NC0026611_Speculative Limits_19961127

NPDES DOCUHENT SCANNING COVER :SHEET
NC0026611
Morehead City WWTP
NPDES Permit:
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Meeting Notes
Instream Assessment (67b)
(Speculative
nY:
Limits
_._"mow:,.,,.
Environmental Assessment (EA)
Document Date:
November 27, 1996
This document is printed on reuse paper, - igznore any
content on the reYerse side

State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
Joe Claytor, Director
Water and Sewer Department
P.O. Drawer M
Morehead City, NC 28557
Dear Mr. ayton:
request for speculative limits, submitted by Mr. Tyndall Lewis with McDavid
Associates, Inc., has been reviewed by the Instream Assessment Unit. Due to persistent.
water quality problems in Calico Creek over the past decade the Division of Water Quality
will not permit an expansion of the Morehead City WWTP at this time.
During the summer months dissolved oxygen (DO) concentrations in Calico
Creek routinely drop well below the water quality standard of 5.0 mg/L. Over the past two
years DO levels as low as 0.9 mg/L have been reported by the Town. Diurnal fluctuations
in DO indicate that eutrophication may also be a problem in Calico Creek. Chlorophyll -a
measurements collected in 1995 yielded numerous violations of the state standard, with
chlorophyll -a concentrations reported as high as 234 ug/L.
The Division recognizes and supports the individual efforts made by the Carteret
County Interlocal Agency, and the joint efforts by Carteret, Craven, Onslow, and Pamlico
Counties to pursue regionalized long-term wastewater management solutions. Additional
waste flow into Calico Creek may be considered justifiable as an interim component of a
regional management plan that ultimately eliminates the discharge or results in achievement
of water quality standards.
The Division will be glad to meet with the Town and its consultants to discuss
possible wastewater treatment and disposal options. If you have any questions, please do
not hesitate to contact Andy McDaniel at 733-5083, ext 513.
1: 07?
November 27, 1996
DEC j 1996
WATER QUA,I�
SE+CT1pN
Subject: Request for Speculative limits
Morehead City WWTP
NPDES No. NC0026611
Carteret County
Sincerely,
A. Preston Howard
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10% post -consumer paper

Morehead City WWTP
NC0026611
Qw=1.7 MGD
Calico Creek "SC"
AHM
8/8/97
• Morehead City WWTP has a permit to discharge 1.7 MGD into Calico Creek, a class SC stream that
flows east into the Newport River near the Beaufort Inlet.
• The current permit limits for conventional parameters are as follows:
Monthly Average
Summer Winter
Wasteflow (MGD): 1.7 1.7
BOD5 (mg/I): 20.0 30.0
NH3N (mg/1): monitor monitor
DO (mg/1): 5.0 5.0
TSS (mg/I): 30.0 30.0
Fecal Col. (/100 mi): 86.0 86.0
pH (SU): 6.8-8.5 6.8-8.5
Residual Chlorine (µg/1): monitor monitor
Temperature (C): monitor monitor
TP (mg/1): monitor monitor
TN (mg/I): monitor monitor
Acute Toxicity P/F Qtrly
• Water quality violations of the state standard for dissolved oxygen and chlorophyll -a have been
occurring in Calico Creek for many years (see attached graphs). These problems have been
exacerbated by the fact that Calico Creek is poorly flushing and tidally influenced.
• Nutrients as well as oxygen consuming wastes are believed to be significant contributors to the
impairment of Calico Creek.
• Dye studies indicate that the effluent remains in the vicinity of the discharge for at least one complete
tidal cycle.
• The City is severely limited in choices for alternative sites for a surface water discharge as most of the
major water ways surrounding the city are classified SA. The SA waters at the confluence of Calico
Creek and the Newport River are currently closed to shell fishing.
• A modeling analysis of Calico Creek was completed in 1990. Based on the modeling report removal
of the discharge was recommended in the White Oak Basinwide Plan. The report indicates that if
removal of the discharge is not an option then the facility should be required to meet advanced tertiary
limits including nutrient removal for nitrogen and phosphorus.

