EPA-450/3-80-030
Source Category Survey
Detergent Industry
Emission Standards and Engineering Division
Contract No. 68-02-3059
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Triangle Park, North Carolina 27711
June 1980
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This report has been reviewed by the Emission Standards and Engineering Division
of the Office of Air Quality Planning and Standards, EPA, and approved for publication.
Mention of trade names or commercial products is not intended to constitute endorsement
or recommendation for use. Copies of this report are available through the Library
Services Office (MD-35), U.S. Environmental Protection Agency, Research Triangle
Park, N.C. 27711, or from National Technical Information Services, 5285 Port Royal
Road, Springfield, Virginia 22161.
Publication No. EPA-450/3-80-030
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PREFACE
This revised Source Category Survey Report was prepared by Midwest
Research Institute (MRI) under EPA Contract No. 68-02-3059, Task 7.
The report was prepared by Ms. Linda E. Greer for Mr. James Eddinger,
EPA Lead Engineer.
Approved for:
Midwest Research Institute
'LloycKT. Tayltfr
Director
North Carolina Office
May 29, 1980
iii
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TABLE OF CONTENTS
Page
Preface 11
List of Tables 1v
List of Figures v
1.0 SUMMARY 1
2.0 INTRODUCTION 3
3.0 CONCLUSIONS AND RECOMMENDATIONS 8
3.1 Conclusions 8
3.2 Recommendations 8
4.0 DESCRIPTION OF INDUSTRY 9
4.1 Source Category 9
4.2 Production 13
4.3 Process Description 13
5.0 AIR EMISSIONS 18
5.1 Plant and Process Emissions 18
5.2 Total National Emissions 23
6.0 EMISSION CONTROL SYSTEMS 24
6.1 Control Approaches 24
6.2 "Best Systems" of Emission Reduction 26
7.0 EMISSION DATA 27
7.1 Availability of Data 27
7.2 Sample Collection and Analysis 27
8.0 STATE AND LOCAL EMISSION REGULATIONS 28
9.0 REFERENCES 34
iv
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LIST OF TABLES
Page
2-1 Components of Powdered Laundry Detergent in the
United States 5
4-1 Industry Statistics ..... 10
4-2 Spray-Dry Detergent Manufacturers, 1980 11
5-1 Emission Data 19
5-2 Particulate Emissions From a Typical Spray Dryer 22
8-1 Summary of State Air Pollution Regulations 29
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LIST OF FIGURES
Page
4-1 Production of Powdered Detergent and Soap 14
4-2 Manufacture of Spray-Dried Detergents 15
VI
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1.0 SUMMARY
This Source Category Survey Report presents information gathered on
processes, pollutants, and control equipment associated with the manufacture
of detergent by spray drying. The source category is a subpart of Standard
Industrial Classification (SIC) Code 2841. The production of liquid
detergents, soap, scouring powders, and glycerin and the dry mixing of
powdered detergent were not considered in this report because there was
no evidence of significant emissions from these processes.
There are 33 plants -n 17 states which currently spray-dry detergent.
Numerous additional small plants produce a small amount (less than 5 percent
of the total U.S. detergent production) of powdered detergent by dry
mixing of raw materials.
In 1977, there were 1.5xl06 Mg (1.7xl06 tons) of powdered detergent
produced by spray drying or dry mixing. Average production of spray-dried
detergent was 45,000 Mg/yr (50,000 tons/yr) per plant. Production of
powdered detergent has increased slowly in the past 10 to 15 years and is
projected to grow about 1 to 2 percent per year through 1982. Growth of
the market will be affected by population growth, laundry habits, and
competition from the liquid detergent market.
The major steps in manufacturing spray-dried detergent are: mixing
raw materials to form a detergent slurry, drying the slurry by contacting
it with hot air in a spray-drying tower, cooling product granules, adding
heat-sensitive materials, and packaging.
The main pollutant from the production of powdered detergent is
particulate in the form of detergent dust from the exhaust of the spray-
drying tower. An average of 13 emission tests show that typical
controlled emissions from the spray dryer are 5 kg/h (11 Ib/h). Nationwide
controlled emissions were calculated to be 164 kg/h (363 Ib/h) or
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988 Mg/yr (1,089 tons/yr). Emissions from raw material and final product
transport and handling are estimated to be minor.
Presently, two basic systems are used by the industry to control
emissions from the spray dryer. One system consists of one or more
cyclonic impingement scrubbers which use a high-solids concentration
detergent slurry. The other system uses dry cyclones followed by a water
scrubber and electrostatic precipitator. Both systems allow for product
recovery and are estimated by the industry and equipment vendors to be
approximately 99 percent efficient.
Typical State Implementation Plan (SIP) particulate regulations for
new plants are expressed by the process weight equation:
E = 4.1p°-67
where E = allowable particulate emissions, in Ib/h, and
p = process weight rate in tons/h.
The recommended method for sampling particulates from the detergent
industry is EPA Reference Method 5.
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2.0 INTRODUCTION
The authority to promulgate New Source Performance Standards (NSPS)
is derived from Section 111 of the Clean Air Act. Under the Act, the
Administrator of the U.S. Environmental Protection Agency is directed to
establish air pollution standards and is accorded the following powers:
1. Identify those categories of stationary emission sources that
contribute significantly to air pollution and could be reasonably
anticipated to endanger the public health and welfare;
2. Distinguish clc ;es, types, and sizes within categories of new
sources for the purpose of establishing standards; and
3. Establish standards of performance for stationary sources which
reflect the degree of emission reduction achievable through application
of the best system of continuous emission reduction, taking into consid-
eration the cost, energy, and environmental impacts associated with such
emission reduction.
