&EPA
         United Slates
         Environmental Protection
         Agency
          Industrial Environmental Research
          Laboratory
          Research Triangle Park NC 2771 1
EPA-600 7-79-247
November 1 979
EPA Evaluation of Water
Plant Lime Sludge in an
Industrial Boiler FGD
System at Rickenbacker
AFB
         Interagency
         Energy/Environment
         R&D Program Report

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                  RESEARCH REPORTING SERIES


Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional  grouping was  consciously
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The nine series are:

    1.  Environmental Health Effects Research

    2.  Environmental Protection Technology

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    4.  Environmental Monitoring

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    8.  "Special" Reports

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This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
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health  and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
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effects; assessments  of, and development of, control technologies for  energy
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                       EPA REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                         EPA-600/7-79-247

                                             November 1979
EPA Evaluation of Water Plant Lime Sludge
     in an  Industrial  Boiler FGD  System
              at Rickenbacker AFB
                             by

                         Robert J. Ferb

                    Cottrell Environmental Sciences
                         P.O. Box 1500
                    Somerville, New Jersey 08876


                   Interagency Agreement No. 05-0718
                     Program Element No. EHE624
                   EPA Project Officer: John E. Williams

                Industrial Environmental Research Laboratory
              Office of Environmental Engineering and Technology
                    Research Triangle Park, NC 27711
                          Prepared for

                U.S. ENVIRONMENTAL PROTECTION AGENCY
                   Office of Research and Development
                       Washington, DC 20460

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                           ABSTRACT
A test program, which evaluated the use of lime sludge  (a waste
product  from  water treatment  plants)  as  a  reagent  for  SO2
removal  in  an  industrial  sized  flue  gas  desulfurization
system,  surveyed potential sources of lime  sludge supplies,
developed  a  lime  sludge  handling  system  and  determined  the
economics  of  lime  sludge utilization  was  completed.    The
program was started in  September  1978,  tests were conducted at
Rickenbacker  RAFB   in  Ohio  and  work  was completed  on  the
program in February 1979.

The results of the program demonstrate that lime sludge is an
ideal reagent for  flue gas desulfurization.   Sources  of lime
sludge  exist   in   areas  where  flue  gas   desulfurization  is
practiced and the  cost of  using  lime  sludge  is significantly
lower  than  that  for conventional  reagents such as lime  and
limestone.

Lime  sludge  reacts similarly  to lime as  FGD reagent  up to
stoichiometric ratio of 0.8.  At SO,  removal  efficiencies up
to 80% lime sludge utilization exceeded 95%.

Numerous  sources  of lime  sludge  are  located  in  midwestern
states where large deposits of high sulfur coal are found.  A
limited survey indicates that over 400,000 TPY of lime sludge
is  available.    Data  contained  in the  Lime  Chapter of  the
Bureau of Mines 1977 Mineral Year Book indicates that as much
as 4 - 5,000,000 TPY may be available.

Lime sludge handling facilities for a typical industrial sized
FGD system cost approximately $100,000 to  install and $55,000
per year  to operate.   The use of lime  sludge in  a  typical
industrial FGD system results in  annual savings of $63,000 and
$22,000 over lime and limestone respectively.  If lime sludge
disposal credits are included  an additional  annual saving of
$50,000 can be realized.

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                       ACKNOWLEDGEMENTS
         cooperation  of  the Base Civil  Engineering  Staff of
Rickenbacker AFB, is greatly appreciated.  Especially that of
James B.  Rasor, Associate  Base Civil Engineer,  and Herbert
Robinson, Scrubber Technician.

