NC0057533_Fact Sheet_20200206

FACT SHEET FOR PERMIT RENEWALS
Basic Information for Permit Renewals
Permit Writer / Date
Brianna Young 2/5/2020
Permit Number
NCO057533
Facility Name / Facility Class
Northwest WTP / PC-1
Basin Name / Sub -basin number
Outfall 001: Cape Fear / 03-06-17
Outfall 002: Cape Fear / 03-06-17
Receiving Stream / HUC
Outfall 001: Hood Creek / 0303000504
Outfall 002: Cape Fear River / 0303000504
Stream Classification / Stream Segment
Outfall 001: C; Sw / Index: 18-66
Outfall 002: C; Sw, PNA / Index: 18- 63
Does permit need Daily Maximum NH3
N/A
limits?
Does permit need TRC limits/language?
Outfall 001: Already present
Outfall 002: Added
Does permit have toxicity testing? IWC (%) if
Outfall 001: Yes; IWC = 90%
so
Outfall 002: Yes; IWC = 33.3% (based on
dilution model
Does permit have Special Conditions?
Yes see Section 11 below
Does permit have instream monitoring?
Outfall 001: Yes - hardness
Outfall 002: Yes — DO, salinity, conductivity,
H, hardness
Is the stream impaired (on 303(d) list)?
Outfall 001: No
Outfall 002: No
Any obvious compliance concerns?
Yes see Section 4 below
Any permit mods since last permit?
Yes; proposed expansion for entire facility
and new outfall for new RO treatment units
New expiration date
3/31/2023
Comments on Draft Permit?
Yes see Section 14
Section 1. Existing Facility and Discharge (Outfall 001):
The Northwest (Hood Creek) WTP currently utilizes conventional treatment technology,
with a potable design of 24 MGD. Outfall 001 has a compliance schedule for total copper
and total fluoride, and permit reopener conditions are present for WET testing and TMDL
implementation.
Potable water and wastewater treatment currently consists of:
• Influent disinfection [chlorination]
• Two (2) 12 MGD up -flow clarifiers [disinfected raw water]
• Two (2) banks of four (4) filters each [sand/anthracite/gravel filter]
• One (1) 4 MGD clear well
• One (1) 2 MGD surge lagoon
• One (1) 0.180 MGD sludge thickener
• Dechlorination
• Chemical usage consists of.
Page 1 of 54

o Chlorine dioxide
0 50% sodium hydroxide
o Polyaluminum chloride
o Sodium silica fluoride
o Bleach -type solutions
o Cationic polymer solutions
o Calcium thiophosphate
o Powered activated carbon
o Orthophosphate
Section 2. Proposed Facility and Discharge (Outfalls 001 and 002):
The permittee has requested a modification of the permit for an existing conventional
WTP located in Leland in Brunswick County that wishes to expand treatment capacity as
well as include RO treatment of drinking water and add a second outfall to discharge the
RO concentrate. The design potable flowrate of the whole WTP will be 45 MGD (at
build -out) and with an expected wastewater filter backwash discharge from the
conventional treatment into Hood Creek of 3.9 MGD (at build -out) and an expected RO
wastewater discharge of 0.7 MGD (minimum) to 5.0 MGD (maximum designed) into the
Cape Fear River. The facility will generate discharge continuously of the reject water
concentrate from the RO treatment process. The source water will be surface water drawn
from the Cape Fear River. Discharge from the RO treatment through Outfall 002 is
expected to begin October 1, 2020.
Potable water and wastewater treatment at 45 MGD build -out will consist of:
• Two (2) 24 MGD rapid mix basins
• Four (4) high rate clarifier basins
o Clarifiers modified for air scour and pumped backwash to provide solids
and particulate removal
• Sixteen (16) dual media (sand and anthracite) granular media filters
o Filters modified for air scour and pumped backwash to provide solids and
particulate removal
• Two (2) clearwells
• One (1) 4 MGD backwash equalization and decant basin
• Two (2) 80-ft diameter sludge thickeners
• Dechlorination
• Eight (8) 5.15 MGD reverse osmosis skids
• Surface water discharge (Outfall 001)
• Submerged streambank discharge (Outfall 002)
• Conventional treatment chemical usage will consist of:
o Chlorine dioxide (pre -oxidant and primary disinfectant)
o Chlorine (pre -oxidant)
o Powdered activated carbon (PAC) for taste and odor control
o Polyaluminum chloride (PAX) as a coagulant
o Caustic soda for pH adjustment
o Coagulant aid polymer
Page 2 of 54

o Sodium fluorosilicate for fluoridation
o Orthophosphate for corrosion inhibition
o Chloramines (chlorine plus ammonia) for distribution system residual
o Calcium thiosulfate
• Reverse osmosis treatment chemical usage will consist of:
o Sodium bisulfate
o Antiscalant
o Carbon dioxide
o Emulsified lime
o Alkaline or acid solution (for membrane cleaning) - Spent cleaning
solution will be neutralized ahead of disposal, and typically disposal will
include blending the neutralized solution with concentrate and
discharging. Occasionally, detergents may be used as part of the cleaning.
When they are used, the neutralized solution may be hauled separately to
the Northeast WWTP.
No treatment of the waste stream is planned. Discharge will be via a diffuser into the
Cape Fear River.
Section 3. Cape Fear Basinwide Water Quality Plan:
The 2005 Cape Fear River Basinwide Water Quality Plan was reviewed. The Cape Fear
River at the proposed discharge location [Stream Segment: 18-(63)b] is not subject to a
TMDL according to the DWR Modeling and Assessment Branch website, but the basin
plan states the Division is developing a TMDL to address the low DO. The basin plan
indicates the Cape Fear River at AU number 18-(63)b (from Bryant Mill Creek to
Toomers Creek; the proposed discharge location is in this segment of the stream) is not
rated for aquatic life with dissolved oxygen < 4 mg/L in 8.8% of samples collected at site
BA589, 13.8% of samples collected at site BA639, and 11% of samples collected at site
BA640. The plan states the classification of C, Sw indicates natural swamp
characteristics.
More recent Cape Fear Basin planning data was reviewed as well. The 2018 Integrated
Review (IR) Summary Sheets AMSC Coalition with agency contains summary
information from ambient monitoring system stations from 2012 through 2016 as part of
a Basinwide Assessment Report. Three stations that fall into the stream segment 18-(63)b
(where the proposed discharge location is) were reviewed. During this time, 6.1% of
samples did not meet the evaluation level for DO of < 4 mg/L for monitoring station
B84650000 (formerly BA589), 8.2% did not for monitoring station B9020000 (formerly
BA639), and 9.8% did not for monitoring station B9030000 (formerly B640).
Per DWR staff, there are currently no nutrient concerns for this part of the Cape Fear
River Basin concerning WTPs. Quarterly monitoring for Total Nitrogen and Total
Phosphorus has been included for outfall 002 per the 2009 membrane WTP strategy.
Downstream of proposed outfall 002, there are impairments for dissolved oxygen and pH.
These impairments are approximately 12-13 riverine miles downstream from the
Page 3 of 54

proposed discharge location and occur in a different surface water classification and
stream segments (class SC waters in stream segments 18-71 of the Cape Fear River and
18-77 of the Brunswick River).
Section 4. Compliance History (October 2014 to October 2019):
Outfall 001
The compliance history of the existing outfall 001 is included below.
• Failed 8 of the last 12 toxicity tests (failed 3 of the last 4)
• 1 NOV for aluminum daily maximum exceedance
• 3 NOVs for TRC daily maximum exceedances
To address ongoing toxicity issues at Outfall 001, the toxicity test will change from a
monitor only test to a Pass/Fail Limited test 1 year after discharge from Outfall 002 is set
to commence, with a compliance schedule in the interim.
Outfall 002
There is no compliance history to review for the new proposed discharge Outfall 002.
As part of the permit application process for WTPs, applicants must complete toxicity
testing and demonstrate that the effluent will pass the appropriate toxicity tests at the
dilution that is expected at the proposed receiving stream.
Brunswick County ran toxicity tests on a series of samples collected under different pilot
testing scenarios (85% efficiency and 92% efficiency; chlorine dioxide or free chlorine as
preoxidant) for the proposed Outfall 002 to the Cape Fear River. Tests were performed
using EPA test method EPA-812-R-02-013 except for two 48-hour acute tests, which
were performed using EPA test method EPA-812-R-02-012. All tests used Ceriodaphnia
dubia. The approved Instream Waste Concentration (IWC) based on the dilution model is
33.3%.
Of the 14 toxicity tests conducted for which results were submitted, 2 tests passed at the
approved IWC of 33.3% (the remaining 12 tests either did not pass at IWC = 33.3% or
the results were inconclusive). The samples collected on 7/11/2018 and 1/14/2019 had
chronic values > 90% and therefore considered passing. The sample collected on
7/11/2018 was a grab sample that was collected when no preoxidant was in use and the
pilot plant was operating at 85% efficiency. The sample collected on 1/14/2019 was a 24-
hour composite sample that was collected when chlorine was used as a preoxidant and the
pilot plant was operating at 92% efficiency. All tests that used chlorine dioxide as a
preoxidant did not pass at the approved IWC of 33.3%.
Based on these results, it is the Division's recommendation that chlorine dioxide not be
used in the treatment process as toxicity test results indicated the effluent would not pass
toxicity tests when chlorine dioxide is in use. The toxicity tests and associated results are
provided in a revised permit application received by the Division on March 12, 2019.
Page 4 of 54

Quarterly toxicity testing will be required for Outfall 002 per the 2009 WTP strategy for
membrane WTPs. The toxicity test will be a chronic Pass/Fail limited test using
Ceriodaphnia dubia with an IWC of 33.3% based on the dilution model.
Section 5. NEPAXONSI Determination for Outfall 002:
The proposed expansion and new outfall construction were subject to review by
governmental agencies under the National Environmental Policy Act (NEPA) as the EPA
WIFIA program is the funding source. In a letter dated May 21, 2019, EPA issued a
determination of no effect for nineteen species and may affect but is not likely to
adversely affect five species. EPA requested USFWS and NMF to concur. In a letter with
a stamp date of June 19, 2019, the National Oceanic and Atmospheric Administration
(NOAA) National Marine Fisheries Service (NMFS) determined that the proposed
project will not likely adversely affect the NMFS Endangered Species Act (ESA) listed
species and/or designated critical habitat.
Section 6. Antidegradation Review / EAA Summary:
Outfall 001
Per NC Antidegradation Policy (15A NCAC 02B .0201), each applicant for an NPDES
permit expansion must document an effort to consider non -discharge alternatives
pursuant to 15A NCAC 02H .0105(c)(2). DWR staff requested an Engineering
Alternatives Analysis (EAA) be completed for Outfall 001 as the facility is expanding
and 3.9 MGD is the expected wastewater volume at the full 45 MGD build -out.
Connecting to an existing WWTP: Brunswick County stated that discharging the waste
stream from the facility to an existing sewer is not feasible as no municipal WWTPs
within a 10-mile radius provide sewer service in the area, and the Northeast Brunswick
WWTP that could expand does not have the land available to do so.
Land application: Brunswick County states the required acreage, capital costs, and
operating costs to implement a slow rate treatment of the treated process waste renders
this alternative infeasible, and the soils present are not suitable for wastewater disposal
via slow rate treatment or rapid infiltration.
Wastewater reuse: Brunswick County stated there is a lack of industrial, residential, or
commercial wastewater reuse customers in the area and the required acreage and capital
and operating costs to implement a wastewater reuse irrigation system with the treated
process waste renders this alternative infeasible.
Direct discharge to surface waters: Brunswick County stated the infrastructure for surface
water discharge is currently in place with no piping modifications required between the
facility and the outfall location, and the current infrastructure is sufficient to discharge the
proposed increase in flows.
Page 5 of 54

Cost evaluation: Brunswick County evaluated the economic feasibility of several
alternatives. Connecting to an existing WWTP was based on annual sewer use fees alone
(present value cost analysis [PVCA] of $15.3 million over 20 years), and with additional
capital costs potentially necessary for infrastructure to discharge to nearby WWTPs, this
alternative was determined to be cost prohibitive. Land application and wastewater reuse
were not considered feasible as 650-670 acres would be required ($26 million to $26.8
million for land purchase alone) plus capital costs and O&M costs (PVCA of $55.6
million to $56.7 million over 20 years), making this alternative cost prohibitive.
Discharge to surface waters at the existing outfall location into Hood Creek is estimated
to have no capital costs as infrastructure is already in place (PVCA of $12,625,658 over
20 years), deeming discharge to surface waters as the only feasible option.
Outfall 002
Per NC Antidegradation Policy (15A NCAC 02B .0201), each applicant for an NPDES
permit expansion must document an effort to consider non -discharge alternatives
pursuant to 15A NCAC 02H .0105(c)(2). This alternatives evaluation was submitted as
part of the EAA for the permit modification. DWR staff reviewed both the flow
justification as well as the alternatives analysis. DWR staff concur with the projected
flow needs based on a 40-year plan. Brunswick County serves the Towns of Bald Head,
Caswell Beach, Holden Beach, Leland, Navassa, Oak Island, Ocean Isle Beach, Shallotte,
and Southport, as well as Brunswick Regional (H2GO), Little River Water Company
(emergency use only), Northwest, 15 industrial customers, and individual retail
customers in unincorporated towns. The County experienced an average 3% annual
growth rate over the past seven years, with a near doubling of daily demand occurring
between winter and peak summer conditions.
Brunswick County completed an Engineering Alternatives Analysis (EAA) as part of
their permit application/modification request. Several alternatives were evaluated,
including connecting to an existing wastewater treatment plant (WWTP), land
application, wastewater reuse, and direct discharge to surface waters. These alternatives
are discussed below.
Connecting to an existing WWTP: Brunswick County evaluated connecting to an existing
WWTP, but stated this was not a feasible option as none of the municipal WWTPs within
a 10-mile radius provide sewer service in the area of the WTP nor do they have the
permitted capacity to accept the volume of the proposed waste stream. In additional
information provided, the County also stated the nature of the waste stream would not be
desirable for acceptance at WWTPs. Letters from these WWTPs denying acceptance of
the waste stream were provided to DWR.
Land application: Brunswick County states that available land is being used for
residential developments and that the WTP site is limited to 200 acres, and that
calculations based on low rate wastewater land application indicate approximately 1,200
acres would be required to apply 5 MGD. Soils present at the site are not suitable for
wastewater disposal via slow rate treatment or rapid infiltration. The County states that
the required acreage, capital, and operating costs to implement a slow rate treatment
makes this an infeasible alternative.
Page 6 of 54

