NC0021156_authorization to construct_20030826

NI'�DES DOCUWEN'I' SCANNINO COVER SHEET
NPDES Permit:
NC0021156
Mount Holly WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct
(AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
January 30, 2003
This 3ocument is printed on reuse paper - ignore aay
content on the reverse side

132 W. Statesville Ave.
Mooresville, NC 28115
2-8192
INENCO x: (7 4) 662-81
1 �rC Fax: [phone]
August 26, 2003
NPDES Unit
NC DENR / DWQ
1617 Mail Service Unit
Raleigh, NC 27699-1617
Re: Modification to NPDES Permit No. NC0021156: City of Mount Holly W WTP:
Dechlorination Addition.
Dear Sir;
There has been one change made in the original plans for the addition of a dechlorination system
to the Mt. Holly wastewater treatment plant. There are only two (2) sulfur dioxide tanks instead
of three (3) on site. These tanks are interconnected, and will automatically switch over when one
tank is low. There are also weigh scales on each tank. I feel that this change will have no impact
on the operation of the facility; however, I did want to notify you of this change.
Sincerely Yours,
James W. Gilpin, PE
Principal Consultant
cc: Mr. Don Price,
Utility Director
City of Mount Holly
j
AUG 2 7 2003

Mr. Price
NM021 156
4
Engineer's Certification
1, J*VE5 li/. , 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 project. *,. AL4Y W WTP %DCrNccPiWRTe,J _, I--&Y , N G for the
Project Name Location
Permittee hereby state that. to the best of my abilities, due care and diligence was used in the
observation of the following installations:
Addition of flow proportional dual gas chlorine feed system with automatic switchover.
. 3 chlorine gas tanks (2 to feed each contact chamber. I as back-up)
Addition of flow proportional dual sulfur dioxide feed system with automatic switchover (to be
applied after the weir at the chlorine contact chamber),
.2,8'S02 tanks (2 to feed each contact chamber.)
and all additional piping, valves, control equipment and appurtenances.
Once modifications approved under this ATC have been completed and an Engineer's Certificate
has been submitted the perrnittee is authorized to operate the units listed above. This Authorization to
Construct does not alter the current design flow of 4 MGD for the City of Montt Holy. As you are aware,
the contact time for chlorine contact basin #1 is under the required 30 minutes at the design flow of 4
MGD. The Division advises the City to provided additional contact time as the City approaches design
flow, in order to consistently meet the fecal coliform limit. Should the City be chronically
noncompliant with the fecal coliform limit, the Division may require that additional chlorine contact
time be provided at the treatment plant.
This Authorization to Construct is issued in accordance with NPDES Permit No. NCO021156
issued March 14, 2002 (modification issued May 15, 2002). and shall be subject to revocation
unless the wastewater treatment facilities are constructed in accordance with the conditions and
limitations specified in the permit.
Signature --� ��''�.+/% Registration No./✓L/'E /%Z41
Date 0�Z�r�J=3
Mail this Certification to the
NPDES Unit
DENR/DWg
1617 Mail Service Center
Raleigh. NC 27699-1617
m

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
Alan W. Klimek, P.E., Director
Mr. Don Price, Utility Director
City of Mount Holly
131 South Main Street
Mount Holly, North Carolina 25120
Dear Mr. Price:
INA
NCDENR
NORTH CAROUNA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
January 30, 2003
Subject: Authorization to Construct Permit Issuance
ATC Number 021156A01
Mt. Holly WWTP
NPDES Permit NCO021156
Gaston County
A request for an Authorization to Construct (ATC) was received by the Division and final plans
and specifications for this project have been reviewed and found to be satisfactory. Authorization is
hereby granted for the Mt. Holly Wastewater Treatment Plant improvements. Specifically, this ATC
allows:
Addition of flow proportional dual gas chlorine feed system with automatic switchover,
3 chlorine gas tanks (2 to feed each contact chamber, 1 as back-up)
Addition of flow proportional dual sulfur dioxide feed system with automatic switchover (to be
applied after the weir at the chlorine contact chamber),
• 3 S02 tanks (2 to feed each contact chamber, 1 as back-up)
and all additional piping, valves, control equipment and appurtenances.
Once modifications approved under this ATC have been completed and an Engineer's Certificate
has been submitted, the permittee is authorized to operate the units listed above. This Authorization to
Construct does not alter the current design flow of 4 MGD for the City of Mount Holly. As you are aware,
the contact time for chlorine contact basin # 1 is under the required 30 minutes at the design flow of 4
MGD. The Division advises the City to provided additional contact time as the City approaches design
flow, in order to consistently meet the fecal coliform limit. Should the City be chronically
noncompliant with the fecal coliform limit, the Division may require that additional chlorine contact
time be provided at the treatment plant.
This Authorization to Construct is issued in accordance with NPDES Permit No. NCO02IL156
issued March 14, 2002 (modification issued May 15, 2002), and shall be subject to revocation
unless the wastewater treatment facilities are constructed in accordance with the conditions and
limitations specified in the permit.
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 North Carolina Division of Water Quality.
1617 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699-161 7 -TELEPHONE [phone]/FAX [phone]
AN EQUAL OPPORTUNITY AFFIRMATIVE ACTION EMPLOYER - 50% RECYCLED/ 1 0% POST -CONSUMER PAPER
VISIT US ON THE WEB AT http://h2o.enrstate.nc.us/NPDES

