NC0024945_Permit Modification_20131003

NPDES DOCIMENT :CANNING COVER SHEET
NPDES Permit:
NC0024945
Irwin Creek WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification""
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
Draft Permit
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
October 3, 2013
This document is printed on reuse paper - ignore any
content on the resrerse side

AA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Resources
Water Quality Programs
Pat McCrory Thomas A. Reeder John E. Skvarla, III
Governor Director Secretary
October 3, 2013
Ms. Jacqueline A. Jarrell, P.E., Superintendent
Environmental Management Division
Charlotte Mecklenburg Utilities
4222 Westmont Drive
Charlotte, North Carolina 28217
Subject: Permit Monitoring Revision for NC0024945
Irwin Creek WWTP
Mecklenburg County
Dear Ms Jarrell:
Division personnel have reviewed and approved your application for a minor modification of the subject
permit. We are forwarding you the new Section A. (1.) Effluent Limitations and Monitoring Requirements page
with footnotes. You should replace your existing Effluent Limitations and Monitoring Requirements sheet with
this revised page, effective October 1, 2013. This permit revision 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 October 15, 2007 (or as subsequently amended).
DWQ guidance regarding the reduction of monitoring frequencies in permits for exceptionally
performing facilities is for NPDES wastewater permits only and do not apply to reclaimed water permits.
The change made in the NPDES permit modification includes:
• A monitoring frequency reduction for CBODS, TSS, NH3-N, and fecal coliform from daily to 2/week.
Please note that the receiving stream, Irwin Creek, is listed as an impaired waterbody on the North Carolina
303(d) Impaired Waters List for copper, lead, and zinc. Also, there is an EPA approved Fecal Coliform Total
Maximum Daily Load (TMDL) for the Irwin, McAlpine, Little Sugar, and Sugar Creek Watersheds. Addressing
impaired waters is a high priority with the Division, and instream data will continue to be evaluated. If there is
noncompliance with permitted effluent limits and stream impairment can be attributed to your facility, then
mitigative measures may be required.
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
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone]
Internet: www.ncwaterauality.orq
An Equal Opportunity \ Affirmative Action Employer
NonrthCarolina
77aturallri

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 a demand is made, this permit shall be fmal and binding.
Please take notice that this permit is not transferable. The Division may require modification 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 Resources or permits required by the Division of Land Resources, Coastal
Area Management Act, or any other Federal or Local governmental permits may be required.
If you have questions concerning this permit, please contact Julie Grzyb by e-mail
([e-mail]) or phone at [phone].
Si cerely,
homas A. Reeder
etr/
Enclosure: NPDES Permit NC0024945 (Modified pages)
cc: Central Files
NPDES Unit
EPA Region 4
Mooresville Regional Office/Surface Water Protection Section
e-copy:
Erin Hall, Mecklenburg County

