NC0036277_Speculative Limits_20030317

WDES DOCYNENT SCANNINO COVER SHEET
NPDES Permit:
NC0036277
McDowell Creek WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
March 17, 2003
This docuaxient is printed on reuse paper - ignore any
content on the reirex-6e side

i
k)fIh
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan Klimek, P.E., Director
Division of Water Quality
March 17.2003
Mr. Barry Gullet, Deputy Director
Charlotte Mecklenburg Utilities
5100 Brookshire Blvd.
Charlotte, North Carolina 28216
Subject: Speculative Discharge Limits
CMU McDowell Creek WWTP
NPDES Permit NCO036277
Dear Mr. Gullet:
This letter is in response to your request for speculative limits for an expansion of discharge flow from the McDowell
Creek Wastewater Treatment Plant, from the current permitted flow of 6.0 MGD to phased expansions of 6.6, 9, 12,
and 15 MGD. We have reviewed the request as well as modeling efforts conducted by the City/Consultant, and
provide the following comments.
The speculative limits presented here are based on our understanding of the proposal and of present environmental
conditions. The Division of Water Quality (DWQ) cannot guarantee that it will issue the City an NPDES permit to
discharge additional treated wastewater into waters of the State. Nor can we guarantee that the effluent limitations and
other requirements included in any permit will be exactly as presented here. Final decisions on these matters will be
made only after the Division receives and evaluates a formal permit application for the City's proposed discharge.
Environmental Assessments of New Projects
Please be aware that you will have to evaluate this project for environmental impacts before receiving a modified
permit. Anyone proposing to construct new or expanded waste treatment facilities using public funds or public (state)
lands must first prepare an environmental assessment (EA) when wastewater flows (1) equal or exceed 0.5 MGD or
(2) exceed one-third of the 7Q10 flow of the receiving stream. DWQ will not accept a permit application for a project
requiring an environmental assessment until the Division has approved the EA and sent a Finding of No Significant
Impact (FONSI) to the state Clearinghouse for review and comment.
An Environmental Assessment should contain a clear justification for the proposed project. It should provide an
analysis of potential alternatives, including a thorough evaluation of non -discharge alternatives. Nondischarge
alternatives or alternatives to expansion, such as spray irrigation, water conservation, or inflow and infiltration
reduction, are considered to be environmentally preferable to a surface water discharge. In accordance with the North
Carolina General Statutes, the preferred alternative must be the practicable waste treatment and disposal alternative
with the least adverse impact on the environment. If the EA demonstrates that the project may result in a significant
adverse effect on the quality of the environment, you must then prepare an Environmental Impact Statement. Alex
Marks of the Water Quality Planning Branch can provide you further information regarding the requirements of the
N.C. Environmental Policy Act. You can contact Mr. Marks directly at [phone], ext. 555.
Total Nitrogen and Total Phosphorus
The facility currently has limits for total nitrogen (10 mg/1) and total phosphorus (1 mg/1) at 6 MGD. Using the
Bathtub model of Mountain Island Lake and McDowell Creek Cove developed by Black & Veatch for Charlotte
Mecklenburg Utilities, DWQ ran scenarios for phased expansion limits of total nitrogen and total phosphorus. The
modeling endpoint was to have 10% or less of the predictions exceed the chlorophyll -a water quality standard of 40
ug(L. Since there is some question about the effect of the Huntersville Ordinance on nonpoint source loading,
particularly in the near term, DWQ used the model results that included some increase in nonpoint source loading.
N. C. Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 [phone]
Customer Service 1 800 623-7748
YA
rNMENR

CMU-McDowell Creek WWTP
NC0036277
Speculative Letter
Attachment I provides the speculative limits for the phased expansions. At 9 MGD, substantial reductions in nutrient
load will be required. Specifically, DWQ recommends nutrient loading of 450 lbs./day total nitrogen and 22 lbs./day
total phosphorus. At 12 MGD, due to the increased flow, the model predicts that an increase in the total phosphorus
load to 27 Ibs/day is permissible. At 15 MGD, the Division wishes to reserve issuance of speculative limits, since the
impact of nonpoint source loading is both greater and more uncertain. Current model results for 15 MGD indicate a
nutrient load of 450 lbs./day total nitrogen and approximately 31 to 35 IbsJday total phosphorus, depending on the
level of nonpoint source loading, in order to meet the chlorophyll -a endpoint. DWQ recommends continuation of the
water quality monitoring in Mountain Island Lake and McDowell Creek Cove, as well as monitoring of the nutrient
loading from the McDowell Creek watershed. These data would improve predictions from the Bathtub model for
speculative limits at 15 MGD, closer to the time when that expansion would be necessary.
Other Parameters
Speculative limits for BOD (CBOD) and ammonia are based on best available technology. Speculative limits for TSS
and fecal coliform bacteria are based on Charlotte Mecklenburg Utilities projections of future treatment capability.
Additional parameters will be evaluated after receipt of the permit modification request.
If you have questions about the speculative limits, please contact Chris Roessler at [phone], ext. 506, or Tom
Belnick at [phone], ext. 543.
IA'S'dwel.
David A. Goodrich
NPDES Unit Supervisor
cc: Mr. David Parker, Black & Veatch
Mooresville Regional Office, Water Quality Section
Central Files
NPDES Unit Files
Modeling & TMDL Unit Files
Alex Marks, DWQ

[Fwd: Roessler memo 3-13-03.docl
Subject: [Fwd: Roessler memo 3-13-03.doc]
Date: Thu, 13 Mar 2003 15:44:06 -0500
From: Chris Roessler <[e-mail]>
To: Dave Goodrich <[e-mail]>, Tom Belnick <[e-mail]>
Tom and Dave-> Attached you'll find the memo from B & V. Basically,
they do the additional modeling while considering no NPS load increase.
Rusty Rozelle later told Michelle that there are a lot of grandfathered
developments in the area. She is adamant that the model includes NPS
increases.
They also are concerned about antibacksliding so they request the same
loads at 9 MGD, as they would have at 12 MGD, when they would
meet the criterion with no NPS increase. This translates into Chl
criterion exceedances of 12.65% (with NPS inc.) and 11.9% (no NPS inc.)
at 9 MGD. Also, at 12 MGD, it means exceedances of 11.1 % with an
NPS increase. It's kind of funny that they do allow higher phosphorus
loading at 15 MGD (27 lb/day to 33.8 lb/day, though the same conc.).
This yields exceedance frequencies of 11.85% with NPS inc. and meets
the criterion without NPS inc.
Michelle prefers seasonal averaging, then monthly averaging, followed
by annual load averaging in the permit. I told her about your confusion
with that Tom - you might try to catch her this afternoon or Monday
AM (will be out otherwise) if you want to change her mind.
Chris
"Parker, David M. (Dave)" wrote:
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BLACK & VEATCH INTERNATIONAL COMPANY
MEMORANDUM
Charlotte -Mecklenburg Utilities
McDowell Creek WWTP
Speculative Limits and Water Quality Modeling
To: Chris Roessler & Michelle Woolfolk
From: Dave Parker and Beth Quinlan
B&V Project 97057.200
B&V File F
March 13, 2003
As we discussed during the conference call on Monday, the water quality criterion for chlorophyll
a is 40 ug/L, not be exceeded more than 10 percent of the time. You presented the results of
some additional model runs to estimate concentrations/loads of TN and TP that could be
discharged by the WWTP to achieve the 10 % exceedance rate.
The Huntersville ordinance was also discussed. Rusty Rozzelle stated that the ordinance was
adopted and was in effect. Although there were some developments already approved that
would not be subjected to the ordinance all other development would have to comply with the
ordinance requirements. He also stated that Mecklenburg County DEP had purchased land and
was planning to install BMPs in the watershed to alleviate some of the existing runoff problems.
Chris, you presented load numbers that corresponded to exceedances ranging from about 8.2 %
to 9.8 %. While this is a small difference in terms of the number of times that the criterion would
be exceeded, we feel it could represent a significant difference in the required WWTP
performance. We have therefore made additional model runs to establish the load limits more
precisely. Many iterations of the model were made to determine the load of TN and TP that the
WWTP could discharge while achieving the 10 % target. The attached Table lsummarizes these
runs. Note also that all of these runs were made assuming that the existing NPS loads are used
for future flowrates, thus taking credit for the improvements that are expected due to the new
Huntersville water quality regulations. As these regulations are in effect and being enforced, we
feel it is appropriate to include the effect of these regulations in the modeling. If you recall, Rusty
Rozelle even stated in our conference call that the county had purchased some land and was
planning some artificial wetlands to help address some current problems.
Figure 1 below compares concentrations that would be required to meet the same load condition
and the 10 % target. In this figure it was assumed that the ratio of TN to TP is 10, as it is now. At
9 mgd the difference is large, TN = 6.7 mg/L for the same load condition versus TN = 4.4 for the
10 % condition. As you can see, when we get to about the 15 mgd flowrate the 2 numbers are
much closer, TN = 4 mg/L for the same load condition, versus TN = 3.3 mg/L for the 10 % target
condition. Projecting out to a future condition of 24 mgd flow, the same load condition actually is
more restrictive than that required to meet the 10% target.
Figure 2 below shows plots of the combinations of TN and TP that could be used to achieve the
10 % target. For each flowrate the values along the curve provide the same results in the cove.
The point at the corner of the wedge represents the "same load" point. Therefore, the curve for
each flowrate extends between the values that represent the concentration limits for the same
load condition. For example, at 12 mgd, concentrations of TN = 5mg/L and TP = 0.5 mg/L
provides the same load as currently permitted. To achieve the 10 % target and to keep TN = 5
mg/L, TP would have to be 0.27 mg/L. Similarly, to keep TP = 0.5 mg/L, TN would have to be 3.1
mg/L. Several other options, such as TN = 4.5 mg/L with TP = 0.3 mg/L or TN = 4.0 mg/ with TP
= 0.35 mg/L also work

