DEQp00021040

state,,of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
Alan W. Klimek, P.E., Director
December 20, 2002
Mr. Michael E. Johnson
Environmental Manager
DuPont Fluoroproducts
22828 NC Highway 87 W
Fayetteville, North Carolina 28306-7332
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NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
Subject: DMSO Waste Stream
Permit NC0003573
DuPont - Fayetteville Facility
Bladen County
Dear Mr. Johnson:
After consulting with our aquatic toxicology staff and staff from the Division of Waste Management .'s hazardous
waste program, the Division of Water Quality has reviewed and approved your request to discharge the DMSO waste
stream from the Nafion® Products manufacturing area to the wastewater treatment system with subsequent discharge
through outfall 001. It is the determination of this office that modification of the NPDES permit is not necessary as the
existing permit provides sufficient coverage and protection to accommodate the DMSO waste stream.
If you have any comments, questions, or concerns regarding this matter, please do not hesitate to contact me at
[phone], extension 508.
Sincerely,
Copy
Mark D. McIntire, P.E.
NPDES Permitting Unit
cc: Central Files
NPDES Unit
Fayetteville Regional Office
1617 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699-1617 -TELEPHONE [phone]/FAX [phone]
AN EQUAL OPPORTUNITY AFFIRMATIVE ACTION EMPLOYER — 50% RECYCLED/ 10% POST—CONSUMER PAPER
VISIT US ON THE WEB AT http://h2o.enr.state.nc.us/NPDES

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DuPont Fluoroproducts
Mr. Michael Templeton
NCDENR —Division of Water Quality
Point Source Branch
1617 Mail Service Center
Raleigh, NC 27699-1617
DuPont Fluoroproducts
22828 NC Highway 87 W
Fayetteville, NC 28306-7332
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SUBJECT: Addition of New Waste DMSO Stream to DuPont WWTP
NPDES Permit No. NC0003573
Dear Mr. Templeton:
27, 2002
This letter requests that the Division of Water Quality make a determination as to whether the
DuPont — Fayetteville Works can begin treating a new wastewater stream in its Wastewater
Treatment Plant (WWTP) without a modification of the subject NPDES Permit, or if such a
change would require a modification of said permit.
It is my belief that this insignificant change would not necessitate a permit modification. I hope
that after you read this letter you will agree with that conclusion.
WASTEWATER DESCRIPTION
The wastewater stream in question is the Waste DMSO that is generated in the Nafion® Products
manufacturing area. This waste stream is a RCRA hazardous waste due to its corrosivity
characteristic, meaning that it has a pH greater than 12.5 SU. The Waste DMSO is currently
shipped off-site to the DuPont Chambers Works facility in Deepwater, New Jersey, for disposal
in their NPDES permitted wastewater treatment plant.
The waste stream, which is estimated to average five (5) gallons per hour, would be a small
fraction of the WWTP influent flowrate of approximately one million gallons per day (1 MGD).
The composition of the wastewater stream is as follows:
Water
64%
Potassium hydroxide
25%
Dimethyl sulfoxide
8%
Potassium fluoride
3%
Methanol
Trace
Phenols
Trace
E. I. du Pont de Nemours and Company ® Printed on Recycled Paper
FL -4 Rev. 6/99

Mr. Michael Templeton
NCDENR —Division of Water Quality
August 27, 2002
Page 2 of 4
Dimethyl Sulfoxide (DMSO)
The major organic compound in this wastewater stream is dimethyl sulfoxide (DMSO) with a
CAS Number of 67-68-5. DMSO is a simple organic compound with the following structure:
X
CH3 — S — CH3
DMSO is a common compound, with is most familiar application being as a pharmaceutical
agent used for a variety of ailments, including pain, inflammation, scleroderma, interstitial
cystitis, and arthritis elevated intercranial pressure. It obviously has a very low mammalian
toxicity level, with an oral LD50 of 17,400 mg/kg body weight and a NOEL of 1,100 mg/kg/day
for rats. It has a dermal LD50 of 40,000 mg/kg body weight for rats.
DMSO has an extremely low aquatic toxicity. The LC50 (96 hrs.) for ten species of fish range
from 32,500 to 43,000 ppm. The LC50 for two species of protozoans are 32,000 and 38,000 ppm.
The concentration required to inhibit growth (EC50) for five species of blue-green algae and one
green algae species ranged from 0.4% to 4.0%. DMSO is non-bioaccumulating since the log of
the octanol/water partition coefficient is -1.35.
The existing Waste DMSO Storage Tank in the Nafion® manufacturing area will continue to be
used to store the Waste DMSO and will act as a large holdup tank. The waste stream is
generated batchwise, with as much as two months between the generation of batches. The
storage tank will allow this waste stream to be added slowly and consistently to the WWTP at an
anticipated rate to five (5) gallons per hour.
At the five gallon per hour rate, there would be approximately 80 lb/day of DMSO entering the
WWTP. At our usual influent flow rate of one MGD, the concentration of DMSO in the
influent would be 9.6 mg/L (9.6 ppm) as DMSO. We anticipate that after a brief acclimation
period for our bacteria, that the majority of the DMSO will be biologically degraded in the
WWTP. However, even if there were no degradation of the DMSO in the WWTP, the
concentration at the Outfall 002, with an average flowrate of approximately 12 MGD, would be
0.8 ppm, which is substantially less than the toxicity levels states above.
DMSO is not a regulated chemical in either federal or state regulations.
Potassium Hydroxide (KOH)
The potassium hydroxide (KOH) is listed as a hazardous substance with a reportable quantity of
1,000 pounds per day. There will be 250 pounds per day as KOH leaving the Nafion® process.
However, it will either be neutralized prior to introduction into the WWTP, or it will be
neutralized within the WWTP, with the result of the KOH being converted to potassium sulfate

