EPA 440/1-73/011
      Development Document for
Proposed Effluent Limitations Guidelines
and New Source Performance Standards
               for the

      BASIC FERTILIZER

           CHEMICALS
           Segment of the
       Fertilizer Manufacturing
        Point Source Category
  UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

              NOVEMBER 1973

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                           publication Notice

This  is  a  development  document  for  proposed  effluent  limitations
guidelines  and  new source performance standards.   As such/  this report
is subject to changes resulting from comments received during the period
of public comments of the proposed regulations.   This  document  in  its
final  form  will  be  published  at  the  time  the regulations for this
industry are promulgated.

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               DEVELOPMENT DOCUMENT

                       for

    PROPOSED EFFLUENT LIMITATIONS  GUIDELINES

                       and

        NEW  SOURCE PERFORMANCE STANDARDS

                     for the

   BASIC  FERTILIZER CHEMICALS SEGMENT OF THE
             FERTILIZER MANUFACTURING

              POINT SOURCE CATEGORY
                 Russell E. Train
                  Administrator

                 Robert L. Sansom
Assistant Administrator for Air 6  Water Proarams
                   Allen Cywin
     Director,  Effluent Guidelines  Division

                 El wood E. Martin
                 Project Officer
                  November, 1973

          Effluent Guidelines Division
        Office  of Air and Water Programs
      U.S.  Environmental Protection  Agency
            Washington, D. C.   20460
            Environmental Protection Agency
            RoPUon V, Library
            £,;;; ^outti Dearborn Street
            Chicago, DM03B 60604

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                                ABSTRACT

This document presents the findings  of  an  extensive  technical  study
conducted  by  Davy  Powergas Inc. on the  fertilizer industry (contract
number 68-01-1508, Mod. #1).

The study included a detailed  and  extensive  exemplary  plant  survey,
contacts  with  consultants  and  government  officials,  and literature
search.

The industry survey  involved  data  gathering,  sample  collection  and
analysis,  and  personal  visitation  with  responsible  plant operating
personnel to obtain first-hand information on  treatment  technology  in
commercial use and technology in development and pilot plant stages.

The  three  main  outputs from the study were:  industry categorization,
recommendations on effluent  guidelines,  and  definition  of  treatment
technology.   The  fertilizer  industry was divided into five categories
for more meaningful separation and division of waste water treatment and
development of effluent guidelines.  These subcategories are  phosphate,
ammonia, urea, ammonium nitrate and nitric acid products.  The phosphate
subcategory  includes  all  ancillary operations necessary for phosphate
production  (e.g.  sulfuric  acid  and   phosphoric   acid) .    Effluent
guidelines  for best practicable control technology currently available,
best  available  technology  economically  achievable,  and  new  source
performance standards are recommended for each category.

Treatment  technologies  such as either in-process or end-of-process add
on units are available or are in advanced development stages  to  enable
existent  and  future fertilizer plants to meet the recommended effluent
guidelines.
                                    iii

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                                CONTENTS

Section

   I     Conclusions                                          1

  II     Recommendations                                      3

 III     Introduction                                         7

  IV     Industry Categorization                             61

   V     Waste Characterization                              65

  VI     Selection of Pollutant Parameters                   77

 VII     Control and Treatment Technology                    81

VIII     Cost, Energy and Nonwater Quality Aspect           113

  IX     Effluent Reduction Attainable Through the
           Application of the Best Practicable Control      123
           Technology Currently Available — Effluent
           Limitations Guidelines

   X     Effluent Reduction Attainable Through the
           Application of the Best Available Technology     131
           Economically Achievable -- Effluent Limitations
           Guidelines

  XI     New Source Performance Standards                   135

 XII     Acknowledgments                                    139

XIII     Bibliography                                       141

 XIV     Glossary                                           145

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                                FIGURES



1.        Nitrogen Fertilizers Plant Locations                17



2.        Phosphate Fertilizers Plant Locations               21



3.        Sulfuric Acid Plant Single Catalysis                25



4.        Sulfuric Acid Plant Double Catalysis                26



5.        Rock Grinding                                       30



6.        Wet Process Phosphoric Acid H2SOU Acidulation       33



7.        NPK Process Nitric Acid Acidulation                 35



8.        Wet Phosphoric Acid Concentration                   37



9.        Merchant Grade Phosphoric Acid Clarification        39



10.      Normal Superphosphate                               41



11.      Triple superphosphate (Run-of-Pile R.O.P.)           43



12       Granulated Triple Superphosphate                    45



13.      Monoammonium Phosphate Plant                        48



1U.      Diammonium Phosphate Plant                          49



15.      Ammonia Plant                                       51



16.      Urea Plant                                          55



17.      Ammonium Nitrate Plant                              58



18.      Nitric Acid Plant                                   60



19.      Sulfuric Acid Effluent Control                      83



20.      Pond Water Treatment                                87



21.      Gypsum Pond Water Seepage control                   90



22.      DAP Self Contained Process                          92



23.      Wet Process Phosphoric Acid System                  94



24.      Sulfuric Acid Dilution with Pond Water              95



25.      Ammonia/Condensate Stripping                        98



26.      Integrated Ammonia/Condensate Stripper Unit         99






                                     vi

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 V
I
          27.       Ammonia/Condensate Air  Stripping                   101

          28.       Urea  Hydrolysis                                    104

          29.       Urea  Hydrolysis                                    105

          30.       Biological  Treatment                               107

          31.       Ion Exchange                                       109

          32.       Oil/Grease  Removal System                          111

          33.       Ammonium Nitrate Effluent Utilization               112
                                              VI1

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                                 TABLES

1.   Integration of Production in the Fertilizer Industry      15

2.   Water Effluent Treatment Costs Phosphate Subcategory     116

3.   Water Effluent Treatment Costs                           119
    Nitrogen Fertilizer Subcategories

4.   Metric Units Conversion Table                            148

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                               SECTION I

                              CONCLUSIONS


The basic fertilizer chemicals segment of the  fertilizer  manufacturing
category  can  be  grouped  into  five  subcategories  for treatment and
identification of plant effluent waste water: phosphate, ammonia,  urea,
ammonium  nitrate  and  nitric acid.  The phosphate subcategory includes
sulfuric  acid  (sulfur  burning),  phosphoric   acid   (wet   process),
phosphoric  acid  concentration,  phosphoric  acid clarification, normal
superphosphate, triple  superphosphate,  and  ammonium  phosphates.   in
these  subcategories  the  treatment  technology does exist, and in some
cases  is  being  used,  that  would  permit  each  and  every  existing
fertilizer   plant   to  meet  the  proposed  best  practicable  control
technology currently available.

Additional treatment methods, in the form of development projects, pilot
plant studies and plant prototype  units,  along  with  technology  from
other  industries  are  being refined, updated and adapted so that their
use will enable fertilizer plant effluent to conform with  the  proposed
best available technology economically achievable.

Process   modifications  and  plant  waste  water  separation/collection
systems along with existing treatment methods will provide the necessary
technology to enable new fertilizer manufacturing  plants  to  meet  the
proposed new source standards.

The  remainder of the fertilizer industry not covered in this study will
be included in a later study.

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                               SECTION II

                            RECOMMENDATIONS

Phosj)hate_Subcategory

1.  The proposed effluent limitation representing the degree of effluent
    reduction attainable through the application of the best practicable
    control technology currently available to the phosphate  subcategory
    is  no  discharge  of  process  waste  water pollutants to navigable
    waters.  A discharge is allowed under the following conditions.

    a.   A  process  waste  water  impoundment,    which   is   designed,
         constructed  and  operated  so  as to contain the precipitation
         from the 10 year, 24 hour rainfall event as established by  the
         U.S.  National  Weather  Service  for  the  area  in which such
         impoundment  is  located   may   discharge   that   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.

    b.   During any calendar month in which  the  precipitation  exceeds
         the  evaporation  for  the  area in which a process waste  water
         impoundment is located, as established  by  the  U.S.  National
         weather  Service  (or  as  otherwise  determined  if no monthly
         evaporation data have been established by the National  Weather
         Service)  in the area in which a process waste water impoundment
         is located there may be discharged from such impoundment either
         a volume of process waste water equal to the difference between
         the  precipitation  and  the  evaporation  for  that month or a
         volume of process waste water equal to the  difference  between
         the  mean precipitation and the mean evaporation for that  month
         as established by the U. S. National weather  Service  for  the
         preceeding 10 year period, whichever is greater.

    c.   Any process waste water discharged pursuant to  subparagraph(b)
         above shall not exceed each of the following requirements:

    Parameter        Maximum daily       Maximum average of daily values
                     concentration       for periods of discharge covering
                                         10 or more consecutive days
                        mg/1                 mg/1

    phosphorus   (P)      20                  10
    fluoride as (F)       30                  15
    nitrogen as (N)       10                   5
    total suspended
      nonfilterable
      solids             30                  15

         The pH of the water discharged shall be within the range of 6.0
         to 9.0 at all times.

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2.   The proposed effluent limitation representing the degree of effluent
    reduction attainable  by  the  application  of  the  best  available
    technology  economically achievable is no discharge of process waste
    water pollutants to navigable waters.   A discharge is  only  allowed
    under  the  following  condition.  A process waste water impoundment
    which is designed, constructed and operated so  as  to  contain  the
    precipitation   from   the  25  year,   24  hour  rainfall  event  as
    established by the U.S. National Weather Service  for  the  area  in
    which  such  impoundment  is  located,  may discharge that volume of
    precipitation that falls within the impoundment in  excess  of  that-.
    attributable to the 25 year, 24 hour rainfall event, when such even4:
    occurs.

3.   The standard of performance  representing  the  degree  of  effluent
    reduction  obtainable  by  the  application  of  the  best available
    demonstrated control technology, processes,  operating  methods,  or
    other alternatives is no discharge of process waste water pollutants
    to  navigable waters.  The same conditions listed for best available
    technology economically achievable apply.

Ammonia Subcategory

The proposed effluent limitations for the ammonia subcategory are listed
in the table below.  The following abbreviations apply:

BPCTCA - best practicable control technology currently available
BATEA  - best available technology economically achievable
BADCT  - best available demonstrated control technology

                           BPCTCA         BATEA         BADCT
                       nJSQthly.  daily  monthly  daily  fflSBthly  daily
Ammonia  (NH.3) Nitrogen
kg/kkg  (lb/1000)
  of product           0.0625   0.125  0.025    0.05   0.055    0.11

Oil and Grease
kg/kkg  (lb/1000 Ib)
  of product           0.0125   0.025  0.0125   0.025  0.0125   0.025

The above monthly limitations represent the  maximum  average  of  daily
values for any period of 30 consecutive days.  The daily maximum average
is  twice  the  30 day maximum average.  pH shall be within the range of
6.0 to 9.0 at all times.

Urea_Subcategory

The proposed effluent limitations for the urea subcategory are listed in
the following table:

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                           BPCTCA       BATEA       BADCT
                       SPHthly. d§ii¥ SJPJSthiY. daily 212Dthly daily
Ammonia  (NH3)  Nitrogen
kg/kkg (lb/1000 Ib)
  of product
  nonprilled urea      0.0375  0.075  0.015   0.03  0.0325   0.065
  prilled urea         0.05    0.1    0.015   0.03  0.0325   0.065

Organic Nitrogen
kg/kkg (lb/1000 Ib)
  of product
  nonprilled urea      0.0625  0.125  0.025   0.05  0.0375   0.075
  prilled urea         0.125   0.25   0.0375  0.075 0.0625   0.125

The above monthly limitations represent the  maximum  average  of  daily
values for any period of 30 consecutive days.  The daily maximum average
is  twice  the  30 day maximum average.  pH shall be within  the range of
6.0 to 9.0 at all times.

Ammoniurn_Nitrate Subcategory

The proposed effluent limitations for the ammonium  nitrate  subcategory
are listed in the following table.

                           BPCTCA         BATEA         BADCT
                       monthly   daily  monthly daily  2}22£l}iY   dai.ly
Ammonia  (NH3)  Nitrogen
kg/kkg (lb/"?000 Ib)
  of product           0.05      0.1    0.0075  0.015  0.05     0.1

Nitrate  (NO3)  Nitrogen
kg/kkg (Ib/ToOO Ib)
  of product           0.0625    0.125  0.0125  0.025  0.025   0.05

The  above  monthly  limitations  represent the maximum average of daily
values for any period of 30 consecutive days.  The daily maximum average
average is twice the 30 day maximum average.  pH  shall  be  within  the
range of 6.0 to 9.0 at all times.

Nitric_Acid_ Subcategory

The  proposed  effluent  limitation  representing the degree of effluent
reduction attainable by the application of the best practicable  control
technology  currently  available, best available technology  economically
achievable,  and  best  available   demonstrated   control   technology,
processes,  operating  methods, or other alternatives is no  discharge of
process waste water pollutants to navigable waters.

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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 Administrator pursuant to Section 304 (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 practicable control
technology currently available and  the  degree  of  effluent  reduction
attainable  through  the  application  of  the best control measures and
practices  achievable  including  treatment  techniques,  processes  and
procedure  innovations,  operation  methods and other alternatives.  The
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 within the fertilizer manufacturing category
of point sources, which included within the list published  January  16,
1973.

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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 separate 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 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  constitutents  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 in-plar.t an>l.
end-of-process technologies, whicn are  existent  or  oapabl-  of  he:r.•*
designed  for  each  segment.  It also included an identification of, in
terms of the amount of constituents  (iricludino thermal)  and the effluent
level resulting from the  application  of  each  of  the  treatment  -.nd
control technologies.  The problems, limitations and reliability of each
was  also  identified.   In  addition,  the  nonwater  impact  of  these
technologies upon other pollution problems, including air, solid  waste,
noise  and  radiation  were also identified.  The eneray requirements of
each control and treatment technology was  identified as well as th^- 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  technology
economically  achievable,"  and the  "best  available demonstrated control
technology, processes, operating methods,  cr  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.

Delineat ion ^ of^Study

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The   effluent  limitations  guidelines  and  standards  of  performance
proposed in this report were developed from operating data, sampling and
information gathered from some twenty-five (25)  plants.  The methods and
procedures used in the  accumulation  of  that  overall  information  is
described in the following paragraphs.

Initial  consideration was directed to identification and categorization
of the various processes defined as comprising the fertilizer industry.

These processes and the corresponding Standard Industrial Classification
codes are defined as:
Chemical

Sulfuric Acid
     Sulfur burning only.

Phosphoric Acid
Including phosphate rock grinding when it is performed
on the immediate vicinity of the acid production unit.

Phosphoric Acid concentration

Phosphoric Acid Clarification

Normal Superphosphate

Triple Superphosphate
Both run-of-pile and granulated processes

Ammonium Phosphates

Ammonia

Urea

Ammonium Nitrate
  SIC


 2819,  2871



 2819,  2817

 2819,  2817

 2819,  2871

 2871

 2871


 2871

2819

2818

2819
The objective was to categorize the many processes into the least number
of units that are practical  for  the  end  purpose  of  water  effluent
monitoring  and structuring of specific fertilizer complexes for EPA and
State  enforcement  officials.    Categorization   inherently   included
determination of those point sources which required separate limitations
and standards.  The overall concept was to provide sufficient definition
and  information on an unitized basis to allow application of a building
block principle.   Such  classification  of  data  readily  permits  the
structuring  of  total  water  effluent  information  for  any  specific
fertilizer  complex  regardless  of  the   multiplicity   of   processes
comprising its make-up.
 §§§s_for_Definiti Qn_cf-Technology^Levels_

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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, information from  qualified consultants, and
cross  reference  with  related   but   more   commonly   non-fertilizer
technologies utilized in other industries.

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.
Criteria  developed  for this purpose of plant evaluation and subsequent
sampling consideration are listed below.

    1)   Discharge Effluent Quantities

    Installations with low effluent quantities and/or  the  ultimate  of
    "no discharge".

    2)   Effluent_Contaminant Level

    Installations  with  low  effluent  contaminant  concentrations  and
    quantities.

    3)   Effluent_Treatment_MethgdandT Effectiveness

    Use  of  best  currently  available  treatment  methods,   operating
    control, and operational reliability.

    1)   Water Managernent^Practice

    Utilization of good management practices such as main water  re-use,
    planning   for   seasonal   rainfall   variations,   in-plant  water
    segregation and proximity of cooling towers to operating units where
    airborne contamination can occur.

    5    Land Utilization
                                     10

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    Consideration of land area involved in water effluent control system
    with the most acceptable being those with the least area.

    6)    Air_Polluticn_Control

    Those plants with the most comprehensive and effective air pollution
    control.  In turn liquid effluent from such plants may represent the
    most serious water effluent condition.

    7)    Geograghi c Location

    Those facilities in close proximity to  sensitive  vegetation,  high
    population  density,  land  availability,  and  areas where local or
    state standards are mcst restrictive.

    8)    Management Operating Philosophy

    Plants whose management insists upon effective equipment maintenance
    and housekeeping practices.

    9)    Raw Materia1s

    Installations utilizing  different  raw  materials  where   effluent
    contaminants differ in impurity type or concentration.

    TO)  Diversity of Processes

    On the basis that other criteria are  met,  then  consideration  was
    given   to   installations   having  a  multiplicity  of  fertilizer
    processes.

    11)  Production

    On the basis that other criteria are equal, then  consideration  was
    given  to  the  degree of above design production rate realized from
    equipment that is water pollution sensitive.

Each of the above criteria were, in turn, assigned a range of  numerical
grade  values to allow an overall numerical evaluation of each plant and
the selection of exemplary plants in each category.

A tentative exemplary plant list was compiled.   The  initial  list  was
composed  chiefly  from  the input of three organizations (Section XII -
ref. 30, 38, 39) .  These organizations had data  and  plant  information
obtained from permit application, in-hcuse knowledge of the nitrogen and
phosphate fertilizer industries which together with information obtained
through  private  conversations  with  knowledgeable  industry personnel
completed  the  list.   This  list  was  then  presented  to  the  trade
organization for comments and suggestions.

Contact  was then made with the plants on the list.  Initial contact was
made by the EPA Project Officer to the corporate official  suggested  by
the  trade organization.  This was followed with a second contact by the
                                     11

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contractor  to  the  specified  plant  manager  with  the  objective  of
scheduling  a  plant  screening  visit.   The  screening visit served to
acquaint the plant manager with the purpose and intent of the  study  as
well  as  the  opportunity  to  consider  whether or not there should be
participation.  Participation in  the  study  was  kept  on  a  strictly
voluntary  basis.   It  is  well  to clarify that every plant contacted,
willingly cooperated and that industry cooperation was outstanding.

The screening visit also served as either a confirmation of the  initial
tentative   listing   of   a   plant  in  an  exemplary  category  or  a
reconsideration of that rating.  Such an evaluation  was  made  after  a
discussion   on   data   availability,  review  of  the  facilities  for
segregation and flow ironitoring of individual  processes,  and  a  plant
inspection  trip.   A  variety  of  situations  were encountered.  These
ranged  from  decisions  not  to  include  a  specific  plant,  althouah
exemplary,  to  learning  of  another  facility  which  more  completely
fulfilled the study objectives.  Some  plants  had  complete  individual
process  effluent  records  together  with  sample validation from other
private or state agencies.  It was found that the majority of the plants
monitor only the main complex effluent streams and  have  little  or  no
knowledge  of individual process effluents.  Consequently, the screening
visits prompted decisions to both delete and add to the list  of  plants
exhibiting exemplary water effluent conditions.

Sample_CQllection 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.  Six persons
were used.  The fertilizer  plant  operating  experience  of  these  six
people  ranged  from  a minimum of 14 years to 24 years with the average
being 20 plus 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.
                                     12

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 3)    Evaluation   of   the   effect   if   any   of    seasonal    rainfall,
 particularly  on  ncn-point  effluent and ponds.

 U)    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,  cr  continuous  types;   shift,   daily  or weekly
 frequency,  etc.   All samples   collected   by   the contractor were
 composite samples composed of  a   minimum   of  four with   the  vast
 majority  containing eight  or more grab samples all  caught at regular
 time intervals  throughout the sample  period.  Sample periods except
'for  special conditions were a minimum  of four  (4) hours.

 6)    Validation  of data via intimate knowledge 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  commerical laboratory,  was  conducted on  each plant
 visited.   A   total of 25  plants  were  inspected.  Of these  10 plants
 were selected,   based  upon the   6 criteria  for  verification   of
 effluent  limits  data.
                                13

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GENERAL_DESCRIPTIQEL QF THE INDUSTRY

The  U.S.  fertilizer industry has undergone such significant changes in
the past  thirty  years  that  it  has  lost  its  old  stigma  of  "mud
chemistry".   The  sledge  hammer  and shovel days have been replaced by
large, modern, fume  free,  plants  operated  from  an  air  conditioned
control room.

Eighty  percent  of  the volume of agricultural chemicals used today are
materials that were not available in their present form at the  time  of
World  War  II.   Fertilizer  use today, in terms of plant nutrients, is
four and one quarter  times  as  great  as  it  was  in  1940.   On  the
assumption  that  this fertilizer is properly used, it represents one of
the major reasons why farm yields are up and unit costs are  lower.   It
has  been estimated that the use of commercial fertilizer saves the U.S.
public $13 billion a year on food bills or about $70 a year per  person.
Large  scale  centrifugal  compressor  ammonia plants, increasing single
train plant capacities from 90-180  to  1400-1800  kkg/day   (100-200  to
1500-2000 tons/day); sulfuric acid plant capacity increased from 270-450
to 1800 kkg/day  (300-500 to 2000 tons/ day); and development of ammonium
phosphate   granule  fertilizers:  illustrate  the  dramatic  technology
change.

This study considers the production of two of the three basic fertilizer
ingredients -  nitrogen   (N)   and  phosphate   (P2O5) ,  the  third  being
potassium  oxide (K20) .  The following tabulation indicates the past and
predicted  North  American  consumption  growth  of   the   former   two
ingredients.


                        Year            '65-70  '70-80
                                        Growth  Growth  '65-80
                      170  195  1980  Rate_  _Rate   Increase
    N            4.5   7.2  11.6  16.9   1056     9*      275X
    P205         3.6   5.0   6.3   8.0    7%     5%      122%

Figures Represent Millions Of Metric Tons


It  can  be  noted  that  N consumption is expected to show the greatest
future growth rates as well as the largest increase in absolute tonnage.
Somewhat coincidentally the N and P.2O5  type  of  ingredient  separation
also  applies  to  production  facilities.   That  is,  various  N  type
fertilizer materials are usually produced in a plant complex  which  has
only  N  type  process  units.   Similarly, various phosphate fertilizer
materials are usually produced in a plant complex which  has  only  P1O5
type  process  units.  This  is demonstrated by Table 1.  As a result of
this natural separation,  each  of  the  two  types  will  be  discussed
separately throughout this report.

Fertilizer  industry  jargon identifies  two types of product - nonmixed
and mixed.  straight fertilizers are defined as those which contain only

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                                                  Table  1
No. of
Companies
22
2
2

3
3
1
3
6
1
7
3
1
1
3
1
2
13
5
3
1
16
1
2
1
4
1
1
1
2
1
2
2
1
1
1
3
7
1
1
1
1
;
160
Intergration of Production in the Fertilizer Industry
No. of
NH3 U N.A. A.N. S.A. Wet A. P. TSP SPA Plants
X 22
X 2
X 2
XX 12
XXX 9
I/ X 3
X 1
I/ X X 6
X 6
XX X j
I/ X X 14
I/ X X X 9
X I/ X X X 4
I/ X X X X 4
X 6
XX 3
XX 4
XX 26
XXX 15
XXX 9
XXX 3
X X X X 64
XX X 3
XXX X 8
XXX X 4
X X X X X >()
x x x x i/ xx x "7
XXX 4
X X X X 3
x x /,
X
XXX 6
X XXX 8
XX XXX ',
X X X X 4
x X X X X 5
X X XXX J 5
X 14
XXX 4
X X X X X 6
X X X X A
X X X X X 5
XXXXXXX 7
390
_!/ Not identified individually in data used to develop this list, but must assume existence
   of sulphuric acid facility as intermediate to wet acid production.
2l Only 109 firms—includes more than one location of plant operations for some firms.
U     Urea
N.A.  Nitric acid
A.N.  Ammonium nitrate
S.A.  Sulfuric acid
Wet   Wet phosphoric acid
A.P.  Ammonium phosphate
TSP   Triple Superphosphate
SPA   Superphosphate acid

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a single major plant nutrient.   Mixed fertilizers are defined  as  those
which  contain  two  cr more primary plant nutrients.  Mixed fertilizers
can  be  produced  by  chemically  reacting  different  ingredients  and
utilizing  the  chemical  reaction  as  the  binding force; or simply by
mechanically blending  together  straight  fertilizers.   The  following
tabulation  lists  the principal straight and mixed fertilizers produced
in the U.S.

     Straight_Fertilizers __             Mixed_Fertilizers

     Nitrogen Fertilizers

              Ammonia
              Urea
              Ammonium Nitrate

     Phosphate _Ferti lizers

              Phosphoric Acid             Ammonium Phosphates
              Normal Superphosphate
              Triple Superphosphate
Nitrogen based fertilizers have in the past realized both  the  greatest
consumption  and  industry  growth  rates  of the three basic fertilizer
nutrients  (N, P2O5 and K2O) and are predicted to continue to do  so  for
the near future.  A possible reason for this may be due to the fact that
application   of   N-based   fertilizers  can  create  spectacular  crop
responses.  Such response however is comparatively short lived  and  can
result  in  disastrous  crop  failures  unless  the  N  fertilization is
followed with V2O5 and K.2O fertilization within one or two years.   This
lead  time  and/or the realization of the need for F2o5_ and K2_O addition
is certainly contributary to the lag time between N and P2O5_ - K2_O usage
and production.