Detergent manufacturing was recently specified on a priority list of
major source categories for which an NSPS should be developed.1 This
source category survey was performed to determine if an NSPS for the
detergent manufacturing industry is needed and to identify the processes
and pollutants which should be subject to regulation. Information about
processes, air pollutants, and control equipment was gathered as follows:
1. Process and emission data were collected from literature searches,
state and local air pollution control agencies, detergent manufacturing
companies, and the National Emission Data System (NEDS).
2. Four detergent manufacturing plants were visited to develop an
understanding of manufacturing processes and to collect data on air
pollution control equipment and emissions.
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3. Representatives of industry, government agencies, and trade
associations were contacted to gather information on detergent production
and projected industry expansion.
A detergent is any substance that lowers the surface tension of
water. Detergents clean by acting as a wetting agent and by holding
soils in suspension. Scientifically, the term detergent applies to both
soap and synthetic detergents. However, in common usage (and for the
purposes of this report), soap and detergents are distinguished both by
their composition and by their cleaning performance. Soap precipitates
as a calcium salt and therefore is not effective in hard water. Detergent,
a synthetic organic compound, is augmented by water softeners, buffering
agents, and builders and is effective in hard and soft water.2 3 4 5
The U.S. synthetic detergent industry grew rapidly in volume shortly
after World War II. Prior to that time, essentially all cleaning and
laundry compositions were based on fatty acid soaps derived from natural
fats and oils such as tallow and coconut oil.6 Modern soap and detergent
formulations were shaped by a series of events which started in the
1930's when the first synthetic surface-acting agent (surfactant), a long
chain alkyl-aryl sulfonate, was introduced.4 Factors that contributed to
increased consumption of synthetic detergent included the development of
economical processes for the manufacture of alkyl-benzene, the discovery
and utilization of phosphate detergent builders, introduction of automatic
washing machines, steady growth in consumer purchases of clothes, an
increase in washing frequency, and increases in the population.6
Numerous brands of laundry detergent are on the market. A large
number of these have multiple formulas to meet regional phosphorus
legislative requirements. There is no "typical" heavy-duty laundry
detergent formulation; products may be characterized as high or low
foamers, phosphate or zero-phosphate compositions, anionic or nonionic,
built or unbuilt, and any combination thereof. However, most detergent
formulations contain at least the following: surfactants, builders, foam
regulators, solubilizers, corrosion inhibitors, and fillers and diluents.
Table 2-1 gives common components of laundry detergent and their function.
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TABLE 2-1. COMPONENTS OF POWDERED LAUNDRY DETERGENT
IN THE UNITED STATES6
Components
Commercial examples
Percent
composition
by weight
Function
Surfactants
Builders
Foam
regulators
Solubilizers
Antirede-
position
agents
Linear alkylbenzene sulfonates
Alcohol sulfates
Alcohol ethoxylates 8-22
Alcohol ether sulfates
Sodium tripolyphosphate
Tetrapotassium pyrophosphate
Tetrasodium pyrophosphate 20-60
Sodium citrate
Zeolites
Soap
Alkanolamides 0-5
Fatty amine oxides
Lauryl alcohol
Ethanol 0-2
Sodium xylene sulfonate
Carboxymethylcellulose <1
Lower surface tension; promote
emulsification of oil and grease;
facilitate penetration of the fabric
structure; assist in dispersion of
particulate matter; produce foam
Sequester calcium and magnesium ions;
prevent redeposition of soil on
fabric; maintain alkalinity necessary
for cleaning; disperse and suspend
dirt; increase the efficiency of the
surfactant
Boost, stabilize, and control foam;
Increase the ability of surfactants to
go into solution when surfactant
content is at a high level;
Prevent removed dirt from returning
to the fabric
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TABLE 2-1. COMPONENTS OF POWDERED LAUNDRY DETERGENT
IN THE UNITED STATES6
(concluded)
Components
Commercial examples
Percent
composition
by weight
Function
cr>
Fluorescent
whiteners and
blueing agents
Corrosion
inhibitors
Perfumes and
colorants
Fillers and
diluents
Sodium silicate
Sodium sulfate
Sodium carbonate
Sodium silicate
Provide a blue-white whiteness to
<1 counteract the natural tendency
of some fibers to yellow
4-10 Protect metal parts of washing machine
<1 Improve aesthetic appeal
Provide matrix for free-flowing
20-40 powder formulations; provide medium
for compositions; assist processing
of the detergent formulation
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The Standard Industrial Classification (SIC) number 2841 includes
soaps, organic detergent (liquid and powder laundry detergent and
dishwashing liquid), alkaline detergent (automatic dishwashing detergent),
glycerin made from fats, and scouring powders. Surfactant, the active
ingredient in detergents, is classified in a separate SIC number 2843.7
Technical articles, emission data from state agencies, and discussions
with industry representatives indicate that the manufacturing of spray-
dried powdered detergent is a significant source of particulate emissions
whereas other processes in the industry are not.4 8 9 10 Therefore, this
study will focus on the production of spray dried powdered detergent.
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3.0 CONCLUSIONS AND RECOMMENDATIONS
3.1 CONCLUSIONS
1. Growth in the liquid and powdered detergent industry has been
slow for the past 10 to 15 years and is projected to be about 1 to
2 percent per year through 1982. No new spray dryers are expected to be
built within the next 10 years because existing production capacity can
meet the projected demands. No spray dryer modifications or
reconstructions are expected because spray dryers last indefinitely.
2. The primary pollutant from the manufacture of spray-dried detergent
is particulate from the spray-drying operation. Minor sources of emissions
are raw material and product handling.
3. Control technology is available for particulate (detergent dust)
pollution control. There are no uncontrolled plants in the United States
because the value of recovered detergent dust justifies a high level of
control.
4. Emission data are available for approximately two-thirds of the
plants which manufacture spray-dried detergent. Test data show that
particulate emissions from plants average 60 percent of emissions allowed
by a typical SIP process weight equation.
