NC0086665_Permit modification_20010105

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
Ms. Starla Lacy, Environmental Specialist
Rockingham Power LLC
1000 Louisiana, Suite 5800
Houston, Texas 77002-5050
&1711.
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL. RESOURCES
January 5, 2001
Subject: NPDES Permit Issuance
Permit Number NC0086665
Combustion Turbine Facility
Rockingham County
Dear Ms. Lacy
The Division issued NPDES permit NC0086665 to Dynegy, Incorporated on November 19, 1999. The
Division has reviewed your request for permit modification at the subject facility. Specifically, you requested a
modification to the chronic toxicity testing requirement. In accordance with your permit modification request, the
Division is forwarding herewith a modification to the subject permit. The chronic toxicity requirement has been
replaced with an acute toxicity requirement. Please review the conditions of the modification carefully.
Enclosed please find the modified effluent limitation pages. These pages should be inserted into your
permit and the old ones discarded. This permit modification 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.
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 Water Quality or permits required
by the Division of Land Resources, Coastal Area Management Act or any other Federal or Local government
permit that may be required.
If any parts , measurement frequencies or sampling requirements contained in this permit modification
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 a written petition conforming to chapter 150B of the
North Carolina General Statutes, 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.
If you have any questions concerning this permit, please contact Mr. Michael Myers at telephone number
[phone], extension 508.
cc: NPDES Permit File
Fayetteville Regional Office
Aquatic Toxicology Unit
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
An Equal Opportunity Affirmative Action Employer
S' cerely
feL.4err T. Stevens
Telephone [phone] FAX [phone]
VISIT US ON THE INTERNET @ http://h20.enr.state.nc.uS/NPDES

A (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - FINAL
Permit No. NC0086665
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 - Evaporative Cooling Water and Contact Stormwater. Such discharges shall be limited and monitored by the Permittee as specified below:
EFFLUENT CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Effluent Measurement
Frequency
Sample
Type
Sample
Location1
Monthly
Average
Weekly Average
Daily Maximum
Flow (MGD)
Monthly
See Note 1
Effluent
Total.Suspended Solids
45.0 mg/L
Monthly
Grab
Effluent
Total Residual Chlorine
17 µg/L
Monthly
Grab
Effluent
Turbidity
Monthly
Grab
Effluent
Temperature'
Monthly
Grab
Effluent
Oil and Grease3
Monthly
Grab
Effluent
EPA Methods 624/625'
Semi -Annually
Grab
Effluent
Acute Toxicity'
Variable'
Grab
Effluent
pH'
Monthly
Grab
Effluent
THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN OTHER THAN TRACE AMOUNTS.
NOTES:
Sample Locations: Effluent shall be defined as a point after combination of the evaporative cooling water and the contact stormwater prior to discharge to the unnamed tributary
to Jacob's Creek. Where no measurable discharge occurs, "no discharge" should be clearly noted on the submitted monthly discharge monitoring report. Flow may be monitored
in one of the four following ways:
a) Measure flow continuously;
b) Calculate flow based on the area draining to the outfall, the built upon area, and the total rainfall;
c) Estimate by flow measurement at 20 minute intervals during the entire discharge event; or
d) Base flow on pump logs.
2 The temperature of the effluent shall not cause the temperature of the receiving stream to increase by more than 2.8 degrees C above natural water temperature, and in no case
cause the temperature of the receiving stream to exceed 32 degrees C.
3 Where possible, the grab sample for oil and grease shall be skimmed from the surface of a quiescent zone.
4 After a compliance history associated with 8 to 12 sampling events has been established, the permittee may request relaxation or deletion of this monitoring requirement.
5 Acute Toxicity (Fathead Minnow, 24-hour) Monitoring, Episodic; see Condition A(2) of this permit.
6 During the first calendar year of the permit, the testing will be performed upon the first discharge from the facility during each two month period, the periods defined as the
months of January -February, March -April, May -June, July -August, September -October, and November -December.
' The pH shall not be less than 6.0 standard units or greater than 9.0 standard units.

