NC0025453_Fact Sheet_20230823

Fact Sheet
NPDES Permit No. NCO02.5453
Permit Writer/Email Contact Nick Coco, [e-mail]:
Date: July 13, 2023
Division/Branch: NC Division of Water Resources/NPDES Municipal Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑ Renewal
❑ Renewal with Expansion
❑ New Discharge
❑X 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:
Town of Clayton/Little Creek Water Reclamation Facility (WRF)
Applicant Address:
PO Box 879, Clayton, NC 27528
Facility Address:
1422 N. O'Neil Street, Clayton, NC 27520
Permitted Flow:
2.5 MGD with expansions to 6.0 MGD and 10.0 MGD
Facility Type/Waste:
MAJOR Municipal; 95% domestic, 5% industrial
Facility Class:
Grade IV Biological Water Pollution Control System (WPCS)
Treatment Units:
Mechanical bar screens & grit removal, influent pump station,
anaerobic basin, anoxic tanks, oxidation basins, clarifiers, tertiary
filters, UV disinfection with backup chlorination/dechlorination, aerated
sludge digester, sludge holding tank, sludge thickener, non -potable
reclaimed water system
Pretreatment Program (Y/N)
Y
County:
Johnston
Region
Raleigh
Briefly describe the proposed permitting action and facility background.- The Town of Clayton applied
for an NPDES permit modification for the Little Creek WRF on May 11, 2023, requesting that the Total
Nitrogen loading limitation be revised at the 2.5 MGD flow tier from 22,832 lb/yr to 26,636 lb/yr to
accommodate for an increase in nitrogen loading to the facility experienced over the past year. The Town
is pursuing construction of a greenfield 6.0 MGD facility, Sam's Branch WRF, which would activate the
6.0 MGD flow tier of the permit, but due to construction delays, the Town is realizing the need to request
additional loading be activated from the reserve allocation at the current 2.5 MGD flow. As activation of
reserve nutrient loading is not considered a minor modification listed in 40 CFR 122.63, the modification
is subject to public notice.
Page 1 of 5

Background regarding Sam's Branch WRF: The Town is planning a phased approach to meet current and
projected demands, beginning with construction of a new 6- MGD treatment facility. The proposed
project includes the following major components:
• New 6- MGD water reclamation facility (WRF) constructed on a Town- owned site adjacent to
the Neuse River and including the Town' s existing outfall as a first phase, with anticipated
incremental expansion to 10 MGD to meet future needs
• Abandonment of the Town' s existing LCWRF
• Construction of a pump station at the LCWRF site and associated Little Creek
• Transmission Main infrastructure to convey flow to the new WRF
The Little Creek WRF serves a population of 25,234 residents and operates a pretreatment program with
two pharmaceutical Categorical Industrial Users, Novo Nordisk and Grifols. Currently, Grifols discharges
to Johnston County's WWTP. Clayton has agreements with Johnston County and Raleigh's Neuse River
WWTP to divert up to 1.3 MGD and 1.0 MGD to those plants, respectively. Clayton also operates a
reclaimed water system and land applies up to 237,840 GPD under permit WQ0022224.
2. Receiving Waterbody Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 — Neuse River
Stream Segment:
27-41.3
Stream Classification:
WS-IV;NSW,CA
Drainage Area (m12):
1,150
Summer 7Q10 (cfs)
186 (regulated)
Winter 7Q10 (cfs):
186 (regulated)
30Q2 (cfs):
186 (regulated)
Average Flow (cfs):
186 (regulated)
IWC (% effluent):
1.6 at 2.5 MGD
303(d) listed/parameter:
No
Subject to TMDL/parameter:
Yes- Subject to Neuse nutrient rule 15A NCAC 02B .0234,
Statewide Mercury TMDL implementation.
Basin/Sub-basin/HUC:
Neuse/03-04-02/03020201
USGS Topo Quad:
E25NW/N W Clayton
3. Effluent Data Summary
Nutrient effluent data for Outfall 001 is summarized below for the period of January 2019 — December
2022.
Table 1. Effluent Data Summary Outfall 001
Parameter
Units
Average
Max
Min
Permit
Limit
Flow
MGD
1.6
5.27
0.15
MA 2.5
Total Monthly Flow
MG/mo
49.7
67.796
41.348
Nitrite+Nitrate
mg/1
2.8
9.56
0.05
TKN
mg/1
1.5
11.5
0.2
TN
mg/1
4.2
12.53
0.93
TN Load
lb/mo
1620
2721
662
TN Load
lb/yr
19,772
23,661
16,640
22,832
MA -Monthly Average, WA -Weekly Average, DM -Daily Maximum, DA=Daily Average, QA=Quarterly Average
Page 2 of 5