Permit NC0024945
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS -FINAL
During the period beginning on the effective date of the permit and lasting until expiration, the
Permittee is authorized to discharge treated municipal and industrial wastewater from outfall
001. Such discharges shall be limited and monitored by the Permittee as specified below:
Effluent Characteristics
Limits
Monitoring Requirements
Monthly
Average
Weekly
Average
Daily
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Locationl
Flow
15.0 MGD
Continuous
.Recording
I or E
CBOD, 5-day, 20°C (Summer)2,3
5.0 mg/L
7.5 mg/L
2/Week
Composite
I, E
CBOD, 5-day, 20°C (Winter)2.3
10.0 mg/L
15.0 mg/L
2/Week
Composite
I, E
Total Suspended Solids2
30.0 mg/L
45.0 m9/L
2/Week
Composite
I, E
NH3-N (Surnmer)3
1.2 mg/L
3.6 mg/L
2/Week
Composite
E
NH3-N (Winter)3
2.3 mg/L
6.9 mg/L
2/Week
Composite
E
Dissolved Oxygen4
Daily
Grab
E
Fecal Coliform
200/ 100mI
400/ 100 ml
1000/ 100 ml
2/Week
Grab
E
pH
Not less than
6.0 S.U. or greater
than 9.0 S.U.
Daily
Grab
E
Temperature
Daily
Grab
E
Conductivity
Daily
Grab
E
Total Nitrogen
(NO2-N + NO3-N + TKN)
Monthly
Composite
E
Total Phosphorus5
See Special Condition A. (7.) and A. (8.)
Monthly
Composite
E
Copper, Totals.l
21 µg/L
31 µg/L
Monthly
Composite
E
Chromium, Total
Quarterly
Composite
E
Chronic Toxicity6
Quarterly
Composite
E
Effluent Pollutant Scan9
Monitor and Report
Footnote 9
Footnote 9
E
Footnotes:
1. Sample Location: I- Influent, E - Effluent.
2. The monthly average effluent CBOD5 and Total Suspended Solids concentrations shall not exceed 15% of
the respective influent value (85 % removal).
3. Summer is defined as the period from April 1 through October 31, while winter is defined as November 1
through March 31.
4. The daily average dissolved oxygen effluent concentration shall not be less than 6.0 mg/1.
5. See Special Conditions A. (7.) and A. (8.) for total phosphorus limit and reporting requirements.
6. If CMUD decides to develop site -specific standards, the proposed course of action should be consistent with
"Interim Guidance on Determination and Use of Water -Effect Ratios for Metals" EPA-823-B-94-001,
February 1994. The Division and EPA will review the proposed course of action and may provide comments.
7. The limits stipulated are based on "total recoverable". Alternatively, the permittee may request limits based
on total dissolved as allowed under South Carolina standards.
8. Chronic Toxicity (Ceriodaphnia) at 83%: January, April, July, October (see Special Condition. A. (6.)).
9. The permittee shall perform three Effluent Pollutant Scans during the term of this permit. (See A. (9).)
Definitions:
MGD - Million gallons per day
µg/ L - Micrograms per liter
mg/L - Milligram per liter ml - Milliliter
CBOD - Carbonaceous Biochemical Oxygen Demand
Modified Page Issued 10/3/2013

2012 North Carolina 303(d) List -Category 5
Catawba River Basin
> AU Number
Name
10-digit Watershed 0305010301
Description
Length or Area
Sugar Creek
Units Classification
Category
Category Rating Use
Reason for Rating
Parameter
Year
> 11-137-1 Irwin Creek
From source to Sugar Creek
11.8
FW Miles C
5 Impaired Aquatic Life
5 Impaired Aquatic Life
5 Impaired Aquatic Life
Standard Violation Copper
Standard Violation Lead
Standard Violation Zinc
2010
2008
2010
5
> 11-137-7
McCullough Branch
From source to Sugar Creek
3.1 FW Miles C
5 Impaired Aquatic Life
Poor Bioclassification Ecological/biological Integrity Benthos
1998
5
> 11-137a
Sugar Creek
From source to below WWTP, SR 1156, Mecklenburg
0.3 FW Miles C
5 Impaired Aquatic Life
Poor Bioclassification Ecological/biological Integrity Benthos
1998
5
> 11-137b
Sugar Creek
From SR 1156 Mecklenburg to Hwy 51
10.9
FW Miles C
5 Impaired Aquatic Life
Fair Bioclassification Ecological/biological Integrity Benthos
2000
5
> 11-137c
Sugar Creek
From Hwy 51 NC/SC border
2.5 FW Miles C
5 Impaired Aquatic Life
Standard Violation Copper
2010
5
Catawba River Basin
10-digit Watershed 0305010302
12-digit Subwatershed
030501030202
Twelvemile Creek
East Fork Twelvemile Creel
• 11-138
Twelvemile Creek
From source to North Carolina -South Carolina State Line
3.0 FW Miles C
5 Impaired Aquatic Life Standard Violation Copper 2008
5 Impaired Aquatic Life Standard Violation Turbidity 2008
5 Impaired Aquatic Life Standard Violation Low Dissolved Oxygen 2012
5
12-digit Subwatershed
030501030203
Sixmile Creek
Friday, August 24, 2012
Approved by EPA August 10, 2012
Page 36 of 170