BLACK & VEATCH INTERNATIONAL COMPANY
MEMORANDUM Page 2
Charlotte -Mecklenburg Utilities B&V Project 97057.200
McDowell Creek WWTP March 13, 2003
Speculative Limits and Water Quality Modeling
Finally, the attached Table 1 presents calculations of loads that could be used to meet the 10 %
target based on our iterations of the model. We have also evaluated the treatment ability at the
wastewater plant, and identified in the table the combinations of TN and TP limits that we would
prefer to meet.- The higher TN and lower TP combinations are preferred by CMU as limits to be
met.
We are requesting that the mass load for the 12 mgd permit limits be used for the 9 mgd capacity.
As was mentioned in our conference call on Monday, we are concerned that there are some
outside interests that could try to enforce not increasing the mass load permitted at 9 mgd, even
though the modeling predicts that a higher mass load will be acceptable for the 12 mgd flows.
We think this can be justified because as we have discussed, the plant will operate at flows
between 6 and 9 mgd for the duration of the 9 mgd permit, at significantly less than 9 mgd for the
majority of, the time. Furthermore, the plant will berated at 12 mgd and regulated by the NPDES
limits for the 12 mgd plant before flows ever reach 9 mgd.
One final note — Barry Gullet originally requested that these nutrient limits be designated as mass
load limits on a 12 month rolling average. You noted in our conference call that you would
probably require monthly limits for the growing season, but that you might allow a rolling average
for the non -growing season. We would request this be allowed also, and that for the non -growing
season the mass limit still be written as a 12 month rolling average.
Please contact us if you have any questions about this information. Thanks for your continued
efforts on this.
Cc: Barry Gullet
Jackie Jarrell
Rusty Rozelle

It
BLACK & VEATCH INTERNATIONAL COMPANY
MEMORANDUM Page 3
Charlotte -Mecklenburg Utilities B&V Project 97057.200
McDowell Creek WWTP March 13, 2003
Speculative Limits and Water Quality Modeling
Table 1
TN and TP Load Calculations for Future Flows
i
Flowrate
TN TP
TN
TP
mgd
m L mg/L
lb/day
lb/day
Notes
6
10.0 1.00
500.3
50.0
Current Permitted Loads
Provides same load but exceeds 10%
9
6.7 0.67
500.3
50.0
target
9
6.7
0.29
500.3
21.8
Meets 10 % target
9
5.4
0.35
405.2
26.3
Meets 10 % target
9
4.7
0.42
352.7
31.5
Meets 10 % target
9
4.0
0.51
300.2
38.3
Meets 10 % target
9
3.4
0.67
255.1
50.3
Meets 10 % target
Same load as 12 mgd proposed limits to
9
6.7
0.36
500.3
27.0
meet 10% target at 12 mgd
Provides same load but exceeds 10%
12
5.0
0.50
500.3
50.0
target
27.0 ""
Meets 10 % target
12
5.0
0.27
500.3
12
4.5
0.30
450.3
30.0
Meets 10 % target
12
4.0
0.35
400.2
35.0
Meets 10 % target
12
3.5
0.42
350.2
42.0
Meets 10 % target
12
3.1
0.50
310.2
50.0
Meets 10 % target
Provides same load but exceeds 10%
15
4.0
0.40
500.3
50.0
target
33.8 '`
Meets 10 % target
15
4.0
0.27
500.3
15
3.6
0.30
450.3
37.5
Meets 10 % target
15
3.2
0.35
400.2
43.8
Meets 10 % target
15
2.9
0.40
362.7
50.0
Meets 10 % target
*Loads and concentrations requested for NPDES permit limits.

BLACK & VEATCH INTERNATIONAL COMPANY
MEMORANDUM
Charlotte -Mecklenburg Utilities
McDowell Creek WWTP
Speculative Limits and Water Quality Modeling
Figure 1
12
10
2
v
Page 4
B&V Project 97057.200
March 13, 2003
WWTP Nutrient Concentrations
6 9 12 15 18 21 24
mgd
® Same Load
❑ 10 % Exceedance

C
BLACK & VEATCH INTERNATIONAL COMPANY
MEMORANDUM
Page 5
Charlotte -Mecklenburg Utilities B&V Project 97057.200
McDowell Creek WWTP March 13, 2003
Speculative Limits and Water Quality Modeling
Figure 2
TN vs TP options
8.0
7.0
6.0
5.0
9 mgd
-=-12 mgd
E 4.0 -i-15 mgd
z 3.0 g
-=-18 mgd
2.0
1.0
0.0
0.00 0.20 0.40 0.60 0.80
TP (mg/L)

CMU-McDowell Creek WWTP
NCO036277
Speculative Letter
Attachment 1. Speculative Discharge Limits
Parameter
6.0 MGD
6.6 MGD
9.0 MGD
12.0 MGD
(Current Flow)
CBOD
5.0 mg/L
4.2 mg/L
4.2 mg/L
4.2 mg/L
(Summer)
(BOD)
CBOD
10 mg/L
8.3 mg/L
8.3 mg/L
8.3 mg/L
(Winter)
(BOD)
Total Suspended
30 mg/L
15 mg/L
12 mg/L
9 mg/L
Residue
NH3
2.0 mg/L
1.0 mg/L
1.0 mg/L
1.0 mg/I
(Summer)
NH3
2.5 mg/L
1.0 mg/L
1.0 mg/L
1.0 mg/L
(Winter)
Fecal Coliform
200/100 mL
100/100 mL
100/100 mL
100/100 mL
Total Nitrogen
10 mg/L
450 lbs./day
450 lbs./day
450 lbs./day
(Summer)
Total Nitrogen
10 mg/1
500 tbs./day
500 lbs./day
500 lbs./day
(Winter)
Total Phosphorus
1.0 mg/L
35 lbs./day
22 lbs./day
27 lbs./day
(Summer)
Total Phosphorus
1.0 mg/1
401bs./day
27 lbs./day
32 lbs./day
Winter)
TJX 859, �b gq 90
Notes:
1. Summer = (April to October) and Winter = (November to March).
2. For TN, summer monthly average mass limit equates to 8.1 mg/l (at 6.6 MGD); 6.0 mg/l (at 9 MGD); and 4.5 mg/l (at 12 MGD).
3. For TN, winter monthly average mass limit equates to 9.0 mg/l (at 6.6 MGD); 6.6 mg/l (at 9 MGD); and 5.0 mg(l (at 12 MGD).
4. For TP, summer monthly average mass Omit equates to 0.64 mgA (at 6.6 MGD); 0.29 mgtl (at 9 MGD); and 0.27 mg/l (at 12 MGD).
5. For TP, winter monthly average mass Omit equates to 0.73 mg/l (at 6.6 MGD); 0.36 mg/l (at 9 MGD); and 0.32 mg/l (at 12 MGD).

Comparison of spec limits for McDowell Creek in Feb 02 Black & Veatch versus Feb 03 letter from Mecklenburg Co.
2/28/03 Report issued in Feb/02, Letter sent in Feb/03
WWTP
Capacity
(MGD)
Limits TP
TN
based on monthly avg
based on 12-month rolling avg
these limits used in model
Report
Letter
Letter
Cone. (mg/L) Load (lbs/day)
Cone. (mg/L) Load (lbs/day)
Cone. (mg/L) Load (lbs/day)
6
1
50
1
50
1
50
10
500
10
500
10
500
6.6
1
55
1.82
100
0.91
50
10
550
18.17
1000
9.08
500
9
1
75
1.33
100
0.67
50
10
750
13.32
1000
6.66
500
12
0.65
65
1.00
100
0.50
50
6.5
650
9.99
1000
5.00
500
15
0.65
81
0.80
100
0.40
50
6.5
810
7.99
1000
4.00
500
24
0.4
80
0.50
100
0.25
50
4
8001
5.00
1000
2.50
500
Chi a
Chl a
Frequency of Chi a
growing season avg.
growing season avg.
over 40 ug/L (%)
Report
Letter
Cone. (ug/L) _
_Cone. (ug/L)
29.8
29.8
21.6
31.3
29.4
21
37.1
28.2
19.2
31.8
26.8
17
35.5
25.8
15.4
30.8
23
11.4
Note: calculated numbers are in italics Is'sj kvk
Observed growing season chlorophyll averages (ug/L) at McDowell Creek Cove `F
used Apr -Oct if available
mean median
geomean
apr
may
june
july
august
sept Oct
1997
48.4 35
32.7
6
35
122
50
29
1998
34.8 32
29.3
9
32
62
28
43
1999
20.7 20.5
19.0
8
32
26
22
17
19
2000
33.2 26.0
28.8
14
75
24
28
34 24
2001
29.2 20
23.9
11
68
29
20
18
2002
21.3 23.5
16.2
1
17
21
26
31
31 2
all years 31.3 24.8 24.2
�W A4,14 40��
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W

