NC0085707_Fact Sheet_20210311

DEQ/DWR
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NC0085707
Facility Information
Applicant/Facility Name:
Cape Hatteras WTP
Applicant Address:
600 Mustian Street; Kill Devil Hills, NC 27948
Facility Address:
50225 Water Association Road; Frisco, NC
Permitted Flow
Model determined an IWC = 6.5% based on a design flow of 0.743 MGD
Type of Waste:
Design RO reject water/treated anion/sand filter regen/backwash (10% sand
filter backwash wastewater)
Facility/Permit Status:
Class I/Active; renewal
County:
Dare County
Miscellaneous
Receiving Stream:
Pamlico Sound
Stream Classification:
SA, HQW
Subbasin:
03-01-55
Index No.
30-22
Drainage Area (mi2):
Modeled (tidal)
303(d) Listed?
No
Summer 7Q10 (cfs)
Modeled (tidal)
Regional Office:
Washington
Winter 7Q10 (cfs):
Modeled (tidal)
State Grid / USGS Quad:
F36SE Buxton, NC
30Q2 (cfs)
Modeled (tidal)
HUC:
03020105
Average Flow (cfs):
Modeled (tidal)
Permit Writer:
Emily DelDuco
IWC (%):
Model IWC = 6.5%
Date:
Dec 9 2020
BACKGROUND
Dare County operates a multi process drinking water treatment (WTP) facility that serves the
Outer Banks Cape Hatteras area. Twenty-three wells provide the raw water for the water
treatment plant. The facility discharges a combined wastewater made up of reverse osmosis
reject water and treated wastewater from two anion exchange systems and three pressure sand
filters. During the summer, demand is high and the facility produces approximately 1.4 MGD of
potable water with the anion exchange systems and pressure sand filters operating more
frequently and having a wastewater discharge once every 2-3 weeks. During the winter, potable
water demand decreases to about 0.4 MGD and the anion exchange systems and pressure sand
filters are seldom used.
The reject and backwash wastewaters are discharged via a submerged diffuser into Pamlico
Sound, a class SA; HQW water in the Pasquotank River Basin. These receiving waters are not on
the 2018 303(d) list for impaired waters.
HISTORY
This facility was constructed and originally permitted in 1996 as a new discharge into a HQW
receiving waterbody. As a new discharger into a class SA, HQW receiving stream, water quality
standards (WQS) are more stringent and specific chemicals such as toxicants have standards
equal to half of the saltwater WQSs. The Total Suspended Solids limit for a new discharge to
HQW receiving waters is 20 mg/1.
A dye study was performed in July 2001 and used to (1) characterize the diffuser water column
mixing profile and (2) to provide model data to define the Instream Wastewater Concentration
(IWC). Based on the model an IWC of 6.5% was determined using an average discharge
flowrate of 0.743 MGD. In the 2004 permit renewal the required toxicity test was changed from
Fact Sheet
NPDES NC0085707
Page 1 of 4

