&EFA
tales
Analysis of the
Sources of Phosphorus
in the Environment
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EPA-560/2-79-002
CHEMICAL TECHNOLOGY AND ECONOMICS IN
ENVIRONMENTAL PERSPECTIVE
Task I - Analysis of the Sources of
Phosphorus in the Environment
FINAL REPORT
March 1979
Prepared under
Contract No. 68-01-3896
For
U.S. Environmental Protection Agency
Office of Toxic Substances
401 M Street, S.W.
Washington, D.C. 20460
Mr. Roman Kuchkuda
Project Officer
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DISCLAIMER
This report has been reviewed by the Office of Toxic Substances, U.S. En-
vironmental Protection Agency, and approved for publication. Approval does not
signify that the contents necessarily reflect the views and policies of the
U.S. Environmental Protection Agency, nor does mention of trade names or com-
mercial products constitute endorsement or recommendation for use.
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PREFACE
This report presents the results of an assessment and quantification of
the principal sources, both natural and anthropogenic, of phosphorus release
to the environment in the United States. Also included is an analysis of cer-
tain regional eutrophication case histories in which phosphate bans were ap-
plied to detergent products.
This study was performed by Midwest Research Institute under Contract No.
68-01-3896 for the Office of Toxic Substances of the U.S. Environmental Pro-
tection Agency. The Office of Toxic Substances' project officer for this study
was Mr. Roman Kuchkuda. Ms. Justine Welch of the Office of Toxic Substances
served as technical advisor on this task. Principal Midwest Research Institute
contributors to this study included: Mr. Charles E. Mumma (Task Leader),
Senior Chemical Engineer; Ms. Kathryn Bohannon, Assistant Chemist; and Mr. Fred
Hopkins, Junior Environmental Scientist. Dr. Thomas W. Lapp is the project
leader for this contract, under the supervision of Dr. Edward W. Lawless, Head,
Technology Assessment Section. .
Midwest Research Institute expresses its appreciation to the industrial
and governmental personnel who provided technical input and advice during
this study.
Approved for:
MIDWEST RESEARCH INSTITUTE
~: ~~irector
Environmental and Materials
Science~ Division
February 1979
11i
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CONTENTS
. .
. .
. .
Page
. . . . . . . . . . . . iii
. . . . . . . vi
. . . . . . . . . . . . . . . . viii
Preface.
Figures.
Tables.
. .
.
.
.
.
.
1. Introduction and Objectives . . . . . . . . . 1
2. Summary and Conclusions . . . . . . . . 4
Identification of phosphorus sources . . . 4
Quantification of principal phosphorus sources . . 7
Analysis of detergent phosphate legislation in Indiana and
New York . . . . . . . . . . . . . . . . 10
Conclusions . . . . . . . . . . . . . . . 11
3. Discussion of Methodology . . . . . . . . . . . . . . . . . . 12
Data acquisition and analysis . . . . . . . . . . . 12
Quantification of phosphorus sources . . . 14
References to Section 3 . . . . . . . . . . 17
4. Defini tion and Discussion of Terms . . . . . 20
Introduction . . . . . . . . 20
Eutrophication . . . . . . 20
Phosphorus analyses . . . . . . . . . . . . . . . 23
Chemical reactions and transport of phosphorus . . . 27
Sources of phosphorus . . . . . . . . . . . . . 33
Soils and phosphorus movement . . . . 35
Phosphorus removal . . . . . . 39
References to Section 4 . . . . . . . . . . 48
5. Identification of Phosphorus Sources . . . . . . . . 52
Natural sources . . . . . . . . . . . . . . . . . 52
Anthropogenic sources . . . . . . . . 55
Regional differences in phosphorus discharges . . . 65
Trends affecting phosphorus discharges . . . . . . . . 65
Current activities . . . . . . . . . . . . 68
References to Section 5 . . . . . 69
6. Quantification of Principal Phosphorus Sources . . . . . 73
Results of the national assessment . . . . . . . . 73
Regional quantification of phosphorus sources . . . . . . . 163.
Detergent phosphate bans in Indiana and New York . . . 171
References to Section 6 . . . . . . . . . . . . . . . 184
v
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Appendices
CONTENTS (continued)
A.
B.
.Conversion factors used in phosphorus terminology. . . . . . .
Descriptions of typical methodology used to calculate the esti-
mated total phosphorus emissions from industrial point
sources. . . . . . . . . . . . . . . . . . . . . . . . . . .
vi
Page
189
191
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Number
6-1
6-2
6-4
6-5
6-6
6-7
FIGURES
Page
4-1
Analytical scheme for differentiation of phosphorus forms
. . . .
26
4-2
Simplified flow diagram of municipal sewage treatment
......
42
5-1
Phosphorus transport in the environment
.............
53
5-2
Sources of phosphorus in receiving water
. . . .
54
.........
5-3
u.S. phosphorus production and domestic consumption (1975)
. . . .
56
Flow diagram for phosphate mining and processing--Eastern states.
83
Flow diagram for phosphate mining and processing--Western states.
87
6-3
Flow diagram for production of wet-process phosphoric acid
. . . .
89
Flow diagram for production of superphosphoric acid
. . . . . . .
94
Flow diagram for production of normal superphosphate
. . . . . . .
96
Flow diagram for production of granulated triple superphosphate
101
Flow diagram for production of run-of-pi1e triple superphosphate.
105
6-8 Flow diagram for production of ammonium phosphate . . . . . 108
6-9 Flow diagram for production of def1uorinated phosphate rock . . . 112
6-10 Flow diagram for production of animal-feed calcium phosphate 115
6-11 Flow diagram for production of elemental phosphorus . . . . . . . 117
6-12 Flow diagram for production of phosphoric acid (dry process) 121
6-13 Flow diagram for production of phosphorus pentoxide . . . . . . . 124
vii
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,-----
FIGURES (continued)
Number
Page
6-14 Flow diagram for production of phosphorus trichloride . . . . . . 126
6-15 Flow diagram for production of phosphorus oxychloride . . . . . . 129
6-16 Flow diagram for production of phosphorus pentasu1fide . . . . . . 132
6-17 Flow diagram for production of sodium t ri po1yphos phate . . . . . . 135
6-18 Flow diagram for production of sodium phosphates . . . . . . . . . 137
6-19 General flow diagram for production of food-grade calcium
pho s phat e s . . . . . . . . . . . . . . . . . . . .
. . . .
140
6-20 Flow diagram for production of laundry detergent
.........
145
B-1
Flow diagram for phosphate mining and processing--eastern states.
193
B-2
Flow diagram for production of normal superphosphate.
......
199
B-3
Flow diagram for production of phosphorus trichloride
......
206
viii
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Number
4-1
4-2
4-3
4-4
5-1
5-2
5-3
5-4
5-5
5-6
5-7
6-1
6-2
6-3
TABLES
Forms of Phosphorus Reported in Analytical Measurements. . .
Forms of Phosphorus Present in Surface and Wastewaters
. .. .
Products Utilizing Phosphate Rock-Derived phosphorus
Arranged by SIC Code. . . . . . . . . . . . . . .
. . . .
Basic Statistics from the Canada-Ontario Full-Scale Treat-
ability Study program--to Achieve an Effluent Phosphorus
Requirement of 1 mg/1iter. . . . . . . . . . . . . . . . .
Principal Industr~ Sources of Phosphorus-Containing Emis-
sions to Air - 1970. . . . . . . . . . . . . . . . . . . .
Total phosphorus Watershed Loading by Land Use and Land
Form in U. S . . . . . . . . . . . . . . . . . . . . . . . .
Phosphorus Concentration in Industrial Wastewaters. .
. . .
phosphorus Input to Municipal Waste Treatment Systems. . . .
Estimated Regional Consumption of P205 in Commercial phos-
phate Fertilizers Applied in 1976. . . . . . . . . . . . .
Regional Variations in Phosphate Loading
. . . . . . . . . .
Annual Trends in phosphorus Products. .
. . .
. . .
. . . .
Estimated National Nonpoint Source Discharges of Total phos-
phorus to the Environment in Precipitation Runoff and Air
Emissions in 1978 ......... . . . . . . . . . . .
Point Sources of Phosphorus Emissions to Air and Water
. . .
Sources and Estimates of Phosphorus-Containing Air Emissions
for Eastern and Western phosphate Rock Mining and Bene-
ficiation ........................
ix
Page
24
28
36
46
58
60
62
63
66
67
67
76
81
85
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NlUllber
6-4
6-5
6-6
6-7
6-8
6-9
6-10
6-11
6-12
6-13
6-14
6-15
6-16
Page
Emissions
. . . . . 92
Emissions
. . . . . 99
Emissions
. . . . . 104
TABLES (continued)
Sources and Estimates of Phosphorus-Containing Air
for Wet Process Phosphoric Acid Production. . .
Sources and Estimates of Phosphorus-Containing Air
for Normal Superphosphate Production. . . . . .
Sources and Estimates of Phosphorus-Containing Air
for Triple Superphosphate Production. . . . . .
Water Effluent Disposal and Containment Practices for the
Phosphate Fertilizer Industry. . . . . . . . . . . . . .
Sources and Estimates of Phosphorus-Containing Air Emissions
for DiammonilUll Phosphate Production. . . . . . . . . . .
Sources and Estimates of Phosphorus-Containing Air Emissions
for Production of Elemental Phosphorus. . . . . . . . . .
Sources and Estimates of Phosphorus-Containing Air Emis-
sions for Sodium Phosphates (excluding sodilUll tripoly-
phosphate) . . . . . . . . . . . . . . . . . . . . . . . .
Summary of Phosphorus-Bearing Raw Wastes from Food-
Grade Calcium Phosphate plants. . . . . . . . . . . . . .
Sources and Estimates of Phosphorus-Containing Air Emis-
sions for Food-Grade Calcium Phosphates. . . . . . . . . .
Typical Concentrations of Total Phosphorus in Raw Sewage at
Various Locations. . . . . . . . . . . . . . . . . . . . .
Sources of Phosphorus Loading in Treated Effluent from
Municipal Sewage Treatment plants. . . . . . . . . .
. . .
Effectiveness of Primary and Secondary Treatment
Processes on phosphorus Removal With and Without
Chemical Addition. . . . . . . . . . . . . . . . . . . . .
Phosphorus Load Estimates for Municipal Sewage Treatment
plan t s . . . . . . . . . . . . . . . . . . . . . . . . . .
110
111
120
138
141
142
149
150
151
155
-------
Number
6-17
6-18
6-19
6-20
6-21
6-22
6-23
6-24
6-25
6-26
B-1
B-2
B-3
TABLES (continued)
Estimated National Point Source Discharges of Total phos-
phorus to the Environment in 1978. . . . . . . . . . . . .
Summary of Estimated National Phosphorus Discharges to
the Environment in 1978. . . . . . . . . . . . . . . . . .
Estimated Quantities and Distribution of Total phosphorus
Discharged as Air Emissions in the United States
in 1978. . . . . . . . . . . . . . . . . . . . . . . . . .
Estimated Nonpoint Source Discharges of Total Phosphorus
to the Environment in Florida in 1978. . . . . . . . . . .
Estimated Point Source Discharges of Total Phosphorus
to the Environment in Florida in 1978. . . . . . . .
. . .
Summary 0.£ Estimated Phosphorus Discharges to Environment
in Florida in 1978 . . . . . . . . . . . . . . . . . . . .
phosphorus Loading in the Indiana Harbor Canal
. . .
. . . .
Average Phosphorus Concentrations and Treated Sewage Dis-
charge Rates in the purdue/FMC Study Area. . . . . . . . .
Major New York Sewage Treatment plant Discharges into
Lake Ontario During 1975 and 1976. . . .. . . . . .
. . .
1972 NES Lake and Reservoir Data for New York State. . . . .
Sources and Estimates of Phosphorus-Containing Air Emis-
sions for Eastern Phosphate Rock Mining and Beneficiation.
Sources and Estimates of Phosphorus-Containing Air Emis-
sions for Normal Superphosphate Production. . . . . . . .
Estimated 1978 phosphorus Load from Publicly Owned
Municipal Treatment plants. . . . . . . . . . .
.....
xi
Page
157
159
162
164
167
168
174
177
181
183
195
202
210
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SECTION 1
INTRODUCTION AND OBJECTIVES
Phosphorus is a nutrient essential to the growth of plants and animals,
as well as a raw material for a variety of commercial products. For this rea-
son, phosphorus-derived compounds are produced and consumed in substantial
q~antities. In the course of these human activities, significant quantities
of phosphorus-containing wastes enter the environment as air emissions, aque-
ous effluents, or solid residues.
In addition, a number of natural sources of phosphorus, such as runoff
from undisturbed land areas, weathering of rocks, plant pollens, leaves, etc.,
also contribute to the environmental levels.
In most freshwater lakes and some estuarine ecosystems, the introduction
of excessive quantities of phosphorus transported from any of the aforemen-
tioned sources can promote radical biological and chemical changes in the ex-
isting habitats. A few of the most easily noted changes include increased pro-
duction of aquatic plants, a loss of fish species requiring water with a high
oxygen content, and a general instability within the indigenous plant/animal
community. The sum total of the subsequent water quality alterations is re-
ferred to as eutrophication. The ultimate result is a decline in the value
of the original body of water for recreation, fisheries, or as a municipal
water supply.
Although eutrophication is a complex process with several contributing
factors, a reduction of phosphorus loading is often a prerequisite for the im-
provement of water quality. Identification and quantification of the important
sources of phosphorus release to the environment are the first steps toward
this important goal.
The objective of this task was to conduct an analysis on both a qualita-
tive and quantitative basis of the principal sources (natural and anthropo-
genic) of phosphorus release to the environment. Phosphorus pollutants trans-
ported within a land source without reaching surface waters or discharged to
subsurface waters which are not a part of the surface water inventory are not
considered in this study.
Included in this report is a brief discussion of the terminology and fac-
tors related to phosphorus in the environment and its role in eutrophication.
1
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This brief discussion will include topics such as eutrophication and the role
of phosphorus, septic tanks, the effect of soil type on phosphorus movement,
mechanisms of sediment release of phosphorus, chemical forms of phosphorus and
their environmental fate, point and nonpoint sources, loading rates, and other
factors associated with the discharge of phosphorus and its role in the environ-
ment.
The assessment of phosphorus discharges to the environment includes nat-
ural and anthropogenic, point and nonpoint sources. However, natural sources
will not be discussed in as much detail as other sources, nor will any attempt
be made to quantify these sources. Nonpoint anthropogenic sources are identified
by land use, i.e., urban, forest, fertilized and unfertilized cropland, pasture-
land, etc. All sources are approximately quantified with respect to phosphorus
loadings; the accuracy of these estimated loadings is unknown. No measured phos-
phorus loadings are reported in the quantification study. The estimated amounts
of phosphorus discharged to the environment are based principally on theoreti-
cal values reported in the literature and are calculated rather than measured
quantities. The estimated values have not been validated. For industrial point
sources, each waste stream for all processes in each industry consuming or pro-
ducing phosphorus compounds (by Standard Industrial Classification (SIC) code)
is quantified with respect to phosphorus discharges, including the chemical
form of phosphorus and the fate of the waste stream. Municipal discharges from
sewage treatment plants are evaluated with respect to both human waste and de-
tergent loadings. The result of this assessment will be the identification of
all major point and nonpoint phosphorus discharges and the estimation of quan-
tities associated with each anthropogenic source.
On a regional basis, the State of Florida is evaluated with respect to
phosphorus discharges using the results of the national assessment. The as-
sessment of Florida was chosen to serve as a model for other potential re-
gional assessments. Regional assessments, which are important because of the
variation which can occur in total phosphorus sources, can apply to groups
of states, individual states, counties, or metropolitan areas depending upon
the needs of the study. All sources will be evaluated regarding their appli-
cability to this regional setting and the sources rank ordered. From this
evaluation, the quantity of phosphorus discharge for each applicable point
and nonpoint source can be estimated.
Detergent phosphorus regulations in Indiana and New
in terms of the affected sites (i.e., lakes, reservoirs,
overall water quality impacts of these regulations.
York are discussed
rivers, etc.) and the
The scope of work included the following major segments:
1. Collect the required data base and prepare a comprehensive listing
of all sources of phosphorus, natural and anthropogenic, in the environment.
Describe the mechanism of entry to the environment and evaluate the signifi-
cance of each source.
2
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2. Quantify each principal source identified in Part 1 on
sis and also perform a single regional assessment as an example
value of Part 1 in a regional scheme.
a national ba-
testing the
In all emission estimates shown in this report, the term "phosphorus" re-
fers to the total phosphorus content unless otherwise noted. All data on quan-
tification of phosphorus sources are presented in terms of total phosphorus
(i.e., kilograms (kg) of total phosphorus per metric ton (MT) of product, or
metric tons of total phosphorus per year). One metric ton is equivalent to
1,000 kg or 2,205 lb.
Results o~ this study are presented in subsequent sections of this report,
including summary and conclusions, discussion of methodology, definition and
discussion of terms, identification of phosphorus sources, and quantification
of principal phosphorus sources.
Conversion
dix A. Appendix
calculating the
emission.
factors used in phosphorus terminology are presented in Appen-
B presents typical examples of the estimating methods used in
approximate phosphorus loadings for various point sources of
3
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SECTION 2
SUMMARY AND CONCLUSIONS
A summary of the results obtained in this study is presented in this sec-
tion. Areas include identification and discussion of phosphorus sources, quan-
tification and characterization of principal phosphorus sources, findings for
the state regulations on detergent phosphate in Indiana and New York, and con-
clusions.
IDENTIFICATION OF PHOSPHORUS SOURCES
Phosphorus can be introduced into the
nonpoint sources. The constituents of each
and discus.sed in this study.
environment from either point or
of these sources were identified
Nonpoint Sources
Major sources of nonpoint phosphorus pollutants include runoff from crop-
land, pasture, forests, and rangeland, livestock feedlots, urban areas, and
rural roadways. Agricultural cultivation is a major source of phosphorus wa-
ter pollution. Well-managed pasture and rangeland can provide good cover to
protect soil from erosion. As a result, releases of phosphorus-containing sed-
iment from densely vegetated lands are lower than those for cropland. The term
forestlands comprises a combination of recently harvested forests, logging
roads, undisturbed commercial forest, and noncommercial forests. Uncontrolled
livestock feedlots are sources of concentrated phosphorus-containing wastes.
If improperly managed, these wastes can result in substantial pollution loads.
Urban stormwater may remove phosphorus-containing wastes from both pervious
and impervious surfaces and, thereby, contribute to the phosphorus pollution
of receiving waters. The sources of this pollution in urban areas include soil
erosion, dust and fly ash from industrial facilities, automobile leakage (e.g.,
engine oil and fuel residues), lawn fertilizers, organic debris from tree
leaves and grass trimmings, discarded litter and pet wastes. Runoff from high-
ways and highway rights-of-way contains significant amounts of oil, fuel resi-
dues, dust and dirt, tree leaves, and grass trimmings--all of which are sources
of phosphorus.
Inadvertent nonpoint sources can also account for significant phosphorus
air emissions. These sources include wind-blown soil, fertilizer application,
agricultural burning, and forest fires.
4
-------
Natural phosphorus discharges to surface waters occur independent of hu-
man actions. They include natural air emissions (dust, etc.), "natural runoff"
(i.e., erosion and leaching from undisturbed land), decomposition products
from natural communities such as algae and higher plants, and wastes from wa-
terfowl, fish, and other fauna.
Point Sources
The major point sources of phosphorus discharge result from the mining of
phosphate rock, manufacture of phosphorus-containing compounds, selected uses
of these compounds, and municipal or individual sewage treatment. Discharges
of phosphorus result when the rock is mined, beneficiated, and supplied to
phosphate fertilizer manufacturers and producers of other chemicals.
A majority of the mined rock is utilized in the production of phosphate
fertilizers. The manufacturing sites for each of the fertilizers represent a
point source for phosphorus discharge whereas the release of phosphorus to the
environment from the extensive use in various agricultural applications repre-
sents a nonpoint source of discharge. Relatively large quantities of phosphorus-
based animal feed products are manufactured in the United States. Phosphorus
losses to the abnosphere and to wastewater occur during the manufacture of these
feed supplement products.
The second major use of phosphate rock is the manufacture of phosphorus-
based detergents for home and commercial laundry and cleaning applications. In
this instance, the manufacture and use of the detergents represent a point
source discharge of phosphorus to the environment.
Phosphorus-based chemicals are used in a variety of industrial and home
water treatment applications such as cooling water systems, boiler water treat-
ment, and domestic water treatment systems. In each of these cases, the manufac-
ture of the water treatment chemical and its application represent point SOurces
for the discharge of phosphorus.
Additional industrial consumption of phosphorus is in the production of a
wide variety of phosphorus-derived chemicals such as organophosphorus pesticides,
fuel additives, pharmaceuticals, fire retardant chemicals, and food additives.
The production sites for all of these chemicals represent a potential point
source discharge of phosphorus. Usage of the compound may result in a point or
nonpoint discharge depending upon the specific application.
Municipal sewage treatment effluent is a significant point source of phos-
phorus discharged to the environment. Incoming wastewater to the sewage treat-
ment plant contains phosphorus discharges from home, commercial, and industrial
applications. A portion of the phosphorus is removed by waste treatment and the
remainder is discharged as treatment plant effluent.
5
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Inadvertent point sources, such as iron and steel
duction, refuse incineration, fuel oil combustion, and
contribute to phosphorus pollution.
m~nufacture, cement pro-
coal combustion, also
Domestic production and apparent consumption of phosphorus in 1975 were
obtained from the literature. Industrial contacts and data in the technical
literature indicate that the figures are also applicable for 1978. The use
patterns show that agricultural applications (including fertilizers and ani-
mal feeds) account for 83% of total phosphorus consumption. The manufacture
of other phosphorus chemicals, including sodium tripolyphosphate and calcium
phosphates, represents an additional 9% of total phosphorus consumption. These
two groups, which account for about 92% of total consumption, are considered
to include all principal industrial point sources of phosphorus. There are
many miscellaneous phosphorus-based chemicals which, taken together, represent
only a few percent of the total phosphorus consumption. A complete source as-
sessment for each of these chemicals was beyond the scope of this task. The
emphasis in this study was placed on the identified principal point sources
and a few minor Sources of phosphorus to the environment. The principal point
sources investigated were:
*
Agricultural products
Wet process phosphoric acid and phosphate fertilizers (SIC No.
2874)
Animal feed products (SIC No. 2048)
*
Industrial products
Elemental phosphorus, phosphoric acid (dry process), and ferro-
phosphorus (SIC No. 2819)
Phosphorus pentoxide, phosphorus trichloride, phosphorus oxychlo-
ride, and phosphorus pentasulfide (SIC No. 2819)
Detergent builders (SIC No. 2841)
Detergent formulation (SIC No. 2841)
Water treatment chemicals (SIC No. 2899)
Food grade calcium phosphate (SIC No. 2048)
Direct acid (H3P04) treatment of metals (no SIC number)
*
Municipal sewage treatment effluent
*
Inadvertent sources
6
-------
The term, inadvertent sources, refers to miscellaneous manufacturing and
product use activities which account for significant phosphorus losses to the
environment but are generally unrelated to phosphorus-based industries or nat-
ural phosphorus sources. Examples are the manufacture of iron, steel, and ce-
ment, combustion of fuel oil and coal, wind-blown soil, agricultural burning,
and forest fires.
QUANTIFICATION OF PRINCIPAL PHOSPHORUS SOURCES
Estimates of total phosphorus emissions were developed for each identified
principal source (and some minor sources) on a national basis and for a selected
region. The regional assessment was developed to serve as a model for possible
assessments in other regions.
Data required in this study on nonpoint source phosphorus loading for run-
off to surface waters were taken from the report, "National Assessment of Water
Pollution from NonpointSources." Air emissions from nonpoint sources were es-
timated using data available in the literature.
Point source emissions were estimated on the basis of model flow diagrams
and phosphorus material balances developed from data in the technical literature.
Results of the analysis of phosphorus sources in the environment described
in this report show that the estimated national phosphorus emissions to air and
water for 1978 are on the order of 2.9 million metric tons (1 MT = 1,000 kg =
2,205 lb). Of this total, 87.6% was attributable to nonpoint sources--princi-
pally cropland runoff (~ 49%), pasture and rangeland runoff (~34%), and forest-
land runoff (3%). About 99.3% of the total nonpoint discharge comes from runoff
water, with 0.7% attributable to air emissions from inadvertent sources.
Point sources account for about 12.4% of total national emissions or about
360,000 MT/year of phosphorus discharged. Municipal sewage treatment effluent
represents the largest single contributor to this category (10.6%). The second
and third ranking sources, in terms of emission magnitude, are water treatment
chemicals (0.8%) and inadvertent sources (0.4%).
Total estimated point source air emissions account for about 55% of the
47,700 MT of phosphorus released to the atmosphere each year in the United
States. (This value is included in the total national emission.) The remainder
(45%) is from nonpoint air emissions. The estimated quantity of phosphorus in
solid wastes is relatively small (32 MT/year).,
The 10 largest 1978 national sources of phosphorus release are estimated
as follows:
7
-------
Emission source category
Estimated % of
national phos-
phorus discharge
Type of source,
point (P) or
nonpoint (NP)
1.
2.
3.
Cropland runoff
Pasture and rangeland runoff
Municipal sewage treatment
effluent
Forestland runoff
Total inadvertent sources
Livestock feedlots
Phosphorus-based water treat-
ment chemicals (usage)
Urban runoff
Phosphate rock mining and
beneficiation
Production of phosphorus and
chemicals
48.9
33.6
10.6
NP
NP
P
2.9
1.1
1.0
0.8
4.
5.
6.
7.
NP
P + NP
NP
P
0.6
0.2
8.
9.
NP
P
0.2
10.
P
Total
99.9
Regional assessments are important because of the variation in total phos-
phorus sources which can occur from one region to another. These regional as-
sessments can be for groups of states, individual states, counties, or metro-
politan areas, depending upon the needs of the study. The methodology shown
for the assessment of Florida can serve as a model for other regional assess-
ments.
For the selected regional study (Florida), the estimated total phosphorus
emission is about 34,000 MT/year or about 1.2% of national emissions.
The total nonpoint emissions in Florida represent about 57% (~ 19,500 MT)
of the total estimated phosphorus emission for the state. In this category,
runoff water discharges account for about 56% of total emissions, with about
1% attributable to inadvertent nonpoint sources.
The estimated total emission from point sources in Florida amounts to
about 14,600 MT of phosphorus or approximately 43% of the entire statewide
discharge. The largest point source discharges are municipal sewage effluent
(21%), phosphate rock mining and beneficiation (10.7%), production of animal
feed (~5%), and production of phosphate fertilizer and intermediate chemicals
(4.2%). Inadvertent point discharges account for about 1.2%. of the total for
the state.
The estimated 10 largest environmental phosphorus pollution sources in
Florida in terms of total phosphorus discharge are:
8
-------
Estimated % of Estimated 10
Type of Florida phos- of national
Emission source category source phorus discharge discharge~\-
1. Pasture and rangeland NP 37.9 33.6
runoff
2. Municipal sewage treat- P 21.0 10.6
ment effluent
3. Cropland runoff NP 13.7 48.9
4. Phosphate rock mining P 10.7 0.2
beneficiation
5. Anima 1 feed production P 4.8 1.0
(feed grade calcium
phosphates and de-
fluorinated phosphate
rock)
6. Phosphate fertilizer and P 4.2 0.2
intermediate chemical
production
7. Forestland runoff NP 2.4 2.9
8. Inadvertent sources P + NP 2.3 1.1
(total)
9. Urban runoff NP 1.5 0.6
10. Use of phosphorus-based NP + P ....Qd ~
water treatment chem-
icals
Total 99.2 99.9
~\- Percent for emission source category.
The distribution of phosphorus discharges in Florida thus seems to be
quite different from that at the national level. For example, in the national
assessment the ratio of total nonpoint to point emissions is about 7 to 1. In
contrast, for Florida the estimated nonpoint to point source emission ratio
is about 1.3 to 1. The cropland runoff emissions are 48.9% of the total in the
national assessment and only 13.7% of the total for Florida.
A contrast also exists in the distribution of point source discharges at
the national and Florida levels. On a national basis, municipal sewage efflu-
ent accounts for about 10.6% of the total phosphorus discharge; in Florida the
sewage effluent accounts for 21% of total phosphorus discharge. Phosphate rock
mining and processing and fertilizer and animal feed production in Florida
represent a much higher proportion of total phosphorus discharge than in the
case of the national assessment (about 20% in Florida versus 0.4% for the
9
-------
nation). These differences point out the difficulty in applying ~ational phos-
phorus emission figures to regions or loca l.i ties.
In some regional settings, phosphorus sources that are minor on a national
scale may take on major significance, e.g., discharge of municipal sewage plant
effluents into an urban lake. Thus, for regional studies of phosphorus sources,
the high potential for these special pollution problems should be recognized.
Cognizance should also be given to the special demand and usage of small volume
phosphorus-containing chemicals in certain regions of the United States. For
example, the concentrated use of the stable aryl phosphates as fire retardant
hydraulic fluids in metropolitan areas may lead to significant contamination
of receiving waters because of leakage or disposal.
ANALYSIS OF DETERGENT PHOSPHATE LEGISLATION IN INDIANA AND NEW YORK
A cursory analysis was conducted of detergent phosphate controls in the
states of Indiana and New York. This study addressed the surface water geogra-
phy, the location and nature of phosphorus water quality problems, and the im-
pact of the detergent phosphate control.
The principal findings of this study were:
1. Sewage treatment effluents are the major point source of phosphorus
loading in these states.
2. A significant portion of the aquatic habitat in Indiana and New York
contained phosphorus at levels (> 25 ~g/liter in lakes and reservoirs, > 50
~g/liter in rivers emptying into reservoirs, and> 100 ~g/liter in free flow-
ing rivers) which indicated eutrophic conditions prior to the 1973 legislation.
3. Phosphorus loading on Indiana rivers decreased by about 20% during the
first 2 years of the state's detergent phosphate ban.
4. Despite the improvement noted, major segments of the Wabash, White,
and Grand Calumet rivers in Indiana remained eutrophic (> 100 ~g/liter of total
phosphorus) 2 years after the detergent ban was initiated. As noted previously
in Item 1, sewage treatment effluents are major point sources of phosphorus
loading. The flushing action provided by high water flows and the rarity of
anaerobic conditions in rivers tends to minimize the possibility that sediment
release might have sustained high phosphorus levels. However, the present data
for rivers in Indiana are inconclusive with respect to the cause of the current
phosphorus levels. For lakes in Indiana, the shortage of data precludes any
conclusions to be drawn.
5. The available data
phorus loading reduction in
phosphate ban. Data on file
are insufficient to permit an analysis of the phos-
New York as a result of the statewide detergent
with the New York State Environmental Conservation
10
-------
Department, which records effluent parameters of the National Pollution Dis-
charge Elimination System (NPDES) permittees, have not been sufficiently com-
piled to allow the determination of any changes in phosphorus loading. Also,
MRI is not aware of any additional studies to duplicate the lake sampling of
the National Eutrophication Survey. Such an effort would quantify any improve-
ments in lake/reservoir water quality which may have occurred since the enact-
ment of the phosphate legislation.
CONCLUSIONS
1. On a national basis, nonpoint sources (principally cropland or pasture
and rangeland) apparently account for about 88% of all phosphorus emissions
discharged to the environment. The effective control of these nonpoint sources
would drastically reduce phosphorus loadings to the nation's surface waters. A
critical factor. in the limitation of nonpoint phosphorus discharge to the envi-
ronment is the improved management of agricultural and other developed land to
minimize phosphorus pollution caused by runoff.
2. A comparison of regional (Florida) and national emissions of phosphorus
demonstrates that national control of phosphorus is likely to be inappropriate
in some cases. Therefore, phosphorus emission control schemes which address re-
gional activities would (if implemented) probably be more effective than na-
tional control methods. Localized and regional problems should be assessed in-
dividually.
3. Achievement of improved municipal sewage treatment for phosphorus re-
moval appears to be an important priority leading to water quality improvement,
with respect to those regional settings where these effluents are a major source
of phosphorus loading to lakes.
4. Certain apparently minor sources of phosphorus losses on a national
basis may take on major significance in individual regional settings (e.g.,
specific metropolitan areas) because of unusually heavy concentrations of pro-
ducers and/or consumerS of phosphorus-based chemicals. An example case is pol-
lution of an urban lake by phosphorus contained in industrial discharges. Care
must be exercised in assessing phosphorus emissions on a local or regional
level to avoid overlooking these problems.
5. Atmospheric pollutants (i.e., particulate matter) containing phosphorus
can be an important source of phosphorus loading in surface waters. It has been
reported that this source contributed one-fifth to one-third.of the total phos-
phorus entering Lake Michigan in 1974.
11
-------
SECTION 3
DISCUSSION OF METHODOLOGY
A discussion of the methodology used for the data acquisition and quanti-
fication of phosphorus sources is provided in this section.
DATA ACQUISITION AND ANALYSIS
Initially, the U.S. Environmental Protection Agency (EPA) provided a se-
ries of technical articles related to this task. Information contained in
these articles concerned the breakdown of total phosphorus loadings to surface
waters. All summaries and abstracts in these articles and documents were re-
viewed and, as appropriate, utilized in this study.
Literature Search Activities
A number of data sources were investigated as a means for supplementing
the above data base. Published data pertaining to industrial sources of phos-
phorus release were obtained from the following technical documents:
--k
. 1/
Encyclopedia of Chem1cal Technology.-
Chemical and Process Technology Encyclopedia.l/
-,':
'k
d . J/
Chemical Process In ustr1es.-
-k
Industrial Chemicals.~/
-;':
Directory of Chemical producers.2/
Chemical Economics Handbook (Phosphorus Chemicals~/ (1975, 1976,
1977) .
~'c
.k
Annual reports and workshop proceedings of the International Joint
C . . 7- 9/
OITm1SS10n.-
A search was made of computerized data in the files (DIALOG) of the Na-
tional Technical Information Service (NTIS) using keyword descriptions. Sub-
ject areas covered in this search included phosphorus release to the
12
-------
environment by air emissions, wastewater effluent, solid wastes, and septic
tank systems. A computerized search of Dissertation Abstracts was employed to
identify current research findings on nonpoint phosphorus loading from agri-
cultural sources. This search surveyed all Ph.D. theses entering the data file
during the last 10 years for selected keywords. A limited amount of useful in-
formation was identified by these searches.
Telephone and Letter Inquiries
Numerous telephone and letter contacts were made with governmental agen-
cies (state and national), trade organizations, and industry sources to iden-
tify and collect available data relating to the qualification and quantification
of point sources (both municipal and industrial) of phosphorus release to sur-
face waters. Information was obtained on potential methods of data retrieval,
technical articles of interest, waste management practices, and probable data
gaps. With few exceptions, most of the information acquired was of a general
nature and very few quantitative data were obtained. The contacts were generally
reluctant to divulge any detailed information on discharged process wastes.
Telephone inquiries concerning phosphorus loading from agricultural sources
were made to various departments of the agricultural colleges of Iowa State Uni-
versity, the University of Nebraska, Kansas State University, the University of
Wisconsin, and the Potash and Phosphorus Institute. Little useful data were ob-
tained from these sources.
Computer-Based Data Retrieval Systems
The feasibility of acquiring useful phosphorus pollution data from the EPA
STORET system under the National Pollution Discharge Elimination System (NPDES)
program was searched for industrial plants discharging effluent into navigable
waterways. A trial search of this system, through the cooperation of the EPA
Region VII office (Kansas City), was made for the years 1975 and 1976. MRI as-
sisted in the selection of keywords for this search. The results showed that
very little point source data were available. The NPDES program is a source
of effluent data on phosphorus for those permits which specify it. However,
since few industrial permits specify this material, individual discharges are
difficult to trace even for those industries discharging phosphorus to a mu-
nicipal treatment plant that regularly reports phosphorus. It was concluded
that this system could not provide the required point sOUrce data for this
study.
Another potential alternative data source is the discharge monitoring
and permit compliance information compiled by state pollution control agencies.
Telephone inquiries relating to the use of these data sources were made to the
states of Florida, Louisiana, Texas, Kansas, Missouri, Arkansas, Iowa,
Michigan, and New Jersey. Four of these states (Arkansas, Iowa, Missouri, and
Kansas) had no data or very little infbrmation on phosphorus sources. The
-------
remaining states indicated that visits to their offices would be necessary for
data review and compilation. It was concluded that it would not be feasible to
collect information by this procedure.
EPA Data on Effluent Limitation Guidelines
A review was made of the available EPA development documents on effluent
limitation guidelines for new source performance standards for applicable point
source discharges of industries of interest to this program. New source perfor-
mance standards for applicable industries were also reviewed. The subject areas
reviewed in these documents were:
;'~
. 10/
Minerals for the Chemical and Fertilizer Industr~es,--
(Ie
h . 1 11/
Basic Fertilizer C em~ca s,--
ok
Phosphorus Derived Chemicals ,11/ and Draft supplement,l1/
*
. 14/
Other Nonfertilizer Phosphate Chem~cals,--
-k
15/
Soap and Detergent,-- and
~I:
16/
Animal Feed, Breakfast Cereal, and Wheat Starch.--
QUANTIFICATION OF PHOSPHORUS SOURCES
The quantification consisted basically of a study of two major subcate-
gories of phosphorus emissions: nonpoint sources and point sources of dis-
charge to the environment. The nonpoint sources are those which result in dif-
fuse discharges, while point sources are those which discharge phosphorus from
discrete, measurable points.
The quantification studies were essentially limited to the principal
sources identified in the early phases of this study.
Nonpoint Sources
A recent draft report, "National Assessment of Water Pollution From Non-
point Sources,'~/ discusses the results of a study by MRI which quantita-
tively assessed various nonpoint pollutant loads (including phosphorus) for
the United States. A pub 1i shed companion report, "Loading Functions for As-
sessment of Water Pollution From Nonpoint Sources,u18/ discusses the develop-
ment and use of loading functions for determining nonpoint loads (including
phosphorus). The phosphorus-loading functions cover runoff discharges from
the following sources: (a) cropland, (b) pasture and rangeland, (c) forest-
land, (d) livestock feedlots, (e) urban areas, and (f) rural roadways. Infor-
mation taken from these two reports served as the data base for quantifying
the nonpoint phosphorus loading in this study.
14
-------
Emissions for sources (a) through (c) were calculated by an approach in
which the estimated quantities of phosphorus contained in eroded sediments
were summed for each source. The basic formula used was the Universal Loss
Equation.12/ The basic emission estimating method used for livestock feedlots
consisted of a method to estimate feedlot runoff from precipitation character-
istics of a region and data on phosphorus concentrations in runoff and feedlot
sizes. For urban runoff estimates, the basic information source was several
studies on the rates of deposition of phosphorus-containing pollutants in rep-
resentative urban areas and other data on the rates of delivery of phosphorus
in runoff. A more detailed discussion of the methodology for estimating non-
point phosphorus loading is presented in Section 6.
There are a number of other current technical reports dealing with non-
point phosphorus loading and assessments of phosphorus discharge. A brief dis-
cussion of some noteworthy reports, which were reviewed and referenced in this
study, follows.
A recent investigation by the Corvallis Environmental Research Laboratory,20/
"Nonpoint Source--Stream Nutrient Level Relationships: A Nationwide Study,"
includes data on nonpoint phosphorus loads. Stream nutrient runoff and watershed
characteristics for 923 nonpoint source watersheds acrosS the nation were ana-
lyzed.
Some of the most comprehensive, localized activity on phosphorus aSsess-
ment has occurred in connection with the Canada-U.S. Great Lakes Water Quality
Agreement. Annual reports from the International Joint Commission's Great Lakes
Water Quality Board~/ Reference Group on Great Lakes Pollution From Land Use
Activities,~/ and the Research Advisory Board2/ contain considerable informa-
tion on nonpoint phosphorus discharge in the Great Lakes area.
In 1976, J. H. Gakstatter and associates reported on the results of a sur-
vey by the EPA, "Lake Eutrophication: Results From the National Eutrophication
Survey. ,,21/
The U.S. Geological Survey has
Phosphate Resources in Southeastern
mental impact statement.
reported recently on the '~evelopment of
Idaho."22/ This includes a final environ-
Point Sources
Effluents from municipal sewage treatment plants are a point source of
phosphorus discharge. Estimates of these discharges were developed on the ba-
sis of annual per capita phosphorus loads (including inputs from laundry de-
tergents, automatic dishwashers, garbage disposals, and personal sewage) and
on estimated phosphorus inputs from commercial establishments and industry.
The 1976 Needs Survey.23/ was used to obtain information on the population
15
-------
served by primary, secondary, and tertiary sewage treatment facilities (ex-
cluding the nonsewered population). A detailed discussion of the estimating
methods used for quantifying phosphorus loads in treated sewage effluent is
presented in Section 6.
To the extent possible, industrial discharges were quantified on the ba-
sis of models developed for production or use processes. Representative pro-
cess flow diagrams include phosphorus balances and available data on unit
emission rates for phosphorus. Supporting data used to develop these model
process flow sheets and accompanying descriptions were taken largely from EPA
effluent limitations guidelines,lO-16/ a report on the inventory of sources
and emissions of phosphorus,24/ and industrial contacts.
These process diagrams show, wherever possible, the phosphorus balance,
losses, and chemical forms present in each waste stream for each product of
interest. In addition, the process diagrams indicate the fate of the waste
streams (atmosphere, water, landfill, etc.).
For each industrial process diagram, unit phosphorus emission factors,
based on the production rate of 1 MT of product, were developed. These emis-
sion factors applied to (a) discharges of total phosphorus in process waste-
water effluent per metric ton of product and (b) discharges of total phosphorus
in air emissions per metric ton of product.
The application of these unit emission factors requires the use of produc-
tion or consumption rate data for products of interest. Since the published
rate data were not current, the production/consumption rates were adjusted us-
ing growth trend data obtained from technical publications or from industry
contacts.
For the national assessment, the total annual production/consumption
for the products of interest (e.g., elemental phosphorus production) were
tiplied by the emission factors derived from the appropriate process flow
gram.
rates
mul-
dia-
. 25/
In addition, reported data on national inadvertent po~nt source&--
updated by using 1978 production/consumption rate trend factors.
were
Appendix A lists conversion factors used in phosphorus terminology. Ap-
pendix B presents descriptions of typical methodology used to calculate the
estimated total phosphorus emission from industrial point sources.
16
-------
REFERENCES TO SECTION 3
1.
Anonymous. Kirk-Othmer Encyclopedia of Chemical Technology. Second Edi-
tion, Volume 15, Interscience Publishers, 1963. pp. 257-291.
2.
Anonymous. Chemical and Process Technology Encyclopedia. D. M. Considine,
Editor-in-Chief. McGraw-Hill, 1974. pp. 868-875, 1141-1146.
3.
Shreve, R. N., and J. A. Brink. Chemical Process Industries. Fourth Edi-
tion, McGraw-Hill, 1977. pp. 244-261.
4.
Lowenheim, F. A., and M. K. Moran. Industrial Chemicals. Fourth Edition,
Wiley-Interscience, 1975. pp. 628-657, 746-754~
5.
Stanford Research Institute. Directory of Chemical Producers - USA. 1977
Edition, Menlo Park, California, 1977.
6.
Stanford Research Institute. Chemical Economics Handbook. Menlo Park,
California, 1975, 1976, 1977. (This is a client-private service of SRI's
Chemical Information Services Department, available on a subscription
basis only.)
7.
Great Lakes Water Quality Board. 1976 Annual Report submitted to the In-
ternational Joint Commission. July 1977.
8.
International Reference Group on
tivities. Joint Summary Report -
mission. September 1977.
Great Lakes Pollution From Land Use Ac-
Task B to the International Joint Com-
9.
Great Lakes Research Advisory Board. Annual Report to the International
Joint Commission. July 1977.
10.
Environmental Protection Agency. Minerals
Industries. Volume II, Mineral Mining and
l-75/059b (Group II), Office of Water and
D.C., October 1975.
for the Chemical and
Processing Industry.
Hazardous Materials,
Fertilizer
EPA 440/
Washington,
11.
Environmental Protection Agency. Basic Fertilizer Chemicals Segment of the
Fertilizer Manufacturing. EPA 440/l-74/0lla, Office of Air and Water Pro-
grams, Washington, D.C., March 1974.
12.
Environmental Protection Agency. Phosphorus Derived Chemicals. EPA 440/1-
74/006a, Office of Air and Water Programs, Washington, D.C., January 1974.
13.
Environmental Protection Agency. Draft Supplement to Reference 12. EPA
Contract No. 68-01-3289, Office of Water and Hazardous Materials,
Washington, D.C., October 1977.
17
-------
14.
Environmental Protection
EPA 440/1-75/043a (Group
rials, Washington, D.C.,
Agency. Other
I, Phase II),
June 1976.
Non-Fertilizer Phosphate Chemicals.
Office of Water and Hazardous Mate-
15.
Environmental Protection Agency. Soap and Detergent Manufacturing. EPA
440/1-74/18, Office of Air and Water Programs, Washington, D.C., December
1973.
16.
Environmental Protection Agency. Animal Feed,
Starch. EPA 440/1-74/039, Office of Water and
Washington, D.C., September 1974.
Breakfast Cereal, and Wheat
Hazardous Materials,
17.
McElroy, A. D., J. W. Nebgen, A. D. Aleti, and S. Y. Chiu. National As-
sessment of Water Pollution From Nonpoint Sources. Draft Final Report,
EPA Contract No. 68-01-2293, u.S. Environmental Protection Agency,
Washington, D.C., 1975.
18.
McElroy, A. D., S. Y. Chiu, J. W. Nebgen, A. D. Aleti, and F. W. Bennett.
Loading Functions for Assessment of Water Pollution From Nonpoint Sources.
EPA 600/2-76/151, U.S. Environmental Protection Agency, Washington, D.C.,
1976.
19.
Wischmeier, W. H., and D. D. Smith. Predicting Rainfall--Erosion Losses
From Cropland East of the Rocky Mountains. Agriculture Handbook 282, U.S.
Department of Agriculture, Agriculture Research Service, May 1965.
20.
Omernik, J. M. Nonpoint Source--Stream Nutrient Level Relationships: A
Nationwide Study. EPA 600/3-77/105, U.S. Environmental Protection Agency,
Corvallis, Oregon, 1977.
21.
Gakstatter, J. H., M. O. Allum, and J. M. Omernik. Lake Eutrophication:
Results From the National Eutrophication Survey. In: Water Quality Cri-
teria Research of the Environmental Protection Agency. Proceedings of an
EPA-sponsored Symposium. EPA 600/3-76/079, Ecological Research Series,
July 1976.
22.
Department of the Interior, U.S. Geological Survey. Development of Phos-
phate Resources in Southeastern Idaho. Final Environmental Impact State-
ment (FES 77-37), September 1977.
23.
Municipal Construction Division of U.S. Environmental Protection Agency
(EPA 430/9-76-010, 430/9-76-011, and 430/9-76-012), Cost Estimates for
Construction of Publicly-Owned Wastewater Treatment Facilities--1976
Needs Survey, Washington, D.C., 1976.
24.
GCA Corporation. National Emissions Inventory of Sources and Emissions
of Phosphorus. EPA 450/3-74/013, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, 1973.
18
-------
25.
