NC0063029_Fact Sheet_20240624

Fact Sheet
NPDES Permit No. NCOO63O29
Permit Writer/Email Contact Sergei Chernikov, Ph.D., [e-mail]
Date: May 24, 2023
Division/Branch: NC Division of Water Resources/NPDES Complex Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
® Renewal
❑ Renewal with Expansion
❑ New Discharge
❑ Modification (Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2°d species WET
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
Basic Facilitv Information
Facility Information
Applicant/Facility Name:
Commanding General/ Camp Lejeune Advanced WWTP
Applicant Address:
12 Post lane, Rm 244, Camp Lejeune, NC 28547
Facility Address:
Building FC440, Gonzalez Boulevard, Marine Camp Base, Camp
Lejeune/PFAS unit is housed in Building AS3525
Permitted Flow:
15.0 MGD
Facility Type/Waste:
Major Facility
Facility Class:
Class IV
Treatment Units:
Parshall Flume, Bar Screen, Grit Removal, Primary Clarifiers, Nutrient
Removal System, Secondary Clarifiers, Sand Filters, Pump Stations, Post
Aeration Basin, Effluent Diffuser, Ultraviolet (UV) Disinfection system,
Rotary Drum Sludge Thickeners, Aerobic Digester, Sludge Holding
Tank, and Sludge Drying Beds.
PFAS treatment: Iron Pretreatment, Granular Activated Carbon (GAC),
and Ion Exchange.
Pretreatment Program (Y/N)
No
County:
Onslow
Region
Wilmington
Page 1 of 14

Briefly describe the proposed permitting action and facility background: United States Marine Corps Base,
Camp Lejeune (MCB CAMLEJ), herein called MCP CAMLEJ or Permittee, applied for an NPDES permit
renewal for Camp Lejeune Advanced Wastewater Treatment Plant (WWTP). Camp Lejeune Advanced
WWTP is a state-of-the-art facility that began operation in 1998 and consolidated seven discharges. The
facility serves Marine Corps Base Camp Lejeune and Marine Corps Air Station New River with a total
population of 148,000.
MCP CAMLEJ receives waste streams from Onslow Water and Sewer Authority (ONWASA), Naval
Medical Center (NMC), Oil Water Separators (OWS), Municipal Solid Waste Landfill Facility (MSWLF)
leachate, Solid Waste Compost Facility (SWCF) runoff, four Water Treatment plants (WTPs) filter
backwash and seven remedial treatment plants. The remediation systems include: Installation Restoration
(IR) Site 78 North, IR Site 78 South, AS-4141, HPFF South East Compound, New River PPV, TC-341
Pipeline and Rapid Refueler (attached the description of each site). RCRA Sites AS-4141 and Rapid
Ref iler have been shut down since the discovery of Per- and Polyfluoroalkyl Substances (PFAS) in their
effluent. No other sources of PFAS have been identified flowing to the facility.
According to 2007 White Oak River Basin Plan, Nutrient enrichment has been a significant problem in the
estuarine portions of the New River, and periodic elevated fecal coliform bacteria levels also appear to be
a recurring problem in this subbasin (03-05-02). High nutrient levels were being discharged by the City of
Jacksonville as well as Camp Lejeune. In 1998, Jacksonville removed its discharge from the upper New
River estuary and Camp Lejeune consolidated its seven discharges into one tertiary treatment facility. These
discharges were considered a major source of nutrients into the upper estuarine portions of the New River.
As a result, a reduction of nitrogen and phosphorous, 57 and 71 percent respectively, has occurred.
In 2024 the facility will install two (2) mobile PFAS treatment systems. The systems will be moved around
the site to treat aqueous PFAS impacted construction or operational wastes, including groundwater and
rinsate from cleaning contaminated tanks/systems.
The wastewater will be pre-treated for iron, as necessary, followed by GAC, and Ion Exchange treatment
for PFAS. The wastewater will be run through the system until PFAS are below EPA health advisory levels
(PFOA + PFOS < 70.0 ng/L MA and WA). The treatment system will operate in batches and will utilize
frac tanks to allow effluent sampling prior to discharge. The proposed flow rate is 10 gpm (0.0144) for each
unit. The effluent from the PFAS treatment system shall be discharged via Internal Outfall 002 and Internal
Outfall 003 to Outfall 001.
The PFOA + PFOS limits at the internal outfalls will translate into values that are below proposed state
standards for 8 PFAS compounds: PFOA, PFOS, PFBA, PFBS, GenX, PFHxA, PFNA, PFHs. The first
reported data set for both internal outfalls indicates that the vast majority of reported values are below 10
ng/L. Since there are no drinking water intakes below this treatment plant, the effluent PFAS concentrations
are sufficient to be protective of the receiving stream.
Page 2 of 14

