NC0003719_Summary_20030728

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MONSANTO
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July 28,2003
Mr. Paul Rawls, Supervisor Division of Water Quality
North Carolina Department of Environment and Natural Resources
225 Green Street, Suite 714
Fayetteville, N.C. 28301-5043
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3468 Cedar Creek Road
Fayetteville, North Carolina 28301
Phone [phone]
Ref: Monsanto Company's NPDES Permit #NC0003719
Summary Report of Efforts Responding to May 2003 Toxicity Test Results
Dear Mr. Rawls:
Pursuant to your request, Monsanto Company is providing this summary report on our
efforts to address the excessive mortality we observed in the toxicity test performed on our May 21
whole effluent. The following lists the steps we have undertaken since obtaining these results:
• We have remained in contact with your office, making the appropriate reports and obtaining the
appropriate consents.
• We are working extensively with our two neighbors (DAK Americas and DuPont Teijin Films)
that send wastewater to our wastewater treatment plant (WWTP). Monsanto, DuPont, and DAK
each has its own team working on the issue. These teams meet weekly, if not more often, via
conference call to share information, analyze developments, and develop strategy.
• In addition to the in-house experts of Monsanto, DuPont, and DAK, we have also hired outside
expert consultants to analyze the existing data, identify data gaps, and develop strategy.
• In conjunction with DAK and DuPont, we have undertaken a Toxicity Identification Evaluation
(TIE) of our whole effluent that is responsible for the observed toxicity. The goal of the TIE is to
first identify the procedure that is effective at removing toxicity or affecting toxicity changes, to
then isolate fraction(s) that cause toxicity and finally to perform chemical identification on the
toxic fraction. The first phase of this process has been completed and the second phase is
ongoing. Results from the TIE will be used to design a toxicity reduction scheme.

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July 28, 2003 Page 2
• In conjunction with DAK and DuPont, we have tested the toxicity of the waste streams that feed
into the WWTP in an effort to identify the source of toxic constituent(s).
• In conjunction with DAK and DuPont, we are analyzing the operations that have sent
wastewater to the WWTP in the recent past as well as the current flows.
• In conjunction with DAK and DuPont, we are investigating the quality and activity of our sludge
both as it may have changed through time and as it compares to other similar operations.
• With your office's consent, we added an additional step to our wastewater treatment process.
On June 28, we began running our post -clarifier treated wastewater through a mobile activated
carbon filtration unit. With this unit online, the June toxicity test of whole effluent showed zero
mortality. Recognizing that the use of this system is an interim measure — and a very expensive
one at that - we intend to leave this system in place at least until the toxicity issue has been
resolved upstream, and we continue to work diligently to reach that resolution.
As this list makes clear, we are working very aggressively to resolve the toxicity issue at our
WWTP so that our whole effluent will pass the toxicity test, without the additional treatment by
activated carbon. If you have any questions about this matter, please contact me at (910)-433-
4205.
Sincerely,
Manhar N. Patel
Site Lead — Monsanto Fayetteville Plant
cc: Peter Virden — St. Louis
Molly Shaffer — St. Louis
Ruth Trotman — Fayetteville
Certified No. 7099 3220 0001 1361 5982