v>EPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 2771 1
Research and Development
EPA-600/S2-81-038 July 1981
Project Summary
Level 1 Environmental
Assessment of Electric
Submerged-Arc Furnaces
Producing Ferroalloys
C. W. Westbrook and D P Daugherty
An EPA/IERL-RTP Level 1 multi-
media environmental assessment of
the ferroalloy industry was conducted.
The report contains general industry
statistics and the results of sampling
and analysis at three plants (six furnaces
total).
The industry is facing severe pressure
from imported products and its con-
tinued viability is uncertain. In addition,
this report indicates that the potential
for serious environmental problems
exists within some segments of the
industry but does not prove that the
pollution problems are occurring.
Specifically, the pollution potential of
covered (mix-sealed and sealed) fur-
naces is substantially higher than for
open type furnaces, primarily due to
the high concentration of organics in
gases generated by covered furnaces.
The covered furnaces are estimated to
generate polycyclic organic material
(POM) at the rate of about 1,230 to
11,080 kg/yr (2,710 to 24,430 Ib/yr)
per megawatt of furnace capacity or
208.800 to 1,878,800 kg/yr (460,300
to 4,120,000 Ib/yr) for all U.S. furnaces
of this type. Open furnace POM gen-
eration rate is estimated to be 100 to
900 kg/yr (220 to 1,980 Ib/yr) per
megawatt of furnace capacity or
134,500 to 1,210,500 kg/yr (296,500
to 2,668,700 Ib/yr) for all U.S. fur-
naces of this type. Covered furnaces
comprise only 14 percent of the indus-
try's production capacity and no
growth in their use is expected. These
estimated nationwide POM genera-
tion rates (estimated rates before the
emission control devices) are in the
same order of magnitude as estimated
POM generation rates (before control
devices) of slot type coke ovens,
which EPA considers to be a major
emitter. However, the control devices,
which are in use on all U.S. ferroalloy
furnaces, remove most of this material
from the gas stream. Samples from
one mix-sealed furnace were analyzed
by GC/MS which gave positive identi-
fication of known organic carcinogens
in both the clean gas discharged by the
scrubber (but before passing through
the flare which is expected to destroy
some organics) and in the water dis-
charged by the scrubber (which is
treated before discharge from the
plant). Low resolution mass spectro-
graphic (LRMS) analysis indicates the
presence of carcinogens in the cleaned
scrubber discharged gas (before flar-
ing) or four of the five scrubber equipped
furnaces tested, and the water dis-
charged from all scrubbers tested
(before wastewater treatment), and in
the gases generated by one open
furnace served by a baghouse (emis-
sions from the baghouse were not
determined). LRMS indicated the
presence of carcinogens in the waste-
water discharged by only one (no
longer operating) of the three plants
tested.
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The report indicates areas in which
further study and/or emissions.quan-
tification is needed.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory. Research Tri-
angle Park, NC, 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).
Introduction
Ferroalloys are alloying elements
which when added to molten iron or
steel impart specific characteristics,
such as hardness, ductility, and corrosion
resistance, to the finished product. The
United States is one of the world's
largest producers and consumers of
ferroalloys. Annual U.S. production is
about 1.45 million tonnes and con-
sumption is about 2.1 million tonnes.
Ferroalloys are manufactured primarily
in submerged arc electric furnaces.
Other production and refining methods
are vacuum and induction furnaces,
exothermic (alummo-silico-thermic)
processes and electrolytic manufacture
of high purity metals.
The submerged arc furnace, Figure 1,
consists of a refractory lined crucible
with a tap hole near the hearth level to
withdraw the molten product Power is
supplied to the furnace through carbon
electrodes which extend downward
through the charge material to a point
slightly above the hearth. Charge mate-
rials, which include ores, scrap iron,
gravel, coal, coke, and sometimes
woodchips, are fed to the furnace as
required to keep the crucible filled. The
electric current passing into the furnace
raises the temperature of the charge
into the range that the reduction re-
actions (basically removal of oxygen
from the metals) can occur. Large
volumes of carbon monoxide gas are
produced in the reduction reactions.
