EPA-450/3-74-013
May 1973
NATIONAL EMISSIONS
INVENTORY
OF SOURCES
AND EMISSIONS
OF
PHOSPHORUS
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Water Programs
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
-------
fcPA-450/3-74-013
NATIONAL EMISSIONS INVENTORY
OF
SOURCES AND EMISSIONS
OF
PHOSPHORUS
by
GCA Corporation
GCA Technology Division
Bedford, Massachusetts 01730
Contract No. 68-02-0601
EPA Project Officer; David Anderson
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Water Programs
Office of Air Quality Planning and Standards
Research Triangle Park, N. C. 27711
May 1973
-------
This report is issued by the Environmental Protection Agency to report technical
data of interest to a limited number of readers. Copies are available free of
charge to Federal employees, current contractors and grantees, and nonprofit
organizations - as supplies permit - from the Air Pollution Technical Information
Center, Environmental Protection Agency, Research Triangle Park, North
Carolina 27711, or from the National Technical Information Service, 5285 Port
Royal Road, Springfield, Virginia 22151.
This report was furnished to the Environmental Protection Agency by GCA Corp-
oration, Bedford, Massachusetts, in fulfillment of Contract No. 68-02-0601. The
contents of this report are reproduced herein as received from GCA Corporation.
The opinions, findings, and conclusions expressed are those of the author
and not necessarily those of the Environmental Protection Agency. Mention of
company or product names is not to be considered as an endorsement by the
Environmental Protection Agency.
Publication No. EPA-450/3-74-013
-------
TABLE OF CONTENTS
SECTION TITLE PAGE
ABSTRACT vii
ACKNOWLEDGEMENT V iii
I INTRODUCTION 1
A. PURPOSE AND SCOPE 1
B. CONCLUSIONS 2
II OVERALL U.S. MATERIAL FLOW CHART FOR PHOSPHORUS 4
A. U.S. PRODUCTION AND ORE PROCESSING 4
B. IMPORTS AND EXPORTS OF PHOSPHATE ROCK 4
C. INDUSTRIAL INVENTORY 4
D. FERTILIZER INDUSTRY 6
E. IMPORTS AND EXPORTS OF FERTILIZER 6
F. ELEMENTAL PHOSPHORUS INDUSTRY 6
G. OTHER USES
III SOURCES AND ESTIMATES OF PHOSPHORUS-CONTAINING
EMISSIONS 8
A. DATA PRESENTATION AND ACCURACY 8
B. DEVELOPMENT OF EMISSIONS ESTIMATES - 1970 16
C. SUMMARY OF PRINCIPAL EMISSIONS 31
IV REGIONAL DISTRIBUTION OF PRINCIPAL SOURCES AND
EMISSIONS 33
V NATURE OF EMISSIONS 37
A. FERTILIZER EMISSIONS 38
B. ELEMENTARY PHOSPHORUS EMISSIONS 38
C. PHOSPHORIC ACID PLANT EMISSIONS 39
D. OTHER SOURCES 39
ill
-------
1ABL! OF CONTENTS (continued)
SECTION i TITLE PAGE
VI UfDATING OF EMISSIONS ESTIMATES 41
A, VERIFICATION OF CURRENT ESTIMATES 41
B. PERIODIC REVIEW OF ESTIMATES 41
VII REFERENCES 43
IV
-------
TABLE NO.
1
LIST OF TABLES AND FIGURES
TITLE
SOURCES AND ESTIMATES OF PHOSPHORUS-
CONTAINING EMISSIONS
UNCONTROLLED PARTICULATE EMISSION FACTOR
(Ib/ton of Rock)
PRINCIPAL SOURCES OF PHOSPHORUS-
CONTAINING EMISSIONS - 1970
REGIONAL DISTRIBUTION OF PRINCIPAL SOURCES
AND EMISSIONS
PHYSICAL PROPERTIES OF PHOSPHORUS
PAGE
18
32
34
37
FIGURE NO.
PHOSPHORUS-MATERIAL FLOW 1970
-------
ABSTRACT
A national Inventory of the sources and emissions of the element
phosphorus was conducted The study included the preparation of an
overall material flow chart depicting the quantities of phosphorus moving
from sources of roicdng emd importation througli all processing and re-
processing steps f:o uJ.tiwate use and final d,isposl£ioa( All, I»;|OK sotcecefl
of phosphorus-containing emissions were identified an& their phosphorus
emissions into the atmosphere estimated. A regional breakdowa of these
sources and their emissions was also provided. The physical and chemical
nature of the phosphorus-containing emissions was delineated to the
extent that information x*as available/ and a methodology for updating
the results of this study every two years^ sas reeammesxdetL
Vll
-------
ACKNOWLEDGEMENT
The continued cooperation and dedication of Mr. Carl Spangler of
EPA, who served as Program Monitor until his death is deeply appreciated.
GCA wouli lik« to extend thanks to Me. David Anderson and Mr. James
Souther land of EPA for their cooperation in the preparation of this
s tudy.
In addition, special thanks are also due to Mr. James Barber, TVA,
and The Fertilizer Institute, Washington, D.C., who provided significant
technical inputs to this program.
VI11
-------
I. IMfROPUGflQH
A. PURPOSE AND SCOPE
The Monitoring and Data Analysis Division, Office of Air
Quality Planning and Standards of the U.S. Environmental Protection
Agency (EPA) has contracted with GCA Technology Division to conduct a
national inventory of the sources and emission, of i'.he element phospfeoms.
The purpose of the study was to define as accurately as possible, based
on existing and available published and unpublished informations the
levels, nature and sources of phosphorus-containing emissions for defined
geographic regions throughout the United States.
The scope of this program is outlined below:
Develop an overall material flow chart
depicting the quantities of phosphorus
moving from sources of mining and impor-
tation, through all processing and
reprocessing steps to ultimate use and
final disposition as far as the move-
ments can be traced.
identify all major potential phosphorus-
containing emission sources and estimate
the total quantity of phosphorus
emitted to the atmosphere from each source.
Emission factors and level and types of
air pollution control will also be pro-
vided for each of these sources to the
extent that available information permits.
Define those sources which contribute at
least 80% of the total emissions of
phosphorus.
, Provide a regional breakdown of these major
sources and their emissions.
Present the nature of the phosphorus-
containing emissions for each of these
major sources Including a delineation of
their physical and chemical form and par-
ticle size distribution to the extent
that information is available.
Provide recommendations as to a methodology
for updating the results of this study
every two years,
-------
B. CONCLUSIONS
1. Material Flow
Based on available data, 11,998,000 tons o£ phosphate
rock as ?2^s were reduced in the United States. Only a small quantity
was imported (41,000 tons of contained P.,0,.) and utilized almost
exclusively in animal feed applications because of its low fluorine con-
tent.
Approximately 8,350,000 tons of PnO,. were consumed domes-
tically with about 78 percent utilized in the manufacture of fertilizers.
The other primary use was as an additive in soaps, detergents and water
treatment products.
Certain assumptions made in preparing the above estimates
are explained in detail in Section II.
2. Principal Emissions Sources
The principal source category of phosphorus-containing
emissions is the fertilizer manufacturing industry which contributed an
estimated 82 percent of the emissions generated in the U.S. in 1970.
Triple superphosphate and ammonium phosphate plants were the largest
source categories, contributing 35,700 and 30,700 tons/yr. respectively.
Approximately 19 percent of P^Oc containing emissions resulted from
processes outside the phosphorus industry; coal combustion and iron man-
ufacture accounted for 13 percent and 4 percent respectively.
3. Regional Estimates
The region in the U.S. in which most of the phosphorus is
estimated to be emitted is Region 4 (Alabama, Florida, Georgia, Kentucky,
Mississippi, North Carolina, South Carolina and Tennessee), This
region accounted for 84,400 tons of PoOc or about 53 percent of the total
emitted in the U.S. This region also had the largest emission density,
estimated at 0.22 tons of P^Oc Per square mile - year.
-------
4, Nature of Emissions
Phosphorus emissions from rock processing and the ferti-
lizer industry, which is the most significant emissions source, are
primarily in the form of calcium and ammonium phosphate which are cate-
gorized as stable compounds. Little information was available on the
particle size distribution of these emissions.
Emissions from elemental phosphorus manufacture are
initially P~ and P, fumes which oxidize quickly to form p 0,.. This com-
pound is very hygroscopic and is therefore expected to form phosphoric
acid (P205 + 3H20 -» 2H3P04).
5- Degree of Control
The ovfciall level of control of phosphorus-containing
emissions is estimated to have been about 87 percent in 1970. An esti-
mated 1,203,400 tons of P^O,. were generated before control and 160,400
tons were estimated after control. The major sources of P^O,. emissions
before control were phosphate rock processing (218,000 tons/yr.), fer-
tilizer manufacturing (662,000 tons/yr.), and coal combustion (115,000
tons/yr.).
-------
II. OVERALL U.S. MATERIAL FLOW CHART FOR PHOSPHORUS
Figure 1* presents a flow diagram depicting the total quantities
of phosphorus products moving from sources of mining and importation
through the processing and reprocessing steps to ultimate use and final
disposition. Each of the sources is discussed below.
In the following discussion all tonnages are expressed in terms
of equivalent tons of 100 percent P«0, unless specifically stated other-
wise.
A.. U.S. PRODUCTION AND ORE PROCESSING
Three major areas in the U.S. mine and beneficiate phosphate
rock: Florida and North Carolina; Tennessee; and the Western States.
Total 1970 domestic production was 11,998,000 tons of phosphate rock.
