NC0036277_Permit Issuance_20010309

NPDES DOCYNENT SCANNINO COVER SMEET
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:
March 9, 2001
This document is printed on reuse paper - igraore aazy
content on the reverse side

of w A rF9
b `o� Q� Q��
> r NCDENR
o c
Mr. Barry Gullet
CMUD Administrative Division
5100 Brookshire Boulevard
Charlotte, North Carolina 28216
Dear Mr. Gullet:
Michael F. Easley
Governor
William G. Ross, Jr., Secretary
North Carolina Department of Environment and Natural Resources
Kerr T. Stevens, Director
Division of Water Quality
March 9, 2001
Subject: Issuance of NPDES Permit NCO036277
CMUD McDowell Creek WWTP
Mecklenburg County
Division of Water Quality (Division) personnel have reviewed and approved your application for renewal of
the subject permit. Accordingly, we are forwarding the attached NPDES discharge permit. This permit is issued
pursuant to the requirements of North Carolina General Statute 143-215.1 and the Memorandum of Agreement
between North Carolina and the U.S. Environmental Protection Agency dated May 9, 1994 (or as subsequently
amended).
The following changes have been made to your permit:
• The cover letter to your facility's draft permit erroneously stated that the new effluent mercury limit
would be 0.14 µg/L. The effluent limit is, as listed in the effluent limits page of the draft, 0.014 jig/L.
• The June -September frequency for instream dissolved o:rygen, temperature, conductivity and pH
monitoring has becn changed to once per week as per your request.
• The last line to the cyanide footnote in the effluent limits page has been deleted. You are no longer
required to report values of cyanide measured below the specified quantitation 'level. A value of less than
10 µg/L will be considered zero for compliance purposes. Additionally, you should consider adherence
to the quantitation level of 10 µg/L for cyanide and 0.2 µg/L for mercury as fulfilling the intent of Part
II Section D. (4) of the NPDES permit for utilization of the most sensitive laboratory methods possible.
By transmittal of this letter, these quantitation limits apply to all NPDES permits for the CMUD
wastewater treatment plants.
• As per a conference call made on December 21, 2000 between members of the NPDES Unit and your
staff, the reasonable potential analysis for nickel was re -run using data from June 1999 onward. The
results of this analysis indicate that there is no need for a nickel limit. You will still be required to
monitor nickel through the Pretreatment Long Term Monitoring Plan.
• The draft permit erroneously reported your total residual chlorine (MC) limit as 22 µg/L. The limit,
based on the instream waste concentration of your effluent, should be 20 µg/L. Please note the change
on the effluent limits page.
• The instream monitoring requirements in the draft permit (Part A.(3.)) required that a spatial composite.
sample be taken for chlorophyll -a, total phosphorus, NH3-N, TILT, and NO2-NO3. Asper your request,
the sample type has been changed to grab to account for the shallow water level in the stream at the
sampling point. The Division feels that this sampling requirement will provide important information
regarding the effect of your discharge on the water quality of both the receiving stream and Mountain
Island Lake. In response to your concern over chlorophyll -a monitoring, while it is true that there is no
certification for this analysis available through the Division's Laboratory Certification Program, you are
nevertheless required to perform this monitoring.
N. C. Division of Water Quality / NPDES unit Phone: [phone]
1617 Mail Service Center, Raleigh, NC 27699-1617 fax: [phone]
Internet: h2o.enr.state.nc.us DENR Customer Service Center:1800 623-7748

The expiration date of the permit will stand at February 28, 2005, as per the draft permit. This is in
accordance with the Division's Basinwide permitting schedule. This system of issuing permits by subbasin allows the
Division to spread out the permits in basins containing many pennittees, of which the Catawba is one. In doing so,
the NPDES unit may maintain a balanced workload, regardless of the river basin.
The silver monitoring requirement in your permit is based upon a fording of reasonable potential for effluent
from your facility to violate the allowable instream silver concentration of 0.1 µg/L. A review of your facility's
Discharge Monitoring. Reports indicated five silver detects in the past two years. Once your facility has collected one
year of silver data for which there have been no detects, you may request a modification to the pen -nit that reduces or
eliminates the monitoring requirement.
In response to your query about measurement frequency, "daily" does indeed mean five days per week
excluding weekends and/or holidays. The Division is currently working on documentation to clarify this for all
NPDES permit holders. --
As mentioned in the cover letter to the draft NPDES permit, the request for a monthly maximum flow limit
of 7.6 MGD requires an Environmental Assessment (EA). The State Environmental Policy Act (SEPA) requires all
facilities utilizing public monies to submit an EA for any expansions to ensure that the increased flow will not have a
detrimental effect on the stream. Your request is functionally equivalent to an expansion, and so falls under the
legislative requirements of SEPA.
If any parts, measurement frequencies or sampling requirements contained in this permit are unacceptable to
you, you have the right to an adjudicatory hearing upon written request within thirty (30) days following receipt of
this letter. This request must be in the form of a written petition, conforming to Chapter 150B of the North Carolina
General Statutes, and filed with the Office of Administrative Hearings (6714 Mail Service Center, Raleigh, North
Carolina 27699-6714). Unless such demand is made, this decision shall be final and binding.
Please note that this pemvt is not transferable except after notice to the Division. The Division may require
modification or revocation and reissuance of the permit. This permit does not affect the legal requirements to obtain
other permits which may be required by the Division of Water Quality or permits required by the Division of Land
Resources, the Coastal Area Management Act or any other Federal or Local governmental permit that may be
required.
If you have any questions concerning this permit, please contact Natalie Sierra at telephone number (919)
733-5083, extension 551.
Sincerely,
ORIGINAL, 810FI 3Y
ULL IREIC
Kerr T. Stevens
Cr- Mooresville Regional Office/Water Quality Section
Mr. Roosevelt Childress, EPA
Mecklenburg County Health Department
Aquatic Toxicology Unit
NPDES Unit
Central Files
NC Department of Environmental Health

Permit NCO036277
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful
standards and regulations promulgated and adopted by the North Carolina Environmental
Management Commission, and the Federal Water Pollution Control Act, as amended,
Charlotte -Mecklenburg Utility Department
is hereby authorized to discharge wastewater from a facility located at the
McDowell Creek Wastewater Treatment Plant
NCSR 2074
Near the Town of Huntersville
Mecklenburg County
to receiving waters designated as McDowell Creek in the Catawba River Basin
in accordance with effluent limitations, monitoring requirements, and other
conditions set forth in Parts I, II, III and IV hereof.
This permit shall become effective April 1, 2001.
This permit and authorization to discharge shall expire at midnight on February 28, 2005.
Signed this day March 9, 2001.
C)RIGIKAL SIGNED BY
BOLL REID
Kerr T. Stevens, Director
Division of Water Quality
By Authority of the Environmental Management Commission

Permit NC0036277
la
SUPPLEMENT TO PERMIT COVER SHEET
Charlotte -Mecklenburg Utility Department is hereby authorized to:
y
1. Continue to operate the existing 6.0 MGD wastewater treatment facility
consisting of:
• Mechanical bar screens
• grit removal
• primary clarifiers --
• Biological Nutrient Removal (BNR) system
• tertiary filtration
• final clarifiers
• anaerobic sludge digestion
• sand drying beds
• UV disinfection
located at McDowell Creek Wastewater Treatment Plant, on SR 2074, Neck
Road, near the Town of Huntersville in Mecklenburg County
2. Discharge from said treatment works at the location specified on the attached
map into McDowell Creek, which is classified WS-IV waters in the Catawba River
Basin.

NC00036277
- CMUD McDowell Creek
Facility 1
Latitude:
35°22'52" Sub -Basin: 03-08-33
Location
Longitude:
80°56'25"
uad N:
FISNW/Lake Norman South
Stream Class:
Receiving Stream:
WS-Iv
McDowell Creek
/
Charlotte Mecklenburg Utilities Department (CMUD)
NCa03627,
Permitted Flow:
6.0 MGD
CMUD - McDowell Creek W WTP

Permit N 0036177
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS -
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 001. Such discharges shall be limited and monitored by the Permittee as
specified below:
EFFLUENT N S, � ` r ¢;=�F,.
L-. �i' �^
.+�':'•�,l'tn «F arti lr � its �he�6^;yii
CHARACTERISTICS l•.
�.� LIMITS f *r ��
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i =. a -. r e... �.�; 1.
.a �: � MONI ORINGGREQUIREMENTS,,�� T=x
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Avee
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Same
SamIeLoca
�Mont
oti
Flow
6.0 MGD
Continuous
Recording
I or E
BOD5 (20°C)2
April 1- October 31
5.0 mg/L
7.5 mg1L
Daily
Composite
E,
BOD5 (20°C)2
November 1- March 31
10.0 mg/L
15.0 mg/L
Daily
Composite
E,
Total Suspended Residue2
30.0 m /L
45.0 m /L
Daily
Composite
E, I
NH3 as N (April 1— October 31
2.0 m /L
Daily
Composite
E
NH3 as N November 1—March 31
2.5 m /L
Daily
Composite
E
Dissolved Oxygen3
Daily
Grab
E, U, D
Fecal Coliform
(geometric mean
2001100 ml
400 / 100 ml
Daily
Grab
E
Total Residual Chlorine4
20 /L
Daily
Grab
E
Temperature °C
Daily
Grab
E, U, D
Total Nitrogen NO2 + NO3 + TKN
10.0 m IL
Monthly
Composite
E
Total Phosphorus
1.0 m /L
Monthly
Composite
E
Chronic Toxicitys
Quarterly
Composite
E
Conductivity
Daily
Grab
E, U, D
Copper
2/Month
Composite
E
Silver
2/Month
Composite
E
Zinc
2/Month
Composite
E
Mercury6
0.014 /L
Weekly
Composite
E
Footnotes:
1 Sample Locations: E - Effluent, I - Influent, U - Upstream at Beatties Ford Road, D- Downstream at
Neck Road. Upstream and downstream samples shall be grab samples. Stream samples shall be
taken once per week.
2 The monthly average effluent BOD5 and total suspended residue concentrations shall not exceed
15% of the respective influent value (85% removal).
3 The daily average dissolved oxygen effluent concentrations shall' not be less than 5.0 mg/ L.
4 Limit and monitoring only apply if effluent is chlorinated.
S Whole effluent toxicity shall be measured by Chronic Toxicity (Ceriodaphnia) P/ F at 85 %. Samples
shall be collected quarterly during the months of January, April, July and October. See Part A.(2.).
6 The quantitation limit for mercury shall be 0.2 ug/1 (0.2 ppb). Levels reported as less than 0.2 ug/1
shall be considered zero for compliance purposes.
The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Instream monitoring shall be in accord with the requirements specified in Part
A.(3.), "Instream Monitoring Requirements."

. Permit NCO036277
A. (2.) CHRONIC TOXICITY PERMIT LIMIT
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant
mortality to Ceriodaphnia dubia at an effluent concentration of 85%.
The permit holder shall perform at a minimum, Quarterly monitoring using test procedures
outlined in the "North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised
February 1998, or subsequent versions or "North Carolina Phase II Chronic Whole Effluent
Toxicity Test Procedure" (Revised -February 1998) or subsequent versions. The tests will be
performed duri#g the months of January, April, July and October. Effluent sampling for this
testing shall be performed at the NPDES permitted final effluent discharge below all treatment
processes.
If the test procedure performed as the first test of any single quarter results in a failure or ChV
below the permit limit, then multiple -concentration testing shall be performed at a minimum,
in each of the two following months ds described in "North Carolina Phase II Chronic Whole
Effluent Toxicity Test Procedure" (Revised -February 1998) or subsequent versions.
The chronic value for multiple concentration tests will be determined using the geometric mean of the
highest concentration having no detectable impairment of reproduction or survival and the lowest
concentration that does have a detectable impairment of reproduction or survival. The definition of
"detectable impairment," collection methods, exposure regimes, and further statistical methods are
specified in the "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -
February 1998) or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered on the Effluent
Discharge Monitoring Form (MR-1) for the months in which tests were performed, using the
parameter code TGP3B for the pass/fail results and THP3B for the Chronic Value. Additionally, DWQ
Form AT-3 (original) is to be sent to the following address:
Attention: North Carolina Division of Water Quality
Environmental Sciences Branch
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Branch no
later than 30 days after the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/physical measurements and
all concentration/response data, and be certified by laboratory supervisor and ORC or approved
designate signature. Total residual chlorine of the effluent toxicity sample must be measured and
reported if chlorine is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is
required, the permittee will complete the information located at the top of the aquatic toxicity (AT)
test form indicating the facility name, permit number, pipe number, county, and the month/year of
the report with the notation of ",No Flow" in the comment area of the form. The report shall be
submitted to the Environmental Sciences Branch at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required,
monitoring will be required during the following month.
Should any test data from this monitoring requirement or tests performed by the North Carolina
Division of Water Quality indicate potential impacts to the receiving stream, this permit may be re-
opened and modified to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum
control organism survival, minimum control organism reproduction, and appropriate environmental
controls, shall constitute an invalid test and will require immediate follow-up testing to be completed
no later than the last day of the month following the month of the initial monitoring.