2. Receiving Waterbodv Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 - New River, Internal Outfall 002 and 003 (PFAS
treatment system).
Stream Segment:
19-(15.5)
Stream Classification:
SC; NSW
Drainage Area (mi2):
12a
Summer 7Q10 (cfs)
Tidal
Winter 7Q10 (cfs):
Tidal
30Q2 (cfs):
Tidal
Average Flow (cfs):
Tidal
IWC (% effluent):
5% (modeled)63029
303(d) listed/parameter:
No
Subject to TMDL/parameter:
Yes- Statewide Mercury TMDL implementation.
Subbasin/HUC:
03-05-02; 03020302
USGS Topo Quad:
Camp Lejeune 129 NE
a: Based on Stream-stats (streamstats.usgs.gov)
3. Effluent Data Summary
Effluent data for Outfall 001 is summarized below for the period of January 2019 through November
2023.
Table 3. Effluent Data Summary Outfall 001.
Permit
Parameter
Units
Average
Max
Min
Limit
Flow
MGD
4 4 �,
17.0
1.00
MA 15.0
BOD
DM 7.5
mg/L
2.41
11.7
< 2.00
MA 5.0
summer
BOD
DM 15.0
mg/L
2.36
12.0
< 2.00
MA 10.0
winter
Page 3 of 14

TSS
mg/L
2.59
23.4
< 2•5
DM 45.0MA
30.0
NH3N summer
mg/L
1 _�� i
3.1
< 1.00
DM 10.0
MA 2.0
NH3N winter
mg/L
1 c
11.4
< 1.00
DM 20.0
MA 4.0
DO
mg/L
DA > 6.0
pH
SU
7.8
6.8 < pH <
8.5
Enterococci
#/100 mL
4 51
875.25
< 1.00
(geometric)
WA 276.0
MA 35.0
Total Nitrogen
mg/L
1.04
11.4
< 0.1
Total Phosphorus summer
mg/L
0.28
0.9
0.1
MA 0.5
Total Phosphorus winter
mg/L
0.28
2.9
0.07
MA 1.0
Oil and Grease
mg/L
5.1
9.00
< 5.00
DM 60.0
MA 30.0
MA -Monthly Average, WA -Weekly Average, DM -Daily Maximum, DA=Daily Average
Facility uses UV disinfection system
4. Instream Data Summary
Instream monitoring may be required in certain situations, for example: 1) to verify model predictions when
model results for instream DO are within I mg/l of instream standard at full permitted flow; 2) to verify
model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other instream
concerns. Instream monitoring may be conducted by the Permittee, and there are also Monitoring
Coalitions established in several basins that conduct instream sampling for the Permittee (in which case
instream monitoring is waived in the permit as long as coalition membership is maintained).
If applicable, summarize any instream data and what instream monitoring will be proposed for this permit
action: The current permit requires twice -per -month instream sampling during summer season (April -
October) for physical (DO, Salinity, Temperature, Conductivity, pH, and Secchi Depth) and
chemical/biological parameters (Total Phosphorus, NH3-N, TKN, Nitrate and Nitrite, Chlorophyll -a and
Fecal Coliform). These parameters are collected at nine instream monitoring stations: three stations are
located upstream of the diffuser at Farnell Bay Transect (stations #4 - #6), three stations are located near
the diffuser at Spring Point Transect (stations #7 - #9) and three stations are downstream of the diffuser at
Grey Point Transect (stations #10 - #12).
A review of instream data from January 2019 through November 2023 the DO sampling results were
generally above 5 mg/L (373 samples out of 391). The low DO values occurred in July, August, and
September.
pH values were mainly within the normal range of 6.8-8.5 for SC water (312 values out of 392).
Page 4 of 14