Wastewater reuse: Brunswick County states they operate over 25 miles of reclaimed
water force mains that supply reclaimed water for irrigation to 11 golf courses and 1,040
acres of tree and turf farms. However, they state this option is not feasible as there is a
lack of industrial, residential, or commercial wastewater reuse customers in the area
adjacent to the facility, and the infrastructure required to convey reclaimed water to
customers is not currently in place.
Direct discharge to surface waters: Brunswick County evaluated the proposed discharge
location into the Cape Fear River. The County believes sufficient dilution will be
available at the proposed discharge location to handle the waste stream and is the
recommended discharge option. The County states alternate locations were considered
but the length of the pipeline was considerably longer for each option.
Additional alternatives evaluated: Brunswick County stated that there was no possible
combination of disposal alternatives. The County stated they reviewed options for all
waste streams generated by the WTP and will continue to explore options in the future.
Brunswick County also evaluated deep well injection and determined this was prohibited
by NCGS 143-214.2(b), therefore not a viable alternative for the RO concentrate.
Cost evaluation: Brunswick County evaluated the economic feasibility of several
alternatives. Connecting to an existing WWTP was not considered feasible based on
annual sewer use fees alone ($21.7 million over 20 years). With additional capital costs
potentially necessary for infrastructure to discharge to nearby WWTPs, this alternative
was determined to be cost prohibitive. Land application and wastewater reuse were not
considered feasible as 1,200 acres would be required for reuse irrigation ($50 million for
land purchase alone) plus capital costs and O&M costs. In addition, there is a lack of
wastewater reuse customers in the adjacent area and there is no infrastructure currently in
place to convey reclaimed water to customers. Therefore, discharge to surface waters was
deemed the only feasible option. Discharge to surface water at the proposed outfall
location in the Cape Fear River is estimated to have a present value cost analysis (PVCA)
of $12,625,658.
Section 7. Summary of Dilution Model Submitted for Outfall 002:
Per the dilution memo approval from DWR staff dated 8/12/2019:
CDM Smith has submitted a CORMIX model on behalf of Brunswick County to evaluate
wastewater dilution for a proposed reverse osmosis WTP discharging to the Cape Fear
River (classified: C, Swamp, PNA) approximately three miles below the confluence with
Hood Creek. The WTP will have a requested maximum 5.0 MGD RO concentrate
discharge.
The CORMIX model was submitted using the system's Unsteady Ambient Currents
function due to tidal influences on the Cape Fear River at this location. Flow values were
obtained from USGS gage 02105769 at Lock and Dam #1. Field and laboratory samples
were taken to categorize the ambient conditions and calibrate the model parameters. A
bathymetric survey showed the presence of sand waves in the river bottom and was used
Page 7 of 54

in determining discharge port depth. Multiple model runs were performed to characterize
discharge characteristics at various river flows and tidal effects. A duck -bill single port
diffuser was chosen to optimize discharge dilution over seasonal high and low flows.
The pollutants of concern are dichloroacetic acid with an estimated concentration of 35
µg/L. Target dilution needed to meet the dichloroacetic acid limit and establish a mixing
zone is 3:1. The CORMIX model results show that the standard is met a little more than 5
meters downstream within the near -field. The Division approves the following
specifications:
Target Dilution - 3:1
IWC% - 33.3%
Diffuser - single port duck -bill diffuser, approximately 12 feet deep and 6 feet from the
bank, oriented perpendicular to flow.
Regulatory Mixing Zone - 10 feet radius around the diffuser
Total dichloroacetic acid limit - 37.5 µg/L
Additional mixing zone considerations - Dilution of up to 10:1 would result in a mixing
zone ± 20 feet longitudinally from the outfall and 30 feet laterally.
No acute regulatory mixing zone is authorized by this model and evaluation
Section 8. RPA for Conventional Treatment (Outfall 001— Hood Creek):
Maximum monthly average discharge between September 2016 and August 2019 was
approximately 1.487 MGD. Parameter data reviewed between February 2015 and August
2019. Outfall 001 discharges to a stream with a 7Q l0s of 0.07 cfs.
• Copper — RP shown; monthly monitoring applied with limits
o Existing permit limits updated to be stricter
• Fluoride — no RP shown, but predicted max > 50% of allowable Cw; quarterly
monitoring maintained
o Existing permit limits removed
• Zinc — no RP shown, predicted max < 50% of allowable Cw; monitoring removed
as no RP and facility indicated zinc orthophosphate does not have the potential to
be discharged (per the previous renewal application)
• Aluminum — RP shown; monthly monitoring applied with limits
o No cancer endpoint; used NC in -stream target values for surface waters
for fish consumption
o Existing permit limits updated to be stricter
Section 9. RPA for RO Treatment (Outfall 002 — Cape Fear River):
Monitoring data provided with the permit application was reviewed. Pilot study effluent
data was provided for 1 sample collected on October 16, 2018. Additional data was
Page 8 of 54

provided for samples collected on February 26, 2018, March 26, 2018, and May 24, 2018
at 85% efficiency and 92% efficiency.
A maximum discharge of 5.0 MGD was used to calculate limits, as this is the maximum
designed discharge. A dilution of 3:1 (IWC = 33.3%) was used based on the approved
dilution model. As the discharge is to PNA waters, the HQW option was selected.
• Arsenic — No RP, predicted max < 50% of allowable Cw; monthly monitoring
applied as no data exists for the proposed outfall and arsenic is a parameter of
concern per membrane WTP strategy
• Chlorides — RP for limited dataset (n < 8 samples); no data exists for the proposed
outfall and chloride is a parameter of concern per membrane WTP strategy;
monthly monitoring with limits applied
• Copper — No RP, predicted max >_ 50% of allowable Cw; monthly monitoring
applied as no data exists for the proposed outfall and copper is a parameter of
concern per membrane WTP strategy
• Fluoride — RP for limited dataset (n < 8 samples); no data exists for the proposed
outfall and fluoride is a parameter of concern per membrane WTP strategy;
monthly monitoring with limits applied
• Lead — RP for limited dataset (n < 8 samples) but none of the non -detects are
greater than the allowable Cw; no data exists for the proposed outfall; quarterly
monitoring applied
• Molybdenum — No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
• Zinc — No RP, predicted max < 50% of allowable Cw; monthly monitoring
applied as no data exists for the proposed outfall and zinc is a parameter of
concern per membrane WTP strategy
• Aluminum - No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
o No cancer endpoint; used NC in -stream target values for surface waters
for fish consumption
o Run at 10:1 dilution as in -stream target value is a chronic value
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/l (summer) and 1.8 mg/l (winter). Acute ammonia limits are
derived from chronic criteria, utilizing a multiplication factor of 3 for Municipals and of
5 for Non -Municipals.
The updated outfall design and dilution modeling (letter date of February 14, 2019) for
outfall 002 showed the following ammonia nitrogen concentrations measured during the
pilot study:
• April 2018 (85% efficiency): < 0.2 mg/L
• April 2018 (92% efficiency): < 0.4 mg/L
• October 2018 (85% efficiency): < 0.2 mg/L
• October 2018 (92% efficiency): < 0.4 mg/L
• January 2019 (92% efficiency): < 0.2 mg/L
Page 9 of 54

Ammonia nitrogen concentrations allowed according to the attached NH3/TRC waste
load allocation (WLA) for the proposed discharge of 5 MGD with 7Q10 of 15.5 cfs (3:1
dilution) are 2.6 mg/L for summer and 5.0 mg/L for winter.
Per 15A NCAC 02B .0224, oxygen consuming wastes in high quality waters must meet
surface water quality standards of 2 mg/L for ammonia nitrogen and 6 mg/L for dissolved
oxygen. Brunswick County did not provide monitoring data for dissolved oxygen but
concluded that ammonia levels did not demonstrate an oxygen consuming waste and
therefore would not impact dissolved oxygen levels in the river.
Limitations for Total Residual chlorine (TRC) are based on the NC water quality
standard for protection of aquatic life (17 µg/L) and capped at 28 µg/L (acute impacts).
Due to analytical issues, all TRC values reported below 50 µg/L are considered
compliant with their permit limit. Proposed TRC limits for outfall 002 are based on
standard operating procedure/action level for TRC (see attached NH3/TRC WLA).
Additional parameters:
Brunswick County performed additional testing while performing their pilot study, which
DWR compared to available NC 02B standards, EPA National Recommended Water
Quality Criteria (NRWQC), and North Carolina in -stream target values for surface
waters. The samples were taken on February 26, 2018, March 26, 2018, and May 24,
2018. The pilot study was run at 85% efficiency and 92% efficiency (the efficiency at
which Brunswick County intends to run the proposed RO facility).
Parameters for which standards were available for review through an RPA are below. A
maximum discharge of 5.0 MGD was used, as this is the maximum designed discharge.
A dilution of 3:1 (IWC = 33.3%) was used for non -cancer endpoints, and a dilution of
10:1 (IWC = 10%) (annual average) was used for cancer endpoints. As the discharge is to
PNA waters, the HQW option was selected.
No cancer endpoint (3:1 dilution applied as 7010 reauired for calculations):
• 1,2,4-Trichlorobenzene — RP for limited dataset (n < 8 samples), all data points
were non detect, PQL < 1 µg/L; No monitoring required at this time as a
sufficiently sensitive test was utilized
o No cancer endpoint; used EPA NRWQC for fish consumption
• 2,4-D — No RP, predicted max < 50% of allowable Cw; monitoring not required
as not a parameter of concern per membrane WTP strategy
o No cancer endpoint; used NC in -stream target values for surface waters
for aquatic life and secondary recreation
• Atrazine — No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
o No cancer endpoint; used NC in -stream target values for surface waters
for fish consumption (human health)
• Alpha-Hexachlorocyclohexane — RP for limited dataset (n < 8 samples), all data
points were non detect, no PQL per the DWR Inorganic Chemistry Branch; No
monitoring required at this time
o No cancer endpoint; used EPA NRWQC for fish consumption
Page 10 of 54

• Bromomethane - RP for limited dataset (n < 8 samples), all data points were non
detect, PQL < 2 µg/L; No monitoring required at this time as a sufficiently
sensitive test was utilized
o No cancer endpoint; used NC in -stream target values for surface waters
for aquatic life and secondary recreation for methyl bromide as
bromomethane was listed as a synonym
• Chloroform - No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
o No cancer endpoint; used EPA NRWQC for fish consumption
• Chlorpyrifos — RP for limited dataset (n < 8 samples), all data points were non
detect, no PQL per the DWR Inorganic Chemistry Branch; No monitoring
required at this time
o No cancer endpoint; used EPA NRWQC for aquatic life
• Perchlorate — RP for limited dataset (n < 8 samples); Monthly monitoring with
limit applied
o No cancer endpoint; used NC in -stream target values for surface waters
for fish consumption (human health)
• Cobalt — RP for limited dataset (n < 8 samples), all data points were non detect,
PQL < 50 µg/L; No monitoring required at this time as a sufficiently sensitive test
was utilized
o No cancer endpoint; used NC in -stream target values for surface waters
for aquatic life and secondary recreation
• Cobalt - No RP, predicted max > 50% of allowable Cw; all data points were non
detect, PQL < 50 µg/L; No monitoring required at this time as a sufficiently
sensitive test was utilized
o No cancer endpoint; used NC in -stream target values for surface waters
for fish consumption (human health)
• Aluminum - No RP, predicted max < 50% of allowable Cw; Monitoring not
required as not a parameter of concern per membrane WTP strategy
o No cancer endpoint; used NC in -stream target values for surface waters
for fish consumption
• Alkalinity — RP for limited dataset (n < 8 samples); Monthly monitoring with
limit applied
o No cancer endpoint; used EPA NRWQC for aquatic life
• Barium — No RP, predicted max < 50% of allowable Cw; Monitoring not required
as not a parameter of concern per membrane WTP strategy
o No cancer endpoint; used NC in -stream target values for surface waters
for aquatic life and secondary recreation
• Iron — No RP, predicted max < 50% of allowable Cw; Monitoring not required as
not a parameter of concern per membrane WTP strategy and EPA approved
removal of NC aquatic life standard as part of 2007-2016 Triennial review due to
high natural occurrence in NC surface waters
o No cancer endpoint; used EPA NRWQC for aquatic life
• Manganese — RP for limited dataset (n < 8 samples); No monitoring required at
this time as EPA approved removal of NC human health standards as part of
2007-2016 Triennial review due to high natural occurrence in NC surface waters
Page 11 of 54

o No cancer endpoint; used EPA NRWQC for fish consumption (human
health)
• GenX - No RP, predicted max < 50% of allowable Cw; Quarterly monitoring
applied
o Used NC DHHS health goal value
o Monitoring data compared against chronic value so 10:1 dilution was used
o DHHS health goal value was not cut in half as there is no downstream
drinking water intake and no NC or EPA surface water standards to
compare against
• PFOA + PFOS - No RP, predicted max > 50% of allowable Cw; Quarterly
monitoring applied
o Used EPA Drinking Water Health Advisory level
o Monitoring data compared against chronic value so 10:1 dilution was used
o DHHS health goal value was not cut in half as there is no downstream
drinking water intake and no NC or EPA surface water standards to
compare against
Cancer endpoint (10:1 dilution applied as Qaveraee (annual flow averaael required for
calculations):
• Arsenic (human health) - No RP, predicted max > 50% of allowable Cw; all data
points were non detect; monthly monitoring applied as no data exists for the
proposed outfall and arsenic is a parameter of concern per membrane WTP
strategy
• 1,4-dioxane — No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
o Cancer endpoint; used NC in -stream target values for surface waters for
fish consumption (human health)
• Dichloroacetic acid - No RP, predicted max > 50% of allowable Cw; Quarterly
monitoring applied
o Cancer endpoint; used NC in -stream target values for surface waters for
fish consumption (human health)
• Bromoform - No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
o Based on a cancer slope; used EPA NRWQC for fish consumption
• Acrylonitrile — No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
o Cancer endpoint; used EPA NRWQC for fish consumption
• 1,2,3-Trichloropropane — RP for limited dataset (n < 8 samples), all data points
were non detect, PQL < 1 µg/L; No monitoring required at this time as a
sufficiently sensitive test was utilized
o Cancer endpoint; used NC in -stream target values for surface waters for
fish consumption (human health)
• 1,2-Dibromo-3-chloropropane (DBCP) — No RP, predicted max >_ 50% of
allowable Cw; all data points were non detect, PQL < 2 µg/L; No monitoring
required at this time as a sufficiently sensitive test was utilized
o Cancer endpoint; used NC in -stream target values for surface waters for
fish consumption (human health)
Page 12 of 54

