NC0036277_Authorization to Construct_19951128

NPDES DOCUWENT SCANNING COVER SHEET
NPDES Permit:
NC0036277
McDowell Creek 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:
November 28, 1995
This document is printed on reuse paper. - ignore a.ny
content on the reverse side

State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Environmental Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
November 28, 1995
Mr. Douglas O. Bean
Charlotte Mecklenburg Utility Department
5100 Brookshire Boulevard
Charlotte, North Carolina 28216
T L I
E)EHNR
Subject: Permit No. AC0036277
Authorization to Construct
CMUD - McDowell Creek WWTP
Mecklenburg County
Dear Mr. Bean:
A letter of request for an Authorization to Construct was received August 23, 1995 by the Division
and plans, specifications and final calculations for the subject project have been reviewed and found to be
satisfactory. Authorization is hereby granted for the modification of the existing wastewater treatment
plant to include the following:
• Removal of the existing coarse bar screen, mechanical bar screen, grit scraper, grit pump, grit piping
and appurtenances;
• Abandonment and filling of the existing grit basin;
• A new mechanical bar screen and relocation of the existing bypass bar screen to the influent channel;
• Replacement of existing pneumatic instrumentation;
• One (1) new and one (1) replacement 3,150 gpm pump in the influent pumping station providing a
total pumping capacity of 13,400 gpm;
• A new magnetic flow meter;
• A preliminary treatment structure consisting of: two (2) fine bar screens, a grit removal system (two
(2) grit chambers, grit pumping, two (2) 130 scfm blowers, grit washing and two (2) screw
conveyors), a grit basin, and two (2) belt conveyors;
• Replacement of the existing primary clarifier sludge lines with 6-inch piping and installation of five
(5) 300 gpm pumps in the existing primary sludge pumping station;
• Two (2), four -cell, 24,680 gallon anaerobic basins with one (1) 7.5 hp submersible mixer per cell;
• Installation of partitions in two (2) existing aeration basins to provide anoxic and oxic zones, each
anoxic zone having one (1) 7.5 hp submersible mixer;
• Conversion of two (2) intermediate clarifiers and one (1) final clarifier into aeration basins;
• Refurbish two (2) existing blowers (3418 scfm each) and relocate two (2) existing blowers (4519
scfm each) providing a total capacity of 15,874 scfm;
• A sodium hydroxide feed system with a 12,000 gallon storage tank and two (2) feed pumps;
• One (1) 70-foot diameter primary clarifier,
• Two (2) 100-foot diameter final clarifiers each with two (2) 0.15 hp flocculators;
• An effluent filter structure - three (3) 2100 gpm return sludge pumps, two (2) 100 gpm scum
^ pumps, two (2) 15 gpm thickened sludge pumps, a gravity belt thickener, a dual polymer feed
sludge conditioning system, a deep -bed sand filter with five (5) 500 square foot cells (two (2) 3,000
gpm backwash pumps and two (2) 2,500 icfm backwash air blowers), an acetic acid/methanol feed
system, an ultraviolet disinfection system with six (6) lamp modules, and cascade reaeration;
• Refurbish one (1) sludge storage tank and two (2) primary digesters;
P.O. Box 29535, Raleigh, North Carolina 27626.0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10% post -consumer paper

Permit No. NCO036277
Authorization to Construct
CMUD - McDowell Creek
November 28, 1995
Page 2
• Conversion of an existing final clarifier to an emergency sludge holding basin;
• Two (2) 225 gpm belt thickener sludge feed pumps;
• An alum feed system for supplemental phosphorus removal;
• An alkalinity monitoring system;
• Distribution piping allowing facility operation under any of the following nutrient removal
processes: VIP/UCT, modified UCT, modified OWASA, and CNC;
and all associated piping, valves, controls, and appurtenances. These improvements will increase the
treatment capacity to 6.0 MGD, with discharge of treated wastewater into McDowell Creek in the Catawba
River Basin.
This Authorization to Construct is issued in accordance with Part III, Paragraph C of NPDES
Permit No. NCO036277 issued October 2, 1995, and shall be subject to revocation unless the wastewater
treatment facilities are constructed in accordance with the conditions and limitations specified in Permit No.
NC0036277.
The sludge generated from this treatment facility must be disposed of in accordancewith G.S. 143-
215.1 and in a manner approved by the North Carolina Division of Environmental Management.
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 704-663-1699 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 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 Permits and Engineering Unit, P.O. Box 29535, Raleigh, NC
27626-0535.
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 Title 15A, Chapter 8A, .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 of Title 15A, Chapter 8A, .0202.
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.E for violation of or failure to act in accordance with the terms and conditions of this Permit

/1
Permit No. NC0036277
Authorization to Construct
CMUD - McDowell Creek
November 28, 1995
Page 3
Failure to abide by the requirements contained in this Authorization to Construct may subject the
Permittee to an enforcement action by the Division of Environmental Management 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 Greg Nizich, telephone number 919/733-5083,
ext. 541.
cc: Central Files
Mecklenburg County Health Department
Mooresville Regional Office, Water Quality
Technical Assistance and Certification Group
Facility Assessment Unit
Mr. David Parker, Black & Veatch
NPDES Files
Sincerely,
�. Prestq�i owar��E.