Comparison of different spec limits for McDowell Creek WWTP expansion
2/28/03
WWTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load (Ibs/day)
avg Chi a
freq. > 40 ug/L
ug/L
%
6
1
50
29.8
21.6
10
500
6.6
0.91
50
29.4
21
9.08
500
6.6
0.67
36.9
24.3
13.2
6.66
367
6.6
0.73
40
25.7
15.2
7.27
400
9
0.67
50
28.2
19.2
6.66
500
9
0.50
37.5
23.8
12.6
5.00'
375
9
0.0
40
24.6
13.7
5.33
400
9
rt
0.47
35
23
11.5
4.70
350
VVVVTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load_(Ibs/day)
avg Chi a
freq. > 40 ug/L
ug/L
%
12
0.50
50.
26.8
17
5.00
500
12
0.40
40
23.5
12.2
4.00 .
400
--
12
0.35
35
21.9
10 4
3.50
350
i
15
0.40
50
25.8
15.4
4.00
500
15
0.25
31.3
20
7.71
2.50
313
15
0.32
40
22.7
11.1
3.2
400
15
0.28
35
21.2
9.1
2.80
350
24
0.25
50
23
11.4
2.50
500
24
0.2
40
20.4
8.2
2
400

Comparison of different spec limits for McDowell Creek WWTP expansion including no increase in NPS loading per Huntersville ordinance
2/28/03
WWTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load (lbs/day)
avg Chi a
freq. > 40 ug/L
ug/L
%
6
1
50
29.8
21.6
10
500
6.6
0.91
50
29.3
20.9
9.08
500
6.6
0.67
36.9
6.66
367
6.6
0.73
40
25.55
15.1
7.27
400
9
0.67
50
6.66
500
27.8
18.5
9
0.50
37.5
5.00
375
9
0.53
40
24.2
13.1
5.33
400
9
0.47
35
22.5
10.8
4.70
350
WWTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load (lbs/day)
avg Chi a
freq. > 40 ug/L
ug/L
%
12
0.50
50
26
15.7
5.00
500
12
0.40
40
23.5
12.2
4.00
400
12
0.35
35
21
8.85
3.50
350
15
0.40
50
24.5
13.5
4.00
500
15
0.25
31.3
2.50
313
15
0.32
40
22.65
11
3.2
400
15
0.28
35
19.8
7.4
2.80
350
24
0.25
50
20.8
8.65
2.50
500
24
0.2
40
18.2
5.7
2
400

Re: model rtms
Subject: Re: model runsUM(
Date: Sun, 09 Mar 2003 11:35:09 -0500
From: Dave Goodrich <[e-mail]>
To: Chris Roessler <[e-mail]>
CC: Michelle Woolfolk <[e-mail]>,
Tom Belnick [e-mail]>, Boyd Devane <[e-mail]>
It seems as though the 350 lbs/day (TN) and 28 lbs/day (TP) numbers are appropriate.
If you also could
pass on that Boyd told me that it was ok for CMUD to go to 6.4 MGD without applying
SEPA, I'd appreciate
that. It's doubtful that I'll be involved in the conference call.
Chris - Thanks for all of your work on this
Chris Roessler wrote:
> Hey all-> Thanks for meeting twice today. The additional model
> runs you asked for are in the attached spreadsheet (the last
> worksheet to the right - scenario grid). There
> definitely could be some debate about what the right limits
> should be. Do you get to 10 exactly and stop there?
> Have a look and a good weekend. Chris
--
> Name: McDowell spec limits_022802.xls
> McDowell spec limits_022802.xls Type: Microsoft Excel Worksheet
(applicationlvnd.ms-excel)
> Encoding: base64
> v� GMJU /T�Q� Download Status: Not downloaded with message
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Comparison of spec limits for McDowell Creek in Feb 02 Black & Veatch versus Feb 03 letter from Meckkurg'Co.
2/28/03 Report issued in Feb/02, Letter sent in Feb/03
WWTP
Capacity
Limits
TP
TN
based on monthly avg
based on 12-month rolling avg
these limits used in model
(MGD)
Report
Letter
Letter
Conc. (mg/L)
Load (Ibs/day)
Conc. (mg/L) Load (Ibs/day)
Conc. (mg/L)
Load (Ibs/day)
6
1
50
1
50
1
50
10
500
10
500
10
500
R,
:�!�
6.6
1
55
1.82
100
0.91
50
10
550
18.17
1000
9.08
500
9
1
75
1.33
100
0.67
50
10
750
13.32
1000
6.66
500
12
0.65
65
1.00
100
0.50
50
6.5
650
9.99
1000
5.00
500
15
0.65
81
0.80
100
0.40
50
6.5
810
7.99
1000
4.00
500
24
0.4
80
0.50
100
0.25
50
4
8001
5.00
1000
2.50
500
Note: calculated numbers are in italics
Chl a
Chl a
growing season avg.
growing season avg.
Report
Letter
Conc. (ug/L)
Conc. (ug/L)
29.8
29.8
31.3
29.4
37.1
28.2
31.8
26.8
35.5
25.8
30.8
23
> Zj � MCOEP dafn � laaf
5 14, 1 dir"O V4,
4N2�Svr�L,-6
J� Gx/'*wh s+tIr.
Kra owe �w)

Comparison of different spec limits for McDowell Creek WWTP expansion including no increase in NIPS loading per Huntersville ordinance
Using relatively higher N loads
WWTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load (lbs/day)
avg Chi a
freq. > 40 ug/L
u /L
%
6
1
50
29.8
21.6
10
500
6.6
0.91
50
29.3
20.9
9.08
500
6.6
0.67
36.9
500
6.6
0.73
40
27.6
18.1
500
9
0.67
50
6.66
500
27.8
18.5
9
0.50
37.5
6.66
500
9
0.53
40
26.1
15.9
6.66
500
9
0.47
35
25.2
14.6
6.66
500
WWTP
Limits
TP-
Capacity
TN
(MGD)
Conc. (mg/L) Load (lbs/day) avg Chi a
freq. > 40 ug/L
ug/L
%
12
0.50
50
26
15.7
5.00
500
12
0.40
40
24.4
13.45
5.00
500
12
0.35
35
23.5
12.15
5.00
500
15
0.40
50
25.8
15.4
4.00
500
15
0.32
40
22.2
10.4
3.60
450
15
0.32
40
23
11.45
4.00
500
15
0.28
35
22.110.3
4.00
500
E
24
50
20.8
8.65
2.50
0
V1
0.2
40
50

Comparison of different spec limits for McDowell Creek WWTP expansion
2/28/03 Using relatively higher N loads NPS increases included in these runs
WWTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load (lbs/day)
avg Chi a
freq. > 40 ug/L
ug/L
%
6
1
50
29.8
21.6
10
500
6.6
0.91
50
29.4
21
9.08
500
6.6
0.67
36.9
9.08
500
6.6
0.73
40
27.7
18.3
9.08
500
9
0.67
50
28.2
19.2
6.66
500
9
0.50
37.5
6.66
500
9
0.53
40
26.6
16.6
6.66
500
9
0.47
35
25.7
15.3
6.66
500
WWTP
Limits TP
Capacity
TN
(MGD)
Conc. (mg/L) Load (Ibs/day)
avg Chi a
freq. > 40 ug/L
u /L
%
12
0.50 50
26.8
17
5.00 500
12
0.40 40
25.3
14.7
5.00 500
12
0.35 35
24.4
13.43
5.00 500
15
0.40 50
24.5
13.5
4.00 500
15
0.32 40
23.6
12.2
3.60 450
15
0.32 40
24.4
13.35
500
15
0.28 35
23.5
12.2
500
24
0.2 50
8.65
. 0 500
24
0.2 0
500

Avg Chi a / Freq. of Standard exceedances
NPS increases
6.6 MGD
TP
500 / 9.08
400 / 7.27
367 / 6.66
TN
50/0.91
29.3/20.9
40/0.73
27.7/18.3
25.7/15.2
36.9 / 0.67
1
1
124.3 / 13.2
9 MGD
TP
500 / 6.66
400 / 5.33
375 / 5.00
350 / 4.70
TN
50 / 0.67
28.2 / 19.2
40 / 0.53
26.6 / 16/6
24.6 / 13.7
37.5/0.50
23.8/12.6
35 / 0.47
25.7 / 15.3
23 / 11.5
12 MGD
TP
500 / 5.00
400 / 4.00
350 / 3.50
TN
50/0.50
26.8/17
4010.40
25.3 / 14.7
23.5 / 12.2
35/0.35
24.4/13.4
21.9/10
15 MGD
TP
500 / 4.00
450 / 3.60
400 / 3.20
350 / 2.80
TN
50 / 0.40
25.8 / 15.4
40/0.32
24.4/13.35
23.6/12.2
22.7/11.1
35/0.28
123.5/12.2
1.2/9.1
NPS does not increase
6.6 MGD
TP
500 / 9.08
400 / 7.27
367 / 6.66
TN
-
50/0.91
29.3/21.6
40 / 0.73
27.6 / 18.1
25.55 / 15.1
36.9 / 0.67
9 MGD
TP
500 / 6.66
400 / 5.33
375 / 5.00
350 / 4.70
TN
50/0.67
27.8/18.5
40/0.53
26.1/15.9
242/13.1
37.5 / 0.50
35/0.47
25.2/14.6
22.5/10.8
12 MGD
TP
500 / 5.00
400 / 4.00
350 / 3.50
TN
50 / 0.50
26 / 15.7
40 / 0.40
1
124.4 / 13.45
23.5 / 12.2
35/0.35
1
123.5/12.15121/8.8511
15 MGD
TP
500 / 4.00
450 / 3.60
400 / 3.20
350 / 2.80
TN
50/0.40
24.5/13.5
22.2/10.4
40 / 0.32
23 / 11.45
22.65 / 11
35 / 0.28
122.1/10.3
19.8/7.4
IF