a limited acute test at an 80% effluent concentration to a chronic test using Mysid shrimp at a
6.5% effluent concentration.
In March 2009, the Reasonable Potential Analysis performed to develop permit renewal
limitations did not take into account the modelled dilution or the HQW halved standards for
metals. The issued permit included new non-HQW, SA effluent limits and new monitoring
requirements for Total Chromium, Total Nickel, and Total Selenium. However, if HQW-based
limits had been applied in the RPA, Total Chromium, Total Nickel, and Total Selenium would
have still been the only evaluated parameters that showed potential to exceed the HQW limits.
The chronic 6.5% effluent concentration toxicity test and the more stringent TSS standards for
HQW waters were maintained. Other monitoring parameters were assigned or amended based on
the WTP Strategy.
The March 2009 permit renewal also contained a footnote that allowed the permittee to petition
for re-evaluation of the newly added WQS limits and measurement frequencies for Total
Chromium, Total Nickel, and Total Selenium after a minimum of twelve months of new data. In
May 2009 a written petition to (1) re-evaluate the new limits and to (2) re -apply the IWC of
6.5% in the RPA was received. The permittee stated that the discharge flow had not changed nor
had the quality of the well water changed since start up. The petition also requested that the
monitoring frequencies be returned to the 2004 levels.
During May 2009 and June 2009 the permittee split samples between two certified labs and all
the data was used in the re-evaluation.
In Sept. 2010 a modified permit was issued and limitations and monitoring were developed using
HQW saltwater standards and an IWC of 6.5%. The flow run chart confirmed that the
experienced discharge flow was about the same year to year and had not exceeded the dye study
flow. Therefore, the average flow of 0.743 MGD used in the model was used in the RPA. Based
on DMR data from June 2009 to June 2010 results suggested reasonable potential for the facility
to discharge Total Nickel and Total Selenium in excess of defined HQW-WQS. As a result, new
Total Nickel and Total Selenium HQW-based monthly average maximum limits and daily
maximum limits were added to the permit. Total Selenium limits were corrected and listed as
monthly average and daily maximum limitations. Total Chromium was removed since it did not
show reasonable potential to violate standards. Monitoring for Total Copper, Total Silver, and
Total Zinc were reduced to quarterly to coincide with toxicity tests.
The 2015 renewal removed total nickel and total zinc monitoring based on lack of reasonable
potential to exceed water quality standards. Silver, selenium, and chromium all remained
undetected and were removed from monitoring requirements during renewal.
PROCESS
Well water is pumped through replaceable cartridge filters and continues through two reverse
osmosis units. Reject wastewater from the reverse osmosis units is constantly discharged and
blended with wastewaters from the two anion exchange systems and three pressure sand filters
The anionic treatment systems treat water from 19 wells and intermittently backwash once every
2-3 weeks in the summer and at most once a week in the winter. Potable water treated in the
anionic exchange units flow through the pressure sand filters. The brine regenerate from the
anionic exchange units are combined with the sand filter backwash in a 240,000 gallon holding
settling basin. Wastewaters from the settling basin are blended with the RO reject wastewater
prior to discharge. The mixed wastewaters discharge through a submerged diffuser
approximately 100 feet off shore into Pamlico Sound. Other than brine and a scale inhibitor no
other chemicals have the potential to be discharged.
Fact Sheet
NPDES NC0085707
Page 2 of 4

EXISTING DISCHARGE CHARACTERISTICS
Flow (MGD) May 2016-Nov 2020
Year Mean Min Max N
2016 0.52 0.20 0.72 245
2017 0.46 0.13 0.96 365
2018 0.47 0.11 0.70 365
2019 0.51 0.11 0.98 365
2020 0.52 0.18 0.70 335
Maximum monthly average flow in past 3.5 years (Qw): 0.70 MGD
Effluent data May 2016-Nov 2020
Parameter
00010 - Temperature, Water Deg. Centigrade
00094 - Conductivity
00300 - Oxygen, Dissolved (DO)
00400 - pH
00480 - Salinity
00530 - Solids, Total Suspended
00610 - Nitrogen, Ammonia Total (as N)
01042 - Copper, Total (as Cu)
50050 - Flow, in conduit or thru treatment plant
70295 - Solids, Total Dissolved
CO530 - Solids, Total Suspended - Concentration
CO600 - Nitrogen, Total - Concentration
CO610 - Nitrogen, Ammonia Total (as N)
CO665 - Phosphorus, Total (as P) - Concentration
Mean Min Max N
20.28 18.80 22.10 111
37381 17100 73700 110
6.08 3.79 6.51 111
7.46 6.86 7.50 240
23.44 10.00 31.80 110
8.20 7.50 8.60 4
10.32 10.32 10.32 1
8.79 0.01 18.00 18
0.49 0.11 0.98 1675
27824 21620 36380 110
8.53 2.50 21.00 239
10.48 6.22 17.22 18
9.95 8.62 11.74 55
0.18 0.04 0.61 18
COMPLIANCE
Effluent data was reviewed from May 2015 to Aug. 2020 and no limit violation has been
documented. No enforcements have taken place since the last renewal. The last routine
inspection was performed on September 13, 2017 and the facility evaluation rating was
satisfactory.
This facility has not failed any toxicity tests in the last 5 years.
INSTREAM MONITORING
Upstream
Parameter Mean Minl Max N
00010 - Temperature, Water Deg. Centigrade 19.81 1.70 29.00 109
00094 - Conductivity 30149 11800 44300 108
00300 - Oxygen, Dissolved (DO) 6.53 6.01 9.11 109
00400 - pH 7.54 7.17 8.34 109
00480 - Salinity 18.95 6.73 31.80 108
Fact Sheet
NPDES NC0085707
Page 3 of 4