Murphy, T. J. Sources of Phosphorus Inputs From the Atmosphere and Their
Significance to Oligotrophic Lakes. UILU-WRC-74-0092, Water Resources
Center, University of Illinois at Urbana-Champaign, Urbana, Illinois,
November 1974.
19
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SECTION 4
DEFINITION AND DISCUSSION OF TERMS
INTRODUCTION
This section provides a discussion of technical terms associated with phos-
phorus, its transport in the environment, and implications for eutrophication.
Specific chemical forms of phosphorus and associated parameters are discussed.
A distinction is made between point and nonpoint sources with major point
sources in the phosphorus industry being categorized by SIC codes. Other dis-
cussions focus on the availability of phosphorus as a nutrient and the chemis-
try of phosphorus movement in soils and sediments. Because of the importance
of sewage-related phosphorus, septic tanks and municipal sewage treatment sys-
tems are discussed.
EUTROPHICATION
Eutrophication is the process by which waters become enriched with nutri-
ents. The primary manifestation of eutrophication is the acceleration of algal
biomass production. This increase in the growth of aquatic plants and the re-
sulting ecosystem alterations, collectively labeled "eutrophication," most fre-
quently takes place in lakes and reservoirs, but may also be observed in back-
waters and sloughs of rivers and in portions of estuaries.1-41
Eutrophication may occur at a slow rate as nutrients derived from an un-
disturbed watershed fertilize progressively larger crops of algae over a period
of thousands of years. Alternately, the trophic state of a body of water may
remain the same for hundreds of years and not become "eutrophic"--as long as
nutrient input does not exceed losses--or the nutrient loading can actually
decrease with time in rare cases.]1 However, the enrichment process may also
take place rapidly due to nutrient contributions from human, ~rban, agricul-
tural, or industrial activities (cultural eutrophication).1-4
The key nutrient in the eutrophication of most fresh waters is phosphorus
in the form of orthophosphate. Phosphorus is one of about 21 nutrients that
may be required for algal growth. According to Liebig's Law of the Minimum,
any of the 21 essential nutrients will become growth-limiting if present in
the shortest supply relative to the amount needed. Phosphorus is the limiting
nutrient in most lakes.l-SI
20
-------
Exceptions to this last statement include waters that exhibit a naturally
occurring deficiency of some other nutrient, or waters that receive phosphorus
in uncommonly high amounts. The latter circumstance is sometimes observed in
eutrophic lakes. In these cases, nitrogen frequently becomes the limiting nu-
trient--not because nitrogen is in short supply, but because phosphorus and
other nutrients are present in excess~1
Both carbon and nitrogen are required in larger quantities than ~70sphorus
for plant growth and reproduction (ratio of atoms--C:N:P ~ 106:16:1),- but
they are both readily available to aquatic ecosystems via the solubility of
atmospheric C02 and N2. In addition, blue-green algae are capable of fixing
atmospheric nitrogen. Since phosphorus has no such atmospheric reservoir, it
is usually the limiting nutrient in lakes undisturbed QY man; this is also the
reason whl phosphorus is generally considered to be the most easily controlled
nutrient.-I
When phosphorus is the limiting nutrient in a lake, eutrophication may
be controlled--in many instances--by restricting the inflow of this nutrient.
However, in lakes which have reached advanced stages of eutrophication prior
to the implementation of phosphorus control measures, recycling of orthophos-
phate from hypolimnetic* .water during seasonal overturns (usually spring and
autumn) may sustain problem algal growth. Because of this self-fertilization
process, the duration of the waiting period between nutrient loading reduc-
tions and measurable improvements is hard to predict. This time lag has been
hypothesized to appro~imate three times the phosphorus residence time of the
given body of water.l
In different aquatic ecosystems, eutrophic conditions must be characterized
separately. Lakes and storage reservoirs (which are, in effect, man-made lakes)
are similar in their response to nutrient loading. Major parameters used to in-
dicate eutrophic conditions in lakes and reservoirs include: total phosphorus
> 25 ~g/liter, chlorophyll> 10 ~g/liter, Secchi disc visibility < 2.0 m, and
< 10% hypolimnetic dissolved oxygen saturation-ZI
This terminology is not normally applied to un dammed rivers, but slow-
moving portions of rivers that mimic ponds or small lakes can be affected by
nutrient enrichment. Geologically and biologically, the life cycle of a river
is different from that of a lake. The flushing action of high water conditions
and the ability to meander preclude the death of a river by sedimentation. Natu-
ral flowing waters contain plant and animal life which contrasts sharply with
that present in lakes. Whereas it is not uncommon for eutrophic lakes to sup-
port vast populations of both attached and free-floating algae, the river en-
vironment usually does not allow this degree of problem growth. The motion of
*
The hypolimnetic water (or hypolimnion) is the deep zone in a thermally
stratified lake.
21
-------
stream water is well suited to some species of attached algae but discourages
many others and practically eliminates macroPhytes.~8,9/ However, rivers be-
low major impoundments contain a plankton that reflects that of the impound-
ment.
Many rivers carry large sediment loads, particularly during spring thaws
or rainy seasons. Light penetration is greatly limited by the amount of sus-
pended sediment, and the potential for plant growth is reduced. In addition,
the erratic changes in water level which characterize rivers allow only the
most hardy species of aufwuchs** to survive. As a result, a river habitat may
provide only a narrow zone near the water surface and along the shoreline suit-
able for the growth of algae and macrophytes, and the productivity/of this
shoreline zone may be further reduced by water level fluctuation.~
Recent water quality criteria recommendations by the EPA have taken into
account the inherent differences between lake and river habitat response to
phosphorus loading. Because rivers are less susceptible than lakes to eutro-
phication and its associated problems, higher levels of dissolved phosphorus
are considered tolerable in rivers. The level of total phosphorus (as phosphorus)
not to be exceeded in rivers is 100 ~g/liter. At any point where a river enters
a reservoir, the recommended limit is lowered to 50 ~g/liter. Within lake or
reservoir basins, the figure is 25 Ilg/liter..lQ/
Estuaries also must be considered separately in a discussion of eutrophi-
cation. Permissible phosphorus concentrations determined for lake, reservoir,
or river habitats are not applicable. In/phosphorus-limited estuaries (many
estuaries are not phosphorus limite~ ), benthic oxygen depletion has been
postulated to reach critical levels as a result of total phosphorus concentra-
tions higher than ~55 ~g/liter during the summer or ~ 80 ~y/liter during the
winter in estuaries located in northern temperate climates.-1/
The hazard of nutrient enrichment in an estuary is due largely to the
high retention of nutrients characteristic of estuaries. The mechanism of this
nutrient retention may be explained as follows. As the less dense surface layer
of fresh water flows seaward, it drops much of its nutrient-rich sediment. An
opposite flow of more dense deeper sea water returns these sediments back into
the estuary. Tidal fluctuations and river currents further complicate this gen-
eral description of estuary circulation in different locales; however, the com-
mon phenomenon seen is a nutrient-rich zone where biological productivity is
higher than either the adjacent ocean or fresh water.2/
~'(
Macrophytes are aquatic plants that are large enough to be observed with
the unaided eye (in contrast to the many species of microscopic phyto-
plankton) .
Aufwuchs consists of generally small plants or animals attached to any sub-
merged substrate.
-k-k
22
-------
When nutrients provided by fresh water entering an estuary become exces-
sive, the results are similar to those seen in eutrophic lakes. The standing
crop of algae increases, decomposition of the resulting biomass accelerates,
benthic* organisms experience oxygen shortages, and the ecosystem is generally
disrupted. Because estuaries provide a necessary habitat for many shellfish
and fish fry, as well as a pathway for the spawning runs of some species of /
fish; these conditions have serious repercussions for commercial fisheries.2
General symptoms of eutrophication in all bodies of water include: (a)
a decrease in phytoplankton diversity; (b) an increase in phytoplankton pro-
duction; (c) changes in species composition of aquatic organisms, such as a
shift to blue-green algae and rough fish species; (d) a decrease in the trans-
parency of water; (e) the depression of oxygen concentration in the hypolimnia
of lakes during periods of stratification; (f) the buildup of total phosphorus
and nitrogen concentrations; and (g) an increase in the growth of dense float-
ing algal mats.13,14/
f h... 1 d 13, 14/
Adverse consequences 0 eutrop ~cat~on ~nc u e:
-1:
Interference with recreational and aesthetic uses of surface waters.
./(
Odor, taste, and filtration problems in domestic water supplies caused
by algal blooms.
-/,
Increased cost for water treatment (domestic and industrial water sup-
plies).
*
Problems with agricultural uses of water (obstructions in irrigation
canals, etc.).
ok
Toxicity of some blue-green algae to wild and domestic animals.
('(
Elimination of valuable game and commercial fish species and associated
industries.
~'~
Cost for the cleanup of eutrophic waters.
il:
A decline of property values in water-based communities.
PHOSPHORUS ANALYSES
Types of Phosphorus
Phosphorus may be reported in 12 different analytical forms in studies
of eutrophication problems.l1/ These forms are noted in Table 4-1.
if,
Benthic means indigenous to the bottom.
23
-------
1___-
TABLE 4-1.
FORMS OF PHOSPHORUS REPORTED IN ANAL „TICAL MEASUREMENTS
Form No.
phosphorus material
1
Total phosphorus
2
Total dissolved phosphorus
Phosphorus [in suspended solids~/ (insoluble)
3
4
Phosphorus [in particulates (mud)~/
5
Total hydrolyzable phosphorus (polyphosphorus +
some organic phosphorus)
6
Dissolved hydrolyzable phosphorus
7
Insoluble hydrolyzable phosphorus
8
Total organic phosphorus (phosphorus incorporated
into animal and plant detritus
9
Dissolved organic phosphorus (natural organic
waste, fecal material, etc.)
10
Insoluble organic phosphorus (natural organic
waste, fecal material, etc.)
11
Dissolved orthophosphate (P04-3, H2P04-l, HP04-2,
and ions of polyphosphoric acids)
12
Insoluble orthophosphate (apatite, and inorganic
complexes)
2./
pg. 249: "... [methods] may not be applicable to sediment-type sam-
ples, . . . but. . . data. . . not available at this time to warrant
such usage when [p contents] are required."
Source:
Reference 15.
24
-------
.
~-_._- - --
"Total phosphorus" includes all analytically detectable forms of phos-
phorus. Dissolved or soluble phosphorus includes organic and inorganic phos-
phates that are available as plant nutrients. Dissolved phosphorus has the
most direct impact on eutrophication~/ Phosphorus may also be adsorbed onto
insoluble suspended solids. Phosphorus in particulates (mud) are those solids
found in lake or river bottom sediments. These particulates are not immedi-
ately available as plant nutrients; however, they do represent an inventory
of stored phosphorus which can be released by acidic chemical reactions and
aerobic biological activity. Hydrolyzable phosphorus includes compounds that
can be chemically decomposed by breaking a bond and adding the elements of wa-
ter. Hydrolysis of phosphorus compounds can have a significant effect on eu-
trophication. For example, hydrolysis of polyphosphate compounds (e.g., from
laundry detergents) can result in the soluble orthophosphate forms that are
readily available as a plant nutrient. The soluble orthophosphate form is
sometimes referred to by analytical chemists and by researchers as soluble
reactive phosphorus.
Methods for Chemical Analysis of Phosphorus
Analytical methods covering all forms of phosphorus are discussed in an
EPA document~/ The basic analytical techniques are discussed briefly herein,
and the reader is referred to this document for more detailed information.
The two basic analytical methods for total phosphorus are: (a) the sin-
gle reagent method, which is usable in the 0.01 to 0.5 mg total phosphorus
per liter range; and (b) the automatic colorimetric ascorbic acid reduction
method which is applicable in the 0.001 to 1.0 mg total phosphorus per liter
range.12/ Both methods are based on reactions that are specific for the ortho-
phosphate ion and on the use of colorimetric techniques. Only orthophosphate
phosphorus is measured by these colorimetric techniques. The methods are very
similar and differ principally in the type of equipment used in the analyti-
cal measurements~ As indicated in Figure 4-1, determinations can be made on
the total sample as well as on the filtrate from filtered samples.
The automatic colorimetric method can be summarized as follows.12/ Am-
monium molybdate and antimony potassium tartrate react in an acid medium with
dilute solutions of orthophosphorus to form'an antimony-phospho-molybdate com-
plex. This complex is then reduced to an intensely blue-colored complex by as-
corbic acid. The color is proportional to the orthophosphate concentration.
In these tests, only orthophosphate forms a blue color. Polyphosphates and
some organic phosphorus compounds may be converted to the orthophosphate form
by sulfuric acid hydrolysis. Organic phosphorus compounds are converted to
the orthophosphate form by persulfate digestion.
Total phosphorus (P, all phosphorus present in the sample, regardless of
form) is measured by the persulfate digestion procedure. The total orthophos-
phate content [(P04)-3] is measured by the direct colorimetric procedure and
is designated P-ortho~/
25
-------
Total Sample no fi I tration
Sample
H2S04 Pe rsu I fate
Direct Hydrolysis & Digestion
Colorimetry Colorimetry , Colorimetry
Orthophosphate Hydrolyzabll & Phosphorus
(Dissolved and 0 rthophosphate-:( ( Total)
I nsol uble)
I Fi Iter (through 0.45}.L membrane filter)
I
Residue Fi I trate I
,
H2S04 Persu I fate
Direct Hydrolysis & Digestion &
, Colori metry , Colori metry , Colorimetry
Dissolved Dissolved Dissolved
Orthophosphate Hydrolyzable & Phosphorus
Orthophosphate
(
)
* These forms are not synonymous.
Source:
Reference 15.
Figure 4-1.
Analytical scheme for differentiation of phosphorus forms.
26
-------
Total hydrolyzable phosphorus (P-hydro) is measured by sulfuric acid hy-
drolysis and a colorimetry procedure with a correction provided by subtrac-
tion of predetermined orthophosphate values. The hydrolyzable phosphorus in- /
cludes polyphosphorus [(P207)-4, (P30l0)-5, etc.] plus some organic phosphorus.~
The content of total organic phosphorus (p-org) in samples is determined
by the persulfate digestion procedure after correction by subtraction of hy-
drolyzable phosphorus and orthophosphate values.
Total dissolved phosphorus (P-O) is defined as all of the phosphorus prei-
ent in the filtrate of a sample passed through a filter of 0.45 ~pore size.12
This form of phosphorus is measured by the persulfate digestion procedure. Ois-
solved orthophosphate phosphorus (P-O, ortho) is measured by the direct color-
imetry procedure. Oissolved hydrolyzable phosphorus (P-O, hydro) is determined
by the sulfuric acid hydrolysis procedure allowing for subtraction of predeter-
mined dissolved orthophosphate values. The content of dissolved organic phos-
phorus (P-O, org) is measured by the persulfate digestion procedure with the
subtraction of predetermined values of dissolved hydrolyzable phosphorus and
orthophosphate.
When sufficient amounts of insoluble fo~s of phosphorus are present in
samples to warrant consideration, the forms which may be calculated are:~/
Insoluble phosphorus
(P-I) = (p)-(p-O)
Insoluble hydrolyzable
phosphorus
(P-I, hydro) - (p, hydro)-(p-O, hydro)
Insoluble organic
phosphorus
(P-I, org) = (P, org)-(P-O, org)
CHEMICAL REACTIONS AND TRANSPORT OF PHOSPHORUS
Phosphorus in Natural Waters
The forms of phosphorus in natural waters are indicated in Table 4-2 and
discussed in the following paragraphs.
Inorganic Phosphates--
These compounds may include the ions of or tho phosphoric acids ;H2P04-'
HP04-2, P04-3) and polyphosphoric acids (P207)-4, (P30l0)-5, etc~ The or-
thophosphate ions generally comprise 40 to 50% of the total p'hosphorus present
in natural stream water regardless of adjacent land usage.l2t
Inorganic phosphates may be present in either a dissolved form or as part
of suspended matter (e.g., particles of apatite [calO(P04)6F2] or inorganic
27
-------
TABLE 4-2.
FORMS OF PHOSPHORUS PRESENT IN SURFACE AND WASTEWATERS
Dissolved phosphorus
Suspended phosphorus
Orthophosphate
[(P04)-3]
As organic colloids
and/or combined
with an adsorp-
tive colloid
As mineral particles
(e.g., apatite) and/or
adsorbed on inorganic
complexes such as
Fe(OH)3
Organisms
Adsorbed on detritus
and/or present in
organic compounds
(
Total phosphorus in filtrate
)
(
Total phosphorus content of unfiltered water
)
N
Q)
Source:
Reference 4.
-------
complexes). Dissolved inorganic orthophosphates are the forms of phosphorus
most easily used as a nutrient by algae and other photosynthesizing plants.l£/
Because inorganic orthophosphate is recognized as the principal form of
phosphorus utilized in plant nutrition, much of the literature addressing the
role of phosphorus in eutrophication concentrates on the relative abundance
of orthophosphate. However, current research indicates that inorganic phos-
phorus compounds often comprise less than 10% of the total phosphorus present
in aquatic ecosystems~/ Soluble inorganic phosphorus is only a transient
component of lake or river water. Living cells quickly utilize such compounds
because of their critical need for phosphorus~/
Organic Phosphorus Compounds--
Naturally produced organic phosphorus is derived from intracellular or-
ganic matter as well as extracellular orthophosphate.
They include nucleoproteins, phospholipids, teichoic acids (a major com-
ponent of bacterial cell walls and membranes), aminophosphoric acids, and sugar
phosphates or their decomposition products.1&
Organic phosphorus in natural waters is present in five major storage
sites: living and dead suspended particulate matter, filterable organic com-
pounds, rooTed and encrusted bottom plants, free-living animals, and bottom
sediments.~ The significance of the large quantity of phosphorus represented
by these five reservoirs is increased by rapid recycling from one site to
another or from one organism to another. The movement of phosphorus from dying
cells into the surrounding water and the subsequent uptake by nearby living
cells has been studied with the use of radiophosphorus (p32). Bacteria have
demonstrated the ability to uptake, utilize, and excrete phosphorus within
minutes.l2/
Photosynthesis is a process of photophosphorylation in which inorganic
phosphate and ADP (adenosine diphosphate) combine chemically in sunlit cells
to yield ATP (adenosine triphosphate). This synthesis is the primary source
of energy in autotrophic cells. The energy is released when needed by revers-
ing the reaction (ATP~ADP + inorganic P + energy). Similar biochemical pro-
cesses utilizing organic phosphates are responsible for energy storage and use
in heterotrophic cells, as well.
Aside from the importance of phosphorus in energy transformation within
cells, phosphorus is also essential in the production of many cellular con-
stituents, including phosphoproteins and nucleic acids~/
29
-------
Phosphorus in Wastewaters
The principal forms of phosphorus in municipal wastewater are: orthophos-
phates (P04)-3, polyphosphates or condensed phosphates [(P207)-4, (P30l0)-5,
etc.], and or~anic phosphorus compounds (fecal material, garbage disposal
waste, etc.). 0,21/
Generally, soluble orthophosphates are available as nutrients to all forms
of life, while phosphorus in other oxidation states is not immediately avail-
able.20,2l/ Condensed phosphates, such as pyrophosphates and tripolyphosphates,
will hydrolyze in natural waters or during wastewater treatment to the usable
orthophosphate form. No data specifying hydrolysis time were found in the tech-
nical literature.
Phosphorus in Sediments and Phosphorus Cycling Within Lakes
Phosphorus in surface water sediments can result from decomposition of
organic matter, the physical buildup of phosphorus-containing plant debris
(e.g., dead algae and also terrestrial vegetation), chemical precipitation,
and ion exchange with iron, aluminum, and calcium. In acidic lake sediments,
inorganic phosphorus is largely combined with iron and aluminum, while in al-
kaline sediments, calcium phosphate predominates.
Phosphorus exchange between bottom sediment and the surrounding water is
critical to the maintenance of a lake ecosystem. In the absence of human ac-
tivity, phosphorus is typically the limiting nutrient in a lake.~/ As a re-
sult, all phosphorus entering a lake is of great value~ and life forms present
in lakes have developed mechanisms to make the best use of the available phos-
phate. Natural recycling processes reuse phosphorus in a series of algae crops.
The following example will serve to illustrate the foregoing discussion.
When dead leaves are windborne or waterborne into a lake, they accumulate
on the lake bottom. In aerobic shallows they become a feedstock for invertebrates
and bacteria. Likewise, if anaerobic conditions exist (as might be the case at
the bottom of the hypolimnion of a eutrophic lake), the leaves become the fuel
for the metabolic activity of anaerobic bacteria. In either case, the phosphorus
present in the original leaf tissue is incorporated into the microorganisms,
which populate the lake bottom. These cells, in turn, are a food source for
detritivores.*
*
Detritivores are organisms that inhabit the debris at the surface of the
bottom sediment under aerobic conditions.
30
-------
Twice a year in second order dimictic* lakes located in temperate cli-
mates (with the exception of meromictic lakes**), the nutrients that are dis-
solved or present as suspended solids in hypolimnetic water are distributed
throughout the lake by overturns. These events are physical phenomena thaJ re-
sult from the seasonal temperature (density) changes of the lake water.ll
During the summer months, the water beneath a lake's metalimnion, the
boundary zone between warmer surface waters and the cooler waters of the hy-
polimnion, tends to establish a temperature close to that of the local ground-
water (10 to 16°C or 50 to 60°F) with a slight heating effect possible from
bacterial metabolism of sediment. Thermal stratification prevents oxygen of
atmospheric origin from entering the hypolimnion. Hypolimnetic nutrients are,
similarly, unable to enter the epilimnion (the warmer, surface water). During
the fall, decreasing atmospheric temperatures cool the lake water above the
metalimnion to a temperature equal to or below that of the hypolimnion. The
density difference between shallow and deep water is reversed. Subsequently,
the metalimnion temporarily ceases to exist, and the lake water literally
"overturns." The nutrient-rich hypolimnetic water comes to the surface to
fertilize algal growth, and the highly oxygenated, cold surface water sinks
into the depths to provide a fresh oxygen supply for benthic organisms. In
lakes that have a winter ice cover, a similar overturn event occurs during the
spring thaw)/
As a result of these overturns, the phosphorus present in the original
leaf tissue is now available to algae growing in the epilimnion.*** As the
vegetation thrives, dead plant debris slowly settles to the lake bottom where
the phosphorus is again utilized by saprophytic**** organisms and becomes part
of the semiliquid ooze which lines the lake basin. Overturns recycle the phos-
phorus until it precipitates into a stable inorganic complex or some other
form too heavy for overturn transport, or until it is washed out of the lake
basin by an outlet stream.
In the warmest regions of the United States (Florida, southern Texas,
and southern California), stratified lakes may not establish the uniform tem-
peratures from surface to bottom necessary for an overturn, even once a year.
Nutrient transport from hypolimnetic water and sediment is, thereby, severely
restricted.
*
A second order dimictic lake is a lake of moderate depth (~ 10 to 30 m
maximum depth) in which two overturns (spring and fall) occur annually.
Meromictic lakes are chemically stratified due to the intrusion of saline
waters or salts liberated from sediments. This stratification is perma-
nent, and ~nly the epilimnion circulates.~/
The epilimnion is the upper layer in a thermally stratified lake.
Saprophytic organisms are those bacteria and fungi that utilize decaying
organic matter as a substrate for growth.
i(*
~'d(*
i(*~,(*
31
-------
The preceding description of lake overturn is applicable to many of the
larger lakes and reservoirs in the continental United States; however, numer-
ous smaller third order lakes and ponds are too shallow to stratify « 10 m
maximum depth).1/ The most shallow of these lakes (~ 5 m maximum dept~/) are
very vulnerable to eutrophication, even in the absence of man-made ecosystem
disruptions. (European limnologists first used the term "eutrophic," to de-
scribe lakes of this type.]/)
Sunlight is available to a much larger percentage of the water in a shal-
low lake than would be the case in a deep stratified lake. The lack of depth
encourages the growth of rooted plants as well as free-floating ones. Dead al-
gae support a large population of microorganisms at the lake bottom. Water
circulation caused by wind and simple diffusion continually reintroduces nu-
trients to the (trophogenic)* zone near the water's surface. It is not uncom-
mon for the rate of biomass decomposition in such a lake to consume so much
oxygen that fish kills occur.ll/
Regardless of the area covered or the depth of a lake, when the level of
total phosphorus present in the lakewater exceeds the ~ 25 ~g/liter suggested
for eutrophic conditions, there is an increase in plant production. Observa-
tions of the contrasting algae/macrophyte populations occurring in eutrophic
and oligotrophic** lakes demonstrate this heightened production, as do the
results of laboratory bioassay procedures designed to quantify the ability
of lakewater to produce algal biomass.24/
Another result of high phosphorus levels in lake water is an increase in
the amount of phosphorus contained in or adsorbed on algal cells. Algae are
able to stockpil~ phosphorus when it is abundant. This ability is known as
luxury uptake.251 Two consequences of the formation of this living reservoir
of phosphorus in eutrophic waters are: (a) significant quantities of phos-
phorus (much of which is likely to be orthophosphate25/) are made available
to growing algae when mature plants die and decay, and (b) significant quan-
tities of phosphorus are deposited in the sediments as a constituent of plant
debris and, thus, are available for recycling by way of biological, physical,
and physical-chemical processes.
When the activities of human society (i.e., municipal waste disposal,
agriculture, industrial waste disposal) enrich the phosphorus content of lake
water, the natural mechanisms designed to conserve and recycle phosphorus con-
tinue to function. Over a period of a few years, the sediment layer may accumu-
late a high amount of phosphate and biomass that could require thousands of
"k
Trophogenic zone is the zone of net increase in biomass.
Oligotrophic lakes are nutrient-poor and support only meager
lations.
algae popu-
i'ci',
32
-------
years for deposition under natural runoff conditions. The lake basin fills with
sediment at an accelerated rate. Anoxic conditions may develop beneath the
metalimnion because of oxygen depletion due to decaying organic matter. As a
result, the diversity of benthic species (but not necessarily biomass) is
drastically reduced.
The biological processes involved in the sedimentary phosphorus cycle
command much attention in a discussion of eutrophic growth potential; however,
purely chemical changes also occur.l£/ Phosphorus can be released from lake
sediment by desorption mechanisms. The reduction of ferric to ferrous ions is
thought to be an important triggering mechanism in the desorption of phos-
phorus from iron-containing sediment. When hypolimnetic dissolved oxygen is
depleted by oxidation of organic matter, there is a decline in the pH and the
oxidation-reduction potential at the sediment surface. A mechanism which lim-
its molecular and/or ionic diffusion between sediment and water under aerobic
conditions is broken down. This mechanism is thought to involve a ferric ox-
ide barrier which is eliminated by the formation of soluble ferrous phosphate
under the circumstances just mentioned. Stibsequently, ortholhosphate is able
to diffuse from the bottom mud into the hypolimnetic water.-1/
SOURCES OF PHOSPHORUS
Definitions and brief
of phosphorus discharge to
paragraphs.
discussions of point sources and nonpoint sources
the environment are presented in the following
Point Sources
These sources deliver phosphorus to surface waterS or the atmosphere in
discrete, measurable streams~! Examples include the wastewater discharge
pipes at municipal sewage treatment plants or chemical processing plants, and
the vent pipes and chimneys on factory buildings used to discharge waste gases
to the atmosphere.
Nonpoint Sources
A nonpoint source is a pollution-generating activity. which results in
diffuse discharges of phosphorus-containing materials~7 The nature of non-
point sources is very diverse, as the following examples will illustrate. They
usually originate from either the lithosphere or the biosphere, and the actual
emission may enter surface waters, the atmosphere, or be deposited on the land.
Emission may be made from the atmosphere, from surface waters, or from land.
Examples of water-based nonpoint emissions include sewage and garbage dis-
posal from commercial ships or recreational boats on inland lakes or waterways,
as well as ocean dumping of sewage, garbage, and other wastes.
33
-------
Examples of land-based nonpoint emissions are:
~'(
Runoff from major land use areas such as croplands, pastures, range-
lands, forests, livestock feedlots, urban districts, and rural road-
ways.
*
Leaching from improperly managed or constructed landfills and trash
dump s .
..,t(
Septic tank systems.
i'(
Emissions caused by applications of phosphorus-based fertilizers and
biocides to lawns, gardens, farms, and managed forest areas.
it:
Forest fires.
ok
Burning of agricultural wastes.
ok
Deciduous tree leaves.
Rainfall and other forms of precipitation (e.g., snow or dry fallout
settled dust) contaminated with phosphorus are examples of pollution
charged from the atmosphere to either surface waters or land areas.
such as
dis-
Phosphorus Load
The phosphorus load from any given source entering surface waters is the
weight of total phosphorus discharged to the receiving waters per unit of time
. (e.g., ~tSS of total phosphorus expressed as kilograms phosphorus per unit of
time).1- The load may result from various sources, such as watershed runoff
or point effluent discharges from municipal sewage treatment plants or indus-
tries. Part of the loading may be due to air pollutants (e.g., particulates
containing phosphorus with adsorbed phosphorus which settle into surface waters).
The background phosphorus load is that portion of the total phosphorus load
which is attributable to natural effects such as runoff from land apparently
undisturbed by man's activities (e.g., runoff from native forestland, leachinr
of exposed phosphate rocks which are part of an unmined ore deposit, etc.).~
Phosphorus Burden
Phosphorus burden is the in-stream total phosphorus concentration deter-
mined by water quality measurements. Some of the phosphorus load discharged
to streams can be converted by physical or chemical changes to forms which de-
posit on the stream bottom and thereby decrease the phosphorus concentration
in the water. Background burden is the phosphorus concentration determined
under circumstances which approximate a condition undisturbed by man.~/
34
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Standard Industrial Classification (SIC) Codes
The SIC categorizes industries over the entire field of economic activ-
ities. It is revised per/iodically to reflect the changing industrial compo-
sition of the economy~
The SIC was developed for use in classifying establishments by type of
activity; to facilitate collection, tabulation, presentation, and analysis of
data relating to establishments; and to promote uniformity and comparability
in the presentation of statistical data collected by agencies of the U.S. gov-
ernment~ state agencies, trade associations, and private research organiza-
tions .1.../
A list of phosphorus-related SIC codes is shown in Table 4-3. All of
these industries either have phosphorus waste streams or discharge phosphorus
inadvertently by process material leaks and spills during manufacturing opera-
tions. The industries in these SIC codes are sources of phosphorus discharge
to the environment.
Other industries which also have significant phosphorus discharges to the
environment or to municipal treatment facilities include the many segments of
the food and fiber industries. When fluids and cells from once-living tissues
enter wastewaters, organic phosphorus compounds will be present. Phosphorus
levels in production wastewaters are increased further, whenever sanitation
or production efficiency requires the extensive use of detergents.
SOILS AND PHOSPHORUS MOVEMENT
Soils contain a mixture of inorganic particles with various compositions
and sizes (particles less than 2 ~ have colloidal pro~erties) and enmeshed or-
ganic matter with a wide range of molecular weights.1-/ A portion of the inter-
particle voids in undisturbed soil is occupied by water, living plant roots,
and macro- and microorganisms, and the remainder of the volume is the gaseous
soil atmosphere.
The inorganic colloidal (clay mineral) portion of the soil is comprised
mainly of aluminum silicate polymers~/ Silica is leached from the clay min-
erals, leaving behind Al(OH)2+ groups that are active in specific adsorption
of polybasic anions, including all phosphate compounds.l&/ When phosphate fer-
tilizers and polyphosphates used in industry and agriculture are introduced
into a soil, these compounds hydrolyze rapidly to orthoph/osphate by the ac-
tivity of soil microorganisms and chemical hydrolysis~ No information was
found in the literature concerning the time frame in which this hydrolysis
occurs.
35
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TABLE 4-3.
PRODUCTS UTILIZING PHOSPHATE ROCK-DERIVED PHOSPHORUS
ARRANGED BY SIC COD~/
Industry No.
Description
Chemical and Fertilizer Mineral Mining
1475
1479
Phosphate rock
Other fertilizers not elsewhere classified (i.e., guano)
Grain Mill Products
2045
2047, 2048
Blended and prepared flour (phosphated flour)
Food products for pets and livestock
Beverages
2086
Bottled and canned soft drinks and carbonated waters
(H3P04 use)
Industrial Inorganic Chemicals
2819
Industrial inorganic
phosphates (except
phorus, phosphorus
chemicals not elsewhere classified:
defluorinated and ammoniated phos-
oxychloride, etc.)
Drug s
2834
Pharmaceutical preparations
Soaps. Detergents. and Cleaning Preparations
2841, 2842
Soaps, other detergents, and specialty cleaning products
Industrial Organic Chemicals
2865
Cyclic crudes, cyclic intermediates, dyes, and organic
pigment lakes and toners
2869
Industrial organic chemicals:
phoric acid esters
triphenyl phosphate, phos-
Agricultural Chemicals
2874
Phosphatic fertilizers, phosphoric acid
(continued)
36
-------
TABLE 4-3.
(continued)
Industry No.
Description
2875
Fertilizers, mixing only
2879
Pesticides and agricultural chemicals not otherwise
classified
~I
Adapted from Reference 27.
bl
This table includes the primary products in which mined P enters the u.s.
market.
37
-------
Soil phosphorus has been classified into the following general categor-
ies: calcium phosphate, aluminum- and iron-phosphate, and organic phosphorus
compounds. The quantity of phosphorus in the organic portion of the soil is
reported to range from 15 to 80% of the total phosphorus.l£l Residues of
plants and living and dead macro- and microorganisms comprise the organic
portion of the total phosphorus content.
One of the most si~nificant characteristics of phosphorus in the soil is
its general immobility. 9,30,311 Essentially all phosphorus applied as fertil-
zzer is converted to water insoluble forms within a few hours. When the soil
is undisturbed, the phosphorus moves little over a period of years. However,
in cultivated soils, the phosphorus is redistributed through the plow depth
(approximately 15 cm). Except for well-drained soil areas on which applica-
tions of large amounts of both water and fertilizer are used, essentially none
of the phosphorus moves downward by water percolation to the groundwater ta-
ble.lQl
One reason for the immobility of phosphorus is the element's strong ad-
sorption to finely divided soil particles (e.g., clay minerals, iron and
aluminum oxides, and some organic materials). The maximum concentration of
phosphorus in soil solution extracts is reported to be about 0.1 ppm, even
for soils which have been heavily fertilized.291 About 40 to 507 of this to-
tal phosphorus in soil solution is present as orthophosphate~
In addition, phosphorus applied to soil can become immobilized because
of its reaction with cations. In acidic soils, the formation of insoluble
iron and aluminum phosphate reduces the availability of phosphorus as a fer-
tilizer.~ In alkaline soils, orthophosphate may react with calcium carbo-
nate to produce relatively insoluble hydroxyapatite according to the reaction:
6HP042- + 10CaC03 + 4H20-7CalO(P04)6(OH)2 + 10HC03- + 20H-
Phosphorus adsorbed on soils can migrate overland with soil solids to wa-
ter systems.291 Erosion of topsoil, carrying phosphates directly to rivers and
lakes, is more important in water fertilization than the relatively small
amounts of phosphorus which may be transported via percolation to subsoil wa-
ters.281 Overland transport (erosion) is the principal nonpoint mechanism of
phosphorus loss from land sources. The sources of phosphorus in the soil that
are subject to transport by erosion include: (a) naturally occurring phos-
phorusi (b) applied commercial fertilizers and manures; and (c) plant resi-
dues.l-I
The phosphorus originally bound in the soil generally remains immobilized
and is not subject to a significant amount of transport by solubilization.28,29,301
Under certain circumstances, however, such as highly acidic soil conditions
(e.g., caused by bacterial activity, high sulfur content soils, or excessive
38
-------
fertilizer applications), solubilization and transport of phosphorus can occur.
In general, phospnorus remains bound in the soil and is transported principally
by soil erosion (i.e., sediment in runoff)~/ .
Much of the phosphorus applied to land is retained in the soil as unavail-
able mineral phosphorus or transported through erosion to receiving waters.
Soil management practices to reduce erosion (e.g., reduction of fall plow-
ing, minimum overall tillage, terracing, strip cropping, etc.) could decrease
phosphorus losses from runoff and reduce the subsequent impact on water qua1-
ity.29,30,31/
Leaching from septic tank tile fields can contribute nutrients (e.g.,
phosphorus and nitrogen) to groundwaters with the most significant transport
resulting from tile fields constructed in coarse sand, gravel, or soil types
which are low in clay and silt content.~/ Sands and gravels do not have a
significant adsorptive capacity for phosphorus and, therefore, these materials
do not bind phosphorus in the soil. The key to retaining phosphorus within an
aquifer system is the presence of clay minerals, organic matter, iron oxide,
aluminum oxide, and limestone. Because of the high adsorptive capacity of most
soils for phosphorus, only small concentrations of phosphorus are usually found
in waters entering streams from groundwater aquifers.29/
PHOSPHORUS REMOVAL
Septic Tanks
Septic tanks are the most numerous type of wastewater treatment and dis-
posal system serving an estimated 50 million Americans in homes and other
small dwelling units.ll/ The popularity of such devices is of course re-
lated to the needs of remote sewage treatment but also because of the sim-
plicity and accepted efficiency of these units. The septic tank is an ac-
ceptable method of treatment for individual disposal systems (e.g., residences,
schools, camps, institutions, etc.) where municipal waste treatment is not
avai1ab1e.187
A septic tank system consists of a detention tank and an adjoining
lateral field. The wastewater enters the detention tank where settleable
solids are accumulated with concomitant biological decomposition. Grease and
other floatables can also be captured so that only the nonsettleable liquid
portion of the wastewater leaves the tank and enters the lateral field. Pe-
riodically the accumulated solids should be removed by pumping for ultimate
disposal in larger treatment plants.
The lateral field consists of trenches, piping, and gravel whereby the
septic tank effluent is distributed into the soil for ultimate disposal. This
fraction of the wastewater ultimately ends up in the groundwater by seepage
or in the atmosphere via evaporation. However, the constituents themselves
39
-------
are subject to numerous interactions with the soil and can accumulate in this
medium.
The soil phase of the septic tank system is the most crucial because a
failure can cause the incoming wastewater to backup and/or to seep to the sur-
face of the ground. This occurs because of inadequate soil conditions, weather
extremes, interfering vegetation and groundwater, or wastewater overloads.
The soil microorganisms are the main characters in the treatment processes
occurring within the lateral field. They convert biodegradable organic matter
to new cells. Solids carried over from the septic tank are accumulated and de-
composed on the underdrain surface. Numerous biological transformations can
occur depending upon the particular environment that exists within the soil
system, e.g., the aerobic metabolism of the wastewater will create a slime
layer on the trench wall which will reduce the infiltration of the wastewater
into the surrounding soil. This reduction will in turn cause the liquid to
be retained longer in the soil so that other desirable chemical reactions can
occur which will reduce the movement of the components into the groundwater.
An overgrowth of this layer, caused bv wastewater overloads or inadequate
resting time, would plug the soil so that flooding and seepage occurs with-
out proper treatment of the wastewater contaminants.
In a normal septic tank system, a dynamic phosphorus balance is estab-
lished in the soil which comprises the effluent drain field. Some of the
phosphorus originally adsorbed on soil particles is converted by soil micro-
organisms to highly stable cellular protein forms (i.e., humus). This micro-
bial action releases phosphorus from adsorption sites and helps to maintain
an adequate adsorption capacity for phosphorus in the septic tank drain field.
plant roots also take up some of this phosphorus if the field is not too deep.
Although most septic tank systems are in continuous use, there are those
which serve on a discontinuous basis, especially those at recreational areas
such as camps, retreats, etc. Concern is expressed for the performance of such
installations because of the die-off (due to starvation) of the microorganisms
responsible for the stabilization of the contaminants in the wastewater. This
is not a valid concern because a significant portion of domestic sewage is
the microorganisms. Besides these mirobes, the soil organisms will remain
dormant until the right environmental conditions reappear. There are adequate
seed microorganisms to initiate the biological processes necessary for the
treatment of such intermittent discharges. In fact, as with all soil systems,
there needs to be a resting period so that the microbes can recover from sys-
tem overloads.
There are some conceivable natural and anthropogenic causes of phosphorus
desorption and migration in soils. In some isolated instances, septic tanks
40
-------
may be situated in soils having a relatively high sulfur content (e.g., the
presence of iron pyrites in areas near coal mines). Soils containing suf-
ficient amounts of pyrite minerals can generate acidic soil solutions which
are capable of solubilizing and transporting phosphorus. Also, it is probable
that acidic solutions generated by excessive applications of nitrogen ferti-
lizer (e.g., ammonium nitrate) Or phosphate fertilizer near septic tanks
could cause desorption and migration of phosphorus in the soil.
In general, the components contained in septic tank effluents are re-
tained in the soil system while the treated liquid passes on to the environ-
ment. However, it should be realized that the capacity of any system can be
exceeded and soils are no exception. As mentioned above, excesses and poor
designs can result in incomplete treatment and pollution of the environment.
Phosphorus Removal in Septic Tanks
Numerous studies have been made to determine the behavior of soil sys-
tems as a wastewater treatment process. However, the particular study of
phosphorus removal in septic tank systems is quite limited. It is recognized
that phosphorus removal in the detention tank itself is comparable to that
achieved in primary treatment at larger facilities, i.e., 10 to 20%. However,
the removal accomplished in the lateral soil system is not well known.
Sawhney and Starr presented one of the most recent reviews of phosphorus
removal in a septic tank drainfield.32/ Spatial measurements of phosphorus
were made around a trench over a 2-year period. Results indicated that phos-
phorus removal was quite effective (90 to 99+%) and occurred in the first
30 em of the soil. Furthermore, it was speculated that soils with a deep water
table should have adequate capacity to remove phosphorus for a number of
years. However, the authors cautioned that shallow soils with high or perched
tables would likely permit undesirably large additions of phosphorus to the
groundwater. A similar conclusion was reached bj Viraraghaven and Warnock who
measured phosphorus removals of only 25 to 5~!o.-l1
Sewage Treatment Processes
The effect of increasing pollution load on the environment has resulted
in the development of more efficient means to treat man's wastes. For domestic
sewage, the evolution of process development has moved from primary to tertiary
treatment as illustrated in Figure 4-2. The particular level of treatment
used by a community will depend upon many factors but most municipalities are
providing or will provide secondary treatment according to P.L. 92-500. Some
cities are or will provide advanced or tertiary treatment because of their
unique wastewater characteristics and limited water resources for effluent
disposal. .
41
-------
Influent
Source:
Pri mary
T reatme nt -
Screening or
Sedimentation
r------------------,
I I
I Secondary Treatment I
I I
I I
I Biological I
I Treatment Settling I
I I
I I
I I
I I
L______------- ----...
Sludge
Reference 34.
Figure 4-2.
Simplified flow diagram of municipal sewage treatment.
42
Effluent
Tertiary
Treatment
(Chemical)
Sludge
-------
Primary Treatment--
This treatment can be considered as solids treatment. Early efforts to
control municipal pollution involved the separation of solids from domestic
sewage with their subsequent treatment. This usually involved screening,
sedimentation, and anaerobic digestion.34/ The inorganic solids were even-
tually disposed of on the land and the organic solids were stabilized or
rendered less obnoxious in a biological process of anaerobic digestion. Resi-
due from this process was also returned to the land.
Of course other treatment methods have evolved to accomplish primary
treatment but they all deal with reducing the environmental effects of sewage
solids.
Secondary Treatment--
Solids treatment alone was not adequate to keep pace with the changing
environmental situation, so secondary treatment was added to accomplish a more
complete degree of pollution control. Basically, secondary treatment involves
the removal of residual biodegradable organics from a primary process. These
compounds are colloidal and soluble in nature and thus require another means
for their removal (other than mechanical or physical). The most cammon method
of removal is by biological treatment using the various types of trickling
filter or activated sludge processes~/
The trickling filter process involves the use of a support media (rock,
wood, plastic, etc.) for microorganisms which are responsible for the removal
of the biodegradable contaminants left in the primary treatment effluent. The
process is considered facultative, i.e., it operates with and without oxygen.
The wastewater is trickled over the media coated with microbes and after treat-
ment is sent to a sedimentation tank where accumulated biosolids are removed.
The activated sludge process is an aerobic or oxygen dependent treatment
scheme where primary effluent contaminants are converted to biosolids in a
liquid environment called an aeration tank. It does not use support media,
intermittent or trickling application, or partially aerated liquid as does
the trickling filter. Usually a higher degree of treatment is accomplished in
the activated sludge process. This is due to the improved process control and
aerobic environment.
The sedimentation tank following the aeration tank is used to separate
the biosolids from the treated wastewater. These solids can be reused in the
aeration tank to facilitate the treatment efficiency. It is important that
this part of the activated sludge process perform satisfactorily or biosolids
can be lost to the effluent with reduced overall treatment efficiency.
43
-------
Tertiary Treatment--
Any treatment over and above secondary is referred to as tertiary and it
can take many forms depending upon the environmental situation. The most common
treatment concerns include nutrient (phosphorus and nitrogen), refractory
organic, pathogen, residue solids, or trace metal removals. Treatment methods
vary according to the particular components but include such processes as
chemical precipitation, stripping, breakpoint chlorination, carbon adsorption,
ion exchange, etc~/ Thus far, it can be concluded that such advanced treat-
ment schemes are not commonplace but are used where special environmental con-
cerns exist, e.g., phosphorus removal where eutrophication is a problem.
A relative idea of approximately how much third-degree treatment (primary,
secondary, and tertiary for phosphorus removal only) costs when compared to
second-degree treatment (primary plus secondary) was obtained by a review of
technical literature~/ The capital investment and operating costs for the
three-degree system are estimated to be about 34% and 67% higher, respectively.
Phosphorus Removal Processes--
Phosphorus removal is usually considered necessary when it is identified
as the causative agent for eutrophication. Various treatment methods exist for
its removal but the most common (hence economical) is by chemical addition.
This is the subject of a revised manual on phosphorus removal by EPA.36/
The basic mechanisms of phosphorus removal by chemical addition involves
precipitation and/or colloidal destabilization. When the solubility products
of phosphorus salts are exceeded, then chemical precipitation will occur.
Hence, chemicals are selected which will form these salts with phosphorus so
that the phosphorus in the wastewater will become insoluble and can be re-
moved by sedimentation and/or filtration. Quite often the phosphorus has been
complexed into colloidal forms by combination with other contaminants in the
wastewater. Such particulate forms of phosphorus can be effectively removed
by colloidal destabilization using chemicals.
Colloidal destabilization consists of coagulation which involves the
interaction of the treatment chemical with the colloids creating an unstable
suspension and flocculation which involves the interaction of the chemically
destabilized colloids to form a settleable suspension. Mineral chemicals like
alum, aluminate, and iron salts are used as coagulants to accomplish phos-
phorus removal. Lime is also used as a coagulant and a chemical precipitant.
The 1976 EPA manual on phosphorus removal reviews the treatment alterna-
tives for phosphorus removal from domestic wastewaterS using the above men-
tioned chemicals. Six basic methods are described with supportive data from
actual field and pilot studies. These methods include chemical addition at
44
-------
various points along the conventional treatment train where a phosphorus sus-
penion can be removed by sedimentation and/or filtration. This involves re-
moval in the primary, secondary, or tertiary sedimentation basins.36/
Typical removal efficiencies are summarized later in Table 6-14 but it
should be recognized that such removals are site specific, i.e., one must in-
vestigate and determine what 1evea1s of removals can be accomplished with a
particular wastewater-chemical combination. However, in general, deliberate
attempts to remove phosphorus by chemical treatment is significantly better
than the unintentional phosphorus removal accomplished in conventional treat-
ment for solids and biodegradable organic removals.