No changes are proposed for instream monitoring.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (YIN): NO
Name of Monitoring Coalition: NA
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past S years): The facility had 3 limit
violation for BOD in 2021 and 1 limit violation for TRC in 2020.
Summarize the compliance record with aquatic toxicity test limits and any second species test results (past
5 years): The facility passed 20 of 20 quarterly chronic toxicity tests.
Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in 2023 determined that the facility was compliant with the permit.
6. Water Quality -Based Effluent Limitations (WQBELs)
Dilution and Mixin Zones
ones
In accordance with 15A NCAC 2B.0206, the following streamflows are used for dilution considerations
for development of WQBELs: 1Q10 streamflow (acute Aquatic Life); 7Q10 streamflow (chronic Aquatic
Life; non -carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH).
If applicable, describe any other dilution factors considered (e.g., based on CORMLX model results):
CORMIX model was performed in 1995, resulting in 20:1 dilution (5% IWC) at the outfall.
Ifapplicable, describe any mixingzones established in accordance with 1 SA NCAC 2B.0204(b): No mixing
zone was established.
Oxygen -Consuming Waste Limitations
Limitations for oxygen -consuming waste (e.g., BOD) are generally based on water quality modeling to
ensure protection of the instream dissolved oxygen (DO) water quality standard. Secondary TBEL limits
(e.g., BOD= 30 mg/1 for Municipals) may be appropriate if deemed more stringent based on dilution and
model results.
Ifpermit limits are more stringent than TBELs, describe how limits were developed: Limitations for BOD
are based on 1992 Waste Load Allocation (WLA) using Georgia Estuary Model (GAEST) for instream DO
protection. No changes are proposed from the previous permit limits.
Ammonia and Total Residual Chlorine Limitations
Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of
1.0 mg/1(summer) and 1.8 mg/1(winter). Acute ammonia limits are derived from chronic criteria, utilizing
a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -Municipals.
Page 5 of 14

Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection
of aquatic life (17 ug/1) and capped at 28 ug/1 (acute impacts). Due to analytical issues, all TRC values
reported below 50 ug/1 are considered compliant with their permit limit.
Describe any proposed changes to ammonia andlor TRC limits for this permit renewal: The TRC limit set
at 13 µg/L per the EPA NRWQC for saltwater aquatic life protection.
NH3-N limits are based on 1992 Waste Load Allocation (WLA) using Georgia Estuary Model (GAEST).
No changes for TRC and NH3-N are proposed from the previous permit limits. Table 5 summarizes the
NH3-N Limits.
Table 5. NH3-N Limit
Season
Monthly Avg. m
Daily Max. m
Summer
2.0
10.0
Winter
4.0
20.0
Reasonable Potential Analysis (RPA) for Toxicants
If applicable, conduct RPA analysis and complete information below.
The need for toxicant limits is based upon a demonstration of reasonable potential to exceed water quality
standards, a statistical evaluation that is conducted during every permit renewal utilizing the most recent
effluent data for each outfall. The RPA is conducted in accordance with 40 CFR 122.44 (d) (i). The NC
RPA procedure utilizes the following: 1) 95% Confidence Level/95% Probability; 2) assumption of zero
background; 3) use of %2 detection limit for "less than" values; and 4) streamflows used for dilution
consideration based on 15A NCAC 2B.0206. Effective April 6, 2016, NC began implementation of
dissolved metals criteria in the RPA process in accordance with guidance titled NPDES Implementation of
Instream Dissolved Metals Standards, dated June 10, 2016.
A reasonable potential analysis was conducted on effluent toxicant data collected during the last 5
years. Pollutants of concern included toxicants with positive detections and associated water quality
standards/criteria. Based on this analysis, the following permitting actions are proposed for this permit:
• Effluent Limit with Monitoring. The following parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable water
quality standards/criteria: None
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria, but
the maximum predicted concentration was >50% of the allowable concentration: None
• No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demonstrate reasonable potential to exceed applicable water quality standards/criteria
and the maximum predicted concentration was <50% of the allowable concentration: As, Be, Cd,
Total Phenols, Total Cr, Cu, CN, Pb, Hg, Ni, Se, Ag, Zn, and Tl.
Toxicity Testing Limitations
Permit limits and monitoring requirements for Whole Effluent Toxicity (WET) have been established in
accordance with Division guidance (per WET Memo, 8/2/1999). Per WET guidance, all NPDES permits
issued to Major facilities or any facility discharging "complex" wastewater (contains anything other than
Page 6 of 14