• N-Nitrosodimethylamine (NDMA) — No RP, predicted max < 50% of allowable
Cw; monitoring not required as not a parameter of concern per membrane WTP
strategy
o Cancer endpoint; used EPA NRWQC for fish consumption
• Tetrachloroethylene - No RP, predicted max < 50% of allowable Cw; monitoring
not required as not a parameter of concern per membrane WTP strategy
o Cancer endpoint; used 02B WQS for fish consumption
• Benzyl chloride - No RP, predicted max < 50% of allowable Cw; monitoring not
required as not a parameter of concern per membrane WTP strategy
o Cancer endpoint; used NC in -stream target values for surface waters for
fish consumption (human health)
• Carbon tetrachloride - No RP, predicted max < 50% of allowable Cw; monitoring
not required as not a parameter of concern per membrane WTP strategy
o Cancer endpoint; used EPA NRWQC for fish consumption
• Hexachloroethane — RP for limited dataset (n < 8 samples), all data points were
non detect, PQL < 10 µg/L; No monitoring required at this time as a sufficiently
sensitive test was utilized
o Cancer endpoint; used EPA NRWQC for fish consumption
Radiological data was provided from the pilot study for the Northwest WTP proposed
RO concentrate for 1 sample collected on October 16, 2018 (results below). 15A NCAC
02B .0211 states the average annual activity level for combined Radium-226 and
Radium-228 shall not exceed five (5) pCi/L and the average annual gross beta particle
activity shall not exceed fifty (50) pCi/L. Based on the results using annual stream flow
average (Qaverage; 10:1 dilution), monitoring for radiological components is as follows:
Parameter
Value
Units
Monitor?
Reason
Maximum predicted
31.6 (pilot study value)
concentration >_ 50% of
allowable Cw of 250
Gross Beta
Maximum predicted
pCi/1
Yes
pCi/L per RPA; See
per RPA (at 10:1
Attachment I of the
dilution) = 195.92
permit for monitoring
requirements
Radium 226
< 1
pCi/1
N/A
N/A
Radium 228
< 1
pCi/1
N/A
N/A
< 2 (pilot study value)
Maximum predicted
Combined
concentration < 50% of
Radium 226/228
Maximum predicted
pCi/1
No
allowable Cw of 25
per RPA (at 10:1
pCi/L per RPA
dilution) = 6.2
Unregulated Compounds:
Brunswick County also performed additional testing for unregulated emerging
compounds while performing the pilot study. The samples were taken on February 26,
2018, March 26, 2018, and May 24, 2018. There are no NC 02B standards, EPA National
Recommended Water Quality Criteria (NRWQC), or North Carolina in -stream target
Page 13 of 54

values for surface waters with which to compare the data. However, as these are
pollutants of concern, monitoring for the following compounds will be required for
outfall 002 at a semi-annual frequency:
• Perfluorotetradecanoic acid (PFTeA)
• Perfluorotridecanoic acid (PFTriA)
• Perfluorododecanoic acid (PFDoA)
• Perfluoroundecanoic acid (PFUnA)
• Perfluorodecanoic acid (PFDA)
• Perfluorononanoic acid (PFNA)
• Perfluorooctanoic acid (PFDA)
• Perfluoroheptanoic acid (PFHpA)
• Perfluorohexanoic acid (PFHxA)
• Perfluoropentanoic acid (PFPeA)
• Perfluorobutanoic acid (PFBA)
• Perfluorodecanesulfonic acid (PFDS)
• Perfluorononanesulfonic acid (PFNS)
• Perfluorooctanesulfonic acid (PFDS)
• Perfluoroheptanesulfonic acid (PFHpS)
• Perfluorohexanesulfonic acid (PFHxS)
• Perfluoropentanesulfonic acid (PFPeS)
• Perfluorobutanesulfonic acid (PFBS)
• Perfluorooctanesulfonamide (PFOSA)
• 2-(N-ethylperfluorooctanesulfonamido) acetic acid (N-EtFOSAA)
• 2-(N-methylperfluorooctanesulfonamido) acetic acid (N-McFOSAA)
• Hexafluoropropylene oxide dimer acid (HFPO-DA / PFPrOPrA / GenX)
o Also known as 2,3,3,3-Tetrafluoro-2 (1,1,2,2,3,3,3-heptafluoropropoxy)-
propanoic acid
• Perfluoro-2-methoxyacetic acid (PFMOAA)
• 6:2 Fluorotelomer sulfonic acid (6:2 FTS)
• Nafion Byproduct 2
• Perfluoro(3,5,7,9-tetraoxadecanoic) acid
• Perfluoro(3,5,7-trioxaoctanoic) acid
• Perfluoro(3,5-dioxahexanoic) acid
Additionally, pollutants for which pilot study results of unregulated compounds for
Outfall 002 were submitted will have required monitoring (see Section 11 below). The
samples were taken on February 26, 2018, March 26, 2018, and May 24, 2018. The pilot
study was run at 85% efficiency and 92% efficiency (the efficiency at which Brunswick
County intends to run the proposed RO facility). These parameters can be found in the
following locations of the permit modification request:
• Initial application submission received in letter dated November 9, 2018
• Additional information received in letter dated February 15, 2019
• Additional information received in letter dated March 8, 2019
• Additional information received on May 2, 2019
Page 14 of 54

Section 10. Permitting Strate2y:
The existing Outfall 001 to Hood Creek has been updated following the 2009 WTP
strategy for membrane WTPs, the 2012 guidance update, and RPA.
The new proposed Outfall 002 to the Cape Fear River has been drafted following the
2009 WTP strategy for membrane WTPs and the 2012 guidance update. Total Iron is not
included for Outfall 002 as there is no longer a NC water quality standard. Parameters
included in the permit are below:
Flow
Membrane WTP strategy followed
Dissolved Oxygen
Membrane WTP strategy followed
Salinity
Membrane WTP strategy followed
Conductivity
Membrane WTP strategy followed
H
Membrane WTP strategy followed
Total Residual Chlorine
Membrane WTP strategy followed
Total Dissolved Solids
Membrane WTP strategy followed
Turbidity
Membrane WTP strategy followed
Total Arsenic
Membrane WTP strategy followed
Total Chloride
Membrane WTP strategy followed; See Section 9 of
factsheet
Total Copper
Membrane WTP strategy followed
Total Fluoride
Membrane WTP strategy followed; See Section 9 of
factsheet
Total Zinc
Membrane WTP strategy followed
Ammonia Nitrogen
Membrane WTP strategy followed
Perchlorate
See Section 9 of factsheet
Alkalinity
See Section 9 of factsheet
Total Lead
See Section 9 of factsheet
Gross Beta
See Section 9 of factsheet
Dichloroacetic acid
See Section 9 of factsheet
Total Nitrogen
Membrane WTP strategy followed
Total Phosphorus
Membrane WTP strategy followed
Total Hardness
WTP guidance followed
WET Testing
Membrane WTP strategy followed; IWC % based on
CORMIX model see Section 7 of factsheet
PFAS Compounds
See Sections 9 and 11 of factsheet
Additional Parameters
See Section 11 of factsheet and Attachment I of permit
Section 11. Special Conditions:
Section A. (6) has been added to the permit to define required instream monitoring
locations based on the approved dilution model.
Page 15 of 54

Section A. (7) has been added to the permit to require that, in accordance with 40 CFR
122.2 1 (k)(5)(vi), no later than 2 years after the commencement of discharge from the
proposed facility through outfalls 001 and 002, the applicant is required to complete and
submit items V and VI of NPDES application form 2C.
Section A. (7) also requires that monitoring be performed for outfall 002 for all
parameters listed in Attachment I. This additional monitoring represents parameters that
are not in the NPDES application form 2C, but monitoring data was submitted from the
pilot study and the parameters have NC 02B water quality standards, EPA National
Recommended Water Quality Criteria (NRWQC), or North Carolina in -stream target
values for surface waters with which to compare the data. Attachment I also includes
required monitoring of parameters that have no standards but monitoring results
submitted were above the level of detection as they are potential pollutants of concern if
NC or EPA standards are set. Monitoring will not be required for additional parameters
that monitoring data was submitted for (such as medications and food products) that are
known to be in raw water systems as the Division can require monitoring in the future.
Monitoring will also not be required for parameters that do not have NC or EPA
standards and submitted results were below the level of detection. See attachment to this
factsheet for a list of parameters.
Section A. (8) has been added to the permit to address monitoring for emerging PFAS
compounds.
Section A. (9) has been added to the permit to address disposal of spent membrane
cleaning solutions in line with treatment stated in the permit application.
Section 12. Changes from current permit to draft:
• Updated outfall map
• Updated language on the Supplement to Permit Cover Sheet for outfall 001 to
reflect current language used
• Receiving stream for outfall 001 corrected to an unnamed tributary to Hood Creek
on cover sheet and Supplement to Permit Cover Sheet per comments from CDM
Smith (permittee's representative)
• Added language on the Supplement to Permit Cover Sheet to reflect the proposed
expansion and outfall 002
• Facility grade added in A(1)
• Turbidity monitoring reduced to 2/month in A(1) for outfall 001 per the 2012
WTP guidance
• TRC limit updated in A(1) for outfall 001 based on WLA (full build -out
wastewater flow of 3.9 MGD used)
o Limit became stricter than what is in existing permit
• Limits updated for copper in A(1) for outfall 001 per the RPA
o Limits became stricter than what is in existing permit
• Limits removed for fluoride in A(1) for outfall 001 per the RPA
o Compliance schedule in renumbered A(3) updated to reflect removal of
fluoride limits for outfall 001
Page 16 of 54

• Limits removed for aluminum and monitoring reduced to quarterly in A(1) for
outfall 001 per the 2012 WTP guidance
• Monitoring for zinc removed in A(1) for outfall 001 per RPA
o Previous permit application indicated that zinc orthophosphate did not
have the potential to be discharged
• Added limited toxicity test with compliance schedule for outfall 001 in A(1) and
associated language as A(11) to address ongoing toxicity issues
o Compliance date chosen as 1 year after discharge from outfall 002 is
scheduled to commence
• Added A(2) as effluent monitoring for the proposed RO discharge outfall 002 into
the Cape Fear River and associated toxicity language as A(12)
• Compliance schedule updated in A(3) to reflect current time to compliance
deadline
• Added A(6) for instream monitoring location requirements for outfall 002
• Added A(7) to require additional monitoring at outfalls 001 and 002 after
discharge commences at outfall 002
o Condition can be removed during next renewal
• Added A(8) to require additional monitoring at outfall 002 for PFAS compounds
• Added A(9) to address disposal of spent membrane cleaning solution
• Updated eDMR language in renumbered A(13)
Section 13. Changes from draft to final:
• Language on Supplement to Permit Cover Sheet items 2, 4, and 5 updated to
clarify notification should be given 60 days prior to expanded discharge from
outfall 001 based on recommendation in hearing officer's report
• Description of wastewater discharge in A(1) has been updated to match that
described on the Supplement to Permit Cover Sheet based on recommendation in
hearing officer's report
• Added updated limits for aluminum for outfall 001 in A(1) per RPA
o Limits mistakenly removed in draft permit
o Limits became stricter than what is in existing permit
• Updated language in toxicity footnotes in A(1) and A(2) based on
recommendation in hearing officer's report
• Description of wastewater discharge in A(2) has been updated to match that
described on the Supplement to Permit Cover Sheet based on recommendation in
hearing officer's report
• Added monitoring and limits for alkalinity for outfall 002 in A(2) per RPA
o Mistakenly left out of draft permit
• Updated monitoring footnote #2 in A(2) regarding instream monitoring frequency
based on recommendation in hearing officer's report
• Updated conditions under A(1) and A(2) to match language in other permits based
on recommendation in hearing officer's report
• Removed requirement for third year report on Corrective Action Plan in A(3) as
the compliance deadline is less than 3 years from the permit issuance date based
on recommendation in hearing officer's report
Page 17 of 54

• Language in A(7) has been updated to make it clearer that monitoring is required
at outfalls 001 and 002 after expansion has completed based on recommendation
in hearing officer's report
• Added missing parameter codes for outfall 002 in A(8)
• Parameter name for HFPO-DA (GenX) changed in A(8) to reflect a more
common name
• Monitoring frequency for PFAS compounds changed from semi-annual to
quarterly in A(2) and A(8) based on recommendation in hearing officer's report
Section 14. Comments received on draft permit:
• Andrew Haines (DMF; via email 11/1/2019): We do not have any comments on
this draft permit.
• Mark Vander Borgh (DWR WSS/Ecosystem Branch; via phone 11/14/19):
Questions ahead of Cape Fear Basin Monitoring Coalition meeting
o Can monitoring frequencies can be adjusted to fit into the Coalition's
sampling schedule during summer months as it is more expensive to
launch a boat at the frequency in the permit, or can the permit be reopened
after a year or two of data is collected?
■ DWR response: The coalition is welcome to submit comments on
the draft regarding monitoring frequency and we will review them.
The Division will have to review and approve any monitoring
stations Brunswick County wishes to use to make sure they will be
representative of the stream at the point of discharge. Also, the
permit will not be for a full 5 years as it is a modification of an
existing permit — the permit will expire in March 2023.
o Would like to verify the frequency of GenX and 1,4 dioxane sampling.
■ DWR response: All PFAS monitoring will be at a semi-annual
(2/year) frequency and 1,4 dioxane must be monitored for once
during the permit cycle.
o Will samples be of the effluent or in the stream?
■ DWR response: The samples will be of the effluent and dilution
credit will be applied since Brunswick County submitted a dilution
model with the application.
• Hannah Headrick (DWR Aquatic Toxicology Branch; via email 11/22/19):
o Outfall 001 —Why is Chronic WET testing changing from monitoring
only to Pass/Fail testing on October 01, 2021?
■ DWR response: The permittee is being switched from the monitor
only to the pass/fail test due to a history of failed toxicity tests. A
compliance schedule is being given until 1 year after the start-up of
the new RO treatment to allow the facility time to address toxicity
issues in the Hood Creek discharge.
o Outfall 002 — Page 7 of 19, item 6 — Should this be labeled as "Chronic
WET testing (Ceriodaphina dubia) Pass/Fail limit test at 33.3%"?
■ DWR response: The permit will be updated in Section A. (1) to
reflect the limit test rather than the pass/fail limit so that the
Page 18 of 54

toxicity footnotes in Special Conditions A. (1) and A. (2) match
the heading of the toxicity conditions.
• Beth Eckert (Lower Cape Fear River Research Program; via email 11/25/19): It
is the intent of Brunswick County Utilities, Northwest Treatment Plant (NW
WTP), to request to join the Lower Cape Fear River Research Program (LCFRP).
Glen Walker, Water Resources Manager for Brunswick County Utilities described
their plan to install a Reverse Osmosis plant to remove PFAS from the drinking
water for Brunswick Utilities customers. During our last LCFRP meeting, a
discussion was held regarding this issue. The sampling requirements in their draft
permit add samples and locations currently not included in our MOA with the
Division of Water Resources. After a lengthy discussing, a motion was approved
for the LCFRP to make a comment on the Draft permit as follows:
o The LCFRP currently collects data based on the DWQ determined
sampling plan to provide comprehensive data for the entire lower basin.
These data can and are being used to understand the processes taking place
in the river as more stress is placed on the river by increasing use. There
would be a great benefit to having the Brunswick County NW WTP join
the LCFRP. The LCFRP has agreed to conduct the collection of DO, pH,
Cond and Temp at the two locations designated in the draft permit;
however, the requirement of twice a month collection during the winter
months from October to April would be difficult to accomplish. The
program only conducts twice a month sampling from May to September as
part of their MOA with DWR. If this sampling frequency requirement
could be amended to be consistent with the current plan in the MOA and
facilitate their participation in our program it would be appreciated.
o Additionally, footnote 5 on page 7 of their draft permit discusses the
waiving of sampling requirements for hardness if the utility joins the
LCFRP. The footnote on other LCFRP member permits waives all
ambient monitoring and does not limit it to hardness. I believe their draft
language should be amended to include waiving the required ambient
monitoring as long as membership is maintained.
■ DWR response: The Division has determined the permittee will
be required to perform monitoring at the frequency required in the
permit for two years. After 2 years, the permittee may request a
reduction in monitoring for instream parameters, after which the
Division will review all data received and determine if a reduction
in monitoring frequency may be granted.
• Dana Sargent (Cape Fear River Watch; via email 11/26/19):
o Thank you for the opportunity to comment on Draft NPDES Permit
NC0057533, sent by the North Carolina Department of Environmental
Quality to Brunswick County on October 31, 2019. On November 4, 2019
DEQ posted public notice for the draft permit and gave the public 30 days
to submit written comments. Cape Fear River Watch respectfully requests
a two -week extension of the comment deadline for the draft permit, until
December 19, 2019.
o Cape Fear River Watch is a nonprofit public interest organization
headquartered in Wilmington, North Carolina. Its mission is "to protect
and improve the water quality of the Cape Fear River Basin for all people
Page 19 of 54