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                               CONTENTS
                                                      PAGE

    Abstract	     2
    Acknowledgement 	     3
    List of Figures	     5
    List of Tables	     6
    List of Abbreviations	     7
    1.   Introduction 	     8
    2.   Scrubber Tests	    10
              System Description	    10
              Test Program	    14
              Test Results	    17
    3.   Survey of Water Plants	    28
              Scope of Survey	    28
              Sources of Lime Sludge	    28
              Characterization of Lime Sludge ...    37
              Summary	    37
    4.   proposed Lime Sludge Handling System ...    39
              System Description	    39
              Capital Cost Data	    46
    5.   Economics of Lime Sludge Utilization ...    46
              Lime Sludge System Operating
              Costs and Cost Comparison
              Between Lime Sludge, Lime,
              and Limestone	    46
    6.   Conclusions	    50
    7.   Recommendations	    52
ppendices	    53
    A.    Conversion Factors British of SI Units.  .  .    54
    B.    Analytical and Test Methods	    56
    C.    Scrubber Test Data	    60
    D.    Water Plant Survey Data	    65

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                       LIST OF FIGURES

Number                                                 Page

  2-1     R-C/Bahco Scrubber System Flow
          Diagram	12

  2-2     R-C/Bahco Scrubber System Flow Diagram
          as Modified for the Program	13

  2-3     Dissolver Tank pH and SO2 Removal
          Efficiency During the Test Period	16

  2-4     SO2 Removal Efficiency as a Function
          of Lime and Lime Sludge Stoichiometry. ...  19

  2-5     SO2 Removal Efficiency as a Function
          of Limestone and Lime Sludge
          Stoichiometry	21

  2-6     The Effect of Lime, Limestone and Lime
          Sludge Stoichiometry on Dissolver pH  . . .  .  23

  2-7     Water Plant Sludge Size Distribution  ....  23

  2-8     Relative Reactivities of Limestone and
          Lime Sludge	25

  3-1     Weighed Average Hardness, by States
          and Puerto Rico of Water Delivered
          from 1,596 Public Supplier, 1962 ......  29

  3-2     Keystone's Map of the Coal Fields of  the
          United States	30

  4-1     Lime Sludge Handling System	41

  4-2     Lime Sludge Handling System Plan View. ...  42

  4-3     Lime Sludge Handling System	43

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                        LIST OP TABLES
Number                                                 Page
  2.1     Summary of SO2 Removal Test Data from
          RAFB Using Lime Sludge	   18
  2.2     Lime Sludge Slurry Analyses 	   26
  2.3     Lime and Limestone Slurry Analyses. ....   27
  2.4     Lime Sludge Specific Gravity and
          Solids Content	   27
  3.1     Water Plant Survey Data Summary 	   31
  3.2     Water Plants Using Lime Softening
          and Average Daily Water Rates 	   33
  3.3     Lime Sludge Totals by State	   36
  3.4     Lime Sludge Survey Sample Analyses	   38
  4.1     Lime Sludge Handling System
          Design Criteria 	   40
  4.2     Lime Sludge System Cost Summary	   46
  5.1     Reagent Requirements and Costs	   48
  5.2     Incremental Operating Cost for Lime
          Sludge Utilization System 	   48

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              LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS

BTU       British thermal unit
cm        centimeter
d         day
fps       feet per second
gal       gallon
gpm       gallon per minute
j         joule
ft        feed
hr        hour
in        inch
k         kilo
1         liter
Ib        pound
mi        miles
m         meter
rag        milligrams
mm        million
ppm       parts per million

wt        weight

sec       second

I.D.      inside diameter
T         ton
TPY       ton per year
Mg        megagram

y         year

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                            SECTION 1

                         INTRODUCTION
      This  program has  demonstrated that it is technically and
 economically  feasible  to use lime  sludge as a reagent in Flue
 Gas  Desulfurization  (FGD)  Systems.   This result offers oppor-
 tunities to alleviate  two significant environmental problems,
 one  in  solid  waste disposal  and  one in air pollution control.

      Among the  major   problems  facing  operators  of  public
 drinking  water  supply facilities  is the  disposal of  solid
 wastes  from water treatment plants.  Among the wastes produced
 is lime sludge which is formed when lime is used for softening
 water supplies prior to distribution.   If  wide scale utiliza-
 tion of lime  sludge  in FGD  systems were undertaken,  it would
 virtually  eliminate  the need for lime sludge disposal.