Furnace power consumption rates range
from about 7 megawatts to over 50
megawatts depending on furnace size
and product being made.
Furnaces are categorized by the type
of furnace top cover used There are two
basic categories (open and covered) and
two subtypes for each basic category
The open category is composed of totally
open furnaces in which there is an open
gap of one meter or more between the
crucible top and the fume collecting
hood, and close hooded in which this
gap is significa ntly reduced by removable
doors or panels that reduce the amount
$yU«&»!VJc&1'*§
Molten Ferroalloy
Carbon Hearth
i i i i i i i i i i i i T
Refractory
Lining
Shell
Crucible
Tap Hole
l^w,^. ;*;«^«*,r.^,^| i
/.ad/e
Figure 1. Submerged-arc furnace for ferroalloy production
2
of air drawn into the hood system. Them
covered category includes the mix-
sealed furnaces in which a tight-fitting
cover is installed on the crucible and is
partially sealed by raw materials mounded
over the openings in the cover through
which the electrodes pass, and sealed
furnaces which are similar to the mix-
sealed furnace except mechanical seals
are used around the electrodes. Two
emission control systems are used with
covered furnaces, one system to with-
draw gases from beneath the cover
(primary control system) and a hood
system above the cover to collect fumes
escaping the cover (secondary control
system).
New Source Performance Standards
(NSPS) for emission to the atmosphere
from ferroalloy manufacture were based
on best available control technology for
the open type furnaces. EPA data col-
lected in support of these standards
showed that a particulate emission
standard based on sealed furnace tech-
nology would have resulted in even
lower particulate emissions. This stan-
dard was not adopted because of an
objection that such a standard could
seriously affect the industry's ability to
respond to rapidly changing markets
conditions by restricting their ability to*
manufacture different products in the
same furnace.
EPA did, however, decide to further
investigate the subject of product flexi-
bility recognizing that solution of this
problem could ultimately lead to stan-
dards of performance based on sealed
furnace technology This task was
assigned to EPA's Industrial Environ-
mental Research Laboratory (IERL) in
Research Triangle Park, N. C. As a first
step, IERL. analyzed some of the samples
previously obtained and found indica-
tions that sealed furnaces generated
substantially more organics, including
polynuclear aromatics (PNA), than did
open furnaces. To verify this finding,
gases generated by one sealed furnace,
which was alternatively producing
silicomanganese and ferromanganese,
were sampled and analyzed. That study,
which experienced some sampling
difficulties, did indicate that a signifi-
cant concentration of PNAs exist in the
gases generated by the furnace and that
high energy venturi scrubbers might be
effective in their capture.
Since these test results suggested
that a standard of performance based on
sealed furnaces might result in decreased
environmental protection, a decision.
was made to more fully characterize
-------
ollutants generated by and emitted
'from ferroalloy furnaces. The present
study is the first phase of this effort. A
complete multimedia environmental
assessment of the industry was desired;
however, funding limitations prevented
such a comprehensive study. The study
design which resulted from considera-
tion of funding limitations, and the need
to explore the pollutant generation
potential of several ferroalloy furnaces,
particularly the mix-sealed type, do not
include furnace types and mode of
pollution control (i.e., baghouse or
scrubber) in the same proportions as
they exist in the industry. The design is
believed, however, to accomplish the
next logical step in the assessment and
to represent the best approach for the
available funds.
