EPA 440/1-75/043
GROUP I, PHASEII
Development Document for Interim
Final Effluent Limitations Guidelines
and Proposed New Source
Performance Standards
for the
OTHER NON-FERTILIZER
PHOSPHATE CHEMICALS
Segment of the
PHOSPHATE MANUFACTURING
Point Source Category
*' m.m ~b
3) «-*2^^R*1 UJ
*L PRO^0^
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
January 1975
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DEVELOPMENT DOCUMENT FOR INTERIM FINAL
EFFLUENT LIMITATIONS GUIDELINES
AND PROPOSED NEW SOURCE PERFORMANCE STANDARDS
FOR THE
OTHER NON-FERTILIZER PHOSPHATE
CHEMICALS SEGMENT OF THE
PHOSPHATE MANUFACTURING
POINT SOURCE CATEGORY
Russell E. Train
Administrator
James L. Agee
Assistant Administrator for Water
and Hazardous Materials
Allen Cywin
Director, Effluent Guidelines Division
Chester E. Rhines
Project Officer
January 1975
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
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Index
TITLE PAGE
ABSTRACT
TABLE OF CONTENTS
Section I
Section II
Section III
Section IV
Section V
Section VI
Section VTI
Section VIII
Section IX
Section X
Section XI
Section XII
Section XIII
Section XIV
Conclusions
Recommen dations
Introduction
Industry Subcategorization
Waste Characterization
Selection of Pollutant Parameters
Control and Treatment Technology
Cost, Energy and Non-Water
Quality Aspects
Best Practicable Control Technology
Currently Available, Interim Final
Guidelines and Limitations
Best Available Technology Economically
Achievable, Interim Final
Guidelines and Limitations
Proposed New Source Performance
Standards and Pretreatment Standards
Acknowledgments
References
Glossary
age
1
5
9
21
25
45
55
69
73
81
85
95
97
99
TV;
AGMCY
ii
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•^
FIGURES
UI-1 Defluorinated Phosphate Rock
Plant Locations
HI_2 Defluorinated Phosphoric Acid
Plant Locations
20
IH-3 Sodium Phosphates Plant Locations
V-i Defluorinated Phosphate Rock
Fluid Bed Process
V-2 Defluorinated Phosphoric Acid 4Q
Vacuum Process
v-3 Defluorinated Phosphoric Acid ^
Submerged Combustion
v-4 Defluorinated Phosphoric Acid ^
Aeration Type
V-5 Sodium Phosphate Process from
Wet Process Phosphoric Acid
VII-1 contaminated (Pond) Water Treatment 67
Yin-1 Water Effluent Treatment Costs 72
iii
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ABSTRACT
EL£Ei';g: -«"• ss.-.sesr ssfe- £
The three main outputs from the study were-
and sodium phosphates. Notice of interim final effluS^
^^^%£tdCline;.ha: been drafted ^"exfsSnglourc^s
a^ailaCle !nd Practjcable control technology currently
available, and for best available technology economicallv
ie Stand-ds °f pLlormancealfo?
pretreatment standards for
Treatment technologies such as in-process or end-of-process
on units are available singly or in comb in at--inn -t-n
the recommended effluent guidelines. "inarion tc
IV
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SECTION I
CONCLUSION
This study was conducted for the purpose of extending
effluent limitations guidelines and standards of Performance
to all the major chemical products of the Phosphate
Manufacturing Point Source Category, and was directed at
prSduc?s neither covered in the Phase I phosphate
manufacture study, nor included among the fertilizer
phSsphate products. The Phase I phosphate study covered the
production of phosphorus, and products derived from
phosphorus. This Phase II study covers phosphate chemicals
produced by the defluorination of phosphate rock, the
derluorination of phosphoric acid, and the sodium phosphates
produced from wet process phosphoric acid. The
Subcategories previously established for the Phosphate
Manufacturing Point Source Category were:
The Phosphorus Derived Chemicals Segment
Subpart A - Phosphorus Production Subcategory
Subpart B - Phosphorus Consuming Subcategory
Subpart C - Phosphate Subcategory.
The Other Non-Fertilizer Phosphate Chemicals Segment,
now added, include:
Subpart D - Defluorinated Phosphate Rock Subcategory
Subpart E - Defluorinated Phosphoric Acid Subcategory
Subpart F - Sodium Phosphates Subcategory
The study of subparts A, B and C (Phase I) has been
completed and regulations published in the ^der^^e^is^r'
Title 40, Part 422, page 6580, February 20, 1974. This
Phase II study deals only with Subparts D, E, and F.
The major waste water pollutant problems for Subparts D, E
and F processes of phosphate chemicals manufacture are much
closer associated with the fertilizer phosphate industry
problems than with Subpart A, B and C phosphate
manufacturing problems. The phosphoric acid raw material
utilized for making defluorinated phosphoric acid, for
making sodium phosphates, and used as a reagent in
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^hJ luPrina tlQn of rock, is exclusively produced by the wet
Phosphoric acid process. The purification processes car rlld
on constantly in this segment create fluoride waste water
nhoSirj* Resfues from salt purification processes conJain
Drobl^f "Sldues ?lon9 with s*lt contaminants that create
problems if recycled indefinitely, and require blowdown
The contaminated water recycle pond, heart of the fertil^Sr
phosphate waste water treatment system, provides the belt
FlSorid^anS I?'. dealjng W±th most of these component?
Fluorides, sulfates and phosphates deposit in the recycle
pond under favorable water balance circumstances
rad^10^S WltK?Ut dischar9e °f Process waste water ?he
radium 226 problem is similar to that in the fertilizer
phosphate industry. Radium 226 can be and is controlled by
clar?f??^ Y a*kaline coagulation reaction and effective
SeSS J carrying out the double lime effluent
treatment process. Extremely rigorous controls are
essential to prevent flow into ground water through channels
be bu?ltn,nS lm?r°per ,la?oon Iinin9 operations. Dikes mus?
be built and maintained in a manner that eliminates failure.
Dike failures have occurred in the slime ponds of phosphate
mining operations. Dike failure is a serious po?IntJa?
hazard from contaminated water ponds. Dike failure would
lead to massive pollution by at least 5 highly objectionable
pollutants radium 226, fluoride, acidic wastes, phosphate
and suspended solids. Recommendations that drastically
reduce the dike failure hazard are provided in this
development document.
The information on fertilizer phosphates in the Development
Document for Effluent Limitations Guidelines and Slw Source
smentth basic fertilizer cecs
segment of the fertilizer point source category is fully as
important as the information gathered in ?his study
"" ^ nc fert±lizer hos
men of th mcs
segment of the phosphate manufacturing point source
category. Practicable treatment is available to ?hese
manufacturing operations only through utilization of the
recirculation and reuse lagoon developed for waste water
treatment in wet phosphoric acid manufacture.
pEosnho^ odefluorinated Phosphate rock and defluorinated
?e^5£££?M H Processes the techniques and treatment
technologies do exist and are commercially practiced to
achieve essentially no process waste water effluent
discharge to navigable waters. The exception to tSs
situation would be an adventitious condition such as
abnormal rainfall accumulation. Under such a condition
treatment technology does exist to treat contaminated
process waste waters for reduction of contaminants on a
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commerically demonstrated basis to the interim final and
proposed effluent limitation guideline levels.
in the sodium phosphates process, technology does exist to
continuously treat the process waste water effluent to
commercially demonstrated levels that meet the interim final
and proposed effluent limitation guideline levels.
in-process modifications and end-of-process plant waste
water treatment technologies are in current industrial use
to" enSle new non-fertilizer phosphate chemicals
manufacturing plants to meet the proposed new source
standards.
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SECTION II
RECOMMENDATIONS
These amendments to the phosphate manufacturing point source
category are being introduced to include the defluorinated
phosphate rock subcategory (Subpart D), the defluorinated
phosphoric acid subcategory (Subpart E) and the sodium
phosphates subcategory (Subpart F) .
Interim final effluent limitations have been written- for
existing sources, covering both best practicable control
technology currently available (BPCTCA), and best available
technology economically achievable (BATEA).
Notices of proposed effluent limitations and guidelines have
been written for
1. Pretreatment standards for existing sources.
2. Standards of performance for new sources (NSPS).
3. Pretreatment standards for new sources.
The regulations are about to appear in the Federal Register;
the Federal Register presents the regulations in official
form.
The effluent guidelines limitations written for the
defluorinated rock and the defluorinated acid subcategories
include both wastewater volume and wastewater component
concentration limitations. The guidelines written for the
sodium phosphates subcategory are based on weight units of
pollutant per weight unit of product.
Defluorinated Phosphate Rock and Defluorinated Phosphoric
Acid Subcategories
The permissible wastewater volume discharges have been
established by the specialized definitions and special
formulae developed for computing the excess rainfall over
evaporation cited in Sections IX, X and XI for the
recirculation and reuse ponds that are utilized in treatment
of wastewater of these subcategories. It is essential to
refer to these specialized definitions and formulae for full
comprehension of the regulations. The permissible discharge
for a pond is the excess of rainfall collected by the pond
over evaporation from the pond surface.
The permissible discharge volumes for existent ponds for
BPCTCA, BATEA and pretreatment may include rainfall
collected by the outer surface of the dam and by a seepage
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interception ditch around the dam. The figure used for this
outer surface and ditch area may not be greater than 30
percent of the pond surface at maximum capacity.
Discharges from new source ponds and from ponds constructed
on or after the date of these regulations must be based upon
rainfall on the pond surface area at maximum capacity.
Ponds utilized for BPCTCA must provide sufficient freeboard
to contain the heaviest rain expected in a ten year period.
BATEA and NSPS ponds must provide sufficient freeboard
contain the heaviest rain expected in a 25 year period.
to
The regulations controlling permissible discharge volumes
and freeboard requirements of ponds were established after
extensive discussions with representatives of industry.
Concentrations of pollutant components
discharges for BPCTCA, BATEA and NSPS:
permitted in
Effluent
Characteristic
Total phosphorus
(as P)
Fluoride
TSS
PH
Maximum for
any one day
(Metric units, mg/1)
70
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
35
30 15
50 25
Within the range 6.0 to 9.0
Concentration of pollutant components permitted by proposed
pretreatment regulations:
Pollutant or
Pollutant Property
Pretreatment
Standards
Maximum for
any one day
Average of daily
values for thirty
consecutive days
shall not exceed
(Metric units) mq/1 of effluent discharged
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BODjj No limitation
TSS No limitation
pH No limitation
Total phosphorus 70 35
Fluoride 30 15
The volume of discharge permitted under pretreatment is
determined by the interim final regulations for best
practicable control technology currently available.
Sodium Phosphates Subcategory
The following limitations establish the quantity or quality
of pollutants or pollutant properties controlled by interim
final regulations for best practicable control technology
currently available:
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall_not exceed
(Metric units, kg/kkg of product)
TSS 0.50 0.25
Total phosphorus 0.80 0.40
(as P)
Fluoride 0.30 0.15
pH Within the range 6.0 to 9.0.
(English units, lb/1000 Ib of product)
TSS 0.50 0.25
Total phosphorus 0.80 0.40
(as P)
Fluoride 0.30 0.15
pH Within the range 6.0 to 9.0.
The following limitations establish the quantity or quality
of pollutants or pollutant properties controlled by interim
final regulations for best available control technology
economically achievable and for proposed new source
performance standards:
Effluent Effluent
Characteristic Limitations
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Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed_
(Metric units, kg/kkg of product)
TSS 0.35 0.18
Total phosphorus 0.56 0.28
(as P)
Fluoride 0.21 0.11
PH Within the range 6.0 to 9.0.
(English units, lb/1000 Ib of product)
TSS 0.35 0.18
Total phosphorus 0.56 0.28
(as P)
Fluoride 0.21 0.11
PH Within the range 6.0 to 9.0.
The following limitations establish the proposed
pretreatment standards for existent sources and for nev
sources:
Pollutant or Pretreatment
Pollutant Property Standards
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed
(Metric units) kq/kkg of product
BOD5 No limitation
TSS No limitation
pH No limitation
Total phosphorus 0.80 O.UO
.Fluoride 0.30 0.15
(English units) Ib/10OP Ib of .product
BOD5 No limitation
TSS No limitation
pH No limitation
Total phosphorus 0.80 0.40
Fluoride 0.30 0.15
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SECTION III
INTRODUCTION
Section 301 (b) of the Act requires the achievement by not
later than July 1, 1977, of effluent limitations for point
sources, other than publicly owned treatment works, which
are based on the application of the best practicable control
technology currently available as defined by the
Administration pursuant to Section 30U (b) of the Act.
section 301(b) also requires the achievement by not later
than July 1, 1983, of effluent limitations for point
sources, other than publicly owned treatment works. These
are to be based on the application of the best available
technology economically achievable which will result in
reasonable further progress toward the national goal of
eliminating the discharge of all pollutants, as determined
in accordance with regulations issued by the Administrator
pursuant to Section 304(b) of the Act. Section 306 of the
Act requires the achievement by new sources of a Federal
standard of performance providing for the control of the
discharge of pollutants which reflects the greatest degree
of effluent reduction which the Administrator determines to
be achievable through the application of the best available
demonstrated control technology, processes, operating
methods, or other alternatives, including where practicable,
a standard permitting no discharge of pollutants.
Section 304 (b) of the Act requires the Administrator to
publish within one year of enactment of the Act, regulations
providing guidelines for effluent limitations setting forth
the degree of effluent reduction attainable through the
application of the best control measures and practices
achievable including treatment techniques, processes and
regulations proposed herein set forth effluent limitations
guidelines pursuant to Section 304(b) of the Act for the
fertilizer manufacturing category of point sources.
Section 306 of the Act requires the Administrator, within
one year after a category of sources is included in a list
published pursuant to Section 306 (b) (1) (a) of the Act, to
propose regulations establishing Federal Standards of
performances for new sources within such categories. The
Administrator published in the "Federal Register of January
16, 1973 (38 F.R. 1624), a list of 27 source categories.
Publication of the list constituted announcement of the
Administrator's intention of establishing, under Section
306, standards of performance applicable to new sources
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within the fertilizer manufactuirng category of point
sources, which included within the list published January
16, 1973. T
The effluent limitations guidelines and standards of
performance proposed in this report were developed from
operating data, sampling, and information gathered from six
plants. These plants represent a very high percentage of
the total number of the industrial units in two of the three
study processes. The methods and procedures used in the
accumulation of the overall information are described in the
following paragraphs.
Summary of Methods Used for Development of the Effluent
Limitations Guidelines and Standards of Performance
The effluent limitations guidelines and standards of
performance proposed herein were developed in the following
manner. The point source category was first studied for the
purpose of determining whether separate limitations and
standards are appropriate for different segments within the
category. This analysis included a determination of whether
differences in raw material used, product produced,
manufacturing process employed, age, size, waste water
constituents, and other factors require development of sepa-
rate limitations and standards for different segments of the
point source category.
The raw waste characteristics for each such segment were
then identified. This included an analysis of (1) the
source flow and volume of water used in the process employed
and the sources of waste and waste waters in the plant; and
(2) the constituents (including thermal) of all waste
waters, including toxic constituents and other constituents
which result in taste, odor, and color in the water or
aquatic organisms. The constituents of the waste waters
which should be subject to effluent limitations guidelines
and standards of performance were identified.
The range of control and treatment technologies existing
within each segment was identified. This included an
identification of each distinct control and treatment
technology, including both inplant and end-of-process
technologies, which are existent or capable of being
designed for each segment. It also included an
identification in terms of the amount of constituents
(including thermal) and the effluent level resulting from
the application of each of the treatment and control
technologies. The problems, limitations and reliability of
each were also identified. In addition, the nonwater impact
10
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of these technologies upon other pollution problems,
including air, solid waste, noise and radiation were also
identified. The energy requirements of each control and
treatment technology was identified as well as the cost of
the application of such technologies.
The information, as outlined above, was then evaluated in
order to determine what levels of technology constituted the
"best practicable control technology currently available",
the "best available demonstrated control technology,
processes, operating methods, or other alternatives". In
identifying such technologies, various factors were
considered. These included the total cost of application of
technology in relation to the effluent reduction benefits to
be achieved from such application, the age of equipment and
facilities involved, the process employed, the engineering
aspects of the application of various types of control
techniques, process changes, nonwater quality environmental
impact (including energy requirements), and other factors.
Delineation of Study
The industry is characterized by a relatively small number
of plants. Only 1 plant exists for the sodium phosphate
subcategory. Some of the plants did not cooperate with the
study because of trade secret factors. Fortunately, the
technology developed for the phosphorus derived segment of
phosphate manufacturing, and for the phosphate subcategory
of fertilizer manufacturing is extremely well suited for
handling the waste water problems of this segment of the
industry. The background technology has been utilized
extensively in establishing standards for the industry.
The effluent limitations guidelines and standards of per-
formance proposed in this report were developed from
operating data, sampling, and information gathered from 6
plants. The methods and procedures used in the accumulation
of that data is described in the following paragraphs.