Permit NCO036177
A.(3.) INSTREAM MONITORING REQUIREMENTS
a
In addition to the stream monitoring requirements specified in Part A. (1.), the permittee must
monitor for the following between the months of April - October.
Parameter
Frequency/Type
Location
Chlorophyll -a
Monthly/grab
Downstream at Neck Road
Total Phosphorus
Monthly/grab
Downstream at Neck Road
NH3-N
Monthly/grab
Downstream at Neck Road
TKN
Monthly/grab
Downstream at Neck Road
NO2-NO3
Monthly/grab
Downstream at Neck Road

January 10. 2001
•
CUt TL
Ms. Natalie V. Sierra
NCDENR — DWQ — NPDES Unit
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: McDowell Creek WWTP Permit Renewal
NPDES Permit No. NCO036277
Dear Ms. Sierra:
ui
JAN 12 ?A01 �J
I DEN R - WATER QUALITY
POIi1T SOURCE BRANCH
This is in response to your letter dated December 6, 2000, and received on December
12, 2000, concerning the renewal of the subject NPDES Permit. As directed by your
letter, we are transmitting our comments within 30 days of our receipt of the letter and
draft permit.
We agree with your conclusions about cadmium, lead, and cyanide and concur
with the removal of permit limits for these parameters.
The cover letter states that the daily maximum limit for mercury will be 0.14 pg/I
and the draft permit states it will be 0.0�14 a/I. Please clarify which is correct.
3. The draft permit includes increased instream monitoring requirements for
chlorophyll -a, total phosphorus, NH3-N, TKN, and NO2-NO3 at Neck Road. At that
\n point, the stream is very shallow and it is expected to be difficult to collect a
rt(W" spatial composite sample (please confirm that composite in this instance does not
Jmean a time composite). We also understand that there is no certification for
chlorophyll -a analysis available through the NCDENR Laboratory ertification
Program. Lzp-)1 3- 5&� (may�� _A
Please note also that Mecklenburg County Department of Environmental Lo
Protection (MCDEP) routinely conducts both stream and lake sampling across the
county. Their routine sites include McDowell Creek at Neck Road and at Beatties
Ford Road (upstream of the WWTP) and a lake site in McDowell Cove of
Mountain Island Lake. Their routine sampling at the lake site includes chlorophyll -
a, total phosphorus, NH3-N, TKN, nitrates and nitrites, secchi disk, and a number
of other parameters. Their present sampling schedule is monthly except
February, April, October, and December.
MCDEP is also conducting an intensive sampling program to support
development of a very detailed water quality model for the McDowell basin.
Administration Division 5100 Brookshire Blvd. Charlotte, NC 28216 Phone: [phone] Fax: [phone]
Charlotte -Mecklenburg Utilities

We believe that the sampling and modeling conducted by MCDEP and the data
base that they maintain would be adequate and available for DENR needs and
request that section A.(3) be removed from the permit.
4. til
It is requested that sampling frequency for in -stream samples other than those in
section A.(3.) be reduced from three times per week during summer months to
e
once per week.
Please revise the language concerning cyanide and mercury testing and reporting
to reflect the discussions we have had about the same issues relative to the
McAlpine Creek Permit. Specifically, the revision would recognize quantitation
limits of 10 pg/I and 0.2 pg/I for cyanide and mercury respectively and would not
require reporting numeric values less than these levels. Also, please confirm that
laboratory methods using these quantitation levels will fulfill all permit
covev-
requirements and, that for all parameters, compliance with NCDENR Laboratory
Certification Regulations meets the requirements for "adequate laboratory controls
and appropriate quality assurance procedures."
The draft permit adds a new monitoring requirement for silver. We have routinely
sampled for this parameter for several years as part of our headworks analysis
and have not detected any. Although we plan to continue to monitor for
headworks purposes, we request that the twice per month sampling requirement
be deleted from the permit. 5 , vG e - a, i 0') rS . lure
7. In our application for renewal, we requested that the permit allow a maximum
monthly treatment rate of 7.6 mgd and an annual average daily rate of 6.0 mgd to
recognize the design criteria and capabilities of the plant. Your letter states that
an environmental assessment would be required to make this change. Please
note that we are currently planning and designing an expansion of McDowell
Creek. The permit requested for the expanse n and associated EA may request
an interim rating based on this criteria. j�p�2o �j t;m 4� .�
Notwithstanding basin -wide permitting schedules and our anticipated request for
an expansion permit, we request that the permit be issued for a full five year tet
rather than the proposed approximately four year period. tb . vvJu Voe.
zt,C t IEOUA
The plant description in the draft permit includes sludge thickening. Gravity belt
sludge thickeners are under construction at this time but are not yet in-service.
10. It appears that we may have received the incorrect "boilerplate" sections for the
McDowell Creek Permit. Particularly, Part I Section B and Part III would not �,..
appear to apply. If the corrected versions are different than those last issued, we '
request additional time to review and comment.

11. Please clarify that "daily" in the "Measurement Frequency" column of Section
A.(1.) means five days per week excluding weekends and/or holidays." `AIL
12. We have discussed the proposed nickel limit by phone recently and have /
submitted additional relevant information. Please review this additional
information to determine if the nickel limit is necessary.
Please let me know if you have any questions or need additional information. If you
would like, we would be glad to meet with you to discuss any outstanding issues.
Sincerely,
CHARLOTTE MEJ)�(
CKLLEENBURG UTILITIES
r� d
Barry M,� Gullet, PE
Deputy Director
C: Jackie Jarrell
Pete Goins
Myra Zabec
Dawn Padgett
Dave Goodrich
Rex Gleason
File

- �e
North Carolina } as
Mecklenburg County}
NCDENR/DWQ/BUDGET OFFICE
ACCOUNTS PAYABLE
1617 MAIL SERVICE CENTER
RALEIGH NC 27699-1617
The Knight Publishing Co., Inc.
Charlotte, NC
Affidavit of Publication
THE CHARLOTTE OBSERVER
+------------- -------
REFERENCE: 30019881
3917854 NPDES WASTEWARTER PE
Before the undersigned, a Notary Public of said
County and State, duly authorized to administer
oaths affirmations, etc., personally appeared,
being duly sworn or affirmed according to law,
doth depose and say that he/she is a
representative of the Knight Publishing Company a
corporation organized and doing business under the
laws of the State of Delaware, and publishing a
newspaper known as The Charlotte Observer in the
city of Charlotte, County of Mecklenburg and State
of North Carolina and that as such he/she is
familiar with the books, records, files and
business of said Corporation and by reference to
the files of said publication
the attached advertisement was inserted. The
following is correctly copied from the books and
files of the aforesaid Corporation and
Publication.
PUBLISHED ON: 11/14
PUBLIC NOTICE
STATE OF NORTH CANOLINA
ENVIRONMENTAL MANAGEMENT COMMISSIONINPOE9 UNIT
1617 MAIL SERVICE CENTER
RALEIGH, NC Y16941647
NOTIFICATION OF INTENT TO ISSUE A NPOES WAS EE AATCRER PER BIT
AD SPACE: 100 LINE
FILED ON: ll/15/001
------- -------' -- --------------j/ } 7----------------------
NAME: �....... ,(„-41:-x. I L 4L'"� TITLE • / tC. / L�:eY
/%,-.
In Testimony Whereof I have hereunto set my hand and affixed my seal, the
day and N
aforesaid.
Notary: ) Commission Expires://

Vo.16f
DENR/DWQ
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NCO036277
Facility Information
Applicant/Facility Name:
Charlotte -Mecklenburg Utilities Department (CMUD) — McDowell
Creek WWTP
Applicant Address:
5100 Brookshire Blvd.; Charlotte, NC 28216
Facility Address:
NCSR 2074, near the Town of Huntersville
Permitted Flow
6.0 MGD
Type of Waste:
85% Domestic
15% Industrial
Facility/Permit Status:
Class IV/Active; Renewal
County:
Mecklenburg County
Miscellaneous
Receiving Stream:
McDowell Creek
Regional Office:
Mooresville
Stream Classification:
WS-IV
State Grid / USGS Quad:
F15NW/Lake
Norman
303 d Listed?
Yes
Permit Writer:
Natalie Sierra
Subbasin:
03-08-33
Date:
7November00
Drainage Area (mi):
28.3
^
Lat. 35022 52" N Long. 80° 56' 25" W
Summer 7Q10 (cfs)
1.8
Winter 7Q10 (cfs):
4.2
30Q2 cfs
Average Flow cfs):
31
IWC (%):
85
�
BACKGROUND !???
McDowell Creek WWTP is one of the five Charlotte -Mecklenburg Utilities Department
(CMUD) plants, regently expanded to a total design flow of 6.0 MGD. The facility serves the
Town of Huntersv je, Town of Davidson, Town of Cornelius, and unincorporated areas of
Mecklenburg County. In addition, the plant also accepts wastewater from 3 significant industrial
users (SIUs) and as such, has a full Long Term Monitoring Program (LTMP) with the
Pretreatment program.
At the time of the last permit renewal, the facility had applied for an Authorization to
Construct (ATC) that would allow for a plant expansion to 6.0 MGD along with other capital
improvements. The 1995 permit was therefore a phased permit, setting limits for 3.0 MGD,
interim flow of 3.5 MGD and the final 6.0-MGD flow. Construction on the plant expansion was
completed in April 1999 and includes improvements to the headworks and the residuals
management portions of the plant.
Instream Monitoring and Verification of Existing Conditions and DMR Data Review.
DMRs were reviewed beginning in January 1999 through August 2000. This period of
time was selected since expansion was near finished at the beginning of 1999. Average flow
during this time was 4.3 MGD.
Dissolved Oxygen and Total Phosphorus instream data were analyzed for the permit
renewal. Between Jan 1999 and August 2000, the dissolved oxygen (DO) values downstream of
the discharge were above 6 mg/L on all but 5 summer sampling days. Downstream DO values
were always above 5 mg/L both upstream and downstream of the discharge. Both upstream and
Fact S,wl
NPDES N00036277 Rcncwol
Pagc I

downstream DO measurements were below the saturation DO value for the measured
temperatures. The average DO drop from upstream to downstream was 1.4 mg/L. Please see the
attached plot of DO stream data for more information.
Instream phosphorus data downstream of the discharge were also analyzed. Among 80
samples, 60 measured total phosphorus values below 0.1 mg/L. The remaining sampling points
measured total phosphorus values at or below 1.0 mg/L. Low phosphorus loads are important
given the close proximity to Mountain Island Lake downstream.
CMUD-McDowell Creek monitors for a broad range of metals due to the large industrial
contribution to its wastestream. Data from both the Pretreatment LTMP and the DMRs were
used to assess reasonable potential for arsenic, cadmium, chromium, lead, copper, nickel, silver,
zinc, cyanide, mercury, molybdenum, and selenium.
Results of Reasonable Potential Analysis (RPA):
A reasonable potential analysis (RPA) was performed for all monitored parameters. It
was determined that there is reasonable potential for violations of instream standards of the
following:
• Copper
• Nickel
• Silver
• Zinc
• Mercury
No reasonable potential exists for the following:
• Arsenic
• Cadmium
• Chromium \
• Lead
• Cyanide
• Molybdenum
• Selenium
Copper, Silver, and zinc are all action level pollutants. Since CMUD —McDowell does
not currently have toxicity problems, these compounds will be monitored only, not
limited. The current NPDES permit does not limit nickel, so a limit will be added.
Correspondence: The inspection reports generally reveal a well -run facility with few problems.
There have been, however, several NOVs issued per year. The bulk of these have been for flow
exceedences. The facility had one toxicity violation in 1999, but none since completion of the
expansion.
PERMITTING STRATEGY AND SUMMARY OF PROPOSED CHANGES
The most recent basin plan for the Catawba River (December 1999) discusses the
contribution of McDowell Creek WWTP to downstream impairment of both McDowell Creek
and Mountain Island Lake. Nutrient loading upstream of Mountain Island Lake has been
responsible for a eutrophic response in this lake. It is hoped that the recent improvements to
McDowell Creek will reduce phosphorus loadings to the lake.
Pact Sheet
NPI)ES NCO036277 Renewal
Page 2

Due to finding of reasonable potential, mercury and nickel will be limited in the NPDES
permit. Cadmium, lead, and cyanide limits and monitoring will be eliminated from the NPDES
permit, though they will continue to be monitored by the Pretreatment program.
All the other parameters will remain the same in accordance with the previous permit and
1995 WLA. In that (as well as the current) permit, BOD, Total Suspended Residue, Total
Nitrogen, fecal coliform, Total Phosphorus and mercury were all water quality limited
parameters. We may wish to include upstream/downstream nutrient monitoring to assess the
impact of the discharge on the receiving stream. CMUD-McDowell performs considerably less
instream monitoring than McAlpine, Irwin, and Sugar Creek W WTPs.
Pact Sheet
NPDES NC0036277 Renewal
Page 3

