DEQp00020440

Mr. Michael E. Johnson
Environmental Manager
DuPont Fluoroproducts
22828 NC Highway 87 W
Fayetteville, North Carolina 28306-7332
Dear Mr. Johnson:
Michael F. Easley, Governor
North Carolina Department of EnviroWilliam G. ROSS Jr., secretary
nment and Natural Resources
December 7, 2007
Subject: Relocation of Effluent Discharge
Permit No. NC0003573
Bladen County
Coleen H. Sullins, Director
Division of Water Quality
This letter is in response to your request for an initial determination on the proposed
discharge from the DuPont facility. A QUAL2K model was developed b
of relocating the discharge from downstream of Lock &Dam 3 to upstream M t relocation of the
Modeling and TMDL Unit reviewed the Y upstream
o Hill L evaluate the effect
relocation will not affect the dissolved oxygen QUAL2K report and concurs with the e conclusion ock Dthat the
permit modification request to relocate the discharge. in the Cape Fear River. Dupont can proceed with a
Should you have any questions NPDESe
rmitting requirements, please feel free to contact Teresa
Rodriguez at [phone], extension 553
Sincerely,
Gil Vinzani
East NPDES Unit Supervisor
cc: NPDES files
Fayetteville Regional Office - Surface Water Protection
Orth Carolina ni„ c — „; %A-- 7
nternet: h2o.enr.state.nc.us "uaiity 1617 Mail Service Center Raleigh, NC 27699-1617
512 N. Salisbury St. Phone [phone]
Raleigh, NC 27604 FAX [phone] Customer Service
1-877-623-6748

Re: Relocati,on - NPDES # NC0003573
Subject: Re: Relocation - NPDES # NC0003573
From: Adugna Kebede <[e-mail]>
Date: Wed, 28 Nov 2007 12:20:59 -0500
To: Teresa Rodriguez <[e-mail]>
Hi Teresa,
How are you? My concern is a more general one. The QUAL2E model was calibrated using the data from 1999.
And using the most current data for calibration will give a more realistic estimate of DO level under the
current condition. In some cases when the model is recalibrate using current data (especially when there is
major change in hydrology or hydraulics) we get different results. Therefore, it is always safe and
reasonable to list the limitations (both model limitation and data limitations) when doing the assessment.
if future modeling using a completely different (or most current) dataset gives us a completely different
set of results we should be able to revise our assessment. I hope this will help. Please let me know if you
have any further question.
Thanks.
Adugna
Teresa Rodriguez wrote:
Adugna, I am going to write a letter
concerned with the use of 1999 data.
them to address it.
Teresa
Adugna Kebede wrote:
to DuPont regarding their request. You mentioned that you are
What is the specific concern, I can include it in the letter for
Teresa,
I have reviewed the QUAL2E and QUAL2K modeling results from CH2M HILL. The QUAL2E model is the model
that was reviewed back in 2001 and 2002. They revised the model based on the comments given from EPA
and DWQ at the time. The technical memo includes the results from the QUAL2E model as well as the
QUAL2K model. They converted the QUAL2E model to the QUAL2K version and evaluated the relocation
scenarios. The analysis specifically addresses the effect the relocation of the DuPont plant from
downstream of Lock and Dam 3 to upstream of Lock and Dam 3 on predicted DO levels in the Cape Fear
River. The report also evaluates DuPont's nutrient data to determine whether the current loads comply
with DWQ's interim nutrient strategy for the Cape Fear River. I concur with their conclusion
concerning the impact of the relocation of the discharge on DO levels (Please refer to the January
19, 2007 Technical Memorandum entitled "Update of Cape Fear River Water Quality Model for Potential
Outfall Structure Relocation for DuPont by CH2M HILL). The only concern I have is that the QUAL2E
model was calibrated using input data from 1999. Please let me know if you want to discuss this
issue further or have any question concerning my review.
Thanks.
Adugna Kebede
1 of 1 11/28/2007 5:46 PM

Relocation NPDES # NC0003573
Subject: Relocation - NPDES # NC0003573
From: Adugna Kebede <[e-mail]>
Date: Fri, 09 Nov 2007 12:11:01 -0500
To: Teresa Rodriguez <[e-mail]>
Teresa,
I have reviewed the QUAL2E and QUAL2K modeling results from CH2M HILL. The QUAL2E model is the model that
was reviewed back in 2001 and 2002. They revised the model based on the comments given from EPA and DWQ at
the time. The technical memo includes the results from the QUAL2E model as well as the QUAL2K model. They
converted the QUAL2E model to the QUAL2K version and evaluated the relocation scenarios. The analysis
specifically addresses the effect the relocation of the DuPont plant from downstream of Lock and Dam 3 to
upstream of Lock and Dam 3 on predicted DO levels in the Cape Fear River. The report also evaluates DuPont's
nutrient data to determine whether the current loads comply with DWQ's interim nutrient strategy.for the
Cape Fear River. I concur with their conclusion concerning the impact of the relocation of the discharge on
DO levels (Please refer to the January 19, 2007 Technical Memorandum entitled "Update of Cape Fear River
Water Quality Model for Potential Outfall Structure Relocation for DuPont by CH2M HILL). The only concern I
have is that the QUAL2E model was calibrated using input data from 1999. Please let me know if you want to
discuss this issue further or have any question concerning my review.
Thanks.
Adugna Kebede
I of 1 11/19/2007 10:56 AM

