HomeMy WebLinkAbout201706201041Mercury Emissions to Cape Fear River
Subject: Mercury Emissions to Cape Fear River
Date: Tue, 3 Jul 2001 12:17:26 -0400
From: "Michael E Johnson" <Michael. E.JohnsonC�USA.dupont.com>
To: Mike.TempletonC�ncmail.net
CC: Kitty. KramerC�ncmail.net
Mike,
Here is an Email detailing the question I have for you regarding the
discharge of mercury in the wastewater stream from the DuPont -
Fayetteville Works (NPDES Permit NC0003573) to the Cape Fear River.
I am sending you this message since you have been assigned the task of
renewing our NPDES Permit.
BACKGROUND:
This site using potassium hydroxide (KOH) in several applications within
the DuPont(TM) Nafiion(R) manufacturing process. Potassium hydroxide
apparently contains trace levels of mercury. It was recently discovered
that our KOH supplier (OxyChem) has not and cannot meet the contractual
terms that the KOH have no detectable levels of mercury. OxyChem has
assured DuPont that they can meet a mercury specification of "less than
0.02 mg/L Hg" in their KOH. 20 µq (L
DuPont consumes 35,000 lb/day of KOH, which is neutralized and discharged
through Outfall 001 and ultimately through Outfall 002. If the mercury
concentration in the KOH is 0.02 mg/L, then the average mass discharge
would be 0.0007 lb/day Hg.
Outfall 001 averages about 1.0 MGD and in 2000 had a one day low flow of
0.426 MGD. Outfall 002 averages about 14.5 MGD and in 2000 had a one day
low flow of 4.981 MGD.
At the average flow rate of 1.0 MGD, the average Outfall 001 concentration
of mercury (0.0007 lb/day Hg) would be 0.084 ug/L Hg.
At the low flow rate of 0.426 MGD, the Outfall 001 concentration of mercury
(0.0007 lb/day Hg) would have been 0.197 ug/L Hg.
At the average flow rate of 14.5 MGD, the average Outfall 002 concentration
of mercury (0.0007 lb/day Hg) would be 0.006 ug/L Hg.
At the low flow rate of 4.981 MGD, the Outfall 002 concentration of mercury
(0.0007 lb/day Hg) would have been 0.017 ug/L Hg.
Per Kitty Kramer, DWQ requires a minimum detection levet (MDL) of 0.2 ug/L
for mercury.
The one day low flow rate for Outfall 001 with the average mercury
discharge would have resulted in a mercury concentration just under the
MDL, however if the site were discharging this unusually low flow rate at
Outfall 001, then the production areas would not be operating normally, and
the mass discharge of mercury would be correspondingly lower.
All of the other above flow scenarios result in mercury concentrations well
below the State's MDL for mercury.
QUESTION:
What, if anything, does the DuPont -Fayetteville Works need to do to
address the discharge of this wastewater that contains mercury at what
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Mercury Emissions to Cape Fear River
should be non-detectable levels?
If you wish to contact me by telephone, my number is 910-678-1155.
Thanks for your assistance on this issue.
Regards,
Mike Johnson
Environmental Manager
DuPont -Fayetteville Works
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