EPA
   Development Document for Effluent Limitations Guidelines
   and New Source Performance Standards for the
   BASIC FERTILIZER CHEMICALS
   Segment of the
   Fertilizer Manufacturing
   Point Source Category
                    MARCH 1974
         \   U.S. ENVIRONMENTAL PROTECTION AGENCY
         I         Washington, D.C. 20460

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                  DEVELOPMENT DOCUMENT

                            for

             EFFLUENT LIMITATIONS GUIDELINES

                            and

            NEW SOURCE PERFORMANCE STANDARDS


                         for  the

        BASIC FERTILIZER CHEMICALS SEGMENT OF THE
                FERTILIZER  MANUFACTURING


                  POINT SOURCE CATEGORY
                    Russell  E.  Train
                      Admini strator

                      Roger  strelow
Acting Assistant Administrator for Air & Water  Programs
                       Allen  Cywin
        Director, Effluent Guidelines Division

                    Elwood E.  Martin
                     Project  Officer
                       March,  1974

              Effluent Guidelines Division
            Office of Air and  Water Programs
          U.S.  Environmental Protection Agency
                Washington, D.  C.   20U60
   For sale by the Superintendent of Documents, U.S. Government Printing Office, Wellington, D.C. 20402- Price $2

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                            ABSTRACT

This document presents the findings of an extensive study of  the
fertilizer  industry  for  the  purpose  of  developing  effluent
limitation guidelines for existing point sources and standards of
performance  and  pretreatment  standards  for  new  sources   to
implement  sections  304,  306  and  307  of  the  Federal  Water
Pollution Control Act, as amended  (33  U.S.C.  1551,  1314,  and
1316, 86 Stat. 816 et. seg.)(the "Act").

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
   I     Conclusions                                             1
  II     Recommendations                                         3
 III     Introduction                                            7
  IV     Industry Categorization                                 65
   V     Waste Characterization                                  69
  VI     Selection of Pollutant Parameters                       81
 VII     Control and Treatment Technology                        95
VIII     Cost, Energy and Nonwater Quality Aspect                131
  IX     Effluent Reduction Attainable Through the
           Application of the Best Practicable Control
           Technology Currently Available — Effluent
           Limitations Guidelines                                143
   X     Effluent Reduction Attainable Through the
           Application of the Best Available Technology
           Economically Achievable — Effluent Limitations
           Guidelines                                            151
  XI     New Source Performance Standards                        155
 XII     Acknowledgments                                         159
XIII     Bibliography                                            161
 XIV     Glossary                                                165

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                             FIGURES



1.       Nitrogen Fertilizers Plant Locations                    17



2.       Phosphate Fertilizers Plant Locations                   21



3.    .   Sulfuric Acid Plant Single Catalysis                    26



4.       Sulfuric Acid Plant Double Catalysis                    27



5.       Rock Grinding                                           31



6.       Wet Process Phosphoric Acid H2SOf£ Acidulation           34



7.       NPK Process Nitric Acid Acidulation                     36



8.       Wet Phosphoric Acid Concentration                       38



9.       Merchant Grade Phosphoric Acid Clarification            49



10.      Normal Superphosphate                                   42



11.      Triple Superphosphate (Run-of-Pile R.O.P.)              45



12       Granulated Triple Superphosphate                        47



13.      Monoammonium Phosphate Plant                            50



14.      Diammonium Phosphate Plant                              51



15.      Ammonia Plant                                           54



16.      Urea Plant                                              58



17.      Ammonium Nitrate Plant                                  51



18.      Nitric Acid Plant                                       53



19.      Sulfuric Acid Effluent Control                          97



20.      Pond Water Treatment



21.      Gypsum Pond Water Seepage Control
22.      DAP Self Contained Process                              106



23.      Wet Process Phosphoric Acid System                      108



24.      Sulfuric Acid Dilution with Pond Water



25.      Ammonia/Condensate Stripping



26.      Integrated Ammonia/Condensate Stripper Unit             113



27.      Ammonia/Condensate Air Stripping                        115
                                    VI

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28.      Urea Hydrolysis                                         119



29.      Urea Hydrolysis                                         120



30.      Biological Treatment                                    124



31.      Ion Exchange                                            126



32.      Oil/Grease Removal System                               128



33.      Ammonium Nitrate Effluent Utilization                   129
                                    vii

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                             TABLES

1.  Integration of Production in the Fertilizer Industry             15

2.  Water Effluent Treatment Costs Phosphate Subcategory             134

3.  Water Effluent Treatment Costs
    Nitrogen Fertilizer Subcategories                                137

U.  Metric Units Conversion Table                                    168
                                   viii

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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 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
Phosphate Subcategory
 -  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 except as 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, 21 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
    phosphorus   (P)
    fluoride as (F)
    total suspended
      nonfilterable
      solids
Maximum daily
concentration

   mg/1

    70
    30
    50
Maximum average of daily values
for periods of discharge covering
10 or more consecutive days
    mg/1
    35
    15
    25
         The pH of the water discharged shall be within the range
         of 8.0 to 9.5 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 event 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
                       SJOStJSlY.  daily  monthly  daily  Ejonthly  daily
Ammonia  (as N)
kg/kkg  (lb/1000)
  of product           O.C625   0.125  0.025    0.05   0.055    0.11

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 Subcategpry

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

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Ammonia (as N)
kg/kkg (lb/1000 Ib)
  of product
  nonprilled urea
  prilled urea
    BPCTCA
monthly daily
                                        BATEA
0.0375  0.075  0.015
0.05    0.1    0.015
0.03  O.C325  0.065
0.03  0.0325  0.065
Organic Nitrogen  (as N)
kg/kkg (lb/1000 Ib)
  of product
  nonprilled urea      0.175
  prilled urea         0.50
        O.UU   0.025   0.05  0.12    0.2H
        1.25   0.0375  0.075 0.35    0.7
The above monthly limitations represent the  maximum  average  of
daily  values  for  any period of 30 consecutive days.  The daily
maximum average is greater than the 30  day  maximum  average  as
shown.  pH shall be within the range of 6.0 to 9.0 at all times.
Ammonium Nitrate Subcategory

The  proposed  effluent  limitations  for  the  ammonium
subcategory are listed in the following table.
                                   nitrate
                           BPCTCA
Ammonia (as N)
kg/kkg  (lb/1000 Ib)
  of product
  nonprilled AN
  prilled AN

Nitrate (as N)
kg/kkg  (lb/1000 Ib)
  of product
  nonprilled
  prilled
                   BATEA         BADCT
                                monthly
0.0375    0.075  0.0075  0.015  0.025
0.1       0.2    0.0075  0.015  0.05
0.05      0.1    0.0125  0.025  0.0125
0.11      0.22   0.0125  0.025  0.025
                  0.05
                  0.10
                  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 subcateggrv

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  Develogment  of   the   Effluent
LilDiiliiSnS 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-plant and end-of-process technologies, which are  existent  or
capable  of being designed for each segment.  It also included an
identification  of,  in  terms  of  the  amount  of  constituents
(including  thermal)  and  the  effluent level resulting from the
application of each of the treatment  and  control  technologies.
The  problems,  limitations  and  reliability  of  each  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  energy
requirements   of  each  control  and  treatment  technology  was
identified as well  as  the  cost  of  the  application  of  such
technologies.

The  information,  as outlined above, was then evaluated in order
to determine what levels  of  technology  constituted  the  "best
practicable  control  technology  currently available," the "best
available technology  economically  achievable,"  and  the  "best
available  demonstrated  control technology, processes, operating
methods,   or   other   alternatives."    In   identifying   such
technologies,  various  factors  were considered.  These included
the total cost of application of technology in  relation  to  the
effluent reduction benefits to be achieved from such application,
the  age  of  equipment  and  facilities  involved,  the  process
employed, the engineering aspects of the application  of  various
types  of  control  techniques, process changes, nonwater quality
environmental impact  (including energy requirements),  and  other
factors.

                                     8

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Delineation of Study

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                                                 sic

Sulfuric Acid
     Sulfur burning only.                                 2819

Phosphoric Acid
Including phosphate rock grinding when it is performed
on the immediate vicinity of the acid production unit.    2874

Phosphoric Acid concentration                             2874

Phosphoric Acid Clarification                             2874

Normal Superphosphate                                     2874

Triple superphosphate                                     2874
Both run-of-pile and granulated processes

Ammonium Phosphates                                       2874

Ammonia                                                   2873

Urea                                                      2873

Ammonium Nitrate                                          2873
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.

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3ases for Definition of Technology Levels

The  validated  data and samples described in the foregoing pages
were the primary basis for  choosing  the  levels  of  technology
which  were  considered  to  be  the  "best  practicable  control
technology currently available", the "best  available  technology
economically  achievable,"  and  the "best available demonstrated
control  technology,  process   operating   methods,   or   other
alternatives".   This  selection of the separate technologies, of
necessity, required consideration of such additional  factors  as
evaluation of the engineering and operational problems associated
with  the technology, effect on existing processes, total cost of
the technology in relation to the effluent reduction  that  would
be  realized,  energy requirements and cost, the range of control
variations on contaminant concentration and/or quantity, and non-
water quality environmental impact.   Information  regarding  the
influence  of these diverse factors was obtained from a number of
sources.  These sources include government research  information,
published    literature,    trade    organization   publications,
information from  qualified consultants, and cross reference with
related 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^ cont aminant^Leyel

    Installations with low  effluent  contaminant  concentrations
    and quantities.

    3)   Effluent Treatment Method and^Effectiveness

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

    **)   Water^Manaofement 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 Pollution 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)   Geographic IjOcation

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

    8)   Management^Ogerating^jPhilosQphy

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

    g)   Raw Materials

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

    10)   Divers it Y^of_Proc.esses

    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, 34, 37).  These  organizations  had  data
and  plant information obtained from permit application, in-house
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 association  for
comments and suggestions.
                                     11

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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 association.  This was followed
with a second contact by the 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 monitoring of individual processes, and
a  plant  inspection  trip.   A  variety   of   situations   were
encountered.   These  ranged  from  decisions  not  to  include a
specific  plant,  although  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 Collection and Validation of Data

The  most  important  item in a study of this nature is to obtain
data representative of a given process under  all  conditions  of
operation  and  range  of production rates.  Steps and procedures
used in selecting data, stream sampling, and sample analysis were
all designed to accomplish this goal to the best possible degree.

An important step toward this objective  was  the  assignment  of
only  highly  experienced  operating personnel to the field work.
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


                                   12

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when  such  a procedure is followed on a routine basis, upset
process condition,  operation  at  above/below  plant  design
rate, and during shutdown conditions if effluent flow occurs.

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

4)    Establishment  of  the  existence  of  flow  measurement
devices   and/or  other  means  of  quantitatively  measuring
effluent flows.

5)    Making positive identity of  the  type,  frequency,  and
handling of the samples represented by collected data - i.e.,
such  items  as  grab, composite, or continuous 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 DESCRIPTION^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~t»50  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  (K£0).   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
    Ingredient  19.65  1970  1975  19£0 _Rate_  _Rate	Increase

    N            4.5   7.2  11.6  16.9   10%     9%      215%
    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 P2O5 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  P2O5  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
                                    14

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                                                  Table 1
                           Intergration of Production in the Fertilizer Industry
No. of
Companies NH3 U N.A. A.N. S.A.
22 X
2 X
2 X
X X
3 X X X
3 11
1
3 I/
6
1 XX
7 I/
3 11
IX ll
1 I/
3 X
IX X
2 X X
13 XX
5 X XX
3 XXX
1 XXX
16 X X X X
1 XX
2 X XX
1 XXX
4 X X X X
1 X X X X I/
1 X XX
i x x x x
2 X X
1 X
2 X
2 X X
1 X X X
1 X
1 x x
3 X
7 X
1 X
IX X
IX XXX
1 X X X X X
No. of
Wet A. P. TSP SPA Plants
22
2
2
12
9
X 3
X 1
X X 6
X 6
X 3
XX 14
XXX 9
XXX 4
X X X X 4
6
3
4
26
15
9
3
64
X 3
X 8
X 4
X 20
XX X 7
4
5
4

XX 6
XX 8
XX 5
XXX 4
XXX 5
X XXX 15
14
XX 4
XXX 6
4
5
_ _
160
                                                                                                             _ 7
                                                                                                             390
J^/ Not identified individually in data used to develop this list, but must assume existence
   of sulphuric acid facility as intermediate to wet acid production.
21 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
                                                      15

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which   contain  only  a  single  major  plant  nutrient.   Mixed
fertilizers are defined  as  those  which  contain  two  or  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 Fertilizers

              Phosphoric Acid             Ammonium Phosphates
              Normal Superphosphate
              Triple Superphosphate

Nitrogen Fertilizer Industry

Nitrogen based fertilizers have in the  past  realized  both  the
greatest consumption and industry growth rates of the three basic
fertilizer  nutrients   (N,  P2O.5  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  P2O!5
and  K2O  fertilization  within one or two years.  This lead time
and/or the realization of the need for P2.O5 and K2O  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 coke
oven gas, supplied the 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
                                    16

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                                              FIGURE  1
   AMMONIA
PLANT LOCATIONS
                                                                                      AMMONIUM NITRATE
                                                                                        PLANT LOCATIONS
     UREA
 PLANT LOCATIONS
                                                                                            NITRIC ACID
                                                                                         PLANT LOCATIONS

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tons/year).   Locations  of  nitrogen   fertilizer   plants   are
indicated  on Figure 1.  Ammonia plant locations 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, representing the more modern
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 common, 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 of 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  2UO,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
                                    18

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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.

Currently there are 83 plants located (see Figure 1) in the  U.S.
ranging  in  capacity  from  9yOOO to 295,000 kkg/year  (10,000 to
325,000 tons/year).  Approximately 50%  of  the  production  from
these  plants is used as fertilizer and the balance as explosives
and other industrial use.  The majority are small and  have  been
in service for many years.

Use  of urea (46%N) as a source of fertilizer N has been a fairly
recent development which was prompted by shipping costs.  In 1957
approximately 2% of the U.S. fertilizer nitrogen was supplied  by
urea.   Consumption has increased at an annual 17% a year rate to
approximately 12% of the total in 1971,  a four fold  increase  in
the  past  10  years.   It is expected that this growth rate will
continue.

There are 59 operational  plants  (see  Figure  1)   in  the  U.S.
ranging  in  capacity  from  7,000  to 350,000 kkg/year (8,000 to
385,000 tons/year).  Approximately 75% of the total production is
used as fertilizer N with the balance used for  cattle  feed  and
urea-formaldehyde resins.  Urea contains the highest percent N of
any  solid  fertilizer.   This,  plus  the fact that there are no
storage and handling explosion hazards,  ensures  that  urea  will
continue to be a popular fertilizer material.

PhosphateFertilizer Industry

The  phosphate  fertilizer  industry  has not had the spectacular
technical developments that the nitrogen industry has shown,  but
in  the  past  20  years  there  have  been  dramatic  changes in
production facilities, costs and industry image.

