NC0087670_Draft Permit_20240416

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
Mr. Cody Edwards
Currituck County
734 Ocean Trail
Corolla, North Carolina 27927
Dear Permittee:
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NORTH CAROLINA
Environmental Quality
April 16, 2024
Subject: Draft NPDES Permit NCO087670
Southern Outer Banks Water System WTP
Grade I Physical Chemical WPCS
Currituck County
The Division has reviewed your request to renew the subject permit. Enclosed with this letter is a copy
of the draft permit for your facility. Please review this draft carefully to ensure your thorough
understanding of the information, conditions, and requirements it contains.
The draft permit includes the following significant changes from the existing permit:
➢ Updated the maximum, monthly average wastewater discharge on the Supplement to Permit
Cover Sheet.
➢ Added the chemical additives list at the water treatment plant to the Supplement to Permit Cover
Sheet.
➢ Added the facility grade to Section A. (L).
➢ Updated eDMR parameter codes on the effluent table in Section A. (L).
➢ Updated footnotes in the effluent table in Section A. (L).
➢ Updated Whole Effluent Toxicity testing language in Part I. A. (2).
➢ Updated eDMR language for electronic data submission in Part L A. (3).
➢ Updated the map.
The NPDES standard conditions (Parts II, III, and IV) that are a part of the permit are not included in
this draft document (cover, map, and Part I). The conditions are the same as in your current permit
except that agency and division names have been updated. The latest version is available at
https://bit.ly/3k5NFaL and can be viewed online or downloaded as a PDF file.
With this notification, the Division will solicit public comment on this draft permit by publishing a
notice in newspapers having circulation in the general Currituck County area, per EPA requirements.
Please provide your comments, if any, to me at the e-mail address below no later than 30 days
after receiving this draft permit.
Following the 30-day public comment period, the Division will review all pertinent comments and take
appropriate action prior to issuing a final permit.
If you have questions concerning the draft, please contact me at caroline.robinsonAdeq.nc.gov.
North Carolina Department of Environmental Quality I Division of Water Resources
D E Q 512 North Salisbury Street 1 1617 Mail Service Center I Raleigh, North Carolina 27699-1617
NORTH CAROLINA 919.707.9000
DeperlmeM ut Emlmnwiftl Duali�

Page 2 of 2
NPDES Permit NC0087670
Sincerely,
Environmental Specialist II
NPDES Compliance and Expedited Permitting
cc: NPDES Files
Washington Regional Office
Aquatic Toxicology Unit
Operator Certification Program

NPDES Permit NCO087670
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
NPDES
In compliance with the provisions of North Carolina General Statute 143-215.1, other lawful standards
and regulations promulgated and adopted by the North Carolina Environmental Management
Commission, and the Federal Water Pollution Control Act, as amended,
Currituck County
is hereby authorized to discharge wastewater from a facility located at the
Southern Outer Banks Water System WTP
734 Ocean Trail (Route 12)
Corolla
Currituck County
to receiving waters designated as the Atlantic Ocean (downstream of the Pasquotank River Basin) in
accordance with effluent limitations, monitoring requirements, and other conditions set forth in Parts I, II,
III, and IV hereof.
The permit shall become effective
This permit and the authorization to discharge shall expire at midnight on June 30, 2029.
If the permittee intends to continue to discharge at the facility beyond the term of this permit, a renewal
application must be submitted no later than January 1, 2029 (180 days before the expiration of this
permit).
Signed this day
John E. Hennessy, Section Chief Regional Operations
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 8

NPDES Permit NCO087670
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.
Currituck County
is hereby authorized to:
1. Continue to operate a wastewater treatment and disposal system applying Reverse -Osmosis /
Greensand /Ion -Exchange technology, in support of potable -water production from
groundwater sources with a design potable flow rate of 3.09 MGD and a maximum monthly
average wastewater discharge of approximately 1.02 MGD. Water and wastewater treatment
includes the following components:
• two (2) each influent settling / equalization (EQ) basins for raw water from
different sources
• dual (2) treatment trains
o reverse osmosis (RO) for deep -well source water
o greensand / ion -exchange (IO) for shallow -well source water
• wastewater blending tank [receives effluent from both trains]
• disinfection facilities (chlorination and dechlorination)
• final effluent sampling port
• appurtenant piping to outfall
• dual (2) effluent diffusers (ocean discharge)
Chemical Additives
• Calcium Bisulfate
• Sodium Hypochlorite
These facilities located at the Currituck County Outer Banks Water System, south of Corolla, 734 Ocean
Trail (Route 12), in Currituck County, and
2. Discharge from said treatment works at a location specified on the attached map, via Outfall 001,
into the Atlantic Ocean [Stream Index 99-(7)], a waterbody currently classified SB within
subbasin 03-01-54 [HUC: 030102051702] of the Pasquotank River Basin.
Page 2 of 8

