NC0026051_Permit Modification_19930430

1
State of North Carolina
Department of Environment, Health and Natural Resources
Division of Environmental Management
512 North Salisbury Street • Raleigh, North Carolina 27604
James B. Hunt, Jr. Jonathan B. Howes
Govenor Secretary
April 30, 1993
Mr. George R. Shaw, P.E.
County of Durham
200 E. Main Street
Durham, NC 27701
Subject: NPDES No. NC0026051
Triangle WWTP
Permit Modification Request
Durham County
Dear Mr. Shaw:
In accordance with your request originally dated June 3, 1992, we are forwarding
herewith the subject permit. The only changes in this permit are in modifying the cadmium,
chromium, nickel, lead, cyanide, and mercury monitoring requirements from "weekly" to
"daily," and modifying the effluent limitations for these parameters as outlined in the letter to
Mr. Doug Cullinane dated October 8, 1990. We also updated the permit to current DEM
regulations. This permit is issued pursuant to the requirements of North Carolina General
Statute 143-215.1 and the Memorandum of Agreement between North Carolina and the U. S.
Environmental Protection Agency dated December 6, 1983.
If any parts, measurement frequencies or sampling requirements contained in this
permit are unacceptable to you, you have the right to an adjudicatory hearing upon written
request within thirty (30) days following receipt of this letter. This request must be in the
form of a written petition, conforming to Chapter 150E of the North Carolina General Statutes,
and filed with the Office of Administrative Hearings, Post Office Drawer 27447, Raleigh, North
Carolina 27611-7447. Unless such demand is made, this decision shall be final and binding.
Please take notice that this permit is not transferable. Part II, E.4. addresses the
requirements to be followed in case of change in ownership or control of this discharge.
This permit does not affect the legal requirement to obtain other permits which may be
required by the Division of Environmental Management or permits required by the Division of
Land Resources, Coastal Area Management Act or any other Federal or Local governmental
permit that may be required.
Pollution Prevention Pays
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone]
An Equal Opportunity Affirmative Action Employer

Page 2
April 30, 1993
Durham County
If you have any questions concerning this permit, please contact Susan Robson at telephone
number 919/733-5083.
SinyTely,
reston Ho
Director
cc: Mr. Jim Patrick, EPA
Raleigh Regional Office
Compliance
Central Files
Technical Support Branch
Kim Brantley
, Jr., P.E.

Permit No. NC0026051
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT, HEALTH, AND NATURAL RESOURCES
DIVISION OF ENVIRONMENTAL MANAGEMENT
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215.1,
other lawful standards and regulations promulgated and adopted by the North Carolina Environmental
Management Commission, and the Federal Water Pollution Control Act, as amended,
Durham County
is hereby authorized to discharge wastewater from a facility located at
Triangle WWTP
NC Highway 55 and NCSR 2028
west of Research Triangle Park
Durham County
to receiving waters designated as Northeast Creek in the Cape Fear River Basin
in accordance with effluent limitations, monitoring requirements, and other conditions set forth in
Parts I, II, and III hereof.
This permit shall become effective April 30, 1993
This permit and the authorization to discharge shall expire at midnight on February 29, 1996
Signed this day April 30, 1993
Original Signed By
Coleen H. Sullins
A. Preston Howard, Jr., P.E., Director
Division of Environmental Management
By Authority of the Environmental Management Commission

Permit No. NC0026051
SUPPLEMENT TO PERMIT COVER SHEET
Durham County
is hereby authorized to:
1. Continue to operate the existing wastewater treatment facility consisting of dual train: extended
aeration, clarifier, chlorination and tertiary filters located at Triangle WWTP, NC Highway 55
and NCSR 2028, west of Research Triangle Park, Durham County (See Part III of this
Permit), and
2. Discharge from said treatment works at the location specified on the attached map into Northeast
Creek which is classified Class C-NSW waters in the Cape Fear River Basin.

1689
QUADRANGLE LOCATION
J.
.
�\•
egg • • INTERIOR —GEOLOGICAL 5URVEV,8IESTON, VIRGINIA-1987
1y 9 Ml. TO U.S. 64 691°Mm.E,
ROAD CLASSIFICATION
Primary highway,
hard surface_...._ ...
Secondary highway,
hard surface__ .. _ — — Unimproved road
0 Interstate Route
55'
3976
3975
yQ
CC
3974
3973002in4N.
-Dv-R kc.t Cow1J
—7Nr%IA).LTVP
_+_35°52'30"
78°52'30"
Light -duty road, hard or
improved surface
U. S. Route () State Route
SOUTHWEST DURHAM, N. C.
NW/4 DURHAM SOUTH 15' OUADRANOLE
35078-H8-TF-024
MASTER f 1LE
Sions shown in purple and woodland compiled in cooperation
State of North Carolina agencies from aerial photographs taken
4 and other sources. This information not field checked. Map edited 1987
Ile tint indicates extension of urban areas
1973
PHOTOREVISED 1987
DMA 5255 IV NW -SERIES V842