Phosphorus Removal from Municipal Wastewater by Chemical Precipitation Methods--
Demonstration tests conducted in Canada have shown that is is feasible
to chemically treat wastewater for phosphorus removal during primary or
secondary treatment operations without using the relatively expensive tertiary
treatment methods described earlier.
Full-scale tests in municipal wastewater treatment plants in Ontario,
Canada, during the period of 1971 to 1975, have demonstrated that removal of
phosphorus from wastewater effluents by chemical precipitation is a feasible
and cost effective method for reducing phosphorus discharge to water bodies.lL/
Precipitation of phosphorus compounds by the use of lime, iron, or aluminum
compounds have been investigated in both primary and secondary treatment
plants. In contrast to tertiary treatment by coagulation to remove several
pollutants, the primary purpose of these precipitation methods is to remove
phosphorus.
Basic statistics for the Canadian study program on chemical phosphorus
removal are shown in Table 4-4. When iron (as ferric chloride) or alum was
used as the chemical precipitant, the average dose requirements and the che~
ica1 costs were considerably higher for raw wastewater treatment than for ad-
dition to mixed liquor. The lowest average chemical cost for addition to raw
wastewater applies for the process which uses lime as a treatment chemicala37/
Treatment processes using lime as a phosphorus precipitant--The calcium
ion reacts with phosphate ion in the presence of hydroxyl ion to form hydroxy-
apatite.l£/ The approximate equation for the reaction can be written as fol-
lows, assuming that the phosphate is present as HPO~-:
2- 2+ -
3 HP04 + 5 Ca + 4 OH
) Ca5(OH)(P04)3 + 3 H20
The process (high lime) described below for treatment of raw wastewater,
with lime added in the primary treatment unit, can consistently produce phos-
phorus levels below 1 mg/liter when flocculant aids and filtrations are used.36/
45
-------
TABLE 4-4.
BASIC STATISTICS FROM THE CANADA-ONTARIO FULL- SCALE TREATABILITY
STUDY PROGRAM--TO ACHIEVE AN EFFLUENT PHOSPHORUS REQUIREMENT
OF 1 MG/LITER
Addition to raw wastewater
primary treatment plant
Avg cost~/
Total No. No. of Avg dose ($/mi llion
Chemical of plants plants (mg/t) gallons)
Iron 22 7 l6.~/ 26.9 15 9.2 15.0
Alum 20 5 10.3E/ 33.5 15 7.2 21.7
Lime 3 3 11#/ 25.5
Addition to mixed liquor
secondary treatment plant
Avg cost~/
( $/million
ga llons )
Avg dose
(mg/t)
No. of
plants
~
0\
Source:
Reference 37.
~/
Chemical cost only (December 1974, from consultants).
'E/
Dosages as milligrams per liter Fe/A1.
:=./
Dosages as milligrams per liter Ca.
-------
High lime treatment of domestic wastewaters is just one of the numerous
treatment alternatives for phosphorus removal. Excess lime addition in the
primary portion of a sewage treatment will significantly increase phosphorus
removal over conventional primary treatment; also, it will allow increased re-
movals over low-lime treatment in the primary. This is accomplished by adding
lime before the primary clarifier in order to raise the wastewater pH' to 11.0
or 11.5. The phosphorus will be precipitated as hydroxyapatite, leaving an ef-
fluent with less than 1 mg/liter/phosphorus. In addition, the water will be
softened, viruses deactivated, and heavy metals removed. Finally, the residual
phosphorus will be further reduced in the secondary portion of the treatment
plant by biological uptake.l£/
The addition of lime before the primary clarifier requires either chemi-
cal feeding equipment to produce a lime slurry or direct addition to the
wastewater. Either way, the lime must be uniformly mixed with the wastewater.
After lime dosage to the proper pH, the wastewater can be gently mixed in a
preaeration basin or flocculation tank to facilitate the production of a
chemical precipitate (flox) which is subsequently removed in the primary
clarifier; however, this is not always a necessity.
The volume of sludge produced in the primary clarifier is increased
markedly over conventional treatment. This increased volume is due to the
phosphorus, hardness, and heavy metal precipitates. Also, improved removal
of suspended solids will occur. This has the effect of reducing these load-
ings on the secondary biological treatment process and increasing them on the
anaerobic digestion or other solids processes. Research has shown that this
increased sludge loading is not detrimental to anaerobic digestion, but in
fact can improve the dewaterabi1ity of the sludge in the final treatment steps
of sand beds, centrifuges, or vacuum filters.
Another possibility of lime sludge treatment is the recovery of the
by recalcination. EPA suggests that plants treating more than 10 million
Ions per day (mgd) may find this method of chemical reuse economical.
lime
gal-
47
-------
REFERENCES TO SECTION 4
1.
u.S. Environmental Protection Agency. The Hazard of Phosphates in the
Environment. Draft Report, Office of Toxic Substances, Washington, D.C.,
September 1977. pp. 1-5, 24.
2.
Lee, G. F., W. Rast, and R. A. Jones. Eutrophication of Water Bodies:
Insights for an Age-Old Problem. Environmental Science and Technology.
12(8):900-908. 1978.
3.
Hutchinson, G. E. Eutrophication. American Scientist. 61(3):269-279.
1973.
4.
Vollenweider, R. A. Scientific Fundamentals of the Eutrophication of
Lakes and Flowing Waters, With Particular Reference to Nitrogen and
Phosphorus as Factors in Eutrophication. Organization for Economic
Cooperation and Development. Paris. 1968.
5.
Schindler, D. W. Carbon, Nitrogen, and Phosphorus, and the Eutrophication
of Freshwater Lakes. Journal of Phycology. 7(4):321-329. 1971.
6.
Schindler, D. W. Evolution of Phosphorus Limitation in Lakes. Science.
195(4275):260-262. 1977.
7.
Gakstatter, J. H., M. o. Allum, and J. M. Omernik. Lake Eutrophication:
Results from the National Eutrophication Survey. In: Proceedings of an
EPA-Sponsored Symposium, Water Quality Criteria Research of the U.S.
Environmental Protection Agency, EPA 600/3-76/079. 192 pp.
8.
Hynes, H. B. N. The Enrichment of Streams. Eutrophication: Causes,
Consequences, Correctives. National Science Foundation, washington,
1969. pp. 188-196.
D.C.
9.
Odum, E. P. Fundamentals of Ecology. 3rd ed. W. B. Saunders Company,
Philadelphia, Pennsylvania. 1971. pp. 312-323, 357.
10.
u.S. Environmental Protection Agency. PB-263 943. Office of Water plan-
ning and Standards, Quality Criteria for Water, 1976. pp. 354-360.
11.
Pomeroy, L. R., L. R. Shenton, R. D. H. Jones, and R. J. Reinhold.
Nutrient Flux in Estuaries ~ Nutrients and Eutrophication: The
Limiting Nutrient Controversy. G. E. Likens, ed. Proceedings of a
Symposium of the American Society of Limnology and Oceanography. 1972.
12.
Ketchum, B. H. Eutrophication of Estuaries.
Consequences, Correctives. National Academy
D.C. 1969. pp. 197-209.
Eutrophication: Causes,
of Sciences, Washington,
48
-------
13.
Lee, G. F., ed. Eutrophication. In: Kirk-Othmer Encyclopedia of Chemi-
cal Technology, 2nd ed., Supplement Volume, A. Standen, ed. 1971. pp. 315-
338.
14.
Porcella, D. B., et a1. Comprehensive Management of Phosphorus Water
pollution. Utah State University Report to the U.S. Environmental Pro-
tection Agency, Contract No.. 68-01-0728 (EPA 600/5-74/010), February
1974. pp. 22-26.
15.
U~S. Environmental Protection Agency. Methods for Chemical Analysis of
Water and Wastes. EPA 625/6-74/003, 1974. pp. 249-265.
16.
Halmann, M. Analytical Chemistry of Phosphorus Compounds. Volume 37 of
Chemical Analysis--A Series of Monogrgphs on Analytical Chemistry and
Its Applications, Wiley Interscience, New York City, New York, 1972.
pp. 727-747.
17.
Hutchinson, G. E. A Treatise on Limnology, Volume I, John Wiley and Sons,
New York City, New York, 1957. 731 pp.
18.
Griffith, E. J., A. Beaton, J. M. Spencer,
mental phosphorus Handbook. John Wiley and
1973. pp. 179-201, 509-538, 576-583.
and D. T. Mitchell. Environ-
Sons, New York City, New York,
19.
Rigler, F. H. A Tracer Study of the Phosphorus Cycle in Lake Waters.
Ecology, 37:559-560, 1956.
20.
Schindler, D. W. Eutrophication and Recovery in Experimental Lakes,
Implications for Lake Management. Science, 184:897-899, May 24, 1974.
21.
Grundy, R. D. Strategies for Control of Man-Made Eutrophication.
Environmental Science and Technology, 5:1184-1190, December 1971.
22.
McElroy, A. D., S. Y. Chiu, J. W. Nebgen, A. A1eti, and F. W. Bennett.
National Assessment of Water pollution from Nonpoint Sources. Draft of
Final Report from Midwest Research Institute to the U.S. Environmental
Protection Agency, Contract No. 68-01-2293, November 5, 1975. pp. 120-
122.
23.
Barica, J. Some Observations on Internal Recycling, Regeneration, Oscil-
lation of Dissolved Nitrogen and Phosphorus in Shallow Self-Contained
Lakes. Archiv fur Hydrobio1ogie. 73(3):334-360. 1974.
49
-------
L------
I
32.
35.
24.
u.s. Environmental Protection Agency, Corvallis Environmental Research
Laboratory, Corvallis, Oregon, and Environmental Monitoring and Support
Laboratory, Las Vegas, Nevada. A Compendium of Lake and Reservoir Data
Collected by the National Eutrophication Survey in the Northeast and
North Central United States. Working Paper No. 474, November 1975. pp.
136-158.
25.
Fitzgerald, G. P., and T. C. Nelson. Extractive and Enzymatic Analysis
for Limiting of Surplus Phosphorus in Algae. Journal of Phycology.
2:32-37. 1966.
26.
Wetzel, R. G. Limnology. W. B. Saunders Company, philadelphia, Pennsylvania.
1975. p. 266.
27.
Statistical Policy Division, Executive Office of the President, Office
of Management and Budget. Standard Industrial Classification Manual.
U.S. Government Printing Office, Washington, D.C., 1972. pp. 9-13, 42,
63, 64, 68, 113, 118, 122-125.
28.
MacKenthun, K. M.
mental Phosphorus
613-632.
Eutrophication and Biological Associations. Environ-
Handbook. John Wiley and Sons, New York. 1973. pp.
29.
Taylor, A. W. Phosphorus and Water pollution. Journal of Soil and Water
Conservation, November-December 1967. pp. 228-231.
30.
Muir, J., J. S. Boyce, E. C. Seim, P. N. Mosher, E. J. Deibert, and
R. A. Olson. Influence of Crop Management Practices on Nutrient Move-
ment Below the Root Zone in Nebraska Soils. Journal of Environmental
Quality. 5(3):255-259. 1976.
31.
Tisdale, S. L., and W. L. Nelson. Soil Fertility and Fertilizers. 2nd
ed. The Macmillan Company, New York. 1974. pp. 195-251.
Saehney, B. L., and J. L. Starr. Movement of Phosphorus from
Tank Drainfield. Journal Water pollution Control Federation.
1977 .
a Septic
49:2238.
33.
Viraraghavan, T., and R. G. Warnock. Efficiency of a Septic Tank Tile
System. Journal Water pollution Control Federation. 48:934. 1976.
34.
Considine, D. M. Chemical and Process Technology Encyclopedia. McGraw-
Hill Book Company. New York City, New York. 1974. pp. 1141-1152.
Culp, R. L., and G. L. Culp. Advanced Wastewater Treatment. Van Nostrand
Reinhold Company. New York City, New York. 1971. pp. 293-299.
50
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36.
u.s. Environmental Protection Agency. Process Design Manual for phos-
phorus Removal. EPA 625/1-76-001a, 1976. pp. 3-1 to 3-5, 5-1 to 5-15,
9-1 to 9-7.
37.
prested, B. P., E. E. Shannon, and R. J. Rush. Development of Predictive
Models for Chemical Phosphorus Removal. Volume I. Research Report No. 68.
Environmental Protection Service, Fisheries and Environment of Canada,
Burlington, Ontario. 1977. pp. 1-3, 17-21.
51
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SECTION 5
IDENTIFICATION OF PHOSPHORUS SOURCES
Any attempts to effectively control phosphorus discharges depend on a
thorough understanding of the potential sources and quantities of these dis-
charges and the environment they may impact. Phosphorus is an essential
nutrient and is used in a wide variety of products and applications. phos-
phorus in water can result from natural sources such as plants, natural run-
off and erosion as well as anthropogenic sources including phosphorus manu-
facturing operations, agricultural and urban runoff, sewage, and industrial
uses of phosphorus detergent.
This section contains a primarily qualitative discussion of the sources
of phosphorus. Figure 5-1 shows the environmental cycle of phosphorus. Figure
5-2 outlines the potential phosphorus transport to receiving waters via natural
and anthropogenic pathways. Natural sources are mainly nonpoint discharges
while anthropogenic sources, which encompass agricultural, domestic and in-
dustrial activities, include both point and nonpoint discharges. In many
cases, manufacturing industries are predominantly point sources of phosphorus
discharges while the use of their manufactured products (e.g., fertilizers,
food additives and animal feeds) results in predominantly nonpoint discharges.
NATURAL SOURCES
Although phosphorus is the 11th most abundant element, it comprises oIly
0.1% of the rocks of the earth's crust and is considered a trace element2.
Phosphate deposits are of three types: igneous apatite deposits, sedimentary
phosphorites, and guano and related biological deposits. Marine phosphorites
account for almost 3~!. of the world's phosphate production. Phosphorus in
rocks generally occurs as apatite [CalO(P04)6F2] or in silicates.
Most outcroppings are the result of weathering that has dissolved the
more soluble components surrounding the deposits. The weathering of phosphatic
limestone and dolomite (CaC03MgC03) dissolves carbonates and results in a
"natural" beneficiation of the insoluble apatites. Weathering of phosphatic
limestone can also result in a reprecipitation of solubilized phosphate to
form pebble phosphate deposits.ll Most phosphorus outcroppings are quite
stable with respect to leaching and transport except under acidic conditions.
52
-------
VI
l-"
Decomposition. Burning.
Return Flnws, Other
Agricultural Wastes
Runoff
Source: Adapted from Reference I.
Figure 5-1.
Erosion
leaching
Domestic Use
& Human
Consumption
Marine Waters
Phosphorus transport in the environment.
Uptake &
Accumulatinn
in Natural
Communities
Decomposition
Marine
Sediment
-------
Natural & Grazed Watersheds +r-
NATURAL River Inflow + r-
PHOSPHORUS - -
SOURCES Waterfowl. Fish Fauna. Flora + I--
Air & Direct Rainfall +
r
I Livestock Production +X
I Managed Fnrests +
.
Agricultural I Developed Watershed
+
,... I Fertilizers
+X
ANTHROPOGENIC I Pesticides +X I Receiving I
PHOSPHORUS - I Water
SOURCES
I Other Urban Runoff +X
Domestic I Solid Waste Disposal
.,.
I Human Wastes X
r
I Food Wastes X
I Detergents X
I Inadvertent Sources +X
.
Industrial I Chemical Manufacture
X
I Metal Treatment X
Source: Adapted from Reference I. I Water Treatment XI
.... I Phosphorus Mining +X I
X Point Sources
+ Nonpoint Sources
. Phosphorus Discharges
May Go to Air First and Then to Water
Figure 5-2. Sources of phosphorus in receiving water.
54
-------
Natural sources of phosphorus are considered to be nonpoint sources since
they discharge phosphorus diffusely in general runoff. Natural discharge from
native forests, prairie lands, etc., comprises the "background" phosphorus
level for which there may be little means of or need for control. Other natural
Sources of phosphorus input to receiving waters include pollen, plant residues,
wild animal and bird wastes, natural fires, leaching and both wind and water
erosion from undisturbed watersheds.
Natural and grazed watersheds are uncultivated lands which may support
an animal population. In some instances, a grazed watershed may become over-
grazed which would lead to increased wind and water erosion. Nonpoint phos-
phorus from these areas is mainly a result of soil erosion. Groundwaters, in-
cluding both septic systems and seepage into lakes, generally represent a
negligible source of phosphorus, since most phosphorus is stabilized by pre-
cipitation, adsorption or exchange reactions with the soil~/
Natural sources of phosphorus in the air are small compared to phosphorus
dusts and particulates from human activities. Except for phosphine in marsh
gases, there are no naturally occurring gaseous forms of phosphorus.l/ Spores
and microbes suspended in the air contain some phosphorus, as do particulates
generated from natural fires.
Phosphorus in direct rainfall is roughly proportional to the phosphorus-
containing materials in the air. This water-scrubbing or scavenging of particles
in the air will remove phosphorus either as particulate on the raindrops or
as solubilized phosphorus in them. Data show higher nutrient concentrations
for rainfall in and near urban areas which indicates partial--and in some cases,
very significant--contribution by man,~/ especially in areas of phosphorus-
related industry, e.g., phosphoric' acid and phosphate fertilizer plants.
ANTHROPOGENIC SOURCES
Anthropogenic sources of phosphorus are those generated by human activi-
ties. Most usage of phosphorus is directly related to the phosphorus mining
industry. In 1975, 44.3 million metric tons of phosphate rock were mined in
16 states. Florida contributed 78% of the total with the remainder coming
from Tennessee (5%), North Carolina (3%) and the western states of Utah,
Wyoming, Idaho, and Montana (14%).~/ Phosphate rock mining is a source of both
point and nonpoint discharges. Except in the presence of acid rain or ground-
waters, phosphorus deposits are relatively insoluble. Mining operations create
greater surface areas, however, and can increase the nonpoint contributions.
Any point discharges from mining operations could also have a significant ef-
fect on surrounding waters.
Figure 5-3 shows the major commercial distribution of phosphorus from
mined rock. Agricultural usage (fertilizers and feeds) predominates (80%) with
55
-------
.
Industrial
649.8
15.9%
l
Ferrophosphorus
53. 1
1.3%
Ln
0\
.
Anhydrous
Derivatives
36.8
0.9%
~
Detergent Bui Iders
& Water Treatment
Chemicals
( Sodium
Polyphosphates)
276.4
6.8%
.
Elemental
Phosphorus
596.7
14.6%
t
Phosphate Rock
(31,029x 1Q3MetricTons)
.
Contained Phosphorus
4,087
.
.
Agricultural
3437.2
84.1 %
Defl uori nated
Rock
61.3
1.5%
Normal
Superphosphate
288. 4
7.3%
Wet Process
Phosphoric Acid
2787.3
68.2 %
Elemental
Phosphorus
81.7
20;;
+
Furnace
Phosphoric Acid
478.2
11.7%
.
Other
1070.8
26.2%
Dicalcium
Phosphate
147. 1
3.6%
.
~
+
All Other
(Inc luding Fire
Control Chemicals)
90
2.2°/"
Diammonium
Phosphate
1144 .4
28.0%
Foods, Beverages,
Pet Foods,
Dentifrices
( Calcium
Phosphates)
65.9
1.6%
Figure 5-3.
Acid Treatment
of Meta I
Surfaces
( H3P04)
45.9
1.1 %
Quantities are 103 Metric Tons of Contained Phosphorus
Source: Reference 6
u.s. phosphorus production and domestic consumption (1975).
425.0
10.4%
290.2
7.1 %
Triple
S upe rphosphate
715.2
17.5%
-------
phosphorus detergent builders and other industrial
the majority of the remainder~/ These three areas
93% of the domestic consumption of phosphorus.
applications comprising
combined make up more than
With respect to air emissions, the phosphorus industry and inadvertent
Sources contributed 91% (63,538 MT of phosphorus) of all phosphorus air emis-
sions in 1970l/ (see Table 5-1). Most of this was concentrated near industry;
primarily the fertilizer industry. Eighty-two percent of the phosphorus-
containing air emissions were attributed to the fertilizer manufacturing in-
dustry and identified as calcium and ammonium phosphates~/ phosphorus emitted
to the atmosphere may settle onto land or water surfaces in the form of finely
divided particulate matter or be removed from the atmosphere to the earth's
surface by rain or other forms of precipitation. Table 5-1 lists the principal
phosphorus emissions to the atmosphere from the phosphorus industry and in-
advertent Sources in 1970.
Particulate matter containing phosphorus, when scavenged from the atmo-
sphere by precipitation (e.g., rain and snow), can be an important component
of the phosphorus budget of natural bodies of water. Since the phosphorus con-
tent in particulate matter is relatively constant, the amount of phosphorus
scavenged by precipitation is roughly proportional to the quantity of Bar-
ticu1ate scavenged or to the amount of particulates in the atmosphere.-/ It
has been reported that in 1974 this source contributed one-fifth to one-third
of the phosphorus entering Lake Michigan; of this amount, about 6~!o is at-
tributed to the effects of man and the remainder is considered to be from
natural sources~/ As contributions to bodies of water from other sources are
eliminated, the contributions from the atmosphere become more significant. A
study of sources of phosphorus inputs from the atmosphere for the Chicago,
Illinois, area in 1974 showed that about one-half of the phosphorus removed
from the atmosphere to surface waters was in the form of orthophosphate~/
A summary of estimated phosphorus air emissions generated
basis by individual industries is presented in Section 6. This
the estimated annual quantities and percentage distribution of
phorus discharge as air emissions in 1978.
on a national
analysis shows
total phos-
Agricultural Operations
Agricultural operations are mainly nonpoint sources of phosphorus re-
sulting from the cultivation of soil, the use of fertilizers, livestock man-
agement, and the runoff associated with these activities. Rural land erosion
is the prime contributor of phosphorus to the nation's waterways, with the
greatest transport normally occurring during the spring thaw, snowmelt, and
heavy spring rains. During the spring, the surface soil is sometimes posi-
tioned between melting snow (and/or rain) and frozen ground below. As a re-
sult, manure accumulated at the soil surface in barnyards and pastures dur-
ing the winter is susceptible to transport in runoff waters. Similarly, fields
57
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TABLE 5-1.
PRINCIPAL INDUSTRY SOURCES OF PHOSPHORUS-CONTAINING
EMISSIONS TO AIR - 1970
U.S. Emission
Phosphorus industry (MT P / yea r)f}./ % of U.S.
Triple superphosphate 15,579 22.3
Ammonium phosphate 13,397 19.2
Normal superphosphate 6,808 9.7
Fertilizer application 6,371 9.1
Rock processing 5,237 7.5
Elemental phosphorus 4,320 6.2
Inadvertent sources
Coal combustion 9,033 12.9
Iron manufacturing 2.793 ~
Total 63,538 90.9
Other 6,361 9.1
Source:
Reference 7.
~
Metric tons of phosphorus per year.
58
-------
which are plowed and fertilized in the fall in preparation for spring plant-
ing are also vulnerable to fertilizer loss (if the chemicals are not incor-
porated deeply enough in the soil) and soil erosion. In addition to erosion
by water transport, these cultivated fields are also vulnerable to wind ero-
sion during dry years when vegetation or snow cover (or soil moisture--in more
southern climates) is insufficient to hold the soil in place. In all of these
cases, nonpoint phosphorus loading to surface waters increases~/
In agricultural watersheds, soil management practices, types of crops,
and the fertility level of the eroded soil greatly influence the nutrient
load from runoff. Sod or cover crops and reduced tillage can help alleviate
this erosion.
The agricultural use of organophosphorus pesticides represents another
nonpoint source of phosphorus. Organophosphorus pesticides are applied at
rates of 2 to 14 kg of active ingredient (AI) per hectare (ha) per year in
various agricultural uses.!!/ Approximately 11% of the AI is phosphorus.
Consequently, the total phosphorus loading to agricultural land receiving
these chemicals is ~ 0.2 to 1.5 kg/ha/year. Considering the small loading per
unit area, the limited mobility of phosphorus in soil, and the hydrolysis of
some portion of the pesticide to esterified phosphates which are not avail-
able as plant nutrients, the contribution of phosphorus (especially ortho-
phosphate) to nonpoint runoff from pesticide use appears to be insignificant~/
Most phosphorus in the soil (e.g., fertilizers, pesticides, or naturally
occurring rock) may be temporarily stabilized by the formation of iron or
aluminum phosphates or calcium phosphate, depending on the pH of the soil.
This phenomenon reduces transport of phosphorus to groundwaters and other
receiving waters. The phosphorus is carried to receiving waters by sediment
(consisting of silt, clay, and organic matter) as a result of erosion of agri-
cultural land, feedlots; forests, grasslands, etc. Organic matter is partic-
ularly susceptible to erosion because of its low density~/ Soil erosion losses
nationally have been variously estimated as about 19.8 to 27 MT/ha/year; in
extreme cases, losses of 133 MT/ha/year or more are recorded.~/ Sediments (or
suspended solids) are considered a pollutant in their own right, but they also
represent a significant mechanism for the transport of phosphorus in the form
of fertilizers and, to a lesser extent, pesticides to the nation's surface
waters. Vollenweider has estimated that 1 to 5% of the fertilizer used reaches
surface waters.!l/
Omernik found that from 41 to 50% of the total phosphorus in runoff from
agricultural nonpoint drainages was soluble orthophosphorus (based on from 68
to 295 drainages investigated in each USe category).14/
59
-------
Table 5-2 shows some values for total phosphorus watershed loading by
land form and land use in the United States. The type of soil texture had a
significant influence on the degree of phosphorus loading for plowed fields,
grassland, and dairy pasture. The highest loading values applied for the fine
textured soils. In terms of land use, the lowest phosphorus export was re-
ported from wetlands, forests, and grasslands. The land uSes which involved
plowing the soil, plowed fields and truck crops, were shown to have the
highest phosphorus losses. In regard to both soil texture (land form) and land
use, phosphorus export was directly related to the vulnerability of the soil
to erosion.12./
TABLE 5-2. TOTAL PHOSPHORUS WATERSHED LOADING BY LAND USE
AND LAND FORM IN U.S. (kg/km2/year)
Land form
Fine textured Medium. textured Coarse textured
Land use Level Sloping Level Sloping Level Sloping
Plowed fields 106 125 87 87 23 63
Grassland 23 23 10 10 10 10
Dairy (pasture) 40 63 23 23 10 10
Brush 23 23 23 23 23 23
Orchard/truck crops 125 125 125 125 125 125
Forest 10 10 10 10 10 10
Wetlands 0 0 0 0 0 0
Source:
Adapted from Ref. 15.
Detergents
The use of phosphorus in detergents is a major production and consumption
category. About 15% of the domestic phosphate rock supply was used in elec-
tric furnace production of elemental phosphorus in 1975 and about 58% of this
phosphorus was used via phosphoric acid in the production of sodium phosphates
for detergent builders and water treatment. Sodium tripolyphosphate (STPP)
accounts for more than 80% of the sodium phosphates.!Q/ The non-STPP synthetic
detergents and surfactants and the availability of STPP for use in synthetic
detergents lead to the rapid replacement of soaps in the market place in the
1950's.
60
-------
Phosphates are used in synthetic detergents to enhance cleaning proper-
ties. The predominant use is in powdered detergents for home laundry, but phos-
phates are also used in liquid and automatic dishwashing detergents and
miscellaneous household cleaners. Industrial and institutional (1&1) consump-
tion of phosphates is considerably less than the household usage. Due to the
outstanding and irreplaceable properties of phosphorus in the 1&1 cleaners,
exemptions for applications in janitorial, industrial and metal cleaning have
been made in some detergent phosphate regulations.
Although phosphate detergents and cleaners represent a small volume of
total phosphorus consumption compared to fertilizers, their usage is widespread
and they present fairly constant input to waste treatment systems, since
virtually 100% of each compound is discharged. These chemicals are a poten-
tially controllable source and many efforts have been made to decrease phos-
phorus loads from detergents, including state and local phosphate detergent
bans, voluntary reductions in phosphorus concentrations by manufacturers, and
research and development on phosphorus substitutions.
Over the past decade, there has been a significant reduction in the phos-
phorus content of household laundry products in the United States. This re-
flects industry's reduction of phosphorus concentrations in detergents from
about 12.8% in 1967 to a current 1978 average of 7.4% (Based on MRI's best
estimates). Lower detergent phosphate concentrations are planned up to the
early 1980's, if suitable substitutes (e.g., zeolites) are used. A phosphorus
concentration of about 3% might result if zeolites enter the detergent mar-
ket.!L/
The main sources of phosphorus emissions from the manufacture of soaps
and detergents are the spray-drying operations. In these operations, liquid
formulations are dispersed into a stream of hot gas in the form of a mist of
fine droplets. Moisture is rapidly vaporized from the droplets, leaving resid-
ual particles of dry solid, which are separated from the gas stream. On the
average, approximately 72% of the industry's production is powdered formula-
tions from spray dryers. Depending on the efficiency of air emissions control
procedures used, this may represent a significant local source of phosphorus
contamination.
Food
Some wastewaters from food processing industries, which convert agricul-
tural crops to food products, contain high levels of phosphorus as shown in
Table 5-3. For example, press water from beet sugar factories is reported to
have a total phosphorus concentration ranging from 31 to 274 mg P/liter, and
potato starch in wastewater results in a phosphorus level of 27 to 80.5 mg/
liter.18/ Because of the high phosphorus concentrations, these wastewaters can
be quite important on a local basis.
61
-------
TABLE 5-3.
PHOSPHORUS CONCENTRATION IN INDUSTRIAL WASTEWATERS
Type of waste
PZ05
(rng/liter)
Total P
(rng/liter)
Beet sugar factories
Washing water
Press water
6-30
71-629
2.6-13
31-274
Potato starch
Malt-house
Brewery
Slaughterhouse
Flaying-house
Flax retting
Dairy (waste volume four
times the volume of milk
handled)
63-184
30
46.5
18.7
100
60
20
27 -80.5
13
20.2
8.2
43.7
26.1
8.7
Source:
Adapted from Ref. 18 (as reproduced in Vollenweider, 1970,
Ref. 13).
Another source of phosphorus pollution in wastewaters is food formulation
and processing plants. The processing of food products which contain substan-
tial amounts of phosphorus (i.e., meat, fish, dairy products, some vegetables)
will result in losses of phosphorus to plant wastewaters. The phosphorus con-
tent of these wastewaters is further heightened by the presence of detergent
used in routine washdowns of processing areas and equipment. Some losses of
phosphorus-containing chemicals used in leavening systems (particularly mono-
calcium phosphate), antioxid,nts, and buffers would also be expected from
food processing activities.] No attempt was made in this study to conduct a
detailed analysis of these phosphorus sources.
Sewage
Domestic sewage contains nutrients, bacteria, and organic matter derived
from human wastes which contain phosphorus from foods and pharmaceuticals,
washing wastes from home laundry detergents and cleaners and automatic dish-
washing compounds, wastes from residences (including garbage disposals),
business, and institutions, and in many cases urban runoff. In 1970, total
daily per capita contribution of phosphorus waS estimated at 1.5 to 3.0 g,
62
-------
with phosphorus input to municipal waste treatment systems estimated to be 20%
industrial and 80% residential~/
Table 5-4 lists household sources of phosphorus in sewage processed in
municipal treatment plants. This breakdown points out the significance of both
detergents and human wastes. These two sources represent consistent input to
waste treatment systems. The contribution from laundry detergents and miscel-
laneous household sources ~ 50% of total phosphorus input) could be altered
by formulation changes using phosphorus substitutes.
TABLE 5-4.
PHOSPHORUS INPUT TO MUNICIPAL WASTE TREATMENT
SYSTEMS FROM HOUSEHOLDS
Source
Contained phosphorus
(kg/capita/year)
Reference
Laundry detergents
Human waste
Miscellaneous (garbage disposal
waste, dishwater, etc.)
0.40-0.96
0.40-0.5~/
0.20
1, 13
1,13,17
17
Total
1.00-1.70
,2./
Three additional values cited in Reference 13 fall within the range of
these two values.
Septic Tank Systems
The most widely utilized method of on-site domestic waste disposal is the
septic tank-soil absorption system~/ The use of these systems continues to
increase significantly. In 1977 over 50 million people in the United States
used septic tank systems to dispose of their domestic wastes.20/
One study on the transport of septic tank effluent to groundwater has
shown that very limited phosphorus migration occurs.ll/ Since much of the
phosphorus is in the form of orthophosphates,~/ many types of soil particles
interact with and immobilize these phosphates~/ For example, clay materials
and oxides of iron and aluminum strongly adsorb phosphates, and calcareous
type (limestone) soils react with phosphorus to form hydroxyapatite. Under
proper conditions, nearly complete removal of the phosphorus in septic tank
wastewater occurs in the vicinity of the tile fields. The highest degree of
phosphorus transport has been identified in aquifer materials comprised of
coarse sand or gravel~/ One septic system location where significant phos-
phorus transport might occur involves siting a septic system immediately
63
-------
adjacent to a water body or a stream in an unsuitable aquifer material. In the
determination of appropriate sites for septic tank systems, increased emphasis
should be placed on soil and groundwater characteristics.~/
Some septic tank systems in the United States may pose a significant phos-
phorus pollution problem. It is not known how many septic tank systems are
operated improperly or are located where they allow phosphorus to discharge
to surface waters.
Other
Chemical manufacture results in point sources of phosphorus as air emis-
sions which are generally scrubbed, or wastewater discharges which typically
go to either municipal or in-house treatment. In most cases these industrial
chemicals are produced from high purity electric furnace phosphoric acid. Some
of the main products include food additives and animal feeds while much of the
elemental phosphorus is used in manufacturing inorganic chemicals such as
P20S for oil additives, insecticides, desiccants, and organic phosphorus com-
pounds; PC13 for insecticide intermediates, chlorinating and reducing agents,
plasticizers, and numerous other chemicals.3,24/
Phosphoric acid and acid phosphates are used in metal cleaning, finishing
and polishing. Other applications involve deoxidizers for copper and its
alloys, electroplating and phosphatizing~/ Wastewater from these operations
is commonly treated in-plant for partial removal of phosphorus and other pol-
lutants before being discharged from plant areas.25,26/
The increase in industrial use of cooling water has resulted in greater
use of water treatment chemicals containing phosphorus. Phosphorus loss from
this source is generally a point source discharge to municipal treatment
systems.
Human activities in urban areas contribute to both point and nonpoint
phosphorus discharges. Urban runoff includes phosphorus from lawn and garden
fertilizers and pesticides. Also included in this category are wastes from the
nation's pet population, phosphorus deicing compounds and other small sources.
Solid waste disposal can contribute phosphorus via landfills or open
dumps. Phosphorus, which contacts surrounding soils, normally undergoes reac-
tion with the soil to stabilize the phosphorus and result in negligible
~ransport. A few disposal sites utilize liners or other means of containment
to prevent the escape of other more hazardous materials, and simultaneously
prevent any possible phosphorus transport as well. With proper management,
phosphorus losses from landfills and solid waste disposal can be prevented.
64
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REGIONAL DIFFERENCES IN PHOSPHORUS DISCHARGES
According to Tennessee Valley Authority (TVA) data on regional consump-
tion of plant nutrients (Table 5-5), 26% and 29% of total P205 in commercial
fertilizers is used, respectively, in the East North Central states and in the
West North Central states.~/ The South Atlantic states use about 11% of the
total and 1~1o is applied in the West South Central states. Thus, these four
regions collectively account for the consumption of about 76% of the commercial
phosphate fertilizers in 1976. These data are a good indication of areas in
the United States where transport of phosphate fertilizers to surface waters
could be a problem. Their impact would result primarily from agricultural run-
off.
Phosphate management should consider regional water quality, since areaS
can vary widely in their specific environmental characteristics, phosphorus
problems and phosphorus sources. Regional differences are illustrated in Ta-
ble 5-6 in a comparison of the phosphate sources in the Potomac River Basin,
the Alafia River in Florida and Lake Erie. This is an extreme example of the
diverse nutrient loading conditions which must be understood before any effec-
tive phosphate management can begin.
In 1971, detergent phosphates contributed 65% of the municipal wastewater
phosphorus to the Potomac, while the mining industry was the prime source of
phosphorus in the Alafia River, with only 4% of the total phosphorus load being
attributed to all municipal waste.28/ Lake Erie received 35 to 5~1o of its total
phosphorus load from detergents. These detergents comprised 70 to 8~1o of the
total phosphorus from industrial and municipal sources. While a ban on phos-
phate detergents would have little impact on the amount of phosphorus entering
the Alafia River, it would seem a more plausible alternative for the other two
areas.
TRENDS AFFECTING PHOSPHORUS DISCHARGES
A comparison of phosphate rock usage, shown in Table 5-7 for 1972, 1973,
and 1974, shows a relatively constant distribution through all product cate-
gories. Projections for phosphate rock consumption through 1980 show increases
in the ma~or categories; their percentages of the total, however, are fairly
constant~/ The total is expected to increase from 3.2 to 4.1 to 4.2 million
metric. tons of phosphorus, with fertilizers, builders and water treatment
chemicals, and feeds comprising approximately 77, 8.1, and 8.6%, respectively.
65
-------
TABLE 5-5.
ESTIMATED REGIONAL CONSUMPTION OF P205 IN COMMERCIAL
PHOSPHATE FERTILIZERS APPLIED IN 1976
Region or state
States included in region
Total fertilizer
P205 consumed, %
of total for u.s.
New England
Middle Atlantic
South Atlantic
East North Central
West North Central
East South Central
West South Central
Mountain
Pacific
Alaska
Hawaii
Puerto Rico
Total
Maine, New Hampshire, Vermont,
Massachusetts, Rhode Island,
Connecticut
New York, New Jersey, Pennsylvania,
Delaware, Maryland, West Virginia
Virginia, North Carolina, South
Carolina, Georgia, Florida
Ohio, Indiana, Illinois, Michigan,
Wisconsin
Minnesota, Iowa, Missouri, North and
South Dakota, Nebraska, Kansas
Kentucky, Tennessee, Alabama,
Mississippi
Arkansas, Louisiana, Oklahoma,
Texas
Montana, Idaho, Wyoming, Colorado,
New Mexico, Arizona, Utah,
Nevada
Washington, Oregon, California
Not applicable
Not applicable
Not applicable
0.75
4.75
10.66
25.82
29.04
7.59
10.13
5.11
5.58
0.01
0.44
0.12
100.00
Source:
Adapted from Reference 27.
66
-------
TABLE 5-6.
REGIONAL VARIATIONS IN PHOSPHATE LOADING
Municipal (%) Industrial (%)
Potomac River 78.0 8.6
A1afia River 4.0 96.0
Lake Erie 68.5 7.3
Land runoff (%)
13.4
24.2
Source:
Reference 28.
TABLE 5-7. ANNUAL TRENDS IN PHOSPHORUS PRODUCTS
(x 103 MT phosphorus)
Use/year 1972 % 1973 % 1974 %
Fertilizer 9,355 80 9,818 79 10,914 79.4
Detergents and waste- 936 8 915 7.4 1,017 7.4
water chemicals
Animals feeds 467 4 544 4.4 605 4.4
Foods 467 4 544 4.4 605 4.4
Other 467 4 544 4.4 605 4.4
To tal 11,692 12,365 13,746
Source: Reference 29.
67
-------
Production in 1976 showed a decline in thermal phosphoric acid (following
a sharp decline in 1975) with a subsequent increase in wet-process acid pro-
duction.30/ The thermal process requires large amounts of electrical power;
therefore, increasing power costs have made this process economically unattrac-
tive. Triple superphosphate was stable, normal superphosphate declined, and
ammonium phosphates were showing continued growth.
Efforts have been made to improve the purity of wet-process acid since
the dry process requires additional pollution control equipment and approxi-
mately five times as much energy.~/ Although the purity of wet-process acid
is generally not high enough for food applications, it can be used in deter-
. gents, and animal feeds. These data are consistent with earlier projections
which showed wet-process phosphoric acid as the main source of growth in the
fertilizer industry.
The usage of builders and wastewater chemicals reflects the
detergent industry trends to reduce phosphorus concentrations in
ucts.
soap and
their prod-
CURRENT ACTIVITIES
The 1972 Great Lakes Water Quality Agreement between the United States
and Canada is an attempt to restore and enhance the water quality of the
Great Lakes. The control of phosphorus entering the Great Lakes is a major
activity under this agreement.31-33/ Emphasis has been placed on reducing the
phosphorus concentration in detergent formulations, evaluating nonpoint source
discharges and possible solutions, and controlling point sources by placing
a 1 mg/liter phosphorus limit on municipal treatment plant effluents in the
lower Great Lakes Basin (plants with a capacity greater than 1 million gal-
lons per day). Extensive surveillance programs have been active in obtaining
data which are used to formulate recommendations and implementation programs.
Most recommendations to the International Joint Commission (IJC) include
continued and increased monitoring programs (for both point and nonpoint
sources) along with additional efforts to remove phosphorus and develop alter-
native builders. The data resulting from these endeavors should continue to
increase the understanding and control of eutrophication in the Great Lakes
and other areas as well.
The Research Advisory Board of IJC established a phosphorus task force
to identify more accurately the phosphorus sources draining into the basin
states and evaluate control methods. This should be a significant source of
continuing data on phosphorus loading.
68
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REFERENCES TO SECTION 5
1.
Porcella, D. B., A. B. Bishop, J. C. Andersen, o. W. Asplund, A. B.
Crawford, W. J. Grenney, D. I. Jenkins, J. J. Jurinak, W. D. Lewis,
E. J. Middlebrooks, and R. M. wa1kingshaw. Comprehensive Management of
phosphorus Water pollution. EPA-600/5-74-010, U.S. Environmental Pro-
tection Agency, Washington, D.C., 1974.
2.
Griffith, E. J., A. Beeton, J. M. Spencer, and D. T. Mitchell (eds).
Environmental phosphorus Handbook. John Wiley and Sons, New York, 1973.
3.
Van Wazer, J. R. Phosphorus and Its Compounds. Volume 1 Chemistry.
Interscience Publishers, Inc., New York, 1958.
4.
Ferguson, F. A. A Nonmyopic Approach to the Problem of Excess Algal
Growths. Environmental Science and Technology, 2(3):188-193, March
1968.
5.
Rawlings, G. D., E. A. Mullen, and J. M. Nyers. Source Assessment:
Phosphate Fertilizer Industry--Phosphoric Acid and Super Phosphoric
Acid. EPA-600/2-77-107, U.S. Environmental Protection Agency, Washington,
D.C., 1977. p. 8.
6.
U.S. Bureau of Mines. Mineral Facts and Problems - Phosphate Rock.
Bulletin No. 667, 1975. p. 819-827.
7.
GCA Corporation. National Emissions Inventory of Sources and Emissions
of Phosphorus. EPA-450/3-74-013, U.S. Environmental Protection Agency,
1973.
8.
Murphy, T. J. Sources of phosphoric Inputs from the
Significance to Oligotrophic Lakes. Water Resources
port No. 92. Final Report to U.S. Department of the
A-065-r11, September 1974.
Atmosphere and Their
Center Research Re-
Interior Project No.
9.
Uttormark, P. D., J. D. Chapin, and K. M. Green. Estimating Nutrient Load-
ings of Lakes from Non-point Sources. EPA-600/3-74-020, U.S. Environ-
mental Protection Agency, August 1974. pp. 13-47.
10.
Bigger, J. W., and R. B. Corey. Agricultural Drainage and Eutrophication.
Eutrophication: Causes, Consequences, Correctives. National Academy of
Sciences, washington, D.C., 1969. pp. 404-445.
11.
von Rumker. R., E. W. Lawless, A. F. Meiners, K. A. Lawrence, G. L. Kelso,
and F. Horay. Production, Distribution, Use, and Environmental Impact Po-
tential of Selected Pesticides. EPA-540/1-74-001, U.S. Environmental Pro-
tection Agency, 1974. pp. 157-195.
69
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18.
12.
Carter, L. J. Soil Erosion: The Problem Persists Despite the Billions
Spent on It. Science, 196:409, April 22, 1977.
13.
Vollenweider, R. A. Scientific Fundamentals of the Eutrophication of
Lakes and Flowing Waters, with Particular Reference to Nitrogen and
Phosphorus as Factors in Eutrophication. Publication No. DAS/CSI/6827.
Organization for Economic Cooperation and Development, paris, 1970.
14.
Omernik, J. M. Nonpoint Source--Stream Nutrient Level Relationships:
A Nationwide Study. EPA-600/3-75-l05, u.S. Environmental Protection
Agency, Corvallis, Oregon, 1977. p. 28.
15.
Johnson, M. G., J. C. Comeau, T. M. Heidtke, W. C. Sonzogni, and B. W.
Stahlbaum. Management Information Base and Overview Modeling. Inter-
national Reference Group on Great Lakes pollution from Land Use Activities.
International Joint Commission, Toronto, Ontario, Canada, August 1978.
p. 15.
16.
F. A., and M. K. Moran. Faith, Keyes, and Clark's Industrial
Fourth edition. John Wiley and Sons, New York, 1975. pp. 628-
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Chemicals,
657.
17.
Fealey, T. Personal Communication. Proctor and Gamble, Cincinnati, Ohio.
Organization for Economic Cooperation and Development. Treatment of Mixed
Domestic Sewage and Industrial Waste Waters in Germany. Muller (1966) (as
reproduced in Vollenweider, 1970, Ref. 13).
19.
Scalf, M. R., W. J. Dunlap, and J. F. Kreissl. Environmental Effects of
Septic Tank Systems. Report Prepared for the Robert S. Kerr Environmental
Research Laboratory, Office of Research and Development, U.S. Environmental
Protection Agency, Ada, Oklahoma.
20.
Sawhney, B. L., and J. L. Starr. Movement of Phosphorus from
System Drainfield. J. of Water pollution Control Federation,
November 1977.
a Septic
p. 2238,
21.
Jones, R. A., and G. F. Lee. Septic Tank Wastewater Disposal Systems
as phosphorus Sources for Surface waters. Occasional Paper No. 13,
Center for Environmental Studies, University of Texas at Dallas, July
1, 1977.
22.
Brandes, M. Effective Phosphorus Removal by Adding Alum to Septic Tank.
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31.
32.
23.
Ellis, B., and
Ferti lization.
Michigan Water
K. E. Childs. Nutrient Movement from Septic Tanks and Lawn
Technical Bulletin No. 73-5, Deparbnent of Natural Resources,
Resources Commission, Lansing, Michigan, 1973.
24.
Cross, J. A., D. M. Epp, T. L. Ferguson, A. R. Hylton, A. F. Meiners,
C. E. Mumma, R. E. Roberts, and C. J. W. Wiegand. The Role of Phosphorus
Control in Verification of a Ban on Nerve Agent Production. An Economic
and Technical Analysis. Volume II ACDA/E-204, ST-215, January 1973.
25.
Metal Finishing Guidebook Directory for 1977. published by Metals and
plastics, Inc., Hackensack, New Jersey, 1977, pp. 734-740.
26.
Beall, J. F., and R. McGathen. Guidelines for Wastewater Treatment. Part
I. How to Minimize Wastewater. Metal Finishing, 75(9):13-17, September
1977 .
27.
Hargett, N. L. "1976 Fertilizer Sut1U1lary Data. National Fertilizer
ment Center, Tennessee Valley Authority, Muscle Shoals, Alabama,
Y-112, March 1977.
