United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-091 July 1984
&ER& Project Summary
Testing and Evaluation of an
Alcohol Production Facility
Utilizing Potatoes as a Feedstock
William Kuby, Steve Nackord, and Walter Wyss
This study presents the sampling and
analysis results for the characterization
of the liquid effluents and solid residuals
from a process in which culled potatoes
are used as a feedstock for the produc-
tion of ethanol fuel. Gaseous emissions
were not studied. The facility, located in
eastern Idaho, produces approximately
1 million gallons of ethanol per year.
The effluents were sampled in Decem-
ber 1981.
Liquid and solid samples were taken
from sluice/flume water, chopper
product, makeup water, cooker product,
fermenter product, beer tank, stillage,
interim and final product, washwater,
fusel oil, acid bath and Sparkle* bath.
The effluents from the plant were
analyzed for ethanol and sugar content,
conventional parameters, metals, cya-
nide, phenols, nutrients, oil and grease,
priority pollutant organics and selected
pesticides. The effluents from this plant
in general showed the following signifi-
cant characteristics: oxygen demand
(TOC, COD, BOD), solids (TSS, TS,
specific conductance), nutrients (nitro-
gen and phosphorus) and metals (Al,
Cd, Ca, Cr, Fe, Mg. Mn, Hg, Ti, and Zn).
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Cincinnati, OH,
to announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use.
Introduction
The U.S. Environmental Protection
Agency (EPA) conducted a study of the
fuel alcohol industry to determine the
environmental impact of alcohol produc-
tion from grain and waste products. As
part of this study, the Industrial Environ-
mental Research Laboratory in Cincin-
nati, Ohio (lERL-Ci) and the Effluent
Guidelines Division (EGO) conducted
sampling and analyses to characterize
the air, water, and solid waste streams
from alcohol facilities and to obtain treat-
ability information.
Since many of the newer facilities
incorporate feedstocks such as sugar
beets, culled potatoes and fruit, and
sweet sorghum, rather than the grain and
waste products feedstocks analyzed in
the past, EPA has begun to evaluate the
environmental impacts of these nongrain
feedstock facilities. This report describes
the results of sampling and analyses of
the liquid effluents and solid residuals
from an ethanol facility utilizing one of
these feedstocks - potatoes. The full
report includes a description of the
process at the potato facility and the
environmental impact associated with
the effluents, presents the techniques
used to acquire the samples for analysis,
outlines the analytical techniques em-
ployed, and presents the results. An
appendix contains the quality assurance
and quality control (QA/QC) results.
Process Description
The alcohol productions facility converts
potatoes and grains into ethanol. During
the sampling period of December 2, 3,
-------
and 4, 1981, potatoes were used as the
feedstock. Figures 1 and 2 are flow
diagrams of the process.
Sampling and Analyses
The purpose of the sampling was to
characterize solid and liquid discharges
and potential discharge streams through-
out the process. Table 1 indicates the
analytical sample matrix and the following
paragraphs discuss the sampling points
and techniques used during the December
1981 sampling period.
Sluice/Flume Water Sample
The flume water was sampled at
sampling point 15 as potatoes were
transferred to the chopper tank. Four 1 -
liter grab samples were taken and
composited. The water was sampled
twice as it came off the conveyer belt and
twice from the agitated catch basin below
the conveyor. The flume water, which is
reused through three batches, was to be
discharged after the next batch.
Chopper Product
The chopped potatoes are transferred
as a batch to a cooker tank. The valve
located at the bottom of the batch tank,
sampling point 1, was used for sampling.
Makeup Water
The site used an onsite water well. The
tap located closest to the well pump (near
the batch tank) was sampled after
allowing the water to run for 10 minutes.
This is sampling point 2.
Cooker Product
Four 1-liter samples of the cooker
product were taken at sampling point 3,
one at the beginning, two in the middle,
and one near the end of the cycle.
Fermenter Product
The fermenter product was sampled at
the sampling port on the side of the
fermenter tank at sampling point 4. The
sample was composited as the batch was
being pumped to the beer tank. Two
composite fermenter product samples
were taken simultaneously. The first set
(4C) was maintained on ice during and
after sampling. The second set (4W) was
maintained at ambient temperatures for
36 hours in an attempt to approximate the
beer tank effluent. The samples are
referred as "cold" and "warm," respec-
tively, in this report. This sampling
protocol was necessary due to the
inaccessibility of the actual beer tank
effluent (beer still feed) stream. Chemical
analysis in the laboratory revealed few
differences between the "cold" and
"warm" fermenter product samples.
Beer Tank
The beer tank effluent sampling was
minimal due to difficulties in reaching the
effluent. Two 500-ml grab samples were
taken 16 hours apart at sampling point 5.
Stillage
The three stillage (beer still bottoms)
streams were sampled at sampling points
6 and 7. The excess stillage, or stillage
overflow, (material which the solid-liquid
separator [SOMAT] could not process)
was sampled by compositing hourly for
10 hours. The solid material or thick
stillage stream was sampled hourly for 10
hours at the SOMAT outlet. Also, one
grab sample of the thin stillage stream
was taken. This was sampled at the pipe
where the SOMAT discharged the liquid
to the main waste stream.