Mr. Michael Templeton
NCDENR — Division of Water Quality
August 27, 2002
Page 3 of 4
and water. Potassium sulfate is not a regulated substance. There is an effluent limitation
guideline for the production of potassium sulfate, but the only two limited pollutants are TSS and
pH, which are already limited by the subject NPDES permit.
Potassium Fluoride (KF)
Potassium fluoride is not a regulated chemical in any federal or state regulation.
Methanol and Phenol
Both methanol and phenol are present in the Waste DMSO in trace quantities. The natural
commingling of the subject waste stream with other wastewaters in the WWTP will result in the
methanol and phenol being at non-detectable levels entering in the WWTP influent, and exiting
from Outfall 001 if they were to pass unaltered through the WWTP.
WASTE HISTORY
The Waste DMSO has been generated at this site for many years. When the Nafion® process
started up in 1980, an attempt was made to treat the Waste DMSO in the on-site WWTP. At that
time, the waste stream was sent batchwise from the Nafion® area, which resulted in
approximately 6,000 gallons of Waste DMSO entering the WWTP over a day period, followed
by two months of no addition of this waste. This cyclic pattern is not a good means of treating a
pollutant in an activated sludge WWTP.
Also at that time, the WWTP only had the current Equalization Basin as the aeration unit, using
floating surface aerators. This system unintentionally created areas with no aeration, in which
anaerobic bacteria existed that degraded the DMSO to hydrogen sulfide. When the surface
aerators would contact these dead areas, the hydrogen sulfide would be released to the
atmosphere resulting in unacceptable odors.
Because of this odor problem, the Waste DMSO was collected and then transported to the
DuPont — Chambers Works facility in Deepwater, New Jersey, where it was treated in their
larger, more efficient WWTP.
Per your request, the DuPont contact at the Chambers Works facility is Mr. Leo Karwaski.
Mr. Karwaski is the New Jersey licensed operator of the Chambers Works WWTP and can
answer any and all of your questions regarding their treatment of this waste stream. His direct
phone number is 856-540-2760.
Since the 1970 time period, the Fayetteville Works site's WWTP has been expanded and
improved, and the WWTP areas that harbored the anaerobic bacteria have been eliminated. The
DMSO should be easily biotreated aerobically without issue or concern.

Mr. Michael Templeton Page 4 of 4
NCDENR —Division of Water Quality
August 27, 2002
RATIONAL FOR THE CHANGE
In 2001, the DuPont - Fayetteville Works transported 232,000 pounds of the Waste DMSO by
highway to the DuPont facility in Deepwater, New Jersey, for disposal in that facility's WWTP.
The annual transportation cost to transport this waste 450 miles is approximately $10,800. In
addition, the waste is RCRA characteristically hazardous due to its corrosivity. Treating the
waste stream on-site is the best option from both a financial standpoint for DuPont and from a
highway safety standpoint.
SUMMARY
The Waste DMSO is successfully treated in an NPDES permitted activated sludge WWTP in
New Jersey. Over 200,000 pounds per year are shipped to the New Jersey facility, resulting in a
transportation cost of over $10,000 per year and the always possible transportation incident with
this characteristically hazardous waste.
The DuPont — Fayetteville Works wishes to begin treating this waste on-site in the activated
sludge wastewater treatment plant.
The Waste DMSO does not contain a regulated compound that would require a new permitted
parameter to the subject NPDES wastewater discharge permit. The appropriate parameters of
concern for this waste stream, specifically pH, BODS, and TSS, are already existing on the
current permit. DuPont is not seeking any increases to the existing permitted limitations as a
result of this new waste stream.
If you have any questions, please feel free to call me at [phone].
Environmental Manager
cc: Ms. Kitty Kramer, NCDENR — Division of Water Quality, FRO
Mr. Leo Karwaski, DuPont, Chambers Works