Production from Florida and North Carolina accounted for about 81 per-
cent of which 98 percent was for agricultural use; Tennessee, about 8
(1 2)
percent; and the Western States, 11 percent. '
The actual P7Cv content in the ore varies from seven to 18
(~ „/
percent in Florida, to 24 to 33 percent in the Western States. This
percentage usually dictates the method of beneficiation and its consump-
tive usage.
B. IMPORTS AND EXPORTS OF PHOSPHATE ROCK
In 1970, 3,528,000 tons of phosphate rock, about 30 percent
of the total domestic production, were exported mainly to Japan, Canada,
West Germany and Italy. The imported phosphate rock, around 41,000
tons, was chiefly used as animal feed because of its low fluorine con-
tent.
C. INDUSTRIAL INVENTORY
Because of a reduction of phosphate rock demand, largely due
*ai:
190,000 tons.'
to the curtailed use of phosphorus in detergents, inventory increased by
(1)
* Data in Figure 1 and in this section are left unrounded, for purposes
of information control. On average, the typical statistic is accurate
to within 10 percent, in the opinion of the authors.
-------
Figure 1. Phosphorus 1970 material flow
(Thousand Tons Contained P?0,-)
-------
D. FERTILIZER INDUSTRY
Phosphorus is one of the chief active components in commercial
fertilizer. Many grades, both solid and liquid, are made from the
numerous compound . U.S. agriculture used about 6,500,000 cons of phos-
phorus primarily .?•< normal superphosphate (1,366,000), triple super-
phosphate (2,250,000 tons), and diaramonium phosphate, DAP, (an esti-
mated 1,750,000
More than 90 percent of the 3,772,000 tons of phosphoric acid
made from the wet process goes to the fertilizer industry. Therefore,
about 3,500,000 tons of wet process phosphoric acid was used to make
triple superphosphate and DAP.
An estimated 200,000 tons of other fertilizer products, such
as pulverized phosphate rock, fertilizer filler, and other fertilizers
went into agricultural application.
E. IMPORTS AND EXPORTS OF FERTILIZER
Exports of superphosphates, ammonium phosphates and mixed
fertilizers amounted to 270,000 tons. Triple superphosphates from
Mexico and ammonium phosphate from Canada accounted for most of the
300,000 tons imported by the U.S. for fertilizer use.^ '
F. ELEMENTAL PHOSPHORUS INDUSTRY
The production of elemental phosphorus is another major user
of phosphate rock. In 1970, 1,709,000 tons were consumed, ' of which
an estimated 1,200,000 went into the production of thermal phosphoric
f *•!•. f\\
acid and superphosphoric acid. ' Most of the phosphoric acid was
consumed in plating and polishing (250,000 tons), and the production
of sodium phosphates for soaps, detergents and water treatment (760,000
tons). Approximately 500,000 tons of elemental phosphorus were used
to make many compounds such as red phosphorus, phosphorus chloride,
phosphorus sulfide, zinc and copper phosphide, and many other organo-
phosphorus) compounds.
-------
G. OTHER USES
Calcium phosphates, produced from phosphoric acid and
elemental phosphorus, go primarily into animal feed supplement, with the
rest used in baking power, and as a polishing agent in dentifrice.
Including the imported rock, about 225,000 tons were consumed in the
manufacture of animal feed.
Other uses, amounting to approximately 100,000 tons, were the
of calcium phosplu
phates, and their derivatives,
manufacture of calcium phosphates, ammonium phosphates, sodium phos-
(1,5)
-------
III. SOURCES AND ESTIMATES OF PHOSPHORUS-CONTAINING EMISSIONS
A. DATA PRESENTATION AND ACCURACY
Table 1 presents a summary of the data froa which phosphorus-
containing emissions in terms of PoO- were estimated for ail major
potential sources. Each of the columns comprising this table will be
discussed below.
!• Emission Factors
Except where indicated, this gives the pounds of total
particulates emitted per ton of production. Such considerations as:
variations in process conditions among
individual plants comprising a source
category
inaccuracies in existing data
a limited quantity of existing data,
may, however, result in an average emission factor for a source category
varying by more than an order of magnitude from the value presented. In
recognizing the need to indicate the level of accuracy of these emission
factors, a reliability code is presented along with each emission factor
value appearing in the Table. This reliability code system is described
below and is based on the system utilized in EPA Document No. AP-42,
"Compilation of Air Pollutant Emission Factors";
A: Excellent
This value is based on field measurements
of a large number of sources.
B: Above Average
This value is based on a limited number
of field measurements.
C: Average
This value is based on limited data and/
or published emission factors where the
accuracy is not stated.
-------
TABLE 1
SOURCES AM) ESTIMATES OF PHOSPHORUS-CONTAINING EMISSIONS
1. PHOSPHATE MINING
a, Land-Pebble
b. Hard -Rock
c Underground
2, .PHOSPHATE KOCK PROCESS IHG
Drying
Grinding
Calcining -Cool ing
Material Handling
3. PHOSPHORIC ACID (WET PROCESS)
Grinding
Material Handling (ore)
Reactor, Filter, Absorber
Uncontrolled Par-
ticulate Emission
Factor
(Ib/ton)
0.
,5
.3
15.
20.
40.
1.
20.
2.0
0,25**
(Kg/l03Kg)
0.
,25
.15
7.5
10.
20.
0.5
10-
1.
.12**
Reli-
abil-
ity
Code
(B)
(D)
(t»
(B)
(C)
(C)
(C)
(C)
(C)
(B)
Pro-
duct ion
Level
(10** tons yr)
115.
10,2
. 5
35.
35.
4.0
39-
12.
12 .
3.78
". P2o5
in
Emissions
107.
26%
28%
3CT*
307.
30%
307,
30%
3(T
Reli-
abil-
ity
Code
-------
TABLE 1 (continued)
4. FERTILIZERS - (GEHERM.:)
Katerlal Hindi Ing
Screening
Btggtog
Bulk Loading
«• NORMAL SMWHOS.
Drying
CooliBI
P roquet Grinding
b. TRIPLt SUPERPHOS.
Product Grinding
Dryiag
Cooling
Uncontrolled P*r-
E leu late Emiaftion
Factor
(Ib/ton)
6.0
2.0
2.0
1.0*»
1.0
105.
90.
0.5
0,5
10$,
90.
(Kg/lOJKg)
3 _
1.
1.
0.5**
0.5
S2.5
45.
0.2$
0.25
52.5
45.
Reli-
abil-
ity
Code
fc\
w t
(C)
(C)
(C)
(C>
(C)
(C)
(C)
(C)
(C)
Pro-
duct iOD
Level
(10* ton«/yr)
7. 24
7.24
6.5
3.2
3.2
1.J7
J.37
l.JT
3.25
3.25
3,25
% P205
in
Emissions
30t
*
*
*
*
*
*
*
*
* ~
Reli-
abil-
ity
Code
/n\
(B)
(B)
P2<>5
Before
Controln
(103 tona/yr)
6t.
• 0
2.2
6.5
-
1.6
72.0
61.7
.3
.8
171.
146.
£itl-
m*fe*)
•.cvel of
Esi^i ion
Con'i'ot
t'Tl,
VI.
r.57.
iHV
or.
90S
»07.
807.
607.
907.
»W.
P205
Emissions
After
Controls
(I03 coB»/yr)
1 , 3
2,2
1.0
1,6
1.6
7.2
6.2
.1
,2
17.1
H.4
-------
TABLE 1 (continued)
c. AMMONIUM PHOS.
Asraoniatar-Granulator
Drying
Cooling
5. FECTIilZER AmiCMTIOH
Bagging-Bulk Loading
Field Spreading
6. ELEMENTAL PHOSPHORUS
Ore Hand 1 log
Grinding
Briquetting, Sintering or
Nodullzlng
Furnace Operations
Flare*
Uncontrolled Par-
ticulate Emission
Factor
(Ib/ton)
30.
55.
25.
1.0
4.0
2.0
20.
1.3
1.0
1.8
(Kg/103Kg)
15.
27.5
12.5
0.5
2.
1.
10.
0.65
0.5
0.9
Reli-
abil-
ity
Code
(B)
(D)
(C)
(C)
(D)
(C)
(B)
(B)
(B)
Pro-
duct Ion
Level
(10° tons/yr)
3,5
3.5
3.5
6.5
6.5
6.46
6.46
6.46
6.46
6.46
*P2°5
la
Emission*
*
*
*
*
*
251
25t
***
***
***
Reli-
abil-
ity
Code
(I)
(B)
P205
Before
Controls
(103 tona/yr)
52.5
96.0
43.8
3.2
13.0
1.6
16.2
4.2
3.2
5.8
E»ti-
nated
Level of
Emisa ion
Control
85S
85%
in
5«
ox
01
9n
60X
m
ot
'205
Emits ioru
After
Controli
(103 toa»/yr)
7.9
14.4
6.6
1.6
13.0
1.6
.5
1.7
.3
5.8
-------
TABLE 1 (continued)
7. PH05 PHOBIC ACID (THERMAL)
Hydr»tor-Ab«orber
8. SODIUH PHOSPHATE
Drying-Cool log & C»lctning-Coollng
Material Handling
Grinding
»«*gi"«
9. SOAPS & DETERGENTS
Mixing
10. CALCIUM PHOSPHATE
D« jrlog-Cool 1«*
Material Hand 1 Ins
Grinding
Bagging
M«C*rl
(D)
(C)
(0
(C)
(B)
(C)
(C)
(C)
CC)
Fro-
due £ Ion
Level
(10* tono/yr)
1.2
.8
.8
.8
.8
.6
.2
.2
.2
.2
,2
^ F2o5
In
Emiss Ions
*
*
*
it
*
*
*
*
*
*
*
Reli-
abil-
ity
Code
-
-
-
-
-
-
-
-
-
-
-
P205
Before
Control*
(lQ3 tons/yr)
-
24.