Deve10p-
Bulletin
28.
Grundy, R. D. Strategies for Control of Man-Made Eutrophication. Envi-
ronmental Science and Technology, 5(12):1184-1190, December 1971.
29.
Data from a client-private information service.
30.
Harre, E. A., M. N. Goodson, and J. D. Bridges. Fertilizer Trends 1976.
National Fertilizer Development Center, Tennessee Valley Authority,
Muscle Shoals, Alabama, Bulletin III, March 1977.
Great Lakes Water Quality Board. 1976 Annual Report submitted to the
International Joint Commission. July 1977.
International Reference Group on
Activities. Joint Summary Report
COt1U1lission. September 1977.
Great Lakes pollution from Land Use
- Task B to the International Joint
33.
Great Lakes Research Advisory Board. Annual Report to the International
Joint Commission. July 1977.
Additional information on selected topics may be obtained from the following
sources.
Department of the Interior, U.S. Geological Survey. Development of
Phosphate Resources in Southeastern Idaho. Final environmental impact
statement (FES 77-37), September 16, 1977.
71
-------
Effluent Guidelines Division, Office of Water and Hazardous Materials,
U.S. Environmental Protection Agency. Development Document for Proposed
Effluent Limitations Guidelines and New Source Performance Standards for
the Animal Feed, Breakfast Cereal, and Wheat Starch Segments of the Grain
Mills Point Source Category. EPA 440/1-74-039, September 1974.
McElroy, A. D., S. Y. Chiu, J. W. Nebgen, A. D. Aleti, and F. W. Bennett.
Loading Functions for Assessment of Water Pollution from Nonpoint Sources.
EPA-600/2-76-l5l, U.S. Environmental Protection Agency, Washington, D.C.,
1976. pp. 102-106.
MCElroy, A. ~., J. W. Nebgen, A. D. Aleti, and S. Y. Chiu. National
Assessment of Water pollution from Nonpoint Sources. Draft of Final
Report. EPA Contract No. 68-01-2293, U.S. Environmental Protection
Agency, Washington, D.C., 1975.
Office of Toxic Substances. The Hazard of Phosphates in the Environment.
Draft Report. U.S. Environmental Protection Agency, Washington, D.C.,
1977. 68 pp.
Rossenblatt, D. H., M. J. Small, and J. J. Barkley. Munitions Production
Products of Potential Concern as Waterborne Pollutants - phase I. Report
No. 7307, AD 912752, U.S. Army Medical Environmental Engineering Re-
search Unit, Edgewood Arsenal, Maryland, June 1973.
72
-------
SECTION 6
QUANTIFICATION OF PRINCIPAL PHOSPHORUS SOURCES
The principal sources of phosphorus released
scribed in Section 5. The quantitative results of
discussed in this section.
to the environment were de-
this study are presented and
The quantification study discussed in this section has resulted in
estimates of quantities of total phosphorus discharged to the environment. An
exhaustive study of every phosphorus source was beyond the scope of this re-
port. Thus, some minor sources of phosphorus emission were not addressed in
these quantification estimates.
RESULTS OF THE NATIONAL ASSESSMENT
The methodology and results of the quantification of phosphorus emissions
from nonpoint and point sources are presented in the following subsections.
Nonpoint Sources of Phosphorus
A draft report, "National Assessment of Water pollution from Nonpoint
Sources", was completed in 1975 for the EPA.1I That study was conducted in
two phases: (a) development of loading functions and (b) calculation of non-
point pollution loads for the United States. The report addressed the follow-
ing pollutants: nitrogen, phosphorus, BOD, sediment, coliforms, radioactivity,
salinity, heavy metals, acid mine drainage, and pesticides. The results of that
report were used as the principal data base for nonpoint sources in this study.
For purposes of this study, the discussion is limited to pollutants which
are actually delivered to surface waters. Pollutants that are transported
within a land source, but never reach surface waters are not considered. In
addition, pollutants transported to subsurface waters that are not a part of
the surface water inventory are not classified in this study.
Methodology and Results for Estimating Nonpoint Emissions--
A brief discussion of the methodology used and results obtained in esti-
mating the phosphorus emissions from nonpoint sources follows under separate
headings.
73
-------
Cropland. pasture and rangeland. and forestland--Emissions of phosphorus
from these sources were calculated by an approach in which the estimated quan-
tities of phosphorus contained in eroded sediments were summed for the various
sources. The analysis was based on the Universal Soil Loss Equation (USLE),
which predicts soil loss from sheet and rill erosion. The USLE contains param-
eters which account for the influence of rainfall, erodibility of soils, topog-
raphy, and the nature of ground cover and cultural practices.l/ Data on these
parameters were obtained from numerous sources, notably U.S. Department of Agri-
culture (USDA) compilations of information on soils, topography, soil cover,
and tillage or management practices. The phosphorus content of soils for the
United States was taken from data for PZ05 concentrations in the top 30 cm (1
ft) of soil in the 48 conterminous states.l/
Although more than 30 years old, these data for the broad general regions
of the country were within the same ranges as later data of this type reported
in selected soil surveys conducted since 1946. Analysis of fertilizer usage
patterns indicated that the contribution of phosphorus to nonpoint loads
through fertilizers was small compared to the contributions from phosphorus
originally in the soil. The analysis also showed that fertilization is required
to maintain natural phosphorus concentrations in soils.
The phosphorus concentration of eroded sediments is increased relative to
that observed in the original soil, since an enrichment of phosphorus content
occurs during transport. An enrichment factor of 1.5 was employed uniformly
in the calculations. Enrichment implies that phosphorus is preferentially as-
sociated with the more erodible, fine-grained soil particles which are in
greater abundance in sediment.
Not all soil lost from a field is delivered to a body of water. For this
reason, a delivery ratio of less than one was used to reduce soil loss (and
consequently, phosphorus) to a smaller value actually delivered to streams.
The delivery ratio was estimated on an area-by-area basis as a function of
distance to streams and soil properties. The delivery ratio used represents
delivery to the edge of receiving streams. In-stream processes, such as sedi-
mentation and benthic accumulation, were excluded from the study. Thus, the
estimated phosphorus loads tend to be larger than those measured at the mouth
of a watershed, particularly when the drainage area in the watershed is large.
The other major data required consisted of area-by-area information on
land uses, such as areas and types of cropland and data on soils, topography,
cover and related factors. The land use and conservation practices were ob-
tained from the USDA's Soil Conservation Service, 1967 Conservation Needs
Inventory.
74
-------
In summary, the method used to estimate nonurban, nonpoint loads of phos-
phorus was based on the premise that phosphorus is primarily delivered to
streams in a nonsoluble form which accompanies eroded sediments. The amount of
delivered sediment was estimated using the USLE modified by a delivery func-
tion; the phosphorus content of delivered sediments was calculated from soil
phosphorus concentrations modified by an enrichment factor. Land use and re-
lated information were obtained principally from the 1967 Conservation Needs
Inventory. The smallest land unit considered was the county; loads were esti-
mated for each county for a variety of land uses and then aggregated to larger
units (i.e., states).
The estimated pollution loads from cropland, pasture and
forestland are summarized in Table 6-1. A brief discussion of
ing to nonpoint phosphorus pollutant loads by specific source
rangeland, and
factors contribut-
follows.
Erosion of soil and associated organic matter following agricultural cul-
tivation is an extensive source of water pollution.if Farmland was classified
in terms of row crops, close grown crops, rotation hay and pasture, hayland,
orchards, and temporarily idled cropland. This source represents approximately
480 million acres of land area in the continental United States.if
The extent of sediment erosion from cropland varies in response to a num-
ber of variables: type of crop; rainfall and runoff; soil characteristics;
topography; type of tillage; and conservation practice. Sediment acts as a
transport agent for potential pollutants such as plant nutrients (e.g., phos-
phorus and nitrogen), crop residues containing organic matte~ and pesticides
containing phosphorus. Compounds of phosphorus may be either absorbed on, or
initially existing in soil particles. Thus, if the soil is eroded into a water
course, phosphorus may be carried along and contribute to pollution of water.
Approximately 211 million hectares of land area in the continental United
States are used as grassland pasture and range.if This acreage, as defined in
this study, also includes acres in farmsteads and country roads.
Well~anaged pasture and rangeland can provide good cover which protects
soil from erosion. Releases of sediment and other pollutants from land in
these uses are, therefore, generally low when compared to those for cropland.
Sources of phosphorus in pasture and rangeland runoff include animal wastes,
organic matter, and phosphorus bound in the eroded soil.
Forestlands are treated as a combination of recently harvested forest,
logging roads, undisturbed commercial forest and noncommercial forests.if Pol-
lutant loads from forested lands are expressed in this report as a single load
for all of these subclasses.1l Sources of phosphorus in forestland runoff are
organic matter (e.g., leaves, decaying vegetation, and humus), wild animal
wastes, and phosphorus bound in the eroded soil. As with other categories of
75
-------
Table 6-1.
E::;TUIATED NATIONAL NONPOTNT SOURCE DISCHARGES OF TOTAL
PHOSPHORUS TO nil-. ENVTRONNENT TN PRECIPITATION RUN-
OFF AND AIR ENISSlON::> IN 1 'i7~
Source activity or area
Estimated Jischarges
Discharged tu water.!.!
~rr of tutal P/year Land
(rounded to nearest area
lUO tuns) (106 ha)
to environment
Kilogram of p/
ha/year
Air Emission~/
(~IT of total pfyear)
A.
Runoff discharKes
Cropland
Pasture and rangeland
Forestland
Livestock feedlotS
Urban runoff
Roadway runo If
Subtotal
IJ.
lnadvert-.:nt
sources
"-J
(j\
Windblown soil
Fertilizer applicatiun
(field spreading)
Agricultural bundng
Forest fires
Subtutal
National total, nunpoint
source
1,4J3,400
985,600
84,301)
28,700
l8,40U
1,000
2,551,400
2,551,400
195.3
211.1
246.1
0.0836
6.1
Not avai lable
natd not applicable
Dat" not aJ'plicable
Data not applicable
nata not applicable
7.34
4.67
0.34
343.30
3.02
Not available
Data not applicable
Data not applicable
DaLa not applicable
Data not applicable
Data not applicable
Data not applicable
6,300
4,800
3,600
6,700
21,400
Sources:
References 1 and 4.
21,400
-------
land use, the primary mode of phosphorus transport is the erosion of soil and
associated organic matter both of which contain phosphorus.
Livestock feedlots--Estimates of phosphorus emissions from feedlots in-
cluded only those feedlots smaller than 1,000 head of beef cattle or equiva-
lent numbers for other animals in confined feeding. The larger feedlots were
considered to be point sources regulated by point source guidelines.!!
The basic method consisted of: (a) a method to estimate runoff from feed-
lots based on precipitation characteristics of a region; (b) selection of rep-
resentative values, from published data, of concentrations of phosphorus in
feedlot runoff; (c) calculation of feedlot sizes (areas, and numbers of live-
stock) from information on numbers of livestock on feed in lots of different
sizes in the smallest or most representative geographic or political area; and
(d) summation of the area or regional loads to the appropriate areas, such as
the state.
Uncontrolled livestock feedlots are sources of concentrated wastes and,
if improperly managed, these wastes can result in substantial pollution loads.
The emission data shown in this report (Table 6-1) apply to uncontrolled feed-
lots (i.e., 1,000 head or less).
Animal wastes deposited on the surface of feedlots are usually accumulated
and compacted by movement of the livestock, and are transported beyond the feed-
lot site whenever storm runoff occurs. Several factors affect the magnitude and
quality of such runoff: storm intensity and duration; antecedent moisture con-
dition; nature. of the feedlot surface, and the density of animals per unit
area.17
During runoff, pollutants on the feedlot surface are dislodged and trans-
ported either in solution or in suspension toward a discharge point, such as a
stream, lake, or reservoir. Because of trapping, interception, and other ob-
stacles, some of the suspended pollutant in runoff does not reach the surface
waters. Also, phosphorus pollutants in solution are, in part, trapped or other-
wise attenuated because of percolation and leaching. Therefore, the net loads
delivered are always smaller than the amounts of pollutants generated on the
feedlot site.!!
Urban runoff--The basic source of information for urban runoff was several
studies on the rates of deposition and subsequent wash-off of pollutants in
representative urban areas. Available data were categorized for different urban
land uses--residential, commercial, light and heavy industry, and open land.
Demographic, urban land use characteristics, and urban area data were employed
to calculate street lengths (expressed as curb~iles) for urban areas. Loading
data per curb~ile derived for the various urban land uses were combined with
street curb lengths to calculate loadings of phosphorus for each urban center.
An urban area was defined as an incorporated town or city having a population
of 25,000 or more in the 1970 census.
77
-------
The pollutant loads carried in the urban runoff have been estimated for
847 cities.lf These cities comprise a total land area of about 14.7 million
acres. Table 6-1 shows the total estimated phosphorus loading from urban .run- .
off.
Urban storm water may pick up wastes on both pervious and impervious sur-
faces and, thereby, contribute to pollution of receiving waters. The origins
of this phosphorus pollution in urban areas are discarded litter, automotive
exhaust and fuel leakage, organic debris from tree leaves and grass trimmdngs, .
dust and fly ash from industrial facilities, lawn fertilizer and pesticides,
pet wastes, etc.
Rural roadway runoff--A phosphorus deposition rate (1.44 x 10-6 Ib of phos-
phorus) per axle-mile was employed in calculation of phosphorus emissions from
roadways. Other needed data were miles of highway by state or other region of
interest, and highway traffic volumes. The traffic data were obtained from the
Federal Highway Administration and from state reports of vehicular traffic. In
Texas and California, for example, daily rural vehicular traffic mileages for
the period of record were 132 and 141 million miles, respectively.
Combination of such data along with the distribution of vehicle types were
used to generate axle-mile estimates, which were multipled by the above specified
phosphorus deposition rate to calculate phosphorus emissions.
Table 6-1 shows the estimated phosphorus loading from rural roadway run-
off. The runoff from highways and highway rights-of-ways contains significant
amounts of oil, fuel residues, heavy metals, dust and dirt, tree leaves and
grass trimmings. The sources of these pollutants may be: vehicles, road sur-
face materials, atmospheric fallout, erosion and runoff from adjacent areas,
litter and spills.lf The studylf estimated phosphorus pollutant deposition
relative to use of rural roadways by motor vehicular travel.
Air Pollution from Nonpoint Phosphorus Sources--
Inadvertent sources account for the significant phosphorus air emissions
in the nonpoint category as shown in Table 6-1.
The data base used in this assessment of phosphorus air emissions from
nonpoint sources was taken from Reference 4. These data were updated so as to
apply as estimated values for 1978. The updating procedure consisted basically
of adjusting the emissions level to correspond by direct proportion to the
estimated changes in consumption of phosphorus-based material from the base
year (1973) to 1978.
78
-------
L
Data obtained fram the literature indicate that the field spreading of
phosphate fertilizers accounts for an air emission rate of 2 kg Pz05/metric
ton (MT)* of applied ferti1izer.2! In 1978, the estimated total field applica-
tion of normal superphosphate, triple superphosphate and the ammonium phos-
phates was 5,530,000 MT.
Since PZ05 is 43.64% phosphorus, the estimated total phosphorus emission
to the air due to field spreading is approximately 4,800 MT/year calculated as
(2 x 5.530.000 x 0.4346) .
\ 100 .
Comparison of Estimated Nonpoint Emissions with PLUARG Data--
The methodology used to estimate phosphorus loads from rural areas in-
volves numerous assumptions and provides only long-term average results. Gen-
erally, phosphorus loads for most watersheds are not available in the United
States. However, considerable work has been done in the Great Lakes Basin. It
is, therefore, interesting to compare the results obtained there with those
estimated in this report.
For the Great Lakes Basin, the MRI National Assessmentl! obtained the fol-
lowing unit loads:
Cropland
pasture/range
Forest
3.55 kg/ha/year
2.57 kg/ha/year
0.1 kg/ha/year
In 1978, the International Reference Group on Great.Lakes Pollution
Use Activities (PLUARG) reported~/ the following ranges of measured
their pilot watersheds:
for Land
values for
Crop
Improved
pasture
Forested/
woodland
0.2-4.6 kg/ha/year
0.1-0.5 kg/ha/year
0.02-0.67 kg/ha/year
*
Throughout this section, values will be given in terms of kg/metric ton (MT).
Phosphorus conversion factors pertinent to the calculations in this section
are given in Appendix A. Descriptions of the typical methodology used. to
calculate the estimated total phosphorus emissions from industrial point
sources are presented in Appendix B.
79
-------
The MRI estimates fall within the observed range for cropland and forest;
the estimate is higher for pasture and range. This generally good agreement
lends credibility to the methodology used in the assessment. However, in com-
paring the two sets of numbers, two facts should be kept in mind. First, the
PLUARG results are based on 2 years of data; the MRI results are long-term
statistical averages generated for use with the Universal Soil Loss Equation.
The PLUARG report noted that a single large storm in the Maumee Basin caused
a lOO-fold increase in sediment yield in 1975 as compared with 1976.21 Since
observed sediment/phosphorus yields in a watershed are intimately connected
to the character of the actual rainstorms involved, short-term averages can
give misleading results, either high or low, as compared with a long-term aver-
age. Second, the MRI results are loadings to the nearest streambank; PLUARG
measured rivermouth loads, which should be smaller (substantially so, if the
watersheds involved are large).
Point Sources of Phosphorus Discharge
The major point sources of phosphorus discharge to the environment, dis-
cussed in Section 5, are quantified on an estimated basis in this section. The
aggregate of these industrial point source discharges and municipal effluents
is estimated to account for at least 93% of the total phosphorus discharge from
all United States phosphorus-consuming industries. The 21 point sources which
were addressed in this study and the corresponding SIC numbers are shown in
Table 6-2.
Each activity listed in Table 6-2 is evaluated and discussed in the fol-
lowing subsections. Each analysis includes a process flow diagram, a brief
discussion of process technology and mass balance, and a description of the
nature and estimated emission factors for phosphorus discharges to the envi-
ronment in wastewater, atmospheric emissions and solid wastes. Finally, a
national emission estimate, which quantifies principal point sources, is de-
veloped and described. The results for all national point sources are pre-
sented in Table 6-17, p. 157.
All data on quantification of phosphorus sources are presented in
of total phosphorus (i.e.. kilogram of total phosphorus per metric ton
product). All quantification estimates apply for 1978.
terms
of
Mining and Beneficiation of Phosphate Rock (SIC No. 1475)--
Phosphate rock mining and processing is conducted in four regions of the
United States. The reported contribution of each area to the total output for
1975 is: (a) Florida, 78%; (b) North Carolina, 5%; (c) Tennessee, 5%; and (d)
Western States (Utah, Wyoming, Idaho, and Montana), l2%~/
80
-------
TABLE 6-2.
POINT SOURCES OF PHOSPHORUS EMISSIONS TO AIR AND WATER
SIC No.
Point source activity
Commercial production industries
1475
2874
2874
2874
2874
2874
2048
2048
2819
2819
2819
2819
2819
2819
2841
2819
2841
2819
2819
None
None
None
Mining and beneficiation of phosphate rock
Wet-process phosphoric acid
Superphosphoric acid
Normal superphosphate
Triple superphosphate
Ammonium phosphate
Defluorinated phosphate rock (livestock and poultry feeds)
Animal-feed-grade calcium phosphates
Elemental phosphor4s .
Dry-process phosphoric acid (furnace process)
Phosphorus pentoxide
Phosphorus trichloride
Phosphorus oxychloride
Phosphorus pentasu1fide
Sodium phosphates
Food-grade calcium phosphates
Laundry detergents (phosphorus-based)
Direct acid treatment of metal surfaces
Phosphorus-based water treatment chemicals
Municipal sewage treatment .
Inadvertent sources
Food processing
Sdurce:
Re f. 8 .
81
-------
Domestic operations are categorized by type of production as (a) Eastern
processes and (b) Western processes. These operations are discussed below under
separate headings.
Eastern processes--A representative flow diagram describing this process
is shown in Figure 6-1; process details are discussed in Reference 7.
Effluent wastewaterll--Wastewater streams associated with Eastern
phosphate rock production are shown below.
Waste
Source
Disposition
Primary slimes (3
to 5% solids)
Des1iming cyclones
Settling ponds
Secondary slimes
Ho1ding~tanks, sec-
ondary des1iming
Settling ponds
Sand tailings (20
to 30% solids)
Flotation cells
Mined out areas for
land reclamation
Mine pit seepage
Mine
An intermittent and
indeterminate vol-
ume discharged to
a slimes or tail-
ings waste stream
Dust scrubber
slurry
Dryers
Discharged to waste
streams
The treatment of process wastewater streams consists basically of
gravity settling through the extensive use of ponds.
Effluents are intermittently or continuously discharged from the
pond settling area by the ore beneficiation facilities. The discharged volumes
of effluents are affected by (a) the degree of water reuse in processing, (b)
total amount and frequency of rainfall, (c) surface runoff, and (d) available
settling pond capacity.
Effluents typically include not only excess water from the process
recycle system, but also various quantities of incidental water. An analysis
of data for a total of 18 eastern facilities (located in Florida, Tennessee
and North Carolina) shows that the average discharge of total phosphorus (as
phosphate) amounts to 0.047 kg/MT beneficiated ore. It is assumed that 50% of
the producers discharge and that because of rainfall patterns, this discharge
occurs for a period of 2.5 months each year (Martin, W., Personal Communication,
82
-------
Condi tioner,
Flotation
I (Primary) I
I I
I I
~-------.t_-----------
Air Emission
Ni I for F Jorida
0.03 kg P for other Eastern States
Screen
and
Wash
Mine
Slimes
Removal
(X)
w
~-
I
I I
IE}:
I I
1..-. Screen J
Legend:
Alternate Route No.1
- - - - AI ternate Route No.2
Recycle
Water
Water
De-Oil
Conditioner.
Flotation
( Secondary)
I
I
I
I
--_..J
Total Phosphorus Loss per MT Beneficiated Ore
Air = 0.09 kg P/MT (Florida)
= O. 12 kg P/MT (Other Eastern States)
Water = 0.005 kg P/MT
Intermittent
Wastewater
Discharge
0.005 kg P on
Annual Basis
Source:
Reference 7.
Figure 6-1.
r. Air Emission,
Ore Handling
and Dryi ng
Atm. 0.09 kg P
Vent
Fi Iter
and/or
Dryer
Product
1 MT
. Recycled Water
to Process
Flow diagram for phosphate ndning and processing--Eastern states.
-------
EPA, Effluent Guidelines Division, Washington, D.C., January 1978). Thus, es-
timated phosphorus discharge on an annual basis is about O.OOS kg phosphorus
per metric ton of beneficiated phosphate ore.
Atmospheric emissions--Ernissions occurring during mining and bene-
fication of eastern phosphate ore were estimated on the basis of data in Ref-
erence S. These data are summarized in Table 6-3. Except where otherwise noted
all subsequent calculations on atmospheric emissions were made by the follow-
ing methods.
Mining--The wet mining operations used for Florida land-pebble
phosphate rock produce essentially no particulate or phosphorus emissions.
In open-pit mining of hard rock phosphate in Tennessee and North
Carolina, the ore mining, loading and hauling cause air emissions of small
amounts of phosphate rock particulates. Assuming the P20S content of particu-
lates emitted to the air to be the same as that in the phosphate ore, this air
emission can be estimated in the following manner. The uncontrolled particulate
emission factor is 0.2S kg/MT of beneficiated ore, the P20S content in the ore
is 26% and there is no emission control. Thus, the phosphorus emission can be
estimated to be approximately 0.03 kg phosphorus per metric ton of beneficiated
ore.
Beneficiation--Phosphorus air emissions occurring in the bene-
ficiation process are estimated as follows.
For ore handling, the uncontrolled particulate emission factor
is O.S kg/MT product, the P20S content in the emission is 30%, and the level
of emission control is SO%. The estimated emission is 0.03 kg phosphorus per
metric ton of beneficiated ore.
For drying of the phosphate rock concentrate, uncontrolled
emissions are 7.S kg particulate per metric ton of beneficiated phosphate ore,
the particulate contains 30% P20S, and the emission control is 94%. The esti-
mated emission is 0.06 kg phosphorus per metric ton of beneficiated ore.
Summary of phosphorus losses
losses to the environment from Eastern
1 MT of beneficiated ore) follows:
to environment--Data on phosphorus
phosphate mining and processing (basis,
Total atmospheric losses for Florida
Total atmospheric losses for other
Eastern states
0.09 kg P/MT
0.12 kg P/MT
Total wastewater losses for all
Eastern states
O.OOS kg P/MT
84
-------
TABLI:: 6-3.
SOURCI::S AND ESTIMATI::S OF PHOSPHORUS-CUNTAINING AIR EMISSIONS
FOR EASTERN AND WESTERN PIIOSPHATI:: ROCK mNINC AND
BI::NEFICIATION
Production activity
IIlIcon t ro Ll "d
particulate
end ssion
factor
(kg 1m)
% P205
in
emissions
Estimated
level of
emission
cont ro 1
Total phosphorus
emissions--
after controls
(kg p/~IT product)
Comments
(%)
Eastern producers
Hining
ore handling
Drying
Tota 1
ex>
lJ1
W"stern producers
Hining
Crushing and grinding
Drying
Ga lCining-coo Ii ng
Total
0.25
0.5
7.5
0.25
10
7.5
20
26
30
30
26
30
30
30
o
50
~4
0.03
0.03
0.06
Not applicable to Florida
wet-mining operations
0.12
Route
!:!2.:..J..:!.1
Route
No. 2.:!.1
o 0.03 0.U3
97 0.04 0.04
94 0.06 NA
95 NA 0.13
0.13 0.20
SOUTCt::
Rl'''. OJ.
:!I
Sec ~'igure 6-2.
-------
Western processes--Figure 6-2 presents a description of the representa-
tive mining and beneficiation operations for Western producers. Details of this
process are discussed in Reference 7.
Eff1uenL wusLewuLer--The raw wasLe 1011ds from the WesLern processes
consist of slimes and tailings which are sent to settling ponds. For the WGter
recycle process, the high net evaporation rate which applies for this region
of the United States makes it feasible for these plants to have no discharge
of wastewater effluent to the environment. In the mining area around all plants,
the only wastewater occurring is normal surface runoff. Thus, it is concluded
that there is essentially no discharge of effluent wastewater by Western pro-
ducers.
Atmospheric emissions--Emissions which occur during Western phosphate
rock mining and beneficiation operations were estimated on the basis of data
taken from Reference 5. The calculation methods were the same as those de-
scribed earlier for Eastern producers. Emission data developed in these esti-
mates are summarized in Table 6-3. The estimated total air emissions are 0.13
and 0.20 kg phosphorus per metric ton of beneficiated ore for Route Nos. 1 and
2, respectively. The process steps used in routes are shown in Figure 6.2.
Summary of phosphorus losses
losses to the env~ronment from Western
1 MT of beneficiated ore) follows:
to environment--Data on phosphorus
phosphate mining and processing (basis,
Total atmospheric losses
Route
Route
Total
No.1 (Figure 6-2)
No.2 (Figure 6-2)
wastewater losses
0.13 kg p/MT
0.20 kg p/MT
o kg p/MT
National emissions for mining and beneficiation of phosphate rock--In
1976 the total domestic marketable production of phosphate rock was reported
to be 44,451,800 MT (49 million short tons).21 Production is estimated to in-
crease to 56,245,200 MT (62 million short tons) in 1980.21 Assuming a uniform
growth rate from 1976 to 1980, the production level for 1978 can be estimated
to be 50,348,000 MT (55.5 million short tons).
For
mated as
effluent
all Eastern operations, the emission loss in wastewater can be esti-
approximately 220 MT phosphorus per year. There is no discharge of
wastewater from the plants of Western producers.II
There are no significant air emissions from Florida wet-mining opera-
tions.1! In North Carolina and Tennessee, the open-jet-mining of hard rock
creates some air emissions. Also, the ore handling and drying operations for
all Eastern ores contributes to phosphorus air emissions. Thus, the total air
I .
!
86
-------
Air Emission
0.03 kg P
Air Emission
0.04 kg P
Crush
Mine
Recycle Water
i~r
I I
L Scrubber ~
ex>
-..J
legend:
Alternate Route No.1
-- --Alternate Route No.2
Source:
Reference 7.
Figure 6-2.
Tofal Phosphorus Loss per MT Beneficiated Ore
Air;: 0.13 kg P/MT by Route 1
Air = 0.20 kg P/MT by Route 2
Water = 0 kg P/MT
Screen,
Mill and
Classify
r----------....,
I I
I ,
.J Water L
...,
I
I
L.
Atm.
Vent
0.06 kg P
Drying
Slimes
Remova I
Atm. Vent
O. 13 kg P
Product
1 MT
Calcining --. Product
1 MT
Flow diagram for phosphate mining and processing--Western states.
Conditioner
Flotation
Recycle
Water
-------
emissions factor is 0.12 kg phosphorus per metric ton of beneficiated ore
(Table 6-3). The overall phosphorus discharge (air emission) for Eastern op-
erations can be estimated to be 5,320 MT phosphorus per year. .
For Western operators, it was assumed (Lehr, J. R., Personal Communica-
tion, Tennessee Valley Authority, Muscle Shoals, Alabama, October 1977) that
about 70% of the operations use the alternate process route and that 30% use
the regular process route (Figure 6-2). On this basis, the weighted emission
factor is 0.18 kg phosphorus per metric ton of beneficiated ore. Thus, the
estimated annual air emission is 1,100 MT phosphorus.
The total wastewater emissions are estimated to be 220 MT phosphorus an-
nually and the estimated air emissions are 6,420 MTphosphorus per year.
Wet Process Phosphoric Acid Production (SIC No. 2874)--
The manufacturing process (dihydrate process), shown in a representative
flowsheet in Figure 6-3, is the sole source of fertilizer phosphoric acid in
the United States. This acid is used as a raw material in the production of
triple superphosphates and ammonium phosphate fertilizers. Aqueous sulfuric
acid is reacted with ground phosphate rock to convert the tricalcium phosphate
to orthophosphoric acid as shown in the following reaction.lO.ll!
CalO(P04)6F2 + 10H2S04 + 20H20
) 10CaS04.2H20 + 6H3P04 + 2HFt
Insoluble calcium sulfate dihydrate (gypsum) and hydrofluoric acid are also
produced. The gypsum is separated from the acid and discharged to a pond, which
also serves as a recycle water basin. Most of the released HF is recovered in
an exhaust gas scrubber. The weak phosphoric acid is concentrated in an evap-
orator to yield a product containing about 54% P205. Detailed descriptions of
this process are given in the literature.lO.ll!
Material balance data11!--The material requirements on the basis of 1 MT
of phosphoric acid (54% P2050r 75% H3P04) plus about 3 MT of waste gypsum are:
beneficiated phosphate rock (14% phosphorus), 1.8 MT (0.252 MT phosphorus);
and sulfuric acid (94%), 1.7 MT. Overall yield of H3P04 based on phosphorus
content of raw material is 95%. A phosphorus mass balance showing values which
apply for 1 MT of phosphoric acid product follows:
88
-------
Phosphorus Values per MT Product
Input P = 252 kg P
Output P ~ 235.7 kg P
Atm Losses = O. 166 kg P
Water Losses = 0.009 kg P
Beneficiated 1.8 MT
Phosphate 252 kg P
Rock
Atm Emission
O. 156 kg P
Unloading,
Grinding,
Transfer
Contaminated
Water
STREAM LEGEND
-.- Major Solid
Major Liquid
Minor Liquid
---- Minor Gas
I
.
11 ,000 - 14,500 I/MT
Sulfuric Acid
-93 % H2S04
55 - 70 %
H2S04
---,
J
I
I
I
_1-
I Off.GaS ~--. ta Atmosphere
O. 01 kg P
I
I
I
I
I
I
Contaminated Water
5,400-6,300 I/MT
Sulfuric
Acid
Dilution
Water
5,400- 6, 300 I/MT
III
III
Q)
U
o
...
0..
o
.....
11 , 000 - 14 , 500
""C
Q)
Contami nated ~
u
I/Mf Water ~
...
(16,400 - 20,800 I/MT) ~
c
~
Product
H3P04 (54% P205)
1 MT
235.7 kg P
I ntermi ttent
Wastewater
Discharge
O. 009 kg P on
Annual Basis
Source:
Reference 10.
Figure 6-3.
Flow diagram for production of wet-process phosphoric acid.
89
-------
Input
Phosphate rock
252 kg P
Outputs
Product
Total wastewater losses
Atmospheric losses from
unloading, grinding,
and transferring p
rock
Atmospheric losses from
wet scrubber
235.7 kg P
0.009 kg P
0.156 kg
P~
0.01 kg p j
Total atm.
losses,
0.166 kg P
Total P
losses,
0.175 kg
Unaccounted for P
16.125 kg P
Wastewater effluent--The three types
wet-process acid plants are: (a) contact
ing water, and (c) steam condensate.ll/
of wastewater streams generated at
process water, (b) noncontact cool-
Contact process water is defined as water which comes into direct contact
with process materials during the manufacturing operations. Sources of contact
process wastewater include scrubber liquor, gypsum slurry, barometric condens-
ers (for reactor) and acid sludge. Recycled gypsum pond water is utilized in
the scrubber system to remove particulates, fluorides, and phosphates from the
gas streams. This contact wastewater, combined with the steam condensate, con-
tains varying quantities of phosphoric acid along with fluorides, sulfates and
gypsum.ll/ The insoluble gypsum particles contain a small amoune of phosphorus.
Data which define the extent of wastewater disposal or containment prac-
tices in the domestic phosphate fertilizer industry have been reported in the
literature.lO/ As shown in Table 6-7 (page 110), only about 12% of all domestic
wet-process plants discharge wastewater to the environment, and two-thirds of
these facilities add lime to remove phosphorus prior to discharge. Facilities
with no wastewater discharge contain their effluent in specially designed gyp-
sum ponds or abandoned phosphate rock mining pits. At some plants, scrubber
liquor is sold for fertilizer or fluorine recovery.ll/
The permissable phosphorus concentrations in thi.s effluent under the EPA
effluent limitation guidelines for best practicable technology currently avail-
able (BPCTCA) is a maximum average discharge for 10 or more consecutive days
of 35 mg of total phosphorus per liter.lQ/ This discharge value was used in
estimating the total phosphorus discharge in effluent from wet-process acid
plants.
90
-------
i
As shown in Figure 6-3, the contaminated water input to the gypsum pond
ranges from 16,400 literslMT PZOS to ZO,800 literslMT of PZOS in the product.
Assuming the average flow is 18,600 liters/MT of PZOS in product, the annual
phosphorus discharge from the gypsum pond can be estimated to be 0.0088 kg
phosphorus per metric ton of phosphoric acid.
It was assumed that for those plants which discharge effluent, the total
discharge period each year is Z.S months (Martin, W., Personal Communication,
EPA, Effluent Guidelines Division, Washington, D.C., January 1978).
Atmospheric emissions--Dust losses to the atmosphere occur during the
handling and grinding of phosphate rock. The dust particles contain phosphorus
in the form of tricalcium phosphate.
Off-gases containing some phosphoric acid mist and other particulate emis-
sions are treated in a wet-scrubber as a means of reducing air emissions. Most
of the phosphorus in the gas stream is removed in this scrubber unit and trans-
ferred to a wastewater stream. Recycled gypsum pond water is used in the wet-
scrubber system.
Particulate emissions from the reactor are comprised of unreacted phos-
phate rock, and lesser amounts of insoluble salts and gypsum. These particles
are entrained in reactor gases vented to the wet scrubber. About 80% of the
particulate matter consists of water-soluble phosphorus compounds.!11
Estimates relating to total phosphorus air emissions in the wet process
for production of phosphoric acid are summarized in Table 6-4. The estimating
procedures are described below; the estimated emissions apply for 1 MT of prod-
uct (wet process phosphoric acid).
Grinding of phosphate rock--The uncontrolled particulate emission
is 10 kglMT of product. The PZOS content in the emission is 3Z% and the level
of emission control is 97%.il From this, estimated phosphorus emission is 0.04
kg phosphorus per metric ton product.
Material handling--For unloading phosphate rock, the average con-
trolled emission factor is O.lS g particulate per kilogram of P20S in prod-
uct.ill The rock contains 3Z% P20S. One metric ton of product acid contains
S40 kg of PZOS. Then, the estimated phosphorus emission is 0.113 kg phosphorus
per metric ton product.
For phosphate rock transfer and conveying, the reported controlled
emission factor is 0.04S g particulate per kilogram of P20S in product.ill The
estimated phosphorus emission is 0.003 kg phosphorus per metric ton product.
91
-------
TABLE 6-4.
SOURCES AND ESTIMATES OF PHOSPHORUS-CONTAINING AIR EMISSIONS
FOR WET PROCESS PHOSPHORIC ACID PRODUCTION
Production activity
Uncontrolled
particulate
emission
factor
(kg/Mr product)
Controlled emission factor
Grams of particu- Grams of P205
late/MT of per MT of
P205 inP205 in
product product
% P205
in
emissions
To ta 1
P emissions
after controls
(kg p/Mr product)
0.040
Grinding phosphate rock
Material handling:
Phosphate rock unloading
Phosphate rock transfer
and conveying
\0
N
Wet scrubber system
Total
10
NA
NA
NA
NA
NA
32
32
32
NA
0.113
0.003
0.01
Source:
References 5.and 13.
0.166
0.15
0.045
NA
NA
NA = Not available.
NA
0.038
-------
The total estimated phosphorus emission caused by material handling
is approximately 0.12 kg phosphorus per metric ton product.
Wet scrubber svstem--The reported average overall controlled emis-
sion factor for this system is 0.038 g of P205 per kilogram of P205 in prod-
uct.ll/ The estimated phosphorus emission is approximately 0.01 kg phosphorus
per metric ton product.
National emission for wet-process phosphoric acid production--The esti-
mated wastewater emission factor is 0.0088 kg phosphorus per metric ton and
the estimated production level in 1978 is 6,600,000 MT (Table 6-17); the emis-
sion is estimated to be 58 MT phosphorus.
The air emission factor is 0.166 kg phosphorus per metric ton. Thus, the
total air emission is calculated to be 1,095 MT phosphorus.
Superphosphoric Acid Production (SIC No. 2874)--
When orthophosphoric acid (54% P205)' produced by the wet-process, is
heated at elevated temperatures a molecular dehydration occurs and po1yphos-
phoric acid chains are formed. For example, tripo1yphosphoric acid can be pre-
pared as fo11ows:ll/
3H3P04 ---+H5P3010 + 2H20
The product, a mixture of orthophosphoric acid and dehydrated acids of differ-
ing chain lengths, is called superphosphoric acid. Wet process superphosphoric
acid is concentrated to 68.5 to 72% P205.11/ A representative process flow
diagram is shown in Figure 6-4. .
The commercial processes used in the United States are (a) submerged com-
bustion and (b) vacuum evaporation. About 75% of the existing domestic plants
use the latter process.ll/ Superphosphoric acid is used in the preparation of
high analysis phosphate fertilizers.
Mass balance data--A phosphorus mass balance showing values which apply
for 1 MT of product superphosphoric acid follows:
Input P
Output in product
Atmospheric losses
Wastewater losses
305.507 kg P
305.5 kg P
0.007 kg P }.
o kg P
Total P
losses, 0.007 kg
Wastewater effluent--Wastewater streams are discharged from barometric
condensers, steam-jet ejectors, and wet scrubbers in superphosphoric acid
plants. These streams contain orthophosphoric acid and fluorides.l3/
93
-------
Steam
Water from Gypsum Pond
Phosphori c Ac i d
305.507 kg P
L-
o
....
e
o
Cl.
o
>
w
Steam
L-
CI1
0'>
C
o
...c
u
x
w
Condensate
....
o
CI1
:r:
Phosphorus Values per MT Product
Input P == 305.507 kg P
Output P == 305.5 kg P
Atm Losses == 0.007 kg P
Water Losses == 0 kg P
Source:
Reference 13.
Figure 6-4.
Barometric
Condenser
Seal
Water
Pump
Steam Jet
Ejector
Concentrated
Phosphoric Acid
1 MT, 305.5 kg P
(70% P205)
Air Emission
0.007 kg P
Hot Well
Gypsum Pond
and Recycle
System
Flow diagram for production of superphosphoric acid.
94
-------
Data in Table 6-7 indicate that none of superphosphoric acid plants dis-
charge wastewater.
Atmospheric emissions--Emission species include fluoride compounds and
particulates. Particulates are lilnited to liquid phosphoric acid, aerosols,
and mists. One plant has reported particulate emissions ranging from 0.011 to
0.055 g/kg P205.11/ The estimated phosphorus emission, based on these data,
is 0.01 g phosphorus per kilogram P205 in product. If it is assumed that the
product contains 70% P205, then the estimated phosphorus emission (per metric
ton of superphosphoric acid) is 0.007 kg phosphorus.
National emission for superphosphoric acid production--No wastewater is
discharged from this production process.13/
Based on emission factors and production data shown in Table 6-4 the
national air emission can be estimated to be 4 MT phosphorus.
Normal Superphosphate Production (SIC No. 2874)--
A representative flowsheet for the domestic production of normal super-
phosphate (NSP) is given in Figure 6-5. The produ~tion of NSP basically in-
volves the reaction of ground phosphate rock with sulfuric acid to form mono-
calcium phosphate according to the overall reaction:~/
CalO(P04)6F2 + 7H2S04 + 17H20 ~ 7CaS04.2H20 + 3Ca(H2P04)2.H20 + 2HF1'
The process involves four steps: (a) preparation of phosphate rock; (b)
mixing of phosphate rock with sulfuric acid; (c) curing and drying of the
original slurry by completion of the reactions; and (d) excavation, milling,
screening, and bagging of the finished NSP product. During the processing
operations, no attempt is made to separate the calcium sulfate from the mono-
calcium phosphate. Thus, the presence of the calcium sulfate results in a
relatively impure fertilizer product. Detailed descriptions of this process
are given in the literature.lO,ll/
Material balance data--The weight ratio of phosphate rock to finished NSP
product is 0.605:1 when the feed material contains 34.3% P205 (or 14.98% phos-
phorus).ll/ On this basis, 1 MT of product is equivalent to 0.605 MT (605 kg)
of phosphate rock. It was assumed that the average P205 content in the product
is 19% (or 8.29% phosphorus).!l! Then, the product shown on the f10wsheet con-
tains 82.9 kg phosphorus and the phosphate rock contains 90.6 kg phosphorus.
A phosphorus mass balance showing values which apply for 1 MT of product
normal superphosphate is as follows:
95
-------
Air Emission
O. 1 kg P
Cone~-
Sulfuric Acid!
Water
\0
'"
Gas
Containment
Enclosure
(Dotted Li nes)
I
"1
L
Un loadi ng ,
Grinding,
Feedi ng
Ground Phosphate Rock
605 kg
90.6 kg P
I Mixer
Exhaust Gas
----
Cutter 0
Conveyor
Curing
Bui Iding
Phosphorus Values per MT Product
Input P = 90.6 kg P
Output P = 82.9 kg P
Atm Losses = 0.47 kg P
Water Losses = 0.007 kg P
Source:
Reference 10.
Figure 6-5.
Recycled Water
O. 15 kg P
Gas Discharged to Atm
Scrubber
Raw
Wastewater
Exhaust Gas 940 to 1040 liters
Holding Pond
Treatment Unit
Pu Iverizer
Intermittent
Wastewater
Discharge
0.007kg P on
Annual Basis
Screen ing
Air
Em ission
0.22 kg P
Bagging
Product, 1 MT
82.9kgP
Flow diagram for production of normal superphosphate.
-------
Input P
90.6 kg P
Outputs
Product
Wastewater discharge
Atmospheric losses
from unloading,
grinding, and
feeding Pore
Atmospheric losses
from wet scrubber
Atmospheric losses
from bagging
82.9 kg P
0.007 kg P
0.1 kg P
Total water effluent)
losses, 0.007 kg P ~
j
Total P losses,
~~7~
0.15 kg P
Total atm.
losses, 0.47 kg P
0.22 kg P
Unaccounted for P
7.22 kg P
Wastewater effluent--Current information on the wastewater containment
practices and the extent of wastewater disposal in the phosphate fertilizer
industry has been described. Inquiries reportedly made to 80% of the domestic
NSP fertilizer plants have shown that only 4% discharge wastewater (see Table
6-7).11/ This survey indicated that practically all of the discharging plants
treat their wastewater with lime to remove most of the contained phosphorus,
before discharging the effluent to surface waters. On the basis of this in-
formation, it was assumed in this study that a holding and treatment pond is
provided for each fertilizer plant operation and that wastewater is impounded
and recirculated in the plant. Also, it was assumed that the phosphorus con-
tent in the treated effluent from NSP plants corresponds to the EPA effluent
limitation guidelines for best practical control technology currently avail-
able (i.e., a maximum average discharge for 10 or more consecutive days of 35
mg total phosphorus per liter of wastewater).lQI It was further assumed that
for those plants which discharge effluent, the total discharge period each
year would be 2.5 months.
The range of discharge rates of contaminated wastewater from the wet
scrubber is 940 to 1,040 liters/MT of NSP product.lO/ Assuming an average flow
rate of 990 liters/MT, the estimated discharge of phosphorus in wastewater to
the environment is calculated to be 0.035 kg total phosphorus per metric ton
product. For a 2.5~onth period of discharge each year, the annual phosphorus
release in wastewater would be 0.007 kg/MT of NSP.
Atmospheric
. (see Figure 6-5)
ment, the curing
ging.14/
emissions--In NSP production plants, the air emission points
are the ore grinding operation, the mixer, conveying equip-
building, materials handling, product pulverizing, and bag-
97
-------
The particles emitted from NSP processing range from finely divided rock
phosphate to finished fertilizer.if Phosphate rock particles tend to be large,
and therefore, usually settle near the emission point. Phosphate rock particles
contain tricalcium phosphate in concentrations from lS to 80% equivalent weight
of P20S. This phosphate is stable and essentially insoluble in water.
Estimates of the phosphorus losses from atmospheric releases to the envi-
ronment during NSP production were based on information contained in References
Sand 14. Data developed in these estimates are tabulated in Table 6-S. The
estimating procedures used are described below; all estimates are based on 1 MT
of NSP product.
Grinding of phosphate rock--The uncontrolled particulate emission
is reported to be 3 kgfMT of product.if The particulate contains 34% P20S' the
level of emission control is 80%, and the emission is calculated to be 0.09 kg
phosphorus per metric ton product.
Material handling--The average controlled emission factor for unload-
ing phosphate rock is 0.28 g of particulate per kilogram of P20S in product.14f
The phosphate rock contains 34% P20S and the product contains 19% P20S. The
estimated phosphorus emission is 0.008 kg phosphorus per metric ton product.
For phosphate rock feeding, the controlled emission is reported to
be O.OSS g of particulate per kilogram of P20S in product.14f The estimated
phosphorus emission is 0.0016 kg phosphorus per metric ton product.
Mixer and den--A reported controlled emission factor for this source
is 0.26 g of particulate per kilogram of P20S in product.14f The estimated
phosphorus emission is 0.004 kg phosphorus per metric ton product.
late per
0.OS7 kg
Curing building--The controlled emission factor is 3.6 g of particu-
kilogram of P20S in product.14f The estimated phosphorus emission is
phosphorus per metric ton product.