Identification and categorization of the 3 processes covered
in this report were made during the preparation of the Phase
I portion of the industry report on Phosphorus Derived
Chemicals. These are:
Defluorinated Phosphate Rock (Subpart D)
Defluorinated Phosphoric Acid (Subpart EL
Sodium Phosphates (Subpart FL
(produced from wet process phosphoric acid)
11
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Basis for Definition of Technology Levels
The validated data and samples described in the foregoing
pages were the primary basis for choosing the levels of
technology which were considered to be the "best practicable
control technology currently available", the "best available
technology economically achievable", and the "best available
demonstrated control technology, process operating methods,
or other alternatives". This selection of the separate
technologies, of necessity, required consideration of such
additional factors as evaluation of the engineering and
operational problems associated with the technology, effect
on existing processes, total cost of the technology in
relation to the effluent reduction that would be realized,
energy requirements and cost, the range of control
variations on contaminant concentration and/or quantity, and
non-water quality environmental impact. Information
regarding the influence of these diverse factors was
obtained from a number of sources. These sources include
government research information, published literature, trade
organization publications, United States process patents,
and qualified consultants.
Implementation
The value of a study such as this is entirely dependent upon
the quality of the data from which it is made. Particular
attention was, therefore, directed to selecting criteria for
determining the commercial installations to be visited and
from which to collect information.
In this Phase II phosphate study the selection of individual
plants for participation in the survey required a minimum of
consideration after the initial U. S. industry plant identi-
fication. Two of the three processes had less than five
total U. S. operating plants. The third process represented
a slightly larger number of operating plants, nine, and was
found to have essentially identical water usage, water
management and effluent treatment characteristics as one of
the Phase I Phosphate Fertilizer Industry processes.
Because of the relatively few plants involved in each of the
Phase II processes, the consideration of exemplary plant
selection for the survey was not used. For one process, all
U. S. plants were included. For another, all except one U.
S. plant were included. For the third process, its close
relationship to a similar Phase I process necessitated that
only two plants representing each of the two different
12
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process variations in industrial use be included in the
survey.
Contact was then made with each of the plants selected in
the separate processes to establish a time for a screening
visit. The screening visit had the objective of informing
the plant manager on the purpose and intent of the study.
Information acquired during the visit was used to determine
whether that particular plant was to be included in the
study or whether other plants and/or conditions better
exemplified industry standards. The plants included in the
survey were found to have good effluent monitoring programs
in effect and were maintaining comprehensive records. Study
covered the important fluoride, suspended solids, phosphate,
radium 226, and pH parameters. In some cases the plant
records did not necessarily isolate the liquid streams to
and from the specific process unit involved in the survey
but did provide valuable information on water management
control.
A comparative evaluation was made of the various plants
visited. This evaluation was based upon the criteria used
in the Phase I study. It consisted of the following points:
1. Discharge_Effluent Quantities
Installations with low effluent quantities including
some plants operating with no discharge of process
waste water.
2. Effluent Contaminant Level
Installations with low effluent contaminant
concentrations and quantities.
3. Effluent Treatment Method and Effectiveness
Installations utilizing the best currently available
treatment methods, and control equipment.
4. Water Management Practice
Installations with utilization of good management
practices such as main water re-use, planning for
seasonal rainfall variations, in-plant water seg-
regation and proximity of cooling towers to
operating units where airborne contamination can
occur.
5- Land Utilization
13
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Consideration of land area involved in waste water
effluent control system with the most acceptable being
those with the least area.
6• Air Pollution Control
Consideration given to those plants with the most compre-
hensive and effective air pollution control. In turn
liquid effluent from such plants may represent the most
serious waste water effluent condition. Major air
pollution problems considered were fluorine, sulfur
dioxide and radon 222.
7. Geographic Location
Consideration given to those facilities in close proximity
to sensitive vegetation, and with high population density.
Land availability and local and state restrictions
and standards were considered. The greatest attention
was directed to rainfall and evaporation conditions
in the area.
8• Management Operating Philosophy
Plants whose management insists upon effective equipment
maintenance and housekeeping practices.
9. Diversity of Processgs
On the basis that other criteria are met, then
consideration was given to installations having a
multiplicity of processes.
Each above criterion was assigned a range of numerical
values to allow a comparative evaluation of the different
plants visited in each process category.
Sampling Collection and Validation of Data
The most important item in a study of this nature is to
obtain data representative of a given process under all
conditions of operation and range of production rates.
Steps and procedures used in selecting data, stream
sampling, and sample analysis were all designed to
accomplish this goal to the best possible degree.
An important step toward this objective was the assignment
of only highly experienced operating personnel to the field
work. Three persons were used. The fertilizer plant opera-
14
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ting experience of these three people ranged from a minimum
of 16 years to 24 years. With such operational knowledge it
was possible to expeditiously select data, identify specific
process streams for sampling, and conduct sampling under
readily discernible plant operating conditions. The points
considered and identified in all data collection, sampling,
and validation were:
1. segregation of process effluent streams so that only
an identifiable single process and/or piece of equipment
was represented.
2. Collection of data and samples at different states
of process conditions such as normal steady state, plant
washout when such a procedure is followed on a routine
basis, upset process condition, operation at above/below
plant design rate, and during shutdown conditions if
effluent flow occurs.
3. Evaluation of the effect, if any, of seasonal
rainfall, particularly on non-point source effluent and
ponds.
4. Establishment of the existence of flow measurement
devices and/or other means of quantitatively measuring
effluent flows.
5. Making positive identity of the type, frequency, and
handling of the samples represented by collected data -
i.e., such items as grab, composite, or continuous type;
shift, daily or weekly frequency, etc. All samples col-
lected by the contractor were composite samples.
6. Validation of data through determination of plant
laboratory analytical procedures used for sample
analysis, check samples analyzed by independent
laboratories, and/or DPG sampling under known and
defined process conditions with sample analysis by an
accredited commercial laboratory, was completed at each
plant. A total of 6 plants were visited and data were
collected at each plant.
GENERAL DESCRIPTION OF THE INDUSTRY
The segment of the U.S. phosphate industry included in this
Phase II survey includes phosphate manufacturing processes
which utilize phosphate rock or wet process phosphoric acid
as basic raw materials. Phosphate products manufactured
from these processes are utilized as animal feed
15
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ingredients, fertilizer intermediates, and high quality
sodium phosphate salts.
One of the phosphate processes is the defluorination of
phosphate rock. During the early stages of World War II
bone meal for use as an animal feed supplement came into
short supply. This short supply situation spurred activity
for finding an alternate source and/or process to satisfy
this material so important to the production of animal
foodstuffs. Bone meal supplies two important animal mineral
requirements, namely calcium and phosphorus. Lack of
adequate levels of these ingredients can result in such
animal disorders as aphosphorosis, rickets or infertility.
Materials which can furnish these calcium and phosphorus
ingredients can be derived from two general sources. The
natural occurring type materials used for these minerals are
such items as bonemeal, meatmeal and fishmeal. An alternate
source was through processing phosphate rock. The problem
with phosphate rock as a direct source lay in the need to
reduce the 3 to 4 percent fluorine content in the rock to a
level which was not harmful to animals upon ingestion.
The outcome of this animal feed supplement supply problem
was that three methods were developed and put into
commercial operation. Over the past years process and
equipment improvements have gradually proven one process to
have the better overall commercial values. This process is
described in detail on the following pages of this section
and is the process used at the three plants included in the
survey.
The estimated annual U.S. production of defluorinated
phosphate rock for recent years is indicated below.
Estimated Annual U.S. Production
Thousands of kkg (tons)
Defluorinated Rock
18% P Content
1968 1969 1970 1971 1972 1973 1974
373(410) 394(435) 380(430) 394(435) 444(490) 485(535) 485(535)
Plant site locations for U.S. plants are indicated on Figure
III-l.
A second phosphate process included in the study is the
defluorination of wet process phosphoric acid. Acid
defluorination is accomplished commercially by two methods.
16
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The method in most common use is the manufacture of
superphosphoric acid. This process essentially involves the
concentration of phosphoric acid from a 52-51% P2O5
concentration level to a 68-72% P205 level. In the process
of evaporating water from the acid, fluorine is also
removed. The degree of fluorine removal is dependent upon
the initial fluorine level and the final phosphoric acid
concentration. In most cases the fluorine removal is
sufficient to permit use of the concentrated phosphoric acid
for manufacture of animal feed supplements.
Two types of phosphoric acid evaporators are used to produce
superphosphoric acid. One type uses the principle of acid
circulation in a vessel maintained at sub-atmospheric
pressure. This is the type most prominent in the United
States. A second type uses the principle commonly referred
to as submerged combustion. In this type hot gases directly
from a fuel fired combustion chamber are bubbled through the
acid.
The second method of acid defluorination in commercial use
is the combination of the addition of an additive to the
acid which in turn facilitates fluorine removal by aeration.
Defluorinated acid has several end uses. A large percentage
of the defluorinated acid is mixed with limestone to produce
dicalcium phosphate for animal feed supplement use.
Increasingly greater quantities are being used for liquid
fertilizer production. This use, however, does not require
low fluorine content acid. There is also an increasing use
of superphosphoric acid as an intermediate in the production
of dry mixed fertilizer. The advantage in this latter usage
is a combination of reducing fluorine evolution from the
manufacturing process and savings on raw material freight
costs.
The current annual U.S. production of defluorinated
phosphoric acid is estimated at 760,000 kkg (835,000 tons)
P2O5. Plant site locations for U.S. plants are indicated
on Figure III-2.
The third phosphate process included in the survey is the
production of high quality sodium phosphate salts.
Conventionally, high purity phosphoric acid as produced from
thermal or electric furnace operations is used as the raw
material for such compounds. Wet process acid is however,
used by one U.S. manufacturer to produce these compounds
primarily for use as intermediates in the production of
cleaning compounds. The plant site location map for this
type unit is indicated as Figure III-3.
17
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DEFLUORINATED PHOSPHATE ROCK
oo
PLANT LOCATIONS
FIGURE III-l
-------
DEFLUORINATED PHOSPHORIC ACID
PLANT LOCATIONS
FIGURE III-2
-------
SODIUM PHOSPHATES
to
o
PLANT LOCATIONS
FIGURE III-3
-------
SECTION IV
INDUSTRY SUBCATEGORIZATION
The subcategorization developed for this segment of the
phosphate industry was largely determined in the course of
the Phase I phosphate study and the Phase I fertilizer
phosphate study. Phosphoric acid derived from phosphorus is
a much purer product than the wet process acid of the
fertilizer industry. Human food grade calcium phosphates,
most reagent chemical quality phosphate compounds and sodium
tripolyphosphate are made from phosphorus derived acid.
A comparative list of the impurities and physical
characteristics of furnace acid and wet process acid are
indicated in the following table.
Impurities
F
SO3
A1203
Fe203
Water Insolubles
Total Impurities
Density kg/1 (Ib/gal)
a) 27<>C (80°F)
Viscosity, cp
Color
0.6 -
2.7
0.9
1.2
0.8
1.0
Furnace Acid Wet Process Acid
Weight Percent
0.007
0.003
0.001
0.0007
0.012
1.57 (13.1)
18
Colorless
6.2 - 6.6
1.72 (14.3)
85
Pale green to
dark brown
Although the phosphate compounds of highest purity require-
ments are made from phosphorus derived acid, a substantial
demand developed for products of adequate quality for many
uses, but cheaper than the furnace acid derived materials.
Major products in this area are calcium phosphates for
animal feed, defluorinated phosphoric acid and sodium
phosphates. The industry supplied this demand through
defluorination of phosphate rock, and defluorination of
phosphoric acid. The sodium phosphate demand is supplied by
products derived from the purification of wet process
phosphoric acid, derived from calcined rock.
21
-------
Within this group of chemicals, the defluorination of
phosphate rock is carried out by dry calcining, which
distinguishes it sharply from the remaining products derived
through defluorinating liquid phosphoric acid. The most
favorable water balance within the segment is held by this
defluorinated rock process. Substantial evaporation loss
occurs in stack washing to control fluoride emission. The
water used for stack washing picks up substantial fluorine
pollution, much the same as the scrubber water for
fertilizer phosphate plant acid. The major problem is best
handled by recirculation through a contaminated water pond
type of recycle system.
Water is collected from the defluorination of phosphoric
acid. This is water driven from the acid by heat, aided by
air streams and/or vacuum. This water contains the fluoride
contaminant common to phosphoric acid production. The
defluorination processes in use are accompained by the
formation of dehydrated and polymer forms of phosphate from
the orthophosphate in rock and in wet process acid. These
phosphate varieties have high calcium salt solubility; this
introduces a treatment problem lacking in fertilizer
phosphate production if the defluorinatied products get to
the waste water.
Sodium phosphates are produced from conventional wet process
phosphoric acid, which has been derived from calcined rock.
The cacining improves product color through destruction of
organic components. The production of sodium phosphates is
associated with waste water problems similar to the
fertilizer phosphate problems. The conversion of rock to
phosphoric acid is by the usual fertilizer phosphate
process. The purification steps conducted in phosphate salt
manufacture required the blowdown of process water with
fluorine, sulphate and phosphate waste water components, as
well as other salts and solids.
Conventional wet acid production is carried out prior to
production of both defluorinated acids and the sodium salts.
These plants have typical wet acid problems. As a result of
these considerations, and factors developed in the following
sections on manufacturing technology and waste water
characteristics, 3 subcategories have been established for
this segment of phosphate manufacturing:
Subpart D - The Defluorinated Phosphate Rock Subcategory
Subpart E - The Defluorinated Phosphoric Acid
Subcategory
22
-------
SECTION V
WASTE CHARACTERIZATION
The technical aspects of the manufacturing processes are
described in this section, along with identification of
water usage, and the development of waste water flow.
DEFLUORINATED PHOSPHATE ROCK - PROCESS DESCRIPTION
General
As mentioned earlier in Section III, the early World War II
shortage of bonemeal produced the necessary incentive to
find an alternate source of animal feed supplement. The two
ingredients required were calcium and phosphorus and these
two elements were prominently present in apatite type
phosphate rock. The one natural apatite rock ingredient
which prevented its use as an animal feed material was the
relatively high (3.0 - U.0%) fluorine content. Basically
the problem was to find an economical means of
defluorinating the rock and still have an end product which
would be palatably acceptable to primarily cows, chickens
and pigs. Three general methods were developed to
defluorinate the phosphate rock.
One method involved treatment of normal superphosphate-
produced by mixing phosphate rock with sulfuric acid.
Reaction of the phosphate rock and sulfuric breaks the
chemical bond that holds the fluorine in the fluorapatite
lattice. This superphosphate is then subjected to
temperatures which volatize essentially all the fluorine.
The mono and dicalcium phosphate compounds in the material
are converted to alpha and beta tricalcium phosphate during
the heat treatment.
A second method involves treating a prescribed mixture of
phosphate rock and silica in an oil fired shaft furnace.
This also volatizes the fluorine and yields a fused
tricalcium phosphate mass. The hot mass is quenched in
water immediately upon exit from the furnace. Chemical
composition of the product is approximately 28% phosphorus
pentoxide and 0.4% fluorine.
The third method is described as the calcination of
phosphate rock without fusion. It has demonstrated the most
favorable commercial characteristics and has become the most
prominent U.S. defluorination process. There have been
several significant modifications to this process since its
25
-------
initial commercial operation in 1944. Initially the process
utilized a mixture of phosphate rock and silica as a feed
material. The silica used was sand that is a by-product
from phosphate rock beneficiation. Ratio of silica to
phosphate rock was an important criterium in the defluorina-
tion process. This charge of silica and phosphate was then
introduced to a rotary kiln. In the interim years these two
original steps - use of silica ratio and rotary kiln - have
been modified. Silica has been partially replaced with
sodium compounds and the rotary kiln has been replaced by a
fluid bed reactor. Not all U.S. production units utilize
both of these modifications but both are practiced by the
major producers. A more detailed process description of the
process using both these modifications is presented on the
following pages.
The defluorination of phosphate rock as practiced at U.S.
commercial production plants is a process on which there is
a limited amount of published information available. Plant
visits included only guarded technical discussions and
limited plant observations. One of the primary reasons for
these practices is the protection of trade secret
information. U.S. patents were therefore the major source
of process information.
The fluorapatite type of phosphate rock is the primary raw
material. Phosphate content of the rock is typically 35%
P2O5. Other raw materials used in lesser amounts but very
critical to the process include sodium containing reagents,
wet process phosphoric acid and silica. The quantity, point
of addition of these materials to the process, and how they
are mixed with the phosphate rock constitute some of the
know-how involved to realize a workable process and a
consistent product quality. These raw materials are added
in specific quantities or ratios dependent upon the feed
phosphate rock analysis,
The sodium containing reagent is commonly soda ash (sodium
carbonate) which has a Na20 content of approximately 58% or
over 98% Na2CO3. The wet phosphoric acid reagent
concentration used is 45-54% P2O5. Silica addition is in
the form of sand and is dependent on the silica present in
the basic phosphate rock feed. As previously mentioned the
point of addition and how these materials are mixed together
either as a physical mixture or agglomerated into nodular
form is one of the trade secrets. The above described
mixture or charge is then fed into either a rotary kiln or a
fluid bed reactor. In the case of a fluid bed reactor, it
is desirable that the charge be nodular and dried prior to
being fed into the reactor. This is in consideration of the
26
-------
fluid bed characteristics of effecting particle
classification and loss in the exhaust gas. In the kiln or
fluid bed reactor, temperature control and retention time
are the process variables which require close control.