NPDES Permit NCO087670
PART I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[ NCAC 02B 0400 et seq. and 02B.0500 et seq.]
Grade 1 Physical Chemical WPC [15A NCAC 08G. 0306]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge via Outfall 001. Such discharges shall be limited, monitored and
reported' by the permittee as specified below:
EFFLUENT CHARACTERISTICS
(PARAMETER CODES)
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location
Flow (MGD)
50050
Monitor & Report
Continuous
Recording
Effluent
Total Suspended Solids (mg/L)
C0530
30.0 mg/L
45.0 mg/L
Weekly
Composite
Effluent
Total Residual Chlorine (µg/L)
50060
13 µg/L 2
Weekly
Grab
Effluent
pH (s.u.)
00400
Not < 6.8 or > 8.5 s. u.
Weekly
Grab
Effluent
Turbidity (NTU)
00070
Monitor & Report
2/Month
Grab
Effluent
Conductivity (µmhos/cm)
00094
Monitor & Report
2/Month
Composite
Effluent
Salinity (ppth)
00480
Monitor & Report
2/Month
Composite
Effluent
Total Dissolved Solids (mg/L)
70295
Monitor & Report
2/Month
Composite
Effluent
Ammonia (NH3_N) (mg/L)
C0610
Monitor & Report
Monthly
Composite
Effluent
Total Nitrogen (TN) (mg/L)
C0600
Monitor & Report
Quarterly
Composite
Effluent
Total Phosphorus (TP) (mg/L)
C0665
Monitor & Report
Quarterly
Composite
Effluent
Whole Effluent Toxicity3
TGP3E
Monitor & Report
Quarterly
Composite
Effluent
Footnotes:
1. The Permittee shall submit monthly Discharge Monitoring Reports (DMRs) electronically using the Division's
eDMR system [see Section A. (3)].
2. Monitoring is required only if chlorine and/or chlorine derivatives are added to the backwash and/or rinse water
used regenerate softeners, or added in the effluent. The Division shall consider all effluent TRC values reported
below 50 µg/L to be in compliance with the permit. However, the Permittee shall continue to record and submit
all values reported by a North Carolina certified laboratory (including field certified), even if these values fall
below 50 µg/L.
3. Whole Effluent Toxicity (WET) Test, Chronic for saltwater (Mysidopsis bahia) Pass/Fail at 0.67% is required
in the months of January, April, July, and October [see Section A. (2.)].
THE PERMITTEE SHALL DISCHARGE NO FLOATING SOLIDS OR FOAM OTHER THAN
TRACE AMOUNTS.
Page 3 of 8

NPDES Permit NCO087670
A. (2.) CHRONIC TOXICITY PASS/FAIL PERMIT MONITORING (QUARTERLY)
[ 15A NCAC 02B .0200] [15A NCAC 02B .05001
The effluent discharge shall at no time exhibit observable inhibition of growth or significant mortality to
Mysidopsis Bahia at an effluent concentration of 0.67% [established by diffuser modeling].
The permit holder shall perform at a minimum, quarterly monitoring using procedures described below
to establish compliance with the permit condition. The tests will be performed during the months of
January, April, July, and October. 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. The test procedure will be based on EPA Method 1007.0, Mysid,
Mysidopsis Bahia, Survival, Growth, and Fecundity Test, as described in Short -Term Methods for
Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms,
Third Edition, EPA-821-R-02-014. The procedure will be performed as written with the following
exceptions:
• The test treatments will consist of a control and a 0.67% effluent concentration.
• Mortality for pass/fail tests will be evaluated using the t test described in Section 11.3 in
Methods for Measuring the Acute Toxicity of Effluents to Freshwater and Marine
Organisms, Fifth Edition. EPA-821-R-02-012, October 2002, applying an alpha level of
0.05.
• The growth endpoint for pass/fail tests will be determined using Appendix G of Short -
Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to
Marine and Estuarine Organisms, Third Edition, EPA-821-R-02-014, October 2002,
applying an alpha level of 0.01.
• Mortality and growth endpoints for multiple -concentration tests will be determined using
hypothesis testing as described in EPA Method 1007.0, Mysid, Mysidopsis Bahia,
Survival, Growth, and Fecundity Test, as described in Short -Term Methods for Estimating
the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine
Organisms, Third Edition, EPA-821-R-02-014, October 2002.
• Fecundity will not be evaluated.
All toxicity testing results required as part of this permit condition will be entered electronically using the
Division's eDMR system for the months in which tests were performed. For pass/fail results, report using
the parameter code TGP3E. Additionally, DWR Form AT-4 (original) is to be sent to the following
address:
North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, NC 27699-1621
Or, results can be sent to the email, ATForms.ATB(&,,deq.nc.gov.
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30
days after the end of the reporting period for which the report is made.
Page 4 of 8