Product grinding--The uncontrolled particulate emission factor is
0.2S kg of P20S per metric ton product,if and the level of emission control
is 80%. The phosphorus emission is estimated to be 0.02 kg phosphorus per
metric ton product.
Product screening--The estimated uncontrolled emission factor is
1 kg of particulate per metric ton of product and the level of emission con-
trol is 8S%.2/ The emission is estimated at 0.07 kg phosphorus per metric ton
product.
98
-------
TAllL~ 6-5. SOURCES AND ESTIMATES OF PJlOSPIIOIWS-CONTAININC AIR EMISSIONS
FOR NORMAL SUPEKPJlO::;PJlATE PkOOIlCTION
Production activity
uncontrolled
particulate
emission
factor
(kg/ill product)
Controlled
emission factor
(g of particulate
per 1 Mf P205 in
produ.ct)
Estimated
level of
emission
control
"I. PZ05
in
Tutal
p ~missi()ns
after controls
(kg P/MT product)
(%)
emissions
Grinding phosphate rock
Material handling:
Phosphate rock unload-
ing
Phosphate rock feedi ng
Mixer and dell
Curing building
Product grindillg
\0
\0
Product screelling
Product b
-------
Product bagging or bulk loading--The reported controlled emission
factor is 0.5 kg P205 per metric ton product.if The estimated emission is 0.22
kg phosphorus per metric ton product.
National emission for NSP production--About 4% of the domestic producers
discharge wastewater.13!
The annual wastewater emission based on the estimated emission factor
(0.0007 kg phosphorus per metric ton product) and the 1978 production rate
(390,000 MT) shown in Table 6-17 can be calculated to be < 0.1 MT phosphorus.
Based on the tabulated data shown in Table 6-16, the estimated annual
phosphorus discharge in air emissions can be calculated at 183 MT phosphorus.
Triple Superphosphate Production (SIC No. 2874)--
The two principal types of commercial triple superphosphate (TSP) are
granular (GTSP) and run-of-the-pile grade (ROP-TSP). The processing conditions
and physical characteristics differ significantly for these two products. The
GTSP product is a hard, uniform, pelletized granule whereas the ROP-TSP product
is a nonuniform pulverized mass. The GTSP process accounts for about 60% of
total TSP production, and the ROP process is used for the remaining 40%.14f
Both processes use the same raw materials, ground phosphate rock and wet-
process phosphoric acid. The basic chemical reaction is:
CalO(P04)6F2 + l4H3P04 + 10H20
) 10Ca(H2P04)2.H20 + 2HF
The similarity between the two processes ends at this point. For a detailed
description of the technology for these processes the reader is referred to
References 10 and 11. An analysis and discussion of each process follows.
The GTSP process--Figure 6-6 presents a representative flow diagram for
this process. A relatively low strength (40% P20S) phosphoric acid is used in
the reaction with phosphate rock. The low strength acid maintains the resul-
tant slurry in a fluid state and permits the chemical reaction to proceed
further toward completion before it solidifies. This slurry is transferred to
a granulator which produces pelletized material. These pellets are dried,
sized, cooled and bagged as final product. In some cases, ROP-TSP is granu-
lated to form GTSP; however, less than 10% of the total GTSP consumed domes-
tically is produced by this method.14f
Material balance data--On the basis of data from the literature, the
following material balance for TSP was developed.!if
100
-------
Phosphate Rock
377 kg
56.5 kg P
Air Emission
0.097 kg P
Unloading.
Grinding.
Feeding
Wel Process Phosphoric Acid
839 kg (40% P205)
146.4 kg P
I-'
a
I-'
Note:
Dashed I ines are gas streams.
Sourcp:
Reference LO.
Figure 6-6.
Reactor
r--,---- --- - - - ---,
I I
I I
I I
r--J I
Dry(:r
------
~
.D
-0
:>
U
VI
Dust
Recovery
r
I
I
I
I
I
,. ---- -----1---1
I I
To Atmas.
0.034 kg P
t
I
-_-.J
Contaminated
Water
21 ~ 40 I/MT
"0
...!!
u
>..
u ..
t> ..
0:: QI
U
.... 0
QI ....
... CL.
o
~ £
Phosphorus Values per MT Product
Input P = 202.9 kg P
Output P = 200.7 kg P
Atm Losses = 0.35 1..9 P
Water Losses = 0.00002 kg P
Aim. Emission
0.22 kg P
Intermittent Wastewater
Discharge. 0.00002 kg P
on Annual Basis
Product (46 % P20S)
1 MT
200.7 kg P
Flow diagram for production of granulated triple superphosphate.
-------
Raw material
Kilogram
Product
Kilogram
Phosphate rock (34% P205)
420 l
815 \
GTSP (46% P205)
1,000
Phosphoric acid (40% P205)
The phosphate rock contains 14.84% phosphorus and the phosphoric acid contains
17.46% phosphorus. The amount of phosphorus contained in the phosphate rock
is 62.3 kg, and the phosphorus present in the phosphoric acid is 142 kg. The
product TSP contains 200.7 kg phosphorus.
A phosphorus mass balance showing values which apply for 1 MT of
granulated triple superphosphate product follows:
Inputs
Phosphate rock
Phosphoric acid
56.5 kg P } .' 02 9
146.4 kg P Total 1nput 2 . kg P
Outputs
Product GTSP
Wastewater discharge
Atmospheric losses from
unloading, grinding,
and feed Prock
Atmospheric losses from
scrubber
Atmospheric losses from
bagging
200.7 kg P
0.00002 kg P
0.097 kg P
0.034 kg P
Total atm.
losses,
0.35 kg P
Total
accounted
for P losses,
0.351 kg
0.22 kg P
Unaccounted for P
1.85 kg P
Wastewater effluent--The data in Table 6-7
domestic TSP plants discharged any wastewater to the
data also indicate that all discharging plants treat
water with lime to reduce the phosphorus level.
show that only 10% of the
environment in 1977. These
the contaminated waste-
The data in Figure 6-6 show that the input of contaminated water to
a holding pond ranges from 21 to 40 liters/MT product. The EPA effluent limi-
tations guidelines for best practicable control technology currently available
(BPCTCA) specify that the maximum average concentration in this wastewater,
when discharged, shall be 35 mg phosphorus per liter~ It was assumed that
due to adverse weather conditions, 10% of the plants (see Table 6-7) discharged
treated effluent at 35 mg phosphorus per liter for a total of 2.5 months each
102
-------
L---
year at a discharge rate of 30 liters/MT
mated amount of phosphorus in discharged
per metric ton product.
product. On an annual basis, the esti-
wastewater is 0.00002 kg phosphorus
Atmospheric emissions--In the GTSP manufacturing process the operat-
ing areas contributing to losses of phosphorus to the atmosphere include par-
ticulate emissions from rock unloading, pulverizing and feedinf' reaction/
granulation, drying/cooling, grinding/screening, and bagging.1-1 These par-
ticulates are phosphate rock or.fertilizer.
The atmospheric emissions of phosphorus from the processes are esti-
mated on the basis of data reported in the literature.S.14/ The estimation
procedure is similar to that described on page 98. The results are shown in
Table 6-6. The estimated total air emissions are 0.3S kg of total phosphorus
per metric ton product.
The ROP-TSP process--A flow diagram representative of this process is
presented in Figure 6-7. The method is very similar to the NSP process with
the exception that phosphoric acid rather than sulfuric acid is used as the
acidulating medium. The mixing of acid (46 to S4% P20S) and rock is normally
conducted in a cone mixer. After discharge from the mixer, the slurry quickly
(lS to 30 sec) becomes plastic. Solidification, with evolution of gas, occurs
on a slowly moving conveyor (den) enroute to a curing area, where the product
remains for 2 to 4 weeks. Following curing, the ROP-TSP material is sized and
shipped in bulk.
Material balance data--The estimated raw material and product quan-
tities are as follows:16/
Raw materials Kilogram Product Kilogram
Phosphate rock (34% P20S) 420 ~ ROP-TSP 1,000
(46% P20S)
6S2 ~
Phosphoric acid (SO% P20S)
The quantity of phosphorus present in the phosphate rock
and the quantity of phosphorus in the phosphoric acid is 142.3 kg.
(ROP-TSP) contains 200.7 kg phosphorus.
is 62.3 kg
The produc t
A phosphorus mass balance showing values which apply for 1 MT of
product (ROPOTSP) follows:
103
-------
TABLE 6-b.
SOURCES AND ESTIMATES OF PIIOSPHORUS-CONTATNING AIR EHISSIONS
~'OR TRIPLE SUPERPHOSPHATE PRODUCTION
Uncan t ro II cd Controll cd
particulate emission factor Tota 1
emission (g of particulate P20S in Estimated level P emission
factor per 1 ~rr PZOS in emissions of emission after controls
produc.tion 3ctivity ( kg hIT product) product) (%) control ('/,) (kg p/Mr product)
GTSP PeOCCbS
Rock unloading NA 0.09 34 NA 0.006
Rock grinding 3 NA 34 80 0.090
Rock feediug NA 0.017 34 NA 0.001
Reactor, granu13tor, NA 0.05 46 NA 0.0045
dryer, cooler, screens
Cooling building NA 0.1 U 46 NA 0.009
Product grinding 0.25 NA ~I 80 0.02
I-' Product bagging n.s ~/ NA 0.22
0 NA
+:-
Tota 1 0.35
ROP-TSf' process
Rock un,oading NA 0.07 34 NA 0.005
Rock grinding :J NA 34 80 0.090
Rock fceding NA 0.014 34 NA 0.001
Cone mi.xer, den, curing NA 0.16 46 NA 0.015
building
TOla 1 O.ll
Sources:
Hetcrences 5 and 14.
~/
Emission factor includes % PZOS'
.21
~"ission factor after control.
NA = Not available.
-------
Wet Process Phosphoric Acid \SO,)~ P20S)
652 kg. 142.3 kg P
Unloading.
Gri ndi ng .
Feeding
Atm. Emission
0.096 kg P
Cone Mixer
----
Scrubber
))
.....
a
V1
Phosphate Rock
(34 % P205)
420 kg
62.3 kg P
Gos Containment
Enclosure
Phosphorus Values per MT Product
Inpul P = 204.6 kg P
Output P = 200.7 kg P
Aim Losses = O. II kg P
Water umes = 0.0007 kg P
940.....10501/MT
To Almas.
0.015 kg P
!
I
I
I
-c
II>
(;
;)
u ~
~ 0
.- ;)
U 0-
~~
-><
u
2
VI
~
II>
(; Intermittent
:3: ::: Wastewater
II> II>
U g Discharge
1;' a': 0 . 0007 kg P
~ 2 On Annual Basis
Contaminated Water
940 - 1050 I/MT
ROP - TSP to Curing
Nore'
Oashed lillt.:~j drc ba~ 5trt~Wns.
Source:
Retcrcncc III.
Product (46 % P20S)
1 MT
200.7 kg P
Figure 6-7.
Flow diagram for production of run-of-pile triple superphosphate.
-------
Inputs
Phosphate rock
Phosphoric acid
62.3 kg P }
142.3 kg P
Total input, 204.6 kg P
Outputs
Product, ROP-TSP
Wastewater discharge
Atmospheric losses from
unloading, grinding, and
feeding of Prock
Atmospheric losses from
scrubber vent
200.7 kg P
0.0007 kg P
0.096 kg P ~
0.015 kg P .~.
Total atm.
losses, 0.111 kg P
Total P
losses,
0.1117 kg
Unaccounted for P
3.79 kg P
Wastewater effluent--The wastewater treatment and management proce-
dure is identical to that discussed for the GTSP process. The input of contami-
nated water to the holding pond ranges from 940 to 1,050 1iters/MT product;10/
an average rate of 1,000 liters/MT product was assumed. This leads to an annual
phosphorus release in wastewater of 0.0007 kg phosphorus per metric ton prod-
uct.
Atmospheric emissions--The emission sources and waste components are
similar to those described for the NSP plant. The emissions of particulates
and fluoride vapors from the cone mixer, conveyor chamber, and curing building
are controlled by wet scrubbers using recirculated pond water. Particulate
emissions from rock grinding, storage, and transfer facilities are controlled
by baghouse filters.14/
The air emissions of phosphorus from the ROP process were estimated
on the basis of published information~/ The estimation procedure was identi-
cal to that described on page 98 and the results are summarized in Table 6-6.
The estimated total air emissions are 0.11 kg phosphorus per metric ton of TSP
product.
National emission for TSP production--For TSP 60% of total production
is by the GTSP process while 40% is by the ROP process.14/ About 10% of the
domestic producers discharge wastewater (treated) to the environment (see Table
6-7).11/ Using the appropriate 1978 production data and emission data shown in
Table 6-17, the annual total quantity of phosphorus released in wastewater is
approximately 0.5 MT. For air emissions, the annual total quantity is about
334 MT phosphorus for the GTSP process and70MT for the ROP-TSP process.
106
-------
Production of Ammonium Phosphates (SIC No. 2874)--
Ammonium phosphates are normally prepared by the neutralization of ortho-
phosphoric acid with ammonia. The product obtained depends on the ratio of
phosphoric acid and ammonia used, and may be monoammonium phosphate (NH4H2P04)
(MAP), diammonium phosphate [(NH4) HP04] (DAP), or a mixture of the two. Al-
though these products can be made !rom either furnace or wet-process acid, all
products currently intended for fertilizer use are based on wet-process acid.
A representative flow diagram for production of DAP is presented in Fig-
ure 6-8. The processing method and phosphorus releases for MAP, the other ma-
jor product of this type, are very similar. Thus, the data developed for phos-
phorus emissions apply generally for all ammonium phosphate processes.
Material balance data--For purposes of calculation, a DAP production com-
position of 18-46-0 (18% N, 46% P205' 0% K20), a common commercial grade was
used.
The production of 907 kg (1 short ton) of
of P205 in the form of phosphoric acid.1l1 The
(45% P205) required is 930.2 kg and the amount
On the basis of the production of 1 MT of DAP,
required is 1,026 kg. The phosphorus contained
201.5 kg.
this product requires 418.6 kg
quantity of phosphoric acid
of ammonia required is 197.7 kg.
the quantity of phosphoric acid
in this quantity of acid is
A phosphorus mass balance showing values which apply for 1 MT of product
ammonium phosphate is as follows:
Input
Phosphodc acid
201.5 kg P
Output
Produc t
Total wastewater discharge
Total atmospheric losses
200.7 kg P
0.002 kg P }
0.15 kg P
Total P losses, 0.152 kg
Unaccounted for P
0.648 P
Wastewater effluent--The allowable phosphorus concentration in wastewater
discharged to environment from this process according to the EPA effluent limita-
tions guidelines for best practicable control technology currently available
(BPCTCA) is a maximum average disch7rge for 10 or more consecutive days of 3S
mg of total phosphorus per liter.lQ This value was used to estimate the total
phosphorus discharge in effluent from ammonium phosphate plants.
107
-------
Phosphorus Values per MT Product
Input P = 201.5 kg P
Output P = 200.7 kg P
Atm Losses = O. 15 kg P
Water Losses = 0.002 kg P
Phosphoric Acid
(45°/" P:P 5)
1 026 kg
201 .5 kg P
.....
a
ex:>
Ammonia
Other Mat'ls
(Optiona I)
Source:
Scrubber
Water Vapor
Preneutra Ii zer
Ammoniator
Granu lator
Reference 10.
Figure 6-8.
Recycle
H20
Gas Discharge
Scrubber
Wastewater
Holding Pond
&
Treatment Unit
Gas
I nte rm i tte nt W astewate r
Discharge, 0.002kg P
on Annual Basis
Exhaust
Gas
Cyclone
Gas
Oversize
I
Dryer ~
I
Recyc Ie Fines
Fi nes
Flow diagram for production of ammonium phosphate.
Bagging
&
Shipping
Product.
1 MT
200.7 kg P
Total Atm
Discharge-
All Sources
O. 15 kg P
-------
10/ .
Data-- show that the discharge of contaminated water from the scrub-
ber to the holding pond ranges from 0 to 300 liters/MT of product for MAP to
5,000 to 6,500 liters/MT of product DAP.10/ It was assumed that during periods
of wastewater discharge to the environment (2.5 months/year) that the average
effluent discharge rate is 3,000 liters/MT.
Data on wastewater discharge practices are presented in Table 6-7. About
9% of all ammonium phosphate plants discharge wastewater. The estimated total
phosphorus discharge on an annual basis is 0.002 kg phosphorus per metric ton
of ammonium phosphate product.
Atmospheric emissions--The production activities, which are sources of
atmospheric emissions of phosphorus, include the ammoniator-granulator step,
product drying and cooling, material handling and product sizing and bagging.
The characteristics of these emission streams are very similar to those which
apply for NSP production.
Basic data for the estimation of the phosphorus losses to the atmosphere
during production of DAP were obtained from the literature.ll/ The results of
the estimates on atmospheric emissions for DAP production are shown in Table
6-8. The estimated total emission of phosphorus was 0.15 kg phosphorus per
metric ton of ammonium phosphate product.
National emission for ammonium phosphate production--The estimated produc-
tion rate in 1978 is 3,550,000 MT of P 05 (Table 6-17). Assuming the average
P205 content in these products is 46% tas in a typical DAP product), the esti-
mated total production rate is 7,717,400 MT of ammonium phosphate.
The unit emission factor for wastewater is 0.002 kg phosphorus per metric
ton product (Table 6-17). The approximate discharge of contained phosphorus in
this effluent is calculated to be 15 MT phosphorus.
Using the air emission factor, shown in Table 6-17, the annual phosphorus
discharge to the atmosphere is estimated to be 1,150 MT phosphorus.
Defluorinated Phosphate Rock Production (SIC No. 2048)--
This product is consumed principally in
supplements. Three general methods have been
to defluorinate phosphate rock.~/
the preparation of animal feed
developed in the United States
1. Treatment of NSP at elevated temperatures to volatilize the residual
fluorine.
2. Treatment of a mixture
shaft furnace to volatilize the
phate mass.
of phosphate rock and silica in an oil-fired
fluorine and yield a fused tricalcium phos-
109
-------
TABLE 6-7. WATER EFFLUENT DISPOSAL AND CONTAINMENT PRACTICES FOR THE
PHOSPHATE FERTILI ZER INDUSTRY
Industry, percent of plants specified
Normal Triple Tota 1
Wet process Super- super- sllper- Ammonium phosphate
phosphoric phosphoric phosphate phosphate phosphate ferti lizer
Process water discharged? acid plants acid plants plants p In nt S plants industry
Yes
Intermittently or continuously 12 0 4 10 9 8
With treatment 8 0 4 10 9 7
Without treatment 4 0 0 0 0 1
No
Discharged to gypsum ponds 64 63 48 63 56 56
Facilities have emergency, 42 50 7 47 26 27
or continual treatment of
ponds
Facilities have no emergency 11 13 7 0 13 8
treatment capabilities
t-' Insufficient information 11 0 34 16 17 21
t-' Process water di scharged to 8 13 0 16 9 7
a
abandoned mining pit
Other (see scrubber liquor, 8 12 18 11 13 13
using cooling towers, recycle
effluents, or combination)
Ihsufficient information 8 12 30 0 13 16
Nwnber of plants contacted 29 8 49 22 33 141
Number of plants in industry (1976) 36 9 61 2) 48 177
Source: Reference 10.
-------
TABLE 6-8.
SOURCES AND ESTIMATES OF PHOSPHORUS-CONTAINING AIR EMISSIONS
FOR DIAMMONIUM PHOSPHATE PRODUCTION
Production activity
Controlled
emission factor
(g of particulate
per 1 MT P205 in
product)
% P205
in
P emi ssions
after controls
(kg P/MT product)
emissions
Ammoniator-granulator
0.76
46
0.031
Dryer/cooler
0.75
46
0.030
Material transfer, product
sizing and bagging:
A. Controlled emission
B. Uncontrolled emis-
sion (fugitive
dust losses)
0.03
2.2
46
46
0.001
0.087
Total
0.149
Source:
Reference 14.
3.
Calcination of phosphate rock without fusion.
The third method, which has become the prominent domestic defluorination
process, is discussed in this subsection. A representative flow diagram for
this process is presented in Figure 6-9. The process basically involves the
reaction of phosphate rock with phosphoric acid and def1uorinating agents,
followed by agglomeration and def1uorination of the reaction mixture. The equa-
tion ~ePfsjentative of the chemical reaction and fluorine release in the pro-
cess 1.s:-
Ca10F2(P04)6 + H20 + Si02
) 3Ca3 (PO 4)2 + CaSi02 + 2HF 1
The reader is referred to Reference 15 for a detailed discussion of this
process.
Material balance data--This type of information was not found in the
technical literature or obtained by contacts with industry representatives.
Assuming the products contain 76.5% trica1ciUm phosphate (35% P205)' each
metric ton of def1uorinated phosphate rock contains 153 kg of phosphorus.
111
-------
Phosphate
Rock
Phosphori c 45 - 54 %
Acid P205
Other Defluorinating
Reagents
......
......
N
Silica Sand & Soda Acid
Non - Agglomerated
Feed
Fluidizing Gas
Heater
Effluent Gas
-----
Fluid
Bed
Reactor
Scrubber
Cyclone
Contami nated
Water
Dust
Recycle
Agglomerated and
Defl uori nated
Phosphate Product
1 MT
153 kg P
Phosphorus Values per MT
Input P = Unknown
Output P = 153 kg P
Atm Losses = 1.3 kg P
Water Losses = 0.33 kg P
Product
Source:
Reference 18.
Discharged
Wastewater
0.33 kg P
To Atmosphere
1. 3 kg P
Contami nated
Water
45,894 I/MT
27.5 kg P
Retention Pond
and Wastewater
Treatment Unit
Figure 6-9.
Flow diagram for production of defluorinated phosphate rock.
I-
~
"
o
o
o
It')
~
~
-------
A phosphorus mass balance showing values which apply for 1 MT of de-
fluorinated phosphate rock product is as follows:
Input P
155.53 kg (estimated)
Outputs
Product
Total wastewater losses
Atmospheric losses
from scrubber
Atmospheric losses
from material
handling
153 kg P
0.33 kg P
1.3 kg P
t
~
Total atm.
losses,
2.2 kg P
l
~
Total losses,
2.53 kg P
0.9 kg P
Wastewater effluent-- Since the process involves many trade secrets, only
a minimal amount of informa7ion is reported on wastewater characterization in
the published 1iterature.~ The types of wastewater involved are contaminated 18/
process water from stack-gas scrubbing and cleanup water from spills and 1eaks.---
The largest individual wastewater source is from water used in scrubbing
contaminants from the effluent gas streams.~/ Most plants operate on a complete
water recycle basis using a retention pond with make-up water added as required.
Wastewater accumulations require treatment and discharge only during periods of
excessive rainfall.
Because lime is added to the recirculating
calcium phosphate, calcium sulfate, and calcium
waste. The typical total us,ge of process water
45,900 1iters/MT product.li
wastewater to control the
fluoride precipitate as a
is reported to be about
pH,
solid
There are various sources of contaminated nonprocess wastewater. These
sources involve accidental spills, accidental leaks due to process equipment
failure and discharges from safety showers and personal safety equipment.
Many manufacturers have demonstrated that spurious contaminations from leaks
and spills and other sources can be held to a very low level.~/
The EPA effluent limitations guidelines (BPCTCA) for processes which de-
fluorinate phosphate rock recammend that the maximum average daily discharge
concentration (for 30 consecutive days) of total phosphorus should not exceed
35 mg phosphorus per liter of wastewater.1BV It was assumed that this value
would be the actual discharge concentration, that the plants would discharge
wastewater for only 2.5 months each calendar year, and that the discharge rate
would be the process water rate, or 45,900 liters/MT product. Thus, the estimated
annual phosphorus discharge is 0.33 kg phosphorus per metric ton product.
113
-------
1---
Atmospheric emissions--Air emissions of phosphate rock occur in handling
of the raw material. Also, emissions of defluorinated phosphate rock occur in
the atmospheric vent from the scrubber used to treat off-ga?es from ,he reac-
tor. These emissions were estimated on the basis of literature datal and are
discussed as follows.
Material hand1ing--The total material handling is reported to have
an uncontrolled particulate emission factor of 2 kg P ° per metric ton of
product and it is assumed there is no emission controt.~ Then, the estimated
emission is approximately 0.9 kg phosphorus per metric ton of def1uorinated
phosphate rock.
Drying-agglomeration--From data on drying/cooling of calcium phos-
phate,2I it was assumed that the uncontrolled particulate emission is 30 kg
P205 per metric ton of product and that the level of emission control is 90%.
The estimated emission is 1.3 kg phosphorus per metric ton product. The total
estimated air emissions from both sources is 2.2 kg phosphorus per metric ton
of defluorinated phosphate rock.
National emission for def1uorinated phosphate rock production--Domestic
production of this material in 1978 was about 272,000 MT. As shown later in
Table 6-17, the calculated wastewater emission factor is 0.33 kg/MT and the
air emission factor is 2.2 kg phosphorus per metric ton. The annual phosphorus
discharge in plant effluent is calculated to be approximately 90 MT phosphorus.
And the total air emission is estimated to be 600 MT phosphorus.
Production of Animal-Feed Calcium Phosphate (SIC No. 2819)--
Calcium phosphates are produced for use as a livestock feed-supplement
by the neutralization of defluorinated phosphoric acid with lime. The product
is usually a mixture of monocalcium phosphate, dicalcium phosphate (the prin-
cipal component), and trica1cium phosphate. A representative process diagram
is shown in Figure 6-10. For a detailed description af the process, the reader
is referred to Reference 19.
Wastewater effluent--The acid defluorination step consists of treating
heated phosphoric acid with finely-divided silica followed by aeration to
liberate silicon tetrafluoride gas. Wet-scrubbers hydrolyze and collect this
gas as f1uosilicic acid and silicic acid. The raw wastewater generated in
this treatment step does not contain a significant amount of phosphorus.19/
In the wet-scrubber used to treat off-gases from the pug mill reactor,
the estimated raw waste load in the effluent is 4 kg of dissolved PO per
metric ton of product.l2! The estimated total phosphorus load in raw4waste-
water.is 0.65 kg phosphorus per metric ton product animal-feed.
114
-------
Air
Silica
Lime
Phosphoric Acid
Pug Mill
Reactor
Water
Water
Atm. Vent 0.65 kg P
Vent
....
....
Ln
Waste
Nil P
Waste Effluent
0.65 kg P
I
Waste
Treatment
Total Phosphorus Loss per MT
Atm Losses = 2. 6 kg P
Water Losses = 0.026 kg P
Product
Source:
Reference 19.
Cyclone
Water
Product
Cooler
Product
1 MT
Rotary
Dryer
Discharged
Wastewater
0.026 kg P
Figure 6-10.
Flow diagram for production of animal-feed calcium phosphate.
-------
The estimated amount of process water discharged is 6,720 1iters/MT
product for the combined operation of acid def1uorination and solid scrubbing.
On the basis of EPA effluent limitation guidelines (BPCTCA), it is assumed
that the maximum discharge of total phosphorus in wastewater is 0.026 kg/MT
product anima1-feed.20/ This value is the same as that for food-grade calcium
phosphates.
Atmospheric emissions--These emissions are estimated on the basis of data
from the 1iterature.2I Air emissions occur from the vents on the reactor-scrubber
and from the scrubber used for drying and cooling operations. For each scrubber,
the uncontrolled particulate emission is estimated to be 30 kg P20S per metric
ton product, and the level of emission control is 90%. From these figures,
1.3 kg phosphorus per metric ton product is discharged from each scrubber; thus,
the total air emission is 2.6 kg phosphorus per metric ton of product anima1-
feed.
Summary of phosphorus losses to environment--The following data are for
phosphorus discharges to the environment which apply for 1 MT of animal-feed
calcium phosphate.
Total wastewater losses
0.026 kg P
Total atmospheric losses
2.6 kg P
National emission for production of anima1-feed-grade calcium phosphates--
Based on the estimated production rate and emission factors for 1978, the phos-
phorus discharges are calculated to be 17 MT of phosphorus due to wastewater
discharge and 1,651 MT of phosphorus from air emissions.
Production of Elemental Phosphorus (SIC No. 2819)--
Phosphorus is produced by the electric-furnace method, as shown in the
representative process f10wsheet in Figure 6-11. The raw materials are phos-
phate rock, silica, and coke. The simplified reaction is:
2Ca3(P04)2 + 6 Si02 + 10 C
> P4 + 6 CaSi03 + 10 GO
d" .1. h 1. 11.19/
The production technology is described in eta~ ~n t e ~terature.
Material balance data--The quantity of total phosphate rock used depends
on the analysis of the material. For 1 MT of phosphorus product, a typical grade
of phosphate rock used as feed contains 2,600 kg of P205 .~/ This value is
equivalent to 1,135 kg phosphorus. Assuming a P20S concentration of 26%, the
quantity of phosphate rock required is about 10,000 MT.l2/
116
-------
Phosphate
Rock
""10 MT
1 . 135 MT of
Contained P
Washed
Ores
Source:
Burn Excess CO
0.4 kg P
Atm Loss
Air Emission
O. 11 kg P
Ore
Blender
Atm. Vent
Water O. 15 kg P
Scrubber
Waste
0.7 kg P
Solid Wastes
0.85 kg P
Reference 19.
Coke
Storage
Air
Emission
0.11 kg P
"" 1. 5 MT
Air Emission
0.02 kg P
Sizing and
Calcining Kiln
Water
Precipitator
Slag
Quenching
Waste
O. 3 kg P
Water
Treatment
System
Discharged
Effluent
O. 15 kg P
Figure 6-11.
Si licci
Storage
"" 1.5 MT
Electric
Furnace
0.3 MT of
Ferrophosphorus
for Sale
66 kg P
p, CO, Dust
2.8 MT of CO
0.4 kg P
CO
Electrostati c
Precipitator
Phosphorus
Condenser
Dust
27.4 kg P
Recycled to
Process
Further Slag
Preparation
Before Sale
8.9 MT of Slag
23. 96 kg P
Sludge
Processing
Phosphorus Values per MT Product
Input P = 1135 kg P
Output P = 1000 kg P
Atm Losses = O. 64 kg P
Water Losses = O. 15 kg P
Flow diagram for production of elemental phosphorus.
1 MT P to
Storage
Phosphorus
Storage
Waste
16 kg P
to Water
Treatment
System
-------
For 1 MT of phosphorus product, a typical material balance shows the
quantity of by-products to be: ferrophosphorus (Fe2P)' 0.3lijJ; slag, 8.9 MT;
and carbon monoxide, 2.8 MT. On the basis of reported data,--- it was assumed
that the ferrophosphorus contained 22% phosphorus, the slag contained 0.27%
phosphorus, and the precipitator dust contained 21.9% phosphorus.
A phosphorus material balance was developed for the process flow diagram
presented in Figure 6-11 and as follows (basis 1 MT phosphorus product):
Inputs
Phosphate rock
Outputs
Product
Phossy water
Slag quenching water
Ca1cinor scrubber liquid
Handling losses to
atmosphere
Nodu1izing losses to
atmosphere
Furnace losses to atmosphere
Flare losses to atmosphere
Recycled electrostatic
precipitator dust
Ferrophosphorus
Slag (estimated by dif-
ference
Total output
Kilograms of
total phosphorus
1, 135
1,000
16 }
0.3
0.7
0.11
Total water ef-
fluent, 17 kg P; dis-
charged effluent, 0.15 kg P
Total P
losses to
environ-
ment,
0.11
Total atmospheric
losses, 0.64 kg p
0.79 kg
0.02
0.4
27.4
66 }
Total in by-products, 89.98 kg P
23.96
1,135
Effluent wastewater--The phosphorus production industry is characterized
by large amounts of raw process wastes, including scrubber and slag quenching
wastewaters which contain substantial quantities of fluids, dissolved solids,
and suspended solids.l2J Some plants have demonstrated control- practices giving
97% or greater reduction in the raw waste load before discharge to the environ-
men t .12./
In this study it was assumed that all phosphorus production plants treat
the wastewater so as to meet the discharge standards of the best practicable
control technology currently available. The discharge standard specifies that
the average of daily values for 30 consecutive days shall not exceed 0.15 kg
118
-------
20/
total phosphorus per metric ton product.-- It was assumed that the plants
operate with this maximum allowable discharge of phosphorus in effluent.
Air emission1/_-The phosphate rock feed must be processed through a cal-
cining kiln operation before the rock can be used as a furnace charge. Air
emissions of rock dust are involved in the handling and calcining operations.
The calcining step is a significant generator of P20S emissions and scrubbers
are often employed to reduce particulate emissions.
There are some general sources of P Os emissions in the operation of the
electric furnace. Fumes of P20 tend to teak out of the furnace around the elec-
trodes and the feed bins. Anot~er emission source is the furnace tapping opera-
tion. Since visible quantities of P20 fumes can result during tapping of slag
and ferrophosphorus, many operations ~ave installed hood and ventilation sys-
tems designed to capture the fumes and direct them through gas scrubbers.
Other P20 emissions are from the handling of collected dusts from air
pollution cont~ol devices and from the storage and transfer of phosphorus.
Since these operations are infrequent and the quantities handled are small,
the total emissions from the sources are estimated to be negligible.
The burning of excess carbon monoxide in a flare results in air pollution
by phosphorus pentoxide (P20S).
Estimates of the phosphorus emissions to the atmosphere were performed
according to the procedures described previously on page 98. Results of these
estimates are summarized in Table 6-9. The estimated total phosphorus discharge
to the atmosphere is 0.64 kg/MT product.
National emission for elemental phosphorus production--The estimated pro-
duction rate for elemental phosphorus in 1978 is 462,000 MT (see Table 6-17).
The approximate
69 MT phosphorus and
phosphorus.
discharge of phosphorus in wastewater is estimated to be
the air emissions are estimated to be approximately 296 MT
Production of Phosphoric Acid by the Dry Process (SIC No. 2819)--
A typical flowsheet is presented in Figure 6-12. Elemental phosphorus is
converted to orthophosphoric acid (H3P04) by the following overall reaction.
P 4 + SO 2 + 6 H2 °
) 4H3P04
Phosphorus is often converted to phosphoric acid at
original point of production. De]ailed descriptions
sented in the literature.S.ll.19
locations other than the
of this process are pre-
119
-------
TABLE 6-9.
SOURCES AND ESTIMATES OF PHOSPHORUS-CONTAINING AIR EMISSIONS
FOR PRODUCTION OF ELEMENTAL PHOSPHORUS
Uncontrolled Estimated
particulate level of
emission % P205 emission P emissions
factor in control after controls
Production activity (kg/Mr) emissions (%) (kg p/Mr product)
Phosphate rock handling 1 25 0 0.11
Calcining kiln (nodulizing) 0.65 ~/ 60 0.11
Furnace operations 0.5 ~I 90 0.02
Flares 0.9 ~/ 0 0.40
Total 0.64
~I
Emission factor includes % PZ05.
Source:
Reference 3.
120
-------
I-'
N
I-'
Liquid
Phosphorus
273.7 kg P
Source:
Air
Combustion
Furnace
Reference 19.
Figure 6-12.
Atm. Vent
0.57 kg P
Dust Waste
2.86 kg P
Electrostatic
Precipitation
Water
NaSH
P205
Hydration
Purification
Phosphorus Values per MT Product
Input P = 273.7 kg P
Output P = 270 kg P
Atm Losses = 0.57 kg P
Water Losses = O~ 044 kg P
Water
Fi Itration
85%
Phosphoric
Acid Product
1 MT
270 kg P
Waste
Note:
Estimated Total Phosphorus Release to Environment as
Treated Wastewater from Cle"anup of Leaks and Spills
is O. 044 kg
Flow diagram for production of phosphoric acid (dry process).
-------
1__-
Material balance data--In a typical process, the production of 1 MT of
product.s:!Cfid containing 85% H3P04 requires 273.7 kg of phosphorus as raw ma-
. 1 J.1J
terJ.a .
A phosphorus mass balance showing values which apply for 1 MT of phos-
phoric acid follows:
Input
Phosphorus
273.7 kg P
Outputs
Product
Total wastewater discharge
Total atmospheric losses
Dust waste (recycled)
Unaccounted for P
270 kg P
0.044 kg P }
0.57 kg P
2.86 kg P
0.226 kg P
Total accounted for P
losses, 0.614 kg
Wastewater eff1uent--No aqueous waste streams are generated in this pro-
cess.
In spite of good housekeeping practices, losses of phosphoric acid (H3P04)
. by leaks and spills can amount to an average of 1 kg of H3P04 per metric ton of
product.l2I The estimated phosphorus is 0.27 kg phosphorus per metric ton prod-
uct.
It was assumed that plant cleanup wastewater containing this phosphorus
is treated in pollution control equipment and then discharged to the environ-
ment. On the basis of the EPA effluent limitation guidelines (BPCTCA), the es-
timated phosphorous loss to the environment in wastewater is 0.044 kg total
phosphorus per metric ton product.20f
Atmospheric emissions--Phosphoric acid mist is a pollutant in the tail
gas vented from the hydration and electrostatic precipitation steps. Although
all plants are equipped with some type of acid mist collection systems, some
mist does escape to the atmosphere.
An estimate of the phosphorus emissions as H3P04 mist to the atmosphere
from this process was made on the basis of literature data.if For the hydra-
tion step, the estimated particulate emission factor after controls is 1.3 kg
P205 per metric ton product or 0.57 kg phosphorus per metric ton product.
Solid waste--Most of the phosphorus in the off-gases from the hydration
step is recovered in the electrostatic precipitator and is contained in the
dust waste.
122
-------
It is assumed that the phosphorus output not accounted for in the finished
product, vented mist, and leaks and spills occurs in the dust from the electro-
static precipitator. On this basis the contained phosphorus in this dust is
2.86 kg phosphorus per metric ton product. It was assumed that this dust is
recycled to the process.
National emissions for dry process phosphoric acid production--For 1978,
the estimated total domestic production of dry process phosphoric acid is equiv-
alent to 833,000 MT of contained P205. Assuming an acid concentration of 61.87%
P20S (86% H3P04) the estimated proouction of dry process phosphoric acid is
1,346,400 MT.
The estimated total emission from wastewater discharge are 60 MT phosphorus;
about 770 MT of phosphorus are contained in the total annual air emissions.
Phosphorus Pentoxide Production (SIC No. 2819)--
The production of solid anhydrous phosphorus pentoxide involves burning
liquid phosphorus in an excess of air:
P 4 + 502
.> 2P 205
Figure 6-13 is a representative flow diagram for this process; details of the
operation are reported in Reference 19.
Material balance data--The process yield on raw material phosphorus was
assumed to be 98%.l2/
The phosphorus contained in 1,000 kg of product P205 is calculated to be
436.4 kg.
The phosphorus raw material required is estimated to be 445 kg.
A phosphorus mass balance showing values which apply for 1 MT of phos-
phorus pentoxide product follows:
Input
Phosphorus
445 kg P
Outputs
Product
Total wastewater losses
Total atmospheric losses
Unaccounted for P
436.4 kg P ,
0.024 kg P }
8.5 kg P
0.076 kg P
Total accounted for
P losses, 8.524 kg
123
-------
Air
Removed Water
Liquid Phosphorus Storage
445 kg P
I-'
N
.p-
Phosphorus Values per MT Product
Input P = 445 kg P .
Output P = 436.4 kg P
Atm Losses = 8.5 kg P
Water Losses = 0.024 kg P
Source:
Reference 19.
Figure 6-13.
Discharged
Wastewater
o . 024 kg P
Combustion
Chamber
Waste
Treatment
Unit
Condensing
Tower
Effluent
0.08 kg P
Product
P205
1 MT
.436.4 kg P
Atm. Vent
8. 5 kg P
Flow diagram for production of phosphorus pentoxide.
-------
Wastewater effluent--The typical contaminated wastewater from the tail
seals for the condensing tower is reported to contain 0.25 kg of H3P04 (100%)
per metric ton product.12I On this basis, the quantity of phosphorus contained
in this waste stream is estimated to be 0.08 kg phosphorus per metric ton of
product.
It was assumed
that the discharged
lines which specify
that this waste is treated in a pollution control unit and
wastewater conforms to the BPCTCA effluent limitation guidj-
0.024 kg of contained phosphorus per metric ton product.~
Atmospheric emissions--The estimated phosphorus losses
spills, and leaks are calculated from a material balance to
per metric ton product.
due to handling,
be 8.5 kg phosphorus
National emission for phosphorus pentoxide production--Domestic produc-
tion of this compound in 1978 amounted to about 8,000 MT and the estimated
emission factors are 0.024 and 8.5 kg phosphorus per metric ton of product for
wastewater discharge and air emissions, respectively. The estimated total an-
nual phosphorus quantities in wastewater discharge are 0.2 MT and 68 MT in air
emissions.
Phosphorus Trichloride Production (SIC No. 2819)--
Phosphorus trichloride (PC13) is manufactured directly from the elements
according to the reaction.12I
P4 (liquid) + 6C12 (gas)
> 4PC13 (liquid)
A representative flow diagram for this process is given in Figure 6-14. Details
of process operations are described in References 12 and 19. Phosphorus tri-
chloride is used as a raw material in the production of phosphorus oxychloride
pesticide intermediates, phosphate esters, surfactants, and organic alkyl chlo-
rides.
Material balance data--Published information shows that a typical material
balance for the process is as follows:12
Raw materials
Kilogram
Product
Kilogram
Chlorine
238 l
815 f
PCl
1,000
Phosphorus
The phosphorus content of the pure product is 22.55%. Then, the amount of phos-
phorus in 1,000 kg of PC13 is 225.5 kg.
125
-------
Chlorine
Liquid
Phosphorus
Storage Tank
238 kg P
I
Batch
Reactor
t-'
N
C1\
Raw Waste
Phossy W ate r
0.24 kg P
Waste Residue
(Solid)
O. 02 kg P
Phosphorus Values per MT
Input P = 238 kg P
. Output P = 226 kg P
Atm Losses = 10.8 kg P
Water Losses = 0.05 kg P
Solid Residue = 0.02 kg P
Product
Source:
Reference 19.
Figure 6-14.
Flow diagram for production of phosphorus trichloride.
Reflux
Condenser
Holding
Tank
Transfer to
Containers
Condenser
Water
Water
Discharged
Wastewater
O. 05 kg P
Wastewater
Treatment
Effluent
O. 94 kg P
Note: Total Atmospheric Losses from Transfer and Storage
of P and PCI3 are 0.45 kg P/MT of Product PCI3
PCI3
Product
1 MT
226 kg P
Atm
Emission
10.4 kg P
-------
A phosphorus mass balance showing values which apply for I MT of phos-
phorus trichloride product follows:
Input
Phosphorus
238 kg P
Outputs
Product
Total wastewater losses
Total atmospheric losses
Total solid waste residue
Unaccounted for P
226 kg P
0.05 kg P I
10.8 kg P
0.02 kg P
1.13 kg P
Total
for P
10.87
accounted
losses,
kg
Wastewater effluent--Elemental phosphorus is transported and stored under
a water blanket to prevent combustion on exposure to air. Therefore, phossy
water is a raw waste material at plants using phosphorus. The standard raw
phossy water wastes are caused by surges or anomolies in the storage tank water
level control system rather than to the direct discharge of all displaced water.
This water contains colloidal phosphorus as well as phosphoric acid.!2! .
No direct process
phosphorus storage and
leaks and spills.!2/
aqueous wastes are generated. Raw wastes arise from
transfer, wet-scrubbing of gases, vessel cleaning, and
Some spill
operations. The
some PC13.
and leak losses (atmospheric) of PC13 occur during transfer
tail gases vented to atmosphere from the scrubbers also contain
The waterborne raw wastes contain
by hydrolysis of PC13 contained in the
from washing tank cars and tank trucks
H3P03' H3P04' and HCl,
waste. The acid wastes
are very small.
which are formed
(H3P03' H3P04)
The waterborne raw waste from the
is reported to contain 2.5 kg of H3P03
phosphorus content is calculated to be
uct.
scrubber for distillation tail gases
per metric ton product.19/ The estimated
0.94 kg phosphorus per metric ton prod-
For each metric ton of phosphorus consumed in the ~70duction process, 1 kg
of phosphorus is discharged in the phossy water waste.~ However, the produc-
tion of 1 MT of phosphorus trichloride requires only 0.238 MT of phosphorus
so that the total phosphorus discharged in the phossy water waste would be
0.238 kg/MT product. Combining this figure with 0.94 kg stated above gives a
total phosphorus content in wastewater of 1.18 kg phosphorus per metric ton
product.
127
-------
It is assumed that the wastewater is treated in some fashion with pollu-
tion control equipment so that the phosphorus contained in treated discharged
waste is 0.05 kg/MT of PC13 product. This value is specified in the EPA efflu-
ent limitation guidelines (BPCTCA).20/
Atmospheric emissions--The transfer and storage of phosphorus and phos-
phorus trichl~ride account for the equivalent loss of 2 kg of PC13 per metric
ton product..!.V Then, the corresponding emission of phosphorus is calculated
to be 0.45 kg phosphorus per metric ton product.
The amount of phosphorus discharged from scrubber vents is calculated,
by difference, from a process material balance to equal 10.36 kg/MT product.
Thus, the estimated total atmospheric phosphorus discharge is 10.8 kg/MT of
PC13.
Solid waste residue--Solid waste, which is removed periodically from the
reactor-still, reportedly contains 0.1 kg of pci3 per metric ton product.19/
The amount of phosphorus contained in this waste would be 0.02 kg phosphorus
per metric ton product. No information was obtained concerning the final dis-
posal of this solid waste.
National emission for phosphorus trichloride production--Application of
the 1978 production data and the emission factors listed in Table 6-17 results
in the following estimated plant discharges of phosphorus:
Wastewater:
5 MT phosphorus
Air emission:
1,002 MT phosphorus
Phosphorus Oxychloride Production (SIC No. 2819)--
Phosphorus oxychloride, which is utilized in the preparation of phar-
maceutical chemicals and organic phosphate esters, is produced commercially
by the reaction of liquid phosphorus trichloride, chlorine gas, and solid phos-
phorus pentoxide.19/
3PC13 + 3Cl2 + P205
:::> 5POCl3
A typical process flow diagram is given in Figure 6-15. Details of the process
operations are discussed in References 12 and 19. Phosphorus oxychloride is
used as a raw material in the production of tricresyl and triphenyl phosphates,
cyclic esters, and acyclic esters.
Material balance data--Data taken from Reference 12 show the following
representative material balance for this process:
128
-------
Phosphorus Values per MT Product
Input P = 206.9 kg P
Output P = 202 kg P
Atm Losses = 4.74 kg P
Water Losses = 0.05 kg P
540 kg PCI3
121. 8 kg P
To Atmosphere,
Total Vent
Emissions and
Spi lis
4.74 kg P
Water
Scrubber
Wastewater
O. 08 kg P
195 kg P205
85. 1 kg P
CI2
Batch Reactor
Water
Holding Tank
Transfer to
Containers
Wastewater
0.08 kg P
Waste
Treatment
Product
1 MT
202 kg P
Discharged
Wastewater
0.05 kg P
Source:
Reference 19.
Figure 6-15.
Flow diagram for production of phosphorus oxychloride.
129 .