0.8
8.0
-
12.
t.O
.2
2.0
-
.2
Eitl-
EUted
Level of
Emit lion
Control
«*
»0l
on
»m
**
581
*ox
on
»n
**
ox
F205
Et9l8«lQCIS
After
Control*
(103 con«/yr)
1.*
2.4
.8
.2
.4
.2
.6
.2
.1
.1
,2
-------
TABLE 1 (continued)
11. PLATING, POLISHING, 6. MISC.
Phos. Acid Bath
12. INADVERTENT S_QDRCES
a. Refuse Incineration
b. Iron Mfg.
c. Steel Mfg.
d. Cement Mfg.
e. Fuel Oil Combustion
f. Coal Combustion
Uncontrolled Par-
ticulate Emission
Factor
(Ib/ton)
0.25**
NA
ISO.
25.
NA
NA
NA
-------
D: Below Average
This emission factor is based on
engineering estimates made by
knowledgeable personnel.
^ " Level of Production Activity
This column depicts the quantity of material produced
(unless otherwise stated) annually. When multiplied by the emission
factor an estimate of the total particulate emissions for that source
in Ibs, per year is obtained.
The values in this column are based on the material flow
calculations presented in Section II. Consequently, they have the same
+ 10 percent accuracy as do the material flow values,
3- Percent P^,0C In Emissions
>
The method of analyzing or assaying a dust sample for the
amount of an element it contains determines to a large extent the
reliability of the data. For example, analytical chemistry techniques
for dust containing substantial fractions of metal can be accurate to
within a small percentage. On the other hand, optical spectroscopy
methods for determining concentrations on the order of parts per million
can be inaccurate by a factor of 2, Because of this variability, the
reliability codes discussed above for the emission factors are also
utilized to estimate the relative accuracy of the percentage values
listed in Column III.
4. Levels of Phosphorus Emissions Before Control
The values in this column are derived by multiplying the
values in columns 1-3. The result is converted to tons /year of emissions
before control.
5. Estimated Level of Emission Control
The overall effectiveness of control for a source cate-
gory is based on two factors:
the portion of the processes which are under control
the typical degree of control
14
-------
For example if 60 percent of vertical roasters have some type of parti-
culate emission control, and these include both scrubbers and precip-
itators such that the apparent weighted average efficiency of control is
85 percent, the overall control effectiveness is estimated to be 60 x
85 = 51 percent.
The accuracy of control efficiency data varies with the
degree of control. For a wet scrubber operating at 80 percent efficiency,
i.e. passing 20 percent material, the actual emission may safely be
assumed to be between 15 and 25 percent because of the relative ease of
making determinations at this level. Thus the emissions after control
may be assumed to be accurate within + 5/20 or 25 percent. On the other
hand, for a baghouse reported as being 99 percent efficient, or passing
only 1 percent of the material, the actual emission may vary from 0,5 to
perhaps 2 percent because it is frequently difficult to make low-level
measurements with accuracy. In such a case, the resulting emission data
could be in error by a factor of 2.
Unless otherwise specified, it is assumed that the
reported overall level of particulate control applies equally to all
phosphorus-containing particles, independent of size, resistance and
other important collection parameters. This assumption results in a
correct estimate of phosphorus emissions after control when the particu-
late is chemically homogenious, i.e. phosphorus is contained in the
same concentration in all particles. If however, phosphorus is concen-
trated in certain particles and in addition the efficiency of the con-
trol equipment is not uniform for all particles, then the utilization of
an average control level is less valid for calculating phosphorus emis-
sions after control. Data on the preferential control of phosphorus-
containing particles is seldom available, but is included in this report
when possible.
The accuracy of estimating the level of control for a
specific source category is dependent on the quality of available data.
The investigators feel that, in general, the level of control data will
contribute an accuracy to the resulting emissions estimates within +
25 percent.
15
-------
6 . Emlssimis
The values In this column are derived by multiplying the
values in Column 4 by the value (100 minus estimated Level of Control)*
B , miVELOPhKRT OF EMISSIONS ESTjmTES_1970
There are three major areas in the U.S. where the phos-
phate ore is mined; Florida; Tennessee, North Carolina and vicinity; and
Western States. The mining techniques which vary with type and grade of
rock can be classified into three emissions categories: open pit methods
for Florida's land-pebble phosphates; open pit methods for hard rock
phosphates; and underground mining,
a. Florida's Land-Pebble Phosphates
Two districts, the central land-pebble and the
northern land-pebble produce more than 99 percent of Florida's phosphate
rock production. Including North Carolina, 115 million tons of rock
were mined. In these places the deposits occur as pebbles ranging
from 1/2-inch in diameter to fine sand-sized grains. The ore matrix
consists of about 1/3 unconsolldated mixture of phosphate pebbles and
/O Q\
fragments of phosphatized limestone, 1/3 silica sand and 1/3 clay, '
The PpO,. content ranges from 7 to 18 percent- The mining is done by
open pit methods using draglines. After stripping about 20 feet of
over-burden, the ore is removed, broken up by water jets and stacked at
natural ground level in a prepared suction well such that it can be
pumped in a slurry form to the washing plant. This wet operation
essentially produces no particulate emissions,
b. Open Pit Mining of Hard Rock Phosphates
Hard rock phosphates are found mostly in Tennessee
and the Western. States. The phosphate rock occurs as coherent plates
called lump rock whose grade varies from 18 to 34 percent P^O,-* Drag-
lines mine all of Tennessee's (including Alabama's) production of 5.6
million tons and an estimated 90 percent of the 5.0 million tons
16
-------
produced in the Western States. ^ The crude ore is either slurried or
hauled by trucks or railroad cars to the washer plant where the ore is
beneficiated. The mining, loading and hauling will cause small amounts
of particulates. A comparison with other mining operations suggests
that the particulate emission factor is less than ,5 Ib per ton of rock
used for these operations, ' Since controls are not applied, total
emissions are less than 700 tons P-jO,. per year.
c. Underground Mining
Underground mining, which accounted for about 10 per-
cent of the 5.0 million tons of phosphate rock produced in the Western
C9\
States, is fading in practice. Mining is restricted mainly to high
grade beds (> 31 percent P?0P) which are at the top and base of the
phosphatic shale series. The high grade rocks, which vary in size, are
used in the production of fertilizers and phosphoric acid, while phos-
phate shale, which is separated by limestone from the high grade ore and
contains about 24 percent P«0r, is used in the production of elemental
phosphorus. The mining method depends on the depth of the ore. Shallow
shales are mined by such open-pit methods as top slicing and cut^and-fill,
/ Q\
while deep shales are mined underground by room and pillar staging.
The ore is transported to plants by railroad cars. The particulate
emission of .3 Ib. per ton of rock processed was assumed to be less than
open pit mining of hard rock because the mining is underground. Total
controlled emissions are below 100 tons P^O,. per year (Table 1).
2. PhosphateRock Processing
The mined ore is usually beneficiated, crushed and categor-
ized according to a size and grade suitable for subsequent operations or
according to purchaser's specifications. The processing operations dis-
cussed here are those which prepare the ore for all the other operations
discussed in the subsequent sections-. Emissions are from washing, grind-
ing, drying, calcining-cooling, material handling at transfer points,
conveying, systems, and discharge points at storage hoppers, and from
open storage.
17
-------
BenefIciation removes the impurities and improves the
grade of the ore by washing, calcining, flotation or combinations of
these. The choice depends on the grade and size of the rock. Emissions
are negligible from washing and flotation, which is practice:! extensively
in Florida and tAxifetHteiy in other regions of the southeast and the
Western States. Calcining, especially, is practiced in the Western
States to burn out the organic material contained in the ore; thus up-
grading the phosphate content by 2 to 3 percent (estimated: 4 x 10 TPY
calcined). In some cases where the ore is not calcined, it is dried
before grinding (estimate: 35 x 10 TPY). Only the course rock, >14
mesh, found in Florida is ground, while in the other states more signifi-
cant grinding is done (estimate: 35 x 10 TPY ground). These estimates
are made in the absence of information as to the quantity of material
processed in each of these operations. The estimates refer to quantities
of phosphate rock after the removal of two to three times as much waste
material. This cleaned rock contains about 30 percent P^O...
Several sources of emission factors for these processes
are presented in Table 2:
TABLE 2
UNCONTROLLED PARTICULATE EMISSION FACTOR (Ib/ton of rock)
Drying
Grinding
Calcining
Material Handling
Emission controls include cyclones and scrubbers. In
combination they reduce particulate emissions 95 to 99 percent.
Midwest Research published control efficiencies of 94 percent for drying
and 97 percent for grinding. They also estimated a 95 percent con-
trol efficiency for a cyclone scrubber system for a calcining process.
A moderate 50 percent control is estimated for the various processes con-
tributing to material handling losses.
Midwest Res.
12
2
40
2
'10) (in (12) GCA
EPA Source Tests Estimate
15
20
—
2
13-62
133
.02-1.32
15
20
40
1
18
-------
3. Wet-grocess Phosphoric Acid
Wet-process acid is made commercially in the U.S. by the
complete acidulation of ground phosphate rock using suifune acid. The
reaction is carried out continuously in single or multiple-tank reactors.