5. The standard method for evaluating particulate emissions from
spray-drying detergent is EPA Reference Method 5.
3.2 RECOMMENDATIONS
It is recommended that an NSPS not be developed at this time for the
detergent industry. A standard would have no impact because no facilities
are expected to be covered by the standard in the next 10 years.
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4.0 DESCRIPTION OF INDUSTRY
4.1 SOURCE CATEGORY
The source category considered in this report is the manufacture of
spray-dried detergent. This category represents approximately 45 percent
of the total products listed under SIC Code 2841.xl The spray-dried
detergent and soap source category is defined individually by NEDS Source
Classification Code 3-01-009-01.
Table 4-1 shows that the number of establishments and employees
associated with SIC Code 9841 has been rather stable for the past 20 years.
The total number of establishments has decreased in the past 10 years,
but this decline was probably offset by an increase in establishments
with 20 or more employees. The total number of employees has increased
from 30,800 in 1963 to 31,900 in 1977.12 13 14 15
Of the 227 establishments listed under SIC Code 2841 in 1977, 33
presently spray dry detergents (Table 4-2). Facilities are located
in 17 states across the country. Three major companies, Procter and
Gamble Company, the Colgate-Palmolive Company, and Lever Brothers Company,
supply more than 90 percent of the retail market demand for detergent and
produce detergent only by spray drying.16 Several other companies,
including Purex Corporation and Witco Chemical Corporation, manufacture
spray-dried detergent to package under their own label or to sell to
distributors. The remaining companies, although large in number, produce
less than 5 percent of the total laundry detergent used in the United
States. These small operations generally produce detergent by dry mixing
ingredients rather than by spray drying.
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TABLE 4-1. INDUSTRY STATISTICS12 13 14 1S
Year
1977
1972
1967
1963
1958
Total No.
of plants
638
642
668
704a
608a
No. of
plants
with >20
employees
227
199
207
172a
163a
Total No. of
employees
(1,000)
31.9
31.5
30.3
30. 8a
29. 6a
No. of
production
employees
(1,000)
20.4
20.4
20.2
20. la
18. 2a
Data for 1963 and earlier are not directly comparable to more recent
data because the industry classification was changed.
10
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TABLE 4-2. SPRAY-DRY DETERGENT MANUFACTURERS, 1980
Company
Location
The Procter and Gamble Company
The Colgate-Palmolive Company
Lever Brothers
Astor Products
Chemithon
Custom Spray Products, Inc.
The Great Atlantic and Pacific
Tea Company, Inc.
Los Angeles Soap Company
Luseaux Labs
National Purity Soap and
Chemical Company
Pacific Soap
PI ex Chemicals
Long Beach, California
Sacramento, California
Augusta, Georgia
Kansas City, Kansas
Alexandria, Louisiana
Baltimore, Maryland
Quincy, Massachusetts
New York, New York
Cincinnati, Ohio
Dallas, Texas
Berkeley, California
Jeffersonville, Indiana
Kansas City, Kansas
Jersey City, New Jersey
Los Angeles, California
Baltimore, Maryland
St. Louis, Missouri
Jacksonville, Florida
Seattle, Washington
Atlanta, Georgia
Brockport, New York
Los Angeles, California
Gardena, California
Minneapolis, Minnesota
San Diego, California
Union City, California
11
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TABLE 4-2. SPRAY-DRY DETERGENT MANUFACTURERS, 1980
(concluded)
Company
Location
Purex
Safeway Stores, Inc.
Stepan Chemical
Witco Chemical Corporation
Southgate, California
St. Louis, Missouri
Bristol, Pennsylvania
Oakland, California
Chicago, Illinois
Chicago, Illinois
Paterson, New Jersey
12
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4.2 PRODUCTION
Production of powdered detergent has increased slowly in the past 10
to 15 years. From 1963 to 1977, production increased 37 percent, from
2.4 to 3.3 billion pounds (Figure 4-1).6 12 13 14 1S Growth in the
detergent market (powders and liquids) is projected to continue at about
1 to 2 percent per year through 1982.6 18
The powdered detergent market will be affected by population growth,
changes in consumer laundry habits, and competition from the liquid
laundry detergent market.6 16 17 Rising energy costs will also affect
the spray drying manufacturing process. Although population growth is
expected to increase the total detergent demand by 500 million pounds by
1985, changes in consumer laundry attitudes and competition from the
liquid detergent market may offset the demand for powders.6 16 17 18 The
liquid detergent market has increased from 3.4 percent (1968) to
16.1 percent (1977) of the home laundry detergent market, and it is
expected to increase to ^8 to 21 percent by 1982.6 Much of the growth in
the total detergent industry is expected to be met by the expanding
liquid market.11
No new spray driers are expected to be built in the next 10 years to
meet the modest growth forecast for the detergent industry.19 20 21
Industry representatives from two major companies have stated that they
will probably never build another spray dryer. Excess capacity exists in
the industry to meet projected powdered detergent demand; some plants
spray-dry only two shifts per day, and others have idle spray dryers.19
20 21 The average capacity utilization of spray-dried detergent is
estimated to be near 60 percent.
4.3 PROCESS DESCRIPTION
Manufacture of spray-dried detergent has three main processing
steps: slurry preparation, spray drying, and granule handling (Figure 4-2).
4.3.1 Slurry Preparation
Detergent slurry is produced by blending liquid surfactant with
other powdered and liquid materials (builders and other additives) in a
crutcher (a closed mixing tank). The blended slurry is held in a surge
vessel for continuous pumping to the spray dryer. Solids content of the
13
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Million
Pounds
5,000 •
4,000 •
3,000 •
2,000 •
500 -
400 •
300 -
200 -
100 •
.
.