ACUTE TOXICITY MONITORING (EPISODIC)
The permittee shall conduct acute toxicity tests using protocols defined as definitive in E.P.A.
Document EPA/600/4-90/027 entitled "Methods for Measuring the Acute Toxicity of Effluents to
Freshwater and Marine Organisms." The monitoring shall be performed as a Fathead Minnow
(Pimephales promelas) 24 hour static test. Effluent samples for self -monitoring purposes must be
obtained below all waste treatment. During the first calendar year of the permit, the testing will be
performed upon the first discharge from the facility during each two month period, the periods
defined as the months of January -February, March -April, May -June, July -August, September -
October, and November -December. After the first calendar year, the permittee will conduct one test
annually, with the annual period beginning in January of the next calendar year. The annual test
requirement must be performed and reported by June 30. If no discharge occurs by June 30,
notification will be made to the Division by this date. Toxicity testing will be performed on the next
discharge event for the annual test requirement.
The parameter code for this test is TAE6C. All toxicity testing results required as part of this permit
condition will be entered on the Effluent Discharge Form (MR-1) for the month in which it was
performed, using the appropriate parameter code. Additionally, DWQ Form AT-1 (original) is to be
sent to the following address:
Attention: North Carolina Division of Water Quality
Environmental Sciences Branch
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Branch no
later than 30 days after the end of the reporting period for which the report is made.
Test data shall be complete and accurate and include all supporting chemical/physical measurements
performed in association with the toxicity tests, as well as all dose/response data. Total residual
chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for
disinfection of the waste stream.
Should there be no discharge of flow from the facility during a period in which toxicity monitoring is
required, the permittee will complete the information located at the top of the aquatic toxicity (AT)
test form indicating the facility name, permit number, pipe number, county, and the month/year of
the report with the notation of "No Flow" in the comment area of the form. The report shall be
submitted to the Environmental Sciences Branch at the address cited above.
Should any test data from either these monitoring requirements or tests performed by the North
Carolina Division of Water Quality indicate potential impacts to the receiving stream, this permit
may be re -opened and modified to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum
control organism survival and appropriate environmental controls, shall constitute an invalid test and
will require immediate follow-up testing to be completed no later than the last day of the month
following the month of the initial monitoring.
EAM Fathead 24 Version 9/96

Rockingham Power 86665
/14T5
Subject: Rockingham Power 86665
Date: Tue, 15 Aug 2000 09:14:48 -0400
From: Kristie Robeson <[e-mail]>
To: Charles Weaver <[e-mail]>, [e-mail]
CC: Matt Matthews <[e-mail]>
The facility sent a letter to Tommy dated 8/4 requesting a permit
modification changing their tox test type. However, they attached the
incorrect tox template to their letter. To avoid further confusion on
this one, Charles, I wanted to let you know to still use the tox
template that I sent you on August 4th. I have attached here a copy of
that language. I hope this permit will soon go away.
Thanks for your patience and help.
';7.1. Rockingham PowerLLC.doc
Name: Rockingham PowerLLC.doc
Type: WINWORD File (application/msword)
Encoding: base64
Download Status: Not downloaded with message
1 of 1 8/15/2000 3:38 PM

1
MEMORANDUM
TO:
DIVISION OF WATER QUALITY
Dave Goodrich
THROUGH: Matt Matthews (1'
FROM: Kristie Robeson
SUBJECT:
August 4, 2000
Permit Modification
Rockingham Power, L.L.C.
NPDES Permit No. NC0086665
Rockingham County
s 5 [ 5
1 AUG 1 0 2000
DENR - WATER QUALITY
POINT SOURCE PRANCH
In a memo dated August 3, 2000, our office requested that this facility's permit be
modified to include an acute toxicity test as opposed a chronic toxicity test. Attached to
that memo was toxicity test condition language which required the facility to conduct five
acute toxicity tests and then one annually thereafter. During further discussions with the
facility, ATU and the facility agreed that for the first calendar year the facility should
conduct testing during each two -month period and then one time annually thereafter.
These two -month periods would be defined as January -February, March -April, May -
June, July -August, September -October, and November -December. Both ATU and
Rockingham Power felt that toxicity testing conducted in this frequency would produce
more meaningful toxicity data based on the nature of this discharge. Please find attached,
a copy of the toxicity test language to be included in Rockingham Power's permit
modification.
Our office appreciates your assistance to undertake the necessary steps to modify
the existing permit and incorporate the recommendation cited above. Should you have
any questions, please feel free to contact me at 733-2136.
Attachment
cc: Dave Russell-WSRO
Starla Lacy -Rockingham Power LLC
Charles Weaver-NPDES Permit Unit
ATU Facility Files
Central Files