-------
Phosphorus Phosphorus
Raw materials Kilogram content (kg) Product Kilogram content (kg)
PC13 540 121.8 j
C12 280 - POC13 1,000 202
P205 195 85.1
A phosphorus mass balance showing values which apply for 1 MT of phos-
phorus oxychloride product follows:
Inputs
Phosphorus pentoxide
Phosphorus trichloride
85.1 kg P }
121.8 kg P Total P input, 206.9 kg
Outputs
Product
Total wastewater losses
Total atmospheric losses
Unaccounted for P
202 kg P }
0.05 kg P
4.74 kg P
0.11 kg P
Total P losses, 4.79 kg
Phosphorus losses in the process occur in the effluent from the wet-
scrubber for the reactor-still and in the eflluent from the scrubber for off-
gases from product transfer to containers.li Also, small amounts of phosphorus
release occur in container cleaning operations. In the presence of the water
in these effluent wastes, PO~13 is hydrolyzed to form H3P04 and HCl.
Some plants filter the product; when this practice is followed, the used
filter elements are first washed to hydrolyze the residual POCI and the dis-
posable elements landfilled. The amount of solids retained on t~e filter ele-
ments is a very small fraction of the weight of the filter element. These ele-
ments are washed in a small drum so that only a small quantity of acid wastes
is involved compared to the scrubber waste 10ad.12/
A small amount
reactof4/Twice each
water.-
of residue (mostly glassy phosphates) accumulates in the
year this residue is washed out of the reactor with hot
Wastewater effluent--The water scrubber for product transfer to containers
reportedly collects about 0.15 kg of H3P04 per metric ton product.19/ It is
assumed that the wastes from returnable container cleaning operations (0.1 kg
H3P04) are discharged along with the scrubber wastewater for a total of 0.2 kg
H3P04 or a phosphorus discharge in the effluent of 0.08 kg phosphorus per metric
ton product.
130
-------
The water scrubber for the distillation operation typically collects
0.25 kg of H3PO~ (100%) per metric ton of product.l2! Then, the phosphorus
contained in th1s acid is 0.08 kg phosphorus per metric ton of product.
Thus, the estimated total phosphorus in wastewater effluent is 0.16 kg
phosphorus per metric ton product. This waste is processed in a waste treating
unit and the discharged phosphorus }n wastewater is 0.05 kg/MT which meets the
EPA effluent guidelines (BPCTCA).20
Atmospheric emissions--The total atmospheric loss
scrubber vents and spills is estimated, by difference,
to be 4.74 kg phosphorus per metric ton of product.
of phosphorus from
from the material balance
Solid wastes--The total solid wastes (glassy phosphates) are reported to
be less lhan 0.05 kg/MT product. The phosphorus content of these wastes is un-
~o~.~
National emission for phosphorus oxychloride production--The
phosphorus losses to environment based on production and emission
Table 6-17 are:
estimated
data in
Wastewater:
4 MT phosphorus and
Air emission:
376 MT phosphorus
Phosphorus Pentasulfide Production (SIC No. 2819)--
The standard commercial
as shown in the flow diagram
elements in liquid form:
process for production of phosphorus pentasulfide,
in Figure 6-16, is by the direct reaction of the
P4 + 10 S
;. 2P2S5
The product is used principally for the manufacture of lubricating oil addi-
tives and as a raw material in the organophosphorus pesticide industry.. A dis-
cussion of processing details is given in the technical literature.127 Phosphorus
pentasulfide is used in the production of lube oil additives, pesticides, and
flotation agents.
Material balance data--Input and output data for this process were obtained
from Reference 12.
Raw materials Kilogram
Phosphorus 295 ~
Sulfur 760 )
Product
Kilogram
Phosphorus
content (kg)
P2S5
1,000
278.7
131
-------
Note:
Total Air Emissions of
Phosphorus (Scrubber
Vent Plus leaks and
Spills) = 15.1 kg P
Sulfur
Storage
Tank
!-'
\..oJ
N
N2 Purge
Batch
Reactor
liquid
Phosphorus
Storage
Tank
295
kg P
Raw Waste
Phossy Water
0.3 kg P
To Waste
Treatment
Unit
Water
Seal
Source:
Seal Residue
to land Burial
O. 1 kg P
Reference 19.
P2SS
Holding
Tank
Vent
Phossy
Water
Atm.
Vent Water
Waste
Treatment
Raw .Wastewater
O. 16 kg P
To Waste
Treatment Unit
Casting
Crushing
Product, 1 MT
279 kg P
Cold Trap
Waste Residue
to land Burial
0.05 kg P
Heat
Exchanger
Vacuum
Pump
Phosphorus Values per MT Product
Input P = 295 kg P
Output P = 279 kg P
Atm Losses = 15.1 kg P
Water Losses = 0.039 kg P
Figure 6..16.
Flow diagram for production of phosphorus penta sulfide.
Discharged
Wastewater
0.039 kg P
Vent
Dust
Collector
Waste Dust
0.25 kg P
-------
1------
A phosphorus mass balance showing values which apply for 1 MT of phos-
phorus pentasulfide product follows.
Input
Phosphorus
295 kg P
Outputs.
Product
Total wastewater losses
Total atmospheric losses
Total solid wastes to landfill
Unaccounted for P
279 kg P
0.039 kg p
15.1 kg P
0.4 kg P
0.461 kg P
I Total P
\ losses,
15.539 kg
Wastewater effluent--In the casting of liquid P 2S" to form the solid
product, fumes from the burning liquid (auto-igniteJ) ~re treated in a wet-
scrubber. The waste water discharged from this scrubber contains phosphorus
in the form of H3P03 and H~P04 (0.5 kg of H3P03 and H P04/MT of product). The
amount of phosphorus in th1s waste can be estimated, ~ssuming all acid to be
H3P04' at 0.16 kg phosphorus per metric ton product.~/
Some phosphorus losses occur in the discharge of phossy water during the
material handling operations for liquid phosphorus. The phosphorus in this
wastewater is in the form of colloidal phosphorus as well as H PO and H P04.
The quantity of total phosphorus in discharged phossy water is3l ~g phos~horus
per metric ton of phosphorus consumed in the process.12/ On this basis, the
total discharged phosphorus in phossy water is approximately 0.3 kg phosphorus
per metric ton product. The estimated total phosphorus content in wastewater
is 0.46 kg phosphorus per metric ton product.
It was assumed
lution control unit
effluent guidelines
ton product.11.!
that the
and that
(BPCTCA )
combined wastewater streams are treated in a pol-
the discharged wastewater conforms to the EPA
so that 0.039 kg total phosphorus is lost per metric
Atmospheric emissions--Losses of phosphorus occur as P205
to the air from the vent on the wet-scrubber unit.12/0ther air
elude spills and leaks of phosphorus and of finished product.
fumes emitted
emissions in-
Solid wastes~-Water seals on the batch reactor vent lines accumulate a
mixture of lower phosphorus sulfides and phosphorus mud. This residue, which
is hazardous and flammable, is typically disposed of by land-burial. These
wastes contai? about 0.15 kg of unidentified solid compounds per metric ton
of product.~ Assuming these wastes to be 50% phosphorus mud, and 50% phos-
phorus sulfide, the total phosphorus content can be estimated at approximately
0.1 kg phosphorus per.metric ton product.
133
-------
The dust collected by a dry cyclone separator from the off-gas stream for
the'P2S5 crushing operation is a solid waste material; the quantity of this
dust amounts to about 1 kg/MT product.19/ Assuming that the dust contains 90%
P2S5' the estimated phosphorus content is calculated to be 0.25 kg phosphorus
per metric ton of product.
The still pot for the vacuum distillation step accumulates impurities in-
cluding carbon, iron phosphate, sulfur compounds, arsenic pentasulfide, and
glassy phosphates.19/ The entire still pot residue amounts to about 0.5 kg/MT
product. This pot residue is removed periodically and the solids broken up and
buried.l2! Assuming that the glassy phosphates comprise one-half of the total
waste and that the phosphates consist of FeP04' the estimated content of phos-
phorus is 0.05 kg phosphorus per metric ton product.
The estimated total phosphorus contained in solid wastes is 0.4 kg phos-
phorus per metric ton product.
National emission for phosphorus pentasulfide production--On the basis
of production rate and emission data, the estimated phosphorus discharges are:
Wastewater:
3 MT,
Air emissions:
1,160 MT, and
Solid wastes:
31 MT phosphorus.
Sodium Tripolvphosphate CSTPP) Production (SIC No. 2841)--
This product is manufactured by the neutralization of phosphoric acid
(normally furnace acid) by soda ash or by caustic soda and soda ash, with sub-
sequent calcination of the dried mono- and di-sodium phosphate crystals.12/
The standard manufacturing process is presented in Figure 6-17. Principal uses
for this product are in detergents and in water supplies as a means of con-
troiling corrosion. The product is also used in some softened waters for stabili-
zation of calcium carbonate to eliminate the need for recarbonization.1l!
Several plants of this type are reported to have no process wastes.12/
Collected dust from the spray dryer effluent stream is combined with the spray
dryer solid product stream. Water utilized for subsequent scrubbing of the gas
stream from the spray dryer is recycled to the mix area and used as process
water in the neutralization step. Cooling air used for tempering the product
is vented into the spray dryer vent line upstream of the scrubbing operation.
These pollution control techniques are generally applicable throughout the indus-
try. The effluent guideline standard (BPCTCA) is no discharge of wastewater.12/
Thus, it is concluded that no significant phosphorus releases to the environ-
ment occur from this process.
134
-------
Figure 6-17.
Phosphori c
Acid
Byproduct
C02
Source:
Gas
Dust Collector
Product Milling
and Sizing
~
Product
1 MT
I'Jote:
Negligible Amount of
Phosphorus in Process
Wastes or Byproduct
Reference 19.
Flow diagram for production of sodium tripolyphosphate.
135
-------
Production of Sodium Phosphates - SIC No. 2841 (Excluding STPP)--
These products are used principally for detergent manufacturing and water
treatment. Detergent industries generally require high purity sodium phosphates;
this purity standard has greatly limited the use of wet-process acid, which has
several impurities, as a phosphate source for this industry. Normally, phosphoric
acid manufactured by the furnace process is used because of its higher purity.
However, one company does purify wet-process acid to the extent necessary to
allow its use in the manufacture of sodium phosphate compounds for detergent
manufacture ..~/
As an example for this industry, this subsection will examine the produc-
tion of sodium phosphates from furnace phosphoric acid and sodium carbonate.
The process flow diagram is shown in Figure 6-18. The reader is referred to
Reference 12 for a detailed process description. The basic reactions are:
Na2C03 + H3P04
> Na2HP04 + C02'" + H20
:> Na3P04 + H20
Na2HP04 + NaOH
12/
Material balance data----- The quantities
trisodium phosphate, Na3P04.l2 H20 as follows:
of reactants are based on 1 MT
Kilo- Phosphorus Kilo- Phosphorus
grams content (kg) Produc t grams content (kg)
Phosphoric acid (45% P&05) 440 86.4 l TSP
Sodium carbonate (58% a20) 300 ~ ~ (Na3P04. 1,000 81.5
Sodium hydroxide (76% Na20) 120 12 H20)
A phosphorus mass balance showing values which apply for 1 MT of sodium
phosphate product is:
Input
Phosphoric acid
86.4 kg P
Outputs
Product
Total wastewater losses
Total atmospheric losses
Unaccounted for P
81.5 kg P
0.004 kg P }
2.0 kg P
2.896 kg P
Total P losses, 2.004 kg P
136
-------
Sodium
Carbonate
Solution
Wastewater
Stream A
. t-'
W
-..J
Source:
36 .'. k~ )
Phosphori c
Acid Carbon
Dioxide
Product,
Disodium
Phosph ate
(No Production
in This Example)
Reference 19.
Figure 6-18.
Sodium
Hydroxide
Solution
Batch
Vacuum
Crystallizer
Vacuum
Wastewater
Stream B
Double Effect
Evaporator
Collecting
Tank
Trap
Sodium Sulfate &
Sodium Carbonate
Phosphorus Values per MT Product
Input P = 86.4 kg P
Output P = 81.5 kg P
Atm Losses = 2.0 kg P
Water Losses = 0.004 kg P
Vacuum
Fi Iter
Product,
Trisodium
Phosphate
1 MT
81.5 kg P
Note:
Total Discharge nf Phosphorus
in Wastewater (Streams A + B)
Following Waste Treatment
is O. 004 kg
Flow diagram for production of sodium phosphates.
Atm.
Vent
2 . 0 kg P
-------
Wastewater effluent--The range of raw wastewater discharged by sodium
phosphate plants varies from 7,640 to 10,013 liters/MT product.~ Since a
typical effluent contains about 250 mg of total phosphorus per liter, the total
phosphorus content of the raw wastewater ranges from 1.9 to 2.5 kg/MT product.
The EPA recommendation of effluent llinitation guidelines (BPCTCA) for the
sodium phosphates subcategory show that the maximum phosphorus discharge should
not exce28Jan average of 0.004 kg of total phosphorus for each metric ton of
product. It is assumed that the treated wastewater discharged to the environ-
ment contains this amount of phosphorus.
Atmospheric emissions-~The process operations of product drying, cooling,
grinding, and packaging are considered to be significant sources of air emis-
sions of product particulates.
Estimates of the phosphorus emissions to the atmosphere were based on
published data.~/ These estimates are according to methods described earlier
in this section (see page 98); the results are shown in Table 6-10. The esti-
mated total phosphorus discharge to the atmosphere is 2.0 kg phosphorus per
metric ton product.
TABLE 6-10.
SOURCES AND ESTIMATES OF PHOSPHORUS-CONTAINING AIR EMISSIONS
FOR SODIUM PHOSPHATES (EXCLUDING SODIUM TRIPOLY-
PHOSPHATE)
---..-..--
Uncont ro lled Estimated
particulate level of
emission % P20S emission P emissions
factor in control after controls
Production activity (kg/MT) emissions (%) (kg P/MT product)
Drying-cooling 30 ~I 90 1.3
Grinding 10 ~/ 97 0.1
Bagging O.S,!?.! ~/ E./ 0.2
Material handling 1 ~/ 0 0.4
-
Total 2.0
2./
Emission factor includes % P20S.
'8./
Emission factor after control.
Source:
Reference 5.
138
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National emission for production of sodium phosphates--For all other sodi-
um phosphate products except STPP, the estimated national production rate in
1978 is 353,000 MT (Table 6-17). The annual discharge of phosphorus can be esti-
mated at 1 MT for wastewater and 706 MT for air emissions.
Production of Food-Grade Calcium Phosphates (SIC No. 2819)--
These products are made by the neutralization of phosphoric acid (furnace
process) with lime.li/ Integrated plants producing all types of calcium phos-
phate products are common in the industry. The reactions are chemically similar;
however, the methods of manufacturing the various calcium phosphates differ sub-
stantially from one another in the amount and type of lime used and the quantity
of process water required. The standard flow diagram for these products is shown
in Figure 6-19, and detailed information on these processes is presented in
References 11 and 19.
Monocalcium phosphate
in a stirred batch reactor
ing to the reaction: 19/ .
(MCP) production--A relatively pure MCP is prepared
from furnace phosphoric acid and lime slurry accord-
2H3P04 + Ca(OH)2
;> Ca(H2P04)20H20 + H20
An excess of phosphoric acid is maintained during the batch reaction cycle
to inhibit formation of dicalcium phosphate. A minimum amount of process water
is used.19/
Tricalcium phosphate (TCP) production--TCP is prepared in a manner similar
to that for MCP, except that an excess of lime slurry is maintained during the
batch reaction to inhibit formation of dicalcium phosphate.l2! The reaction
is:
2H3P04 + 3Ca(OH)2'
> Ca3(P04)2 + 6HZO
Dicalcium phosphate (DCP) production--This product is prepared using batch
reactors with much more process water than for MCP or TCP production.!2! The
reaction is:
H3P04 + Ca(OH)Z
"> CaHP04 .2H20
Wastewater effluent--The raw wastewater from production of food-grade cal-
cium phosphates is from two primary and approximately equal sources: filtrate
from dewatering of DCP slurry and effluent from wet-scrubbers, which collect
airborne solids from product drying operations. Both sources contain finely
divided, suspended particles of calcium phosphateso~/
139
-------
li me
Water
......
.p-
O
Excess H3P04
Hot Gas
Water
Vent
Source: Ref. 19
Excess Ume Slurry
Steam
Vent
Figure 6-19.
General flow diagram for production of food-grade calcium phosphates.
-------
In an integrated plant, the normal practice is to partially recycle the
scrubber water and to partially use the DCP filtrate as makeup scrubber water.
The total raw wastes from this system are typically 4,200 1iters/MT product;
these wastes contain 100 kg/MT of solids (amounting to a concentration of 2.4%
by weight).19/ In addition, 30 kg/MT of dissolved solids originate from the
phosphoric acid mists in the scrubbers and from excess phosphoric acid in the
reaction slurry for the MCP process.19/ A summary of the phosphorus-containing
raw wastes from food-grade calcium phosphate plants is given in Table 6-11.
TABLE 6-11.
SUMMARY OF PHOSPHORUS-BEARING RAW WASTES FROM FOOD-
GRADE CALCIUM PHOSPHATE PLANTS
Dewatering
Solids
scrubbing
Total
Process water wasted:
(liter/MT product)
2,100
2,100
4,200
Raw waste load, dissolved P04
(kg/MT product)
15
15
30
Solid wastes (kg/MT product)
10
10
Source:
Ref. 19
The EPA recammended effluent limitations (BPCTCA) for food-grade calcium
phosphates is a maximum average discharge (for 30 consecutive days) of 0.17 kg
total phosphorus per metric ton of product manufactured.20/
Atmospheric emissions--Emissions which occur during processing were esti-
mated on the basis of published datal/ and on calculation methods described
earlier in this section. A summary of the estimated emission values is given
in Table 6-12. The estimated total air emissions are 2.3 kg phosphorus per
metric ton MCP or TCP product and 2.4 kg phosphorus per metric ton DCP product.
Summary of phosphorus discharges to environment--Data on phosphorus dis-
charges to the environment which apply for 1 MT of food-grade calcium phosphate
fo Hows:
MCP or TCP production
Total wastewater losses
Total atmospheric losses
0.17 kg P \ Total P losses, 2.47 kg
2 .30 kg P J
141
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TABLE 6-12.
SOURCES AND ESTIMATES OF PHOSPHORUS-CONTAINING AIR EMISSIONS
FOR FOOD-GRADE CALCIUM PHOSPHATES
Production activity
Uncontrolled
particulate
emission
factor
(kg/Mr )
% P205
in
Estimated
level of
emi ssion
control
(%)
P emissions
after controls
(kg P/MT product)
emissions
MCP or TCP production
Drying-cooling 30 a/ 90
Bagging 0.5£/ ;'/ NA
Material handling (total) 2 -;./ NA
Total
I-'
.po
N
DCP production
Drying-cooling 30 a/ 90
Grinding 10 ~ 97
Bagging 0.5£/ a/ NA
Material handling (total) 2 ~/ NA
Total
1.3
0.2
0.8
2.3
1.3
0.1
0.2
0.8
2.4
Source:
Ref. 5.
!}./
Emission factor includes % P205.
~I
Emission factor after control.
NA = Not available.
-------
DCP production
Total wastewater losses
Total atmospheric losses
0.l7kgPl
2.40 kg P ( Total P losses, 2.57 kg P
National emission for production of food-grade calcium phosphates--The
total domestic production of these products for 1978 is about 51,000 MT. Using
the emission factors shown in Table 6-17, the total annual losses of phosphorus
to the environment from these processes are calculated to be 9 MT from discharged
wastewater and 122 MT from air emissions.
Production of Laundry Detergents (SIC No. 2841)--
Two basic types of detergent products are spray dried materials and liq-
uid detergents. The process technology involved in the manufacture of these
products is described in Reference 22. A wide variety of raw materials can be
used in these manufacturing operations. Detergents can be formulated with dif-
ferent .inorganic and organic chemicals to provide the same cleaning power and
have the same biodegradability. They can also be formulated to:
Maximize cleaning power.
Maximize biodegradability.
Minimize eutrophication potential in a specific receiving water.
Maximize cleaning power per unit of cost.
Minimize air or water pollutants and solid wastes generated by the produc-
tion process.
Although detergent companies and their suppliers have expended a signifi-
cant research and development effort to develop substitutes for phosphates in
detergent products, no replacement has been found which is both effective, and
competitive on a basis of production cost.22/ Manufacturers are generally re-
formulating with lower concentrations of phosphate, substituting nonionic for
anionic organic surfactants, and using additional amounts of alkaline builders
such as sodium silicates and sodium carbonates.
Spray dried products are reported to represent thr largest volume unit
process utilized by the soap and detergent industry.22 The principal sources
of contaminated water are washdown of the drying tower, water discharged from
off-gas scrubbers, and leaks and spills. A very small quantity of particulate
waste material is vented to the atmosphere. All waste streams are contaminated
with the detergent being produced.
143
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The "WIIU/.;H:llln~ (lL I.lquld II/-',IJI.-dlll Y dl.:ilIWil~dll.llb ,IIILI hl~;lvy-dliLy L.llIlldL"Y
detergents is conducted in relatively simple equipment for blending of the va-
rious ingredients.~ Contaminated effluent is produced by leaks Gnd spills
from the product filling line. In both the blending and filling activities,
purging of the process line between batch product runs produces discharges of
detergent contaminated water. Also, filled detergent bottles are sometimes washed
which results in additional wastewater. .
The contaminants in waste effluents from the processing of light-duty liq-
uid products are very high in surface active agents.~/ The operations conducted
for heavy-duty liquid detergents can also result in some wastewater contamina-
tion with builders such as phosphates and carbonates.
Phosphate levels found in the raw wastewaters and treated effluents from
plants producing soaps and detergents are reported to be comparable to those
encountered in the inf1uents and effluents of well operated municipal treat-
ment plants. In 1973, more than 95% of the plant effluents were being discharged
to municipal treatment p1ants.22/
Information on a representative process flow diagram for the domestic pro-
duction of phosphorus-based laundry detergents by one u.s. producer was obtained
by telephone contacts with a company spokesman. This information is presented
in Figure 6-20. Attempts to obtain similar process data from other domestic
producers were unsuccessful.
Material balance data--A phosphorus mass balance showing values which
apply for 1 MT of laundry detergent product follows:
Input
60.04 kg P
Outputs
Product
Total wastewater losses
Total atmospheric losses
Unaccounted for P
60 kg P
0.02923 kg
0.00725 kg
0.00352 kg
P} .
P Total P losses, 0.03648 kg
National emission for production of phosphorus-based laundry detergents--
The estimated domestic production of these products in 1978 is 1,860,000 MT
(Table 6-17). The total annual phosphorus discharges from these processes can
be estimated, using the emission factors in Table 6-17, to be 54 MT in dis-
.charged wastewater and 13 MT in air emissions.
144
-------
Air Emissions
0.00725 kg P/MT
Raw Materials (100%)
60.04 kg P
~
- Manufacturi ng -
p Operations -
.
(6% Total P)
Product
1 MT
60 kg P
Effluent Waste
0.02923 kg P/MT
Source: Industry contacts.
Figure 6-20.
Flow diagram for production of laundry detergent.
Metal Surface Treatment--
Phosphoric acid is used domestically in various treatment operations
(phosphoric acid baths) for plating and polishing of metal surfaces.l/ Dry-
process phosphoric acid is generally used. Four important applications are:
(a) phosphating or forming a protective coating of an insoluble phosphate
salt; (b) polishing and brightening metal surfaces; (c) electropolishing in
phosphoric acid baths; and (d) chemical plating of a nickel-phosphorus alloy
on various surfaces. All of these operations emit phosphoric acid mist into
the atmosphere.
Information obtained from industry spokemen indicate that the total phos-
phorus consumption as phosphoric acid for acid treatment of metal surfaces
will be about 34,000 MT of contained phosphorus in 1978.
Wastewater--Based on information provided by a supplier of phosphoric
acid, it was assumed that wastewater containing phosphorus is treated to con-
trol pollution and that the maximum discharged phosphorus rate is equivalent
to the standard (0.044 kg phosphorus per metric ton of acid) which applies for
production of dry-process phosphoric acid (Pacheco, J., Personal Communication,
FMC Corporation, Philadelphia, Pa., November 1, 1978). On this basis, the esti-
.mated total phosphorus discharge in wastewater is 10 MT phosphorus per year.
145
-------
Air emi ssion--The reported controlled emission rate is 0.12 kg P 20~ per
metric ton of acid consumed.i/ The estimated total phosphorus emission 1S 27
phosphorus per year.
MT
Use of Phosphorus-Derived Chemicals in Industrial Water Treatment--
In industrial water treatment operations (e.g., cooling water, boiler
water treatment, etc.) various chemical agents must be added to the water
system to control corrosion and scaling problems.23/ Some of the most effec-
tive chemical agents are phosphorus-based materials, such as polyphosphates
and phosphonates. Other control chemicals, such as chromates and zinc compounds,
are frequently used in combination with the phosphorus chemicals. The use of
these chemicals is considered necessary for proper water treatment and to ensure
against lost production time and excessive energy use.
Heat generated in many industrial processes is usually dissipated by a
water-cooled heat transfer system. In industrial plants utilizing an open re-
circulating cooling system, warm water from the heat transfer system is pumped
to a cooling tower. During passage over the cooling tower, the evaporation of
some water serves to cool the remaining water.23/ If required, additional water
is added and the cooled water is recycled to the heat source. As the water re-
cycling process continues, minerals initially present in the water will concen-
trate and, if remedial action is not taken, these minerals will eventually pre-
cipitate as scale-forming salts (e.g., calcium carbonate and calcium sulfate)
on heat transfer surfaces. This scale reduces cooling efficiency and eventually
requires .the system to be shutdown for cleaning.
As the water is passed over the cooling tower, two other processes also
occur. First, particulates are scrubbed from the air and these particles can
deposit on metal surfaces to cause fouling. Secondly, during aeration the wa-
ter becomes saturated with oxygen which increases the electrolytic corrosive
action of the water.~/ The corrosion action results in the deposition of oxides
on the metal surfaces. These coatings will impede heat transfer or reduce water
flow resulting in decreased cooling efficiency.
Effective corrosion control has been accomplished for over 20 years using
a combination of 10 to 20 ppm chromate compounds, 3 to 10 ppm phosphates, and
1 to 3 ppm zinc compounds. This combination allows cooling system operations
to utilize mild steel equipment, which is adequately protected by these chemi-
cals rather than corrosion-resistant metals.
Because of stringent water quality standards for metals in several states,
water treatment companies have been conducting research to develop nonmetallic
corrosion inhibitors. These nonmetallic agents (e.g., polyphosphates, such as
sodium tripolyphosphate) are now available and provide acceptable control of
corrosion and deposition in some industries. However, the use of phosphate and
other phosphorus-containing chemicals is also required in each of these newer
approaches (Weidman, J. G., Personal Communication, Betz Laboratories, Trevose,
Pennsylvania, January 1978).
146
-------
Phosphate additives are also used extensively for boiler water treating.
Cost effective and energy effective alternatives to the use of phosphorus com-
pounds appear to be unavailable for boiler water treating as well as for cool-
ing water service (Tuckett, W. F., Personal Communication, Phillips Petroleum
Company, Bartlesville, Oklahoma, January 1978).
Another important use of phosphorus-based deposit control agents is to
prevent deposition in gas scrubbers (Weidman, J. G., Personal Communication,
Betz Laboratories, Trevose, Pennsylvania, January 1978). Under the Clear Air
Act, the EPA has established emission standards for many industry categories
which can only be met by efficiently operating gas scrubbers. If deposition
occurs, the plants must be shutdown or the scrubbers bypassed for cleaning.
When the units are bypassed, the operator risks being in violation of the Act.
Attempts to obtain a definitive breakdown of the
treatment phosphorus chemicals in wastewater actually
owned treatment works were unsuccessful.
percentage of water
discharged to publicly
National emission for use of water treatment chemicals--Attempts to obtain
representative flow diagrams and phosphorus material balance data for domestic
water treatment systems were unsuccessful. The approximate quantity of
phosphorus-based chemicals used domestically for water treatment in 1978 is
reported to represent from 18,140 to 27,210 MT (40 to 60 million pounds) of
contained phosphorus, or about 0.8 to 1.5% of total domestic phosphorus con-
sumption (Weidman, J. G., Personal Communication, Betz Laboratories, Trevose,
Pennsylvania, January 1978). With the assumption that 50 million pounds of
phosphorus is annually discharged to the environment, an estimated 22,700 MT
were re leased in 1978. '
Domestic Sewage--
The National Commission on Water Quality (NCWQ) has reported that
the daily ,total flow from publicly owned sewage treatment plants during
1973 was about 91 million cubic meters (24,000 million gallons) and
that the total phosphorus load in this effluent was about 800 MT (880
tons).24/ Converting these values to concentration (mass of total phos-
phorusdivided by effluent volume) one finds that ,the phosphorus con-
centration in sewage treatment plant effluents for 1973 was about 8.8
mg/ liter.
The 1976 Needs Survey indicates that the total nationwide volume
of sewage collected daily in 1975 was 96,662,000 m3 (25,500 million
gallons).25/ If it is assumed that all sewage collected was discharged
as treated wastewater and that the average concentration of 8.8 mg/liter
, of phosphorus did not change, then the total phosphorus emitted from
publicly owned sewage treatment plants in 1975 was 850 MT/day (935 tons/
147
-------
day). This quantity of phosphorus represents domestic, commercial, and
industrial contributors.
When the 1976 daily phosphorus loads are multiplied by 365, an esti-
mated 310,000 MT (340,000 tons) of total phosphorus were discharged an-
nually by the sewage treatment plants. Using the population of 157,434,000
persons served by publicly owned sewage treatment plants as reported in
the 1976 Needs Survey, this quantity becomes 2.15 kg (4.7 lb) of phos-
phorus being discharged per person per year.
An overall total (household, industry, and institution) of 1.63 kg phos-
phorus per person per year is charged into sewage treatment systems.
(Fealey, T. Personal communication. Proctor and Gamble Company, Cincinnati,
Ohio.) Thus, there is a discrepancy between the quantity of phosphorus that
has been estimated to be contributed to the sewage treatment plant (1.63
kg) and that which has been estimated to be discharged from the plant after
treatment (2.15 kg). It is believed that the source of this discrepancy
lies in an underestimation of the phosphorus discharged by industrial and
commercial sources. Quantities of phosphorus from commercial and industrial
sources can be better estimated by determining differences between total
phosphorus contributed and phosphorus from domestic/household sources.
From the average annual per capita phosphorus loads indicated in Table 5-4
(0.68 kg from laundry detergent, 0.47 kg from human waste, and 0.20 kg from
miscellaneous sources; total of 1.35 kg per capita are used), it can be calcu-
lated that the 157,434,000 persons served by publicly owned sewage treatment
plants will contribute 213,000 MT (234,000 tons) of phosphorus to sewage treat-
ment facilities annually. This contribution of phosphorus to sewage treatment
plants from domestic/household sources is only part of the total load; addi-
tional phosphorus is added from commercial establishments and industry.
Typical concentrations of total phosphorus in influent to sewage
treatment plants are shown in Table 6-13. The average phosphorus con-
centration is 10.6 mg/liter with a standard deviation of 3.6 mg/liter.
Using the 10.6 mg/liter value as the representative average concentra-
tion of total phosphorus in influent and a total daily flow of 96.6 x
109 liters, the total phosphorus load to sewage treatment plants is
374,000 MT/year (412,000 tons/year). Thus the difference between total
phosphorus load and domestic/household load is the quantity of phos-
phorus contributed to sewage treatment plants by commercial and indus-
trial establishments annually, i.e., 161,000 MT/year (178,000 tons/year).
Thus, domestic/household sources contribute about 57% of the total in-
fluent load, and commercial industrial sources account for the other 43%.
The large percentage of phosphorus from commercial and industrial sources
is believed to be due to usage of phosphorus-containing cleaning compounds
in industrial plants and commercial establishments such as restaurants,
laundries, hotels, car washes, filling stations, etc.
148
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TABLE 6-13.
TYPICAL CONCENTRATIONS OF TOTAL PHOSPHORUS IN
RAW SEWAGE AT VARIOUS LOCATIONS
Location
Total P in raw sewage
(mg/9 )
Gray ling, MI
Benton Harbor, MI
Trenton, MI
Waukegan, IL
Pontiac, MI
Michigan City, IN
Babbitt, MN
Dogue Creek STP, VA
Little Hunting Creek
Rochester, NY
Seneca Fa 11s, NY
Richardson, TX
Chapel Hill, NC
Wyoming, MI
S TP , VA
10-20
7.6
11. 7
8.2
7.5
10
11
9.0
10
8
6.3
11.4
11. 3
10.4-17.5
Source:
Adapted from data contained in Ref. 26.
As discussed earlier, the annual quantity of phosphorus estimated
to be discharged from all of the sewage treatment plants is 310,000 MT/
year; the phosphorus input estimate is 374,000 MT/year. Thus, one a
nationwide basis, the average reduction of phosphorus during sewage
treatment is 64,000 MT/year, or about 17%. If it is assumed that sewage
treatment reduces phosphorus independent of source, then one finds that
phosphorus coming from domestic/household sources in treated wastewater
is about 177,000 MT/year, while that from commercial and industrial
sources is approximately 133,000 MT/year as shown in Table 6-14.
As stated above, it is estimated that nationwide sewage treatment
removes an average of about 17% of the phosphorus present in the input
sewage. This percentage represents the cumulative effect of the various
types of sewage treatment processes on the degree of phosphorus removal,
typical values of which are shown in Table 6-15. Primary treatment is
relatively ineffective towards phosphorus removal. Secondary treatment
will remove 10 to 20% of the phosphorus; however, addition of chemicals
specifically for phosphorus removal can reduce levels considerably (by
80 to.95%).
149
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TABLE 6-14.
SOURCES OF PHOSPHORUS LOADING IN TREATED EFFLUENT
FROM MUNICIPAL SEWAGE TREATMENT PLANTS
Phosphorus Phosphorus discharged in
source treated effluent (MT/year) %
Domestic/household:
Laundry detergent 75,000 24.2
Automatic dishwashers 13,000 4.2
Personal sewage 71,000 22.9
Garbage disposals 18,000 ~
Total domestic/household 177 ,000 57.1
Commercial/industrial 133,000 42.9
Nationwide total 310,000 100.0
TABLE 6-15. EFFECTIVENESS OF PRIMARY AND SECONDARY TREATMENT PROCESSES ON
PHOSPHORUS REMOVAL WITH AND WITHOUT CHEMICAL ADDITION
Percent removal
Phosphorus Suspended solids BOD
Treatment Without With Without With Withou t With
Primary treatment 5-10 70-90 40-70 60-75 25-40 40-50
Secondary treatment:
Trickling fi 1 ter 10-20 80-95 70-92 85-95 80-90 80-95
Activated sludge 10-20 80-95 85-95 85-95 85-95 85-95
Source: Ref. 26.
Unfortunately, the number and location of plants employing chemical addi-
tion for phosphorus removal is not readily available. Therefore, in order to
estimate the phosphorus emissions from publicly owned sewage treatment plants
on a regional basis, the nationwide value of 17% waS used to estimate average
percent phosphorus removal from the three types of sewage treatment listed in
the 1976 Needs Survey.25/ The procedure for estimating regional quantities of
phosphorus removal is discussed in the following paragraphs.
150
-------
In the 1976 Needs survey,25/ the population (157,434,000) served by
various levels of sewage treatment has been broken down by states; this
population represents 72.6% of the nation's population. The percentage
. has been further broken down into types of sewage treatment used. Nation-
wide, 18.6% of the population is served by less than secondary treatment
(assumed to be primary treatment), 15.0% by secondary treatment, and 21.1%
by tertiary treatment.25/ Because of the manner in which population data
were gathered and interpreted, the total percentage of the population
served by municipal sewage treatment plants is only 54.7% rather than
72.6%. Thus, there is some discrepancy in the information concerning the
distribution of sewage treatment processes in the country; this discrepancy
is acknowledged and explained in the Needs Survey.
The 1976 Needs Survey used the term "tertiary treatment" to mean removal
of BOD (biological oxygen demand) and suspended solids to levels which are
less than those found in secondary treatment effluent. Thus, phosphorus re-
moval per se is not a part of the Needs Survey definition of tertiary treat-
ment. However, s9me phosphorus removal would be expected in treatment plants
which produce effluent of better quality than secondary treatment. From data
in Table 6-15 for phosphorus removal in primary (average 7% removal) and sec-
ondary (average 15% removal) treatment, and the volume data for primary and
secondary treatment as reported in the Needs Survey, it was possible to esti-
mate the fraction of the 310,000 MT/year of phosphorus emitted in effluent
from these types of plants. The remaining phosphorus tonnage was assumed to
be emitted from plants with tertiary treatment. Using these data to estimate
a phosphorus concentration in the effluent and comparing this estimate with
the 10.6 mg/liter in the influent (see p. 149), a value of about 35% phos-
phorus removal is obtained from wastewaters undergoing tertiary treatment.
Thus, on a nationwide basis, the average values of phosphorus removal by va-
rious categories of treatment processes are:
Treatment category
Phosphorus removal (%)
Less than
Secondary
Tertiary
secondary (primary)
7
15
35
Using these assumptions, formulae for estimating
sions from publicly owned sewage treatment plants due
household and commercial/industrial sources have been
formulae are:
phosphorus emis-
to domestic/
developed. The
151
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Domestic/household:
[(0.93 x % pri) + (0.85 x % Sec) + (0.65 x % Ter) ]
pop x 1.35 x ~
(% Pri + % Sec + % Ter)
x 0.001 = Pd
where:
Pop = population (Table 3, 1976 Needs survey~25/
1.35 = kg P contributed per capita per year,
% pri = percent of population receiving primary sewage treatment
(Table 3A, 1976 Needs survey),~/
% Sec = percent of population receiving secondary treatment
(Table 3B, 1976 Needs survey),25/
% Ter = percent of population receiving tertiary treatment
(Table 3C, 1976 Needs survey),25/
0.001 = conversion factor for kg to MT, and
Pd = total phosphorus discharged after treatment from domestic/
household sources, MT/year.
Commercial/industrial:
(Total flow) - (Pop x 380)
x 365 x 12.0 x
[(0.93 x % Pri) + (0.85 x % Sec) + (0.65 x % Ter) 1
l (% Pri + % Sec + % Ter)
x 10-9 = P
c
where:
Total flow = average daily flow in liters/day (Table 15, 1976
Needs survey),25/
Pop = population served (Table 3, 1976 Needs survey),25/
380 = volume (liters) of water contributed per person
per day,
152
-------
365 = days in a year,
12.0 = concentration (mg/1iters) of phosphorus in com-
mercial/industrial inf1uent,*
%Pri = as defined above,
% Sec = as defined above,
% Ter = as defined above,
10-9 = conversion factor for mg to MT, and
Pc = total phosphorus discharged after treatment from
commercial/industrial sources, MT/year.
Using these formulae, the estimates for 1975 and for 1978 arranged
according to region are presented in Table 6-16. In addition to the assump-
tions already discussed, the estimates assume that the fraction of the
commercial/industrial phosphorus load to the sewage treatment plant is dis-
tributed in the same way as for the domestic/household phosphorus. In addi-
tion, the estimates do not reflect the banning of phosphate in detergents
in certain states or particularly stringent state effluent standards. Na-
tionwide phosphorus values in Table 6-16 do not add up to totals estimated
earlier because of rounding errors, and the use of "average phosphorus re-
moval for the three types of sewage treatment. Also, contributions from out-
lying areas, e.g., Puerto Rico, the Virgin Islands, Guam, American Samoa,
and Pacific Trust Territories, have not been included.
The preceding discussion has been based on information relating to
the country's population served by municipal treatment plants. This popu-
lation is only 70% of the total. The remaining 30% represents persons
who do not contribute to municipal sewage treatment plants, and presumably
*
The value of 12.0 mg/liter phosphorus input to sewage treatment plants was
established in the following manner. Annual phosphorus contribution from
commercial/industrial sources is estimated to be 161,000 MT/year, or about
440 MT/day (see p. 149). The total daily volume of collected sewage is
96.66 x 109 liters, of which 59.82 x 109 liters come from domestic/house-
hold sources using the rule of thumb value of 380 liters/day (100 gal/day)
and 157,434,000 persons. Thus, the daily volume of sewage to publicly
owned treatment plants is 36.84 x 109 liters/day. From daily loads of
phosphorus (440 MT) and daily volumes (36.84 x 109 liters), one calcu-
lates that the average concentration of phosphorus in influent from
commercial/industrial sources is 12.0 mg/liter.
153
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TABLE 6-16.
PHOSPHORUS LOAD ESTIMATES FOR MUNICIPAL SEWAGE TREATMENT PLANTS
Estimates for 1975 Estimates for 1978~/
Treatment plant effluent, Treatment plant effluent,
MT of total P/year MT of total P/year
P, domestic P, commercial P, domestic P, commercial
. a/ and and and and
U.S. reglon- household industrial Total P household industrial Total P
Northeast 5,416 7,717 13,133 6,149 7,863 14,012
Middle At lantic 35,351 26,656 62, 007 3 6 , 506 26,793 63,299
South Atlantic 21,813 13,086 34,899 23 , 928 13,874 3 7 , 8 02
t:;; East North Central 34,369 41,322 75,691 32,851 41,604 74,455
+:-
East South Central" 7 , 396 11 ,380 18,766. 8 , 3 09 10,716 19 , 02 5
West North Central 15,535 7,595 23, 13 0 16,276 8,644 24, 92 0
West South Central 15,207 4, 586 19,793 16,666 6,301 22,967
Mountain 8,194 5,225 13,419 9,073 5,598 14,671
Pacific 25 , 981 9,977 3 5 , 958 27,522 11,579 39, 101
Total United States 169,000 128,000 297,000 177, 000 133, 000 310,000
(rounded to nearest
1, 000 MT)
~/
A table showing the state-by-state loading estimates for 1978 is given in Appendix B.
-------
use septic tanks or small community lagoons for sewage treatment. Base-
line information for effectiveness of these treatment systems in terms of
phosphorus removal is lacking, and therefore no estimates have been made.
In the case of septic tank treatment, phosphorus loads are likely to be
small. It is generally assumed that practically all phosphorus is removed
from water treated by soil in a septic tank system. However, in certain cases
where soils are excessively sandy, it is questionable whether this assumption
is valid.
The procedures developed for the 1975 estimates of state and regional
phosphorus emissions from publicly owned municipal treatment plants have
been used for the 1978 estimates. The differences between the 1975 data
and the 1990 projections in the Needs Survey have been linearly extrapolated
to 1978 population served by municipal treatment plants, flows collected,
and percent of plants with primary, secondary, and tertiary treatment. In
addition, the EPA has developed an estimate of the publicly owned treatment
plants which will require phosphorus removal by 1990. (Memos: J. Yance to
J. Welch, OTS; 9/9/78, 9/1/78.) Thus, the assumption was made that these
plants did not have phosphorus removal capability in 1975, but that some
progress had been made between 1975 and 1978 to achieve the needed phosphorus
removal. The 3 years of progress were assumed to have achieved 20% of the 15-
year goals (i.e., the 1990 goals for phosphorus removal).
The results of these calculations based upon the aforementioned ex-
trapolation and assumption are shown in Table 6-16. In general, there is
a little more phosphorus being discharged in 1978 from publicly owned
sewage treatment plants than was the case in 1975. This greater quantity
is not due to less efficient treatment; rather, it is due to the increased
population served and the increased capacity of publicly owned sewage
treatment plants.
This trend is also seen when the 1990 projections in the 1976 Needs
Survey are used to project phosphorus emissions in 1990. The nationwide
estimates for phosphorus emissions for 1975, 1978, and 1990 are summarized
below.
1975 1978 1990
Source MI'/year MI'/year MI'/year
Domestic/household 169,000 177 ,000 193,000
Commercial/industrial 128,000 133,000 148 , 000
Total 297,000 310,000 341,000
155
-------
Inadvertent Point Sources--
The estimated national phosphorus emissions from inadvertent point
sources for 1973 were taken from the 1iterature.~/ This information was
updated by adjusting the emission levels according to reported changes
in the respective production or consumption rates for each source between
1973 and 1978. For example, it was estimated that the national production
rate for iron increased by about 7% over this period. Thus, the 1973 emis-
sion rate of 2,800 MT/year was increased by this percentage (2,800 x 1.07)
to obtain a value of 3,000 MT of phosphorus discharged in 1978.
A tabular summary of all estimated national point sources, including
inadvertent sources, is shown in Table 6-17.
Conclusions for National Assessments
A summary of the estimated national phosphorus discharges to the en-
vironment for 1978 is presented in Table 6-18.
The aggregate of the nonpoint source discharges accounts for 87.6%
of the total estimated national emissions of about 2.9 million metric
tons of phosphorus. The major contributors in this category are cropland
and runoff (,,-, 49%) and pasture and rangeland (,,-, 34%). About 99% of the
total phosphorus discharges from nonpoint sources comes from runoff
water with the balance attributable to air emissions from inadvertent
sources.
In contrast to the nonpoint source discharges, the estimated aggre-
gate point source phosphorus discharge accounts for only 12.4% of the
total national emissions. The phosphorus loading in municipal sewage
treatment effluent accounts for the bulk (10.6%) of the discharges in
the point source category. The total air emissions from point sources ac-
count for about 55% of the national total air emissions and the quantity
of identified phosphorus in solid wastes (32 MTphosphorus per year) is
negligible.
The top 10 ranking of factors in descending
terms of magnitude of phosphorus emissions) on a
on p. 161.
order of importance (in
national level are shown
156
-------
. TABLE 6-17.
ESTrHA'n::l> NATiONAL POINT snURCE IIlSCIIARCES OF TOTAL PIIOSPIIORUS TO TilE ENVIRONMENT IN 1978
Oischa rRes to environment
Dlschanr.ed wastewater Air emissions
Product. mal\Ufact.uring, r.J.l.e E..tss Lon £miss ion Solid Total
Base d;] ta Exttapoiation E'itimBte factor factor wastes. d lscharge
SIC for Y~8r ( fa!.: tor or for 1.,tJ~1 O.OO~ 15 0.14'1 L ,ISO 0 1,165
(of 1'2(5)
..... 2048 l>eflilorinated phosphate rock (1 i Vc~ to..;k
VI and poultry feeds) 272 (1'J77)~! I.O~I 271 0.31 90 2.2 600 0 690
-...J
2048 Anlmal-feed-grade calcium phosphates 615 (1977)~1 1.0<::/ bl5 0.026 17 2.6 1,651 0 1,668
B. subtota 1 18'1 5,087 0 5,267
C. Industrial manufacturing,
2819 Elementa 1 phospht.rus 475 (1'174)£1 Uccrcas~ of 462 0.15 6'1 0.64 296 0 365
o. 7'l.IYI"£1
2819 Dry process phospho r ic add 857 (I 974) llic [-ease of 883 0.U4l, 60 0.57 770 0 830
(of P205 )~.I (I. 17) yr!E.I (of P2°:,)
281'1 Phosphorus peoLoxid~ 8~1 U.024 0.2 8.50 68 0 68
2819 Phosphol"IIS trichluride Capacity (1978) Ass,uned 97.5, 'J6.4 0.05 10.8 1,041 2 1,048
91L88U II t: f I j Zit t ion~/
2819 Phosphorus oxych lori\1e Capae lty (1978) Assumed 951. 79.3 n.05 4 4.74 376 0 380
83.46f.! util L-ationgl
'2819 Phosphorus pentasu I fide Capacl t V (978) AS5\1m~d 967.. 76.6 0.0'19 15.14 1,160 30 1,193
79.8f.! uttll.,ations,1
2841 Sodil"" tripolyphosphate (S1'PP) 829 (1971 )~I 1.0£1 829 0 0 0 0 0 0
-------
TABU;; 6-17.