through education, advocacy and action." In order to fulfill that mission,
the organization works to protect the entire Cape Fear River from
pollution, including toxic per- and polyfluoroalkyl substances ("PFAS").
Members of Cape Fear River Watch who live near, fish, swim, and boat
on; and who drink water from the Cape Fear River have already been
devastated by PFAS contamination from DuPont and Chemours'
Fayetteville Works Facility. Brunswick's new water treatment facility is a
step forward in providing safer drinking water to its customers by
removing PFAS from its intake water. However, Cape Fear River Watch
is concerned that the County's permit application does not provide enough
information about its discharge, and that the draft permit issued by DEQ
allows uncontrolled PFAS pollution from the plant back into the Cape
Fear River.
o North Carolina law requires that the public be given "at least 30 days after
the notice is published" to provide public comments to the State regarding
proposed permitting action. N.C. Gen. Stat. § 143-215.4(b) (emphasis
added). A longer comment period is warranted when a permit is of
significant public interest and the issues it presents are complex. Given the
history of PFAS pollution in the Cape Fear River, the complexity of this
permit, and the Thanksgiving holiday, Cape Fear River Watch believes
that a 30-day comment period is insufficient.
o DWR response: Thank you for submitting a request on the draft NPDES
permit for the Northwest WTP (NC0057533). In the public notice that was
published for the public hearing, the Division stated that "All comments
received by December 5, 2019 will be considered in the final
determination regarding permit issuance and permit provisions."
Therefore, any comments received prior to or at the public hearing on
December 5th will be considered in the final permit determination. Any
comments received after the close of the public hearing will not be
considered. Please let either myself or my supervisor, John Hennessy,
know if you have any questions.
• Douglas Todd (Tri-Beach Volunteer Fire Department; via email 11/29/19): The
Tri-Beach Volunteer Fire Department supports the approval of the permit for
Brunswick County for the waste water from the Northwest Water Treatment
Plant.
• Mark Vander Borgh (DWR WSS/Ecosystem Branch; via email 11/30/19):
o The Lower Cape Fear River Program (LCFRP) has four water quality
monitoring stations in the same stretch of the Cape Fear River, as the
proposed location of the WTP discharge. The LCFRP visits these stations
twice monthly from May to September and monthly from October through
April as agreed upon in the DWR LCFRP MOA. I believe the monitoring
frequency in the WTP permit should align with the LCFRP monitoring
frequency.
o The LCFRP and the WTP have been in negotiation to have the LCFRP
conduct the WTP monitoring while conducting their routine water quality
monitoring. Although the modest instream monitoring requirements of
DO, pH, conductivity, and temperature are easily measured, the logistics
of getting to the discharge location is problematic. The measurements
Page 20 of 54

must be taken from a boat, as there is no bank -side access to the
designated upstream and downstream monitoring locations. The time it
takes to calibrate the meter, get the boat in the water, navigate to the
discharge point and return to the lab for post -calibration testing will take
4-5 hours. In addition all boat runs require two staff as specified in DWR
safety protocols. Therefore, an additional half-day's work for two staff
would be required to meet the proposed permit year-round twice monthly
requirement. My concern is that the additional trips to the WTP to collect
those few measurements will be cost prohibitive and/or too time
consuming for the LCFRP to perform. Therefore, a secondary contractor
or WTP staff would collect those measurements, which would not be in
concert with the water quality monitoring currently being performed.
o The LCFRP would be conducting their water quality monitoring at the
WTP on the same day, with the same frequency, as it monitors the other
stations on the river. This would provide a comprehensive evaluation of
the WTP discharge effects on the river. Measurements of DO, pH,
conductivity and temperature at other locations in the river can be
compared to measured conditions around the WTP discharge.
Environmental conditions farther downstream than the WTP discharge can
also be evaluated.
o The current LCFRP monitoring coupled with the measurements at the
additional locations would provide the data needed to evaluate the effects
of reverse osmosis technology on the river as it removes emerging
compounds from drinking water distribution lines. I do not believe the
additional twice a month sampling for those seven months is needed to
provide the data for this evaluation.
o I would also add, the requirement for the collection of the instream
samples at the same time as the effluent samples represents other logistic
concerns. I do agree all efforts should be made to do so, but there should
be some variance that allows this to occur between field and facility staff s
schedules and work duties. I suggest the requirement be changed from the
same time to the same day.
■ DWR response: The Division has determined the permittee will
be required to perform monitoring at the frequency required in the
permit for two years. After 2 years, the permittee may request a
reduction in monitoring for instream parameters, after which the
Division will review all data received and determine if a reduction
in monitoring frequency may be granted.
• James Merritt (LNCW; via email 12/2/19): I will be unable to attend the Dec. 5
meeting but would like to offer the following: This email is to offer my support
for the Brunswick County Northwest Water Treatment Plant to obtain a NPDES
permit for the low pressure reverse osmosis treatment plant proposed. This
process appears to be the best alternative to preventing the spread of the PFAS to
the entire population served by them. I realize that the PFAS will end up back in
the river but, currently most are being returned through the waste water treatment
plants. The rest are remaining in the County, in the people, animals and soil. It
appears that this plan clearly offers a public health benefit and the area of
environmental impact will be reduced and minimal. The testing proposed will
Page 21 of 54

help understand if their and any impacts to the water quality in the river.
Hopefully, the source of these chemicals will be prevented from entering the river
by the chemical companies at some point.
• Rob Johnson (Sunset Harbor Zion Hill Volunteer Fire Department; via email
12/3/19): I am writing this email in support of the Northwest Water Treatment
Plant because I am unable to attend the public hearing on December 5. Based on
the information I have read regarding the need for this project, it appears to be in
the best interest for all to remove pollutants from the water at a rate that the
system an be keep up with and to allow for growth. Hopefully there will be
enough support and people will realize that we have a limited fresh water supply
for drinking and recreational use and our county continues to grow. It appears that
companies are discharging pollutants at a rate that our current system can not
keep up with. We need to do something now to get this under control. The
companies need to stop the pollutant discharges regardless. Any amount is to
much. We need to have clean water for good health of the citizens and to promote
growth in our county.
• Randell Woodruff (County Manager for Brunswick County; via email 12/5/19):
Please accept my comments in support of the Brunswick County Utilities
Northwest Water Treatment Plant Project. This project is so crucial to the future
growth of the County as the Utilities Department strives to serve all residents with
healthy and accessible drinking water over the next thirty years or longer. The
County has done a very thorough analysis and planning process to make sure to
have the necessary production capabilities as Brunswick continues to be one of
the fastest growing areas in the Country.
• Steve Stone (Deputy County Manager for Brunswick County; via email 12/5/19):
o As a member of Brunswick County's leadership team, I have been
involved in our review of appropriate technologies for treatment of
drinking water at our NW Water Treatment Plant. I firmly believe that low
pressure reverse osmosis (LPRO) is the best method to remove not only
the PFAS compounds that are known to be present in the Cape Fear River,
but that it is also the treatment process most likely to remove other
contaminants that may be present in the River now or in the future. While
the process will require a discharge back into the River, nothing will be
put back into the River that was not already present prior to treatment, and
the impacts to the River downstream will be negligible. In fact, it could be
argued that there will be no demonstrable downstream impacts at all as a
result of the LPRO discharge. It is the goal of Brunswick County Public
Utilities to provide the safest drinking water possible for our customers in
a cost effective means, while preserving the environmental integrity of our
surface waters to the maximum extent practicable.
o On a personal note, I live two blocks from the riverfront in Southport and
frequently am in contact with the River. I also consume water processed
by our Utility, as do my wife, six of my adult children, and eight
grandchildren. I believe that LPRO will provide my family and all of our
customers with safe drinking water well into the future, and will have no
negative impacts upon our recreational use of the River nor upon the life
within it.
Page 22 of 54

• David Stanley (Health and Human Services Executive Director for Brunswick
County; via email 12/5/19):
o I am sending this correspondence to voice my support of the Northwest
Water Treatment Plant expansion project in Brunswick County. This
project will expand the water treatment capacity from 24 mgd to 36 mgd
and add Low Pressure Reverse Osmosis advanced water treatment for the
removal of persistent contaminants such as GENX, PFOA, PFOS, etc. The
project will require modification of the existing NPDES (National
Pollutant Discharge Elimination System) permit.
o As you may know potential emerging contaminates have been front and
center in the discussion of public water providers and public health leaders
over the last several years. As such, I stand in full support of public water
supply systems being able to provide greater treatment to address these
emerging contaminates. This project is extremely important to the
continued growth in Brunswick County and to ensuring the health, safety,
and welfare of all those who live and visit Brunswick County. Please
accept this correspondence as my full support of the project and necessary
permit modifications.
• Paul Biagiotti (via email 12/5/19): I wanted to take a moment to provide a
comment regarding the Brunswick County NPDES permit modification. I am in
support of this and feel that this project is extremely important to the continued
growth in Brunswick County and to ensuring the health, safety, and welfare of all
those who live and visit Brunswick County.
• Bob Tweedy (Utilities Manager for Brunswick County; via email 12/5/19):
o As a Brunswick County resident and water customer, I am very much in
favor of the County's efforts to protect its customers by removing or
reducing contaminants present in drinking water produced at the
Northwest Plant. My friends and neighbors want to know, "Is our water
safe?"
o As the County's project manager for the expansion of the Northwest
Water Treatment Plant and addition of advanced treatment, I have fielded
many calls from people concerned about our water quality. Residents,
business owners, realtors and people interested in moving to Brunswick
County, all wanting to know, "Is our water safe?"
o My answer has been the water is as safe as it can be with the treatment
technology that is in place. Our water meets all federal and state drinking
water standards. However, as more has been learned about the
contaminants that are in the river, and in our drinking water, my answer
has evolved to include, "The water needs to be better and the County is
working to make it so."
o With the use of Low Pressure Reverse Osmosis, our water will not only be
better. It will be world -class. Low Pressure Reverse Osmosis will remove
many contaminants present that may take years of research before their
adverse effects are known, and safe levels can be determined. Why wait?
Low Pressure Reverse Osmosis can remove them now.
• Frank Williams (Chairman of the Brunswick County Board of Commissioners;
via email 12/5/19): As you are aware, Brunswick County is in the final stages of
design and permitting of the Northwest Water Treatment Plant expansion project,
Page 23 of 54

which will expand the water treatment capacity from 24 mgd to 36 mgd and add
Low Pressure Reverse Osmosis advanced water treatment for the removal of
persistent contaminants such as GENX, PFOA, PFOS, etc. The project will
require modification of the existing NPDES (National Pollutant Discharge
Elimination System) permit. I am writing in support of the requested NPDES
permit modification. I support the permit modification for a number of reasons:
o Brunswick County is a fast-growing county, and the ability to provide our
citizens with safe, clean drinking water is critical.
o Adding Low Pressure Reverse Osmosis (LPRO) advanced water treatment
will enhance our ability to remove PFAS and other contaminants from our
water source, the Cape Fear River. Ion exchange (IX) resin, Granular
Activated Carbon (GAC), and Low Pressure Reverse Osmosis (LPRO)
advanced treatment methods were determined to be the most viable
technologies capable of removing PFAS contaminants and these were
fully investigated by the water resource experts on Brunswick County's
consulting team. Pilot testing was performed using all three measures and
Low Pressure Reverse Osmosis best met Brunswick County's target
removal goals; virtually eliminating the PFAS from the drinking water at
the least cost.
o The only effective way to reduce or eliminate PFAS from the environment
is at the source. Removal of PFAS at water treatment plants is not an
effective means of remediation of the Cape Fear River because 1) water
treatment plants typically process only a tiny fraction of the water in the
source water river system and 2) this creates a substantial and widespread
economic (cost burden) and social impact on users of the water system
instead of the polluters causing the issue.
o Prior to going through the LPRO process, water will essentially be treated
to current drinking water standards using the existing conventional
treatment techniques (flocculation, filtration, chemical addition) already
available at the Northwest WTP. The LPRO process will remove
contaminants that are not readily removed by conventional water
treatment processes. This discharge will meet most drinking water
standards with few exceptions (disinfection by-products, PFAS). For
perspective, the amount of PFAS contained in one gallon of LPRO reject
discharge would be equivalent to discharging ten gallons of drinking water
to the river using current treatment methods.
o The NPDES permit modification will not increase the amount of PFAS
compounds in the environment because the Northwest WTP is not a
generator of PFAS compounds.
o Thank you for your consideration, and I urge you to support the requested
permit modification.
• Jean Zhuang (SELC; via email 12/5/19): The Southern Environmental Law
Center offers the attached written comments on Draft National Pollutant
Discharge Elimination System ("NPDES") Permit NC0057533, released by the
North Carolina Department of Environmental Quality to Brunswick County on
October 31, 2019. These comments are submitted on behalf of Cape Fear River
Watch, Clean Cape Fear, Center for Environmental Health, Haw River Assembly,
Page 24 of 54

North Carolina Coastal Federation, North Carolina Conservation Network, Toxic
Free NC, and the Cape Fear Group of the Sierra Club.
o This draft permit is the first of many that DEQ will issue related to the
ongoing crisis of per- and polyfluoroalkyl substances ("PFAS") in our
streams, rivers, and drinking water. Brunswick's project that would be
authorized by the permit is a necessary response to industry and
wastewater treatment plant failures to control PFAS upstream - and the
failure of DEQ's permitting process to identify and control PFAS
discharges. Brunswick County plans to install a reverse osmosis treatment
system at its Northwest Water Treatment Plant to remove PFAS and other
contaminants from upstream users. Brunswick's new water treatment
facility is a significant step forward in providing safer drinking water to its
customers by removing PFAS from its intake water. We support that
process, and these comments are not intended to delay or prevent the
construction of the facility. Providing clean drinking water to Brunswick
County's customers is of paramount importance.
o DEQ must also ensure that residents who fish, boat, and swim downstream
of the discharge are protected. Most of Brunswick County lies
downstream of the proposed discharge location. County residents and
visitors fish, harvest shellfish, boat, swim, and live downstream. As
discussed below, emerging research is showing that PFAS - even at low
levels - are harmful. In addition, one of the key characteristics of the class
is that they bio-accumulate, including in popular sport fish like striped
bass.
o The reverse osmosis treatment process will create a highly PFAS-
concentrated stream of wastewater that must be dealt with responsibly.
There are two key problems with this draft permit. First, neither the
application nor the permit discloses the PFAS that will be discharged or
the quantity of those PFAS. Brunswick County did not disclose its
proposed HAS discharge in its application. The public, therefore, has no
means of assessing the amount of PFAS that would be discharged by the
county or evaluating the potential threat from the chemicals.
o The second problem is DEQ's apparent failure to evaluate alternative
methods of treatment or disposal of Brunswick County's discharge that
would remove PFAS. Neither Brunswick nor DEQ appear to have
evaluated any technology capable of removing HAS from the facility's
waste stream. The draft permit fails to evaluate any limits on PFAS or to
include a process to develop future limits. In addition, the proposed
monitoring requirements are simply inadequate.
o This draft permit has been released following two and a half years of
intensive focus on PFAS contamination in southeastern North Carolina.
PFAS, a group of man-made chemicals that have been used in
manufacturing since the 1940s, are known to travel far and to be
dangerous to human health and the environment. Because of this, DEQ
must analyze Brunswick County's ability to responsibly dispose of, or
treat, its wastewater before discharging it back into the Cape Fear River.
o The agency must also ensure that upstream sources are subject to the most
stringent controls achievable under the Clean Water Act. The single best
Page 25 of 54

method to eliminate HAS from Brunswick County's concentrate is to
keep the chemicals from being discharged into the river upstream. DEQ
has the authority to prevent such discharges and must vigorously enforce
the Clean Water Act to do so as it continues to receive information about
upstream sources.
o Brunswick County has not adequately disclosed HAS in its NPDES
permit application:
■ The Clean Water Act prohibits the discharge of any pollutant
without a NPDES permit. The discharge of a specific pollutant (or
group of pollutants) cannot be permitted if it is not disclosed in a
NPDES permit application. Brunswick County failed to disclose
PFAS in its permit application to discharge its reverse osmosis
concentrate into the Cape Fear River, in violation of the Clean
Water Act.
DEQ has acknowledged that disclosure of toxic pollutants,
including PFAS, is required by the Clean Water Act and state
water quality laws. In its enforcement action against The
Chemours Company, LLC for the company's discharge of GenX
and other PFAS into the Cape Fear River, the agency stated:
• Part of the permit applicant's burden in this regard is to
disclose all relevant information, such as the presence of
known constituents in a discharge that pose a potential risk
to human health. The permit applicant is required to
disclose "all known toxic components that can be
reasonably expected to be in the discharge, including but
not limited to those contained in a priority pollutant
analysis." 15A N.C.A.C. 2H .01050) (emphasis added).
[... ] These disclosure obligations are critical, in part,
because they define the scope of the Clean Water Act's
"permit shield." While compliance with the express terms
of an NPDES permit generally "shields" the permittee from
liability for violations of 33 U.S.C. § 1311, the permit does
not shield the permittee from liability where the pollutant
being discharged was not within the "reasonable
contemplation" of the permitting agency when it issued the
permit due to nondisclosure by the permittee.
The agency further acknowledged that the company had violated
its NPDES permit and state water quality laws by "failing to fully
disclose all known toxic components reasonably expected to be in
[the company's] discharge."
DEQ's position in the Chemours enforcement case was correct.
The Clean Water Act generally prohibits discharges to streams and
rivers. The NPDES permitting program is a limited exception to
that prohibition, and discharges under the program cannot be
approved unless they are adequately disclosed. The Environmental
Protection Agency has stressed the need for disclosure of
pollutants during the permitting process:
Page 26 of 54