PROPOSED SCHEDULE FOR PERMIT ISSUANCE
Draft Permit to Public Notice:
Permit Scheduled to Issue:
NPDES DIVISION CONTACT
December 13, 2000
January 29, 2001
If you have questions regarding any of the above information or on the attached permit, please contact
Natalie Sierra at [phone] ext. 551.
NAME: DATE:
REGIONAL OFFICE COMMENTS
,fP/`2R-' i o /Ic o 3 6 Z X2 /1 c c S vBn�/7c�i� o -v M/3�j1 / 9'
,9— SA411� W 77G L /!/i% SG -� O O� ZZjt"�/^' - -- %q`G?S&-
conif-�R/�
3 - cjAt t D6 /s A4i G�N,Tt�� /%u�/fy /s
— �/n/.4L C�4�/Hir� S �R� L/s% �, �IG � a '� .✓ %f� /
DATE: /—/ 7/ -
Fact Sheet
NPI)LS N00036277 Renewal
Page 4

REASONABLE POTENTIAL ANALYSIS
Prepared by: Natalie Sierra, 11/7/00
Facility Name =
NPDES # _
Qw (MGD) _
Qw (cfs) =
7Q90s (cfs)=
/WC (%) _
CMUD-McDowell Creek
NC0036277
6
9.2832
1.8
83.78
Chronic CCC w/s7Q10 dil.
Acute CMC w/no dil.
Frequency of Detection
Parameter
FINAL RESULTS, ug/I
FINAL RESULTS, ug/I
#Samples
# Detects
Arsenic
Max. Pred Cw
3.8
Allowable Cw
59.7
360
40
0
Cadmium
Max. Pred Cw
1.1
Allowable Cw
2.4
15
83
2
Chromium
Max. Pred Cw
30.9
Allowable Cw
59.7
1022
80
6
Lead
Max. Pred Cw
19.2
Allowable Cw
29.8
34
81
7
Copper (A.L.)
Max. Pred Cw
87.2
Allowable Cw
8.4
7.3
81
68
Nickel
Max. Pred Cw
41.1
Allowable Cw
105.0
261
58
31
Silver (A.L.)
Max. Pred Cw
26.7
Allowable Cw
0.1
1.2
81
5
Zinc (A.L.)
Max. Pred Cw
262.3
Allowable Cw
59.7
67
81
77
Cyanide
Max. Pred Cw
4.3
Allowable Cw
6.0
22
75
5
Mercury
Max. Pred Cw
1.5
Allowable Cw
0.014
NA
42
3
Molybdenum
Max. Pred Cw
27.6
Allowable Cw
NA
NA
41
8
Selenium
Max. Pred Cw
3.8
Allowable Cw
6.0
20
41
1
Modified Data: Use 0.5 Detection Limit for non -detects

nickel concentrations at McDowell
Subject: nickel concentrations at McDowell
Date: Thu, 4 Jan 2001 08:47:42 -0500
From: "Padgett, Dawn" <[e-mail]>
To: "'[e-mail]"' <[e-mail]>
CC: "Jarrell, Jackie" <[e-mail]>, "Gullet, Barry" <[e-mail]>,
"Zabec, Myra" <[e-mail]>, "Goins, Pete" <[e-mail]>
Ms. Sierra, As we discussed in the phone conference 12/21, I have put
together a letter of explanation about the high nickel results that may be
biasing the RPA. I have the letter attached to this e-mail. The letter
will also go out in the mail today. I believe that the rest of our comments
on the proposed McDowell Creek Permit will go out at the beginning of next
week.
Thanks for you help with this,
Dawn Padgett
704.391.5162 <<mcdowellnickel.doc>>
Name: mcdowellnickel.doc
Fimcdowellnickel.doc Type: Microsoft Word Document (application/msword)
Encoding: base64
Download Status: Not downloaded with message
1 of 1 1 /4/01 1:23 PM

•
CHARLOITE
January 4, 2001
Ms. Natalie Sierra
NCDENR-DWQ-NPDES Unit
1617 Mail Center Drive
Raleigh, NC 27699-1617
Dear Ms. Sierra,
i JAN 11 2001 v.
DENR - WA.ER QUALITY
POINT SOURCE BRA.HCN
As discussed in the conference call with you and Dave Goodrich last Wednesday 12/21/00, the nickel
1 PA done by you for McDowei: Creek W ffrP, NPvES Permit #NC0336277 may be biased due to
analytical difficulties. Prior to 7/1/99, nickel analyses were conducted on an Atomic Absorption
Spectrophotometer using flame ionization. The detection limit for that analytical method was 30ug/I,
but there was significant background noise present at that detection limit, causing a potential for false
positives. In July 1999, the analytical methodology was changed to the graphite furnace; which
lowered the reportable detection limit to 5ug/I. Between July *1999 and February 2000, nickel was
detected only 5 times. During that period, nickel was analyzed on a weekly basis and the highest
detected nickel concentration was 19ug/l, on 9/27199.
Since March 2000, the metals for the treatment plants have been analyzed using an ICP/MS. The
new detection limit is Zug/I and nickel has been routinely detected in the effluent of the wastewater at
very low levels. The highest detected concentration was 12ug/I on May 8, 2000. With the exception
of a 5.7ug/I result, reported for May 30, 2000, all other detectable concentrations of nickel have been
under 5ug/I. As you can see from these results, the amount of nickel in the effluent discharge from
McDowell Creek WWTP is negligible.
If you have any questions about this information, please give me a call at 704.391.5162, or you may
e-mail me at dpadgett(a)ci.charlotte.nc.us. Thank you for your assistance.
Respectfully,
4 K/cq�7�
Dawn K. Padgett
Environmental Management Division
Cc: JJarrell
BGullet
MZabec
PGoins
Administrative Division 5100 Brookshire Blvd. Charlotte, NC 28216 Phone: [phone] Fax: [phone]
Charlotte -Mecklenburg Utilities

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
December 8, 2000
MEMORANDUM
A ::
i� j
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
{v.t: vzeb. uk.
ua VIW14MENT, HEAL' Tli
• NATURAL RIBBWRGES
To: Britt Setzer 15
NC DENR / DEH / Regional Engineer
Mooresville Regional Office 9l109ilY�TAI YANA6�Fn
+nnI1E91QtE @FAIflB@J '�+
From: Natalie Sierra
NPDES Uni _
Subject: Review of Draft NPDES Permit NCO056277 I i
CMUD McDowell Creek WWTP DEC 28 2000 =�
Mecklenburg County
Please indicate below your agency's position or viewpoint on the draft permit and returq AilssfUh7SmEI�E A
January 8, 2000. If you have any questions on the draft permit, please contact me at the telephone
number or e-mail address listed at the bottom of this page.
RESPONSE: (Check one)
Concur with the issuance of this permit provided the facility is operated and maintained properly, the
stated effluent limits are met prior to discharge, and the discharge does not contravene the designated
water quality standards.
❑ Concurs with issuance of the above permit, provided the following conditions are met:
❑ Opposes the issuance of the above permit, based on reasons stated below, or attached:
1617 Mail Service Center, Raleigh, North Carolina 27699-1617 919 733-5083, extension 538 (fax) 919 733-0719
Vlsn us ON THE INTERNET@ httpYth2o.encstate.nc.us/NPDES Christie.Jackson@ ncmail.nel

DENR/DWQ
• FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NCO036277
Facility Information
pp ican aci ityName:
Charlotte -Mecklenburg Utilities Department — McDowell
Creek WWTP
ApplicantAddress:
5 100 Brookshire Blvd.; Charlotte, NC 28216
FacilityAddress:
NCSR 2074, near the Iown of Huntersville
Permitted ow
7T MUD
Type of Waite:
o Domestic
15% Industrial
Facility/PermitStatus:
ClassIV/Active; Renewal
ounty:
Mecklenburg County
Miscellaneous
Receiving tream:
McDowell CreekRegional
ice:
Mooresville
tream Classification:
WSAV
State rid Quad:
a e
Norman
tste
es
PermitWriter:
Natalie Sierra
u asin:
- -
ate:
r7NovemberOO
Drainage Area (mi ):
28.3
gx ��
Lat. 350 22 52" N Long. 80° 56' 25" W
Summer c s'
Winter c s
cs
verageFlow c s :
IWC° '
BACKGROUND
McDowell Creek WWTP is one of the five Charlotte -Mecklenburg Utilities Department
(CMUD) plants, recently expanded to a total design flow of 6.0 MGD. The facility serves the
Town of Huntersville, Town of Davidson, Town of Cornelius, and unincorporated areas of
Mecklenburg County. In addition, the plant also accepts wastewater from 3 significant industrial
users (SIUs) and as such, has a full Long Term Monitoring Program (LTMP) with the
Pretreatment program.
At the time of the last permit renewal, the facility had applied for an Authorization to
Construct (ATC) that would allow for a plant expansion to 6.0 MGD along with other capital
improvements. The 1995 permit was therefore a phased permit, setting limits for 3.0 MGD,
interim flow of 3.5 MGD and the final 6.0-MGD flow. Construction on the plant expansion was
completed in April 1999 and includes improvements to the headworks and the residuals
management portions of the plant.
Instream Monitoring and Verification of Existing Conditions and DMR Data Review.
DMRs were reviewed beginning in January 1999 through August 2000. This period of
time was selected since expansion was near finished at the beginning of 1999. Average flow
during this time was 4.3 MGD.
Dissolved Oxygen and Total Phosphorus instream data were analyzed for the permit
renewal. Between Jan 1999 and August 2000, the dissolved oxygen (DO) values downstream of
the discharge were above 6 mg/L on all but 5 summer sampling days. Downstream DO values
were always above 5 mg/L both upstream and downstream of the discharge. Both upstream and
downstream DO measurements were below the saturation DO value for the measured
temperatures. The average DO drop from upstream to downstream was 1.4 mg/L. Please see the
attached plot of DO stream data for more information.
Instream phosphorus data downstream of the discharge were also analyzed. Among 80
samples, 60 measured total phosphorus values below 0.1 mg/L. The remaining sampling points
measured total phosphorus values at or below 1.0 mg/L. Low phosphorus loads are important
given the close proximity to Mountain Island Lake downstream.
Fact Sheet
NPDES NCO036277 Renewal
Page 1

• ' CMUD-McDowell Creek monitors for a broad range of metals due to the large industrial
contribution to its wastestream. Data from both the Pretreatment LTMP and the DMRs were
used to assess reasonable potential for arsenic, cadmium, chromium, lead, copper, nickel, silver,
zinc, cyanide, mercury, molybdenum, and selenium.
Results of Reasonable Potential Analysis (RPA):
A reasonable potential analysis (RPA) was performed for all monitored parameters. It
was determined that there is reasonable potential for violations of instream standards of the
following:
• Copper
• Nickel
• Silver
• Zinc
• Mercury
No reasonable potential exists for the following:
• Arsenic
• Cadmium
• Chromium
• Lead
• Cyanide
• Molybdenum
• Selenium
Copper, Silver, and zinc are all action level pollutants. Since CMUD —McDowell does
not currently have toxicity problems, these compounds will be monitored only, not
limited. The current NPDES permit does not limit nickel, so a limit will be added.
Correspondence: The inspection reports generally reveal a well -run facility with few problems.
There have been, however, several NOVs issued per year. The bulk of these have been for flow
exceedences. The facility had one toxicity violation in 1999, but none since completion of the
expansion.
PERMITTING STRATEGY AND SUMMARY OF PROPOSED CHANGES
e most recent basin plan for the Catawba River (December 1discusses the
contribution of McDowell Creek WWTP to downstream impairment of both McDowell Creek
and Mountain Island Lake. Nutrient loading upstream of Mountain Island Lake has been
responsible for a eutrophic response in this lake. It is hoped that the recent improvements to
McDowell Creek will reduce phosphorus loadings to the lake.
Due to finding of reasonable potential, mercury and nickel will be limited in the NPDES
permit. Cadmium, lead, and cyanide limits and monitoring will be eliminated from the NPDES
permit, though they will continue to be monitored by the Pretreatment program.
All the other parameters will remain the same in accordance with the previous permit and
1995 WLA. In that (as well as the current) permit, BOD, Total Suspended Residue, Total
Nitrogen, fecal coliform, Total Phosphorus and mercury were all water quality limited
parameters. We may wish to include upstream/downstream nutrient monitoring to assess the
impact of the discharge on the receiving stream. CMUD-McDowell performs considerably less
instream monitoring than McAlpine, Irwin, and Sugar Creek WWTPs.
Fact Sheet
NPDES NCO036277 Renewal
Page 2

PROPOSED SCHEDULE FOR PERMIT ISSUANCE
Draft Permit to Public Notice:
Permit Scheduled to Issue:
NPDES DIVISION CONTACT
December 13, 2000
January 29, 2001
If you have questions regarding any of the above information or on the attached permit, please contact
Natalie Sierra at [phone] ext. 551.
NAME:
REGIONAL OFFICE COMMENTS
NAME:
SUPERVISOR:
DATE:
DATE:
DATE:
Fact Sheet
NPDES NCO036277 Renewal
Page 3