A. (). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS SUMMER (April 1 - October 31) Permit No. NC0026051
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from
outfall(s) serial number 001. Such discharges shall be limited and monitored by the permittee as specified below:
Effluent Characteristics Discharge Limitations Monitoring Requirements
Measurement Sample *Sample
Monthly Avg, Weekly Avg, Pally Max Freauency Tvpe Location
Flow 6.0 MCA Continuous Recording I or E
BOD, 5 day, 20°C** 5.0 mg/I 7.5 mg/I Daily Composite E, I
Total Suspended Residue** 30.0 mg/I 45.0 mg/I Daily Composite E, I
NH3 as N 1.0 mg/I Daily Composite E
Dissolved Oxygen*** Daily Grab E, U, D
Fecal Coliform (geometric mean) 200.0 /100 ml 400.0 /100 ml Daily Grab E, U, D
Total Residual Chlorine Daily Grab E
Temperature Daily Grab E,U,D
Total Nitrogen (NO2 + NO3 + TKN) Monthly Composite E
Total Phosphorus 0.5 mg/1**** Weekly Composite E
Chronic Toxicity Quarterly Composite E
*Sample locations: E - Effluent, I - Influent, U - Upstream at NCSR 1102, D - Downstream at (1) NCSR 1100 and (2) NCSR 1732
Upstream and downstream samples shall be grab samples. Stream samples shall be collected for temperature, dissolved oxygen, fecal
coliform, and conductivity three times per week during June, July, August, and September and once per week during the remaining months of
the year. All other stream sampling shall be conducted during June, July, August, and September only.
**The monthly average effluent BODS and Total Suspended Residue concentrations shall not exceed 15 % of the respective influent value (85
%) removal.
*** The daily average dissolved oxygen effluent concentration shall not be less than 6.0 mg/l.
**** Quarterly average limit
***** Chronic Toxicity (Ceriodaphnia) P/F at 90%; February, May, August and November, See Part III, Condition H.
******See Part III, Condition G.
If the first daily samples for cadmium, chromium, nickel, lead, cyanide, and mercury are in compliance with the weekly averages for those
parameters, the rest of the daily samples do not need to be analyzed. If the limits are not met at first, then the rest of the daily samples should
be analyzed and reported.
The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored daily at the effluent by grab sample.
There shall be no discharge of floating solids or visible foam in other than trace amounts.

A. (). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS SUMMER (April 1 - October 31) Permit No. NC0026051
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from
outfall(s) serial number 001. (Continued)
Effluent Characteristics
Pollutant Analysis
Conductivity
Cadmium
Chromium
Nickel
Lead
Cyanide
Mercury
Copper
Silver
Zinc
Total Phosphorus'
PO4'
TKN'
NO2 + NO3*
NH3 as N'
pH'
Discharge Limitations
Units (specify)
Monthly Avg, Weekly Avg.
2.0 µg/I
50.0 p.g/I
88.0 µg/I
25.0 µg/I
5.0 µg/I
0.012 µg/I
Daily Max
5.0 µg/I
200.0 µg/I
352 µg/I
34.0 µg/I
15.0 µg/I
0.048 µg/I
Monitoring
Measurement
Requirements
Sample
Freauency Type
Annually
Daily
Daily
Daily
Daily
Daily
Daily
Monthly
Monthly
Monthly
Weekly
Weekly
Weekly
Weekly
Weekly
3/Week
*Sample
Location
E
Grab U, D
Composite E
Composite E
Composite E
Composite E
Grab E
Composite E
Composite E
Composite E
Composite E
Grab U,D
Grab U,D
Grab U,D
Grab U,D
Grab U,D
Grab U,D

A. ( ). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS WINTER (November 1 - March 31) Permit No. NC0026051
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from
outfall(s) serial number 001. Such discharges shall be limited and monitored by the permittee as specified below:
Effluent Characteristics
Discharge Limitations
Monthly Avg,
Flow 6.0 MOD
BOD, 5 day, 20°C" 10.0 mg/I
Total Suspended Residue** 30.0 mg/I
NH3asN 1.8 mg/I
Dissolved Oxygen*"
Fecal Coliform (geometric mean) 200.0 /100 ml
Total Residual Chlorine
Temperature
Total Nitrogen (NO2 + NO3 + TKN)
Total Phosphorus
Chronic Toxicity
2.0 mg/I****
Weekly Avg, Daily Max
15.0 mg/I
45.0 mg/I
400.0 /100 ml
Monitoring
Measurement
Frequency
Continuous
Daily
Daily
Daily
Daily
Daily
Daily
Daily
Monthly
Weekly
Quarterly
Requirements
Sample
Tyne
Recording
Composite
Composite
Composite
Grab
Grab
Grab
Grab
Composite
Composite
Composite
*Sample
Location
I or E
E, I
E, I
E
E, U, D
E, U, D
E
E,U,D
E
E
E
*Sample locations: E - Effluent, I - Influent, U - Upstream at NCSR 1102, D - Downstream at (1) NCSR 1100 and (2) NCSR 1732
Upstream and downstream samples shall be grab samples. Stream samples shall be collected three times per week during June, July, August,
and September and once per week during the remaining months of the year.
**The monthly average effluent BOD5 and Total Suspended Residue concentrations shall not exceed 15 % of the respective influent value (85
%) removal.
*** The daily average dissolved oxygen effluent concentration shall not be less than 6.0 mg/l.
**** Quarterly average limit
***** Chronic Toxicity (Ceriodaphnia) P/F at 90%; February, May, August and November, See Part III, Condition H.
******See Part III, Condition G.
If the first daily samples for cadmium, chromium, nickel, lead, cyanide, and mercury are in compliance with the weekly averages for those
parameters, the rest of the daily samples do not need to be analyzed. If the limits are not met at first, then the rest of the daily samples should
be analyzed and reported.
The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored daily at the effluent by grab sample.
There shall be no discharge of floating solids or visible foam in other than trace amounts.