domestic waste) will contain appropriate WET limits and monitoring requirements, with several exceptions.
The State has received prior EPA approval to use an Alternative WET Test Procedure in NPDES permits,
using single concentration screening tests, with multiple dilution follow-up upon a test failure.
Describe proposed toxicity test requirement: This is a major Federally Owned Treatment Work (FOTW),
and a chronic WET limit at 5% effluent will continue on a quarterly frequency.
Mercury Statewide TMDL Evaluation
There is a statewide TMDL for mercury approved by EPA in 2012. The TMDL target was to comply with
EPA's mercury fish tissue criteria (0.3 mg/kg) for human health protection. The TMDL established a
wasteload allocation for point sources of 37 kg/year (81 lb/year) and is applicable to municipals and
industrial facilities with known mercury discharges. Given the small contribution of mercury from point
sources (^-2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source
control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/1) will receive
an MMP requirement. Industrials are evaluated on a case -by -case basis, depending if mercury is a pollutant
of concern. Effluent limits may also be added if annual average effluent concentrations exceed the WQBEL
value (based on the NC WQS of 12 ng/1) and/or if any individual value exceeds a TBEL value of 47 ng/1
Describe proposed permit actions based on mercury evaluation: The facility provided 3 annual samples:
1.55 ng/L, 1.24 ng/L, and 1.27 ng/L. Since no annual average mercury concentration exceeded the WQBEL
of 240.6 ng/L, and no individual mercury sample exceeded the TBEL of 47.0 ng/L, no mercury limit is
required.
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TMDLsNutrient Management Strategies and their implementation within
this permit: "The New River was classified as a Nutrient Sensitive Water due to excessive growth of
microscopic and/or macroscopic vegetation. Based on results of water quality sampling from June 1986 to
September 1989, the NSW regulations were amended to include the New River above Grey Point. Per the
NSW regulations, 15 A NCAC 2B .0214, and the implementation plan for the New River basin, a Total
Phosphorus limit of 2 mg/L is required of all existing discharges with design flow rates of 0.05 MGD or
greater. All new and expanded discharges above Grey Point are required to meet a Total Phosphorus limit
of 0.5 mg/L regardless of design capacity. More stringent controls on nutrient inputs such as a Total
Nitrogen effluent limit may be required in the future on a case -by -case basis" (Summary Report: Camp
Lejeune: Wasteload Allocation for the expansion of Hadnot Point WWTP to 15 MGD, December 1992).
Phosphorus: The Permittee's 0.5 mg/L Total Phosphorus limit for the summer season (April through
October) and 1.0 mg/L Total Phosphorus limit for winter season (November through March) are in
accordance with 1992 NSW strategy for expanding discharges in the New River.
Nitrogen: The Permittee's 251,356 pounds/year Total Annual Nitrogen (TAN) Load, calculated based on
total nitrogen concentration of 5.5 mg/L at 15 MGD, is in accordance with G.S 143-215.1c1 for NSW and
HB515.
Other WOBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: NA
Page 7 of 14

If applicable, describe any special actions (HQW or ORW) this receiving stream and classification shall
comply with in order to protect the designated waterbody: Due to proximity of SA, HQW that are open to
shellfish harvesting and the concerns of Division of Marine Fisheries (DMF), instream monitoring of Fecal
Coliform was added to the permit issued in 2013.
If applicable, describe any compliance schedules proposed for this permit renewal in accordance with 15A
NCAC 2H.0107( c)(2)(B), 40CFR 122.47, and EPA May 2007 Memo: NA
If applicable, describe any water quality standards variances proposed in accordance with NCGS 143-
215.3(e) and 15A NCAC 2B.0226 for this permit renewal: NA
7. Technology -Based Effluent Limitations (TBELs)
Industrial/Commercial
Describe what this facility produces: US Marine Corps Base
List the federal effluent limitations guideline (ELG) for this facility: NA
If the ELG is based on production or flow, document how the average production/flow value was
calculated: NA
For ELG limits, document the calculations used to develop TBEL limits: NA
8. Antidegradation Review (New/Expanding Discharge):
The objective of an antidegradation review is to ensure that a new or increased pollutant loading will not
degrade water quality. Permitting actions for new or expanding discharges require an antidegradation
review in accordance with 15A NCAC 2B.0201. Each applicant for a new/expanding NPDES permit must
document an effort to consider non -discharge alternatives per 15A NCAC 2H.0105(c)(2). In all cases,
existing instream water uses and the level of water quality necessary to protect the existing use is maintained
and protected.
If applicable, describe the results of the antidegradation review, including the Engineering Alternatives
Analysis (EAA) and any water quality modeling results: NA
9. Antibacksliding Review:
Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations
may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit (YESINO): No
If YES, confirm that antibacksliding provisions are not violated: NA
Page 8 of 14

