NC0036196_Fact Sheet_20240613

Fact Sheet
NPDES Permit No. NCO036196
Permit Writer/Email Contact:Nick Coco,[e-mail]
Date: 5/31/2024
Division/Branch:NC Division of Water Resources/NPDES Municipal Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑ Renewal
❑ Renewal with Expansion
❑ New Discharge
N Modification(Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers,EPA Form 2A or 2D requirements,Engineering Alternatives Analysis,Fee
• For Existing Dischargers (POTW),EPA Form 2A, 3 effluent pollutant scans,4 2nd species WET
tests.
• For Existing Dischargers (Non-POTW),EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
Facility Information
Applicant/Facility Name: City of Newton/Clark Creek Wastewater Treatment Plant(WWTP)
Applicant Address: PO Box 550,Newton,NC 28658
Facility Address: 1407 McKay Road,Newton,NC 28658
Permitted Flow: 5.0 MGD with expanded flow tier 7.5 MGD
Facility Type/Waste: MAJOR Municipal; 97.8%domestic,2.2%industrial*
Facility Class: Grade IV Biological Water Pollution Control System
Treatment Units Influent pump station,mechanical screen,two aerated grit chambers, lime
addition,two primary clarifiers, four aeration basins,three secondary
clarifiers,two dual media filters, dual chlorine contact basins, dechlorination,
two gravity sludge thickeners,two centrifuge sludge thickeners,post aeration,
standby generator
Pretreatment Program(Y/N) Y; LTMP
County: Catawba
Region Mooresville
*Based on permitted flows.
Briefly describe the proposed permitting action and facility background: The City of Newton has applied
for NPDES permit modification on May 20,2024 requesting re-evaluation of existing aluminum limits, as
they are believed to be calculated in error. The only pollutant being addressed with this modification is
aluminum.
As the calculation has been found to be based on an outdated and invalid EPA Nationally Recommended
Water Quality Criterion,the major modification fee has been waived. Please see Water Quality-Based
Effluent Limitations (WQBELs) and Antibacksliding Review for more information.
Page 1 of 4

2. Receiving Waterbody Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s): Outfall 001 —Clark Creek
Stream Segment: 11-129-5-(0.3)b
Stream Classification: C
Drainage Area(mi): 29.3
Summer 7Q10(cfs): 6.0
Winter 7Q10(cfs): 10.0
30Q2 (cfs): -
Average Flow(cfs): 35.0
IWC (%effluent): 56%at 5.0 MGD, 66%at 7.5 MGD
2022 303(d) listed/parameter: Yes—exceeding criteria for Benthos
Subject to TMDL/parameter: Yes- State wide Mercury TMDL implementation.
Subbasin/HUC: 03-08-35/03050102
3. Effluent Data Summary
Effluent data for Outfall 001 is summarized below for the period of September 2019 through February
2024.
Table 1. Effluent Data Summary Outfall 001
Parameter Units Average Max Min
Flow MGD 3.0 10.9 1.3
Aluminum ug/L 78 1140 6
MA-Monthly Average,WA-Weekly Average,DM-Daily Maximum,DA=Daily Average, QA= Quarterly
Average
4. Compliance Summary
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): The facility passed 17 of 17 quarterly chronic toxicity tests as well as 3 of 3 second species
toxicity tests from March 2020 to March 2024.
5. Water Quality-Based Effluent Limitations (WQBELs)
The current permit contains aluminum limits based on an outdated and invalid EPA Nationally
Recommended Water Quality Criteria(NRWQC)for total aluminum is 87 ug/L for waters with a pH
within the range of 6.5 to 9.0 standard units. In 2018,prior to the 2021 permit renewal, EPA provided an
updated NRWQC for aluminum for the protection of aquatic life. This updated NRWQC is calculation-
based and considers site-specific information regarding water chemistry parameters that have the greatest
impact on aluminum's bioavailability(dissolved organic carbon,pH and hardness), and should have been
used when assessing need for effluent aluminum requirements during the 2021 renewal process.
The Division has calculated derived numeric criteria for total aluminum in accordance with 15A NCAC
02B .0208 for the protection of human health. These derived criteria do not consider protection of aquatic
life. The Division's Standards Branch has been informed of the gap in availability of an aquatic life
protection-based derived criterion for aluminum and has informed the NPDES staff that this is in queue
for development. As this process can be lengthy and is not expected to begin shortly, use of the EPA
NRWQC has been deemed appropriate.
Page 2 of 4