The compounds used and means of  applying  nitrogen  to  the  soil  have
undergone  radical  changes since the early nineteen hundreds.  Prior to
this time practically all fertilizer nitrogen came from natural  organic
materials.   Then  between  1900  and  1920  the  combination of natural
nitrates and  by-product  ammonia  from  ccke  oven  gas,  supplied  th»
majority  of  the nitrogen used by the fertilizer industry.  This period
concluded with the development of the  Haber-Bosch  process  which  made
possible   the   conversion   of   atmospheric  nitrogen  into  ammonia.
Refinement of this process and development of single pieces of reliable,
large scale  mechanical  equipment  has  been  responsible  for  ammonia
becoming the principal fertilizer material.

Today  in the U.S., there are 171 ammonia plants located in 25 different
states  producing  in  excess   of   17,000,000   kkg/year    (18,700,000
tons/year) .   These plants have annual capacities ranging from 10,000 to
435,000 kkg/year  (11,000 to 480,000 tons/year).  Locations  of  nitrogen
fertilizer  plants  are  indicated on Figure 1.  Ammonia plant locations
                                     16

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   -	^.,,    ,..   ,
r  / . ---—'-   '5^'\'i   '"
                                                  17

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are  selected on the basis of  raw  material  supply  and  proximity  to
market area with the former being the dominating consideration.

Since  atmospheric  nitrogen  can  be  obtained at any location, the raw
material of importance is  hydrogen.   Hydrogen  feedstock  sources  for
modern  ammonia plants are natural gas and petroleum fractions.  In turn
this has selectively placed the  highest  industrial  concentrations  of
ammonia   plants  near  sources  of  these  two  raw  materials,  namely
Louisiana, Texas,  California,  Iowa,  Mississippi  and  Arkansas.   The
midwest  agricultural  section  is the major sales market area with Iowa
being the largest consumer state.

Ammonia plants are classified into two categories - those operating with
reciprocating gas compressors and those operating with  centrifugal  gas
compressors.   Generally speaking, those single train plants with annual
capacities  of  less  than  150,000  kkg/year  (165,000  tons/year)  are
operated  with  reciprocating  compressors  while all larger plants, re-
presenting the more mcdern type, operate with  centrifugal  compressors.
The  breakpoint between the two is strictly economic.  That is, in order
to realize low per ton production costs industry has been building  ever
larger  single  train plant capacities.  Introduction of the centrifugal
unit in  this  process  permitted  dramatically  increased  single  unit
compressor  capacity which is directly reflected in lower capital costs.
To appreciate the effect  of  the  centrifugal  compressors  on  ammonia
processing  requires  only a review of what has occurred since 1955.  In
1955  single  train  capacities  of  270  kkg/day   (300  tons/day)  were
considered  large plants.  Today, 900 kkg/day  (1000 tons/day)  plants are
commcr., several 1360 kkg/day  (1500 tons/day) units are in operation  and
plans  are  being  made  to  build  2300 kkg/day  (2500 tons/day) plants.
These larger units have not been without problems in regard to on-stream
time but it is unlikely that future U.S. plants will be  less  than  900
kkg/day  (1000 tons/day) capacity.

As  previously  mentioned, it is modern practice to use an ammonia plant
as a basic unit and then  integrate  it  with  other  process  units  to
manufacture  a  range  cf different products.  An important process unit
usually associated with  an  ammonia  plant  in  a  nitrogen  fertilizer
complex  is  nitric  acid.  There are approximately 124 operating nitric
acid plants in the U.S. with capacities ranging from  7,000  to  240,000
kkg/year  (8,000 to 265,000 tons/year).  Output from these plants is used
as an intermediate feed stock for the production of ammonium nitrate.

Ammonium  nitrate ranks second only to ammonia as a source of fertilizer
nitrogen.  Production of this material for  fertilizer purposes increased
very rapidly in the period 1950-1965 to the point that it  provided  32%
of the total fertilizer N market.  Since 1965, use of this fertilizer in
terms  of  market  percentage  has  been  decreasing.   This decrease is
expected to continue at a slow rate for  the   foreseeable  future.   The
reason  for  this  decline  is  the increased  usage of higher N analysis
materials such as ammonia and urea,  82%  and  46%  N  respectively,  as
compared to the  34% N in ammonium nitrate.
                                     Ib

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Currently there are 83 plants
in   capacity   from  9,000
tons/year).   Approximately 50
used  as  fertilizer  and the
use.  The majority are small ,
Use of urea (46%N)  as a source'
development which was prcmpte
2%  of  the  U.S. fertilizer
has increased at an annual 1
total  in  1971,  a  four  fo
expected that this growth rate;
                              located (see Figure 1)  in the U.S. ranging
                             to  295,000  kkg/year  (10,000  to  325,000
                               of the production from  these  plants  is
                              balance as explosives and other industrial
                              nd have been in service for many years.

                               of fertilizer N has been a fairly  recent
                               by shipping costs.  In 1957 approximately
                             r^itrogen was supplied by urea.  Consumption
                               a year rate to approximately 12%  of  the
                              d  increase  in  the past 10 years.  It is
                               will continue.
                         plant, s
There are 59 operational
capacity  from  7,000  to 350,
Approximately 75% of the tota
the  balance  used  fcr  catt
contains the highest percent l
fact  that  there are nc stor
that urea will continue to be

Phosphate_Fertilizer Industry
The phosphate fertilizer indu
developments  that  the  nitrogen
years there have been dramati
and industry image.
           1955 phosphate was
           The majority of phc
production costs and simplicil
being produced in a myriad of
steadily  decreased  and  has
phosphate materials necessitai
efficiencies.  In short,  art
control methods.  In crder  t<
acid,  triple  superphosphate
first necessary to modernize
                                (see Figure 1)  in the U.S.   ranging  in
                              000 kkg/year (8,000 to 385,000 tons/year).
                               production is  used as fertilizer  N  with
                              e feed and urea-formaldehyde resins.  Urea
                              ! of any solid fertilizer.  This, plus  the
                              ge and handling explosion hazards, ensures
                              a popular fertilizer material.
                              try has not had the spectacular  technical
                               en industry has shown, but in the past 20
                               changes in production  facilities,  costs
                              considered to be the major U.S. fertilizer
                              sphate nutrient was in the form of  normal
Prior  to
nutrient.
superphosphate  which has a nominal P2O5 percentage of 19- 20%.  The low
                              y of this process resulted in the material
                              small plants throughout the  market  area.
Since  1955  normal  superphosphate1s  share of the phosphate market has
                               been  replaced  with  more   concentrated
                              ing utilization of special unit operations
equipment  and  instrumentation  designed to optimize system control and
                               and  mud  chemistry  was  displaced  with
scientific  methods, definition of process variables, and development of
                                manufacture  merchant  grade  phosphoric
                              and ammonium phosphate in quantity, it was
                              nd  increase  capacity  of  the  essential
intermediate  -  phosphoric  acid.   Phosphoric acid manufacture in turn
required larger quantities  of  sulfuric  acid  (approx.  2.8  kkg  100%
sulfuric  acid  for  each kkg of P2O5 as phosphoric acid).   In the early
1960's, 550 kkg/day  (600 tons/day) sulfuric acid plants were  considered
large.   By  1965, single train sulfuric acid plants of 900-1100 kkg/day
(1000-1200 tons/day)  capacity became  common  with  additional  capacity
increases   to  1400  -  1800  kkg/day   (1600-2000  tons/day)   by  1967.
Similarly, large wet process phosphoric acid plants in the early  1960's
were  180-270 kkg/day (200-300 tons/day) P2O5 units with multiple pieces
of  equipment  required  to  perform  single  unit  operations  such  as
acidulation and filtration.  By 1965, single train phosphoric acid units
                                     19

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and single unit operations equipment with capacities of 450 kkg/day (500
tons/day)   P2O5  became  commonplace  followed  with an 800 kkg/day (900
tons/day)  unit by 1967.  several plants in the design stages  will  have
capacities of 900-1100 kkg/day (1000-1200 tons/day).

As  a  result normal superphosphate's share of the fertilizer market has
been steadily decreasing.  It is expected  that  normal  superphosphates
share  of  the  phosphate market will finally stabilize at approximately
18%.  This steady market loss caused several of the  smaller  plants  to
shut  down.   Today  there  are approximately 214 plants with capacities
ranging from (15,000 to 300,000 tons/year) still  in  operation.   These
plants  are  located  over  a wide cross-section of the market area (See
Figure 2).   In  contrast  to  the  ether  phosphate  processes,  normal
superphosphate  plants  are  usually not integrated with phosphoric acid
complexes but are most generally connected with fertilizer mix plants.

Essentially all the ether phosphatic fertilizer process units  are  like
the  nitrogen  fertilizer  industry  and  are  integrated into phosphate
complexes.  The majority of these large complexes are located  near  the
phosphate  rock  source  in  Florida.   There  are a few fairly isolated
complexes located along the Mississippi Piver,  North  Carolina,  Idaho,
Utah  and  California.   The  North  Carolina  and Western units  (except
California) utilize locally mined rather than  Florida  mined  phosphate
rock.

Generally  wet  process  phosphoric  acid  is  used  as an intermediate.
Steadily increasing quantities of merchant grade acid are annually being
sold but such acid is in turn used either in fertilizer mixing plants or
ir. preparing liquid fertilizer solutions.  Merchant grade  acid   is  low
strength   (30% P2O_5) acid which has been concentrated to 52-54* P2_O5 and
then processed to remcve a sufficient quantity of  solid  impurities  to
enable  it  to  be  shipped  and  distributed  without  difficulty.   An
additional near  future  market  for  merchant  grade  acid  is   in  th<=
production  of  high  quality  technical  grade acid.  This is presently
dominated by phosphoric acid produced via the electric  furnace   process
 (see the phosphate manufacturing, development document).  To date, there
are  no  facilities  producing  technical grade acid from merchant grade
acid in the U.S., but serious  consideration  is  being  given  to  such
projects.   One  procedure for producing  such a quality acid is to treat
merchant grade, wet process phosphoric acid via  solvent  extraction  to
remove impurities.

A limited number of phosphoric acid plants also produce fluosilicic acid
 (15-25%  H2_SiF6) as a by-product of the  phosphoric acid concentration or
sulfuric acid digestion steps.  The equipment required for this   product
is   essentially  "add  on"  equipment  which does not  affect the  overall
process.   Such production significantly   reduces  the  total  amount  of
fluorine in the raw waste load.

Currently  there  are  39 wet process phosphoric acid plants operating in
15  states with  capacities  ranging  from  41,000  to  360,000  kkg/year
 (45,000  to  400,000 tons/year) F2O5  (See Figure 2).   Five sizeable,  new
plants are currently in design  and  construction   stages  and  will  be
                                     20

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  FIGURE   2
     MAP/DAP
AMMONIUM PHOSPHATE
  PLANT LOCATIONS
21

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brought  on stream in 1974 and 1975.   These new units will primarily add
to existing plant capacities and will include only one new manufacturer.

Triple superphosphate (46-48%  P2O5),  a  concentrated  fertilizer,  has
partially  displaced normal superphosphate.  This material has enjoyed a
very rapid market growth since 1950 to the point where it is the  second
largest  quantity of fertilizer phosphate produced.  There are two types
of  triple  superphosphate   (TSP)   produced.   One  is   a   non-uniform
pulverized  material designated as run- of-pile (ROP) TSP.  The other is
a hard, uniform pelletized material designated as granular TSP or  GTSP.
ROP  is  the older process and from an overall standpoint is a difficult
process to environmentally control.   In  addition,  the  product  is  a
troublesome  material  to  store, handle, and ship.  Consequently within
the TSP family, ROP production is at best remaining  constant  and  GTSP
production  is  constantly  increasing.   There are several plants which
process ROP into a granular material  but  this  imposes  an  additional
process  step  and  cost.   Practically  all  new future facilities will
utilize the GTSP process.

TSP production units are always located within a phosphate  complex  due
to  their dependency on phosphoric acid supply.  There are approximately
20 ROP production units ranging  in  capacity  from  32,000  to  440,000
kkg/year   (35,000  to  600,000  tons/year).  Currently, there are 5 GTSP
plants in operation and 3 new plants in design and construction  stages.
The  majority  of  the  GTSP  process  units are located within the same
complexes as the ROP units.

Ammonium phosphates are  the  concentrated,  mixed  fertilizer  products
which  in  the  past  20  years  have  been  the growth phenomena of the
phosphate industry.  This category includes both monoammonium  (MAP)  and
diammcnium   (DAP)  phosphate grades.  The only difference between grades
is the degree of ammoniation.  Annual compound rate of growth  over  the
past  ten  years  has been 19.8%.  Such popularity is due to a number of
factors which are are so prominent that ammonium phosphates are  certain
to  continue  as  a  most  important mixed fertilizer material.  DAP has
emerged and will continue to be the dominant grade.  Both  products  are
made  by  neutralizing  30-40%  P2.°5  phosphoric  acid  with  the proper
quantity of ammonia.

As with most production processes, plant capacities are constantly being
increased to effect capital cost and production economies.   Commonplace
capacities  prior  to 1973 have been 32-45 kkg/hr  (35-50 tons/hour), but
new plants scheduled for completion  in  1974  will  have  instantaneous
single  train  capacities of up to 90 kkg/hr  (100 tons/hour).  Currently
there are  53 operating ammonium phosphate plants  located  in  the  U.S.
ranging  in  capacity  between  9,000  and  550,000  kkg/year  (10,000 and
600,000 tons/year)  (See Figure 2).
                                     22

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                     SPECIFIC PROCESS DESCRIPTIONS

Phosghate Pertilizer_Industry

The  phosphate  fertilizer  industry  is  defined  as   eight   separate
processes:    sulfuric   acid,  phosphate  rock  grinding,  wet  process
phosphoric  acid,  phosphoric  acid   concentration,   phosphoric   acid
clarification,   normal   superphosphate,   triple  superphosphate,  and
ammonium phosphates.

The two important basic units are sulfuric and  wet  process  phosphoric
acid.   The sulfuric acid unit is essential to the phosphoric acid plant
not only for the basic sulfuric acid raw material but  also  to  produce
steam  for operation of vacuum and evaporation equipment.  Sulfuric acid
is also a basic  raw  material  for  normal  superphosphate  production.
Phosphoric acid is the fcasic raw material for all the other processes.

Essentially  all  existing  phosphate fertilizer complexes are separated
either by geographic location or by area  within  a  general  fertilizer
plant  from  the  nitrogen fertilizer operations.  Such separation was a
significant factor in establishing the separate fertilizer categories.

Since  phosphate  fertilizer  processes  have  either   sulfuric   acid,
phosphate  rock,  or  phosphoric  acid in common, the effluents from the
separate processes also have common  contaminants  which  vary  only  in
concentration.   Primary  contaminants in the effluents from these units
are fluorine  (F) and phosphorus (P).  The only contaminant not common to
all units is nitrogen  (N).  Ammonia is  a  basic  raw  material  to  the
ammonium  phosphate  process  and is the only source of N injection to a
phosphate process effluent. Therefore, with the exception of N, a common
effluent treatment system can be  established  to  treat  the  F  and  P
contaminants   from  all  phosphate  fertilizer  processes.   In  actual
practice, practically all complexes combine the various  unit  effluents
into  a  large  recycle  water  system.  This large contaminated recycle
water system is self contained for a large portion of the year.   It  is
only  when  the  quantity  of recycle water increases beyond capacity to
contain it, that effluent treatment is necessary.  Increases in  recycle
water  inventory  is  usually  due  to an imbalance between rainfall and
evaporation.  In Florida this means that some plants  discharge  treated
effluent up to four mcnths per year.
                                     23

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                  gulfuric Acid_- Process Description
General
In  the  United  States,  essentially  all sulfuric acid utilized in the
manufacture of fertilizer products and intermediates is produced by  the
contact  process.   The process is so named due to the use of a catalyst
surface to speed the oxidation reaction between sulfur dioxide  (SO2)  and
oxygen (O2) .  This reaction  occurs  when  the  two  gaseous  components
"contact"  each  other  on  the surface of pelletized vanadium pentoxide
catalyst to form resultant sulfur  tricxide  (SO3)   gas.  In  turn,  the
sulfur trioxide  (SO3) gas is hydrolyzed by the addition of water to form
sulfuric acid  (H2S04).

Prior  to  1930 the contact process was used primarily in Europe for the
manufacture of high strength sulfuric acid (98 + %)  and  oleums.   From
this  date  forward,  American process innovations improved materials of
construction and operating costs to the point that  the  process  became
the  most  economical  method  of producing sulfuric acid from elemental
sulfur.  In addition to  these  factors,  the  process  is  designed  to
capture  a  high  percentage  of  the  energy released by the exothermic
chemical reactions occurring in the oxidation of sulfur   (S)  to  sulfur
trioxide   (SO3J .   This  energy  is  used to produce steam which is then
utilized for other plant unit  operations  or  converted  to  electrical
energy.   It is the raw water treatment necessary to condition water for
this steam production that generates essentially all the water  effluent
from this process.

In  the  period  between 1930 and 1971, practically all contact sulfuric
acid plants built in the U.S. were designed with a  "single  absorption"
step  (see Figure 3).  The term "single absorption" refers to the process
point  when  sulfur  trioxide  (SO3J gas is hydrolyzed with water to form
product sulfuric acid  (H2S04J .  This process step  is performed after the
gas has passed through all  the  catalysis  stages.   Exit  gas  from  a
"single  absorption"  stage generally contains sulfur dioxide  (SO2) at a
concentration  level appreciably in excess of the standard established by
EPA of 1.81 kg/kkg  (4.0  lb/  ton)  100%  acid  produced.   Since  1971,
however,  a  process  modification  is  being  offered  which will allow
compliance to  the EPA standard.  The modification  is the addition  of  a
second  absorption  step and is known as the "double absorption" process
 (Figure 4).  It  is most likely that all future plants will  utilize  the
double  absorption  technique.   Such  a  process  modification will not
affect the characteristics or quantity  of  sulfuric  acid  plant  water
effluent in any  manner.

Process -  Single Absorption

The  raw   materials  used to produce sulfuric acid by the contact  method
are elemental  sulfur, air and water.  Molten elemental  sulfur  is sprayed
into  a  dry   air  stream  inside  a  furnace.   The  elevated   furnace
temperature  auto-ignites  the  atomized  liquid sulfur to  oxidize it to
sulfur dioxide (S02) .  This reaction releases a large quantity   of heat
                                      24

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QC
LU

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which  causes  the temperature of the resultant S02 - excess air mixture
to rise to 980 - 11UO°C  (1800-2000°F) as it exits from the furnace.  The
heated gas mixture flews to a boiler for heat removal.  Sufficient  heat
is removed to reduce the gas mixture temperature to the initial reaction
condition for optimum chemical conversion of S02 to S03.

SO2  conversion  to  SO3 takes place in a series of three or four steps.
Each conversion step takes place under a a different reaction  condition
to  achieve  the  most complete conversion of SO2 to SO3_ possible.  This
conversion efficiency in a single absorption  process  is  approximately
98%.

Following  the  conversion stages, the SO3 gas flows to the bottom of an
absorption tower.  In the tower the SO3 gas flows upward through ceramic
packing and counter-cur rent to downward flowing 98-99% H2SO*t.   The  SO3_
is  readily hydrolyzed to H2SO4 by the water in the acid.  Hydrolysis of
the SO3_ to H2SOJ4 also releases heat which increases the  temperature  of
the enriched 98-99% H2SCJ4 acid.  After the acid exits the tower it flows
through cooling coils tc offset the temperature increase and then to the
pump  tank.   From this tank it is again recycled through the absorption
tower.

At the start of the process discussion, it was mentioned that the molten
sulfur is burned in a dry air stream.  The drying of the atmospheric air
used in the process is accomplished in the  drying  tower.   Here  moist
atmospheric  air  enters the base of the tower and flows upward counter-*-
currently to concentrated sulfuric acid pumped from the pump tank.  This
acid has, however, been diluted from the normal 98-99% H2SOU acid in the
pump tank to approximately 93%.   The  resultant  moist  air,  93%  acid
contact,  removes  moisture  from  the air stream yielding dry air and a
slightly further diluted acid.  In turn the dry air flows to the furnace
and the diluted acid flews back to the pump tank  for  mixing  with  the
stronger 98-99% acid flowing back from the SO3 absorption tower.

The  product  is that acid flowing intc the pump tank which is in excess
of drying and absorbing tower recycle requirements.  Adjustments to  the
rate  of  product  acid  removal  from  the  pump tank are determined by
monitoring the pump tank level and maintaining it at a  constant  level.
The  excess  (product)  acid is diluted with water to the desired product
acid concentration (normally 93% H2SO4) before it is pumped to storage.

Process - Double Absorption

As previously mentioned it is most likely that all new plants  built  in
the United States in the future will be double absorption process units.
The   feature  which  makes  this  process  different  from  the  single
absorption  process  described  above  is  the  addition  of  a   second
absorption   tower.    This   second  tower  is  installed  at  a  point
intermediate between the first and final SO2 to SO3 catalytic conversion
steps.   Utilization  of  this  second  absorption  tower  permits   the
achievement  of a greater SO2 conversion to SO_3 and thus a significantly
reduced quantity of S02  in  the  plant  effluent  gas  stream.   Double
absorption  plants  realize  SO2  conversion  efficiencies of 99.5+ % as
                                     27

-------
compared to single absorption plant efficiencies of  approximately  98%.
Both  processes have the same water effluent in respect to both quantity
and contaminant levels.
                                     28

-------
             Phosphate_Pock Grinding - Process Descrip-tion
General
Phosphate rock that has been mined and  beneficiated  is  generally  too
coarse  to be vised directly in acidulation to phosphoric acid.  The rock
is, therefore, processed through equipment to mechanically reduce it  to
the  particle  size  required  for optimum phosphoric acid plant process
efficiency.

Process

Size reduction is accomplished with ball, roll or bowl mills.  Phosphate
rock is fed into the irills and mechanically ground  (Figure  5) .   After
the  rock  enters  the  mill  system,  all  flow  through the sizing and
reclamation circuits is by pneumatic means.  Air is constantly exhausted
from the mill system to prevent precipitation of moisture generated from
the rock as a result of grinding.   Normally,  the  exhaust  air  passes
through  a  bag  type  air cleaner to remove entrained rock particulates
before discharge to the atmosphere.

Phosphate rock size reduction in all existing fertilizer  plants  is  an
entirely  dry  processing  circuit  and does not directly involve liquid
streams.  Minor quantities of water are used  for  indirect  cooling  of
lubricating oil and mechanical equipment such as bearings.

Some future rock grinding operations will utilize a wet grinding circuit
rather  than the current dry grinding practice.  This change is prompted
by a combination of Icwer capital costs and the elimination of  the  gas
effluent  streams  associated  with  both  the  rock drying and grinding
operations.  Use of  this  new  technique  will  not  change  the  self-
contained  nature of the rock grinding circuit.  There will be no liquid
effluents other than those mentioned in the dry grinding process.
                                     29

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                 Phosphate Rock_Digestj8pn 6 Filtration

                          Process Description
General
Phosphoric acid is the basic building block from which  essentially  all
mixed fertilizer used in the U.S. is made.  The overwhelming majority of
this  acid  is  manufactured  by  the  wet  process method.  The process
involves changing the state of the phosphate content in  phosphate  rock
from a practically water insoluble tc a water soluble compound.  This is
accomplished  by  solubilizing  the phosphate rock with a highly ionized
acid.  Acid type is selected through a combination of factors  including
cost,  simplicity of process, materials of construction, and the desired
end products.  In the U.S., sulfuric acid is by far  the  most  commonly
used  acid,  but  other  acids,  such as nitric and hydrochloric, can be
utilized.

A statistical compilation of U.S. phosphoric  acid  producers  is  shown
below.   The figures shew the relative importance of the three mentioned
acid treatment processes and indicates the most prominent process.

                                            Annual
     Type of Acidulation  Number of Operat- P2O5      % of Total
          Process;;
     Sulfuric Acid              35*         4,879,000    98.77

     Nitric Acid                 4             61,000     1.23

     Hydrochloric Acid           0                  00
                                39          4,940,000   100.00%

          ""Including three plants restarted in 1973.