10. Monitoring Requirements
Monitoring frequencies for NPDES permitting are established in accordance with the following regulations
and guidance: 1) State Regulation for Surface Water Monitoring, 15A NCAC 2B.0500; 2) NPDES
Guidance, Monitoring Frequency for Toxic Substances (7/15/2010 Memo); 3) NPDES Guidance, Reduced
Monitoring Frequencies for Facilities with Superior Compliance (10/22/2012 Memo); 4) Best Professional
Judgement (BPJ). Per US EPA (Interim Guidance, 1996), monitoring requirements are not considered
effluent limitations under Section 402(o) of the Clean Water Act, and therefore anti -backsliding
prohibitions would not be triggered by reductions in monitoring frequencies.
For instream monitoring, refer to Section 4.
11. Electronic Reporting Requirements
The US EPA NPDES Electronic Reporting Rule was finalized on December 21, 2015. Effective December
21, 2016, NPDES regulated facilities are required to submit Discharge Monitoring Reports (DMRs)
electronically. Effective December 21, 2020, NPDES regulated facilities will be required to submit
additional NPDES reports electronically. This permit contains the requirements for electronic reporting,
consistent with Federal requirements.
12.Summary of Proposed Permitting Actions:
A. Table. Current Permit Conditions and Proposed Changes 15.0 MGD
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
I -low
MA 15.0 MGD
No change
15A NCAC 2B .0505
Total Monthl
Monitor and Report
No change
Aid in calculating Total Nitrogen
Flow
loading.
BODs
Summer:
No change
WQBEL. Based on 1992 Waste Load
MA 5.0 mg/L
Allocation (WLA) using Georgia
DM 7.5 mg/L
Estuary Model (GAEST) for
Winter:
instream DO protection.
MA 10.0 mg/L
DM 15.0 mg/L
Monitor Dail
TSS
MA 30 mg/L
No change
TBEL. Secondary treatment
DM 45 mg/L
standards/40 CFR 133 / 15A NCAC
2B .0406
Monitor Daily
NH3-N
Summer:
No change
WQBEL. Based on 1992 Waste Load
MA 2.0 mg/L
Allocation (WLA) using Georgia
DM 10.0 mg/L
Estuary Model (GAEST)
Winter:
Page 9 of 14

MA 4.0 mg/L
MFR criteria were met
DM 20.0 mg/L
Monitor Dail
DO
> 6 mg/L
No change
WQBEL. State WQ standard, 15A
NCAC 2B .0200
pH
6.8 - 8.5 SU
No change
WQBEL. State WQ standard, 15A
NCAC 2B .0220
Total Residual
DM 13.0 µg/L
No change
WQBEL. EPA Nationally
Chlorine
Recommended Water Quality
Criteria for Salt Water, 2006.
Temperature
Monitor Daily
No change
WQBEL. State WQ standard, 15A
NCAC 2B .0200 and .0500
Enterococci
MA 35 /100mL
No change
WQBEL. State WQ standard, 15A
WA 276 /100mL
NCAC 2B .0220
Monitor Dail
Total Nitrogen
Monitor Weekly
No change
For Total Nitrogen Load Calculation
(mom-)
and to comply with 15A NCAC 2B
Total Nitrogen
Monitor monthly
No change
WQBEL. in accordance with G.S
251,356 (lbs/year)
143-215.1cl for NSW
Total Phosphorus
Summer:
No change
in accordance with 1992 NSW
MA 0.5 mg/L
strategy for expanding discharges in
Winter:
the New River
MA 1.0 mg/L
Oil and Grease
MA 30.0 mg/L
No change
Best Professional Judgment (BPJ)
DM 60.0 m
Toxicity Test
Chronic limit, 5%
No change
WQBEL. No toxics in toxic
effluent
amounts. 15A NCAC 2B.0200 and
15A NCAC 2B.0500
Effluent Pollutant
3 times per permit cycle
No change
40 CFR 122
Scan
Electronic
Electronic Reporting
No change
In accordance with EPA Electronic
Reporting
Special Condition
Reporting Rule 2015.
PFAS
Monitoring for 40
No change
EPA's PFAS Guidance
Applicable PFAS
compounds
MUD - Million gallons per day, MA - Monthly Average, WA - Weekly Average, DM - Daily Max
Page 10 of 14