^-"' 'x.x- Household Powdered
/ ^^ Detergent
,
* ^
XNonhousehold Powdered
Detergent
Soap Powder and Flakes
r •
1 1 1 1 1
Million
kg
2,268
-1,814.4
-1,360.8
. 907,2
226.8
• 181
• 136
- 90.7
45.4
1960 1965 1970 1975 1980
Figure 4-1. Production of Powdered Detergent and Soap
14
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RECEIVING
STORAGE
TRANSFER
SLURRY PREPARATION
SPRAY DRYING
BLENDING
AND
PACKING
SURFACTANTS:
LAS SLURRY ALCOHOLS
ETHOXYLATES
BUILDERS:
PHOSPHATES SILICATES
CARBONATES
ADDITIVES:
PERFUMES DYES
ANTI-CAKING AGENTS
TO
CRUTCHER
AND POST-
ADDITION
MIXER
FINISHED
DETERGENTS
TO
WAREHOUSE
Fiqure 4-2. Manufacture of spray-dried detergents.
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slurry varies from 50 to 70 percent by weight at most plants. Dust
emissions are generated by handling and conveying of the powders, but
these emissions are contained in the building or controlled with fabric
filters and are not considered significant.8 10
4.3.2 Spray Drying
The spray-drying operation is the major source of particulate emissions
from detergent manufacturing.4 8 9 10 It is also a minor source of [
hydrocarbons when the product being sprayed contains organic materials
with low vapor pressures.
Slurry feed to the tower is atomized by spraying at high pressure
through nozzles. Typical towers are cylindrical with cone-shaped bottoms
and range in size from 3.7 to 7.4 m (12 to 24 ft) in diameter and 30 to
38 m (100 to 125 ft) in height. Typical feed rates vary from 5,400 to
6,800 kg/h (12,000 to 15,000 Ib/h). Air is supplied to the tower from
direct-heated furnaces fired by either natural gas or fuel oil. Most
towers designed for detergent production are countercurrent, with slurry
introduced at the top and heated air introduced at the bottom. A few
towers are concurrent and have both hot air and slurry introduced at the
top.
Tower operating parameters vary widely from manufacturer to
manufacturer and product to product. Heated air supplied to the tower
varies from 315°C to 400°C (600°F to 750°F). Moisture content of the
final product varies from 10 to 17 percent. Exit gas temperatures range
from 65°C to 120°C (150°F to 250°F).
In countercurrent towers, the low air velocities and large particle
size allow most of the dried granules to fall to the bottom of the tower.
The granules are discharged through a regulated opening (star valve)
while still hot. In concurrent towers, the air is vented just above the
bottom of the tower through a baffle, changing the direction of the air
and causing the dried granules to fall to the cone bottom. The loss of ;
detergent fines is higher from the concurrent towers than from the ;
countercurrent towers because the particles produced in concurrent towers
are smaller.10
16
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4.3.3 Granule Handling
Granules are mechanically or air conveyed from the tower to a mixer
to incorporate additional dry or liquid ingredients. Air conveying cools
the granules during transport. At the end of the conveyor, centrifugal
separators remove granules from the air. The cooled granules are screened
i to remove oversized or undersized particles, blended with final heat-
| sensitive additives, and conveyed to packaging and storage. The conveying,
mixing, and packaging of granules cause in-plant dust emissions which are
generally controlled by baghouses.8 10
17
A
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5.0 AIR EMISSIONS
5.1 PLANT AND PROCESS EMISSIONS
Emission test data for specific plants were requested from state and
local control agencies and individual plants. Additional emission data
were obtained from a previous EPA testing program, EPA's National Emissions
Data System (NEDS), and other literature sources.4 8 10 Table 5-1
presents a compilation of testing results and emission estimates obtained
in this survey. The 22 plants for which data were obtained have a
production and emission range which is characteristic of the 33 plants
which spray-dry detergent in the United States. Emissions range from 0.6
to 20 kg/h (1.3 to 44 Ib/h). Testing results show that the average
emission rate is 5 kg/h (11 Ib/h), which is 30 Mg/yr (33 tons/yr), assuming
a 3-shift day and 5-day workweek, 50 weeks per year.
Table 5-2 shows the average emission rate (calculated by averaging
emission test data) and SlP-controlled emission rate for a typical
detergent plant. The typical SlP-controlled estimate was obtained by
dividing the total 1977 U.S. production of powdered laundry detergent by
the number of plants in operation. This production rate (in tons of
detergent per year) was converted to an average plant detergent slurry
feed rate (process weight rate). The process weight rate was used in a
typical process weight equation:
E = 4.1p°-67
where E = allowable particulate emissions, in Ib/h, and
p = process weight rate, in tons detergent slurry/h.
This typical process weight equation is used in 10 of the 19 states which
have detergent plants in the U.S.
18
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TABLE 5-1. EMISSION DATA
Plant
A
B
C
D
E
F
G
H
Date
of data
1972
7/73
4/73
5/72
7/72
6/72
1973
4/73
1973
2/74
Method
EPA 5
EPA 5
EPA 5
EPA 5
EPA 5
EPA 5
EPA 5
EPA 5
EPA 5
EPA 5
N
Control
device
cyclonic
Impingement
scrubber
cyclonic
Impingement
scrubber
baghouse
cyclone
Impingement
scrubber
cyclone,
scrubber-ESP
cyclone,
scrubber-ESP
cyclonic
Impingement
scrubber,
fiberglass
filter
cyclonic
impingement
scrubber
Emission
range
Ib/h
0.7-2.4
7.5-8.65
6.35-16.81
44.11-45.19
3.15-4.65
17.3-23.11
— —
6.4-9.03
8.6-13.6
1.6-5.3
Emission
average
Ib/h
1.66
8.02
9.35
44.11
3.78
21.01
25
8.1
10.6
3.2
Emission
average
kg/h
0.8
3.6
4.2
20.0
1.7
9.5
11.3
3.7
4.8
1.4
No. of
tests
3
3
3
2
3
3
—
3
3
3
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TABLE 5-1. EMISSION DATA
(Continued)
ro
o
Date
Plant of data
I 1975
J 1977
K 1978
L 1978
M
N
0
P
Q
R
Method
EPA 5 Mod.