The considerable amount of heat generated is removed by blowing air over
the hot slurry surface or vacuum cooling part of the sluiry a;.d recycl-
ing it back into the reactor. Then, the calcium sulfato is precipitated
and filtered in circular, horizontal tilting-pan vacuum filters. The
concentration of the acid is increased from 32 percent P^Cv to about 54
percent P«0,. in vacuum evaporators.
Prior to acidulation, the phosphate rock has to be finely
ground in a large ball mill. The ground rock is then sent to an air
classification system wherr over-sized particles are recirculated back to
the ball mill. The uniform size increases the percent conversion to
acid. Although no emission factor data have yet been reported for these
ball mills, the emission is assumed similar to the rock grinding dis-
cussed earlier. Baghouses or eye lone-scrubber systems assumed to have 97
percent efficiencies are generally employed to control emissions. Approxi-
mately 12 million tons of rock are milled in preparation for wet process
acid manufacture. With a P?0, content of 30 percent, an estimated 36,000
tons per year of uncontrolled PpO- emission are generated. After control,
an estimated 1,100 tons of P?0^ emissions are emitted.
Miscellaneous processes of handling the ore before and
after grinding also contribute some emission. These processes are esti-
mated to generate 2 Ibs/ton of product, twice the rate used above due to
the finer grinding employed. Following an estimated 50 percent control,
1,800 TPY of P205 are emitted.
Although the major pollutant from reactors, filters and
evaporators is fluoride, phosphoric acid mist is also emitted. Other
sources include vents from acid splitter boxes, sumps, and phosphoric
acid tanks. These are often vented to scrubbers, which although specifi-
cally designed for fluoride emissions, have estimated efficiencies from
(13)
98,5 to 100 percent for acid mists. A cooperative study by
19
-------
Manufacturing Chemists* Association, Inc., and PHS on acid mist
emissions reported controlled emission factors from several types of
collectors. They ranged from 0 to .50 Ib. per ton of P^C" produced. The
emission factor multiplier is 3,780,000 tons of phosphoric acid expressed
as 100 perc ei" F. ;•. .
•c ^
4. Phosphate Fertilizers - General
Phosphates along with the nitrates, urea and sulfates are
usually manufactured together in a fertilizer complex and blended to make
the basic grades. Although a great deal of information is available on
fertilizer production, production processes and plant operation, infor-
mation on quantities of each fertilizer processed through each unit
operation and emissions and control levels are relatively limited and at
times contradictory. The major phosphate fertilizer products (DAP, nor-
mal superphosphate and triple superphosphate) have common operations
which generate significant quantities of P?0,- as dust. These include
materials handling, product screening, bagging, and bulk loading. Ferti-
lizer processes to which rock is added directly, such as normal and triple
superphosphate, also have emission from rock pulverization. Control
equipment in the various phases include baghouses, electrostatic preeipi-
tators, and wet scrubbers.
Emission factors of 6 Ib. per ton for rock pulverizing and
2 Ib, per ton for material handling were used. * The same refer-
ences indicated an average control efficiency of 80 percent for rock pul-
verizing. The total quantity processed is the sum of the phosphate rock
that went into the production of normal and triple superphosphate.
Solid fertilizer manufacture generally includes & screening process which
provides for product uniformity. Although little information is avail-
able on emission factors for screening operations, a general factor of
2 Ib. per ton presented by EPA for screening of rock-handling pro-
cesses is assumed. Controls were assumed to be the same as for the
adjacent drying and/or cooling operations.
About 50 percent of the fertilizers are bagged and the
operation has a controlled emission factor of 1 Ib. per ton. The rest
20
-------
is shipped in bulk quantity. It is assumed that the emission factor
for bulk loading will be less than that for bagging operations.
The following sections describe the manufacturing pro-
cesses, the particulate emission sources, emission factors anJ type and
efficiencies of control equipment of each of the three maior fertilizers.
a. Normal Superphosphate
Normal superphosphate (16 to 22 percent P«0..) is pro-
duced by the den process. Phosphate rock is ground to about 90 percent
through 100-mesh screens, and weighed amounts of sulfuric acid and rock
are mixed for 1 to 3 minutes in a pan mixer which is fitted with plows
which rotate at several rpm. Before the material sets, the soupy mass is
discharged into a den below the- pan to further react. Batch operations
were recently being used by over 75 percent of all U.S. plants-^'^
After the curing period, three alternatives are avail-
(10)
able. The product can be ground, dried and bagged for sale; sold
directly as run-of-pile product; or ammoniated-granulated as a component
in mixed fertilizers. Steam or water is used to aid granulation. The
mixture is then dried in a rotary drier, cooled, and conveyed to storage
bins for bagging or bulk sale.
Emission factors and control efficiencies for grind-
ing, drying and cooling operations were obtained. Because of the
varied nature of fertilizer operations, these processes are not always
performed on all normal superphosphates produced. However, it is
assumed that they are performed on all the 1,366,000 tons of normal
superphosphate (as P2^0 Pr°duced.
b. Triple Superphosphate
Commercially, there is little difference between the
manufacture of triple and normal superphosphate. Instead of sulfuric
acid, phosphoric acid is used for acidulation, and its strength depends
on whether the triple superphosphate is to be artificially dried or not.
A strength of 70 to 78 percent H-PO, may be used if it is dried. After
21
-------
the last setting step the product is crushed, dried and cooled. Like
the normal superphosphate it can be granulated to improve the storage
and handling properties of the material, sold directly as run-of-pile or
ammoniated and granulated,
Emissions occur from the same operations £3 ici the
normal superphosphate. Once again it is assumed that all the triple
superphosphate produced undergoes the three operations of grinding, dry-
ing and cooling.
c. Ammonium Phosphates
Much larger quantities of diammonium phosphates (DAP)
are produced than mono -ammonium phosphates. DAP has also been signifi-
cantly replacing normal and triple superphosphate production.
In producing mono and diammonium phosphates, anhydrous
ammonia is passed directly into phosphoric acid to produce either mono or
diammonium phosphate. The material is then dried and cooled prior to
screening. It is also possible to produce ammonium superphosphates by
awmoniating either the normal or triple superphosphate and then using the
same drying, cooling and screening steps as discussed above.
Particulate emissions in addition to those included
under the general category are primarily from the atnmoniator-granulator,
dryer and cooler. Emission factors were available for all three. EPA
reported factors of 2 Ib/ton for an ammoniator-granulator, while NEDS
reported 100 and 69 Ib/ton for a similar process. An intermediate value
of 30 Ib/ton is used here. EPA reported 80 Ib/ton for a combined dryer-
cooler unit. Calculations for an ammonium phosphate cooler, to which
GCA had access, showed an uncontrolled emission factor of 25 Ib/ton of
product and a control level of 80 percent. NEDS indicated from 2.0 to
(14)
48 Ib/ton for cooling. An intermediate value of 25 Ib/ton is used
here as being representative of a typical cooling operation. Based on
the EPA value for a combined dryer-cooler unit, this leaves 55 Ib/ton
as an estimated emission factor for drying alone.
22
-------
The quantity of ammonium phosphates produce-i *re cur-
rently unknown due to the unknown totals manufactured from the ammonia-
tion of normal and triple superphosphates. However, the total quanti-
ties of ammonium phosphates are estimated to be somewhat less than twice
the amount of DAP produced. Using a multiplier of 2, total ammonium and
diammonium phosphates produced (as P^Oj.) are estimated at ?,f>nO 000 tons.
Control efficiencies have been estimated at 80 to 90 per-.. ."». •>: • Av
/Q 1 ("^ »
ammoniator-granulator, drying and cooling operations. * An average
85 percent is used in Table 1.
5. Fertilizer Application
The operation involves receiving the product in bags or
bulk quantities and spreading it in the field. Both liquid and granu-
lated fertilizers of different grades are used. Most of the granulated
material is in particles from 1 mm to 4 mm in diameter. When the ferti-
lizer is spread, however, many finer particles including those produced
by abrasion will enter the atmosphere. The activity of the operation
is more intensive than the bulk material handling problems encountered
in the fertilizer industry. Emission factors of 1 Ib/ton for bulk hand-
ling, bagging, loading and 4 Ib/ton for spreading are assumed. Control
levels of 50 and 0 percent are used. From these assumptions, the hand-
ling and spreading of fertilizer expressed as 100 percent P?0,- is esti-
mated to emit 14,600 tons of P/jO,. into the atmosphere.
Because the quantity of phosphate rock (0.03 million
tons) directly applied to the soil is relatively small compared to en-
riched and mixed fertilizers, the total controlled emissions from
bagging-bulk loading and field spreading are negligible.
6. Elemental Phosphorus
An electric arc furnace is employed to manufacture ele-
mental phosphorus. A total of 6,460,000 tons of phosphate rock was pro-
cessed. The phosphate rock feed, before entering the furnace, must
have adequate porosity so that the gases can escape from the reaction
zone near the furnace bottom. Briquetting, sintering, and nodulizing
23
-------
are common methods of attaining the desired porosity. Before these op-
erations, there are emissions from ore handling and grinding operations.
The general emission factor of 2 Ib/ton was used for ore handling. Al-
though no emission data was available for grinding, a factor of 20 lb/
ton is assumed sir«il*?r to that discussed in phosphate rock processing.
The estimated uncontrolled PO^C; emissions are 16,200 tons for grinding.