Instream Dissolved Oxygen for McDowell Creek VOWP
16
14
12
Upstream DO
—�- Downstream DO
-�- Saturation DO
4
2
0
11 /1 /98 2/9/99 5/20/99 8/28/99 12/6/99 3/15/00 6/23/00 10/1 /00
Date
0

ov
tom`
REASONABLE POTENTIAL ANALYSIS
Prepared by: Natalie Sierra, 11/7100
Facility Name =
NPDES # _
Qw (MGD) _
Qw (cfs) _
7Q10s (cfs)=
/ WC (%) _
CMUD-McDowell Creek
NC0036277
6
9.2832
1.8
83.78
Chronic CCC w/s7Q10 dil. Acute CMC w/no dil.
Frequency of Detection
Parameter
FINAL RESULTS, ug/I FINAL RESULTS, ug/I
#Samples
# Detects
Arsenic
Max. Pred Cw
3.8
t 1
Allowable Cw
59.7
360
40
0
idJ
Cadmium
/
M�k
Max. Pred Cw
1.1
Allowable Cw
2.4
15
83
2
Chromium
Max. Pred Cw
30.9
Allowable Cw
59.7
1022
80
6
\
rGJ
Lead
��.
Max. Pred Cw
19.2
^}
Allowable Cw
29.8
34
81
7
j'
Copper (A.L.)
��
Max.ax. Pred Cw
7.2
ablePred Cw
C8.4Z IMor�H
7.3
81
68
Nickel
Max. Pred Cw
�-L`l
� 129.4
�21 MPJ
Allowable Cw
�0�' 105.0 OV-0 NG
261
75
39
Silver (A.L.)
Max. Pred Cw
26.7T*4A,MXAllowable
Cw
0.1 lo��
1.2
81
5
Zinc (A.L.)
Max. Pred Cw
262.3 �pw cT C
Allowable Cw
59.7 2 1Mo tN—kAA
67
81
77
Cyanide
Max. Pred Cw
4.3
Allowable Cw
6.0
22
75
5
Mercury
Max. Pred Cw
1.5
Allowable Cw
0.014
NA
42
3
Molybdenum
Max. Pred Cw
27.6
Allowable Cw
NA
NA
41
8
Selenium
Max. Pred Cw
3.8
Allowable Cw
6.0
20
41
1
L)" 1T
L v'rA y

Parameter = Arsenic
Standard = 50 pg/l
Dataset= DMR99
Modified Data Nondetects RESULTS
2.5 <5
Std Dev.
0.756
1 <2
Mean
1.825
1 <2
C.V.
0.414
1 <2
Sample#
40.000
1 <2
1 <2
Mult Factor =
1.530
1 <2
Max. Value
2.500 pg/I
1 <2
Max. Pred Cw
3.825 pg/l
1 <2
Allowable Cw
59.677 pg/I
1 <2
1 <2.0
1 <2
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
Parameter = Cadmium
Standard = 2 1 pg/l
Dataset= DMR99
Modified Data Nondetects RESULTS
0.3
Std Dev.
0.059
0.5 <1
Mean
0.504
0.5 <1
C.V.
0.118
0.5 <1
Sample#
83.000
0.5 <1
0.5 <1
Mult Factor =
1.118
0.5 <1
Max. Value
1.000 pg/I
0.5 <1
Max. Pred Cw
1.118 pg/l
0.5 <1
Allowable Cw
2.387 pg/l
0.5 <1
0.5 <1
0.5 <1
0.5 <1
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
1
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0
0.5 <1.0

i
Parameter = IChromium
Standard = 50 pg/l
Dataset= DMR99
ModifiedData Nondetects RESULTS
6.3
Std Dev.
4.085
15 <30
Mean
3.854
1 <2
C.V.
1.060
15 <30
Sample#
80.000
15 <30
15 <30
Mult Factor =
2.060
15 <30
Max. Value
15.000 pg/l
1 <2
Max. Pred Cw
30.900 pg/l
1 <2
Allowable Cw
59.677 pgA
15 <30
6
5
15 <30
15 <30
1 <2
1 <2
11
1 <2.0
11
1 <2
2.5 <5
2.5 <5
2.5 <5
1 <2
2.5 <5
2.5 <5
5
2.5 <5
1 <2
2.5 <5
2.5 <5
2.5 <5
1 <2
2.5 <5
2.5 <5
2.5 <5
2.5 <5
1 <2
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
1 <2.0
2.5 <5
2.5 <5
1 <2.0
2.5 <5
2.5 <5
2.5 <5
Parameter = Lead
Standard =
Dataset= DMR99
ModifiedData Nondetects RESULTS
3.6
Std Dev.
1.786
2.5 <5
Mean
2.767
1 <2
C.V.
0.646
2.5 <5
Sample#
81.000
2.5 <5
2.5 <5
Mult Factor
2.5 <5
Max. Value
11.000 pg/l
1 <2
Max. Pred Cw
19.206 pg/l
1 <2
Allowable Cw
29.839 pg/I
2.5 <5
11
5
2.5 <5
2.5 <5
1 <2
1 <2
8
2.5 <5
2.5 <5
4
2.5 <5
2.5 <5
10
2.5 <5
1 <2
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
1 <2
2.5 <5
2.5 <5
1 <2
2.5 <5
2.5 <5

O
Parameter=
Copper(A.L.)
Standard =
1
7 pg/l
Dataset= DMR99
(12/99-8/99)
ModifiedData Nondetects RESULTS
30
Std Dev.
9.289
3
Mean
11.926
15 <30
C.V.
0.779
15 <30
Sample#
81.000
15 <30
15 <30
Mult Factor =
1.779
2
Max. Value
49.000 pg/l
15 <30
Max. Pred Cw
87.171 pg/I
15 <30
Allowable Cw
8.355 pg/l
15 <30
41
41
15 <30
15 <30
7
6
49
15 <30
15 <30
6
15 <30
15 <30
40
11
8
10
5
12
16
11
6
11
5
7
4
6
3
9
11
37
7
12
8
8
10
3
6
17
8
15
3
3
Parameter = Nickel
Standard = 88d pg/l
Dataset= DMR99 12/99-4/99
ModifiedData Nondetects RESULTS
3
Std Dev.
10.843
46
Mean
6.827
<2
C.V.
1.588
36
Sample#
75.000
37
15 <30
Mult Factor
15 <30
Max. Value
50.000 pg/l
1 <2
Max. Pred Cw
129.400 pg/l
15 <30
Allowable Cw
105.032 pg/l
15 <30
4
3
48
50
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2
2.5 <5
2.5 <5
3
2.5 <5
2.5 <5
1 <2
2.5 <5
19
18
3
2.5 <5
11
2.5 <5
1 <2
2.5 <5
2.5 <5
10
2.5 <5
2.5 <5
1 <2
2.5 <5
2.5 <5
5
2.5 <5
1 <2
18
2.5 <5
1 <2
2.5 <5
2.5 <5
2.5 <5
2.5 <5

Standard = ( 0,06 J µgA
Dataset= DMR99
ModifiedDate Nondetects RESULTS
9
Std Dev.
6.330
15 <30
Mean
8.148
1 <2
C.V.
0.777
15 <30
Sample#
81.000
15 <30
15 <30
15 <30
1 <2
15 <30
15 <30
7
7
15 <30
15 <30
1 <2.0
1 <2.0
9
15 <30
15 <30
1 <2.0
15 <30
15 <30
6
15 <30
15 <30
1 <2
15 <30
15 <30
15 <30
1 <2
15 <30
15 <30
15 <30
1 <2
15 <30
15 <30
15 <30
15 <30
15 <30
1 <2
15 <30
15 <30
15 <30
1 <2
15 <30
15 <30
15 <30
1 <2
15 <30
15 <30
15 <30
15 <30
2.5 <5
1 <2.0
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.6 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
Mutt Factor = 1.777
Max. Value 15.000 µgA
Max. Pred Cw 26.655 µgA
Allowable Cw 0.072 µgA
Parameter = Zinc (A.L.)
Standard = 50 µgA
Dataset= DMR99 (12/99-111")
ModifiedData Nondetects RESULTS
97 Std Dev. 32.750
40 Mean 60.309
38 C.V. 0.543
46 Sample# 81.000
41
39
Mutt Factor
59
Max. Value
170.000
25
Max, Pred Cw
262.310
61
Allowable Cw
59.677
63
120
120
54
59
48
47
130
15 <30
40
36
36
36
170
31
37
37
15 <30
15 <30
41
62
60
48
57
45
53
58
64
67
76
71
43
87
15 <30
60
53
54
38
81
118
63
144
104
87
120
140
50
78
59
49
120
130
110
40
49
49
57
71
34
41
37
40
41
41
44
36
49
40
35
50
34
37

Parameter =
Standard =
Dataset=
ModifiedData Nondetects
1.25 <2.5
2
2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
<2
<2.0
2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2.0
1 <2.0
1 <2.0
1 <2.0
3
1 <2.0
3
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
2.5 <5
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
1 <2.0
3
1 <2.0
1 <2.0
1 <2.0
1 <2.0
3
1 <2.0
1 <2.0
1 <2.0
1 <2.0
pgA
RESULTS
Std Dev.
0.509
Mean
1.170
C.V.
0.435
Sampled
75.000
Mult Factor =
1.435
Max. Value
3.000 pg/l
Max. Pred Cw
4.305 pg/l
Allowable Cw
5.968 pg/l
Parameter =
Standard =
Dataset=
ModMedData Nondetects
0.3
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.7
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.20
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
0.1 <0.2
RESULTS
Std Dev. 0.098
Mean 0.121
C.V. 0.804
Sampled 42.000
Mult Factor = 2.200
Max. Value 0.700 pg/l
Max. Pred Cw 1.540 pg/l
Allowable Cw 0.014 pgA

s
Parameter = Molybdenum
Standard = I Ng/l
Dataset= DMR99
ModifiedData Nondetects
RESULTS
3.6
Std Dev.
3.198
5 <10
Mean
4.663
10
C.V.
0.686
5 <10
Sample#
41.000
5 <10
12
Mult Factor =
1.970
14
Max. Value
14.000 pg/l
14
Max. Pred Cw
27.580 pg/l
5 <10
Allowable Cw
0.000 Ng/l j
5 <10
5 <10
11
5 <10
5 <10
5 <10
5 <10
5 <10
5 <10
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
7.1
7
2.5 <5
2.5 <5
2.5 <5
Parameter = Selenium
Standard = 5 pg/l
Dataset= DMR99
ModifiedData Nondetects
RESULTS
0.3
Std Dev.
0.776
1 <2
Mean
1.861
1 <2
C.V.
0.417
1 <2
Sample#
41.000
1 <2
1 <2.0
Mult Factor
1 <2.0
Max. Value
2.500
1 <2.0
Max. Pred Cw
3.825
1 <2.0
Allowable Cw
5.968
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2
1 <2.0
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5
2.5 <5

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"W'.j 0'/-t/0
NPDES/Non-Discharge Permitting Unit Pretreatment Information Request Form
NPDES OR NONDISCHARGE PERMITTING UNIT COMPLETES THIS PART:
Date of Request 11 /6/00
Facility
CMUD-McDowell Creek
Permit #
NCO036277
Region
Mooresville
Requestor
Natalie Sierra
Pretreatment A D Towns- Keyes McGee (ext. 580)
Contact E-L Towns- Vacant Position
M-R Towns- Dana Folley (ext. 523)
S-Z Towns- Steve Amigone (ext 592)
PRETREATMENT UNIT COMPLETES THIS PART:
Status of Pretreatment Program (circle all that apply)
1) the facility has no SIU's and does have a Division approved Pretreatment Program that isINACTIVE
2) the facility has no SIU's and does not have a Division approved Pretreatment Program
3) the facility has (or is developing) a Pretreatment Program
a) is Full Program with or 2b) is Modified Program with STMP
4 the facility MUST develop a Pretreatment Program - Full Modified
5) additional conditions regarding Pretreatment attached or listed below
Flow
Permitted Actual v STMP time fran e•
% most recent u�A
Industrial
D • D S t7 D 2 `0
% Domestic
�q - 0next cycle
L
Pollutant
T
Check List
POC due to
M
NPDES/Non-
STMP
LTMP
Discharge
Required
Required by
Frequency at
Frequency at
P
Permit Limit
by EPA*
503 Sludge"
POC due to SIU"'
Site specific POC (Provide Explanation)••"
effluent
effluent
BOD
4
Q M
TSS
4
Q M
NH3
4
Q M
Arsenic
4
Q M
Cadmium
4
Q M
Chromium
V
4
Q M
Copper
4
Q 'M
Cyanide
4
Q M
4JILead
4
Q M
Mercury
4
Q M
Molybdemum
4
Q M
Nickel.,
4
Q M
Silver
4
Q M
Selenium
4
Q M
zinc
4
Q M
itro
4
Q M
o'
uS
4
Q M
4
Q M
4
Q M
4
Q M
4
Q M
'Always in the LTMP
"Only in the LTMP if the POTW land applies sludge
Only in LTMP while the SIU is connected to the POTW
"" Only in LTMP when the pollutant is a specific concem to the POTW (le -Chloride to a POTW who accepts Textile waste)
0= Ouarterly
M=Monthly
Comments: 5&f E M ATL FOY a eT 00% P
♦ w v-v- ".- wA- i ova .
NPDES_PIRFform.000804.As
Revised: August 4, 2000

Percent of Industrial Flow to Total Facility Flow
NPDES # of all POTW
Total Design Flow
Total Actual Flow
Industrial Flow
Treatment Plants Receiving
(Daily Average-MGD)
(Daily Average-MGD)
Recived
Industrial Wastewater
FY 2000
FY 2000
% of Actual
FY 2000
Irwin Creek - NC0034945
15
10.184
11.83%
Mallard Creek - NC0030210
8
5.587
0.20%
McAlpine Creek - NC0024970
48
40.132
5.37%
McDowell Creek - NC0036277
6
4.476
0.02%
Sugar Creek - NC0024937
20
15.253
5.78%
Industrial Users per Facility
NPDES # of Major POTW's
Number of Categorical
Number of Significant
Total
Industrial Users (CIU's)
Non -Categorical
Industrial Users
Irwin Creek- NC0034945
10
19
29
Mallard Creek - NC0030210
2
2
McAlpine Creek - NC0024970
10
30
40
McDowell Creek - NC0036277
1
1
Sugar Creek - NC0024937
11
14
25
Total
34
63
97

McDowell Creek Wastewater Treatment Plant
NPDES Permit # NCO036277
Headworks Long Term Monitoring Plan
Activated Sludge/Anaerobic Digester
with Land Application of Biosolids
A. Sampling Points (See Figure 1)
1. Influent
2. Effluent (after disinfection)
3. Primary Clarifier Influent @ DB 1
4. Primary Clarifier Effluent @ DB4
5. Final clarifier influent /Aeration Effluent @ DB9
6. Final clarifier effluent @ overflow out of final clarifier #2 (both final clarifier 1 & 2 discharge @ this
point)
7. Sludge to digester @ digester influent (hand comp/ 3 grabs per shift)
8. Sludge to drying beds or filter press @ digester effluent (hand comp/3 grabs per shift)
9. Filter Press Filtrate (hand comp/3 grabs per shift)
10. Residuals Cake, off filter press and/or sludge drying beds
11. Permitted SIU
a. There is one categorical SIU permitted to discharge to the McDowell Creek WWTP. The Charlotte -
Mecklenburg Utilities -Industrial Waste Pretreatment Program (CMU-IWPP) permit to this facility
identifies both location and frequency for monitoring.

