NC0085359_Authorization to Construct_20230630

DocuSign Envelope ID:CDCCDODA-C701-42F3-BD26-OB4B8C4247FA
ot,., STATE
ROY COOPER
Governor
ELIZABETH S.BISER =1�A
Secretary
RICHAM E.ROGERS,JR. NORTH CAROLINA
Director Environmental Quality
June 30, 2023
Mr. John Shutak
Engineering Division Director
Union County Water
500 North Main Street, Suite 600
Monroe,North Carolina 28112-4730
SUBJECT: Authorization to Construct
A to C No. 085359A08
Union County Water
Twelve Mile Creek WRF
NPDES Permit No. NCO085359
Dear Mr. Shutak:
A letter of request for an Authorization to Construct was received December 20, 2022, by
the Division of Water Resources (Division). With additional information received on April 12,
2023, final plans and specifications for the subject project have been reviewed and found to be
satisfactory. Authorization is hereby granted for the construction of modifications to the existing
7.5 MGD Twelve Mile Creek WRF, with discharge of treated wastewater into the Twelve Mile
Creek in the Catawba River Basin.
This authorization results in an increase in design and permitted capacity to 9 MGD, and
is awarded for the construction of the following specific modifications:
Installation of two (2) 1,260 GPM diversion pumps to replace two existing influent pumps
at the Influent Pump Station 1 and abandonment of the existing diversion pump station,
installation of a new Influent Pump Station 2 with one (1) 4,000 GPM influent pumps and
two(2) 5,500 GPM influent pumps, one(1)bio-trickling filter odor control system,one(1)
6,067 SCFM blower for aeration basin, three (3) 1 HP mixers in the MLSS distribution
box, one(1) 100-foot diameter secondary clarifier#4 with 15-foot side water depth, a new
RAS Pump Station B with two (2) 2,300 GPM RAS pumps, one (1) 300 GPM WAS
blending pump, a new chemical facility consisting of two (2) 7,000-gallon metal salts
storage tanks,four(4)0.4 GPM metal salts feed pumps,one(1)50 GPM metal salts transfer
pump, and two(2)25 GPM metal salts containment drain pumps, and all necessary piping
and controls; in conformity with the project plans, specifications, and other supporting
documentation comprising the ATC Permit Application package submitted to the
Department of Environmental Quality.
North Carolina Department of Environmental Quality I Division of Water Resources
N�THcnaouti^
D E Q�� 512 North Salisbury Street 11611 Mail Service Center I Raleigh,North Carolina 27699-1611
919.707.9000
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DocuSign Envelope ID:CDCCDODA-C701-42F3-BD26-OB4B8C4247FA
Mr.John Shutak,Engineering Division Director
June 30,2023
Page 2 of 3
This ATC is issued in accordance with Part III, Paragraph A of NPDES Permit No.
NCO085359 issued effective July 1, 2021, and shall be subject to revocation unless the wastewater
treatment facilities are constructed in accordance with the conditions and limitations specified in
Permit No. NC0085359.
It is the Owner's responsibility to ensure that the as-constructed project meets the
requirements of all applicable regulations and statutes, the ATC Permit Application package, and
all of the requirements contained herein. Failure to comply may result in penalties in accordance
with North Carolina General Statute §143-215.6A through §143-215.6C.
The sludge generated from these treatment facilities must be disposed of in accordance
with G.S. 143-215.1 and in a manner approved by the Division.
In the event that the facilities fail to perform satisfactorily, including the creation of
nuisance conditions, the Permittee shall take immediate corrective action, including those as may
be required by the Division, such as the construction of additional or replacement wastewater
treatment or disposal facilities.
The Mooresville Regional Office, telephone number [phone], shall be notified at
least forty-eight (48) hours in advance of operation of the installed facilities so that an on-site
inspection can be made. Such notification to the regional supervisor shall be made during the
normal office hours from 8:00 a.m. until 5:00 p.m. on Monday through Friday, excluding State
Holidays.
Upon completion of construction and prior to operation of this permitted facility, a
certification must be received from a Professional Engineer certifying that the permitted facility
has been installed in accordance with the NPDES Permit and the ATC Permit Application package.
Mail the Certification to: Division of Water Resources, WQ Permitting — NPDES, 1617 Mail
Service Center, Raleigh,NC 27699-1617.
Upon classification of the facility by the Certification Commission, the Permittee shall
employ a certified wastewater treatment plant operator to be in responsible charge (ORC) of the
wastewater treatment facilities. The operator must hold a certificate of the type and grade at least
equivalent to or greater than the classification assigned to the wastewater treatment facilities by
the Certification Commission.
The Permittee must also employ a certified back-up operator of the appropriate type and
grade to comply with the conditions of T15A:8G.0202. The ORC of the facility must visit each
Class I facility at least weekly and each Class II, III and IV facility at least daily, excluding
weekends and holidays, must properly manage the facility, must document daily operation and
maintenance of the facility, and must comply with all other conditions of T15A:8G.0202.
A copy of the project plans and specifications shall be maintained on file by the
Permittee for the life of the facility.