As no upstream data are available for dissolved organic carbon(DOC) and higher dissolved organic
carbon reduces bioavailability because Aluminum is bound to DOC,making the aluminum less
bioavailable to aquatic organisms, an evaluation of the criteria could not be sufficiently made.
To provide sufficient inputs for the EPA NRWQC calculation,upstream monitoring for DOC and pH has
been added to the permit at a quarterly frequency. Upstream hardness sampling is currently required at a
quarterly frequency.
Total aluminum limits have been removed from the permit and monitoring has been reduced from
monthly to quarterly. Quarterly monitoring for effluent total aluminum and upstream DOC,pH and
hardness shall be conducted in conjunction with quarterly chronic toxicity testing. The permit may be
reopened to re-evaluate the need for further aluminum actions upon collection of sufficient data.
6. Antibacksliding Review:
Sections 402(o)(2) and 303(d)(4)of the CWA and federal regulations at 40 CFR 122.44(1)prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit,with some exceptions where limitations
may be relaxed(e.g.,based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit(YES/NO):YES
If YES, confirm that antibacksliding provisions are not violated: During the 2021 renewal, an outdated
EPA NRWQC was used for assessment of need for total aluminum limitations.As the EPA revised their
NRWQC in 2018,the outdated value should not have been used. The use of the outdated value is
considered a"technical mistakes or mistaken interpretations of law"and is an exception to the
antibacksliding rule per 40 CFR 122.44(1)(2)(i)(13)(2). The limits in the permit have been removed. To
evaluate total aluminum in accordance with the 2018 EPA NRWQC, quarterly monitoring for upstream
pH and DOC has been added to the permit. Total aluminum monitoring is required in the permit at a
quarterly frequency. Monitoring for upstream hardness,pH and DOC and effluent total aluminum shall be
conducted in conjunction with quarterly chronic toxicity testing.
7.Summary of Proposed Permitting Actions:
Table 2. Current Permit Conditions and Proposed Changes Outfall 001
Parameter Current Permit Proposed Change Basis for Condition/Change
Total @ 5.0 MGD: Both flow tiers: For evaluation of 2018 total aluminum
Aluminum MA 154.3 µg/1 Monitor and report EPA NRWQC. Incorrect value used
DM 154.3 µg/l quarterly—coincide during 2021 renewal, anti-backsliding
Monthly monitoring with toxicity testing exception—technical mistake
@ 7.5 MGD:
MA 131.9 µg/l
DM 131.9 µg/l
Monthly monitoring
Upstream Both flow tiers: Both flow tiers: For evaluation of total aluminum EPA
monitoring Quarterly monitoring for Add quarterly NRWQC
total hardness monitoring for DOC
and pH—coincide
with toxicity testing
MGD—Million gallons per day,MA- Monthly Average,WA—Weekly Average,DM—Daily Max
Page 3 of 4

8. Public Notice Schedule:
Permit to Public Notice: xx/xx/xxxx
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice.Any request for a public hearing shall be submitted to the
Director within the 30 days comment period indicating the interest of the party filing such request and the
reasons why a hearing is warranted.
9. NPDES Division Contact
If you have any questions regarding any of the above information or on the attached permit,please
contact Nick Coco at(919) 707-3609 or via email at [e-mail].
10. Fact Sheet Addendum (if applicable):
Were there any changes made since the Draft Permit was public noticed(Yes/No):NO
If Yes, list changes and their basis below:NA
11. Fact Sheet Attachments (if applicable):
• Request for Modification
• Fact Sheet: Final 2018 Aquatic Life Ambient Water Quality Criteria for Aluminum in
Freshwaters
• Whole Effluent Toxicity Summary
Page 4 of 4

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P.O. Box 550* Newton, N.C. 28658*[phone]
May 20, 2024
Michael Montebello
NPDES Branch Chief
1617 Mail Service Center
Raleigh, NC 27699-1617
Re: NOV's for Aluminum and removal of parameter limits from permit
Mr. Montebello,
The City of Newton is asking that the Aluminum limits that are currently on our Wastewater Permit be
removed because we feel that the limits were calculated in error and removing them wouldn't trigger a
backslide.
We also ask that you waive the Major Modification fee on this as well as modify our permit and remove
the limits on this parameter and allow us to monitor them quarterly.
We acknowledge the NOV's but understand that the monetary fines will be rescinded.
Thank you for your consideration on these issues.
Since ely,
Eric J n s
WWT Superintendent
City of Newton