Loading Summary for Oxygen Consuming Wastes and Nutrients
Morehead City WWTP/Calico Creek "SC"
BODS
Permitted load = 284 lb/d
Average summer load ('96) = 127 lb/d
Average annual load ('96) = 123 lb/d
Current limit: 20 mg/L (S) / 30 mg/L (W)
Ata5 mg/L
At a 5 mg/L
limit load = 71 lb/d (assuming Qw = 1.7 MGD)
limit load = 104.2 lb/d (assuming Qw = 2.5 MGD)
Ammonia
Permitted load = monitor
Average suimer load = 11.3 lb/d
Average annual load = 10.8 lb/d
No limit in qurrent permit
At a 2 mg/L
At a 1 mg/L
Ata2mg/L
At a 1 mg/L
limit load = 28.3 lb/d (assuming Qw = 1.7 MGD)
limit load = 14.2 Ib/d (assuming Qw = 1.7 MGD)
limit load = 41.7 lb/d (assuming Qw = 2.5 MGD)
limit load = 20.8 lb/d (assuming Qw = 2.5 MGD)
TP
Permitted load = monitor
Average summer load ('96) = 22.0 lb/d
Average annual load ('96) = 16.9 lb/d
At a 2 mg/L
At a 1 mg/L
At a 0.5 m
limit load = 28.4 lb/d (assuming Qw = 1.7 MGD)
limit load = 14.2 lb/d (assuming Qw = 1.7 MGD)
L limit load = 7.1 lb/d (assuming Qw = 1.7 MGD)
At a 2 mg/L limit load = 41.7 Ib/d (assuming Qw = 2.5 MGD)
At a 1 mg/L limit load = 20.8 Ib/d (assuming Qw = 2.5 MGD)
At a 0.5 mg/L limit load = 10.4 lb/d (assuming Qw = 2.5 MGD)
TN
Permitted 10 d = monitor
Average summer load ('96) = 53.8 lb/d
Average an ual load ('96) = 54.8 Ib/d
At a 6 mg/L limit load = 85.0 lb/d (assuming Qw = 1.7 MGD)
At a 4 mg/L limit load = 56.7 lb/d (assuming Qw = 1.7 MGD)
At a 2 mg/L limit load = 28.3 lb/d (assuming Qw = 1.7 MGD)
At a 1 mg/L limit load = 14.2 lb/d (assuming Qw = 1.7 MGD)
At a 6 mg/L limit load = 125.1 lb/d (assuming Qw = 2.5 MGD)
At a 4 mg/L limit load = 83.4 lb/d (assuming Qw = 2.5 MGD)
At a 2 mg/L limit load = 41.7 lb/d (assuming Qw = 2.5 MGD)
At a 1 mg/L limit load = 20.8 lb/d (assuming Qw = 2.5 MGD)
Flow
Permitted flow = 1.7 MGD
Average summer flow ('96) = 1.523 MGD
Average annual flow ('96) = 1.404 MGD

DO Concentration (mg/L)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
1-Jan-95
Morehead City WWTP Qw = 1.7 MGD
Calico Creek "SC"
Instream Dissolved Oxygen Concentration
April 1995 - June 1997
■
■
■
♦
m
s 1I
♦—ig
ii■
e•
♦♦
0 i
,„,
•�°
•
�
•4�
.
IP
Nir
NA
•
Ao
♦
■
III♦ �♦f
11"
1a
aE
♦
♦
♦
•
• • i ♦e •
•♦
♦
11-Apr-95 20-Jul-95 28-Oct-95 5-Feb-96 15-May-96 23-Aug-96 1-Dec-96 11-Mar-97 19-Jun-97 27-Sep-97
Date
• up DO
dwn DO