• [D]ischargers have a duty to be aware of any significant
pollutant levels in their discharge. [... ] Most important, [the
disclosure requirements] provide the information which the
permit writers need to determine what pollutants are likely
to be discharged in significant amounts and to set
appropriate permit limits. [... ] [P]ermit writers need to
know what pollutants are present in an effluent to
determine approval permit limits in the absence of
applicable effluent guidelines.
■ The EPA Environmental Appeals Board's decision in In re:
Ketchikan Pulp Company further emphasized the importance of
disclosure, and this decision has been adopted by the Fourth
Circuit. In Piney Run Pres. Ass'n v. Cty. Comm'rs of Carroll Cty.,
Maryland, the Fourth Circuit stated:
• The Ketchikan decision therefore made clear that a permit
holder is in compliance with the [Clean Water Act] even if
it discharges pollutants that are not listed in its permit, as
long as it only discharges pollutants that have been
adequately disclosed to the permitting authority. [... ] To
the extent that a permit holder discharges a pollutant that it
did not disclose, it violates the NPDES permit and the
[Clean Water Act].
■ In Brunswick County's NPDES permit application, the County
simply points to an attached table of pilot testing results,
"Concentrate Pilot Study Results," to describe its proposed
discharge. That table includes fewer than 30 parameters —none of
which are PFAS. This does not bring PFAS into the "reasonable
contemplation" of DEQ, the permitting agency. As such,
Brunswick County has not met its burden of disclosure under the
Clean Water Act and state water quality laws. If Brunswick were
to discharge undisclosed PFAS, it would violate the Clean Water
Act. Moreover, because of this omission, DEQ does not have the
information it needs to make a fully informed decision to issue the
permit, and the public does not have adequate information to
meaningfully comment on it. The County must disclose expected
PFAS discharges for DEQ to analyze.
o DEQ has failed to evaluate effluent limits for PFAS in Brunswick
County's draft NPDES permit.
■ Rather than evaluating limits for Brunswick County's discharge of
PFAS, DEQ proposes to require that the company only monitor for
certain PFAS twice a year. The Clean Water Act demands more.
The Act requires permitting agencies to, at the very least, evaluate
technology -based effluent limitations on the discharge of
pollutants. If these limits are not enough to ensure compliance with
water quality standards, then water quality -based effluent limits
must be included. DEQ has not evaluated any limits on PFAS.
■ Technology -based effluent limits are "the minimum level of
control that must be imposed in a permit." These limits "are
Page 27 of 54

developed independently of the potential impact of a discharge on
the receiving water, which is addressed through water quality
standards and water quality -based effluent limitations." As EPA
has recognized, "technology -based limits aim to prevent pollution
by requiring polluters to install and implement various forms of
technology designed to reduce the pollution discharged into the
nation's waters." When EPA has not issued a national effluent
limitation guideline for a particular industry, permitting agencies
must implement technology -based effluent limits on a case -by -case
basis using their "best professional judgment."
■ This case -by -case analysis for technology -based effluent limits is
routinely done for the drinking water treatment point source
category. For example, EPA conducted a case -by -case analysis for
technology -based effluent limits when issuing a general permit for
Idaho drinking water facilities. The agency similarly conducted a
facility -specific, case -by -case analysis for technology -based
effluent limits when issuing a discharge permit to the water
treatment facility in Guaynabo, Puerto Rico. EPA also conducted a
case -by -case analysis for technology -based effluent limits for a
reverse osmosis system's treatment of reject water when permitting
a Massachusetts biotech facility as well as a desalination plant.
■ To carry out the case -by -case analysis for implementing
technology -based effluent limitations, DEQ must consider
appropriate technology for the category of point source and any
unique factors related to the applicant.
■ The American Water Works Association, the "largest organization
of water supply professionals in the world," has recognized that the
industry must install technology to control PFAS. The organization
has stated that the "[r]eject water" from reverse osmosis systems
"must be treated for discharging," and that it "can be successfully
combined with [granular activated carbon]."
■ DEQ is aware of the use of granular activated carbon to remove
PFAS. On September 30, 2019, Chemours submitted to DEQ the
most recent test results from its pilot study evaluating granular
activated carbon. The results show that granular activated carbon is
capable of removing more than 99 percent of 20 PFAS. Almost all
of those PFAS were reduced to levels so low they were not
detectable in the discharge. Similarly, the Cape Fear Public Utility
Authority is installing granular activated carbon at its Sweeney
Water Treatment Plant and implementing a process that captures
PFAS on the carbon filters and replaces those filters as needed.
Spent carbon filters will then be regenerated by burning off PFAS
or disposed of in a properly permitted landfill. Despite this recent
testing data showing the effectiveness of granular activated carbon,
it does not appear that DEQ evaluated any technology -based
effluent limits for PFAS in Brunswick County's draft NPDES
permit. The county's application omitted any analysis.
Page 28 of 54

Several unique factors relate to this project. Southeastern North
Carolina has been exposed to decades of high levels of PFAS
pollution. Given DuPont and Chemours' decades of PFAS
pollution, it is unsurprising that PFAS have been found in high
concentrations in the fish and alligators in the Cape Fear River and
Wilmington areas. Samples from striped bass, a popular sport fish,
averaged 551,000 parts per trillion ("ppt") of PFAS. Samples taken
from alligators in Greenfield Lake - which is in western
Wilmington and flows into the Cape Fear River downstream of the
companies' facility - were measured as high as 419,000 ppt of total
PFAS. Not only is the aquatic environment threatened by HAS
pollution in these areas, there is a possibility that PFAS
accumulation in fish and shellfish, including oysters, can harm
people who eat them.
Other unique factors are also at issue here. DEQ is currently
engaged in implementation of a consent order with Chemours that
will significantly reduce the level of PFAS entering the Cape Fear
and, ultimately, Brunswick County's facility. In addition,
Chemours has submitted a NPDES application for its outfalls.
Implementation of technology -based limits in that NPDES permit
could substantially reduce PFAS loading to the Cape Fear.
Brunswick County has its own litigation against Chemours, which
could result in additional funding available to treat the reverse
osmosis concentrate. Last, DEQ already has sampling data
identifying other sources of PFAS in the Cape Fear Watershed and
will soon have additional data. Meaningful action to control those
sources of PFAS would also reduce PFAS levels entering
Brunswick County's facility - but only if DEQ fully enforces the
Clean Water Act. These factors must be considered by DEQ in a
case -by -case technology -based effluent limitation analysis.
In addition to analyzing technology -based effluent limits, DEQ
must ensure that water quality standards will not be violated by the
County's discharge. If there is a "reasonable potential" that water
quality standards will be exceeded, DEQ must include water
quality -based effluent limits in the permit as well. PFAS are
known to harm human health, and their discharge threatens to
violate multiple water quality standards. For instance, the state
toxic substances standard requires that:
• the concentration of toxic substances, either alone or in
combination with other wastes, in surface waters shall not
render waters injurious to aquatic life or wildlife,
recreational activities, public health, or impair the waters
for any designated uses.
North Carolina defines toxic substances as:
• any substance or combination of substances [...], which
after discharge and upon exposure [... ], either directly from
the environment or indirectly [... ], has the potential to
cause death, disease, behavioral abnormalities, cancer,
Page 29 of 54

genetic mutations, physiological malfunctions (including
malfunctions or suppression in reproduction or growth) or
physical deformities in [... ] organisms or their offspring.
■ As discussed below, many PFAS are proven to harm human health
and others are expected to be harmful. These chemicals certainly
have the potential to cause adverse health effects and qualify as
toxic substances under state law. DEQ itself has stated in its
lawsuit against Chemours that PFAS "meet the definition of `toxic
substance"' under North Carolina rules.
■ Without additional information and analysis, Brunswick County
also has not demonstrated, and DEQ cannot reasonably ensure
compliance with, North Carolina's prohibition against allowing
"[o]ils, deleterious substances, colored, or other wastes" in waters
classified as Class C waters - which include the section of the Cape
Fear River that would receive Brunswick County's discharge - "to
render the waters injurious to public health, secondary recreation,
or to aquatic life and wildlife, or adversely affect the palatability of
fish, aesthetic quality, or impair the waters for any designated
uses." DEQ has thus failed to ensure that either the toxic
substances standard or standards applicable to Class C waters will
not be violated by Brunswick County's discharge, in violation of
the Clean Water Act.
■ Therefore, DEQ must require Brunswick to disclose the type and
quantity of HAS in the proposed discharge so that DEQ can
evaluate whether or not water quality standards will be violated,
and then impose water quality -based effluent limits as necessary to
ensure compliance with standards.
o The proposed monitoring requirements are inadequate.
■ In the draft permit, DEQ requires Brunswick County to sample its
discharge for HAS twice a year. As demonstrated by data
collected by DEQ, Chemours, and Cape Fear Public Utility
Authority; PFAS levels change dramatically throughout the year.
Sampling twice per year simply cannot account for the known
variability in these pollutants. That sampling data is, therefore,
inadequate to characterize PFAS discharges. It is also inconsistent
with DEQ's monitoring requirements for other facilities that
potentially discharge PFAS or other toxic wastes. DEQ has
recently required facilities to sample monthly for HAS or 1,4
dioxane, and should require at least monthly monitoring here.
o PFAS are harmful to human health and the environment.
■ DEQ must require Brunswick County to control its PFAS
discharge because it is widely known that PFAS are a threat to
human health and the environment. Two of the most commonly
studied PFAS, perfluorooctanoic acid ("PFOA") and
perfluorooctane sulfonate ("PFOS"), have been found to cause
developmental effects to fetuses and infants, kidney and testicular
cancer, liver malfunction, hypothyroidism, high cholesterol,
ulcerative colitis, lower birth weight and size, obesity, decreased
Page 30 of 54

immune response to vaccines, reduced hormone levels and delayed
puberty.
■ EPA established a lifetime health advisory of 70 ppt for the
combined concentrations of PFOA and PFOS, in drinking water.
Since then, in June 2018, the Agency for Toxic Substances and
Disease Registry released an updated Draft Toxicological Profile
for PFOA, PFOS, and other PFAS. The report suggested that many
of the chemicals are much more harmful than previously thought.
For instance, the minimum risk levels, or the amount of a chemical
a person can eat, drink, or breathe each day without a detectable
risk to health, was determined to be only 11 ppt for PFOA, and 7
ppt for PFOS.44 Epidemiological studies show that many of these
same health outcomes result from exposure to other PFAS. Given
these harms, states like Michigan, New York, New Hampshire,
New Jersey, and Vermont have acknowledged the dangers of these
compounds and have either proposed or finalized drinking water
standards for various PFAS at 20 ppt and lower.
■ PFAS are also harmful to the environment. They have been shown
to cause harmful effects in fish, amphibians, mollusks, and other
aquatic invertebrates - resulting in developmental and reproductive
impacts, behavioral changes, adverse effects to livers, disruption to
endocrine systems, and weakened immune systems. Moreover,
they are extremely resistant to breaking down in the environment,
can travel long distances, and bio-accumulate in organisms.
o PFAS contamination is unnecessary.
■ As the crisis surrounding Chemours' discharges makes clear, once
PFAS are released into the environment, they are difficult to
contain. DEQ must use its authority to aggressively control PFAS
discharges upstream of Brunswick County's facility so as to
prevent the pollution from appearing in the facility's waste stream.
Brunswick County's treatment facility will isolate PFAS in a
concentrated stream, providing cleaner water to its customers.
DEQ must also ensure that downstream users are protected when
the concentrate is discharged back into the Cape Fear.
o Therefore, DEQ must require adequate disclosure of PFAS, evaluate
expected PFAS discharges, conduct an appropriate analysis of technology-
based- and, if necessary, water quality -based -effluent limitations, and
require at least monthly monitoring for PFAS. Again, we are committed to
the protection of Brunswick County's drinking water customers, and are
confident that can be achieved, without delay, in a way that is consistent
with the requirements of the Clean Water Act.
o DWR response: See hearing officer's report for responses to these
comments.
• Rhonda Olson (via email 12/5/19): Please move forward with approving
Brunswick County's NPDES permit as soon as possible for the following reasons.
o Brunswick County needs an NPDES (National Pollutant Discharge
Elimination System) permit modification to provide better quality water to
the customers in the region.
Page 31 of 54

