NC0087670_Draft Fact Sheet_20240416

NCDEQ/DWR/NPDES
EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL
NPDES Permit NCO087670
Caroline Robinson/Compliance&Expedited Permitting Unit/caroline.robinsonkdeq.nc. og_v/March 2024
FACILITY INFORMATION
Applicant/Facility Name Currituck County(Cody Edwards, Superintendent)
Southern Outer Banks Water System WTP
Applicant Address 734 Ocean Trail Corolla,NC 27927
Facility Physical Address/Mailing 734 Ocean Trail Corolla,NC 27927
Address
Max.Monthly Avg Flow(MGD) 1.02 MGD
Type of Waste Reverse osmosis reject wastewater, greensand filter backwash,
and ion-exchange wastewater
Facility Class PC-1 County Currituck
Permit Status Renewal Regional Office WaRO
STREAM CHARACTERISTICS
Receiving Stream Atlantic Ocean Stream SB
Classification
Stream Segment 99-(7) Outfall Lat. 360 18' 55"N
7Q10 - Summer(cfs) Tidal Outfall Long. 750 48' 15" W
7Q 10 -Winter(cfs) Tidal Drainage basin Pasquotank River Basin
30Q2 (cfs) Tidal Subbasin 03-01-54
Average Flow(cfs) Tidal HUC 030102051702
IWC (%) 0.67% 303(d)List No
BASIC INFO FOR EXPEDITED PERMIT RENEWAL
Does permit need Daily Max NH3 limits? No
Does permit need TRC limits/footnote? No -Already present in permit.
Does permit have toxicity testing? Yes,Chronic Toxicity P/F Permit Monitoring
Does permit have any Special Conditions? Yes,Chronic Toxicity P/F Permit Monitoring
Does permit have instream monitoring? No
New expiration date: June 30,2029
FACILITY SUMMARY
Southern Outer Banks Water System WTP utilizes two(2) separate treatment trains to produce potable
water from groundwater. One train applies reverse osmosis(RO)to treat deep-well water(yield to 3.050
MGD);the second train combines greensand and ion-exchange(IO)technology to treat raw water from
shallow wells(yield to 1.345 MGD). The Permittee's flow diagram, estimates RO reject at 71%of
discharge. Actual flow average between Feb 2021-March 2024=0.805 MGD [Max= 1.02 MGD; Min=
0.537 MGD]
The Permittee treats wastewaters using duel trains,blends them together, samples the final effluent for
compliance,then discharges to the Atlantic Ocean via Outfall 001 located approximately 250 feet offshore
at Corolla Beach. Discharge terminates at an effluent diffuser consisting of dual 200-foot long,20-slot
wellscreens, each buried approximately 18 feet below the bottom of the ocean floor;modeled by CORMIX
Fact Sheet for Permit Renewal
March 2024-NPDES Permit NCO087670-Page 1

to establish IWC.Approximate annually,RO filter sludge is transported across the street to the local
WWTP for treatment.
• two (2) each influent settling/equalization(EQ)basins for raw water from different sources
• dual(2)treatment trains
• reverse osmosis(RO) for deep-well source water
• geensand/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
RENEWAL SUMMARY
This renewal contains the following changes:
• 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. (1.).
• Updated eDMR parameter codes on the effluent table in Section A. (1.).
• Updated footnotes in the effluent table in Section A. (1.).
• Updated Whole Effluent Toxicity testing language in Part I. A. (2).
• Updated eDMR language for electronic data submission in Part 1. A. (3).
• Updated the map.
COMPLIANCE HISTORY
Southern Outer Banks Water System WTP has had no enforcements on record. The facility has been issued
one proceed to NOD for a Total Suspended Solids frequency violation in Sept 2020.
Most recent inspection(April 2021) showed the facility to be compliant.
WHOLE EFFLUENT TOXICITY(WET)TESTING
In accordance with current strategies designating this facility as a Membrane/Ion-Exchange/Greenland
water treatment plant,WET testing is required in this permit as saltwater Chronic [TGP3E] Pass/Fail
Quarterly monitoring with Mysidopsis bahia at an effluent concentration of 0.67%. The previous 12
quarterly whole effluent toxicity tests have passed.
Date Parameter Sample UoM Value Location
TGP3E-Pass/Fail Static Renewal 7Day
10/7/2019 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
TGP3E-Pass/Fail Static Renewal 7Day
4/6/2020 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
TGP3E-Pass/Fail Static Renewal 7Day
7/13/2020 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
TGP3E-Pass/Fail Static Renewal 7Day
10/5/2020 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
Fact Sheet for Permit Renewal
March 2024-NPDES Permit NCO087670-Page 2

1/4/2021 TGP3E-Pass/Fail Static Renewal May Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
4/6/2021 TGP3E-Pass/Fail Static Renewal May Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
TGP3E-Pass/Fail Static Renewal May7/13/2021 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
TGP3E-Pass/Fail Static Renewal May10/4/2021 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
TGP3E-Pass/Fail Static Renewal May1/3/2022 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
TGP3E-Pass/Fail Static Renewal May4/4/2022 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
TGP3E-Pass/Fail Static Renewal May7/11/2022 Chronic Americam sis M sid. Bahia Composite pass/fail 1 Effluent
10/5/2022 TGP3E-Pass/Fail Static Renewal May Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
1/4/2023 TGP3E-Pass/Fail Static Renewal May Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
4/5/2023 TGP3E-Pass/Fail Static Renewal May Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
7/12/2023 TGP3E-Pass/Fail Static Renewal 7Day Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
10/4/2023 TGP3E-Pass/Fail Static Renewal May Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
1/3/2024 TGP3E-Pass/Fail Static Renewal May Composite pass/fail 1 Effluent
Chronic Americam sis M sid. Bahia
REASONABLE POTENTIAL ANALYSIS
There are currently no parameters of concern generating data appropriate for an RPA. A maximum
monthly average flow of 1.02 MGD was calculated using data from the past three years.
Fact Sheet for Permit Renewal
March 2024-NPDES Permit NC0087670-Page 3