Downstream
Parameter Mean Min Max N
00010 - Temperature, Water Deg. Centigrade 19.73 2.40 29.10 109
00094 - Conductivity 30344 11800 44000 108
00300 - Oxygen, Dissolved (DO) 6.53 6.03 9.11 109
00400 - pH 7.54 7.10 8.34 109
00480 - Salinity 18.86 6.73 28.40 108
This facility samples for pH, temperature, dissolved oxygen, salinity, and conductivity about 50
feet north and south of the outfall. Instream data was reviewed for the period of May 2016 — Nov
2020. The effluent from this facility did not appear to impact pH, temperature, dissolved oxygen,
or salinity. The high conductivity of the RO wastewaters did appear to raise the conductivity
concentrations slightly in the downstream samples.
Per the 2012 WTP permitting strategy, DO monitoring can be removed if in -stream standards are
being met. In the past 6 months, the effluent DO has frequently dipped below 5 mg/l. Although
this has not impacted instream DO, monitoring will remain in place to be re-evaluated during the
next renewal.
PERMITTING STRATEGY
A Reasonable Potential Analysis was performed on copper using effluent data from May 2015
through Oct. 2020. The modelled design flow of 0.743 MGD at a dilution of 6.5% were used in
the RPA. Toxicant standards were halved to assess limitations against predicted values.
• Copper showed no reasonable potential to violate WQS, however, the predicted
maximum is greater than half of the allowable concentration, so quarterly monitoring will
be maintained.
SUMMARY OF CHANGES
➢ The language in section A.(3) has been updated to be consistent with the finalization of
federal requirements for electronic reporting.
➢ The language in section A.(2) has been updated with new electronic reporting methods
➢ HUC and Stream Index were added to the supplement to cover page
➢ The outfall map was updated
➢ Instream and effluent temperature monitoring were removed from the permit. Temperature
monitoring is no longer a requirement for WTPs.
➢ Footnote 3 of the effluent table previously required copper to be sampled in conjunction
with Chronic Toxicity testing. Concurrent sampling is no longer a requirement, so the
footnote has been removed.
➢ Turbidity monitoring (no limit) has been added to the effluent monitoring table in section
A.(1.). Turbidity monitoring is required for all WTPs.
NPDES DIVISION CONTACT
If you have questions regarding any of the above information or on the attached permit, please
contact Emily DelDuco email [e-mail].
NAME: DATE:
Fact Sheet
NPDES NC0085707
Page 4 of 4

Whole Effluent Toxicity Testing and Self Monitoring Summary
Camden County WTP NC0086681/001 County: Camden Region: WARO Basin: PAS50 Jan Apr Jul Oct
Mysd24PF Begin: 3/1/2018 24hr p/f ac monit 90 NonComp: 7Q10: Tidal PF: 0.432 IWC: NA Freq: Q
SOC JOC:
J F M A M J J A S 0 N D
2016 Pass - - Pass - Pass - - Pass -
2017 Pass - - Pass - - Pass - - Pass -
2018 Pass - - Pass - - Pass - - Pass -
2019 Pass - - Pass - - Pass - - Pass -
2020 Pass - - Pass - - Pass - - Pass -
Camp Highlander WWTP NC0033251/001 County: Henderson Region: ARO Basin: FRB03 Jan Apr Jul Oct
Fthd24PF Begin: 4/1/2006 24hr ac p/f lim 90% NonComp: Single 7Q10: 12.7 PF: 0.007 IWC: 0.09 Freq: Q
SOC JOC:
J F M A M J J A S 0 N D
2016 H H - H H
2017 H - - H - - H - - H -
2018 H - - H - - H - - H -
2019 H - - H - - H - - H -
2020 H - - H - - H - - H -
Cape Hatteras Water Assoc. (RO) WTP NC0085707/001 County: Dare Region: WARO
Mysd7dPF Begin: 2/1/2016 Chr monit 6.5% (mysi + NonComp: Single 7010: Tidal
Basin: PA555 Jan Apr Jul Oct
PF:
IWC: 6.5 Freq: Q
SOC JOC:
J F M A M J J A 5 0 N D
2016 Pass - - Pass - - Pass - - Pass -
2017 Pass Pass Pass Pass -
2018 Invalid Pass Pass Pass Pass
2019 Pass - - Pass - Pass - - Pass
2020 Pass - - Pass - >6.5 - - >6.5 (P)
Carillon Building Dewatering System NC0085731/001 County: Mecklenburg
Ceri7dPF Begin: 9/1/2015 Chr Lim: 90% NonComp:
Region: MRO
7010: 0
Basin: CTB34 Mar Jun Sep Dec
PF: 0.031 IWC: 100 Freq: Q
SOC JOC:
J F M A M J J A 5 0 N D
2016 - - Pass - - Pass - - Pass - - Pass
2017 - - Pass - - Pass - - Pass - - Pass
2018 Pass - - Pass - - Pass - - H
2019 Pass Pass Pass Pass - - Pass
2020 - Pass Pass Pass -
Carolina Beach WWTP NC0023256/001 County: New Hanover Region: WIRO Basin: CPF17 Feb May Aug Nov SOC_JOC:
Mysd7dPF Begin: 4/1/2018 Mys7dyPF Chr Lim: 1 + NonComp: Single 7Q10: Tidal PF: 3.0 IWC: NA Freq: Q
J F M A M J J A S
2016 - Pass - - Pass - - Pass -
2017 Pass - - Pass - Pass -
2018 - Pass >100(P) - - Pass >72 - - Invalid Invalid H
2019 - Pass - - Pass - - Pass
2020 - Pass - - Pass - - H >17.9% (P)
0
>72 Pass
N
Pass
Pass >100(P)
Pass
Pass
>17.9% (P)
Leeend: P= Fathead minnow (Pimohales oromelas). H=No Flow (facility is active). s = Solit test between Certified Labs
Page 14 of 121