B. Table. Current Permit Conditions and Proposed Changes (Internal Outfall 002 and Internal Outfall
003).
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
PFOA + PFOS
PFOA+PFOS<70.0 ng/I .
(MA and WA)
No change
EPA health advisory
MGD — Million gallons per day, MA - Monthly Average, WA — Weekly Average, DM — Daily Max
13. Public Notice Schedule:
Permit to Public Notice: XX/XX/2024
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice. Any request for a public hearing shall be submitted to the Director
within the 30 days comment period indicating the interest of the party filing such request and the reasons
why a hearing is warranted.
14. NPDES Division Contact:
If you have questions regarding any of the above information or on the attached permit, please contact
Sergei Chernikov at (919) 707 - 3606 or via email at [e-mail].
15. Fact Sheet Addendum (if applicable):
Were there any changes made since the Draft Permit was public noticed (Yes/No):
If Yes, list changes and their basis below:
16. Fact Sheet Attachments (if applicable):
• RPA Spreadsheet summary/Saltwater
• Wet Testing summary results
Page 11 of 14

NPDES Implementation of Instream Dissolved Metals Standards — Saltwater Standards
The NC 2007-2015 Water Quality Standard (WQS) Triennial Review was approved by the NC
Environmental Management Commission (EMC) on November 13, 2014. The US EPA subsequently
approved the WQS revisions on April 6, 2016, with some exceptions. Therefore, metals limits in draft
permits out to public notice after April 6, 2016 must be calculated to protect the new standards - as
approved.
Table 1. NC Dissolved Metals Water Q ality Standards/A uatic Life Protection
Parameter
Acute FW, µg/1
(Dissolved)(Dissolved)
Chronic FW, µg/1
Acute SW, µg/1
(Dissolved)
Chronic SW, µg/l
(Dissolved)
Arsenic
340
150
69
36
eryllium
5
5
---
---
admium
alculation
alculation
0
8.8
hromium III
alculation
alculation
---
---
hromium VI
16
1
1100
50
opper
alculation
alculation
106
.8
3.1
ad
alculation
alculation
10
8.1
ickel
alculation
alculation
74
8.2
Silver
alculation
1.9
0.1
inc
ralculation
ralculation
90
81
Table 1 Notes:
1. FW= Freshwater, SW= Saltwater
2. Calculation = Hardness dependent standard
3. Only the aquatic life standards listed above are expressed in dissolved form. Aquatic life
standards for Mercury and selenium are still expressed as Total Recoverable Metals due to
bioaccumulative concerns (as are all human health standards for all metals). It is still
necessary to evaluate total recoverable aquatic life and human health standards listed in 15A
NCAC 213.0200 (e.g., arsenic at 10 µg/l for human health protection; cyanide at 5 µg/L and
fluoride at 1.8 mg/L for aquatic life protection).
General Information on the Reasonable Potential Analysis (RPA)
The RPA process itself did not change as the result of the new metals standards. However, application of
the dissolved metal standards requires additional consideration in order to establish the numeric standard
for each metal of concern of each individual discharge. Note that none of the saltwater standards are
hardness -dependent.
Metals limits must be expressed as `total recoverable' metals in accordance with 40 CFR 122.45(c). The
discharge -specific standards must be converted to the equivalent total values for use in the RPA
calculations. We will generally rely on conversion factors determined by EPA (more on that below), but it
is also possible to consider case -specific translators developed in accordance with established
methodology.
RPA Permitting Guidance — Discharges to Saltwater (Tidal waters)
The RPA is designed to predict the maximum likely effluent concentrations for each metal of concern,
based on recent effluent data, and calculate the allowable effluent concentrations, based on applicable
Page 12 of 14