*B. Pollutants of Concern (P.O.C.)
1. Biochemical Oxygen Demand, Chemical Oxygen Demand, Total Suspended Solids, Oil and Grease,
Ammonia -Nitrogen, Total Nitrogen (Total Kjeldahl Nitrogen and Nitrate and Nitrite), Total Phosphorus,
Arsenic, Cadmium, Chromium, Copper, Lead, Mercury, Molybdenum, Nickel, Selenium, Silver, Zinc,
Cyanide and percent solids of the sludge.
C. Flow
1. Wastewater treatment plant (as measured at the location indicated in the enclosed diagram)
2. Sludge to disposal Flow will be calculated.
D. SIU Monitoring
1. To be conducted as indicated in the permit.
a. The Permittee is required to self -monitor at least four days every three months.
b. Charlotte -Mecklenburg Utilities, System Protection Division monitors all SIU's at a minimum of four
days every quarter (i.e. Jan.- Mar., Apr. - Jun.).

'F. Sampling Frequency For P.O.C.
Sampling Point
First Three Months
Thereafter
1. Influent
Monthly for an entire 7-day week and
per NPDES requirements
Monthly on alternating days of the week and
per NPDES requirements
2. Effluent
Monthly for an entire 7-day week and
per NPDES requirements
Monthly on alternating days of the week and
per NPDES requirements
3. Primary Clarifier Influent
Monthly for an entire 7-day week
Monthly on alternating days of the week
4. Primary Clarifier Effluent
Monthly for an entire 7-day week
Monthly on alternating days of the week
5. Aeration effluent
Monthly for an entire 7-day week
Monthly on alternating days of the week
6. Final clarifier effluent
Monthly for an entire 7-day week
Monthly on alternating days of the week
7. Sludge to Digester
Monthly for and entire 7-day week and
er slud a permit and 503 regulations.
Monthly on alternating days of the week and
per sludge regulations
8. Sludge to drying beds or filter
press
Monthly for an entire 7-day week and
per sludge permit and 503 regulations
Monthly on alternating days of the week and
per sludge regulations
9. Supernate out of the anaerobic
digester or filter press filtrate
Monthly for an entire 7-day week
Monthly, on alternating days of the week
10. Residuals Cake
Monthly for an entire 7-day week and
per sludge permit and 503 regulations
Monthly on alternating days of the week and
per sludge regulations
11. Waste Activated Sludge
Monthly for an entire 7-day week
Monthly on alternating days of the week
12. SIU
Per SIU Permit
Per SIU Permit

`G. Sampling Plan
P. O. C.
Pt. 1
Pt. 2
Pt. 3
Pt. 4
Pt. 5
Pt. 6
Pt. 7
Pt. 8
Pt. 9
Pt. 10
BOD
x
x
x
x
x
x
COD
X
X
X
X
X
X
TSS
x
x
x
x
x
x
O&G
X
X
X
X
NHYN
x
x
x
x
x
x
Total
Nitrogen
x
x
x
x
x
x
x
x
x
Total
Phosphorus
x
x
x
x
x
x
x
x
x
As*
x
x
x
x
x
x
x
x
x
x
Cd
x
x
x
x
x
x
x
x
x
x
Cr
x
x
x
x
x
x
x
x
x
x
Cu
x
x
x
x
x
x
x
x
x
x
Pb
x
x
x
x
x
x
x
x
x
x
Hg*
x
x
x
x
x
x
x
x
x
x
Mo*
x
x
x
x
x
x
x
x
x
x
Ni
x
x
x
x
x
x
x
x
x
x
Se
x
x
x
x
x
x
x
x
x
x
Ag
x
x
x
x
x
x
x
x
x
x
Zn
x
x
x
x
x
x
x
x
x
x
CN
x
x
x
x
% solids
x
x
x
Flow
x
x
x
x

H. Detection level and Sample Method
P. O. C.
Detection Level (m 1)
Sam le Method
BOD
2
24 hr Composite
COD
50
24 hr Composite
TSS
2
24 hr Composite
NH3
0.1
24 hr Composite
As
0.01
24 hr Composite
Cd
0.002
24 hr Composite
Cr
0.005
24 hr Composite
Cu
0.002
24 hr Composite
Pb
0.01
24 hr Composite
Hg
0.0002
24 hr Composite
Mo
0.1
24 hr Composite
Ni
0.01
24 hr Composite
Se
0.01
24 hr Composite
Ag
0.005
24 hr Composite
Zn
0.01
24 hr Composite
CN
0.01
Grab
Sampling, Preservation and analytical methods will conform with 40 CFR 136 requirements.

RE: McDowell Creek WWTP Phase III Improvements Contract 2 -Quest ions C�YwI -
Ncoo 3& Z77
Subject: RE: McDowell Creek WWTP Phase III Improvements Contract 2 - Quest ions
Date: Mon, 16, Oct 2000 07:11:01 -0500
From: "Parker, David M. (Dave)" <[e-mail]>
To: "Becker, Maggie A." <[e-mail]>,
"Susan Wilson @ NC-DWQ" <susan.a.wilson @ncmail.net>
Susan,
The engineer's certification for the expansion to 6 mgd was sent to Dave
Goodrich on April 28, 1999.
The Authorization to Construct could be sent to either Doug Bean (Director)
or Barry Gullet (Deputy Director). I think the last one we received was
officially addressed to Doug Bean. Either way, can you please copy us also?
Thanks for your help on this.
David M. Parker, P.E.
Black & Veatch
8604 Cliff Cameron Drive, Suite 164
Charlotte, North Carolina 28269
* Phone: [phone]
* Fax: [phone]
* E-mail: [e-mail]
> -----Original Message -----
> From: Becker, Maggie A.
> Sent: Friday, October 13, 2000 5:21 PM
> To: Parker, David M. (Dave)
> Subject: FW: McDowell Creek WWTP Phase III Improvements Contract 2 -
> Questions
> Hi, Dave. Susan is asking questions that I don't have answers to - help!
> -----Original Message -----
> From: Susan Wilson[SMTP:[e-mail]]
> Sent: Friday, October 13, 2000 4 : 41 PM
> To: Becker, Maggie A.
> Subject: Re: McDowell Creek WWTP Phase III Improvements Contract 2 -
> Questions
> Maggie,
> Thanks for the info. Also, excuse my ignorance on this, but have you
> ( they)
> submitted their Engineer's Certification for completion of the project up
> to 6
> MGD? I have some correspondence that indicates that they're at 6 MGD, but
> I'm
> not positive we've received the certification.
> Is Mr. Bean the primary contact for an Authorization to Construct permit
> letter? I know he's the contact for their NPDES permit, but didn't know
> if he,
> Barry or someone else was more appropriate for this letter. Thanks. I
> was
> hoping to get this out shortly after your response - but it should be
> definitely out Monday (and I'll sign it today).
> Have a great weekend.
> "Becker, Maggie A." wrote:
1 of 2 10/16/00 9:58 AM

RE: McDowell Creek WWTP Phase III Improvements Contract 2 - Quest ions
• `
s >
> > Hi, Susan. I have listed below the information you requested on Oct. 6,
> > 2000.
> > * The existing influent pumps have the following capacities:
> > IP-2 3,150 gpm
> > IP-3 2,900 gpm
> > IP-4 2,900 gpm
> > IP-5 3,150 gpm
> > (Existing IP-1 is currently 600 gpm and will be replaced with a
> > 3,150 gpm pump)
> > * The loading rate for the dewatering system (including both
> BFP's)
> > under normal operating conditions is 600 lb/meter of belt/hour. The
> system
> > will operate in the range of 300 to 1000 lb/meter of belt/hour.
> > Please let me know if you have any other questions!
> > Maggie A. Becker
> > Black & Veatch
> > 8604 Cliff Cameron Drive, Suite 164
> > Charlotte, North Carolina 28269
> > * Phone: [phone]
> > * Fax: [phone]
> > * E-mail: [e-mail]
2 of 2 10/16/00 9:58 AM

SOC Priority Project: No
To: Permits and Engineering Unit
Water Quality Section
Attention: Charles Weaver
Date: August 24, 2000
NPDES STAFF REPORT AND RECOMMENDATION
County: Mecklenburg
MRO No.: 00-57
Permit No. NCO036277
PART I - GENERAL INFORMATION
Facility and Address: Charlotte Mecklenburg Utilities
McDowell Creek WWTP
5100 Brookshire Boulevard
Charlotte, North Carolina 28216
2. Date of Investigation: 6-20-2000
3. Report Prepared by: Samar Bou-Ghazale, Env. Engineer I
4. Persons Contacted and Telephone Number: Ms. Maggie Becker with Black & Veatch, (704) 548-
8461
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 W WTP is located on the right
side of SR 2074 after crossing McDowell Creek.
R1
9
a
Discharge Point(s), List for all discharge points:
Latitude: 350 22' 52" Longitude: 80° 56' 25"
Attach a USGS map extract and indicate treatment facility site and discharge point on map.
U.S.G.S. Quad No.: F15NW U.S.G.S. Quad Name: Lake Norman South, NC
Site size and expansion area consistent with application? Yes.
Topography (relationship to flood plain included): Slopes range from 2 to 4%, the W WTP is not
in a flood plain.
Location of nearest dwelling: None within 1000 feet.
10. Receiving stream or affected surface waters: McDowell Creek
^ III
AUG 2 8 2000
OENR - W.AH OURLITY
POINT SOURCE H;PNCN

Rage Two
a. Classification: WS-IV CA
b. River Basin and Subbasin No.: Catawba 030833
C. Describe receiving stream features and pertinent downstream uses: Receiving stream is
approximately 20 feet wide x 3-5 feet deep. A CMU water intake is located a few miles
downstream on Mountain Island Lake. The lake is used for primary and secondary
recreation as well as water supply source.
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: 6.0 MGD
C. Actual treatment capacity of the current facility (current design capacity): 6.0 MGD
d. Date(s) and construction activities allowed by previous Authorizations to Construct issued
in the previous two years: N/A
e. Please provide a description of existing or substantially constructed wastewater treatment
facilities: The existing WWT facilities consist of two mechanical bar screens, grit
removal, influent pumping, three (3) primary clarifiers, two parallel BNR systems
consisting of Oxic/Anoxic zones, two (2) final clarifiers, four (4) tertiary filters, 4
anaerobic sludge digesters and ultra -violet disinfection.
f. Please provide a description of proposed wastewater treatment facilities: Two
applications for Authorizations to Construct were submitted for construction at the subject
facility. The first Authorization application (AC036277) was submitted on December 14,
1999 for the following additions:
a) The conversion of an abandoned clarifier to a waste activated sludge storage
tank.
b) Gravity belt thickeners.
c) The enclosure of outdoor blowers.
d) The construction of a filtrate equalization basin and other upgrades to comply with
electrical requirements for wastewater treatment facilities.
The second application (AC036277ACC) was submitted on May 18, 2000 for
the following additions: Two belt filter presses, a polymer feed system, a dewatered
sludge conveyor, a filtrate equalization pumping station, and a biosolids storage basin; and
miscellaneous improvements to the headworks structure, influent pumping station, final
clarifiers, effluent filters and UV disinfection.
g. Possible toxic impacts to surface waters: This facility has a good compliance history with
toxicity testing results.
h. Pretreatment Program (POTWs only): CMU has an approved pretreatment program.

