NC0090069_Draft Permit_20220404

ROY COOPER
Governor
ELISABETH S. BISER
Secretary
RICHARD E. ROGERS
Director
NORTH CAROLINA
Erw ronmertlro! Qrta'UUy
April 5, 2022
Josh Glover Owner, LLC
Attn: Josh Glover, VP
521 East Morehead Street, Suite 350
Charlotte North Carolina 28202
Subject: DRAFT Review of NPDES Permit
NC0090069, WPCS Grade PCNC
Elon LoSo Dewatering GW-REM
ECS Project No. 49:14242
Mecklenburg County, NC
Mr. Glover:
The Division of Water Resources (DWR or the Division) received on November 12, 2021, your
application for a permit to discharge to surface waters of the State. We hereby provide you with the
subject permit draft.
Please review this draft carefully to ensure your understanding of its limits and monitoring conditions.
Concurrent with this transmission, the Division will solicit public comment on this draft by publishing a
notice in newspapers having circulation in the general Mecklenburg County area, as required by the
NPDES Program. Please submit your written comments (if any), attention NCDEQ / DWR / NPDES
[[e-mail]] no later than May 9, 2022 (approximately 30 days after receiving this
document). We welcome your written comments, but they are not mandatory.
Scope of Work:
The Division understands that Josh Glover Owner, LLC [Glover] proposes to upgrade habitable
structures located at 301 Verbena Street, Macie Street [unnumbered], and Yeoman Street [300 301, 304,
308, 310 and 321] in Charlotte. We further understand that you intend to:
1. advance infrastructure excavations below the local groundwater surface
2. install temporary dewatering system to support local excavations and installations, and
3. install permanent dewatering systems for structures advanced below the groundwater table.
Treatment System Exceptions:
Please note that final effluent filters proposed to align in parallel are not acceptable. DWR prefers carbon
filters intended to polish final effluent should be arranged in series to allow monitoring and recording of
filter breakthrough prior to discharge to the environment. It follows that a sample port is required after
the upstream filter (See Supplement to Permit Cover Sheet). Treatment logs are to be kept onsite
available for DWR inspection.
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617 -- 919.707.9000

Josh Glover
Elon LoSo Dewatering
Draft Discharge Permit Review
Page 2 of 2
Permitting Strategies:
Considering Glover's application, DWR has established a list of Parameters of Concern (POCs) for
initial sampling but has also provided for future review of monitoring requirements, as warranted [see
permit section A. (1.)]. Glover may petition DWR to reevaluate monitoring, as future data may warrant.
Monthly Report Submittals:
Federal regulations require electronic submittal of all program reports and Monthly Discharge
Monitoring Reports (DMRs). Please note that Glover must successfully register for the Electronic
Discharge Monitoring Report (eDMR) program. I addition, you must also fill out and submit to DWQ
an Electronic Signature Agreement. By so doing, you forgo the need to submit DMR hardcopy as
back-up to the eDMR [see Permit Condition A. (3.)].
Please note that the receiving stream, Erwin Creek is listed as impaired for Total Lead (Pb) on the
North Carolina 2018 303(d) Impaired Waters List. Addressing impaired waters is a high priority with
the Division, and instream data will continue to be evaluated. If there is noncompliance with permitted
effluent limits and stream impairment can be attributed to your facility, then mitigative measures may
be required.
Following the mandatory 45-day Public Comment period, the Division will review all pertinent
comments, if any, and take appropriate action prior to issuing an NPDES permit final. If you have
questions, please email the undersigned at [[e-mail]].
In support of mandated emergency response to Covid 19, much of NC state government currently
functions remotely, therefore correspondence via email is preferred.
Jo . Corpo on, P.G
D. Q / DW/ NPDES Permitting
Enclosure: NPDES Permit NC0090069 (renewal draft)
ec: DWR/NPDES, Program Files / Laserfiche
DWR/MRO/SWPS, Cory Basinger, Supervisor
DWR/OCU, Maureen Kinney
ECS Consultant, Joseph P. Nester, [[e-mail]]
ECS, Scott M. Werley [swerleyEecslimited.com]
Greystar, Kory Jeter, ORC [[e-mail]]