DuPont Q6a12K
Subject: DuPont Qual2K
From: Teresa Rodriguez <[e-mail]>
Date: Fri, 02 Feb 2007 07:38:06 -0500
To: Adugna Kebede <[e-mail]>
CC: Gil Vinzani <[e-mail]>
Adugna,
The Eastern NPDES Unit received a request from DuPont Fayetteville Works to evaluate a model for the
relocation of the outfall in the Cape Fear River. A copy of the model was sent to the Modeling Unit. Please
let us know if you have any comments on this model.
Thanks,
Teresa
Teresa Rodriguez, P.E.
Division of Water Quality
EAST NPDES Program
919-733-5083 ext. 553
1 of 1 2/5/2007 8:04 AM

4W.
Mr. Gil Vinzani
NCDENR — Division of Water Quality
Surface Water Protection — NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
SUBJECT: Relocation of Final Effluent Discharge
NPDES Permit No. NC0003573
Dear Mr. Vinzani and Ms. Rodriguez:
DuPont Fluoroproducts
22828 NC Highway 87 W
Fayetteville, NC 28306-7332
January 23, 2007
Ms. Teresa Rodriguez
NCDENR — Division of Water Quality
Surface Water Protection — NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Enclosed is a copy of the final report from CH2M HILL of their modeling of the Cape
Fear River to determine what, if any, effect the relocation of the DuPont Company —
Fayetteville Works' final effluent discharge from the current position downstream of Lock
and Dam 3 to a new position upstream of the lock and dam would have on water quality.
Based on this modeling report, the relocation of the DuPont effluent discharge to
upstream of Lock and Dam 3 would have an insignificant effect on the Cape Fear River's
water quality.
As such, DuPont requests that the Division of Water Quality make a determination that
the relocation of the effluent discharge to upstream of Lock and Dam 3 would not result in any
change of this site's current NPDES permit limits.
Copies of this report have been sent to Mr. Chris Wu of the DWQ Modeling Unit and to
Ms. Belinda Henson in the Fayetteville Regional Office.
BACKGROUND
The effluent discharge from the DuPont site, which averages about 12 MGD, enters an
effluent channel that conveys the water approximately one mile to the Cape Fear River at a
point downstream of Lock and Dam 3. During the thirty-six years this site has operated, the
continuously flowing effluent has caused noticeable erosion the channel, which at times has
resulted in visible amounts of sediment discharging into the Cape Fear River.
E.I. du Pont de Nemours and Company

Mr. Gil Vinzani / Ms. Teresa Rodriguez
NCDENR — DWQ
January 23, 2007
Page 2 of 2
Before the start-up of the DuPont facility, the current effluent channel was a small natural
stormwater conveyance ditch that drained the area that is south of the DuPont manufacturing
operations. If the DuPont effluent is removed from this channel, then the channel would
revert back to its original function as a stormwater conveyance system what should have very
little if any water flow passing through it. It is believed that without the continuous flow of
the DuPont effluent, the channel would in time naturally vegetate and thereby eliminate all
future sediment discharge to the river.
PROPOSED SOLUTION
The proposed solution is to pipe the entire DuPont final effluent directly to the Cape Fear
River, which would allow the existing effluent channel to return to its original, natural state as
a stormwater ditch. To make this option cost effective, the pipe would be laid in a line that is
the shortest distance to the river, which would place the discharge of the effluent upstream of
Lock and Dam 3. Obvious benefits of this proposal are that there would be no routine
maintenance costs to DuPont, the pipeline would be less vulnerable to damage from flooding,
and the sediment to the river would be eliminated.
NPDES PERMIT CHANGE
If the proposed effluent discharge relocation should result in lower limits for this site's
NPDES permit, then the proposal would be much less attractive to DuPont, and alternative
solutions would have to be identified and evaluated.
However, the enclosed modeling demonstration indicates that the proposed effluent
relocation should not negatively impact water quality in the Cape Fear River. Therefore, it
seems appropriate that the NPDES permit limits would remain unchanged.
If you have any questions regarding this letter or if you need more details, please feel free
to call me at [phone]. If you have specific questions regarding the modeling report,
please contact Ms. Ruth Swanek of CH2M HILL at 919-875-4311 extension 16.
Enclosure