All the  acidulation  processes  have  inherent  problems  with  process
effluents,  both  gaseous  and  water,  as  well as by-product disposal.
Successful and acceptable by-product storage  and  processing  of  plant
effluents  is  to  a large degree dependent upon the considerations made
for such items during the original plant layout stages.  It is much more
difficult and possibly economically impractical in  some  cases  to  add
such  facilities  to  an existing plant.  Sizable acreage and reasonably
good soil compaction characteristics are required to handle the effluent
and by-product processing arrangements.  Those plants located  in  areas
where land is not available and/or soil stability is poor are at a great
disadvantage.   Particular  reference is to those installations in Texas
and Louisiana.
                                     31

-------
                            Phosphoric Acid

                          Process Description

Sulfuric Acid Acidulaticn

The raw materials used in this process are ground  phosphate  rock,  93%
sulfuric  acid,  and  water.   Phosphate rock is mixed with the sulfuric
acid after the acid has first been diluted with water to a 55-70%  H2_so^
concentration.    This  mixing  takes  place  in  an  attack  vessel  of
sufficient size to retain the raw material  mixture  for  several  hours
(Figure  6).   The simplified overall chemical reaction is represented by
the following equation:

     3 Ca3 (POM) 2 (solid)    +    9 H2SOU  (liq)   + 18 H2O  (liq) 	^
         Phos. Rock                  Sulf. Acid     Water

      6 H3POU  (liq)   +   9 CaSO4  .  2H20  (solid)
         Phos. Acid          gypsum

In reality phosphate rock is not the pure compound indicated above,  but
a  fluorapitite  material containing minor quantities of fluorine, iron,
aluminum, silica and uranium.  Of these  the  one  presenting  the  most
serious  overall  process problem is fluorine.   Fluorine is evolved from
the attack vessel and  ether  plant  equipment  as  either  the  gaseous
compound  silicon  tetrafluoride  (SiF4) or hydrofluoric acid (HF).  SiF4
hydrolyzes very quickly in moist air to fluosilicic  acid   (H^SiF6)  and
silica  (SiO2). Both SiF4 and HF can be collected in a wet scrubber unit.

Additional   fluorine  remains  in  the by-product gypsum in a variety of
fluorine compounds.  The combination,  therefore,  of  absorbed  gaseous
fluorine effluent and the soluble fluorine compounds in the gypsum are a
major contaminant in the phosphoric acid plant effluent streams.

Following  the  reaction in the digestor, the mixture of phosphoric acid
and gypsum is pumped  to  a  filter  which  mechanically  separates  the
particulate   gypsum   from  the  phosphoric  acid   (approx.   30%  P2O5
concentration).  The magnitude of the by-product gypsum is best appreci-
ated by the  fact that the production of each kkg of P2O5  as  phosphoric
acid  creates approximately five  (5) kkg of gypsum.  Normally the gypsum
is sluiced with contaminated water from the plant to  a  disposal  area.
The  phosphoric  acid separated from the gypsum is collected for further
processing.
                                      32

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                            Phos]ghoric_Acid

                          Process_Descri2tion
Nitric Acid Acidulaticn
There are two different nitric acid  acidulation  processes  which  have
been  used  commercially  in  the  United States.  One of these has been
discontinued within the past year and currently only one is  being  used
for fertilizer production.

Nitric  acid  acidulaticn  differs  frcm  the  sulfuric acid acidulation
process in that phosphoric acid is not separated as a product  from  the
acidulation  reaction  mixture.   Consequently,  the division of process
steps between acidulaticn  and  the  final  fertilizer  product  is  not
possible.

The  raw  materials  used  are generally unground phosphate rock and 57%
nitric acid.  Nitric acid and the rock are mixed together  in  a  series
(12-15)  of  violently  agitated  small reactor vessels  (Figure 7).  The
first few vessels serve primarily to dissolve the rock according to  the
following chemical reaction.

     Ca3(P04)2  +  6HN03	» 3Ca (NO3) 2  +  2H3PO4
     Phos. Rock   Nitric Acid     Calcium      Phos. Acid
                                  Nitrate

This  reaction  essentially  places  both the reaction products, calcium
nitrate and phosphoric acid, in a mixed  liquid  form.   At  this  point
either  purchased  phosphoric  or  sulfuric acid is added to the process
together with ammonia to produce a specific mix  of  calcium  compounds,
ammonium  nitrate,  and phosphoric acid.  This mixture is then converted
to a dry product.  The fertilizer grades produced from this mixture  are
limited both as to number and water soluble phosphate content.
                                      34

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                     Fhcsphoric_Acid^Concentratign

                          Process Description
General
Phosphoric  acid as produced in the sulfuric acid acidulation process is
generally of too low a concentration (26-30* P2O5)  to qualify as  either
a  salable  product  cr to be used for processing a final dry fertilizer
product.  This P2O5 level can be increased in the 40-54% P2O^  range  by
processing the acid through water evaporator units.

Process

Phosphoric acid concentration to 5451 2205 is performed with low pressure
steam  as  the  heat energy source for the evaporation of water from the
acid.  Evaporation is accomplished by circulating acid at a high  volume
rate  consecutively  through a shell and tube heat exchanger and a flash
chamber under vacuum pressure conditions.  The flash chamber  serves  to
provide  a comparatively large liquid surface area where water vapor can
be easily released without incurring  significant  phosphoric  acid  en-
trainment  losses.   Inherent with the water evaporation is also volati-
lization of minor acid impurities, the  principal  one  being  fluorine.
The  evolved  fluorine together with very minor quantities of phosphoric
acid pass to a barometric condenser and contaminate the condenser water.
                                      36

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                     Phosphoric Acid Clarification

                          Process Description


General

Phosphoric acid after concentration to a 52-5456  ^2OS  level  becomes  a
supersaturated  solution  to  a variety of minor acid impurities, namely
iron and aluminum phosphates, soluble gypsum, and fluosilicates.    These
impurities are present in quantities sufficient to create an appreciable
solids  accumulation  during acid storage.  In turn this causes tank car
unloading and customer processing problems.  It is, therefore, necessary
to  remove  these  precipitated  impurities  before  the  acid  can   be
considered a salable product.

Process

The process used in the U.S. for removal of precipitated solids from 54%
P2O5 phosphoric acid involves only physical treatment of the acid rather
than  the  more  complicated  and expensive solvent extraction processes
utilized in Europe and Mexico  (Figure 9).  The acid  is  conditioned  at
the  proper  temperature  and  time  necessary  to realize the degree of
solids  precipitation  required  to  meet  the  clarified  acid  product
specifications.    The   precipitated  impurities  are  then  physically
separated from the acid by settling and/or centrifugation.

Water usage in this process is limited to indirect cooling of  the  acid
and minor quantities for equipment washing.
                                     38

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                         Normal^Superphosphate

                          Process Description
General
Normal  superphosphate  was,   for  many  years,   by far the most popular
phosphate fertilizer.  Since the mid-fifties,  however,   this  popularity
has  been in a sharp decline and only in the past few years has the rate
of decline started to moderate.  The market share of this fertilizer has
fallen from 68* in 1957 to 42% in 1965 and now appears leveling  off  at
approximately  18%.   The  major  reasons  for this decline include such
items as low P2O5 content (20%) with the associated  increased  cost  of
transportation per ton of nutrient and the trend to larger size plants.

Normal  superphosphate  can  be manufactured in small inexpensive plants
with low production costs per ton of P2O5_.  The process  is  simple  and
easy  to  operate  requiring  less  sulfur  per  ton  of  P2O5  than the
production of phosphoric acid.  The coirbination of  low  investment  and
simplicity together with recognition of the adverse fertilization effect
of  sulfur  deficiency  in  the  soil assures that normal superphosphate
production will not die out but sales will be  limited  to  an  area  in
close proximity to the plant site.

Proces_s

The  two  raw  materials used in the production of normal superphosphate
are 65-75% sulfuric acid and ground phosphate  rock.   Reaction  between
these  two  materials  is  both highly exothermic and rapid (Figure 10).
The basic chemical reaction is shown by the following equation:

     Ca3(P04)2  +  2H2SOU  +  H2O	>2CaSO4.2H20 + Ca (H2PO4).H2O
     Phosphate     Sulfuric   Water     Gypsum      Normal Superphos-
     Rock          Acid                             phate


The interval of fluidity before the two reactants solidify is very brief
and the mixture is quickly transferred to an enclosed space referred  to
as a den.  This den may be either an essentially stationary structure or
a  continuous  slow  moving  conveyor.   In the den the material becomes
plastic relatively quickly.   During  this  phase  there  is  a  copious
evolution  of  obnoxious  gas as the crystallization process progresses.
Retention time in the den can range from 1 to 4 hours dependent  on  the
overall  process  conditions.   At  the  end  of  this time the material
becomes a porous mass resembling a honeycomb and is removed from the den
to storage.  A storage period of  3 to 8 weeks is required  for  "curing"
before  the normal superphosphate is an acceptable product for shipment.
The "curing" time serves to allow completion of  the  chemical  reaction
between  the rock and acid with the subsequent decrease  in free acid and
citrate insoluble P2O5 content.
                                     40

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                         Triple^Superghosphate

                          Process Description

General

Triple superphosphate (ISP), with its 46.0% - 48.5% P2O5 content,  is  a
high analysis phosphate fertilizer.  As such, it provides transportation
economy  which  has  been  instrumental  in  enlarging  its share of the
phosphatic fertilizer market.

This product has in the 1950-1965 period taken over much of  the  market
lost  by  normal superphosphate and currently accounts for approximately
24% of the total phosphatic  fertilizer  market.   TSP's  share  of  the
market  for  the  near  future is expected to remain relatively constant
primarily because of the tremendous growth of the  ammonium  phosphates.
TSP  production,  unlike normal superphosphate, can be most economically
produced close to the phosphate rock source.  In  the  U.S.  this  means
that  approximately  83%  of  the  total  production  is manufactured in
Florida.

Process

There are two principal types of TSP,  Run-of-Pile  (ROP)  and  Granular
Triple  Superphosphate   (GTSP).  Physical characteristics and processing
conditions of the two materials are radically different.   ROP  material
is essentially a non-uniform pulverized material which creates difficult
air  pollution  problems  in  manufacture as well as difficult materials
handling problems in shipment.  GTSP  is  a  hard,  uniform,  pelletized
granule produced in process equipment which permits ready collection and
treatment  of  dust and obnoxious fumes.  Most new plants will be of the
GTSP type.

Both processes utilize the same raw materials, ground phosphate rock and
phosphoric acid.  The basic chemical reaction is shown by the  following
equation:

  Ca3  (PO4) 2  +  4H3_PC4  + 3H2O	>3Ca (H2PO4.) 2 . H2O
  Phosphate      Phosphoric Water      Triple Superphosphate
  Reck           Acid                   (Monocalcium phosphate)

At this point the similarity between the two processes ends.

The  ROP  process  is essentially identical to  the normal  superphosphate
process with the exception that phosphoric rather than sulfuric  acid  is
used  as  the  acidulating  acid  (Figure 11).   Mixing of the  46-54% P2O5
phosphoric acid and phosphate rock normally is  done  in  a  cone  mixer.
The  cone  depends  solely on the inertial energy of the acid for mixing
power.  On discharge from the  mixer  the  slurry  quickly   (15-30  sec)
becomes  plastic  and  begins to solidify.  Solidification together with
the evoluation of much obnoxious  gas  takes   place  on  a  slow moving
conveyor   (den)  enroute  to  the  curing area.  The solidified  material
because of the gas evolution throughout the mass takes   on  a  honeycomb
                                     42

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appearance.   At. the point of discharge from the den the material passes
through a rotary mechanical cutter which breaks up the  honeycombed  ROP
before  it  discharges onto the storage (curing)  pile.  Curing occurs in
the storage pile and takes 2-4 weeks before  the  ROP  is  ready  to  be
reclaimed from storage, sized and shipped.

GTSP  is produced quite differently (Figure 12).  The phosphoric acid in
this process is appreciably lower in concentration (40% P2O5)   than  the
46-54%  Pj2°.5  acid used in ROP manufacture.  Forty percent P2O5 acid and
ground phosphate rock are mixed together in an agitated tank.   The lower
strength acid maintains the resultant slurry in a fluid state and allows
the chemical reaction tc proceed appreciably further  toward  completion
before it  solidifies.  After a mixing period of 1-2 hours the slurry is
distributed  onto  recycled  dry  GTSP  material.  This distribution and
mixing with the dry GTSP takes place in either a pug  mill  or  rotating
drum.   Slurry  wetted  GTSP granules then discharge into a rotary drier
where the chemical reaction is accelerated and essentially completed  by
the  drier  heat while excess water is being evaporated.  Dried granules
from the drier are sized on  vibrating  screens.   Over  and  under-size
granules  are  separated  for  use  as  recycle  material.  Product size
granules are cooled and conveyed to storage or shipped directly.
                                     44

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                          Ajmmo^ium Phosphates

                          Process Description

General

The ammonium phosphate fertilizers are highly  concentrated  sources  of
water  soluble  plant  food  which  have  had a spectacular agricultural
acceptance in the past twenty years.  Production capacity of  diammonium
phosphate  (DAP)   has  increased  at a compounded rate of 19.8% annually
over the last ten years.  The  popularity  of  the  ammonium  phosphates
results  from  a  combination  of  factors.   These  include  the  ready
adaptability of the production processes to ever increasing single plant
capacities with  their  associated  lower  production  costs;  favorable
physical  characteristics  which  facilitate storage, handling, shipping
and  soil  application;  compatibility  with   all   common   fertilizer
materials;  transportation  economies  effected  by the shipment of high
nitrogen  (18%N) and phosphate (46% P2O5)  nutrient content  at  a  single
product cost; and the ability of an N-P-K fertilizer producer to realize
up  to  twice  the  profit  margin  per  kkg  of P205 from DAP than from
concentrated superphosphate.  Such an impressive number of plus  factors
insure  that  ammoniurn  phosphate  processing   (particularly  DAP)   will
continue to be an important segment of the fertilizer industry.

Ammonium  phosphate  fertilizers  include   a   variety   of   different
formulations  which  vary  only in the amounts of nitrogen and phosphate
present.  The most important ammonium phosphate fertilizers  in  use  in
the U.S. are:

             Monoammonium	(MAP]	Phosphates
                  11~- 48-0
                  13-52-0
                  11-55-0
                  16-20-0

              Diammonium Phosphates	(DAP]_
                  16-48-0
                  18-46-0

Diammonium   phosphate  formulations are produced in  the largest tonnages
with DAP  (18-46-0) being the most dominant.

Process

The two primary raw materials used to produce   ammonium   phosphates  are
ammonia   and wet process phosphoric acid.  Sulfuric  acid  is  of secondary
importance but is used in the production of the  monoammonium  phosphate
grade  16-20-0.  As mentioned above, the various grades vary only in the
amounts of nitrogen and phosphate present.  It  is primarily  the nitrogen
that varies  and this  is  accomplished  by  controlling   the  degree  of
ammoniation  during neutralization of the phosphoric acid.   The chemical
reactions involved are indicated by the following equations:
                                     46

-------
     H3P04    +    NH 3   _ ^ NH4H2P04
     Phosphoric   Ammonia       ^ Monoammonium
     Acid                         Phosphate

   * H2S04    *   2NH3  _ ^ (NH4) 2SO4
     Sulfuric     Ammonia         Ammonium
     Acid                         Sulfate

*  This reaction occurs only in the production of 16-20-0 and
occurs concurrently with the monoammonium phosphate reaction.
The processing steps (Figures 13 and 14)  are  essentially  identical  to
those  described  in  the  triple superphosphate GTSP process.   Ammonia,
either gaseous or liquid, is reacted with 30-40% P2O5 phosphoric acid in
a vertical cylindrical vessel which  may  or  may  not  have  mechanical
agitation.   The  resultant slurry is then pumped to a mixer where it is
distributed onto dry recycled material.  Distribution and  mixing  takes
place  in  either  a  pug  mill  or rotating drum.  Wetted granules then
discharge into a rotary drier where  the  excess  water  is  evaporated.
Dried  granules are separated for use as recycle material.  Product size
granules are cooled and conveyed to storage or shipped directly.
                                     47

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Ni;trogen_Fertilizer Industry

The nitrogen fertilizer industry  is  composed  of  four  basic  process
plants:   ammonia,  urea,  ammonium nitrate and nitric acid.  Ammonia is
the basic nitrogen fertilizer constituent.  It can either be used as the
raw material feed stock for urea ammonium nitrate and nitric acid or  it
can  be  used  directly  as a fertilizer providing the highest amoun-t- of
available nitrogen per kkg of any of the nitrogen fertilizers.

For the most part, nitrogen fertilizer plants exist, or will  be  built,
without  the  interference of a phosphate fertilizer plant.  That is, if
there happens to be phosphate fertilizer units at the same plant site as
nitrogen fertilizer units, they are or would be  sufficiently  separated
so  that their waste water effluent streams can be treated individually.
However, the nitrogen fertilizer plants, in many cases, are very closely
integrated and their waste water effluent streams intermixed.


The dependency of the three other plants on an ammonia plant can be seer.
from the process descriptions.   Although  there  are  isolated  ammonia
plants  there are few cases where any of the other process plants, whose
production goes for nitrogen fertilizers, exist by themselves.  A nitric
acid plant will be at the same site as an ammonium nitrate plant and  an
urea  plant will be located next to an ammonia plant.  In many cases all
four of these plants will be at the same plant site.   (See Table 1).

                                Ammonia

                          Process Description

Ammonia, being the base component for the nitrogen fertilizer  industry,
is  produced  in  larger  quantities  than  any other inorganic chemical
except sulfuric acid.  The total U.S. production in 1971 was  16,000,000
kkg   (17,650,000  short  tons)  with  an  expected  1972  total close to
16,500,000 kkg  (18,200,000 short tons).  The size of  an  ammonia  plant
will range from less than 90 kkg/day  (100 tons/day) to larger than 1,360
kkg/day  (1,500 tons/day) with the newer plants being the laraer sizes.

Ammonia is produced by the reaction of hydrogen with nitrogen in a three
to one  (3:1) volume  (irole) ratio.

          N2 +  3H2 	>2NH3

This  reaction  is carried out in the presence of an iron promoted metal
oxide catalyst at elevated pressure, which favors the ammonia formation,
in a  special reaction vessel  (converter)  (Figure 15).  Pressure  in  the
converter  will  range from 130 atm  (1930 psig) to  680 atm  (10,100 psia)
for the smaller plants, less than  550  kkg/day   (600  tons/day),  using
reciprocating  compresscrs to operate at higher pressures and for  larger
plants, greater than 550 kkg/day   (600  tons/day),  operating  at  lower
pressures  using  centrifugal  machines   for  gas  (syn gas)  compression.
This  reaction is  exothermic and care must be taken  to obtain the optimum
temperature which favors  both  the  ammonia  equilibrium   and  rate of
                                     50

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reaction.   Most  of  the ammonia converters will operate at temperature
from 338°C (550°F)  to 421°C (700°F) .

Since at these operating conditions,   the  conversion  of  hydrogen  and
nitrogen  to  ammonia  is  on  the  order  of 10% to 20%, a considerable
quantity of reaction gas   (hydrogen,   nitrogen,  methane,  argon,  other
inerts,  and  ammonia)  must be cooled to condense ammonia, recompressed,
mixed with fresh make-up gas (syn gas)  and reheated for recycle  to  the
ammonia converter.

The ammonia product, after pressure reduction, is stored in either large
atmospheric  tanks at a temperature of -33°C  (-28°F)  or in large spheres
or bullets at pressures up to 20 atm (300 psig) at ambient temperatures.

The above process description normally describes the "back  end"  of  an
ammonia plant, the airrronia synthesis section, with the "front end" being
designed  for  the  production  of  the syn gas  (make-up feed to ammonia
synthesis section) .  The "front end" of an ammonia plant may range  from
a  very  simple  gas  mixing operation to a very complex gas preparation
operation depending on the raw materials used.  The raw material  source
of  nitrogen  is atmospheric air and it may be used in its natural state
as compressed air to a gas preparation unit or as pure nitrogen from  an
air  plant  to  a  gas  mixing  unit.  Hydrogen,  on  the other hand, is
available from a variety of sources such  as:   refinery  off-gas,  coke
oven off-gas, natural gas, naphtha, fuel oil, crude oil and electrolytic
hydrogen  off -gas.    At  the  present  time,  more than 92% of the total
ammonia produced in the United States uses natural gas as  its  hydrogen
source  and  feed  to  a   gas preparation unit, better known as a steam-
methane reforming unit.

Since the steam-methane reforming unit is the most widely used  for  syn
gas preparation, its process description will be used for describing the
"front  end".   The  steam-methane  reforming  "front end" can be divided
into the following:

     a.  Sulfur Removal 5  Gas Reforming

     b.  Shift Conversion

     c.  CO2 Removal

     d.  Methanation

In the sulfur removal and  gas reforming  section, natural gas  at  medium
pressures  14  atm   (200 psig to 600 psig) is  treated for the removal of
sulfur and other high molecular weight hydrocarbons by passing  the  gas
through  a  bed of  activated carbon.  The natural gas is then mixed with
steam and heated before being passed through  a bed of nickel catalyst in
the primary reformer.  In  the  primary  reformer  the   natural  gas  is
reacted  at temperatures around 790°C  (1,U50°F)  with the steam according
to the following reactions:
     CxHy. + H2O - >xCO +  (y + y/2) H2  (Reform)
                                      52

-------
     CO + H2O 	^ CO2 + H2 (Shift Conversion)

The reforming reacticr is only partially complete  and  the  shift  con-
version  reaction  proceeds only as far as the operating temperature and
pressure will permit.

The next piece of process equipment,   the  secondary  reformer,  is  the
location  for  the  introduction  of  nitrogen  as  compressed  air at a
quantity that will result in a 3:1 volume ratio (hydrogen  to  nitrogen)
in  the  final syn gas.  The reactions which occur are the completion of
the reforming reaction above and the oxidation of  hydrogen  to  consum^
the oxygen in the compressed air feed.  One result of these reactions is
an  exit temperature in excess of 930°C (1,700°F).  These hot gases then
enter a high pressure steam boiler, 41 atm to 102 atm (600 psig to 1,500
psig), and then into the shift conversion section.  The  shift  reaction
(see  above)  is  favored  by low temperatures and is carried out in two
steps with heat recovery  between  each  step.   The  first  step,  hiah
temperature  shift conversion, is carried out by passing the gas through
a bed of iron oxide catalyst while  the  second  step,  low  temperature
shift  conversion,  takes  place  in  conjunction  with  a copper, zinc,
chromium oxide catalyst at temperatures around 220°C  (425°F).  Following
additional heat recovery and cooling, where necessary, the gas passes to
the CO2 recovery section.

The CO2 recovery system is not complicated, but there are  a  number  of
types  of  systems  available  and  each  one  has  its  advantages  and
disadvantages.  The two systems most used in the U.S. are one  based  on
monoethanolamine  (MEA)  and a second one based on hot potassium carbonate
and  its  variations.   In  each  of  these cases a circulating solution
either absorbs or reacts with the CO2 in the  gas  stream  reducing  its
concentration  below 0.1%.  The CO2 rich solution is then regenerated in
a stripper using previously recovered heat with the CO2 and  some  water
vapor being exhausted to the atmosphere.

The final stage in syn gas preparation is to remove any traces of CO and
C02 remaining.  This is accomplished in a methanation unit where the gas
is  passed  through  a bed of nickel catalyst resulting in the following
reactions:

                               + H20

                               + H20

After heat recovery and any necessary cooling the syn gas is  ready  for
compression and feeding to the ammonia synthesis section.
                                     53

-------
                                  Urea

                          Process_pescrigtion

Urea  is  another  major  source  of nitrogen fertilizer produced in the
United States.  Some 4,900,000 kkg  (5,400,000 short tons)  of  urea  were
produced in the U.S. in 1971.

Basically,  there  are  three  urea  production  processes  which differ
primarily in the way  the  unreacted  ammonia  and  carbon  dioxide  are
handled.
     A.  Once-through Process - In this process, no attempt
         is made to recycle these gases to the urea process.
         The off-gases containing ammonia and carbon dioxide are
         used in the production of fertilizer products.

    B.   Partial Recycle Process - Excess ammonia is recycled
         back to the process while any excess carbon dioxide is
         vented to the atmosphere or used in another process.

    C.   Total Recycle Process - Both the ammonia and carbon dioxide
         in the off-gas are recycled back to the urea process.

Currently,  the  total  urea  production  is  divided  as follows:  once
through, 18%; partial recycle, 12%; and total recycle, 70%.

All of the urea production in the  United  States  is  produced  by  the
reaction  of  ammonia with carbon dioxide which forms ammonium carbamate
(Figure 16).  The ammonium carbamate is then dehydrated to form urea.

    2NH3 + CO2 	>NH4CC2NH2

    NH4C02NH2 	>NH2CONH2 + H2O

Most urea plants are located at the same plant site as a correspondingly
sized ammonia plant. The ammonia plant  not  only  supplies  the  needed
ammonia, but also the high purity carbon dioxide.

The carbon dioxide-ammonia reaction to form urea, ammonium carbamate and
water  takes place in a reactor vessel at pressures ranging from 137 atm
(2,000 psig) to 341 atm  (5,000 psig)  and  at  temperatures  from  121°C
(250°F) to 182°C  (360°F).  Unreacted ammonia and carbon dioxide are also
present  in  the reactor exit stream.  The carbamate forming reaction is
highly exothermic while the carbamate dehydration reaction  is  slightly
endothermic.    Under  reactor  operating  conditions,  the  dehydration
reaction proceeds to 40% to 60% completion resulting in an  overall  net
exothermic heat effect.  After separation of the ammonia, carbon dioxide
and  ammonium carbamate, the resulting solution will be about 70% to 80%
urea.  Depending upon product specification this 70-80% solution can  be
used  as  is or it can te further concentrated to a solid product.  This
solid product can be formed by prilling, crystallation or a  combination
of  both.   The  concentration  step  takes  place  in flash evaporators
designed with minimum residence time to prevent the formation of biuret.
                                     54

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-------
(NH2CCNHCONH2 • H20)   This biuret has a deleterous effect on crops.  The
basic disadvantage in selecting prilling  versus  crystallization  or  a
combination is the degree of biuret formation.  Prilling gives a product
with  about  1% biuret while crystallization only has .1*. A combination
of the two processes results in a biuret content of about .5%.
                                      56

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                            Ammonium Nitrate

                          Process Description

Ammonium nitrate is a major source of nitrogen fertilizer in the  United
States.   The  total  production  in  the U.S. in 1971 was 7,800,000 kkg
(8,600,000 short tons).  It is an excellent  fertilizer  being  high  in
nitrogen  (35%)  and relatively low in cost.