CHARLOTTE.
August 15th, 2013
NPDES Permitting Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
CITY OF CHARLOTTE
CHARLOTTE-MECKLENBURG UTILITIES
Environmental Management
Re: Request for Reduced Monitoring Frequencies for Exceptionally Performing Facilities —
Irwin Creek WWTP — NPDES Permit #NC0024945
Dear NPDES Unit:
Please consider this letter as Charlotte -Mecklenburg Utility Departments request for a minor modification to
Irwin Creek's NPDES permit. We are requesting a reduction of monitoring frequencies for CBOD, TSS,
NH3, and fecal colifomi since Irwin Creek WWTP exceeds the criteria for an exceptionally performing facility
as outlined in the Division of Water Quality's guidance.
Enclosed is the three year data summary of Irwin Creek WWTP's effluent data and DWQ's criteria. Please
note that even if our request is approved, the Utility Department will likely continue to monitor at a frequency
greater than what would be required based on our exceptional history of compliance with these parameters.
If you would like the raw data set please let us know and we will make it available to you at your request.
Please also let us know if you have any questions or if you need any further information. If you do, please
call Shannon Sypolt, Water Quality Program Administrator, at 704/336-4581 or Mike Lingerfelt, ORC of Irwin
Creek WWTP, at 704/357-1344. You may also contact me at 704/336-4460. Thank you for your assistance
with this minor modification.
Respectfully,
?acqueiine A. Jarrell, P.E.
`Superintendent, Environmental Management Division
Charlotte -Mecklenburg Utilities
Cc: M. Lingerfelt, S. Sypolt
www.charlottenc.gov 14222 Westmont Drive I Charlotte, NC 28217 I PH: 704.336.4407

Data Summary for Reduced NPDES Permit Monitoring Frequency
Data Results and Approval Criteria for Irwin Creek WWTP
Data Set - July 1, 2010 - June 30, 2013
Parameters Monthly Weekly # of 3- Year 50% of # of Results > 200 % # of Results > 200 % Max
Limits Limits Samples Results Monthly monthly average weekly average (fecal Daily
Average Limit (CBOD, TSS, NH3) coliform) Result
CBOD
Summer
5
7.5
49
0.3
2.5
0
N/A
6
Winter
10
15
55 1
0.56
5
0
N/A
13
NH3
Summer
1.2
3.6
82
0,05
0.6
0
N/A
1.7
Winter
2.3
6.9
91
0.22
1.15
2 of 15
N/A
7.4
TSS
30.0
45
55
Fecal Coliform
200
400
601
Approval Criteria Met:
0.3
15
0
N/A
11.4
100
N/A
0
7.9
670
1) This facility has not received a civil penalty for a permit violation of the target parameters in the last three years
2) Neither the permitee nor any of its employees have been convicted of criminal violation of the CWA with the previous five years
3) This facility is not under an SOC for target parameter effluent limit noncompliance
4) This facility is not on EPA's Quarterly Noncompliance Report for target parameter limit violations
5) Irwin's three year arithmetic mean is less than fifty percent of the monthly average permit limit for CBOD, TSS, and NH3-N
6) Irwin's three year geomean is less than fifty percent of the monthly average permit limit for fecal coliform
7) Less than 15 daily sampling results over the three year review period are in excess of 200% of the monthly average for CBOD, TSS, and NH3
8) Less than 20 daily sampling results over the three year review period are in excess of the 200% of the weekly average for fecal coliform
9) Irwin has not received any non -monthly average limit violations in the past year for the four target parameters

