NC0003042_More Information (Requested)_20170714

Water Resources
Environmental Quality
July 14, 2017
CERTIFIED MAIL 7002 0860 0006 58361110
RETURN RECEIPT REQUESTED
Mr Thomas S. Warren, Jr
City of Roxboro
P.O. Box 128
Roxboro, NC 27573
Dear Mr. Warren:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. JAY ZIMMERMAN
Director
Subject: Request for Additional Information
Renewal Application
Roxboro WTP
NPDES permit NC0003042
Person County
The Division has reviewed your application, received on October 3, 2016, for renewal of NPDES permit
NC0003042 To enable us complete our review in accordance with N.C.G.S. 143-215.1 and 15A NCAC
2H.0105, please provide additional or revised information to address the following comments:
1. Please provide five (5) days of Total Hardness (CaCO3 or (Ca + Mg)) data for the effluent at
Outfall 001.
2. If flow is present In the receiving stream, please provide five (5) days of Total Hardness (CaCO3 or
(Ca + Mg)) data upstream from Outfall 001
Review of our records indicates that there is no stream flow data documented for the receiving
stream. Please provide a 7Q10 and 30Q2 at the location of Outfall 001 [36.411944°, -79.001111°],
for the unnamed tributary to UT to Marlowe Creek from the following contact with the US
Geological Survey:
J. Curtis Weaver, Hydrologist, PE
USGS North Carolina Water Science Center
3916 Sunset Ridge Road
Raleigh, NC 27607
Phone- [phone] // Fax. [phone]
E-mail address -- jcweaver@usgs gov
Internet address -- httn://nc.water.us sg aov/
The NC 2007-2014 Water Quality Standard (WQS) Tnenmal Review was approved by the NC
Environmental Management Committee (EMC) on November 13, 2014. The US EPA subsequently
approved the WQS revisions on April 6, 2016 with some exceptions. The NC Division of Water
Resources is required to implement the new dissolved metal standards in all permits public noticed after
April 6, 2016.
The new standards for most metals include acute standards Furthermore, the freshwater standards for
several metals are expressed as the dissolved form of the metals, and seven metals have hardness -
dependent equations. As a result, the Division will need site-specific effluent hardness data and instream
State of North Carolina I Environmental Quality
1617 Mail Service Center I Raleigh, North Carolina 27699-1617
919-707-9000

Mr. Warren
July 14, 2017
Page 2 of 2
hardness data, upstream of the discharge, for each facility monitoring these metals in order to calculate
permit limitations. The metal of concern for this permit renewal is Copper.
To evaluate dissolved Copper, a Reasonable Potential Analysis (RPA) was conducted using data from
DMRs (Feb2015 May2017). Please see the attached RPA spreadsheets for Outfall 001. Results indicated
a reasonable potential to exceed the new dissolved metal standard for Copper. Consequently, the
following daily maximum limits (acute standard) and monthly average limits (chronic standard) for Total
Copper could be applied for this permit renewal:
Parameter Outfall Monthly Average Limit Daily Maximum Limit
Copper 001 7.88 gg/L 10.47 µg/L
To calculate these limits a default hardness of 25 mg/L was entered for both the effluent and upstream
values. Additionally, a 7Q 10 of zero was used for this calculation. For a summary of this information,
please see the attached "Dissolved to Total Metal Calculator". Incidentally, the additional information
requested will be used in a recalculation for the draft permit.
If no response is received within 60 calendar days [per 15A NCAC 211.0107(b)], the permit will be
renewed without the benefit of the requested additional information. Therefore, a default hardness of 25
mg/L and a 7Q 10 of zero will be used to calculate effluent limits for Copper as indicated.
If you have any questions, please contact Derek Denard at 919-807-6307 or email at
derek. denard@ncdenr. gov.
Sincerely,
Derek Denard, Environmental Specialist
Compliance & Expedited Permitting Unit
Division of Water Resources, NCDEQ
he NPDES Permit Files
Central Files
RRO Files
ec Danny Smith [danny smith@ncdenr gov]
Thomas S Warren, Jr [twarren@cityofroxboro com]

Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
REQUIRED DATA ENTRY CHECK WOS
T-, L.I., � �...:....a I..i..�.....,�:....
❑CHECK IF HQW OR ORW WQS
Facility Name
City of Roxboro - Roxboro WTP
ParO
WWTP/WTP Class
PC -1
ParO
NPDES Permit
NC0003042
ParO
Outfall
001
ParO
Flow, Qw (MGD)
2.325
ParO
Receiving Stream
UT to Marlowe Creek t
ParO
HUC Number
030101040602
Paro
Stream Class
1 Copper
ParO
❑Apply WS Hardness WQC
C
ParO
7Q10s (cfs)
0.00
Part
7Q10w (cfs)
0.00
Part
30Q2 (cfs)
0.00
Part
QA (cfs)
0.00
Part
1Q10s (cfs).00
0
Part
Effluent Hardness
25 mg/L (Avg)
Part
Upstream Hardness-
_ _ _ _ _
25 mg/L (Avg) I
-----
Part
Combined Hardness Chronic
__ _ _ _ _ _ _
25 mg/L-
Part
Combined Hardness Acute
_ _ _ _ _ _ _ _I
25 mg/L I
Part
Data Source(s)
BIMS DMRs DeC2012 to May2017-, flow June2014 to
Part
❑CHECK TO APPLY MODEL
May 2017
Part
Part
Par2
Par2
,_ ...... ..-.,..,_. ..:.. .- -... ,.,-. _-.. ,-
Par2
Follow directions for data entry. In some cases a
Par2
comment menu list the available choices or a
dropdown menu will provide a list you may select
from. Error message occur if data entry does not
meet input criteria.
Table 2. Parameters of Concern
Name
was Type Chronic Modifier Acute PQL Units
1
2
3
4
5
s
7
a
9
0
1 Copper
Aquatic Life NC 7.8806 FW 10.4720 ug/L
2
3 Fluoride
Aquatic Life NC 1,800 FW ug/L
4
5
6
7
s
s
0
1
2
3
4
5
NC0003042 RPA 2017, input
7/13/2017

REASONABLE POTENTIAL ANALYSIS
H1
H2
"PASTE SPEC
Use "PASTE SPECIAL
Effluent Hardness
I.lues" then "COP
Upstream Hardness
Values' then "COPY"
Maximum data
. Maximum data
points = 58
points = 58
Date Data BDL=1/2DL Results
Date Data BDL=1/2DL Results
1
25 25 Std Dev.
N/A
1
25 25 Std Dev.
N/A
2
Mean
25.0000
2
Mean
25.0000
3
C.V.
0.0000
3
C.V.
0.0000
4
n
1
4
n
1
5
10th Per value
25.00 mg/L
5
10th Per value
25.00 mg/L
6
Average Value
25.00 mg/L
6
Average Value
25.00 mg/L
7
Max. Value
25.00 mg/L
7
Max. Value
25.00 mg/L
8
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
NC0003042 RPA 2017, data
1 7/13/2017

REASONABLE POTENTIAL ANALYSIS
Pall
Par13
Use "PASTE SPEC
Use "PASTE SPECIAL
Copper
Values" then "COP
Fluoride
Values" then "COPY"
. Maximum data -
. Maximum data
points = 58
points = 58
Date Data
BDL=112DL
Results
Date
Data
BDL=112DL
Results
1
2/3/2015
4
4
Std Dev.
7.6239
1
4/7/2015
<
500
250
Std Dev.
39.7213
2
4/7/2015 <
5
2.5
Mean
9.2500
2
7/16/2015
240
240
Mean
235.5556
3
5/12/2015
6
6
C.V.
0.8242
3
10/20/2015
<
500
250
C.V. (default)
0.6000
4
6/2/2015
7
7
n
26
4
1/21/2016
<
500
250
n
9
5
7/16/2015 <
5
2.5
5
4/28/2016
<
500
250
6
8/11/2015
34
34
Mult Factor =
1.35
6
7/14/2016
130
130
Mult Factor =
1.81
7
9/1/2015
19
19
Max. Value
34.00 ug/L
7
10/20/2016
<
500
250
Max. Value
250.0 ug/L
8
9/15/2015
3.1
3.1
Max. Pred Cw
45.90 ug/L
8
1/26/2017
<
500
250
Max. Pred Cw
452.5 ug/L
9
10/20/2015
7.4
7.4
9
4/4/2017
<
500
250
10
11/17/2015
7
7
10
11
12/8/2015
5
5
11
12
1/21/2016
5.5
5.5
12
13
2/9/2016
5
5
13
14
3/30/2016
7
7
14
15
4/28/2016
7.8
7.8
15
16
5/10/2016
7
7
16
17
7/14/2016
22
22
17
18
8/9/2016
26
26
18
19
9/16/2016
11
11
19
20
10/20/2016
8.6
8.6
20
21
11/18/2016
9
9
21
22
12/19/2016
8
8
22
23
1/26/2017 <
5
2.5
23
24
2/6/2017
8
8
24
25
4/4/2017
6.6
6.6
25
26
5/8/2017
9
9
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
NC0003042 RPA 2017, data
- 2 - 7/13/2017