SOC Priority Project: No
.f
To: Permits and Engineering Unit
Water Quality Section
Attention: Greg Nizich
Date: October 10, 1995
NPDES STAFF REPORT AND RECOMMENDATION
County: Mecklenburg .
Permit No. NCO036277
ACA036277
PART I - GENERAL INFORMATION
1. Facility and Address: Charlotte - Mecklenburg Utility Dept.
McDowell Creek WWTP
5100 Brookshire Boulevard
Charlotte, North Carolina 28216
2. Date of Investigation: September 14, 1995 (visited site for Phase I A to C)
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3. Report Prepared by: Todd St. John
4. Persons Contacted and Telephone Number: Peter Goins, Plant Operator [phone]
5. Directions to Site: From the intersection of SR 2128 (Beatties Ford Road) and SR 2074
(Neck Road), travel west on SR 2074 approximately 1.9 miles. The WWTP is located on
the right side of SR 2074 after crossing McDowell Creek.
A
7.
8.
a
Discharge Point(s), List for all discharge points:
Latitude: 35° 22' 52" Longitude: 80° 56' 25"
Attach a USGS map extract and indicate treatment facility site and discharge point on map.
USGS Quad No.: F 15NW USGS Quad Name: Lake Norman South, NC
Site size and expansion area consistent with application? Adequate area exists for the
proposed expansion. Yes
Topography (relationship to flood plain included): Moderately sloping, neither the WWTP
nor the expansion area are located within the 100 year flood plain.
Location of nearest dwelling: None within 1000 feet.

10. Receiving stream or affected surface waters: McDowell Creek
a. Classification: WS-IV CA
b. River Basin and Subbasin No.: Catawba 030833
C. Describe receiving stream features and pertinent downstream uses: Small slow
moving stream, there are several small wetland areas adjacent to the creek. The
CMUD water intake is located a few miles downstream on Mountain Island Lake.
The lake is also used for primary and secondary recreation.
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. a. Volume of wastewater to be permitted: 6.0 MGD (ultimate design capacity)
b. Current permitted capacity of the wastewater treatment facility: 3.5 MGD
C. Actual treatment capacity of the current facility (current design capacity): 3.5 MGD
d. Date(s) and construction activities allowed by previous Authorizations to Construct
issued in the previous two years: Phase I authorization to construct will be issued
after the fact to replace sock diffusers (in the latter 2/3 of each aeration tank) with
flexible membrane diffusers.
e. Please provide a description of existing or substantially constructed wastewater
treatment facilities: The existing W WT facilities consist of 2 manual bar screens, grit
removal, influent pumping, 2 primary clarifiers, 2 trickling filters, first stage aeration,
2 intermediate clarifiers, second stage aeration, 2 final clarifiers, aerated polishing
pond, 4 anaerobic sludge digesters, and chlorination.
f. Please provide a description of proposed wastewater treatment facilities: The
proposed W WT facilities consist of a coarse mechanical bar screen, influent pumping
station, 2 fine mechanical bar screens, 2 aerated grit removal chambers, 3 primary
clarifiers, 2 trickling filters (optional operation), parallel BNR systems consisting of
oxic and anoxic stages as well as an anaerobic basin each, 3 aeration basins for
additional aeration capacity, 2 final clarifiers, denitrification effluent filters, UV
disinfection, cascade reaeration, gravity belt thickening, 4 anaerobic sludge digesters,
and sand drying beds.
The Phase two modifications will include various flow splitting and bypass
capabilities.
g. Possible toxic impacts to surface waters: This facility has a history of compliance
with toxicity testing.
h. Pretreatment Program (POTWs only): The CMUD has an approved pretreatment
program. There are 3 significant industrial users permitted to discharge process
wastewater to the- W WTP. None of these industrial users are textile manufacturers
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nor do they add any dyes that would affect the proposed UV sterilization process.
2. • Residuals handling and utilization/disposal scheme: Residuals treatment consists of four
anaerobic digesters, sludge drying beds, and land application.
a. If residuals are being land applied, please specify DEM permit no.: WQ0000057
Residuals Contractor: Bio Gro, Inc. Telephone No.: [phone]
b. Residuals stabilization: PSRP
3. Treatment plant classification: Class IV (rating will not change as a result of the proposed
expansion).
4. SIC Code(s): 4952
Wastewater Code(s): 01
Main Treatment Unit Code: 11503
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant funds or are any public monies
involved (municipals only)? The proposed WWTP modifications will be funded with public
monies.
2. Special monitoring or limitations (including toxicity) requests: Effluent limitation changes
should be implemented with the increase in design capacity. No additional monitoring and/or
limitations are recommended at this time.
3. Important SOC, JOC or Compliance Schedule dates (Please indicate): N/A
4. Alternative Analysis Evaluation: N/A
PART IV - EVALUATION AND RECOMMENDATIONS
The proposed facility contains a plan for BNR and BPR. This should result in lower nitrates
and phosphates in the effluent. Also, the parallel flow scheme should be more resistant to upset and
provide more flexibility.
On page 22 of the Engineering Design Report there is a section entitled "Bypass Line". The
bypass capability mentioned appears to be for flexibility only.
This office recommends granting the authorization to construct.
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Signature of aport preparer D to
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Water Quality Re ' nal Supervisor Date
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