With a cyclone scrubber system having an efficiency of 97 percent, the
controlled emissions are approximately 500 tons.
In the sintering operation, phosphate, sand fines, and
coal are blended together and deposited onto moving grates. The mixture
then passes over an oil- or gas-fired ignitor where the coal in the bed
is set on fire. Both updraft and downdraft sintering machines are util-
ized, creating sufficient heat to fuse the phosphatic material. The re-
sulting sinter is then crushed and screened with undersized particles
recycled. In the nodulizing process, the phosphate fines are heated to
incipient fusion in a rotary kiln. The tumbling action in the kiln
causes the material to cohere and form spheroidal agglomerates. Bri-
quetting entails mixing phosphate fines and sufficient water to form a
damp lump of mass. The briquette is then either dried or calcined to
lower the moisture content. These processes are significant generators
of P^Oj. emissions. Scrubbers are often employed to reduce fluoride and
particulate emissions.
Process information from two large phosphorus plants
(million tons per year size) provided emission factors for several
sources. In briquetting, a calciner-cooler system was employed with
a 65 to 85 percent control efficiency for the calciner and 0 percent
control efficiency for the cooler. Based on these data, an emission
factor of 1.3 pounds of P~0,. per ton of rock, before control, was calcu-
lated.
The other plant employed nodulizing with a cyclone-scrubber
system. A controlled emission factor of 0.27 pound of total particulates
per ton of rock was calculated for this plant. Assuming a control effi-
ciency of 90 percent or greater, the emission factor is of the same
24
-------
order of magnitude as the plant discussed above. For this reason the
emission factor of 1.3 Ib. P^CL per ton of rock processed was selected.
Two general sources of PoO,. emissions result from furnace
operation. There is a problem in preventing P^CL fumes from leaking out
of the furnace around the electrodes and feed bins. The other source of
emissions from the furnace is the tapping operation. Since visible
quantities of PoO,. fumes can result during tapping, many companies are
presently installing hoods and ventilation systems to capture the fumes
and pass them through high energy scrubbers. A typical phosphorus plant
with such a vent system and processing 1.5 million TPY of phosphate
rock, had an uncontrolled emission factor of 1.0 Ib. of P_0,./ton of rock
and employed a scrubber with a 90 percent control efficiency. ' The
furnace operates at 1300 to 1400 C. The hot gases given off by the fur-
nace are comprised of phosphorus and CO gases. After passing through a
condenser to recover the phosphorus metal, the exit gas still contains
some phosphorus and about 90 percent CO. This gas is often used as a
fuel for the sintering operation, while any excess gas, typically 5 per-
cent, is generally vented and flared. Consequently, the flarThg~~emis-
/Q 1 r\
sion factors for three plants^ ' ' were 0.2, 2.0 and 3.1 Ib. of P 0 /
ton of rock. Using an average emission factor of 1.8 Ib. P~0r per ton
of feed, uncontrolled emissions were estimated at 5,800 tons per year.
No controls are generally applied to flaring operations.
Other PjOc emissions are from the handling of collected
dusts from air pollution control devices and from the storage and trans-
fer of phosphorus in the condenser. The cpllected dust is discharged
dry, then usually mixed with water and reprocessed. ' Since these
operations are infrequent and the total quantities are relatively small,
the total emissions are estimated to be negligible.
7. Thermal Process Phosphoric Acid
This acid is produced from elemental phosphorus in two
ways depending upon whether the phosphorus is condensed or not. The
"two step" method using the condenser is now more common. The elemental
25
-------
phosphorus is burned at 1700 to 2800 C using air as tha oxygen source.
The combustion product is subsequently hydrated and cooled in the
hydrator-absorber with dilute phosphoric acid or water. This produces
phosphoric acid above 50 percent in strength, Superphosphoric acid
usually el :; ;,u;•.•&-!' greater than 70 percent H»PO, can be trade by limit-
(3 11)
ing the amount of water added.
Phosphoric acid mist is a pollutant in the hydrator and
absorber tail gas. All plants are equipped with some type of acid
mist collection system. Some mist does escape, however, and of this,
at least 50 percent of the particles are less than 1.6u in size. EPA's
Compilation of Emission Factors presents the following cor'r.-lled emission
f actors :
packed tower 4.6 Ib. of mist/ton of acid
Venturi scrubber 5.6 Ib. of mist/ton of acid
glass-fiber mist eliminator 3.0 Ib. of mist/ton of acid
wire mesh mist eliminator 3.7 Ib. of mist/ton of acid
high pressure-drop mist n „ .. . . ^ , . .,
.. . . 0.2 Ib. of mist/ton of acid
eliminator
electrostatic precipitator 1.8 Ib. of mist/ton of acid
Efficiencies for these types of control equipment are well above 90
percent.
Process descriptions by J.C. Barber made it possible
to derive and compare the emission factors. Burning phosporus at a
rate of 3 tons/hour with a venturi scrubber and single mist eliminator
unit having 99.9 percent recovery resulted in controlled emissions of
5-10 Ib. of P?Q,-/hour. This gives an emission factor of 0.75 - 1.5
Ibs. mist per ton of acid. Calculated factors using another data
source were .26-4.3 Ib. P70,./ton P<«0_. Using an average controlled
emission factor of 2.6 Ibs. P«0,/ton acid as P~0,» the annual controlled
emissions are estimated at 1,600 tons.
8. Sodium Phosphates
The major marketable compounds are: trisodium phosphate,
sodium metaphosphate, tetrasodium pyrophosphate and sodium
26
-------
trlpolyphosphate. The manufacture of these chemicals involves a reaction in
a tank, and the separation of the solid, steps which have no emissions. The
subsequent operations, calcining or drying, cooling, grinding and bagging,
are estimated as typical emission sources of the phosphate industry.^ '
Assuming the emission factors and control efficiencies
to be the same as the similar operations previously discussed, the
relatively important emissions are from dry-cooling and calcining-
cooling operations. An estimated 60 Ib/ton and 90 percent control
efficiency were assumed for both, based on available information from
other processes. Annual production figures for various sodium phos-
phates, were calculated to have a PjOc content of 800,000 tons,
9. Soaps and Detergents
The sodium phosphates are used in soaps, detergents and
boiler water treatment as softening agents. By removing calcium and
magnesium compounds, scale deposits are avoided in boiler tubes and
sticky precipitates are avoided in wash water. Since the operations
are wet, it is estimated that emissions are negligible. The soap and
detergent manufacturers receive large quantities of sodium phosphates
which are used in soaps and detergents. Receiving and handling appears
to generate insignificant levels of P^Oc emissions since the product is
received in bags. The mixing operation seems to be the only source.
An emission factor of 2 percent and control efficiencies of 98 percent
are estimated, based on factors for processes believed to be similar.
An estimated 580,000 tons of ?,(),. went into soaps. " '
10. Calcium Phosphates
Calcium phosphate production is estimated to be
200,000 tons per year. ' ' It is produced by two different reac-
tions. The first involves the reaction of P?0, gas passing through a
column of phosphate rock. This produces molten calcium metaphosphate,
which is collected in a pool, tapped, solidified by quenching or air-
cooling, ground and bagged. The second involves the reaction of phos-
phoric acid and lime. The product is dried and then also ground and
bagged.
27
-------
Likely emission sources are drying and cooling, grinding,
bagging, and material handling. Emissions from material handling are
again generated when calcium phosphates are consumed in animal feeding.
Emission factors for these operations have already
appeared in the discussion of other products. The drying or cooling
operation with emission factors ranging from 15-105 Ibs. per ton (60
Ib/ton ave.) generates the only significant emissions. Assuming a 90
percent control efficiency the controlled emissions are 600 tons per
year.
11. Plating, Polishing and Miscellaneous
There are four important applications in plating and
polishing metal surfaces: (1) phosphating or forming a protective
layer of insoluble phosphate salt; (2) polishing and brightening the
metal surfaces in phosphoric acid baths; (3) electropolishing in phos-
phoric acid baths; and (4) chemical plating a nickel phosphorus alloy
on various surfaces. Approximately 250,000 tons of P-O- are con-
sumed for these applications. These operations emit phosphoric acid
mist into the atmosphere. Process information to allow formulation of
emission factors and types of control is not readily available, but
since the emission of mist is similar to the production of phosphoric
acid by the wet process, the controlled emission factor is assumed not
to exceed 0.25 Ib per ton of acid.
Phosphorus is a base of many end products. Many com-
pounds are made such as red phosphorus for matches, phosphorus chloride
for organic synthesis, insecticides and plasticizers, phosphorus cop-
per, zinc phosphide, phosphorus sulfide for matches and lubricants, and
phosphorus oxides for dehydrating agents. Each transformation is
estimated to generate insignificant levels of emissions relative to
others already discussed partly because of the small quantities of
products made.
28
-------
12. Inady e rt ent Sourceg
In addition to the sources from mined phosphates and
their subsequent uses, there are other phosphorus emission sources.
These include incineration of refuse, the production of large quan-
tities of iron, steel, and cement, and the combustion of residual oils
and coal.
a. Refuse Incineration
Total uncontrolled particulate emissions from refuse
incineration (circa 500 C) were estimated in a "Systems Study of Air
/I Q\
Pollution from Municipal Incineration1 to be 150,000 tons per year.