Page Three
There are 3 significant industrial users permitted to discharge process wastewater to the WWTP.
2. Residuals handling and utilization/disposal scheme:
a. Residuals are land applied. DWQ Permit No. WQ0000057.
Residuals Contractor: BioGro, Inc.
Telephone No.: [phone].
b. Residuals stabilization: PSRP
C. Landfill: Waste from the grit chamber and bar screen are taken to Mecklenburg County
landfill.
3. Treatment plant classification: Class IV
4. SIC Code(s): 4952 Wastewater Code(s) 01
Main Treatment Unit Code: 11113
5. Other Special Items: N/A
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant Funds or are any public monies involved
(municipals only)? Public monies
2. Special monitoring or limitations (including toxicity) requests: None at this time.
3. Important SOC, JOC or Compliance Schedule dates (Please indicate): N/A
4. Alternative Analysis Evaluation: N/A
5. Air quality and/or groundwater concerns or hazardous materials utilized at this facility that may
impact water quality, air quality, or groundwater: No AQ or GW concerns nor are hazardous
materials utilized at this facility.
PART IV - EVALUATION AND RECOMMENDATIONS
The permittee, Charlotte -Mecklenburg Utilities, has applied for Permit renewal for the subject
facility. The WWTP appeared in good operational condition at the time of the investigation.
CMU requests the following changes:
1-Modify the whole effluent chronic toxicity provisions to reflect DENR's modifications
described in an August 26, 1999, letter from Matt Mattews, Aquatic Toxicology Unit
Supervisor, to Utilities Director Douglas Bean.

Page Four
2- Allow a discharge of up to 6.0 mgd of effluent into Mcdowell Creek on an annual average
basis with no single monthly average to exceed 7.6 mgd.
3- mass -based limits in lieu of concentration based requirements if request 2 above has not
been granted.
It should be noted that the chronic toxicity testing procedures mentioned above will be
automatically implemented for all permits.
The modeling group should provide comments regarding mass -based versus concentration
based limits.
The existing permitted flow is 6.0 mgd (monthly average). CMU is proposing to exceed
80/90% of the permitted discharge per request 2 above. A review of DMR' S for 6/99 thru 5/00
indicates that the effluent quality for this facility is excellent and, therefore, exceeding the design
capacity during some months should not significantly degrade effluent quality.
It is recommended that request (2) above be granted provided that CMU comply with 80/90%
capacity policy.
Pending review and approval by P& E, it is recommended that the permit be renewed.
C l �Oki) � �
ell.
pct-A pro
t a'0V..awPi'
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41
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✓ � 100
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Water Quality ional Supervisor ate

NOTES TO FILE
10/5/00 '� bn/ `*�o
CMU/ McDowell Creek
NCO036277
Current Limits: PF = 6 MGD, BOD5 = 5, NH3-N = 1 , Fecal coliform = 200#/ 100 ml, TR C1= 17
Proposed Units
Capacity
Design Load
Peak Load
Other
Comments
Mech. Bar
1 in. screens, 3 `
17.6 mgd
Should have
- 3 ft/s based
screen
wide
3 ' depth
min. vel of 2-
on 17.6 MGD
3.25 ft/s
OK - per M&E,
. 448
Influent pump (1
3150 gpm =
5 influent
Great (~3.7 x
of 3)
4.5mgd 112 ft
pumps
design flow)
TDH
15,250 gpm
= 22 MGD
Effluent trough
N/A
covers
Filter no. 5 (for 5
9.5' x 53'
1.7 gpm/ft2
4.9 gpm/ft2
Design and peak
OK,
of 5)
SA = 504 `
flow = 17.6 mgd
using all cells
M&E p. 676-678
Deep bed -
504*5 = 2520
SA=2500 ft2
Range - 2-10
denitrification
gpm
filters
Depth - 72"
Flow rates lower
with deep bed
UV disnfection
24.5'x32x86 in.
Designed for 18
3 new
OK
New channel
6
mgd peak flow
modules/chann
Ref. specs
modules/chann
with a 3
el being added
performance
el; 40
channels
to 1 &2
guarantee
lamps/module
operational
6*3*40 = 720
12 new modules
Spec'd to meet
lamps
added
200/400 fecal
specs p. 13700
coliform

Proposed Units
Capacity
Design Load
Peak Load
Other
Comments
Digester
3 primary
48,000 gpd
68,000 gpd
OK, plenty of
reconflg.
digester
(sludge flow -
(sludge flow -
storage capacity
1 secondary
annual avg)
monthly max)
(see talcs.
Dia = 55'
@3% TS
@3% TS
below)
SAO = 27'
Also, 503s
Vol = 139,000
reviewed with
ft3
any land
= 2@ 1 MG
app/composting
= 2@ 0.5
permits
MG
Belt filter
2m
Sludge/annual
Avg. load =
Typical rates:
OK
presses
20% dry solids -
avg=
600 lb/m*hr
200-1500
M&E p.866
- reserved area
dewatered
7816+4130+752
lb/m*hr
for 3
Influent
7
= 2*600*2
flow=100 gpm
= 19473 Ibs/day
2400 lb/hr
hydraulic:
= 811 lbs/hr
25-100 gpm/m
Max. month=
Reported range
10891 +6150+ 10
= 300 - 1000
438
lb/m*hr
= 27479 lbs/day
= 1145 lbs/hr
Filtrate EQ
Submersible
OK - can be
pump station
@500 gpm each
controlled
3 pumps
64' TDH
Biosolids storage
Est. 30 day
ad w/roof
storage capacity
- all floor drains from belt filter area and biosolids storage diverted back to filtrate EQ
Sludge digestion/storage:
At 6 MGD, assume BOD in = 220 mg/1, BOD out = 5 mg/l, 0.77 lbs sludge/# BOD5
6.0 * 8.34 * 215 * 0.77 = 8284 lbs sludge/day
At 3% solids,
8284/(0.03*8.34) = 33,110 gal/day sludge produced
For 30 day capacity, need at least 33,110 gal/day * 30 days = 993,300 gallons storage
(easily met at least through secondary digesters and even more so after belt presses).

McDowell Creek WWTP Phase III Improvements Contract 2 - Questions
` Subject: McDowell Creek WWTP Phase III Improvements Contract 2 - Questions
Date: Tue, 10 Oct 2000 09:26:47 -0500
From: "Becker, Maggie A." <[e-mail]>
To: Susan Wilson <susan.a.wilson @ncmail.net>
Hi, Susan. I have listed below the information you requested on Oct. 6,
2000.
* The existing influent pumps have the following capacities:
IP-2 3,150 gpm
IP-3 2,900 gpm
IP-4 2,900 gpm
IP-5 3,150 gpm
(Existing IP-1 is currently 600 gpm and will be replaced with a
3,150 gpm pump)
* The loading rate for the dewatering system (including both BFP's)
under normal operating conditions is 600 lb/meter of belt/hour. The system
will operate in the range of 300 to 1000 lb/meter of belt/hour.
Please let me know if you have any other questions!
Maggie A. Becker
Black & Veatch
8604 Cliff Cameron Drive, Suite 164
Charlotte, North Carolina 28269
* Phone: [phone]
* Fax: [phone]
* E-mail: [e-mail]
1 of 1 10/10/00 11:06 AM

February 22, 2000
Note to File
Subject Sites:
Sugar Creek WWTP
Irwin Creek WWTP
McAlpine Creek WWTP
Mallard Creek WWTP
McDowell Creek WWTP
NPDES PERMIT
NCO024937
NPDES PERMIT
NCO024945
NPDES PERMIT
NCO024970
NPDES PERMIT
NCO030210
NPDES PERMIT
NCO036277
RE: Application of 1/2 FAV Calculation to the Subject
Sites
Joe has revised Maximum Daily Load effluent limits for only those parameters where
values increased (i.e. became less stringent) applying the latest 1/2 FAV calculations (see
Sue Wilson's memo dated January 2, 2000). Because this was "a minor mod at the
request of the permittee for revision of cyanide only," parameter values that would have
become more stringent, were not upgraded (per Dave Goodrich).
Therefore upon renewal of these permits, the next permit writer must
upgrade the other Daily Maximum parameters to the latest calculations.
Joe Corporon
NPDES Unit
cc. to each subject permit file

Division of Water Quality
August 5, 1999
MEMORANDUM
TO: Dave Goodrich
THROUGH: Matt Matthews f^fj�
FROM: Kristie Robeson VP —
SUBJECT: NPDES Permit Modifications
Revised Chronic Toxicity Language
Due to recent discussions with EPA Region IV, the Division is further modifying its
Whole Effluent Toxicity Enforcement Policy. Therefore, the -chronic toxicity language to be
used in permits will once again change. Listed below are the nine facilities that currently have
a Phase H chronic toxicity testing requirement in their NPDES permits. Our office previously
sent you a memo dated 5/10/99 requesting modification of these nine permits to include the
new chronic toxicity language. However, through discussions with EPA, our office was told
that they would not approve permits which contained that toxicity language. The chronic
language has since been revised and approved by EPA Region IV. Our office now
recommends modifying the permits for the nine facilities listed below to include the revised
permit language for chronic toxicity testing.
CMUD-McAlpine WWTP
NPDES Permit No. NC0024970
Mecklenburg County
CMUD-Mallard Creek WWTP
NPDES Permit No. NC0030210
Mecklenburg County
CMUD-McDowell Creek WWTP
NPDES Permit No. NC0036277 ;1
Mecklenburg County
Concord Rocky River WWTP
NPDES Permit No. NC0036269
Cabarrus County
Delta Mills
NPDES Permit No. NC0006190
Catawba County
Duke Power -Lincoln Turbine
NPDES Permit No. NC0080781
Lincoln County

Takeda Chemical Products
NPDES Permit No. NC0059234
New Hanover County
Winston-Salem Archie Elledge WWTP
NPDES Permit No. NC0037834
Forsyth County
Winston -Salem -Lower Muddy Creek WWTP
NPDES Permit No. NC0050342
Forsyth County
Please find attached the appropriate chronic toxicity test condition language to be
used in these nine permit modifications. You should also note that this language contains our
new mailing address, which should be used in future toxicity permit language. Should you
have any questions, please feel free to contact me or Matt Matthews at 733-2136.
Attachment
cc: Rex Gleason-MRO
Rick Shiver-WIRO
Larry Coble-WSRO
Colleen Sullins
Shannon Langley -Point Source Compliance/Enforcement Unit

CHRONIC TOXICITY PERMIT LIMIT (QRTRLY)
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality to
Ceriodaphnia dubia at an effluent concentration of %.
The permit holder shall perform at a minimum, quarterly monitoring using test procedures outlined in the "North Carolina
Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised February 1998, or subsequent versions or "North Carolina
Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -February 1998) or subsequent versions. The tests
will be performed during the months of . Effluent sampling for this testing shall be performed at the
NPDES permitted final effluent discharge below all treatment processes.
If the test procedure performed as the first test of any single quarter results in a failure or ChV below the permit limit, then
multiple -concentration testing shall be performed at a minimum, in each of the two following months as described in
"North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -February 1998) or subsequent
versions.
The chronic value for multiple concentration tests will be determined using the geometric mean of the highest
concentration having no detectable impairment of reproduction or survival and the lowest concentration that does have a
detectable impairment of reproduction or survival. The definition of "detectable impairment," collection methods,
exposure regimes, and further statistical methods are specified in the "North Carolina Phase H Chronic Whole Effluent
Toxicity Test Procedure" (Revised -February 1998) or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge Monitoring
Form (MR-1) for the months in which tests were performed, using the parameter code TGP3B for the pass/fail results and
TBP3B for the Chronic Value. Additionally, DWQ Form AT-3 (original) is to be sent to the following address:
Attention: Environmental Sciences Branch
North Carolina Division of
Water Quality
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Branch no later than 30 days after
the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/physical measurements and all
concentration/response data, and be certified by laboratory supervisor and ORC or approved designate signature. Total
residual chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for disinfection of
the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the
permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the facility
name, permit number, pipe number, county, and the month/year of the report with the notation of "No Flow" in the
comment area of the form. The report shall be submitted to the Environmental Sciences Branch at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring will be required
during the following month.
Should any test data from this monitoring requirement or tests performed by the North Carolina Division of Water Quality
indicate potential impacts to the receiving stream, this permit may be re -opened and modified to include alternate
monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control organism survival,
minimum control organism reproduction, and appropriate environmental controls, shall constitute an invalid test and will
require immediate follow-up testing to be completed no later than the last day of the month following the month of the
initial monitoring.
QCL Version 5199