EPA 5 Mod.
EPA 5 Mod.
EPA 5 Mod.
EPA 5 Mod.
Estimate*
Estimate
Estimate
Estimate
Estimate
Control
device
cyclonic
impingement
scrubber
cyclone,
scrubber-ESP
NA
cyclone
cyclonic
scrubber
cyclone,
scrubber-ESP
cyclone,
scrubber-ESP
cyclone,
scrubber, -ESP
cyclonic
impingement
scrubber
cyclone,
wet scrubber
Emission Emission
range average
Ib/h Ib/h
5.2-9.5 6.9
14
4
1.4
4.8
6.6b
15b
10.7b
3.7b
25 tons/yr- 17.8b
82 tons/yr
Emission
average
kg/h
3.1
6.4
1.8
0.6
2.2
3.0b
6.8b
4.8b
1.7b
8.1b
No. of
tests
4
M
-
-
_
0
0
0
0
0
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TABLE 5-1. EMISSION DATA
(Continued)
Date
Plant of data
S
T
U
V
Method
Estimate
Estimate
Estimate
Estimate
Emission
Control range
device Ib/h
cyclone
cyclone,
scrubber-ESP
cyclone
cyclone
Emission
average
Ib/h
1.3b
6b
9.6
1.6
Emission
average
kg/h
0.6b
2.7b
4.4
0.7
No. of
tests
0
0
0
0
Esimates were made by state agencies based on efficiency of the air
pollution control devices installed at. the plant. It is not known if
these estimates are accurate.
Estimate assumes plants operate 6,000 h/yr.
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TABLE 5-2. PARTICULATE EMISSIONS
FROM A TYPICAL SPRAY DRYER
Typical spray dryer emissions:
Uncontrolled 500 kg/h (1,100 Ib/h)
Controlled for product 50 kg/h (110 Ib/h)
recovery only
Average controlled:3 5 kg/h (11 Ib/h)
Typical SIP controlled:5 9 kg/h (19 Ib/h)
Average plant emissions were estimated by averaging
.available test results.
Typical plant emissions were estimated assuming a
production rate of 45,300 Mg/yr (50,000 tons/yr),
a process weight rate of 57,000 Mg/yr
(62,500 tons/yr), and an operating rate of
6,000 hours per year.
22
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Data obtained from state agencies and detergent companies indicate
that the detergent plants commonly emit less participate than is allowed
by SIP's. A comparison of the average emission rate and the SIP-
controlled emission rate shows that plants are emitting 60 percent of the
particulate allowed by the typical state regulations.
No uncontrolled detergent plants exist in the United States because
it is not profitable for the plants to lose detergent powder to the
atmosphere. Plants which use collection devices only for product recovery
remove 85-95 percent of particulate emissions. These plants are estimated
to emit 50 kg/h (110 Ib/h).
5.2 TOTAL NATIONAL EMISSIONS
Baseline nationwide particulate emissions are estimated to be
988 Mg/yr (1,089 tons/yr). The nationwide emission rate was estimated by
multiplying the average plant emission rate by the number of plants which
spray-dry detergent in 1980.
23
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6.0 EMISSION CONTROL SYSTEMS
6.1 CONTROL APPROACHES
There are three sources of particulate emissions in the manufacturing
of spray-dried detergent: unloading, conveying, and mixing dry materials;
spray-drying detergent slurry; and conveying and packaging the final
product. The major source of emissions, the spray drying of detergent
slurry, generally is controlled in two stages. A primary control device
(dry cyclone or cyclonic impingement scrubber) is used largely for product
recovery, and a secondary device [mist eliminator or scrubber-electrostatic
precipitator (ESP) unit] is used for particulate air pollution control.
The other emission sources are controlled by fabric filters which serve
both for air pollution control and product recovery.
6.1.1 Emission Control for the Spray Dryer
6.1.1.1 Primary Collection Equipment. Two types of primary collection
equipment are used by the soap and detergent industry to control emissions
from spray drying—the dry cyclone and the cyclonic impingement scrubber.
The dry cyclone is used in parallel or in series to collect particulate
(detergent dust) and recycle the dry product back to the crutcher. The
cyclonic impingement scrubber is used in parallel and collects the
particulate in a scrubbing slurry which is recycled back to the crutcher.
The cyclone separates particulate matter from the effluent gas by
changing the direction and velocity of the inlet stream. Centrifugal
force moves the particulates to the outside wall for collection. The
cyclone's collection efficiency is dependent on the inlet gas velocity
and the particle size in the gas stream.
Because the particulates in the gas stream from the spray dryer are
large (approximately 50 percent are greater than 40 microns), the cyclone
efficiency is high.8 22 Typically, a single cyclone is 90 percent efficient
24
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with a pressure drop of 1,000 to 1,250 Pa (4 to 5 inches of water).10 26
Two cyclone collectors in series operate at 3,000 Pa (12 inches of water)
and are reported to have collection efficiencies of 99 percent.10
In cyclonic impingement scrubbers, the air stream enters tangentially
near the bottom and flows upward in a spiral. A countercurrent flow of
high-solids-concentration slurry is used to contact the dust particles
and absorb them. The scrubbing slurry drains out of the bottom of the
unit, and the clean air leaves through the top.4 The slurry is recycled
through the scrubber at a constant solids concentration by continuously
returning part of the slurry to the process and diluting the remaining
slurry with water.