Avg Chl a / Freq. of Standard exceedances
NPS increases
6.6 rAGD.,
500 / 9.08
400 / 7.27
367 / 6.66
50/0.91
29.3/20.9
40 / 0.73
1
127.7118.3
125.7 / 15.2
36.9 / 0.67
24.3 / 13.2
9 MGD
1-�rJ
500 / 6.66
400 / 5.33
375 / 5.00
350 / 4.70
T
50 / 0.67
28.2 / 19.2
40 / 0.53
26.6 / 16/6
24.6 / 13.7
37.5 / 0.50
23.8 / 12.6
35 / 0.47
25.7 / 15.3
ii1:
12 MGD
:I:Ll
500 / 5.00
400 / 4.00
350 / 3.50
50 / 0.50
26.8 / 17
40/0.40
25.3/14.7
23.5/12.2
'
35/0.35
124.4/13.4
121.9/10
15 MGD
500/4.00
450 / 3.60
400 / 3.20
350 / 2.80
50 / 0.40
25.8 / 15.4
`
40 / 32
24.4 / 13.35
23.6 / 12.2
22.7 / 11.1
35V 0.2
23.5/12.2
1
121.2/9.1
83�)
3
Zs�O Z
NPS does not increase
6.6 MGD
TP
500 / 9.08
400 / 7.27
367 / 6.66
TN
--
50/0.91
29.3/21.6
40 / 0.73
127.6 / 18.1
25.55 / 15.1
36.9 / 0.67
9 MGD
TP
500 / 6.66
400 / 5.33
375 / 5.00
350 / 4.70
TN
50/0.67
27.8/18.5
40/0.53
26.1 /15.9
24.2/13.1
37.5 / 0.50
35 / 0.47
25.2 / 14.6
2.510.
12 MGD
TP
500 / 5.00
400 / 4.00
350 / 3.50
TN
50 / 0.50
26 / 15.7
40 / 0.40
24.4 / 13.45
23.5 / 12.2
35/0.35
123.5/12.15
21 /8.85
15 MGD
TP
500 / 4.00
450 / 3.60
400 / 3.20
350 / 2.80
TN
50/0.40
24.5/13.5
22.2/10.4
40 / 0.32
23 / 11.45
22.65 / 11
35/0.28
122.1/10.3
1
19.8/7.4

Comparison of spec limits for McDowell Creek in Feb 02 Black & Veatch versus Feb 03 letter from Mecklenburg Co.
2/28/03 Report issued in Feb/02, Letter sent in Feb/03
WWTP
Capacity
(MGD)
Limits TIP
TN
based on monthly avg
based on 12-month rolling avg
these limits used in model
Report
Letter
Letter
Conc. (mg/L) Load (Ibs/day)
Conic. (mg/L)
Load (Ibs/day)
Conc. (mg/L) Load (lbs/day)
6
1
50
1
50
1
50
10
500
10
500
10
500
6.6
1
55
1.82
100
0.91
50
10
550
18.17
1000
9.08
500
9
1
75
1.33
100
0.67
50
10
750
13.32
-1000
6.66
500
12
0.65
65
1.00
100
0.50
50
6.5
650
9.99
1000
5.00
500
15
0.65
81
0.80
100
0.40
50
6.5
810
Z99
1000
4.00
500
24
0.4
80
0.50
100
0.25
50
4
8001
5.00
1000
2.50
500
Note: calculated numbers are in italics
Observed growing season chlorophyll averages (ug/L) at McDowell Creek Cove
Chi a
Chi a
Frequency of Chi a
growing season avg.
growing season avg.
over 40 ug/L (%)
Report
Letter
Conc. (ug/L)
Conc. (ug/L)
29.8
29.8
21.6
31.3
29.4
21
37.1
28.2
19.2
31.8
26.8
17
35.5
25.8
15.4
30.8
23
11.4
used Apr -Oct if available
mean median
geomean
apr
may
june
july
august
sept Oct
1997
48.4 35
32.7
6
35
122
50
29
1998
34.8 32
29.3
9
32
62
28
43
1999
20.7 20.5
19.0
8
32
26
22
17
19
2000
33.2 26.0
28.8
14
75
24
28
34 24
2001
29.2 20
23.9
11
68
29
20
18
2002
21.3 23.5
16.2
1
17
21
26
31
31 2
all years 31.3 24.8 24.2

Comparison of different spec limits for McDowell Creek WVVTP expansion
2/28/03
WWTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load (Ibs/day)
avg Chi a
freq. > 40 ug/L
u /L
%
6
1
50
29.8
21.6
10
500
6.6
0.91
50
29.4
21
9.08
500
6.6
0.67
36.9
24.3
13.2
6.66
367
6.6
0.73
40
25.7
15.2
7.27
400
9
0.67
50
28.2
19.2
6.66
500
9
0.50
37.5
23.8
12.6
5.00
375
9
0.53
40
24.6
13.7
5.33
400
9
0.47
35
23
11.5
4.70
350
C ��I z"I", 0, ( I C�
---3pl 41%, - 0 C,-r
/vi
WVVTP
Limits
TP
Capacity
TN
(MGD)
Conc. (mg/L)
Load (Ibs/day)
avg Chi a
freq. > 40 ug/L
u /L
%
12
0.50
50
26.8
17
5.00
500
12
0.40
40
23.5
12.2
4.00
400
12
0.35
35
21.9
10
3.50
350
15
0.40
50
25.8
15.4
4.00
500
15
0.25
31.3
20
7.71
2.50
313
15
0.32
40
22.7
11.1
3.2
400
15
0.28
35
21.2
9.1
2.80
350
24
0.25
50
23
11.4
2.50
500
24
0.2
40
20.4
8.2
2
400
r

Comparison of different spec limits for McDowell Creek WWTP expansion including no increase in NPS loading per Huntersville ordinance
2/28/03
WWTP
Limits
TP
Capacity
TN
(MGD)
Cone. (mg/L)
Load (lbs/day)
avg Chi a
freq. > 40 ug/L
ug/L
%
6
1
50
29.8
21.6
10
500
6.6
0.91
50
29.3
20.9
9.08
500
6.6
0.67
36.9
6.66
367
6.6
0.73
40
25.55
15.1
7.27
400
9
0.67
50
6.66
500
27.8
18.5
9
0.50
37.5
5.00
375
9
0.53
40
24.2
13.1
5.33
400
9
0.47
35
22.5
10.8
4.70
350
WWTP
Limits TP
Capacity
TN
(MGD)
Cone. (mg/L) Load (lbs/day)
avg Chi a
freq. > 40 ug/L
ug/L
%
12
0.50 50
26
15.7
5.00 500
12
0.40 40
23.5
12.2
4.00 400
12
0.35 35
21
8.85
3.50 350
15
0.40 50
24.5
13.5
4.00 500
15
0.25 31.3
2.50 313
15
0.32 40
22.65
11
3.2 400
15
0.28 35
19.8
7.4
2.80 350
24
0.25 50
20.8
8.65
2.50 500
24
0.2 40
18.2
5.7
2 400

0
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- �(4,d We,I��a—
CHARWITE.
February 27, 2003
Mr. David Goodrich
N.C. Division of Water Quality/NPDES Unit
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: McDowell Creek Wastewater Treatment Plant
NPDES Permit NCO036277
Dear Dave:
The purpose of this letter is to propose actions and a schedule for moving forward with the
expansion of the subject plant. As this project has been underway for several years, I need to
give you an update and some new information you may not have about the progress made to
date on this WWTP expansion, how the project fits into local efforts to protect Mountain
Island Lake, and why this project is a very high priority for Charlotte Mecklenburg Utilities.
In 1999, Utilities began work to expand the McDowell Creek WWTP. This plant serves the
rapidly growing areas of Huntersville, Cornelius, and Davidson. This plant discharges into
Mountain Island Lake which is the drinking water supply for much of Charlotte, Gastonia,
and Mount Holly. Charlotte Mecklenburg Utilities is committed to providing wastewater
management in a way that protects the quality of McDowell Creek and Mountain Island
Lake.
McDowell Creek WWTP serves a diverse and developing drainage basin comprising most of
northwest Mecklenburg County. Proposed light rail transit lines will run through the basin.
Increased development density along the transit corridor is linked to reducing urban sprawl,
reducing congestion, and improvements in air quality. Property along the shore of Lake
Norman is among the most valuable and sought after in the region, if not the state. A
combination of exclusive homes and multi -family housing continues to develop in that area.
Larger tracts of land in the basin are being developed into large, mixed -use developments
utilizing cutting -edge development methods to protect many types of environmental and
sprawl concerns.
As a result of these influences and growth, flows into McDowell Creek WWTP have
increased rapidly over the last several years. December 2002 flows averaged 5.6 mgd, the
maximum monthly average for 2002 and likely the max month value for this winter period.
The plant is currently permitted for 6.0 mgd. Please recall that Utilities currently has a series
of projects that are under construction or nearing construction that will remove 750,000 to
1,000,000 gpd of flow from McDowell. That flow will be treated at the Rocky River
Regional WWTP operated by the Water and Sewer Authority of Cabarrus County (WSACC).
Even with this reduction, it will be a significant challenge to expand McDowell Creek in time
to treat future projected flows.
Administrative Division 5100 Brookshire Blvd. Charlotte, NC 28216 Phone: [phone] Fax: [phone]
Charlotte -Mecklenburg Utilities