Ammonium nitrate is made by reacting ammonia with nitric acid:

          NH3 + HNO3	>NH4NO3

This  reaction  is  carried  out  in  a  low  pressure vessel called the
neutralizer (Figure  17).   The  high  heat  of  reaction  causes  flash
vaporization  of  water  with  some  ammonia  and nitrate going overhead
leaving behind a liquid product which is 8356 by weight ammonium nitrate.
This product known as AN solution can be  sold  or  it  can  be  further
processed  into a dry product.  The overhead vapors from the neutralizer
may lead to an air pollution problem or if condensed, will  have  to  be
treated before being discharged.

If  a  dried  product  is  desired,  then  the  83% AN solution is first
concentrated up to 95% AN and then either prilled or  crystallized.    If
prills  are  to  be  the  final  form  of the ammonium nitrate, the con-
centrated solution is pumped to the top of a 45 meter (150  ft.)   to  61
meter  (200 ft.) tower where it is sprayed downward into a rising flow of
air.   As  the ammonium nitrate droplet forms it is solidified before it
hits the bottom of the tower.  These prills are then  further  dried  to
reduce  the  moisture  to less than 0.5%.  Following cooling, the prills
are then coated with an anti-caking agent such  as  clay.   Concentrator
and  prill  tower  air  exhausts can contain significant amounts of fine
particulate ammonium nitrate which represents  both  a  significant  air
pollution  problem and an indirect water pollution source via runoff and
washoff.

A final dry crystalline  ammonium  nitrate  product  requires  that  the
solution  from  the  concentrator  (95% AN) be fed to a continuous vacuum
evaporation  crystallizer.    The  cooling  of  the   solution   in   the
crystallizer causes crystals to form.  A side stream of crystal solution
is  taken  from  the  crystallizer  and  fed to a centrifuge for crystal
separation.   The  centrifuge  supernate  is  recycled   back   to   the
crystallizer.    The  crystals  are removed from the centrifuge, dried to
less than 0.1% water, cooled and coated with an anti-caking agent.
                                     57

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                              Nitric_Acid

                          Process Description

Nitric acid is produced by a number of processes in strengths  from  55%
to  100%  acid.   In 1971 there were some 8,450,000 kkg (9,300,000 short
tons)  of acid produced of which better than  80%  was  used  for  and/or
produced  at  nitrogen fertilizer complexes.  While varying strengths of
acid are produced, the fertilizer industry uses a dilute  acid  (55%  to
65%) .

Nitric  acid  is  produced in the United States by the ammonia oxidation
process  (Figure 18).  In this process, ammonia is reacted  with  air  to
produce  oxides of nitrcgen which are then further oxidized and absorbed
in water producing a 55 to 65% nitric  acid.   The  following  reactions
occur in the process:


     2NO + 02	>2N02

    3NO2 + H2O	^2HNC3 + NO
The  initial  ammonia oxidation reaction takes place in the converter in
the presence of a platinum-rhodium  gauze  catalyst  at  pressures  from
atmospheric  up to 82 atm  (120 psig).  The exit gases from the converter
may be in the temperature range of 705°C (1,300°F)   to  980°C  (1,800°F)
and are used to superheat steam and preheat process air.  The gases then
pass  through  a  waste  heat  boiler  to  generate  steam  for  the air
compressor  drive  turbine  and  for  export.   The  quantity  of  steam
generated  by  the process will range from 500 to 1,000 kg/kkg (1,000 to
2,000  Ib/ton)  of  nitric  acid.   By  this  time,  due  to  the  lower
temperature, the second reaction involving the oxidation of nitric oxide
to  nitrogen  dioxide  has  begun  to  occur.  Following some additional
cooling to 38-49°C (100-120°F), where seme of the water is condensed and
forms nitric acid, the gases are passed up through an absorption column.
Some additional air is also passed up through the column to oxidize  the
nitric  oxide  formed  during  the  absorption step to nitrogen dioxide.
Water (fed to the top of the absorber)  acts  as  the  absorbant  giving
product  nitric  acid  cut  the  bottom  of  the  column.   The absorber
temperature is held constant by cooling water to improve the  absorption
efficiency.   Cooling  water  requirements  will  range from 104,000  to
146,000 1/kkg  (25,000  to 35,000 gal/ten) of product.

The gases leaving the top of the absorber are  fairly  low  in  nitrogen
oxides  but  may be catalytically reacted to further reduce these levels
and, then depending on the process pressure, passed through  a  hot  gas
expander  to  recover some of the energy needed to drive the process air
compressor.  The differential energy required for the air compressor can
be supplied by a helper turbine driven by the  steam  generated  by  the
process.
                                     59

-------
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                               SECTION IV
                        INDUSTRY_CATEGORIZATigN

The  task  of  dividing  the  many  fertilizer  processes  into specific
categories was considered one of  the  most  important  aspects  of  the
study.   A particular objective was to have the least possible number of
categories in order to simplify the work of both  enforcement  officials
and industry in the monitoring of effluent streams.

The  factors  considered  in the overall categorization process included
the following:

    1.   Industry division
    2.   Problems with separation of individual process effluents within
         a plant complex
    3.   Plant size
    U.   Plant age
    5.   Effect of raw material variations
    6.   Existence,  "type  and  efficiency  of  air  pollution   control
         equipment
    7.   Land area available for waste water containment utilization  of
         wastes
    8.   Waste load characteristics
    9.   Treatability of wastes
    10.  Effect of rainfall - evaporation discrepancies


After completing the majority of the  twenty-five   (25)  separate  plant
visits  it  became  clear  that  only a small number of the above listed
items had real overall meaning for  categorization.   All  items  effect
plant  effluent  conditions  and  quantities.   However, they do not all
necessarily contribute to the categorization of  processes.   The  final
factors used to establish the categorization were:

    1.   Natural industry division
    2.   Waste load characteristics
    3.   Treatability of waste streams either by inter
         process reuse cr treatment technology

The application of these listed criteria resulted in  the  establishment
of  5  subcategories  for  the  industry.   These  together  with  their
component processes are listed below:
A. PHOSPHATE SUECATEGORY
    1.   PHOSPHATE ROCK GRINDING
    2.   WET PROCESS PHOSPHORIC ACID
    3.   PHOSPHORIC ACIC CONCENTRATION
    4.   PHOSPHORIC ACIE CLARIFICATION
    5.   NORMAL SUPERFHCSPHATE
    6.   TRIPLE SUPERIHCSPHATE
    7.   AMMONIUM PHOSPHATES
         SULFURIC ACID


                                     61

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B.  AMMONIA SUECATEGORY
C.  UREA SUBCATEGORY
D.  AMMONIUM NITRATE SUECATEGORY
E.  NITRIC ACID SUECATEGCRY

IndustrY_Division

The fertilizer industry is composed of multi-product plants.   with  few
exceptions  a phosphate complex does not include nitrogen type processes
(ammonia,  urea,  ammonium  nitrate  and  nitric  acid) .   This  natural
separation  of  the  industry  by  the  industry  coupled with the ether
following factors indicates that phosphate fertilizer  chemicals  should
constitute a separate category from nitrogen fertilizer chemicals.
                           2f Individual Process Effluent Within a Plant
Complex

A somewhat surprising fact brought to light in the study was the lack of
information available on specific process effluents  within  a  complex.
Fertilizer  complexes  are  generally  not  physically  designed to keep
individual process streams separate.   The  reasons  for  this  include:
there  previously  was no reason to do so; simplification of underground
sewer systems meant joint sewers and the practice of using effluent from
one process as a liquid in another process.

This rationale is appropriate for phosphate fertilizer complexes, mainly
because of the similar treatment  technologies  involved.   However,  at
nitrogen  fertilizer  complexes  inadequate treatment of pollutants will
frequently result if  the  process  waste  waters  from  each  component
chemical are not dealt with separately.

Plant Size

There  is  a  wide  range  of  plant  sizes  for  most  chemicals in the
fertilizer industry.  However, plant size will not  affect  waste  water
characteristics or treatability.

Pi an t_ Age

There  is  also  a  wide range of plant ages in the fertilizer industry.
This should not affect waste water characteristics  or  treatability  to
the degree where any additional subcategcrization is required.

Ef f ect, of Raw Material Variations

Variations  in  the raw material will affect waste water characteristics
in operations involving phosphate rock and the resultant phosphoric acid
or phosphate.  However, the effluent  limitations  in  such   cases  take
these variations into account.  Another problem is that these variations
are  unpredictable  and  difficult  to monitor, making subcategorization
based upon this topic impracticable.

                              _.of Air Pcllutioni-rCgntrol_E^uipjnent

-------
A major source of process waste water is from air scrubbers employed  at
all   plants.   The  treatment  technologies  proposed  are  practicable
regardless of the type cr efficiency of air pollution  control  devices,
and subcategorization is not warranted.

Land Area Ayailable_fcr Waste Water Containment

Confinement  of  process  waste  water  in  large  ponds  is universally
practiced at phosphate fertilizer plants.  These  ponds  range  in  size
from  65  to 570 hectares (160 to 1400 acres).   However, extremely large
ponds are not necessary to achieve the degree of treatment necessary  to
recycle  the process waste water.  The principal point is that the ponds
now exist and need not be expanded.   Use  of  biological  treatment  of
ammonia  and  nitrates in nitrogen fertilizer plants would require space
for treatment ponds.  If  land  availability  is  a  problem,  alternate
methods of ammonia and nitrate removal are available.

Waste Load_characteristics

The  phosphate  and  nitrogen  segments  of the fertilizer industry have
different waste water characterics.  For instance  a  phosphate  complex
effleunt  would  be  acidic due to phosphoric,  sulfuric, or nitric acids
used in the process.  A nitrogen fertilizer complex would  generally  be
alkaline  due  to  amnronia.   Phosphates and fluorides will be present in
the waste waters from a phosphate complex,  nitrogen  compounds  from  a
nitrogen  fertilizer  complex.  Within a nitrogen fertilizer complex the
different chemicals will  involve  different  forms  of  nitrogen.   For
instance, ammonia will naturally result from ammonia synthesis.  Ammonia
and  nitrates will result from ammonium nitrate production.  Ammonia and
organic nitrogen will result  from  urea  synthesis.   Such  differences
warrant subcategorizaticn of these latter chemicals.

Treatability of Wastes

This  is  the  principal  factor  used in determining subcategorization.
Production  of  all  phosphate  fertilizer  chemicals  requires  similar
treatment   methods   (i.e.    neutralization,  lime  precipitation,  and
settling).  The only need for a discharge is during periods of excessive
rainfall.  No process waste water is  even  generated  in  manufacturing
nitric  acid.   On the ether hand urea, ammonium nitrate and ammonia can
each require a different treatment technique to achieve best practicable
and best available technologies.

Ejffe.ct_of Rainfall^r Evaporation^ Discrepancies

Because of the almost universal use of ponds in the phosphate fertilizer
subcategory lengthy periods  where rainfall exceeds  evaporation  and/or
periods   of   rainfall   of  abnormally  high-intensity  necessitate  a
discharge.  Rather than create a separate subcategory, this  problem  is
better  handled  as a factor by which the standards can be varied, since
for any given month rainfall could exceed evaporation at any location.
                                     63

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                               SECTION V
                         WASTE_CHARACTEFIZATION


General

The intent of this section is to describe and identify the  water  usage
and waste water flews in each individual process.  Each type water usage
and   effluent   is  discussed  separately  and  includes  a  tabulation
indicating ranges  of  flow  and  contaminant  concentrations  for  each
process.   Flow  figures  are presented en a per kkg of product basis to
permit ready calculation of  flow  for  any  specific  production  rate.
Water  flow  information  is  also presented on individual process water
usage  flowsheets  tc  pictorially  indicate  the  various  water  flows
relative to the process equipment.

PhQSphate_Fertilizer_Industry

The  eight  process operations - sulfuric acid, phosphate rock grinding,
wet process phosphoric acid, phosphoric acid  concentration,  phosphoric
acid   clarification,   normal  superphosphate,  triple  superphosphate,
ammonium phosphates - in the phosphate fertilizer subcategory  have  the
following types of water usage and wastes.


    A.   Water Treatment Plant Effluent

         Includes raw water filtration and clarification,
         water softening, and water deionization.  All these
         operations serve only to condition the plant raw water
         to the degree necessary to allow its use for process
         water and stearr generation.

    E.   Closed Loop Coding Tower Slowdown

    C.   Boiler Blowdcwn

    D.   Contaminated Water

    E.   Process Water

    F.   Spills and Leaks

    G.   Non-Point Source Discharges
         These include surface waters from rain or snow that
         become contaminated.

    H.   Contaminated Water  (Gypsum Pond Water) Treatment

Each of the above listed types of water usage and wastes are  identified
as  to  flow  and contaminant content under separate headings.  Detailed
flow daigrams were previously presented in Figures 3 through 14.
                                     65

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A. Water^Treatment Pi ant _Ef fluent.

Basically only the sulfuric acid process has  a water  treatment  effluent:.
This  1300-1670  1/kkg   (310-UOO  gal/ton)  effluent    stream    consist
principal i.y  of  only the impurities removed  from the raw  water (:;u^v  ; -
carbonate ,  bicarbonates,  hydroxides,    silica,   etc.)    plus   miiio-
quantitie . of treatment  chemicals.

Th-  d<=qr ;e of water treatment of raw water required  is  depen lent  or  :•
steam pressure generated.  Generally medium-pressure  9.5-52  atm f1, Jr- 1c ~
csiq) sys :ems are used and do require  rather extensive  make-up   w t --•-r
'.reatment.  Hot lime-zeolite water treatment  is  the most commonly  ut-- \,

There  are  phosphate complexes particularly  alonq the Mississippi  Fiv  r
which use river water both for boiler make-up and  process  water.    Ir
th<=s =  plants it is necessary to treat the river water through  a set.-l-r
or clarification system  to remove the suspended  solids  present  in  the
river water before conventional water treatment,  is undertaken.   Effluent
limitations  for  water  treatment  plant  effluent   components  are  not
covered in this report.  They will be established at  a later date.

B. close_dT_Loop Cgoling^Tcwer^Blgwdgwn

The  cooling water requirements and normal  blowdown quantities  are  listed
in the  followinq  table.   Effluent  limits   with  respect  to  thermal
components  and  rust and bacteria inhibiting chemicals is coolina -^ower
blcwdown  or for once through cooling  water   are not  covered  in  this
report, but will be established at a  later date.
                                      66

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Q22iing Water

Process
Circulation Requirement
 1/kkg
          Discharge Requirement
           l/kkg           gal/ton
Sulfuric Acid  75000-83000
(per ton 100%)
H2S04

Rock Grinding     33-625
(per ton rock)

Phosphoric Acid    0-19000
(per ton P2O5)
              18000-20000   1670-2500
Phcs. A. Cone
(per ton P2O5)
    None
Phos. A. Clarifi- 690-3200
cation
 (per ton P.2O5)

Normal Super       None
 (per ton product)

Triple Super       None
 (per ton product)
Ammon Phos.
(per ton product)
    None
                  8-150
                  0-4500
None
                165-770
                  None
                  None
None
 33-625*


  0-19000*


  None


690-3200*



  None


  None


  None
                         UOO-600
                           8-150*
                           0-U500*
None
                         165-770*
                           None
                           None
None
     *  Non-contaminated	only temperature increase in
    discharge water.

Closed   loop  cooling  systems  function  with  forced  air  and  water
circulation to effect water cooling by evaporation.  Evaporation acts to
concentrate the natural  water  impurities  as  well  as  the  treatment
chemicals  required  to  inhibit  scale  growth, corrosion, and bacteria
growth.  Such cooling  systems  require  routine  blowdown  to  maintain
impurities at an acceptable operating level.  The blowdown quantity will
vary  form  plant  to  plant and is dependent upon overall cooling water
circulation system.

The quality of the cooling system blowdown will vary  with  the  make-up
water  impurities  and  inhibitor  chemicals  used.  The type of process
equipment being cooled normally has no bearing on the effluent  quality.
Cooling  is  by an indirect  (no process liquid contact) means.  The only
cooling water contamination from process liquids is  through  mechanical
leaks in heat exchanger equipment.  Such contamination does periodically
occur  and  continuous  monitoring  equipment  is  used  to  detect such
equipment failures.
                                    67

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The table below lists the normal range cf contaminants that may be found
in cooling water blowdcwn systems.

              Contaminant                    Concentration

                                                 mg/1

               Chrornate                          0-250
               Sulfate                         500-3000
               Chloride                         35-160
               Phosphate                        10-50
               Zinc                              0-30
               TDS                             500-10,000
               SS                                0-50
               Biocides                          0-100

Cooling tower blowdown can be treated separately or combined with  other
plant  effluents  for treatment.  The method to be employed is dependent
upon the chemical treatment method used and cost.   Those  plants  which
utilize  chromate  or  zinc  treatment  compounds  generally  treat  the
blowdown stream separately to minimize effluent treatment costs.

C.Boiler Blowdown

The only steam generation equipment in a phosphate  complex  other  than
possibly  auxiliary  package  boilers  is  in  the  sulfuric acid plant.
Medium pressure, 9.5-52 atm  (125-750 psig) , steam systems are  the  most
generally used.

Boiler   blowdown  quantities  are  normally  1300-1670  1/kkg   (310-400
gal/ton).  Typical contaminate concentration ranges  are  listed  below.
Separate  effluent  limitations for boiler blowdown with respect to both
thermal discharge and specific contaminants  are  not  covered  in  this
report.  They will be established at a later date.

        Contaminate                            Concentration

                                                    mg/1

        Phosphate                                   5-50
        Sulfite                                     0-100
        TDS                                       500-3500
        Zinc                                        0-10
        Alkanlinity                                50-700
        Hardness                                   50-500
        Silica  (Si02)                              25-80

D•Contaminated_Water JGypsumJPpnd Water)

Contaminated  water is used  to  supply essentially all  the water needs of
a  phosphate  fertilizer  complex.   The  majority  of  U.S.    phosphate
fertilizer  installations  impound  and  recirculate all water  which has
direct  contact with any of the  process gas or liquid streams.   This  im-
                                     6b

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pounded  and  reused  water  accumulates sizeable concentrations of many
cations and anions, but particularly F and P.   Concentrations  of  8500
mg/1   F  and in excess cf 5000 mg/1  P are not unusual.  Acidity of the
water also reaches extremely high levels (pH 1-2).    use  of  such  poor
quality  water  necessitates  that  the  process  equipment materials of
construction be compatible with the corrosive nature of the water.

Contaminated water is used in practically all process equipment  in  the
phosphate  subcategory  except  sulfuric  acid  manufacturing  and  rock
grinding.  The water requirements of such major water using equipment as
barometric condensers, gypsum sluicing,  gas  scrubbing  equipment,  and
heat  exchangers  are all supplied by contaminated water.  Each time the
water is  reused,  the  contaminate  level  is  increased.   while  this
contaminated  water  is  a  major process effluent, it is not discharged
from the complex.  The following  table  lists  ranges  of  contaminated
water usage for each process.
     Process
 Sulfuric Acid
     "Rock Grinding
 Wet Process Phosphoric Acid
 NPK Process-Nitric Acid
   Acidulation
 Phosphoric Acid concentra-
   tion
 Phosphoric Acid Clarifica-
   tion
 Normal Superphosphate
 Triple Superphosphate
 Ammonium Phosphate

E.Make-u£_Water
None
    None
16400-20800

1000-2300

2500-2600

 690-1040
 940-1040
 660-1040
5000-6500
     gal/ton

 None
     None
 3800-5000

 240-540

 550-570

 225-250
 225-250
 158-250
1200-1500
Make-up water in a phosphate complex is defined as fresh water untreated
except  for  suspended  solids removal.  Normally fresh water use to all
process units is  held  to  an  absolute  minimum.   Such  restraint  is
necessary  because  all  make-up  water  used  finds  its  way  into the
contaminated water system.  Excessive fresh  water  use  will  therefore
needlessly   increase   the  contaminated  water  inventory  beyond  the
containment capacity.   This  in  turn  means  contaminated  water  must
undergo  costly  treatment before discharge to natural drainage whenever
such discharge is permitted.

Normal ranges of make-up water use are listed  below  for  each  of  the
process units.  There is no discharge except into a process stream cr to
the contaminated water system.
                                     69

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                                  Make;up_Wat.er_Usage

                                  1/kkg
 Sulfuric Acid                63-83           15-20
 Rock Grinding                None            None
 Wet Process Phosphoric Acid  None            None
 Phosphoric Acid Concentration 0.8-1.6        0.2-O.U
 Phos Acid Clarification      None            None
 Normal Superphosphate        None            None
 Triple Superphosphate        None            None
 Ammonium Phosphates          None            None

F . Spills and Lgaks

Spills  and  leaks  in  most  phosphate  fertilizer  process  units  are
collected as part of the housekeeping procedure.  The collected material
is, where possible, re- introduced directly to the process  or  into  the
contaminated water system.  Spillage and leaks therefore do not normally
represent  a  direct  contamination  of plant effluent streams that flow
directly to natural drainage.
The primary origin of such discharges is dry fertilizer  material  which
dusts  over the general plant area and then dissolves in rain or meltinq
snow.  The magnitude cf this contaminant source is a  function  of  dust
containment,  housekeeping,  snow/rainfall quantities, and the design of
the general plant drainage facilities.  No meaningful data was  obtained
on this intermittant discharge stream.


H • Contaminated Water __ (G Y£§um_Pond_ Water] __ Treatment System

The  contaminated  water treatment system discharge effluent is the only
major discharge stream from a phosphoric acid  complex  ether  than  the
water  treatment  and blcwdown streams associated with the sulfuric acid
process.  Discharge from this system is kept to an absolute minimum  due
to  the treatment cost involved.  In fact, several complexes report that
they have not treated and discharged water for several years.  The  need
to  treat  and  discharge  water  has  been  previously  mentioned to be
dependent upon the contaminated water inventory.   As  a  result,  water
discharged from the treatment system is not done continuously throughout
the year.  Once the necessity for treatment occurs, however, the flow is
continuous  for  that period of time required to adjust the contaminated
water inventory.  Norirally, this period is 2-4 months per year,  but  is
primarily dependent upon the rainfall/evaporation ratio and occurence of
concentrated  rainfall  such as an abnormal rainy season or a hurricane.
Some phosphate fertilizer installations in the Western U.S.  perennially
have favorable rainfall/evaporation ratios and never have need to  treat
or   discharge  water.   The  quantity  of  water  discharged  from  the
contaminated water treatment  system  is  strictly  dependent  upon  the
design  of  the  treatment  system  and  has  no  direct  connection  to
                                     70

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production tonnage.  Contaminated water treatment systems generally have
capacities of 2085-UnO 1/min  (500-1000 gpm) .

The common treatment system is a two-stage liming process.   Three  main
contaminated  water  parameters,  namely  pH,  F,  and  P are addressed.
Reported ranges for these parameters after treatment are:

      pH                     6-9
      F                     15-40 mg/1
      P                     30-60 mg/1
                                     71

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Nitrogen_Ferti1izer_Industry

The four process operations - ammonia, urea,  ammonium  nitrate,  nitric
acid  -  in  the  nitrogen  fertilizer category, discharge the following
types of waste water.

A.Water treatment plant effluent   (includes  raw  water  filtration  and
clarification, water softening, and water deionization)

B.Closed loop cooling tcwer blowdown

C.Boiler blowdown

D.Compressor blowdown

E.Process condensate

F.Spills and leaks that are collected in pits or trenches

G.Non-point  source discharges that are "collected" due to rain or snow.
Detailed process flow diagrams have previously been presented in Fiaures
15 through 18.

A.Water Treatment Plant Effluent

The total effluent stream from a combined water  treatment  system  will
range  from  8   to 20  1/kkg  (2 to 5 gal/ton) of product with an ammonia
plant having the larger amount due tc the large  amounts  of  raw  water
used.   The  contaminants in this  effluent  are mainly  due to the initial
contaminants in the raw water and  therefore would  be  specific  to  the
area  and geographic conditions rather than the process plants  involved.
If the water treatment  plant effluent contains ammonia due to the use of
stripped,  process  condensate  as  process or  boiler   water   makeup
 (replacing  raw  water  makeup), then the ammonia - N discharge  allowance
is applicable.  Effluent limitations for specific components  (other than
ammonia - N) for treatment  plant  effluent are  not  covered  in  this
report.  They will be studied  at a later time.

