NC0024945_Correspondence_20030808

NPDES DOCUMENT SCANNING 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:
August 8, 2003
Thies document is printed on reuse paper - ignore any
content on the re' rerece aside

Michael F. Easley, Govemor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan Klimek, Director
Division of Water Quality
August 8, 2003
Mr. Barry Gullett, P.E., Deputy Director
Charlotte -Mecklenburg Utilities
5100 Brookshire Boulevard
Charlotte, NC 28216
Subject: Water Quality Modeling needs in Response to the Request for Speculative Limits for McAlpine
Creek WWTP, Sugar Creek WWTP, and Irwin Creek WWTP.
Dear Mr. Gullett,
It was a pleasure meeting with you on July 30, 2003 to discuss the proposal for expansion of flow limits at
the Charlotte Mecklenburg Utilities Department WWTPs. Your steps toward addressing the
environmental implications of additional flows at these facilities are appreciated and it is our desire to
work closely with you to address any related issues.
The following issues will be discussed as they relate to the Impaired Waters List of the North Carolina
Water Quality Assessment (2002 Integrated 305(b) and 303(d) Report and the proposed increase in
permitted flows:
1. Metals
2. Dissolved Oxygen and BOD
3. Nutrients
4. Total Suspended Solids
5. Pathogens as measured by the presence of Fecal Coliform
Metals
Currently, South Carolina's 2002 303(d) list (http://www.scdhec.net/egc/water/pubs/303d2002.pdf),
includes Sugar Creek impaired for Copper as an "listing in error" on the 2000 303(d) report that was not
carried over to the 2002 303(d) report. Following our conversation on July 30, 2003, we confirmed with
SC DHEC that Sugar Creek is not listed as impaired by elevated Cu. Furthermore, each of the receiving
waters under concern, Irwin Creek, McAlpine Creek, and Sugar Creek currently meet all water quality
standards for metals. Given this, no additional exercise in water quality modeling is require if CMUD
anticipates that effluent concentrations will remain at or below the current permitted levels following any
increase in permitted flow.
VA
NCDEt'
N. C. Division of Water Quality 1617 Mail Service Center Raleigh, NC 2f7699-1617 [phone] Customer Service
1 800 623-7748

Dissolved Oxygen and BOD
Based on North Carolina's 2002 Integrated 305(b) and 303(d) report, the three receiving waterbodies
under consideration currently meet Surface Water Quality Standards for dissolved oxygen. South Carolina
has identified downstream waterbodies, specifically Cedar Creek Reservoir, as impaired due to low
dissolved oxygen, however, this reservoir is considerably far downstream from the CMUD facilities.
As discussed in our July 30th meeting, the request for additional permitted flow may have consequence on
effluent biochemical oxygen demand and on downstream dissolved oxygen levels. Given this potential,
the DWQ Modeling/TMDL Unit requests that CMUD conduct long-term BOD in addition to BOD5
testing to support the development of a receiving water quality model aimed at addressing any of the flow
scenarios under consideration (originally, three at the July 30th meeting). DWQ recommends the use of
QUAL2E, however, if CMUD has identified a different model(s) that is determined to be more
appropriate, DWQ requests that staff training (if necessary) be provided by CMUD such that proper
review can be conducted.
Nutrients
As per the settlement agreement signed by CMUD, South Carolina Department of Health and
Environmental Control and the North Carolina Division of Water Quality on July 15, 2002, phosphorus
limits have been identified for McAlpine Creek WWTP, Sugar Creek WWTP, and Irwin Creek WWTP.
As per our meeting on July 30, 2003, it is DWQs understanding that no additional annual phosphorus load
will result following an increase in the requested flow and that this would be accomplished through
implementation of additional phosphorus control measures. Given this understanding and those outlined
in the settlement agreement on July 15, 2002, no additional water quality modeling is required by the
Division of Water Quality to address phosphorus.
Currently, there are no total nitrogen or. ammonia (NH3 as N) impairment listings on McAlpine, Sugar, or
Irwin Creeks. If CMUD anticipates that additional flows would result in meeting the current permitted
ammonia effluent concentrations then additional water quality modeling analyses is not required.
Total Suspended Solids
Each of the three receiving waters, McAlpine Creek, Sugar Creek, and Irwin Creek have been placed on
the Impaired Waters List of the North Carolina Water Quality Assessment and Impaired Waters List
(2002 Integrated 305(b) and 303(d)) Report at multiple locations based on excessive turbidity. At this
time, it is anticipated that the additional requested flow under consideration would not directly result in
increasing turbidity in the receiving water bodies. Hence, additional modeling is not required at this time.
However, CMUD discharges, along with other point and nonpoint sources may be addressed and receive
wasteload or load allocations when TMDLs are developed for turbidity in these or downstream
waterbodies.
Pathogens as measured by the presence of Fecal Coliform
North Carolina DENR's 2000 303(d) list of impaired waterbodies identified stream segments in the
Sugar, Little Sugar, and McAlpine Creek watersheds, as impaired due to elevated fecal coliform
concentrations. As a result, in February 2002 the NC Department of Environment and Natural Resources
in coordination with Mecklenburg County Department of Environmental Protection developed a TMDL
report titled: Fecal Coliform Total Maximum Daily Load for the Irwin, McAlpine, Little Sugar and Sugar
Creek Watersheds, Mecklenburg County. This report addressed fecal coliform impairment by assigning
Ara\
NCGENR
N. C. Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 [phone] Customer Service
1 800 623-7748

load and wasteload allocations to sources within the watershed. Among the sources receiving wasteload
allocations are the CMUD facilities under discussion. Any additional flow at these facilities will be
subject to both the effluent limits set forth in the existing NPDES permit and the wasteload allocation(s)
set forth in the TMDL report.
We appreciate the opportunity to work with you on this proposal. If you have questions concerning any
of the above items, please feel free to contact me at [phone], extension 552.
Sincerely,
Brian Jacobson
DWQ, Modeling and TMDL Unit
CC: Jacqueline Jarrell, P.E., CMUD
Ronald Weathers, P.E., CMUD
Dave Goodrich, NC DENR
Jackie Nowell, NC DENR
Alex Marks, NC DENR
Michelle Woolfolk, NC DENR
EVA
NCDENR
N. C. Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 [phone] Customer Service
1 800 623-7748