In February 2000, a stakeholder group was formed to help Utilities decide on the approach
that should be used for wastewater management in this environmentally sensitive basin. The
stakeholders represented property owners, the Sierra Club, Trust for Public Land, Mountain
Island Marine Commission, the three towns served by the plant, the real estate and building
industry, the Catawba RiverKeeper, NC DENR, nearby residents, and others. Utilities and
our consultant, Black & Veatch, provided support to the group in the form of population and
flow projections, alternatives for treating and managing wastewater generated in the basin,
and information about local water supply watershed protection ordinances already in place.
After more than six months of meetings, the group and Utilities reached a number of
conclusions including:
• Wastewater produced in the McDowell basin should not be exported from the
basin
• Advanced wastewater treatment at the McDowell Plant was preferable to
other alternatives
• Water quality in Mountain Island Lake must be protected
• Utilize treated effluent reuse to reduce the volume discharged to Mountain
Island Lake
Using this information and a goal of preserving water quality conditions, work was started on
a project to expand the plant incrementally from 6 mgd to 9, 12, and 15 mgd. Another
intermediate step is to re -rate the plant from 6.0 mgd to 6.6 mgd once a FONSI is achieved.
This re -rating takes advantage of existing capacity at the facility. The ultimate build out is
expected to be about 24 mgd, but this projection is subject to further refinement based on
recent changes to Huntersville's land use plans.
On June 5, 2000, Black & Veatch requested speculative limits for the expansion project on
behalf of Utilities. DENR staff told us that they needed help with modeling the water quality
impacts. Black & Veatch completed the extensive modeling and submitted a report to DENR
on May 9, 2001. There have been several question and answer exchanges between DENR
and our modelers over the past two years and 7 months, but no speculative limits have been
issued. The lack of speculative limits has stalled the plant expansion process significantly.
During this delay, we have completed every part of the project that we could, taking the risk
that our very conservative design would be adequate to satisfy the final permit requirements.
Black & Veatch has prepared a draft Environmental Assessment (except for the requested
speculative limits) that has undergone a completeness review by DENR, and the construction
plans and specifications for the project are 98% complete (on -hold pending permit limits).
We have actually purchased membrane micro filtration units to be used in the expansion
project. The Town of Huntersville, which comprises a majority of the McDowell watershed,
has adopted a new water quality ordinance that is designed to maintain existing water quality
in the creek and in Mountain Island Lake. The ordinance is based on low impact
development (LID) techniques and other requirements that will significantly alter the
development and growth of the Town. In addition, Utilities and Mecklenburg County have
continued to purchase critical parcels of land to be preserved for water quality protection and
open space in the basin.
Mecklenburg County and their consultants developed a separate watershed model that was
used as a tool in the development of the new Huntersville water quality ordinance. The

Black & Veatch model and the County model utilize different water quality base models.
Most importantly, however, both models show that water quality in McDowell Creek and
McDowell Cove are protected if the WWTP permit is issued based on the table shown below
and the land use and development requirements of the new Huntersville water quality
ordinance are in place. It would seem that this would be intuitive because the Huntersville
ordinance is designed to limit nutrient loads from non -point sources to the current level and
the proposed WWTP permit also limits the nutrient load to current permitted levels even as
the flow rates increase. It would seem that with more water coming through the stream and
cove and the same mass of nutrients as permitted now that water quality would improve.
Utilities believes that these two intensive and mostly independent modeling efforts provide a
strong basis for setting NPDES permit limits for the plant and that the environmental
assessment, along with the newly adopted Huntersville water quality ordinance, should result
in a finding of no significant impact due to plant expansion.
Utilities has evaluated the modeling results and the information described above and suggests
that DENR should consider issuing the speculative limits for McDowell Creek WWTP
shown in the table below. (All values shown are monthly averages unless indicated
otherwise.)
Flow
Existing
6.6 mgd
9.0 mgd
12.0 mgd
15.0 mgd
6.0 mgd)
CBOD*
5.0 mg/1
4.3 mg/1
4.3 mg/l
4.3 mg/1
4.3 mg/1
(Summer)
BOD
CBOD*
10.0 mg/1
8.6 mg/1
8.6 mg/l
8.6 mg/l
8.6 mg/l
(Winter)
(BOD
Total
30 mg/1
15 mg/1
12 mg/l
9 mg/l
6 mg/l
Suspended
Residue
NH3*
2.0 mg/l
1.0 mg/1
1.0 mg/l
1.0 mg/1
1.0 mg/l
Summer
NH3* Winter
2.5 mg/l
1.0 m
1.0 mg/l
1.0 m
1.0 mg/l
Fecal Coliform
200/100 ml
100/100 ml
100/100 ml
100/100 ml
100/100 ml
Total N
10.0 mg/l
500 lb/day
500 lb/day
5001b/day
500 lb/day
mass limit
mass limit
mass limit
mass limit
based on 12-
based on 12-
based on 12-
based on 12-
month rolling
month rolling
month rolling
month rolling
avg.
avg.
avg.
avg.
10001b/day
1000lb/day
1000lb/day
10001b/day
monthly avg
monthly avg
monthly avg
monthly avg
limit
limit
limit
limit
Total P
1.0 mg/1
50 lb/day mass
50 lb/day mass
50 lb/day mass
50 lb/day mass
limit based on
limit based on
limit based on
limit based on
12-month
12-month
12-month
12-month
rolling avg,
rolling avg,
rolling avg,
rolling avg,
1001b/day
100lb/day
1001b/day
100lb/day
monthly avg
monthly avg
monthly avg
monthly avg
limit
limit
limit
limit
*Proposed limits for CBOD and NH3 to be confirmed based on additional modeling of
McDowell Creek, currently underway. It had been assumed that DENR staff would do this
work, but to expedite the project Utilities has authorized our consultants to proceed with this.

Based on projected growth in flow to McDowell and the re -direction of flows to WSACC,
we need to achieve the very aggressive schedule shown below to avoid exceeding the
permitted capacity of McDowell Creek WWTP and to avoid any interruption of economic
development in that service area. Projected critical flow / capacity periods are shown in bold
italics.
Action Needed / Event
Needed lby
Comment
Speculative Limits issued
3/17/03
DENR action
EA completed, submit to DENR
3/31/03
B&V action
Process EA, draft FONSI
5/15/03
DENR action
Submit NPDESI permit
application
5/15/03
CMUD / B&V action
Final FONSI issued
7/15/03
DENR action
Process NPDES permit, issue
draft permit
7/15/03
DENR action
Submit plans & specs for ATC
7/30/03
B&V action
Final NPDES permit issued
8/1/03
DENR action
Review plans, issue ATC, re -rate
plant to 6.6 mgd
l l/1/03
DENR action
Max winter flows at plant
projected to exceed 6 mgd
Winter 2003104
OK if plant re -rated to 6.6 mgd
before wet winter weather
Advertise for bids
11/15/03
CMUD / B&V action
Contracts awarded, begin
construction
4/15/04
CMUD action
.75 — L0 mgd flow redirected to
WSACC
Spring/summer 04
Reduces flows for winter 04/05
so plant is compliant w/re-rating
to66mgd
Construction of components to
increase capacity to 9.0 mgd is
completed
12/2005
Provides enough capacity to
sustain flows until expansion to
12 mgd is completed.
Max month flows projected to
exceed 6.6 mgd
Winter 2005106
Dave, this is a very aggressive schedule from the standpoint of DENR actions and
construction scheduling. It also assumes that the public review periods do not generate any
unexpected issues that have not been adequately addressed. Utilities began this project in
1999 with a reasonable, realistic schedule that was driven by the projected flows and
customer needs. DENR was very aware of that schedule and of the capacity needs from their
participation in the stakeholders group and from discussions and correspondence that I have
had with you and others at DENR over the past two years. We understand the severe staffing
issues and budget issues that you continue to face and we have done as much of the work
needed for this process as we can to help expedite this project. We are now at a point where
delays have put the permitting process firmly on the critical path of the project and the plant
clearly in jeopardy of capacity shortfalls. Charlotte Mecklenburg Utilities believes that the
only way the capacity shortfalls can be avoided is for DENR to firmly commit to actions in
the table above in the time periods shown and to meet those commitments.
Utilities, our consultants, Mecklenburg County, and the Town of Huntersville have gone "the
extra mile" to gather data, project land use and development data, model the potential
impacts, and develop plans to mitigate them. The McDowell Creek WWTP expansion
project proposed is designed to far exceed requirements to protect Mountain Island Lake and

Huntersville's new zoning and water quality ordinances guard against secondary impacts
from storm water runoff. We are not aware of any reasons or lack of data that should prevent
DENR from taking immediate action to keep this project on track.
We look forward to meeting with you and Michelle Woolfolk and your staff on Monday,
March 3, 2003, at 10:00 to discuss the modeling and speculative limits. Please be prepared
to give us your commitment to meeting the project schedule at our meeting on Monday.
Sincerely,
CHARLOTTE MECKLENBURG UTILITIES
Barry M. ullet, PE
Deputy Director
C: Michelle Woolfolk
Rusty Rozzelle
Jackie Jarrell
Barry Shearin
Dave Parker
File