NPDES Permit NCO087670
Test data shall be complete, accurate, include all supporting chemical/physical measurements and all
concentration/response data, and be certified by laboratory supervisor and ORC or approved designate
signature. Total residual chlorine of the effluent toxicity sample must be measured and reported if
chlorine is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is
required, the permittee will complete the information located at the top of the aquatic toxicity (AT) test
form indicating the facility name, permit number, pipe number, county, and the month/year of the report
with the notation of "No Flow" in the comment area of the form. The report shall be submitted to the
Water Sciences Section at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring
will be required during the following month. Upon submission of a valid test, this monthly test
requirement will revert to quarterly in the months specified above. Should any test data from this
monitoring requirement or tests performed by the North Carolina Division of Water Resources indicate
potential impacts to the receiving stream, this permit may be re -opened and modified to include alternate
monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control
organism survival, minimum control organism growth, and appropriate environmental controls, shall
constitute an invalid test and will require immediate follow-up testing to be completed no later than the
last day of the month following the month of the initial monitoring.
USE OF A DIFFERENT TEST ORGANISM
The permittee may request the use of a different test organism upon documentation that the alternate test organism
would provide an equal or greater level of protection and is appropriate based on the characteristics of the discharge
and receiving stream. Such documentation would consist of one of the following:
For saltwater classified streams, a fathead minnow may be assigned as the acute testing species if the
salinity of the receiving stream at the point of discharge is <5 ppt throughout the tidally influenced
cycle. This determination may be based on the best professional judgment of DWR staff or data
collection provided by the permittee and approved by DWR staff. This evaluation should include
vertical profiles of salinity/conductivity measurements at both high tide and low tide over several 24-
hr cycles.
2. Three consecutive "side -by -side" tests with results indicating that the alternate test organism is as
or more sensitive to the facility's effluent. Each test series would consist of two separate toxicity
tests conducted on the same sample of effluent with the length of exposure specified by the permit,
the only difference between the tests being the organism used.
3. An alternate plan developed by the permittee and approved by the Aquatic Toxicology Unit that
demonstrates an equal level of protection is offered by the test organism.
For items 2 and 3, it must also be demonstrated that viable and standardized culture techniques are available for that
organism and standardized testing methodologies have been developed and validated. This demonstration should
meet guidance provided by EPA in Section 6 of EPA-821-R-02-012, "Short Term Methods for Estimating the Acute
Toxicity of Effluents and Receiving Waters to Freshwater Organisms, Fifth Edition 2002."
Requests to use a different test organism and supporting documentation should be sent to North Carolina Division
of Water Resources, Water Sciences Section (at the address listed above).
Page 5 of 8

NPDES Permit NCO087670
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. Reporting 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://deq.ne.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
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.
Page 6 of 8

NPDES Permit NC0087670
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: hgps://www.federalre ig ster.gov/documents/2015/10/22/2015-
24954/national-pollutant-discharge-elimination-system-npdes-electronic-reporting-rule
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:
hltp:Hdeq.ne.gov/about/divisions/water-resources/edmr
4. Signatory Requirements [Supplements Section B. (11.) (b) and Supersedes Section B. (11.) (d)1
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
Page 7 of 8

NPDES Permit NC0087670
eDMR system, registering for eDMR and obtaining an eDMR user account, please visit the following
web page:
hqp:Hdeq.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 ].
Page 8 of 8

Outer Banks _
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Approximate Facility °
Location
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Outfa11001
(discharge via dual (2) diffusers -�
buried —250 feet offshore)
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ChurEnVI
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NCO087670 - Southern Outer Banks Water
System WTP
Currituck County
Receiving Stream: Atlantic Ocean [99-(7)] Stream Class: SB
Drainage Basin: Pasquotank (downstream) Sub -Basin: 03-01-54
Latitude: 360 18' 55" N Long: 75° 48' 15" W
State Grid/Quad: B35SE / Mosey Islands, NC
Facility
Location
not to scale
Currituck County
./VQi Map not to scale