DESIGN AND OPERATION OF WASTEWATER PRETREATMENT
FACILITIES FOR TWO CORN WET MILLS
Leo A. Ebel, Jr., Project Engineer
Consoer, Townsend & Associates Ltd.
St. Louis, Missouri 63109
Mahlon Kaloupek, Director of Quality Control
Corn Sweeteners, Inc.
Archer-Daniels-Midland Co.
Decatur, Illinois 62525
Glen Kimball, Project Engineer
Corn Sweeteners, Inc.
Archer-Daniels-Midland Co.
Cedar Rapids, Iowa 52401
INTRODUCTION
For many years a sweetener known as dextrose has been available. Dextrose is produced
by the refining of corn or other starch products. Although not as "sweet" as sucrose refined
from sugar cane or sugar beets, dextrose has competed with sugar with limited success in the
commercial sweetener market. A recent technological advance made it possible to create a
new product that was much sweeter than dextrose and even sweeter than sucrose. This
sweetener is produced through a rearrangement of atoms within the basic dextrose molecule
which creates an isomer of dextrose called fructose.
Various corn wet milling operations experimented with the large-scale production of high
fructose corn syrup (HFCS) but were unable to make any significant inroads on sucrose in
the sweetener market. However, early in 1975 when various factors combined to produce
shortages of and a sharp increase in the price of sugar, the fructose manufacturers found the
competitive situation to be much more favorable. Fructose was successfully marketed as a
product that was less expensive, sweeter and produced from a raw material much more stable
and available than sugar. Fructose quickly captured nearly a quarter of the approximately
12 billion-lb sweetener market in this country.
Existing manufacturers struggled to increase their capacity, while several organizations
rapidly developed plans to construct new fructose production facilities. Consequently, just
as this industry was desperately hurrying to grow, it was faced with significant problems
created by stricter limitations on its wastewater discharges. In addition to the stringent controls on direct discharges to receiving streams imposed by the Effluent Limitations Guidelines, even the plants that had been relying on their municipal waste treatment facilities to
accommodate their relatively uncontrolled discharges, were faced with the prospect of
limiting their quantities.
The Corn Sweeteners, Inc., Division of the Archer-Daniels-Midland Co. (ADM) was particularly affected by the implications of increased wastewater discharges that would be caused
by the planned large scale expansions of their production facilities in Decatur, Illinois and
Cedar Rapids, Iowa. Both plants were discharging to municipal sewer systems and both were
already under orders to reduce the loads that were being discharged, due to the adverse
affects that were resulting in the performance of the municipal treatment systems. ADM
turned to CT&A Ltd, to assist them in managing their wastewater situation such that the
new constraints would not interfere with their planned production expansions.
It was quickly apparent that extensive, rather effective pretreatment facilities would be
required at both locations-Cedar Rapids, Iowa (hereinafter referred to as Facility A) and
Decatur, Illinois (Facility B)—to reduce the contamination of the wastewater discharges
from the production facilities to a level that would be acceptable for discharge to the municipal treatment systems.
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