Well water 2
\ Optional i .,, , , ,_. ,22
' feedstock \ AIPha-3maylase (Diazyme) o"
! grain ' Gluco-amaylase (Taka-Therm)
A'"
YY
n.
I Caustic \
.t T . J
Caustic I Water \
mix
tank
Acid. Epsom
salt, lime
Cooker
discharge
pump
Drain
O Indicate sample collection points
Figure 1. Feedstock processing schematic.
2
-------
Beer feed
Steam
Thick O
stillage
Condenser
r Benzene ' '
storage f~^ I
Benzene pump \
»*ne batch cleaning by taking two 400-ml
grab samples three times during each
dump. The sample was taken at the drain
pipe sampling point 11. The three sets
were composited, sealed, and placed on
ice.
Fermenter Washout
The fermenter washout cycle for the
fermenter tank is identical to the cooker
washout cycle. The sampling and compo-
siting methods were the same as those
for the cooker washout sample. Samples
were taken at point 12.
Combined Washout
After delivery to the laboratory, the two
washout cycles were combined. Initially
performed a na lyses were repeated on the
combined sample with the exception of
the coliform analysis.
Fusel Oil
A grab sample of the accumulated fusel
oil was taken at sampling point 23 after
the material was mixed for approximately
8 hours. This sample was broken in
transit and was replaced with a sample
from a later process run; results, there-
fore, are only generic rather than test
specific.
Acid Bath
A 500-ml grab sample of the agitated
acid bath was taken at sampling point 24
sterilization cycle. The sample batch was
to be dumped the following day.
Sparkle Bath
A 500-ml grab sample of the agitated
Sparkle bath was taken at sampling point
25 during the sterilization cycle. The
sampled batch was dumped after a few
days.
Combined Bath
After delivery to the laboratory; the two
bath samples were combined. Subse-
quently, all initial analytical tests per-
formed on the bath solutions were
repeated on the combination sample.
Other Samples
Other samples were taken at various
points for possible analysis should the
mainstream analyses have shown poten-
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7a6/e 1. Analytical Sample Maxtrix
Parameter
tfl
*
ID No.
1
2
3
4C
4W
5i
5
5T
6
7
7G
8
9
11
12
13
15
23
24
25
27
30
Stream
Chopper product
Makeup water
Cooker product
Fermenter product (cold)
Fermenter product (warm)
1st beer tank effluent
2nd beer tank effluent
Beer tank tops
Excess stillage
Thick stillage
Thin stillage
Distillation product
200-proof dehydration
product
Washout cooker
Washout fermenter
Washout combination
Sluice water
Fusel oil
Acid bath
Sparkle bath
Bath combination
Field/lab blank
m
8
03
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
§
X
X
X
X
X
X
X
X
X
X
X
X
o
X
X
X
X
X
X
X
X
X
X
X
to
£5
X
X
X
X
X
X
X
X
X
X
X
Co
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
4
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
C S
H
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X X
X X
X
X
X
X
X X
S> £ 6 ^ *
* s 1 1 1
^ 5 "5 -c x
Q- O O O. Cj
X X X X X
X X X X X
X
X
X
X X X X X
^. >
O Q:
«j
-------
Table 2. General Chemical Analysis
Parameter
Method
BODs
COD
TOO
Total suspended solids
Total solids
Phenols (total)
Cyanides (total)
Ammonia
Nitrate
Sulfate
Phosphorus (total)
Specific conductance
Metals*
pH
Total Kjeldahl nitrogen
Oil and grease
Total and fecal coliform
Sugars, reducing
5-day incubation, sample analyzed for oxygen depletion
Acid dichromate reflux, back titrate with ferrous ammoni-
um sulfate
Conversion to COz, infrared quantitation
Gravimetric, W5°C, weigh residue on filters
Gravimetric, 105°C, weight of residue
Distill, aminoantipyrine color, CHCIs extraction
Distill, barbituric acid colorimetry
Distill, followed by nesslerization
Brucine colorimetric
Turbid/metric
Nitric/suHuric acid digest, ascorbic acid colorimetry
Wheatstone bridge conductivity
Atomic adsorption spectrophotometry following acid di-
gestion. Analysis by cold-vapor flame/ess AA (Hg), flame
and graphite furnace analyses as appropriate for others
Electrometric
SuHuric acid mercuric oxide digestion, distillation, ness-
lerization
Partition/gravimetric, freon extraction
Multiple tube fermentation (gas producers)
Condense with orthotoluidine in acetic acid followed by
spectrophotometry on liquid portion of samples
"Metals: At, Sb, As, Ba, Be, Bi, Ca. Cd, Cr. Cu. Fe. Pb, Mg, Mn, Hg, Ni, Se. Ag. Tl. Ti, and In.
on the relation of their acidity to the
buffering capacity of the receiving
environment. A pH drop of any magnitud ?
could result in aquatic population shifts
and destruction, corrosion of metallic
systems, and agricultural crop damage.