The primary objective of this study is
to determine if there is a significant
difference in the types and amounts of
organic pollutants generated by open
and mix-sealed furnaces. To accomplish
this objective detailed testing, by EPA/
IERL-RTP Level 1 procedures, was done
at three plants. Level 1 is designed to
determine a wide variety of inorganic
and organic species each to within at
least 1 /3 to 3 times the actual concen-
tration in the stream sampled. Some of
the information obtained, however, is
better than the overall accuracy. Partic-
ulate concentrations in the gas streams,
which are sampled at a single point,
should be within 1/2 to 2 times actual
values. Accuracy for gaseous compo-
nents is not affected by the velocity
profile. Thus, total organics, which are
determined by extracting the samples
and weighing the residue in the extract,
should be within 1/2 to 2 times actual
stream concentrations. The final steps,
fractionation of the extracts by liquid
chromatography and quantitation by
infrared and mass spectrographic anal-
ysis, reduce the accuracy for determining
an individual compound category to
within 1/3 to 3 times the actual concen-
tration in the stream sampled.
Both open and mix-sealed furnaces
were tested and products included
ferromanganese, 50 percent ferrosilicon,
and 75 percent ferrosilicon. The study
design does not allow a complete eluci-
dation of the separate effects of furnace
type and product manufactured. Also,
since the gas from mix-sealed furnaces
is flared, the actual organic emission to
the atmosphere generally cannot be
determined.
FT wo furnaces at each of three plants
ere tested. Scrubbers were used on
five of the furnaces and samples were
taken of scrubber waters and of the
scrubbed gas before it was flared. The
one furnace tested which was served by
a baghouse was sampled before the
pollution control devices. Samples were
also taken of the plant discharge waste-
waters.
Results and Conclusions
Summarized in Table 1 are the partic-
ulate generation rates by the furnaces
(before emission control). The data are
only for particutate going to the primary
emission control systems. Thus, tapping
and product handling are not included.
With the exception of furnace A-1,
there does not seem to be a significant
difference in particulate generation
rates from variations in product type or
type of furnace used when compared on
a kg/MW-hr basis. Furnace A-1 seemed
to be generating more secondary fume
(based on visual estimates) than typical
mix-sealed furnaces which may account
for the low value obtained. When com-
pared on a kg/Mg of alloy produced
basis, it appears that particulate genera-
tion rates increase in the order of FeMn,
50 percent FeSi, and 75 percent FeSi.
The data are not conclusive for different
types of furnaces since particulate
generation rates of furnaces B-1 and B-
2 are comparable but less than for
furnace C-2, all 50 percent FeSi product.
The difference may be due to lower
efficiency (kW-hr/kg product) in furnace
C-2.
Summarized in Table 2 are the organic
generation rate data (equivalent to Table
1 for particulates). In this case, signifi-
cant differences are noted when the
generation rates are compared on either
a kg/MW-hr or kg/Mg basis. The open
furnaces obviously have lower overall
organic generation rates than the mix-
sealed furnaces in which limited com-
bustion was occurring. It is interesting
to note the variation in organic genera-
tion rates by the different mix-sealed
furnaces. Although the same product
was being made in furnaces B-2 and C-
2, the organic generation rates differ by
almost a factor of 3 (a wider variation
than expected for determination of total
organics by Level 1 procedures). This is
probably due to more combustion under
the cover of furnace C-2 (indicated by
the Orsat analyses of the furnace gases).
Most interesting are the results for
furnace A-1 which had almost complete
undercover combustion. The trend
observed for the mix-sealed and open
furnaces strongly indicates that more
complete destruction of organics would
occur in sealed or mix-sealed furnaces
in which complete undercover combus-
tion was occurring.
The efficiencies of the scrubbers for
removal of particulate and organic
matter from the gases generated by the
furnaces are given in Table 3. Although
all scrubbers have particulate capture
efficiencies of over 90 percent, a signifi-
cant difference in capture efficiency for
organics is observed. As expected, the
capture efficiency increased with an
increase in either pollutant inlet con-
centration or scrubber pressure drop.