The efficiency of the cyclonic impingement scrubber depends on a
proper balance between the air and the scrubbing slurry flow rates.23
Pressure drop varies from approximately 500 to 2,000 Pa (2 to 8 inches of
water), and the slurry flow rates vary from 0.5 to 1.3 liters of slurry
per cubic meter of air (4 to 10 gpm slurry per 1,000 cfm air).10 The
equipment manufacturer states that this type of scrubber has an efficiency
of at least 99 percent for particles greater than 3 microns.24 2S
6.1.1.2 Secondary Collection Equipment. Secondary collection
equipment is used at well-controlled detergent plants to capture the
fine particulates that have escaped from the primary devices. Plants
with cyclonic impingement scrubbers often use mist eliminators as secondary
collectors. Dry cyclones may be followed by fabric filters or, more
commonly, by scrubber-electrostatic precipitator units. Generally, it is
not economical to recover the portion of the product captured by secondary
devices; collected material is disposed as solid or liquid waste.
A typical scrubber-ESP unit is enclosed in a cyclindrical vessel
about 4.3 m (14 ft) in diameter and about 12.2 m (40 ft) high. A tubular
type ESP is located in the upper part of the vessel. The scrubbing
section, in the lower part of the vessel, contains a 23-cm (9-inch) layer
of pall ring packing with spray nozzles underneath. Each scrubber uses
fresh water at about 4.1xlO-3 to 5.7xlO-3 m3/s (65 to 90 gpm). The
collected material is washed from the ESP tubes with water every 3 to
5 days while the unit is shut down.26 The scrubber-ESP unit collects
25
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small particle sizes, has low pressure and temperature drops, operates
continuously, has a low maintenance costs, and requires little power to
operate.10 It is approximately 50 percent efficient.26
Although fabric filters have been used by some companies to control
the spray dryer, few are presently used for this purpose. Problems with
bag blinding and bag burning made fabric filters undesirable control
devices for the spray dryer.
6.1.2 Emission Control for Raw Material and Final Product Handling
Fabric filters are used extensively for the control of dust emissions
from raw material unloading, conveying, and mixing, and from product
conveying and packaging. Filter material such as polyester and Dacron is
used to control emissions from raw material handling because it is
resistant to alkaline powders. Fabric filters used for final product
emission control may be made of cotton sateen.
The fabric filters used in the industry vary in inlet capacity from
9.4 m3/s (20,000 acfm) for small units to 37.8 mVs (80,000 acfm) for
large units.10 Air-to-cloth ratios range from 2.5 to 1 to 6 to 1.10 27
Some manufacturers report efficiencies of fabric filters exceed
99.8 percent.27
6.2 "BEST SYSTEMS" OF EMISSION REDUCTION
Two major control systems are used by the soap and detergent industry.
The control system most widely used consists of a cyclonic impingement
scrubber occasionally followed by a mist eliminator or similar type of
secondary aftercollector. A second system consists of cyclones in parallel,
followed by a scrubber-ESP unit. Both systems can achieve effective
product recovery and air pollution control. Design collection efficiencies
for both systems are approximately 99 percent according to the detergent
companies and control equipment vendors.
26
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7.0 EMISSION DATA
7.1 AVAILABILITY OF DATA
Emission data were obtained through telephone and letter contacts to
state and local control agencies, visits and letters to individual
companies, and the NEDS. In addition, particulate emission rates and
particle size distribution were obtained from a previous EPA testing
program of six detergent plants. Most of the emission data that was
available was only for the spray-drying operation. Little data was found
on other steps in the manufacturing of powdered detergent and on the
manufacture of other detergent products (such as liquid detergent and bar
soap). A small amount of data on N02, S04, P04, C04, and Si02 emissions
from a spray dryer were provided by an EPA test at one plant.
Data on uncontrolled plants is not available in the United States
because all detergent spray dryers are controlled to prevent loss of
product.
7.2 SAMPLE COLLECTION AND ANALYSIS
Particulate emissions from detergent manufacturing are measured
using EPA Reference Method 5. EPA Reference Method 9 is available for
determination of opacity. Both EPA Reference Methods 5 and 9 are described
in 40 CFR 60, Appendix A.28
27
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8.0 STATE AND LOCAL EMISSION REGULATIONS
The following paragraphs provide information on pertinent state and
local regulations. These data were compiled from telephone contacts and
letter requests to specific pollution control agencies and from the
Environment Reporter.29
Spray dry detergent manufacturing plants operate in 17 states. All
17 states have emission regulations for particulate, and all except two
regulate opacity (Table 8-1). None of the states has developed emission
standards specific to new or existing detergent manufacturing plants;
most state regulations categorize this source as a "manufacturing"
process.
Seven of the seventeen states listed in Table 8-1 use the following
process weight rate equations to establish allowable particulate emissions:
E = 4.10 p°-67 p^30 tons/h
E = 55.0 p0-11-^ p>30 tons/h
where E = allowable particulate emission rate, in Ib/h, and
p = process weight rate, in tons slurry/h.
The remaining ten states have different process weight rate tables
and equations. The California South Coast Air Quality Management District
(SCAQMD) uses a more restrictive table than the other states. An average-
sized plant (with a process weight rate of 10 tons/h) which would be
allowed to emit 8.6 kg/h (19 Ib/h) of particulate using the above equations
would be limited to emitting 5.4 kg/h (12 Ib/h) particulate in the SCAQMD.
Most states which have detergent manufacturing plants limit opacity
to 20 percent with exceptions which permit higher levels for a small
percentage of time in an hour or day.