B.Cooling^TQwer Slowdown

The  cooling  water  requirements  and expected blowdown requirements for
the four process plants in  the nitrogen fertilizer industry  are  listed
in the table below.
                                      72

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Ammonia
                                      Cooling Water

                   Circulation  Circulation  Slowdown       Slowdown
                   Requirement  Requirement  Requirement    Requirement
                   liter/1/kkg  gal/ton      liter/1/kkg    gal/ton

              104,000 tc    25,000 to     1,670 to      400 to 700
                   417,000       100,000       2,920

Urea           41,700 tc    10,000 to       375 to       90 to 350
                   167,000       40,000        1,470
Ammonia Nitrate    8,350 to     2,000 to        84 to       20 to 60
                    29,200        7,000          250

Nitric Acid   104,000 tc    25,000 to     1,250 to      300 to 600
                   146,000       35,000        2,500

In this closed loop cooling tower system, chemicals are added to inhibit
scale  formation,  corrosion  and  the  growth  of bacteria.  Due to the
nature of the make-up water, the inhibitor chemicals and the evaporation
water loss from the tcwer, a quantity of blowdown is required to prevent
excessive build up of chemicals and solids in  the  circualtion  system.
This  quantity  will  vary,  as  shown in the above table, from plant to
plant depending on the total circulation system.

The quality of this ccoling system blowdcwn will vary mostly with  make-
up  water  condition  and  inhibitor  chemicals  and will not be greatly
affected by the process plant associated with it.  Any leaks that  might
develop  in  process  or  machinery  exchangers should not significantly
affect the contaminant concentration of the cooling water.  The  largest
contaminant in the cooling water, that is neither intentionally added as
an  inhibitor  nor  ccmes  in  with  make-up,  is  ammonia.   Due to the
proximity of the cooling tower in relation to any of the  four  nitrogen
fertilizer  operations,  atmospheric  ammonia is readily absorbed in the
cooling water.

The table below represents some possible range of concentration for some
of the contaminants  that  might  be  contained  in  the  cooling  water
blowdown.

                     mg/1                mg/1

Chromate           0-250        Zinc     0-30
Ammonia            5-100        Oil     10-1,000
Sulfate          500-3,000      TDS    500-10,000
Chloride           0-40         MEA      0-10
Phosphate         10-50

This  blowdown  can be either treated by itself if necessary or combined
with other effluents for total treatment.  However,  it  is  recommended
that this stream be treated separately for chromate-zinc reduction since
this is main source of these contaminants  (Cr and Zn) to the total plant
                                     73

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effluent.   Effluent  limitations  for  noncontact cooling water are not
covered in this report.  They will be established at a later date.

C.Boiler Slowdown

The four nitrogen fertilizer processes will generate up to 6,000  kg  of
steam/kkg  (12,000  It  of  steam/ton)   of  product  depending  on  what
processes are at the plant site.   Ammonia will have  the  highest  steam
load  followed  by nitric acid, urea and ammonium nitrate.  The pressure
of the steam generated by and/or used in these plants  will  range  from
atmospheric up to 103 atm (1,500 psig).

Depending  on  the operating pressure of the steam system, the treatment
of  the  boiler  feed  water  will  vary   from   extensive,   including
deionization,  at  103  atm  (1,500  psig)  down  to  not much more than
filtration at atmospheric pressure.  Inhibitor chemicals are also  added
tc  boilers  to  prevent  corrosion  and  scale formation throughout the
system.

The combination of make-up water quality and the addition  of  inhibitor
chemicals necessitates blowdcwn periodically to remove contaminants from
the  boiler.    Based  on  the  actual  steam  generated  in  a  nitrogen
fertilizer complex, this blowdown quantity will range  from  42  to  145
1/kkg  (10 to 35 gal/ten) of product.

Typical  compositions  cf  contaminants in boiler blowdown from nitrogen
complex boilers are as fellows:
Phosphate
Sulfite
TDS
Zinc
  mg/1

  5-50
  0-100
500-3500
  0-10
Suspended Solids
Alkalinity
Hardness
Si02
mg/1

50-300
50-700
50-500
10-50
This effluent stream may be treated separately if necessary or  combined
with  the total effluent for treatment.  Effluent limitations for boiler
blowdown will be established at a later date.

D.compressor,Blowdown

This waste water effluent stream  has  been  separated  out  because  it
should  contain  the  largest  proportional  amount  of  oil and grease.
Primarily,  the  blowdcwn  containing  oil  will  come  from  interstage
cooling-separation in the reciprocating compressors operating on ammonia
synthesis  gas,  on  ammonia process air and on urea carbon dioxide.  If
these streams can be contained then oil separation equipment can be kept
to a minimum.

Due to the nature and expense  of  reciprocating  compressors  they  are
usually  replaced  by  centrifugal  compressors,  when the ammonia plant
                                     74

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capacity reaches 550 kkg/day (600  ton/day).    The  use  of  centrifugal
compressors  results  in  much  less  oil  and  grease  in  the blowdown
effluent.  The quantity of this blowdown will vary and can run up to 208
1/kkg (50 gal/ton)  of product.

E.Process Condensate

Process  condensate,  although  it  may  have  many   of   the   similar
contaminants,  will  be  handled separately for each of the four process
plants.

Ammonia Process Condensate

Process steam supplied tc the primary  reformer  is  in  excess  of  the
stoichiometric amount required for the process reactions and, therefore,
when  the  synthesis  gas  is  cooled either by heat recovery or cooling
water, a considerable amount of process condensate  is  generated.   The
quantity of this ccndensate will range from 1,500 to 2,500 kg/kkg (3,000
to 5,000 Ib/ton) of product.  The contaminants in this condensate may be
ammonia,  methanol,  some  organics  from  the  CO2  recovery system and
possibly some trace metals.  The ammonia discharged in this waste stream
can range from 1,200 - 1750 kg/1000 kkg  (2400 - 3500 lb/1000 ton).

Urea_Process Condensate^

Following the urea forming reactions the pressure is  reduced  to  allow
ammonia,  carbon  dioxide  and  ammonium  carbamate  to escape from urea
product.  Partial condensation of these flashed  gases  along  with  the
condensation  of water vapor from the urea concentration step results in
a condensate containing urea, ammonium  carbamate,  ammonia  and  carbon
dioxide.   The  quantity of this stream will range from 417 to 935 1/kkg
(100 to 225 gal/ton) cf product.  Ammonia discharge in this  stream  has
been  observed at the level of 9,000 kg/1000 kkg  (18,000 lb/1000 ton) of
urea product.  Urea discharge at the rate of 33,500 kg/1000 kkg   (67,000
lb/1000 ton) of urea product has also been cited.

Ammonium Nitrate Process^Cgndensate

The  nitric acid-ammonia reaction being highly exothermic causes a large
amount of water to be flashed off taking with it ammonia,  nitric  acid,
nitrates  and  some  nitrogen  dioxide.   If  climatic conditions or air
pollution regulations require that this stream be  condensed  then  this
contaminated condensate will range between 208 and 458 1/kkg (50 and 110
gal/ton)  of  product.  Ammonia discharges in the stream could be at the
levels of 150 kg/1000 kkg  (300 lb/1000 ton)  and ammonium nitrate at 7000
kg/1000 kkg  (14,000 lb/1000 ton) of ammonium nitrate product.

NitricmAcid^Process^Cgndensate

Using the ammonia  oxidation  process  for  production  of  55X  to  65%
strength acid there are no process condensate effluent streams.

F.Collected Spills and_Leaks

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In  all process plants there will be a small quantity of material either
spilled, during loading or transferring, or leaking from some pump  seal
or  bad valve.  When this material,  whether it be cooling water, process
condensate, carbon dioxide scrubbing  solution,  boiler  feed  water  or
anything  else,  gets  en  a hard surface where it can be collected in a
trench,  then  it  will  probably  have  to  be  treated  before   being
discharged.   The  quantity  of  this material is not dependent on plant
size, but more on the operating philosophy and housekeeping procedures.

G.Non^Point^pischarges

Rain or snow can be a  collection  medium  for  a  sizable  quantity  of
contaminants.   These  contaminants  may  be  air  borne ammonia that is
absorbed as the precipitation falls, or  it  may  be  urea  or  ammonium
nitrate prill dust that is lying on the ground around prill towers.  Dry
fertilizer  shipping  areas  may  also have urea and/or ammonium nitrate
that can be washed down by rain or snow.  Pipe sweat and drip  pots  are
another potential source of contaminants.
                                     76

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                               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

                     FHCSPHATE FERTILIZER INDUSTRY

Effluent  waste  water  from  the phosphate fertilizer processes must be
treated to reduce the following  primary  factors  and  contaminants  to
achievable  levels:  pH,  phosphorus,  fluorides,  ammonia and suspended
solids.

Secondary parameters which  should  be  monitored  but  do  not  warrant
establishment  of guidelines are:   total dissolved solids, temperature,
chemical oxygen demand  (COD), cadmium, total chromium,  zinc,  vanadium,
arsenic,  and  uranium.  The chief reason for not establishing standards
for the secondary parameters is that treatment of the primary parameters
will effect removal of these secondary parameters.   Another  reason  is
that insufficient data exists to establish effluent limitations.


RATIO^ALE^OR_^LECTING_IDENTIFIED_PARAMETERS

2H_-_Alkalinity__I_ Acidity

The  pH  of  an aqueous solution is defined as the negative logarithm of
the hydrogen ion concentration.  The pH scale ranges from 0 to 14 and  a
pH of 7 represents a neutral solution.  A pH of less than 7 indicates an
acidic solution.  A pH of greater than 7 indicates an alkaline solution.
The  presence  of large amounts of ammonia or acids in the waste streams
from this industry will affect the pH of the waste stream.
                                     77

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Phosphorus

Phosphorus is a plant nutrient, and essential  for  all  forms  of  plant
growth.   With  favorable  conditions, low phosphorus concentrations may
contribute to accelerated algae and vegetation growth  which,  in  turn,
reduces  the  dissolved oxygen content of the water.  This parameter may
appear in any process using either phosphoric acid or phosphate ore.

Fluorides

Soluble fluorides in discharged effluent waters are  considered  harmful
to  animal  and  plant  life.   This constituent is present in the waste
streams of this industry because of the fluoride  content  of  phosphate
ores.

Ammonia Nitrogen

Ammonia  nitrogen  is  a  contaminant  of  concern because of its varied
effects on plant life and humans.  The majority of this N is oxidized to
nitrites and nitrates.

Total_Chrgmium and Zinc

Cooling tower and boiler blowdowns are the sole source of these  metals.
Effluent  standards  for  constituents  in  noncontact cooling water and
boiler blowdown will be established at a later date.

Cadmium. Arsenic. Vanadium and Uranium
The amounts of cadmium, arsenic, vanadium and uranium present in Florida
and Western phosphate rocks were reviewed.  These elements  are  present
in  small  concentrations  in the rocks as shown by the following table.
In general,  these  elements  are  solubilized  by  the  phosphate  rock
acidulation  process  and  tend  to  be retained in the acid rather than
discarded with  the  gypsum  waste.   Only  cadmium  will  be  found  in
measureable  quantities  in  the  gypsum  pond, although small.  A toxic
limitation for -this pollutant will be established which will  cover  any
discharge of cadmium from the fertilizer categories.

                                 Phosphate Rock
                                    (mg/kg)
       Element               Flo£id§      Western
   Arsenic as AS03             5-30       6-140
   Cadmium as CdO                10         150
   Uranium as U308           100-200     50-100
   Vanadium as V203           10-200    400-4000
                                      78

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                      NITROGEN FERTILIZER INDUSTRY

                   SIGNIFICANT WASTE_VjATIB^PARAMETEgS


Effluent waste waters frcm a nitrogen fertilizer complex must be treated
to  maintain  the  following  primary  parameters within the recommended
guidelines:  ammonia nitrogen, organic nitrogen, nitrate  nitrogen,  pH,
and oil and grease.

Secondary  parameters  which  should be monitored but do not warrant the
setting of guidelines at this time are:  chemical oxygen  demand   (COD),
total  dissolved  solids   (TDS), suspended solids, total chromium, zinc,
iron, and nickel.  The chief reason for not establishing  standards  for
the  secondary  parameters  is  that treatment of the primary parameters
will effect removal of these secondary parameters.   Another  reason  is
that insufficient data exists to establish effluent limitations.

These  selections  are  supported by the knowledge that best practicable
control technology currently available does exist to control the  chosen
parameters  and  that improved technology is being developed and refined
to meet best  available  technology  economically  achievable  and  best
demonstrated technology.

Rationale^for Selecting^Identified_Parameters

Ammon ia _ Nit rog en

Ammonia nitrogen is the most prominent pollution parameter because it is
common  to all four process plants.  This contaminant is found mostly in
the process condensates but may  also  te  present  in  cooling  towers.
Although  some  ammonia  nitrogen  may  be  consumed  in  the  growth of
biological  organisms,  the  majority  would  probably  be  oxidized  to
nitrites and nitrates.

Nitrate,Nitrogen

Nitrate  nitrogen  is  found in contaminated process condensate from the
ammonium nitrate plant and spills and leaks from the nitric acid  plant.
Nitrate  nitrogen  in  waste waters can directly affect receiving waters
contributing to rapic algae growth.

Organic Nitrogen

Organic nitrogen contaminants in the waste waters consist mainly of urea
and lesser amounts of organic CO2 scrubbing solutions.   Such  compounds
can  supply  nutrient  nitrogen  for increased plant and algae growth in
receiving waters.

The organic scrubbing solution -  monethanolamine  (MEA)  -  can  add  a
slight BOD load to the effluent waste stream.
                                     79

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EH

While  nitrogen  fertilizer  plant effluents are normally consistent and
fall well within acceptable pH limits, abrupt changes must be avoided.

Oil & Grease

While some amounts  ccme  from  all  rotating  machinery,  reciprocating
compressors  for process air and synthesis gas in ammonia plants are the
greatest contributors tc oil contamination of the waste water.   Oil  in
the  receiving  waters can have deleterous effects on marine life, plant
life or plummaged water  fowl.   Oil  may  also  cause  taste  and  odor
problems.

Total^chrgmium and Zinc

Cooling tower and boiler blowdown are the major sources of these metals.
Effluent  standards  for  constituents in noncontact cooling water other
than ammonia and boiler blowdown will be established at a later date.

METHODS_OF_ANALYSIS

The methods of analysis to be used for  quantitative  determination  are
given  in  the  Feder.al_Rec|ister 40 CFR 130 for the following parameters
pertinent to this study:

                        alkalinity  (and acidity)
                            ammonia nitrogen
                                arsenic
                                cadmium
                                chromium
                                fluoride
                                hardness
                            nitrate nitrogen
                        nitrogen, total kjeldahl
                        oxygen demand, chemical
                               phosphorus
                             solids, total
                 suspended nonfilterable solids, total
                              temperature
                                  zinc

Organic nitrogen should be analyzed according to  Standard  Methods   for
t^e Examination of Water and Waste Water  (SMWW)  (ref W) method 215.

Oil  and grease should be determined by Methods for Chemical Ana.ly.sis of
Water and Wastes  (ref.X), page 217.

Vanadium should be determined by SMWW method 164.
                                     80

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                              SECTION VII
                    CONTROL AND TREATMENT TECHNOLOgY

The factors and contaminants in fertilizer process effluent streams have
for the most part been quite well identified and fairly well  known  for
many  years.   As a consequence considerable effort has been expended to
correct or  nrinimize  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-of-pipe 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 it.  Additional cr future corrective measures are for  the  most
part going to require capital expenditures which will do nothing towards
improving  operational economics and will, in fact, increase operational
costs.

With an appreciation of the above mentioned facts, it must be considered
that future expenditures  for  waste  water  treatment  should  be  well
documented  as  to  the  need, the degree of water quality required, and
assurance  that  the  specified  treatment  is  a  workable  and  viable
technology before the associated effluent limitation it is stipulated as
an  absolute requirement.  It was with these conditions in mind that the
following  criteria  were  established  as  a  basis  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  criterion  the  effort was made to factually
investigate overall treatment technologies  dealing  with  each  of  the
primary  factors  and contaminants listed in Section VI.  The results of
that investigation are covered separately  for  phosphate  and  nitrogen
fertilizers.
                    CONTROL AND TREATMENT TECHNOLOGY

                     PHOSPHATE FERTILIZER INDUSTRY


Process technology does exist for treatment and reduction of the primary
factors   and  contaminants  present  in  phosphate  fertilizer  process
effluent streams to the levels proposed.  These  treatment  technologies
are reviewed in the following paragraphs.
                                    81

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Sulfuric_Acid_Plant_EfJluent_Control

A  sulfuric  acid plant has no inherent water pollutants associated with
the actual production of acid.  An indispensible part  of  the  process,
however,  is heat remcval.  This heat removal is accomplished with steam
generating equipment and cooling towers.  Both of these cooling  methods
require  blowdown  and  subsequent  disposal  to  natural drainage.  The
amount and degree of impurities discharged  vary  widely  with  the  raw
water quality.

An  inherent  hazard cf any liquid handling process is the occurrence of
an occasional accidental break and operator error.  In a  sulfuric  acid
plant  the  sulfuric  acid cooling coils are most prone to an accidental
break.  On these occasions  the  cooling  tower  water  quickly  becomes
contaminated.  In turn, the normally acceptable practice is to take care
of  that  break  as  soon  as  it  is discovered and protect the natural
drainage waters.

Process Description

The facilities are relatively simple.  It involves the installation of a
reliable pH or conductivity continuous  monitoring  unit  on  the  plant
effluent  stream  (preferably  the combined plant effluent stream but at
least on the cooling tower blowdown).  A second part of the system is  a
retaining  area  through which non-contaminated effluent normally flows.
This retaining area can be any reasonable size but should be capable  of
retaining  a  minimum  of  24 hours of the normal plant effluent stream.
The discharge point from the retaining area requires a means of positive
cut-off, preferably a concrete abutment fitted with a  valve.   A  final
part  of  the  system  is somewhat optional.  For example, the retaining
area  could   be   provided   with   lime   treatment   facilities   for
neutralization.   In  addition equipment for transfering this acid water
from the retaining area to a contaminated water holding or recirculating
system could also be provided.  Plants 002 and 009 provide such  systems
to control process leaks.

The  procedure is that an acid break is detected by the water monitoring
instrument, located at the inlet of the cooling  tower,  and  causes  an
audible  alarm  to  be  sounded.   It  is  preferable  to  also have the
instrument automatically activate the positive cutoff at  the  discharge
of the retaining area although this can be done manually.  Activation of
this  system in turn necessitates a plant shutdown to locate the failure
and initiate repairs.  The now contaminated water in the retaining  area
must  then  be either neutralized in the pond or moved to a contaminated
water storage area where it can  be  stored  or  neutralized  through  a
central treatment system.

Figure  19 depicts a sketch of the suggested treatment facilities.  Such
a system provides continuous protection of natural  drainage  waters  as
well  as  means  to  correct  a  process failure.  The primary factor to
control is pH.  Sufficient  neutralization  to  raise  the  contaminated
water pH to 6 is required.  Neutralization is preferably by use of lime.
Lime  serves  not only to neutralize the hydrogen ion concentration  (low
                                     82

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pH)  but also removes sulfate   (SO4)  as  an  insoluble  calcium  sulfate
according to the following reaction:
   H2SOU +     CaO +        H20 - ^.CaSO4 .2HO

     Sulfuric      Lime       Water          Calcium Sulfate
        Acid
                                      84

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GYE§li!D_P2S^_lContajninated)	Water Treatrnent_

As  described  in  Section  V,  all  phosphate complex process effluents
(contaminated water)   are  collected  and  impounded.   The  impoundment
area,ranging  in size frcm 65 to 570 hectares (160 to 1400 acres) serves
two functions.  One function is as a storage area for  waste  by-product
gypsum  from  the phosphoric acid process.  The second is as an area for
atmospheric evaporative cooling of the contaminated water prior  to  its
reuse  back in the various process units.  This pond system functions in
a closed loop mode the majority of the time.  The time interval that  it
can  function  as  a no discharge closed loop system is dependent on the
quantity of rainfall it can accept before the 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 bodies.

Process Description

Contaminated  water  can  be  treated  effectively  for  control  of the
pollution parameters identified in section VI,  namely  pH,  phosphorus,
and  fluorides.  Treatment is by means of a "double liming" or two stage
lime neutralization procedure.

At least two stages of liming or neutralization are necessary to  effect
an  efficient  removal  cf  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 phosphoric acid
with some minor amounts cf soluble calcium phosphates.

The  first  treatment  stage provides sufficient neutralization to raise
the contaminated water containing up to 9000 mg/1 F and up to 6500  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 4.0,  the  fluorides  will  precipitate  principally  as
calcium fluoride  (CaF2) as shown by the following chemical equation.

 H2SiF6  +  3 CaO +    H20	>3 CaF2   +  2 H.20  + SiO2

Fluosilicic   Lime    Water     Calcium      Water    Silica
 Acid                           fluoride

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 5500 mg/1  P.   This  water  is
                                     85

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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
    Phosphoric      Lime
      Acid

     Ca(H2PO4)2 +    CaO
    Monocalcium     Lime
     Phosphate
                         H20	>Ca (H2P04) 2
                        Water  Monocalcium
                                Phosphate

                         H 20	> 2CaHP04
                        Water  Dicalcium
                               Phosphate
As before, this mixture is retained in a quiescent
CaHPOU and minor amounts of CaF2 to settle.
                                     2 H20
                                     Water
                                     Water

                                     2 H20
                                     Water
                                            area  to  allow  the
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  upcn  the  final  pH  level  and  quality  of   the
neutralization     facilities,     particulary     mixing    efficiency.
Neutralization to pH levels of 9-11 will reduce P values to  15-30  mg/1
or  less.   Figure  20  shows  a sketch of a well designed "double lime"
treatment facility.  Plants 002, 007, 008, 009, 010,  014  and  019  all
practice some degree cf liming.

Laboratory  and  plant  data  for  phosphorus  and  fluoride  removal is
presented below:
PH
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
 Phosphorus (mg/1)
laboratory   plant
        Fluoride (mg/1)
       laboratory plant
   500
   330
   200
   120
    20
     3
     1,
42
2*4
18
1*1
12
 8
 6
 3
 1.2
13
 8.5
 6.8
 5.8
 5.2
 4.8
 4.6
17
14
12.
12.
12,
12.
12,
12.
12.
12,
5
5
5
5
5
5
5
5
Although the starting concentrations are either arbitrary or specific to
that plant only, the data does show significant removal at high pH,
                                     86

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Up to this point, nothing has been mentioned about the pollutant ammonia
N in contaminated water.  Any phosphate complex containing  an  ammonium
phosphate  unit  will  probably  have  NH3-N  in  the contaminated water
system.  "Double lime" treatment alone will not reduce the  N  quantity,
although  at  high  pH  (greater  than 9.0), significant ammonia loss to
ambient air can occur.  To date there is no proven means of economically
removing NH3-N from aqueous solutions having such weak concentrations as
20-60 mg/1.  The best method to keep the NH3_-N contaminant level low  is
tc  prevent  its  entry  into  the main contaminated water system.  More
about the manner that this can be done is discussed  in  the  DAP  self-
contained process discussion.
                                     88

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Gypsum Pond_Water_Seepage Control

The  contaminated   (gypsum  pond)  water storage areas are surrounded by
dikes.  The base of these dikes  are  normally  natural  soil  from  the
immediate  surroundings.  As the need develops to increase the height of
the retaining dikes, gypsum is dug from inside the diked area and  added
to  the  top of the earthen base.  Dikes in Florida now extend to a 100-
120 ft. vertical height.  These combined earth/gypsum dikes tend to have
continual seepage of contaminated  water  through  them.   In  order  to
prevent  this  seepage  from  reaching  natural  drainage streams, it is
necessary to collect and re-impound it.

Seepage collection and re-impoundment  (Plant 002)  is  best  accomplished
by  construction  of a seepage collection ditch all around the perimeter
of the diked  area.   The  seepage  collection  ditch  needs  to  be  of
sufficient depth and size to not only collect contaminated water seepage
but  to  permit  collection  of seepage surface water from the immediate
outer perimeter of the seepage ditch.   This  is  best  accomplished  by
erection  of  a  small  secondary  dike  as  depicted on Figure 21.  The
secondary dike also serves as a back-up or reserve dike in the event  of
a failure of a major dike.

"The  design  of  the seepage ditch in respect to distance from the main
impounding dike and depth is a function of the geology of the  area  and
the  type  material  used  for  the dike.  In Florida, where the largest
number of phosphate complexes are located, the soil  condition  is  such
that little, if any, vertical water percolation occurs.  The soil at 4.5
   7.5  meter  (15-25  ft)  depths is unconsolidated ancient beach sands
which lay on top of  the  underlying  Hawthorne  matrix  deposit.   This
Hawthorne  matrix  deposit  is  basicly  a nonporous material made up of
impervious clay-sand-phosphate  pellet  mixture.   Surface  drainage  or
impounded  waters  percolate down to this Hawthorne layer.  Then, due to
the  nonporous  nature  of  Hawthorne  layer,  are  forced  to   migrate
horizontally  following the interface between the unconsolidated surface
soil and the Hawthorne layer.  Some data suggests that the  gypsum  pond
bottoms  tend  to  be self-sealing.  That is, compacted gypsum plus clay
fines and aluminum and iron silicates forced into  the  interstices  may
form an artificial "cement" like layer on the bottom of old gypsum ponds
which  is  both  acid  resistant  and  of  very  low  permeability.   In
conclusion, the design of seepage ditches must consider the area geology
and the phreatic water level of the impounding dike material to  achieve
an  effective seepage control system.  An installation of a pump station
at the low or collection point  of  the  seepage  ditch  completes  this
seepage  control  system.  The pumps serve to move the collected seepage
water back into the contaminated water  storage  area.   Normally  these
pumps  are  operated  only  a  few  hours  per  day but this is entirely
dependent upon the seepage and rainfall conditions.
                                    89

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Ammonium Phgspha-tegg If-Contained Process

It was mentioned in the "double lime"  treatment  description  that  the
best  means  of  reducing NH3-N from appearing in the contaminated water
system was to prevent its  entry  into  the  water.   NH_3-N  enters  the
contaminated  water principally through the ammonium phosphate plant gas
scrubber system.  A secondary entry point is by way of washdown or water
spillage into a surface drainage system.  Both of  these  process  waste
streams  can  be  segregated  along with the ammonium phosphate scrubber
waters from the gypsuir pcnd water system and can  be  either  introduced
back  into the process cr treated for ammonia removal prior to discharge
or inection into the gypsum pond.