NPDES Permit NC0090069
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
(NPDES)
In compliance with the provisions of North Carolina General Statute 143-215.1, other lawful standards
and regulations promulgated and adopted by the North Carolina Environmental Management
Commission, and the Federal Water Pollution Control Act, as amended,
Elon LoSo Owner LLC
is hereby authorized to discharge treated wastewaters from excavation
and permanent structures advanced below the groundwater table described as
ECS Project No. 14242, NC Brownfields Program
301 Verbena Street, Macie Street [unnumbered], and
Yeoman Street [300, 301, 304, 308, 310 and 321], Charlotte
Mecklenburg County
to a receiving waterbody designated as an unnamed tributary (UT) to Erwin Creek within the Catawba
River Basin, in accordance with effluent limitations, monitoring requirements, and other conditions set
forth in Parts I, II, III, and IV hereof.
The permit shall become effective 2022
This permit and the authorization to discharge shall expire at midnight on June 30, 2027.
Signed this day 2022.
for Richard E. Rogers, Jr., Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 8

NPDES Permit NC0090069
SUPPLEMENT TO PERMIT COVER SHEET
[new NPDES Permit — no previous permits]
Elon LoSo Owner LLC
is hereby authorized to:
1. construct and operate a groundwater remediation system in support of excavation and foundation
dewatering of various structures located at 301 Verbena Street, Macie Street [unnumbered], and
Yeoman Street [300 301, 304, 308, 310 and 321], Charlotte, operating at a flow rate not to
exceed 0.050 MGD; this proposed treatment system consisting of, but not limited to
• one (1) 1,100-gallon settling/ surge tank
• two (2) each particulate filter trains [aligned in parallel]
• four (4) each granular activated carbon (GAC) vessels [aligned in series — two
per train] with sample ports between to document contaminant breakthrough
prior to release to the environment].
• effluent totalizing flow meter.
2. for permanent dewatering of structure(s), in compliance with this permit, upon completion of
excavation(s), the Permittee will submit to the Division details of alterations to treatment systems
(if any), then
3. continue to discharge from said treatment works via Outfa11001 designated to storm -sewer inlet
upstream of Storm Structure [IRW182-7777], an unnamed tributary to (UT) to Erwin Creek
[Stream Index 11-137-1], a waterbody currently classified C waters within subbasin 03-08-34
[HUC: 030501030101] of the Catawba River Basin.
Page 2 of 8

NPDES Permit NC0090069
PART I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.] WWTP Grade PC Physical/Chemical [15A NCAC 08G .0302]
During the period beginning on the effective date of this permit and lasting until completion, the
Permittee is authorized to discharge via Outfall 001 [stormsewer inlet]. Such discharges shall be limited,
monitored 1 and reported 2 by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
[BIMS Parameter Code]
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location
Flow (MGD)
50050
0.050
0.050
Episodic
Recording
Effluent
pH (standard units)
00400
Not < 6.0 or > 9.0 s. u.
2/Monthly
Grab
Effluent
Total Lead *
0.54 ug/L
13.88 ug/L
2/Monthly
Grab
Effluent
Benzene
34030
51 µg/L
51 µg/L
2/Monthly
Grab
Effluent
Tetrachlorethylene (PCE)
78389
3.3 µg/L
3.3 µg/L
2/Monthly
Grab
Effluent
Toluene
34010
11 µg/L
11 µg/L
2/Monthly
Grab
Effluent
Ethylbenzene
34371
97 µg/L
97 µg/L
2/Monthly
Grab
Effluent
Total Xylenes
81551
670 µg/L
670 µg/L
2/Monthly
Grab
Effluent
Tetrachloroethylene (PCE)
3.3 µg/L
3.3 µg/L
2/Monthly
Grab
Effluent
Chloroform (ug/L)*
32160
2,000 ug/L
2,000 ug/L
2/Monthly
Grab
Effluent
Total Hardness (mg/L)
[CaCO3 or Ca + Mg]
00900
Monitor and Report
Monthly
Grab
Effluent
1,2 dichloroethane (ug/L) **
32103
Monitor and Report
Monthly
Grab
Effluent
1,1 dichloroethane (ug/L)
34496
Monitor and Report
Monthly
Grab
Effluent
1,2-trans-dichloroethylene (ug/L)
Monitor and Report
Monthly
Grab
Effluent
Whole Effluent Toxicity (WET) 3
TAA6C
Monitor and Report
Monthly
Grab
Effluent
Oil and Grease (mg/L)
[EPA Method 1664 SGT-HEM]
00556
Quarterly
Grab
Effluent
Total PAHs 4 (µg/L)
(EPA Method 8270D)
C0456
Quarterly
Grab
Effluent
Polychlorinated biphenyls (PCBs) 4
(µg/L) (EPA Method 8280A)
39516
Quarterly
Grab
Effluent
Organics, Total Purgeable (VOCs) 4
(µg/L), EPA Method 624
76029
Quarterly
Grab
Effluent
Base Neutrals & Acids Semi-VOCs 4
(µg/L), EPA Method 625
76028
Quarterly
Grab
Effluent
* EPA Recommended
**Total Hardness dependent
Page 3 of 8