Other TMDL/Nutrient Manaaement Strateav Considerations
If applicable, describe any other TNDDLs/Nutrient Management Strategies and their implementation
within this permit:
Neuse River Nitrogen TMDL and Nutrient Management Strategy
The Neuse River estuary has an extensive history of nutrient -related water quality impacts and was
classified as Nutrient Sensitive Waters in 1988. Nutrient Management Strategy rules were first adopted in
December 1997 and modified in 2000 and 2020. The wastewater discharge rule, 15A NCAC 2B .0713
(formerly .0234), established requirements for control of Total Nitrogen (TN) from point source
discharges. It requires TN limits for all dischargers with a permitted capacity of 0.5 MGD or greater and
allows the transfer of allocation among the Neuse dischargers so long as the total of estuary allocations
and loads do not exceed those allowed in the 1999 TN TMDL. The rule also sets technology -based limits
for Total Phosphorus (TP).
The wastewater rule provides a group compliance option in which interested dischargers can work
collectively to comply with an aggregate TN limit. Clayton is a co-permittee member of the Neuse River
Compliance Association, whose group NPDES permit, NCC000001, was last re -issued December 12,
2018. Co-permittee members are deemed to be in compliance with the TN limits in their individual
permits and are instead subject to the aggregate limit established in the group permit. The group's TN
limit is the sum of the members' active estuary allocations.
Nitrogen Allocations and Offset Credits
In accordance with the Neuse rule, the Town of Clayton was assigned a base Total Nitrogen (TN)
discharge allocation of 21,400 lb/yr. This was the basis for its original (2003) TN discharge limit. Based
on its location in the basin, the facility was assigned a transport factor of 50%; thus, its discharge
allocation is equivalent to 10,700 lb/yr delivered to the estuary. Transport factors and delivered loads
come into play when transferring allocation or offset credits to or from a discharger.
The Town has experienced significant growth since the early 2000s and in 2006 was permitted to
expanded to 2.5 MGD. To meet additional needs, the Town acquired 3,668 lb/yr estuary nitrogen
allocation from South Granville WASA (NC0026824) in 2006, 1,645 lb/yr from UNIFI-Kinston
(formerly and once again, DuPont -Kinston, NC0003760) in 2007.
In 2020, The transactions were conducted in accordance with the Neuse River nutrient strategy and rule.
In September 2020, the Town acquired nitrogen offset credits from RS Flat Swamp, LLC. RS Flat Swamp
is the Bank Sponsor for the RS Flat Swamp Buffer & Nutrient Offset Mitigation Bank, a mitigation
project undertaken to generate nutrient offset credits. The transaction was conducted in accordance with
the Neuse strategy and the procedures of the Division's Nutrient Offset and Riparian Buffer Mitigation
Banking Program. These procedures included submittal of a Letter of Intent to purchase offset credits
from the Town and the Bank Sponsor, a Statement of Nutrient Offset Credit Availability by the Bank
Sponsor, and a Nutrient Offset Credit Transfer Certificate by the Sponsor upon payment and completion
of the transaction. (See the September 20, 2020, Fact Sheet for further details.)
Also in September 2020, the Town acquired 13,000 lb/yr of estuary TN allocation from International
Paper —New Bern (NC0003191). One purpose of this modification is to note the additional reserve
allocation in the Town's permit. International Paper's permit is being modified at the same time to reflect
the 13,000 lb/yr reduction in its TN allocation and limit.
The Town's TN allocation and offset credit holdings are listed in Tables 2-4 for the 2.5, 6.0, and 10.0
MGD tiers of the permit. The tables also note the resulting TN Load limits at each flow tier. At 2.5 and
6.0 MGD, the total allowance (allocation plus offset credits) exceeds the Neuse rule's technology -based
cap of 3.5 mg/L for existing facilities, and the excess allowance is held in reserve. At 10.0 MGD, the
Page 3 of 5