Meeting on McDowell Creej W WTPtA
w' U U
Subject: Meeting on McDowell Creek W WTP
Date: Mon, 27 Jan 2003 10:26:07 -0600
From: "Parker, David M. (Dave)" <[e-mail]>
To: "Tom Belnick ([e-mail])" <[e-mail]>
Tom,
Have you been able to find a time when we and CMU can meet with DWQ about
the McDowell Creek plant? I think you said that Dave Goodrich was pretty
busy related to a court case, but that he might have some time in early
February.
As a reminder, we want to meet to discuss the plans for expanding the
McDowell Creek plant. Flows have increased due to growth, and we want to
try to help out with the permitting process as much as we can. We have been
discussing water quality issues with Michelle Woolfolk and Chris Roessler,
and are also discussing some issues related to water quality modeling with
MCDEP. As it stands, we owe a response to Chris and Michelle, but we still
want to meet to discuss the project. Getting speculative limits is the
first critical step.
We have an EA drafted and ready to submit, and we think we have done a lot
to help mitigate any environmental consequences. We'd like to discuss this,
and get any initial reactions or responses to this.
We also have design documents ready to submit for the first phase of the
expansion. Again, we'd like to discuss what we've done and how we can help
with documentation etc. to ease the review process.
We would like to meet with Dave Goodrich, yourself, Chris, Michelle, and
possibly Todd Kennedy to discuss all of this. Our intent is to make sure we
are doing all that we can to complete the permitting process, and also
possibly make your jobs easier as you review our various submittals.
Let me know what you can work out. Thanks.
David M. Parker, P.E. \
Black & Veatch
8520 Cliff Cameron Drive, Suite 350
Charlotte, North Carolina 28269
Phone: [phone]
Mobile: [phone]
Fax: [phone]
E-mail: ParkerDMQbV.com
I of 1 1/27/03 4:29 PM

Re: CMUD - McDowell Cr. spec limits
Subject: Re: CMUD - McDowell Cr. spec limits
Date: Fri, 19 Jul 2002 13:46:04 -0400
From: Dave Goodrich <dave.goodrich @ncmail.net>
To: Chris Roessler <[e-mail]>
CC: Michelle Woolfolk <[e-mail]>,
Mike Myers <[e-mail]>, Tom Belnick <[e-mail]>
it
Chris -
Thanks for the update. If I'm remembering correctly, I thought that the Wylie model looked at<25 ug/L
being the target value for each model segment.
Also, she needs to run the model at permitted limits. She can make her argument and provide the results
from the alternate run, but she needs to provide inputs and outputs based on permitted limits as well.
Dave
Chris Roessler wrote:
Hi all-> I had a conference call yesterday with Dave Parker and Beth Quinlan,
who's the modeler for Black & Veatch that did the Mtn. Island Lake report.
I had several main concerns with the modeling:
1. The hydrology calibration didn't seem adequate. Many times the model
has the baseflow at zero while the observed flow was at 15-30 cfs. The
report said that the emphasis was on calibrating storm flows. In the real
world, I don't think this is good since many of the high chlorophyll events
occur during lower flow (less dilution).
2. Their watershed model, P8, apparently only reports nitrogen loading as
TKN, while Bathtub, the lake model, uses TN. They increased TKN
from P8 by 11% to get TN for Bathtub. The monitoring data indicates
that TKN should be raised by 20-40% to estimate TN.
3. Their model endpoint was the chlorophyll standard of 40 ug/l, but the
model reports a growing season average. Normally, we apply the chl
standard as an instantaneous one. Michelle suggested using the 25 ug/l
endpoint that was used in the Lake Wylie modeling, 10 years ago.
We had a good conversation where both sides tried to understand the
others' perspective. I'm not sure that's the regulators role, but I've learned
that it works better through good and bad examples at EPA IV;)
Here is the upshot from the 3 concerns:
1. Since Bathtub only uses an annual load, the hydrologic calibration of
P8 isn't too important. We agreed that if they were close on the annual
load, that should do the job.
2. Beth acknowledged that she misread the USGS monitoring report and
that the conversion from TKN to TN should be higher. But she pretty
much used the conversion factor as a calibration parameter to match
the predicted load to the observed load. The predicted load ended up
a little lower than the observed load, so I said that she should at least
match
it. She said that the cove is P limited anyway, but that she'd do a model
run or two with higher N loading.
1 of 2 7/19/02 1:50 PM

spec limits
. that if we go for the
3. ,1,_ founds like a bit of sticking p
oint. Beth said
en the shouldn't use the putted limits
lower target (25 ug/1), y
r ument is that since the model uses annualaverages
the model. Their a g at that level
(one set of values), the plant would never discharge she'll send a report
otherwise, they'd violate their permit. S 1 values for pu
that documents how one ctted limits.
an select model limits in modeling, but that
I told her that normally we use perm le that puts the issue into
we'd think about it. She gave an examons run, the model reports
their perspective. in an existing conditions
loading, while the
lake observed
a chlorophyll value of 19 with observedey use the permitted limits,
Bathtub reports a lake chlorophyll
Toro chlorophyll was 16. If they hyll conc. of 29. I need to look for
this in the report, its ' something to think about. We need to decide
what they should model for plant loading target.
to meet the 25 ug/1
at did the Lake Wylie report (I can't find that) say
about where
Also, wh the 25 ug/l applies - is it a lakewide average or would it apply to a cove?
for an endpoint in Jordan Lake for the New Hope
arm or Robeson cove? *INPUT ��
What are we doing � *vPLEASE*
I told them that we'd try
to have some answers for them in about one
month. I'll be on vacation from 7/23 until8/6.
There's an update for You. Feel free to add anything if you notice
something that's off. Chris
7/19/02 1:50 PM
7 of 2

spec r7%(e14
a
BLACK & VEATCH
8520 Clio Cameron Drive
Suite 350
Charlotte, North Carolina 28269
Tel: [phone]
Fax: (704) 548-WO
Charlotte -Mecklenburg Utilities
McDowell Creek Wastewater Treatment Plant
Water Quality Modeling Report
Ms. Michelle Woolfolk
Division of Water Quality
NC Department of Environment and
Natural Resources
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Dear Ms. Woolfolk:
Black S Veatch International Company
B&V Project 97057.200
B&V File F
February 20, 2002
FEB 21 Z002 U
DEryR -WATER DUALITY
Subject: Water Quality Modeling Final Report
McDowell Creek WWTP
Mecklenburg County
NPDES Permit NC0036277
On behalf of the Charlotte -Mecklenburg Utility Department, we are transmitting 2 copies
of the Water Quality Modeling Final Report for the McDowell Creek Basin for your
review. As we have been discussing, this final modeling report has been prepared for
your use in assessing speculative limits for the proposed expansion to the McDowell
Creek Wastewater Treatment Plant. Refer to the request for speculative limits letter sent
to Mr. David Goodrich on June 5, 2000.
Our Water Quality Modeling Report for the McDowell Creek Basin was originally
submitted to you for review on May 9, 2001. The final report incorporates comments you
provided in a letter dated July 3, 2001, and additional items you requested in an e-mail
dated December 3, 2001.
Please contact me if you have any questions or need additional information to complete
your review. I can be reached at 704-510-8438, or by e-mail at ParkerDM(n,bv.com.
Thank you for working with us on this project.
the imagine • build company"

Ms. Michelle Woolfolk B&V Project 97057.200
NCDENR February 20, 2002
Very truly yours,
BLACK & VEATCH
IN RNATIONAL COMPANY
David M. Parker, P.E.
mpb
Enclosure
cc: David Goodrich, Department of Environment and Natural Resources
Pete Goins, Charlotte -Mecklenburg Utilities (w/enclosure)
Barry M. Gullet, Charlotte -Mecklenburg Utilities (w/enclosure)
Tom Howard, Charlotte -Mecklenburg Utilities (w/enclosure)
Mary Bonislawsky, Black & Veatch (w/enclosure)
Beth Quinlan, Black & Veatch (w/enclosure)
Brent Reuss, Black & Veatch (w/enclosure)

A 9 a FAS IM / 1 /F/K.� ✓i'MGvJ f-
,OF V`1 TF/(� ` S �• �C� Michael F. Easley
1 �(�-y P�tS Governor
/(1C" � William G. Ross Jr.
> ye Y�`' Department of Environment and Natural Resources
/' Kerr T. Stevens
FYI , FJ&5e- 4/) C/Z�/�lj/ `C� . Division of Water Quality
f l
July 3, 2001
Mr. David M. Parker, P.E. Project Manager
Black & Veatch
8604 Cliff Cameron Drive, Suite 164
Charlotte, North Carolina 28269
Dear Mr. Parker,
The North Carolina Division of Water Quality Modeling/TMDL Unit received and reviewed your May
2001 report entitled "Water Quality Modeling Report, McDowell Creek Basin, Mecklenburg County".
The water quality modeling was performed to support the development of speculative limits for the
proposed expansion to the McDowell Creek Wastewater Treatment Plant in Charlotte, North Carolina.
The report describes a two-phase modeling approach, including watershed modeling using P8 and
nutrient response modeling for the McDowell Creek Cove of Mountain Island Lake using BATHTUB.
In order to use the modeling report as a basis for speculative limits, there is some additional
information needed within the context of the modeling report. Specific comments and needs are
described below:
Nonpoint Source Modeling.
♦ Provide additional rationale for maintaining the same set of SCS Curve Numbers for the current
and future land use conditions. It is likely that wooded and agricultural/row crop areas would be
converted to lawns, parks, or newly graded construction sites. This could have a profound effect
on the curve numbers and predictions of water runoff and associated pollutants.
♦ Show, graphically, time series plots of actual versus Dredicted flows, pollutant concentrations, and
pollutant loading rates. While some statistics were presented to describe the model fit, side -by -side
comparisons of daily flows and monthly pollutant loads should be provided to support the assertion
that the model is calibrated to the McDowell Creek watershed.
♦ Describe the statistical relationships that USGS developed for phosphorus and nitrogen loading
within an appendix.
♦ Provide documentation for the nutrient removal rates used in the modeline and describe the
application of the removal. Was the 50% removal applied to both the overland flow and
infiltration? This section should also include descriptions of the SWIM mandates, including buffer
widths.
,04
NNCDE N
Customer Service Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699.1617 [phone]
1-877-623-6748
http://www.enr.state.ne.us