Office
UnitedASK •nmental ProtectionEPA 00
Agency December 2018
Fact Sheet: Final 2018 Aquatic life Ambient Water
Quality Criteria for Aluminum in Freshwaters
Summary What is Aluminum and How Does It Enter
The EPA has published final updated aquatic life the Water?
ambient water quality criteria recommendations for Aluminum is found in most soils and rocks. It is the
aluminum in freshwater under Section 304(a)(1) of third most abundant element and the most common
the Clean Water Act to reflect the latest scientific metal in the earth's crust. Aluminum can enter the
knowledge. There are not enough data to support water via natural processes, like weathering of rocks.
the development of estuarine/marine aluminum Aluminum is also released to water by mining,
criteria at this time. Aluminum can inhibit an aquatic industrial processes using aluminum, and in waste
organism's ability to regulate salt concentrations and water and drinking water treated with alum, an
clog fish gills, potentially resulting in death or aluminum compound.
affecting growth and reproduction.
States and authorized tribes can adopt these criteria How Does Aluminum Affect Aquatic Life?
into their water quality standards or can adopt other Aluminum is considered a non-essential metal
aluminum criteria that is scientifically defensible because fish and other aquatic life do not need it to
based on local or site-specific conditions. These final function. Elevated levels of aluminum can affect
criteria are not a regulation, nor do they impose a some species' ability to regulate ions, like salts, and
legally-binding requirement. These criteria provide inhibit respiratory functions, like breathing.
information for states to develop science-based Aluminum can accumulate on the surface of a fish's
standards that reflect site-specific factors and are gill, leading to respiratory dysfunction, and possibly
protective against the effects of aluminum on death. Aquatic plants are generally less sensitive to
aquatic life. aluminum than fish and other aquatic life.
Background What is a Water Chemistry Parameter and
The EPA first published criteria for aluminum in Why is it Important?
1988.The updated aluminum criteria better reflect Bioavailability is the measure of whether a substance
the latest science. Studies have shown that three in the environment is available to affect living
water chemistry parameters— pH, total hardness, organisms, like fish.The bioavailability of aluminum
and dissolved organic carbon (DOC)—can affect the is dependent on the chemistry of the water. The
toxicity of aluminum by affecting the bioavailability more bioavailable the aluminum is, the more likely it
of aluminum in the water to aquatic species. Unlike is to cause a toxic effect. The water chemistry
the fixed acute and chronic values found in the 1988 parameters that have the greatest impact on
criteria recommendation, these final 2018 aluminum's bioavailability are pH, total hardness,
recommended criteria provide users the flexibility to and DOC.
develop site-specific criteria based on local water ■ pH: a low pH generally makes it easier for
chemistry. aluminum to be dissolved, and therefore more
The EPA released a draft of this criteria in 2017 for bioavailable. At higher pH, aluminum speciation
public comment and has reviewed the comments changes make it more bioavailable.
and updated the document. ■ Hardness: generally, higher hardness values
mean there are more ions present.These ions

compete with aluminum and make aluminum Where can I find more information?
less bioavailable.
For more information and to view the aluminum
■ DOC: higher dissolved organic carbon reduces criteria document and the criteria calculator, please
bioavailability. Aluminum is bound to DOC, visit EPA's website at www.epa.gov/wgc/aquatic-
making the aluminum less bioavailable to aquatic life-criteria-aluminum or email Diana Eignor at
organisms.
[e-mail].
What are the Recommended Criteria for
Aluminum in Freshwater for the Protection
of Aquatic Life?
The recommended aquatic life criteria for aluminum
in freshwater depend on a site's water chemistry
parameters. Unlike the fixed values found in the
1988 criteria document,these criteria use Multiple
Linear Regression (MLR) models to normalize the
toxicity data and provide a range of acceptable
values. The criteria are calculated based on a site's
pH, total hardness, and DOC. See Table 1 for a
comparison of 2018 and 1988 criteria values.
For freshwater criteria, users can enter their site's
water quality parameters into the Aluminum Criteria
Calculator V.2.0.x1sm or use the lookup tables in the
criteria document's appendix. The resulting acute
criterion indicates that freshwater organisms would
be protected if the one-hour average concentration
is not exceeded more than once every three years
on average. The chronic criterion indicates that
freshwater organisms would be protected if the
four-day average concentration is not exceeded
more than once every three years on average.
Table 1: Comparison of the EPA's 2018 and 1988 National Recommended Aquatic Life Criteria for
Aluminum
Freshwater Acute' Freshwater Chronic'
(1 hour, (4-day,
Version total recoverable aluminum) total recoverable aluminum)
2018 Criteria 1-4,800 µg/Lb 0.63-3,200 jig/Lb
(vary as a function of a site's pH,total hardness,and DOC)
1988 Criteria 750 µg/L 87 µg/L
(pH 6.5—9.0,across all total hardness and DOC ranges)
'Values are recommended not to be exceeded more than once every three years on average.
b Values will be different under differing water chemistry conditions.