A. (). E1-I,LUENT LIMITATIONS AND MONITORING REQUIREMENTS WINTER (November 1 - March 31) Permit No. NC0026051
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from
outfall(s) serial number 001. (Continued)
Effluent Characteristics
Pollutant Analysis
Conductivity
Cadmium
Chromium
Nickel
Lead
Cyanide
Mercury
Copper
Silver
Zinc
Discharge Limitations
Units (speclfyl
Monthly Avg, Weekly Avg,
2.0 p.g/I
50.0 p.g/I
88.0 p.g/I
25.0 p.g/I
5.0 µg/I
0.012 µg/I
Pally Max
5.0 p.g/I
200.0 p.g/I
352 p.g/I
34.0 p.g/I
15.0 µg/I
0.048 µg/I
Monitoring
Measurement
Frequency
Annually
Daily
Daily
Daily
Daily
Daily
Daily
Monthly
Monthly
Monthly
Requirements
Sample
Type
Grab
Composite
Composite
Composite
Composite
Grab
Composite
Composite
Composite
Composite
*Sample
Location
E
U, D
E
E
E
E
E
E
E
E
E

DURHAM COUNTY TRIANGLE WWTP
1990-1991 DISSOLVED OXYGEN DATA
MONTH
EFFLUENT
UPSTREAM
DOWN 1
DOWN 2
JAN
8.1
8.3
9.2
9.7
FEB
8.4
10.5
10.7
9.5
MAR
8.6
10.6
8.7
9.9
APRIL
8.0
6.3
6.6
6.8
MAY
7.2
6.5
6.6
6.9
JUNE
6.8
3.8
5.3
6.7
JULY
6.6
1.5
4.5
6.2
AUG
6.7
3.1
5.9
6.7
SEPT
7.3
1.0
6.1
7.1
OCT
7.8
4.9
6.0
7.2
NOV
8.6
5.9
6.4
8.8
DEC
7.1
9.1
8.9
8.9
JAN
5.8
10.9
10.6
11.4
FEB
7.7
10.4
10.2
9.6
MAR
8.2
10.0
9.5
9.8
APRIL
8.3
6.6
6.9
7.6
MAY
7.0
4.7
5.5
6.5
JUNE
7.2
3.3
5.7
6.6
JULY
8.8
2.7
5.6
6.1
AUG
7.3
4.3
5.7
6.4
1990-1991 TOTALPHOSPHORUSDATA
MONTH
EFFLUENT
UPSTREAM
DOWN 1
DOWN 2
JAN
0.9
0.1
0.4
0.2
FEB
1.0
0.2
0.4
0.2
MAR
0.8
0.1
0.4
0.3
APRIL
0.8
0.2
0.4
0.3
MAY
0.9
0.2
0.4
0.3
JUNE
1.3
0.2
1.1
0.8
JULY
1.8
0.2
1.5
1.4
AUG
1.6
0.2
1.3
1.2
SEPT
1.4
0.2
1.2
1.2
OCT
1.2
0.2
0.6
1.2
NOV
1.1
0.2
0.6
0.7
DEC
1.2
0.2
0.5
0.3
JAN
0.5
0.2
0.3
0.2
FEB
0.5
0.1
0.3
0.3
MAR
0.6
0.2
0.4
0.4
APRIL
1.2
0.2
0.7
0.5
MAY
1.8
0.2
1.0
1.1
JUNE
1.3
0.2
0.9
1.0
JULY
0.4
0.3
0.4
0.4
AUG
1.2
0.2
1.0
1.0

12
10
8
6
4
2
0
1990-1991 DISSOLVED OXYGEN DATA
JAN
FEB
MAR
APRIL
MAY JUNE JULY
_� DOWNSTREAM 1
•
I 1 1
AUG SEPT OCT NOV DEC JAN FEB MAR APRIL MAY JUNE JULY AUG
1990-1991
• PLANT EFFLUENT _.__ UPSTREAM
DOWNSTREAM 2

TOTAL P (MG/L)
2
1.5
0.5
0
1990-1991 TOTAL PHOSPHORUS
JAN
FEB MAR APRIL MAY JUNE JULY AUG SEPT OCT NOV DEC JAN FEB MAR APRIL MAY JULY
JUNE AUG
1990-1991
PLANT EFFLUENT
DOWNSTREAM 1
UPSTREAM
DOWNSTREAM 2