TECHNICAL MEMORANDUM CHS HILL
Update of Cape Fear River Water Quality Model for
Potential Outfall Structure Relocation for DuPont
' PREPARED FOR: E.I. du Pont de Nemours and Company (DuPont)
PREPARED BY: CH2M HILL j' J N Y �_ i l 1
DATE: January 19, 2007
' Executive Summary
This Technical Memorandum (TM) presents a discussion of the development and
application of a QUAL2E and QUAL2K model in the Cape Fear River from Buckhorn Dam
to Lock and Dam 1 near Kelly. The purpose of the modeling was to evaluate whether
DuPont can relocate its outfall structure from downstream of Lock and Dam 3 to upstream
of Lock and Dam 3 on the Cape Fear River near Fayetteville. The work was conducted for
DuPont for submittal to the Division of Water Quality (DWQ).
The modeling effort indicates that predicted dissolved oxygen is not sensitive to the location
of DuPont's outfall location. The modeling supports the conclusion that DuPont's NPDES
' permit limits for oxygen consuming wastes would not need to be reduced to protect water
quality in the Cape Fear River if the discharge point is moved upstream of the Lock and
Dam 3 structure.
iDuPont's effluent data also indicate that there are low nutrient concentrations in its effluent,
and its nutrient loads are well below those outlined in DWQ's interim nutrient loading
strategy. Moving the outfall upstream of Lock and Darn 3 should not negatively impact
' water quality.
' Introduction
The purpose of this TM is to evaluate whether DuPont can relocate its outfall structure from
' downstream of Lock and Dam 3 to upstream of Lock and Darn 3 on the Cape Fear River
near Fayetteville. DuPont's effluent channel is eroding, which results in sediment inputs to
the Cape Fear River. Communication with local citizens indicates that the effluent channel
was a small stormwater conveyance ditch prior to the DuPont facility's startup in 1970.
Because of the easily erodible soils in this region, the effluent channel is now approximately
forty to sixty feet wide and fifteen to twenty feet deep. In order to remove this sediment
load from the river and enhance water quality, DuPont would like to relocate its outfall to
upstream of Lock and Dam 3. Under this scenario, only stormwater from the forested area
outside DuPont's fence would enter the current effluent channel during rain events.
' DuPont has examined other alternatives including sediment basins at the bottom of the
channel, but has concerns about the ongoing maintenance that would be needed. This TM
evaluates whether DuPont's current NPDES permit limits would need to be reduced to
u

UPDATE OF CAPE FEAR RIVER WATER QUALITY MODEL FOR POTENTIAL OUTFALL STRUCTURE RELOCATION FOR DUPONT
protect water quality in the Cape Fear River if the discharge point is moved upstream of the '
Lock and Dam 3 structure.
The objectives of the modeling effort were to: '
• Evaluate whether DuPont can relocate its outfall structure from downstream of Lock
and Dam 3 to upstream of Lock and Dam 3 on the Cape Fear River near Fayetteville '
based on predicted water quality.
• Determine the predicted dissolved oxygen (DO) at DuPont's existing NPDES permit
limits at its current outfall location and at the proposed outfall location.
• Evaluate DuPont's nutrient data and determine whether current loads comply with the '
DWQ's interim nutrient strategy for the Cape Fear River.
Dissolved Oxygen I
Historical Modeling Information
The Cape Fear River was modeled by CH2M HILL in March 2002 and October 2001 using
QUAL2E from Buckhorn Dam to Lock and Dam 1 near Kelly. This model was an update of
two existing 1995 models developed by DWQ. These two models were combined and
recalibrated using in situ data collected by the Middle Cape Fear River Basin Association
(MCFRBA) during July 1999. Appendix A contains Technical Memorandum Number 3
"Cape Fear QUAL2E Model Development and Application" dated October 2, 2001 revised
March 5, 2002, which provides the details regarding the previous modeling efforts.
QUAL2E Model Update
CH2M HILL updated the existing QUAL2E model to reflect a change in the DuPont outfall
structure location. Lock and Dam 3 is represented in the model at reach 15, element 2. The
outfall structure was moved from reach 15, element 13 to reach 14, element 17 above Lock
and Dam 3 based on information provided by DuPont on the proposed outfall relocation
(Figure 1). Appendix B contains the output files for the relocation of the DuPont outfall
structure.
QUAL2E Model Results
Table 1 summarizes the predicted water quality with the DuPont outfall structure in its ,
current location at the current and proposed outfall locations as well as at each of the lock
and dam structures, the predicted dissolved oxygen sag points in the model. Table 2
represents the predicted conditions with the DuPont outfall structure relocated above Lock
and Dam 3. All model runs were performed using the Base Case scenario 1B outlined in the
prior modeling report (CH2M HILL, 2001 and Appendix A). Table 3 represents the change
in predicted water quality values at each river location due to the relocation of the DuPont '
outfall structure. The predicted changes in water quality due to the outfall relocation are
not significant. I
1

I
LI.
,I
pr iJ
TITLE: Figure 1
Site Layout Map
DuPont Fayetteville Works
Fayetteville, North Carolina
Map Projection: NC State Plane Feet, NAD 83
Aerial Photograph provided by DuPont, taken 12/2005
0 625 1,250
Feet
DRAWN: I OUPONT NO.:
ND 0=8105 4481
REVISION: FIGURENO.: URSD NO.:
D 1 18884515
FILENAME: 09FayetvlrJGis/Roject fi8uealPWnLSPPPoiV