Page 2 of 2
Lake Modeling.
♦ Show, graphically, time series plots of actual versus predicted pollutant concentrations for the
various submodels. (Similar to comment for nonpoint source modeling.) This should include the
nutrient sedimentation submodel.
♦ Provide additional information to support the statement that water quality improved after TP
reductions at the McDowell Creek WWTP. This should include both in -lake data as well as
loading rates from the WWTP.
♦ Use actual loading for the 1998 and 1999 model calibration and existing conditions. Current
permit limits were used to represent loads for phosphorus, nitrogen, and ammonia.
Should DWQ accept this model as the basis for speculative limits for a discharge to an impaired
waterbody, we would need electronic copies of both the raw input and output files to the P8 and
BATHTUB models. Thank you for providing DWQ with the opportunity to review this model. If you
have any questions about our comments, please contact Betsy Albright at [phone] ext. 514 or
me at [phone] ext. 505.
Sincerely, / _. /�
qw�(loI61r°411�
Michelle Woolfolk, Supervisor
Modeling/TMDL Unit
cc: Betsy Albright, DWQ Modeling/TMDL Unit
Dave Goodrich, DWQ NPDES Unit
Boyd Devane, DWQ Planning Branch
ANCl7ENR
Customer Service
1-877-623.6748
Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 [phone]

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NC0036277- CMUD McDowell Creek
Spec Limit Request -proposing expansion from 6.0 MGD to 7.8, 9,12, and 18 MGD
Prepared By: Tom Belnick, NPDES Unit
Date: 6/27/00
Flow, MGD
BOD(S), mg/l
BOD(W), mg/l
NH3(S), mg/I
NH3(W), mg/l
TSS, mg/l
DO, mg/I
Fecal, org/100ml
TN,mg/I
TP,mg/I
ChronicTox @
TN,lb/year
TP,lb/year
Monthlv Averaae Effluent Limits
6
7.8
9
12
18
5
3.84
3.33
2.5
1.67
10
7.69
6.67
5
3.33
2
1.54
1.33
1
0.67
2.5
1.92
1.67
1.25
0.83
&1�200
30
30
30
30 II
200
200
2
10
7.69
6.67
5
3.33
1
0.77
0.67
0.5
0.33
85%
88%
89%
92%
94%
182,646 182,646 182,646 182,646 182,646
18,265 18,265 18,265 18,265 18,265
Toy -548- SYb i
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NC0036277- CMUD McDowell Creek
Spec Limit Request -proposing expans' n from 6.0 MGD to 7.8, 9,12, and 18 MGD ���� j v x
Prepared By: Tom Belnick, NPDES nit
Date: 6/27/00
Monthlv Ave oe Effluent Cubits
Flow, MGD
BOD(S), mg/I Q��
BOD(W), mg/I PAll
NH3(S), mg/I p0 l
NH3(W), mg/I podt
TSS, mg/I
DO, mg/I
Fecal, org/100ml
TN,mg/I
TP,mg/I
ChronicTox @
5/ 5- 5
10 10 10
2 1 1
2.5 2 2
30 30 30
>5 >5 >5
200 200 200
10 7.69 6.67
1 0.77 0.67
85% 88% 89%
TN,lb/year - Ob ff'Id 182,646
TP,lb/year SD Jy-/.y 18,265
5 5
10 10
1 1
30
30
>5
>5
200
200
5
3.33
92%
940Y.
182,646 182,646 182,646 182,646
18,265 18,265 18,265 18,265
CAW
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BLACK & VEATCH
8604 Cliff Cameron Drive, Suite 164
Charlotte, North Carolina 28269 USA
Tel:[phone]
Fax: [phone]
Charlotte -Mecklenburg Utilities
McDowell Creek Basin Flow Study
Mr. David A. Goodrichr
NPDES Supervisor
North Carolina Department of Environment
and Natural Resources
Division of Water Quality
512 North Salisbury Street
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Dear Mr. Goodrich:
Black & Veatch International Company
B&V Project 97057.100
June 5, 2000
JUN
Subject: Speculative Limits Request
McDowell Creek WWTP
NPDES Permit NC0036277
On behalf of Charlotte -Mecklenburg Utilities, we are requesting speculative NPDES limits for
our use in planning for expansion of the McDowell Creek Wastewater Treatment Plant. As we
discussed in our telephone conversation May 2, 2000, we are a conducting comprehensive study
of the McDowell Creek Basin to evaluate the build -out growth in this basin and how best to
protect our downstream water supply. At the same time, there is an immediate need to provide
additional capacity due to an increase in wastewater flow that has greatly exceeded our
projections.
The McDowell Basin Study will evaluate the ultimate capacity requirements of this regional
plant, the rate of development and corresponding rate of increase in flows to the plant, and
determine both short-term and long-term alternatives to meet the requirements. The alternatives
will include water conservation, water reuse, spray irrigation, conveyance to other basins, and
expansion of the existing plant using advanced tertiary treatment methods.
We request that the speculative limits be based on state water quality guidelines. We
acknowledge there are local ordinances that may be more stringent than the water qul
limits. We also acknowledge that it is our responsibility to comply with these
the imagine -build company-

Mr. David A. Goodrich
Page 2
June 5, 2000
We are considering a phased expansion of the McDowell Creek WWTP from its current capacity
of 6.0 mgd to 7.8 mgd, 9.0 mgd, 12.0 mgd, and 18.0 mgd. Please provide us with speculative
limits for each of these flows.
If it will be helpful to you and your staff, we are available to meet at your convenience to discuss
this further. Time is of the essence and we request a priority be placed on our request.
Please contact me if you have any questions.
Yours very truly,
BLACK & VEATCH
INTERNATIONAL COMPANY
Brent M. Reuss
Project Manager
McD2/jhb
cc: Pete Goins, CMU
Barry Gullet, CMU
Jerome Lucky, CMU
Jim Hawkins, B&V
Dave Parker, B&V

h
n
6
L
a 3

DIVISION OF WATER QUALITY
MEMORANDUM
TO: Interested Parties
FROM: Coleen Sullins, Division of Water Quality, Section Chief
DATE: June 2, 2000
RE: Minimum Thresholds for Wastewater Treatment Plant (WWTP) Expansions Under the
North Carolina Environmental Policy Act (SEPA)
It has come to my attention that clarification is needed concerning application of DENR's SEPA
Minimum Criteria for WWTPs that are expanding (15A NCAC I .0504(3)). The current confusion
in applying these rules appears to stem from rule revisions that occurred in 1996. Prior to 1996, the
rules treated both new and expanding facilities as one category, exempting projects from SEPA
review if either a proposed new facility or an expansion to an existing facility would result in an
additional discharge of less than 500,000 gallons per day (GPD) or produce an instream waste
concentration of less than 33 percent during the 7-day 10-year low flow conditions (7Q 10). In 1996,
the revised rules separated the criteria for new and expanding facilities, retaining the same criteria as
listed above for new discharge facilities but only listing the 500,000 gallons per day criteria for
expanding facilities. Therefore, when a WWTP is expanding_and is subject to SEPA because there
are public funds and a state action i ,.a.SEPAZocument will..be=quir,_ ed only if the eMans on
is greater an GPD. However, the Secretary of DENR has the authority to require an
environmental document under SEPA for any project which has the potential to cause major
environmental impacts, even if the project falls below DENR's Minimum Criteria (i.e., is considered
a non-major.activity). For example, in the case of a WWTP expansion if the potential impacts of a
proposed expansion would include the loss of an existing water use, an environmental review could
be required, even if the expansion would result in an additional discharge of less than 500,000 GPD.
Note that the Minimum Criteria are currently being reviewed by the Department for changes and
therefore the SEPA thresholds for new and expanding facilities may be amended, by rule, in the near
future.
Please contact Steve Zoufaly of my staff at 919-733-5083, ext. 566 if there are questions regarding
the SEPA requirements.
Cc: Tommy Stevens
Regional DWQ Supervisors
Dave Goodrich, NPDES Unit
Bobby Blowe, Construction Grants and Loans