Furnace Type
A-1
A -2
B-1
B-2
C-J
C-2
Mix-sealed
Open
Open
Mix-sealed
Mix-sealed
Mix-sealed
Operating
Product Power, MW kg/hr
FeMn
FeMn
50% FeSi
50% FeSi
75% FeSi
50% FeSi
11.4
15.8
48.4
48.0
15.5
16.8
47.3
174.9
470.6
447.7
196.7
187.9
kg/MW-hr
4.1
11.1
9.7
9.3
12.7
11.2
kg/Mg
alloy
10.1
26.0
49.2
46.0
103.0
68.9
Table 2. Summary of Furnace Organic Generation Data-
Furnace Type
A-1
A-2
B-1
B-2
C-1
C-2
Mix-sealed
Open
Open
Mix-sealed
Mix-sealed
Mix-sealed
Operating
Product Power, MW
FeMn
FeMn
50% FeSi
50% FeSi
75% FeSi
50% FeSi
11.4
15.8
48.4
48.0
15.5
16.8
kg/Mg
kg/hr kg/MW-hr alloy
0.72
5.5
12.0
76.7
19.6
9.9
0.06
0.35
0.25
1.60
1.27
0.59
0.15
0.82
1.25
7.89
10.27
3.65
-------
The concentrations of particulates
and organics in the plant discharge
wastewaters are given in Table 4. These
effluents do not contain cooling or
sanitary water.
All samples collected during the test
were extracted with methylene chloride
and analyzed by infrared (IR) and low
resolution mass spectograph (LRMS).
The analyses are not adequate for
individual compound identification but
do indicate compound categories and
potential compounds present. Both the
cleaned gas and the water discharged
by the scrubber used for control of
fumes generated by furnace C-2 were
analyzed by gas chromatograph-mass
spectrograph (GC-MS) for exact com-
pound identification.
The IR and LRMS analyses of furnaces
A-1, A-2, and B-1, all of which were
achieving nearly complete combustion
of the furnace gas, indicate a low con-
centration of most organic categories.
Potentially low concentrations of the
carcinogens, indeno(1,2,3-cd)pyrene
and dibenzochrysene isomer, in emis-
sions to the air from furnace A-2 are
indicated by LRMS responses at masses
276 and 302, respectively. Similarly,
low concentrations of the carcinogens,
benzanthracene and benzo(a)pyrene, in
gases generated by furnace B-1 (before
emission control equipment) are indi-
cated by LRMS responses at masses
228 and 252, respectively. No evidence
of potential carcinogens was found in
emissions to the air (primary emission
control system) from furnace A-1. The
scrubber discharge water from furnace
A-1 contained organic compounds with
masses (LRMS analysis) of 228, 252,
256, and 302 which could be the car-
Table 3. Scrubber Efficiencies, Percent"
cmogens, benzanthracene, benzo(a)
pryene, dimethylbenzoanthracene, and
dibenzochrysene isomer, respectively.
The scrubber discharge water from
furnace A-2 contained, in addition to the
cited organic for furnace A-1, masses at
266 and 276 (dibenzofluorene and
indeno(1,2,3-cd)pyrene, respectively).
The scrubbed gases from the covered
furnaces B-2, C-1, and C-2 (measured
before the flares) all coniam similar
types of organic compounds although
the concentration from the B-2 furnace
is lower than that of the other two,
presumably due to the higher scrubber
efficiency for furnace B-2. For these
furnaces, the LRMS analysis indicates
significant concentrations of fused
aromatic organics at masses 252, 266,
276, and 302 which could be carcino-
gens, benzo(a) pyrene, dibenzofluorene,
mdeno(1,2,3-cd)pyrene, and dibenzo-
chrysene isomer, respectively. All scrub-
ber discharge waters from these fur-
naces contain relatively high concen-
trations of organics with masses 228,
252, 256, 266, 276, and 302 which
could be the carcinogens cited previ-
ously. Evidence for potential carcino-
gens (at masses 228 and 252) was
found only in the treated process dis-
charge water from plants C. No evidence
of organic carcinogens was found for
the treated water discharged from
plants A and B.