260
240
220
200
LIT 180
rn
c 160
0
4-
- 140
0
U
100
`o
U 80
Morehead City WWTP Ow = 1.7 MGD
Calico Creek "SC"
Instream Chlor-a Concentration
April '95 - October '95
60
40 --
20 ■
e
♦
•
♦
♦ ■•
■
0 ♦
17-Mar-95 11-Apr-95 6-May-95 31-May-95 25-Jun-95 20-Jul-95 14-Aug-95 8-Sep-95 3-Oct-95 28-Oct-95
Date
• up chlor-a
■ dwn chlor-a
■

TP Concentration (mg/L)
3
2.5
2
1.5
1
0.5
Morehead City WWTP Qw - 1.7 MGD
Calico Creek "SC"
Instream Total Phosphorus Concentration
April '95 - October '95
♦
•
•
•
•
♦
•
■
1
$
•
♦
0
17-Mar-95
•
•
•
•
♦ up TP
■ dwn TP
11-Apr-95 6-May-95 31-May-95 25-Jun-95 20-Jul-95 14-Aug-95 8-Sep-95 3-Oct-95 28-Oct-95
Date

TN Concentration (mg/L)
16
14
12
10
0
17-Mar-95 11-Apr-95 6-May-95 31-May-95 25-Jun-95 20-Jul-95 14-Aug-95 8-Sep-95
Date
Morehead City WWTP Qw = 1.7 MGD
Calico Creek "SC"
Instream Total Nitrogen Concentration
April '95 - October '95
• ••
•
■
•
•
te
Is
El
•
✓
3-Oct-95
• upTN
■ dwn TN
28-Oct-95

Morehead City WWTP and Surrounding Waters
Newport River
Morehead City WWTP ^ _
Qw=1.7 MGD
Calico Ck. "SC" `''
,
Pogue Sound (1rtercoasfal V/ar<?r:; y)
Legend
• Minor Olschg (xlMOD)
• Major Dtschg (> MGM
Non SA waters
r SA waters
Primary Road
Municipality
® Closed Shell Fish waters
(area approximated)
ATI
DEHNR

Morehead City WWTP
NC0026611
Qw=1.7 MGD
Calico Creek "SC"
AHM
8/8/97
• Morehead City WWTP has a permit to discharge 1.7 MGD into Calico Creek, a class SC stream that
flows east into the Newport River near the Beaufort Inlet.
• The current permit limits for conventional parameters are as follows:
Monthly Average
Summer Winter
Wasteflow (MGD): 1.7
GODS (mg/1): 20.0 30.0
NH3N (mg/1): monitor monitor
DO (mg/1): 5.0 5.0
TSS (mg/1): 30.0 30.0
Fecal Col. (/100 ml): 86.0 86.0
pH (SU): 6.8-8.5 6.8-8.5
Residual Chlorine (µg/1): monitor monitor
Temperature (C): monitor monitor
TP (mg/1): monitor monitor
TN (mg/1): monitor monitor
Acute Toxicity P/F Qtrly
• Water quality violations of the state standard for dissolved oxygen and chlorophyll -a have been
occurring in Calico Creek for many years (see attached graphs). These problems have been
exacerbated by the fact that Calico Creek is poorly flushing and tidally influenced.
• Nutrients as well as oxygen consuming wastes are believed to be significant contributors to the
impair ent of Calico Creek.
• Dye studies indicate that the effluent remains in the vicinity of the discharge for at least one complete
tidal cycle.
• The City is severely limited in choices for alternative sites for a surface water discharge as most of the
major water ways surrounding the city are classified SA. The SA waters at the confluence of Calico
Creek and the Newport River are currently closed to shell fishing.
• A modeling analysis of Calico Creek was completed in 1990. Based on the modeling report removal
of the discharge was recommended in the White Oak Basinwide Plan. The report indicates that if.
removal of the dare is nat..2102fioLthen the facility should be required to meet advanced tertiary
limits including nutrient removal for nitrogen and phosphorus.

