United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/002 April 1995
&EPA ENVIRONMENTAL
RESEARCH BRIEF
Waste Minimization Assessment for a Bourbon Distillery
Marvin Fleischman*, Michael Parris*,
Eric W. Daley**, and Gwen P. Looby
Abstract
The U.S. Environmental Protection Agency (EPA) has funded
a pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the expertise to do so. Waste Minimization Assessment Cen-
ters (WMACs) were established at selected universities and
procedures were adapted from the EPA Waste Minimization
Opportunity Assessment Manual(EPA/625/7-88/003, July 1988).
That document has been superseded by the Facility Pollution
Prevention Guide (EPA/600/R-92/088, May 1992). The WMAC
team at the University of Louisville performed an assessment
at a plant that manufactures bourbon whiskey and distiller
dried grains as a byproduct from corn, rye, and malt. The
grains are milled, mixed together, and cooked. Then the result-
ing mixture is allowed to ferment. After fermentation, the mix-
ture is processed in a distillation column. The distillate is
diluted to proper proof and placed in charred barrels for aging.
After an appropriate storage period, the barrels are emptied
and the contents are shipped in tank trailers. The team's
report, detailing findings and recommendations, indicated that
large quantities of CO2 and ethanol are vented from the plant
and that significant cost savings could be achieved through
CO2 and ethanol recovery.
This Research Brief was developed by the principal investiga-
tors and EPA's Risk Reduction Engineering Laboratory, Cincin-
nati, OH, to announce key findings of an ongoing research
project that is fully documented in a separate report of the
same title available from University City Science Center.
* University of Louisville, Department of Chemical Engineering
"University City Science Center, Philadelphia, PA
Introduction
The amount of waste generated by industrial plants has be-
come an increasingly costly problem for manufacturers and an
additional stress on the environment. One solution to the
problem of waste generation is to reduce or eliminate the
waste at its source.
University City Science Center (Philadelphia, PA) has begun a
pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the in-house expertise to do so. Under agreement with EPA's
Risk Reduction Engineering Laboratory, the Science Center
has established three WMACs. This assessment was done by
engineering faculty and students at the University of Louisville's
WMAC. The assessment teams have considerable direct ex-
perience with process operations in manufacturing plants
and also have the knowledge and skills needed to minimize
waste generation.
The waste minimization assessments are done for small and
medium-size manufacturers at no out-of-pocket cost to the
client. To qualify for the assessment, each client must fall
within Standard Industrial Classification Code 20-39, have gross
annual sales not exceeding $75 million, employ no more than
500 persons, and lack in-house expertise in waste minimiza-
tion.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers and re-
duction of waste treatment and disposal costs for participating
plants. In addition, the project provides valuable experience for
graduate and undergraduate students who participate in the
program, and a cleaner environment without more regulations
and higher costs for manufacturers.
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Methodology of Assessments
The waste minimization assessments require several site visits
to each client served. In general, the WMACs follow the proce-
dures outlined in the EPA Waste Minimization Opportunity
Assessment Manual (EPA/625/7-88/003, July 1988). The WMAC
staff locate the sources of waste in the plant and identify the
current disposal or treatment methods and their associated
costs. They then identify and analyze a variety of ways to
reduce or eliminate the waste. Specific measures to achieve
that goal are recommended and the essential supporting tech-
nological and economic information is developed. Finally, a
confidential report that details the WMAC's findings and recom-
mendations (including cost savings, implementation costs, and
payback times) is prepared for each client.
Plant Background
The plant produces bourbon whiskey and distiller dried grains
from corn, rye, and malt. It operates three shifts/day to produce
approximately 5 million gal of bourbon and over 16,000 tons of
distiller dried grain/yr.