DocuSign Envelope ID:CDCCDODA-C701-42F3-BD26-OB4B8C4247FA
Mr.John Shutak,Engineering Division Director
June 30,2023
Page 3 of 3
During the construction of the proposed additions/modifications, the Permittee shall
continue to properly maintain and operate the existing wastewater treatment facilities at all times,
and in such a manner, as necessary to comply with the effluent limits specified in the NPDES
Permit.
You are reminded that it is mandatory for the project to be constructed in accordance with
the North Carolina Sedimentation Pollution Control Act, and when applicable, the North Carolina
Dam Safety Act. In addition, the specifications must clearly state what the contractor's
responsibilities shall be in complying with these Acts.
Prior to entering into any contract(s) for construction, the recipient must have obtained all
applicable permits from the State.
The issuance of this ATC does not preclude the Permittee from complying with any and
all statutes,rules,regulations, or ordinances which may be imposed by other government agencies
(local, state, and federal) which have jurisdiction.
If you have any questions or need additional information, please contact Min Xiao, PE at
telephone number(919) 707-3644 or by email at [e-mail].
Sincerely,
E
ADoccuSiig�n�ed bby, `'•�y ',.''`�MM r r"WkitkUh
C464531431644FE...
for Richard E. Rogers, Jr.
Director, Division of Water Resources
by Michael Montebello
Chief,NPDES Permitting Branch
With Engineer's Certificate attached:
cc: NPDES Files
ecopy: Michael Parker, PE
Hazen and Sawyer
Email: [e-mail]
DWR Mooresville Regional Office, Water Quality Programs
DWR NPDES Industrial Permitting Unit/Doug Dowden, Supervisor
Without Engineer's Certificate attached:
cc: Union County Health

Union County Water
Twelve Mile Creek WRF
Authorization to Construct No. 085359A08
Issued June 30, 2023
NPDES Permit No. NCO085359
Engineer's Certification
I, , as a duly registered Professional Engineer in
the State of North Carolina, having been authorized to observe (periodically/weekly/full time)
the construction of the modifications and improvements to the Twelve Mile Creek Water
Reclamation Facility, located in Union County, hereby state that, to the best of my abilities, due
care and diligence was used in the observation of the following construction:
Installation of two (2) 1,260 GPM diversion pumps to replace two existing
influent pumps at the Influent Pump Station 1 and abandonment of the existing
diversion pump station, installation of a new Influent Pump Station 2 with one (1)
4,000 GPM influent pumps and two (2) 5,500 GPM influent pumps, one (1)bio-
trickling filter odor control system, one (1) 6,067 SCFM blower for aeration
basin, three (3) 1 HP mixers in the MLSS distribution box, one (1) 100-foot
diameter secondary clarifier#4 with 15-foot side water depth, a new RAS Pump
Station B with two (2) 2,300 GPM RAS pumps, one (1) 300 GPM WAS blending
pump, a new chemical facility consisting of two (2) 7,000-gallon metal salts
storage tanks, four(4) 0.4 GPM metal salts feed pumps, one (1) 50 GPM metal
salts transfer pump, and two (2) 25 GPM metal salts containment drain pumps,
and all necessary piping and controls; in conformity with the project plans,
specifications, and other supporting documentation comprising the ATC Permit
Application package submitted to the Department of Environmental Quality.
I certify that the construction of the above referenced project was observed to be built within
substantial compliance, intent and in conformity with all applicable regulations and statutes and
the project plans, specifications, and other supporting documentation comprising the
Authorization to Construct Permit Application package.
Signature Registration No.
Date
Mail this Certification to: Attn: Min Xiao, PE SEAL
NPDES Industrial Permitting Unit
DEQ/DWR/Water Quality Programs /
1617 Mail Service Center
Raleigh,NC 27699-1617