71    BIOLOGICAL TREATMENT OF WASTEWATERS FROM
PRODUCTION OF TRIAZINE HERBICIDES
T.E. White, Chief Engineer
L. Lien, Staff Engineer
Corporate Environmental Technology
CIBA-GEIGY Corporation
Greensboro, North Carolina 27419
F.A. Hunter, Senior Process Engineer
St. Gabriel Plant
CIBA-GEIGY Corporation
St. Gabriel, Louisiana 70776
INTRODUCTION
CIBA-GEIGY manufactures a variety of s-triazine herbicides and specialty chemicals at its St.
Gabriel, Louisiana plant using carbon adsorption treatment (CAT) for management of dilute aqueous
wastes. As shown in Figure 1, the dilute wastestreams include triazine filtrate, multi-product facility
(MPF) discharge, and herbicide formulation and packaging flow. CAT effluent is combined with
stormwater and discharge from acid waste treatment before release. Aqueous wastes which are not
amenable to carbon adsorption are normally incinerated on-site. In December, 1990, St. Gabriel
received a new NPDES permit with a two year compliance schedule which limited biochemical oxygen
demand (BOD) discharge for the first time. The plant had previously agreed to a corporate challenge
to reduce annual discharge of ammonia-nitrogen by 65% using 1989's discharge as the base line.
In January, 1991, a plant-wide sampling program was initiated to identify major BOD and ammonia contributors, and to document the amount of BOD in the plant's effluent. The results indicated
that the plant discharged approximately 2,000 lb BOD per day; triazine filtrate was the major BOD
source. Effluent compounds identified with high potential for biodegradation were ureas, methy-
lethyl amine (MEA), and isopropyl amine (IPA).
Although other options such as source reduction were considered, biological treatment was selected
as the best alternative for reducing final effluent BOD. To support design of the full-scale facility,
S Triazine
Manufacturing,
and Packaging
Herbicide
Formulation     Multi-Product
Packaging Facility
CAT Feed
Equalization
Tar*
Stormwater
Runoll From
Units
"X
Waste
Triazine
Removal
Sequestrene Unit —
■ Cyanuric Chloride Unit
HCN Unit —
Wash Water
I  0 2MGD
Waste
Solid
Treatment
Carbon
Adsorption
Treatment (CAT)
Equalization
Tank
Acid Waste
Treatment
2 6 MGD
NPDES Discharge
Figure 1.   Flow schematic for St. Gabriel Plant dilute wastestreams.
48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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