Loading Summary for Oxygen Consuming Wastes and Nutrients
Morehead City WWTP/Calico Creek "SC"
GODS
Permitted load = 284 Ib/d
Average summer load ('96) = 127 lb/d
Average annual load ('96) = 123 Ib/d
Current limit: 20 mg/L (S) / 30 mg/L (W)
At a 5 mg/Llimit load = 71 lb/d (assuming Qw = 1.7 MGD)
At a 5 mg/L limit load = 104.2 lb/d (assuming Qw = 2.5 MGD)
Ammonia
Permitted load = monitor
Average summer load = 11.3 lb/d
Average annual load = 10.81b/d
No limit in current permit
At a 2 mg/L limit load = 28.3 lb/d (assuming Qw = 1.7 MGD)
At a 1 mg/L limit load = 14.2 lb/d
(assuming Qw = 1.7 MGD)
At a 2 mg/L limit load = 41.7 lb/d (assuming Qw = 2.5 MGD)
At a 1 mg/L limit load = 20.8 lb/d (assuming Qw = 2.5 MGD)
'TP
Permitted load = monitor
Average summer load ('96) = 22.O lb/d
Average annual load ('96) = 16.91b/d
At a 2 mg/L limit load = 28.4 Ib/d (assuming Qw = 1.7 MGD)
At a 1 mg/L limit load = 14.21b/d (assuming Qw = 1.7 MGD)
At a 0.5 mg/L limit load = 7.1 lb/d (assuming Qw = 1.7 MGD)
At a 2 mg/L limit load = 41.7 lb/d (assuming Qw = 2.5 MGD)
At a 1 mg/L limit load = 20.8 lb/d (assuming Qw = 2.5 MGD)
At a 0.5 mg/L limit load = 10.4 lb/d (assuming Qw = 2.5 MGD)
TN
Permitted load = monitor
Average sum}ner load ('96) = 53.8 lb/d
Average annual load ('96) = 54.8 lb/d
At a 6 mg/L limit load = 85.O lb/d
At a 4 mg/L limit load = 56.7 lb/d
At a 2 mg/L limit load = 28.3 lb/d
At a 1 mg/L limit load = 14.2 lb/d
(assuming Qw = 1.7 MGD)
(assuming Qw = 1.7 MGD)
(assuming Qw = 1.7 MGD)
(assuming Qw = 1.7 MGD)
At a 6 mg/L limit load = 125.1 lb/d (assuming Qw = 2.5 MGD)
At a 4 mg/L 1 mit load = 83.4 lb/d (assuming Qw = 2.5 MGD)
At a 2 mg/L limit load = 41.7 lb/d (assuming Qw = 2.5 MGD)
At a 1 mg/L limit load = 20.8 lb/d (assuming Qw = 2.5 MGD)
Flow
Permitted flow = 1.7 MGD
Average summer flow ('96) = 1.523 MGD
Average annual flow ('96) = 1.404 MGD

DO Concentration (mg/L)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
Morehead City WWTP Ow = 1.7 MGD
Calico Creek "SC"
Instream Dissolved Oxygen Concentration
April 1995 - June 1997
■ ■ ■
••• ■
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• el ♦ a
■
•
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m tar
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•
•
• ♦ ♦ ■ ♦■ •
•
0
1-Jan-95 11-Apr-95 20-Jul-95 28-Oct-95 5-Feb-96 15-May-96 23-Aug-96 1-Dec-96 11-Mar-97 19-Jun-97 27-Sep-97
Date
♦up DO
■ dwn DO