Elsewhere, a slightly higher figure was estimated, using the emission
factor of 30 Ib per tpn^ ' with a national figure of 18,000,000
tons ' per year of refuse incinerated. From an analysis of refuse
categories, a weighted average phosphorus content was calculated to be
0.23 percent P00C f.05% P x (4.58 Ib of P»0, per Ib of P)l . With an
(18)
estimated 37 percent efficiency, and an average uncontrolled
emission of 250 tons of P50_, the total controlled emission was
160
tons of P2°5*
b. Iron and Steel Industries
?„()(. is emitted in trace quantities in the iron and
steel industry, where large quantities of particulates are emitted
from the various types of furnaces (circa 1500 C). One analysis of
the composition of fumes from an open-hearth furnace gave .5 percent
P90,.. A second analysis from an electric-arc furnace contained
(20)
.2 percent P9Q,-' Another analysis from a 15 ton electric-arc steel
(17)
furnace showed that the dust contained ,4 percent P90_. An average
0.35 percent P90- content is assumed for all emissions. These sources
do not state the methods of analysis, nor the number of samples
analyzed which was probably one sample in all cases. Emission factors
from a blast furnace are 150 Ib/ton and a weighted average for other
furnaces in the steel industry is 25 Ib/ton. Total production was
245 million tons of iron and 145 million tons of steel.
29
-------
Controls Include a primary cleaner (usually a
settling chamber as cyclone) and often a secondary unit connected in
series (either a scrubber or electrostatic precipltator). Control
efficiencies are estimated at around 90 percent. the controlled
emissions are therefore 6400 TPY for iron and 600 TPY for steel manu-
facturing.
c. Cement
The cement Industry also emits large quantities of
materials. With a control level of 88 percent, controlled total par-
ticulate emissions from the production of cement have been estimated
at 934,000 tons/yr. ' The concentration of P-O, in the particulate
emissions was not found In the literature and is estimated at .04 per-
(21)
cent, equal to the P_0,. content of average limestone. '
d. Oil Burning
Heavy residual oil contains trace quantities of
P2°<:' An elemental analysis of total participates in the flyash from
its combustion showed in one test that phosphorus (as P?0,) amounted
to 0.9 percent of total solids collected in a laboratory precipltator
at 230 F. Total dust emissions from all types of oil burning are
estimated at 287,000 tons/yr. ' These emissions were almost com-
pletely uncontrolled in 1970.
e. Coal
Such large quantities of coal are burned in the
U.S. that trace quantities of phosphorus in the emissions make this
source significant. Total uncontrolled particulate emissions from
the burning of coal is on the order of 33,800,000 tons per year with
a weighted control efficiency of 82 percent. ^ Colorlmetric analysis
of the ash from 373 samoferf"^fNcoaTvtaken from across the U.S.
Indicated an averag^/pliQaphortis contest of 0.074 percent, equivalent
to a P20c content/yf 0.34^fr%rcent. 7 This results in an estimated
emission of 20|J<*0 edlSr3ji=s£lt5l ^fter control. Thus, coal burning is
one of the largerBougce3~"tx!entlf led in this study.
30
-------
Emissions from the mining and cleaning of coal are
negligible in comparison to the combustion of coal.
C. SUMMARY OP PRINCIPAL EMISSIONS
Table 3 summarizes the largest 1970 emissions of phosphorus
as the estimates are developed in Table 2. In summarizing, emissions
from individual operations are combined within plants of a given type.
Also, emissions estimated under the heading "Fertilizer - General" in
Table 2 are distributed among the three specific types of fertilizers in
proportion to the P^O,. produced in each of the three classes.
Table 3 groups the emissions in two categories, those directly
associated with the phosphorus or phosphorus materials industry; and
those having little to do with the phosphorus industry called inadvertent
sources. The latter category contributes about 17 percent of total U.S.
emissions. The principal sources listed in Table 3 are examined in
further detail in later sections of this report.
31
-------
TABLE 3
PRINCIPAL SOURCES OF PHOSPHORUS-CONTAINING EMISSIONS - 1970
Phosphorus Indus try
Triple superphosphate
Ammonium phosphate
Normal superphosphate
Fertilizer application
Rock process itig
Elemental phosphorus
Inadvertent Sources
Coal combustion
Iron manufacturing
U.S. EMISSION (TPY P,,0_)
• "*- i" jr
35,700
30,700
15,600
14,600
12,000
9,900
20,700
6,400
% OF U.S.
22.3
19.2
9.7
9.1
7.5
6.2
12.9
4.0
90.9
32
-------
IV, REGIONAL DISTRIBUTION OF...PRINCIPAL SOURCES AND EMISSIONS
For purpose of showing geographical distribution, the U.S. was
divided into ten regions identical to the Regional Branches of EPA:
States
Connecticut, Maine, Massachusetts, New Hampshire, Rhode
Island, Vermont
II New Jersey, New York, Puerto Rico, Virgin Islands
III Delaware, Michigan, Pennsylvania, Virginia, West Virginia,
District of Columbia
IV Alabama, Florida, Georgia, Kentucky, Mississippi, North
Carolina, South Carolina, Tennessee
V Illnois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
VI Arkansas, Louisiana, New Mexico, Oklahoma, Texas
VII Iowa, Kansas, Missouri, Nebraska
VIII Colorado, Montana, North Dakota, South Dakota, Utah,
Wyoming
IX Arizona, California, Nevada, Hawaii and the South
Pacific
X Alaska, Idaho, Oregon, Washington.
Emissions from the principal sources listed in Table 3 are
listed among these ten regions, as shown in Table 4. Also, the number
of plants producing the emissions are shown in the table when such
information was available.
The accuracy of the distributions by region varies with the
category. The number of plants per category ranged from one to several
thousand in this study. When the number of plants was less than 100,
an attempt was made to identify each plant and plant location, and
include it in one of the ten regions. When production or capacity
figures for these plants were available, total production or capacity
for each region was computed, and the U.S. emission estimate for that
category was distributed by region accordingly. When production or
capacity figures were not available, the emission was distributed by
the number of plants in each region. If the number of plants was very
33
-------
TABLE 4
REGIONAL DISTRIBUTION OF PRINCIPAL SOURCES AND EMISSIONS
PRINCIPAL SOURCES
Phosphorus Industry
Triple Supet phos ."
Fei l il izet Distril».
Ruck Piui-fibiug
Elemental Phosphorus
Inadvertent Sources
lion Manufaclur ing ~
TOTAI
1
1
0
0
0
0
0
0
.1
0.7
0
0
0
0
a
0
0
r °'2
^ 0.1
2
0
0
0
0
0
0
.3
1.9
0
0
0
0
1.2
i.?
.4
5
1.9
1.2
3
0
0
0
0
0
0
.4
3.0
0
0
0
0
4,5
21.8
1.8
19
6.7
4.2
4
33.1
11
15.5
12
13.0
15
1.6
11. 0
10.5
23
5.8
9
4,4
21.1
.5
7
84.0
52.7
5
0
0
.1
1
0
0
5.1
34.8
0
0
0
0
i,5
41,3
3.1
30
16.8
10.5
6
0
0
9.2
8
1.8
2
1.2
8.5
0
0
.1
1
.3
1.4
.3
2
12.9
8.0
7
0
0
2.5
2
0
0
4.0
27.5
0
0
0
0
.8
4.1
0
0
7.3
4.6
8
.8
1
.7
1
.8
1
.8
5.4
.7
7
. 4
1
.7
5.3
.2
2
5.1
3.2
9
0
0
1 .3
7
0
0
.5
3.2
.1
1
0
0
.1
0.7
.1
1
2.1
1.3
10
1.8
1
1,4
2
0
0
.6
4.3
.7
7
3.6
3
.1
' 0.3
0
0
8.2
5.1
TOTAL (units)
35.7 OO3 TPY)
13 (Plants)
30.7 (H)3 TPYl
33 (Plants)
15.6 (103 TPY)
18 (Plants)
14.6 (103 TPY)
100 {"/„ Bulk Plants)
12.0 (103 TPY)
38 (Plants)
9.9 (103 TPY)
14 (Plants)
20.7 dO^TFYl
100 (7. shipments)
6.4 (103 TPY)
66 (So. Plants)
145.6 (103 TPY)
90.9 % of U.S. Total
REF.
24
24
25
26
27
26
2 *
28
-------
small or there was reason to believe that certain plants were larger or
produced more emission, distributions were weighted accordingly.
On the other hand, when the estimated number of plants was
greater than 100, and the distribution of plants was not known, the
regional breakdown was made on a different basis, such as population,
geographical area, or shipments reported; whichever seemed to be most
appropriate for that category. Whether the distribution was by plant
size, number of plants, or another statistic, the distribution is
believed to be accurate to within 10 percent in most cases.
Specifically, emissions from the production of triple superphos-
phate and ammonium phosphate fertilizers were distributed by plant
(24)
capacity as a percent of total U.S. capacity. In the case of nor-
mal superphosphate, since plant capacities were unavailable, distribu-
(25)
tion was made by number of plants per region.
REGION
Triple superphosphate
Capacity*
No. of Plants
Ammonium Phosphates
Capacity*
No. of Plants
1
0
0
0
0
2
0
0
0
0
3
0
0
0
0
4
1633
11
1423
12
5
0
0
10
1
6
0
0
826
8
7
0
0
225
2
8
41
1
56
1
9
0
0
120
7
10
89
1
127
2
U.S.
TOTAL
1763
13
2787
33
* (1,000's TPY P2°5^
Emissions due to the mixing, bagging, and soil application of ferti-
lizers were distributed by the estimated numbers of bulk blend plants
in each region, on a percentage basis. A U.S. total of 3,153 plants
/•«[ £ \
were estimated in 1966.
Distribution of emissions from rock processing was calculated
using the reported capacity of 38 plants engaged in mining activities.