Prior to 1955 phosphate was  considered  to  be  the  major  U.S.
fertilizer  nutrient.   The majority of phosphate nutrient was in
the form of  normal  superphosphate  which  has  a  nominal  P2O5
percentage  of  19- 20%.  The low production costs and simplicity
of this process resulted in the  material  being  produced  in  a
myriad  of  small  plants throughout the market area.  Since 1955
normal  superphosphate's  share  of  the  phosphate  market   has
steadily  decreased  and has been replaced with more concentrated
phosphate materials necessitating  utilization  of  special  unit
operations  equipment  and  instrumentation  designed to optimize
system control and efficiencies.  In short, art and mud chemistry
was displaced with  scientific  methods,  definition  of  process
variables,  and  development  of  control  methods.   In order to
manufacture merchant grade phosphoric acid, triple superphosphate
and ammonium phosphate in quantity, it  was  first  necessary  to
modernize  and  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  P2C^5 as phosphoric acid) .  In the early
1960's, 550 kkg/day  (600  tons/day)   sulfuric  acid  plants  were
                                   19

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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 - 180C  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 filtra-
tion.  By 1965, single train phosphoric  acid  units  and  single
unit  operations  equipment  with  capacities of 450 kkg/day (500
tons/day)  P2O5_ became commonplace followed with  an  800  kkq/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 other 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 other 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
River,  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  in  preparing  liquid  fertilizer
solutions.  Merchant grade acid is low strength  (30%  P2O5)   acid
which  has been concentrated to 52-54% P.2O5 and then processed to
remove 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  the  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%  H2SiF6)  as  a  by-product  of  the
phosphoric acid concentration or sulfuric acid  digestion  steps.
                                    20

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 FIGURE   2
I'HOIH'IIOKIC ACID
IH.ANT UH'ATIONS
   GTSP,ROP,TSP
  PLANT LOCATIONS
       MAP/DAP
  AMMONIUM PHOSPHATE
    PLANT LOCATIONS
    21

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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)  P2O5  (See  Figure
2) .   Five  sizeable,  new  plants  are  currently  in design and
construction stages and will be 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 195C  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
phenomenon of the phosphate  industry.   This  category  includes
both  monoammonium   (MAP)  and diammonium (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% P2O^ 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
                                  22

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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) .
                                     23

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                            Specific

                      Process^DescriPtions

Phosphate Fertiliser 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 basic 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
months per year.
                                     24

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                          Sulfuric 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  palletized  vanadium pentoxide catalyst to form
resultant sulfur trioxide (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
(SO3)   gas is  hydrolyzed with water to form product sulfuric acid
(H2.SCW) .  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)  10056 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
                                     25

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                                                                                         	k. TO ATMOSPHERE
FEED STREAM
                       TREATED H2O
                     (310 ~ 400 GAL/TON)
                     1300- 1670 l/kkg
                         SULFUR
                         FURNACE
                         CONVERSION
ABSORPTION
                            t BOILER SLOWDOWN
                              (5-10 GAL/TON)
                            j 21-40 l/kkg

                            	1
                                                                                      (18,000
                                                                                       75,000
                                                      ACID
                                                   CIRC. TANK
           PROCESS I-LO
                                  2080 l/kkg
                            (450 ~ 500 GAL/TON)
         (15- 20 GAL/TON)
         63 - 83 l/kkg
     STREAM LEGEND
      —•	 MAIN LIQUID
      — — — MAIN GAS
      •_	'_\ MINOR
                TON - SHORT TON
              FIGURE  3


SULFURIC ACID PLANT (SINGLE CATALYSIS)
      FLOW RATES PER TON 100% H2SO4
                                                           20,000 GAL/TON)
                                                           83,000 l/kkg

-------
                                                                                           STREAM LEGEND
                                                                                                  MAIN LIQUID
                                                              t
                                                              I
                                                          OFF GAS
          FEED STREAM    	
                                     1670 l/kkg
1875 ~ 2080 l/kkg
(450 ~ 500 GAL/TON)
  BLOW DOWN
                                                             T
                         	MAIN GAS
                         	[ MINOR
     75,000 ~ 83,500 l/kkg
     (8,000 ~ 20,000 GAL/TON)

ED

R
:E
i_| r\ 1
H20 |_
BOILER

r*
v 1

STEAM

1
WASTE
HEAT
BOILER
BLOWDOWNl 	 .
5-10 GAL/TON) 21
t


i
^
T
	 *-*
CONVERSION
+-T-
|_ 1
~ 40 l/kkg ~~1 !
i !
ACID



                                                 COOLING &
                                                  PUMPING
    ABSORPTION
           -J
INTERSTAGE
ABSORPTION
                                                                                                     PRODUCT
                                                                PROCESS WATER
(15
 63.
20 GAL/TON)
83 l/kkg
        TON - SHORT TON
                                                     FIGURE   4
                                    SULFURIC ACID PLANT - DOUBLE CATALYSIS
                                             FLOW RATES PER TON 100% H,,SO4

-------
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  (S0£).    This  reaction
releases a large quantity of heat which causes the temperature of
the  resultant  SO2  - excess air mixture to rise to 980 - 11UO°C
(1800-2000°F)  as it exits  from  the  furnace.   The  heated  gas
mixture  flows  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 SO2 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   S03  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-current to  downward  flowing
98-99%  H2SOU.   The  SO3  is  readily hydrolyzed to H2SOU by the
water in the acid.  Hydrolysis of the SO3 to E2SOJ4 also  releases
heat which increases the temperature of the enriched 98-99% H2SCW
acid.   After  the  acid exits the tower it flows through cooling
coils to 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  flows 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 into 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% H2SOU) 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


                                    28

-------
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 tow^r  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  SO2J
conversion  to  SO3  and thus a significantly reduced quantity of
SO2 in the plant effluent gas stream.  Double  absorption  plants
realize  SO2  conversion  efficiencies  of 99.5+ % as compared to
single absorption plant efficiencies of approximately 98%.   Both
processes  have  the  same  water  effluent  in  respect  to both
quantity and contaminant levels.
                                    29

-------
                     Phosphate Rock_Grinding

                       Process Description
General
Phosphate rock that has been mined and beneficiated is  generally
too coarse to be used 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  mills  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 lower 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.
                                    30

-------
u>
                                          LEGEND
                                          — MAIN ROCK
                                      	MINOR ROCK

1 pun?; RnrK 1 ^

COOLING WATER
(8~ 150 GAL/TON) |
EXHAUST AIR
t
33~625l/kkg GRINDING ^ DUST
MILL * COLLECTOR
COOLING WATER ]
(8~ 150 GAL/TON)
33 ~ 625 l/kkg
1
'ON ~ SHORT TON
t 1

' ^ oo/-vrvi I/~T

                                                   FIGURE  5

                                                 ROCK GRINDING
                                             FLOW RATE PER TON ROCK

-------
              Phosphate Rock_pigegtionm6.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  to  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  show 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	i_ing_Plants	kkg;/y.ear   Production
     Sulfuric Acid

     Nitric Acid

     Hydrochloric Acid
35*

 4

 0
4,879,000

   61,000

        0
98.77

 1.23

 o
                                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.
                                    32

-------
                         Phosphoric Acid

                       Process Description

Sulfuric Acid Acidulation

The raw materials used in this process are ground phosphate rock,
93X  sulfuric  acid, and water.  Phosphate rock is mixed with the
sulfuric acid after the acid has first been diluted with water to
a 55-70X H2SOU concentration.  This  mixing  takes  place  in  an
attack  vessel of sufficient size to retain the raw material mix-
ture for  several  hours  (Figure  6) .   The  simplified  overall
chemical reaction is represented by the following equation:

     3 Ca3 (PO4)2 (solid)     +    9 H2S04.  (liq)   + 18 H2O  (liq)
         Phos. Rock                  Sulf. Acid     Water

   -> 6 H3POU  (liq)   +   9 CaSOU  .  2H2O  (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  other  plant
equipment  as  either  the gaseous compound silicon tetrafluoride
(SiFjf)  or hydrofluoric acid  (HF) .  SiFj* hydrolyzes  very  quickly
in moist air to fluosilicic acid (H2SiF6)  and silica (SiO2) . Both
     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 digester, the mixture of phosphoric
acid  and  gypsum  is  pumped  to  a  filter  which  mechanically
separates   the  particulate  gypsum  from  the  phosphoric  acid
(approx.  3Q% P2O5 concentration) .   The  magnitude  of  the  by-
product   gypsum  is  best  appreciated  by  the  fact  that  the
production of  each  kkg  of  P2°j>  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.
                                    33

-------
                                             PHOSPHATE
                                                ROCK
                                                           CONTAMINATED
                                                               WATER
u>
-p-
            (0 ~ 4500 GAL/TON)
             0~ 19,000 l/kkg
                               COOLING WATER OUT
(2500 ~ 3500
 GAL/TON)
11000~ 14500
      j  l/kkg
                                                                                  OFF GAS
_^_

 I

 I
 I
                                                                                                          TO ATMOSPHERE
                                                                                               •CONTAMINATED WATER
                     (1300~ 1500 GAL/TON)
                     5400 ~ 6300 l/kkg
                            (1300~ 1500 GAL/TON)
                             5400 ~ 6300 l/kkg
                                                                                                         CONTAMINATED
                                                                                                            WATER
                                                                       14,500 l/kkg
                                                                       3500 GAL/TON)
                                                                        PRODUCT
                                                                          ACID
                                                 STREAM LEGEND
                                                  	MAJOR LIQUID
                                                  	MINOR LIQUID
                                                  	MINOR GAS
                                                                FIGURE   6

                                          WET PROCESS PHOSPHORIC ACID - H2SO4 ACIDULATION
                                                          FLOW RATE PER TON PO

-------
                         Phosphoric Acid

                       Process Description


Nitric Acid Acidulation

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   acidylation   differs   from  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  acidulation  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(POl)2  +  6HN03   —+  3Ca (NO3) 2  +  2H3POU
     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.
                                    35

-------
  FEED STREAM
TON ~ SHORT TON
                     DIGESTION &
                    AMMONIATION
                       DRYING
                    GRANULATION
                       SIZING
                                                           TO ATMOSPHERE
                                                                  I
                                    i
                                    i
                                  —i
PRODUCT
                                                              OFF GAS
                                                              SCRUBBER
                                             FIGURE  7

                              NPK PROCESS NITRIC ACID ACIDULATION
                                                                                           STREAM LEGEND
                                                                                          	  MAIN FLUID
                                         	MAIN GAS
                                   CONTAMINATED
                                       WATER
                                 1000'
                                 (240-
    2300 l/kkg
    540 GAL/TON)
CONTAMINATED
    WATER
                                                                              1000- 2300 l/kkg
                                                                              (240 ~ 540 GAL/TON)
                                       FLOW RATE PER TON P2O5

-------
                  Phosphoric_Acid Concentration

                       Process Description
General
Phosphoric  acid  as  produced  in  the sulfuric acid acidulation
process is generally of too low in concentration (26-30% P205) to
qualify as either a salable product or to be used for  processing
a final dry fertilizer product.  This P205 level can be increased
to  the  40-5456  P2O5  range by processing the acid through water
evaporation units.

Process

Phosphoric acid concentration to 54% P£C)5 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
volatilization 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.
                                     37

-------
                     STEAM
                    CONTAMINATED WATER
                    PHOSPHORIC ACID
00
                    STEAM
                      CONDENSATE
                                               f"
                                              J	
                                                                          EJCT
                                             EVAP.
                                 I
                                   PUMP SEAL WATER
                                   (.2 ~ .4 GAL/TON)
                                   .83 ~ 1.6 l/kkg
   STREAM LEGEND
         MAIN LIQUID
	MAIN GAS
	| MINOR
                                                                               CONCENTRATED
                                                                               PHOSPHORIC ACID
                                                                             CONTAMINATED WATER
(550 ~ 570 GAL/TON)
 2500 ~ 2600 l/kkg
                   TON ~ SHORT TON
                                                      FIGURE  8
                                         WET PHOSPHORIC ACID CONCENTRATION
                                                 FLOW RATE PER TON PO

-------
                  Phosphoric Acid Clarificgtion

                       Process Description
General
Phosphoric  acid  after  concentration  to  a  52-54%  P2O5 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.
                                    39

-------
CONCj PHOS. ACID
    WATER IN  	
   ,165~ 770 GAL/TON)
   690 ~ 3200 l/kkg
                       WATER OUT
                    (165 ~ 770 GAL/TON)
                    690 ~ 3200 l/kkg
 SOLIDS
REMOVAL
                                           SOLIDS PLUS
                                               ACID
MERCHANT GRADE ACID
                          TO DRY FERTILIZER
                          MANUFACTURER
TON ~ SHORT TON
                                              FIGURE   9

                           MERCHANT  GRADE PHOSPHORIC ACID  CLARIFICATION

                                         FLOW RATE PER TON P0OC

-------
                      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 P205
content   (2C%)   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 P2.O5.  The process is
simple  and easy to operate requiring less sulfur per ton of P205_
than the production of phosphoric acid.  The combination  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.

Process.

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

     Ca3(POU)2  +  2H2SOU  +  H2O  —*•  2CaSOU.2H2O + Ca (H2POU) . H20
     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 U 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
                                    41

-------
  CLARIFIED OR CONTAMINATED WATER
                                           940- 1040 l/kkg
                                          (225 ~ 250 GAL/TON)
         TO ATMOS.
  SULFURIC ACID
  PHOSPHATE ROCK
               c
 STREAM LEGEND
——— MINOR PROCESS
	GAS

	 MAIN PROCESS
  TONS ~ SHORT TONS
                                        I	
                                                                            t
                                                                     CONTAMINATED WATER
(225 ~ 250 GAL/TON)
 940- 1040 l/kkg
                                                                   N.S. TO CURING
                                     FIGURE  10


                              NORMAL SUPERPHOSPHATE

                                FLOW RATE PER TON N.S.

-------
acid  with  the  subsequent  decrease  in  free  acid and citrate
insoluble P2O5 content.
                                    43

-------
                      Triple Superphosphate

                       Process^Description

General

Triple superphosphate (TSP), 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 (P04J2  +  4H3P04  + 3H2O —*• 3Ca (H2PO4)2.H2O
  Phosphate      Phosphoric Water      Triple Superphosphate
  Rock           Acid                   (Monocalcium phosphate)

At this point the similarity between the two processes ends.

The ROP process is essentially identical to the normal superphos-
phate process with the exception that phosphoric rather than sul-
furic  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  appearance.
                                    44

-------
       CLARIFIED OR CONTAMINATED WATER
 940 ~ 1040 l/kkg
(225 ~ 250 GAL/TON)
                                                                                            STREAM LEGEND
                                                                                           	 MAIN PROCESS
                                                                                           	GAS
                                                                                           	 MINOR PROCESS
       PHOSPHORIC ACID
       PHOSPHATE ROCK
                    C
Ln
        TON ~ SHORT TON
TO ATMOS.
                                                                                       CONTAMINATED WATER
                                                            ROP ~ TSP TO CURING
                                                                                       (225 ~ 250 GAL/TON)
                                                                                       940 ~ 1050 l/kkg
                                                FIGURE   11

                                         TRIPLE SUPERPHOSPHATE
                                            (RUN-OF-PILE R.O.P.)
                                        FLOW RATE PER TON ROP ~ TSP

-------
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-U  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 (U0%
P2O5) than the U6-5U% P2O5 acid used in ROP  manufacture.   Forty
percent P2_O5 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  to 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.
                                   46

-------
             STREAM LEGEND
                 " MAIN PROCESS
           	GAS
           	 MINOR PROCESS
  CLARIFIED OR CONTAMINATED WATER
 660
(158
750 l/kkg
180 GAL/TON)
                                                                             TO ATM OS.
                                                                              CONTAMINATED
                                                                                 WATER
                                                                              (5 ~ 10 GAL/TON)
                                                                              21 ~ 40 l/kkg
TON ~ SHORT TON
                                                                                     GTSP OUT
                                 FIGURE  12

                    GRANULATED TRIPLE SUPER PHOSPHATE
                            FLOW RATE PER TON GTSP

-------
                       AmmQnium^Phosphates

                       Process Description

Gengral

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  thei£ 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 P2O5
from  DAP  than  from  concentrated  superphosphate.    Such   an
impressive  number of plus factors insure that ammonium 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 phos-
phate present.  The most important ammonium phosphate fertilizers
in use in the U.S. are:

             Mgnoammonium (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 mono-
ammonium  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:


                                   48

-------
     H3PO4    +    NH3     —*•    NH4H2P01
     Phosphoric   Ammonia         Monoammonium
     Acid                         Phosphate

   * H2S04    +   2NH3     —*    (NH4)2SOU
     Sulfuric     Ammonia         Ammonium
     Acid                         Sulfate

*  This reaction occurs only in the production of 16-20-0 and
occurs concurrently with the mon©ammonium phosphate reaction.