One means of doing this is to adjust the  in-process  water  balance  to
permit  the absorption of these collected NH3-N containing waters (Plant
001).  The degree of water balance  adjustment  is  dependent  upon  the
quantity  of  water  in  the two identified streams.  Reduction of these
water streams to a  minimum  may  require  design  changes  to  maximize
scrubber water recirculation.

The  principal  means  of adjusting the ammonium phosphate process water
balance is to increase the concentration of  the  phosphoric  acid  feed
used  in the plant.  Normally 30-40% P205 phosphoric acid is required to
produce ammonium phosphates.  It  may  be  necessary  to  increase  this
concentration  to as high as 54% P.2O5.  This is dependent upon the water
quantity to be absorbed and the acid concentration required  to  produce
the  specific ammoniuir phosphate product.  Figure 22 is a sketch of this
procedure.
                                     91

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Wet Process Phosphoric Acid - Pond Water Dilution of Sulfuric Acid

General

The need to treat phosphate fertilizer  process  contaminated  water  is
almos-t  entirely  dependent  upon  the local rainfall/evaporation ratio.
This means that barring poor water management and  concentrated  periods
of heavy rainfall the complex fresh water use and pond water evaporation
are  essentially  in  balance.   Therefore,  any  means of making an in-
process change to significantly reduce fresh water  use  will  create  a
negative  water  balance.   in  turn,  this  will eliminate the need for
treatment of contaminated water and effect a no discharge condition.

There are two different methods to make an  in-process  phosphoric  acid
process  modification  to  permit  the  use  of  contaminated  water for
dilution of sulfuric acid.  Currently, the necessity of fresh water  for
this dilution step represents approximately 50% of the total fresh water
intake  to  a  phosphoric acid plant.  Not only does use of contaminated
water for sulfuric acid dilution eliminate (except for  extreme  weather
conditions)  water  effluent  from  a phosphate complex, but the overall
~P2Q5 recovery of the phosphoric acid complex is increased by that amount
of P2O5 in the contaminated water.

Both methods of accomplishing sulfuric acid dilution with pond water are
proprietary.  One method is considered a trade  secret.   The  other  is
protected  by patent.  Either process can be added to existent plants or
included in the design of a new facility.

The trade secret procedure involves two points.  One is  the  mechanical
means  by  which  the  dilution  is  made so as not to create a pluggage
problem.  The second involves redesign of the  phosphoric  acid  reactor
cooling  system to remove the heat load formerly removed by the sulfuric
acid dilution cooler  (Fig. 23) .

The patented process was developed and has  been  placed  in  commercial
operation  (44) .

It  involves  sulfuric acid dilution by a two-step procedure in a manner
radically different from  current  practice.    The  details  of  process
control,  vessel  design, and materials construction are all proprietary
information (Fig. 24).
                                     93

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                    CCNTPQL^AND TREATMENT TECHNOLOGY
                      NITROGEN FERTILIZER INDUSTRY

Proven technology exists and additional technology is  being  developed,
which  will  enable  the  nitrogen  fertilizer  manufacturer,   when used
properly, to attain the proposed effluent limitations.

Most  of  these  treatment  processes  are  reviewed  in  the  following
paragraphs of this Section.

Ammonia Stripping

This treatment method can be used on process condensate, boiler blowdown
or  cooling tower blowdcwn from ammonia plants, urea plants and ammonium
nitrate plants for the removal of ammonia from these streams.    However,
due  to  the large volumes of cooling tower blowdown and the presence of
scale forming contaminants in cooling tower and  boiler  blowdowns  this
method  is  best  suited  for  the  treatment  of  process condensate or
effluent from urea hydrolysis.

The stripping medium can be either air or steam depending on the desired
end use of the overhead vapors, the availability of  a  low  level  heat
sink and the local and national air pollution regulations.

1.Steam Stripping

There  are  a  number  cf  ammonia steam stripping units in operation in
nitrogen fertilizer plants in this country.   (Plants 006, 011, 015, 017,
020, and 024).  These range from  completely  integrated  process  units
producing  boiler  feed  water  quality  condensate  to  separate  units
treating  a  process  ccndensate   effluent   before   discharge.    The
concentration  of  ammonia in the condensate feed to the stripper varies
from 100 mg/1 to 1,300 ing/1 with the stripped effluent  ranging  from  5
mg/1  to  100  mg/1  giving reductions in some cases of better than 95%.
However, the best consistent results frcm an ammonia stream stripper  is
in the range of 20 to 30 mg/1 and this is highly dependent on the amount
of  steam  supplied and the pH of the contaminated feed condensate.  The
stripping of ammonia frcm water depends on how the ammonia exists in the
water.  In neutral solutions ammonia exists as NH^t~ while at  higher  pH
(11  to  12)  ammonia  exists  as  dissolved  NH3  gas.   The  following
equilibrium prevails:

NH4+    	> H+  + NH3  (g)

H+  * OH	•—^ H20

As the pH is increased towards 12.0 and as the temperature is  increased
the  reaction proceeds further to the right.  Therefore, if the stripped
condensate is to be discharged, consideration  to  artificially  raising
the pH with caustic should be made. If the condensate is to be reused as
boiler feed water then operation of the stripper at a higher temperature
(and pressure) would te the preferred design method.
                                     96

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The  design and operation of an efficient ammonia steam stripping system
is not simple  or  straight  forward.   Due  to  deviations  from  ideal
conditions,  the  stripping  column  requires considerably more transfer
units than theoretical tc produce a low residual ammonia  level  in  the
stripped  condensate   (bottoms).   One example of a separated condensate
stripping system which will produce a bottom condensate with a  residual
ammonia  concentration  of  25  to 30 mg/1 has a process condensate feed
rate of from 8.8 to 10.7 I/sec (140 to 170 gpm).   The  stripper  column
has  a  diameter  of 0.915 meters  (3 feet) and is 12.2 m. (40 ft.)  high.
The column is packed with stainless steel Pall Rings.

A second ammonia steam stripping system, operating on process condensate
from an ammonia plant, employs two columns operating in parallel with  a
total  contaminated  condensate  feed of 7.6 I/sec (120 gpm).  This unit
recently operated for a 22 day period producing  a  stripped  condensate
effluent  averaging  less  than  20 mg/1 ammonia while using slightly in
excess of .12 kg of steam/ liter (1 Ib. of steam/gallon)  of  condensate
fed.

A  third  steam  stripping  unit  operating satisfactorily is completely
integrated with an ammonia plant.  This stripping column  takes  process
condensate  and  steam  turbine  vacuum  condenser  condensate and steam
strips the ammonia to a level that is acceptable for boiler  feed  water
in  a  102 atm (1500 psia)  steam system.  The trayed stripping column is
1.37 m (4.5 ft.)  in diameter and about  12.2  m  (40  ft.)   high.   Some
recent data indicates that this unit is handling some 41 I/sec (700 gpm)
of total condensate input.   The effluent from the stripper has less than
5 mg/1 ammonia (Fig. 26).  A fourth amrrcnia steam stripping unit that is
completely  integrated  within  an  ammonia  plant  is  handling process
condensate and producing a stripped effluent that is acceptable for high
pressure boiler feed water.  This plant has been in operation  for  more
than two years.
                                     97

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COOLING
WATER IN
   OUT
               TO C02 SYSTEM-
               HOT CARBONATE SYSTEM-
               TO   ATMOSPHERE
STRIPPER
CONDENSER
                      AMMONIA
                      STRIPPER
                              \J
 REBOILER/
 STEAM
                   LEVEL
                   CONTROLLED
                   VESSEL-
                                                 CONDENSATE
                                     POSSIBLE CAUSTIC
                                     ADDITION
                                     IF DESIRED/REQUIRED
                                                 CONDENSATE
                                                 FEEDTANK
                                               TO COOLING TOWER ~
                                               TO SEWER ~
                                               TO BOILERS-
                                               TO RAW WATER
                                                 TREATMENT SYSTEM
                      FIGURE  25
            AMMONIA/CONDENSATE STRIPPING
                             98

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2. Air Stripping

A  considerable amount of work has been done on air stripping of ammonia
from waste water, but this has been in  the  field  of  municipal  waste
water  treatment.  Although this process does have some drawbacks,  it. is
worth mentioning because of its possible use in connection with nitrogen
fertilizer plant waste waters.  The major drawbacks of air stripping are
the very low efficiencies in cold weather and the deposition of  calcium
carbonate  scale  from  the  water  on  the  column packing or internals
resulting in plugging.

On the other hand, test data and installation performance to  date  show
that the ammonia in the effluent air will not exceed 10 mg/m3 (13 ppmv).
The  threshold  limit  fcr  odor of ammonia is 35 mg/m3 (46 ppmv).   With
this type of discharge there probably would not  be  any  air  pollution
problem.

As mentioned under steam stripping, temperature and pH have an effect on
the  stripping operation.  However, since temperature will be controlled
by the climatic conditions, pH must be  controlled  to  assure  complete
stripping.

Although  most  air  stripping  to date has been with contaminated waste
water with less than 60 mg/1 ammonia, the results obtained by using  the
proper  bed  depth,  the  proper  transfer medium and the proper surface
loading rate with good control of pH have given better than 90%  removal
of  the  ammonia.  The  resulting aqueous discharge can have less than 5
mg/1 ammonia  (Fig. 27).

Contrary to some reports, cooling towers are not  good  stripping  units
for ammonia contaminated waters.  Due to their construction and air flow
they  are  actually  abscrbers of air-bcrne ammonia with the result that
their blowdowns may contain up to 50 mg/1 of ammonia.
                                     100

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              FAN
AIR OUT
AIR IN
                              WATER IN   DISTRIBUTION
                                 I          BASIN
                    CATCH BASIN
                                             'TYPICAL FILL
                                             • BAFFLE (TYPICAL)
                                                        WATER OUT
                         FIGURE  27

             AMMONIA/CONDENSATE AIR STRIPPING
                    From Slechta And Gulp 1967
                              101

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3 • High Pressure Air/ Steam Spriggin
One engineering firm  (30) has proposed -the  use  of  the  process  steam
required  for  the  primary reformer or the process air required for the
secondary reformer as the stripping mediums for process condensate.    In
each  case,  the stripping would be performed at medium to high pressure
(pressure high enough tc get into the primary  or  secondary  reformer) .
This  would  require  the  process  condensate  to be boosted up to this
pressure, but if the condensate is then an acceptable boiler feed  water
make-up  there  would be very little energy lost since boiler feed water
would have to be boosted to the boiler pressure  anyway.   The  overhead
vapors,  whether steam/ammonia or air/ammonia, could be be injected into
the primary or secondary reformers, respectively, without  any  expected
problems.   Ammonia wculd be dissociated into its elements in either the
primary or secondary reformers and any  carbon  dioxide  that  might  be
stripped  from  the  condensate is present in the reformers anyway.   Any
organic compounds which strip over should also  be  dissociated  in  the
reformers.

If  the  stripped  condensate  is not to be used at these high pressures
then it can be flashed to lower  pressures  in  stages  to  release  any
additional ammonia.
                                     102

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Urea_HydrolYsis

This  effluent  waste  water  treatment  system  is  designed to process
condensate from urea plants by converting the urea through a  series  of
intermediate  products tack to ammonia and carbon dioxide.  This process
is carried out at temperatures above 100°C (212°F)  and  under  pressures
of up to 18 atm  (250 psig).  Following the conversion or hydrolysis, the
ammonia  and  carbon  dioxide  are stripped off and returned to the urea
process Plants 006 and 015.

One of the proprietary (40)  variations of this treatment is presented in
Fig. 28.  This flowsheet depicts a unit capable of  treating  4.2  I/sec
(66  gpm)   of  process effluent, containing 4000 mg/1 urea and 3000 mg/1
ammonia.  Aqueous discharge from this treatment unit  will  contain  100
mg/1  and  50 mg/1 of urea and ammonia respectively.  Steam requirements
for this unit are 2200 kg/hr (4840 Ib/hr)  of 19 atm (265 psig)  steam and
4000 kg/hr (8800 Ib/hr)  of 4 atm.  (44 psig)  steam.   It  is  understood
that  this  unit  will  be  offered commercially with a urea plant and a
guarantee will be given that the effluent will  not  contain  more  than
42.5  kg  (85  Ibs)   cf Org-N and 37.5 kg (75 Ibs)  of NH3-N per 1000 kkg
(1000 ton) of urea produced.

A second proprietary urea hydrolysis system is available  (41,  42)   This
treatment  unit has been installed in a urea plant in the spring of 1973
(Fig. 29).  Although cnly limited information is available to date,  the
new  unit  has  with some difficulty processed the urea plant condensate
giving very mixed, but in some cases, good results.   This  medium  size
installation is being modified from a control instrumentation standpoint
and  is  then expected to operate satisfactorily.  Although this unit is
not completely operative  yet,  it  is  expected  that,  with  continued
operating  experience and future design modifications, this process will
be commercially available with respectable guarantees regarding  ammonia
and urea levels in the effluent.

This  unit  consists  of  a  steam  heated vertical tower operated under
pressure,  to which the contaminated condensate is fed.  A  feed-effluent
heat  exchanger  is  included  to conserve energy.   The contaminants are
decomposed,  stripped cff and recovered in the urea synthesis section  of
the main plant.

A  third  type  of urea hydrolysis treatment system is in operation at a
fairly large urea plant.   The process was developed and installed by the
owner and therefore, very little detail  is  available.   Data  obtained
from  this  plant,  however,  does  show  that  the  hydrolysis  unit is
operating very well.
                                     103

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Biological Treatment^-_tjitrification and Denitrifjcation

This possible -treatment is based on the  reaction  of  ammonia  nitrogen
with  oxygen in an aerated pond or basin tc form nitrates via biological
oxidation.  The nitrates are in turn reacted in an anaerobic pond in the
presence of carbon to form elemental nitrogen.  Although there  has  not
been  any  significant  industrial  use  of  this combination, municipal
wastes have been treated in this manner for years.   Recently  more  and
more  investigations into this type of treatment for industrial use have
been made  (Fig. 30).

The first step-nitrification-takes place  in  the  presence  of  aerobic
bacteria  which convert the ammonia nitrogen to nitrates.  This reaction
is promoted by the degree of aeration and warm temperatures.  This  step
can  be carried out ir. a lagoon, pond or a trickling filter according to
the following equations:

 2NH3  +  302 	> 2NO2-  +  2H+  +  2H2O

 2NO2-  +  02 	>2NO3-

The denitrification step is an anaerobic process which occurs  when  the
biological micro-organisms cause the nitrates and available carbon to be
broken  down  into  nitrogen  gas and carbon dioxide.  A portion of this
CO2, in turn, is broken down  into  carbon  and  oxygen  to  supply  the
essential  elements tc sustain anaerobic biological growth.  The initial
breakdown of the nitrates requires that some amount of organic carbon be
present.  This can be  in  the  form  of  methanol  in  which  case  the
following overall reaction would occur:

 6N03-  «•  5CH30H-	> 3N2 + 5CO2 + 7H20 + 6OH~

This  reaction  must  be  carried  out  in  a pond, lagoon or tank under
anaerobic  (all dissolved oxygen must be  consumed)  conditions.   It  is
essential  that  complete  nitrification be obtained in a previous pond,
lagoon, etc. before the denitrification  process  starts;  this  usually
requires  longer retention time and lower load factors than are found in
conventional activated sludge plants.  Continuous  addition  of  organic
carbon   (e.g.  methancl)  and  inorganic  carbon   (e.g.  bicarbinate) to
accelerate the denitrification step rate  is  possible,  but  costs  are
elevated accordingly.

The  overall  oxidation-reduction  process  functions  best with initial
ammonia-nitrogen concentrations around 25 mg/1 but expected removals  of
90% can be achieved with carefully controlled operations.

However,  there are drawbacks, with by-products and side reactions which
can give rise to odorous compounds such as  hydrogen   sulfide  plus  the
ever present sensitivity to shock loads, e.g. ammonia  spills, etc.
                                     106

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Ion Exchange

Ion  exchange  is a unique effluent waste water treatment method in that
it not only removes the contaminants from the waste  water  but  it  can
also  produce  a useful end product.  An ion exchange system may consist
of a cation unit, an anicn unit or both, this depends on the  nature  of
the ions to be removed from the waste water.

1 . Cation/Anion ^ Separation Unit

The  first ion exchange system that will be covered is the integrated or
combined unit containing a cation resin  column  and  a  separate  anion
resin  column.   This unit can be used for the treatment of waste waters
containing both ammoniunr ions and nitrate ions (Fig. 31) .  The  ammonium
nitrate  contaminated  waste water first flows through a bed of strongly
acidic cation resin operating in the hydrogen form.   The  ammonium  ion
combines  with the cation while the H+ icn combines with the nitrate ion
to form nitric acid.
 NH4NOJI  +  R2!H+ - ^R2NH4  +  HNO3

The acidic waste water, minus the ammonium ion, then  passes  through  a
bed  of weakly basic anion resin where the nitrate ion combines with the
resin and water is fcrmed.

 HNO3  +  R2OH - > R2NC3  +  H2O

The effluent water from this second bed is low in ammonia  and  nitrates
and  can then be discharged or reused within the plant as make-up boiler
feed water, cooling tcwer make-up or recycled  back  to  the  raw  water
treatment unit.

Each  of  the ion exchange resins must be regenerated.  The cation resin
holding the ammonium ion can be regenerated using nitric  acid  to  form
ammonium  nitrate  solution  and  a  regenerated  strongly acidic cation
resin.  The anion resin holding the nitrate ion is regenerated  using  a
solution  of  ammonium  hydroxide.  This will form more ammonium nitrate
and a regenerated  weakly  basic  anion  resin.   The  major  difference
between  the incoming waste water and  the regenerate by-product is that
the latter has a 10% to 20% concentration of ammonium nitrate  versus  a
few  hundred  mg/1 in the raw waste water. This means that, depending nn
available fertilizer products on site, this by-product may be used as is
or it may be concentrated for sale.

A continuous unit, similar to that above, is  operating  at  Plant  022.
Information to date indicates that both the ammonium ion and the nitrate
ion  are  being removed to levels fcr ammonia-N of 12 to 50 mg/1 and for
nitrate -N of 6 to 40 mg/1 for a waste stream of one million gallons per
day.

2 • Selective Ion Ex change^f or _Ammonia Removal
                                    108

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Although this treatment process  has  not  been  industrially  installed
there  has  been  enough  testing  to  indicate that greater than 90% of
ammonia  nitrogen  can  be  removed  from   waste   streams   containing
approximately 25 mg/1 ammonia.  This  process (43)  is based on a natural
zeolite  ion exchange resin clinoptiloite.  The resin can be regenerated
with lime slurry yielding an alkaline aqueous ammonia solution, that can
be air stripped to reirove the ammonia.  The stripped slurry can then  be
recycled   to   regenerate   more  zeolite.   The  regeneration  of  the
clinoptilolite can be improved by the addition of sodium chloride to the
recirculated lime slurry.

Qil_Separation

Oil and  grease  in  waste  water  effluents  from  nitrogen  fertilizer
complexes  can  be  a  problem especially when large rotating machinery,
such as reciprocating compressors in small ammonia and urea  plants  are
in use.

Oil  and  grease can te removed from the waste water effluents to levels
below 25 mg/1 in properly designated A.P.I. Separators   (Fig.  32) .   To
assist  in  the  design  of  these separators, The A.P.I, in Washington,
D.C., has  published  "Manual  on  Disposal  of  Refinery  Wastes."  The
information  contained  in  this manual is applicable to nitrogen plants
effluent waste water.  Plants 003, 016  and  022  practice  oil  removal
treatment of their waste streams.  Oil and grease from many such sources
can  be  kept  out  of  the  effluent  by housekeeping techniques at the
source.  This can be accomplished by such containment  devices  as  drip
pans.

Ammonium Nitrate Condensate Reuse

Flashed  vapors  from  the neutralizer carry with them ammonia, ammonium
nitrate and some oxides of  nitrogen.   Partial  condensation  of  these
vapors  results  in  a  contaminated  condensate that requires treatment
before discharge.

One possible "treatment" method for this condensate stream is to collect
it and use it as the absorber feed in the associated nitric acid  plant.
Refer  to  Figure  33 for a process description of this treatment method.
Such  use  would  create  an  internal  recycle  of  streams   from  this
condensate  waste  in which both the airmonia and nitrate values would be
recovered, i.e. overall yields for both  the  ammonia  and  nitric  acid
units increased in terms of product ammonium nitrate.
                                     110

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                              SECTION VIII
               COST, ENERGY AND NON-WATER QUALITY ASPECT
General
A  detailed cost analysis of the various treatment methods pertaining to
the fertilizer industry have been  summarized  in  the  tables  of  this
section.

    The costs discussed are listed under subcategories as follows:

         (1)  Phosphate                               Table 2

         (2)  Ammonia, urea, ammonium                 Table 3
              nitrate and nitric acid

    All  investment  cost  figures  and  related  annual costs have been
    reported in August 1971 dollars.

    The treatment technologies summarized in some cases may be  utilized
    in series with each ether to meet more advance levels of control.

Water Effluent Treatment_Cost Tables

An  explanation of the water effluent treatment cost tables is set forth
to aid in understanding the magnitude of the figures set forth therein.

Investments

This includes the traditional expenditures, such as design; purchase  of
land  and  materials;  site  preparation; construction and installation;
plus those additional expenditures necessary or required  to  place  the
treatment  method  into  operation including expenditures for related or
needed solid waste  disposal.   Because  of  the  broad  general  scope,
methods and processes covered, nothing has been shown in the investments
for  losses  due  to  downtime;  i.e. production halts needed to install
pollution abatement equipment.  This is treated separately.

Interest on Money

This is more or less self-explanatory.  It is the cost of the money used
for investments on an annual basis.

Depreciation

There are numerous methods of  accounting  and  depreciating  equipment.
Because  of the nature cf the treatment technology and the way it may be
installed for utilization, all capital is depreciated over  a  ten  year
period by the straight line method.

              Maintenance costs
                                    113

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This  is  exclusive  of  energy and power which has been covered under a
heading of its own.  Costs here  include  materials,  insurance,  taxes,
solid waste disposal, operating labor and maintenance.

It is anticipated that iraintenance , as it is normally thought of in most
processes,  will be lower for the add on technology to achieve pollution
abatement.  Therefore, the costs are adjusted accordingly to  reflect  a
lower maintenance cost.

Energy_and Power Costs

Costs  for  energy and power include such items as electricity and steam
for pumps, agitators and evaporators/heat exchangers.

Ef f luent Qual i ty

The items covered are the expected parameters of the resulting  effluent
after  the  pollution abatement technology has been installed and placed
into operation.

The raw waste load flew has been given in liters per second and  gallons
per  minute.  Effluent level parameters are given in units of milligrams
per liter and kg/kkg cf product where appropriate.

Supplemental Data

This heading is for miscellaneous data  that  is  considered  useful  in
understanding or using the tables.  All items are identified as to their
nature or use.

                 Operation __ of .Treatment ^Methods
It  is  difficult  to  show  exactly  how  much  will  be involved in an
installation.  This is attributed to the fact that  no  two  plants  are
exactly  alike nor would they require the same amount of work, equipment
and land to be installed.  However, hypotheses have been made  in  order
to  permit  reasonable  estimations  as to the time and effort involved.
All plants are of 900 kkg/day (1000 tons/day) and  for  the  main  part,
considered  to  be existing plants.  The explanation for these items are
covered in order for Tables 2 and 3.

Since there is so much variation in time for certain types of work to be
done and equipment to be shipped, a total possible elapsed time will  be
given  under  each  treatment  method.   This  time  span  will include:
engineering, procurement and construction.

Also listed separately, as it applies, will be the amount of downtime to
make equipment tie-ins and length of time for start-up and  placing  the
unit(s) into operation.
                                    114

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Phosphate Subcategory (Table 2)

Sulfuric_Acid Effluent_Control

Total  elapsed time fcr engineering, procurement and construction should
be five months.

It should be possible tc arrange for this work to  be  accomplished  and
put into service with nc downtime to the plant operations.

No  start-up  is  required for this item.  It should be noted that as an
alternate the effluent may be discharged back to  a  retention  pond  or
gypsum pond until control has been restored.

Pond Waterjrreatment

The  elapsed  time  for  this  method  in  engineering,  procurement and
construction should be about fifteen to eighteen months.

There should be no need to shut any plant down to install or  make  tie-
ins of this method of treatment.

For  start-up and operations to be stabilized it will take approximately
one twenty-four hour day of continuous operation.

Gypsum Pond Water Seep_age_ContrQl

Since this is only a secondary dike arrangement it should not  interfere
with  plant operations both in construction and placing pump system into
service.