DuPont - Fayetteville Works: Addition of DMSO wastestream to on-site WWTP
Subject: DuPont - Fayetteville Works: Addition of DMSO wastestream to on-site WWTP
Date: Wed, 17 Jut 2002 16:20:36 -0400
From: "Michael E Johnson"<[e-mail]>
To: [e-mail]
Mike,
I heard your telephone message from this morning. Attached is a note I
sent to Charles Weaver on the same subject.
Let me know if this provides you all the needed information that you
requested.
Thanks for your help and guidance.
Mike
---------------------- Forwarded by Michael E Johnson/CL/DuPont on
07/17/2002 04:14 PM ---------------------------
Michael E Johnson
07/16/2002 03:50 PM
To: Charles.WeaverCncmail.net
cc: (bcc: Michael E Johnson/CL/DuPont)
Subject: DuPont - Fayetteville Works: Addition of DMSO wastestream to
on-site WWTP
Charles,
The DuPont - Fayetteville Works would like to begin introducing a new waste
stream to the influent to the on-site wastewater treatment plant (WWTP).
What, if anything, must DuPont do before it can begin treating the new
waste stream in the WWTP? As you will read below, there should be no
reason to modify the existing NPDES permit (No. NCO003573) as a result of
this minor change.
The waste stream is currently being sent off-site to a DuPont facility in
New Jersey where it is treated in that site's WWTP.
The new waste stream is the Waste DMSO' from the Nafion(R) manufacturing
process.
DMSO = dimethyl sulfoxide CH3 - SO - CH3 [CAS No. 67-68-51
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The existing Waste DMSO Storage Tank wilt continue to be used to store the
Waste DMSO and will act as a very large holdup tank. The waste stream is
generated batchwise, with sometimes a couple months between the generation
of the next batch. The storage tank wilt allow this waste stream to be
added slowly and consistently to the WWTP at an anticipated rate to five
(5) gallons per hour.
The composition of the waste stream is as follows:
Demin Water 64%
Potassium hydroxide 25%
Dimethyl sulfoxide 8%
Potassium fluoride 3%
1 of 2 7/30/2002 10:09 AM

DuPont - Fayetteville Works: Addition of DMSO wastestream to on-site WWTP
Methanol Trace
Phenols Trace
At the five gallon per hour rate, there would be approximately 80 lb/day of
DMSO entering the WWTP. At our usual influent flow rate of 1 MGD, the
concentration of DMSO in the influent would be 9.6 mg/L as DMSO. We
anticipate that after a brief acclimation period for our bacteria, that the
majority of the DMSO will be biologically degraded in the WWTP.
The potassium hydroxide (KOH) is listed as a hazardous substance with a
reportable quantity of 1,000 pounds per day. There will be 250 pounds per
day as KOH leaving the Nafion(R) process. However, it will neutralized
either prior to introduction into the WWTP, or it will be neutralized
within WWTP, with the result of the KOH being converted to potassium
sulfate and water. Potassium sulfate is not a regulated substance.
DMSO is not a regulated chemical in the federal regulations.
Potassium fluoride is not a regulated chemical in the federal regulations.
The natural commingling of the subject waste stream with other wastewaters
in the WWTP will result in the methanol and phenol being at non-detectable
levels if they were to pass unaltered through the WWTP.
I would appreciate it if you or another member of the NPDES Permitting
Section would let me know relatively quickly as to what is needed to begin
treating this new waste stream.
If you need more information, please feet free to call me at 910-678-1155.
Thank you for your help.
Michael E. Johnson
Environmental Manager
DuPont Company
Fayetteville Works
2 of 2 7/30/2002 10:09 AM

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This will be a common result of requiring nitrogen removal for these small
systems, if it can ever be accompltished at existing facilities with limited space.
Any previous planning or task force discussions that I have been a party to
regarding nitrogen removal for small systems involved possible limits of 12 mg/l as
in the Beachwood permit alternatives analysis requirement. Limits of 12 mg/l would
require removal facilities on most small plants whereas 6 mg/1 would require removal
on all plants.
The existing rule allocates 280,000 pounds of nitrogen to small dischargers
with a total of 2,800,000 pounds for all dischargers.
The proposed new rule allocates only 138,000 pounds to small dischargers with
a total of 3,000,000 pounds for all dischargers. Therefore, the total nitrogen
allocated increased by 200,000 -pounds (7%) and small discharges allocation decreased
by 142,000 pounds (51X).
If the 138,000 pounds allocated to small systems equates to 6 mg/1, then the
existing rule allocation of 280,000 pounds equates to slightly -over 12 mg/l.
It is significantly more economically reasonable-to.remove nitrogen on a large
scale where municipalities have treatment plants on -large tracts of land in remote
locations. .These facaities serve large customer bases and can.::easily spread the
cost of nitrogen removal facilities over the customer base without -a significant =
impact on the monthly bills. In addition, the large facilities can afford to have
employees present at the plant 24 hours per day to deal with potential methanol or
other problems. It is not economically feasible to install nitrogen removal on small
facilities or to provide 24 hour per day operation.
Nitrogen removal should not be required on these small facilities.
Heater and the Carolinas Chapter request the allocation to small dischargers
be changed to 345,000 pounds, which equates to approximately 15 mg/l as a
concentration.
Your favorable consideration will be greatly appreciated. If I can provide
clarification of any of these comments, please do not hesitate to contact me at 919-
467-8712, Ext. 37 or e-mail [e-mail].
Sincerely,
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