The  processing  steps  (Figures  13  and  1U)   are   essentially
identical  to  those  described in the triple superphosphate GTSP
process.  Ammonia, either gaseous or liquid, is reacted with  30-
HQ%  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.
                                    49

-------
Ul
o
                CLARIFIED OR CONTAMINATED WATER
                5000 ~ 6500 l/kkg
                (1200 ~ 1500 GAL/TON)
                  PHOSPHORIC ACID
NH,
^— 	 fc,
1
'f"
REACTOR
                    NH-
 f-
  I      I
    	I
                                                                                         	1
                                           GRANULATOR
                                                1'	I
                                                 DRYER
                                                                                               TO ATMOS
                                                                                                CONTAMINATED
                                                                                                   WATER    ^

                                                                                               (0~ 72 GAL/TON)
                                                                                               0 ~ 300 l/kkg
                                                                                            MAP TO STORAGE
              TON ~ SHORT TON
                   STEAM LEGEND
                  • •      MAIN PROCESS
                  	  GAS
                  	MINOR PROCESS
           FIGURE   13

MONOiAMMONIUM PHOSPHATE   PLANT

       FLOW RATE PER TON MAP

-------
                  PROS. ACID
Ln
                                                                           CONTAMINATED WATER
                                                                           (1200 ~ 1500 GAL/TON)
                                                                           5000 ~ 6500 l/KKg
                                                                       , r   CONTAMINATED WATER
                                                                            (1200- 1500 GAL/TON)
                                                                            5000 ~ 6500 l/KKg
                                         GRANULATION
                                            DRYING
                                            SIZING
DAP
                    TON-SHORT TON
                                                           FIGURE  14
                                                  Dl AMMONIUM PHOSPHATE PLANT
                                                     FLOW RATE PER TON DAP

-------
Nitrogen 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  car.
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 amount 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  seen  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).
                                    52

-------
                             Ammonia

                       Procegs^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 larger sizes.

Ammonia is produced by the reaction of hydrogen with nitrogen  in
a three to one (3:1)  volume (mole) 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 psig) for the smaller plants, less
than  550 kkg/day (600 tons/day), using reciprocating compressors
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 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  ammonia  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-
                                    53

-------
                                     STEAM
                                                                                                    MAKE-UP
                                                                                                     WATER
  STEAM
                                                     CARBON DIOXIDE
                               WASTE HEAT
                                 BOILER
                           BOILER FEED
                             WATER BOILER
BLOW DOWN
     (5 ~ 30 GAL/TON)
HEAT  20-125 l/KKg
01 I
o J
o I
                 GAS
              REFORMING
       £ I FUEL

NATURAL |
  GAS
                   RAW
    GAS
              GAS
          PURIFICATION
                                      SYN. GAS
                   COOL
                   WATER
                           AIR
                  COMPRESSOR
                                   SYN. GAS
                                 COMPRESSOR
                                       REFRIGERATION
                                        COMPRESSOR
                                            AIR
                                        COMPRESSOR
                  SLOWDOWN
                  (30 ~ 50 GAL/TON)  125 ~ 200 l/KKg
                  PROCESS CONDENSATE
                  (5 ~ 200 GAL/TON)
                  20 ~ 835 l/KKg
                                                                AMMONIA
                                                               CONVERTER
                                                             tO
                                                             <
                                                             C3
                                                             CO
                                                             68
                                                       o
                                                       O
                                                                           HEAT
                                                                                           EFFLUENT
                            | RECYCLE GAS
                                                                     AMMONIA
                                                                    CONDENSER
                                                           REFRIGERANT
                                                          AIR FROM ATMOS
                                                      COOLING WATER
 TON - SHORT TON
                                                FIGURE  15

                                             AMMONIA PLANT
                                        FLOW RATE PER TON AMMONIA
                                                                                     FROM CLARIFICATION
                                                                                     3 ~ GAL/TON
                                                                                     12.5~ 20.0 l/kkg
                                                                                          PRODUCT-LIQUID AMMONIA
                                                                                          COOLING TOWER
                                                                                           BLOW-DOWN
                                                                    (400 ~ 800 GAL/TON)
                                                                    1600~ 3200 l/KKg

-------
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 & 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  high  molecular  weight hydrocarbons by
passing the gas through a bed of activated carbon.   The  natural
gas  is  then  mixed  v;ith  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  (1,450°F) with the steam according to the following
reactions:

     CxHy. + H2O   —+   xCO + (y + y/2) H2  (Reform)

     CO + H20     —*     C02 + H2  (Shift Conversion)

The reforming reaction is only partially complete and  the  shift
conversion  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 consume 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, m atm to 102 atm (600 psig  to  1,500  psig),  and
then  into the shift conversion section.  The shift reaction (see
ahove)  is favored by low temperatures and is carried out  in  two
steps with heat recovery between each step.  The first step, high
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
22C°C  (425°F).   Following additional heat recovery and cooling,
where necessary, the gas passes to the CO2 recovery section.
                                     55

-------
The C02 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 C02 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 CO2 remaining.  This is accomplished in a methanation unit
where the" gas  is  passed  through, a  bed  of  nickel  catalyst
resulting in the following reactions:

             C02 * 4H2 -» CH4 *  2 H20

             CO + 3H2  —* CH4 * H20

After  heat  recovery  and  any  necessary cooling the syn gas is
ready for  compression  and  feeding  to  the  ammonia  synthesis
section.
                                     56

-------
                               Urea

                       Process^Descriptiori

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 + C02 —* NH4CO2NH2

    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  be  further
concentrated  to  a  solid  product.   This  solid product can be
formed by prilling, crystallation or a combination of both.   The


                                    57

-------
                                                           PROCESS WATER,
                      BOILER FEED
                        WATER
                      TREATMENT
                  3.
EFFLUENT
                (10 ~30 GAL/TON)
              40~125l/KKg
               AMMONIA  v
                                                             (115~230GAL7TON)
                            CARBON DIOXIDE
Oi
oo
               COOLING H2O
               MAKE-UP
               WATER
i

ERY ~*
DE
i
UJ
Q
>• X
O
CAR BOND
* COOLING H20
CARBON DIOXIDE
COMPRESSOR
	 1

FOR -
|

-+

TO
AMMONIA & CARBON"
DIOXIDE
480~960l/KKg
OTHER PROCESSES
R& WATER VAPOR
<

	 ^
EVAPORATOR
HEAT
*•••«••
STRIPPER
1'
— ¥
L
                                                                                           AIR & WATER VAPOR
                                            HEAT
                                t
                   COOLING TOWER
                                                       PRILL
                                                       TOWER
                                                                                                               CLARIFICATION
                                                                                                                  8.3
                                                                                               EFFLUENT
                                                                                               - 3 GAL/TON)
                                                                                                 1251/KKg
                                                                                     AIR
                                                                                                  UREA PRILLS
                                                               , ,UREA SOLUTION
             TON-SHORT TON
             BLOW - DOWN
        (90 ~ 350 GAL/TON)
           375 ~ 1460 l/KKg
                                                                  FIGURE   16

                                                                 UREA PLANT
                                                            FLOW RATE PER TON UREA

-------
concentration step takes place in flash evaporators designed with
minimum  residence  time  to  prevent  the  formation  of biuret.
(NH2CONHCONH2 • H2O)   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 It biuret while
crystallization only has .IX. A combination of the two  processes.
results in a biuret content of about .5%.
                                    59

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                        Ammon i urn Ni trate

                       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  -*• NH4N03

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 83%  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 concentrated solution is pumped to the top of  a  15
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.
                                    60

-------
          B FW
       TREATMENT
    EFFLUENT
        (3 ~ 17 GAL/TON)
        12.5 ~ 71 l/KKg
                                                                                    AIR & WATER VAPOR
                                                 PROCESS
                                                 CONDENSATE
                                                 (50 ~ 110 GAL/TON)
                                                 200~460l/KKg
        AMMONIA
        NITRIC ACID
                       NEUTRALIZER
            HEAT
                          LU
                          X
                                       EVAPORATOR
                                          LU
                                          X
    CLARIFICATION
                                         AMMONIUM NITRATE
                                             SOLUTION
                                                                 AAAA
                                                                  PRILL
                                                                  TOWER
                                                                              CLARIFIED
                                                                              WATER
                                                                          AIR
                                                                                        COOLING TOWER
                                                                   COOLING, DRYING
                                                                     & COATING
                                                                                                     BLOW - DOWN
(20
83.5
                                                                                                 40 GAL/TON)
                                                                                                 ~ 167 l/KKg
                                                                                 AMMONIUM NITRATE PRILLS
       EFFLUENT
(2 ~ 350 GAL/TON)
8.35 ~ 12.5 l/KKg
                                                            FIGURE  17
TON - SHORT TON
                                               AMMONIUM NITRATE PLANT
                                            FLOW RATE PER TON AMMONIUM NITRATE

-------
                           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 nitrogen which are then
further oxidized and absorbed in water  producing  a  55  to  65%
nitric acid.  The following reactions occur in the process:


     2NO + O2 —*• 2NO2

    3N02 + H20 —> 2HN03 + 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 9.2 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  some  of the water is condensed and
forms nitric acid, the gases are passed up through an  absorptipn
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 out 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/ton)  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 andf 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.
                                   62

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                                                                                                      MAKE-UP WATER
                                                                  TAIL GAS
                                              1250 ~ 2500
                                              ,'KKg
                                                             1
                                                                                                         COOLING
                                                                                                          TOWER
                                                                                                              (300 - 600
                                                                                                              GALTONi
                                                                                                          COOLING TOWER
                                                                                                            BLOW DOWN
                                                                                              (20,000 ~ 40,000 GAL/TON)
                                                                                              83,000 - 167,000 l/KKg
AMMONIA
              TON - SHORT TONS
 (10 ~ 15 GAL/TON)
 42 ~ 63 l/KKg
          FIGURE  18
       NITRIC ACID PLANT
FLOW RATE PER TON 100% NITRIC ACID

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                           SECTION IV
                     INDUSTRY CATEGORIZATIQN

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 or 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 SUBCATEGORY
    1.   Phosphate Rock Grinding
    2.   Wet Process Phosphoric Acid
    3.   Phosphoric Acid Concentration
    a.   Phosphoric Acid Clarification
    5.   Normal Superphosphate
    6.   Triple Superphosphate
    7.   Ammonium Phosphates
    8.   Sulfuric Acid
B.  AMMONIA SUBCATEGORY

                                    65

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C.  Urea Subcategory
D.  Ammonium Nitrate Subcategory
E.  Nitric Acid Subcategory

Industry^Diyision

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  other  following  factors  indicates  that   phosphate
fertilizer  chemicals  should constitute a separate category from
nitrogen fertilizer chemicals.

         with Separation of Individual Process Effluent Within  a
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.

Plant 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 subcategorization
is required.

Effect 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.
                                    66

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Existence, Type and Efficiency of Air Pollution Contro1 Equipment

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 or efficiency of air pollution
control devices, and subcategorization is not warranted.

Land Area Available for 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  1UOO  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  ammonia.
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 subcategorization
of these latter chemicals.

TreatabilityofWastes

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 other hand urea, ammonium nitrate and ammonia can
each require a different  treatment  technique  to  achieve  best
practicable and best available technologies.

Effect of Rainfall - 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


                                    67

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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.
                                    68

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                            SECTION V

                     WASTE CHARACTERIZATION
General

The intent of this section is to describe and identify the  water
usage  and  waste  water  flows in each individual process.  Each
type water usage and effluent is  discussed  separately  and  in-
cludes  a  tabulation  indicating  ranges of flow and contaminant
concentrations for each process.  Flow figures are presented on 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   to
pictorially  indicate  the  various  water  flows relative to the
process equipment.

Phosphate 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
         steam generation.

    B.   Closed Loop Cooling Tower Slowdown

    C.   Boiler Slowdown

    D.   Contaminated Water (Gypsum Pond Water)

    E.   Make-up 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
                                   69

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headings.  Detailed flow diagrams were  previously  presented  in
Figures 3 through 14.


A.Water Treatment Plant Effluent

Basically  only  the  sulfuric acid process has a water treatment
effluent.  This 1300-1670 1/kkg (310-UOO gal/ton)  effluent stream
consists principally of only the impurities removed from the  raw
water  (such  as  carbonates,  bicarbonates,  hydroxides, silica,
etc.) plus minor quantities of treatment chemicals.

The degree of water treatment of raw water required is  dependent
on  the steam pressure generated.  Generally medium-pressure 9.5-
52 atm (125-750 psig) systems are  used  and  do  require  rather
extensive   make-up  water  treatment.   Hot  lime-zeolite  water
treatment is the most commonly used.

There are phosphate complexes particularly along the  Mississippi
River  which  use river water both for boiler make-up and process
water.  In these plants it is necessary to treat the river  water
through a settler 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•Closed Loop Cooling Tower Slowdown

The cooling water requirements and normal blowdown quantities are
listed in the following table.  Effluent limits with  respect  to
thermal  components and rust and bacteria inhibiting chemicals is
cooling tower blowdown or for once through cooling water are  not
covered in this report, but will be established at a later date.
                                    70

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Cooling Water
Process
Circulation Requirement
 1/kkg          gal/ton
          Discharge Requirement
           1/kkg           gal/ton
Sulfuric Acid  75000-83000
(per ton 100%)
H2SOJJ
              18000-20000   167C-2500
Rock Grinding
(per ton rock)

Phosphoric Acid
(per ton P2O5)

Phos. A. Cone.
(per ton P2O5)
   33-625
    0-19000
    None
Phos. A. Clarifi- 690-3200
cation
(per ton P2O5)

Normal Super       None
(per ton product)

Triple Super       None
(per ton product)

Ammon Phos.        None
(per ton product)
8-150
0-t500
None
                165-770
                  None
                  None
                  None
33-625*
 0-19000*
 None
           690-3200*
             None
             None
             None
                         UOO-600
8-150*
0-4500*
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.

The  table  below lists the normal range of contaminants that may
be found in cooling water blowdown systems.
                                   71

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              Contaminant                    concentration

                                                 mg/1

               Chromate                          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 • Bo j.ler^ 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.

        Contaminant                            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  (Gypsum Pond 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  impounded  and  reused water accumulates
sizeable  concentrations  of  many  cations   and   anions,   but
particularly  F  and  P.   Concentrations  of  8500 mg/1 F and in
                                   72

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excess of 5000 mg/1 P are not unusual.  Concentration  of  radium
226 in recycled gypsum pond water is 60-100 picocuries per liter.
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-up water
    1/kkq

None
    None
16400-20800

1000-2300

2500-2600

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

 None
     None
 3800-5000

 240-540

 550-57C

 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 or to the contaminated water system.
                                    73

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     Process                      Make-up Water Usage

                               1/kkq           gal/ton
 Sulfuric Acid                 63*83           15-20
 Rock Grinding                 None            None
 Wet Process Phosphoric Acid   None            None
 Phosphoric Acid Concentration 0.8-1.6        0.2-0.4
 Phos Acid Clarification       None            None
 Normal Superphosphate         None            None
 Triple Superphosphate        NNone            None
 Ammonium Phosphates           None            None

F.Spills and Leaks

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.

G.Non-Point Source Discharge

The  primary origin of such discharges is dry fertilizer material
which dusts over the general plant area  and  then  dissolves  in
rain  or  melting snow.  The magnitude of 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 ^Gypsum Pond^Water}  Treatment System

The contaminated water treatment system discharge effluent is the
only major discharge stream from a phosphoric acid complex  other
than the water treatment and blowdown 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.   Normally,  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
                                    74

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strictly dependent upon the design of the  treatment  system  and
has  no  direct  connection  to production tonnage.  Contaminated
water treatment systems generally have  capacities  of  2085-4170
1/min (500-1000 gpm).

The common treatment system is a two-stage liming process.  Three
main  contaminated  water  parameters,  namely  pH,  Ff and P are
addressed.

Cadmium, Arsenicj Vanadium, Uranium and Radium 226

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.  Radium 226  is  a  decay
product  of uranium that occurs in the recycled gypsum pond water
in the 60-100 picpcuries/ liter range.  However, its presence  in
the  effluent  is  controlled  with  control  of  phosphorus  and
fluoride.