City of Roxboro - Roxboro WTP
NC0003042 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 2.32470968 MGD
COMBINED HARDNESS (me/I.)
Acute = 25 mg/L
Chronic = 25 mg/L
PARAMETER
MAXIMUM DATA POINTS = 58
Qw (MGD) = 2.32
WWTP/WTP Class: PC -1
1Q10S (cfs)= 0.00
lWC% @ IQ10S = 100
7Q10S (cfs) = 0.00
IWC% @ 7Q10S = 100
7Q10W (cfs) = 0.00
IWC%@ 7Q10W = 100
30Q2 (cfs) = 0.00
IWC% @ 30Q2 = 100
Avg. Stream Flow, QA (cfs) = 0.00
IW%C @ QA = 100
Receiving Stream: UT to Marlowe
Creek HUC 030101040602 Stream Class: C
Outfall 001
Qw = 2.32470968 MGD
COMBINED HARDNESS (me/I.)
Acute = 25 mg/L
Chronic = 25 mg/L
PARAMETER
NC STANDARDS OR EPA CRITERIA
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
TYPE
11)
a
a
r-
Chronic Applied \Cutc
tl :1)ct- 11trsPred(\t Allowable Cw
Standard
Acute: 10.47
Copper
NC
7.8806 FW 10.4720
us_
I
2G 23
45.90
RP shown - apply Monthly Monitoring with Limit
_ ___ _ __
ChiO111C 7.88
_ _ _ _ _ _ _ _ _ _ _ ___
RP shown - apply Monthly Monitoring with Limit
10 values > Allowable Cw
Acute: NO WQS
Fluoride
NC
1800 F\V
ug/L
9 2 452.5
Note: n <_ 9 Default C.V.
_
Chronic 1,800.0
Limited Dataset (n<8 samples) - apply Quarterly
Limited data set
No value > Allowable Cw
Monitoring
NC0003042 RPA 2017 rpa
Page 1 of 1 7!13/2017

Date: 7/13/2017
FACILITY: City of Roxboro - Roxboro WTP
NPDES PERMIT: NC0003042
Dissolved to Total Metal Calculator
in accordance with Federal Regulations, permit limitations
must be written
as Total Metals per 40 CFR 122.45(c)
Receiving Receiving
Rec. Stream
DES
NPTotal Suspended
Combined Combined
Instream Instream Effluent
Stream Stream
-Fixed Value-
Solids
Hardness
Concentration Concentration
Upstream
7O10(CFS)
(MGD)
MGD MGD
(mg/L)
(mg/L) (mg/L)
Average (mg/L)
(Chronic) (Acute)
(mg/L)
o.0000
0 ooao
0 000o z 3zn� to
zs o0o z5 00o
too.0000 t00.0o00 25
25
Upstream Hard Avg (mg/L) = 25
EFF Hard Avg (mg/L) = 25
US EPA Maximum Allowable Effluent Concentration
COMMENTS (identify parameters to PERCS Branch to maintain in facility's LTMP/STMP):
Dissolved Metals
Translators- using
(MAEC) as a Total Metal
PARAMETER
Default Partition
=Dissolved Metal -Translator
ChonicrAcute
Coefficients
Chronic Acute
u /l u /I
streams
u l u i
Cadmium (d) 0.15 0.82
0.252
0.59 3.24
Cd -Trout strea 0.15 „ 0.51
0.252
0.59 2.01
Chromium III (d)(h) 24 183
0.202
117.73 905.0
Chromium VI d 11 16
1.000
11.00 16.0
Chromium, Total t
N/A N/A
Copper (d)(h) 2.7 3.6
0.348
7.86 10.47
Lead (d)(h) 0.54 14
0.1
2.94 75.4
Nickel (d)(h) 16 145
0._432
37.23 335.21
1-1- WS streams (t)
Silver (d)(h,acute) 0.06 0.30
1.000
0.06 0.30
anc (d)(h) 36 36
0.288
126.73 125.71
Be Ilium
000
Arsenic (d)
1.000
340
(d) = dissolved metal standard. See 15A NCAC 02B.0211 for more information.
(h) = hardness -dependent dissolved metal standard. See 15A NCAC 02B.0211 for more information.
(t) = based upon measurement of total recoveable metal.
See 15A NCAC 02B.0211
for more information.
The Human Health standard for Nickel in Water Supply Streams is 25 mg/L which is Total Recoverable metal standard.
The Human Health standard for Arsenic is 10 µg/L which is Total Recoverable metal standard.
Hardness Hardness
Wastewater Wastewater
Hardness
summer
summer 7010
1010 Flow Limit
-Fixed Value-
Chronic Acute
Hardness
Concentration Concentration
Average
7O10(CFS)
(MGD)
MGD MGD
(mg/L)
(mg/L) (mg/L)
Average (mg/L)
(Chronic) (Acute)
(mg/L)
o.0000
0 ooao
0 000o z 3zn� to
zs o0o z5 00o
too.0000 t00.0o00 25
25