ACUTE TOXICITY MONITORING (EPISODIC)
The permittee shall conduct acute toxicity tests using protocols defined as definitive in E.P.A.
Document EPA/600/4-90/027F entitled "Methods for Measuring the Acute Toxicity of Effluents
to Freshwater and Marine Organisms." The monitoring shall be performed as a Fathead Minnow
(Pimephales promelas) 24 hour static test. Effluent samples for self -monitoring purposes must be
obtained below all waste treatment. During the first calendar year of the permit, the testing will
be performed upon the first discharge from the facility during each two -month period, the
periods defined as the months of January -February, March -April, May -June, July -August,
September -October, and November -December. After the first calendar year, the permittee will
conduct one test annually, with the annual period beginning in January of the next calendar year.
The annual test requirement must be performed and reported by June 30. If no discharge occurs
by June 30, notification will be made to the Division by this date. Toxicity testing will be
performed on the next discharge event for the annual test requirement.
The parameter code for this test is TAE6C. All toxicity testing results required as part of this
permit condition will be entered on the Effluent Discharge Form (MR-1) for the month in which
it was performed, using the appropriate parameter code. Additionally, DWQ Form AT-1
(original) is to be sent to the following address:
Attention: Environmental Sciences Branch
North Carolina Division of
Water Quality
1621 Mail Service Center
Raleigh, N.C. 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Branch
no later than 30 days after the end of the reporting period for which the report is made.
Test data shall be complete and accurate and include all supporting chemical/physical
measurements performed in association with the toxicity tests, as well as all dose/response data.
Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine
is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a period in which toxicity
monitoring is required, the permittee will complete the information located at the top of the
aquatic toxicity (AT) test form indicating the facility name, permit number, pipe number, county,
and the month/year of the report with the notation of "No Flow" in the comment area of the
form. The report shall be submitted to the Environmental Sciences Branch at the address cited
above.
Should any test data from either these monitoring requirements or tests performed by the North
Carolina Division of Water Quality indicate potential impacts to the receiving stream, this permit
may be re -opened and modified to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum
control organism survival and appropriate environmental controls, shall constitute an invalid test
and will require immediate follow-up testing to be completed no later than the last day of the
month following the month of the initial monitoring.

Ova.ries
DIVISION OF WATER QUALITY
August 3, 2000
MEMORANDUM
TO: Dave Goodrich
THROUGH: Matt Matthews ' PN
FROM: Kristie Robeson la/
SUBJECT: Permit Modification
Rockingham Power, L.L.C.
NPDES Permit No. NC0086665
Rockingham County
AUG - 7 2000
1
DENR - WATER QUALITY
POINT S011:4CEr. BRAF1CH
By cover letter dated November 19, 1999 the subject facility was issued NPDES
Permit No. NC0086665 with an effective date of January 1, 2000, and expiration date of
April 30, 2002. Upon discussions with the Winston-Salem Regional Office and the
facility, we were informed that the toxicity test in this permit is inappropriate for this type
discharge. This facility is permitted for a chronic toxicity test at 90%. Personnel from
- the facility and WSRO informed our unit that this discharge is intermittent. Therefore, the
chronic test which requires collection of two samples would be impossible to conduct.
Based on the nature of this discharge, our office recommends that this permit be modified
to include a 24 hour LC50 acute monitoring requirement. The test organism should be
fathead minnow and the testing frequency should be for the facility to conduct five
toxicity tests during the first five discrete discharge events and then once annually
thereafter. The facility and WSRO concur with our recommendation. Please find
attached a copy of the correct toxicity language to include in this permit modification.
Our office appreciates your assistance to undertake the necessary steps to modify
the existing permit and incorporate the recommendation cited above. Should you have
any questions, please feel free to contact me at 733-2136.
Attachment
cc: Dave Russell-WSRO
Starla Lacy -Rockingham Power LLC
Charles Weaver-NPDES Permit Unit
ATU Facility Files
Central Files