                                       Phosphate^ Rock
                                           (ppm)
         Element                 Florida       Western

      Arsenic as As03              5-30          6-140
      Cadmium as CdO~                10            150
      Uranium as U30J3            100^200        50-100
      Vanadium as V203            10-200       400-4000
                                    75

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Nitrogen Fertilizer 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 tower 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
Figures 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  to  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 Tower Blowdown

The cooling water requirements and expected blowdown requirements
for  the  four process plants in the nitrogen fertilizer industry
are listed in the table below.
                                    76

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                                      Cooling Water

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

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

Urea           41,700 to    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 to    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 tower, 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 cooling system blowdown 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 comes  in
with  make-up,  is  ammonia.  Due to the proximity of the cooling
tower  in  relation  to  any  of  the  four  nitrogen  fertilizer
operations,  some  atmospheric ammonia is 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  effluent.   Effluent
                                    77

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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 Ib 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  (1,5CO
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 to  boilers  to  prevent  corrosion  and
scale formation throughout the system.

The  combination  of  make-up  water  quality and the addition of
inhibitor chemicals necessitates blowdown 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/ton) of
product.

Typical compositions of  contaminants  in  boiler  blowdown  from
nitrogen complex boilers are as follows:


                mg/1                          mg/1

Phosphate       5-50       Suspended Solids   50-300
Sulfite         0-100      Alkalinity         50-700
TDS           500-3500     Hardness           50-500
Zinc            0-10       Si02               10-5C
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 blowdown 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.
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Due  to  the nature and expense of reciprocating compressors they
are usually replaced by centrifugal compressors, when the ammonia
plant 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  to 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  condensate  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, am-
monium carbamate, ammonia and carbon dioxide.   The  quantity  of
this stream will range from 417 to 935 1/kkg (100 to 225 gal/ton)
of  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 Condensate

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  strearr
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/100C
kkg  (300  lb/1000  ton) and ammonium nitrate at 7000 kg/1000 kkc
(14,000 lb/1000 ton) of ammonium nitrate product.

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

F.Collected Spills and Leaks

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 on 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 Discharges

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.
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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 includi
        in process effluent streams

                  PHOSPHATE FERTILIZER INDUSTRY

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

Secondary parameters which should be monitored but do not warrant
establishment  of  guidelines  are:    ammonia,  total  dissolved
solids,  temperature,  cadmium,  total  chromium, zinc, vanadium,
arsenic, uranium and  radium  226.   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.

                  NITROGEN FERTILIZER INDUSTRY


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

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, oil
and grease, 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
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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

Phosphorus

During the past 30 years, a formidable case has developed for the
belief that increasing standing crops of aquatic  plant  growths,
which  often  interfere with water uses and are nuisances to man,
frequently are caused by increasing supplies of phosphorus.  Such
phenomena  are  associated  with  a  condition   of   accelerated
eutrophication  or  aging  of waters.  It is generally recognized
that phosphorus is not the  sole  cause  of  eutrophication,  but
there  is  evidence to substantiate that it is frequently the key
element in all of the elements required by fresh water plants and
is generally present  in  the  least  amount  relative  to  need.
Therefore, an increase in phosphorus allows use of other, already
present,  nutrients  for  plant  growths.   Phosphorus is usually
described, for this reasons, as a "limiting factor."

When a plant population is stimulated in production and attains a
nuisance status, a large number  of  associated  liabilities  are
immediately  apparent.   Dense  populations  of  pond  weeds make
swimming dangerous.   Boating  and  water  skiing  and  sometimes
fishing  may be eliminated because of the mass of vegetation that
serves as  a  physical  impediment  to  such  activities.   Plant
populations  have  been  associated with stunted fish populations
and with poor  fishing.   Plant  nuisances  emit  vile  stenches,
impart  tastes and odors to water supplies, reduce the efficiency
of industrial and municipal  water  treatment,  impair  aesthetic
beauty,   reduce  or  restrict  resort  trade,  lower  waterfront
property values, cause skin rashes to man during  water  contact,
and serve as a desired substrate and breeding ground for flies.

Phosphorus  in  the  elemental  form  is  particularly toxic, and
subject to bioaccumulation in  much  the  same  way  as  mercury.
Colloidal  elemental  phosphorus will poison marine fish (causing
skin tissue breakdown and discoloration).   Also,  phosphorus  is
capable  of  being concentrated and will accumulate in organs and
soft tissues.  Experiments  have  shown  that  marine  fish  will
concentrate phosphorus from water containing as little as 1 ug/1.

Fluorides

As  the  most reactive non-metal, fluorine is never found free in
nature but as a constituent of  fluorite  or  fluorspar,  calcium
fluoride,  in  sedimentary  rocks  and  also  of cryolite,  sodium
aluminum fluoride, in igneous rocks.  Owing to their origin  only
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in certain types of rocks and only in a few regions, fluorides in
high  concentrations  are  not  a  common  constituent of natural
surface waters, but they may occur in detrimental  concentrations
in ground waters.

Fluorides  are  used  as  insecticides,  for disinfecting brewery
apparatus, as a flux in the manufacture of steel, for  preserving
wood  and mucilages, for the manufacture of glass and enamels, in
chemical industries, for water treatment, and for other uses.

Fluorides in sufficient quantity are toxic to humans, with  doses
of 250 to 450 mg giving severe symptoms or causing death.

There  are  numerous articles describing the effects of fluoride-
bearing waters on dental enamel of children; these  studies  lead
to  the generalization that water containing less than 0.9 to 1.0
mg/1 of fluoride will seldom cause mottled  enamel  in  children,
and  for  adults,  concentrations  less  than 3 or 4 mg/1 are not
likely  to  cause  endemic  cumulative  fluorosis  and   skeletal
effects.   Abundant  literature  is also available describing the
advantages of maintaining 0.8 to 1.5  mg/1  of  fluoride  ion  in
drinking   water  to  aid  in  the  reduction  of  dental  decay,
especially among children.

Chronic fluoride poisoning of  livestock  has  been  observed  in
areas   where   water   contained   10   to   15  mg/1  fluoride.
Concentrations of 30 - 50 mg/1 of fluoride in the total ration of
dairy cows is considered the upper  safe  limit.   Fluoride  from
waters  apparently  does  not  accumulate  in  soft  tissue  to a
significant degree and it is transferred to a very  small  extent
into  the  milk and to a somewhat greater degree into eggs.  Data
for fresh water indicate that fluorides  are  toxic  to  fish  at
concentrations higher than 1.5 mg/1.

EH» Acidity and Alkalinity

Acidity and alkalinity are reciprocal terms.  Acidity is produced
by  substances  that  yield  hydrogen  ions  upon  hydrolysis and
alkalinity is produced by substances that  yield  hydroxyl  ions.
The  terms  "total acidity" and "total alkalinity" are often used
to express the buffering capacity  of  a  solution.   Acidity  in
natural waters is caused by carbon dioxide, mineral acids, weakly
dissociated  acids, and the salts of strong acids and weak bases.
Alkalinity is caused by strong bases  and  the  salts  of  strong
alkalies and weak acids.

The  term  pH is a logarithmic expression of the concentration of
hydrogen ions.  At a pH of  7,  the  hydrogen  and  hydroxyl  ion
concentrations  are  essentially  equal and the water is neutral.
Lower pH values indicate acidity  while  higher  values  indicate
alkalinity.    The   relationship   between  pH  and  acidity  or
alkalinity is not necessarily linear or direct.

Waters  with  a  pH  below  6.0  are  corrosive  to  water  works
structures,  distribution  lines, and household plumbing fixtures
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and can thus add such constituents to  drinking  water  as  iron,
copper,  zinc,  cadmium and lead.  The hydrogen ion concentration
can affect the "taste" of the water.   At a low  pH  water  tastes
"sour".   The  bactericidal effect of chlorine is weakened as the
pH increases, and it is advantageous to keep the pH close  to  7.
This is very significant for providing safe drinking water.

Extremes of pH or rapid pH changes can exert stress conditions or
kill  aquatic life outright.  Dead fish, associated algal blooms,
and foul stenches are  aesthetic  liabilities  of  any  waterway.
Even moderate changes from "acceptable" criteria limits of pH are
deleterious  to  some  species.   The relative toxicity to aquatic
life of many materials is increased by changes in the  water  pH.
Metalocyanide  complexes can increase a thousand-fold in toxicity
with a drop of 1.5 pH units.  The availability of  many  nutrient
substances  varies  with  the alkalinity and acidity.  Ammonia is
more lethal with a higher pH.

The lacrimal fluid of the human eye has a pH of approximately 7.0
and a deviation of 0.1 pH unit from the norm may  result  in  eye
irritation  for  the  swimmer.  Appreciable irritation will cause
severe pain.

Total Suspended Solids

Suspended solids include both organic  and  inorganic  materials.
The  inorganic  components  include  sand,  silt,  and clay.  The
organic fraction includes such materials  as  grease,  oil,  tar,
animal  and  vegetable  fats,  various fibers, sawdust, hair, and
various materials from  sewers.    These  solids  may  settle  out
rapidly  and  bottom deposits are often a mixture of both organic
and  inorganic  solids.   They  adversely  affect  fisheries   by
covering  the  bottom  of  the  stream  or lake with a blanket of
material that destroys the fish-food bottom fauna or the spawning
ground  of  fish.   Deposits  containing  organic  materials  may
deplete  bottom  oxygen  supplies  and  produce hydrogen sulfide,
carbon dioxide, methane, and other noxious gases.

In raw  water  sources  for  domestic  use,  state  and  regional
agencies generally specify that suspended solids in streams shall
not be present in sufficient concentration to be objectionable or
to  interfere  with normal treatment processes.  Suspended solids
in water may interfere with many industrial processes, and  cause
foaming  in  boilers,  or  encrustations  on equipment exposed to
water, especially as the temperature rises.  Suspended solids are
undesirable in water for  textile  industries;  paper  and  pulp;
beverages;   dairy   products;  laundries;  dyeing;  photography;
cooling systems, and  power  plants.   Suspended  particles  also
serve   as   a  transport  mechanism  for  pesticides  and  other
substances which are readily sorbed into or onto clay particles.

Solids may be suspended in water for a time, and then  settle  to
the   bed  of  the  stream  or  lake.   These  settleable  solids
discharged with man's wastes may be inert,  slowly  biodegradable
materials,   or   rapidly   decomposable  substances.   While  in
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suspension, they increase the  turbidity  of  the  water,  reduce
light  penetration  and  impair  the  photosynthetic  activity of
aquatic plants.

Solids in suspension are aesthetically  displeasing.   When  they
settle  to  form  sludge deposits on the stream or lake bed, they
are often much more damaging to  the  life  in  water,  and  they
retain  the  capacity  to  displease  the  senses.   Solids, when
transformed to sludge deposits, may  do  a  variety  of  damaging
things,  including  blanketing the stream or lake bed and thereby
destroying the living spaces for  those  benthic  organisms  that
would  otherwise  occupy  the  habitat.   When  of an organic and
therefore decomposable nature, solids use a portion or all of the
dissolved oxygen available in the area.  Organic  materials  also
serve  as  a  seemingly inexhaustible food source for sludgeworms
and associated organisms.

Turbidity  is  principally  a  measure  of  the  light  absorbing
properties  of  suspended  solids.   It  is  frequently used as a
substitute method  of  quickly  estimating  the  total  suspended
solids when the concentration is relatively low.

Ammonia and Nitrate Nitrogen

Ammonia  is  a  common  product  of  the decomposition of organic
matter.  Dead and decaying animals and plants  along  with  human
and  animal  body wastes account for much of the ammonia entering
the aquatic ecosystem.  Ammonia exists in  its  non-ionized  form
only  at  higher  pH  levels and is the most toxic in this state.
The lower the pH, the more ionized  ammonia  is  formed  and  its
toxicity  decreases.   Ammonia,  in  the  presence  of  dissolved
oxygen, is converted to nitrate   (NO.3)  by  nitrifying  bacteria.
Nitrite  (NO2) ,  which is an intermediate product between ammonia
and nitrate, sometimes occurs in quantity when  depressed  oxygen
conditions  permit.   Ammonia can exist in several other chemical
combinations including ammonium chloride and other salts.

Nitrates are considered to be among the poisonous ingredients  of
mineralized  waters,  with potassium nitrate being more poisonous
than sodium nitrate.  Excess nitrates  cause  irritation  of  the
mucous linings of the gastrointestinal tract and the bladder; the
symptoms  are  diarrhea  and  diuresis, and drinking one liter of
water containing 500 mg/1 of nitrate can cause such symptoms.

Infant methemoglobinemia,  a  disease  characterized  by  certain
specific  blood  changes  and  cyanosis,  may  be  caused by high
nitrate concentrations in the water used  for  preparing  feeding
formulae.    While  it  is  still  impossible  to  state  precise
concentration limits, it has been widely recommended  that  water
containing  more  than 10 mg/1 of nitrate nitrogen  (NO3.-N)  should
not  be  used  for  infants.   Nitrates  are  also   harmful   in
fermentation processes and can cause disagreeable tastes in beer.
In  most  natural  water  the pH range is such that ammonium ions
(NH^*+)  predominate.    In   alkaline   waters,   however,    high
concentrations  of  un-ionized  ammonia in undissociated ammonium
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hydroxide increase the toxicity of ammonia solutions.  In streams
polluted with sewage, up to one  half  of  the  nitrogen  in  the
sewage  may  be in the form of free ammonia, and sewage may carry
up to 35 mg/1 of total nitrogen.  It has been  shown  that  at  a
level  of  1.0 mg/1 un-ionized ammonia, the ability of hemoglobin
to combine with  oxygen  is  impaired  and  fish  may  suffocate.
Evidence  indicates  that  ammonia  exerts  a  considerable toxic
effect on all aquatic life within a range of less than  1.0  mg/1
to  25  mg/1,  depending  on  the  pH  and dissolved oxygen level
present.

Ammonia can add to the problem  of  eutrophication  by  supplying
nitrogen  through  its  breakdown products.  Some lakes in warmer
climates, and others that are aging quickly are sometimes limited
by the nitrogen available.  Any increase will speed up the  plant
growth and decay process.

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.

Dissolved Solids

In   natural  waters  the  dissolved  solids  consist  mainly  of
carbonates,  chlorides,  sulfates,   phosphates,   and   possibly
nitrates  of  calcium,  magnesium,  sodium,  and  potassium, with
traces of iron, manganese and other substances.

Many communities in the United States and in other countries  use
water  supplies  containing 2000 to 4000 mg/1 of dissolved salts,
when  no  better  water  is  available.   Such  waters  are   not
palatable,  may not quench thirst, and may have a laxative action
on new users.  Waters containing more than  UOOO  mg/1  of  total
salts  are  generally considered unfit for human use, although in
hot climates such higher salt  concentrations  can  be  tolerated
whereas   they  could  not  be  in  temperate  climates.   Waters
containing 5000 mg/1 or more are reported to be bitter and act as
bladder and intestinal irritants.  It is  generally  agreed  that
the salt concentration of good, palatable water should not exceed
500 mg/1.

Limiting  concentrations of dissolved solids for fresh-water fish
may range from 5,000 to 10,000 mg/1,  according  to  species  and
prior  acclimatization.   Some fish are adapted to living in more
saline waters, and a few species of fresh-water forms  have  been
found  in  natural  waters with a salt concentration of 15,000 to
20,000 mg/1.  Fish  can  slowly  become  acclimatized  to  higher
salinities,  but  fish  in  waters of low salinity cannot survive
sudden exposure to high salinities, such as those resulting  from


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discharges  of  oil-well  brines.  Dissolved solids may influence
the toxicity of heavy metals and organic compounds  to  fish  and
other  aquatic life, primarily because of the antagonistic effect
of hardness on metals.

Waters with total dissolved solids over 500 mg/1 have  decreasing
utility  as  irrigation water.  At 5,000 mg/1 water has little or
no value for irrigation.

Dissolved solids  in  industrial  waters  can  cause  foaming  in
boilers  and cause interference with cleaness, color, or taste of
many finished products.  High contents of dissolved  solids  also
tend to accelerate corrosion.

Specific  conductance  is  a  measure of the capacity of water to
convey an electric current.  This  property  is  related  to  the
total  concentration  of  ionized  substances  in water and water
temperature.  This property is frequently used  as  a  substitute
method of quickly estimating the dissolved solids concentration.