Table 1. Project Information
Facility Name
WWTP/WTP Class
NPDES Permit
Outfall
Flow, Qw (MGD)
Receiving Stream
Stream Class
7Q10s (cfs)
7Q1Ow (cfs)
30Q2 (cfs)
QA (cfs)
1 Q1 Os (cfs)
CHRONIC DILUITION FACTOR =
Data Source(s)
To apply a Model IWC%: Enter
the "Flow, Qw, (MGD)" and the
"CHRONIC DILUTION FACTOR
=" values and the CHRONIC
IWC% is calculated and
displayed. The CHRONIC IWC%
is automatically applied to
calculate the parameter's
Allowable Cw values both chronic
and acute.
Saltwater RPA 95% Probablitv/95% Confidence
MAXIMUM DATA POINTS = 58
REQUIRED DATA ENTRY
Table 2. Parameters of Concern
❑✓ CHECK IF HQW OR ORW WQS
Cape Hatteras RO WTP
NC0085707
Pamlico Sound
SA; HQW
Modeled, Chronic Dilution Factor defined
Modeled, Chronic Dilution Factor defined
Modeled, Chronic Dilution Factor defined
Modeled, Chronic Dilution Factor defined
CHRONIC IWC% = 6.5
15.3800
Saltwater streams are tidal resulting in all IWC % = 100%.
If an approved model is conducted then a chronic dilution
factor is determined and can be applied to a discharge to
calculate its IWC % . If a stream is classified as a SA or
ORW then its is also classified as a HQW. The appropriate
IWC % must be defined to properly calculate WQS-based
limits.
Par01
Par02
Par03
Par04
Par05
Par06
Par07
Par08
Par09
Par10
Par11
Par12
Par13
Par14
Par15
Par16
Par17
Par18
Par19
Par20
Par21
Par22
Name
WQS
Type Chronic Modifier Acute PQL Units
Arsenic
Aquatic Life
C
36
SW
69
ug/L
Arsenic
Human Health
C
10
HH
ug/L
Cadmium
Aquatic Life
NC
8.9
SW
40.2
ug/L
4 Total Phenolic Compounds
Aquatic Life
NC
300
A
10
ug/L
Chromium VI
Aquatic Life
NC
50.4
SW
1107.8
ug/L
Chromium, Total
Aquatic Life
NC
N/A
SW
N/A
ug/L
Copper
Aquatic Life
NC
3.7
SW
5.8
ug/L
Cyanide
Aquatic Life
NC
1
SW
1
10
ug/L
Lead
Aquatic Life
NC
8.5
SW
220.8
ug/L
Mercury
Aquatic Life
NC
25
SW
0.5
ng/L
Molybdenum
Human Health
NC
2.0
HH
mg/L
Nickel
Aquatic Life
NC
8.3
SW
74.7
ug/L
Selenium
Aquatic Life
NC
71
SW
ug/L
Silver
Aquatic Life
NC
0.1
SW
2.2
ug/L
Zinc
Aquatic Life
NC
85.6
SW
95.1
ug/L
NOTE: The aquatic life chronic and acute WQS for several metals are calculated based on EPA convers1
see "Diss. SW stds. As TM" for more details and summary of calculated WQS..
85707 Copy of 9595 Final Saltwater RPA 2017,input
1/4/2021