Reaction temperatures are maintained in the 1205 - 1366°C
(2200-2700°F) range with the rotary kiln requiring the uppe^
portion of the range.
Retention time ranges from 30 to 90 minutes with the fluid
bed reactor generally requiring the lesser time.
The state of the charge in the kiln or fluid bed reactor is
highly dependent upon the ratio of the raw materials added
to the phosphate rock. That is, whether the fluorine is
evolved in a minimal time period or in sufficient quantity
and/or whether the charge fuses into an unmanageable mass
that rings or solidifies in the unit. Another critical
factor in these units is that water vapor content be
maintained at a sufficiently high percentage to effect the
required fluorine evolution. An equation representative of
the chemical reaction and fluorine release in the kilns and
fluid bed reactors is:
CalOF2(P04)6 + H20 + SiO2 = 3Ca3(POU)2 + CaSiO2 + 2HF
phosphate rock water silica tricalcium calcium hydrogen
phosphate silicate fluoride
From the kiln or fluid bed reactor the defluorinated product
is quickly quenched with air or water. This is necessary to
maintain the product in the alpha rather than beta
tricalcium phosphate form. The alpha form is the high
solubility material most desirable in the final product.
From this point the product is crushed and sized for storage
or shipment.
Defluorinated Phosphate Rock - Waste_Water_Characterization
As previously mentioned, the detail and amount of specific
information on water usage and effluents received and
verified in this survey was minimal. There were two general
reasons for this situation. One was that none of the plants
had operable flow metering equipment. A second reason is
the point already mentioned - that of reluctance to give
technical data and free access to the plant operating area
due to the many items regarded as trade secrets. From a
practical standpoint such information in this case would
serve only as background data and a better understanding of
the overall process water balance. On those items which are
important to the study such as water management practices,
27
-------
effluent analyses, and permission to conduct sampling of
inlet and outlet effluents there was excellent industry
cooperation and information input.
The following types of water usage and effluents were
identified.
A. Contaminated Water
B. Water Supply
C. Spills and Leaks
D. Non-Point Source Discharges
Each of the above listed items are further identified below
as to flow and contaminant content under their respective
headings.
A. Contaminated Water
The greatest single process water requirement is
for use in scrubbing contaminants from the gaseous
effluent streams. This instantaneous water
requirement is of appreciable magnitude and process
conditions do permit use of recirculated
contaminated water for this service. The quality
of this contaminated water is essentially identical
to that in fertilizer process circulation systems.
Contaminant levels are dependent on such items as
rainfall, extent and degree of water treatment (if
any), and the multiplicity of plants (if any) that
use contaminated water from the same circulation
system. A water analysis obtained from a Plant B
sample during the survey is typical of contaminated
water used in defluorinated phosphate rock process
units.
Contaminated Water Constituents
Parameter Concentration
pH 1.65
Total suspended Solids 16.00 mg/1
Total Solids 2,267.00 mg/1
Chloride (Cl) 101.00 mg/1
Sulfate (S04) 350.00 mg/1
Calcium (Ca) UO.OO mg/1
Magnesium (Mg) 12.00 mg/1
Aluminum (Al) 58.00 mg/1
28
-------
Iron (Fe) 8.30 mg/1
Fluorine (F) 1,930.00 mg/1
Arsenic (As) 0.38 mg/1
Zinc (Zn) 5.20 mg/1
Phosphorus (P) 600.00 mg/1
BOD5 3.00 mg/1
COD 48.00 mg/1
Color #120 (after filter)
Turbidity 45.00 Jackson
Candle Units
The following figures indicate a representative water usage.
These figures will vary within reasonable limits between
plants and at different seasons of the year but are
representative of the magnitude of usage required in the
process.
1/kkg (gal/ton)
45,894 (11,000)
B- Water Supply
Water supply water is defined as essentially
uncontaminated water from such sources as wells,
commercial or municipal water systems, and
impoundment areas for natural rainfall or runoff.
Such water is added to the process for such reasons
as process functions where contaminated water use
is prohibited due to process requirements, make-up
water to the contaminated water system and
equipment, or area wash downs. The following
figures indicate the usage range.
1/kkg (gal/ton)
877 (210)
c- Spills and Leaks
Spills and leaks are collected as part of process
efficiency and housekeeping. Sources of this water
are pump water seals and plant wash up. The
quantity is minor and normally periodic. Spills
and leaks need not indicate bad housekeeping
practices. Some of these, particularly leaks from
pump seals, are an inherent part of the
manufacturing process. However, these must be
brought under control to achieve satisfactory waste
29
-------
water treatment. Control procedures include
maintenance of equipment and collecting of leaks
and spills in the contaminated water pond.
D. Non-Point source Discharge
The origin of this discharge is dry materials -
both raw material and product - which dust over the
plant area usually emitted from conveying
equipment. These materials are then solubized or
sluiced by rain or melting snow into the plant
drainage system.
DEFLUORINATED PHOSPHORIC ACID - PROCESS DESCRIPTION
General
Defluorinated phosphoric acid is to a degree a bit
misleading to persons associated with the fertilizer
industry. The reason being that acid defluorination is
inherently included in the process of evaporating commercial
wet process 54% P2O5 phosphoric acid to the superphosphoric
acid (68-72% P2O5) concentration level. To fertilizer
people therefore, the principal U. S. defluorinated acid
process is better known as a superphosphoric acid unit. Two
different type superphosphoric units are in commercial use
in the U. S.
Another method of defluorinating wet process phosphoric acid
has come into commercial use in the past few years. This
process also uses commercial wet process 54% P205 phosphoric
acid as the raw material. In this process an additive is
mixed with the phosphoric acid to aid in the release and
volatilization of fluorine from the liquid. The mechanism
for fluorine removal from the acid is aeration.
Defluorinated phosphoric acid is used primarily as a raw
material for production of mixed fertilizer goods - both dry
and liquid types. It is also mixed with limestone in the
manufacture of dicalcium phosphate for use as an animal feed
supplement. Approximately 67% of the estimated U. S.
835,000 annual tons P2O5 quantity of defluorinated acid is
used in fertilizer manufacture and 33% in the production of
dicalcium phosphate. The degree of defluorination required
to meet animal feed regulations is that the P to F ratio be
at least 100 to 1.
DEFLUORINATED ACID - VACUUM TYPE EVAPORATION
30
-------
The vacuum type evaporation method for defluorination of wet
process phosphoric acid is essentially identical to the
procedure and equipment used to produce 54% P2O5 phosphoric
acid from 26-30% P205 strength acid.
Concentration of 54% P2O5 acid to a 68-72% P2O5 strength is
performed in vessels which use high pressure (450-550 psig)
steam or externally heated Dowtherm solution as the heat
energy source for evaporation of water from the acid. These
units effect evaporation by circulating acid at a high
volume rate consecutively through a shell and tube heat
exchanger and a flash chamber under low absolute (vacuum)
pressure conditions. In the heat exchanger, steam or
Dowtherm solution is applied to the shell side and acid
flows through tubes. Acid flow through the tubes is of the
wetted wall type rather than full tube flow. The flash
chamber serves to provide a large liquid surface area where
water vapor is released without significant acid entrainment
loss. Fluorine removal from the acid occurs concurrently
with the water vapor release. Both of these gases pass to a
barometric condenser and are absorbed in the condenser
water. Dependent upon the quality of superphosphoric acid
being produced (e.a. 30 or 50-60% conversion to
polyphosphates), either a single unit or a series of two
units may be used to accomplish the evaporation and/or
defluorination required.
DEFLUORINATED ACID - SUBMERGED COMBUSTION
A second method of phosphoric acid defluorination is by the
direct contact of hot combustion gases with the acid. In
this method a combustion chamber fitted with one or more
fuel oil or gas burners is mounted directly on top of an
acid containment chamber. Pressurized hot gases from the
fuel combustion are bubbled through the acid to an immersion
depth of up to approximately 46 cm (18 inches). Acid in the
containment chamber is maintained at a constant level by
control of the low concentration feed acid flow. Evaporated
and defluorinated product acid from the unit is continuous
and is controlled by acid boiling point and/or temperature.
Gases (evaporated water, stripped hydrogen fluoride and
silcon tetrafluoride) from the evaporation chamber flow to a
series of gas cleaning and absorption equipment. First,
entrained phosphoric acid is recovered from the gas stream
and re-introduced to the unit or to the phosphoric acid
plant. Following acid removal, the gases pass to a multi-
stage direct contact condenser system where a high
percentage of the contaminants are removed before exhaust to
31
-------
the atmosphere. Water can be used in all or only the final
stages of the condenser system as a condensing and scrubbing
medium.
DELUORINATED ACID - AERATION
This method of defluorinating phosphoric acid is the most
recent proprietary method to come into commercial use.
Relatively small quantities of diatomaceous silica or spray
dried silica gel with high surface area characteristics are
mixed with commercial 54% P2O5 phosphoric acid. This silica
material addition serves to supply sufficient silica for
conversion of the minor quantity of hydrogen fluoride (HF)
present in the impure phosphoric acid to fluosilicic acid
(H2SiF6). Fluosilicic acid at an adequate temperature in
turn breaks down to SiF4 and by simple aeration is stripped
from the heated mixture. The gaseous effluent stream is
maintained above its dew point until it enters the gas
scrubbing unit. At this point the gas stream is contacted
with water to remove contaminants before release to the
atmosphere. Phosphoric acid (54% P2O5) can be defluorinated
to a weight ratio of 100 to 1 or better P to F by this
method.
Defluprinated Phosphoric Acid - Waste Characterization
Information on water usage and effluents was obtained on two
of the three defluorination methods described, namely,
Defluorinated Acid - Vacuum Type Evaporation and
Defluorinated Acid - Submerged Combustion. No commercial
operating data or sampling information was obtained on the
Defluorinated Acid - Aeration method. This method of
defluorination has been commercial for a relatively short
time and patent protection had not yet been granted either
the original inventor or the licensee on his additional
modifications. As a result of this situation no detailed
information was attainable on this process. It is known
however, that the method's usage is confined to removal of
air contaminants from the gaseous effluent stream and
possibly a minor quantity of process water for seal water
use. Both of these usages will qualitatively and
quantitatively be equal to or less than those indicated for
the other two methods.
The following types of water usage and effluents were
identified:
A. Contaminated Water
32
-------
B. Water Supply
C. Spills and Leaks
Each of the above listed items are further identified below
as to flow and contaminant content under their respective
headings.
A. Contaminated Water
The only significant water usage in these defluorinated
acid methods is for use in scrubbing contaminants from
the gas effluent streams. The scrubber equipment may be
in the form of either a barometric condenser or the more
conventional gas scrubber type. In either case, the
instantaneous water requirement is of appreciable
magnitude. As in the defluorinated phosphate rock, the
process conditions do permit use of contaminated water
for this service. Water quality is essentially the same
as in fertilizer process circulation systems and at some
plants is actually part of that system. Contaminant
levels are dependent on such items as rainfall, extent
and degree of water treatment (if any) , and the
multiplicity of plants (if any) that use contaminated
water from the same circulation system. A water
analysis obtained from a Plant D sample during the
survey is typical of contaminated water used in
defluorinated acid process units.
Contaminated Water Constituents
Parameter Concentration
PH 1-29
Total Suspended Solids 30.00 mg/1
Total Solids 28,810.00 mg/1
Chloride (Cl) 65.00 mg/1
Sulfate (SC4) 4,770.00 mg/1
Calcium (Ca) 1,700.00 mg/1
Magnesium (Mg) 106.00 mg/1
Aluminum (Al) 260.00 mg/1
Iron (Fe) 180.00 mg/1
Fluorine (F) 967.00 mg/1
Arsenic (As) 0.83 mg/1
Zinc (Zn) 5.30 mg/1
Total Phosphorus (P) 5,590.00 mg/1
BOD5 15.00 mg/1
COD 306.00 mg/1
Color #120 (after filter)*
33
-------
Turbidity 45 Jackson Candle Units
* Unit of color - potassium chloroplatinate
The following figures indicate a representative water usage.
These figures will vary within reasonable limits between
plants and at different seasons of the year but are
representative of the magnitude required in the process.
Method 1/kkg jgal/tgn^
Defluorinated Acid - 70,510 16,900
Vacuum Type Evaporation
Defluorinated Acid - 18,024 4,320
Submerged Combustion
B. Water Supply
Water supply water is defined as uncontaminated water from
such sources as wells and commercial or municipal water
systems. The water is used for pump seal water. Usage
figures are listed below:
Method 1/kkg Igal/tonl
All Methods 43 14
C. Spills and Leaks
Spills and leaks are collected as part of process efficiency
and housekeeping. Sources of this water are pump seals and
plant wash up. The quantity is minor and/or periodic.
SODIUM PHOSPHATE - PROCESS DESCRTPTTDN
General
The high quality standards set by detergent manufacturers
for their products necessitates that an essentially pure
sodium phosphate solution be used as a raw material. This
high purity standard has greatly limited the use of wet
process phosphoric acid as a phosphate source for this
industry. One U. S. manufacturer however, does commercially
purify wet process acid to the degree necessary to allow its
use in the manufacture of sodium phosphate compounds for
detergent manufacture.
34
-------
Wet process acid contains an appreciable number and quantity
of impurities which must be removed to achieve the
acceptable detergent purity requirements. The more
significant impurities to be removed include excess sulfuric
acid, sodium fluosilicate, iron phosphate, aluminum
phosphate and calcium sulfate. Many of the process pro-
cedures and techniques used for removal of these impurities
are regarded to be trade secrets.
Sodium Phosphates - Process Description
Removal of impurities from the wet process acid used in this
process begins with the phosphate rock used in the acid
manufacture. Calcined phosphate rock is used in the
acidulation step to yield a nearly colorless acid to start
the purification steps. Rock calcination destroys the
organic matter inherent in mined rock. It is organic matter
which causes the brown coloration that normally
characterizes wet process phosphoric acid.
After the initial 20-25% P2O5 acid is produced, the acid is
treated in a series of separate neutralization steps to
individually remove the various acid impurities. The first
partial neutralization with recycled sodium phosphate liquor
is designed to remove the fluosilicates. In this step
granular sodium fluosilicate is precipitated and removed
from the acid solution by filtration. This precipitate has
commercial value as 98-9956 sodium silicofluoride (Na2SiF6) .
The next step consists of adding sodium sulfide to the
remaining solution to precipitate the minor quantity of
arsenic present. Concurrently with this precipitation,
barium carbonate can be added to remove the excess sulfate
present as barium sulfate. Barium carbonate is not used at
the plant producing sodium phosphates at the present time.
Precipitates are now removed by another filtration step.
The quantity of precipitate is small and is disposed of as
solid waste. Local landfill authorities should be notified
of the arsenic component.
At this point the partially neutralized acid still contains
iron and aluminum phosphates, and some residual fluorine. A
second neutralization is now made with soda ash to an
approximate 4.0 pH level. This induces precipitation of
essentially all the remaining impurities. These
precipitated impurities are both quite voluminous and
difficult to separate from the remaining solution. Special
techniques of heating, agitation, and retention are
necessary to adequately condition the slurry so that a
35
-------
filtration separation of the impurities can be made. These
impurities contain a relatively high quantity of P2O5 (40-
50%) and have value as a fertilizer material. Following
th 1 S no 11-hi-a 1 i -»3-4- -i «-»-» r-,4-^ ^ j_i_ _ • • -, . . . "
, —_uu „_ ^i j.t:j. I_JLJLJ.^,ci nidtez.lax. rOllO
this neutralization step, the remaining solution
sufficiently pure for the production of monoso
phosphate
is
monosodium
Monosodium phosphate is crystallized from the purified
solution by concentrating the solution in an evaporator.
The monosodium crystals, with further dehydration,
neutralization and crystallization, can be converted to such
°uheru comP°unds as sodium meta phosphate, disodium
phosphate, and tri-sodium phosphate. The several chemical
equations and steps involved in this process are indicated
on the process flowsheet.
Water effluents from these different processes are from
spills and leaks, filtration washes, and gas scrubber
liquors.
Sodium Phosphates - Waste_characterization
The survey of this process was limited by the same type of
conditions and for the same reason which existed in the
defluorinated phosphate rock process. This was that many of
the various unit operations are considered trade secret and
therefore plant access was necessarily limited to
observations of effluent streams external to the process
buildings. As previously stated, from a practical
standpoint this restricted access takes nothing away from
the value of the study other than background information and
a better understanding of the overall process water balance.