Temperature

Temperature  is  one  of the most important and influential water
quality characteristics.  Temperature  determines  those  species
that  may  be  present;  it  activates  the  hatching  of  young,
regulates their activity,  and  stimulates  or  suppresses  their
growth  and development; it attracts, and may kill when the water
becomes too hot or becomes chilled too  suddenly.   Colder  water
generally   suppresses   development.    Warmer  water  generally
accelerates activity and may be a primary cause of aquatic  plant
nuisances when other environmental factors are suitable.

Temperature  is a prime regulator of natural processes within the
water  environment.   It  governs  physiological   functions   in
organisms  and, acting directly or indirectly in combination with
other water quality constituents, it affects  aquatic  life  with
each  change.   These  effects  include  chemical reaction rates,
enzymatic functions, molecular movements, and molecular exchanges
between membranes within and between  the  physiological  systems
and the organs of an animal.

Chemical  reaction  rates  vary  with  temperature  and generally
increase as the temperature  is  increased.   The  solubility  of
gases  in  water  varies  with  temperature.  Dissolved oxygen is
decreased by the decay  or  decomposition  of  dissolved  organic
substances and the decay rate increases as the temperature of the
water  increases  reaching  a  maximum at about 30°C (86°F).  The
temperature of stream water, even during  summer,  is  below  the
optimum  for pollution-associated bacteria.  Increasing the water
temperature increases the bacterial multiplication rate when  the
environment is favorable and the food supply is abundant.

Reproduction  cycles  may  be  changed significantly by increased
temperature because this function takes  place  under  restricted
temperature  ranges.   Spawning  may  not  occur  at  all because


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temperatures are too high.  Thus, a fish population may exist  in
a  heated  area  only by continued immigration.   Disregarding the
decreased reproductive potential,  water  temperatures  need  not
reach  lethal  levels  to  decimate a species.   Temperatures that
favor competitors, predators, parasites, and disease can  destroy
a species at levels far below those that are lethal.

Fish  food  organisms  are  altered  severely  when  temperatures
approach or  exceed  90°F.   Predominant  algal   species  change,
primary  production is decreased, and bottom associated organisms
may  be  depleted  or  altered   drastically   in   numbers   and
distribution.   Increased  water  temperatures   may cause aquatic
plant nuisances when other environmental factors are favorable.

Synergistic actions of pollutants are more severe at higher water
temperatures.  Given amounts of domestic sewage, refinery wastes,
oils,  tars,  insecticides,  detergents,  and  fertilizers   more
rapidly  deplete  oxygen in water at higher temperatures, and the
respective toxicities are likewise increased.

When water temperatures increase, the predominant  algal  species
may  change  from  diatoms  to  green  algae, and finally at high
temperatures to blue-green algae, because of species  temperature
preferentials.  Blue-green algae can cause serious odor problems.
The  number  and  distribution  of benthic organisms decreases as
water temperatures increase above 90°F, which  is  close  to  the
tolerance  limit for the population.  This could seriously affect
certain fish that depend on benthinc organisms  as a food source.

The cost of fish being attracted to heated water in winter months
may be considerable, due to fish mortalities that may result when
the fish return to the cooler water.

Rising  temperatures  stimulate  the  decomposition  of   sludge,
formation  of  sludge gas, multiplication of saprophytic bacteria
and fungi  (particularly in the presence of organic  wastes),  and
the   consumption  of  oxygen  by  putrefactive  processes,  thus
affecting the esthetic value of a water course.

In general, marine water temperatures do not change as rapidly or
range as widely as those of freshwaters.   Marine  and  estuarine
fishes,  therefore,  are  less tolerant of temperature variation.
Although this limited tolerance is greater in estuarine  than  in
open water marine species, temperature changes  are more important
to  those  fishes  in  estuaries  and  bays than to those in open
marine areas, because of the nursery and replenishment  functions
of  the  estuary  that  can  be  adversely  affected  by  extreme
temperature changes.

Cadmium

Cadmium in drinking water  supplies  is  extremely  hazardous  to
humans,  and  conventional  treatment, as practiced in the United
States, does not remove it.  Cadmium is cumulative in the  liver,
kidney,  pancreas,  and  thyroid  of humans and other animals.  A


                                    88

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severe bone and kidney syndrome in Japan has been associated with
the ingestion of as little as 600 ug/day of cadmium.

Cadmium is an extremely dangerous  cumulative  toxicant,  causing
insidious  progressive  chronic  poisoning  in mammals, fish, and
probably  other  animals  because  the  metal  is  not  excreted.
Cadmium   could  form  organic  compounds  which  might  lead  to
mutagenic or teratogenic  effects.   Cadmium  is  known  to  have
marked acute and chronic effects on aquatic organisms also.

Cadmium  acts synergistically with other metals,  copper and zinc
substantially increase its toxicity.  Cadmium is concentrated  by
marine organisms, particularly molluscs, which accumulate cadmium
in calcareous tissues and in the viscera.  A concentration factor
of  1000  for  cadmium  in fish muscle has been reported, as have
concentration factors of 3000 in marine plants, and up to  29,600
in  certain  marine  animals.   The  eggs  and larvae of fish are
apparently  more  sensitive  than  adult  fish  to  poisoning  by
cadmium,  and  crustaceans  appear to be more sensitive than fish
eggs and larvae.

Chromium

Chromium, in its various valence states, is hazardous to man.  It
can  produce  lung  tumors  when   inhaled   and   induces   skin
sensitizations.   Large doses of chromates have corrosive effects
on the  intestinal  tract  and  can  cause  inflammation  of  the
kidneys.   Levels  of  chr ornate  ions  that have no effect on man
appear to be so low as to prohibit determination to date.

The toxicity of chromium salts toward aquatic life varies  widely
with  the  species, temperature, pH, valence of the chromium, and
synergistic or antagonistic effects, especially that of hardness.
Fish are relatively tolerant of chromium  salts,  but  fish  food
organisms  and  other  lower  forms of aquatic life are extremely
sensitive.  Chromium also inhibits the growth of algae.

In some agricultural crops, chromium can cause reduced growth  or
death  of  the  crop.   Adverse  effects of low concentrations of
chromium on corn, tobacco and sugar beets have been documented.
Occurring abundantly in rocks and ores, zinc is  readily  refined
into a stable pure metal and is used extensively for galvanizing,
in  alloys, for electrical purposes, in printing plates, for dye-
manufacture  and  for  dyeing  processes,  and  for  many   other
industrial  purposes.   Zinc  salts  are  used in paint pigments,
cosmetics,  Pharmaceuticals,  dyes,   insecticides,   and   other
products too numerous to list herein.  Many of these salts (e.g.,
zinc  chloride  and  zinc  sulfate)  are highly soluble in water;
hence it is  to  be  expected  that  zinc  might  occur  in  many
industrial  wastes.   On  the  other  hand, some zinc salts (zinc
carbonate, zinc oxide, zinc sulfide) are insoluble in  water  and
                                    89

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consequently it is to be expected that some zinc will precipitate
and be removed readily in most natural waters.

In   zinc-mining   areas,  zinc  has  been  found  in  waters  in
concentrations as high as 50 mg/1 and in  effluents  from  metal-
plating  works  and  small-arms ammunition plants it may occur in
significant concentrations.  In most surface and  ground  waters,
it is present only in trace amounts.  There is some evidence that
zinc   ions  are  adsorbed  strongly  and  permanently  on  silt,
resulting in inactivation of the zinc.

Concentrations of zinc in excess of 5 mg/1 in raw water used  for
drinking water supplies cause an undesirable taste which persists
through  conventional treatment.  Zinc can have an adverse effect
on man and animals at high concentrations.

In soft water, concentrations of zinc ranging  from  0.1  to  1.0
mg/1 have been reported to be lethal to fish.  Zinc is thought to
exert  its  toxic  action by forming insoluble compounds with the
mucous that covers the gills, by damage to the  gill  epithelium,
or  possibly by acting as an internal poison.  The sensitivity of
fish to zinc varies with species, age and condition, as  well  as
with  the  physical  and  chemical  characteristics of the water.
Some acclimatization to the presence of zinc is possible.  It has
also been observed that the effects of  zinc  poisoning  may  not
become  apparent  immediately,  so  that  fish removed from zinc-
contaminated to zinc-free water  (after 4-6 hours of  exposure  to
zinc)  may  die  U8 hours later.  The presence of copper in water
may increase the toxicity of zinc to aquatic organisms,  but  the
presence  of  calcium  or  hardness  may  decrease  the  relative
toxicity.

Observed values for the distribution of zinc in ocean waters vary
widely.  The major concern with zinc compounds in  marine  waters
is  not  one  of acute toxicity, but rather of the long-term sub-
lethal effects of the metallic compounds and complexes.  From  an
acute toxicity point of view, invertebrate marine animals seem to
be  the  most  sensitive organisms tested.  The growth of the sea
urchin, for example, has been retarded by as little as 30 ug/1 of
zinc.

Zinc sulfate has also been found to be lethal to many plants, and
it could impair agricultural uses.

Vanadium

Metallic vanadium does not occur free  in  nature,  but  minerals
containing  vanadium  are  widespread.  Vanadium is found in many
soils and occurs in vegetation grown  in  such  soils.   Vanadium
adversely  effects  some  plants  in  concentrations as low as 10
mg/1.

Vanadium as calcium vanadate can inhibit the growth of chicks and
in  combination  with  selenium,  increases  mortality  in  rats.
                                  90

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Vanadium  appears  to  inhibit  the  synthesis of cholesterol and
accelerate its catabolism in rabbits.

Vanadium causes death to occur in  fish  at  low  concentrations.
The  amount needed for lethality depends on the alkalinity of the
water and the specific vanadium  compound  present.   The  common
bluegill can be killed by about 6 ppm in soft water and 55 ppm in
hard  water  when  the vanadium is expressed as vanadryl sulfate.
Other fish are similarly affected.

Specific conductance is a measure of the  capacity  of  water  to
convey  an  electric  current.   This  property is related to the
total concentration of ionized  substances  in  water  and  water
temperature.   This  property  is frequently used as a substitute
method of quickly estimating the dissolved solids concentration.

Arsenic

Arsenic is found to a small extent in  nature  in  the  elemental
form.   It occurs mostly in the form of arsenites of metals or as
pyrites.

Arsenic is normally present in sea water at concentrations  of  2
to  3  ug/1  and  tends  to  be  accumulated by oysters and other
shellfish.  Concentrations of 100 mg/kg  have  been  reported  in
certain shellfish.  Arsenic is a cumulative poison with long-term
chronic  effects  on  both  aquatic  organisms  and  on mammalian
species and a succession of small doses may add  up  to  a  final
lethal  dose.   It is moderately toxic to plants and highly toxic
to animals especially as AsH3.

Arsenic trioxide, which also is exceedingly toxic, was studied in
concentrations of 1.96 to 40 mg/1 and found to be harmful in that
range to fish and other aquatic life.   Work  by  the  Washington
Department  of Fisheries on pink salmon has shown that at a level
of 5.3 mg/1 of As2CX3 for 8 days was  extremely  harmful  to  this
species;  on  mussels,  a  level of 16 mg/1 was lethal in 3 to 16
days.

Severe human poisoning can result from 100 mg concentrations, and
130 mg has proved fatal.  Arsenic  can  accumulate  in  the  body
faster  than  it  is excreted and can build to toxic levels, from
small amounts taken  periodically  through  lung  and  intestinal
walls from the air, water and food.

Arsenic   is   a   normal   constituent   of   most  soils,  with
concentrations ranging  up  to  500  mg/kg.   Although  very  low
concentrations  of arsenates may actually stimulate plant growth,
the presence of excessive soluble arsenic  in  irrigation  waters
will  reduce  the yield of crops, the main effect appearing to be
the destruction of chlorophyll in the foliage.  Plants  grown  in
water   containing   one  mg/1  of  arsenic  trioxides  showed  a
blackening of the vascular bundles  in  the  leaves.   Beans  and
cucumbers are very sensitive, while turnips, cereals, and grasses
are  relatively  resistant,  old orchard soils in Washington that
                                   91

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contained 4 to 12 mg/kg of arsenic trioxide in the top soil  were
found to have become unproductive.

Radioactivity

Ionizing  radiation, when absorbed in living tissue in quantities
substantially  above  that  of  natural  background  levels,   is
recognized  as injurious.  It is necessary* therefore, to prevent
excessive levels of radiation from reaching any  living  organism
humans,  fishes, and invertebrates.  Beyond the obvious fact that
radioactive wastes emit ionizing radiation, they are also similar
in many respects to other chemical wastes.   Man's  senses  cannot
detect radiation unless it is present in massive amounts.

Plants  and  animals, to be of any significance in the cycling of
radionuclides in the aquatic  environment,   must  accumulate  the
radionuclide,  retain  it,  be  eaten by another organism, and be
digestible.  However, even if an organism accumulates and retains
a radionuclide and is not eaten before it dies, the  radionuclide
will   enter   the  "biological  cycle"  through  organisms  that
decompose  the  dead  organic   material   into   its   elemental
components.   Plants  and animals that become radioactive in this
biological cycle can thus pose a health hazard when eaten by man.

Aquatic life may receive radiation from radionuclides present  in
the  water  and  substrate  and  also from radionuclides that may
accumulate   within   their   tissues.    Humans   can    acquire
radionuclides  through  many  different pathways.  Among the most
important are through drinking  contaminated  water,  and  eating
fish  and  shellfish  that  have  concentrated  nuclides from the
water.  Where fish or other fresh or marine  products  that  have
accumulated radioactive materials are used as food by humans, the
concentrations  of  the  nuclides  in  the  water must be further
restricted, to provide assurance that the total intake of  radio-
nuclides from all sources will not exceed the recommended levels.

In order to prevent unacceptable doses of radiation from reaching
humans,  fish,  and other important organisms, the concentrations
of radionuclides  in  water,  both  fresh  and  marine,  must  be
restricted.
Radium-226  is  one  of  the  most hazardous radioisotopes of the
uranium decay scheme, when present  in  water.    The  human  body
preferentially utilizes radium in lieu of calcium when present in
food or drink.  Plants and animals concentrate  radium, leading to
a multiplier effect up the food web.

Radium-226 decays by alpha emission into radon-222, a radioactive
gas  with  a half life of 3.8 days.  The decay  products of radon-
222, in  turn,  are  particulates  which  can  be  adsorbed  onto
respirable  particles  of dust.  Radon and its  decay products has
been implicated in an increased incidence of lung cancer in those
workers exposed to high levels (Bureau of Mines, 1971) .   Heating
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or  grinding of phsophate rock would liberate radon and its decay
products to the surrounding atmosphere.

It is generally agreed that unlilke other materials, there is  no
threshold value for radiation exposure.  Accordingly, the Federal
Radiation  Council  has  repeatedly stated that all radiochemical
material releases are to  be  kept  to  the  minimum  practicably
obtainable.  The council states "It should be general practice to
reduce  exposure  to  radiaiton,  and  positive efforts should be
carried out to fulfill the sense of these recommendations.  It is
basic that exposure  to  radiation  should  result  from  a  real
determination   of  its  necessity  (Federal  Radiation  Council,
1960)."

Oil and Grease

Oil and grease exhibit  an  oxygen  demand.   Oil  emulsions  may
adhere  to  the  gills of fish or coat and destroy algae or other
plankton.  Deposition of oil in the bottom sediments can serve to
exhibit normal benthic growths,  thus  interrupting  the  aquatic
food chain.  Soluble and emulsified material ingested by fish may
taint the flavor of the fish flesh.  Water soluble components may
exert  toxic  action  on  fish.   Floating oil may reduce the re-
aeration of the water surface and in conjunction with  emulsified
oil   may   interfere   with   photosynthesis.   Water  insoluble
components damage the plumage and  costs  of  water  animals  and
fowls.   Oil and grease in a water can result in the formation of
objectionable  surface  slicks  preventing  the  full   aesthetic
enjoyment of the water.

Oil  spills  can  damage the surface of boats and can destroy the
aesthetic characteristics of beaches and shorelines.