REASONABLE POTENTIAL ANALYSIS - DATA
Copper
Date Data BDL=1/2DL Results
1 7/11/2016 < 10 5 Std Dev. 4.4343
2 10/3/2016 < 10 5 Mean 7.3889
3 1/9/2017 18 18 C.V. 0.6001
4 4/3/2017 < 10 5 n 18
5 7/10/2017 < 10 5
6 10/2/2017 < 10 5 Mult Factor = 1.4100
7 1/8/2018 10 10 Max. Value 18.00 ug/L
8 4/2/2018 < 10 5 Max. Pred Cw 25.38 ug/L
9 7/9/2018 < 10 5
10 10/22/2018 < 10 5
11 1/7/2019 < 10 5
12 4/1/2019 < 10 5
13 7/8/2019 < 10 5
14 10/7/2019 < 10 5
15 1/6/2020 < 10 5
16 4/6/2020 10 10
17 7/6/2020 18 18
18 10/5/2020 12 12
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Values" then "COPY"
. Maximum data
points = 58
85707 Copy of 9595 Final Saltwater RPA 2017,data
Date}

Cape Hatteras RO WTP
NC0085707
Qw (MGD) _
1Q10S (cfs) =
7QIOS (cfs)=
7Q10W (cfs) =
30Q2 (cfs)
Avg. Stream Flow, QA (cfs)_
Receiving Stream:
Saltwater RPA 95% Probablity/95% Confidence
MAXIMUM DATA POINTS = 58
0.74
Modeled, Chronic Dilution Factor defined
Modeled, Chronic Dilution Factor defined
Modeled, Chronic Dilution Factor defined
Modeled, Chronic Dilution Factor defined
Modeled, Chronic Dilution Factor defined
Pamlico Sound
WWTP/WTP Class: PC-1
IWC% @ 1Q10S = 7.760076938
IWC% @ 7Q10S = 6.501950585
IWC% @ 7Q10W = 6.501950585
IWC% @ 30Q2 = 6.501950585
IWC% @ QA = 6.501950585
Stream Class: SA; HQW
Outfall 001
Qw = 0.743 MGD
YOU HAVE DESIGNATED THIS RECEIVING
STREAM AS HQW OR ORW.
PARAMETER
TYPE
(1)
NC STANDARDS OR EPA CRITERIA
PQL
UNITS
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
Chronic
Applied
Standard
Acute
11
# Det. Max Prcd Cw Allowable Cw
Copper
NC
1.85
SW(7Q1Os)
2.9
ug/L
18
5
25.38
Acute: 37.37
_ _ _ _ _ _ _ _ _
Chronic: 28.45
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ - —
No RPA, Predicted Max > 0% of Allowable
Cw - apply Quarterly Monitoring
Page 3 of 3
85707 Copy of 9595 Final Saltwater RPA 2017,rpa
1/4/2021

IWC Calculations
Facility: Cape Hatteras RO WTP
NC0085707
Prepared By: JAG
Enter Design Flow (MGD):
Enter s7Q10 (cfs):
Enter w7Q10 (cfs):
0.743
16.57
16.57
Total Residual Chlorine (TRC)
Daily Maximum Limit (ug/I)
s7Q10 (CFS)
DESIGN FLOW (MGD)
DESIGN FLOW (CFS)
STREAM STD (UG/L)
Upstream Bkgd (ug/I)
IWC (%)
Allowable Conc. (ug/I)
Fecal Coliform
Monthly Average Limit:
(If DF >331; Monitor)
(If DF<331; Limit)
Dilution Factor (DF)
16.57
0.743
1.15165
17.0
0
6.50
262
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/I)
s7Q10 (CFS)
DESIGN FLOW (MGD)
DESIGN FLOW (CFS)
STREAM STD (MG/L)
Upstream Bkgd (mg/I)
IWC (%)
Allowable Conc. (mg/I)
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/I)
w7Q10 (CFS)
200/100m1 DESIGN FLOW (MGD)
DESIGN FLOW (CFS)
STREAM STD (MG/L)
15.39 Upstream Bkgd (mg/I)
IWC (%)
Allowable Conc. (mg/I)
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); capped at 35 mg/I
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis); capped at 35 mg/I
4. BAT for Minor Domestics: 2 mg/I (summer) and 4 mg/I (winter)
5. BAT for Major Municipals: 1 mg/I (year-round)
16.57
0.743
1.15165
1.0
0.22
6.50
12.2
16.57
0.743
1.15165
1.8
0.22
6.50
24.5
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)
NPDES Server/Current Versions/WLA; TB 1/16/2009