Whole Effluent Toxicity Testing and Self Monitoring Summary
Newport WWTP NCO021555/001 County: Carteret Region: WIRO Basin: WOK03 Jan Apr Jul Oct SOC JOC:
Ceri7dPF Begin: 4/1/2013 Chr Lim: 82% T NonComp: 7Q10: 0.4 PF: 1.2 IWC: 66.0 Freq: Q
J F M A M J J A S O N D
2020 Pass - - Pass - - Pass - - Pass - -
2021 Pass - - Pass - - Pass - - Pass - -
2022 Fail INVALID>100(P)>100 >100 Pass - - Pass - - Pass - -
2023 Pass - - Pass - - Pass - - Pass - -
2024 Pass - - - - - - - - - - -
Newton-Clark Creek WWTP NCO036196/001 County: Catawba Region: MRO Basin: CTB35 Mar Jun Sep Dec SOC JOC:
Ceri7dPF Begin: 8/1/2021 chr lim:56%@5MGD NonComp: Single 7Q10: 6.0 PF: 5.0 IWC: 56.32 Freq: Q
J F M A M J l A S O N D
2020 - - Pass(s) - >100(P) Pass - - Pass>100(P) - - Pass
2021 - - Pass(S)Pass(5) - - Pass(s)Pass(s)>100(F - - Pass(S)Pass(5) - - Pass(S)Pass(S)
2022 - - Pass(S)Pass(5) - - Pass(5)Pass(S) - - Pass Pass - - >100 Pass Pass
2023 - - Pass Pass - - Pass Invalid Pass - - >100 Pass Pass - - Pass Pass
2024 - - Pass Pass>100 - - - - - - - - -
Norfolk Southern Railway Co.-Linwood NCO029246/011 County: Davidson Region: WSRO Basin: YAD04 Mar Jun Sep Dec SOC JOC:
Ceri24PF Begin: 6/1/2014 Acu lim: 90% NonComp: Single 7Q10: 1.2 PF: 0.317 IWC: 29.0 Freq: Q
J F M A M I J A S O N D
2020 - - H - - - - - Pass - - INVALID
2021 Pass - Pass - - H - - H - - H
2022 - - Pass - - H - - H - - Pass
2023 - - H - - H - - Pass - - H
2024 - - H - - - - - - - - -
Norman H.Larkins WPCF NCO020117/001 County: Sampson Region: FRO Basin: CPF19 Mar Jun Sep Dec SOC JOC:
Ceri7dPF Begin: 2/1/2012 chr lim:90% NonComp: Single 70.10: 0.0 PF: 5.0 IWC: 100 Freq: Q
J F M A M J J A S O N D
2020 - - Pass - - Pass - - Pass - - Pass
2021 - - Pass - - Pass - - Pass - - Pass
2022 - - Pass - - Pass - - Pass - - Pass
2023 - - Pass - - Pass - - Pass - - >100(P)Fail
2024 >100(P)>100 >100(P)>100 >100(P)Pass - - - - - - - - -
North Cary WRF NCO048879/001 County: Wake Region: RRO Basin: NEU02 Feb May Aug Nov SOC JOC:
Ceri7dPF Begin: 1/1/2019 chr lim:90% NonComp: Single 7Q10: 0.30 PF: 12.0 IWC: 90 Freq: Q
J F M A M J J A S O N D
2020 - Pass - - >100(P)Pass - - Pass - - Pass -
2021 - Pass 97.5(P) - - Pass - - Pass - - Pass -
2022 - Pass - - >100(P)Pass - - Pass - - Pass -
2023 - Pass - - Pass - - >100 Pass - - Pass -
2024 - Pass - - Pass - - - - - - -
Leeend: P=Fathead minnow(PimDhales Dromelas).H=No Flow(facilitv is active).s=Solit test between Certified Labs Page 74 of 113