Construction time is considered the prime requirement  here.   The  work
around  a 80-100 hectare (200-250 acre) pond area should be accomplished
in ten weeks.  It is not anticipated that much  start-up  time  will  be
consumed  to  start  the  pumps,  so  time  for  this effort will not be
considered.
                                    115

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DAP Self Contained Process

This system is one that is considered to be existing  and  will  require
installation of an evaporator and related auxiliaries to concentrate the
feed acid stream.  This creates the negative water balance necessary, to
utilize the water from the local area.

Engineering,  procurement  and  construction time should be about twelve
months.

The system can be pre-ccnstructed ready for tie-in.  Only one eight-hour
day will be required to tie the unit in.   If  this  work  is  scheduled
around  a routine wash day in the phosphoric acid plant there will be no
downtime in production.

The start-up and operations should be done and the  unit  stabilized  in
approximately twenty-four to forty-eight hours.

Operational coverage for this unit should be no more than one half a man
per shift at an annual cost of approximately $UO,000 to $46,000.

Pondwater Use For Sulfuric Acid_Dilution	(Internal Method)

There  are  two  types  of  costs  listed here.  One is for adding to an
existing system and the ether is for a new plant installation.

The time required for a new plant  installation  is  not  involved  with
causing  a  plant  shutdown  for  tie-in;  therefore,  it  will  not  be
considered for engineering, procurement and construction.  Similarly  it
is not considered for start-up or operations.

Time  required  to  revise  an  existing plant is rather complicated and
complex.  The hard part of this job is installing  a  new  larger  flash
cooler system in place of the existing flash cooler system.

The  entire  elapsed  time for engineering, procurement and construction
should be about six tc eight months.

After considerable pre-fabrication has been completed,  the  plant  will
then  have  to  be shut down for three to four weeks of intensive change
out work on the equipirert.

This type work could be planned  and  executed  around  an  annual  turn
around  which would reduce the unproductive plant downtime to one to two
weeks.

The new system would be so similar to the  existing  system  that  there
should  be no additional time required for start-up and operation of the
modified system.

One other alternative for the installation would be  to  set  up  a  new
adjacent  structure  and  pre-construct  everything.  The plant downtime
could be cut to about four days tie-in time.
                                    117

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This again could be scheduled around an extensive  maintenance  program,
such  as  an  annual  turnaround.    By  so  doing there would be no lost
production from the plant.

Sulfuric_Acid_Diluticn_With_Pond^Water

This system can be engineered, procured and constructed in about fifteen
months.

It should be possible tc have the system prefabricated  and  constructed
so  very  little time will be required to make tie-ins.  The anticipated
tie-ins should be accomplished in eight to ten hours.

There will  be  no  start-up  time  involved  and  the  unit  should  be
stabilized in twenty-four hours of continuous operations.

It  is  believed  that  there  will  be no requirement or need for extra
operating personnel tc cover this method of treatment.

Nitrogen Fertilizer gubcategorjes  (Table - 3)

Ammonia/Condensate_Stri£Eing

Time for engineering, procurement and construction is eight months.

The system should be completely prefabricated and  constructed  so  that
plant shut-down time will be no more than three to four hours.

The  start-up  of  this  unit can be done very slowly and easily with no
more than twenty-four hours involved to stabilize the unit.  During this
time of stabilizing operations the rest of  the  plant  should  function
normally.

There  is  no known need to add more operating personnel to monitor this
unit.

Integrated Ammonia/Cgndensate Stripper Unit

The only  work  involved  here  is  installing  the  ammonia  condensate
stripper and piping it to the existing points for tie-in.

Engineering,  procurement  and  construction  time should be about eight
months to have the unit prefabricated and installed prior to tie-in.

The plant will be shut dcwn about six to ten hours to make tie-ins.

The start-up and operation should be very similar to that mentioned  for
ammonia/condensate  stripping.   There is no need for extra personnel to
give this unit coverage.

AmroiLia/Condensate Air
                                    118

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The easiest way to explain this system is to say that it is very similar
to a cooling tower.  To design, procure and construct such a unit can be
from twelve to fourteen months.

The tie-in to the plant will require about twelve to twenty- four hours.

Also there is no anticipated need for extra personnel  to  operate  this
unit.

Proprietary J40} _ Ur e a H ydr gl ys is

The design engineering, equipment procurement and construction should be
completed in approximately ten months.

The  plant  will  be shut down for equipment tie-ins for about twelve to
thirty-six hours.

This treatment method is a little more complex.  Therefore, it  is  more
involved to start up.  The unit is brought on line simultaneously as the
plant  start  up,  but  to  gain positive and stable control of the unit
could vary from twelve to thirty hours.

The unit in the early stages of start-up and operation could involve one
half to one man per shift.  When the unit becomes checked  out  and  the
operators  educated as to the operations of the unit the extra personnel
may be phased out.  This increased need may exist for four to six weeks.
The cost of extra coverage could vary from $4,400 to $12,500.
The unit is not considered complex and should take about ten  to  twelve
months for design, procurement and construction .

The tie-in of the unit should involve no more than six to eight hours of
down time for the plant .

When  the  unit is ready it will come on line when the plant is started.
Although the operator may not become very involved during the  start-up,
the unit will require increased monitoring until the operating and plant
personnel  are  familiar  with the unit and its limitations.  This could
involve one half to one man per shift for two to four weeks.  After  the
unit is stabilized the extra personnel may be phased out.

The increased operating surveilance could amount from $2,000 to $9,000.

Biological_Treatment __ JNitrif ication-Denitrif icationj_

Design,  procurement  and  construction time could be twelve to fourteen
months.

There is not enough start-up time involved to be  considered.   However,
there   will   be  monitoring  time  involved  during  the  normal  unit
                                     120

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operations.  It is estimated that about one quarter of  a  man  will  be
utilized at an approximate cost of $19,000 to $20,000.

Ammonium_Nitrate.Removal^by Ion Exchange

This  system  is  somewhat  more  complex  and involved than most of the
treatment methods discussed thus far.

To design, procure and construct the ion exchange system will take  from
fourteen to sixteen months.

The  start-up  and  operation  of this unit to date has experienced some
difficulty; mainly mechanical.  This  makes  it  somewhat  difficult  to
delineate the exact needs for operation of future installations.

It is anticipated that two persons per shift will be required to operate
the  unit.   The  cost  of  such labor will be approximately $145,000 to
$160,000 on an annual basis.

Qil/Grease_RemQval

The oil/grease removal systems  may  be  used  as1  single  units  or  in
series.  For this study they are used in series.

To  design,  procure  and construct such a unit would take approximately
eight months.

There is no  start-up  and  operation  time  involved  so  this  is  not
considered.   It  is  not  felt that these units will require additional
personnel to monitor or operate them.

Ammoniuni_Nitrate Effluent^ytilization

There is not much involved in this system.  It should take  about  eight
to ten months to design, procure and construct the modified system.

The plants should be down not more than two to three hours for the final
equipment tie-ins.

This  system is unique in its possible mode of operation.  It must be so
designed to enable the  ammonium  nitrate  and  nitric  acid  plants  to
operate independently of one another or in tandom with one another.  The
start-up  of  either  unit  should  require  a few minutes to set up and
initiate.  The switching from one unit to the other should be very  easy
and  quick to execute with no ill effect on the operations of the nitric
acid plant.

With the above in mind, no time is considered for start-up and operation
of the system.

There is no increase in requirements for operating labor.
                                    121

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Non-Water Quality Aspects of Treatment and_Control_TechnolQgies

Phosphate Fertilizers

The treatment and control technology proposed for use by  the  phosphate
fertilizer industry to meet the guidelines does not have any deleterious
non-water  quality aspects.  There are no air pollution, noise pollution
or identifiable  solid  waste  disposal  problems  associated  with  the
proposed waste water treatment methods.

Containment  of  contaminated  recirculated  (gypsum)   water must not be
accomplished with fluorine loses from  scrubbers  or  ponds.   Nor  must
containment  be  achieved by percolation to ground waters (or horizontal
subsurfact loses).

Nitrogen Fertilizers

There is one possible and one real air pollution  control  problem  that
may  exist  with  some  treatment methods.  At present, there are no air
pollution  regulations  on  ammonia.   When  considering   the   ammonia
stripping process using either air or steam, one must be concerned about
where  the  ammonia is going, most of the time into the air.  Tests have
shown that with air stripping, the off gas concentration  contains  less
than  10 mg/m3 (13 ppmv).  Since the threshold odor for ammonia is about
35 mg/m3  (46 ppmv) there would not be any  noticeable  odor  around  the
stripping  operations.   The  maximum  allowable  OSHA  concentration of
ammonia in air (on a time weighted basis) is 35 mg/m3  (46 ppmv).   Since
this  also is greater than the expected gas effluent and surrounding air
concentration, air/steam stripping of ammonia is not expected  to  cause
any air pollution problems.

Although the anaerobic  (without free oxygen) denitrification process has
been  used  for  years,  especially  in  the  municipal sewage treatment
plants, it is a process that tends to be more of an art than a  science.
The  operations  of  an  anaerobic treatment of denitrification pond can
take a great deal of care.  The internal reaction occurring can lead  to
the  formation  of  hydrogen sulfide if there is any sulfur present that
can create an odor  problem.   Therefore,  care  should  be  taken  when
considering  the  installation  of  a  denitrification  pond  as  to the
location of the plant site in relation to the  wind  direction  and  the
nearest town or inhabitants.
                                    122

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                               SECTION IX
             BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
                              "AVAILABLE

                       GUIDELINES AND LIMITATIONS


INTRODUCTION

The  effluent  limitations  which  must  be achieved by July 1,  1977 are
based on  the  degree  cf  effluent  reduction  attainable  through  the
application   of  the  best  practicable  control  technology  currently
available.  For the fertilizer 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  technology  currently  available  emphasizes
treatment  facilities  at  the  end  of a manufacturing process  but also
includes the control technology within the process itself.  Examples  of
in-process control techniques which are used within the industry are:
    *manufacturing  process  controls  *recycle  and alternative uses  of
    water  *recovery  an/cr  reuse  of  waste  water  constituents  *dry
    collection   of  airborne  solids  instead  of  (or  prior  to)   wet
    scrubbing.

Consideration was also given to:

    a.   The total cost of application of technology in relation to  the
         effluent   reduction   benefits   to   be  achieved  from  such
         application;

    b.   The size and age of equipment and facilities involved;

    c.   The process employed;

    d.   The engineering aspects of the application of various types  of
         control techniques;

    e.   Process changes;

    f.   Nonwater  quality  environmental   impact   (including    energy
         requirements) .

PROCESS WAgTE^WATER, GUIDELINES

Process   waste   water  is  defined  as  any  water  which  during  the
manufacturing process, comes into direct  contact  with  raw  materials,
intermediates,   products,  by-products,  or  gas  or  liquid  that  has
accumulated such constituents.  All values of guidelines and limitations
are expressed as consecutive 30 day averages in units  of  kilograms  of
                                    123

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parameter  per  metric  ton  and  pounds of parameter per 1000 pounds of
product produced except where they must be expressed as a concentration.
Maximum daily values are also presented.

Based upon the informaticn contained in Sections  III  through  VIII  of
this  report,  the  following  determinations were made on the degree of
effluent  reduction  attainable  with  the  application  of   the   best
practicable  control  technology  currently  available to the fertilizer
manufacturing industry.
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                         PHOSPHATE SUECATEGORY

                          GENERAL DESCRIPTION

The survey  (described  in  detail  under  Section  III)  of  designated
exemplary  phosphate  fertilizer  plants  was conducted to determine the
levels of contaminants being discharged  together  with  the  in-process
and/or  treatment  methods  used.   Results of this survey revealed that
isolated data from particular phosphate fertilizer plants is subject  to
many interpretations.  It is absolutely essential that the circumstances
and  conditions surrounding effluent data be known in detail by a person
knowledgeable in the industry, if meaningful guidelines and  limitations
are  to  be  established.  This point is of particular importance in the
phosphate fertilizer processes due to the only periodic  need  to  treat
and  discharge  process waste waters.  Such need is primarily a function
of climatic conditions ever which there is no human  control.   In  turn
this  practically  prohibits a guideline or limitation which relates the
allowable amounts of contaminant discharge to plant production.

Best Practicable Control Technology_Currentlv Available includes^

A.  Sulfuric Acid__Plant Effluent Control

    This  effluent  control  and  treatment  technology  is  in  current
    industrial  use.   The  technology  is  primarily  one of preventing
    contamination of natural drainage water  from  accidental  equipment
    break  or  operator  error.   It provides for a monitoring system to
    signal  that  an  emergency  exists  followed  by   facilities   for
    contaminated  water  isolation  and  subsequent  treatment.   A more
    detailed discussion of this technology is included in Section VII.

B.  Gypsum Pond (Contaminatedj	Water_Treatment

    The "double liming" treatment for gypsum pond  (contaminated)   water
    has  been  in common use for some 15 years.  There is little that is
    not known about the treatment capabilities and limitations.

C.  Ammonium PhQSphate_self-Contained^Process

    This  technology  serves  to  essentially  remove  ammonia  N  as  a
    contaminant in phosphate fertilizer process effluent.  The treatment
    is  an  in-process change which adjusts the process water balance to
    permit absorption of all process effluent  back  into  the  process.
    Principally,  this  is  accomplished  by  a  combination of reducing
    process effluent quantity to a minimum followed by  an  increase  in
    the  phosphoric feed acid concentration to a level which will permit
    reuse of the  effluent.   such  technology  may  require  additional
    phosphoric acid concentration facilities to maintain existing levels
    of  production  and  product  mix.   A  limited number of production
    plants are currently practicing this technology.

Even when the self-contained process is utilized, current practice is to
discharge leakage, spills, and washout wastes to the gypsum pond.    This
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is  considered  unsatisfactory.    To  meet  the best practicable control
technology currently  available,  segregation  and  treatment  of  these
additional  ammonia-N  waste  waters  will  be  necessary.   Appropriate
technology for such  ammonia  removal  has  already  been  discussed  in
Section  VII.   A  possible  alternative  not  discussed  in  detail  is
precipitation of the ainircnia as magnesium ammonium phosphate.

Proposed Effluent Limitatipns^Guidelines

The proposed effluent limitation representing  the  degree  of  effluent
reduction  attainable  through  the  application of the best practicable
control technology currently available tc the phosphate  subcategory  is
no  discharge  of process waste water pollutants to navigable waters.  A
discharge is allowed under the following conditions:
    1.   A  process  waste  water   impoundment   which   is   designed,
    constructed  and  operated so as to contain the precipation from the
    10 year, 24 hour rainfall event as established by the U.S.  National
    Weather  Service  fcr  the area in which such impoundment is located
    may discharge that 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.
    2.   During any calendar month in which  the  precipitation  exceeds
    the  evaporation  fcr  the  area  in  which  a  process  waste water
    impoundment is located, as established by the U.S. National  Weather
    Service   (or  as otherwise determined if no monthly evaporation data
    have been established by the National Weather Service) for the  area
    in  which  such  impoundment  there  may  be  discharged  from  such
    impoundment either a volume of process  waste  water  equal  to  the
    difference  between  the  precipitation and the evaporation for that
    month or a volume of process waste water  equal  to  the  difference
    between the mean precipitation that falls within the impoundment and
    the  mean  evaporation  for  that  month  as established by the U.S.
    National  Weather  Service  for  the  preceeding  10  year   period,
    whichever is greater.
    3.   Any process waste water discharged pursuant to subparagraph  (2)
    above shall not exceed each of the following requirements:

Parameter    Maximum daily     Maximum average of daily
             concentration     values for periods of discharge
                               covering 10 or more consecutive days
                mg/1              mg/1
phosphorus as(P)   20                10
fluoride as  (F)    30                15
nitrogen as  (N)    10                 5
total suspended
  nonfilterable
  solids           30                15
The pH of the water discharged shall be within
the range of  6.0 to 9.0 at all times.

Rationale for Best^Practicable Control Technology Currently  Available
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The  criteria  used  for  selection  of  the  treatment  technology  was
information  obtained  at  each listed exemplary plant through sampling;
inspection and review  of  plant  operations;  collection  of  validated
historical  effluent data; and direct discussions with responsible plant
operational personnel fcr positive definition of treatment  methods  and
analytical   procedures.    Additional  information  was  gathered  from
technical literature, direct contacts with experts and consultants,  and
discussions   with   vendors   of   treatment  equipment  and  services.
consideration  was  also  given  to  application  of  industry  transfer
technologies for specific contaminant treatment.

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  proposed effluent limitations for fluorine, phosphate,  nitrogen and
pH represent  an  unusual  effluent  situation  which  warrants  further
discussion.   Several  factors  need  to be recognized.  One is there is
only a periodic need for effluent treatment and  discharge.    This  need
essentially always results from excessive rainfall.

Another factor is the treatment limitations.  Particular reference is to
the  residual  P  and N levels after even the second lime neutralization
step.  The degree of P reduction is a function of pH level.   At a pH  of
6 the residual P in the treated water will range 30-60 mg/1.  Additional
neutralization  (third stage) to raise the treated water pH to 9-11 will
effect a P level reduction to the 15-25 mg/1 range.

Ammonia-N  also  is  a  particular  problem.   Even  though   the   best
practicable control technology currently available includes the ammonium
phosphate  self-contained  process,  there is still an N accumulation in
the contaminated gypsum pond water system.  The sources of  this  N  are
absorption  from  the  atmosphere  by contaminated water sprays in other
process units and also from a variety of non-point sources.   One complex
which has been utilizing the self-contained ammonia phosphate technology
has observed N  concentrations  in  the  range  of  25-66  mg/1  in  the
contaminated  gypsum  pond  water.  The N concentration is a function of
the discharge frequency with the higher  values  observed  during  those
periods  when  no  discharge  of  effluent is made from the contaminated
water treatment system.   Such  periods  are  normally  of  8-10  months
duration per year.  An ammonia N limitation is therefore still required.
The  primary  source  of  sulfate introduction to the effluent stream is
from the sulfuric acid cooling coils.  Traditionally,  these  have  been
cast  iron  coils  which  develop  small  cracks  plus  the  hundreds of
connection joints  which  are  subject  to  small  leaks  without  being
detectable.  New sulfuric acid cooling equipment such as stainless steel
heat exchangers with cathodic protection and teflon type heat exchangers
are   now   finding  increased  industry  acceptance.   Such  units  are
considered more reliable and less leak-prone than the  cast  iron  units
currently in universal use.
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                      NITgOGEN_FEgTILIZEg_INDySTRY

                          GENERAL^DESCRIPTION

The survey (described in detail under Section III)  of exemplary nitrogen
fertilizer  plants  was  conducted  as part of this project to determine
what level of contaminants was in the effluents from  these  plants  and
what  were  the  treatment methods in use to maintain these levels.  The
results of this survey revealed that none of these exemplary plants were
operating within the interim guidelines established  by  EPA.   However,
the  survey  also  revealed  that  there  were a number of errors in the
preliminary information used by the EPA in  establishing  these  interim
guidelines.  Therefore, a second review cf this survey data did indicate
that there were some process plants which could be considered exemplary.
Verifying  the  present  treatment  methods  in  use and those treatment
methods that are still being  developed,  the  following  technology  is
considered  to  be the best practicable and currently available which is
needed to meet the 1977 requirements:

Best Practicable_Controj._TechnolQgy^Currently Ayailable^Includeg:

A.  Ammonia Steam Stripping

    This treatment technology is in operation today in the plants  whose
    effluents  are  within  the newly proposed guidelines for ammonia-N.
    Although  each  nitrogen  fertilizer  complex  is  different,  steam
    stripping   of   ammonia   contaminated  waste  water  is  the  best
    practicable method of control.

B.  yrea_HYdrolysi s

    This type of technology is used in  various  forms  and  to  various
    degrees  in  urea  plants today to give an effluent waste water that
    will meet the newly proposed ammonia-N guidelines.  Although some of
    these hydrolysis units are company designed, commercial  units  that
    will meet the proposed effluent limitations are available.

C.  lon_

    Although this treatment technology has not been proven completely on
    a full scale  operation,  it  does  represent  the  best  technology
    currently available.  The ammonium nitrate by-product may have to be
    concentrated  and  sold  as is, rather than blending as is presently
    being tried.

D•  Qil_SeparatiQn

    Design technology for API oil separators has been  used  effectively
    for years and can now be applied to the nitrogen fertilizer  industry
    to help meet the guidelines.

         .Ef f luent_Limitations_Guidelines
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The  following  guidelines  are  recommended as the effluent waste water
limitations for the ammcnia, ammonium nitrate,  nitric  acid,  urea  and
subcategories.
Parameter



NH3-N

Organic N

N03-N

Oil & Grease
                                Ammonia

               kg/kkg of product   0.063
              (lb/1000 Ib)
               kg/kkg of product
              (lb/1000 Ib)
               kg/kkg of product
              (lb/1000 Ib)
               kg/kkg of product   0.0125
              (lb/1000 Ib)
Subcategory

  Urea    Ammonium Nitrate
0.0375
0.05*
0.0625
0.125*
0.05
              0.0625
*Effluent limitations fcr urea plants that prill their product.

The  above  limitations apply to the maximum average of daily values for
any period of 30 consecutive days.  The daily maximum average  is  twice
the  30 day maximum average.  pH shall be within the range of 6.0 to 9.0
at all times.
                                                   recommended  for  the
No discharge of process waste water pollutants is
nitric acid subcategory.

Rationale S Assumptions_for Selection of Technology

The  guidelines  used fcr selection of the treatment technology which is
required to meet the proposed 1977 effluent limitations have been  based
on   material   obtained  through  sampling,  data  taking,  information
gathering, and direct conversation with  plant  operating  personnel  at
each   and   every  plant  contacted  on  the  exemplary  plant  survey.
Additional information in  the  form  of  available  literature,  direct
contacts  and  vendor  contacts  was also considered.  Treatment methods
which are being successfully used in other industries were analyzed  for
their possible service tc the fertilizer industry.

The  proposed  limitation numbers are based on the best judgment of what
is reasonably obtainable after careful analysis of  time  weighted  data
over  periods  of up to two years.  These guideline numbers do represent
effluent levels that have been met by some of the exemplary  plants  and
can  be  conformed  with  by any of the nitrogen fertilizer plants which
will employ best practicable control technology currently available.

Ammonia steam stripping is one treatment method which is being  used  by
the fertilizer industry successfully at a number of locations.  However,
ammonia steam stripping is also in use in the petroleum industry.  Steam
stripping  of  ammonia has the drawbacks of what to do with the ammonia.
Under present circumstances, it is proposed that this ammonia be  vented
to  the  atmosphere either through the carbon dioxide stripper, reformer
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stack, or an off site boiler stack.  The ammonia  concentration  in  the
gases  from  these  stacks is not expected to be above 35 mg/m3 (46 ppmv)
which is the threshold odor limit for ammonia and, therefore, should not
present an air pollution problem.  The urea hydrolysis  units  that  are
operating  in  the  industry can produce an effluent which is acceptable
for the currently proposed guidelines.  Existing  units  have  had  some
mechanical  problems  but  these  problems  can  be solved with improved
engineering and additional  operating  experience.   Also  there  are  a
number of contracting companies who will offer this treatment method.

The  basic  ion  exchange  process  is  capable  of performing the waste
treatment  necessary  to  meet   1977   guidelines;   however,   further
development is necessary to completely automate and control the process.
Even  though  the  ammonium  nitrate  by-product  may  not be completely
acceptable to each manufacturing and retailing location, it can be  con-
centrated for a nominal expense and marketed at a reduced cost.

The petroleum industry for years has been using oil separators for waste
water  streams.   This  type  of treatment technology can very easily be
transferred from one industry to another.  The design  manual  published
by  the  American  Petroleum  Institute - Manual on Disposal of Refinery
HSSi§Sx. Volume on Liquid Wastes^ gives all necessary design  information
for an efficient oil separation device.

The pH of any effluent waste water stream should be between 6.0 and 9.0.
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                               SECTION X

                 BEST AVAILABLE TECHNQLOGY^ECQNOMICALLY
                               ACHIEVABLE

                              INTRODUCTION

The  effluent  limitations  which  must  be achieved by July 1, 1983 are
based on  the  degree  of  effluent  reduction  attainable  through  the
application  of  the  best available technology economically achievable.
For the fertilizer manufacturing industry, this level of technology  was
based  on  the  very best control and treatment technology employed by a
specific point source within the industrial category or subcategory,  or
where  it  is readily transferable from one industry process to another.
Best available technology economically achievable places equal  emphasis
upon in-process controls and control or treatment techniques employed at
the end of a production process.

Those plant processes and control technologies which at the pilot plant,
semi-works,   or  other  level,  have  demonstrated  both  technological
performances and economic viability at a level sufficient to  reasonably
justify  investing  in such facilities were also considered in assessing
best available technology economically achievable.  This  technology  is
the  highest  degree cf control technology that has been achieved or has
been demonstrated to be  capable  of  being  designed  for  plant  scale
operation  up  to  and  including  nc discharge of pollutants.  Although
economic factors are considered in this development, the costs for  this
level  of  control  reflect  the  top- of-the-line of current technology
subject to limitations imposed by economic and engineering  feasibiligy.
However,  best  available  technology  economically  achievable  may  be
characterized by some technical risk with  respect  to  performance  and
with  respect  to  certainty  of  costs.  Therefore, this technology may
necessitate some industrially sponsored development work  prior  to  its
application.