Nickel

Elemental nickel seldom occurs in nature,  but  nickel  compounds
are found in many ores and minerals.  As a pure metal it is not a
problem  in  water  pollution  because  it is not affected by, or
soluble in,  water.   Many  nickel  salts,  however,  are  highly
soluble in water.

Nickel  is extremely toxic to citrus plants.  It is found in many
soils in California, generally in insoluble form,  but  excessive
acidification  of such soil may render it soluble, causing severe
injury to or the death of plants.  Many experiments  with  plants
in solution cultures have shown that nickel at 0.5 to 1.0 mg/1 is
inhibitory to growth.

Nickel  salts can kill fish at very low concentrations.  Data for
the fathead minnow show death occurring in the range of 5-43  mg,
depending on the alkalinity of the water.

Nickel is present in coastal and open ocean concentrations in the
range  of 0.1 - 6.0 ug/1, although the most common values are 2 -
3 ug/1.  Marine animals contain up to 400 ug/1, and marine plants
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contain up to 3,000 ug/1.  The lethal limit  of  nickel  to  some
marine  fish has been reported as low as 0.8 ppm.  Concentrations
of 13.1 mg/1 have been reported to cause a 50  percent  reduction
of  the  photosynthetic  activity  in the giant kelp (Macrpcystis
pyrif era)  in 96 hours, and a low concentration was found to  kill
oyster eggs.

METHODS OF ANALYSIS

The methods of analysis to be used for quantitative determination
are  given  in  the Federal Register 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 the Examination of Water  and  Waste  Water  (SMWW)  (ref  W)
method 215.   ~

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

Vanadium should be determined by SMWW method 164.
                                    94

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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 minimize the majority of
those  which  are  particularly  detrimental  to  natural   water
receiving  bodies.   Much  of  this  work  has  been  directed at
correcting the source  of  the  contamination  or  an  in-process
improvement  rather  than  an  end-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 or 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 including that available by
     transfer from other industries

    -    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.
                                    95

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Sulfuric Acid Plant Effluent 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  removal.   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 impuri-
ties discharged vary widely with the raw water quality.

An inherent hazard of any liquid handling process is  the  occur-
rence 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 instal-
lation 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  21  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 cut-
off 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 pK to 6 is required.  Neutralization
is preferably by use of lime.  Lime serves not only to neutralize
                                   96

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      SULFURIC ACID
      PROCESS PLANT
                                                 TO EFFLUENT DISPOSAL
                                                             /  ,	TO GYPSUM POND
                                                            ( _!._  (ALTERNATE)		
                                                                —      CONTROLLED DISCHARGE RETENTION
                                                                                     POND
                                                                SITE VARIES WITH AREA AVAILABLE AND PLANT SIZE
                                                                               (SIZE MIGHT BE 300' x 30' x 6'
                                                     MAY BE BLOCKED/DAMMED
                                                     TO PERMIT POND WATER PH
                                                     CONTROL IF REQUIRED
                                                                                I EXCHANGER
                                   FROM 4th CONVERTER
                                                       TO ATMOSPHERE
                                                                                 FROM HT.
                                                                                 EXCHANGER
                                                                                   A
                                                                                    I
                                                                                    I
                                 CLARIFIED WATER
CLARIFIED WATER
                                                             TO PUMP
                                                             TANK -4
                                                                                                 COOLING
                                                                                                  TOWER
                COOLING
                 TONER
               SLOWDOWN
                        TO PUMP
                        TANK
NOTE-
CIRCLED ITEMS ADDED
FOR EFFLUENT CONTROL
                                                    FIGURE  19
         SULFURIC ACID EFFLUENT CONTROL
NOTE: THIS APPLIES TO BOTH
SINGLE AND DOUBLE
ABSORPTION PLANTS

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the  hydrogen ion concentration  (low pH) but also removes  sulfate
(SO*t) as an insoluble calcium sulfate according to the   following
reaction:

       H2SO£ +     CaO +         H20  —> CaSO4    »2H20

     Sulfuric      Lime       Water      Calcium Sulfate
      Acid
                                    98

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Gypsum Pond (Contaminated)  Water Treatment

As   described  in  Section  V,  all  phosphate  complex  process
effluents (contaminated water)  are collected and impounded.   The
impoundment  area,ranging in size from 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  of  the  fluoride  and  phosphate
contaminants.  Fluorides are present in the water principally  as
fluosilicic  acid  with  small amounts of soluble salts as sodium
and potassium fluosilicates and hydrofluoric acid.  Phosphorus is
present principally as phosphoric acid with some minor amounts of
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 +    E2Q  —>  3 CaF2   +  2 H20  + Si02

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
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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 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 H3PO.4    +    CaO
    Phosphoric      Lime
      Acid

    + Ca (H2P04) 2 +    CaO
    Monocalcium     Lime
     Phosphate
                         H2O
                        Water
                         H2O
                        Water
                  Ca(H2P04) 2
                 Monocalcium
                  Phosphate

                  2CaHPO4
                 Dicalcium
                 Phosphate
                  2 H20
                  Water
                  Water

                  2 H20
                  Water
As  before, this mixture is retained in a quiescent area to allow
the CaHPOf* and minor amounts of CaF.2 to settle.

The reduction of the P value is strongly dependent upon the final
pH  level,  holding  time,  and  quality  of  the  neutralization
facilities,  particulary  mixing  efficiency.   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 of liming.
Laboratory and plant data for phosphorus and fluoride removal
presented below:
                                                       is
PH
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
 Phosphorus (mq/1)
laboratory   plant
   500
   330
   200
   120
    20
     3
     1.2
42
24
18
14
12
 8
 6
 3
 1.2
        Fluoride jmg/l\
       laboratory plant
17
14
12.5
12.5
12.5
12.5
12.5
12.5
12.5
13
 8.5
 6.8
 5.8
 5.2
 4.8
 4.6
12.5
Although  the  starting  concentrations  are  either arbitrary or
specific to that plant  only,  the  data  does  show  significant
removal at high pH.

At  plant  008  results  from lime treatment show that phosphorus
concentrations decrease with  time  as  well  as  increasing  pH.
Phosphorus  concentration  vs  pH  with  a 46 hour holding period
were:
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                                  P. STEAM
          TO GYPSUM POND
      FIGURE  20

POND WATER TREATMENT
                                               CALCIUM PHOSPHATE
                                                     POND
TO RIVER OR
PROCESS UNITS

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              £H                 mq/1 P

              5.8                 20
              6.5                  9.1
              8.3                  3.6

The time effect on phosphorus concentration is:

              Time-hours        joH           mg/1 P

                 0              7.85           60
                 5              7.6            29
                22              6.7            19
                H6              6.U             9

Data from three years of double lime  treatment  of  gypsum  pond
effluent  from  plant  008  at  a pH of 5 to 7 shows a phosphorus
concentration (as P) of 10 to UO mg/1.

Radium 226 is also precipitated by  lime  treatment  increasingly
with increasing pH as presented below:

         pH                  Radium 226
                             picocuries/1

         2.0                     91
         1.5                     65
         U.O                      7.6
         8.0-8.5                  O.OU

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 have NH3-N in the
contaminated water system.   "Double  lime"  treatment  will  not
reduce  the  N  quantity, although at high pH  (greater than -9.0) r
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 to 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.
                                   102

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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.
                                   103

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 GYPSUM POND
                           SEEPAGE DITCH
                           RETURN TO GYPSUM
                           POND BY PUMP
                                                          OUTSIDE OF PLANT
GYPSUM POND
   BED        \  \
                  \ x
           SEEPAGE'"'  v\
*— APPROXIMATELY^
   10 FT. WIDE BY
   ABOUT 3 FT. DEEP
.^4^^^^
                                                            Hi
                                                           SURFACE DRAINAGE
                                                           DITCH EXTERNAL TO
                                                           THE PLANT
                                 FIGURE  21
                     GYPSUM POND WATER SEEPAGE CONTROL

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gjnrngrtiyrn[[[rPhosghate self-Contained	Process

It was mentioned in the "double lime" treatment description  that
the  best  means of reducing NH3-N from appearing in the contami-
nated water system was to prevent its entry into the water.  NH3-
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 gypsum
pond water system and can be  either  introduced  back  into  the
process  or  treated  for ammonia removal prior to discharge 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%  P2O5  phosphoric
acid  is  required  to  produce  ammonium  phosphates.  It may be
necessary to increase this concentration to as high as 5H%  P2OJ5.
This  is dependent upon the water quantity to be absorbed and the
acid concentration required  to  produce  the  specific  ammonium
phosphate product.  Figure 22 is a sketch of this procedure.
                                    105

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PUMP
                         CONCENTRATED
                         PHOSPHORIC ACID
       REACTOR
                    TO PROCESS
       FIGURE  22

DAP SELF CONTAINED PROCESS

-------
Wet  Process  Phosghoric  Acid  - Pond JJater Dilution of Sulfuric
Acid

general

The need to treat phosphate fertilizer process contaminated water
is almost entirely dependent upon the local  rainfall/evaporation
ratio.  This means that barring poor water management and concen-
trated  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 5Q% of the
total fresh water intake to a phosphoric acid  plant.   Not  only
does  use of contaminated water for sulfuric acid dilution elimi-
nate (except for extreme weather conditions) water effluent  from
a  phosphate  complex,  but  the  overall  P2O5  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.

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).
                                  107

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                                                                         SLURRY FEED
                                                                           TO FILTER
 POND WATER
    WASH
      i      I
FRESHWATER
   WASH
                         SLURRY TO
                          FILTER
o
Co
                                                                                              FILTER
                                                                                                               TO DISPOSAL
                                                                                                                  AREA
                                                                                                                  A
RECYCLE ACID
 TO REACTOR
                                                                                                           HAND WATER
                                                                                                              SLUICE
                                          CONCENTRATED SULFURiC ACID

                                          POND WATER FOR DILUTION
                                                                    FIGURE  23
                                                       WET PROCESS PHOSPHORIC ACID SYSTEM
                                              POND WATER USE FOR SULFURIC ACID DILUTION TO REACTOR SYSTEM

-------
    FEED STREAM-POND  WATER

CONCENTRATED SULFURIC ACID
        PRODUCT STREAMS
        DILUTED ANDCOOLED
        SULFURIC ACID CONTAINS
        RECOVERED P205
                                                                                                TO POND
                                                 FIGURE
                                         SULFURIC ACID DILUTION WITH
                                                 POND WATER

-------
                CONTROL 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 Stri ppjng

This  treatment  method can be used on process condensate, boiler
blowdown or cooling tower  blowdown  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 of 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 condensate effluent before dis-
charge.   The  concentration of ammonia in the condensate feed to
the stripper varies from 100 mg/1 to 1,300 mg/1 with the stripped
effluent ranging from 5 mg/1 to 100  mg/1  giving  reductions  in
some  cases  of  better  than  95H.  However, the best consistent
results from 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 from water depends on how the ammonia exists
in  the water.  In neutral solutions ammonia exists as NH4- while
at higher pH  (11 to 12)  ammonia exists as dissolved NH3_ gas.  The
following equilibrium prevails:

NHU+     —*•    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
                                   110

-------
the  stripper at a higher temperature  (and pressure) would be the
preferred design method.

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 to 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 (110
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. (Figure 25)

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 HI I/sec (700 gpm)  of
total condensate input.  The effluent from the stripper has  less
than  5 mg/1 ammonia (Fig. 26).  A fourth ammonia 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.

-------
COOLING
WATER IN
   OUT
               TO C02 SYSTEM ~
               HOT CARBONATE SYSTEM'
               TO   ATMOSPHERE
STRIPPER
CONDENSER
           Tj
                      AMMONIA
                      STRIPPER
REBOILER/
STEAM
                  LEVEL
                  CONTROLLED
                  VESSEL~
                                                CONDENSATE
                                     POSSIBLE CAUSTIC
                                     ADDITION
                                     IF DESIRED/REQUIRED
                                                 CONDENSATE
                                                 FEEDTANK
                                              TO COOLING TOWER ~
                                              TOSEWER~
                                              TO BOILERS~
                                              TO RAW WATER
                                                 TREATMENT SYSTEM
                     FIGURE  25
           AMMONIA/CONDENSATE STRIPPING
                            112

-------
                                                                —o
                                                                             OVERHEAD
                                                                             ACCUMULATOR
                                                            STRIPPER
SECOND SHIFT
 CONVERTER
     I
FT
R ^ 	 ^
CONDENSATEFROM ^__
TRAP *"
4 	 :.--,
~~*
r S
AMMONIA
CONDENSATE
STRIPPER
J^EXCHANGERj | ^~y-^
r t i

RETURN TO HP
BOILER
1 r





I—
i
JL
KO
POT
4,br
~


^
^








^ .
•:«•_
L_T

i
Lf^5\ .

KO
	 POT
k^^ CONDENSATE
1 FROMVADHJM
xfxSYSTEM SYNTMFS1S

1 ^--L. ARSORRFR
| | 	 KO
^\ SYNTHESIS
SYNTHESIS GAS FROM jf*-Z, ^"^riJ^^^o
MFTHAJMATflR ^T COMPRESSOR
MtlHAIMAIUH ^ KO
POT
Sr
                                                    SEWER

                                           FIGURE  26

                          INTEGRATED AMMONIA/CONDENSATE STRIPPER UNIT

-------
      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 for 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  absorbers  of  air-borne  ammonia
with the result that their blowdowns may contain up to 50 mg/1 of
ammonia.
                                    114

-------
                              WATER IN
                                i
DISTRIBUTION
   BASIN
              FAN
AIR OUT
AIR IN
                                             'TYPICAL FILL
                                             • BAFFLE (TYPICAL!
                                                        WATER OUT
                    CATCH BASIN
                         FIGURE  27

             AMMONIA/CONDENSATE AIR STRIPPING
                    From Slechta And Gulp 196?
                              115

-------
3.High Pressure Air/Steam Stripping

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 to 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 would 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.
                                   116

-------
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  back  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  (38)  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) of 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  (39,
40).   This  treatment unit has been installed in a urea plant in
the spring of 1973  (Fig. 29).  Although only 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 off and  recovered  in  the
urea synthesis section of the main plant.

h  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.  Data from the
plant with this treatment system including  prill  tower  fallout
show organic nitrogen (as N)  monthly average values as follows:
                                    117

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       kg/kkcr  (lb/1000 Ib)
             0.09
             0.230
             0.205
             0.031
             0.052
             0.087
             0.054
Average      0.115
                 118

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       TO LP CAR BAM ATE
         CONDENSER
A
I
FROM CONDENSERS
     AMMONIA
     WATER TANK
                     FIRST
                    DESORBER
                                    t
                                        HYDROLYZER
                      i	
                     rr
                          	i
                                                          STEAM
                                                                  \     7
                                                    HEAT EXCHANGER
                                                    WASTE WATER
                                                      COOLER
                                      FIGURE  28
                                                                   FT
                                                                      f
                                                   TO SEWER
                                    UREA HYDROLYSIS

-------
                                                                                   TO UREA SYNTHESIS
                                                                                        SECTION
Ni
o
             PROCESS
             CONDENSATE
   HEAT
EXCHANGER
                                                           CONDENSATE
                                                            RECOVERY
                                                             STRIPPER
                                                                                       STEAM
              CONDENSATE
                 TANK

k



^^


1
                          FEED PUMP
                                                                                                  EFFLUENT
                                                          FIGURE   29

                                                       UREA HYDROLYSIS

-------
                            ADDENDUM
                     Urea Manufacturing Data

The information provided by one of the respondants was labeled in
a misleading manner in that a part of the waste water coming from
a  prill  tower operation was identified as shipping and blending
loss.  This led  to  an  incorrect  interpretation  of  the  data
supplied  by  the  respondant,  and  of the data collected by EPA
during the preparation of urea manufacturing limitations.   As  a
result of comments received after the close of the public comment
period,  the  matter  was  further  investigated  and the correct
interpretation discovered.