The results of the metals analyses
indicate that the wastes have significant
levels of several metals including alumi-
num, cadmium, calcium, chromium,
copper, iron, magnesium, manganese,
mercury, titanium and zinc. Without
further testing the source of metals
cannot be definitively isolated; however,
most can be attributed to the materials
added (e.g., Epsom salt) and to leaching
from the process equipment (primarily
stainless steel and aluminum). The levels
of these metals ranged from 180 to
67,000 //g/liter in the makeup water and
7 to 176,000 /ug/liter in the excess
stillage.
No priority pollutant organics were
detected in the samples. One unknown
sulfur compound was detected at 12/ug/L
Table3. Values for Conventional Parameters (mg/L, Unless Noted Otherwise)
Parameter
ID No.
1
2
3
4C
4W
Si
5
5T
6
7
7G
11
12
13
15
24
25
27
30
Stream
Chopper product
Makeup water
Cooker product
Fermenter product (cold)
Fermenter product (warm)
1st beer tank effluent
2nd beer tank effluent
Beer tank tops
Excess stillage
Thick stillage
Thin stillage
Washout cooker
Washout fermenter
Washout combination
Sluice water
Acid bath
Sparkle bath
Bath combination
Field/ lab blank
in
§
QQ
47,000
<2
107,000
102,000
102,000
59,000
54,000
20.0OO
25,000"
18,000
17,100
4,200
9,900
1.980
780
2,700
2,200
<2
a
o
0
160,000
<5
209.000
216.000
201.000
59.8OO
74,700"
54.800
22,000
7,500
4,600
<5
0
33,000
3.3
57,500
36,000
34,000
22.000
29,000"
21,000
7,700
1.600
1.9
I
a
o
<5
18.000
35,000
32,000
24,800
22,000
24,700
3,080
11,200
880
NA
CJ
o
§
o
o
76% wt
308
18% wt
6.3% wt
6.1% wt
5.8% wt
6.2% wt
10.7%wt
5.5% wt
8.1% wt
54,000
29.100
4,700
10,100
12,200
1,750
5,600
3,100
<10
©
Q)
I
V.
3: 1
Q^ Ql
5.50
7.39
4.97
4.88
4.88
4.58
4.78
5.16
4.74
4.65
4.67
551
2.76
4.45"
6.90
6.64
4.99s
6.14
4.46°
5.43"
4.63"
conductivit]
:m @ 25°C
.u \
C 24,000
460
>24,000
<2
|
a
1
<2
<20
9,200
20
270
<2
"Most of the BOD determinations were performed a second time to bring results in a qua/ifiable
range.
"Total solids method was 24 hr at 103°-J05°C.
cFirst pH determinations were performed on 12/5/81,
"Combinations were measured on 12/9/81.
'Rechecks were measured on 2/22/81.
Units are MPN/100ml (most probable no. per 100ml).
3mg/kg.
-------
in the flume water. With the exception of
alcohols, no compounds of significance
were detected in the samples, including
in the fusel oil.
Bacteriological quality is of concern
from the flume water and washout
waters. Coliform analyses are performed
as indicated tests for possible health-
related organisms such as fecal strepto-
coccus. More test ing would be required to
preclude bacterial sources other than the
feedstock itself.
Conclusions and
Recommendations
The preliminary results of this sampling
and analysis are consistent with those of
other fuel alcohol plants using a variety of
other feedstocks. Thus, the problems to
be addressed and methods of addressing
them may be similar.
The effluents from this plant contain
the following water quality variables and
pollutants that could degrade receiving
waters:
Oxygen demand (TOC, COD, BOD)
Solids (TSS, TS, specific conduc-
tance)
Nutrients (nitrogen and phosphorus)
Metals (Al, Cd, Ca, Cr, Cu, Fe, Mg,
Mn, Hg, Ti and Zn)
Bacteria (total and fecal coliform)
Corrosivity, low pH
Although primary concern for environ-
mental impacts should be with those
normal discharges from the process, one
must additionally be concerned with the
"dumping" of poor batches and the
disposal of the solid materials other than
by byproducts use (i.e., as a feedstock).
The low pH of the liquid stream
potentially has two effects:
adverse effect on crops if used in land
farming
corrosion of process equipment
It would appear that these streams
should be neutralized to a pH of 6 to 8 as
early as possible. Since the acidic level is
required for the fermentation process,
a realistic point for neutralization would
be downstream of the fermentation tank
in the beer tank. The chemical (a buffer
salt) used for neutralization at this point
must be benign with respect to the
byproduct use.
William Kuby, Steve Nackord. and Walter Wyss are with Acurex Corporation,
Mountain View. CA 94042.
Mary Ann Curran is the EPA Project Officer (see below}.
The complete report, entitled "Testing and Evaluation of an Alcohol Production
Facility Utilizing Potatoes as a Feedstock," (Order No. PB 84-187 962; Cost:
$ 10.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
-------
United States Center for Environmental Research
Environmental Protection Information
Agency Cincinnati OH 45268
Official Business
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