On those items which were basic and important to the study,
the industry cooperation and response to information
requests was excellent. The installed process effluent
measurement and monitoring facilities were found to be well
developed and maintained.
The following types of water usage and effluents were
identified.
A. Water Supply
B. Contaminated Effluent
C. Spills and Leaks
D. Non-Point Source Discharges
Each of the above listed items are further identified below
as to flow and contaminant content.
36
-------
A. Water Supply
Water supply is defined as uncontaminated water from
wells. The water is used for pump seal water and in
various product filtration and washing procedures.
Usage figures are listed below.
kkg (gal/ton)^
9992-12349 2395-2960
B. Contaminated Effluent
This effluent is essentially the used process water with
impurities that were added from the process function in
which it was used. An effluent analysis typical of an
effluent sample from Plant E is listed below.
Contaminated Water^Constituents
Parameter Concentration
pH 7.8
Total Suspended Solids 460 mg/1
Total Solids 2100 mg/1
Chloride (Cl) 90 mg/1
Sulfate (SO4) 240 mg/1
Calcium (Ca) 95 mg/1
Fluorine (F) 15.0 mg/1
Total Phosphorus (P) 250 mg/1
BOD5 31.0 mg/1
COD 55.0 mg/1
Temperature 78°F
The following figures represent the range of water effluent
guantities found.
1/kkg (gal/ton)
7640-10013 1830-2400
C. Spills and Leaks
The guantity of this effluent is minor and is directed
into the overall waste sewer system as part of the
contaminated effluent.1 Leaks from pumps are normal in
chemical manufacturing. Considerable effort is required
to bring under control. The use of reliable pumps, with
a serviceable packing component, and diligent servicing
schedules in all points that may develop leaks are vital
37
-------
factors for limiting waste water discharge. Where
possible, spills and leaks must be recycled and
converted to product.
D. Non-Point Source^Discharge
The origin of this discharge is primarily dry product
which dusts over the plant area from conveying
equipment. This product is periodically solubilized by
rain or melting snow and collected by the plant waste
sewer system. In this process the non-point discharge
is considered to be a significant periodic influence on
the plant effluent contaminant level.
E. The raw waste loads are summarized below:
Defluorinated Phosphate Rock
Flow: 46,000 1/kkg (11,000 gal/ton)
Total Phosphorus (P) 600 mg/1
Fluoride (F) 1930 mg/1
TSS 16 mg/1
pH 1.65
Defluorinated Phosphoric Acid
Flow: Vacuum Type Evaporation 70,500 1/kkg (16,900 gal/ton)
Submerged Combustion 18,000 1/kkg (4,300 gal/ton)
Total Phosphorus (P) 5590 mg/1
Fluoride (F) 967 mg/1
TSS 30 mg/1
pH 1.29
Sodium Phosphates
Flow: 7,600 - 10,000 1/kkg (1,830 - 2,400 gal/ton)
Total Phosphorus (P) 250 mg/1
Fluoride (F) 15 mg/1
TSS 460 mg/1
pH 7.8
38
-------
DEFLUORINATED PHOSPHATE ROCK
Phosphate
Rock
FLUID BED PROCESS
Phos-
phoric
Acid
Other
Def luori-
nating
Reagents
4 *
Non-Agglomer
Feed
Fluidizing Gas
W V It
Mixer
v
Dryer
V
Screen
atedw
Heater
To
Make Up Water . Atmo-phcrc
877 1/kkg * f OAtmo_phcrc
ziu cf/s . L . .,.*,-. cuiH-aiuj.na Ltiu
4k p v Water
Effluent Gas ^ Sciubbei.
^ &
P.yr 1 nnp
Fluid V/ V
Bed Y Contaminated
Reactor I Water to
p __ ^bust uctcntion
Y^ ' Recycle Pond
y 45,894 1/kkg
Agglomerated and 11,000 g/s.t.
Def luorinated
Phosphate
Product
Figure V-I
-------
DEFLUORINATED PHOSPHORIC ACID - VACUUM PROCESS
(Super Phosphoric)
Water Water
Water
54% Phos-
phoric Acid
No. 1
Evapo-
rator
I
Shipping
T ~ i "
^ 1 'gy
L ,
No. 2
Evapo-
rator
i
rfl
Pump
Product
Cooler
To Cooling Pond
70,510 1/kkg
16,900 g/s.t.
Pump
Alternate Heat
Medium
I
Alternate Heat Medium
I I
" ._ — i Combustion
T Gases
Fuel
Process
Water
43 lAkg
14 g/s.t.
Figure V-2
-------
DEFLUORINATED PHOSPHORIC ACID
(Submerged Combustion)
Gas
Air
54% P2O5
Feed Acid
Burner
I Dip Tube i
Evaporator
Scrubber
Gas
Cooler
Superphosphoric
Acid
(To shipping)
Acid
Cooler
ra-
1
&
V
«—
Air cooler
To Cooling
Pond
43 1/kkg
14 g/s.t.
Weak Acid
(To phos.
0 Acid
Plant)
Product
Pump
And Sludge
Tank
Scrubber
Tank
Figure V-3
-------
DEFLUORIN'ATED ACID - AERATION TYPE
Process
Water
Silica
Contaminated
Water
To
Atmosphere
545'=
Phosphoric
P205
Acid
Contaminated Water
Pond
Steam
Heat
Exchanger
>Condensate Return
Circulation Pump
Product to
Shipping
Figure V - 4
-------
Wet Process Phosphoric Acid
SODIUM PHOSPHATE PROCESS
FROM WET PROCESS
PHOSPHORIC ACID
MONO SODIUM
PHOSPHATE
T
SODIUM
META PHOSPHATE
7640-10013 1/kkg
(1830-2400 gal/s.t.)
DISODIUM PHOSPHATE
DUOHYDRATE OR
ANHYDROUS
DISODIUM PHOSPHATE
CRYSTAL
TETRA SODIUM PYRO
PHOSPHATE
Figure V-S
-------
SECTION VI
SELECTION OF POLLUTANT PARAMETERS
General
The selection of pollutant parameters was a necessary early
step of the study. Collection of meaningful data and
sampling was dependent on knowing what fertilizer process
contaminants are important so far as degradation of natural
water resources are concerned.
The general criteria considered and reviewed in the
selection of pollutant parameters included:
- quality of the plant intake water
- products manufactured
- raw materials used
environmental harmfulness of the compounds or elements
included in process effluent streams
Qther^Non-Fertilizer Phosphate^Chemicals
Effluent waste waters from the three processes included in
this survey are similar to those associated with the
phosphate fertilizer industry. The primary factors and
contaminants to be controlled to achievable levels are:
suspended solids, pH, phosphorus and fluorides.
Radium 226 is considered to be a very important raw waste
load component. Radium 226 coprecipitates with most
sedimentary fractions, particularly at a reasonably high pH
level. The pH 6.0 to 9.0 range set for effluent discharges,
along with the limitations as suspended solids, deals
effectively with the effluent problem. The Environmental
Protection Agency has ongoing studies and is initiating new
studies on the problem of radium-226 in gypsum pond waters.
Such studies indicate that double lime treatment to a pH
range of 6.0 to 9.0 is required to achieve optimum removal
of radium-226. Additional information obtained from these
studies will be evaluated, and where appropriate, current
effluent guidelines may be amended. Procedures currently
proposed are judged to be adequate and provide for rigorous
control of radium-226. A more detailed discussion of this
problem can be found in references N and 0.
45
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Secondary parameters which should be monitored but do not
warrant definitive guidelines are: temperature, . total
dissolved solids, chemical oxygen demand (COD), arsenic, and
cadmium. The prime reason for not setting guidelines for
these secondary parameters is that treatment for the primary
parameters will effect removal of also the secondary ones.
A considered additional reason is that insufficient data
exists from which to establish responsible guidelines.
Selection of these parameters is justified by the fact that
best available technology economically achievable as well as
best demonstrated technology is in current commercial use.
Rationale for Selection of Parameters
Temperature
Temperature is one of the most important and influential
water quality characteristics. Temperature determines those
species that may be present; it activates the hatching of
young, regulates their activity, and stimulates or
suppresses their growth and development; it attracts, and
may kill when the water becomes too hot or becomes chilled
too suddenly. Colder water generally suppresses
development. Warmer water generally accelerates activity
and may be a primary cause of aquatic plant nuisances when
other environmental factors are suitable.
Temperature is a prime regulator of natural processes within
the water environment. It governs physiological functions
in organisms and, acting directly or indirectly in
combination with other water quality constituents, it
affects aquatic life with each change. These effects
include chemical reaction rates, enzymatic functions,
molecular movements, and molecular exchanges between
membranes within and between the physiological systems and
the organs of an animal.
Chemical reaction rates vary with temperature and generally
increase as the temperature is increased. The solubility of
gases in water varies with temperature. Dissolved oxygen is
decreased by the decay or decomposition of dissolved organic
substances and the decay rate increases as the temperature
of the water increases reaching a maximum at about 30°C
(86°F). The temperature of stream water, even during
summer, is below the optimum for pollution-associated
bacteria. Increasing the water temperature increases the
bacterial multiplication rate when the environment is
favorable and the food supply is abundant.
46
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Reproduction cycles may be changed significantly by
increased temperature because this function takes place
under restricted temperature ranges. Spawning may not occur
at all because temperatures are too high. Thus, a fish
population may exist in a heated area only by continued
immigration. Disregarding the decreased reproductive
potential, water temperatures need not reach lethal levels
to decimate a species. Temperatures that favor competitors,
predators, parasites, and disease can destroy a species at
levels far below those that are lethal.
Fish food organisms are altered severely when temperatures
approach or exceed 90°F. Predominant algal species change,
primary production is decreased, and bottom associated
organisms may be depleted or altered drastically in numbers
and distribution. Increased water temperatures may cause
aquatic plant nuisances when other environmental factors are
favorable.
Synergistic actions of pollutants are more severe at higher
water temperatures. Given amounts of domestic sewage,
refinery wastes, oils, tars, insecticides, detergents, and
fertilizers more rapidly deplete oxygen in water at higher
temperatures, and the respective toxicities are likewise
increased.
When water temperatures increase, the predominant algal
species may change from diatoms to green algae, and finally
at high temperatures to blue-green algae, because of species
temperature preferentials. Blue-green algae can cause
serious odor problems. The number and distribution of
benthic organisms decreases as water temperatures increase
above 90°F, which is close to the tolerance limit for the
population. This could seriously affect certain fish that
depend on benthic organisms as a food source.
The cost of fish being attracted to heated water in winter
months may be considerable, due to fish mortalities that may
result when the fish return to the cooler water.
Rising temperatures stimulate the decomposition of sludge,
formation of sludge gas, multiplication of saprophytic
bacteria and fungi (particularly in the presence of organic
wastes), and the consumption of oxygen by putrefactive
processes, thus affecting the esthetic value of a water
course.
In general, marine water temperatures do not change as
rapidly or range as widely as those of freshwaters. Marine
and estuarine fishes, therefore, are less tolerant of
47
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temperature variation. Although this limited tolerance is
greater in estuarine than in open water marine species,
temperature changes are more important to those fishes in
estuaries and bays than to those in open marine areas,
because of the nursery and replenishment functions of the
estuary that can be adversely affected by extreme
temperature changes.
E3* Acidity and Alkalinity
Acidity and alkalinity are reciprocal terms. Acidity is
produced by substances that yield hydrogen ions upon
hydrolysis and alkalinity is produced by substances that
yield hydroxyl ions. The terms "total acidity" and "total
alkalinity" are often used to express the buffering capacity
of a solution. Acidity in natural waters is caused by
carbon dioxide, mineral acids, weakly dissociated acids, and
the salts of strong acids and weak bases. Alkalinity is
caused by strong bases and the salts of strong alkalies and
weak acids.
The term pH is a logarithmic expression of the concentration
of hydrogen ions. At a pH of 7, the hydrogen and hydroxyl
ion concentrations are essentially equal and the water is
neutral. Lower pH values indicate acidity while higher
values indicate alkalinity. The relationship between pH and
acidity or alkalinity is not necessarily linear or direct.
Waters with a pH below 6.0 are corrosive to water works
structures, distribution lines, and household plumbing
fixtures and can thus add such constituents to drinking
water as iron, copper, zinc, cadmium and lead. The hydrogen
ion concentration can affect the "taste" of the water. At a
low pH water tastes "sour". The bactericidal effect of
chlorine is weakened as the pH increases, and it is
advantageous to keep the pH close to 7. This is very
significant for providing safe drinking water.
Extremes of pH or rapid pH changes can exert stress
conditions or kill aquatic life outright. Dead fish,
associated algal blooms, and foul stenches are aesthetic
liabilities of any waterway. Even moderate changes from
"acceptable" criteria limits of pH are deleterious to some
species. The relative toxicity to aquatic life of many
materials is increased by changes in the water pH.
Metalocyanide complexes can increase a thousand-fold in
toxicity with a drop of 1.5 pH units. The availability of
many nutrient substances varies with the alkalinity and
acidity. Ammonia is more lethal with a higher pH.
48
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The lacrimal fluid of the human eye has a pH of
approximately 7.0 and a deviation of 0.1 pH unit from the
norm may result in eye irritation for the swimmer.
Appreciable irritation will cause severe pain.
Total Suspended Solids
Suspended solids include both organic and inorganic
materials. The inorganic components include sand, silt, and
clay. The organic fraction includes such materials as
grease, oil, tar, animal and vegetable fats, various fibers,
sawdust, hair, and various materials from sewers. These
solids may settle out rapidly and bottom deposits are often
a mixture of both organic and inorganic solids. They
adversely affect fisheries by covering the bottom of the
stream or lake with a blanket of material that destroys the
fish-food bottom fauna or the spawning ground of fish.
Deposits containing organic materials may deplete bottom
oxygen supplies and produce hydrogen sulfide, carbon
dioxide, methane, and other noxious gases.
In raw water sources for domestic use, state and regional
agencies generally specify that suspended solids in streams
shall not be present in sufficient concentration to be
objectionable or to interfere with normal treatment
processes. Suspended solids in water may interfere with
many industrial processes, and cause foaming in boilers, or
encrustations on equipment exposed to water, especially as
the temperature rises. Suspended solids are undesirable in
water for textile industries; paper and pulp; beverages;
dairy products; laundries; dyeing; photography; cooling
systems, and power plants. Suspended particles also serve
as a transport mechanism for pesticides and other substances
which are readily sorbed into or onto clay particles.
Solids may be suspended in water for a time, and then settle
to the bed of the stream or lake. These settleable solids
discharged with man's wastes may be inert, slowly
biodegradable materials, or rapidly decomposable substances.
While in suspension, they increase the turbidity of the
water, reduce light penetration and impair the
photosynthetic activity of aquatic plants.
Solids in suspension are aesthetically displeasing. When
they settle to form sludge deposits on the stream or lake
bed, they are often much more damaging to the life in water,
and they retain the capacity to displease the senses.
Solids, when transformed to sludge deposits, may do a
variety of damaging things, including blanketing the stream
or lake bed and thereby destroying the living spaces for
49
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those benthic organisms that would otherwise occupy the
habitat. When of an organic and therefore decomposable
nature, solids use a portion or all of the dissolved oxygen
available in the area. Organic materials also serve as a
seemingly inexhaustible food source for sludgeworms and
associated organisms.
Turbidity is principally a measure of the light absorbing
properties of suspended solids. It is frequently used as a
substitute method of quickly estimating the total suspended
solids when the concentration is relatively low.
Fluorides
As the most reactive non-metal, fluorine is never found free
in nature but as a constituent of fluorite or fluorspar,
calcium fluoride, in sedimentary rocks and also of cryolite,
sodium aluminum fluoride, in igneous rocks. Owing to their
origin only in certain types of rocks and only in a few
regions, fluorides in high concentrations are not a common
constituent of natural surface waters, but they may occur in
detrimental concentrations in ground waters.
Fluorides are used as insecticides, for disinfecting brewery
apparatus, as a flux in the manufacture of steel, for
preserving wood and mucilages, for the manufacture of glass
and enamels, in chemical industries, for water treatment,
and for other uses.
Fluorides in sufficient quantity are toxic to humans, with
doses of 250 to 150 mg giving severe symptoms or causing
death.
There are numerous articles describing the effects of
fluoride-bearing waters on dental enamel of children; these
studies lead to the generalization that water containing
less than 0.9 to 1.0 mg/1 of fluoride will seldom cause
mottled enamel in children, and for adults, concentrations
less than 3 or 4 mg/1 are not likely to cause endemic
cumulative fluorosis and skeletal effects. Abundant
literature is also available describing the advantages of
maintaining 0.8 to 1.5 mg/1 of fluoride ion in drinking
water to aid in the reduction of dental decay, especially
among children.
Chronic fluoride poisoning of livestock has been observed in
areas where water contained 10 to 15 mg/1 fluoride.
Concentrations of 30 - 50 mg/1 of fluoride in the total
ration of dairy cows is considered the upper safe limit.