A special visit was made to  the  exemplary  plant  in  question,
which  had  been  used  as  the  basis  for establishing effluent
limitations, to confirm the  validity  of  the  above  referenced
comment  and  to  collect  additional data.  On the basis of this
investigation it was confirmed that the comment  was  valid.   On
the  basis  of  the  previously  available  data  plus  new  data
collected during this  visit,  a  re-evaluation  of  the  organic
nitrogen  limitations  was  made  resulting  in  a  substantially
increased discharge level for urea manufacturing  based  on  best
practicable  control  technology  currently  available  and  best
available control technology.
The  data  and  re-evaluation  for   best   practicable
technology currently available is summarized as follows:

                            Plant 006

              Monthly Averages for Organic Nitrogen
             (as N} effluent from Urea Manufacturing
                                           control
Primary
Manufacturing
kg/kkg
(lb/1000 Ib)
of product

   0.130
   0.132
   0.204
   0.109
   0.057
   0,098
   0.266
   0.109
   0.070
   0.112
   0.083
   0.095
Prill Tower
Fallout
kg/kkg
lb/1000 Ib)
of product

  0.067
  0.222
  0.165
  0.297
  0.318
  0.121
  0.394
  0.136
  0.502
  0.535
  0.272
  0.051
Total
kg/kkg
(lb/1000 Ib)
of product

  0.197
  0.354
  0.368
  0.415
  0.375
  0.219
  0.660
  0.244
  0.573
  0.644
  0.356
  0.146
Rainfall
 for
Month
inches

 0.70
 1,
 1,
  85
  65
 3.10
 1.20
 1.00
 5.64
 3.35
 4.95
   50
   92
5
1
4.35
Average
   0.123         0.239
Revised Guidelines No,
   0.175
               0.379

               0.500
                2.93
                                    121

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This  data  is  based  on daily analysis sheets supplied by plant
006.

The fallout from the prill tower is collected  in  the  discharge
system  due to seepage and rainfall washing of the area where the
dust falls.  When a month of high rainfall follows a month of low
rainfall, levels of discharge increase to exceed, in some  cases,
the  established  limitation.   This  is  bourne out in the above
data.  Depending on local conditions,  it  may  be  necessary  to
average  a low rainfall month and the following two high rainfall
months to achieve the established limitation.
                                    122

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B:Lg|og4caJ. JtTreatmen-t^-^Nitrification and Denitrification

This possible treatment is  based  on  the  reaction  of  ammonia
nitrogen with oxygen in an aerated pond or basin to form nitrates
via biological oxidation.  The nitrates are in turn reacted in an
anaerobic pond in the presence of a biodegradable carbon compound
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 in a lagoon, pond  or
a trickling filter according to the following equations:

 2NH3  +  302    —*•   2NO2-  +  2H+  +  2H2O

 2NO2-  +  02    —"*"   2N03-

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.  The initial breakdown of  the  nitrates  requires  that
organic  carbon  be present.  This can be in the form of methanol
in which case the following overall reaction would occur:

 6NO3-  *  5CH3OH  —^  3N2 + 5CO2 + 1H2Q + 6OH~

Thie 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.  methanol)
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.
                                   123

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                             AERATION PUMPS
WASTE WATER INFLUENT
                                                                                                           TO
                                                                                                         OUTFALL
                                 NITRIFICATION
                                                             LIFT STATION
                                                   FIGURE  30
                                             BIOLOGICAL TREATMENT

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   ^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 anion unit or both, this
depends on the nature of the ions to be removed  from  the  waste
water.

1. cation/toioni:jSegaration^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  ammonium  ions  and
nitrate  ions  (Eig. 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+ ion combines with the nitrate ion to form
nitric acid.

 NH4N03  +  R2H+  —*• R2NH«  +  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 formed.

 HNO3  +  R2OH  —>  R2NO3  +  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 tower 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  on  available
fertilizer products on site, this by-product may be used as is or
it may be concentrated for sale.

h  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 for 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. Se 1 ective Ion Exchange for Ammonia Removal
                                    125

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                                  FROM PLANT POND
NITRIC ACID
              TANK
fT"
 PRODUCT
AMMONIUM
 NITRATE
                 *  N
                                      DEMINERLIZER
                                      —  WATER
                                                                           AMMONIA
                                  FIGURE  31
                                  ION EXCHANGE

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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 (U3)   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 remove  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.

04 Jr^
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 be 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 Hitr ate 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
ammonia 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.
                                    127

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                                                                  INCOMING OIL/GREASE
NJ
CD
         OIL/GREASE BEARING
           STREAM
         FROM PLANT
                        SUMP OR TANK
SAWAGED
OIL/GREASE
                                                   CLEAR WATER
                                                      EXIT
                                                                                         OIL/GREASE
MECHANICAL SKIMMER
TO         REMOVAL
AREA
                                                                                 POND OR SUMP
                                                                                                                CLEAR WATER
                                                                                                                   EXIT
                                                             FIGURE  32
                                                     OIL/GREASE  REMOVAL SYSTEMS

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                                                                             I	^ TAILGAS
NITRIC ACID
 AMMONIA
TO VENT SCRUBBER
i
1
i_
COND
r*
I
i
1
»ir
REACTOR

4 	 ' " COOLING WATER
ENSER
-inn. nfr COOLING WATER
CONDENSED
WATER
PROCESS
RECYCLE
	 -' ^ TO CONCENT RA1

POR—i
SURGE
TANK
-e
MAKE-UP ACID
NITRIC ACID
A
[OR
GAS FROM CONVERTER 	 _fc
AND HEAT EXCHANGERS ""^

r i
3SORPTIC
COLUMN
C

t

c

N

1,',"^" 	 f, WATFR


.,_,,~_^ TRAYS
PRODUCT
^ NITRIC ACID
            AMMONIUM NITRATE PLANT
                                                                       NITRIC ACID PLANT
                                          FIG01E  33
                          AMMONIUM NITRATE EFFLUENT UTILIZATION

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Page Intentionally Blank

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                          SECTION VIII
            COST, ENERGY ANDNON-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  other  to  meet  more  advance
    levels of control.

HaterjiitEffluentcTreatment^Co9t .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.

In terestgn
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 of 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.
                                    131

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Ogerating_and	Maintenance Cogts

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 maintenance, 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.

Eg fluent_Quality

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 flow 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 of 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.

Installationand 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  construc-
tion.

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
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Phosphat e_ Subcateggry  (Table 2)

Sulfuric Acid Effluent Control

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

It should be possible to arrange for this work to be accomplished
and put into service with no 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_ifaterjTreatrnent

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.

jypsum Pond Water Seepage control

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

instruction time is considered the prime requirement here.   The
fork  around  a 80-100 hectare  (200-250 acre) pond area should be
.ccomplished in ten weeks.   It  is  not  anticipated  that  much
tart-*up  -time  will  be consumed to start the pumps, so time for
 his effort will not be considered.
                                   133

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                                                                                                              TREBLE 2
                                                                                                        fao&HKm SBOUEOaiBf
JUWUftU i JSgf&UEHT QURLFIY
*<^^atihg * felntespnQe
Wafer to figure I *lnteiest On. Costs {Sxplaairag Bwergy *Emsxg¥ and *!flofeal Afinual
TBS3GMNT jy^EEKSECVE ftn: ftefer^toe *InwstraSit ^^^f *Deptreeiatian aid PoMSrt Power Costa CtStS
B SaJ.£urie JkaLd $ •$ $ 5 $ $
EffltMit Control IS 232,760 17,470 23,280 9,310 5,000 S5.060
B Etm Water Treating 20 349,600 26,220 34,960 13,990 SO-.05/1QOQ 90!
treated
C Qapsun Pond lfe£fir 21 163,680 12,375 16,370 6,550 5fOOO 40,295
Seepage OczitmL
C Additimal LlBKtng
C We Self Oonkaina 22 312,800 23,468 3I,2fl» S8rSlQ 344,650 457,900
i*£0aess
D Bami Wbtec Uaei Fa 23 310,9S) 23,320 31,000 1Z^40 16S.SOO 235,260
SuUEtnrlc Acid
DUUddon to Baifctar
D POifl HEfefar Iteed Rr 23 110,400 B,280 11,040 4,420 168,500 192, 240
Sulforie Add
Biluticn to B&ae&or
D Sulfniie Add Diliition 24 368, DOS 27(6flK> 36/SOQ 14,720 22,400 101,520
Midh Bond Water
Htespgy HN toiv' ^^ Kaste l^w Ifeste Itesiiifcing Effluent gNapploamtal Data
tear I^aa3 l£iad level
litera^Sec GMP Mg,?*L
.31 63.0 1000 pH 6,0-9.0
63,0 1000 1*1 6,0-9,0 F 30
P 40, N 40 See note beLcw
*31 252 4000 HO disetenp
PH 6-0-9, F 15
F 30
21-5 Not ftppli™ Not: finxUL- No diac*iarg& this is &n «*n*i^e»rator to
cabla cable ooeKsentrate feed st!i^wi
10 . 5 Ktafc flppli- ftat ftp^ili.^ Ho diadhaige
cabte cable CoBt, of mM on to
10,5 Hot flppli- sot ftppli* Sb dlseha»3» Ccst of ^KUng this aystaB
qable C^Jle to a rsarf pl^it (B)
JU t !*ofc ^jpll* He* j^pli* ND diSEJiarge CB)
1 All out tigaam an fcar'"^juat
                                                                                                                                        EW material $1.40 ier 1000
                                                                                                                                        SO.SA px 1000 gaUms tnslaii; tutal ownll cost
                                                                                                                                                                 31,90 per 1000 gallam

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PAIL.Se 1 f nr.Cont.ained: Process

This system is one that is to be added to an  existing  unit  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-constructed 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 $40,000
to $46,000.

Pondwater^Use^For^Suj.f uric_Rc|d_pj.lut ion-i:E JInternal _Method)

There are two types of costs listed here.  One is for  adding  to
an existing system and the other 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 to 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 equipment.

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.
                                   135

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                                  EFFUJEtfl QUALITY
SLBCPBfOCKf
Ammonia




Urea
Anmonium
Nitrate


Refer to Figure 1 *lnterest On
TREAnMUfl? ALTERNATIVES Par Reference Investment Mcney *Dspreciatir
$ $ $
B AnracniaA*»3ensate 25 217,920 16,335 21,790
Stripping
B Integrated Armenia/
Condensate Stripping 26 112,700 8,455 11,270
System 32 20,424 1,530 2,040
C Biological Treatnent
Nitrificaticn-^enitrificaticn 30 110,000 8,250 11,000
E AnnoniaA^ondensate Air
Stripping 27 96,600 7,245 9,660
B Hydrolysis Urea 28 231,000 17,325 23,100
C Urea Hydrolysis 29 153,180 11,490 16,650
B Nitrate Removal by Ion
Exchange 31 580,000 43,500 58,000
C Biological Treatment
Nitrttlcation-DMiitrification
E Anncnium Nitrate Effluent
Utilization 53 132 ,020 9 ,900 13,200
* All oast figures are for August 1971
•Operating & Maintenance
Costa (Excluding
$
8,720
4,510
817
24,400
1,260
9,240
6,130
183,200

5,280
*Energy and
Fewer Costs
$
196,815
120,500
5,600
12,300
5,250
149,220
54,650
132,000

29,200
*Total 	
Animal
Costs
$
243,660
144,735
10,000
55,950
23,415
198,910
88,920
418,000

57,585
Energy *M kwh/ Raw Waste
Year Load
Liters/Sec
12.3 17.6
7.5 17.6
.35 6.3
.77 27.4
.33 17.3
9.3 4.15
3.4 1.6
8.2 63.5

1.8 5.05
Raw Waste Resulting Effluent
Load Level
GPM Mj/L
280 25 NH3-N
280 25 NH3-N
100 >25 Oil
5 NH3-N
435 5 NO3-H
275 10 NH3-*I
50 NH3-N
66 100 ORG-N
26 30 NH3-K
60 OfiG-N
40 t«3-N
1010 40 NH3-N

80 —
Resulting Effluent
Level
lb/1000 ten
84 KH3-N
84 NH3-N
>30 Oil

33 H**
40 NH3-N
80 ORG-N
9.4 NH3-N
19 ORG-N
485 NH3-N
485 N03-N

-
Supplemental Data
(A)
(A)
(A)
'
(A)
(B)
(B)
(C)
See Anocnia Alternative C
Use effluent as nitric a*-*'*
ahoccber mekeif) (O
(A)  900 kkg/dcy (1000 ten/day) AmrOTia Plant
(B)  900 kkg/day (1000 ton/day) Urea  (Total ftscycle) Plant
(C)  900 kkq/day (1000 tnVaay) amcnium Nitrate Plant

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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.

Ammonia/Condensate Air Stripping

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 Urea Hydrolysis

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  st.art-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.

Proprietary Urea Hydrolysis

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  opera-ting surveilance could amount from $2,000 to
$9,000.


                                   138

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Biological Treatment {Njtrification-Denitrification)

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 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.

Oil/Grease Removal

The oil/grease removal systems  may be used as 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.

Ammonium Nitrate Effluent Utilization

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.


                                    139

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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.
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Non-Water Quality Aspects of Treatment and Control Technologies

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 subsurface 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.
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                           SECTION IX
          BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
                            AVAILABLE

                   GUIDELINES AND LIMITATIONS
INTRODUCTION

The effluent limitations which must Jbe achieved by July  1,  1977
are  based on the degree of effluent reduction attainable through
the  application  of  the  best  practicable  control  technology
currently  available.  For the 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/or 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 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,  or  by-products.   Cooling
tower water is not covered in these limitations but will  be  the
subject  of  a  later study by EPA.  All values of guidelines and
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limitations are expressed as consecutive 30 day averages in units
of kilograms of 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  of  two  times  the  30  day  averages  are
established.   Because  extensive long term data is not available
for each of the subcategories it is necessary  to  rely  on  data
from  other parts of the fertilizer industry as well as data from
other similar industrial categories.  Based on  this  information
and  using  good  engineering judgement on the reliability of the
treatment systems involved, a factor of two appears generous.

Based upon the information 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 SUBCATEGORY
                       GENERAL DESCRIPTION
Eleven  phosphate  fertilizer plants were surveyed and studied to
determine the levels  of  pollutants  being  discharged  and  the
effluent  treatment  methods  being  used for control.  Phosphate
fertilizer plants do not need to discharge  process  waste  water
(gypsum  pond  water) continuously.  The pond water is re-used in
the process and a discharge is needed only when there is rainfall
in excess of evaporation.  For this reason limitation  quantities
are  not  based  on  production  but on rainfall conditions.  The
effluent quality is based  on  the  characteristics  of  properly
treated water released from the gypsum pond.

Best Practicable control Technology Currently Available includes:

A.  Gypsum Pond ^Contaminated) Water Treatment

    Double lime treatment  of  gypsum  pond  water  has  been  in
    industrial  use  for  some  15  years.  First stage treatment
    takes the pH to 3.5 to 4.O.  second stage treatment takes the
    pH to  6.0  to  9.0.   This  reduces  the  phosphate  (as  P)
    concentration   to   10-40  mg/1  and  the  fluoride  (as  F)
    concentration to 15 or less mg/1.  Radium 226 is precipitated
    to a sufficiently low concentration by lime treatment to a pH
    of 8.0.  Pond design and operation to leave enough  freeboard
    to  contain  a  10 year storm is required as best practicable
    control  technology.   Operation  to  maintain  the  required
    freeboard can include proper treatment and release of water.

B.  Sulfuric Acid Plan-L 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  reuse.   A  more  detailed  discussion  of   this
    technology is included in Section VII.

Effluent Limitations Guidelines

The  following  limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged  after
application  of the best practicable control technology currently
available by a point source.

    1.   Subject to the provisions of paragraphs (2), (3) and (4)
         there shall be  no  discharge  of  process  waste  water
         pollutants into navigable waters.

    2.   A process waste water  impoundment  which  is  designed,
         constructed   and   operated   so   as  to  contain  the
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         precipitation from the 10 year, 24 hour  rainfall  event
         as established by the National Climatic Center, National
         Oceanic  and  Atmospheric Administration for the area in
         which such impoundment is  located  may  discharge  that
         volume of process waste water which is equivalent to the
         volume  of  precipitation that falls within the impound^
         ment in excess of that attributable to the 10  year,  24
         hour rainfall event, when such event occurs.