(con tlnued)
Toul
disch~rge
MT of
phosphorus
o
707
SIC
No.
Industrv or activity description
2841
Sodium phosphates (excluding STPP)
2819
Food-grade-calcium phosphates
2841
Laundry detergents (phosphorus-based)
Direct acid treatment of metal surfaces
(with "31'04)
Phosphorus-based water treatment chendcals
C.
subtotal
D.
Municipal sewage treatment effluent
E.
Inadvertent sources
Iron manufacture
Steel manufacture
~
V1
(X)
Cement manufacture
Refuse incinerstion
Fuel oil comhustion
Coal combustion
E.
subtotal
National total t point source
Base data
for year (
103 Iff/Vr
339 (l973)~/
48 (l976)~/
Discharged
Emission
Extrapolation Estl'Mte factor
[actor or for 1978 kit p/MT
comment 103 MT/Vr produc t
Increase' of 353 0.004
47./yr~1
Incrf"8!;e of 51 0.17
3. 57./yr~1
1,860!!/ 0.029
Con!;umption Y. 0.041,
rote' (of P)~/
Consumption 22.7
rate (of p)!!1
wlIfitewater
MT of
phosphorus
54
10
22.700
22,915
110,000
Da ta not
available
Data not
~vailablc
Da ta not
avallahle
Oata not
avallable
Oata not
avail~ble
Dilts not
available
1)) ,126
Discharges to environment
Air emissions
Emls s ion
factor
S"lid
o
131
9
kg p/MT MT of
product phosphorus
2.00 706
2.40 122
0.007 13
0.11 27
o 0
4,579
wastes,
Iff of
phosphorus
o
67
3,000 Not
applicable
280 Not
applicable
190 Not
applicable
45 Not
app If cab Ie
1,900 Not
app licab Ie
6,000 Not
app I ieah Ie
11,415
26,346 32
o
J7
o
22,700
32
2T.526
110,000
3,000
280
190
45
1,900
6,000
Tl;4T5
359,695
!!/ Reference 9.
'E/ Reference 13.
sJ Re ference 14.
~/ Reference 17.
,!/ HRI interpretation of data collected
Research Institute, 1977 ) .
1,.1 Reference 27.
p,/ Reference 12.
1!/ Industrial contacts.
fran industrial contacts and from a.emical Economics Handbook (published by Stanford
-------
TABLE 6-18.
SUMMARY OF ESTIMATED NATIONAL PHOSPHORUS DISCHARGES TO ENVIRONMENT IN
1978
Phosphorus discharged (metric tons)
Air Solid
Activity
Nonpoint source
runoff water
Cropland
discharges for
Pasture and rangeland
Forest land
Livestock feed lots
t-'
\.J1
\0
Urban
Roadways (rural)
Nonpoint inadvertent sources
Nonpoint subtotal
Point Source Discharges
Phosphate rock mining and
beneficiation
Production of phosphate ferti-
lizers and intermediate
chemicals
Production of animal feed
Production of phosphorus and
derived chemicals
Wastewater
1,433,400
985,600
84,300
28,700
18,400
1,000
2,551,400
222
73
107
151
emissions
Data not
available
Data not
available
Data not
available
Data not
available
Data not
available
Data not
available
21,410
21,410
5,265
2,836
2,251
4,539
wastes
Data not
available
Data not.
available
Data not
available
Data not
available
Da ta not
available
Data not
available
Data not
available
None
o
o
o
32
Tota 1
phosphorus
discharged
(me t dc tons)
1,433,400
985,600
84,300
28, 700
18,400
1,000
21 ,410
2,572,810
5,487
2,909
2,358
4,722
% of
national
phosphorus
discharge
48.9
33.6
2.9
1.0
0.6
<0.1
0.7
87.6
0.2
0.1
0.1
0.2
-------
TABLE 6-18.
(cont inued)
Activitv
.....
(j\
o
Production of laundry
detergents
Direct acid (H3P04) treatment
of metal surfaces
Phosphorus-based water treat-
ment chemicals
Inadvertent sources
Municipal sewage treatment
effluent
Point source subtotal
National total
Phosphorus discharged (metric tons)
Air Solid
Wastewater
emissions
wastes
Tota 1
phosphorus
discharged
(metric tons)
% of
national
phosphorus
discharge
54
13
o
67 <0.1
37 <0.1
22,700 0.8
11 ,415 0.4
310,000 10.6
359,695 12.4
2,932, 505~/ 100.0
10
27
o
~/
22,700
11 ,415
310,000
333,317
26,346
32
2,884,717
47 , 756!/
32
Rounded to nearest 1,000 metric tons.
-------
I -
1. Cropland runoff
2. Pasture and rangeland runoff
3. Xunicipal sewage treatment
effluent
4. Forestland runoff
5. Inadvertent sources (total for
point and nonpoint)
6. Livestock feedlots
7. Phosphorus-based water treat-
ment chemicals (usage)
8. Urban runoff
9. Phosphate rock mining and
bene ficia t ion
10. Production of phosphorus and
derived chemicals
Tota 1
Summary of Airborne Phosphorus Pollutants
Table 6-19 shows the estimated annual
tion of the total phosphorus discharged as
the data was taken from Table 6-17.
Estimated % of
national phosph0rus
discharge
Type of source
point (P) or
nonpoint (NP)
48.9
33.6
10.!>
NP
NP
?
2.9
1.1
NP
P + NP
1.0
0.8
NP
P
0.6
0.2
NP
P
-2.:l
P
99.9
quantities and percentage distribu-
air emissions in 1978. A portion of
Coal combustion is estimated to be the largest single source of phosphorus
air emissions (about 23% of national P air emissions) in the United States. This
emission occurs as fly ash in stack emissions from combustion. The second larg-
est source (about 20% of the national total P air emissions) is phosphate rock
mining and beneficiation activities; phosphorus air emissions from these opera-
tions (i.e., mining, handling, drying, calcining, crushing, and grinding) occur
as phosphate rock particulate. The estimated third largest source (about 11% of
the national total) is iron manufacture; the emission occurs at particulate mat-
ter (e.g., ore dust). Fuel oil combustion ranks fourth and represents about 7%
of total phosphate air emissions. The manufacture of animal-feed grade calcium
phosphates is estimated to account for about 6% of the national air emission of
phosphorus. All other estimated source quantities of phosphorus in air emissions
are less than 5% of the total national phosphorus air emissions.
Essentially all phosphorus air emissions occur as various particulate forms
of phosphorus compounds (e.g., product particulate matter).
At present (1978), there are no air emission control standards for phos-
phorus compounds in the United States because these air emissions of phos-
phorus compounds do not create any known problem (Crane, G. B., personal com-
munication, U.S. Environmental Protection Agency, Industrial Studies Branch,
Research Triangle Park, North Carolina, December 1978).
161
-------
siC
~"!£~--
1/./")
!g/4
:!tlll.
11:1/4
1871.
:!tS!4
lO:'d
l(IMJ
:~I:II t.I
ldl Y
nH'J
1819
~li I 'J
t-' 181')
0\
N 'lti/..t
L841
?H loJ
~841
TAIIIJ~ 0-1 'J.
I'.STIt1A'I'I~III~IIJ\fHITII:, ,\NII IHSritlUUrltifl 0'" Tor,\1 l'IIO:il'UORII:;
() I :;CI!AH{;lW AS A lit Ef'1I s:; 1 ON~j IN TilE IItUTl',1I :;'1'1\'1'1':: Itl ,tj IK
-----------=-=--=--_.
-="':,~-==-~,--=-.=.~''::.='''=-.- -===---= '-=='".,;..=
At r t~ml ss 1"11:,
1.. ..( nat 10118 I
l'n:..Jumlllallt fl)rm(s) of r-hose!luruti in air .!:~!.!..~!!!~'}':!
'j.1(15 lIJ,tJ8 l'l.rt h:u In[.:: I ph"Ii(lh:lt~ (l)(,k)
',III)") 4.16 I'ar!- I~u lall' Il.Ol:k dust and iH.ltl mist)
I, 0,11:' 1'..r[ Il'ulatt' (acid a~r"sl)l s an" 1111 :its)
1 HJ U,(,q 1'lIl'ltculLlh! (phf}~plldtc rllck aud I'rodut.~t J
'V, 1.17 1'1Ir[ h:lIlilte (plltlsplwtc rock and product)
/u 0.1/ 1',1rl ieulate C plh'$phat~ ruck <.Ind proJuc t )
1,15(1 4.')6 1'tltu;t)
I:!:! 0.1.6 I'arr.lculatl:! (1J1'tuluct)
II U.U5 1';ll"l b.:ul1Jt(. 'I'l"tlduct)
" U.I0 !'flrLh:ulat~ 11131'°4)
" U tj'jt appl leitLle
'J,OOU 11.19 l'artlt.'uIHLL" (ore. t tc. I
:~KU J .116 l'IIL"t lClllatl'
11)11 O.l'.! 1',11"1. ICII tall' ,fly .,sh)
45 O.tl ('..1't jl"ul:Ilt-' (f 1'1 d~h)
I.C)(JII 1.11 (Juku"""11
_6.uII0 ..1~ 11 I'arllnti/ite Ofly :I~")
.!6. J5u IOU.OII
HI' "t I,Iwt>llhllrus
IntlII~lry_~~':..!'y'!'!y'" JC:-i,:ri.e~!!--_- ---------~~~!~ ___atr_~£~I~
A.
!!~~~)!.!!!_~;!
l'husph,.L.. Hid.. mlnill~' "'lid L"lIcl t..-'...1101" I... .1\ td
SIIIH'rpll,':;pIUI1"11.. ;lC III
N"I"m;.1 :>ujI,:qJhllSphiJlL'
fl'l"I,. sUlh'q,h.,ql'l/i-llc: c;TS(' pr'lct..:;~
!{IJI' pl"h:CS.s
AIIII"10 I tllll ph'.sph..t.,
IIcfltH,["tU:'lcd ph"~I'IIo,lt. rodl lallimal It.t..!)
Aniu.al .f",',1 ~ru.lc c,il,,11II1I 1'1"':;l'lhlll'~
to,lt"m':lIta I ph..sphuJ"u:;
Ol'" Vn','css phusphori.' h,t,1
lihl ~1I1'or~IS pt"nt ":t t ..t,.
111U~ph"rus trlt...hl.u'I,h.
l'hlJ~plltlnls o1'.ych 1 ur I d.,
l'h'l:>plhJ[IIS pt'lIt.'1~1I1 fide
~"Jlom lripulyplwsl'lwl., (:;"'1'1')
'~jo,lIulil I'htl::lphLllt'S (t!X..:llldilig STI'P\
""h'd-/!.l'"dl~ t.'a)ctuUl 1,laoslll."l,~S
l.alllhiry 1.1t.I:l'r1;cllt~ (l'h.'spl..'rlls-hasl',I)
lJared- ;1I'jJ lrt';lllu"lIl ut ...t'l.ds twlth IIjl'o(,'
11,,,sphorlls-I.HJ:,c,1 \~...It,,, llt'HlUto'nt ..lwIIIJ,'al,~
II.
~~!:!.:!!Le~~ ~.!!!'~.::
Il"'O IIl.:HII.f:I.;lu['.'
Slt:t"1 111...11111(;."111["\'
C""~'lIl 1II,IIIIIf,ll'tlll"C
It... fllst' ill": ill.'I';ll i"l1
hil'I "i I "'III),II:;ll,'1I
Cu" I ~"III),II:,t lUll
"'--="''''' ~-=-.='.~.-'
-------
REGIONAL QUANTIFICATION OF PHOSPHORUS SOURCES
Most of the data on national assessment 0'£ phosphorus losses to environ-
ment developed in this report can be applied directly to support the quantifi-
cation of emissions in regional areas. This relationship exists because most
of the point source data apply to representative model production plants (based
on 1 MT of product). The emission factors (Table 6-17) can be readily applied
to provide estimates of phosphorus discharges for various known production lev-
els. The two key types of data required to prepare these estimates are produc-
tion or consumption rates and unit emission rates for phosphorus. Also, the
informationl/ on nonpoint phosphorus sources is subdivided into data for minor
basins, major basins, state and national categories; these subdivisions are
amenable to use in studies of specified land areas in the United States.
A discussion of the general methodology suggested for development of re-
gional assessments of environmental phosphorus discharges is presented in this
subsection. As an example case to illustrate the application of this methodology,
an estimate of the total phosphorus discharge for the state of Florida in 1978
is developed and described. These same procedures could be applied equally well
to other land areas of interest, such as various drainage basins, etc., provided
that point source data on production and consumption rates are available for
industries of concern and nonpoint source loading or land use data are avail-
able.
Florida was selected as an example case because many companies operate
phosphate rock mining and processing facilities within this state. Processes
of interest include the mining and beneficiation of phosphate rock and the pro-
duction of elemental phosphorus, wet process and dry process phosphoric acid,
superphosphoric acid, all types of phosphate fertilizers, defluorinated phos-
phate rock (animal feed), and feed grade calcium phosphates. The majority of
the Florida phosphate rock and phosphate fertilizer processors are located in
the central portion of the state (mostly in the adjoining counties of Polk,
Hillsborough, Hardee, Manatee, Suwannee, and Hamilton) and comprise a rela-
tively small land area within the state.
These estimates account for all principal sources of phosphorus release.
Quantifications of Nonpoint Sources
The estimated quantities of phosphorus discharged from nonpoint sources
to receiving waters in Florida are as shown in Table 5-20.11
Inadvertent Losses from Nonpoint Sources in Florida--
Estimat~d national data (1978) for phosphorus air emissions were shown
in Table 6-1. A brief discussion of estimates for these sources in Florida is
provided in the following paragraphs.
163
-------
TABLE 6-2 o.
ESTIMATED NONPOINT SOURCE DISCHARGES OF TOTAL PHOSPHORUS
TO THE ENVIRONMENT IN FLORIDA IN 1978
Source activity or area
Discharges to
metric tons of total
Discharged water
environment,
phosphorus per year
Air emissions
A.
Runoff discharges
Cropland
Pasture and rangeland
Forestland
Livestock feedlots
Urban runoff
Roadway runoff
4,650
12,930
830
150
510
50
Data
i
not available
1
I-'
a-
~
Subtotal for A
19,120
B.
Inadvertent sources
Windblown soil
Fertilizer application
Agricultural burning
Forest fires
(field spreading)
l'
Data not applicable
t
SS
42
32
235
Subtotal for B
364
Sources:
Midwest Research Institute data.
-------
Windblown soil--The phosphorus release in these emissions can be estUnated
on the basis of relative land areas of cropland in Florida and the nation. The
acreage of cropland in Florida represents 0.88% of the national total.i/ The
national emission is estimated to be 6,300 MT phosphorus (Table 6-1). The esti-
mated total annual quantity of phosphorus from this source in Florida is about
55 MT.
Fertilizer application (field spreading)--The national emission is esti-
mated to be 4,800 MT phosphorus (Table 6-1). From the ratio of Florida cropland
area to the national area, the approximate discharge in Florida can be calculated
to be approximately 42 MT.
Agricultural burning--On a national basis, the estUnated phosphorus
sion is 3,600 MT (Table 6-1). Using the ratio of cropland areas (Florida
national), the emission in Florida can be estimated at 32 MT phosphorus.
emi s-
versus
Forest fires--The national emission rate is 6,700 MT of phosphorus (Table
6-1). Based on the extent of forested areas in Florida and nationally and the
national emission rate (Table 6-1), the state emission can be ~stimated to be
about 235 MT phosphorus.
Quantification of Point Sources in Florida
The estimates of phosphorus released by specified point sources in Florida
in 1978 were based primarily on the national emission factor data shown in
Table 6-17 and on the relative national and state production or consumption
capacities. Information concerning production and consumption rates were ob-
tained fr~ the literature,27/ from contacts with the Florida Chamber of Com-
merce (Tallahassee), and from contacts with industry representatives. An exam-
ple of the estimating procedure follows.
EstUnated total production of phosphate rock for 1978, as shown in Table
6-17 is 50,348,000 MT. On the basis of relative national and state production
capacities,27/ the Florida share of production in 1978 can be estUnated at
about 76.3% or 38,416,000 MT.
The losses of phosphorus to the environment can be estimated on the basis
of the unit emission rate data shown in Table 6-17. The rate of discharge in
wastewater is estimated to be 0.005 kg phosphorus per metric ton of phosphate
rock product. The total phosphorus discharged is estimated to be 190 MT.
The estimated air emission for F1ori~a,
phosphorus per metric ton product. Thus, the
to be 3,460 MT phosphorus.
as shown in Table 6-3, is 0.09 kg
total air emission is calculated
165
-------
Data provided in the literature1l! show that in 1977 there were no pro-
duction plants located in Florida for the following products: dry process
(furnace) phosphoric acid, sodium phosphates, phosphorus trichloride, phosphorus
oxychloride, phosphorus pentasulfide, phosphorus pentoxide, and food grade cal-
cium phosphates. It was assumed that the same situation applies for 1978.'
The estilnated point source discharges of phosphorus in Florida are tabu-
lated in Table 6-21.
Conclusions for Regional Assessment
The estimated phosphorus discharges for the state of
in Table 6-22. The estimated total phosphorus emission is
about 1.2% of the national total.
Florida are summarized
about 34,100 MT or
The aggregate nonpoint source discharges account for 57.1% (- 19,500 MT
phosphorus) of the estimated total phosphorus emissions in Florida. In this
category, the runoff water discharges of phosphorus represent about 56% of the
total emission for the state and the inadvertent nonpoint sources represent
about 1%.
The total discharge from point sources in Florida amounts to about
14,600 MT phosphorus (42.9 of the entire discharge for the state). Major point
source emissions are sewage effluent (21.0%), phosphate rock mining and bene-
ficiation (- 11%), production of animal feed (-5%), and production of phos-
phate fertilizer and intermediate chemicals (4.2%). Inadvertent point source
discharges represent approximately 1% of the total for the state.
The Florida distribution of emissions is quite different from that which
applies for the nation. For example, in the national assessment, the ratio of
total nonpoint to total point emissions was about 7 to 1. In contrast, for
Florida the nonpoint source to point source emission ratio was about 1.3 to
1. The cropland runoff emissions of phosphorus are about 49% of the total in
the national assessment and only about 14% of the total for the state assessment.
A contrast also exists for the point source discharges. In Florida, sewage
effluent accounts for 21% of the total state phosphorus discharge. while on
a national basis, the corresponding distribution is only 10.6%. Also, phosphate
rock mining and processing and fertilizer and feed production in Florida account
for a much higher proportion of total phosphorus emissions than in the case
for the national assessment (20% versus about 0.4%).
The 10 largest environmental pollution factors in Florida in terms of total
phosphorus discharge are listed below in descending order of importance. The
estimated percentages of national phosphorus discharge are shown for comparison.
166
-------
TABU: 6-21.
F.3TIHATED POINT SOI/RCE IJISCIIAFGF.S Of TOTAL PHOSPfl.1RUS
TO TilE ENVIRONHFNT 111 FWRIIJA 111 1978
SIC No.
Estimated production DisctlsrKes to envIronment (HT of total p/yr)
rat...~ !-or Florida 1978 Oischarged Total
Industry of activity rtescrLption (10 I ~rr! yr) W;Jstewater Ai r Ct"1 s s lon5 SQlfd wa:;tcs dlscharg~
A. PhosphaLe rock mining and b<"wUcI aUolt 18,416 L90 .',460 0 3,6~(I
B. AgrIcultural CC"'3UfT1pt ton of phoc;pha te rock/
manufactutLnJ; operations
Wet process phosplloric acLd J,f\14 12 6')2 0 (,1/.
:;I'perphosphoric acid 205 fJ l 0 1
Normal .uperphusphate 62 () 29 0 29
Trip I e .upe .-phospha te 1,26' < I J20 0 120
Ammonium phosphate l,J611 /) 44J 11 449
(o( P20S)
Del t..ortnate" phosph.".. rQck 2.J7 711 522 0 600
(ll vestock an" pou llry (e"ds)
Anlm.11 teed ~l"dde calciulI1 phosphatee; ~ -1..Q L,O;O ...2- l,040
Suhtot,,1 (or B 7,1'.7 126 2,947 II 1,1)7 \
C. Industrial manuf.1r.:turlng
EJemellta) phosphorus 4l h 21, 0 J2
Ory proces" phosphor! c acid II f) II 11 0
Phosphorus peltto" lde (I ') 0 0 0
Phosphorus t rich lodde (I n () 11 ()
rhospllOrus "xych lur Lde II 0 tI 0 0
Phosphorus pentasul lLd.e (\ f) 0 () Q
Sodium phosphates (including STPP) 0 'I 0 0 r)
Food grade ca Idum phosphates U 0 f) (1 0
Phosphorus-based laundry d~tp.rgents AfJ 1 < I () 1
Direct a~id (H3P04) treatment of metal ) 1 OJ 0 4
surfaces (consumptLon)
Phosphorus-bas"d water tre
-------
SUMMARY OF ESTIMATED PHOSPHORUS DISCHAe:;ES
TO ENVIRONMENT IN FLORIDA IN 1978
TABLE 6 -2:1.
% of total
phosphorus dis-
charge for
Florida
TOla 1 phosphorus
discharged
(MT)
Phosphorus discharged (NT)
Wastewater Air emissions Solid wastes
Activity
Nonpoint source discharges from runoff
~
Crop land
Pasture and )"angeland
Forestland
Livestock feedlots
Urban
Roadway
4,650 13.7
12,Q30 37.9
830 2.4
150 0.4
510 1.5
50 O. 1
-ill -.h.!.
19,485 57.1
3,650 10.7
1,433 4.2
1,(,40 4.8
32 0.1
I < 0.1
4 < 0.1
227 0.7
403 1.2
7,177 21.0
14,612 42.9
34,lOoi!l 100.0
1 I
Not applicable
1 Not app licable
1
365
365 None
3,460 0
1,396 0
1,552 0
26 ()
< I 0
3 0
4,(51)
12,930
830
150
510
50
Nonpoint inadvertent
sources
19,120
Nonpoint subtotal
t-'
'"
(XI
Point sour~e discharges
Phosphate rock mining and beneficia-
tion
. Production of phosphate fertilizers
and intermediate chemicals
Production of animal feed
Production of phosphorus and desired
chemicals
Production of laundry detergents
Direct acid (H3P04) treatment of
metal surfaces
Phosphorus-based water treatment
chemicals
Inadvertent sources
Municipal sewage treatment effluent
190
38
88
6
227
403
7,177
7.772 6,840 -SL.
26, 90r~1 7,20~1 0
Point source subtotal
Total for Florida
2.1
Rounded to nearest 100 MT.
-------
Florida activity or item
Estimated % of
Florida phosphorus
discharge
Estimated % of
National phosphorus
discharge~
1.
2.
Pasture and rangeland runoff
Municipal sewage treatment
effluent
Cropland runoff
Phosphate rock mining and
beneficiation
Animal feeds (feed grade calcium
phosphates and defluorinated
phosphate rock)
Phosphate fertilizers and inter-
mediate chemicals
Forest and rangeland runoff
Inadvertent sources (total for
point and nonpoint)
Urban runoff
Phosphorus-based water treatment
chemical s
1.5
0.7
0.6
0.8
37.9
21.0
33.6
10.6
3.
4.
13.7
10.7
48.9
0.2
4.8
5.
1.0
6.
4.2
0.2
2.4
2.3
2.9
1.1
7.
8.
9.
10.
Total
99.2
99.9
~/
Percentage for the type of activity or item on a national basis.
Rational and Ranking Order for Assessing Regional Sources
In the national
of phosphorus in the
of priority to those
magnitude and nature
emission study described
environment were studied
categories which deserve
of their emissions.
earlier, all principal sources
without regard to any assignment
special attention because of the
In any regional study, such priority can be assigned if information con-
cerning the potential polluting activities in a region is available. For exam-
ple, a rationale and accompanying ranking order can be described for Florida.
In the nonpoint source category, emissions should be investigated in the
following ranking order (based on results of a national assessment) unless
special data are available to support a different ranking.
1.
Cropland runoff,
2.
Pasture and rangeland runoff,
3.
Forestland runoff,
169
-------
4.
Livestock feedlots,
5.
Urban runoff, and
6.
Roadway runoff.
For point sources, the results of the national emission assessment (Table
6-17) show that the largest emission category is municipal sewage treatment
effluent. Thus, this evaluation should rank first in order of importance in
the point source studies.
Florida, which has an extremely heavy concentration of phosphate rock
production operations, cqntributes about 78% of the total domestic output of
phosphate rock.27/ A review of national assessment data (Table 6-17) shows
that phosphate rock processing is a major contributor to phosphorus emissions.
Therefore, a study of phosphate rock mining and beneficiation emissions should
rank second.
There are large volume operations for animal feed production in Florida.28/ ,
Also, the national assessment results (Table 6-17) show that this category has
high phosphorus emission factors. Thus, an investigation of phosphorus discharges
from animal feed production should rank third.
There are extensive and large volume production operations for all types
of phosphate fertilizer products in the state.27/ Also, the phosphorus emission
factors for these operations are fairly high, as shown in Table 6-17. According-
ly, an assessment of emissions from the phosphate fertilizer industry in Florida
should rank fourth.
A review of data from the national emission assessment (Table 6-18) indi-
cates that the usage of phosphorus-based water treatment chemicals ranks second
to sewage effluent as a principal point emission source. Therefore, an analysis
of phosphorus discharges from this activity would rank fifth.
Inadvertent sources are shown in Table 6-18 to rank (in magnitude of phos-
phorus emissions) just behind water treatment chemicals on a national basis.
Therefore, an analysis of inadvertent point sources in Florida should rank sixth.
The national point source discharge data (Table 6-18) show that three in-
dustrial categories are all relatively small contributors to phosphorus emis-
sions. These production industries are: (a) phosphorus and derived chemicals;
(b) laundry detergents; and (c) direct acid treatment of metal surfaces. The
largest contributor (to phosphorus emissions) of these three on the national
basis is the first listed category. Therefore, an assessment of the emissions
from production of phosphorus and derived chemicals should rank seventh. For
the remaining two categories, information impacting on their probable impor-
tance in Florida is not readily available. However, since laundry detergents
170
-------
are much more widely utilized than acid for metal treatment, an arbitrary judg-
ment would be to assign a rank of eighth for laundry detergent and ninth for
acid tre~tment operations.
Special Problems in Regional Settings--
There may be a few regions of the United States for which the foregoing
methodology for emission assessment is not completely applicable. The emission
problems in various regions are unique, require evaluation on a case-by-case
basis, and may require some modifications in the suggested quantification pro-
cedures. Thus, certain apparently minor phosphorus emission sources may have
major significance in certain regional settings but would not be a major con-
tributor on a national scale. Examples would be the domestic production and
use of aryl phosphates, treatment of metal surfaces, steel manufacture, etc.
Aryl phosphates are used domestically as fire retardant hydraulic fluids,
plasticizers in flexible plastics, and as lubricant additives. The hydraulic
fluid usage represents the largest contributor of these esters into the environ-
ment. Since reprocessing of waste hydraulic fluid has not been a significant
factor until very recently, large quantities of these fluids were directly in-
troduced into the environment.
The production and use of these compounds represent an extremely small
percentage of total domestic phosphorus consumption. Because of this small con-
sumption rate, the national and regional assessments do not quantify the phos-
phorus discharges from these aryl phosphate manufacture and use operations.
However, in certain metropolitan areas, extensive utilization of hydraulic
equipment which employ and discharge these hydraulic fluids may exist. Thus,
the possibility exists in this case that serious phosphorus pollution could
occur in certain metropolitan areas due to heavy demand and use of aryl phos-
phates. Any assessments of phosphorus emissions for very localized areas must
be aware of apparently minor sources of this type.
DETERGENT PHOSPHATE BANS IN INDIANA AND NEW YORK
Governmental officials responsible for improving water quality, particu-
larly those in the Great Lakes area, are concerned by the slow rate of progress
being made in the improvement of phosphorus control in municipal sewage treatment
and are encouraging legislation to implement detergent phosphorus bans in all
of the states in the Great Lakes Basin. They state that such action would lower
the phosphorus content of municipal effluents until treatment for phosphorus
removal is available.~
The representatives of the detergent industry contend that phosphate com-
pounds are still the most effective and environmentally safe detergent builders.
Industry questions the rationale and statistical evidence that have been pre~
sented that support detergent phosphorus bans. In addition, the attention being
171
-------
given detergent regulation is claimed to be out of proportion with its actual
probable impact on the eutrophication problem.30-32/
Indiana and New York have become the initial testing ground for the effec-
tiveness of a ban on detergent phosphates. Both states implemented detergent
regulations in 1972 which limited the level of total phosphorus in detergent
products to 8.7%. The maximum levels were further reduced to 0.5% in 1973.
The following discussion will present the available data for each state.
Each state will be examined separately on the basis of: (a) surface water
geography, (b) the location and nature of recent water quality problems, and
(c) data illustrating the impact of the phosphate ban.
Indiana
Since the implementation
thoroughly monitored than has
Indiana follows.
of phosphate legislation, Indiana has been more
New York. A discussion of the available data for
Surface Water Geography--
The primary source of surface water in Indiana is rainfall. Approximately
one-third of this precipitation enters the surface drainage systemll/ and is
eventually discharged into the Ohio River (south) and Lake Michigan (north).
Through tributaries, the drainage may also impact on the Mississippi River and
Lake Erie.
Indiana's largest watershed is the Wabash River Basin which drains 67%
of the state and flows south to the Ohio River. The major tributaries of the
Wabash are the east fork and west fork of the White River which run through
the c"entral and south central portions of the state. In addition to the Wabash,
a number of minor streams empty into the Ohio River along Indiana's southern
border.
In the northern portion of the state, the Kankakee River flows west into
an Illinois tributary of the Mississippi River. Lake Michigan receives the waters
of the Grand Calumet and the Little Calumet Rivers, the Indiana Harbor Canal,
Burns Ditch, Trail Creek, and the most northerly of the two St. Joseph rivers.
(There are two completely separate streams which bear the name St. Joseph River
in Indiana.) To the northeast, the other St. Joseph River joins the St. Mary
River and flows eastward through Ohio to Lake Erie via the Maumee River.
Aside from the Lake Michigan shoreline, Indiana does not contain or border
on any natural lakes large enough to be included in the USGS list of U.S. lakes
covering 26 sq km (> 10 sq miles).34/ Similarly, Indiana has only nine state-
owned reservoirs (there are several privately owned empoundments) and only
Monroe has a surface area greater than 26 km (10 sq miles) ( J. M. Minster,
172
-------
personal Communication, Division of Water, Indiana State Department of Natural
Resources, Indianapolis, Indiana, November 1978).
Location and Nature of Water Quality problems--
Water quality problems in Indiana stem primarily from municipal sewage
treatment discharges. Wastes from industry and agriculture also aggravate
conditions in some areas.33/ In addition to phosphorus, the parameters which
command the most interest in municipal effluents are BOD, suspended solids,
and fecal coliform. Additional aspects of municipal, industrial, and/or agri-
cultural waste streams that also require regulation include ammonia, nitrate,
chemical oxygen demand (COD), phenol, cyanidej ,ulfate, sulfide, chloride,
fluoride, zinc, chromium, and oil and grease.~
In recent years, there have been a number of water quality problems along
the Lake Michigan shoreline, especially in the Indiana Ship Canal and Inner
Harbor Basin (the Indiana Harbor Canal in the Grand Calumet River). This locale
must dispose of the wastes of a population approaching one-half million people,
as well as the effluents from one of the most concentrated steel and petroleum
33/
manufacturing complexes in the nation.-- The metropolitan areas included are
East Chicago, Gary, and Hammond.
In this area, municipal and industrial wastestreams are under the surveil-
lance of the International Joint Commission (IJC). As a result, these waste-
streams have been subjected to considerable scrutiny. The following sources
of significant phosphorus discharges have been identified to be C. F. Petro-
leum, Youngstown Sheet and Tube, the sewage treatment plant in East Chicago,
the sewage treatment plant in Gary, and the sewage treatment plant in Hammond.35/
The relative size of these discharges is shown in Table 6-23. The data indicate
that ammost 90% of the point source phosphorus loading in the Indiana Harbor
Canal results from municipal sewage treatment effluents.
No other water quality difficulties in Indiana are of the magnitude of
the problems in the Indiana Harbor Canal; however, the Indiana State Board of
Health identified eight additional regions where significant stream and river
pollution was occurring in 1974 (i.e., generally poor water quality, as indi-
cated by BOD, fecal coliform, nitrate nitrogen, ammonia, and local chemical
wastes--as well as the elevated total phosphorus):
*
The Little Calumet River from Gary to the Illinois state line.
*
Salt Creek below Valparaiso.
*
Trail Creek below Michigan City.
173
-------
TABLE 6-23. . PHOSPHORUS LOADING IN THE INDIANA HARBOR CANAL2,/
kg/day of phosphorus
1975. 1976
East Chicago
C. F. Petroleum
Youngstown Sheet and Tube
East Chicago Sewage Treatment
Plant
12/
75
76
82
'2../
93
Gary
Gary Sewage Treatment Plant
251
538
Hanunond
Hammond Sewage Treatment Plant
£./
667
2,/
Adapted from IJC dat~.-35.36/
12/
Data was not compiled each year for each site.
*
Segments of the Wabash River below Huntington, Logansport,Lafayette,
Clinton, and Terre Haute.
*
The Mississinewa River below Marion.
*
The White River, west fork, from Winchester to below Indianapolis.
*
The Ohio River in the Jeffersonville-Clarksville-New Albany area.
*
33/
The Maumee River below Fort Wayne.--
Each of these areas is located downstream from populated
. treatment discharges so that large amounts of phosphorus
instance along with a variety of other pollutants.
locales and sewage
are present in each
Statewide, municipal treatment wastes are characterized by high levels
of fecal coliform, BOD, COD, and ammonia.
174
-------
Between 1960 and 1975, 295 fish kills occurred in Indiana; of these, 213
involved greater than 600,000 fish. The majority of these incidents took place
in stream or river habitats, and most were the result of elevated BOD's and/or
high ammonia levels downstream from municipal discharges. The common phosphorus
compounds in sewage treatment wastewaters are not toxic and were not implicated
in these problems~
Impact of the Detergent Phosphate Ban--
Two studies have been performed to assess the impact of the Indiana de-
tergent phosphate ban. The first was undertaken by the Indiana State Board of
Health, and the second by Purdue University,. in cooperation with the FMC
Corporation.
Indiana State Board of Health research--In order to quantify the impact
of the detergent phosphate ban, the Indiana State Board of Health has com-
piled pertinent information from data collection procedures that were in ef-
fect before and after the new legislation.~/ These procedures included 24-hr
surveys of municipal sewage treatment plants and testing carried out at water
quality monitoring stations on the major streams. The sewage treatment surveys
included 51, 55, 51, and 42 plants in 1971, 1972, 1973, and 1974, respectively.
There were also variations in the stream monitoring program during the period
of interest. Samples were collected at 58 stations in 1971 and 55 stations in
1972 and 1973 on a biweekly basis. In 1974, 85 stations were sampled monthly.
In addition, 10 intensive segment surveys were initiated in 1974 to further
characterize changes on major rivers.
These programs produced the following data.21I The average content (grams
per capita per day) of phosphorus in raw sewage was reduced by 56% between 1971
and 1974. During the same period, the average content (grams per capita per
day) of phosphorus in the sewage effluents decreased 63%. The difference in
these two figures is due to improved treatment facilities at nine of the 42
plants surveyes in 1974. Stream testing showed a decrease from an average con-
centration of 0.82 mg/liter total phosphorus in 1971 to an average of 0.30 mg/
liter total in 1974. Overall, the State Board of Health estimated the total
reduction in stream phosphorus loading as a result of the ban to be between
25 and 30%. (This estimate has since been challenged. Due to a possible averag-
ing error, the total reduction in phosphorus loading may have been closer to
20% .1!.1 )
Even though Indiana does not have a substantial quantity of lakes or res-
ervoirs, a cursory examination was also given to this portion of Indiana's wa-
ters. The State Board of Health compared their own measurements of total phos-
phorus concentration in Lake Olin, Mississinewa Reservoir, and Long Lake prior
to the ban with those obtained by EPA's National Eutrophication Survey in
August of 1973. Lake Olin, which receives a Small amount of agricultural runoff
175
-------
but no sewage, showed no change in the total phosphorus concentration during
the implementation of the ban. However, both Mississinews Reservoir and Long
Lake do receive treated sewage and/or septic tank seepage. As expected, all
sampling points in these lakes showed a decrease in phosphorus concentration.
A 68% decrease from 1.2 mg/liter total phosphorus to 0.38 mg/liter total phos-
phorus in a 3-year period (1970 to 1973) in the center of the main basin of
Long Lake was the most dramatic reduction noted.33/
The final conclusion drawn by the Indiana State Board of Health was that
the phosphate ban had achieved its intended purpose. However, this conclusion
was immediately followed by a statement emphasizing the importance of con-
tinued improvement in phosphorus removal from sewage treatment discharges and
industrial discharges, as well as minimizing nonpoint phosphorus loading.
The publication of a 1976
Health provided no significant
phorus .37/
305(b) report by the Indiana State Board of
additions pertinent to the control of phos-
Purdue University. FMC Corporation research--A study similar to the
Indiana State Work was carried out during the summer of 1974 by Purdue Uni-
versity and the FMC Corporation.1l! This effort was intended to determine
whether or not the detergent phosphate ban had succeeded in making phosphorus
a growth limiting nutrient in Indiana's waters. Portions of the Wabash and
White River systems were selected for the study due to the large quantity of
Indiana's domestic wastewater discharges that they accept. Alternate biweekly
water samples were collected at the same sites that had been used previously
by the Indiana State Board of Health in the study area.
Chemical analysis provided the concentrations of ortho- and total phos-
phorus present, as well as the concentrations of other nutrients and trace
elements necessary for plant growth. The reported values for total phosphorus
concentration ranged from 0.110 to over 2.00 mg/liter.ll/ The White River
(west fork) contained the highest levels with maximum loading downstream from
the municipal discharges of Winchester, Muncie, Anderson, Indianapolis, and
Martinsville. As indicated in Table 6-24, a much smaller quantity of treated
sewage effluent enters the White River (east fork) or the Wabash River and
consequently relatively lower nutrient levels were found in these rivers.
176
-------
TABLE 6-24.
AVERAGE PHOSPHORUS CONCENTRATIONS AND TREATED
SEWAGE DIS~~RGE RATES IN THE PURDUE/FMC
STUDY AREA-
Avg ortho- Avg total
phosphorus phosphorus Treated sewage
concentration concentration discharge rate
(mg/ i. ) (mg/ i.) (m3/day x 103)
White River, west fork 0.582 0.796 720
Wabash River 0.192 0.423 75.8
~/
31/
Adapted from Etzel, J. E., et a1.- -
None of the laboratory bioassays showed a positive growth response to
phosphorus spiking, indicating the presence of excessive amounts of avail-
able phosphorus in the original samples. A lack of any correlation between
total phosphorus levels and observed fertilities further suggested the ini-
tial phosphorus concentrations in the various samples were all higher than
would be required to limit plant growth.
The determination of the presence of surplus phosphorus in the study
area involved the following genera of algae: Cladophora. Spirogyra.
Rhizoc1onium. and Oedogonium. A criterion of 0.08% extractable phosphorus or
more by weight was used to indicate the presence of surplus phosphorus. As
was the case with total phosphorus concentrations in the river water, the
quantity of extractable phosphorus in the plant tissue paralleled the amount
of upstream treated sewage discharge. The White River (west fork) exhibited
the highest values, ranging from 0.076 to 0.170%. The White River (east fork)
had the lowest values, ranging from 0.075 to 0.094%. The Wabash samples ranged
from 0.099 to 0.137%. According to the Purdue-FMC conclusions, these results
suggest that both the White River (west fork) and the Wabash River contain
algal biomass with a surplus of phosphorus. The White River (east fork) is a
borderline case.
The Purdue-FMC research team concluded that the reduction of stream phos-
phorus concentrations following the ban was insufficient to be of any biologi-
cal significance. After the elimination of detergent phosphates, other sources
of phosphorus in sewage combined with nonpoint sources to maintain sufficient
levels of orthophosphate to create a surplus of this nutrient for plant growth
in Indiana's rivers. Phosphorus was not judged to be a growth limiting factor
in the study area.
177
-------
This conclusion was followed by an editorial statement presenting the
industry-backed alternative to the detergent phosphate ban, namely, improved
sewage treatment including chemical precipitation. Citing extensive use in
Sweden, the study suggested that this technology could provide a proven method
of phosphorus control.
Discussion--
In a discussion of these two studies, limitations inherent in the data
and areas of controversy must be acknowledged. Five areas are presented here.
First, there is a poor data base. Phosphorus levels were not routinely
measured in Indiana prior to the 1970's. As a result, no comparison with past
averages and normal fluctuations is available. This is further complicated by
the predominance of river data in the research. The existing literature which
discusses phosphorus loading and eutrophication has been primarily directed
toward lake and reservoir habitats. This classification system has not been
widely applied to rivers because of the many differences between lake and river
ecosystems. These differences are reflected in the current EPA water quality
criteria that suggest limiting total phosphorus to 25 ~g/lit~r in lakes, but
to 100 ~g/liter in freely flowing rivers~/
Second, the available data describing the impact of the detergent phos-
phate ban in Indiana have been developed and interpreted by parties directly
involved in the outcome of the analysis. There is a notable absence of re-
search activity by an independent third party.
Third, the ultimate value of the detergent phosphate ban in Indiana, on
an overall basis, is undecided. All observers agree that there has been a re-
duction in stream phosphorus concentrations since 1973. However, the importance
of this reduction is dependent on local conditions. In areas where the ~20%
decrease in phosphorus loading has been sufficient to initiate a remedy for
local water quality problems, the ban can be said to have been worthwhile. In
areas where the reduction has not been sufficient to result in water quality
improvements, the value of the ban remains questionable. The Purdue-FMC re-
search contends that the latter situation exists along significant portions of
the Wabash and White rivers.
Fourth, sufficient time may not have elapsed since the implementation of
the phosphorus legislation to allow a good measurement of a nutrient reduction
in Indiana's waters. The exchange and recycling of phosphorus among plant and
animal tissues, water soluble chemical species, and sediments makes the deple-
tion of excess phosphorus in aquatic ecosystems a gradual process. Remedial
action which lowers nutrient loading on a lake or river habitat should not be
expected to yield immediate results.
178
-------
Fifth, the economic impact of phosphate legislation is another source of
contention. Those in favor of banning detergent phosphates claim substantial
savings due to lowered demand for sewage treatment chemicals and sludge dis-
posal. (Associated reductions in environmental insult via by-products of chem-
ical treatment and sewage sludge incineration are also claimed.)12! Ban oppo-
nents suggest that consumers in ban areas incur substantial dollar losses
(- $5.00 per household per year according to Proctor and Gamble) due to increased
rates of detergent usage with nonphosphate products, water 'softening costs, and
repair cosilifor washing machines engineered to function with phosphate treated
washwater.
New York
Compared with Indiana, New York contains and borders on many more lakes and
at least an equal number of rivers. This abundance of lake habitat places New
York in greater danger of eutrophication problems than that present in Indiana.
Surface Water Geography--
In total, there are around 8,000 lakes and ponds in New York, and 10 of
these are large enough to appear on the USGS listing of lakes covering 26 sq
kIn or more (> 10 sq miles). New York has 121 kIn (75 miles) of shoreline on Lake
Erie and greater than 320 kIn (200 miles) of shoreline on Lake Ontario. After
Lakes Ontario and Erie, the next largest lake is Lake Champlain which covers
1,270 sq kIn (490 sq miles) along the eastern border. Lake Oneida, the largest
lake completely within New York's borders, covers 207 sq kIn (80 sq miles). In
addition, New York, has 72 reservoirs, the larges~f which is the Sacandaga
River Reservoir covering 108 sq kIn (42 sq miles).
New York contains or borders on numerous mnall streams and a few larger
rivers including:
*
The Niagara River, flowing from Lake Erie to Lake Ontario.
*
The St. Lawrence River, flowing from Lake Ontario to the Canadian
border.
*
The Hudson River, flowing south near the eastern border to New York
City and the Atlantic Ocean.
*
The Delaware River, draining southeastern New York and flowing south
to become the Pennsylvania-New Jersey border.
*
The Allegheny River, draining western New York and flowing southwest
into Pennsylvania.
179
-------
The Location and Nature of Recent Water Quality Problems--
The most detailed examination of phosphorus related water quality problems
in New York is provided by IJC publications.35.36/ Tabulations of nutrient load-
ing from various sources along the Lake Ontario and Lake Erie shorelines are
included in these reports. Problem areas are identified and the progress of
remedial programs is noted on a yearly basis.
A second source of data illustrating nutrient loading problems in New York
is the work of the National Eutrophication Survey. The lake portion of this
research effort provides an excellent statewide study of the trophic condition
of New Y?rk lakes prior to the detergent phosphate ban.
IJC data--The work of the IJC has been oriented toward the identification
and solution of all types of water quality problems in the Canadian boundary
waters. Past examinations have established the need for improved phosphorus
control, particularly in metropolitan areas. The flow of Lakes Superior,
Michigan, and Huron into Lake Erie has placed a heavy nutrient load on Lake
Erie and, to a lesser extent, also on Lake Ontario. Phosphorus has been singled
out as the most easily controlled causitive agent, and remedial programs are
under way.35.36/
The thrust of these IJC programs has centered on improved sewage treat-
ment with an effluent goal of 1.0 mg/liter total phosphorus. The performance
of large plants in highly populated areas has been of primary interest. No con-
centrated effort has been made to quantify the impact of detergent phosphate
bans in the affected state and metropolitan regions. Nevertheless, the data
collection procedures under way do serve to identify the major point sources
of phosphorus discharges (> 95% are municipal sewage treatment facilities).
New York is responsible for only a small fraction of Lake Erie's diffi-
culties, but New York effluents do impact heavily on Lake Ontario. A list of
these municipal sources, including all of those discharging> 50 kg/day phos-
phorus during either 1975 or 1976, is given in Table 6-25. This listing of
16 plants provides over 80% of the total point source phosphorus loading on
the Lake Ontario-St. Lawrence River Basin by New York State.
National Eutrophication survey--The National Eutrophication Survey (NES)
selected 30 lakes and reservoirs in New York for their 1972 sampling. This
coincided with the period immediately following the initial phosphate legisla-
tion limiting total detergent phosphorus to 8.7% and precedes the enactment
of the phosphate ban. The choice of lakes for the study provided a representativ~
cross-section of natural and man~ade lakes. Data describing 23 of the subject
lakes and reservoirs were published in 1975 and provide the following informa-
tion.40j
180
J-
-------
TABLE 6-25. MAJOR NEW YORK SEWAGE TREATMENT PLANT DISCHARGES
INTO LAKE ONTARIO DURING 1975 AND 1976!/
Amherst
Amherst S.D. No. 16
Auburn
Brighton (Allen Creek)
Buffalo
Canton
Chili
Ithaca
Lowville
Monroe County. (N.W. Quad.)