NPDES Permit NC0090069
Footnotes (for page.3):
1. Available onsite for DWR inspection, the Permittee shall maintain all internal sampling logs and
laboratory analyses conducted to verify internal system treatment -component contaminant breakthrough.
2. Beginning on the effective date of this permit, the Permittee shall submit monthly Discharge
Monitoring Reports (DMRs) electronically using the Division's eDMR application system [see
Condition A. (3.)].
3. Whole Effluent Toxicity (WET): Acute, Monitor Only; Monthly (Pimephales promelas) 48-hour
static test. [See Section A. (2.)].
4. Sampling and analyses of this test method shall be conducted during the first month of each
calendar quarter. If detected, parameters shall be entered in the eDMR "Comments" Section, to
include its reported concentration. If detected, report as "1" [Yes (Y) =1], and if not detected,
report "0" [NO (N) = 0]. Laboratory reports shall be kept on file available for DWR inspection in
accordance with records retention requirements, Part II, Section D.
5. Glover may petition DWR to reevaluate monitoring, as future data may warrant. This stipulation
Conditions: Permit limits apply at end -of -pipe [NCAC 02B. 0211(21]. Compliance problems shall be
addressed through Best Management Practices [NCAC 02B. 0202].
A. (2.) ACUTE TOXICITY MONTHLY - MONITOR ONLY
[15A NCAC 02B .0200 et seq.]
The permittee shall conduct acute toxicity tests on a monthly basis using protocols defined as definitive
in EPA Document EPA-821-R-02-012 entitled "Methods for Measuring the Acute Toxicity of Effluents
and Receiving Waters to Freshwater and Marine Organisms." The monitoring shall be performed as a
Fathead Minnow (Pimephales promelas) 48-hour static test. Effluent samples for self -monitoring
purposes must be obtained during representative effluent discharge and shall be performed at the
NPDES permitted final effluent discharge below all waste treatment processes.
The parameter code for Pimephales promelas is TAA6C. All toxicity testing results required as part of
this permit condition will be entered electronically using the Division's eDMR system for the month in
which it was performed, using the appropriate parameter code. Additionally, DWR Form AT-1
(original) is to be sent to the following address:
North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, NC 27699-1621
Or, results can be sent to the email, [e-mail].
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30 days after th
end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/physical measurements and all
concentration/response data, and be certified by laboratory supervisor and ORC or approved designate
signature.
Page 4 of 8

NPDES Permit NC0090069
Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for
disinfection of the waste stream.
Should there be no discharge of flow from the facility during any month, the permittee will complete the
information located at the top of the aquatic toxicity (AT) test form indicating the facility name, permit
number, pipe number, county, and the month/year of the report with the notation of "No Flow" in the
comment area of the form. The report shall be submitted to the Water Sciences Section at the address
cited above.
Should any test data from either these monitoring requirements or tests performed by the North Carolina
Division of Water Resources indicate potential impacts to the receiving stream, this permit may be re-
opened and modified to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control
organism survival and appropriate environmental controls, shall constitute an invalid test and will
require immediate follow-up testing to be completed no later than the last day of the month following
the month of the initial monitoring.
A. (3.) ELECTRONIC REPORTING OF MONITORING REPORTS
[NCGS 143-215.1 (b)]
Federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and program
reports. The final NPDES Electronic Reporting Rule was adopted and became effective on December
21, 2015.
NOTE: This special condition supplements or supersedes the following sections within Part II of this
permit (Standard Conditions for NPDES Permits):
• Section B. (11.) Signatory Requirements
• Section D. (2.) Reporting
• Section D. (6.) Records Retention
• Section E. (5.) Monitoring Reports
1. Reporting Requirements [Supersedes Section D. (2.) and Section E. (5.) (a)1
The permittee shall report discharge monitoring data electronically using the NC DWR's Electronic
Discharge Monitoring Report (eDMR) internet application.
Monitoring results obtained during the previous month(s) shall be summarized for each month and
submitted electronically using eDMR. The eDMR system allows permitted facilities to enter monitoring
data and submit DMRs electronically using the internet. The eDMR system may be accessed at:
https://deq.nc.gov/about/divisions/water-resources/edmr.
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility
being physically located in an area where less than 10 percent of the households have broadband access,
then a temporary waiver from the NPDES electronic reporting requirements may be granted and
discharge monitoring data may be submitted on paper DMR forms (MR 1, 1.1, 2, 3) or alternative forms
approved by the Director. Duplicate signed copies shall be submitted to the following address:
NC DEQ / Division of Water Resources / Water Quality Permitting Section
Page 5 of 8