THE COASTLAND TIMES
Post Office Box 400
Manteo, North Carolina 27954
IN ACCOUNT WITH
Description
Ad Number
Attorneys placing legal advertising are held responsible for payment.
NORTH CAROLINA
DARE COUNTY
AFFIDAVIT OF PUBLICATION
Before the undersigned, a Notary Public, duly commissioned, qualified, and authorized by law to
administer oaths, personally appeared the undersigned representative who being duly sworn, deposes and
says that he (she) is an employee or other officer authorized to make this affidavit of Outer Banks
Newsmedia, LLC, engaged in the publication of a newspaper known as The Coastland Times, issued and
entered as second class mailing in the Town of Manteo, N.C., in said county and state; that he (she) is
authorized to make this affidavit and sworn statement; and the notice or other legal advertisement, a true
copy of which is attached hereto, was published in The Coastland Times on the following date(s):
And that the said newspaper in wwhich such notice, paper, document or legal advertisement was published
was at the time of each and every such publication, a newspaper meeting all of the requirements and
qualifications of Section 1-597 of the General Statutes of North Carolina and was a qualified newspaper
within the mean1ing of Section 1-597 of the General Statutes of North Carolina.
This the?
, 2021.
Theresa Schnder
(Signature of representative making affidavit)
Sworn to and subscribed before to me this th day of TCu 2021.
12,(
(Notary Public) -2,U
�P� • oTq •Gs'',
▪ ;• My Comm. Expires ;
• 11/13/2024
.i49 •. AUB l.\G •: G
•
•
4;11: .. .. .....
Public Notice
North Carolina Environmental
Management Commission/
NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Notice of Intent to Issue a
NPDES Wastewater Permit
NC0085707 Cape Hatteras
Reverse Osmosis WTP
The North Carolina Environ-
mental Management Com-
mission proposes to issue a
NPDES wastewater discharge
permit to the person(s) listed
below. Written comments re-
garding the proposed permit will
be accepted until 30 days after
the publish date of this notice.
The Director of the NC Division
of Water Resources e(.DWR)
R) may
hold a public g
there be a significant degree
of public interest. Please mail
comments and/or information
requests to DWR at the above
address. Interested persons
may visit the DWR at 512 N.
Salisbury Street, Raleigh, NC
27604 to review information on
file. Additional information on
NPDES permits and this notice
may be found on our website:
http://deq. nc.gov/about/divi-
sions/water-resources/wa-
ter-resou roes -perm itslwastewa-
pubbcnotices orr by calling (919)
707-3601. NPDES Permit Num-
ber NC0085707: Dare County
(600 Mustian Street, Kill Devil
Hills, NC 27948) has requested
renewal of the NPDES permit
for the Cape Hatteras Reverse
iAJTP in Dare County.