Al
X
■ Brunswick County is adding Low Pressure Reverse Osmosis
(LPRO) advanced water treatment measures at its Northwest Water
Treatment Plant (WTP) due to the presence of Per- and
Polyfluoroalkyl Substances (PFAS) in our water source, the Cape
Fear River. These substances are persistent in the environment
(they do not naturally breakdown), difficult to remove from
drinking water using traditional water treatment measures, and
pose a human health risk if consumed frequently over an extended
number of years. The addition of Low Pressure Reverse Osmosis
to the treatment system will virtually eliminate these contaminants,
as well as many other contaminants, from the drinking water and
will provide higher quality drinking water to a seasonal population
of around 200,000 people. The LPRO membranes are an additional
step to the treatment process and do an excellent job of
contaminant removal (imagine taking a glass of water from your
faucet and then running it through a reverse osmosis process).
These contaminants remain in a small percentage of the source
water and this is why an NPDES permit modification is needed.
Brunswick County completed an Engineering Alternatives
Analysis for disposal of this water and determined that a return to
the river was the most acceptable alternative. The Northwest Water
Treatment Plant operates under an existing NPDES permit for
disposal of filter backwash and modifications are necessary for the
LPRO reject water addition.
LPRO (Low Pressure Reverse Osmosis) is the best advanced water
treatment process for Brunswick County.
■ Brunswick County currently uses traditional filtration and chlorine
treatment to produce potable water; but advanced treatment
methods are required to remove PFAS from the drinking water
supply. Ion exchange (IX) resin, Granular Activated Carbon
(GAC), and Low Pressure Reverse Osmosis (LPRO) advanced
treatment methods were determined to be the most viable
technologies capable of removing PFAS contaminants and these
were fully investigated by the water resource experts on Brunswick
County's consulting team. Pilot testing was performed using all
three measures and Low Pressure Reverse Osmosis best met
Brunswick County's target removal goals; virtually eliminating the
PFAS from the drinking water at the least cost.
A discharge of reject water back into the river is reasonable.
■ The only effective way to reduce or eliminate PFAS from the
environment is at the source. Removal of PFAS at water treatment
plants is not an effective means of remediation of the Cape Fear
River because 1) water treatment plants typically process only a
tiny fraction of the water in the source water river system and 2)
this creates a substantial and widespread economic (cost burden)
and social impact on users of the water system instead of the
polluters causing the issue.
Page 32 of 54

o Any PFAS or other contaminant discharges within the concentrate
discharge will be reduced as DEQ and EPA address upstream polluters.
■ The North Carolina Department of Environmental Quality is taking
action to reduce or eliminate the discharge of PFAS contaminants
by known industrial dischargers at their facilities (See
https:Hdeg.nc.gov/news/key-issues/genx-investigation for more
information). EPA has also developed an Action Plan to develop
recommendations and standards for PFAS (See
https://www.0a.goy/pfas for more information).
o LPRO is the best technology for use at Brunswick County's Northwest
Water Treatment Plant and is the most protective to human health.
■ There is no "perfect" water treatment technology — there are
drawbacks and benefits of all advanced treatment methods and all
technologies have some form of residual discharge. Ion exchange
resins must be formulated to the specific target contaminant of
concern and, with 50+ known PFAS contaminants in the Cape Fear
River, it was determined that this was not a viable alternative.
Granular Activated Carbon has the potential to be a viable option
but presents challenges for disposal of spent carbon, contaminant
breakthrough of the GAC filters at high PFAS concentrations, and
excessive GAC changeout at high PFAS concentrations. Moreover,
GAC must be paired with other advanced treatment methods
(ozone, biologically active filters, ultraviolet light) to be effective
at removing other miscible contaminants. Pilot studies showed that
for extremely low target values, or extremely high source water
PFAS levels, Low Pressure Reverse Osmosis provided the best
contaminant removal efficiency for the broadest array of
contaminants. Some states have enacted some specific HAS
Maximum Contaminant Level (MCL) values as low as 11 parts per
trillion and other states are promulgating MCLs as low as 6 parts
per trillion. Reverse Osmosis provides the best option for PFAS
removal down to these extremely low levels. There is little known
about many of the PFAS contaminants and it may take years of
ongoing research before MCLs are formulated for many of these
compounds. Brunswick County seeks to invest in a technology that
can meet these low potential future MCL requirements.
o The LPRO discharge is different than a typical Wastewater Treatment
Plant Discharge — it is similar to conventionally treated water.
■ Wastewater Treatment Plant discharges contain significant
biological constituents that tend to use available oxygen in the
water as well as some ammonia, nitrogen, and phosphorous. The
LPRO Water Treatment will not contribute these types of
contaminants. Prior to going through the LPRO process, water will
essentially be treated to current drinking water standards using the
existing conventional treatment techniques (flocculation, filtration,
chemical addition) already in use at the Northwest WTP. The
LPRO process will remove contaminants that are not readily
removed by the conventional water treatment processes, such as
Page 33 of 54

PFAS, and return them to the river. This discharge will meet most
drinking water standards with few exceptions (disinfection by-
products, PFAS). For perspective, the amount of PFAS contained
in one gallon of LPRO reject discharge will be equivalent to the
amount of PFAS in ten gallons of drinking water using current
treatment methods.
o The LPRO process will not result in reduced river flows.
■ The LPRO process does require an initial increase of raw water
because around 10% may be "rejected" by the membranes.
However, the NPDES permit will allow for this water to be
discharged back to the river (albeit further downstream from the
intake) so that there is no net increase of raw water permanently
removed from the Cape Fear River to accommodate the LPRO
process. It is typical for utilities to discharge to the same water
body from where the raw water is taken in order maintain adequate
water volume for environmental integrity of the water body and
availability for use by downstream users. Brunswick County is
subject to Inter -basin Transfer regulations and this discharge is a
factor in calculating the County's net transfer of water from the
Cape Fear River basin to other river basins within the County.
o The NPDES discharge modification will not affect the amount of PFAS in
the environment.
■ The NPDES permit modification will not increase the amount of
PFAS compounds in the environment because the Northwest WTP
is not a generator of PFAS compounds. PFAS compounds are
present in the WTP's source water taken from the Cape Fear River
and the current conventional water treatment plant processes
cannot remove it from drinking water; this means that the PFAS
compounds are being delivered to customers at the tap. Currently,
these PFAS compounds are then returned to the Cape Fear River
Basin, Lockwood Folly River Basin, Shallotte River Basin,
Waccamaw River Basin, and Greater Lumber River Basin through
irrigation, septic, and wastewater treatment plant (WWTP)
discharges. The return of the LPRO concentrate to the river is not a
net addition of pollutants to the environment (or an increase in
mass of PFAS compounds). With the proposed addition of
membrane technology, Brunswick County will be providing its
customers with the most protective advanced treatment measure
for human health. Moreover, the LPRO project will ensure that
PFAS compounds are not distributed throughout Brunswick
County's other river basins — the Lockwood Folly River Basin,
Shallotte River Basin, Waccamaw River Basin, and Greater
Lumber River Basin through the drinking water system and
associated discharges (irrigation, septic, and WWTP discharges).
o The NPDES discharge modification will not have a negative impact on
commercial fishing in Brunswick County.
■ The LPRO project will actually reduce or eliminate PFAS being
distributed to the Lockwood Folly River Basin, Shallotte River
Page 34 of 54

Basin, Waccamaw River Basin, and Greater Lumber River Basin
through the drinking water system and associated discharges
(irrigation, septic, and WWTP discharges). This means that within
these river basins, shellfish and aquatic species exposure to PFAS
will be reduced. Within the Cape Fear River Basin, the PFAS
concentration will be at background levels (the concentration
levels already within the river prior to the discharge) within
approximately 30 feet of the discharge point.
o There will not be any change to recreational uses of the water downstream
of the discharge.
■ According to the Center for Disease Control (CDC) "Bathing and
swimming in water that contains PFAS should not increase your
exposure. Washing dishes in water containing PFAS should not
increase exposure." (Agency for Toxic Substances and Disease
Registry Web site https://www.atsdr.cdc.goy/pfas/pfas-
exposure.html) The PFAS concentration will be at background
levels (the concentration levels already within the river prior to the
discharge) within approximately 30 feet of the discharge point.
o The discharge will not "concentrate" PFAS (Per- and Polyfluoralkyl
Substances) like GENX, PFOA, and PFOS in the Cape Fear River System.
■ Within approximately 30 feet of the discharge point, PFAS levels
will be at background levels (the levels already within the river).
The only effective way to eliminate PFAS from the river altogether
is to control it at the source. This is best done by not allowing
industrial producers to introduce PFAS into the river through their
upstream discharges and minimizing or eliminating the use of
PFAS products in the environment.
• Paul Calamita (AquaLaw, on behalf of Brunswick County; via email 11/29/19
and updated via email 12/5/19):
o From Page 1, the permit will expire on March 31, 2023, only 3 years from
the approximate date of issuance of the modification. We ask that the
Department consider a permit effective period of 5 years. This will save
DEQ and the County staff time by avoiding another permit action in just
three years.
■ DWR response: The expiration date of the permit is based on the
permitting schedule used by the Division, which is done by river
basin. Therefore, the expiration date of the permit will remain as is.
o Supplement to Permit Cover Sheet -- Page 2 and 3, Items 2 and 4:
Brunswick County requests Items 2 and 4 be removed from the permit. As
a minimum, the language of these items should also reference Item 1,
indicating there will be on -going discharge to Outfall 001 and that the
notification to the cited regulatory agencies should be prior to the
expanded facilities being brought online.
■ DWR response: Language will be added to specify notification
should be given within 60 days prior to commencement of
expanded discharge from Outfall 001.
o Outfall 001 comments:
Page 35 of 54

■ Clarify the Authorized Waste Streams: The introduction paragraph
on Page 5 only lists filter backwash as a waste stream that is
authorized to be discharged from Outfall 001. This sentence should
be revised to state: "is authorized to discharge wastewaters from
media filter backwash and sedimentation basins through Outfall
001." As revised, this authorization will be consistent with the
description of the authorized waste streams in the Supplement to
Permit Cover Sheet.
• DWR response: The permit language will be updated to
reflect discharge from both media filter backwash and
sedimentation basins.
■ Revise Copper Sampling Frequency to Quarterly Instead of
Monthly: We request that the proposed copper monitoring be
revised from monthly to quarterly for two reasons. First, quarterly
sampling will yield either 12 (if the permit expiration data remains
the same) or 20 results (if the permit expiration date is changed to
five years) for consideration to assess reasonable potential during
the next permit renewal. Second, quarterly monitoring will
correspond to the quarterly hardness monitoring that is also
required. If the copper monitoring remains at monthly, it will force
us to also monitor hardness monthly (which is clearly
unnecessary). If DEQ insists on monthly monitoring for copper, it
should be limited to the next three years and then cease.
• DWR response: Monthly monitoring for copper was based
on an analysis of discharge data provided to the Division,
which showed a reasonable potential to exceed surface
water quality standards. Per the Division's policy, monthly
monitoring was implemented based on this potential, and
shall remain in the permit. The monitoring frequency for
hardness will be unaffected by the monthly copper
monitoring. Monitoring requirements for copper will be
reevaluated at the next permit renewal.
■ Revise Effective Date of Chronic Toxicity Limit: Footnote 6 to
Table A(1) states the chronic WET test will become a permit limit
on October 1, 2021. Brunswick County requests this be modified
so that toxicity test will change from a monitor only test to a
Pass/Fail Limited test 1 year after the discharge from Outfall 002
commences. Preliminary scheduling indicated discharge from the
RO treatment through Outfall 002 was expected to begin October
1, 2021; however, the project schedule has been revised. The
current startup for Outfall 002 is anticipated in 2022. The delay is
due to delays in issuance of this NPDES permit as Brunswick
County is unable to receive LGC approved funding until all the
major permits are finalized. This delay is expected to impact the
authorization of the construction contract. Brunswick requests that
the date for change from a monitor only limit to an enforceable
permit limit be conditioned on the startup of Outfall 002 plus one
year. The Supplement to the Permit Cover Sheet requires
Page 36 of 54

notification of changes to DEQ prior to use of new facilities
capacity; the notification date in Item 3 — 60 days prior to the start
of discharge from Outfall 002 — could be used.
• DWR response: The toxicity footnote in Section A. (1)
will be updated to reflect the change in toxicity testing will
occur one (1) year after commencement of discharge from
Outfall 002 begins.
o Outfall 002 comments:
■ Clarify Filter Backwash: On page 6, Section A. (2) "EFFLUENT
LIMITATIONS AND MONITORING REQUIREMENTS -
OUTFALL 002" please change "filter backwash" to "reject
concentrate wastewater from reverse osmosis units" to match
references in the Supplement to Permit Cover Sheet.
• DWR response: This error will be corrected.
Page 6 Salinity and Conductivity Monitoring Requirements: While
the monitoring requirements in the draft permit match those found
in Table 2.1, Monitoring Requirements for Membrane WTPs (from
the DEQ document Changes to Water Treatment Plant Strategy
(October 2009)), the membrane facilities at the Brunswick County
Northwest WTP fundamentally differ from those at traditional
membrane plants. The Northwest WTP's influent is freshwater
from the Cape Fear River, and the discharge is to freshwater. As
has been demonstrated in the pilot plant data there is very little
accumulation of salts in the concentrate (maximum measured
conductivity was 1551 µ6/cm); ions at this concentration are so
low conductivity cannot be converted to salinity. Therefore,
Brunswick requests that the salinity and conductivity in -stream
monitoring requirements be deleted from the permit. Brunswick
requests the removal of all upstream and downstream sampling
from the permit due to:
• Tidal influence at this point in the river.
• Relevance for such data where it has been demonstrated
that the effluent has very low salinity and conductivity.
• Even if Brunswick owned a boat capable of navigating the
river, the nearest boat landings are 14 miles downriver and
18 miles upriver. This would put an undo -burden on staff to
perform this type of sampling. Moreover, additional staff
would need to be hired and trained adding to the burden for
this unnecessary sampling.
• Accordingly, the County requests that in -stream monitoring
requirements be waived as long as Brunswick County
remains a member of the Lower Cape Fear River Program.
This waiver has been provided to other NPDES permits in
the lower Cape Fear River basin.
• DWR response: Upstream and downstream monitoring
requirements will remain in the permit. The Division has
determined the permittee will be required to perform
monitoring at the frequency required in the permit for two
Page 37 of 54

years. After 2 years, the permittee may request a reduction
in monitoring for instream parameters, after which the
Division will review all data received and determine if a
reduction in monitoring frequency may be granted.
Page 6 TRC limit: We ask that the TRC limit be reevaluated based
upon the revised dilution requested below.
• DWR response: Per the Division memo dated June 19,
2003 (Total Residual Chlorine Policy for NPDES Permits),
a maximum TRC limit of 28 µg/L is allowed in NPDES
permits to protect against acute impacts. The TRC limit in
the draft permit is the maximum allowed by the Division
and was based on the approved dilution zone.
Page 6 Fluoride Limit: When the new RO facility goes online, the
location of the fluoride addition to finished water will be
downstream of the RO facility feedwater. There will be no fluoride
addition at the Northwest WTP that can reach the concentrate.
Brunswick requests that the permit limit and monitoring
requirements for total fluoride be removed from the permit.
• DWR response: The limit and monitoring requirements for
fluoride are based on pilot study data submitted with the
permit modification request, which showed the potential for
fluoride to be discharged. As such, the limit and monitoring
specified will remain.
Page 6 perchlorate limit: Brunswick does not utilize bleach
solutions and there is no reasonable potential to form perchlorate in
the process. This is especially the case when the updated dilution
value proposed below is applied.
• DWR response: The limit and monitoring requirements for
perchlorate are based on pilot study data submitted with the
permit modification request, which showed the potential for
perchlorate to be discharged and exceed water quality
standards. As such, the limit and monitoring specified in
the draft permit will remain.
Total Copper and Zinc Monitoring in the Effluent: We ask that the
Department remove the Total Copper and Zinc sampling
requirements as no copper plumbing or zinc is being used to
construct the Reverse Osmosis facility. If the Department insists on
copper and zinc monitoring, the permit should allow the
Department to terminate such monitoring at the County's request
after two years.
• DWR response: As Outfall 002 is a proposed new
discharge, monitoring shall be required per Division policy.
Monitoring requirements will be reevaluated at the time of
permit renewal based upon submitted monitoring data.
Hardness Upstream Sampling Location: Brunswick requests that
sampling for hardness in the "upstream" water be allowed to be
taken from the raw feed water for the plant. This location is a
representative of the "upstream" sampling location because the
Page 38 of 54

hardness in the Cape Fear River is reasonably constant between
Lock and Dam No. 1 (withdrawal location) and proposed Outfall
002. Matt McIver of the UNCW Center for Marine Science has
recently begun collecting data on hardness in the river and
provided via personal communication that recent hardness values
at the power plant and just downstream at the Pender County
discharge are virtually the same.
• DWR response: The location specified in the draft permit
for upstream hardness monitoring will remain as the
location of the raw water intake at Lock and Dam No. 1 is
several miles upstream from the proposed discharge
location for Outfall 002, with one major NPDES permitted
discharger between the two locations. The footnote added
to Section A. (1) waives instream monitoring reporting
requirements as long as Brunswick County remains a
member of a monitoring coalition.
Correct Representative Sampling Requirement - Bottom of Page 7:
Change from "typical" to "representative" in the following
sentence as the regulatory requirement is that monitoring data be
representative of the effluent being sampled: All samples must be
collected from a typical discharge event.
• DWR response: The conditions under Sections A. (1) and
A. (2) will be updated to be consistent with that used in
other NPDES permits.
10:1 Mixing/Dilution: The CDM Concept Design and Dilution
Modeling (revised Feb, 2019) analyzed the mixing mechanics, the
regulatory requirements and other relevant factors. CDM
concluded that a discharger -specific dilution ratio of 47:1 for the
anticipated diffuser installation is in accordance with the applicable
regulatory requirements and guidance, although the 47:1 ratio itself
was chosen based on some of the projected worst case effluent
data, and not as a limit on the extent of the actual anticipated
dilution (which is expected to be even greater). The DWR Fact
Sheet references the CDM document.
• In addressing the potential discharge of dichloroacetic acid
(DCA) at new outfall 002 the Fact Sheet cites the highest
CDM-projected effluent DCA concentration and concludes
that a "Target Dilution" needed to meet the relevant
standard is 3:1. The Fact Sheet then specifically applies the
3:1 Target Dilution. The Fact Sheet then, addressing a
number of other pollutant parameters, refers to the 3:1
dilution (and the 7Q 10 critical low flow) and concludes that
no monitoring is required except for perchlorate (for which
a numeric limit is proposed along with monthly
monitoring).
• The Fact Sheet goes on to address potential carcinogens,
referring to 10:1 dilution and the annual average instream
flow statistic. Monitoring is proposed for some but not all
Page 39 of 54