NPDES Permit NC0090069
ATTENTION: Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
See "How to Request a Waiver from Electronic Reporting" section below
Regardless of the submission method, the first DMR is due on the last day of the month following the
issuance of the permit or in the case of a new facility, on the last day of the month following the
commencement of discharge.
Starting on December 21, 2025, the permittee must electronically report the following compliance
monitoring data and reports, when applicable:
• Sewer Overflow/Bypass Event Reports;
• Pretreatment Program Annual Reports; and
• Clean Water Act (CWA) Section 316(b) Annual Reports.
The permittee may seek an electronic reporting waiver from the Division (see "How to Request a
Waiver from Electronic Reporting" section below).
Page 6 of 8

NPDES Permit NC0090069
2. Electronic Submissions
In accordance with 40 CFR 122.41(1)(9), the permittee must identify the initial recipient at the time of
each electronic submission. The permittee should use the EPA's website resources to identify the initial
recipient for the electronic submission.
Initial recipient of electronic NPDES information from NPDES-regulated facilities means the entity
(EPA or the state authorized by EPA to implement the NPDES program) that is the designated entity for
receiving electronic NPDES data [see 40 CFR 127.2(b)].
EPA plans to establish a website that will also link to the appropriate electronic reporting tool for each
type of electronic submission and for each state. Instructions on how to access and use the appropriate
electronic reporting tool will be available as well. Information on EPA's NPDES Electronic Reporting
Rule is found at: https://www.federalregister.gov/documents/2015/10/22/2015-24954/national-pollutant-
discharge-elimination-system-npdes-electronic-reporting-rule
Electronic submissions must start by the dates listed in the "Reporting Requirements" section above.
3. How to Request a Waiver from Electronic Reporting
The permittee may seek a temporary electronic reporting waiver from the Division. To obtain an
electronic reporting waiver, a permittee must first submit an electronic reporting waiver request to the
Division. Requests for temporary electronic reporting waivers must be submitted in writing to the
Division for written approval at least sixty (60) days prior to the date the facility would be required
under this permit to begin submitting monitoring data and reports. The duration of a temporary waiver
shall not exceed 5 years and shall thereupon expire. At such time, monitoring data and reports shall be
submitted electronically to the Division unless the permittee re -applies for and is granted a new
temporary electronic reporting waiver by the Division. Approved electronic reporting waivers are not
transferrable. Only permittees with an approved reporting waiver request may submit monitoring data
and reports on paper to the Division for the period that the approved reporting waiver request is
effective.
Information on eDMR and the application for a temporary electronic reporting waiver are found on the
following web page:
http://deq.nc.gov/about/divisions/water-resources/edmr
4. Signatory Requirements [Supplements Section B. (11.) (b) & Supersedes Section B. (11.) (d)1
All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II,
Section B. (11.)(a) or by a duly authorized representative of that person as described in Part II, Section
B. (11.)(b). A person, and not a position, must be delegated signatory authority for eDMR reporting
purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user account
and login credentials to access the eDMR system. For more information on North Carolina's eDMR
system, registering for eDMR and obtaining an eDMR user account, please visit the following web
page: http://deq.nc.gov/about/divisions/water-resources/edmr
Page 7 of 8

