronic Submissions
In accordance with 40 CFR 122.41(1)(9), the permittee must identify the initial recipient at the time of each
electronic submission. The permittee should use the EPA's website resources to identify the initial recipient
for the electronic submission.
Initial recipient of electronic NPDES information from NPDES-regulated facilities means the entity (EPA or
the state authorized by EPA to implement the NPDES program) that is the designated entity for receiving
electronic NPDES data [see 40 CFR 127.2 (b)].
EPA plans to establish a website that will also link to the appropriate electronic reporting tool for each type
of electronic submission and for each state. Instructions on how to access and use the appropriate electronic
reporting tool will be available as well. Information on EPA's NPDES Electronic Reporting Rule is found
at: https://www.federalregister.gov/documents/2015110/22/2015-24954/national-pollutant-discharge-
elimination-system-npdes-electronic-reporting
Electronic submissions must start by the dates listed in the "Reporting Requirements" section above.
3. How to Request a Waiver from Electronic Reporting
The permittee may seek a temporary electronic reporting waiver from the Division. To obtain an electronic
reporting waiver, a permittee must first submit an electronic reporting waiver request to the Division.
Requests for temporary electronic reporting waivers must be submitted in writing to the Division for written
approval at least sixty (60) days prior to the date the facility would be required under this permit to begin
submitting monitoring data and reports. The duration of a temporary waiver shall not exceed 5 years and
shall thereupon expire. At such time, monitoring data and reports shall be submitted electronically to the
Division unless the permittee re -applies for and is granted a new temporary electronic reporting waiver by
the Division. Approved electronic reporting waivers are not transferrable. Only permittees with an
approved reporting waiver request may submit monitoring data and reports on paper to the Division for the
period that the approved reporting waiver request is effective.
Information on eDMR and the application for a temporary electronic reporting waiver are found on the
following web page:
http://deq.nc.gov/about/divisions/water-resources/edmr
Page 6 of 7

Permit NCO025879
4. SiEnatory Requirements [Supplements Section B. (11.) (b) and Supersedes Section B. (11.)
All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II,
Section B. (11.) (a) or by a duly authorized representative of that person as described in Part II, Section B.
(11.) (b). A person, and not a position, must be delegated signatory authority for eDMR reporting purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user account
and login credentials to access the eDMR system. For more information on North Carolina's eDMR
system, registering for eDMR and obtaining an eDMR user account, please visit the following web page:
http://deq.nc.gov/about/divisions/water-resources/edmr
Certification. Any person submitting an electronic DMR using the state's eDMR system shall make the
following certification [40 CFR 122.22]. NO OTHER STATEMENTS OF CERTIFICATION WILL BE
ACCEPTED:
"I certify, under penalty of law, that this document and all attachments were prepared under my direction or
supervision in accordance with a system designed to assure that qualified personnel properly gather and
evaluate the information submitted. Based on my inquiry of the person or persons who manage the system,
or those persons directly responsible for gathering the information, the information submitted is, to the best
of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fines and imprisonment for knowing violations. "
5. Records Retention [Supplements Section D. (6.)]
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR submissions.
These records or copies shall be maintained for a period of at least 3 years from the date of the report. This
period may be extended by request of the Director at any time [40 CFR 122.41 ].
A. (4.) EFFLUENT MERCURY - ANALYSIS AND REPORTING
[G.S. 143-215.1(b)]
The Permittee shall provide one (1) effluent mercury sample and analysis using clean EPA Method
1631 E, the analytical results to be included as attachment to the next permit renewal application.
Mercury shall be sampled and analyzed during the last year of this permit cycle. Any additional
effluent mercury analyses conducted during this permit cycle shall also be submitted with the renewal
application.
If the minimum mercury analysis is not provided with the application, DWR shall consider the
Permittee non -compliant with the permit, and DWR may return the application as incomplete.
Page 7 of 7