Fluoride from waters apparently does not accumulate in soft
50
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tissue to a significant degree and it is transferred to a
very small extent into the milk and to a somewhat greater
degree into eggs. Data for fresh water indicate that
fluorides are toxic to fish at concentrations higher than
1.5 mg/1.
Phosphorus
During the past 30 years, a formidable case has developed
for the belief that increasing standing crops of aquatic
plant growths, which often interfere with water uses and are
nuisances to man, frequently are caused by increasing
supplies of phosphorus. Such phenomena are associated with
a condition of accelerated eutrophication or aging of
waters. It is generally recognized that phosphorus is not
the sole cause of eutrophication, but there is evidence to
substantiate that it is frequently the key element in all of
the elements required by fresh water plants and is generally
present in the least amount relative to need. Therefore, an
increase in phosphorus allows use of other, already present,
nutrients for plant growths. Phosphorus is usually
described, for this reasons, as a "limiting factor."
When a plant population is stimulated in production and
attains a nuisance status, a large number of associated
liabilities are immediately apparent. Dense populations of
pond weeds make swimming dangerous. Boating and water
skiing and sometimes fishing may be eliminated because of
the mass of vegetation that serves as an physical impediment
to such activities. Plant populations have been associated
with stunted fish populations and with poor fishing. Plant
nuisances emit vile stenches, impart tastes and odors to
water supplies, reduce the efficiency of industrial and
municipal water treatment, impair aesthetic beauty, reduce
or restrict resort trade, lower waterfront property values,
cause skin rashes to man during water contact, and serve as
a desired substrate and breeding ground for flies.
Phosphorus in the elemental form is particularly toxic, and
subject to bioaccumulation in much the same way as mercury.
Colloidal elemental phosphorus will poison marine fish
(causing skin tissue breakdown and discoloration). Also,
phosphorus is capable of being concentrated and will
accumulate in organs and soft tissues. Experiments have
shown that marine fish will concentrate phosphorus from
water containing as little as 1 ug/1.
Radioactivity
51
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Ionizing radiation, when absorbed in living tissue in
quantities substantially above that of natural background
levels, is recognized as injurious. It is necessary,
therefore, to prevent excessive levels of radiation from
reaching any living organism humans, fishes, and
invertebrates. Beyond the obvious fact that radioactive
wastes emit ionizing radiation, they are also similar in
many respects to other chemical wastes, Man's senses cannot
detect radiation unless it is present in massive amounts.
Plants and animals, to be of any significance in the cycling
of radionuclides in the aquatic environment, must accumulate
the radionuclide, retain it, be eaten by another organism,
and be digestible. However, even if an organism accumulates
and retains a radionuclide and is not eaten before it dies,
the radionuclide will enter the "biological cycle" through
organisms that decompose the dead organic material into its
elemental components. Plants and animals that become
radioactive in this biological cycle can thus pose a health
hazard when eaten by man.
Aquatic life may receive radiation from radionuclides
present in the water and substrate and also from
radionuclides that may accumulate within their tissues.
Humans can acquire radionuclides through many different
pathways. Among the most important are through drinking
contaminated water, and eating fish and shellfish that have
concentrated nuclides from the water. Where fish or other
fresh or marine products that have accumulated radioactive
materials are used as food by humans, the concentrations of
the nuclides in the water must be further restricted, to
provide assurance that the total intake of radionuclides
from all sources will not exceed the recommended levels.
In order to prevent unacceptable doses of radiation from
reaching humans, fish, and other important organisms, the
concentrations of radionuclides in water, both fresh and
marine, must be restricted.
Radium-226
Radium-226 is one of the most hazardous radioisotopes of the
uranium decay scheme, when present in water. The human body
preferentially utilizes radium in lieu of calcium when
present in food or drink. Plants and animals concentrate
radium, leading to a multiplier effect up the food web.
Radium-226 decays by alpha emission into radon-222, a radio-
active gas with a half life of 3.8 days. The decay products
of radon-222, in turn, are particulates which can be
52
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adsorbed onto respirable particles of dust. Radon and its
decay products has been implicated in an increased incidence
of lung cancer in those workers exposed to high levels
(Bureau of Mines, 1971). Heating or grinding of phosphate
rock would liberate radon and its decay products to the
surrounding atmosphere.
It is generally agreed that unlike other materials, there is
no threshold value for radiation exposure. Accordingly, the
Federal Radiation Council has repeatedly stated that all
radiochemical material releases are to be kept to the
minimum practicably obtainable. The Council states "It
should be general practice to reduce exposure to radiation,
and positive efforts should be carried out to fulfill the
sense of these recommendations. It is basic that exposure
to radiation should result from a real determination of its
necessity (Federal Radiation Council, I960)."
METHODS OF ANALYSIS
The methods of analysis to be used for guantitative
determination are given in the Federal Register 40 CFR 136
for the following parameters pertinent to this study:
Alkalinity (and Acidity)
fluoride
oxygen demand, chemical
phosphorus
solids, total
suspended nonfilterable solids, total
temperature
53
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
The factors and contaminants in non-fertilizer phosphate
chemical process effluent streams have for the most part
been well identified and well known for many years. As a
consequence considerable effort has been expended to correct
or minimize the majority of those which are particularly
detrimental to natural water receiving bodies. Much of this
work has been directed at correcting the source of the
contamination or an in-process improvement rather than an
end-ofpipe type of treatment. A large part of the
motivation for such improvement has been economics - that
is, improved operating efficiency and costs. Such
improvements are just plain good business and justify
capital expenditure required to achieve them.
With an appreciation of the above mentioned facts, the
following criteria were established as bases for
investigating treatment technology.
- To determine the extent of existing waste water control
and treatment technology
To determine the availability of applicable waste water
control and treatment technology regardless of whether it be
intra-industry transfer technology
- To determine the degree of treatment cost reasonability
Based upon these stated criteria the effort was made to
factually investigate overall treatment technologies dealing
with each of the primary factors and contaminants listed in
Section VI.
Process technology does exist both for containment and for
treatment and reduction of the primary factors and
contaminants present in the non-fertilizer phosphate
chemical processes as defined in Section VI. These have
been divided into two separate technologies to make them
better adaptable to all the processes. For example, in two
of the processes it is very possible that both technologies
need to be used and therefore be considered as a single
treatment method. In another process however it would be
somewhat impractical to consider using more than one of the
technologies although they are closely inter-related. These
two technologies are therefore described separately even
though it is recognized that they may be essentially
integral in some cases.
55
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Containment and Cooling Pond
The title provides a reasonably good description of this
technology. That is, it is simply an area where the
contaminated effluent is contained in sufficient guantity
and for a sufficient time to satisfy the process conditions.
The process conditions alluded to are instantaneous volume
needs and temperature reduction or cooling. Due to the fact
that individual process requirements essentially dictate the
area required it is not possible to be more specific. An
indication of the land area used for this purpose is shown
by the fact that survey plant A utilizes approximately 0.11
hectare (0.26 acre) per daily production ton. This figure
also includes area adequate to contain excessive rainfall
collection until normal conditions can be restored.
Factors in Pond Construction and Management that Provide
Pond Reliability and Efficiency of Operation
A. Prevention of Dike Failure
Dike failure has been by far the greatest cause of navigable
water contamination from phosphate mining operations. Many
slime pond dike failures have occurred. These have caused
massive contamination of surface waters.
A similar potential hazard exists from gyp-pond and
recirculation cooling pond dikes, although these are
generally much smaller structures than the slime pond dikes.
Gypsum derived from total manufacturing and waste water
treatment practices is the only dike material readily
available at many sites. It is not an ideal material for
construction of dams. A dam constructed entirely of gypsum
has a uniform and relatively high permeability. Water seeps
through the structure. Saturation is maintained in much of
the dam mass unless special provision is made for drainage
of the toe. Some States maintain a degree of regulation of
dikes. The State of Illinois requires some underdrainage of
gyp-pond dikes at Joliet, Illinois.
A saturated dam is weakened in a number of ways. Piping
occurs in the outer toe. The water in the dam buoys the
structural material, reducing the dikes effective weight.
Granular materials saturated with water will become
momentarily fluid if an earthquake or a shock wave of any
type sets up a tremor.
Hazardous conditions are common in gyp-pond dams. The
contractors diagram of a typical dam, supplied with this
study, indicates, no provision of underdrainage. The lack
56
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of specifications that make dikes safe, and/or the lack of
enforcement of these specifications can lead to dike
failures.
A gyp-pond or recirculation pond dike must be constructed in
a manner that maintains effective drainage in the outer half
of the dike. If gypsum is the sole material in the dike, a
farm tile (or other equally effective) underdrainage system
should be provided in the toe of the dike. The tile lines
must be close enough together, located below sufficiently
permeable liner materials and sloped adequately. The tile
field must remain operational and drain effectively
throughout the entire period of waste water containment.
The engineering details of any new gyp-pond utilized for
treating the waste water in the other non-fertilizer
phosphate chemicals segment of the phosphate manufacturing
should be submitted to and approved by EPA prior to use.
In the event of declining efficiency of a drainage system,
relief wells should be provided to maintain the drainage
function.
Both a relief well system or a farm tile underdrainage
system leading to an underground sump have many advantages
over the open ditches commonly utilized to catch seepage.
The underground systems permit return of seepage without
lowering the outer edge of the dam. This strongly favors
dike safety. The ditch alone provides none of the
underdrainage required to make the dam safe.
An inherent advantage of the underground sump or relief well
system is that seepage can be returned to the lagoon free of
rain run-off water. No ditch is provided (or essential) to
collect this run-off.
Planting the dam slopes with low plants can be utilized to
improve the water balance and to stabilize the dam surface.
Tall plants that reduce wind velocity over the pond surface
must be avoided, wind is an aid to cooling.
The U.S. Department of Interior, Bureau of Reclamation, book
"Design of Small Dams" presents discussions and diagrams of
toe draining systems, with a horizontal drainage blanket, an
underground drainage trench, and an underground pipe conduit
leading to an outfall. This system can readily replace the
open seepage interceptive ditch in common use. The
intercepted seepage can be pumped back to the pond from an
underground sump. This system does not return runoff from
outer slopes to the lagoon.
57
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The reliability of a properly installed underground drainage
system is extremely high. A soundly designed system assures
a safe dam for its full service life.
If some local factor introduces a reliability problem two
control measures should be considered:
1. Install a conduit to the top altitude of the drain
system for periodic drain pipe flushing to prevent
plugging.
2. Install a vertical permeable pipe at the center of the
damf through which the phreatic line may be measured.
The design engineer should specify the maximum safe
height of this phreatic line for each dam.
New ponds for BPCTCA should have underdrainage systems to
eliminate the need to recycle rainfall on the outer slope
and seepage interceptor ditch. These ponds require only
freeboard for containing the heaviest expected rain in 10
years. The freeboard requirement changes abruptly to be
sufficient to hold the heaviest expected rain in 25 years in
1983. From practical considerations, it may be advisable to
provide the 25 year freeboard in a new pond to avoid an
alteration problem before 1983.
B. Control of Seepage
A pond, to be acceptable for use in waste water treatment,
should be provided with a liner that prevents significant
percolation to ground water, and that blocks flow to
groundwater through underground channels. Furthermore, any
waste water seepage must have no solution action on
underlying layers. It is particularly important to prevent
acidic waste water seepage through limestone formations.
Some liming may be required, particularly at start-up, to
protect limestone layers, to provide sediment for plugging
of the bottom liner, and to prevent seepage of fluoride,
radium-226 and phosphate components.
Relief wells, underdrainage or other provision must be made
to prevent upflow of groundwater into the lagoon. Upflow
into a lagoon normally breaches the liner and permits flow
of waste water through existent channels to groundwater when
lagoon hydrostatic pressure exceeds the groundwater
pressure.
Groundwater monitoring by means of wells in the percolation
area should be installed whenever the lagoon is provided
with a liner of questionable impermeability. The addition
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of lime to bottom sediments in lagoons will lead to
neutralization of waste water seeping into ground water.
The use of lime will also provide sedimentary conditions
that tend to block seepage.
The liming of pond water can be utilized to aid both air
pollution control and to reduce loss of waste water
pollutants by seepage.
C. Deposits of Objectionable Substances at
Phosphate Manufacturing Plants
Various deposits of objectionable waste water components
occur in ponds or landfill areas. Examples of these are
calcium fluoride, radium-226 and arsenic sulfide. Local
State and EPA authorities with jurisdiction over this
landfill problem should be notified of the deposits and the
control measures required should then be established. It is
vital that percolating water does not carry these substances
into ground water or into surface waters.
D. Ponds in Regions with Severe Cold Seasons
The cooling problem for a reuse and cooling pond varies
drastically from summer to winter seasons in cold climates.
It is essential to install conduits underground, or
otherwise protect from freezing. Provision must be made for
isolation of a pond with a limited surface area for winter
operation. The heat discharged to the pond in normal
operation will then prevent troublesome freezing incidents.
The winter pond must be deep enough to remain operable after
a plant shutdown.
National standards are not being proposed for recirculation
and reuse ponds. Some State and local authorities have set
standards. Monitoring should cover the factors that control
loss of waste water to surface and ground waters, and local
authorities should be notified of conditions threatening
navigable and ground waters with pollution.
ContaminatedT (Pond) Water Treatment
This technology is identical to that treatment technology
designated as gypsum pond (contaminated) water treatment in
the phosphate fertilizer section of the development document
for the Basic Fertilizer Chemicals Manufacturing Industry.
The Containment and Cooling Pond technology described above
is intended to function as a no discharge closed loop system
the majority of the time. This "no discharge" situation is
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however dependent upon the quantity of rainfall it can
accept before its water storage capacity is exceeded. Once
the storage area approaches capacity it is necessary to
begin treating the contaminated water for subsequent
discharge to natural drainage areas. Similarly, in those
processes in which a containment pond is impractical it may
be necessary to continuously treat the contaminated process
effluent water. This technology in part or as a whole is
capable of treating the contaminated effluent of either the
containment pond or the process effluent streams.
Process Description
Contaminated water can be treated effectively for control of
the pollution parameters identified in Section VI, namely
suspended solids, pH, phosphorus, radium-226, and fluorides.
The treatment described is by means of either single or two-
stage lime neutralization procedure. In the Sodium
Phosphate process there are indications that only single
liming is required for removal of the impurities.
Normally two stages of liming or neutralization are
necessary to effect an efficient removal of the fluoride and
phosphate contaminants. Fluorides are present in the water
principally as fluosilicic acid with small amounts of
soluble salts as sodium and potassium fluosilicates and
hydrofluoric acid. Phosphorus is present principally as
orthophosphoric acid with some minor amounts of soluble
calcium orthophosphates in the conventional wet phosphoric
acid production process. Polyphosphates that require
special pretreatment prior to lime sedimentation may be
present in lagoons accepting waste water from defluorination
processes, and from the manufacture of defluorinated (poly)
phosphates.
The first treatment stage provides sufficient neutralization
to raise the contaminated water containing up to 9,000 mg/1
F and up to 6,500 mg/1 P from pH 1-2 to pH 3.5-4.0. The
resultant treatment effectiveness is, to a significant
degree, dependent upon the mixing efficiency at the point of
lime addition and the constancy of the pH control. At a pH
level of 3.5 to U.O, the fluorides will precipitate
principally as calcium fluoride (CaF2) as shown by the
following chemical equation.
H2SiF6 + 3 CaO + H20 = 3 CaF2 + 2 H20 + Si02
Fluosilicic Lime Water Calcium Water Silica
Acid
60
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This mixture is then held in a quiescent area to allow the
particulate CaF2 to settle.
Equipment used for neutralization ranges from crude manual
distribution of lime with localized agitation to a well
engineered lime control system with a compartmented mixer.
Similarly the quiescent areas range from a pond to a
controlled, settling rate thickener or settler. The
partially neutralized water following separation from the
CaF2, (pH 3.5-4.0) now contains 30-60 mg/1 F and up to 5,500
mg/1 P. This water is again treated with lime sufficient to
increase the pH level to 6.0 or above. At this pH level
calcium compounds, primarily dicalcium phosphate plus
additional quantities of CaF2 precipitate from solution.
The primary reactions are shown by the following chemical
equation:
2 H3PO4 * CaO * H20
Phosphoric Lime Water
Acid
Ca(H2P04)2 + CaO + H20
Monocalcium Lime Water
Phosphate
Ca(H2PO<*)2
Monocalcium
Phosphate
2CaHP04
Dicalcium
Phosphate
2 H20
Water
2 H20
Water
As before, this mixture is retained in a quiescent area to
allow the CaHPO4 and minor amounts of CaF2 to settle.
After settlement, the clear, neutralized water will contain
15-30 mg/1 F and 30-60 mg/1 P at a pH of 6-8. The reduction
of the P value is strongly dependent upon the final pH level
and quality of the neutralization facilities, particularly
mixing efficiency. Neutralization to pH levels of 9-11 will
reduce P values to 15-30 mg/1 or less. Figure VII-1 shows a
sketch of a well designed "double lime" treatment facility.