    3.   During any calendar month there may be discharged from a
         process waste  water  impoundment  either  a  volume  of
         process  waste water equal to the difference between the
         precipitation for  that  month  that  falls  within  the
         impoundment  and  the evaporation for that month, or, if
         greater, a volume of process waste water  equal  to  the
         difference between the mean precipitation for that month
         that   falls   within   the  impoundment  and  the  mean
         evaporation  for  that  month  as  established  by   the
         National   Climatic   Center,   National   Oceanic   and
         Atmospheric Administration for the area  in  which  such
         impoundment is located (or as otherwise determined if no
         monthly  data  have  been  established  by  the National
         Climatic Center).

    4.   Any process waste water discharged pursuant to paragraph
         3  of  this  section  shall  comply  with  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)    70                35
fluoride as  (F)     30                15
total suspended
  nonfilterable
  solids           50                25
The pH of the water discharged shall be within
the range of 8.0 to 9.5 at all times.

Rationale for Best Practicable control Technology
Currently Available

The  criteria  used for selection of the treatment technology was
information  obtained  at  exemplary  plants  through   sampling;
inspection   and   review  of  plant  operations;  collection  of
validated historical effluent data; and direct  discussions  with
responsible  plant  operational personnel for positive definition
of  treatment  methods  and  analytical  procedures.   Additional
information   was  gathered  from  technical  literature,  direct
contacts with  experts  and  consultants,  and  discussions  with
/endors  of  treatment equipment and services.  Consideration was
also given to application of industry transfer  technologies  for
specific contaminant treatment.
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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, 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.always results from excessive rainfall.

Another  factor  is  the   treatment   limitations.    Particular
reference  is to the residual P 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 10-60 mg/1.  Additional  neutralization  (third  stage)   to
raise  the  treated  water  pH  to  9-11  will  effect  a P level
reduction to the 2-25 mg/1 range.

A limitation for ammonia (as N)  was established in  the  proposed
guidelines  but  was dropped from the requirement.  This was done
because control required a process  change  and  because  ammonia
levels  in  existng  gypsum  ponds are very high.  Lime treatment
does not reduce the ammonia content of the effluent.  The control
technology for control of ammonia is the ammonium phosphate self-
contained process.  During normal operation this process does not
release ammonia to the gypsum pond water system.   The  source  of
ammonia  in  the  pond  water  is equipment wash out contaminated
water  sprays  from  other  process  units  and  other  non-point
sources.    One  plant  that  uses  the  self-contained  ammonium
phosphate technology has an N concentration in the range of 25-66
mg/1 in the gypsum pond water.  The higher  levels  to  600  mg/1
occur   when  there  is  no  pond  water  discharge.   Additional
collection and treatment of ammonia laden wastes can  be  carried
out if necessary to maintain low ammonia nitrogen concentration.

Double  lime  treatment  to  a  pH  of 8.0 ato 9.5 is required to
achieve Optimum removal of radium 226 to minimize its hazards.
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                  NITROGEN FERTILIZER INDUSTRY

                       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.  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 control Technology Currently Available Includes:

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.  Urea Hydrolysis

    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
    effluent  limitations  are  available  from several different
    sources.

C.  Containment  (Ammonium Nitrate)

    Leak control, spill control, containment and re-use of  waste
    material  and  good housekeeping is the technology to be used
    to meet effluent limitations for ammonium nitrate.
D.  Containment /Nitric Reid)

    Nitric  Acid  is  produced  with  no  process   waste   water
    discharge.   Leaks and spills are controllable and can be re-
    used in a nitrogen fertilizer complex.  Cooling water will be
    the subject of a later EPA study.

2.  Oil Separation

    Design technology  for  API  oil  separators  has  been  used
    effectively  for years and can now be applied to the nitrogen
    fertilizer industry.  Segregation of oil  laden  streams  and
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    separation  of  oil  from  these  streams  will  be needed to
    achieve a satisfactory effluent.

Proposed Effluent Limitations Guidelines

The following guidelines are the effluent waste water limitations
for  the  ammonia,  ammonium  nitrate,  nitric  acid,  and   urea
sufccategories.


Parameter           Units                  Subcategory

                                Ammonia      U£ea.    Ammonium Nitrate

NH3-N          kg/kkg of product   0.063   0.0375        0.0375
  ~~           (lb/1000 Ib)                  0.05*         0.1*
Organic N      kg/kkg of product    -      0.175
              (lb/1000 Ib)                  0.5*
NO3^N          kg/kkg of product    -       -            0.05
              (lb/1000 Ib)                                0.11*

*Effluent limitations for plants that prill their product.

The  above  limitations  apply  to  the  maximum average of daily
values for any period of 30 consecutive days.  For ammonia (as N)
and nitrate (as N) the maximum for any one day is  twice  the  30
day maximum average.  For organic nitrogen (as N)  the maximum for
any one day is 2.5 times 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 the limitation
for the nitric acid subcategory.

Rationale 6 Assumptions for Selection of Technology

The guidelines used for 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 of the fifteen plants 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 use in
the fertilizer industry.

The 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
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.
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Ammonia  steam  stripping  is one treatment method which is being
used by the fertilizer  industry  successfully  at  a  number  of
locations.   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 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  v?hich  is  acceptable  for the 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  ammonium nitrate limitations are based on the average of the
best three plants studied that do not  use  ion  exchange.    They
achieve this level of performance by leak control, spill control,
good  housekeeping  and  containment and reuse of waste material.
Ion exchange for treatment of ammonium nitrate  wastes  is  being
developed   but   has  been  judged  to  be  very  expensive  and
incompletely  developed  for  use  as  best  practicable  control
technology currently available.

Limitation  for oil and grease was considered for the ammonia and
urea subcategories where compresssors  are  used.   However,  the
reproducibility  of  the  oil  and grease test is poor at the low
concentrations  that  occur  when  properly  controlled  in  this
industry.   For  this  reason,  no  limitation is established but
control based on appearance of the  effluent  and  water  quality
will require segregation and separation for oil removal.
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                            SECTION X

             BEST AVAILABLE TECHNOLOGY ECONOMICALLY
                           ACHIEVABLE

                          INTRODUCTION

The  effluent  limitations which must be achieved by July lr 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
of  control  technology  that  has  been  achieved  or  has  been
demonstrated  to  be  capable  of  being designed for plant scale
operation  up  to  and  including  no  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  fron
         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, or by-products.

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 SyBCATEGQRY

Best available technology economically achievable includes:

Wet Process Phosphoric Acid - Pond Water
Dilution of Sulfuric 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.

Proposed Best Available 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 only
recently 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 on  one
of  the  treatment  methods to justify its incorporation into the
design of two other 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  now 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 P2IO.5 values  in  the  gypsum  pond  water.   It  is  also
possible  through better reclamation procedures of uncontaminated
steam 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.  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 Best Available Technology Economically Achievable

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                  Subcategory

                                Ammonia      Urea    Ammonium_Nitrate

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

* Effluent limitations for 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 subcategory.

Rationale and Assumptions for Selection of Technology

Because  there will be changes before 1983, the economic analysis
of any treatment system will change.  Therefore, the selection of
1983 technology is based more on the  availability  of  processes
than  on  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 RECOMMENDATIONS

                          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 of best practicable
control technology currently available a  determination  of  what
higher  levels of pollution control are available through the use
of improved production  processes  and/or  treatment  techniques.
Thus,  in  addition  to considering the best in-plant and end-of-
process control technology, new source performance standards  are
to  be based upon an analysis of how the level of effluent may be
reduced by changing the production process  itself.   Alternative
processes,  operating . methods  or  other  alternatives are to be
considered.  However, the end result of the  analysis  identifies
effluent   standards   which  would  reflect  levels  of  control
achievable through the use of improved production  processes  (as
well as control technology), rather than prescribing a particular
type  of process or technology which must be employed.  A further
determination which was to be made  for  new  source  performance
standards  is  whether  a  standard  permitting  no  discharge of
pollutants is practicable.

The following factors were  to  be  considered  with  respect  to
production  processes which were analyzed in assessing new source
performance standards:

    a.   The type of process employed and process changes;

    b.   Operating methods;

    c.   Batch as opposed to continuous operations;

    d.   Use of  alternative  raw  materials  and  mixes  of  raw
    materials;

    e.   Use  of  dry  rather  than  wet   processes   (including
    substitution of recoverable solvents for water); and

    f.   Recovery of pollutants as by-products.

PROCESS WATER GUIDELINES

Phosphate Subcateqory

It is  recommended  that  new  source  performance  standards  be
identical   to   the  1983  limitations  for  all  new  phosphate
fertilizer plant sources.
                                   155

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Nitrogen^Fertilizer Industry

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 Technology (Process Improvements}

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.

B.  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 velocity 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 3%  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

The following guidelines are recommended for new source  effluent
waste  water  standards  from  the  ammonia,  urea,  nitric acid,
ammonium nitrate and subcategories:
                                   156

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Parameter           Units                  SubcatecrorY

                                Ammonia      Urea    Ammonium Nitrate

NH3-N            kg/kkg of product 0.055     0.0325      0.025
                (lb/1000 Ib)                  0.0325*     0.05*
Organic-N        kg/kkg of product -         0.12
                (lb/1000 Ib)                  0.35*
NO3--N            kg/kkg of product -          -          0.0125
                (lb/1COO Ib)                              0.025*

* Effluent limitations for 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 6 Assumptions in the Development 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 leaks.  Since much of the
1983  technology  is  not  commercially  available,   the   above
limitations   represent   engineeringing   judgment  as  to  what
                                   157

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improvements can be implemented beyond best  practicable  control
technology currently available.

Pretreatment Requirements 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 owned treatment works  is
recommended for the phosphate and nitric acid subcategories.  For
the  remaining  subcategories 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.
                                    158

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                           SECTION XII

                        ACKNOWLEDGEMENTS

    The Environmental Protection Agency would like to  thank  Mr.
Robert  Heinz,  Mr.  Edgar  Bailey  and  Mr.  Donald Ross of Davy
Powergas, Inc. for their aid in preparation of this report.

    The project officer would like to thank his associates in the
Effluent Guidelines Division, particularly  Messrs  Allen  Cywin,
Ernst P. Hall, Walter J. Hunt and Michael W. Kosakowski for their
valuable suggestions and assistance.


    Special  appreication  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.  Appreication is also given  to  Ms.  Kit
Krickenberger who coordinated the secretarial staff assignments.

    Thanks  are  also  given to the members of the members of the
    EPA working group/steering committee  for  their  advice  and
    assistance.  They are:


Mr. Walter J. Hunt, Effluent Guidelines Division, Chairman
Mr. Elwood E. Martin, Effluent Guidelines Division, EPA.
Mr. Harry Trask, Office of Solid Waste Management Program, EPA.
Mr. John Savage, Office of Planning and Evaluation.
Mr. Srini Vasan, Region V,
Dr. Edmond Lomasney, Region VI,
Mr. Paul DesRosiers, Office of Research and Monitoring,
Dr. Murray Strier, Office of Permit Programs,
Mr. Ray McDevitt, Office of General Counsel,
Mr. Richard C. Insinga, Office of Planning and Evaluation.
Dr.  Robert  R.  Swank,  Jr., Office of Research and Development,
    NERC - Corvallis, Athens, Georgia.
Mr. Michael w. Kosakowski, Effluent Guidelines Division,


    Acknowledgement and appreciation is extended to the following
companies, institutions,  associations,  laboratories,  agencies,
and  persons  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, Brewster, Florida
U.  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
                                   159

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10.  Cominco-American, Hoag, 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, Donaldsonville, 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, Armonk, New York
31.  Mr. A. L. West, Lakeland, Florida
32.  Dr. James A. Taylor, Lakeland, Florida
33.  Mr. W. A. Lutz, Weston, 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 Madison Avenue, New York, New York
41.  Battelle Northwest, Richland, Washington
42.  United  States  Steel  Agricultural  Chemicals   Corporation,
    Bartow, Florida.
                                   160

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                          SECTION XIII
                           REFERENCES
A.  Inorganic Fertilizer and Phosphate Mining Industries -  Water
    Pollution 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 Wastewater 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 Rempyal in a 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.  Ammonia and Synthesis Gas

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

E.  Industrial Pollution Control Handbook

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

F.  Gauging and sampling 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
    Studies Program

    Group  6  Fertilizers  prepared  by  Wellman-Powergas,  Inc.;
    Lakeland,   Florida,   33803,  for  Environmental  Protection
    Agency, July, 1971, Contract No. 68-01-0029.

H.  The Phosphate Industry in the United States

    by  E.G.  Houston  Tennessee  Valley  Authority,  Office   of
    Agricultural  and  Chemical Development, Division of Chemical
    Development, Muscle Shoals, Alabama, July, 1966.
                                  161

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I.  commercial Fertilizer Yearbook ~ 1970

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

J.  Characteristics of the World Fertilizer Industry - Phosphatic
    Fertilizers                                   ~

    by  Travis  Hignett,  Director   of   Chemical   Development,
    Tennessee  Valley Authority, Muscle Shoals, Alabama, December
    1967,  TVA Report 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  Requirements  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.

M.  World Nitrogen Plants  1968-1973

    Chemical Products Series Report-May 1969,  Stanford  Research
    Institute; Menlo Park, California, 9U025.

N.  Phosphatic Fertilizers - Properties and Processes

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

O.  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 Indus-try Facts  Book  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 Criteria

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

R«  Handbook of Dangerous Materials

    N.I Sax, Reinhold Publishing Corp.  New York, New York, 1951.
                                   • 162

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S.  Nitrates in Human Health

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

T.  Industrial Water Pollution control

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

U.  Phosphorus and ;Ets Compounds

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

V.  Cadmium in Rock Phosphate Ores

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

W.  Standard Methods for  the  Examination  of_  Water  and  Waste
    HaterT  13th  edition,  American  Public  Health  Association
    (1971).

X.  Methods for Chemical  Analysis  of  Water  and  Wastes,  EPA,
    National  Environmental  Research  Center, Analytical Quality
    Control Laboratory, Cincinnati, Ohio (1971) .
                                   163

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Page Intentionally Blank

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                           SECTION XIV                         '

                            GLOSSARY


All  underlined  numbers  within  a  chemical  formula  represent
normally subscripted numbers.  For example, H^O 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 •  H2O.   Also  referred  to  as  allophanamide  and
cabamylurea.

Boiler Slowdown

A small amount of boiler feed water wasted to remove the build up
of contaminants from 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)
                                   165

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Cooling Water Blowdown

Small quarvti-ty 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

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 technology 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 under study.

GTSP

Granulated triple superphosphate.


Nitrification

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  acicular  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.
                                   166

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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 a 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

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

TSP

Triple superphosphate.
                                   167

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                                             METRIC UNITS
                                           CONVERSION TABLE
CTl
GO
MULTIPLY  (ENGLISH UNITS)

  ENGLISH UNIT       ABBREVIATION

acre                   ac
acre - feet            ac ft
British Thermal        BTU
  Unit
British Thermal        BTU/lb
  Unit/pound
cubic feet/minute      cfm
cubic feet/second      cfs
cubic feet             cu ft
cubic feet             cu ft
cubic inches           cu in
degree Fahrenheit      °F
feet                   ft
gallon                 gal
gallon/minute          gpm
horsepower             hp
inches                 in
inches of mercury      in 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

    CONVERSION

      0.405
   1233.5
      0.252

      0.555

      0.028
      1.7
      0.028
     28.32
     16.39
      0.555 (°F-32)*
      0.3048
      3.785
      0.0631
      0.7457
      2.54
      0.03342
      0.454
       3,785
      1.609
(0.06805 psig  +1)*

      0.0929
      6.452
      0.907

      0.9144
                                                                       TO OBTAIN (METRIC UNITS)

                                                                   ABBREVIATION      METRIC UNIT
ha
cu m
kg cal

kg calAg

cu m/min
cu m/min
cu m
1
cu on
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
km
atm

sq m
sq on
kkg

m
hectares
cubic meters
kilogram-calories

kilogram calories/
 kilogram
cubic meters/minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
kilowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres
  (absolute)
square meters
square centimeters
metric tons
  (1000 kilograms)
meters
         *Actual conversion,  not a multiplier

-------