Niagara Falls
North Tonawanda
Rochester
Syracuse
Tonawanda S.D. No.2
Watertown
Flow
(103 m3/day)
1975 1976
29.3
28.9
38
21
650
4.6
40.3
23.1
3.2
29.3
263
26.6
262
270
48.3
23.9
27.4
33.4
42.4
22.7
661
7.5
43.2
25.3
4.05
38.3
201
28.5
284
296
50.2
38.5
Avg annual P
concentration
(mg/1,)
1975 1976
1.0
4.2
1
2.5
3.3
1.9
3.8
1.0
2.5
2.0
2.3
5.4
9.0
4.9
3.9
2.5
2.6
2.3
8.3
3.4
3.4
15.8
1.6
2.1
1.4
1.9
5.3
1.0
Total P
loading
(kg/day)
1975 1976
29
121
36
59
1,650
13
132
64
6
109
256
56
522
610
259
213
134
130
106
48
1,520
62.2
147
87.3
63.9
61.2
60
398
565
265
38.7
~/ Adapted from Reference 35. Measurements having greater than three signifi-
cant figures have been rounded to 3.
181
-------
Of the 23 lakes, 14 were found to be eutrophic. Of these 14, 11 receive
sewage treatment wastes either from municipal facilities and/or septic tanks
within 91.5 m (100 yards) of the shoreline. The lakes were classified on the
basis of physical and chemical characteristics, biological characteristics,
nutrient loading, and nutrient export via outlet streams. A summary of per-
tinent data is presented in Table 6-26.
The Impact of the Detergent Phosphate Ban--
The impact of the detergent phosphate ban in New York remains undecided.
No large scale research effort has specifically addressed this question. The
best data on nutrient loading in New York are provided by IJC and NES publi-
cations, but neither group has attempted to assess the effect of the legisla-
tion. .
The New York State Department of Environmental Conservation records the
phosphorus content of municipal effluents and effluents from all other point
sources having a phosphorus limitation in their discharge permit. Recently,
this inventory has been computerized which will facilitate examination of the
data. To date, no attempt has been made to demonstrate the impact of the phos-
phate legislation using this information.
Discussion--
Shortcomings present in the New York data are very similar to those
described for Indiana in four areas. First, normal averages and fluctuations.
of phosphorus levels in New York's freshwater habitats prior to the 1970's are
not available. Second, the ultimate value of the detergent phosphate ban in
New York is undecided. Less documentation showing phosphorus loading reductions
due to the ban is available in New York than in Indiana. Third, due to the re-
cycling of phosphorus that is characteristic of aquatic habitats, water quality
improvements may not be observed for many years--even if legislation is achiev-
ing a significant nutrient reduction. Fourth, the economic impact of the legis-
lation remains a question.
Unlike Indiana, New York does contain a large number of sizable lakes
and reservoirs. As shown by Table 6-26, a significant group of these were
found to be eutrophic by the NES sampling program prior to the 1973 legisla-
tion. The quantity of total phosphorus loading stemming from human sewage
was recorded in each case. Follow-up studies on these lakes would provide
valuable data in assessing the impact of the detergent phosphate ban.
182
-------
TAJll.E 6-26. 19"J2 NES LAKE AND RESERVOIR DATA FOR NEW YONK STATe!/ '
l.imiting Municipal and Approximate net lake
Surface Mean Median Me.an chlot'u- nulri~nt s~,ptic tank Nonp.:li1\t surf ace areac~ loading
Trophic area depth tOld 1 I' phyll b ("pring) P loadi ng P loading rat~-
conditio"'!!/ (1an2 ) (01) (018/ t) (1'1511) P or N (kg/yr) (kg/yr) (k~llan 1 yr)
Black L. E ]].8 0.010 )'J. 1 N (j 54,200 .In
Cannonsville R. E 19.4 11,1.2 0.040 29.9 I' 0 82,800 J.lf:-!0
CdSSadCtS.1 I.. E 0.8 11.026 9.7 P 459 222 501
Chautauqua L. E 57.2 0.9 0.028 U.') N 3.42U 7.1fJO Net loss
Conesus L. E 12.9 8.9 0.020 9.9 N 336 4.590 218
Cross L. E 8.8 5.5 0.076 19.5 N 59.100 236.000 7.590
Goodyear L. E 1.5 (J.U26 9.6 P 3.720 18.400 4.040
L. Huntln.gtoll E 0.:1 0.015 6.'.. P 5 32 5 \
Lower St. Regl s L. E 1.9 5.1 0.017 7.9 P 104 658 43.8
Ottt:'r L. E 1.1 0.043 \3.:1 P 0 77 Net loss
Round L. E 1..1 0.010 28.3 N 1.010 5.750 92u
Saratogd L. E 1t..3 7.9 0.025 11.8 P l'J ".100 12.800 853
Swan L. E 1.3 0.042 9.5 N 368 1.020 362
Swing! ng Bridge R. E ').5 13.4 0.057 28.7 r 19.700 4.800 4.140
I-'
00 5
W Carry Fall" R. M 20.1 5.4 0.010 .1.1 P 18.600 198
Cayuga J.. M 172.0 54.0 0.014 3.2 P 37.400 46 . 700 254
l.ong L. H 16.0 O.OOR j.J P 91 7.350 Net loss
Owasco L. ~I 26.7 29..1 0.0\)9 8.5 P
Sacandaga R.. M 122.0 7.6 0.009 1,.8 P 717 21.200 47.5
SElleca L. 11 17'J.O 88.7 0.010 b. I P 48.500 18.500 .1Gb
Canadiagua L. 0 43.0 39.0 0.009 4.3 P 2,780 3,260 91.7
Keuka L. I) 47.4 22.6 0.008 5.7 P 744 4,200 54.7
Schroon L. I) It.. 7 14.3 0.004 2.1 P 195 6,340 Net loss
.!!I Adapted (rem Reference 40. Measurem~nts having gr~ater than three signi f lcant fl~!urcs h.Jv,,: Le..:n r(lulided [0 J.
.!!I E - ~utrophlci H - mesotropldc; and I) - ol1gotr.:lphlc.
£/
TOlal P loadln~ minus tocal P dischargi:d from Ot'!!" l.!t Sl rcitUiS per ~urfac(~ ari'a
phosphorus luadiu~ used in calculat in~ these value~ do 11(}L iucLudf.. 0111 al Llu-'
on th~ respect ivf'. shorelines.
pt:r year.
SNnC of t.he dJt.:l for
point "iOUl'ces
-------
REFERENCES--SECTION 6
1.
McElroy, A. D., et ale National Assessment of Water pollution from
Nonpoint Sources. Draft of Final Report, EPA Contract No. 68-01-2293
U.S. Environmental Protection Agency, Washington, D.C., 1975. pp. 1-
8, 18-31, and appendix.
2.
Wischmeier, W. H., and D. D.
Losses from Cropland East of
book 282, U.S. Department of
Washington, D.C.
Smith. Predicting Rainfall--Erosion
the Rocky Mountains. Agriculture Hand-
Agriculture, Agriculture Research,
3.
Parker, C. A., et ale Fertilizers and Lime in the
U.S. Department of Agriculture Misc. Pub. No. 486
D.C.
United States.
(1946), Washington,
4.
Murphy, T. J. Sources of Phosphorus Inputs from the Atmosphere and
Their Significance to Oligotrophic Lakes. Research Report No. 92,
University of Illinois Water Resources Center, Urbana, Illinois,
1974. pp. 31-34, 43-45.
5.
Anderson, D. National Emissions Inventory of Sources and Emissions
of Phosphorus. EPA 450/3-74/013 (PB 231 670), U.S. Environmental Pro-
tection Agency, Research Triangle Park, North Carolina, 1973. pp. 8-
32,37-40.
6.
International Joint Commission. International Reference Group on
Great Lakes Pollution for Land Use Activities (PLUARG). Environ-
mental Management Strategy for the Great Lakes System, Windsor,
Ontario, July 1978. p. 50.
7.
Kosakowski, M. W. Development Document for Interim Final Effluent Lim-
itation Guidelines and New Source Performance Standards for the Min-
erals for the Chemical and Fertilizer Industries, Volume II, Mineral
Mining and Processing Industry, Point Source Category. EPA 440/1-75/
059b, Group II, U.S. Environmental Protection Agency, Washington, D.C.,
October 1975. pp. 103-110.
184
-------
8.
Standard Industrial Classification Manual. Statistical Policy Division,
. Executive Office of the President, Office of Management and Budget.
U.S. Government Printing Office, Washington, D.C., 1972. pp. 9-13,
42, 63, 64, 68, 113, 118, 122-125.
9.
St6wasser, W. F. Commodity Data Summaries. U.S. Department of the In-
terior, Bureau of Mines, Washington, D.C., 1977. pp. 124-125.
10.
Martin, E. E. Development Document for Effluent Limitation Guidelines
and New Source Performance Standards for the Basic Fertilizer Ch~mi-
cals Segment of the Fertilizer Manufacturing Point Source Category.
EPA 440/1-74/01la (PB 238652), U.S. Environmental Protection Agency,
Washington, D.C., March 1974. pp. 33-34, 41-51.
H.
Shreve, R. N., and J. A. Brink, Jr. Chemical
ed. McGraw-Hill Book Company, New York City,
261.
Process Industries, 4th
New York, 1977. pp. 244-
12.
Lowenheim, F. A., and M. K. Moran. Faith, Keyes, and Clark's
trial Chemicals, 4th ed. John Wiley and Sons, Inc., New York
New york, 1975. pp. 628-657.
Indus-
City,
13.
Rawlings, G. D., E. A. Mullen, and J. M. Nyers. Source Assessment:
Phosphate Fertilizer Industry; I - Phosphoric Acid and Superphosphoric
Acid. EPA600/2-77/107, U.S'. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1977. (Preliminary report not for dis-
tribution.) pp. 36-42, 63.
14.
Nyers, J. M., and G. D. Rawlings. Source Assessment: Phosphate Fer-
tilizer Industry; II - Normal and Triple Superphosphate Fertilizer.
EPA 600/2-77/107, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1977. (Preliminary report not for
distribution.) pp. 23-30.
15.
Bixby, D. W., et ale Phosphate Fertilizers--Properties and Processes.
Bulletin No.8 (revised), The Sulphur Institute, Washington, D.C.,
1966. p. 70.
16.
Kirk, R. E., and D. F. Othmer. Encyclopedia
2nd ed~, Volume 9. Interscience Publishers,
1966. pp. 105-108.
of Chemical Technology,
New York City, New York,
17.
Moscowitz, C. M., and G. D. Rawlings. Source Assessment: Phosphate
Fertilizer Industry; III - Granular Ammonium Phosphate Fertilizer.
EPA 600/2-77/107, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1977. (Preliminary report not for
distribution.) pp. 26-29, 63-64, 76-79.
185
-------
. 26.
18.
Rhines, C. E. Development Document for Effluent Limitation Guidelines
and New Source Performance Standards for the Other Nonfertilizer phos-
phate Chemicals Segment of the Phosphate Manufacturing Point Source
Category. EPA 440/1-75/043, Group I; phase II, U.S. Environmental Pro-
tection Agency, Washington, D.C., 1976. pp. 23-30.
19.
Martin, E. E. Development Document for Effluent Limitation Guidelines
and New Source Performance Standards for the Phosphorus Derived Chemi-
cals Segment of the Phosphate Manufacturing Point Source Category.
EPA 440/1-74/006a, U.S. Environmental Protection Agency, Washington,
D.C., 1974. pp. 15-40, 45-66.
20.
U.S. Environmental Protection Agency. Draft Supplement to Development
Document for Effluent Limitations Guidelines and New Source Performance
Standards for the Phosphorus Derived Chemicals Segment of the Phosphate
Manufacturing Point Source Category. EPA Contract No. 68-01-3289, Of-
fice of Water and Hazardous Materials, Washington, D.C., 1977. pp.
1-5.
21.
Sawyer, C. N., and P. L. McCarty. Chemistry for Sanitary Engineers.
McGraw-Hill Book Company, New York,City, New York, 1967. p. 466.
22.
Gregg, R. T. Development Document for Proposed Effluent Limitation
Guidelines and New Source Performance Standards for the Soap and De-
tergent Manufacturing Point Source Category, EPA 440/1-74/18, U.S.
Environmental Protection Agency, Washington, D.C., 1973. pp. 1, 17,
77.
23.
Betz Laboratories, Inc. Handbook of Industrial Water Conditioning,
2nd ed. Trevese, Pennsylvania, 1976. pp. 192-201.
24.
National Commission on Water Quatliy. Staff Draft Report, Washington,
D.C., November 1975. p. 11-43.
25.
Municipal Construction Division of U.S. Environmental Protection
Agency (EPA 430/9-76-010, 430/9-76-011, and 430/9-76-012), Cost
Estimates for Construction of Publicly-owned Wastewater Treatment
Facilities--1976 Needs Survey, Washington, D.C., 1976.
U.S. Environmental Protection Agency, Office of Technology Transfer.
Process Design Manual for Phosphorus Removal, EPA 625/1-76-00/001,
Cincinnati, Ohio, April 1976.
27.
Stanford Research Institute. 1973-1977 Directory of Chemical Producers.
Chemical Information Services, MenloPark,California.
186
-------
39.
28.
MRI interpretation of industrial contacts and Chemical
book. Calcium Phosphates. Stanford Research Institute,
760.600lF to K.
Economics Hand-
October 1977.
29.
Alexander, G. R., Jr., and D. A. Wallgren. Detergent Phosphate Ban--
position Paper Prepared by the Region V Phosphorus Committee. EPA
905/2-77/003, Chicago, Illinois, 1977. 62 pp.
30..
A compilation of information by industry representatives presented
to the members of the House Senate Conference Committee on the Clean
Water Act of 1977, August 1977. 35 pp.
31.
Etzel, J. E., J. M. Bell,
gent Phosphate Ban Yields
and III. Water and Sewage
and November 1975.
E. G. Lindermann, and C. J. Lancelot. Deter-
Little Phosphates Reduction. Parts I, II,
Works, Chicago, Illinois, September, October,
32.
Kimerle, R. A., K. C. Plunkert, and L. C. Scharpf, Jr. Examination
of the Relationship between Phosphorus Loading and Water Quality Param-
eters for. the Great Lakes. The Monsanto Company, St. Louis, Missouri,
1977. 19 pp.
33.
Indiana State Board of Health, Water Pollution Control Division. 305
(b) Report, Indianapolis, Indiana, 1975. 380 pp.
34.
Todd, D. K., ed. The Water Encyclopedia. Water Information Center,
Port Washington, New York, 1970. pp. 124, 312-315, 407-410.
35.
International Joint Commission. Great Lakes Water Quality 1976, Ap-
pendix C. Remedial Programs Subcommittee Report, Windsor, Ontario,
1976.
36.
International Joint Commission. Great Lakes Water Quality 1975, Ap-
pendix C. Remedial Programs Subcommittee Report, Windsor, Ontario,
1975.
37.
Indiana State Board of Health, Water Pollution Control Division, 305
(b) Report, Indianapolis, Indiana, 1976. 404 pp.
38.
Office of Water Planning and Standards. Quality Criteria for Water.
PB 363 943, U.S. Environmental Protection Agency, Washington, D.C.,
July 1976. pp. 352~360.
Hall, R. E., Manager, Product Safety and Regulatory Services, Proctor
and Gamble. Testimony before Ohio House of Representatives, Subcommit-
tee on Energy and Environment. January 11, 1978.
187
-------
40.
Corvallis Environmental Research Laboratory, Corvallis, Oregon, and
Environmental Monitoring and Support Laboratory, Las Vegas, Nevada.
A compendium of lake and reservoir data collected by the National
Eutrophication Survey in the Northeast and North-Central United States.
Working Paper No. 474, November 1975. pp. 136-158.
188
-------
APPENDIX A
CONVERSION FACTORS USED IN PHOSPHORUS TERMINOLOGY*
*
Developed by MRI from data in various technical publications.
189
-------
To convert from To Multiply by
% BPL!! %P 0.1997
% BPL % P205 0.4576
% P205 % P 0.4364
% P205 % BPI. 2.1853
% P % P205 2.2914
% P % BPL 5.0073
% P205 % H3P04 1.381
% P % H3P04 3.164
% H3P04 % P 0.316
% H3P04 % P205 0.724
~! BPL = bone phosphate of lime,
phag e .
i.e.,
tricalciwn phos-
190
-------
APPENDIX B
DESCRIPTIONS OF TYPICAL METHODOLOGY USED TO CALCULATE
THE ESTIMATED TOTAL PHOSPHORUS EMISSIONS FROM
INDUSTRIAL POINT SOURCES
191
-------
This appendix provides a description of typical calculation methods used
to estimate the total phosphorus emissions from all of the industrial point
sources presented in this report.
In all emission estimates discussed in this report, the term phosphorus
refers to the total phosphorus content unless otherwise noted. All data on
quantification of phosphorus sources are presented in terms of total phos-
phorus (i.e., kilograms (kg) of total phosphorus per metric ton (MT) of product,
or metric tons of total phosphorus per year). One metric ton is equivalent to
1,000 kg or 2,205 lb. Much of the phosphorus data reported in the literature
is in terms of phosphorus pentoxide (P205) content. The percent P205 can be
converted to percent total phosphorus (p) by multiplying by 0.4364. As a mat-
ter of convenience in explaining the methodology, a few of the figures and tables
shown in the body of this report are also shown in this appendix.
EXAMPLE A: ESTIMATES OF PHOSPHORUS EMISSIONS FROM MINING AND BENEFICIATION
OF PHOSPHATE ROCK IN THE EASTERN UNITED STATES
The methodology used in this example is typical of that used for all
studies in this report on phosphorus rock mining.
A representative flow diagram describing phosphate mining and processing
for eastern states is shown in Figure B-1. A discussion of the phosphorus emis-
sion estimates for eastern states is provided in the following paragraphs.
Effluent Wastewater
The treatment of process wastewater streams consists basically of gravity
settling through extensive use of ponds.
192
-------
Air Emission
Ni I for Florida
0.03 kg P for other Eastern States
Screen
and
Wash
Mine
......
\0
W
r-
I I
IB:
I I
L- Screen J
Conditioner.
Flotation
I (Primary) I
I I
I I
L______-.t_-----------
Slimes
Removal
Figure B-l.
Legend:
. Alternate Route No.1
- - - - AI ternate Route No.2
Recycle
Water
Water
De-Oil
Conditioner.
Flotation
( Se co ndary )
I
I
I
I
- -_J
T ai Ii ngs Disposal Pond
Total Phosphorus loss per MT Beneficiated Ore
Air = 0.09 kg P/MT (Florida)
= O. 12 kg P/MT (Other Eastern States)
Water = 0.005 kg P/MT
Intermittent
Wastewater
Discharge
0.005 kg P on
Annual Basis
r Air Emission,
Ore Handling
and Dryi ng
Atm. 0.09 kg P
Vent
Filter
and/or
Dryer
Product
1 MT
.. Recycled Water
to Process
Flow diagram for phosphate ndning and processing--eastern states.
-------
An analysis of 18 eastern facilities for phosphate ore mining (located
in Florida, Tennessee, and North Carolina) showed that the average discharge
of total phosphorus in the form of phosphate rock amounts to 0.047 kg p/MT
of beneficiated ore.
Mr. Elwood E. Martin of the Inorganic Chemical Branch, Effluent Guide-
lines Division of the U.S. Environmental Protection Agency (EPA) has indicated
that approximately one-half of the Florida phosphate fertilizer producers have
gypsum pond discharges of wastewater for a total of about 2.5 months out of
every year and that, for all practical purposes, this estimate may be extended
to the entire United States (Martin, E. E., EPA, Effluent Guidelines Divi-
sion, Washington, D.C., personal communication, January 1978). On this basis,
the phosphorus discharge in plant wastewater can be estimated as follows:
0.047 x 0.5 x 2.5/12, or about 0.005 kg P/MT of beneficiated ore.
Atmospheric Emissions
Air emissions occurring during mining and beneficiation were estimated
on the basis of emission data presented in Table B-1.
Mining--
Wet mining operations utilized for Florida land pebble phosphate rock
produce essentially no particulate or phorphorus emissions. Therefore, phos-
phorus air emissions from the activity are considered to be negligible.
During open-pit mining of hard rock phosphate in Tennessee and North
Carolina, the ore mining, loading, and hauling result in air emissions of
. .
small amounts of phosphate rock particulates. This air emission was estimated
as follows based on the assumption that the P205 content of the particles
194
-------
TABt£ B-1.
SOllRI:ES ANn E:nlllA"rt:s Ill' I'II051'IIORIIS-COtlrAINING AIR EMISSIONS
FOR t:ASTERN PIIOSI'IIATt: ROCK MINING AND
Bt:NEFfGlATlON
production activity
IJllcUIII..-O II ell
partIculate
eml s5I un
factor
(kg/m)
:.. I'P5
in -
ClM ss! OIlS
Estimated
lev..1 of
emIssIon
control
Total phosphorus
emissi.oll:i--
alter controls
(kg pitH product)
COfIIRents
(%)
Eastern producers
Hining
ore hand ling
Drying
0.2:>
0.5
7.5
26
30
JO
o
50
94
0.03
0.03
0.06
Not applIcable to Florida
wct-mining operations
I-"
\0
VI
Tota 1
0.12
-------
emitted to the air is the same as the average PZ05 content of the phosphate
ore.
The uncontrolled particulate erndssion factor is 0.Z5 kg/MT of bene-
ficiated ore, the reported PZ05 content in the ore is Z6%, and there is no
emission control. Thus, the phosphorus emission is estimated to be:
0.Z5 x 0.Z6 x 0.4364, or about 0.03 kg P/MT of beneficiated ore.
Beneficiation--
Phosphorus air emissions which occur during the phosphate ore beneficia-
tion process are estimated as follows:
For ore handling, the particulate emission factor is 0.5 kg/MT of bene-
ficiated ore. The PZ05 content in the ore is 3~1o (during beneficiation, some
upgrading of the ore occurs by screening operations, etc.). The level of emis-
sion control is 5~1o. The estimated emission is equal to:
0.5 x 0.3 x 0.5 x
0.4364, or about 0.03 kg P/MT of beneficiated ore product.
For drying of the phosphate rock concentrate, the reported uncontrolled
emission is 7.5 kg of particulate per metric ton of beneficiated ore, the
particulate contains 30% PZ05, and the emission control is 94%. Therefore,
the estimated emission is equal to:
7.5 x 0.3 x (100% - 94%)
x
0.4364,
or .
about 0.06 kg P/MT of beneficiated ore.
Summary of Phosphorus Losses to the Environment
For estimating purposes, it was assumed that the ore mining and produc-
tion patterns for 1978 were the same as those reported for 1975:
Florida,
78%; North Carolina, 5%; Tennessee, 5%; and western states, lZ%. Thus, the
eastern operations accounted for 88% of total beneficiated ore production.
196
-------
."
A summary of phosphorus emissions from eastern phosphate mining and
beneficiation (basis 1 MT of beneficiated ore, see Table B-1) follows:
Total atmospheric losses for Florida
= 0.03 + 0.06
= 0.09 kg P/MT
Total atmospheric losses for all other eastern states
= 0.03 + 0.03 + 0.06
= 0.12 kg P/MT
The wei(g~::: averag)e at(m~::~eriC 10)SS
= 0:88 x 0.09 + 0:88 x 0.12
for all eastern states is:
= 0.080 + 0.014
= 0.094 kg P/MT
Total wastewater losses for all eastern states
= 0.005 kg P/MT
National Emissions for Minin
and Beneficiation of phos hate Rock
In 1976, the total U.S. marketable production of beneficiated phosphate
rock was reported to be 44,452,000 MT (Table 6-17, p. 57). Based on informa-
tion in the literature, production is estimated to increase to 56,245,200 MT
in 1980. Assuming a uniform growth rate from 1976 to 1980, the production
level for 1978 can be estimated to be 50,348,000 MT of beneficiated phosphate
rock.
197
-------
The phosphorus emission loss in wastewater for all eastern operations can
be estimated as:
0.88 x 50,348,000 x 0.005/1,000, or about 220 MT phosphorus.
There are no significant air emissions from Florida wet mining operations.
Open-jet mining in North Carolina and Tennessee does account for phosphorus
emissions. Also, ore handling and drying operations for all eastern ores con-
tribute to phosphorus air emissions. The weighted air emissions factor for all
eastern operations is 0.094 kg P/MT beneficiated ore. The estimated overall
phosphorus air emission for all eastern states is:
44,306 x 0.094~ 4,165 MT
phosphorus.
EXAMPLE B: ESTIMATES OF PHOSPHORUS EMISSIONS FROM PRODUCTION OF NORMAL
SUPERPHOSPHATE FERTILIZER
The methodology described in the following example for normal superphos-
phate (NSP) fertilizer is representative of the estimating procedures used
for the other phosphate fertilizer and phosphate animal feed products dis-
cussed in this report. The technologies which are represented by this example
include wet-process phosphoric acid production, superphosphoric acid produc-
tion, triple superphosphate, ammonium phosphates, animal food calcium phosphate,
and defluorinated phosphate rock.
A representative process flow diagram for production of NSP is shown in
Figure B-2.
Material Balance Data
The weight ratio of phosphate rock to NSP product is 0.605 to 1, when
the feed material contains 34.3% P205 (or 14.98% phosphorus). Thus, 1 MT of
product is equivalent to 0.605 MT of phosphate rock. The average P205 content
198
-------
t-'
-.D
-.D
Gas
Containment
Enclosure
. (Dotted Li nes)
Air Emission
O. 1 kg P
I
.~
'-
Unloading,
Grinding,
Feedi ng
Ground Phosphate Rock
605 kg
90.6 kg P
I Mixer
Exhaust Gas
Cone~-
Sulfuric Acid!
Water
Conveyor
Curing
Bui Iding
Phosphorus Values per MT Product
Input P = 90.6 kg P
Output P = 82.9 kg P
Atm Losses = 0.47 kg P
Water Losses = 0.007 kg P
Recycled Water
O. 15 kg P
Gas Discharged to Atm
Scrubbe r
Exhaus t
Raw
Wastewater
G 940 to 1040 liters
as
Holding Pond
Treatment Unit
Pulverizer
I ntermi ttent
Wastewater
Di scharge
0.007kg P on
Annual Basis
Screen ing
Air
Emission
0.22 kg P
Bagging
Product, 1 MT
82.9 kgP
Figure B-2.
Flow diagram for production of normal superphosphate.
-------
in the NSP product was assumed to be 19% (or 8.29% phosphorus). One metric
ton of product contains:
1,000 x 0.0829, or 82.9 kg phosphorus.
Wastewater Effluent
Current information on wastewater containment practices indicates that
. only 4% of the domestic NSP plants discharge wastewater and that practically
all discharging plants treat their wastewater to remove most of the contained
phosphorus.
It was assumed in this report that a holding and treatment pond is pro-
vided for each fertilizer plant operation and that wastewater is impounded and
reciruclated in the plant. Also, it was assumed that the phosphorus content in
treated effluent from NSP plants corresponds to the EPA effluent limitation
guidelines for best practicable control technology currently available (i.e.,
a maximum average discharge for 10 or more consecutive days of 35 mg of total
phosphorus per liter of wastewater). It was further assumed that for those
plants which discharge effluent, the total discharge period each year would
be 2.5 months (Martin, E. E., EPA, Effluent Guidelines Division, Washington,
D.C., personal communication, January 1978).
The range of discharge rates of contaminated wastewater from the process
is 940 to 1,040 liters/MT of NSP product. An average flow rate of 990 liters/
MT is assumed. The estimated discharge of phosphorus in wastewater to the
environment is calculated as follows:
990 x 0.035/1,000 ~ 0.035 kg P/MT of
NSP product. For a 2.5 month period of discharge each year, the annual phos-
phorus release in wastewater would be equal to:
2.5/12 x 0.035, or 0.007 kg
P/MT of NSP product.
200
-------
Atmospheric Emissions
The air emission points in NSP production are the ore grinding operation,
phosphate rock unloading and feeding, the mixer, the curing building, product
pulverizing, and bagging losses. Sources and estimates of phosphorus-containing
air emissions for NSP production are shown in Table B-2. The estimating proce-
dures used are described below.
Grinding of Phosphate Rock--
The uncontrolled particulate emission is reported to be 3 kg/MT of NSP
product. Also, the particulate contains 34% P20S' and the level of emission
control is 80%. The emission is calculated to be:
3 x 0.34 x 0.4364 x (100%
80"1..) rv 0.09 kg P/MT of NSP.
Material Hand1ing--
The average controlled emission factor for unloading phosphate rock is
0.28 g of particulate per kilogram of P20S contained in product (NSP). The
phosphate rock contains 34% P20S' and the product contains 19% P20S. The un-
loading emission is calculated as:
0.28/1,000 x (1,000 x 0.19) x 0.34 x
0.4364 rv 0.008 kg P/MT of NSP.
For phosphate rock feeding, the controlled emission is reported to be
o.OSS g of particulate per kilogram of P20S in NSP. The feeding emission is
calculated as:
O.OSS/l,OOO x (1,000 x 0.19) x 0.34 x 0.4364 = 0.0016 kg P/MT
of NSP.
Mixer and Den--
A reported controlled emission factor for this source is 0.26 g of par-
ticu1ate per kilogram of P20S in NSP product. Thus, the phosphorus emission
201
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TABlE B-2. SlJUItCES ANII .,STHl'\TES Of Plh)SI'IiOItUS-CONTAfNING AIR ENiSSIONS
FOI! NOlmAI. SIJI'EIH'IIOSI'IIATE PIU)(J\JCTION
Production act ivity
UnculIl..-.)lled
p<.orticul..te
cIIlJS:iJoU
facLoL'
(lq;hrr product)
GOllt L'vll cd
ClUi ss iou t~H;lor
(g of paL'Liculate
per kg 1'205 in
p,"oduct)
E,;tllII...tcd
level of
elllis,;lon
control
("I-)
% 1'205
in
emissions
Tot,,\
P emis,;ions
after cOlltrol,;
(kg P/Mf product)
N
o
N
Grinding I'hospha te rock J NA IiU 34 0.090
Haterial handling:
Phosphate rock unload- NA 0.2/3 NA 34 0.00/3
ing
lJho::iplaatc nIck feeding NA 0.055 riA 3l, 0.002
Mixer alld den NA LI.:!6 NA \<) 0.004
Curing Luildillg NA 3.6 IIA 19 0.057
I' L"oduc l grinding U.25 NA 1i0 !!-/ 0.02
Product ~crccoiHg 1 NA /35 :l1 0.07
PL'o,luCl Lagging or Lulk O.5!?/ NA Y 311 0.22
10..dlng
TOla I 0.47
}!/
E",I""ioll I<1CI.,,1' incillde" '/.. 1':/>5'
.!!I
ElllitJ~jou Lh:LoJ."
alLcJ C(JlIl&III.
NA .., Not <.ov.lilal"".
-------
is estimated as:
0.26/1,000 x (1,000 x 0.19) x 0.19 x 0.4364
=
0.004 kg P/MT of
N~.
Curing Bui1ding--
The controlled emission factor is 3.6 g of particulate per kilogram of
P205 in product. The phosphorus emission is estimated as:
3.6/1,000 x (1,000 x
0.19) x 0.19 x 0.4364 = 0.057 kg P/MT of NSP.
Product Grinding--
The uncontrolled particulate emission factor is 0.25 kg/MT of NSP, and
the level of emission control is 80%. On this basis, the emission is estimated
as:
0.25 x (10~1. - 80%) x 0.4364 = 0.02 kg P/MT of NSP.
Product Screening--
The estimated uncontrolled emission factor is 1 kg of particulate per
metric ton of NSP, and the level of emission control is 85%. Thus, the emis-
sion is estimated as:
1 x (100% - 85%) x 0.4364 = 0.07 kg P/MT of NSP.
Product Bagging or Bulk Loading--
The reported controlled emission factor is 0.5 kg P205/MT of NSP. The
emission is estimated as:
0.5 x 0.4364 = 0.22 kg P/MT of NSP.
Summary of Phosphorus Losses to the Environment
A phosphorus mass balance showing values which apply for 1 MT of product
NSP follows:
203
-------
Input
Phosphorus (kg)
Total phosphorus
losses (kg)
phosphorus
90.6
(605 kg x 14.98% p)
Outputs
Product NSP
82.9
(1,000 kg x 8.29% p)
Wastewater discharge
0.007
0.007
Atmospheric losses:
From unloading, grinding,
and feeding ore
From wet scrubber
From product bagging
0.47
0.1
0.15
0.22
Total water effluent and
atmospheric losses
0.477
National Emission for NSP Production
As shown in Table 6-17, the estimated NSP manufacturing rate for the
United States in 1978 is 390,000 MT.
About 4% of the domestic NSP producers discharge wastewater. The rate of
phosphorus discharge in plant wastewater has been estimated to be 0.007 kg p/
MT of NSP product. On this basis, the estimated national emission in 1978 is:
0.04 x 0.007/1,000 x 390,000 = 0.11 MT.
Based on the data shown in Table B-2, the estimated total phosphorus
air emissions during manufacture of NSP amount to 0.47 kg P/MT of product.
Thus, the national air emission for 1978 for NSP production is estimated as:
0.47/1,000 x 390,000 = 183 MT of phosphorus.
204
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EXAMPLE C: ESTIMATES OF PHOSPHORUS EMISSIONS FROM PRODUCTION OF PHOSPHORUS
TRICHLORIDE
The methodology used in this example is also representative of that used
for each of the following production activities.
.
Production of elemental phosphorus
. Production of phosphoric acid by the dry process
. phosphorus pentoxide production
. Phosphorus oxychloride production
. Phosphorus penta sulfide production
. Sodium tripo1yphosphate production
.
Production of sodium phosphates
. Production of food grade calcium phosphates
. Production of laundry detergents
. Metal surface treatment
A representative process flow diagram for production of phosphorus tri-
chloride is shown in Figure B-3.
Material Balance Data
Published information shows that a typical material balance (basis 1 MT
of phosphorus trichloride product) for the process is as follows:
Raw materials
Kilograms
Product
Kilograms
Phosphorus
2381
815 ~
PC13
1,000
Chlorine
205
-------
Chlorine
liquid
Phosphorus
Storage Tank
238 kg P
I
Batch
Reactor
Raw Waste
~ Phossy Water
C)\ 0 . 24 kg P
Waste Residue
( Solid)
O. 02 kg P
Phosphorus Values per MT
Input P = 238 kg P
Output P = 226 kg P
Atm Losses = 10.8 kg P
Water Losses = 0.05 kg P
Solid Residue = 0.02 kg P
Product
Reflux
Condenser
Holding
Tank
Transfer to
Containers
Condenser
Water
Water
Discharged
Wastewater
0.05 kg P
Wastewater
Treatment
Effl uent
0.94 kg P
Note: Total Atmospheric Losses from Transfer and Storage
of P and PCI3 are 0.45 kg P/MT of Product PCI3
Figure B-3.
Flow diagram for production of pho~phorus trichloride.
PCI3
Product
1 MT
226 kg P
Atm
Emi ssion
10.4 kg P
-------
The phosphorus content in the pure product is.22.55%; therefore, the
estimated amount of phosphorus contained in 1 MT (1,000 kg) of PCl] is
225.5 kg.
Wastewater Effluent
Raw wastes are generated by phosphorus storage and transfer, wet-scrubbing
of gases, vessel cleaning, and leaks and spills.
Wastewater discharged from the scrubber for distillation tail gases is
reported to contain 2.5 kg of H3P03 per metric ton of product. The estimated
phosphorus content is calculated as:
2.5 x 30.975/82 = 0.94 kg P/MT of
PC13.
One kilogram of phosphorus is reported to be discharged in the phossy
water waste for each metric ton of phosphorus consumed in the production
process. Production of 1 MT of phosphorus trichloride requires 0.238 MT of
phosphorus; therefore, the total phosphorus discharged in phossy water is
0.238 kg/MT of PC13. Combining this figure with the 0.94 kg stated above gives
a total phosphorus content in wastewater of 1.18 kg P/MT of PC13 product.
It is assumed that the wastewater is treated in pollution control equip-
ment so that the phosphorus contained in treated discharged wastewater is
0.05 kg/MT of PC13 product. This value is specified in the EPA effluent limita-
tion guidelines for best practicable technology currently available.
Atmospheric Emissions
The transfer and storage of phosphorus and phosphorus trichloride account
for the equivalent loss of 2 kg of PC13 per metric ton of PCl3 product. Thus,
207
-------
the corresponding emission of phosphorus can be calculated as:
30.975/137.35 x
2 = 0.45 kg P/MT of PC13.
The quantity of phosphorus discharged from scrubber vents can be calculated,
by difference, from a material balance (inputs = outputs plus losses), using
data shown on Figure B-3, as follows:
238 - 226 + 0.24 +0.02 + 0.94 + 0.45 +
scrubber vent emission. Scrubber vent emission = 10.35 kg P/MT of PC13.
Thus, the estimated total atmospheric loss is:
10.35 + 0.45 = 10.8 kg p/
MT of PC13.
Solid Waste Residue
Solid waste, which is removed periodically from the reactor-still, re-
portedly contains 0.1 kg of PC13 per metric ton of product. The quantity
of phosphorus contained in this waste is calculated as follows:
0.1 x 30.975/
137.35 = 0.02 kg P/MT of product PC13.
Summary of Phosphorus Losses to the Environment
A phosphorus mass balance showing values which apply for 1 MT of product
phosphorus trichloride follows.
Input
Phosphorus
. (kg)
phosphorus
238
Outputs
Product
226
Accounted for phosphorus losses
Total wastewater losses
Total atmospheric losses
Total solid waste residue
Total
0.05
10.8
0.02
10.87
Unaccounted for phosphorus
1.13
208
-------
.
---- ------------
National Emission for PC13 Production
As shown in Table 6-17, the estimated PC13 manufacturing rate for the
United States in 1978 is 96,400 MT. On this basis, the national emissions of
phosphorus can be estimated as follows:
For discharged wastewater, the estimated phosphorus emissions are:
0.05/1,000 x 96,400 = 4.8, or approximately 5 MT.
For air emissions, the calculated phosphorus losses are:
10.8/1,000 x 96,400 = 1,041 MT.
For solid wastes, the estimated phosphorus losses are:
0.02/1,000 x 96,400 = 1.9, or approximately 2 MT.
EXAMPLE D: ESTIMATES OF PHOSPHORUS LOADING IN TREATED EFFLUENT FROM MUNICIPAL
SEWAGE TREATMENT PLANTS
The general procedures used for calculation of the phosphorus loads in
treated effluent from municipal sewage treatment plants are presented in the
body of this report. The following Table (Table B-3) shows the types of data
used in these estimates, and provides a state-by-state evaluation of the
phosphorus loads. These data were developed from information provided in the
1976 Needs Survey.* These tabulated data serve to clarify the methodology
used in determining the regional phosphorus loads shown in this report.
-I(
Municipal Construction Division of U.S. Environmental Protection Agency
(EPA 430/9-76-010, 430/9-76-011, and 430/9-76-012). Cost Estimates for
Construction of Publicly Owned Wastewater Treatment Facilities--1976 Needs
Survey.
209
-------
:'.1Dld B-J.
~ST!11ATED 1978 ?~OSPHORUS LOAD !"ROM ?'.'BLICLY J:oNED :'!l~IC:PAI. TREAnl!:JT PI..I.'lTS
P Ir. treattd eff!.\,;ent
, ..:o:nesti;: p, cc::mercial
Population now and nousl!ho ld and L:1dusl:rial P total
State (, 1,000) . Pri. .. S~c. .. :'er. (, 100 I1t.rs/day) ? removal (ill: I :,ea rJ (ill: I yea r) (:.rr/year)
~ortheast:
~ 521 5.9 :1.0 7.6 379 1.1 370 643 1,21)
NH ~07 14.1 14.6 6.8 ~31 2.7 ~51 346 797
~1: 287 17..0 26.1 3..0 301 7.9 Jea 1,J66 1,674
~ 1,662 ".1 IG.7 6.0 1,205 3.9 I, il6 I,nl ) ,637
1! 498 S.~ I:,J 3.9 408 'J.: 539 ;69 t,J0S
.:Ij 2,288 10.1 50.1 :'.3 1,644 :.2 2,365 2..018 : ,153
5ubtoca 1 6,149 7':36J t!.,J12
~!1ddle Atlantic:
~y 17,590 :1~.3 2~.2 25." 9,;>66 :'.5 13,~14. IQ,903 :9,117
~'( 7,1':"7 17.J lJ.3 32 .'~ !o., t36 1..3 7 ,~':::S .,311 I, ,5:9
?\ 1'),641 13.':" :3.7 11.6 7,351 ".J t~ ,254 ll,J5J ~:. 6:J
"Subtotal 36,306 15, ;91 'ITJH
jouci1 At Ian ti c:
JE 385 -" ... 13.0 366 ,.. 3:6 .l5 ~5i
:-ID J ,2CO L.3 td.; 23.. ~.oD9 14.0 2, :3J ~ ,J89 J ,3:2
DC 1, ~65 )..J "" 1~4.. i 1,11.3 ~() .~, ~, J 79 330 2,':13
VA 3,6'::'9 17..... 1':'.1 25.0 I, ili ' , 3.661 1,')7; ., :26
:/', ~55 U.j ~ ":" 1~.3 5iJO ': .~) :, )62 ",4 1 ,336
::c ;, J66 3. ~ 1::".3 :6. i 2, J03 L.~ :, »5 ~ ,col) .5 ,63;'
;c ~ ,:'25 i..:o ':2.9 13.0 1.313 ' ., ~ ,008 . ,0,)"; -.=6,)
~A 2,030 Ll..3 26.d ':0..3 2,331 ~.... 3, ;31 ),;2 ~ ~ ~, ~qi
:L ~,S24 ).3 ~0.o ':',).2 ':,?'53 " 5, i7~ ~ :,.,!
3ubcoc31 "::,12£ 1] ,37:' ); ,JJ:
::ast :Ior:~ +:I!nt:'al:
:0 0 ,3.:..4 17.~ I.J.) "3..0 0,3.:..6 ~5.3 3. ,13 7, !.o;9 1':, :;1::
'., ,:',297 ':).j i.3.1 23.3 3..)6;> o5.J ..., ~ ~ i ~,3:6 3,Jn
~ i, LOI ~.6 15.':' )6.3 '1,35::: ~.... 1 :',:;) 16, :~... :5. ';')7
~I i ,7.44) 5... ~6.2 L~..... 6,313 li.; 6, i:.2 ll).':r)~ 16, ~:'6
:-/1 J ;.:.;: ;." :9... 2. t.... 2,514 13..... j .';1>; ~ i~:~~~
3ubtoc.11 J: ,.oj I -i.:>.:'':''
':;.a5C 50uch '':;cntra 1:
~-[ :,6J~ 6.6 l:.J 1~.2 1,066 ~.3 ~ ..5~c l,~J: 3,,)'H
T~I 2,6.34 i.5 '..0 17.J 2. ,J.)J oJ. ~ ~, 730 J,J~ 0, \'1':'
.'.L .2 ,330 3.1 2.5.3 26.3 1,599 J.0 .:, -J~ 2,JIJ8 .., ~ ..6
:.15 l,26J 17... ':1.6 12.; t ,3:9 :.i. 1,5J3 .;, :JoJ ~
5ubtotal 3,JOo l'j, ;15 l':'.:.!S
.';~St ;":art~ ::cnt=aL:
:~ 3,,j1.5 -0- 13.7 23.5 .:, ;~£. H' j .52: .: ,lici ..
,A ':,-01 29.; li..3 l;.; ~, -......... "J -.. -.. :,d~1 - ,: ~c
~!C -, ;'j::: -'1..... ':3.2 3 . ~ :.-.:!'-? ).::: ;,:U ':,;' 13 . ~. ~
;i:J :..2i ~.oJ :J.o ,..J. ~ :;; :.J -51 .00
5j) .08 ..-.- L3.3 ':1.0 1';1 ).J ...30 125 :61
;~::: I, ,30 1-5.6 --... 3':..j ji 1 :.~ ~.,:...j '"6L .:, ),)..
:.5 1 ,3~5 "":.0 ,.. - OJ ;~ ).J 2,27') ~ : ,1:6
5ubtcta1 ,0,2;6 5.0':'';' .:~
1.,;onu:1ueu)
210
-------
~.b l. g-J.
,cmt~l1ueci)
? :.:'l ::'ed~-ed. ~if:'':'II!n.c;
,5:a.te
?OPULiCi>X1
(x 1,000)
~. P:-i.
~. Sec.
~ p r~ovaL
p, ioroeHl':
:!nJ ~\Jus.K :J3 :9.3 1..3 ,.J l:b ,j.~ 2.H t':': .:J
~! ~27 ;..... tl.; ~ Jj.';' ;:i .4 ;:~ Z2.:. 030
,;lJcc.JcJ.l -' ,..:.- 1m ;~, :01
!'Jt.al ':niced 3C,a:.!5 ~ :,ounda\l :0 nearest [,JOO) t4i,',jI)I,) 1J';, Jr;Q Jl'J,:OO
211
-------
',,-
TeCHNICAL REPORT DATA
(P/eare read luU/'Uctiunr on the reverfe before completing)
1. REPORT NO. 12. 3. RECIPIENT'S ACCESSIONl>NO.
EPA-560/2-79-002
-
~. TITLE AND SUBTITLE 5. REPORT DATE
Analysis of the Sources of Phosphorus in the Environment March 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO.
Charles E. Mumma, Fred C. Hopkins, Kathryn Bohannon,
Th oma s IV. Lapp
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
Midwest Research Institute Task No. 1
425 Volker Boulevard 11. CONTRACT/GRANT NO.
Kansas City, Missouri 64110 68-01-3896
.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
Environmental Protection Agency Final Report
Office of Toxic Substances 14. SPONSORING AGENCY CODE
Washington, D.C. 20460
15. SUPPLEMENT AR Y NOTES
Roman Kuchkuda, Project Officer
16. ABSTRACT
A qualitative and quantitative assessment of the principal sources of phosphorus re-
lease to the environment was performed. Natural sources were not extensively evaluated nor
were they quantified. Nonpoint sources were identified by land use; discharge data for
specific land uses TtJere obtained from the literature. Point sources were estimated on the
basis of model flow diagrams and phosphorus material balances; no measured levels were
utilized. The total national phosphorus emissions to air and water in 1978 were about 2.9
million metric tons. Of this amount, approximately 87.6% was attributable to nonpoint
sources and 12.4% to point sources. Major nonpoint contributors are cropland runoff and
pasture and rangeland runoff; for the major point sources, municipal sewage treatment was
the largest single contributor. From the data developed for the national emissions, a re-
gional assessment was performed for Florida to evaluate the difference in phosphorus
sources in regions and for the nation. A cursory analysis was also performed of detergent
phosphate controls in Indiana and New York. The analysis addressed surface water geog-
raphy, location and nature of phosphorus water quality problems, and the impact of deter-
gent phosphate control.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C. COSA TI Fic=ldlGroup
Phosphorus
Phosphates, inorganic
Manufacturing process
Industrial waste
Eutrophication
Nutrient enrichment
1'3. ::':S,RI8UTION STATEMENT 19. SECURITY CLASS (This Report) 21, NO. OF PAGES
Unlimited distribution Unc lassified 226
20. SECURITY CLASS !Tltis pagel 122. PRICE
Unclassified
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EDITION IS OBSOLETE
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