Plants B, C and D all practice some degree of liming.
61
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Some special precautions are essential at a plant producing
sodium phosphates. All meta, tetra, pyro and polyphosphate
waste water in spills should be diverted to the reuse pond.
These phosphates will not precipitate satisfactorily in the
lime treatment process and will interfere with the removal
of fluoride and suspended solids.
Polyphosphate in waste water will exert a desirable anti-
fouling action if diverted to the cooling water stream from
the reuse lagoon. Furthermore, the compound will hydrolyze
and precipitate in the lagoon.
Domestic waste, unless completely bio-oxidized, has
undesirable effects in sodium phosphate plant effluent. The
amino acids and other organic components interfere with both
precipitation and flocculation. The high calcium level of
the recycle pond is lacking in the waste water stream from
the sodium phosphate plant. Lime and/or calcium salts may
be required for acceptable removal of P and F pollutants.
Adequate precipitant reagent use must be supported by
effective clarification for control of F, P and SS.
In some circumstances it may be desirable to strip carbon
dioxide from the waste stream before lime treatment so that
carbonate does not compete with phosphate in the
precipitation reaction.
The sodium phosphates subcategory manufacturing process
utilizes a series of salting out processes for separating
various crystallized products. The resultant waste water
streams contain a variety of contaminants that cannot be
recycled in the process without degenerating product
quality. The manufacturing processes isolate some of the
potential waste water pollutants from the waste stream.
Sodium silicofluoride is precipitated out and sold as a
byproduct; this process disposes of most of the troublesome
fluoride problem. Radium 226 is segregated into various
sediment fractions. Arsenic is separated as sulfide
precipitate. Sedimentation occurs in the waste streams from
the sodium phosphate processes and the sediments are removed
by clarification. The technical details of these processes
have not been fully disclosed by the manufacturer.
A recirculation pond is available on the site for handling
difficult waste water streams to the same extent that this
lagoon system is available for defluorinated rock and acid
waste water.
Modified forms of phosphate create a unique treatment
problem at defluorination plants. Phosphoric acid and/or
62
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phosphate salts undergo polymerization and molecular
rearrangement reactions when subjected to severe dehydration
treatment. The acid defluorination treatments applied are
predominantly operated with application of heat and a gas
stripping action. These heating and/or stripping actions
induce a substantial degree of molecular conversion in the
defluorinated acids. The conversion is particularly high in
super-acid grades concentrated to a high P2^05 content.
Likewise, the high temperatures applied for rock
defluorination convert the raw orthophosphate rock to
polyphosphates.
These modified phosphates differ sharply from
orthophosphates in solubility. Calcium orthophosphates have
extremely low solubility in moderately alkaline solutions;
the calcium salts of the modified phosphates have
appreciable solubility. In fact, these modified phosphates
are applied extensively as chelating agents to combat
calcium induced hardness. These modified phosphates are
relatively stable at ambient temperatures. The half life
varies from compound to compound and is poorly defined; this
half life is commonly taken to be about 2 days in acidic
waters, but is several weeks in neutral or alkaline waters.
These modified phosphates enter the process waste water from
various sources. Stack washing introduces some dust from
rock defluorination. Spray carryover to barometric
condenser water is a common source of contamination in acid
defluorination. Spills and leaks carry polyphosphates into
waste water in all the subcategories. Rain run-off from
drying, packaging, loading and shipping areas carry these
modified phosphates into the waste water stream.
It is vitally important that waste water bearing these
modified phosphates be excluded from streams flowing to lime
treatment facilities; this is especially objectionable
without impoundment. The calcium salts of these modified
phosphates are much more soluble than the calcium
orthophosphate salts. Satisfactory phosphate precipitation
will not occur on lime treatment. Furthermore,
polyphosphates exert an objectionable interference action on
clarification processes. And still further, the soluble
calcium salts of molecular species other than orthophosphate
act as individual agents in the calcium precipitation
process. Thus, a system with only orthophosphate will
remain saturated with calcium orthophosphate. The mixed
system will remain saturated with calcium orthophosphate and
with each component calcium phosphate. The sum of the
phosphate components in solution will be higher than the
orthophosphate component alone.
63
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Where waste water contamination does occur with these
modified phosphates, the resultant waste streams, should be
directed to a special holding pond, along with acidic wastes
that speed hydrolysis. Completing of hydrolysis can be
promoted further by discharge into the contaminated water
recirculation pond. The modified phosphates continue the
hydrolysis to orthophosphate in the recirculation lagoon.
This factor adds another plus value to the desirability of
the recirculation and reuse lagoon at a phosphate facility
with defluorination processes. The holding is especially
beneficial at the typical low pH levels prevailing in
typical contaminated water ponds. Acidity hastens
hydrolysis to the orthophosphate form.
A unique condition prevails in the waste water discharge
from the single plant producing sodium phosphates. This
stream also contains the domestic waste discharge from the
septic tanks accepting the plant's domestic sewage. An
efficient aerobic bio-oxidation step applied to this waste
water would destroy most of the organic substances that
interfere with sedimentation; furthermore, this bio-
oxidation process will catalyze the hydrolysis of
polyphosphates present in the waste water to orthophosphate.
Bio-oxidation may be the most practicable means of
converting any polyphosphates present to orthophosphate in
this situation. The waste stream is neutral; hydrolysis of
polyphosphates will be extremely slow unless bio-catalytic
action is induced in the system. Many microorganisms
produce enzymes that catalyze the hydrolysis of
polyphosphates. Reference P brings out the observation that
no problem was encountered in precipitating phosphates in
domestic waste water following bio-oxidation of the waste
water.
It must be recognized that pH alone does not indicate the
total effectiveness of the precipitating reagent. The
calcium content in the pond water will also be a factor and
will vary widely. The sulfate ion competes for the calcium
ion; a high sulfate content will tend to reduce the calcium
content of a pond and create a condition relatively
unfavorable for fluoride and phosphate precipitation. The
pH change induced by lime addition, gives a general
indication of the precipitation potential in the system. A
pH rise from lime addition is accompanied by a rise in
soluble calcium content. In normal circumstances, lime to
pH 6.0 will be adequate for precipitating fluorine and
phosphate to meet required limitations, but lime will have
to be added, as required, if fluoride and phosphate
limitations are not met.
64
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Soluble iron and aluminum compounds are present at high
concentrations in many ponds. The iron and aluminum cations
exert a strong influence on phosphate precipitation.
Strong winds interfere with sedimentation in lagoons. A
covered terminal sedimentation basin, or a covered final
segment of a sedimentation basin will be indispensable for
attaining satisfactory suspended solids removal under many
conditions. A cover is particularly beneficial in periods
of cold weather. Temperature inversion currents cause
severe disturbance of sedimentation in open basins in cold
weather. Inlet and outlet arrangements are critical.
Poorly designed inlets and outlets permit excessive short
circuiting. Arrangements that direct flow tangentially are
vastly superior to arrangements that direct flow from inlet
toward outlet structure.
Monitoring Treatment After Rainfall Breaches the
Required Freeboard of a Lagoon
The authority monitoring a lagoon should specify a treatment
rate for the waste water breaching the required freeboard
high enough to restore the required freeboard in a
reasonable time period. If treatment is delayed, or
conducted at an unreasonably slow rate, overflow will occur
from rains considerably below the heaviest expected rainfall
in a 10 or 25 year period.
Control of Unusual Discharges to Pond
Monitoring authorities should require a report on all waste
water streams discharged to the recirculation and reuse
pond. Problems may arise at plants discharging waste water
from processes other than phosphate manufacturing or
fertilizer phosphate production. Ponds should also be
managed and located in a manner that limits ammonia and
organic compound intrusion.
The recirculation and reuse pond will have considerable
capacity to absorb noncontact cooling water that has become
contaminated by leaks and process waste waters from
ancillary phosphate manufacturing operations at most sites;
however, the situation at a point source should be monitored
to make certain that the point source is not utilizing the
pond as a device for evading regulations on waste water
discharges from unrelated manufacturing operations.
Ponds should be managed and located in a manner that limit
ammonia and organic substance intrusion.
65
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Many objectionable metals are kept under control by the
sedimentation processes in the pond and by the terminal lime
treatment process. The presence of ammonia and of some
organic compounds interfere seriously with these treatment
processes. Particular care should be taken around plants
producing ammonia and other nitrogenous fertilizers; drying
towers and other facilities losing ammonia gas to the
atmosphere are particularly troublesome sources of
contamination. Domestic wastes interfere with metal
precipitation processes and with flocculation and
clarification processes.
Rationale for New Pond "Within the Impoundment" Definition
An explanation was requested for the rationale applied for
adopting the "within the impoundment" definition for new
source impoundments, and for all impoundments constructed on
or after the date of this regulation.
Technical information is provided in this section and
Reference L on the use of underdrainage systems for
collection and removal of the waste water that seeps through
the dam. Information is also provided on the use of relief
wells for removal of seepage water from the toe of dams.
One or both of these systems may be essential to prevent
weakening of a dam by saturation with water. A combination
of underdrainage and relief well systems is a practicable
and economically feasible means of collecting seepage water
and returning it to the lagoon. This combination will cost
very little more than the usual lagoon, with the periferal
collection ditch seepage return system in common use. The
underdrainage combination will cost less than the usual
system at sites with high-cost land.
The underdrainage and relief well system can be operated in
a manner that collects no rain runoff from the outer slope
of the dam. This procedure reduces the waste water volume
that must be treated and discharged during periods when
rainfall exceeds evaporation. Inasmuch as this technology
is readily applicable to new lagoons, for all impoundments
or new source impoundments constructed on or after the date
of this regulation, the term "within the impoundment" for
purposes of calculating the volume of process water which
may be discharged shall mean the water surface area within
the impoundment at maximum capacity.
66
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I LIME |
HOPPER
CAR
DUST COLLECTOR
T3Lti
LIME
FEEDER
STEAM
HOT WATER
TANK
_
STORAGE
TO GYPSUM POND
CALCIUM PHOSPHATE
POND
TO RIVER OR
PROCESS UNITS
CONTAMINATED (POND) WATER TREATMENT
FIGURE VII-1
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SECTION VIII
COST, ENERGY AND NON-WATER QUALITY ASPECT
General
The costs - capital and operating - have been estimated for
the two treatment technologies described in Section VII.
These costs are given as August 1971 dollar values. In the
case of the costs indicated for Containment and Cooling Pond
technology, there is additional explanation made on what
they represent and how they might be used. The costs
indicated for the Contaminated (Pond) Water Treatment
technology are based on a specific treatment capacity such
as would be found at a moderate size production unit. The
following paragraphs provide identification of the cost
elements used in this section and indicated on Table VIII-1.
Cost Elements
Investment
This is the capital cost associated with the engineering;
site preparation; construction and installation; and such
other costs required to place the technology in operation.
It does not include production loss or profits loss that may
be encountered from tying the new facilities into the
existing plant operations.
Interest
This cost is based on the assumption that the capital
expenditure was borrowed at a 7.5% annual interest rate.
Depreciation
The nature and service life expected of this type equipment
were the bases for selection of an assumed ten year straight
line depreciation.
Operating and Maintenance Costs
The items included in this cost element are operating
supplies, replacement parts, insurance, taxes, operating
labor and maintenance labor.
Energy.
69
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This item is the power costs to operate the mechanical
equipment. Electrical energy is assumed at the cost of 10
mils per KWH.
Total Annual Costs
An accumulation of the various cost items described above.
Installation and Operation of Technologies
Containment and Cooling Pond
The cost of this technology is difficult to estimate due to
the need of a specific design for each individual plant.
Pond size is a function of many items including the water
temperature (cooling) required for process, the economics of
land availability, provision for rainfall, and geographical
location. The indicated investment cost is that to
establish a 10" high dike around one (1) acre. This cost
also assumes that the dike will be established from earth at
the site and strictly by large earth-moving equipment - no
transportation of earth to the site. Cost of earth moving
has been estimated at $1.50 per cubic yard.
It can be stated that a minimum containment and cooling pond
for a moderate size plant would be 10 - 20 acres.
Construction time is estimated at 80 hours per acre.
There would be no interruption of plant operation during
construction.
Contaminated (Pond) Water Treatment
This is the same technology and costs estimated for Pond
Water Treatment in the phosphate fertilizer section of the
Basic Fertilizer Chemicals Survey.
Time required for engineering, procurement, and construction
is 15 - 18 months.
There would be no interruption of plant operation during
construction.
Start-up and initial operation would require approximately
24 hours of continuous operation to establish stabilized
conditions.
Air Pollution Control
70
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Air pollution control poses a serious problem in the
industry, particularly in the defluorinated phosphate rock
subcategory. The fluoride expelled from the rock on heating
would cause an extremely serious air pollution situation
without the stack scrubbing applied in the industry. The
EPA air pollution control authorities are initiating studies
to determine the status of the air pollution problem, and
the relationship to the water pollution problem.
Information must also be gathered on radon-222 and the
radioactive breakdown solid substances derived from radon-
222. Radon-222 is an inert gas with a very short half life.
Exposure of human beings to these radioactive products must
be held to safe levels. Hopefully, more definite
information will soon be available on how to deal with this
problem. The use of solid wastes, particularly gypsum, for
home construction is inadvisable unless found to be free of
radioactive component hazard.
Solid Wastes
Many solids residues are left as solid wastes.
For those waste materials considered to be non-hazardous
where land disposal is the choice for disposal, practices
similar to proper sanitary landfill technology may be
followed. The principles set forth in the EPA's Land
Disposal of Solid Wastes Guidelines (40 CFR 211) may be used
as guidance for acceptable land disposal techniques.
For those waste materials considered to be hazardous,
disposal may require special precautions. In order to
ensure long-term protection of public health and the
environment, special preparations and pretreatment may be
required prior to disposal. If land disposal is to be
practiced, these sites must not allow movement of pollutants
such as fluoride and radium-226 to either ground or surface
water. Sites should be selected that have natural soil and
geological conditions to prevent such contamination or, if
such conditions do not exist, artificial means (e.g.,
liners) should be provided to ensure long-term protection of
the environment from hazardous materials. Where
appropriate, the location of solid hazardous materials
disposal sites should be permanently recorded in the
appropriate office of the legal jurisdiction in which the
site is located.
71
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SECTION IX
BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE
INTERIM FINAL GUIDELINES AND LIMITATIONS
Introduction
The effluent limitations which must be achieved by July 1,
1977 are based on the degree of effluent reduction
attainable through the application of the best practicable
control technology currently available. For the non-
fertilizer phosphate chemicals manufacturing industry, this
level of technology is based on the best existing
performance by exemplary plants of various sizes, ages and
chemical processes within each of the industry's categories.
In some cases where no truly exemplary plants were surveyed,
this level of technology is based upon state-of-the-art unit
operations commonly employed in the chemical industry.
Best practicable control technologies currently available in
the non-fertilizer phosphate chemicals industry involve both
in-process techniques and end-of-process treatment.
Based upon the information contained in Section III through
VIII of this report, the following determinations were made
on the degree of effluent reduction attainable by
application of the best practicable control technology
currently available in the individual process of the non-
fertilizer phosphate chemical industry. Each process is
presented separately in the following paragraphs.
Specialized Definitions
(a) Except as provided below, the general definitions,
abbreviations and methods of analysis set forth in 40 CFR
U01 shall apply to this subpart.
(b) For all impoundments constructed prior to the date of
this regulation, the term "within the impoundment" when used
for purposes of calculating the volume of process waste
water which may be discharged shall mean the water surface
area within the impoundment at maximum capacity plus the
area of the inside and outside slopes of the impoundment dam
and the surface area between the outside edge of the
impoundment dam and any seepage ditch immediately adjacent
to the dam upon which rain falls and is returned to the
impoundment. For the purpose of such calculations, the
surface area allowances set forth above shall not be more
73
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than 30 percent of the water surface area within the
impoundment dam at maximum capacity.
(c) For all impoundments or new source impoundments
constructed on or after the date of this regulation, the
term "within the impoundment11 for purposes of calculating
the volume of process water which may be discharged shall
mean the water surface area within the impoundment at
maximum capacity.
(d) The term "pond water surface area" when used for the
purpose of calculating the volume of waste water which may
be discharged shall mean the water surface area at normal
operating level of the pond created by the impoundment for
storage of process waste water. This surface shall in no
case be less than one-third of the surface area of the
maximum amount of water which could be contained by the
impoundment. Normal operating level shall be the average
level of the pond during the preceeding calendar month.
(a), above, applies to all three subcategories; (b) , (c) and
(d) apply to the defluorinated phosphate rock and the
defluorinated phosphoric acid subcategories.
Subpart D - Defluorinated Phosphate Rock Subcategory
The provisions of this subpart are applicable to discharges
resulting from the defluorination of phosphate rock by
application of high temperature treatment along with wet
process phosphoric acid, silica and other reagents.