The GC-MS analysis of the scrubbed
gases from furnace C-2 (before flaring
which should destroy some organics)
gave positive identification of 13 poly-
cyclic aromatic hydrocarbons (PAH)
including the known carcinogens, benz
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tble 5. Estimated Concentrations of Identified PAHs
Estimated Concentrations
in Unftared Gas
Compound
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benzfajanthracene
Chrysene
Benzo(e)pyrene
Benzofkjf/uoranthene
Perylene
Benzo(a)pyrene
Inden o( 1 , 2, 3 - cd)p yrene
Benzo(ghi)perylene
Coronene
Flu or ene*
9-Methylphenanthrene*
Cyclopentafdef) phenanthrene*
Benzo(a)fluorene*
Methyl Pyrene*
Benzo(b)fluorene *
Benzofghijfluoranthene *
Benzo(jjfluroanthene *
Benzo(e)acephenanthrylene *
Anthanthrene*
Mass
178
178
202
202
228
228
252
252
252
252
276
276
300
166
192
190
216
216
216
226
252
252
276
Normalized
Carcinogen Relative Sample
Rating " Concentration
6.8
6.8
10.2
10.6
+ 3.9
± 3.0
0.30
0.06
0.16
+++ 0.61
+ 0.41
1.20
0.38
27.9
0.56
4.0
0.20
0.025
0.025
3.3
++ 1.3
? 1.3
0.31
mg/Nm3
18.3
18.3
27.4
28.5
10.5
8.1
0.81
0.16
0.43
1.64
1.10
3.2
1.0
75.0
1.5
10.7
0.54
0.07
0.07
8.9
3.5
3.5
0.83
DMEG
Air Health
Limit, mg/Nm3
1.6
56
90
230
0.045
2.2
3.0
1.6
2 x W's
1.6
6.5
a±Weakly carcinogenic, + carcinogenic, ++ and +++ strongly carcinogenic, not carcinogenic.
*Tentative identification.
Table 6. Organic Extract Summary Table, Sample No. CI-X
LCI
LC2
LC3
LC4
LC5
LC6
^'Quantity Not Sufficient '"Possible Contamination.
** The data are presented as assigned intensity (from IK and/'or LRMS)/'concentration.
LC7
Total Organics, mg/m3
TCO, mg/m3
GRAV, mg/m3
Category
Aliphatic Hydrocarbons
Halogenated Aliphatics
Aromatic Hydrocarbons
Halogenated Aromatics
Silicones
Heterocyclic Q Compounds
Nitroaromatics
Ethers
Aldehydes
Phosphates
Nitnles
Heterocyclic N Compounds
Heterocyclic S Compounds
Alcohols
Phenols
Ketones
Amines
Alkyl S Compounds
Sulfur ic Acids
Suit oxides
Amides
Carboxylic Acids
Esters
2640
262.7
1.3
100/66.0"
1 0O/66. 0
tOO/66.0"
1OO/66 0"
81 0
59.5
21.5
100/16.2
100/16.2
100/16.2
100/16.2
100/16.2"
31.0 30.4 177
5 70 19.0 8.9
25.3 114 8.8
Assigned Intensity - mg/lm3)
- Q/VS*
100/280
10/0.80
10/0.80
10/0.80
100/80
10/0.80
10/0.80
10/080
10/0 80
10/0 80
100/8.0"
Q/VS* Q/VS*
10/3.0 100/8.0"
62.0 5. 1
19.0 0
43 5.1
- Q/VS*
1 0/0 94
1OO/9.4
100/9.4
1 00/9.4
10/0.94
100/9.4 Q/VS*
70/0.94
10/0.94
10/0.94
100/9.4
100/9.4
10/0.94
491 2
374.7
1165
66.0
82.2
110.2
82.2
17.0
08
08
8.0
0.8
1.74
08
102
0.8
94
9.4
8.94
94
094
094
0.94
9.4
9.4
28.14
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Table 7. Estimates of Furnace Generated POM*
Captured by Control Device
Furnace kg/yr/MW of Capacity
Total Generated by Furnace
kg/yr/MW of Capacity
A-2
B-1
B-2
C-1
C-2
280
ND+
3,600
2,800
1,200
690
280
4.400
3,900
2,800
"Furnace A-1 is atypical.