NPDES Permit NC0090069
Certification. Any person submitting an electronic DMR using the state's eDMR system shall make the
following certification [40 CFR 122.22]. NO OTHER STATEMENTS OF CERTIFICATION WILL
BE ACCEPTED:
"I certify, under penalty of law, that this document and all attachments were prepared under my
direction or supervision in accordance with a system designed to assure that qualified personnel
properly gather and evaluate the information submitted. Based on my inquiry of the person or persons
who manage the system, or those persons directly responsible for gathering the information, the
information submitted is, to the best of my knowledge and belief true, accurate, and complete. I am
aware that there are significant penalties for submitting false information, including the possibility of
fines and imprisonment for knowing violations."
Records Retention [Supplements Section D. (6.)1
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR submissions.
These records or copies shall be maintained for a period of at least 3 years from the date of the report.
This period may be extended by request of the Director at any time [40 CFR 122.41].
Page 8 of 8

DEQ / DWR / NPDES
EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL
NPDES Permit NC0090069
Joe R. Corporon, P. G., Compliance & Expedited Permitting Unit
04Apr2022
Table 1 - Facility Information
Applicant/Facility
Name
Elon LoSo Owner LLC
Operations:
Infrastructure Excavation and Permanent Building Dewatering
Applicant Address:
521 East Morehead Street, Suite 350, Charlotte NC 28202
Site Contacts/ '
Consultants:
Kory Jeter, ORC [[e-mail]]
Joseph P. Nestor [[e-mail]], 704-280-7422
Facility Addresses:
Include 301 Verbena Street, Macie Street [unnumbered], and
Yeoman Street [300 301, 304, 308, 310 and 321], Charlotte
Permitted Flow
(MGD)
0.050 MGD
Waste Character:
100% industrial, privately owned, <1.0 MGD
Facility Class:
PC -Physical / Chemical
County:
Mecklenburg
Permit Status:
NEW
Regional Office:
MRO
Stream Characteristics mi
Receiving Stream:
UT to Irwin Creek
Stream
Classification:
C
Stream Segment:
11-137-1
Drainage basin:
Catawba
Summer 7Q10 (cfs):
0
Subbasin [HUC]:
03-08-32 [030501030101]
Winter 7Q10 (cfs):
0
Use Support:
No. Impaired for Pb
30Q2 (cfs):
0
303(d) Listed:
IRC = 5 since 2008
Average Flow (cfs):
0
State Grid:
G15NE
IWC (%):
100%
(zero -flow conditions)
2+ miles to creek
USGS Topo
Quad:
Charlotte E, NC
Draft Peer Reviewer:
Emily Richards (NPDES)
Facility Summary:
The Division understands that Josh Glover Owner, LLC [Glover] proposes to upgrade habitable
structures located at 301 Verbena Street, Macie Street [unnumbered], and Yeoman Street [300 301,
304, 308, 310 and 321] in Charlotte. The scope of work proposes to:
1. advance infrastructure excavations below the local groundwater surface
2. install temporary dewatering system to support local excavations and installations, and
3. install permanent dewatering systems for structures advanced below the groundwater table.
Proposed Treatment System and Exceptions: The Permittee proposes to align final effluent
filters in parallel. This is not acceptable. Granular activated carbon (GAC) vessels intended to
polish final effluent shall be arranged in series with sample port between to allow monitoring and
recording of filter breakthrough prior to discharge to the environment. It follows that a sample port
Fact Sheet Apr2022
NPDES Permit NC0090069
Page 1

is required after the upstream filter (See Supplement to Permit Cover Sheet). Treatment logs and
internal sampling shall be kept available for DWR inspection.
• one (1) 1,100-gallon settling/ surge tank
• two (2) each particulate filter trains [aligned in parallel]
• four (4) each granular activated carbon (GAC) vessels [aligned in series —
two per train] with sample ports between to document contaminant
breakthrough prior to release to the environment].
• effluent totalizing flow meter.
Receiving Stream and Outfall 001: The receiving stream Irwin Creek [segment 11-137-1] is
currently listed as impaired for Lead [2018 Integrated Report 305(b)]. Storm sewer and
dewatering Outfall 001 [See site location map] discharge to as an unnamed tributary (UT)
flowing generally north to Irwin Creek under zero -flow receiving -stream conditions [7Q10/30Q2
= 0.0 cfs]. Effluent limitations therefore assume an instream waste concentration (IWC) of
100%, as required of all storm sewer discharges.
Permitting Strategies - Rationale for Renewal Limits: Considering Glover's application, DWR
has established a list of Parameters of Concern (POCs) for initial sampling but has also provided
for future review of monitoring requirements. Glover may petition DWR to reevaluate monitoring,
as future data may warrant [see permit section A. (1.)].
Contaminates "believed present" require monitoring. Those with established Surface Water
Quality Standards, either NC or EPA, have been assigned permit limits equal to those Standards,
whichever the more stringent. Additional contaminants are assigned "Monitor and Report" but are
not permit limited [see permit section A. (1.)]. Quarterly Monitoring is assigned to several
multiple -parameter scans [EPA 624 and 625, PAHs and PCBs] to evaluate as a spot check for
unknowns previously undetected.
Public Notice - New Discharge: The following is submitted for Public Notice:
"Josh Glover Owner, LLC, 521 E. Morehead St., Charlotte, applied for permit NC0090069 to
discharge treated wastewater to an unnamed tributary to Erwin Creek, Catawba River Basin.
Water -quality limited parameters from GW dewatering include: BTEX, Chloroform, 1,1
dichloroethane, 1,2 dichloroethane, tetrachloroethylene (PCE), and 1,2 trans-dichloroethylene.
This discharge may affect future wasteload allocations to the receiving stream."
PROPOSED SCHEDULE FOR PERMIT ISSUANCE:
Public Notice (estimated):
Issuance (estimated):
Effective Date (estimated):
April 5, 2022
May 10, 2022
July 1, 2022
Fact Sheet Apr2022
NPDES Permit NC0090069
Page 2

