NC0024945_authorization to construct_20100217

A7A
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
February 17, 2010
Mr. Tom Howard, P.E.
Charlotte -Mecklenburg Utilities
5100 Brookshire Blvd.
Charlotte, North Carolina 28216
SUBJECT: Authorization to Construct
A to C No. 024945A02
Charlotte Mecklenburg Utilities
Irwin Creek WWTP
Mecklenburg County
Dear Mr.Howard:
A letter of request for an Authorization to Construct was received August 19, 2009, by
the Division of Water Quality (Division), and 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 15.0 MGD Wastewater Treatment Plant, with
discharge of treated wastewater into Irwin Creek in the Catawba River Basin.
This authorization results in no increase in design or permitted capacity and is awarded
for the construction of the following specific modifications:
Reconfiguration of the existing plant influent pump station, piping, and headworks
including a new concrete influent flow diversion structure, the addition of a 12.5 mgd
submersible non -clog flow equalization pump, a new influent flow meter; four (4) new
7000 gpm horizontal, non -clog influent pumps; a new force main effluent structure; three
(3) new 25 mgd peak flow mechanical bar screens; two (2) new 30 mgd stirred vortex grit
collectors, a new 2 hp grit removal mixer, three (3) new 250 gpm grit cyclones, two (2)
new 250 gpm grit classifiers; a new 150 cfh screw conveyor; two (2) new 600 cfh
screenings belt conveyors and two (2) new 32 cfh screenings presses; reconfiguration of
the existing primary clarifiers by adding a new concrete primary clarifier distribution
structure and increasing the sidewater depths 3.1 ft to a total of 13.7 ft, installation of
new v-notch weir plates in each primary clarifier; three (3) new 200 gpm recirculating
chopper scum pumps, two new (2) 100 gpm progressive cavity scum pumps; demolition
of the existing intermediate lift station; demolition of three (3) trickling filters; three (3)
5500 scfm blowers; three (3) 6640 scfm high-speed blowers; four (4) 5 hp distribution
channel vertical mixers, and 10 three (3) hp vertical mixers for phosphorus removal in the
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone] \ Customer Service: 1-877-623-6748
Internet: www.ncwaterquality.org
An Equal Opportunity 1 Affirmative Action Employer
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Mr. Tom Howard, P.E.
A to C No. 024945A02
Issued February 17, 2010
South aeration basins, a new aeration basin effluent junction box; refurbishment of the
secondary clarifying system with construction of one (1) 125-ft diameter 14.5-ft side
water depth concrete secondary clarifier; one (1) 3500 gpm horizontal non -clog RAS
pump; one (1) 300 gpm horizontal non -clog WAS pump; one (1) 50 gpm progressive
cavity scum pump; relocation of chemical storage and delivery with a new chemical
storage building, two (2) 12-ft diameter 18-ft side depth carbon steel sodium hydroxide
storage tanks, two (2) 170 gph caustic solution metering pumps; two (2) 12-ft diameter
13-ft side depth fiberglass reinforced plastic metal salt storage tanks, four (4) 66 gph
metal salt metering pumps; 10 effluent filter distribution weirs; refurbishment of solids
handling facilities including two (2) gravity belt thickener pumps, one (1) 10-ft diameter,
14-ft sidewall polymer storage tank, one 15 gpm thickening polymer tank mixing pump,
one (1) 25 gpm dewatering polymer mixing pump, two (2) 60 gph progressive cavity
thickened WAS pumps, four (4) 100 gpm primary sludge pumps, one (1) 750 gpm
primary sludge drain pump, four (4) 360 gpm heat exchangers, two (2) 160 gpm
progressive cavity digested sludge pumps, two (2) 230 scfm digester gas compressor
blowers, six (6) 300 gpm digestor gas recirculation pumps, two (2) 375 gpm progressive
cavity gravity belt thickeners, two (2) 300 gph dilution water feed pumps, two (2) 2-
meter wide gravity belt filter presses, and one (1) 58-ft diameter 20-ft sidewater depth
filtrate equalization tank; relocation of the 44 kV substation; influent pump station
electrical building; and associated yard piping, electrical work and control systems in
conformity with the project plans, specifications, and other supporting data subsequently
filed and approved by the Department of Environment and Natural Resources.
This Authorization to Construct is issued in accordance with Part III, Paragraph A of
NPDES Permit No. NC0024945 issued June 1, 2005, and shall be subject to revocation unless
the wastewater treatment facilities are constructed in accordance with the conditions and
limitations specified in Permit No. NC0024945.
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

Mr. Tom Howard, P.E.
A to C No. 024945A02
Issued February 17, 2010
has been installed in accordance with the NPDES Permit, this Authorization to Construct and the
approved plans and specifications. Mail the Certification to: Construction Grants & Loans,
DWQ/DENR, 1633 Mail Service Center, Raleigh, NC 27699-1633.
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 approved plans and specifications shall be maintained on file by the
Permittee for the life of the facility.
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.
Failure to abide by the requirements contained in this Authorization to Construct may
subject the Permittee to an enforcement action by the Division 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.
One (1) set of approved plans and specifications is being forwarded to you. If you have
any questions or need additional information, please contact Seth Robertson, P.E. at telephone
number [phone].

Mr. Tom Howard, P.E.
A to C No. 024945A02
Issued February 17, 2010
Sincerely,
it( Coleen H. Sullins
swc:sr
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cc: James N. Struve, P.E. — Hazen and Sawyer, PC, 4944 Parkway Plaza Blvd., Suite 375,
Charlotte, NC 28217
Mecklenburg County Health Department
Mooresville Regional Office, Surface Water Protection
Technical Assistance and Certification Unit
Point Source Branch, NPDES Program
Steve Coffey, P.E.
ATC File 024945A02