1
.___.. ....._ __ 16 .�
[Fwd: [Fwd: EA requir mere and 7Q10s]]
SubjecX[F di [Fwd: EA requirements and 7Q10s]]
DatT�e, 8Apr 2000 15:06:48 -0400
From: ave Goodrich <[e-mail]>
To: Susan A Wilson <[e-mail]>,
Boyd Devane <[e-mail]>, Alan Clark <[e-mail]>,
Steve Zoufaly <[e-mail]>, Gloria Putnam <[e-mail]>
So, it was Dennis and Boyd, eh?
Well, I'm just not sure what to do. Conceptually, I really don't have a
problem with Boyd's interpretation. I don't think that we're putting
water quality'at great risk by using his translation of the rules. I
just want to make sure that we're being consistent. I will tell you
that I recall doing this for Randleman (this is where my institutional
memory starts on this issue) and CMUD-McDowell Creek WWTP (Greg N.
caught it during a meeting after Coleen and I missed it). There may be
more examples, but.that's all I can remember off the top of my head.
(It really doesn't come up that often.) I think what would be nice to
see is a written policy memo. for Coleen's or Tommy's or Greg's
signature clarifying all of this. That way we can all be sure we're
giving the same answers.
Subject: Re: [Fwd: EA requirements and 7Q10s]
Date: Tue, 18 Apr 2000 12:33:36 -0400
From: Boyd Devane <[e-mail]>
To: Alan Clark <[e-mail]>
CC: Gloria Putnam <[e-mail]>, Steve Zoufaly <[e-mail]>,
Dave Goodrich <[e-mail]>
The beauty of the departments SEPA rules for minor activities is that they were so poorly written
(Dennis and I did most of it.) that they allow great flexibility. As for the expansions, I'm pretty sure we
intended that any expansion of less than 500,000 gpd would be "non -major". We say it it .0504(3)(a)(iii)
"expansions of existing facilities ... of less than 500,000 gpd" are minor. At the time of the writing of
these rules, we did not have the enlightened definition of "new" that Dave referenced where "new" also
included "old". (I thought there was a much better way to write that definition in the point source rules
but I lost that argument with Don.) When we wrote the minimum critieria, we just thought that "new"
meant new and expansion meant expansion. Therefore Dave, although it seems like a legitimate thing to
do to use the 2H 100 definitions, I don't think it is appropriate in this case because of the chronological
factor.. Also in the minimum criteria in 1 C .0504(4)(t), we had the condition that "modifications in previoussly permitted discharges resulting in an increased flow of less than 500,000 gallons per day" are
to be considered minimum. Whether that's a good rule or not, it's there. Of course, we can call for an EA
any time we desire and don't hesitate to do that.. Our intent of having (a)(ii) was that any discharge
under 500,000 that went into a small stream should have an EA done regardless. I'd say it was an
oversite that we didn't make it clear what to do with existing discharges expanding to over 1/3 of the
stream flow and from the other wording in the rules, I'd have to go in favor of no mandated EA for Troy.
Alan Clark wrote:
To my knowledge, the interpretation Dave is applying to expanding discharges must
have occurred after the SEPA position left my unit and was reassigned under Lisa
Martin or eventually under Steve when we had several temps. During the time I was
involved with SEPA as the coordinator and supervisor, the only expanding discharges
requiring SEPA review that I remember (and my memory isn't what it used to be) were
those that expanded by greater than 500,000 gallons per day. You might see if he
has some examples to prove his point.
1 of 3 11/28/00 1:00 PM

[Fwd: [Fwd: EA requirements and 7Q10s]]
Gloria Putnam wrote:
> Alan,
> Would you please read Dave's e-mail below and see if this "jogs" any
> previous discussions on the subject. This is in relation to what we
> discussed yesterday of when the DENR SEPA minimum criteria applies to
> WWTP expansions.
> I'm not questioning his institutional memory - I'm just trying to get a
> broader perspective - if there is one.
> Thanks, Gloria
> ------------------------------------------------------------------------
0
> Subject: Re: EA requirements and 7Q10s
> Date: Tue, 18 Apr 2000 09:08:06 -0400
> From: Dave Goodrich <[e-mail]>
> To: Gloria Putnam <[e-mail]>
> CC: Susan Wilson <susan.a [e-mail]>,
> Steve Zoufaly <[e-mail]>
> References: <[e-mail]> <38FB5988.1C4D2D8C@ncma]l.net>
> Gloria,
> This is not how we've interpreted the minimum criteria historically. One of the
> problems with the current SEPA rules is that terms are not always defined.
> Therefore, several years back we discussed what was meant by "new" flow at an
> NPDES facility. Since there wasn't a definition in the SEPA rules, we went to
> the 2H .0100's (which had specifically been changed to clarify the distinction
> between existing and new/expanding facilities). This definition includes
> "expanding facilities" within its definition of new. Also, we've taken the
> environmentally -conservative line of thinking that expansions that equate to IWC
> >33% (total flow) will require SEPA documentation even if the discharge
> currently comprises an IWC of greater than 33%. This may be something we need
> to consider for changes in the minimum criteria definitions, but for now that's
> my understanding of how we've done things in the past.
> - Dave
> Gloria Putnam wrote:
> > Susan,
> > I still don't believe that an EA should be required for Troy and provide
> > some thoughts on it below. However, I am open to your arguments of why
> > specifically SEPA should apply. Also, even if we were to agree that the
> > criteria do not apply, we have the discretion to call for an EA if we feel
> > it is warranted. If either you or Dave feel the Troy project has the
> > potential to have a significant adverse environmental impact, we can work to
> > get the approval of the Director and the Secretary to require an EA for the
> > project.
> > As I understand it (from the draft EA guidelines that Michelle Suverkruebbe
> > put together) it has been interpreted that expansions would only apply to
> > the criteria for "new wastewater spray irrigation, rotary distribution, or
> > subsurface wastewater systems." These particular systems are not
> > specifically discussed in terms of "new" and "expanding", as is done for
> > W WTPs. Therefore, I believe that the 500,000 gpd criteria is the only one
> > that we should use for expanding systems.
of 3

If we were to apply the criteria for "new discharge facilities" to
"expanding facilities," it seems as though an EA would only be triggered if
> > the expansion would cause the discharge to "exceed 1/3 of the 7Q10 of the
> > receiving stream." If a discharge already exceeds 33 % of the 7Q 10, then the
> > only trigger that I can see would be the 500,000 gpd expansion. In the case
> > of Troy, I believe their WWTP instream waste concentration is already over
> > 90% of the receiving stream (Susam correct me if I'm wrong on this). And
> > their requested expansion is only 360,000 gpd.
> > Those are my thoughts ...
> > As Dave is aware, our SEPA minimum criteria are being re-evaluated. This
> > looks like an issue we should address in the new rules. Please provide me
> > with any suggestions you have on how to improve/clarify them ...
> > Thanks.
> > Gloria
> > Susan Wilson wrote:
> > > Gloria, i'll have to say a big "oops" on this one. i think i didn't
> > > have an opportunity to speak with Dave about this (and i thought it was
> > > obvious from the '96 language), but i brought this up in our staff
> > > meeting this morning. i think you and i had read the rule for minumum
> > > criteria as not having to perform an EA for facilities making up > 1 /3
> > > 7Q 1 Os/IWC if the facility was expanding. however, Dave clarified this
> > > as that we have interpreted "new" as defined in the 2H .0100 rules [2H
> > > .0103(14)]. he said they have this discussion a few years back (w/Alan)
> > > and made the determination that EA requirements would be interpreted
> > > this way for new or expanding facilities.
> > > OK, who wants to call troy? i had actually forgotten to call gray
> > > before i had to take off all. last week - but I'm sure his consultant has
> > > relayed your news.
> > > sorry for the confusion - i was not aware.
3 of 3 11/28/00 1:00 P1

Percent of Industrial Flow to Total Facility Flow
NPDES # of all POTW
Treatment Plants Receiving
Industrial Wastewater
Irwin Creek - NC0034945
Mallard Creek - NC0030210
McAlpine Creek - NC0024970
McDowell Creek - NC0036277
Sugar Creek - NC0024937
NPDES # of Major POTWs
Irwin Creek - NC0034945
Mallard Creek - NC0030210
McAlpine Creek - NC0024970
McDowell Creek - NC0036277
Sugar Creek - NC0024937
Total
Total Design Flow Total Actual Flow Industrial Flow
(Daily Average-MGD) (Daily Average-MGD) Recived
FY 2000 FY 2000 % of Actual
FY 2000
15 10.184 11.83%
8 5.587 0.20%
48 40.132 5.37%
6 3 _6: g 0.020%
20 15.253 5.78%
Industrial Users per Facility
Number of Categorical Number of Significant Total
Industrial Users (CIU's) Non -Categorical
Industrial Users
10 19 29
2 2
10 30 40
4' M41111
11 14 25
34 63 97

6
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.).

0 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
per sludge 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. Supemate 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
BOD
x
x
x
x
x
COD
X
X
X
X
X
TSS
x
x
x
x
x
O&G
X
X
X
X
NH3-N
x
x
x
x
x
Total
Nitrogen
x
x
x
x
x
x
x
Total
Phosphorus
x
x
x
x
x
x
x
As *
x
x
x
x
x
x
x
x
Cd
x
x
x
x
x
x
x
x
Cr
x
x
x
x
x
x
x
x
Cu
x
x
x
x
x
x
x
x
Pb
x
x
x
x
x
x
x
x
Hg*
x
x
x
x
x
x
x
x
Mo*
x
x
x
x
x
x
x
x
Ni
x
x
x
x
x
x
x
x
Se
x
x
x
x
x
x
x
x
Ag
x
x
x
x
x
x
x
x
Zn
x
x
x
x
x
x
x
x
CN
x
x
x
x
% solids
x
Flow
x
x

H. Detection level and Sample Method
P. O. C.
Detection Level (mg/1)
Sample 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.