NPDES DIVISION CONTACT
If you have questions regarding any of the above or the attached permit, please contact Joe R.
Corporon, P.G., email preferred [[e-mail]].
Joe R. C rporon,
DEQ / R / NPDES Permitting
NPDES Implementation of Instream Dissolved Metals Standards — Freshwater
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 Notes:
1. FW= Freshwater, SW= Saltwater
2. Lalculation = 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 2B.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).
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 Subparagraph (11)(d)
Metal
NC Dissolved Standard, µg/1
Cadmium, Acute
WER*{1.136672-[ln hardness](0.041838)} • e^{0.9151 [ln hardness]-
3.1485}
Cadmium, Acute
waters
Trout
WER* { 1.136672-[ln hardness](0.041838)} • e^{0.9151 [ln hardness] -
3.6236}
Cadmium, Chronic
WER*{1.101672-[ln hardness](0.041838)} • e^{0.7998[In hardness ]-
4.4451 }
Chromium III, Acute
WER*0.316 • e^{0.8190[ln hardness]+3.7256}
Fact Sheet Apr2022
NPDES Permit NC0090069
Page 3

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)} •
1.460}
e^{1.273[In
hardness]-
Lead, Chronic
WER*{1.46203-[ln hardness](0.145712)} •
4.705 }
e^{1.273[In
hardness]-
Nickel, Acute
WER*0.998 • e^{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.
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, 7Q10 (the spreadsheet automatically calculates
the 1Q10 using the formula 1Q10 = 0.843 (s7Q10, cfs) 0.993
Fact Sheet Apr2022
NPDES Permit NC0090069
Page 4

• 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) x (s7Q10, cfs *Avg. Upstream Hardness, mg/L)
(Permitted Flow, cfs + s7Q10, cfs)
The Combined Hardness for acute is the same but the calculation uses the 1 Q 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
Ctotai 1 + { [Kpo] [ss(t+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 sheet labeled DPCs.
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.
Fact Sheet Apr2022
NPDES Permit NC0090069
Page 5

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.
5. 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) (Cwqs) — (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)
Qw = permitted effluent flow (cfs, match s7Q10)
s7Q 10 = 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:
1 Q 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
6. 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.
8. 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.
Fact Sheet Apr2022
NPDES Permit NC0090069
Page 6

10. Hardness and flow values used in the Reasonable Potential Analysis for this permit included:
Parameter
Value
Comments (Data Source)
Average Effluent Hardness (mg/L)
[Total as, CaCO3 or (Ca + Mg)]
No discharge data to date
Average Upstream Hardness (mg/L)
[Total as, CaCO3 or (Ca + Mg)]
No monitoring data to date
7Q10 summer (cfs)
0.0
Storm -sewer discharge IWC = 100%
1Q10 (cfs)
0.0
Storm -sewer discharge IWC = 100%
Permitted Flow (MGD)
0.050
Assumed monthly average.
Fact Sheet Apr2022
NPDES Permit NC0090069
Page 7

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NPDES Permit NC0090069
Mecklenburg County

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Facility Location Map 2
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NPDES Permit NC0090069
Mecklenburg County