+/VD = Not Determined.
the ferroalloy industry or about 9,100
tonnes (10,000 tons), on the average,
for each plant. About 30 percent of this
material may contain wastes specifically
listed as hazardous by proposed section
3001 of the Resources Conservation
and Recovery Act (RCRA). About 85
percent of the waste is disposed of in
landfills or lagoons which are unlined.
The dusts and sludges from open fur-
naces may contain about 0.1 percent
organic matter. Sludges from covered
furnaces may contain up to 8 percent
organic matter. Sludges, from covered
furnaces in particular, may contain high
concentrations of polynuclear aromatic
hydrocarbons including known carcino-
gens. Information is presented which
indicates that the POM concentration in
the clarified scrubber water should be
less than its solubility in pure water
(POMs are preferentially absorbed on
suspended solids). Since suspended
solids are generally removed from the
scrubber water before chemical waste-
water treatment and since previous
research has shown that POMs degrade
at a slow rate, it is likely that most POMs
collected by the scrubber accumulate in
solid waste disposal sites and disposal
lagoons. Industry tests indicate that the
dusts from a hard, fairly impermeable
mass (permeability K values of 10"4 to
10~" cm/sec) when wetted and allowed
to dry. Industry data from monitor wells
show virtually no contamination of
groundwater based on analysis for five
metals (Ba, Cd, Cr, Pb, and Hg). No data
are available on organic leaching from
these sludges. To the best of our knowl-
edge, there is no evidence available to
prove or disprove that sealing occurs.
The conclusions of this report are
based, in part, on sampling and analysis
data obtained using EPA/IERL-RTP
Level 1 assessment procedures which
yield final results accurate to within at
least 1 /3 to 3 times the actual value of
the stream sampled. This approach is
used to identify potential environmental
problems and is not in itself sufficient
proof that a problem exists. Appropriately,
therefore, the data are interpreted using
the worst case approximation unless
data exist to prove this approximation
invalid. The major conclusions of this
report are as follows.
1. There are basically two types of
furnaces, open, 86 percent of
installed capacity, in which com-
bustion of the furnace gas occurs
before the emission control
equipment; and covered, 14 per-
cent of installed capacity, in
which the gas is combusted after
passing through the emission
control equipment.
2. The pollution potential of covered
(mix-sealed) furnaces is substan-
tially higher than for open fur-
naces, primarily due to much
higher organic generation rates
by the covered furnaces. However,
mix-sealed furnaces appear to
vary in the rate of organic pro-
duction (kg/MW-hr basis) prob-
ably due to varying rates of
combustion under the furnace
cover. Open furnaces are esti-
mated to generate POM at the
rate of about 100 to 900 kg/yr
(220 to 1,980 Ib/yr) per megawatt
of furnace capacity or 134,500 to
1,210,500 kg/yr (296,500 to
2,668,700 Ib/yr) for all U.S. fur-
naces of this type The covered
furnaces are estimated to gener-
ate POM at the rate of about
1,230 to 11,080 kg/yr (2,710 to
24,430 Ib/yr) per megawatt of
furnace capacity or 208,800 to
1,878,800 kg/yr (460,300 to
4,120,000 Ib/yr) for all U.S. fur-
naces of this type. Control de-
vices, which are in use on all U.S.
furnaces, remove most of this
material from the furnace gas.
Thus, the estimated nationwide
POM generation rates (estimated
rates before the emission control
devices) are in the same order of
magnitude as POM generation^
rates (before control devices) of^
slot type coke ovens, a major
POM emitter, which are estimated
to be 317,000 to 3,200,000 kg/yr
(700,000 to 7,000,000 Ib/yr) for
all U.S. coke ovens.
3 The industry generates about
363,000 tonnes (400,000 tons)
of solid waste annually, about 85
percent of which is disposed of in
unlined lagoons and landfills.