(27)
It was assumed that processing operations were located near the mines.
Distribution of emissions from production of elemental phosphorus was
also by reported capacity.
35
-------
Rock processing
Capacity (106 TPY)
No. of Plants
Elemental Phosphorus
Capacity (1Q3 TPY)
No. of Plants
*
estimate
I
0
0
0
0
2.
0
0
0
0
3
0
0
0
0
4
44.7
23
447
9
1
0
0
0
0
REGION
_6 I 8_ 9
0 0 2.6 0.3
007 1
10* 0 30 0
101 0
10
2.9
7
274
3
TOTAL
50.
38
761
14
8
The two sources classed as "inadvertent" were distributed as
follows. Emissions from the combustion of coal were distributed by
tonnage of coal shipped, by state of destination, on a percentage
basis. Emissions irom the production of iron were distributed by the
amount of iron and steel scrap and pig iron consumed in each state,
making estimates where data had been withheld. The number of plants
t'") K\
operating blast furnaces in 1970 was reported to be 66:
1 2
0 5.5
3
25.4
REGION
456
7.0 44.4 4.5
7 8
0 3.4
9 10
1,7 0
TOTAL
92.2
Metal consumed
(106 TPY)
No. of Plants 0 5 19 7 30 2 0 2 1 0 66
As a result of these assumptions, the principal emission sources
are distributed most heavily in Region 4, where an estimated 84,400 TPY
of P-jO,. is released into the atmosphere. This is about 53 percent of
the U.S. total emission, and is the result of concentrated phosphate
operations of several kinds, especially in the states of Florida and
Tennessee. Region 4 is also the region with the greatest emission per
unit geographical area, having an estimated 0.22 tons of P^O,. per square
mile-year.
36
-------
V.
NATURE OF EMISSIONS
Emissions of particulate containing phosphorus depend both on
the conditions of the emitting process, and on the characteristics of
the element phosphorus and its compounds. From the chemist's viewpoint,
phosphorus is located in the periodic table between nitrogen and
arsenic and is not considered a metal. Phosphorus is similar to nitro-
gen in some respects, forming numerous compounds ranging from the
simple to the complex. These range from the phosphates essential in
metabolism, to other compounds which are extremely toxic such as phos-
phine (PH~) and halogenated compounds including phosphorus pentabro-
mide (PBrs), pentachloride (PCI-) and pentaf luoride (PF,.).
Table 5 lists some of the principal physical properties of
phosphorus.
TABLE 5
PHYSICAL PROPERTIES OF PHOSPHORUS
Melting point:
Boiling (vaporization) point:
Density:
Atomic weight:
Heat of vaporization:
Valence (oxidation states):
44°C
280°C (B. Pt. of P203 = 174°C)
1.82 g/cm3
31.0 a.w.u.
3.0 kg-cal/g atom
+5, -3, and +3 commonly, and all
states from +5 to -3 occasionally
The properties that are most pertinent to this study includes
the ability of phosphorus to form many kinds of compounds, due to its
numerous possible oxidation states; the tendency of its oxides (phos-
phorus oxide, P?0_ or P,0,J and phosphoric oxide or pentoxide, P20r
or P,0,n) to react rather quickly with water vapor to form phosphoric
acid, H~PO,; and the vaporization temperature which is low when com-
pared to many of the processes used in the industry.
Ref. 29, Table 3-160
37
-------
A. FERTILIZER EMISSIONS
Particles emitted from fertilizer processes range from finely
divided rock to finished fertilizer. Rock particles tend to be large
and thus tend to settle near the emission point, although a small quan-
tity of subtnicrometer dust from drilling and crushing may be expected to
travel distances on the order of miles before deposition. Rock par-
ticles contain tricalciutn phosphate, in concentrations ranging from 15
to 80 percent equivalent weight of P,jO « This phosphate is stable and
insoluble until reacted.
The fertilizer product superphosphate, both normal and
triple, is monocalcium phosphate which Is stable and partially soluble.
Particles of normal superphosphate also contain gypsum. They occasion-
ally contain dicalcium phosphate which is also partially soluble.
Triple superphosphate is non-hygroscopic. Anmonium and diammonium
phosphates are stable, white powders and are soluble in water.
Particle sizes in fertilizer emissions are not well described
in the literature. It was reported that 12 percent (by weight) of the
emission from a superphosphate dryer consisted of particles of less
than 10 micrometers in diameter. These particles were described as
hot, moist, partially water soluble, corrosive, odorous, and able to
adhere to almost any surface. Other fume particles of ammonium chloride,
and fluoride-containing particles are also emitted.
B. ELEMENTARY PHOSPHORUS EMISSIONS
Electric furnace emissions include, in addition to phos-
phorus vapor, possible variable quantities of lime, silica, alumina,
and magnesia particulate. The furnace temperature is 1300 to 1400 C,
at which temperature the vapor is believed to be in the form P.. When
it cools to 800°C and below, at least part of the vapor becomes P?.
Most of the vapor is trapped under water by hot water
sprays, in which it condenses to the liquid "metal". Vapor that
escapes and reacts quickly with oxygen to form P^O,. which changes
quickly to acid, H«PO/ in the presence of moisture. P^O- is extremely
~J 4" Mm J
38
-------
hygroscopic. The other oxide, P90» which forms in limited oxygen con-
& ,3
centrations, also quickly becomes phosphoric acid. Therefore it appears
from basic chemistry that most of the phosphorus emission is in very
fine droplets of phosphoric acid. These are probably hygroscopic, and
grow slowly as they travel, until gravitation or other natural pro-
cesses remove them from the atmosphere.
Condensed phosphorus is described as a yellow, wax-
like solid (below 44 C) which ignites spontaneously in air, forming
oxides. This is the reason for keeping it under water. Steatn vapors
from the surface of the water, although possessing a repelling odor,
may include extremely low concentrations of dilute phosphoric acid.
"White" phosphorus is P, vapor; and "red" phosphorus is
thought to be the same molecule joined in chains. In the proper atmos-
phere these are fairly stable, but otherwise they are reactive and
poisonous. Although the emissions from the production of phosphorus
contain these materials, they probably very quickly become acid on
exposure to air.
C. PHOSPHORIC ACID PLANT EMISSIONS
described;
Particulate emissions from a thermal acid plant have been
(30)
2 percent less than 0.5 micrometer in diameter
30 percent less than 1 micrometer in diameter
85 percent less than 2 micrometers in diameter
99 percent less than 3 micrometers in diameter
3
Particle densities are 1.57 to 1.68 g/cm , indicating high acid con-
tent, and are described as corrosive and irritating.
Combustion of phosphorus in thermal acid manufacture is at
1700 to 2800 C. Presumably all of the phosphorus is sufficiently
oxidized and then hydrated to acid, so that no toxic emissions result.
D. OTHER SOURCES
Under certain conditions, heating phosphorus to high
temperatures in the presence of halogens can result in the formation of
39
-------
(3D
toxic compounds such as phosphorus chloride. This in turn reacts
with water to form PH, (phosphine gas) which is highly toxic. Phos-
phine has been used in the fumigation of wheat, with some toxic effects
(32)
to workers. The emission of these toxic compounds from the pro-
duction of phosphoric acid has not been reported, but is cited
here as an apparent possibility.
A large number of phosphorus compounds are made specifically
for their toxic or poisonous properties, for fumigation, insecticides,
etc. While the small quantity of these compounds has precluded them
from this report, their contribution to the emission of toxic phos-
phorus compounds may be significant.
A dye called phosphine contains no phosphorus; also, note that the
poisonous gas phosgene contains no phosphorus.
40
-------
VI. UPDATING OF EMISSIONS ESTIMATES
The following recommendations are made for periodically updating the
estimates made in this study:
A. VERIFICATION OF CURRENT ESTIMATES
1. Although phosphate fertilizer manufacture is the largest
source of P^O,. emissions, very little data exists for accurately deter-
mining emissions levels and degree of control from this source category.
The emissions and control values presented for this source category warrant
further verification, although the general conclusion regarding the
magnitude of the emissions from this source category, we feel, is valid.
2. Verify the high levels of control indicated for phosphate
rock processing as the category generates a significant quantity of
emissions before control.
3. PO^C emissions from normal superphosphate manufacture
were distributed within geographic regions by the number of plants since
plant capacities were unavailable. Such capacities should be obtained
and the geographic distribution verified.
B. PERIODIC REVIEW OF ESTIMATES
1. The Bureau of Mines estimates for material flow, industry
practices, and trends, provide the best estimates of the size of the
industry.
2. EPA activities are currently generating the best emissions
data and should be reviewed using:
a. Overall industry studies, e.g. references (6)(27).
b. The Source Test Program in which specific
individual plant emissions are measured.
This information provides emission factors
for specific examples of typical industrial
operations, and also provides some analyses
of the particulate, usually including trace
metal content and particle size.
41
-------
c. NEDS (National Emissions Data System) is
steadily being enlarged and improved. This
system can provide emission factors for
specific plants and plant operations, the
type of particulate control equipment in
use, and the actual, or estimated, control
efficiency. The system may eventually be
expanded to include a description of the
emissions.
3. The phosphorus industry should be consulted for its
opinion and suggestions on the most recently published estimates. This
may be best accomplished by interviewing the Phosphorus Commodity
Specialist, Division of Non-ferrous Metals, Bureau of Mines in Washington;
or by interviewing one or more of the principal companies in the industry.