ACUTE TOXICITY MONITORING (EPISODIC)
The permittee shall conduct FIVE acute toxicity tests using protocols defined as definitive in E.P.A.
Document EPA/600/4-90/027 entitled "Methods for Measuring the Acute Toxicity of Effluents to
Freshwater and Marine Organisms." The monitoring shall be performed as a Fathead Minnow (Pimephales
promelas) 24 hour static test. Effluent samples for self -monitoring purposes must be obtained below all
waste treatment. Sampling and subsequent testing will occur during the first five discrete discharge events
after the effective date of this permit. After monitoring of the first five toxicity tests, the permittee will
conduct one test annually, with the annual period beginning in January of the next calendar year. The annual
test requirement must be performed and reported by June 30. If no discharge occurs by June 30, notification
will be made to the Division by this date. Toxicity testing will be performed on the next discharge event for
the annual test requirement.
The parameter code for this test is TAE6C. All toxicity testing results required as part of this permit
condition will be entered on the Effluent Discharge Form (MR-1) for the month in which it was performed,
using the appropriate parameter code. Additionally, DWQ Form AT-1 (original) is to be sent to the
following address:
Attention: Environmental Sciences Branch
North Carolina Division of
Water Quality
1621 Mail Service Center
Raleigh, N.C. 27699-1621
Test data shall be complete and accurate and include all supporting chemical/physical measurements
performed in association with the toxicity tests, as well as all dose/response data. Total residual chlorine of
the effluent toxicity sample must be measured and reported if chlorine is employed for disinfection of the
waste stream.
Should any test data from either these monitoring requirements or tests performed by the North Carolina
Division of Water Quality indicate potential impacts to the receiving stream, this permit may be re -opened
and modified to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control
organism survival and appropriate environmental controls, shall constitute an invalid test and will require
immediate follow-up testing to be completed no later than the last day of the month following the month of
the initial monitoring.
EAM Fathead 24 Version 9/96

• -AUG-•08-2000 TUE 10:55 AM
FAX NO, P. 01
State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
DENRAtt-77C111
Division of Water Quality
Environmental Sciences Branch & Wetlands/401 Unit
Location; /1 101 Reedy Creek Road
Raleigh, N.C. 27607
Mailing Address; 1621 Mail Service Center
Raleigh, N.C. 27699
FAX: [phone]
FAX TO: C.Ll__,ev
FAX NUMBER:
FROM:
PHONE:
I NO. OF PAGES INCLUDING THIS SHEET: 3
) q-LoryN ovviiv\--k.)-(j
teittl-ct ate too-
1�'1Z,
If you receive this fax by mistake call: ESB [phone] or Wetlands [phone].

• • AUCr-08-2000 TUE 10:55 AM FAX NO, P. 02
DIVISION OF WATER QUALITY
August 4, 2000
MEMORANDUM
TO: Dave Goodrich
THROUGH: Matt Matthews {f'
FROM: Kristie Robeson
SUBJECT: Permit Modification
Rockingham Power, L.L.C.
NPDES Permit No. NC0086665
Rockingham County
In a memo dated August 3, 2000, our office requested that this facility's permit be
modified to include an acute toxicity test as opposed a chronic toxicity test. Attached to
that memo was toxicity test condition language which mquircd the facility to conduct five
acute toxicity tests and then one annually thereafter. During further discussions with the
facility, ATII and the facility agreed that for the first calendar year the facility should
conduct testing during each two -month period and then one time annually thereafter.
These two -month periods would be defined as January -February, March -April, May -
June, July -August, September -October, and November -December, Bath AT(J and
Rockingham Power felt that toxicity testing conducted in this frequency would produce
more meaningful toxicity data based on the nature of this discharge, Please find attached,
a copy of the toxicity test language to be included in Rockingham Power's permit
modification.
Our office appreciates your assistance to undertake the necessary steps to modify
the existing permit and incorporate the recommendation cited above. Should you have
any questions, please feel free to contact me at 733-2136.
Attachment
cc: Dave Russell-WSRO
Starla Lacy -Rockingham Power LLC
Charles Wcaver-NPDES Permit Unit
ATU Facility Files
Conlral Files