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
Dare County
Attn: Patrick Irwin, Utilities Dir.
PO Box 1000
Manteo, NC 27954-1000
Subject: Permit Renewal
Application No. NC0085707
Cape Hatteras Reverse Osmosis WTP
Dare County
Dear Applicant:
NORTH CAROLINA
Environmental Quality
March 19, 2020
The Water Quality Permitting Section acknowledges the March 17, 2020 receipt of your permit renewal application and
supporting documentation. Your application will be assigned to a permit writer within the Section's NPDES WW permitting
branch. Per G.S. 150B-3 your current permit does not expire until permit decision on the application is made.
Continuation of the current permit is contingent on timely and sufficient application for renewal of the current permit. The
permit writer will contact you if additional information is required to complete your permit renewal. Please respond in a
timely manner to requests for additional information necessary to allow a complete review of the application and renewal
of the permit.
Information regarding the status of your renewal application can be found online using the Department of Environmental
Quality's Environmental Application Tracker at:
https:J/deq. nc.gov/permits-requlations/permit-guidancelenvironmental-application-tracker
If you have any additional questions about the permit, please contact the primary reviewer of the application using the
links available within the Application Tracker.
Sinsrely,
JSV;01
Wren Th ford
Administrative Assistant
Water Quality Permitting Section
cc: Central Files w/application
ec: WQPS Laserfiche File w/application
North Caro re Departrrertof Ervrorrrerta Qua t. x I D vsor of Resras=
D_E Q� Wash rgtor Reg ora Dffae 1943 Wash r.gtor S.L.are Pia I Wasr rgtor, North ar: r5 2?EE3
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NPDES PERMIT APPLICATION - SHORT FORM C - WTP
For discharges associated with water treatment plants
Mail the complete application to:
N. C. Department of Environment and Natural Resources
Division of Water Quality / NPDES Unit
1617 Mail Service Center, Raleigh, NC 27699-1617
NPDES Permit Number
NC0085707
If you are completing this form in computer use the TAB key or the up - down arrows to move from one
field to the next. To check the boxes, click your mouse on top of the box. Otherwise, please print or type.
1. Contact Information:
Owner Name Dare County Water Department
Facility Name Cape Hatteras Reverse Osmosis WTP
Mailing Address 600 Mustian Street
City Kill Devil Hills
State / Zip Code NC, 27948
Telephone Number [phone]
Fax Number [phone]
REGF SUED
MAR 17 710
NGUEQIDWRINPDES
e-mail Address [e-mail]
2. Location of facility producing discharge:
Check here if same as above ❑
Street Address or State Road
City
State / Zip Code
County
50225 Water Association Road
Frisco
NC, 27936
Dare
3. Operator Information:
Name of the firm, consultant or other entity that operates the facility. (Note that this is not referring to the
Operator in Responsible Charge or ORC)
Name
Mailing Address
City
State / Zip Code
Telephone Number
Fax Number
4. Ownership Status:
Dare County Water Department
600 Mustian Street
Kill Devil Hills
NC
[phone]
[phone]
Federal ❑ State ❑
Private ❑ Public X
Page 1 of 3 Version 5/2012

NPDES PERMIT APPLICATION - SHORT FORM C - WTP
For discharges associated with water treatment plants
5. Type of treatment plant:
❑ Conventional (Includes coagulation, flocculation, and sedimentation, usually followed by
filtration and disinfection)
X Ion Exchange (Sodium Cycle Cationic ion exchange)
❑ Green Sand Filter (No sodium recharge)
X Membrane Technology (RO, nanofiltration)
Check here if the treatment process also uses a water softener
6. Description of source water(s) (i.e. groundwater, surface water)
Groundwater
7. Describe the treatment process(es) for the raw water:
The treatment train includes: Reverse osmosis (membrane), ion exchange, pressure sand filters,
cartridge filters, settling basin and chlorination.
8. Describe the wastewater and the treatment process(es) for wastewater generated by the
facility:
Combined concentrate wastewaters from reverse osmosis treatment, anion
backwash/regeneration treated water, and pressure sand filter backwash treated water will be
flowed to the discharge via pipeline to a diffuser.
9. Number of separate discharge points: 1
Outfall Identification number(s) 001
10. Frequency of discharge:
Continuous X Intermittent ❑
If intermittent:
Days per week discharge occurs: Duration:
11. Plant design potable flowrate 2_0 MGD
Backwash or reject flow 0.743 MGD
12. Name of receiving stream(s) (Provide a map showing the exact location of each outfall, including
latitude and longitude):
Map is attached.
13. Please list all water treatment additives, including cleaning chemicals or disinfection
treatments, that have the potential to be discharged.
Alum / aluminum sulfate
Yes No X
Page 2 of 3 Version 5/2012