All state and local agencies contacted indicated that their detergent
plants were operating within applicable particulate regulations. To meet
28
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TABLE 8-1. SUMMARY OF STATE AIR POLLUTION REGULATIONS
State
Particulate
Opacity
Air pollution regulation reference
ro
10
California
Bay Area Equation Set T
South Coast Process weight
rate table 405,
Type A
§20, exception
520, exception
Bay Area Air Control District, Reg. IV.
September 1977.
Rules and Regulations South Coast Air Quality
Management District, Reg. IV. September 1977.
Florida
Georgia
Illinois
Indiana
Kansas
Louisiana
Maryland
Equation set 2
Equation set 1°
Equation set 3
Equation set 1
Equation set 1
Equation set 1
SO. 03 gr/dscf
S20, exception
^20, exception
530, exception
540, exception
—
_ — _
520, exception
Rules of the Florida Department of Environment
Regulation. Chapter 17-2.13. September 1979.
Georgia Air Quality Control Rules. Chapter 391-3-1.
November 1975.
Illinois Stationary Sources Standard.
Rule 201, 202, 1977. May 1979.
Indiana Air Pollution Control Regulations. APC-3.
May 1979.
Kansas Air Pollution Control Regulations.
Section 28. January 1974.
Louisiana Air Pollution Control Regulations.
19.4 and 19.5. February 1978.
Maryland State Department of Health and Mental
Hygiene Regulations Governing the Control of Air
Pollution. Area HI. April 1979.
-------
TABLE 8-1. SUMMARY OF STATE AIR POLLUTION REGULATIONS
(continued)
State
Massachusetts
Minnesota
Missouri
New Jersey
New York
Ohio
Pennsylvania
Parti cul ate
Table 6
Equation set 2
Equation set 1
5.02 g/dscf or
99% reduction
Equation set 4e
Equation set 1
5.02 g/dscf or f
or Equation 5
Opacity
520,
520,
520,
520,
520,
520,
520,
exception
exception
exception
exception
exception
exception
exception
Air pollution regulation reference
Massachusetts Air Pollution Control Regulations.
Section 7.09(u). October 1978.
Minnesota Air Pollution Control Rules, Regulations,
and Air Quality Standards. APC-5. June 1976.
Missouri Air Pollution Control Regulation.
10 CSR 10-5. December 1979.
New Jersey Regulations on Air Pollution from
Manufacturing Processes. Subchapter 6. May 1977.
New York Regulations on Processes and Exhaust.
Title 6, Chapter III, Part 212. June 1973.
Ohio Particulate Matter Standards. September 1978.
Pennsylvania Standards For Contaminants.
Section 123. July 1978.
Texas
Equation set
520, exception Texas Regulation 1: Control of Air Pollution From
Visible Emissions and Particulate Matter.
Section 131. May 1979.
Washington 50.1 gr/dscf
520, exception Washington General Air Pollution Regulations.
WAS 173-400-040. December 1976.
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TABLE 8-1. SUMMARY OF STATE AIR POLLUTION REGULATIONS
(continued)
Equations
E = allowable emission rate in Ibs/h
p = process weight rate in tons/h
aEquation set 1:
(a) E = 4.1p°-67 p^30 tons/h
(b) E = SSp0-11-^ p>30 tons/h
Equation set 2:
(a) E = 3.59p°-62 pg30 tons/h
(b) E = 17.31p°-16 p>30 tons/h
cEquation 1 (a) above is used for all existing equipment.
Equation set 3:
(a) E = 2.54p°-534 pS450 tons/h
(b) E = 24.8p°-16 p>450 tons/h
New sources are subject to the restrictions of this equation. Existing sources are subject to the
restrictions of Equation Set 1.
eEquation set 4:
(a) E = 0.024p°-665 pS50 tons/h
(b) E = 39p°-b82-50 p>50 tons/h
Equation set 5:
(a) A = 0.76E0-42 where
A = allowable emissions in Ib/h
E = FxW
F = process factor in Ib/unit = 30 Ib/ton for detergent drying, and
W = production or charging rate in units/h.
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TABLE 8-1. SUMMARY OF STATE AIR POLLUTION REGULATIONS
(concluded)
Equation set 6:
E = 0.048q°-62
q = stack effluent flow rate in acfm.
If the source has an effective stack height less than the standard effective stack height,
the allowable emission level must be reduced.
OJ
ro
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increasingly stringent air pollution control laws in some states, the
industry has added control equipment for particulate and opacity reduction
and has increased maintenance checks on existing control equipment.
Personnel from a few states mentioned occasional complaints about detergent
"fallout," but stated that this problem was generally caused by equipment
failure or process upset conditions at the plant. There are occasional
complaints in some areas concerning odors from detergent plants, but
these problems have usually been corrected by changes in the process or
by further addition of control equipment.
33
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9.0 REFERENCES
1. U.S. Environmental Protection Agency. Code of Federal Regulations.
Title 40, Chapter I, Subchapter C, Part 60.16. Washington, D.C.
Office of the Federal Register. August 21, 1979.
2. Standard and Poor. Industrial Surveys: Chemical Basic Analysis.
August 30, 1979. p. C25-C26.
3. Train, R. E., J. L. Agee, A. Cywin, and R. T. Gregg. Development
Document for Effluent Limitations Guidelines and New Source
Perfonnance Standards: Soap and Detergent Manufacturing Point
Source Category. U.S. Environmental Protection Agency. Washington,
D.C. Publication No. EPA-440/1-74-018a. April 1974. 202 p.
4. Boys, P. A. Air Pollution Control Technology and Costs in Seven
Selected Areas. U.S. Environmental Protection Agency, Research
Triangle Park, N.C. Publication No. EPA-450/3-73-010. December
1973. 708 p.
5. Shreve, R. N. and J. A. Brink, Jr. Chemical Process Industries.
New York, McGraw-Hill Book Company, 1977. p. 482-506.