4. The literature should be reviewed, using (a) industrial
views as published from time to time in Chemica1 Engineering, for example,
and (b) environmental views as summarized in Pollution Abstracts, for
example.
5. Individual companies or plants may be approached for
opinions, data, or cooperative tests of their own operations. It is
difficult to obtain fresh information in this way, due to the natural
reluctance of plants to discuss environmental problems. However, data
thus obtained have a relatively high degree of reliability.
6. State agencies in which specific plants are located may be
able to provide useful information, and should be contacted.
42
-------
VII. REFERENCES
1. Minerals Yearbook, Bureau of Mines, U.S. Govt. Printing Office,
Washington, B.C. (1970).
2. The Phosphate Industryinthe Southeastern U.S. and its Relation-
shipto World Mineral Fertilizer Demand, U.S. Bureau of Mines,
Washington, D.C." (1570)".
3. Stephenson, Richard M., Introduction to ChemicalProcess Industries,
Reinhold Publishing Corp., N.Y. (1966), pp. 156-172.
4. Hignett, T.P. et al., "Elemental Phosphorus in Fertilizer Manu-
facture", ChemicaL Eng. Progress, 85-91 (May 1967).
5. Mineral Facts andProblems,Bureau of Mines, U.S. Govt, Printing
Office, Washington, D.C. (1970)
6. AtmosphericEmissions from Thermal-Process PhosphoricAcid, U.S.
HEW, NAPCA Publ. No. AP-48, Durham, N.C. (Oct. 1968).
7. Statistical Abstract of the United States: 1970, U.S. Bureau of
the Census (92nd edition), Washington, D.C. (1971).
8. Waggaman, William H., Phosphoric Acid, Phosphates and phosphatic
Fertilizers, Reinhold Pubi. Corp., N.Y. (1952).
9. Personal communication with members of the Phosphorus or Phosphorus
materials industries.
10. Vandegrift, A.E. et al., Particulate Pollutant System Study, Vol.
Ill, Handbook of Emission Properties, EPA Contract No. CPA 22-69-
104.
11. Compilation of Air Pollutant Emission Factors, U.S. EPA, Office
of Air Programs, Triangle Park, N.C., Publ. No. AP-42.
12. Source Tests of specific plants and operations, performed by EPA;
partial reports furnished by EPA to supplement literature infor-
mation.
13. Atmospheric Emissionsfrom Wet-Process Phosphoric Acid Manufac-
ture , U.S. Dept. HEW, NAPCA Publ. No. AP-57 (April 1970).
14. NEDS (National Emissions Data System) information, furnished by
EPA to supplement literature information.
15. GCA File - 1970 - Data from industrial plants used to prepare
Implementation Plans.
43
-------
16. Barber, J.C., "The Cost of Air Pollution Control, Chemical
Engineering Progres s, 78-82 (September 1968).
17. Athanassiadis, Yanis C., Pre1iminary AirPollution Survey of
Phosphorus and -its Compounds, U.S. Dept. of HEW, Raleigh, N.C.,
NAPCA Publ. No. APTD 69-4S.
18. Systems Studyof Air Pollution FromMunicipal Incineration,
Arthur D. Little, Inc., EPA-22-69-23, Cambridge, Mass. (March
1970).
19. Proceedings of 1970 National Incinerator Conference, presented In
Cincinnati, Ohio, May 17-20, 1970, Am. Soc. of Mech. E.
20. Schueneman, Jean J., Air Pollution Aspects of the Iron and Steel
Industry, U.S. Dept. HEW, Cincinnati, Ohio, 51, 61 (June 1963).
21. Chemical Rubber Co., Ohio, Handbook of Chemistry and Physics, 46th
Edn., 1965-66.
22. Smith, W., Emiss ions from Fuel Oil Combust ion, U.S. Dept. HEW,
Public Health Service Publ. No. 999-AP-2.
23. Abernathy, R.F.?e t.al., Major Ash Constituentsin U.S.Coals,
U.S. Bureau of Mines, Report of Investigations No. 7240, 1969.
24. National Fertilizer Development Center, TVA, Muscle Shoals, Ala.,
"Fertilizer Trends - 1971, a biennial publication,
25. Personal communication from Ms O'Toole, Fertilizer Institute,
Washington, B.C., information taken from Fertilizer Index, pub-
lished by the Institute; February, 1973..
26. U.S. Dept. of Interior, Federal Water Pollution Control Admin,,
The Economics of Clean Water, 4 Vols. March, 1970.
27. Battelle Memorial Institute, Richland, Washington, Inorganic
Fertilizer and Phosphate Mining Industries - Water Pollution and
Control, report to EPA, Grant No. 12020FPD, Sept. 1971.
28. American Iron and Steel Institute, "Iron and Steel Producing and
Finishing Works of the U.S.", (a table), Directory of Iron and
Steel Works of the U.S. and Canada, 1970.
29. Perry's Chemical Engineer's Handbook, 4th Edition, McGraw Hill,
New York, 1963.
30. Coykendall, J.W., et. al., "New High Efficiency Mist Collector",
J.A.P.C.A. 18; 5(315), May 1968.
44
-------
31. Slenko, M.J., and Plane, R.A., Chemistry, 2nd Edn., McGraw-Hill,
New York, 1961.
32. Riegel, E., Industrial Chemistry, Reinhold Pub. Co., New York,
1942.
Additional Background References
33. Abernathy, R.P. et al., Rare Elements in Coal, U.S. Bureau of
Mines, Information Circular 8163.
34. Lodwick, J.R., "Chemical Additives in Petroleum Fuels: Some Uses
and Action Mechanisms", J. of the Inst.of Petroleum, Vol. 50,
No. 491 (November 1964).
35. Davenport, J.E. et. al., "Beneficiation of Florida Hard-Rock
Phosphates", Ind\ Eng. Chem. Process Des., 8-4, 533-37 (Oct. 1969).
36. Davenport, J.E. et. al., "Beneficiation of Florida Pebble Phos-
phate Slime, Ind.Eng. Chem. Process Des., 8-4, 533-37 (Oct. 1969).
37. Teller, A.J., "Control of Gaseous Fluoride Emissions", Ch. Eng.
Progress, Vol. 63, No. 3, 75-79 (March 1967).
38. Rushton, W.E., "Isothermal Reactor Improves Phosphoric Acid Wet
Process", Ch. Eng., 80-83 (Feb. 23, 1970).
39. Stem, D.R. et. al., "Processing Problems Pared for Superphosphoric
Acid", Ch. Eng., 99-102 (March 23, 1970).
40. Bostwick, L.E., "Loop System Slashes Costs for Making H»PO,",
Ch. Eng.. 100-103 (April 20, 1970).
41. Bryent, H.S. et. al., "Phosphorus Plant Design, New Trends", Ind.
and Eng. Chem., 8-23 (April 1970).
42. Huffstutler, K.K., "Sources and Quantities of Fluorides Evolved
from the Manufacture of Fertilizer and Related Products", J. of
Air Poll. Control Assoc., 682-84 (December 1966).
43. Sachsel, G.F., "Fume Control in a Fertilizer Plant - A Case
History", J. of APCA, 214-218 (February 1957).
44. Kearns, T.C., "Polyphosphate Fertilizers made via Simplified
Route"» Ch. Eng. 94-96 (December 1969).
45. Environmental Engineering Inc., Gainesville, Florida, Source
Sampling of Air Contaminant Emissions from a Phosphate Fertilizer
Plant, EPA Contract No. CPA-70-82 awarded Jan. 21, 1972.
45
-------
TECHNICAL REPORT DATA
f Please read Inuructions on the reverse before completing)
1, REPORT NO. 2.
EPA-45n/3~74-013
4. TITLE AND SUBTITLE
National Emissions Inventory of Sources and
Emissions of Phosphorus
7. AUTHOR(S)
9, PERFORMING OR"ANIZATION NAME AND ADDRESS
GCA Corporation
GCA Technology Division
Bedford, Massachusetts 01730
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
Research Triangle Park, N. C. 27711
15. SUPPLEMENTARY NOTES
3. RECIPIENT'S ACCESSIOP*NO.
5 REPORT DATE
May 1973
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10, PROGRAM ELEMENT NO.
2AE132
11. CONTRACT/GRANT NO.
68-02-0601
13. TVPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
16 ABSTRACT
A national inventory of the sources and emissions of the element phosphorus
was conducted. All major sources of phosphorus-containing emissions were iden-
tified and their phosphorus emissions into the atmosphere estimated. Also, a
method for updating the results of the study every two years was recommended.
17. KEY WORDS AND DOCUMENT
a. DESCRIPTORS b.lDENTI
Phosphorus
Air Pollution
Emission
Inventories
Sources
13. DISTRIBUTION STATEMENT 19. SECU
Release Unlimited mSECU
EPA Form 2220-1 (0-73)
ANALYSIS
FIERS/QPEN ENDED TERMS c. COSATI I leld/Group
RITY CLASS (This Report) 21. NO. OF PAGES
Jnclassified 45
RITY CLASS (Thispage) 22. PRICE
Jnclassified
46
-------
ENVIRONMENTAL PROTECTION AGENCY
( Tachnical Publication a Branch
• Office of Administration
Research Triangle Park. N.C. 27711
POSTAGE AND FEES PAID
ENVIRONMENTAL PROTECTION AGENCY
EPA - 335
OFFICIAL BUSINESS
AN EQUAL OPPORTUNITY EMPLOYER
Return this sheet if you do NOT wish to receive this material I I,
or if change of address is needed I I. (Indicate change, including
ZIP code.)
------- |