DEQ-CFW_00081874

OuPanl Awroprodum,
22028 NC Highway 87 W
�yenaualia, Nf, 2P> 6- W
IL
DuPont Fluoroproducts IV
April 23, 22
Mr. David Goodrich
NCDENR.— Division of Water Qjiality
Water Quality Section ---NP DES Unit
1617 Mail Service Center
Raleigh, NCB 27 9-161'7
SUBJECT`Changes in Discharges of Toxic Substances
NPDES Permit No, NI C000347
Dear Mr, Goodrich:
This letter requests that your office clarify a requirement found in Part [li of the,
subject North Carolina issued NPDE pen -nit.
`.C`he DuPont Cor pany —Fayetteville Works facility manufactures many fi.uorocarbon
coi pound& Each of these processes creates a wastewater that is ultimately Treated in and
discharged from the on -site wastewater treatment plant ( VTP),
s with all chemical processes, side reactions to the desired product reaction create
dozens or hundreds of byproducts in very leer concentrations. The fluorochernistry
involved in this processes is exceptionally complicated, and most of the byproducts are
unknown compounds, There is no standard method to identity these compounds, so a
research nnethodolo y utilizing -nuclear magnetic resonance (2 TN%) spectroscopy roust be
employed by an on -site DuPont chemist: to qualify and quantify an unknown fluorocarbon
compound,
DuPont is considering a research effort to identify and quantify some of tile unknown
fluorocarbon byprodrtc.ts in, the various. processes at the Fayetteville Works, facility,
Samples would be taker- from the wastewater discharge nearest to the process so as to
maximize the possibility of a detectable; concentration.
In. Part 11.I(C ) of the. subject NPDES permit, there is arequirement for the pennittee to
notify the Division of Water Quality "as soon as it knows or has reason to believe_ that
are. activity has occurred or will occur which would result in the discharge, on a routine or
frequent basis, of any toxic pollutant which is not limited in the per -it., if that discharge
will exceed_ one: hundred micrograms per liter (1_ 0 Agjl.)>'
The question to the Division is whether or not the subject permit requires, pursuant
to Part TIT(C'), reporting of compounds that are detectable only in the € ischarge of the
-manufacturing process, and that would not be detectable exiting; the site's W W`TP?
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DEQ-CFW 00081874

Mr. David Goodrich
April 23, 2002
Page 2 of 2
For example, assure a wastewater sample is taken from the discharge of a
manufacturing process and using NUPE spectroscopy, Compound A is detected at a
concentration of 20 nag/l..., The NMR detection limit for Compound.A is determined to be
I mg/L, meaning any concentration less than t mg/,lam carniot be detected nor quantified,
Assume that the process wastewater stream is added to the many gather wastewater
streams sent to the WWTP and that it represents 1% of the total WWTP influent.. This
stream would be diluted 100 times with the other wastewaters, so that the concentration
of Compound d .A. entering the WW'TP is now 0,2 mgtL (200 and cannot be detected
using the NMIR spectroscopy method.
In the above example, Compound A is entering the WWTP at a calculated
concentration of 200 ag,1L There is too literature available to indicate if Compound ,A is
degraded in an. activated sludge biological treatment system, if one assumes that little of
the material is biodegraded, then it follows that there is as much as 200 pg/L. of
Compound <A exiting the WWTP through the permitted Outfall 001, Per the requirement
of Part II(C ), if the discharge exceeds the 100 1iL "notification level", then the DiNdsion
of Water Quality would have to be notified. flo�kFever, analysis of Outfhl<l 001 shows no
detectable concentration of Compound A because the calculated concentration. of
0,2 mg/L is leas thanthe detection limit (t_ mg/L) of the only known analytical method for
detecting Compound A.
1_n the above example, would a permflee be, deemed to know or have: reason to
believe that a toxic substance is being discharged above the "notification level's and
therefore be required to notify the Division of Affater Quality of the discharge of
Compound zA pursuant to Part llI(C`.) of its NTDES permit`?
If you have any questions regarding this inquiry, or if you need more details, please
feel free to call me at (fit 10) 6 78-115 5 ,
Michael E. Johnson
Environmental Manager
cc. Mr. Paul. Rawls, NCDENR Division of Water Quality., Fayetteville
DEQ-CFW 00081875