Town's entire allowance is equivalent to 2.95 mg/L TN and so can be applied toward its TN Load limit.
(The equivalent TN concentrations in the tables indicate the level of treatment required at design flow but
will not be included as limits in the permit.).
The Town is requesting modification to the permit to increase the TN Load limit at the existing 2.5 MGD
to 26,636 lb/yr, which is equivalent to the Neuse rule's technology -based cap of 3.5 mg/L. Table 2 has
been revised to reflect this proposed change.
Table 2. Allocations and Offset Credits - 2.5 MGD
ALLOCATION/ CREDITS AMOUNT
SOURCE
STATUS
Estuary
Discharge
Equiv TN
(lb/yr)
(lb/yr)
(mg/L)
Assigned by Rule
10,700
21,400
Active
Purchased from South Granville
3,668
7,336
Mixed
WASA (NC0026824)
973
1,946
Active
2,695
5,390
Reserve
Purchased from UNIFI-Kinston
1,645
3,290
Active
(NC0003760)
Purchased from
RS-Flat Swamp, LLC (Flat Swamp
15,908
31,816
Reserve
Mitigation Bank)
Purchased from International Paper,
NC0003191
13,000
26,000
Reserve
TOTAL
44,921
89,842
Mixed
13,318
26,636
3.5
Active
31,603
67,010
Reserve
The current permit mistakenly does not provide the appropriate active and reserve TN allocations for the
6.0 MGD flow tier. As such, Special Condition A.(8.) Total Nitrogen Allocations and Offset Credits,
Table 2. Allocations and Offset Credits has been corrected as part of this modification. The Town's TN
allocation and offset credit holdings at the 6.0 MGD flow tier are listed in Tables 3 below. No changes are
proposed for the 10.0 MGD flow tier.
Table 3. Allocations and Offset Credits - 6.0 MGD
ALLOCATION/ CREDITS AMOUNT
SOURCE
STATUS
Estuary
Discharge
Equiv TN
(lb/yr)
(lb/yr)
(mg/L)
Assigned by Rule
10,700
21,400
Active
Purchased from South Granville
3,668
7,336
Active
WASA (NC0026824)
Purchased from UNIFI-Kinston
1,645
3,290
Active
(NC0003760)
Purchased from
RS-Flat Swamp, LLC (Flat Swamp
15,908
31,816
Active
Mitigation Bank)
Purchased from International Paper,
13,000
26,000
Mixed
NC0003191
42
84
Active
12,958
25,916
Reserve
TOTAL
44,921
89,842
Mixed
31,963
63,926
3.50
Active
12,958
25,916
Reserve
Page 4 of 5

4. Antibacksliding and Antidegradation Review:
Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations
may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit (YESINO): YES
If YES, confirm that antibacksliding provisions are not violated. Per 15A NCAC 2B .0713(8)(d), the
nitrogen discharge limit for an expanded facility shall not exceed the nitrogen loading equivalent to its
active allocation and offset credits, or the mass equivalent to a concentration of 3.5 mg/L at the at the
monthly average flow limit in the facility's modified NPDES permit, except that the limit shall be no less
than the facility's original allocation. In 2006, when the Town was permitted to expand the Little Creek
WRF to 2.5 MGD, the TN load limit was set at an equivalent concentration of 3.0 mg/L, less than the
technology -based limit noted in 15A NCAC 02B .0713. This is considered a "technical mistake or
mistaken interpretation of law," which is an exemption from the anti -backsliding regulations outlined in
CWA 402(o)(2). In addition, the facility has demonstrated that it does not consistently meet the TN load
limit based on the equivalent concentration of 3.0 mg/L.
5.Summary of Proposed Permitting Actions:
Table 4. Current Permit Conditions and Proposed Changes 2.5 MGD
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
TN Load
Active loading of 22,832
Active loading of
WQBEL. 15A NCAC 2B .0713.
lb/yr
26,636 lb/yr
Revision of active loading at 2.5
MGD to reflect 3.5 mg/L equivalent
Correction of typo
per rule; Based on increasing
related to active and
influent loading and delayed
reserve allocations at
construction of Sam's Branch WRF
6.0 MGD tier
MGD — Million gallons per day, MA - Monthly Average, WA — Weekly Average, DM — Daily Max
6. 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.
7. 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
Page 5 of 5

MAYOR
Jody L. McLeod
MAYOR PRO TEM
Jason Thompson
TOWN MANAGER
Richard D. Cappola, Jr.
TOWN ATTORNEY
Cauley Pridgen, P.A.
May 11, 2023
Richard Rogers - Director
Division of Water Resources
1617 Mail Service Center
Raleigh NC 27699-1617
RE: Request for Modification to NPDES permit, Permit No. NCO025453
Director Rogers:
COUNCIL MEMBERS
Andria Archer
Porter Casey
Avery Everett
Michael Sims
The Town of Clayton (Town) is requesting a modification to the Town's NPDES permit, Permit No. NCO025453
(Permit). Specifically, the Town is requesting Total Nitrogen (TN) allocation credits be changed from reserve to active
status.
The current permit includes a TN load limit of 22,832 lbs./yr. associated with the current 2.5 MGD Little Creek
Water Reclamation Facility (WRF). This load limit is based on active allocation credits; however, the Town does have
reserve allocation as noted in Condition A. (8) of the Permit. While the load limit increases to 63,926 lbs./yr. when the
Sam's Branch WRF is completed (Footnote 6 to permit condition A. (2.) - Effluent Limits 6.0 MGD), the Town has
realized the need to increase the load at its current capacity (2.5 MGD) due to the delays in construction of the Sam's
Branch WRF.
This request is assumed to be a minor modification with respect to fees since the permit already allows the TN load
(i.e., the permitting action does not create a new load), however we understand the action would not be considered
minor with respect to 40 CFR 122.63 and would require public notice. We are making this request with sufficient time
for the Division of Water Resources (Division) to process this request prior to the end of year as modifications to the
TN load limit are required to go into effect January 1 of the following year of the modification pursuant to permit
condition A.(7.)d.iii. This letter requesting a modification reflects the City of Raleigh's request to modify their
respective nitrogen allocation dated August 10, 2021. Our request differs from the City of Raleigh's request in that the
Permit already includes the allocation.
Please inform the Town as soon as possible if a fee or other information is required. Our consultants, HDR
Engineering, Inc. of the Carolinas, requested information on the submittal requirements in multiple emails to the
Division but the email recipients did not respond.
If you do need any additional information, please feel to contact me at 919-553-5002 or
Rcappola4TownofClaytonNC.org.
Sincerely,
IV
hadPpplajr., PE, MPA, CFM
Town Manager
cc: Adam Sharpe - HDR Engineering Inc. of the Carolinas
Haywood Phthisic - Lower Neuse Basin Association (LNBA)
Enclosures
Uk,ft7N
AROL�NA
PO Box 879 • Clayton, NC 27528 • 919-553-5002 Fax [phone] • TownofClaytonNC.org

