NCG500622_Denial_20200618

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
To: Charles Weaver
NORTH CAROLINA
Environmental Quality
June 18, 2020
NPDES Compliance and Expedited Permitting
From: Hannah Headrick
Aquatic Toxicity Branch
Subject: Biocide Use Review
Purina Animal Nutrition, LLC
NPDES # NCG500622
Iredell County
Purina Animal Nutrition, LLC has requested approval of three chemicals: Nalco 1720,
NexGuard 22352, and Tri-ACT 1820. These products will be discharged from its Outfall 003
and into Third Creek.
Calculations predict the use of Nalco 1720, NexGuard 22352, and Tri-ACT 1820 products will
cause toxic impacts to aquatic life in the receiving water body, Third Creek. Therefore, the use
of these products as proposed at Purina Animal Nutrition, LLC is not approved.
We have been in direct contact and corresponded with consultants for Purina over months to
modify this proposal in ways that would allow for approval of these biocides. One option
explored adjusting dosage rates of each chemical. We had consultants explore the possibility of
demonstrating that the usage of the proposed biocides is directly related to water quality
parameters specified in the facility's NPDES Permit that would justify their usage at specified
dosage rates. Another suggestion was to find other chemicals and that would pass the model.
There are other options that Purina could explore. The facility could perform a Chronic multi -
concentration Ceriodaphnia 7-day reproduction test with these products. Purina could also have
a toxicity testing requirement added to its NPDES Permit. Another possibility is that because
discharge flow is historically low and it is doubtful the discharge reaches the stream, Purina
could explore an evaporative type non -discharge system to eliminate the need for a discharge
permit.
Please let us know if you have questions.
Cc: Jeffrey Madden - AARC Environmental
D E QJ� North Carolina Department of Environmental Quality I Division of Water Resources I Water Sciences Section
4401 and 4405 Reedy Creek Road 11621 Mail Service Center I Raleigh, North Carolina 27699-1621
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