The  following factors were taken into consideration in determining best
available technology economically achievable:

    a.   The age of equipment and facilities involved;

    b.   The process employed;

    c.   The engineering aspects of the application of various types  of
         control techniques;

    d.   Process changes;

    e.   Cost  of  achieving  the  effluent  reduction  resulting   from
         application   of   best   available   technology   economically
         achievable

    f.   Non-water  quality  environmental  impact   (including   energy
         requirements).
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PROCESS WASTE WATER GUIDELINES

Process   waste  water  is  defined  as  any  water  which,   during  the
manufacturing process, comes into direct  contact  with  raw  materials,
intermediates,   products,  by-products,  or  gas  or  liquid  that  has
accumulated such constituents.

Based upon the information contained in Sections III through IX of  this
report, the following determinations were made on the degree of effluent
reduction  attainable with the application of the best available control
technology economically achievable in the various subcategories  of  the
fertilizer manufacturing industry.

                         PHOSPHATE_SUECATEGQRY

Best available technology economically achievable includes:

    Wet_Process PhQSp-horic_Acid_-_JPgnd Water Dilutionmof Sulfurjc Acid

    This technology serves to insure  a  negative  water  balance  in  a
    phosphate  fertilizer  complex.   That is, there will always be need
    for fresh water addition to the process units under  the  assumption
    that  reasonable  water  management  is  practiced.  With a negative
    balance, no discharge  is  required  except  under  extreme  weather
    conditions  in  which  the recirculating water containment volume is
    exceeded.

    The treatment involves an in-process change  in  the  procedure  for
    diluting  sulfuric  acid.  Two different methods have been developed
    to  circumvent  the  problems   of   equipment   pluggage   formerly
    experienced  when contaminated  (gypsum pond) water was used for such
    dilution.  As  previously  mentioned,  both  of  these  methods  are
    proprietary but are commercially available.

Propoged_Best_Ayailable Technology Economically Achievable

The  proposed  effluent  limitation  representing the degree of effluent
reduction obtainable by the application of the best available technology
economically  achievable  is  no  discharge  of  process   waste   water
pollutants  to  navigable waters.  A discharge is only allowed under the
following condition.   A  process  waste  water  impoundment,  which  is
designed,  constructed  and  operated so as to contain the precipitation
from the 25 year, 24 hour rainfall event  as  established  by  the  U.S.
National  Weather  Service  for  the  area  in which such impoundment is
located, may  discharge that volume of precipitation  that  falls  within
the  impoundment  in  excess  of that attributed to the 25 year, 24 hour
rainfall event, when such event occurs.
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    RATIONALE FOR BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE

The use of the best,  available  technology  economically  achievable  on
sulfuric  acid  dilution  in  a phosphoric acid plant is to a degree not
proven commercially in the U.S.  This is also true of both the described
processes.   There  is,  however,  sufficient   industrial   experience,
confidence,  and  warranty  available en one of the treatment methods to
justify its incorporation into the design of three large new units which
will come on stream in 1974.  The other  method  has  had  a  unit  very
similar to the patented method in commercial operation for approximately
two  years.   The unit new in operation is a more refined version of the
same process and has proven its ability  to  function  well  by  use  of
correct  construction  materials.   Both  methods  are  considered to be
technically proven and viable technologies.

The use of pond water for sulfuric acid  dilution  reduces  fresh  water
consumption  by  approximately  50* in a phosphoric acid plant.  It also
provides an attractive financial payout  on  phosphoric  acid  operating
efficiency  by  reclamation  of  water soluble PJ2OJ5 values in the gypsum
pond water.  It is also possible through better  reclamation  procedures
of  uncontaminated  steair  condensate streams to make the negative fresh
water balance even more negative.

Based upon the above  discussion  regarding  best  available  technology
economically  achievable,  it  is considered practical and economical to
establish a no discharge limitation on phosphate complex effluent.

NITROGEN FERTILIZER INDUSTRY

The  following  technology  is  considered  to  be  the  best  available
technology economically achievable:


A.  Ammonia steam stripping followed by either  high  flow  ammonia  air
    stripping   or   biological   nitrification-denitrification.    This
    combination can be designed to keep the ammonia nitrogen well within
    the 1983 guidelines.

B.  Improved continuous ion exchange followed by denitrification.   This
    treatment  system can provide the technology to maintain the nitrate
    nitrogen within the effluent guidelines.

C.  Advanced  urea  hydrolysis  followed  by  high  flow   ammonia   air
    stripping.   The  urea  hydrolysis  technology is fast improving and
    will be capable of meeting the proposed guidelines.

Proposed Ijest Ayailable_TechnQlQgy Econcmically^Achieyable

The following guidelines are recommended as  the  effluent  waste  water
limitations  from  the  ammonia,  nitric acid, urea and ammonium nitrate
subcategories:
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Parameter           Units

                                                     Ammoniuin Nitrate
NH3-N            kg/kkg of product 0.025     0.015       0.0075
                (lb/1000 Ib)
Organic N        kg/kkg of product -         0.025
                (lb/1000 Ib)                  0.0375*
N03-N            kg/kkg of product -          -          0.0125
                (lb/1000 Ib)
Oil 6 Grease     kg/kkg of product 0.0125
                (lb/1000 Ib)

* Effluent limitations for urea plants that  prill their product.
The above limitations apply to the maximum average of daily  values  for
any  period  of 30 consecutive days.  The daily maximum average is twice
the 30 day maximum average.  pH shall be within the range of 6.0 to 9.0

No discharge of process waste water pollutants is  recommended  for  the
nitric acid subcategcry.

Rationale gnd Assumptions for Select ign^of_Technology

Although  economics  cannot  be  over looked, there will be considerable
changes before 1983 which  will  alter  the  economic  analysis  of  any
treatment system proposed and therefore the selection of 1983 technology
will  lean  more towards the availability of processes than the detailed
economics.  The possibility of new improved technology  being  developed
between  now  and  1983  can  only enhance the owner -operators choice of
treatment methods capable of meeting these guidelines.

Much of the technology proposed is still in the development  stage  such
as  high  flow  air  and  steam  stripping,  continuous ion exchange and
advanced urea hydrolysis.  However, progress to date shows that much  of
the   remaining   work   deals   with  mechanical  improvement,  control
instrumentation and equipment modifications which should make  each  one
of these processes completely functional.
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                               SECTION XI

                    NEW SOURCE^PERFORMANCE^STANDARDS
                    AND PRETREATMENT~RECOMMENpATIQNS

                              INTRODUCTION

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  cf  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
tahn 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); and

    f.   Recovery of pollutants as by-products.

PROCESS WATER GUIDELINES

Phgsghate^Subcateggry

It is recommended that new source performance standards be identical  to
the 1983 limitations for all new phosphate fertilizer plant sources.

Nitrogen Fertilizer Industry
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General_ Discussion


In addition to the treatment technologies listed under the 1977 and 1983
technologies  the following process modifications and plant arrangements
may be considered.

Best Demonstrated^TechnclQgy jprocess Imprpyements)

A.  Integration of an ammonia process condensate steam stripping  column
    into  the  condensate-boiler  feed  water system of an ammonia plant
    with or without further  stripper  bottoms  treatment  depending  on
    boiler quality make-up needed.

E.  Building  of  adequate  sized  urea  and  ammonia  plants  so   that
    centrifugal rather than reciprocating compressors can be used,

C.  Designing in contaminated water collection systems  so  that  common
    contaminant   streams   can  be  segregated  and  treated  in  minor
    quantities for improved efficiencies and reduced treatment costs.

D.  Location of plant cooling tower  up  wind  of  the  prevailing  wind
    direction  to  minimize the chance of absorbing ammonia in the tower
    water.

E.  Design of a low velccity air flow prill tower for urea and  ammonium
    nitrate  to  minimize the dust loss.  This can reduce the yield loss
    around the prill tower from  35t  down  to  less  than  0.5%  with  a
    corresponding reduction in the raw waste load.

F.  Design for a lower pressure steam level, say 41.8 atm  (600 psig)  to
    62.2  atm  (900 psig), in an ammonia plant to make process condensate
    recovery easier and less costly.

G.  Install air cooled  condensers  and  exchangers  where  possible  to
    minimize cooling water circulation and subsequent blowdown.

Proposed New_Source Performance^Standards

Th,e  following  guidelines are recommended for new source effluent waste
water standards from the ammonia, urea, nitric  acid,  ammonium  nitrate
and subcategories:
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Parameter           SDiiS                  Subcategory

                                Ammonia      Urea    Ammonium Nitrate

NH3-N            kg/kkg of product 0.055     0.0325      0.05
                (lb/1000 Ib)
Organic-N        kg/kkg of product -         0.0375
                (lb/1000 Ib)                  0.0625*
NO3-N            kg/kkg of product -          -          0.025
                (lb/1000 Ib)
Oil & Grease     kg/kkg of product 0.0125
                (lb/1000 Ib)

* Effluent limitations for urea plants that  prill
their product.
The  above  limitations apply to the maximum average of daily values for
any period of 30 consecutive days.  The daily maximum average  is  twice
the  30 day maximum average.   pH shall be within the range of 6.0 to 9.0
at all times.

No discharge of process waste water pollutants is  recommended  for  the
nitric acid subcategory.

Rationale & Assumptigns_in_the DevelQBment of New Source
Performance Standards

One major problem in trying to treat waste water contaminants is that of
dealing  with  large  quantities  of  water with very dilute contaminant
concentrations.   Most  existing  plant  complexes  have  very   limited
facilities  for keeping different waste waters separated and, therefore,
any treatment system installed has to handle large amounts  of  effluent
waste  water.   The  construction  of  a  new  process  plant  and  more
noticeably  a  nitrogen  fertilizer  complex  allows  the  design  of  a
contaminated   water   separation/   collection  system  to  allow  more
efficient, less costly treatment of contaminants.  More improved use  of
plant  water  including  recycling  should  also  aid  in treating waste
effluents.

Best available technology  currently  available  is  applicable  to  new
sources as it becomes available on a commercial basis; however, all best
practicable  control  technology currently available can be up-graded to
treat "concentrated/separated" waste water effluents from new plants  to
meet  the  New  Source  Performance  Standards.  Therefore some effluent
limitations for new sources are less stringent than those for  the  1983
standards  because the technology is still being refined.  Of particular
importance is the  placement  of  cooling  towers  in  relation  to  the
ammonia,  air  emissions  sources.   Downwind  absorption  of ammonia by
recycled cooling water can significantly contribute  to  the  raw  waste
load.   New  plants  have the freedom of plant arrangement that existing
plants do not.  Furthermore,  through good engineering design, new plants
should be able to eliminate the problem at the source by minimizing  air
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leaks.  Since much of the 1983 -technology is not commercially available,
the  above  limitations  represent  engineeringing  judgment  as to what
improvements  can  be  implemented  beyond  best   practicable   control
technology currently available.

PretreatJDgnt Reguirements for'New Sources

The  type  of  waste  water  effluent that is discharged from a nitrogen
fertilizer complex contains compounds,  such  as  ammonia  nitrogen  and
nitrate  nitrogen, that would pass through a typical activated sludge or
trickling filter waste water plant and therefore this waste water at its
normal concentration levels  would  not  be  amenable  to  treatment  by
conventional  biological  treatment  processes.  No discharge of process
waste water pollutants from new  sources  to  publicly  cwned  treatment
works  is  recommended  for the phosphate and nitric acid subcategories.
For the remaining sutcategories pretreatment and treatment  provided  by
the  publicly  owned  treatment  works  must  sum  to equal the effluent
limitations for discharge to navigable  waters  for  new  sources  if  a
discharge to publicly owned treatment works is to be allowed.
                                    138

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                              SECTION XII
                            ACKNOWLEDGMENTS

    This  study  has  been  made  possible  by  the following companies,
institutions,  associations, laboratories, agencies, and  persons.   They
are  to  be  commended  for  their  help,  assistance and cooperation in
providing information:
1.  Borden Chemical Company, Piney Point, Florida
2.  Royser Fertilizer company. Mulberry, Florida
3.  American Cyanamid, Erewster, Florida
4.  Agrico Chemical Company, South Pierce, Florida
5.  W. R. Grace, Mulberry, Florida
6.  Gardinier (USPP), East Tampa, Florida
7.  Apple River Chemicals, East Dubuque, Illinois
8.  Cooperative Farm Chemicals Association, Lawrence, Kansas
9.  Phillips,  Hoag, Nebraska
10. Cominco-American Hcag, Nebraska
11. Chevron Corporation, Ft. Madison, Iowa
12. North Carolina Nitrogen complex, Tunis, North Carolina
13. Central Farmers, Incorporated, Tyner, Tennessee
14. J. R. Simplot, Pocatello, Idaho
15. Valley Nitrogen, Helm, California
16. Vistron Corporation, Lima, Ohio
17. Terra Chemicals International, Inc., Sioux City, Iowa
18. National Phosphates/ Taft, Louisiana
19. Triad Chemical, Dcnaldsonville, Louisiana
20. Mississippi Chemical Corporation, Yazoo City, Mississippi
21. Mississippi Chemical Corporation, Pascagoula, Mississippi
22. Socal, Pascagoula, Mississippi
23. Freeport Chemical company, Convent, Louisiana
24. St. Paul Ammonia Products, St. Paul, Minnesota
25. Farmland Industries, Fort Dodge, Iowa
26. Thornton Labratory, Tampa, Florida
27. Serco Laboratory, Minneapolis, Minnesota
28. Harris Laboratories, Lincoln, Nebraska
29. Stewart Laboratory, Knoxville, Tennessee
30. James Engineering, Armon, New York
31. Mr. A. L.  West, Lakeland, Florida
32. Dr. James A. Taylor, Lakeland, Florida
33. Mr. W. A.  Lutz, fceston, Connecticut
34. The Fertilizer Institute
35. The Environmental committee, The Fertilizer Institute
36  Florida Phosphate Chemists Association
37. Davy Powergas, Inc., P.O. Box 2436, Lakeland, Florida
38. stamicarbon N.V, Dutch State Mines, Geleen, Netherlands
39. IVO MAROVIC, Consultant, New York, New York
40. Technip, Inc., 437 Wadison Avenue, New York, New York
41. Battelle Northwest, Richland Washington
42. United States  Steel  Agricultural  Chemicals  corporation,  Bartow,
    Florida.
    Those  persons,  not  already  mentioned,  who  participated  in the
    working group/steering committee in order to coordinate the internal
    EPA review are:
                                    139

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43.  Mr.  Walter J.  Hunt, Effluent Guidelines Division, EPA.
44.  Mr.  Elwood E.  Martin, Effluent Guidelines Division, EPA.
45.  Mr.  Harry Trask, Office of Solid Waste Management Program, EPA.
46.  Mr.  John Savage, Office of Planning and Evaluation.
47.  Mr.  Srini Vasan, Region V, EPA.
48.  Dr.  Edmond Lomasney, Region VI, EPA,
49.  Mr.  Paul DesRosiers, Office of Research and Monitoring, EPA.
50.  Dr.  Murray Strier, Office of Permit Programs, EPA.
51.  Mr.  Ray McDevitt, Office of General counsel, EPA.
52.  Mr.  Ray Insinger, Office of Planning and Evaluation, EPA.
53.  Dr.  Robert R.  Swank, Jr., Office of Research and Development, NERC -
    Corvallis, Athens, Georgia.
54.  Mr.  Michael W. Kosakowski, Effluent Guidelines Division, EPA.

Special appreciation is given to the secretarial staff,  especially  Ms.
Sharon  Ashe,  Ms. Kay Starr, Ms. Chris Miller and Ms. Nancy Zrubek, for
typing  and  revision  of   this   and   the   accompanying   documents.
Appreciation  is also given to Ms. Kit Krickenberger who coordinated the
secretarial staff assignments.
                                     140

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                                    SECTION XIII
                                     REFERENCES


      A-   iHP-iStSSi?-  Fertilizer  and  Phosphate  Mining  Industries  -   Water
          P.2lil*tion and Control

          prepared by Battelle Memorial Institute Richland, Washington for the
          Environmental Protection Agency,  Grant No.  12020FPD,  September 1971,
          U.S.  Government Printing Office,  Washington,  D.C., 20402.
»
      B-   Advanced Wastewat6r_Treatment

          by Russell L.  Gulp  and  Gordon   L.  Gulp,  Van  Nostrand  Runhold,
          Environmental   Engineering   Series,   Copyright   1971  by  Litton
          Educational Publishing, Inc., New York, Library of Congress, Catalog
          Card Number 78-147192.

      C.   Ammonia Removal inja^Physical-Chemical_Wastewater Treatment_Process

          by Robert A.  Barnes, Peter F. Atkins, Jr.  Dale A. Scherger; Prepared
          for Office of Research  and Monitoring, U.S. Environmental Protection
          Agency, Washington, D.  C., 20460, EPA-R2-72-123,  November, 1972.

      D.   Arnmonia_and_SYnt hes is_Gas

          by Robert Noyes; Noyes  Development Corporation, Mill  Road  at  Grand
          Avenue Park Ridge,  New  Jersey,  07656.

      E•   Industrial Pollution Control^Handbpok

          by Herbert F. Lund; McGraw Hill Publishing Co., New York, Library of
          Congress Catalog Card Number 70-101164.

      F•   Gauging and iSampling_Industrial_Wastewater

          by Joseph G.  Robasky and  Donald  L.  Koraido  Calgon  Corporation;
          Chemical  Engineering  Magazine,   Vol.  80,  No. 1, January 8, 1973,
          Pages 111-120.

      G«   Environmental  Protection  Agency  Study  Report  Industrial   Waste
v
          Group  6   Fertilizers  prepared by Wellman-Powergas.  Inc.; Lakeland,
          Florida,   33803,  for Environmental Protection  Agency,  July,  1971,
          Contract  No.  68-01-0029.

          The Phosphate_IndustrY_in^the_ynitedj-iStates

          by E.G. Houston Tennessee Valley Authority, Office  of  Agricultural
          and  Chemical  Development,  Division of Chemical Development, Muscle
          Shoals, Alabama,  July,  1966.
                                           141

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I.   Commercial Fertilizer         ^^

    Walter W. Brown Publishing Co., Inc. 75 Third Street, N.W.  Atlanta,
    Georgia,   30308.

J-   Characteristics  cf  the  World  Fertilizer  Industry  -  Pho§£h§tic
    Fertilizers

    by  Travis  Hignett,  Director  of  Chemical  Development, Tennessee
    Valley Authority, Muscle Shoals, Alabama, December 1967,  TVA Peport
    No. S-422.

D-   World^Fertilizer Forecast 1965-1980

    by Wellman-Lord, Inc. Lakeland, Florida, Copyright  1967,  Paramount
    Press, Inc., Jacksonville, Florida.

L.   Economic Impact of  Water  Pollution  Control  Beguirements  on  the
    Fertilizer Manufacturing Industry

    by Development Planning and Research Associates, Inc., P.O. Box 727,
    Manhattan,   Kansas,    66502.    Interim  Report  to  Environmental
    Protection Agency, Contract No. 68-01-0766,  November, 1972.

                           1968-.1973

    Chemical  Products  Series  Report-May   1969,   Stanford   Research
    Institute; Menlo Park, California,  94025.

N.   Phospjiatic Fertilizers - Properties and^Prpcesses

    by David W. Bixby, Delbert L. Rucker, Samuel L.  fisdale,  Technical
    Bulletin No. 8, October 1966, The Sulphur Institute, 1725 "K" Street
    Northwest Washington, D.C. 20006.

0.   New Developments in Fluoride  Emissions  From  Phosphate  Processing
    Plants            ~  ~

    by  Frank  L.  Cross, Jr. and Roger W. Ross JAPCA, Volume 19, No.  1,
    Page  15, January, 1969.

P.  The   Chemical	Industry	Facts	_Bock    by   Manufacturing   Chemist
    Association,   Inc.,   5th  Edition 1962,  1825  Connecticut  Ave.,
    Washington, D.C., Library of Congress Catalog Card No.  59-15407.

Q-  Water^Quality  Cr iteria

    National  Technical  Advisory   Committee,  Federal  Water   Pollution
    Control Administration, Washington, C.C.,   1968.

R.  Handbook_of_Dangergus_Materials

    N.I Sax, Reinhold Publishing Corp.  New  York, New York,  1951.
                                     142

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s •  Nitra-tes in^Human_Health

    C. J. Mansfield, Missouri Agricultural Experiment  Station,   Special
    Report No. 55, Pages 37-38, 1965.

T•  Industrial Water_Follutj.on_CQntrol

    W. W. Ekenfelder, McGraw-Hill Publishing Co.,  New  York,  Published
    1966, Library of Congress Catalog Card No.66 - 17913.

u-  Phosphorus and lts_Cgmpounds

    John R. Van Wazer, Interscience Publishers, Inc., New   York   (1961),
    Library of Congress Card No. 58-10100.

V.  Cadmium in Rock Phosjahate^Ores

    H.P. Nicholson, PH.E.,  Director  Southeast  Environmental  Research
    Laboratory (6/19/73).

w-  Standard Methods for the Examination of Water and Waste Water^   13th
    edition, American Public Health Association  (1971).

x-  M§£hods for Chemical Analy_sis of Water  and  Wastes^  EPA,  National
    Environmental    Research   Center,   Analytical   Quality    Control
    Laboratory, Cincinnati, Ohio (1971).
                                     143

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                              SECTION XIV
                                GLOSSABY


All underlined numbers within  a  chemical  formula  represent  normally
subscripted  numbers.   For  example,  H20  represents  water.  Physical
limitations of the printing device make this system necessary.

Aerobic
    Living in the presence of oxygen.

Algae
    A group of aquatic nonvascular plants with chlorophyll.

Anaerobic
    Living in the absence of free oxygen.

Apatite
    A natural calcium phosphate usually containing fluorine occuring  as
    phosphate rock.

Biological Process
    The process by which bacteria and other micro-organisms in search of
    food,  breakdown  complex organic materials into simple, more stable
    substances.

Biuret
    NH2CONHCONH2  •  H2C.   Also  referred  to  as   allophanamide   and
    cabamylurea.

Boiler Blowdown
    A small amount of bciler feed water wasted to remove the build up of
    contaminants frcw the boiler.

Boiler Feed Water Make-up
    Water  that  is  acceptable  for  steam  generation in high pressure
    boilers.

Contaminated Waste Water
    Effluent waste water that has been contaminated due to contact  with
    process  water   (could  be  cooling  tower,  boiler blowdown or pond
    water)

Cooling Water Blowdown
    Small quantity of cooling water discharged from a recycling  cooling
    water system to remove concentrated contaminants from the tower.

Deionized Water
    Water (raw, filtered or treated)  that had certain ions removed by an
    ion exchange unit.

Denitrification
                                   145

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    An  anaerobic  process  which  converts nitrate nitrogen to nitrogen
    gas.

Dissolved Oxygen
    Amount of free oxygen dissolved in water.

Exemplary
    The term used for plants or units within plants  that  exhibit  well
    operated  treatment schemes or in-plant techniques that qualify them
    as best practicable control  technclcgy  currently  available,  best
    available  technology  economically achievable, or best demonstrated
    technology.  Such plants or units may belong to  another  industrial
    category  whose  technology may be transferred to the industry onder
    study.

GTSP
    Granulated triple superphosphate.

Nitri fication
    Conversion of nitrogenous matter into nitrate by bacteria.

Pond Water
    Water used  in  the  manufacture  of  phosphoric  acid  and  related
    compounds to remove heat, convey gypsum and scrub contaminants.

Prills
    Small   round   or  aciciilar  aggregates  of  a  material  that  are
    artificially prepared.

Process water
    Any water which, during the manufacturing process, comes into direct
    contact with any raw material, intermediate, product, by-product, or
    gas or liquid that has accumulated such constituents.

Raw Water
    Water that has not been treated in any way, taken  from  a  well,  a
    river, a lake, or other non-contaminated source.

ROP
    Run-of-pile triple superphosphate.

Single  Train Plant
    A   plant   (especially  an  ammonia plant) that employs a single very
    large  production  unit  with  a  high  degree  of  maintenance-free
    reliability.   This  is  in  contrast  to ct double train plant which
    employs 2 identical units run in parallel with a  lesser  degree  of
    reliability,  but  which  has  the  advantage  of  maintaining  some
    production when one unit is down.

Ton
    All uses of the term "ton" imply short ton equal to 2000 Ib.

Treated Water
                                     146

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           Raw water or filtered  water  that  has  been  treated  to  make   it
           suitable for plant needs  (such as softening).

       TSP
           Triple superphosphate.
  T
»
                                            147

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                                    TABLE 4

                                METRIC  UNITS

                               CONVERSION  TABLE
MULTIPLY (ENGLISH UNITS)

   ENGLISH UNIT      ABBREVIATION
                            ft
acre                    ac
acre - feet             ac
British Thermal
  Unit                  BTU
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 Hg
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             TO OBTAIN (METRIC UNITS)

                                     CONVERSION  ABBREVIATION  METRIC  UNIT
           hectares
           cubic me ters
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
ha
cu m
kg cal
kg cal/kg
cu m/min
cu m/min
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
km •
                                   (0.06805 psig +l)*atm
                                      0.0929
                                      6.452
                                      0.907

                                      0.9144
sq m
sq cm
kkg
                                                    m
kilogram-calories
kilogram calories/
 kilogram
cubic meters/minute
cubic metcrc/ir.inntc
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
killowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres
 (absolute)
square me ters
square centimeters
metric tons
 (1000 kilograms)
meters
                                                                                     J
* Actual conversion, not  a  multiplier
                               Environcental Protection Agency
                               Region V, Library
                               £T; South Dearborn Street
                               Chicago, mtnols 60604
                                       148

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