MAYOR
Jody L. McLeod
MAYOR PRO TEM
Jason Thompson
TOWN MANAGER
Richard D. Cappola, Jr.
TOWN ATTORNEY
Cauley Pridgen, P.A.
June 28, 2023
Nick Coco, PE
NPDES Municipal Permitting Unit
Division of Water Resources
1617 Mail Service Center
Raleigh NC 27699-1617
Mr. Coco:
COUNCIL XIEAME,RS
Andria Archer
Porter Casey
Avery Everett
Michael Sims
Thank you for your review of the Town of Clayton's (Town) modification request for the Town's NPDES
permit, Permit No. NCO025453 (Permit) to change allocation credits from reserve to active status. Below
are our responses to your request for additional information.
DWR Request
• Please prowde a speck amount ofloading that the Town is requesting to activate for the
existing flow tier.
o As you noted and are aware, the loading changes would take effect beginning on
_January 1, 2024. The group permit will need momcation duringits renewal to update
the table once this momcation has been completed
o Please note that, per 15A NCAC2B . 0713, the maximum TNIoadingavailable would
be based on a mass equivalent to a concentration of3.5mg/L.
Town Response
The Town is requesting the active Total Nitrogen (TN) load be increased to 26,636 lbs./yr. based
on our current Little Creek Water Reclamation Facility (LCWRF) flow limit of 2.5 MGD and your
referenced maximum concentration equivalent of 3.5 mg/L TN. This would increase the current
active allocation (i.e., 22,832 lbs./yr.) by 3,804 lbs./yr. The 3,804 lbs./yr. of TN is a small portion of
the Town's reserve allocation.
DVVR Request
• Please prornde justification/rationale for the Town's need for thls adjustment to the total
nitrogen loading at the existingilow tier. As you noted, much of the reserved TNloadingis to
be activated upon expansion ofthe facility, which was permitted in a recentpermithngaction.
Please explain whathas changed that necessitates the increased load limit at 2.5MGD.
Ukft7NPO Box 879 •Clayton, NC 27528 • 919-553-5002 AROINA
Fax [phone] • ClaytonNC.org • Page 1 of 2

Town Response
As noted above, the basis of the request is the current LCWRF flow limit of 2.5 MGD and
maximum TN concentration of 3.5 mg/L as allowed by 15A NCAC 2B .0713. The current active
allocation is based on the March 15, 2010, permitting action that increased the active TN allocation
to 22,832 lbs./yr. with additional credits held in reserve. Ideally this resulting active load allocation
for LCWRF would have provided sufficient time for construction of the Town's new greenfield 6
MGD Sam's Branch WRF (SBWRF). However, that active TN load limit was exceeded in 2022
and some of the reserve allocation previously purchased is now required before construction of the
SBWRF is complete. Increasing the TN active allocation to 26,636 lbs./yr. will provide TN load
capacity through 2025. This increase, along with the continued utilization of interconnections with
the City of Raleigh and Johnston County, will allow the Town to meet capacity demands.
Construction of the SBWRF is anticipated to be completed in 2025.
If you need any additional information, please feel to contact me at 919-553-5002 or
Rcappola@TownofClaytonNC.o.
Sincerely,
/ r
Richard D. appola Jr.
Town Manager
cc: Adam Sharpe - HDR Engineering Inc. of the Carolinas
L Vbd�
PO Box 879 • Clayton, NC 27528 • 919-553-5002 NORTHCAROWNA Fax [phone] • ClaytonNC.org • Page 2 of 2