Although the wastes contain
known and/or suspected hazard-
ous inorganic and organic mate-
rials, there is some evidence that
the wastes are self-sealing and
that heavy metals do not leach
into the groundwater.
4. The industry consumes about 9
million megawatt hours of elec-
tricity annually, 6 percent of
which is used for pollution con-
trol. Open and mix-sealed fur-
naces use up to 5 times as much
energy for pollution control as
does a typical totally sealed fur-
nace.
5. For the six furnaces tested, there
appears to be no significant dif-
ference in the kg of paniculate
generated/megawatt hour of
furnace power (before emission
control) as a function of furnace
size, type, or product being man-
ufactured. There does appear to
be a difference in the kg of partic-
ulate (per megawatt hour of fur-
nace power) in the gas discharged
from the scrubber, which appears
to be related to scrubber design
and pressure drop, but may also
be a function of furnace type
and/or product being manufac-
tured.
6. Scrubbers appear to be less ef-
ficient for capturing organics
than for particulate capture.
7. Low resolution mass spectro-
graphic analysis indicates the
potential presence of carcinogens
in the cleaned gas from the
scrubbers, before it was flared,
from four of five furnaces tested
(the exception being one mix-
sealed furnace in which complete
undercover combustion was ap-
parently occurring), and in the
gas from one open furnace which
was tested before emission
control.
8. Low resolution mass spectro-
graphic analysis indicates the
presence of potential carcinogens
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in all scrubber discharge waters
and in the plant discharge water
from only one plant (no longer
operating) of the three tested.
9. Analysis of samples of one mix-
sealed furnace by GC-MS tech-
niques gave positive identification
of known carcinogens in the
cleaned gas discharged by the
scrubber (but before passing
through the flare which may
destroy some of the organics) and
in the scrubber discharge water
(before wastewater treatment).
Two of these carcinogens could
exceed DMEG1 values by factors
of up to 200 and 80,000 respec-
tively, if significant destruction
does not occur in the flare. These
data provide strong evidence that
the preliminary identifications
listed above in 7 and 8 are prob-
ably correct.
10. U.S. production of ferroalloys has
declined during the last decade to
about 1945 levels. Imports have
risen from about 2.4 percent of
domestic consumption in 1945 to
over 40 percent in the years since
1975.
11. Unless action is taken soon to
stem the tide of imports, the
continued viability of the U.S.
industry is questionable.
12. There are noplanstoexpandU.S.
production capacity. Rather, some
furnaces are idle, some plants
are being closed, and some older
furnaces are being replaced by
larger, more efficient furnaces.
13. Based on information obtained in
these tests, we must conclude
that a potential for a significant
multimedia environmental prob-
lem exists with ferroalloy manu-
facture and that this potential is
significantly greater for plants
using mix-sealed and sealed fur-
naces than for those using open
furnaces. It has not been estab-
lished that a real environmental
problem exists in any of the three
mediaair, water, or solid waste.
Recommendations
More accurate testing should be done
to quantify the pollutants produced by
'Kmgsbury, G L , etal "Multimedia Environmental
Goals for Environmental Assessment - MEG Charts
and Background Information Summaries," Vol Ill-
Categories 1-12, EPA-600/7-79-176a (NTIS PB80-
15108), and Vol IV-Categones 13-26, EPA-600/
-79-176b(NTIS PB80-115116), August 1979
the furnaces and determine how much
is ultimately discharged to the environ-
ment through any and all three media. If
these tests should prove that unaccept-
able amounts of pollutants are emitted,
or are disposed of in an environmentally
unsound manner, work should be initi-
ated to determine if the public is being,
or is likely to be, endangered. If these
studies indicate public endangerment,
studies should be undertaken to reduce
pollutant releases from the industry
Specifically, the following additional
work is recommended. More accurate
sampling (i e , isokmetic, duct traverse,
integrated composite water sampling)
and analysis (GC-MS, for example) need
to be used to quantify discharges from
the plants to all media. For plants using
only open furnaces and capturing and
disposing of only dry dust (baghouse
control system), sampling will be re-
quired for emissions from the baghouse
and for surface water runoff and ground-
water intrusions from the dust disposal
site A few locations control emissions
from open furnaces with scrubbers or
slurry the dust captured by the bag-
house. The number and size of these
facilities are probably not large enough
to warrant detailed testing. Sampling in
the gas stream before the control device
(baghouse) and of the collected bag-
house dust is also recommended since
these tests will allow a measure of
control efficiency for the contaminants,
a measure of contaminants entering the
disposal sites, and an indication of
possible emissions in the event of
control device failure (bag rupture, etc.).