6. Stanford Research Institute. Chemical Economics Handbook.
Menlo Park, CA. September 1978.
7. Standard Industrial Classification Manual. Bureau of the Census.
Washington, D.C. 1972. p. 583.8001 A-583.8001 M.
8. Phelps, A. H., Jr. Air Pollution Aspects of Soap and Detergent
Manufacture. Journal of the Air Pollution Control Association.
17:505-507. August 1967.
9. Environmental Engineering, Inc, PEDCo Environmental Specialists,
Inc. Draft Background Information for Establishments of National
Standards of Performance for New Sources. Contract No. CPA 70-142.
Task Order No. 8 for the Environmental Protection Agency.
Gainsville, Florida. July 1971. 46 p.
10. U.S. Environmental Protection Agency. Air Pollution Engineering
Manual. AP-40. Research Triangle Park, N.C. May 1973. p. 737-765.
11. Brenner, T. E. Soap and Detergents - North American Trends. Soap/
Cosmetics/Chemical Specialities, p. 44-52, 80-83. February 1978.
12. U.S. Department of Commerce: Bureau of the Census. Census of
Manufacturers. Washington, D.C. 1963. p. 28D-1 to 28D-18.
13. U.S. Department of Commerce: Bureau of the Census. Census of
Manufacturers. Washington, D.C. 1967, p. 28D-1 to 280-14.
34
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14. U.S. Department of Commerce: Bureau of the Census. Census of
Manufacturers. Washington, D.C. 1972, p. 28D-1 to 280-24.
15. U.S. Department of Commerce: Bureau of the Census. Census of
Manufacturers. Washington, D.C. 1977, p. 1-9.
16. Detergent Sales Expected to Reach $6.1 Billion by 1982. Soap/
Cosmetics/Chemical Specialities, p. 40. April 1978.
17. Slow Growth Predicted for Household Cleaning Products. Soap/
Cosmetics/Chemical Specialties, p. 48. November 1979.
18. Laundry Detergents to Lead Growth in Household Cleanser Market.
Soap/Cosmetics/Chemical Specialities, p. 47-49. August 1979.
19. Memo and attachments from Greer, L. E., Midwest Research Institute
to Eddinger, 0., EPA/ISB. April 1, 1980. Report of visit to the
Colgate-Palmolive Company (Jersey City, New Jersey plant) on
March 20, 1980.
20. Memo and attachments from Greer, L. E., Midwest Research Institute
to Eddinger, J., EPA/ISB. April 1, 1980. Report of visit to Witco
Chemical Corporation (Paterson, New Jersey plant) on March 21, 1980.
21. Memo and attachments from Greer, L. E., Midwest Research Institute
to Eddinger, J., EPA/ISB. April 25, 1980. Report of visit to Procter
and Gamble Company (Augusta, Georgia plant) on April 22, 1980.
22. Envirotech, Buell Emission Control Division. Buell Mechanical
Collectors. Form S202/0579. Lebanon, Pennsylvania. 1974. 8 p.
23. The Ducon Company, Inc. MuHivane Gas Scrubber. Bulletin
Number W-1273. Mineola, New York. 1973. 4 p.
24. Telecon. Sinclair, J., The Ducon Company, with Antel, D., Midwest
Research Institute. April 17, 1980. The performance of Ducon
scrubbers in the detergent industry.
25. The Ducon Company, Inc. Product Recovery and Air Pollution Control
and Penumatic Conveying. Bulletin No. A-9171a. Mineola, New York.
Undated. 4 p.
26. Bell, D. Procter and Gamble Testing Report, Augusta, Georgia. U.S.
Environmental Protection Agency. Contract Number 68-02-0233.
Research Triangle Park, N.C. June 1972. 93 p.
27. Telecon. Kury, W., W. W. Sly Mfg. Co., with Antel, D., Midwest
Research Institute. March 18, 1980. The use of fabric filters by
the detergent industry.
35
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28. U.S. Environmental Protection Agency. Code of Federal Regulations.
Title 40, Chapter I, Part 60, Appendix A. Washington, D.C. Office
of the Federal Register. July 1, 1979.
29. Stewart, J. D. Environment Reporter. Bureau of National Affairs,
Inc. Washington, D.C. 1979.
36
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before compietingl
T REPORT NO.
EPA/3-80-030
47TITLE AND SUBTITLE
2.
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
June 1980
Source Category Survey:
7. AUTHOR(S)
Detergent Industry
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
4505 Creedmoor Road
Raleigh, North Carolina 27612
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-3059
12. SPONSORING AGENCY NAME AND ADDRESS
ESED, OAQPS
U.S. Environmental Protection Agency
MD-13
Research Triangle Park. North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Background information is presented on the detergent manufacturing industry
for the purpose of assessing the need for new source performance standards. The
report contains information on industry statistics and processes, air emissions,
and emission control equipment associated with spray-dried powdered detergent.
The spray dryer used to produce powdered detergent is the only major source of
particulate emissions. No new spray dryers are expected to be constructed,
reconstructed, or modified within the next 5-10 years. The report recommends
that standards of performance should not be developed at this time.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS C. COSATI I icId/Group
Detergents
Surfactants
Spray dryers
Air pollution
Pollution control
Standards of performance
Air Pollution Control
13-B
18. DISTRIBUTION STATEMENT
Unlimited
19 SFC'.'F'T' CLASS TVir.s Rep:•»••..
Unclassif|ed
2C S* ~:;r>:~ •' Cl.AJS 'T-'is punt i
Unclassified
21. NO. OF PAGES
! 36
f~22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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Environmental Protection Office of Air Quality Planning and Standards
Agency Research Triangle Park NC 27711
Official Business Publication No EPA 450 3 80 030 Po«»o« and
Penalty for Private Use £e"p1id
Environmental
Protection
Agency
EPA 335
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