of those parameters, concluding for some that no
monitoring is needed based on DWR's WTP strategy.
Brunswick County requests that DWR utilize a discharger -
specific overall instream dilution factor of at least 10:1 for
this permit cycle, for the following reasons. First, as noted
above, the upgraded WTP facilities are not yet constructed,
there is no discharge, and the CDM projections of potential
effluent pollutant concentrations are estimates based on
pilot plant concentrations and projected feed
water/permeate ratios. Therefore, there is uncertainty in the
effluent characteristic projections which warrant allowing
more of the available dilution to be applied. Also, it is clear
that for most or all of the parameters considered, the trace
chemical constituents involved are simply a pass -through
concentration of constituents derived from the WTP intake
water from the stream. Further, there is no issue of process
generation of pollutants or discharge of traditional process
wastewaters. In fact, this is a classic case for which a
proper mixing analysis is most appropriate, as the real
concern is the localized concentrations. Note that the WTP
Strategy specifically requires (section 2.1) that new RO
dischargers must perform dilution modeling. We presume
this is in part because of the factors we note here, and we
believe that using more of the demonstrated available
mixing/dilution is particularly appropriate and necessary
here.
DWR's mixing zone policy supports the specification of
dilution or mixing zone parameters, particularly in cases in
which an effluent diffuser is proposed. Mixing Zones in
North Carolina at p. 2 (DWR July 23, 1999). Note also that
there may be pollutant parameters for which the application
of a 3:1 dilution (out of the 47:1 available) may indicate
reasonable potential, though again related to the pass -
through point noted. This is where the CDM
recommendations are most helpful. Because of the
uncertainty in the effluent parameter projections, and
because of the nature of the pollutant parameters
themselves, we request that DWR use a dilution factor of at
least 10:1 for this permit cycle. That would of course
assume the installation and operation of the diffuser as
projected in the CDM report. A 10:1 dilution ratio still
provides an extremely high level of conservatism, and
correspondingly high confidence in water quality
protection. We also ask that the draft numeric limits for
total chloride, total fluoride and perchlorate be reconsidered
in light of the dilution, and either deleted in favor of routine
monitoring or amended in light of dilution.
Page 40 of 54

• Finally, the mixing zone does not accommodate the effects
of concentrating contaminants present in the raw water
supply using the RO membranes. Brunswick County is
expected to operate the membranes at permeate recovery
rates ranging from 85% to 92%, with a target recovery of
90%. At this level of efficiency, an in -stream dilution of
10:1 will be required to achieve background levels of
contaminants present in the raw water supply. Examples of
compounds fitting this description include fluoride and
unregulated chemicals such as many of the PFAS
compounds present in Brunswick County's raw water.
Brunswick County requests a mixing zone achieving at
least a 10:1 target dilution for maintaining compliance with
existing regulatory requirements and reserves the right to
request some of the additional available dilution in future
permit renewals should that be necessary to address future
water quality standards for other chemicals (again, most
likely present in the County's raw water supply).
• DWR response: The mixing zone approved by the
Division was based on information provided during the
permit modification request. The Division -approved
dilution of 3:1 will remain in the permit. As such, limits for
total chloride, total fluoride, and perchlorate will remain as
specified in the draft permit as the limits were based on the
allowed dilution and reasonable potential analysis. A
reevaluation of all permit limits will be conducted at the
next permit renewal.
■ Section A(6) Instream Sampling Locations: The locations
proposed for sampling instream water quality are problematic.
First, the permit is unclear where the preferred sampling stations
are located as only their longitudinal and vertical locations
(relative to the main flow of the river) are described. The lateral
distance into the river for sampling is not described.
• If the intent of monitoring is to sample upstream conditions
and then recently discharged effluent at the edge of the
mixing zone, these locations will be difficult to determine
in the field because the proposed discharge at Outfall 002
has been designed to jet the discharge toward the middle of
the river, and its trajectory will bend slightly based on the
river's current, which depends on the tidal stage and the
river's flow rate. And even if the location can be
determined, it will be hard to maneuver the boat to that
location and then hold the boat on station during the several
minutes it will take to lower the multiparameter probe,
equilibrate it at the target vertical sampling depth, and
collect the sample readings; personal conversation with
Matt McIver whose organization will conduct the sampling
indicates that dropping an anchor will not be possible at all
Page 41 of 54

sampling dates due to currents or at all if the locations are
close to the shore where the anchor would have a great risk
of being caught on snags. Further, given the close
proximity of the upstream and downstream sampling
locations (20 longitudinal feet), Brunswick County is
concerned about the ability to obtain representative
upstream and downstream samples given the dynamic
nature of the plume, potential for boat drift while "on a
sampling station," tidal nature of the location, and the
multiparameter probe being swept in the down -current
direction from vertical.
• While the County understands that this sampling is
grounded in the requirements of the WTP permitting
strategy, it is important to note that the Outfall 002
concentrate will not contain temperature, pH, salinity or
conductivity, dissolved oxygen or oxygen demanding
substances, to be significantly different from the river. The
report Concept Outfall Design and Dilution Modeling for
the Northwest Water Treatment Plant's Concentrate
Discharge provides data on pH, TDS, and BOD for
reference.
• Accordingly, the County requests that in -stream monitoring
requirements be waived as long as Brunswick County
remains a member of the Lower Cape Fear River Program.
This waiver has been provided to other NPDES permits in
the lower Cape Fear River basin.
• DWR response: Upstream and downstream monitoring
requirements will remain in the permit, and removal may
be evaluated at the next permit renewal based upon
monitoring data. The Division will agree to a waiver of
instream monitoring reporting requirements as long as
Brunswick County remains a member of a monitoring
coalition. It is the Division's understanding that the Lower
Cape Fear River Monitoring Program intends to perform all
instream monitoring at the locations specified in the draft
permit.
o Additional comments:
■ Section A. (3): The copper compliance schedule requires achieving
the limit by April 1, 2022, which is approximately 2 years and 5
months from the date the draft permit was issued. Therefore
provision A. (3).3, which requires reporting 3 years from the
effective date of the permit is not needed and should be removed
from the permit.
• DWR response: The third year was included as the
compliance deadline was over 2 years away, thus by
including the third year allowing Brunswick County time to
further report to the Division actions being taken. The
permit language will be updated to remove the third year.
Page 42 of 54

■ Section A. (7) Reporting Requirements after Commencement of
Discharge: This section requires Brunswick County to complete a
requirement 2 years after commencement of discharge for Outfall
001. Outfall 001 is currently in service. Please remove this
requirement from the permit.
• DWR response: This requirement will remain as the
facility is expanding and this additional monitoring will be
required after expansion has completed. The permit
condition will be updated to reflect this.
■ Section A. (8) Reporting Requirements for Emerging
Contaminants: The Northwest WTP is not a generator of the PFAS
compounds required for monitoring in this section of the draft
permit. PFAS compounds are present in the WTP's source water.
With the proposed addition of membrane technology, Brunswick
will be providing its customers with the most protective advanced
treatment measure for human health. The current treatment process
allows PFAS to be delivered to customers and is then returned to
the Cape Fear River Basin, Lockwood Folly River Basin, Shallotte
River Basin, Waccamaw River Basin, and Greater Lumber River
Basin through irrigation, septic, and WWTP discharges. The return
of the concentrate to the river is not a net addition of pollutants to
the environment (or an increase in mass of PFAS compounds) over
the concentrations that were present in the raw water. It is
requested that the permit language acknowledge that the discharge
does not result in a net increase into the environment and is
therefore not a pollutant addition. Moreover, it is requested that all
PFAS monitoring be eliminated from the permit since 1) the
Northwest WTP is not a producer of PFAS, 2) PFAS
concentrations within the river are known through raw water
testing and DEQ sampling, and 3) pilot testing confirms that
essentially all PFAS in the raw water are removed by the LPRO
process.
• DWR response: As indicated by monitoring data
submitted with the permit modification request, PFAS
compounds are present in the wastewater discharged to the
Cape Fear River. As the wastewater discharge from the
facility contains these compounds, monitoring will be
required.
■ Section A. (9) Disposal of Spent Membrane Cleaning Solutions:
The last sentence of this section should be clarified to add the
words in all capital letters that ".....and discharge of the solution
WITH DETERGENTS to surface waters is not authorized under
this permit."
• DWR response: This clarification is stated earlier in the
sentence as "When use of detergents is used with
membrane cleaning solutions..." therefore no changes are
required.
Page 43 of 54

Page 16, item 1. Remove inapplicable reporting requirements: The
draft permit requires the permittee to submit reports on (1) sewer
overflows and bypass events, (2) pretreatment program reports and
CWA section 316(b) reports. These reports are not relevant to a
water treatment plant and should be removed from the permit.
• DWR response: All language in Section A. (13) will
remain as it is standard language used in all NPDES
permits. The permittee shall follow all applicable
requirements.
Oral comments received at Public Hearing held on December 5, 2019:
See the Northwest WTP Hearing Officer's Report for responses to the comments below.
• Chris Harrelson (Brunswick County Health Services): As Brunswick County's
public health director, I wholeheartedly support the addition of low-pressure
reverse osmosis to the Northwest Water Treatment Plant. This system is designed
to remove new and emerging contaminants in the water supply, and thus will be a
welcome tool for the protection and preservation of public health in Brunswick
County.
• Reed Barton (CDM Smith): I'm a North Carolina resident and a licensed
professional engineer and I work with CDM Smith as a principal environmental
engineer. I have considerable professional experience in topics of water supply
and treatment, as well as the protection of the environment.
o A recent Harvard study found that the State of North Carolina is number
three in the nation with respect to PFAS contamination. The majority of
the known PFAS issues within North Carolina can be found within the
Cape Fear River Basin, a basin that covers 20% of the land area of North
Carolina and serves as a drinking water source to many, including the
citizens here in Brunswick County.
o In 2017, Brunswick County and the greater population of this area learned
of the presence of GenX and PFAS in the Cape Fear River. Significant
water quality and public health issues [ph]. Further, it was discovered that
these chemicals were not removed by conventional water treatment
methods that were currently in place at the county's Northwest Water
Treatment Plant. The county immediately began to work on a solution
and, shortly after, enlisted the assistance of CDM Smith to work with the
county staff on this effort.
o The team thoroughly assessed the full range of possible treatment
solutions and ultimately selected low-pressure reverse osmosis, or what
I'll refer to as "RO," as the best approach to remove these chemicals from
the drinking water, thereby protecting public health. And that is why we
are here tonight. Brunswick County would like to construct an RO
treatment facility at the Northwest Water Treatment Plant to remove GenX
and other chemicals that are found in the Cape Fear River. In order to do
this, they must receive approval, the associated NPDES permit [ph].
o Here's how the proposed process will work. Water from the Cape Fear
River will be treated in the same conventional process that is used today at
Page 44 of 54

the Northwest Water Treatment Plant. However, then water will be treated
by a final step: a new reverse osmosis filtration system. As is the case with
most municipal surface water treatment systems, there will be a side
stream of water that would need to be returned to the raw water source, the
Cape Fear River.
o It will be conveyed back to the Cape Fear River, to the proposed NPDES
permitted outfall, where it will mix back with the Cape Fear River water.
It's important to note that there are no drinking -water intakes located
downstream of the proposed outfall location. The addition of low-pressure
RO treatment at the Northwest Water Treatment Plant has been
extensively studied by experts in the fields of water and environmental
science, and without a doubt, offers the best solution for the reduction of
PFAS below very low thresholds such as those being approved or
promulgated in other states, and those desired by the city - by the citizens
of Brunswick County.
o Low-pressure RO is the best option for protecting public health as well as
having no negative impact on the environment, and I urge NCDEQ to
approve the proposed NPDES permit, thereby allowing the citizens of
Brunswick County to have pristine and safe drinking water.
• Donald Dixon (Deputy Director, Brunswick County Wastewater Operations): I
am the deputy director of wastewater operations for Brunswick County and I'm a
lifelong county resident. As has already been said, water quality is not only an
issue for our current residents due to the promulgation of these unregulated
contaminants, but as deputy director of utilities, I have received numerous calls
from potential residents not even living in the area yet, asking the same questions
that have already have been brought up. Is our water safe?
o Home building in our area is one of the drivers of our economy, and if we
don't do something to remove these contaminants, we are effectively
telling people that live outside of our area that there could be an issue here
and I think if it's part of that and if we want to continue to see that the -
you know, our coast is a beautiful place and people move here and the
businesses that could be affected by this, and all of the ancillary services
that have developed along with this growth. If we want to see these things,
then we need to remove these contaminants from our water supply.
o And in conclusion, as a public utilities staff member, I want to see us
provide the most effective technology for removing these contaminants.
As a resident, I see the need for us to the same thing.
• Emily Donovan (Clean Cape Fear): I represent Clean Cape Fear. We are a
grassroots community group that is fighting to protect public health related to
PFAS exposure and PFAS contamination, largely coming from DuPont and
Chemours via the Cape Fear River.
o I'm also a private citizen that lives in Brunswick County, where I have
been raising my 10-year-old twins. We moved here when I was pregnant,
so they have lived their whole lives on this water supply. A couple of
things that I would like to point out. This is a public health issue. This is
an emergency in our community. We have been overexposed to these
toxic chemicals. An NC State study recently estimated that we were
consuming, on average, 130,000 parts per trillion of total PFAS into our
Page 45 of 54