March 31, 2000
•
CHARLOTTE.
Mr. Charles H. Weaver, Jr.
NC DENR / Water Quality / NPDES Unit
1617 Mail Service Center --
Raleigh, NC 27699-1617 Ls I' u' r:
Subject: NPDES Permit Renewal r J
McDowell Creek WWTP
Permit No. NCO036277 I
Mecklenburg County J
Dear Mr. Weaver:
This cover letter and attached NPDES Permit Application constitute our request to renew
the subject NPDES Permit which expires on September 30, 2000. We are sending the
original letter and completed application form and two additional copies of each as
directed. The application form includes an attachment with the required narrative
description of the sludge management plan for the facility (See Attachment 5). We
understand from your February 10, 2000, letter that no renewal fee payment is required
as part of this application and that this package includes all that is required by us to
apply for this renewal.
The McDowell Creek WWTP currently operates under a phased NPDES Permit that
became effective November 1, 1995. That permit provides for the operation of the facility
at 3.0 mgd, expansion to 3.5 mgd, and expansion to 6.0 mgd, all subject to NC DENR's
issuance of appropriate approvals and authorizations of construction. Each phase of the
permitted expansion has been successfully completed and is now in operation. The
most recent was certified complete by our consulting engineer (Black & Veatch) by letter
to DENR's Dave Goodrich dated April 28, 1999, which includes the Engineer's
Certification by David Parker dated April 26, 1999. The facility is currently performing
and operating in compliance with all permit requirements.
Mecklenburg County has implemented an aggressive "Surface Water Improvement
Management" (S.W.I.M.) Program since the last renewal of the McDowell Creek Permit.
The S.W.I.M. Program has a number of components that are to be implemented over
time. One that has already been implemented and adopted by the County Commission,
Town of Huntersville, Town of Cornelius, and Town of Davidson establishes stream
buffers to reduce non -point source pollution. The buffer widths vary according to the
size of the drainage area. While this is not directly a change at the McDowell Creek
WWTP, it is a change that is expected to have a positive impact on the basin. It is also
an example of the voluntary commitment and cooperation of the several agencies who
have jurisdiction or operations that can impact the environment.
Another component of the County's S.W.I.M. Program, Phase I, is the development of a
watershed based management program focusing on both point and non -point sources of
pollution with the overall goal of restoring water quality conditions in Mecklenburg
County's streams. A key part of this process is the involvement of the community in
proactive measures to improve water quality conditions. This initiative is being launched
by Mecklenburg County as a pilot in the McDowell Creek basin beginning in 2000 and is
Administrative Division 5100 Brookshire Blvd. Charlotte, NC 28216 Phone: [phone] Fax: [phone]
Charlotte -Mecklenburg Utilities

being called "Water Improvements Now," or WIN. The plan is to use WIN as a spring
board to develop the techniques necessary to carry this watershed based/community
involvement approach forward into the rest of the County as part of Phase II of S.W.I.M
This effort has already begun in the McDowell basin through conducting over 30
presentations to community groups and launching volunteer efforts such as Adopt -A -
Stream, Storm Drain Stenciling and volunteer monitoring. A kick off meeting for the
community involvement campaign is being planned for April 2000.
A comprehensive water quality model will be developed through the WIN project which
will be used as a planning tool for future development and will also act to identify water
quality problem areas and the appropriate best management strategies to reduce non -
point sources of pollution. Mecklenburg County has allocated $100,000 toward this
effort and is in the process of contracting with a private consulting firm for development
of the model. The development of this model is being coordinated with Utilities as part of
our study of the McDowell basin for future sewer needs. Mecklenburg County's water
quality model will be expanded to included the rest of the County as part of S.W.I.M.
Phase II and the expansion of the watershed based management strategy county -wide
which is planned for 2002.
We request that the renewal of the subject permit include two changes from the current
permit. First, please modify the whole effluent chronic toxicity provisions to reflect
DENR's modifications described in an August 26, 1999, letter from Matt Matthews,
Aquatic Toxicology Unit Supervisor, to Utilities Director Douglas Bean. These
modifications provide for an initial quarterly test (either pass/fail or multiple concentration
(ChV)). In the event of failure of that test, the permittee is required to perform additional
multiple concentration tests in the two months following the failure.
Second, we request that the permit should allow a discharge of up to 6.0 mgd of effluent
into McDowell Creek on an annual average basis with no single monthly average to
exceed 7.6 mgd. This change more accurately reflects the design of the facility
approved by NC DENR and NC DENR's methods for consideration of water quality
impacts and therefore does not constitute an increased discharge. Alternatively, we
would be interested in receiving a mass -based permit in lieu of concentration based
requirements. We believe that either scenario will provide excellent protection of the
receiving waters and allow the plant to perform up to the design criteria used to establish
the limits.
Please let me know immediately if this application package is incomplete or if you need
additional information. We are available to meet with you as needed to clarify the
application package or to provide additional information. We look forward to hearing
from you.
Sincerely,
CHARLOTTE MECKLENBURG UTILITIES
Douglas BQn
Key Business Executive

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
SECTION 111. INDUSTRIAL WASTE CONTRIBUTION TO MUNICIPAL SYSTEM
Submit a separate Section III for each Significant Industrial User.
1. Significant Industrial User (SIU)
An SIU has (or could have) significant impact on the POTW receiving the wastewater or upon the quality of effluent from the receiving POTW.
Specifically, an SIU:
• has a flow of 50,000 gallons or more per average workday;
• has a flow greater than 5 percent of the total flow carried by the municipal system m receiving the waste, or
• has a toxic material in its discharge.
It may be necessary to alter these administrative criteria in certain cases, such as an instance where two or more contributing industries in
combination can produce an undesirable effect on either the municipal facility or the quality of its effluent.
Name of SIU Ingersoll Rand Company
Street address 800-A Beatty Street
City Davidson County Mecklenburg
State NC Zip Code 28036
Telephone Number ( 704 ) 896-4750
Fax Number ( 704 ) 896-4606
e-mail address
2. Primary Product or Raw Material
Specify either the principal product or the principal raw material and the maximum quantity per day produced or consumed.
Quantities are to be reported in the units of measurement for each SIC category at the facility. SIC categories should use the units of
measurement normally used by that industry.
Product
Raw Material
Quantity
Units
Air Compressors
1. Tubing & small machine components
2. Phosphate bath & acid rinse (tube cell
washer)
3. Paint in paint booth
4. Aqueous cleaner in the cabinet washers
500 — 600
unitslmonth
Max production is
700 un'dslmonth
3. Flow
Indicate the volume of water discharged into the POTW and whether this discharge is intermittent or continuous
0.0016 MGD n Intermittent X Continuous
SIU is permitted to discharge 0.007 mgd daily maximum flow, 0.005 mgd average monthly flow
Pretreatment consists of 1-5,000 gallon flow equalizationtank,1-oil/water separator,1-1,000 gallon treatment tank, 1- ultra filtration
unit
4of16
McDowell Creek WWTP NPDES Permit No. NCO036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MOD or with pretreatment programs
Attachment 1
Facility Description
Present Operating Status
McDowell Creek VW TP provides advanced wastewater treatment to serve northern
Mecklenburg County. While a complete description is provided below, in summary the
plant includes influent pumping, screening, grit removal, primary clarification, biological
treatment through activated sludge and biological nutrient removal (BNR) processes,
secondary clarification, effluent filtration, and ultraviolet (UV) disinfection. Solids are
anaerobically digested. The plant has sand drying beds available for solids dewatering,
but is currently using a mobile belt filter press to perform this operation. Solids are land
applied.
The design hydraulic flows for the plant are:
Average day 6.0 mgd
Maximum Month 7.6 mgd
Peak (all pumps) 17.6 mgd
The current process train consists of:
1. Liquid train
❑ Influent Pumping
❑ Mechanical bar screens
❑ Aerated grit removal
❑ Primary Clarifiers
o Trickling filters (Not used during BNR)
❑ Anaerobic basins
❑ Anoxic Basins
❑ Oxic Basins
❑ Final Clarifiers
❑ Deep bed effluent filters w/ de -nitrification capability
❑ Ultraviolet Disinfection
2. Solids Train
❑ Two anaerobic digesters
o Sand drying beds
Headworks
Wastewater enters the plant through a 36 inch gravity sewer line. Upon entering the
headworks area, the flow is screened by a mechanical bar screen with 1-inch openings.
Flow is then measured by an ultrasonic flow meter over the 24-inch parshall flume
before being pumped to the preliminary treatment structure.
❑ Mechanical bar screen -1
❑ Hydraulic capacity, mgd -17.6
Influent Pump Station
The Influent Pump Station has 5 lift pumps with a total pumping capacity of 13,400
gpm (19.3mgd).
5 of 16
McDowell Creek WWTP NPDES Permit No. NCO036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
❑ Pump 1, gpm - 600
❑ Pump 2, gpm - 3500
❑ Pump 3, gpm - 2900
❑ Pump 4, gpm - 2900
❑ Pump 5, gpm - 3500
❑ Pumps no. 2 and no. 5 are immersible with AFD control.
Preliminary Treatment structure
The preliminary Treatment structure consists of the following equipment:
❑ One mechanical bar screen with a hydraulic capacity of 17.6 mgd
❑ Two aerated grit chambers with a volume of 4500 cubic feet and a total hydraulic
capacity of 17.6 mgd
❑ Equipment associated with preliminary treatment including an air lift grit pump,
blowers, dewatering screws and a belt conveyor.
Primary Clarifiers
There are three primary clarifiers with a total volume of 619,200 gallons.
Primary Volume (gallons) Design Hydraulic Design Hydraulic
Clarifier Loading (Avg Day, Loading (Max Day,
No. mgd) mgd)
❑ 2 133,000 1.65 4.85
❑ 3 352,600 2.70 7.9
Solids are removed to the anaerobic digesters by 5 positive displacement diaphragm
pumps.
Tricklinq Filters
Under normal operating conditions the filters are not used because of their detrimental
effect on the BNR process.
o Two filters with rock media - total design capacity of 17.6 mgd.
Anaerobic, Anoxic, and Oxic Basins
McDowell Creek WWTP was originally constructed to provide two -stage activated sludge
treatment with intermediate clarification. During the 1995-1998 expansion, it was converted to
use a single stage process and to provide BNR. The original sequential aeration basins were
re -configured to become parallel trains and the intermediate, circular clarifiers were converted
into aeration basins. The result is that there are currently 4 rectangular basins with anoxic and
anaerobic zones, and 3 circular aerobic basins. In addition, new basins were constructed to
provide anaerobic zones for BNR.
The tables below describe the current configurations and design criteria.
6of16
McDowell Creek WWTP NPDES Permit No. NCO036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
Parameter
Anaerobic detention time, hr
Anoxic detention time, hr
Oxic detention time, hr
Solids retention time, days
MLSS, mg/I
Total RAS flow @ 0.6% TS, mgd
Design criteria @
design Average day flow (6.0 mgd)
1.5 hr
2.1 hr
8.6 hr
11 hr
1,850 mg/I
2.5 mgd
The circular and rectangular aeration basins provide a total detention time of 12 hours at 6.0
mgd average day flow and 9.5 hours at 7.6 mgd max. month flow. Basins 1.1 and 2.1 (the
rectangular basins) are partitioned to provide approximately 20 percent anoxic detention
leaving the remainder for oxic (aerated) detention.
Basin 1.1
Anaerobic Anoxic
Basin 2.1
Anaerobic Anoxic
Number of cells per zone
4
4
4
4
Nominal cell size, ft
21 x 21
28 x 23.5
21 x 21
28 x 22
Sidewater depth, ft
14
14
14
14
Cell volume, cu ft
6,170
99200
6,170
8,620
Hydraulic Loading Per Basin
Annual Avg Flow, mgd
3.0
3.0
3.0
3.0
Max Month Flow*, mgd
6.8
21.5
6.8
21.5
*Includes RAS recycle, oxic recycle, and internal (anoxic) recycle for UCT BNR mode.
Basin 1.1
Basin 2.1
Anaerobic
Anoxic
Anaerobic
Anoxic
Mixing intensity
(bhp/1000 cu ft)
0.75
0.75
0.75
0.75
No. of mixers per cell
1
1
1
1
Motor horsepower,
hp each
7.5
7.5
7.5
7.5
Motor rpm
385
385
385
385
No. of anoxic recycle
pumps
n/a
2
n/a
2
Flow rate range
per pump, gpm
n/a
500-1,320
n/a
500-1,320
Motor horsepower,
hp each
n/a
1.5
n/a
1.5
OXIC RECYCLE
7 of 16
McDowell Creek WWTP NPDES Permit No. NC0036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
Submersible pumps mounted in the circular aeration basins are used to return oxic
MLSS from the circular aeration basins to either the first or second cell of the anoxic
zones of basins 1.1 and 2.1. The pumps are equipped with adjustable frequency drive
control to provide a pumping range of 6.0 -15.2 mgd.
Number of pumps 4
Type Submersible centrifugal
Location Aeration basins 1.2, 1.3, 2.2
Rated capacity, gpm each
ORP-1.1
5,500
ORP-1.2
51500
ORP-2.1
5,500
ORP-2.2
5,500
Capacity range, gpm each
21625-5,500
Pumping capacity, gpm
Installed
11,000
Firm
5,500
Rated head, ft 32
Horsepower, each pump
ORP-1.1
75
ORP-1.2
75
ORP-2.1
75
ORP-2.2
75
Drives Adjustable speed
Control Local HO
Blower No.
SUM
Motor HP
B-1
29100
150
B-2
21100
150
B-3
3,148
200
B-4
3,148
200
Total Capacity (all units in service)
10,496
Firm capacity (largest unit out of service)
71348
Discharge Pressure, psi
7.5
Control
Automatic
Final Clarifiers
2 - Flocculating type final clarifiers with the following characteristics:
Hydraulic Loading:
Flow per basin (mgd)
Surface Loading Rate (gpd/sq ft)
Detention Time
Flocculation Well (min)
Total (hrs)
8 of 16
Design Peak
3 8.8
380 1,120
35 12
7.1 2.4
McDowell Creek WWTP NPDES Permit No. NCO036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
Effluent Filters
Effluent filtration consists of deep bed, sand filters with denitrification capability. Acetic
acid is provided as a carbon source to promote biological denitrification within the filters
as needed. Filter effluent flows into a clearwell and then to the ultraviolet disinfection
system. Submersible pumps located in the clearwell provide backwash water to the
filters. The submersible pumps are also used periodically to "bump" the filters with
backwash water to release nitrogen gas bubbles formed by denitrification. Dirty
backwash water flows into a mudwell, which drains by gravity to the plant influent pump
station. Blowers located adjacent to the effluent filters are used for air scour of the
filters.
Physical Dimensions
Number of cells
Cell size (width x length),
each (ft)
Sidewall depth, ft
Depth of mono -media, ft
Effective size of media, mm
Surface area per, cell, ft'
Loading Criteria
Flow (mgd)
Filtration rate
Each cell, gpm/ft2
All cells, gpm/ft2
Ultraviolet Disinfection
n
91- 6" x 531- 0"
20'- 8"
6
2.3
500
Average Day Peak
6.0 17.6
1.7 4.9
2.1 6.1
Disinfection is provided by parallel banks of vertical ultraviolet light modules. Two
channels housing six UV modules are located at the effluent end of the filter structure.
One future channel will be used for six future UV modules.
The system is designed to disinfect a flow of 6.0 mgd to a coliform level of less than
200 organisms/100 ml. The UV lamp cleaning system includes a jib crane for removing
the modules from the channels and a cleaning tank with an air mixing system.
Number of channels
2 + 1 future
Channel width, inches
24.5
Channel length, ft
321- 0"
Channel depth, inches
86
Number of modules
6
Lamps/module
40
Reaeration
A cascade type reaeration structure is provided to increase the effluent dissolved
oxygen to at least 6 mg/L. The reaeration structure consists of flow over horizontal
9of16
McDowell Creek WWTP NPDES Permit No. NCO036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
fixed weirs onto a vertical succession of aluminum steps
10 of 16
McDowell Creek WWTP NPDES Permit No. NCO036277

' NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
Attachment 2
Potential Facility Changes
Charlotte Mecklenburg Utilities has several projects currently underway at the McDowell
Creek WWTP. Here is a synopsis of the current work and other projects anticipated
over the next five years.
Sludge Thickening & Improvements
This project scope includes:
o Improvements to digester complex electrical system to meet NFPA 820 and NEC
requirements
❑ Gravity belt thickeners for waste activated sludge (WAS) thickening
o Waste sludge holding basin with aeration
❑ Enclosing effluent filter backwash blowers for noise control
This project has been submitted to NC DENR for review and an authorization to
construct has been issued. Construction bids are expected by May 2000.
Potable Water Service
The McDowell Creek WWTP currently obtains potable water from an on -site well. It is
planned to extend approximately 10,000 feet of water main to provide public water
supply for potable and fire protection services.
Solids Dewatering & Miscellaneous Improvements
Currently in design, this project scope includes:
o Construction of dewatering building
o Installation of 2 belt filter press units for dewatering anaerobically digested biosolids
❑ Construction of covered storage area for dewatered biosolids
❑ Improvements to the anaerobic digesters and sludge heaters, including the addition
of a third primary digester and a covered sludge/gas storage basin.
❑ New bar screen facilities
❑ Replacement of influent pump No. 1 with larger capacity pump to increase firm
pumping capacity to 17.6 mgd
❑ Up -fitting effluent filter cell no. 5 (shell constructed during last expansion)
❑ Addition of UV disinfection modules to increase disinfection capacity
This project is projected to begin construction during calendar year 2000.
Stand-by Power Improvements
This project will replace the existing plant generator system with a new system rated for
heavier service. The new system will be capable of powering the entire plant in the
event of a power outage and for power peak shaving. The project is currently being
designed and should be in service in late 2000 or early 2001.
11 of 16
McDowell Creek WWTP NPDES Permit No. NC0036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
Effluent Reuse Project
Charlotte Mecklenburg Utilities is negotiating a contract with an area golf course that
will provide treated effluent to them for irrigation. This would replace the well system
that they currently use. Efforts are underway to identify and add other customers.
The project will provide for supplemental disinfection, pumping facilities, controls, and
pipeline from the McDowell Creek WWTP to the customer. The facilities are being
designed at this time. Utilities anticipates a subsequent permit modification request to
include designation of the McDowell Creek plant as a Water Reclamation Facility and to
provide for the additional discharge point(s).
McDowell Creek Basin Study
The McDowell Creek basin is one of the fastest growing areas of Mecklenburg County.
Utilities has initiated a planning study to project the future wastewater treatment needs
for the basin. The study departs from traditional planning studies by including strong
participation by the Town of Huntersville and the Town of Cornelius who control most of
the land use planning for the basin and by addressing the watershed protection issues
presented by potential plant expansion. Both towns are involved in progressive and
innovative land use planning activities. Their involvement will help synchronize the
development and growth plans for the area with the wastewater treatment needs. With
this information as input, the study will evaluate short term and long term watershed
management and wastewater treatment and disposal/reuse alternatives including non -
discharge options. A stakeholders group has been established to provide input to
Utilities in the evaluation of alternatives identified. The stakeholders group includes
representatives from the development community, environmental interests,
neighborhood associations in the basin and on Mountain Island Lake, neighbors of the
plant, owners of significant property in the basin, Mecklenburg County, and the NC
DENR Regional Office.
The Study will produce a plan for comprehensive wastewater management within the
watershed that is in agreement with current land use plans, meets community needs,
and that is focused on protecting the environment. The study is to be completed in the
fall of 2000 and Utilities expects to act quickly on the recommendations.
Rocky River Regional Outfall Project
Several years ago, Charlotte Mecklenburg Utilities entered into a regional agreement
with the Water and Sewer Authority of Cabarrus County (WSACC) to provide sewer
service to the Northeast part of Mecklenburg County and to the Northwest part of
Cabarrus County. The pipelines required to consummate the agreement are currently
under construction. One of the results of the agreement is that all of the wastewater
flow from the Town of Davidson will be re -directed away from the McDowell Creek
WWTP into the Rocky River Regional Wastewater Treatment Plant in Cabarrus County.
It is estimated that this will be reduce flows into the McDowell Creek WWTP by about
750,000 gallons/day starting in 2001. Although there is not a direct impact on the
McDowell Creek WWTP, it is worth noting that this project will also eliminate an
existing, private WWTP discharge into the Rocky River.
12 of 16
McDowell Creek WWTP NPDES Permit No. NCO036277

PRELIMINARY TREATMENT
AVE: 6.0, PEAK: 17.6
MECHANICAL AERATED
BAR SCREEN GRIT CHAMBER
ALUM
PRIMARY PRIMARY PRIMARY
CLARIFIER NO. 1 CLARIFIER NO. 2 CLARIFIER NO. 3
AVE: 1.7 AVE: 1.7 AVEt 2.7
PEAKt 4.9 PEAK: 4.9 PEAK: 7.9
NOTEs ALL FLOWS ARE IN MILLION
GALLONS PER DAY
ANAEROBIC
ANOXIC/OXIC
AERATION
AERATED
BASIN 1.1
BASIN 1.1
BASIN 1.3
GRIT CHAMBER
LIME
AVE: 3.0
AVE: 3.0
AVE: 1.5
PEAK: 9.8
PEAKs 8.8
PEAKs 4.4
BYPASS
AN
AX
OX
ED
TRICKLING
F I LTER
RECYCLE
OX
ACETIC
AERATION
ACID
BASIN 1.2AVE:
GRIT TO PRIMARY SLUDGE
1.5
5
OUMPSTER TO ANAEROBIC
PEAKS 4
DIGESTERS
RECYCLE
INFLUENT
PUMPING
TRICKLING
ANAEROBIC
ANOXIC/OXIC
AERATION
STATION HEADYIORKS
FILTER
BASIN 2.1
BASIN 2.1
BASIN 2.2
AVE: 3.0
AVE: 3.0
AVE: 3.0
PEAK: 8.9
PEAK: 8.8
PEAK: 8.8
MECHANICAL
BAR SCREEN
AN
AX
OX
l_____j
OX
-
---*- \`\\\
AVE: 6.0do
PEAK: 17.6
RFCyr_i a
CASCADE
EFFLUENT FILTER
REAERATION
STRUCTURE
PLANT
AVE: 6.0
AVE: 1.5/FILTER
INFLUENT
PEAK: 17.6
6.0 TOTAL
AVE: 6.0
PEAKS 4.4/FILTER
PEAK: 17.6
17.6 TOTAL
umu
ACETIC ACID/
1R G
METHANOL
UV
DISINFECTION
T
AVE: 6.0
PLANT
PEAK: 17.6
EFFLUENT
AVE : 6.0
PEAK: 17.6
MCDOWELL CREEK
FINAL CLARIFIER NO. 1
AVE: 3.0
PEAKt 8.8
FINAL CLARIFIER NO. 2
AVE: 3.0
PEAKt 8.8
ALUM
Ot/6225 MCKER

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
Attachment 5 — Description of Sludge Management Plan
The sludge management plan for the McDowell Creek VW1 TP is documented in the
"Engineering Design Report, Civil/Mechanical Design Memorandum, McDowell Creek
Wastewater Treatment Plant Facilities Improvements," prepared by Black & Veatch for
the 1995 expansion of the plant. In addition, Charlotte Mecklenburg Utilities has a long-
term contract in place with a private firm that guarantees beneficial re -use / disposal of
all biosolids produced at McDowell and our other facilities.
Sludge stabilization is currently provided through a system of four anaerobic digesters.
Two of the digesters are covered and operate as primary digesters. The third and
fourth are open and are used for sludge storage. The primary digesters are heated and
mixed. The heaters can be fueled by either recovered methane gas from the digesters
or by fuel oil.
Once digested, the biosolids can be discharged to sand drying beds for dewatering.
During the last expansion of the McDowell Creek WWTP, upgrades to the digesters
disrupted normal sludge stabilization processes and resulted in the production of a
higher volume of thinner than normal sludge. The sludge drying beds did not have
enough capacity to handle this increased volume. Utilities contracted for temporary
dewatering with a service provider who used a mobile, belt filter press. Even though
the digesters are now performing well, utilities has continued this practice and plans to
do so until the permanent mechanical dewatering facilities are complete.
Dewatered cake from the belt press may be loaded directly into trucks for removal to
land application sites or to storage at other facilities (see below) or can be stored on -
site in dedicated sand drying beds. Biosolids cake dried and removed from the sand
filter beds is currently stored in three of the sand drying beds that have been dedicated
to this purpose. Covered storage has also been designed and is planned to be
constructed at the McDowell Creek WWTP in conjunction with the dewatering facility.
To address the long term reuse/disposal requirements for the residuals produced at all
of our wastewater and water treatment plants, Utilities conducted an industry -wide,
experience and qualifications based procurement process to select a firm that could
provide the needed services. A ten-year contract was established effective July 1,
1999, that provides for guaranteed beneficial reuse / disposal for all of the residuals
produced during the term of the agreement. The selected firm will use a combination of
land application, lime stabilization, and composting for beneficial reuse. In the event
that these options should become unfeasible and/or unavailable, the firm has
committed to landfill disposal and has guaranteed that the designated landfill will take
the material. The contract establishes a pricing structure for the entire term for all
options. The contractor makes the decision as to how much material is processed
through each option. The contract is secured by a corporate guarantor as well as a
performance bond.
Utilities has provided substantial covered sludge storage facilities at the Mallard Creek
and the Irwin Creek VWVTP's and a lesser amount (in terms of days of production) of
storage at the McAlpine Creek WWTP. The contractor is required to manage and
maintain these facilities. The management requirements include a guarantee that there
is always a minimum amount of space (typically 25% of the total floor space) open for
Utilities' staff to deposit dewatered biosolids cake. Utilities is responsible for putting the
biosolids into the storage facility. The contractor is responsible for managing the
15 of 16
McDowell Creek WWTP NPDES Permit No. NCO036277

NC DENR / DWQ / NPDES PERMIT APPLICATION - STANDARD FORM A
Municipal Facilities with permitted flows > 1 MGD or with pretreatment programs
material in storage and for removal of the material to its final disposition. The contractor
has the option to store material from any of the plants within the storage space
provided. A provision of the contract states that Utilities will provide covered storage at
McDowell Creek with a minimum floor area equivalent to the dedicated sand drying
beds currently being used for that purpose. Again, the contract requires them to
manage the proposed storage facility and to always maintain open space for new
material.
The contractor is also required to identify and obtain permits for all required land
application sites and/or other reuse/disposal alternatives.
The current mode of operation of the contractor is that storage sites are well managed
according to the contract requirements and that all suitable material is land applied for
agricultural benefit. The contractor has modified our Residuals Management Facility
(RMF) (operation and maintenance of which is within the scope of their contract) at
McAlpine Creek UW TP and will soon begin lime stabilization and composting
operations there. It is anticipated that most, if not all, of the biosolids processed
through that facility will be from McAlpine's production. However, the contractor will
decide how much and which material is used at the RMF. It is therefore possible that
some material from McDowell could be used for composting or lime stabilization.
16 of 16
McDowell Creek WWTP NPDES Permit No. NC0036277