Permit Enforcement History by Permit
Permit: Facility: Owner:
Region: County:
Penalty Remission Enforcement EMC Collection Has
Assessment Penalty Enforcement Request Conference Hearing Memo Sent Payment Case
Case Approved Amount Costs Damages Received Held Held To AGO Total Paid Balance Due Plan Closed
Total Cases:
Total Penalties: Total Penalties after

MONITORING REPORT(MR)VIOLATIONS for: Report Date: 04/02/24 Page 1 of 1
Permit: NCO087670 MRS Betweel 4 - 2018 and 4 - 2024 Region: % Violation Category:% Program Category:NPDES WW
Facility Name:% Param Nam(% County: % Subbasin:% Violation Action:
Major Minor: % or
PERMIT: NCO087670 FACILITY: Currituck County-Southern Outer Banks Water COUNTY: Currituck REGION: Washington
System WTP
Monitoring Violation
MONITORING VIOLATION UNIT OF CALCULATED %
REPORT OUTFALL LOCATION PARAMETER DATE FREQUENCY MEASURE LIMIT VALUE Over VIOLATION TYPE VIOLATION ACTION
05-2023 001 Effluent Nitrogen,Ammonia Total(as 05/31/23 Monthly mg/I Frequency Violation No Action, Facility
N)-Concentration Reporting Error
09-2020 001 Effluent Solids,Total Suspended- 09/05/20 Weekly mg/I Frequency Violation Proceed to NOD
Concentration

Whole Effluent Toxicity Testing and Self Monitoring Summary
South Durham WRF NCO047597/001 County: Durham Region: RRO Basin: CPF05 Jan Apr Jul Oct SOC JOC:
Ceri7dPF Begin: 11/1/2011 chr lim:90% NonComp: Single 70,10: 0.15 PF: 20.0 IWC: 99.5 Freq: Q
J F M A M J J A S O N D
2020 Pass - - Pass - - Pass - - Pass - -
2021 Pass - - Pass - - Pass - - Pass - -
2022 Pass - - Pass - - Pass - - Pass - -
2023 Pass - - Pass - - Pass - - Pass - -
2024 Pass - - - - - - - - - - -
South Fork-(formerly Delta Apparel) NC0006190/001 County: Catawba Region: MRO Basin: CTB35 Mar Jun Sep Dec SOC JOC:
Cer7dChV Begin: 2/1/2019 chr lim:12%**A(4) NonComp: Single 70,10: 12 PF: 1.1 IWC: 11 Freq: Q
J F M A M J J A S O N D
2020 - - 16.97 - - Pass - - >48 - - 4.2
2021 4.2 <3 <3 8.5 >48 33.9 - - >48 - - 4.2 INC)
2022 <3 INC) 4.2 INC) 8.5 INC) 17 17 17 33.9 - 69.3 - - 33.9
2023 - - 33.9 - - 33.9 - - 69.3 - - 17
South Harnett County Regional WWTP NCO088366/001 County: Harnett Region: FRO Basin: CPF14 Jan Apr Jul Oct SOC JOC:
Ceri7dPF Begin: 2/1/2018 Chr Lim:34%@ 15 M NonComp: 70.10: 45.46 PF: 5.0 IWC: 15 Freq: Q
J F M A M J J A S O N D
2020 >100(P)Pass - - Pass - - Pass - - Pass - -
2021 INVALID Pass - Pass - - Pass - - Pass - -
2022 Pass - - Pass - - Pass - - Pass - -
2023 >100 Pass - - Pass - - Pass - - Pass - -
2024 Pass - - - - - - - - - - -
South Mills Water Association WTP NC0007978 County: Camden Region: WARD Basin: Pas50 Jan Apr Jul Oct SOC JOC:
Ceri7dPF Begin: 8/1/2014 Chr monit:90% NonComp: 70.10: N/A PF: 0.045 IWC: N/A Freq: Q
J F M A M I I A S O N D
2020 Fail - - Fail - - Fail - - Fail - -
2021 Fail - - Pass - - Fail - - Fail - -
2022 Fail - - Fail - - Pass - - Pass - -
2023 Pass - - Fail - - H NR H H H H -
Southern Outer Banks(RO)WTP NCO087670/001 County: Currituck Region: WARO Basin: PAS54 Jan Apr Jul Oct SOC JOC:
Mysd24PF Begin: 4/1/2018 Chr Monit 24hr PF:0. NonComp: 7Q10: Tidal PF: 0.6 IWC: NA Freq: Q
J F M A M J J A S O N D
2020 - Pass - Pass - - Pass - - Pass - -
2021 Pass - - Pass - - Pass - - Pass - -
2022 Pass - - Pass - - Pass - - >0.67 - -
2023 Pass - - Pass - - Pass - - Pass - -
2024 Pass - - - - - - - - - - -
Southern Piedmont Wood Co NCO087572/002 County: Chatham Region: RRO Basin: CPF10 Feb May Aug Nov SOC JOC:
Ceri48PF Begin: 12/1/2011 Ac Monit: 0.22% NonComp: 7Q10: 22 PF: 0.42 IWC: Freq: W*
J F M A M J J A S O N D
2020 - H - - - - - - - - - -
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