AUG-08-2000 TUE 10:56 AM
FAX NO, P. 03
ACUTE TOXICITY MONITORING (EPISODIC)
The permittee shall conduct acute toxicity tests using protocols defined as definitive in R.P.A.
Document EPA/600/4-90/027F entitled "Methods for Measuring the Acute Toxicity of Effluents
to Freshwater and Marine Organisms." The monitoring shall be performed as a Fathead Minnow
(Pinnephales promelas) 24 hour static test. Effluent samples for self -monitoring purposes must be
obtained below all waste treatment. During the first calendar year of the permit, the testing will
be performed upon the first discharge from the facility during each two -month period, the
periods defined as the months of January -February, March -April, May -June, July -August,
September -October, and November -December. After the first calendar year, the perrnittee will
conduct one test annually, with the annual period beginning in January of the next calendar year.
The annual test requirement must be performed and reported by June 30. If no discharge occurs
by June 30, notification will be made to the Division by this date. Toxicity testing will be
performed on the next discharge event for the annual test requirement.
The parameter code for this test is TAEGC. All toxicity testing results required as part of this
permit condition will he entered on the Effluent Discharge Form (MR-1) for the month in which
it was performed, using the appropriate parameter code. Additionally, DWQ Form AT-1
(original) is to be sent to the following address:
Attention: Environmental Sciences Branch
North Carolina Division of
Water Quality
1621 Mail Service Center
Raleigh, N.C. 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences 13ranch
no ]rater than 30 days after the end of the reporting period for which the report is made.
Test data shall be complete and accurate and include all supporting chemical/physical
measurements performed in association with the toxicity tests, us well as all dosciresponsc data.
Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine
is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a period in which toxicity
monitoring is required, the permittce will complete the information located at the top of the
aquatic toxicity (AT) test form indicating the facility name, permit number, pipe number, county,
and the month/year of the report with the notation of "No Flow" in the comment area of the
form. The report shall be submitted to the Enviroimiental Sciences Branch at the address cited
above.
Should any test data from either these monitoring requirements or tests performed by the North
Carolina Division of Water Quality indicate potential impacts to the receiving stream, this permit
may he re -opened and modified to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum
control organism survival and appropriate environmental controls, shall constitute an invalid test
and will require immediate follow-up testing to be completed no later than the last day of the
month following the month of the initial monitoring.

ROCKINGHAM POWER, L.L.0 RECEIVED
1000 Louisiana, Suite 5800 N C• DPfit. Of Ei-1NR
Houston, Texas 77002-5050
[phone]
July 31, 2000
AUG - 2 2000
Winston-Salem
Regional Office
Mr. David Russell
North Carolina Department of Environment and Natural Resources
Division of Water Quality -Winston-Salem Regional Office
585 Waughtown Street
Winston-Salem, North Carolina 27107 } �'
RE: Request for Clarification G
Rockingham Power, L.L.C., Reidsville, NC
NPDES Permit No. NC0086665
Dear Mr. Russell:
2000
T —T
wattR QUALITY
r „tiY sol '; C,r. BRANCH
As discussed with you verbally, Rockingham Power (the Facility) is seeking clarification
regarding the Toxicity testing requirement associated with the above referenced NPDES
permit. We understand through discussion with you that the Chronic Toxicity
requirement may not be appropriate for the facility, given the intermittent nature of its
water discharge. You had mentioned that the Acute Toxicity test might be better suited
as a requirement for a facility with an intermittent discharge. As well, we understand that
the frequency associated with an Acute Toxicity test would be five tests conducted in
sequence, switching to an annual requirement, pending satisfactory results.
At your direction, the Facility has not collected a discharge sample specifically intended
for toxicity testing to date. Therefore, at this time we respectfully request a determination
from NCDENR as to the best applicable toxicity test and associated frequency for
inclusion into the Facility's NPDES permit, after which we will collect a sample for
analysis.
Please do not hesitate to contact me at [phone] or Barbara Irwin at (217) 872-
2363 if you have any questions.
Yours truly,
Starla Lacy
Environmental Specialist
Cc: Barbara Irwin