Total Phosphorus reductions necessary at CMUD WWTPs to abide by the NC-
DWQ/CMUD/SC DHEC settlement agreement
Permitted Flow under current conditions (as per settlement agreement)
Units
McAlpine
(NC0024970)
Sugar
(NC0024937)
Irwin
(NC0024945)
Permitted monthly ave flow
MGD
64 •
20
15
12-month rolling average
lbs/day
534
292
Average concentration
mg/L
1.00
1.00
Monthly average (mass cap)**
lbs/day
1067
334
250
Average concentration**
mg/L
2.00
2.00
2.00
** At the Sugar and Irwin Creek plants, the mass caps only come into effect if construction
activites are pursued at each plant
Scenario 1 Expansions: McAlpine Creek from 64 to 80 MGD, Sugar from 20 to 25 MGD,
Irwin from 15 to 20 MGD
Units
McAlpine
(NC0024970)
Sugar
(NC0024937)
Irwin
(NC0024945)
Permitted monthly ave flow
MGD
80
25
20
12-month rolling average
lbs/day
534
292
Average concentration
mg/L
0.80
0.78
Monthly average (mass cap)**
lbs/day
1067
334
250
Average concentration**
mg/L
1.60 •
1.60
1.50
Scenario 2 Expansions: McAlpine Creek from 64 to 80 MGD, Sugar from 20 to 30 MGD
Units
McAlpine
(NC0024970)
Sugar
(NC0024937)
Irwin
(NC0024945)
Permitted monthly ave flow
MGD
80
30
15
12-month rolling average
lbs/day
534
292
Average concentration
mg/L
0.80
0.78
Monthly average (mass cap)**
lbs/day
1067
334
250
Average concentration**
mg/L
1.60
1.33
2.00
Scenario 3 Expansions: McAlpine Creek from 64 to 80 MGD, Irwin from 15 to 25 MGD
Units
McAlpine
(NC0024970)
Sugar
(NC0024937)
Irwin
(NC0024945)
Permitted monthly ave flow
MGD
80
20 •
25
12-month rolling average -
lbs/day
534
292
Average concentration
mg/L
0.80
0.78
Monthly average (mass cap)**
lbs/day
1067
334
250
Average concentration**
_ mg/L
1.60
2.00
1.20

•
CHARLOTTE.
July 30, 2003
Mr. Dave Goodrich
NCDENR
PO Box 29535
512 N. Salisbury St
Raleigh, NC 27626-0535
Subject: Request for Speculative Limits
McAlpine Creek WWTP
Sugar Creek WWTP
Irwin Creek WWTP
Dear Dave:
Charlotte -Mecklenburg Utilities requests issuance of speculative NPDES permit limits
for an increase in the treatment capacity and discharge of McAlpine Creek WWTP, Irwin
Creek WWTP, and/or Sugar Creek WWTP. Based on recently completed population and
flow projections there is a need for an additional 25 — 30 MGD of capacity before the
year 2020 in the Sugar/Irwin/McAlpine service area. DWQ has directed that requests for
speculative limits should be limited to no more than two options at two locations.
However, given the complexity and inter -relationship of these three plants, we believe it
is appropriate to explore three scenarios that will be needed in the subsequent engineering
alternatives analysis. With that in mind, please consider the following scenarios:
Scenario 1 -
Scenario 2 -
Scenario 3 -
Expand McAlpine Creek from 64 MGD to 80 MGD and
Expand Sugar Creek from 20 MGD to 25 MGD and
Expand Irwin Creek from 15 MGD to 20 MGD
(total increase = 26 mgd)
Expand McAlpine Creek from 64 MGD to 80 MGD and
Expand Sugar Creek from 20 MGD to 30 MGD
(total increase = 26 mgd)
Expand McAlpine Creek from 64 MGD to 80 MGD and
Expand Irwin Creek from 15 MGD to 25 MGD
(total increase = 26 mgd)
Administrative Division 5100 Brookshire Blvd. Charlotte, NC 28216 Phone: [phone] Fax: [phone]
Charlotte -Mecklenburg Utilities

We are prepared to assist with water quality modeling and/or other work that may be
required for the proper determination of speculative limits at these locations. Please
advise us as soon as possible as to how we can assist and as to a projected timeline for
development of the limits.
Finally, we realize that these treatment plants discharge into streams that are 303(d) listed
as impaired due to fecal coliform and/or turbidity. Fecal coliform TMDL's have been
developed and approved for these streams. Strategies have been identified and will be
implemented to mitigate coliform loading from increased WWTP discharges. WWTP
discharges do not directly contribute to elevated turbidity. However, secondary impacts
of WWTP expansion may or may not be a contributing factor. Secondary impacts will be
addressed in either an environmental assessment or environmental impact statement that
will be prepared after speculative limits are issued. This is all to say that the 303(d)
status of the receiving streams should not preclude the issuance of speculative limits.
We look forward to your response.
Sincerely,
CY:5) A30JV
Barry G llet
Deputy Director
Charlotte -Mecklenburg Utilities
cc: Rex Gleason
Rusty Rozzelle
File
BG/mmc