Quantifying emissions to the air from
covered (mix-sealed and sealed) fur-
naces is extremely difficult since the gas
is flared on discharge to the atmosphere
At present, there are no established
techniques for measuring emission
rates from flares. It is recommended,
therefore, that the gas be sampled in the
duct after the scrubber and before the
flare This should provide a reasonable
estimate of particulate emissions, al-
though some change in mass is to be
expected since flaring may change the
form of some of the particulate compo-
nents and is expected to burn off some
of the organics on the particulate matter.
Determining the actual organic emis-
sion rate is complicated by the fact that
the flare will destroy some of the organic
matter and the percentage destruction
(for total organics or for individual
compounds) cannot be accurately mea-
sured. As a first approximation, it can be
assumed that the flare is 100 percent
effective and the emission rate calcu-
lated based on the percent of time that
the flares are not operating. Other
assumptions about flare efficiency
could be made. If adequate methods are
developed, an actual assessment of
flare effectiveness should be made.
The wastewater discharged by the
plant should be analyzed for priority
pollutants including polynuclear aro-
matics. The possibility of leaching
inorganics and organics intotheground-
water at disposal sites and lagoons
should be examined.
It is recommended that, in conjunction
with the above tests, the water dis-
charged by the scrubbers on the furnace
be tested since this provides informa-
tion as to the control efficiency of both
the scrubber and the wastewater treat-
ment system.
If the above test should prove that
unacceptable amounts of pollutants are
emitted or are disposed of in an environ-
mentally unsound manner, work should
be initiated to determine if the public is,
or is likely to be, endangered. To ac-
complish this, modeling studies for the
pollutants of concern should be done to
determine the potential impact on the
population surrounding a plant.
If the weight of evidence gathered
indicates public endangerment, work
should be initiated to reduce pollutants
emitted by the industry. While we
cannot predict with certainty which
pollutants would be involved or which
media would have the most impact, we
can suggest some areas in which addi-
tional work might be fruitful. Included in
the suggested efforts below are some
already being instituted by the industry.
1. Improve flare design and opera-
bility.
2. Improve scrubber efficiency,
particularly for organics.
3. Reduce gas volume from open fur-
naces, possibly by the use of close
hooding.
4. Investigate the possibility of con-
trolled undercover combustion in
mix-sealed and sealed type fur-
naces for organic matter destruc-
tion. *
5. Investigate improved water treat-
ment methods, including clarifica-
tion and filtration for improved
suspended solid removal and an
investigation of the applicability of
reuse and/or recycle of waste-
water since this has the potential
for significantly reducing mass
emissions of suspended solids (on
US GOVERNMENT PRINTING OFFICE 1981 757-012/7243
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which polycyclic aromatic hydro-
carbons can be absorbed) and
dissolved materials.
6. Investigate alternate methods for
treatment or disposal of solid
wastes generated.
4
C. W. Westbrook and D. P. Daughterly are with Research Triangle Institute,
Research Triangle Park, NC 27709.
Robert C. McCrillis is the EPA Project Officer (see below).
The complete report, entitled "Level 1 Environmental Assessment of Electric
Submerged-Arc Furnaces Producing Ferroalloys," (Order No. PB81 -210 106,
Cost: $24.50, 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
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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