Lock and Dam 1 intake, which was essentially equating to what was
coming out of the finished tap water in all three counties' water supplies.
o We are overexposed. We cannot afford one more drop. And so when the
engineers came from CDM Smith, they did assessments in New Hanover
County and Brunswick County, and it was agreed that the reverse osmosis
was the best solution for this county, whereas another filtration option was
better for CFPUA in New Hanover County.
o What we desperately need is DEQ to act with the same sense of urgency
that I feel for my children and the same sense of urgency that I know this
county feels for its citizens. We need you to approve this permit quickly.
However, we also need you to approve this permit accurately, and so I
signed onto a letter with Southern Environmental Law Center, which
hopefully you have received in your inbox at least sometime today. Please
review that, because what we are requesting that DEQ do is every permit
that you issue that is a discharge permit should include PFAS in a
monitoring capacity, and that is not on your permit currently. We ask that
you amend that.
o We also ask that you increase monitoring from two times a year to once a
month. There are also other items within that letter that I would like for
you to reference. Even though this is a drinking water permit, it is still a
discharge permit, and this sends a clear and strong message to all
dischargers along the Cape Fear River that PFAS needs to be regulated
and it needs to be monitored. And I, as a Sunday school teacher and a faith
leader, firmly believe in the value system that I want to do onto others as I
would like done to myself, that I want to love my neighbors as I love
myself, and I don't think I could sleep at night if I knew that the drinking
water that I was bringing in was causing harm on the outside with the
concentrations, if I was an upstream utility.
o And I think Brunswick County has a unique opportunity to set the shining
example for the state on how a permit is written and how it is executed,
and I believe that the county can do that. There may not be a downstream
intake from the discharge but there is recreational use. There is fishing.
There is shrimping. And these chemicals biomagnify, and there's plenty of
studies that can back that up and we - I think they're listed in the SELC
letter, so I encourage you to read that fully.
o It's also important to know when I say that we've been overexposed and
we can't afford one more drop, that it is really important that this permit,
these items get attached to the permit, but that the permit also gets
approved as quickly as possible. I know that the permit was submitted a
year ago. And we really need this plant to be built quickly. There are lives
on the line. I have friends who are losing their bladders and are now
having to live with a bag. That's not a way to live. I have friends who have
colon cancer, who have brain tumors. There are children who have died in
our county. It is really time to act and we need DEQ to work as a partner
to do this, so I encourage you to use your capacity to educate yourself on
PFAS chemicals, make sure that every permit that you use and write
includes PFAS monitoring.
Page 46 of 54

o You don't need to wait on the EPA for that information. The precedent has
already been set from the consent order that was signed by DEQ and
Chemours earlier this year.
• Bob Tweedy (Senior Utilities Manager, Brunswick County Public Utilities): I'm
a county resident and I'm also an employee of the county. I'm the senior utilities
manager in charge of CIP and infrastructure. As a Brunswick County resident and
water customer, I'm very much in favor of the county's efforts to protect its
customers by removing or reducing contaminants present in drinking water
produced at the northwest plant. Our friends and neighbors want to know, is our
water safe?
o As the county's project manager for the expansion of the Northwest Water
Treatment Plant, I have fielded many calls from people concerned about
our water quality. Residents, business owners, realtors, and people
interested in moving to the county, all wanting to know, is our water safe?
My answer has been the water is as safe as it can be with the treatment
technology that is in place. Our water meets all federal and state drinking
water standards. However, as more has been learned about the
contaminants that are in the river and in our drinking water, my answer
has evolved to include the water needs to be better and the county is
working to make it so. With the use of low-pressure reverse osmosis, that
water will not only be better, it will be world -class.
o Low-pressure reverse osmosis will remove any contaminants present that
may take years of research before their adverse effects are known and safe
levels can be determined. Why wait? Low-pressure reverse osmosis can
remove them now.
• Glenn Walker (Water Resources Manager, Brunswick County Water Resources):
I'm the water resources manager for Brunswick County Public Utilities. So as Ms.
Donovan mentioned, research completed by Dr. Detlef Knappe and Dr. Mei Sun
at North Carolina State University in 2016 and 2017 determined that conventional
treatment is inadequate for the removal of these newly identified emerging
contaminants, including PFAS compounds, like GenX and Nafion byproducts;
advanced water treatment methods will be required to remove these PFAS
compounds.
o Brunswick County, assisted by CDM Smith, operated a reverse osmosis
pilot unit for 489 days. Based on the knowledge gained and the evaluation
of the alternative treatment methods, GAC and ion exchange, RO
treatment provides the greatest removal of target contaminants and is the
only recommended option for the Northwest Water Treatment Plant
expansion. RO is recommended for the following reasons.
o RO is the most robust technology for protecting against PFAS
contaminants. RO is the most reliable technology for protecting public
health. RO-treated water quality does not rely on frequent media
changeout to protect from spills and contaminants in the Cape Fear River,
of which there have been two in the past two years. Approximately 450
square miles of Brunswick County will no longer be exposed to PFAS
contamination through drinking water, thanks to the addition of RO; 26
square miles of shellfish beds will be better protected from PFAS
Page 47 of 54

exposure thanks to RO-treated drinking water, when it comes to
Brunswick County.
o All wastewater treatment plants in Brunswick County will no longer
receive PFAS-laden wastewater, thanks to RO-treated drinking water. RO
is the best technology for the removal of PFAS. RO does not differentiate
between short -chain and long -chain PFAS compounds, as other
technologies may. RO has the lowest net -present worth cost for removing
90% or more of the targeted contaminants. RO-treated water quality will
not vary as much with influent concentrations as do other technologies.
o Based on these facts and Brunswick County's request for an NPDES
permit to allow the discharge of RO reject water back to where it came
from, the Cape Fear River, I urge you to approve an NPDES permit with
the proper limits that are protective of the environment, and allow for the
efficient operation of a reverse osmosis water treatment facility here in
Brunswick County.
• John Nichols (Director, Brunswick County Public Utilities): I'm the Brunswick
County Public Utilities director and I am a lifelong resident of Brunswick County.
I'm also a water customer, a regular user and a commercial fisherman. I'd like to
thank DEQ staff for being here and I know that many of you have worked very
hard on this permit - on the draft permit. I look forward to working with you
further on it.
o I'm going to give some history. We began the expansion of the Northwest
Water Treatment Plant project back in 2009 - first phase of a three-phase
project. We completed the second phase in 2016, and we're prepared to
start on the third phase, which would expand our capacity in 2017, and
that's when we found out about GenX and PFAS in the water. And so
once we saw that, we had to delay that project in order to look at the
treatment methodologies that we would implement in phase three.
o So, we immediately started working on that. We had CDM Smith on board
in late 2017, and one of the first things that we asked them to do was to go
to DEQ and talk about this NPDES permit because we knew it would be a
very key critical part of work. So, we started those discussions in February
2018. We submitted our formal application in November of 2018. So just
over a year ago. We understood that process would take - the typical
process would take about six months. It has taken much longer than that,
and so what that has created is a situation where we could not bid the
project when we expected to.
o We had a bid date of December 13th, and we had to move that out to
March 5th. And so we need to do this project for two key reasons. One is
for capacity. This past summer, Brunswick County was over 95% of its
water treatment capacity while we were under conservation measures. So
we need more treated water capacity. But the second and probably more
important reason is due to the contaminants, GenX in the river. And so the
residents of Brunswick County need additional water. We need it for the
growth. But the residents and future residents deserve to have clean, safe,
treated water.
o And so we ask that you make this permit a priority. We beseech you.
Please, go back, do what's needed, make whatever revisions are needed to
Page 48 of 54

this permit, and move it forward as quickly as possible, so that we can
move forward with our construction project.
Section 15. NPDES Implementation of Instream Dissolved Metals Standards —
Freshwater 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, metal 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 Quality Standards/Aquatic Life Protection
Parameter
Acute FW, µg/l
(Dissolved)
Chronic FW,
µg/l
(Dissolved)
Acute SW, µg/l
(Dissolved)
Chronic SW,
µg/l
(Dissolved)
Arsenic
340
150
69
36
Beryllium
65
6.5
---
---
Cadmium
Calculation
Calculation
40
8.8
Chromium III
Calculation
Calculation
---
---
Chromium VI
16
11
1100
50
Copper
Calculation
Calculation
4.8
3.1
Lead
Calculation
Calculation
210
8.1
Nickel
Calculation
Calculation
74
8.2
Silver
Calculation
0.06
1.9
0.1
Zinc
Calculation
Calculation
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/1 for human health protection; cyanide at 5 µg/L and fluoride at 1.8 mg/L for
aquatic life protection).
Page 49 of 54

Table 2. Dissolved Freshwater Standards for Hardness -Dependent Metals
The Water Effects Ratio (WER) is equal to one unless determined otherwise under 15A
NCAC 02B .0211 Sub ara rah 11 d
Metal
NC Dissolved Standard, /l
Cadmium, Acute
WER*{1.136672-[ln hardness](0.041838){ e^{0.9151 [ln hardness]-
3.1485}
Cadmium, Acute Trout
waters
WER*{1.136672-[lnhardness](0.041838){ e^{0.9151[lnhardness]-
3.62361
Cadmium, Chronic
WER*{1.101672-[ln hardness](0.041838){ e^{0.7998[ln hardness]-
4.4451 {
Chromium III, Acute
WER*0.316 e^{0.8190[ln hardness]+3.7256{
Chromium III, Chronic
WER*0.860 e"{0.8190[ln hardness]+0.6848{
Copper, Acute
WER*0.960 e^{0.9422[ln hardness]-1.700{
Copper, Chronic
WER*0.960 e^{0.8545[ln hardness]-1.702{
Lead, Acute
WER*{1.46203-[ln hardness](0.145712)) • ell {1.273[ln hardness] -
1.460}
Lead, Chronic
WER*{1.46203-[ln hardness](0.145712)} • e^{1.273[ln hardness]-
4.705 }
Nickel, Acute
WER*0.998 eA f 0.8460[ln hardness]+2.255{
Nickel, Chronic
WER*0.997 e^{0.8460[ln hardness]+0.0584{
Silver, Acute
WER*0.85 • e^{1.72[ln hardness]-6.59{
Silver, Chronic
Not applicable
Zinc, Acute
WER*0.978 e^{0.8473[ln hardness]+0.884{
Zinc, Chronic
WER*0.986 e^{0.8473[ln hardness]+0.884{
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 and hardness -dependent standards requires
additional consideration in order to establish the numeric standard for each metal of
concern of each individual discharge.
The hardness -based standards require some knowledge of the effluent and instream
(upstream) hardness and so must be calculated case -by -case for each discharge.
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 default translator values
developed for each metal (more on that below), but it is also possible to consider case -
specific translators developed in accordance with established methodology.
Page 50 of 54

Section 16. RPA Permitting Guidance/WOBELs for Hardness -Dependent Metals —
Freshwater:
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 standards and the critical low -flow values for the
receiving stream.
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 on the Freshwater hardness -dependent metals the Permit
Writer compiles the following information:
• Critical low flow of the receiving stream, 7Q 10 (the spreadsheet
automatically calculates the 1 Q 10 using the formula 1 Q 10 = 0.843
(S7Q I0, CfS) 0.993
• Effluent hardness and upstream hardness, site -specific data is preferred
• Permitted flow
• Receiving stream classification
2. In order to establish the numeric standard for each hardness -dependent metal of
concern and for each individual discharge, the Permit Writer must first determine
what effluent and instream (upstream) hardness values to use in the equations.
The permit writer reviews DMR's, Effluent Pollutant Scans, and Toxicity Test
results for any hardness data and contacts the Permittee to see if any additional
data is available for instream hardness values, upstream of the discharge.
If no hardness data is available, the permit writer may choose to do an initial
evaluation using a default hardness of 25 mg/L (CaCO3 or (Ca + Mg)). Minimum
and maximum limits on the hardness value used for water quality calculations are
25 mg/L and 400 mg/L, respectively.
If the use of a default hardness value results in a hardness -dependent metal
showing reasonable potential, the permit writer contacts the Permittee and
requests 5 site -specific effluent and upstream hardness samples over a period of
one week. The RPA is rerun using the new data.
The overall hardness value used in the water quality calculations is calculated as
follows:
Combined Hardness (chronic)
_ (Permitted Flow, cfs *Avg. Effluent Hardness, mg/L)xs7Q10, cfs *Avg. Upstream Hardness, m./g_L)
(Permitted Flow, cfs + s7Q 10, cfs)
Page 51 of 54

The Combined Hardness for acute is the same but the calculation uses the IQ 10
flow.
3. The permit writer converts the numeric standard for each metal of concern to a
total recoverable metal, using the EPA Default Partition Coefficients (DPCs) or
site -specific translators, if any have been developed using federally approved
methodology.
EPA default partition coefficients or the "Fraction Dissolved" converts the
value for dissolved metal at laboratory conditions to total recoverable metal
at in -stream ambient conditions. This factor is calculated using the linear
partition coefficients found in The Metals Translator: Guidance for
Calculating a Total Recoverable Permit Limit from a Dissolved Criterion
(EPA 823-B-96-007, June 1996) and the equation:
Cdiss = 1
Ctotal 1 + { [Kpo] [ss(1+a)] [10-6] }
Where:
ss = in -stream suspended solids concentration [mg/1], minimum of 10 mg/L
used, and
Kpo and a = constants that express the equilibrium relationship between
dissolved and adsorbed forms of metals. A list of constants used for each
hardness -dependent metal can also be found in the RPA program under a
4. The numeric standard for each metal of concern is divided by the default partition
coefficient (or site -specific translator) to obtain a Total Recoverable Metal at
ambient conditions.
In some cases, where an EPA default partition coefficient translator does not exist
(ie. silver), the dissolved numeric standard for each metal of concern is divided by
the EPA conversion factor to obtain a Total Recoverable Metal at ambient
conditions. This method presumes that the metal is dissolved to the same extent as
it was during EPA's criteria development for metals. For more information on
conversion factors see the June, 1996 EPA Translator Guidance Document.
The RPA spreadsheet uses a mass balance equation to determine the total
allowable concentration (permit limits) for each pollutant using the following
equation:
Ca = (s7Q10 + Qw)(Cwgs)(s7Q10) (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)
Cb = background concentration: assume zero for all toxicants except NH3*
(µg/L or mg/L)
Page 52 of 54

Qw = permitted effluent flow (cfs, match s7Q 10)
s7Q10 = summer low flow used to protect aquatic life from chronic toxicity
and human health through the consumption of water, fish, and
shellfish from noncarcinogens (cfs)
* Discussions are on -going with EPA on how best to address background
concentrations
Flows other than s7Q10 may be incorporated as applicable:
IQ 10 = used in the equation to protect aquatic life from acute toxicity
QA = used in the equation to protect human health through the
consumption of water, fish, and shellfish from carcinogens
30Q2 = used in the equation to protect aesthetic quality
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.
7. 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.
The Total Chromium NC WQS was removed and replaced with trivalent
chromium and hexavalent chromium Water Quality Standards. 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 III or VI. In these
cases, the projected maximum concentration (95th %) for total chromium will be
compared against water quality standards for chromium III and chromium VI.
9. Effluent hardness sampling and instream hardness sampling, upstream of the
discharge, are inserted into all permits with facilities monitoring for hardness -
dependent metals to ensure the accuracy of the permit limits and to build a more
robust hardness dataset.
Page 53 of 54

10. Hardness and flow values used in the Reasonable Potential Analysis for Outfall
001 for this permit included:
Parameter
Value
Comments Data Source
Average Effluent Hardness
25 mg/L
DMRs from April 2018 to
(mg/L)
August 2019
[Total as, CaCO3 or Ca+M
Average Upstream Hardness
28 mg/L
DMRs from May 2018 to
(mg/L)
August 2019
Total as, CaCO3 or Ca+M
7Q10 summer cfs
0.07 cfs
Value pulled from BIMS
1 Q 10 (cfs)
0.06 cfs
Value pulled from RPA
Permitted Flow (MGD)
N/A
WTP's do not have permitted
flow included in permits
11. Hardness and flow values used in the Reasonable Potential Analysis for Outfall
002 for this permit included:
Parameter
Value
Comments (Data Source)
Average Effluent Hardness
221.2 mg/L
Pilot study conducted at 85%
(mg/L)
efficiency and 92% efficiency;
[Total as, CaCO3 or (Ca+Mg)]
Value is average of data
provided for both efficiencies
combined
Average Upstream Hardness
25
Upstream data not provided as
(mg/L)
part of pilot study; Standard
Total as, CaCO3 or Ca+M
minimum used
7Q10 summer (cfs)
15.5 cfs
7Q10 for noncarcinogenic
parameters
69.75 cfs
7Q10 for carcinogenic
parameters
Based on dilution model
submitted with application
1 Q 10 (cfs)
12.82 cfs
1 Q 10 for noncarcinogenic
parameters
57.08 cfs
IQ 10 for carcinogenic
parameters
Based on dilution model
submitted with application
Permitted Flow (MGD)
N/A
WTP's do not have permitted
flow included in permits
Page 54 of 54