Mr. Price
NCO02ii56
2
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
this 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 in -place
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 classification of the facility by the Certification Commission, the Permittee shall employ a
certified water pollution control treatment system operator to be in responsible charge (ORC) of the
water pollution control treatment system. The operator must hold a certificate of the type and grade at
least equivalent to or greater than the classification assigned to the water pollution control treatment
system 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 Title 15A, Chapter 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, and must properly manage and document daily
operation and maintenance of the facility and must comply with all other conditions outlined in Title
15A, Chapter 8G, .0204. Once the facility is classified, the Permittee must submit a letter to the
Certification Commission which designates the operator in responsible charge within: (A) Sixty
calendar days prior to wastewater being introduced into a new system or (B) within 120 calendar days
of the following, (i) after receiving notification of a change in the classification of the system requiring
the designation of a new ORC and back-up ORC or (ii) a vacancy in the position of ORC or back-up
ORC.
A copy of the approved plans and specifications shall be maintained on file by the Permittee for
the life of the facility.
The Operational Agreement between the Permittee and the Environmental Management
Commission is incorporated herein by reference and is a condition of this Permit. Noncompliance with
the terms of the Operational Agreement shall subject the Permittee to all sanctions provided by G. S.
143-215.6 for violation of or failure to act in accordance with the terms and conditions of this Permit.
Failure to abide by the requirements contained in this Authorization to Construct may subject
the Permittee to an enforcement action by the Division of Water Quality in accordance with North
Carolina General Statute 143-215.6A to 143-215.6C.
The issuance of this Authorization to Construct 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.
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, this Authorization to Construct and the approved plans and
specifications. Mail the Certification to the NPDES Unit, Division of Water Quality, 1617 Mail Service
Center, Raleigh, NC 27699-1617.

Mr. Price
NC0021156
3
One (1) set of approved plans and specifications is being forwarded to you. If you have any
questions or need additional information, please contact Ms. Susan A. Wilson, P.E., telephone number
[phone], extension 510.
Sincerely,
ow
�40dan W. Klimek, P.E.
cc: Central Files
NPDES Unit, Permit File
Mooresville Regional Office, Water Quality

SOC PRIORITY PROJECT: No
To: Permits and Engineering Unit
Water Quality Section
Attention: Susan Wilson
Date: January 16, 2003
AUTHORIZATION TO CONSTRUCT
NPDES PERMIT
REPORT AND RECOMMENDATIONS
County: Gaston
MRO No.: 03-01
Permit No. NCO021156
PART I - GENERAL INFORMATION
1.
2.
3.
4.
5.
A
7
Facility and Address: Mt. Holly WWTP
City of Mount Holly, NC 28120
Date of On -Site Investigation (if conducted): N/A
Report Prepared By: B. D. Browder, Environ. Engr. I
Persons Contacted and Telephone Number: Jim Gilton , [phone].
Verified Discharge Point(s), List for All Discharge Points:
Latitude: 350 15' 55" Longitude: 81 ° 00' 35"
J4-v
< 8 2003
Attach a USGS map extract and indicate treatment facility site and discharge point on
map.
USGS Quad No.: F 14 SE Mount Holly, NC
Site size and expansion area consistent with application? N/A
Topography (relationship to flood plain included): Slopes range from 2 to 6%. The site
is not located ina flood plain.
8. Location of Nearest Dwelling: No dwellings within 500 feet of the site.

Page 2
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. Existing Treatment Facility
a. Current permitted capacity: 4.0 MGD.
b. Date(s) and construction activities allowed by previous ATCs issued in the
previous two years: N/A.
C. Actual treatment capacity of the current facility (design volume): 4.0 MGD.
d. Description of existing or substantially constructed WWT facilities: The existing
activated sludge waterwater treatment facilities consist of two manually cleaned influent
bar screen, dual grit chambers, instrumental flow measurement, a flow equalization basin,
three aeration basins with mechanical aeration, dual secondary clarifiers, dual chlorine
contact chambers, two old clarifiers used for sludge storage if needed, two above ground
sludge tanks (formally digesters)also for sludge storage if needed, two 750,000 gallon
sludge holding tanks, dual sand drying beds (not in use), and a polymer feed system.
2. Type of Proposed Treatment Facility: The applicant proposes to upgrade the chlorine
delivery system, in both contact units, and install a new sulfur dioxide delivery system,
also a dual unit application, for the purpose of wastewater dechlorination and the
polishing of treated effluent.
3. Residuals Handling and Utilization/Disposal Scheme:
a. Land applied, DWQ Permit No.: WQ0001863
Residuals Contractor: Southern Soil Builders
Telephone No.: 336.957.8909
b. Residuals Stabilization: PSRP
C. Landfill: N/A
d. Other disposal/utilization scheme: N/A.
4. Treatment Plant Classification: Class III
5. SIC Code(s): 4952
Wastewater Code(s): 01,
Main Treatment Unit Code: 02003
6. Important SOC/JOC or Compliance Schedule Dates: N/A

Page 3
PART III - EVALUATION AND RECOMMENDATIONS
This office recommends the approval of the ATC for the installation of dechlorination at the Mt.
Holly WWTP.
Signature of Report Preparer Da e
Water Quality R41bnal Supervisor 15ate
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