standards and the stream dilution. For discharges to saltwater, no allowance for dilution is given unless a
dilution study, such as a CORMIX model, is performed.
If the maximum predicted value is greater than the maximum allowed value (chronic or acute), the
discharge has reasonable potential to exceed the standard, which warrants a permit limit in most cases. If
monitoring for a particular pollutant indicates that the pollutant is not present (i.e. consistently below
detection level), then the Division may remove the monitoring requirement in the reissued permit.
1. To perform a RPA using the saltwater dissolved metal standards, the Permit Writer
compiles the following information:
• Permitted flow
• Receiving stream classification
• Instream Wastewater Concentration, if a dilution model has been performed
2. The RPA spreadsheet converts the dissolved numeric standard (SW standards listed in
Table 1.) for each metal of concern to a total recoverable metal, using the EPA conversion
factors published in the June, 1996 EPA Translator Guidance Document. This method
presumes that the metal is dissolved to the same extent as it was during EPA's criteria
development for metals.
Conversion Factors for Dissolved Metals
SaltwaterCMC
Saltwater CCC
Metal
(Acute)
(chronic)
Arsenic
1.000
1.000
Cadmium
0.994
0.994
Chromium VI
0.993
0.993
Copper
0.83
0.83
Lead
0.951
0.951
Mercury
0.85
0.85
Nickel
0.990
0.990
Selenium
0.998
0.998
Silver
0.85
—
Zinc
0.946
0.946
From: US EPA website, National Recommended Water Quality
Criteria - Aquatic life Criteria Table
httos: //www.e oa.zov/wac/nation al-recommended-wate r-
ouality-criteria-aouatic-life-criteria-table#
3. The dissolved numeric standard for each metal of concern is divided by the EPA
conversion factor (or site -specific translator) to obtain a Total Recoverable Metal at ambient
conditions.
4. If a dilution study was performed on the receiving stream and an Instream Wastewater
Concentration (IWC) determined the RPA spreadsheet uses a mass balance equation to
determine the total allowable concentration (permit limits) for each pollutant using the
following equation:
Ca = (s7010 + Owl (Cwgs) — WO10) (Cb)
QW
Where: Ca = allowable effluent concentration (µg/L or mg/L)
Cwqs = NC Water Quality Standard or federal criteria (µg/L or mg/L)
Page 13 of 14

Cb = background concentration: assume zero for all toxicants except NH3* (µg/L or mg/L)
Qw = permitted effluent flow (cfs, match 7Q10 units)
s7Q 10 = summer, critical low flow (cfs)
* Discussions are on -going with EPA on how best to address background concentrations
Assuming no background concentration, this equation can be reduced to:
Ca = (s7O10 + Ow) (Cwgs) or Ca = Cwas
Qw IWC
Where: IWC Ow or 1
Qw + s7Q 10 D
and D = modelled dilution factor (unitless)
If no dilution study has been performed Ca, the allowable effluent concentration, is equal to the
Total Recoverable Metal determined at ambient conditions (ie. the dissolved numeric standard
divided by the EPA conversion factor (or site -specific translator) for the metal of concern). See
item # 3 above.
5. The permit writer enters the most recent 2-3 years of effluent data for each pollutant of
concern. Data entered must have been taken within four and one-half years prior to the date
of the permit application (40 CFR 122.21). The RPA spreadsheet estimates the 95th
percentile upper concentration of each pollutant. The Predicted Max concentrations are
compared to the Total allowable concentrations to determine if a permit limit is necessary. If
the predicted max exceeds the acute or chronic Total allowable concentrations, the discharge
is considered to show reasonable potential to violate the water quality standard, and a permit
limit (Total allowable concentration) is included in the permit in accordance with the U.S.
EPA Technical Support Document for Water Quality -Based Toxics Control published in
1991.
6. When appropriate, permit writers develop facility specific compliance schedules in
accordance with the EPA Headquarters Memo dated May 10, 2007 from James Hanlon to
Alexis Strauss on 40 CFR 122.47 Compliance Schedule Requirements.
7. The Total Chromium NC WQS was removed and replaced with a hexavalent chromium
standard. As a cost savings measure, total chromium data results may be used as a
conservative surrogate in cases where there are no analytical results based on chromium VI.
In these cases, the projected maximum concentration (95th %) for total chromium will be
compared against the water quality standard chromium VI.
Page 14 of 14