In establishing the limitations set forth in this section,
EPA took into account all information it was able to
collect, develop and solicit with respect to factors (such
as age and size of plant, raw materials, manufacturing
processes, products produced, treatment technology
available, energy reqxiirements and costs) which can affect
the industry subcategorization and effluent levels
established. It is, however, possible that data which would
affect these limitations have not been available and, as a
result, these limitations should be adjusted for certain
plants in this industry. An individual discharger or other
interested person may submit evidence to the Regional
Administrator (or to the State, if the State has the
authority to issue NPDES permits) that factors relating to
the equipment or facilities involved, the process applied,
or other such factors related to such discharger are
fundamentally different from the factors considered in the
establishment of the guidelines. On the basis of such
evidence or other available information, the Regional
74
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Administrator (or the State) will make a written finding
that such factors are or are not fundamentally different for
that facility compared to those specified in the Development
Document. If such fundamentally different factors are found
to exist, the Regional Administrator or the State shall
establish for the discharger effluent limitations in the
NPDES permit either more or less stringent than the
limitations established herein, to the extent dictated by
such fundamentally different factors. Such limitations must
be approved by the Administrator of the Environmental
Protection Agency. The Administrator may approve or
disapprove such limitations, specify other limitations, or
initiate proceedings to revise these regulations.
The following limitations establish the quantity or quality
of pollutants or pollutant properties, which may be
discharged by a point source subject to the provisions of
this subpart after application of the best practicable
control technology currently available.
(a) Subject to the provisions of paragraphs (b) , (c) , and
(d) of this section, there shall be no discharge of process
waste water pollutants into navigable waters.
(b) A process waste water impoundment which is designed,
contructed and operated so as to contain the precipitation
from the 10 year, 2H hour rainfall event as established by
the National Climatic Center, National Oceanic and
Atmospheric Administration, for the area in which such
impoundment is located may discharge that volume of process
waste water which is equivalent to the volume of
precipitation that falls within the impoundment in excess of
that attributable to the 10 year, 2U hour rainfall event,
when such event occurs.
(c) During any calendar month there may be discharged from a
process waste water impoundment either a volume of process
waste water equal to the difference between the
precipitation for that month that falls within the
impoundment and either the evaporation from the pond water
surface area for that month, or a volume of process waste
water equal to the difference between the mean precipitation
for that month that falls within the impoundment and the
mean evaporation from the pond water surface area for that
month as established by the National Climatic Center,
National Oceanic and Atmospheric Administration, for the
area in which such impoundment is located (or as otherwise
determined if no monthly data have been established by the
National Climatic Center), whichever is greater.
75
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(d) Any process waste water discharged pursuant to paragraph
(c) of this section shall comply with each of the following
requirements:
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed_
(Metric units, mg/1)
Total phosphorus 70 35
(as P)
Fluoride 30 15
TSS 50 25
PH Within the range 6.0 to 9.0.
Rationale^for Best Practicable Control Technology
Currently Available
The criteria used for selection of the technology was
information obtained at three of the four total operating
plants in the U.S. Two of the three plants (survey plants A
and B) have the Containment and Cooling Pond Technology in
service and to date have never found it necessary to treat
or discharge water to navigable waters. Survey Plant C
stated plans of installing this technology in the near
future.
The proposed limitations are based on composite (not grab)
sampling and years of historical effluent data. These
limitations represent values which are being achieved by the
better exemplary plants surveyed.
The volume of process waste water that may be discharged is
determined by the rainfall-evaporation circumstances at the
site, and by the definitions and regulations pertaining to
the structure of the recirculation and reuse pond. Process
waste water discharge is not necessary at some sites.
Plants that discharge process waste water normally do this
only in periods of heavy rainfall.
Discharged effluent must be lime treated. This is a
relatively costly operation. Diligent water conservation
and reuse practices have proven to be the most economical
means to handle the waste water problem.
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Subpart E - Defluorinated Phosphoric Acid Subcategory
The provisions of this subpart are applicable to discharges
resulting from the defluorination of phosphoric acid. Wet
process phosphoric acid is dehydrated by application of heat
and other processing aids such as vacuum and air stripping.
The acid is concentrated up to 70-73 percent P2O5 in the
defluorination process.
The technology described as Containment and Cooling Pond is
defined as the best practicable control technology currently
available. This technology confines all process waste
waters to the plant area. Recirculation of these
contaminated process waters to the process together with
good water management practices essentially eliminate the
need for treatment or discharge of treated contaminated
process water to navigable waters. In the event of a need
for emergency type discharge, then the Contaminated (Pond)
Water treatment technology or a facsimile of it would also
be indicated.
The following limitations establish the quantity or
quality of pollutants or pollutant properties, which may be
discharged by a point source subject to the provisions of
this subpart after application of the best practicable
control technology currently available:
(a) Subject to the provisions of paragraphs (b), (c), and
(d) of this section, there shall be no discharge of process
waste water pollutants into navigable waters.
(b) A process waste water impoundment which is designed,
contructed and operated so as to contain the precipitation
from the 10 year, 2U hour rainfall event as established by
the National Climatic Center, National Oceanic and
Atmospheric Administration, for the area in which such
impoundment is located may discharge that volume of process
waste water which is equivalent to the volume of
precipitation that falls within the impoundment in excess of
that attributable to the 10 year, 24 hour rainfall event,
when such event occurs.
(c) During any calendar month there may be discharged from a
process waste water impoundment either a volume of process
waste water equal to the difference between the
precipitation for that month that falls within the
impoundment and either the evaporation from the pond water
surface area for that month, or a volume of process waste
water equal to the difference between the mean precipitation
for that month that falls within the impoundment and the
77
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mean evaporation from the pond water surface area for that
month as established by the National Climatic Center,
National Oceanic and Atmospheric Administration, for the
area in which such impoundment is located (or as otherwise
determined if no monthly data have been established by the
National Climatic Center), whichever is greater.
(d) Any process waste water discharged pursuant to paragraph
(c) of this section shall comply with each of the following
requirements:
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed_
(Metric units, mg/1)
Total phosphorus 70 35
(as P)
Fluoride 30 15
TSS 50 25
pH Within the range 6.0 to 9.0.
Subpart F - Sodium Phosphates Subcategory
The provisions of this subpart are applicable to discharges
resulting from the manufacture of purified sodium phosphates
from wet process phosphoric acid.
The technology described as Contaminated (Pond) Water
Treatment is defined as the best practicable control
technology currently available, and/or in-process technology
- whichever will achieve the same results. Process waste
water is also continuously treated and discharged to
navigable waters. A lagoon recirculation system is in use
for treatment of the process waste water from production of
the raw product acid required for sodium phosphates
manufacture, and can be utilized for disposal of troublesome
waste water streams.
The following limitations establish the quantity or
quality of pollutants or pollutant properties, controlled by
this section, which may be discharged by a point source
subject to the provisions of this subpart after application
of the best practicable control technology currently
available:
78
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Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed
(Metric units, kg/kkg of product)
TSS 0.50 0.25
Total phosphorus 0.80 0.40
(as P)
Fluoride 0.30 0.15
pH Within the range 6.0 to 9.0.
(English units, lb/1000 Ib of product)
TSS 0.50 0.25
Total phosphorus 0.80 0.40
(as P)
Fluoride 0.30 0.15
pH Within the range 6.0 to 9.0.
Rationale for Best Practicable Control Technology
Currently Available
The criteria used for selection of the treatment technology
included a variety of items ranging from consideration of
the process characteristics to the known commercial limits
of capability.
In this process, the conditions are such that contaminated
process water cannot be re-used or treated due to the
product purity specifications and the unit operations
reguired to attain that purity. Therefore, fresh water use
is a process requirement and continuous discharge of process
water is a necessity. Based on this consideration, the
capability of treating the contaminated process water to
achieve significant reduction of contaminants to acceptable
levels has been commercially proven. The recognition that
this end-of-process treatment is sensitive to water quantity
variations with subsequent adverse quality effects indicated
the need to base limitations on production- tonnage rather
than the best possible treatment results and concentrations.
Six different process areas contribute to the contaminated
process water stream and process water effluent quantity is
a function of the number of units in instantaneous
operation.
79
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Another consideration was that the proposed guidelines
coincide with commercial operations for reduction of
parameters within limits that would not initiate the need
for additional treatment facilities. That is, the
guidelines proposed coincide with contaminant levels
attainable at the proposed pH 6.0 to 9.0 treatment range.
This pH range permits direct discharge of clarified
effluent, without neutralization. All waste streams that
bear any of the dehydrated products, metaphosphate through
polyphosphate, can be diverted to the recirculation pond
when flow to the clarifier is sufficient to cause a
discharge violation. These modified phosphates create
problems in the usual clarification process. The treatment
system will require a hydrolytic process that converts
phosphate components to the orthophosphate form if
significant quantities of polyphosphate waste water
components are in the stream undergoing lime precipitation
and clarification. These processes are discussed in Section
VII.
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SECTION X
BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
Interim Final Guidelines and Limitations
The effluent limitations which must be achieved by July 1,
1983, are based on the degree of effluent reduction
attainable through application of the best available
technology economically achievable. This level of
technology was based on the very best control and treatment
technology employed by a specific point source within the
industrial category and on sound, established waste water
management and treatment processes.
Specialized definitions are the same as for the best
practicable control technology currently available.
Subpart D - Defluorinated Phosphate Rock Subcategory
The following limitations establish the quantity or
quality of pollutants or pollutant properties, which may be
discharged by a point source subject to the provisions of
this subpart after application of the best available
technology economically achievable:
(a) Subject to the provisions of paragraphs (b), (c), and
(d) of this section, there shall be no discharge of process
waste water pollutants into navigable waters.
(b) A process waste water impoundment which is designed,
contructed and operated so as to contain the precipitation
from the 25 year, 24 hour rainfall event as established by
the National Climatic Center, National Oceanic and
Atmospheric Administration, for the area in which such
impoundment is located may discharge that volume of process
waste water which is equivalent to the volume of
precipitation that falls within the impoundment in excess of
that attributable to the 25 year, 24 hour rainfall event,
when such event occurs.
(c) During any calendar month there may be discharged from a
process waste water impoundment either a volume of process
waste water equal to the difference between the
precipitation for that month that falls within the
impoundment and either the evaporation from the pond water
surface area for that month, or a volume of process waste
water equal to the difference between the mean precipitation
for that month that falls within the impoundment and the
81
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mean evaporation from the pond water surface area for that
month as established by the National Climatic Center,
National Oceanic and Atmospheric Administration, for the
area in which such impoundment is located (or as otherwise
determined if no monthly data have been established by the
National Climatic Center), whichever is greater.
(d) Any process waste water discharged pursuant to paragraph
(c) of this section shall comply with each of the following
requirements:
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed
(Metric units, mg/1)
Total phosphorus 70 35
(as P)
Fluoride 30 15
TSS 50 25
pH Within the range 6.0 to 9.0.
Rationale for the Best Available Technology Economically
Achievable
The rationale is identical to that for best practicable
control technology currently available, except that a
greater freeboard is required for retention of heavier
rains. The required technology to achieve BATEA has been
established at exemplary plants.
Subpart E - Defluorinated Phosphoric Acid Subcategory
The following limitations establish the quantity or
quality of pollutants or pollutant properties, which may be
discharged by a point source subject to the provisions of
this subpart after application of the best available
technology economically achievable:
(a) Subject to the provisions of paragraphs (b) , (c) , and
(d) of this section, there shall be no discharge of process
waste water pollutants into navigable waters.
(b) A process waste water impoundment which is designed,
contructed and operated so as to contain the precipitation
82
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from the 25 year, 2U hour rainfall event as established by
the National Climatic Center, National Oceanic and
Atmospheric Administration, for the area in which such
impoundment is located may discharge that volume of process
waste water which is equivalent to the volume of
precipitation that falls within the impoundment in excess of
that attributable to the 25 year, 24 hour rainfall event,
when such event occurs.
(c) During any calendar month there may be discharged from a
process waste water impoundment either a volume of process
waste water equal to the difference between the
precipitation for that month that falls within the
impoundment and either the evaporation from the pond water
surface area for that month, or a volume of process waste
water equal to the difference between the mean precipitation
for that month that falls within the impoundment and the
mean evaporation from the pond water surface area for that
month as established by the National Climatic Center,
National Oceanic and Atmospheric Administration, for the
area in which such impoundment is located (or as otherwise
determined if no monthly data have been established by the
National Climatic Center), whichever is greater.
(d) Any process waste water discharged pursuant to paragraph
(c) of this section shall comply with each of the following
requirements:
Effluent Effluent
Characteristic limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed^
(Metric units, mg/1)
Total phosphorus 70 35
(as P)
Fluoride 30 15
TSS 50 25
pH Within the range 6.0 to 9.0.
Subpart F - Sodium Phosphates Subcategory
The best available treatment economically achievable
includes the use of the contaminated water pond and
continuous lime treatment of some waste water streams.
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The best available treatment economically achievable
standards for the sodium phosphates subcategory are set at
70 percent of the discharge levels for suspended solids,
fluoride and phosphate waste water components proposed for
the best practicable control technology currently available.
It is the opinion of the Environmental Protection Agency
staff and its advisors that this reduction can be readily
achieved. Improvements of this order and greater are common
in fertilizer phosphate plants facing the need for improved
water conservation practices to avoid excessive costly lime
treatment. The recirculation lagoon is available to handle
waste streams that present difficult treatment problems.
The following limitations establish the quantity or
quality of pollutants or pollutant properties, controlled by
this section, which may be discharged by a point source
subject to the provisions of this subpart after application
of the best available technology economically achievable:
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed
(Metric units, kg/kkg or lb/1000 Ib of product)
TSS 0.35 0.18
Total phosphorus 0.56 0.28
(as P)
Fluoride 0.21 0.11
PH Within the range 6.0 to 9.0.
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SECTION XI
PROPOSED NEW SOURCE PERFORMANCE STANDARDS
AND PRETREATMENT STANDARDS
Proposed New Source Performance Standards
This level of technology is to be achieved by new sources.
The term "new source" is defined in the Act to mean "any
source, the construction of which is commenced after
publication of proposed regulations prescribing a standard
of performance." New source performance standards are to be
evaluated by adding to the consideration underlying the
identification of best practicable control technology
currently available, a determination of what higher levels
of pollution control are available through the use of
improved production processes and/or treatment techniques.
Thus, in addition to considering the best in-plant and end-
of-process control technology, new source performance
standards are to be based upon an analysis of how the level
of effluent may be reduced by changing the production
process itself. Alternative processes, operating methods or
other alternatives are to be considered. However, the end
result of the analysis identifies effluent standards which
would reflect levels of control achievable through the use
of improved production processes (as well as control
technology), rather than prescribing a particular type of
process or technology which must be employed. A further
determination which was to be made for new source
performance standards is whether a standard permitting no
discharge of pollutants is practicable.
The following factors were to be considered with respect to
production processes which were analyzed in assessing new
source performance standards:
a. The type of process employed and process changes.
b. Operating methods.
c. Batch as opposed to continuous operations.
d. Use of alternative raw materials and mixes of raw
materials.
e. Use of dry rather than wet processes (including
substitution of recoverable solvents for water).
85
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f. Recovery of pollutants as by-products.
Specialized definitions are the same as for best practicable
control technology currently available. All new source
ponds come under new source regulations; surface area for
the purpose of computing rainfall is the area within the
impoundment at maximum capacity.
Subpart D - Defluorinated Phosphate Rock Subcategory
The following standards of performance establish the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged by a new
source subject to the provisions of this subpart:
(a) Subject to the provisions of paragraphs (b) , (c) , and
(d) of this section, there shall be no discharge of process
waste water pollutants into navigable waters.
(b) A process waste water impoundment which is designed,
contructed and operated so as to contain the precipitation
from the 25 year, 24 hour rainfall event as established by
the National Climatic Center, National Oceanic and
Atmospheric Administration, for the area in which such
impoundment is located may discharge that volume of process
waste water which is equivalent to the volume of
precipitation that falls within the impoundment in excess of
that attributable to the 25 year, 24 hour rainfall event,
when such event occurs.
(c) During any calendar month there may be discharged from a
process waste water impoundment either a volume of process
waste water equal to the difference between the
precipitation for that month that falls within the
impoundment and either the evaporation from the pond water
surface area for that month, or a volume of process waste
water equal to the difference between the mean precipitation
for that month that falls within the impoundment and the
mean evaporation from the pond water surface area for that
month as established by the National Climatic Center,
National Oceanic and Atmospheric Administration, for the
area in which such impoundment is located (or as otherwise
determined if no monthly data have been established by the
National Climatic Center), whichever is greater.
(d) Any process waste water discharged pursuant to paragraph
(c) of this section shall comply with each of the following
requirements:
86
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Effluent
Characteristic
Maximum for
any one day
(Metric units, mg/1)
Total phosphorus
(as P)
Fluoride
TSS
PH
70
30
50
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
35
15
25
Within the range 6.0 to 9.0.