Chlor-a Concentration (ug/L)
260
Morehead City WWTP Qw = 1.7 MGD
Calico Creek "SC"
Instream Chlor-a Concentration
April '95 - October '95
240
220
200
180
160
140
120
100
80
60
40 -
20
0
17-Mar-95
izi
•
♦
♦
11-Apr-95 6-May-95 31-May-95 25-Jun-95 20-Jul-95 14-Aug-95 8-Sep-95 3-Oct-95 28-Oct-95
Date
♦ up chlor-a
dwn chlor-a

TP Concentration (mg/L)
2.5
2
Morehead City WWTP Qw = 1.7 MGD
Calico Creek "SC"
Instream Total Phosphorus Concentration
April '95 - October '95
•
a
1.5 -
1
0.5
0
17-Mar-95 11-Apr-95 6-May-95 31-May-95 25-Jun-95 20-Jul-95 14-Aug-95 8-Sep-95
Date
♦
♦
♦
•
1
1
•
•
♦
e
•
$ ♦
•
a
•
♦
1
® a
■
e
■
111
■♦ 1 a
3-Oct-95 28-Oct-95
♦upTP
a dwn TP

TN Concentration (mg/L)
16
14
12
10
8
6
4
2
Morehead City WWTP Qw = 1.7 MGD
Calico Creek "SC"
Instream Total Nitrogen Concentration
April '95 - October '95
•
•
♦
•
•
■
•
a
•
■
♦
°
■
•
■
•
•
•
♦ • •
♦ ■
■
■
■
♦
■
•
• up TN
■ dwn TN
0
17-Mar-95 11-Apr-95 6-May-95 31-May-95 25-Jun-95 20-JuI-95 14-Aug-95 8-Sep-95 3-Oct-95 28-Oct-95
Date

Morehead City WWTP and Surrounding Waters
, '(' i!!rl Sound (l°)tzrc67 I.rl Viai'er;vaa) - -_
Newport r it✓er
Morehead City WWTP ^
Qw=1.7 MGD
Calico Ck. "SC"
-�-+�
1rteu.lc roan
Legend
• Minor Olschg(<1MGD)
• Major Dischg (> 1 MGD)
N Non SA waters
/V SA waters
Jr`J Primary Road
J MancipaIIty
® Closed Shell Fish wafers
(area approximated)
DEHNRATA

o
0
2
3
_0
L..
G
N
7
w
6
5
3
2
Morehead City - Flow Data
•
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it_ a 16_ . v.
44400000• 17Aterrak wwt 40i, %rob
•
_ _0
0 50 100
150
200
Time (day)
r r
250 300 350
400

BOD Concentration (mg/L)
600
500
400
300
200
100
0
Morehead City - BOD5 Data
•
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0
50
100
150
200
Time (day)
250
300
350
400
• Influent BOD
• Effluent BOD

14000.0
12000.0
10000.0
m 8000.0
a
N
ca
m 6000.0
4000.0
2000.0
0.0
Morehead City - BOD Data
Average %
95.7%
Removal
•
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0
50
100
150
200
Time (day)
250
300
350
400
• Influent BOD
■ Effluent BOD

20
18
16
14
•
Morehead City - NH-3 Data
J
1
Q)
E
c 12
0
fl -
Y
N
c 10
.
0
0
z
c.- 8 -
v
m
w
6-
4
2
0
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♦♦♦♦♦ •
♦♦♦♦
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♦♦♦♦♦♦♦
♦
•♦♦♦♦♦
•
♦♦♦♦♦♦♦
♦♦♦♦♦♦♦♦♦♦♦♦♦
•
♦♦♦♦♦♦♦
♦♦
♦
0
10
20
30
40
50
Time (day)
60
70
80
90

800.0
700.0
600.0
500.0
:
co
Ts
z
0 400.0
m
CD
E
w
300.0
200.0
100.0
Morehead City - BODu Data
♦
♦
•
•
0.0
Oct-95
Feb-96 May-96
Aug-96 Dec-96
Month
Mar-97
Jun-97 Sep-97
♦ BODu Existing
—*—BODu Permitted
BODu Expansion