NPDES PERMIT APPLICATION - SHORT FORM C - WTP
For discharges associated with water treatment plants
Iron sulfate / ferrous sulfate
Fluoride Yes No X
Ammonia nitrogen / Chloramines
Yes No X
Yes No X
Zinc -orthophosphate or sweetwater CP1236 Yes No X
List any other additives below:
Scale inhibitor
Citric acid and sodium hydroxide (membrane cleaning chemicals)
14. Is this facility located on Indian country? (check one)
Yes ❑ No X
15. Additional Information:
Provide a schematic of flow through the facility, include flow volumes at all points in
the water treatment process. The plan should show the point[s] of addition for
chemicals and all discharges routed to an outfall [including stormwater].
Schematic is attached.
Solids Handling Plan - The treatment does not produce solids.
16. NEW Applicants
Information needed in addition to items 1-15:
New applicants are highly encouraged to contact a permit coordinator with the
NCDENR Customer Service Center.
Was the Customer Service Center contacted? ❑ Yes ❑ No
Analyses of source water collected
Engineering Alternative Analysis
Discharges from Ion Exchange and Reverse Osmosis plants shall be evaluated using a
water quality model.
17. Applicant Certification
I certify that I am familiar with the information contained in the application and that to the
best of my knowledge and belief such information is true, complete, and accurate.
Patrick Irwin Utilities Director
Print name of Person Signing Title
Signature
North Carolina General Statute 143-215.6 (b)(2) provides that: Any person who knowingly makes any false statement representation, or certification in any application,
record, report, plan, or other document files or required to be maintained under Article 21 or regulations of the Environmental Management Commission implementing that
Article, or who falsifies, tampers with, or knowingly renders inaccurate any recording or monitoring device or method required to be operated or maintained under Article 21
or regulations of the Environmental Management Commission implementing that Article, shall be guilty of a misdemeanor punishable by a fine not to exceed $25,000, or by
imprisonment not to exceed six months, or by both. (18 U.S.C. Section 1001 provides a punishment by a fine of not more than $25,000 or imprisonment not more than 5
years, or both, for a similar offense.)
Page 3 of 3 Version 5/2012

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Latitude: 35°16'00"
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Receiving Stream: Pamlico Sound
Stream Class: SA
Subbasin: 30155
County: Dare
NC0085707
Dare County -Cape
Hatteras Water System
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DARE COUNTY WATER
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HATTERAS TREATMENT
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From: DelDuco, Emily
To: Pat Irwin
Cc: [e-mail]; [e-mail]
Subject: RE: [External] Re: Electronic delivery of NPDES permit - Cape Hatteras WTP
Date: Thursday, March 11, 2021 9:40:00 AM
Attachments: NC0085707 Final Permit 03-2021.pdf
image001.pnq
Thank you for your reply. Please see the attached issued NPDES permit renewal for Cape Hatteras
Reverse Osmosis WTP.
From: Pat Irwin <[e-mail]>
Sent: Thursday, March 11, 2021 8:22 AM
To: DelDuco, Emily <[e-mail]>
Cc: [e-mail]; [e-mail]
Subject: [External] Re: Electronic delivery of NPDES permit - Cape Hatteras WTP
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an
attachment to Report Spam.
Yes, transmittal of documents to Dare County Water in an electronic manner is
acceptable.
Pat
On Wed, Mar 10, 2021 at 12:28 PM DelDuco, Emily <[e-mail]> wrote:
Greetings,
This is in regards to the NPDES wastewater permit for Cape Hatteras Reverse Osmosis WTP
/NC0085707.
In order to provide more convenience, control, and security to our permittees and assist them in
processing their transactions, The Division of Water Resources is currently transitioning towards
electronic correspondence. This will hopefully provide more efficient service to our permittees
and other partners and will allow us to more effectively process and track documents. We are
writing to ask you for your approval of the transmittal of documents related to your permitting and
related activities with the Division in an electronic format. Documents will be emailed to the
appropriate contact person(s) in your organization in a PDF format.
Please respond to me through email with verification that transmittal of your documents in
an electronic manner is acceptable to you. If you have any questions, please feel free to
contact me.
Thank you,

Emily DelDuco
Division of Water Resources
Department of Environmental Quality
919-707-9125
emily.delducoPncdenr.gov
::"Nothing Compares,
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
Mr. Patrick Irwin
Utilities Director
Department of Water
600 Mustian Street
Kill Devil Hills, NC 27948
[phone] (phone)
(252 441-2239 (fax)
www.darenc.com
Email correspondence to and from this address is subject to the North Carolina Public Records Law and
may be disclosed to third parties.