Subpart E - Defluorinated Phosphoric Acid Subcategory
The following standards of performance establish the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged by a new
source subject to the provisions of this subpart:
(a) Subject to the provisions of paragraphs (b) , (c) , and
(d) of this section, there shall be no discharge of process
waste water pollutants into navigable waters.
(b) A process waste water impoundment which is designed,
contructed and operated so as to contain the precipitation
from the 25 year, 2U hour rainfall event as established by
the National Climatic Center, National Oceanic and
Atmospheric Administration, for the area in which such
impoundment is located may discharge that volume of process
waste water which is equivalent to the volume of
precipitation that falls within the impoundment in excess of
that attributable to the 25 year, 24 hour rainfall event,
when such event occurs.
(c) During any calendar month there may be discharged from a
process waste water impoundment either a volume of process
waste water equal to the difference between the
precipitation for that month that falls within the
impoundment and either the evaporation from the pond water
surface area for that month, or a volume of process waste
water equal to the difference between the mean precipitation
for that month that falls within the impoundment and the
mean evaporation from the pond water surface area for that
month as established by the National Climatic Center,
National Oceanic and Atmospheric Administration, for the
area in which such impoundment is located (or as otherwise
87
-------
determined if no monthly data have been established by
National Climatic Center), whichever is greater.
the
(d) Any process waste water discharged pursuant to paragraph
(c) of this section shall comply with each of the following
requirements:
Effluent
Characteristic
Maximum for
any one day
(Metric units, mg/1)
Total phosphorus
(as P)
Fluoride
TSS
PH
70
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
35
30 15
50 25
Within the range 6.0 to 9.0,
Subpart F - Sodium Phosphates Subcategory
Performance standards for new sources are the same as for
best available technology economically achievable:
The following standards of performance establish the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged by a new
source subject to the provisions of this subpart:
Pollutant or
Pollutant Property
Maximum for
any one day
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
(Metric units, kg/kkg of product)
TSS
Total phosphorus
(as P)
Fluoride
PH
0.35
0.56
0.18
0.28
0.21 0.11
Within the range 6.0 to 9.0.
(English units, lb/1000 Ib of product)
-------
TSS 0.35 0.18
Total phosphorus 0.56 0.28
(as P)
Fluoride 0.21 0.11
pH Within the range 6.0 to 9.0.
Pretreatment Standards for Existing Sources
Subpart D - Defluorinated Phosphate Rock Subcategory
The pretreatment standard under section 307(b) of the Act
for a source within the defluorinated phosphate rock
subcategory which is a user of a publicly owned treatment
works and a major contributing industry as defined in HO CFR
128 (and which would be an existing point source subject to
section 301 of the Act, if it were to discharge pollutants
to the navigable waters), shall be the standard set forth in
40 CFR, 128, except that, for the purpose of this section,
40 CFR 128.121, 128.122, 128.132 and 128.133 shall not
apply. The following pretreatment standard establishes the
guantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged to a
publicly owned treatment works by a point source subject to
the provisions of this subpart:
The volume of waste water that may be discharged is
established by the interim final guidelines for the best
practicable control technology currently available.
Pollutant or Effluent
Pollutant Property Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall^ not exceed
(Metric units) mq/1 of effluent discharged
BOD5 No limitation
TSS No limitation
pH No limitation
Total phosphorus 70 35
Fluoride 30 15
Subpart E - Defluorinated Phosphoric Acid Subcategory
The pretreatment standard under section 307(b) of the Act
for a source within the defluorinated phosphate rock
subcategory which is a user of a publicly owned treatment
89
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works and a major contributing industry as defined in 40 CFR
128 (and which would be an existing point source subject to
section 301 of the Act, if it were to discharge pollutants
to the navigable waters), shall be the standard set forth in
40 CFR, 128, except that, for the purpose of this section,
40 CFR 128.121, 128.122, 128.132 and 128.133 shall not
apply. The following pretreatment standard establishes the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged to a
publicly owned treatment works by a point source subject to
the provisions of this subpart:
The volume of waste water that may be discharged is
established by the interim final guidelines for the best
practicable control technology currently available.
Pollutant or Effluent
Pollutant Property Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
Shall not exceed
(Metric units) mg/1 of effluent__discharged
BOD5 No limitation
TSS No limitation
pH No limitation
Total phosphorus 70 35
Fluoride 30 15
Subpart F - Sodium Phosphates Subcategory
The pretreatment standard under section 307(b) of the Act
for a source within the defluorinated phosphate rock
subcategory which is a user of a publicly owned treatment
works and a major contributing industry as defined in 40 CFR
128 (and which would be an existing point source subject to
section 301 of the Act, if it were to discharge pollutants
to the navigable waters) , shall be the standard set forth in
40 CFR, 128, except that, for the purpose of this section,
40 CFR 128.121, 128.122, 128.132 and 128.133 shall not
apply. The following pretreatment standard establishes the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged to a
publicly owned treatment works by a point source subject to
the provisions of this subpart:
Pollutant or Effluent
90
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Pollutant Property Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall_not exceed_
(Metric units) kg/kkg of product
BOD5 No limitation
TSS~ No limitation
pH No limitation
Total phosphorus 0.80 0.40
Fluoride 0.30 0.15
(English units) lb/IOOO_lb_of_£roduct
BOD5 No limitation
TSS No limitation
pH No limitation
Total phosphorus 0.80 0.40
Fluoride 0.30 0.15
Pretreatment Standards for New Sources
Subpart D - Defluorinated Phosphate Rock Subcategory
The pretreatment standard under section 307(b) of the Act
for a source within the defluorinated phosphate rock
subcategory which is a user of a publicly owned treatment
works and a major contributing industry as defined in 40 CFR
128 (and which would be an existing point source subject to
section 301 of the Act, if it were to discharge pollutants
to the navigable waters), shall be the standard set forth in
40 CFR, 128, except that, for the purpose of this section,
40 CFR 128.121, 128.122, 128.132 and 128.133 shall not
apply. The following pretreatment standard establishes the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged to a
publicly owned treatment works by a point source subject to
the provisions of this subpart:
The volume of waste water that may be discharged is
established by the interim final guidelines for the best
practicable control technology currently available.
Pollutant or Effluent
Pollutant Property Limitations
Maximum for Average of daily
91
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any one day values for thirty
consecutive days
shall not exceed
(Metric units) mq/1 of effluent discharged
BOD5 No limitation
TSS No limitation
PH No limitation
Total phosphorus 70 35
Fluoride 30 15
Subpart E - Defluorinated Phosphoric Acid Subcategory
The pretreatment standard under section 307(b) of the Act
for a source within the defluorinated phosphate rock
subcategory which is a user of a publicly owned treatment
works and a major contributing industry as defined in 40 CFR
128 (and which would be an existing point source subject to
section 301 of the Act, if it were to discharge pollutants
to the navigable waters) , shall be the standard set forth in
40 CFR, 128, except that, for the purpose of this section,
40 CFR 128.121, 128.122, 128.132 and 128.133 shall not
apply. The following pretreatment standard establishes the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged to a
publicly owned treatment works by a point source subject to
the provisions of this subpart:
The volume of waste water that may be discharged is
established by the interim final guidelines for the best
practicable control technology currently available.
Pollutant or Effluent
Pollutant Property Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed^
(Metric units) mg/1 of effluent discharged
BOD5 No limitation
TSS No limitation
PH No limitation
Total phosphorus 70 35
Fluoride 30 15
Subpart F - Sodium Phosphates Subcategory
92
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Subpart F - Sodium Phosphates Subcategory
The pretreatment standard under section 307(b) of the Act
for a source within the defluorinated phosphate rock
subcategory which is a user of a publicly owned treatment
works and a major contributing industry as defined in 40 CFR
128 (and which would be an existing point source subject to
section 301 of the Act, if it were to discharge pollutants
to the navigable waters), shall be the standard set forth in
40 CFR, 128, except that, for the purpose of this section,
40 CFR 128.121, 128.122, 128.132 and 128.133 shall not
apply. The following pretreatment standard establishes the
quantity or quality of pollutants or pollutant properties,
controlled by this section, which may be discharged to a
publicly owned treatment works by a point source subject to
the provisions of this subpart:
Pollutant or
Pollutant Property
Maximum for
any one day
Effluent
^imitations
Average of daily
values for thirty
consecutive days
shall not exceed
(Metric units)
BOD5
TSS
pH
Total phosphorus
Fluoride
kg/kkq of product
No limitation
No limitation
No limitation
0.80 0.40
0.30 0.15
(English units) Ib/IOOO^lb of product
BOD 5
TSS
PH
Total phosphorus
Fluoride
No limitation
No limitation
No limitation
0.80 0.40
0.30 0.15
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SECTION XII
ACKNOWLEDGMENT
This report was prepared by the Environmental Protection
Agency on the basis of a comprehensive study performed by
Davy Powergas, Inc., under contract no. 68-01-1508, model
#2. Mr. R. W. Heinz, Project Manager, prepared the original
(contractor's) report. Mr. Heinz was assisted in the
preparation of this report, by the following personnel: Mr.
D. W. Ross, Mr. Charles T. Harding, Mr. Gerald T. Fields,
Mr. N. V. Fry, Mr. George Telatnik, Mr. Jack Frost, Mr. E.
Singler, and Mr. H. Honey.
This study was initiated under the supervision and guidance
of Elwood E. Martin. The final phases of the study were
supervised by Chester E. Rhines, with extensive transition
assistance from Mr. Martin.
Overall guidance and excellent assistance was provided by
the author's associates in the Effluent Guidelines Division,
particularly Messrs. Allen Cywin, Director, Ernst P. Hall,
Deputy Director, and Walter J. Hunt, Branch Chief.
The cooperation of manufacturers who offered their plants
for survey and contributed pertinent data is greatfully
appreciated. The operations and the plants visited were the
property of the following companies:
Borden Chemical Company, Plant City, Fla.
Occidental Chemical Co., Houston, Tex.
Olin Corporation, Stamford, Conn.
J. R. Simplot Co., Pocatello, Idaho
Thornton Laboratory, Tampa, Fla.
The members of the working group/steering committee who
participated in the internal EPA review are:
•
Mr. Walter J. Hunt, Chairman, Effluent Guidelines
Division
Mr. Elwood Martin, Effluent Guidelines Division
Dr. Robert Swank , NERC, Corvallis (Athens)
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Mr. Paul Desrosiers, ORM, Headquarters
Mr. James Kamihaci, OPE, Headquarters
Dr. Edmund Lomasney, Region IV
Mr. James Rouse, NFIC, Denver
Dr. Chester E. Rhines, Effluent Guidelines Division
Acknowledgement and appreciation is also given to Ms. Kaye
Starr, Ms. Nancy Zrubek, Ms. Alice Thompson, and Ms.
Ernestine Christian of the Effluent Guidelines Division
secretarial staff and to the secretarial staff of Davy
Poowergas, Inc., for their efforts in the typing of drafts,
necessary revisions, and the final preparation of this and
the contractor's draft document.
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SECTION XIII
REFERENCES
A. Phosphoric Acid, Phosphates and Phosphatic Fertilizers by
William Henry waggaman. University Microfilms, Inc., Ann
Arbor, PP. 233-236, original volume copyright 1927, 1952,
by Reinhold Publishing corporation, Library of Congress
Card Number 52-9791.
B. Defluorination of Phosphate Rock by Clinton A. Hollingsworth,
Lakeland, Florida, assignor to Smith-Douglas Company, Inc.,
Norfolk, Va., United States Patent Office Number 2,995,437,
Patented Aug. 8, 1961.
C. Method of Defluorinating Phosphate Rock in a Fluid
Bed Reactor by Clinton A. Hollingsworth and John H. Snyder,
Lakeland, Fla., assignors to the Borden Company, New York, N.Y.
a corporation of New Jersey, United States Patent Office
Number 3,364,008, Patented January 16, 1968.
D. Method^of Agglomerating Phosphate Material by Clinton A.
Hollingsworth and Jack F. Lewis, Lakeland, Fla., assignors,
by mesne assignments, to The Borden Company, United States
Patent Office, Number 3,189,433, Patented June 15, 1965.
E. Chemical Economics Handbook
Stanford Research Institute, Phosphorus and Compounds,
762.2030 A, 762.2030 B, 762.2030 C, December 1969.
F. Phosphorus and Its Compounds
John R. Van Wager, Interscience Publishers, Inc., New
York (1961) Library of Congress Card No. 58-10100.
G• 1972 Fertilizer Summary Data
Norman L. Hargett, National Fertilizer Development Center,
Tennessee Valley Authority, Muscle Shoals, Alabama.
H• Development Document for Effluent Limitations
Guidelines and New Source Performance Standards for_the
Phosphorus Derived Chemicals Segment of the Phosphate
Manufacturing Point Source Category
United States Enivronmental Protection Agency, EPA
440/1-74/006, January, 1974.
I. Development Document^for Effluent Limitations
Guidelines and New Source Performance Standards for the Basic
Fertilizer Manufacturing Point Source Category, United
States Environmental Protection Agency, EPA 440/1-
74-011-a, March, 1974.
97
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J. Engineering Field Manual for Conservation Practices
U.S. Department of Agriculture, Soil Conservation Service
Section I, 1969 and Section 2, 1971.
K- Earth Manual
U.S. Department of the Interior, Bureau of Reclamation,
First Edition, Denver, Colorado, July, 1940 (a new edition
is being printed).
L. Design of Small Dams
U.S. Department of the Interior, Bureau of Reclamation,
Second Edition, 1973.
M. Those Nasty Phosphatic Clay Ponds, Environmental
Science and Technology, page 312, April, 1974.
N. Reconnaissance Study of Radiochemical Pollution from
Phosphate Rock Mining and Milling, National Field Investi-
gations Center-Denver, Denver, Colorado, Revised May, 1974.
O. Interim Radium-226 Effluent Guidance for Phosphate
Chemicals and Phosphate Fertilizer Manufacturing, Statement
of Considerations - August 5, 1974, Criteria and Standards
Division, Office of Radiation Programs, Environmental
Protection Agency, Washington, D.C. 20460.
P. Black & Veatch, Consulting Engineers, Process Design
Manual for Phosphorus Removal, U.S. Environmental
Protection Agency Program 17010 GNP, Contract 14-12-936
(October 1971).
Q. "Water Quality Criteria 1972," National Academy of Sciences
and National Academy of Engineering for the Environmental
Protection Agency, Washington, D.C. 1972 (U.S. Govt. Printing
Office Stock No. 5501-00520).
98
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SECTION XIV
GLOSSARY
Apatite
A natural calcium phosphate usually containing fluorine
occurring as phosphate rock.
PPG
Davy Powergas
Gyp-pond
This term is widely used at fertilizer phosphate plants to
indicate the pond receiving waste water and acting as a
recirculation, cooling and water reuse pond. Many plants
have ponds with a variety of functions such as receiving the
calcium sulfate residue from acid treatment of rock,
receiving calcium fluoride from first stage of lime
precipitation, receiving calcium phosphate and calcium
fluoride sediment from second stage of lime precipitation,
recirculation of stack washing and tail gas scrubber water
and simultaneously removing heat and sediment, and
deposition of troublesome solids, as arsenic sulfide. Local
authorities will have to determine specific pond uses in
order to establish essential solid waste control and
groundwater pollution control measures.
1,000 kilograms
I
liter
Process Waste Water
The term "process waste water" means any water which, during
manufacturing or processing, comes into direct contact with
or results from the production or use of any raw material,
intermediate product, finished product, by-product, or waste
product.
Ton
All uses of term "ton" imply short ton equal to 2,000
pounds.
99
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METRIC UNITS
CQT.V1SRSICN TABLE
o
o
MULTIPLY (ENGLISH UNITS)
ENGLISH UNIT ABBREVIATION
acre ac
acre - feet ac ft
British Thermal BTU
Unit
British Thermal BTU/lb
Unit/pound
cubic feet/minute cfm
cubic feet/second cfs
cubic feet cu ft
cubic feet cu ft
cubic inches cu in
degree Fahrenheit °F
feet ft
gallon gal
gallon/minute gpm
horsepower hp
inches in
inches of mercury in Eg
pounds Ib
million gallons/day mgd
mile mi
pound/square inch psig
(gauge)
square feet sq ft
square inches sq in
tons (short) ton
yard yd
by
CONVERSION
0.405
1233.5
0.252
0.555
0.028
1.7
0.028
28.32
16.39
0.555 (°F-32)*
0.3048
3.785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.609
(0.06805 psig +1)*
0.0929
6.452
0.907
0.9144
TO OBTAIN (METRIC UNITS)
ABBREVIATION METRIC UNIT
ha
cu m
kg cal
kg cal/kg
cu m/min
cu m/rnin
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
km
atm
sq m
sq cm
kkg
m
hectares
cubic meters
kilogram-calories
kilogr£im calories/
kilogram
cubic neters/minute
cubic neters/minute
cubic neters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
kilowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres
(absolute)
square meters
square centimeters
metric tons
(1000 kilograms)
meters
*Actual conversion, nor a multiplier
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