EFFLUENT ANALYSIS
(NC0024945)
Ammonia
1) 7/12*1.2 mg/L + 5/12*2.3 mg/L = 1.66 mg/L weighted, annual monthly average
0.83 = 50% of wt. annual monthly average
0.204585 three-year average is < 50% of the weighted annual monthly average limit
2) 200% of summer monthly avg. limit = 2.4 mg/L
2010 THRU 2013 7 Samples > 2.4 mg/L
200% of winter monthly permit limit = 4.6 mg/L
2010 THRU 2013 3 Samples > 4.6 mg/L
no more than 15 daily samples exceeded 200% of the monthly average
3) no more than two weekly average limit violations in 2012 (zero shown)
Reduce Monitoring Frequency for NH3-N to 2/week
Fecal
1) 3.781959 geo averac 2010-7/2013
< 100/100mL or 50 % of permit limit
2) 200% of 400/100 mL = 800/100mL
1 daily samples > 200% of permit limit
< 20 daily samples exceeded 200% of the 400/100 mL permit limit
3) no more than two weekly average limit violations in 2012 (zero on record)
Reduce monitoring Frequency for fecal coliform to 2/week
CBOD
7/12*5 mg/L + 5/12*10 mg/L = 7.1 mg/L weighted monthly average
3.54 = 50% of wt. annual monthly average
avg. = 2.1: three-year average is < 50% of the weighted annual monthly average limit
200% of summer monthly avg. limit = 10 mg/ no summer values >10
2010 0 2011 0 2012 0 2013 0
200% of winter monthly permit limit = 20 no winter values > 20
2010 0 2011 0 2013 0
0 0 0
no daily samples exceeded 200% of monthly average winter limit
no more than two weekly average limit violations in 2012 (zero on record)
Reduce Monitoring Frequency for CBOD5 to 2/week
Suspended Solids
1) 30 mg/L monthly average permit limit
15 = 50% of monthly average permit limit
avg. = 2.6 three-year average is < 50% of the monthly average permit limit
2) 200% of monthly average permit limit= 60 mg/L
2010 thru 7/2013 reviewed
no daily samples exceeded 200% of the monthly average limit
3) no more than two weekly average limit violations in 2012 (zero on record)
Reduce Monitoring Frequency for TSS to 2/week

Grzyb, Julie 1`/\` eer O"L rc
Subject: NC0024945 monitoring frequency reduction
Dave Cole,
I have reviewed your concerns regarding the Irwin Creek WWTP. Please note that the request is for conventional
pollutants (Total Suspended solids, ammonia -nitrogen, fecal coliform, and carbonaceous biochemical oxygen demand
and not for any reduction in metals or mercury testing. Also, note that the monitoring reduction is allowed because the
Irwin Creek WWTP has demonstrated consistent, long-term treatment performance at levels far below effluent
limitations for many years. The modification reduces sampling for the four parameters listed above from daily to twice
per week. If the facility samples more frequently they are required to report all the results.
Problems with the sludge, its disposal and testing, are regulated under the Non -discharge permit ND0080900 and should
be directed to the NC Division of Water Resources, Aquifer Protection Unit. This monitoring reduction is for the facility's
treated wastewater being discharged to Irwin Creek under its NPDES permit NC0024945. All testing performed on the
wastewater being discharged from Irwin Creek WWTP is performed by a NC certified laboratory.
Unfortunately, pipes in sewer systems can break or be broken and some overflows will occur. The Division has field
personnel in the Mooresville Regional Office that will assess CMUD's response and make sure repairs were performed as
quickly as possible or fines will be assessed.
Attached please find the modified effluent sheet being issued to Charlotte Mecklenburg Utilities which reduces sampling
for the conventional parameters listed above under its NPDES permit NC0024945. If you have additional questions
regarding this permit, you are welcome to contact me at the address, email, or phone number as listed below.
Respectfully,
Julie Grzyb
Julie A. Grzyb, Environmental Engineer
NC DENR / Division of Water Resources / Surface Water Protection Section
NPDES Complex Permitting, Point Source Branch
1617 Mail Service Center, Raleigh, NC 27699-1617
919/807-6389 (wk); 919/807-6489 (fax)
[e-mail]
E-mail correspondence to and from this address may be subject to the North Carolina Public Records law and may be
disclosed to third parties.
From: Dave Col[mailto:[e-mail]]
Sent: Thursday, ptember 12, 2013 12:21 PM
To: Grzyb, Julie; [e-mail]
Subject: Re: NC0024945
Hi Julie -
N
Thank you for getting back to me so quickly - permittee's request is troubling.
i