Manufacturing Process
The basic raw materials—corn, rye, and malt—are milled in
hammer mills and fed to cookers. Water and setback (thin
stillage from the drying of spent grain after the alcohol and
large solids have been removed) are added and the resulting
mixture is cooked. During cooking, the starch in the corn and
rye is converted to sugar. After the conversion has taken place,
the mixture (known as mash) is pumped to a fermenter where
yeast is added to complete the conversion of sugar to alcohol.
Upon completion of the fermentation cycle, the mash (or beer)
is pumped to an intermediate tank called the beer well.
The contents of the beer well are pumped to the distillation
column where the alcohol is steam stripped from the beer. The
steam stripper distillate is condensed and pumped to the dou-
bler for final distillation. Distillate from the doubler is condensed
and pumped to the barrel-filling operations; spent grain is
pumped to the dry house for processing.
At the barrel-filling facility, the distillate is diluted to proper
proof with demineralized water. Barrels (of charred new white
oak) are filled with the diluted distillate and transported to the
warehouse for aging.
During the storage period (a minimum of four years), the
material in the barrel goes through a maturation or aging
process by which the distillate is transformed into a bourbon.
When the product in the barrel is determined to be of proper
quality, the barrel is transported to the dumping area. There
the contents of the barrel are poured through steel screens for
removal of solids. The product is then pumped to one of two
storage tanks from which it is loaded into tank trailers for
shipment.
Spent grain from the distillation operations is processed into
distiller dried grain (an animal feed additive) in the dry house.
The spent grain is processed in centrifuges where the solids
are concentrated and the excess water (centrate) is removed.
The concentrated solids are fed to an air dryer and the centrate
is pumped to an evaporator where the dissolved solids are
concentrated. The viscous discharge (syrup) from the evapora-
tor is mixed with a portion of the dried grain stream as it is
recycled back to the dryer. The portion of the dried grain
stream not used as recycle is conveyed to one of two storage
silos if the moisture content is satisfactory.
An abbreviated process flow diagram for this plant is shown in
Figure 1.
Waste Management Opportunities
The type of waste currently generated by the plant, the source
of the waste, the waste management method, the quantity of
the waste, and the annual waste management cost for each
waste stream identified are given in Table 1.
Table 2 shows the opportunities for waste minimization that the
WMAC team recommended for the plant. The minimization
opportunity, the type of waste, the possible waste reduction
and associated savings, and the implementation cost along
with the payback time are given in the table. The quantities of
waste currently generated by the plant and possible waste
reduction depend on the production level of the plant. All
values should be considered in that context.
It should be noted that the economic savings of the minimiza-
tion opportunity, in most cases, results from the need for less
raw material and from reduced present and future costs asso-
ciated with waste treatment and disposal. Other savings not
quantifiable by this study include a wide variety of possible
future costs related to changing emissions standards, liability,
and employee health. It also should be noted that the savings
given for each opportunity reflect the savings achievable when
implementing each waste minimization opportunity indepen-
dently and do not reflect duplication of savings that would
result when the opportunities are implemented in a package.
Additional Recommendations
In addition to the opportunities recommended and analyzed by
the WMAC team, several additional measures were consid-
ered. These measures were not completely analyzed because
of insufficient data, minimal savings, implementation difficulty,
or a projected lengthy payback. Since one or more of these
approaches to waste reduction may, however, increase in
attractiveness with changing conditions in the plant, they were
brought to the plant's attention for future consideration.
• Seal the grain leaks found throughout the conveying opera-
tions.
• Install a shutoff mechanism that provides a tighter seal atthe
discharge of the milled grain hoppers in orderto reduce grain
losses.
• Control ethanol emissions from storage tanks.
This research brief summarizes a part of the work done under
Cooperative Agreement No. CR-814903 by the University City
Science Center under the sponsorship of the U.S. Environmen-
tal Protection Agency. The EPA Project Officer was Emma
Lou George.
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Corn,
rye,
malt
Distiller dried
grains shipped
Bourbon
shipped
Figure 1. Abbreviated process flow diagram for bourbon whiskey production.
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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/S-95/002
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