NC0003719_Technical Assistance_20000817

Michael F. Easley, Governor
ATA
NCDENR
North Carolina Department of Environment and Natural Resources
August 17, 2000
Hope Walters, Environmental Operations Specialist
ORC, Wastewater Treatment Facility
Monsanto Company
P.O. Box 2307
Fayetteville, N. C. 28302
Subject: Technical Assistance
Monsanto Company
NC0003719
Cumberland County
Dear Mrs. Walters,
William G. Ross Jr., Secretary
Gregory J. Thorpe, Ph.D.
Acting Director
Division of Water Quality
Thank -you for meeting with Kitty Kramer and myself as we responded to your technical
assistance request. Your concern was over the sudden increase in ammonia nitrogen in the
wastewater treatment facility and the process was not responding to your. normal process control
corrections.
A tour of the treatment facility was given by yourself and your chief operator, Allen Baldwin.
We were told that several thousand gallons of ethylene glycol was discharged to -the facility the
previous week, which was a major concern of high organics. We were shown the sludge holding
tank, which is the sludge storage prior to land application, as being a.source of high ammonia
nitrogen. At this, time, the discharge from the holding tank back into the treatment system had
been stopped and was determined to be of minimal impact.
The process control records were then reviewed for abnormalities. It was noted that the sludge
age on the air basin had increased from an average of 40 days in February to 800 days currently.
This high sludge age is definitely not recommended for the activated sludge process.
Fayetteville Regional Office
225 Green Street— Suite 714, Fayetteville, North Carolina 28301-5043
Phone: [phone] FAX: [phone] Internet: ww.enr.state.nc.us/ENR
An Equal Opportunity 1 Affirmative Action Employer — 50% Recycled 110% Post Consumer Paper

Page 2
Monsanto
August 17, 2001
After considering all the facts, it is of my opinion that the process is not responding as you think
that it should because of the following reasons; the ethylene glycol is satisfying the biosolids's
organic food source needs and it will only continue to feed on the ammonia nitrogen after the
high organics are broken down. The slow pace at which this process is occurring is compounded
by the age of the sludge. I believe the process will indeedturn around with sufficient time, and
hopefully soon enough to meet your compliance needs.
I strongly suggest that as soon as the process will allow, that solids wasting be resumed in order
to return the sludge age back to a more reasonable number.
We appreciate the opportunity to be of assistance with your technical needs and share with you
the common goal of water quality excellence. If I can be of further assistance, I can be reached
at 910-486-1541 ext. 709.
Sinc;ely;
Don Register
Environmental Technician IV
Cc: Manhar Patel
FRO files
Operator Training and Certification, Tony Arnold