      A  further  problem of FGD systems  themselves  is the cost
 of suitable SO, scrubbing reagents.  The use of lime sludge in
 an FGD  system is  significantly less expensive than the use of
 lime or even  limestone.

      In order to  understand  the  main  purposes of this program
 a brief description of  a typical  water softening process where
 lime sludge is produced is necessary.

      Lime  sludge  is  produced when lime  is  used  to  remove
 calcium and magnesium  hardness  from drinking  water  supplies.
 These cations which  are usually  present with  bicarbonate  and
 carbonate  anions  are  removed by the  addition of lime  in  the
 form of calcium  hydroxide.   The overall process,  as  il-
 lustrated  below for calcium  bicarbonate  and magnesium carbon-
 ate,

     Ca+++ 2HC03~" + Ca(OH)2  *  2CACO3  +  H20

     Mg"1"1"* C03—  + Ca(OH)2  +    Mg(OH)2 + CaC03

 results  in   the   precipitation  of  calcium  carbonate   and
magnesium  hydroxide  from  the water.    This precipitate,  the
 lime  sludge,  is  separated from  the  water  and accumulated  in
 lagoons or  ponds.  Typically the  lime sludge which is composed
 of 5  to 15 micron particles, contains 85 to 95% calcium car-
 bonate  and small amounts   of  magnesium  hydroxide.    These
 physical and  chemical   attributes  make lime  sludge an  ideal
 reagent for use in FGD  processes.

     There   is  one  further   factor  which  contributes sig-
nficantly  to the  potential usefulness of lime sludges.  This
 type of water  softening process  is  practiced at many locations

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in the midwest  where there are large  local  deposits of high
sulfur coal.    In  these  areas flue  gas  desulfurization  is
almost essential to permit expanded use of these fuels.

     The work described  in this report  is a continuation of an
earlier program  conducted at, Rickenbacker AFB  in  Ohio under
the sponsorship of the USEPA   .

     The primary objectives of this program are:

          o Determine the performance of an FGD system when
            using water plant lime sludge.

          o Determine the location of major sources of lime
            sludge

          o Determine the feasibility of handling lime sludge.

          o Determine the economics of using lime sludge as
            a reagent in FGD systems.

     Each of these  objectives are  dealt with  in  detail  in sub-
sequent sections of this  report.
    EPA Evaluation of Bahco Industrial Boiler Scrubber System at
Rickenbacker AFB, EPA-600/7-78-115 June  1978.

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                            SECTION 2

                        SCRUBBER TESTS
      The performance of an  FGD  system  is dependent upon many
 factors, reagent  performance  is one of the most  important.
 This portion of the program, the scrubber tests, demonstrated
 that lime  sludge  both  from materials  handling and  reagent
 reactivity  points of  view is  a  suitable  reagent  for  FGD
 systems.

      Since the tests were  conducted in  an FGD system designed
 to  handle  solid  reagents,  some   system  modifications  were
 necessary.   These modifications  are described first,  the test
 procedures are described next and finally the test results are
 presented.

 R-C/BAHCO SCRUBBING SYSTEM

      The FGD  system at Rickenbacker  Air  Force Base  (RAFB)
 which was  used  for  this test program is described in detail in
 the  previously  cited EPA  report1  '.    For  this program  the
 system  was  modified to  facilitate the  use of lime  sludge
 obtained from the City  of  Columbus  Morse Road water treatment
 plant.

      The test program consisted of  an  essentially  continuous
 run  designed to determine  SO,  removal at two levels  of  stoi-
 chiometry.                   •

 System  Description

      Hot flue gas  from each of  the Heat Plant  generators  at
  &FB is passed  into a common  flue which  contains a  bypass
  tack.   This  stack allows  makeup  air   to  be drawn  into  the
  ystem  at  low  load to maintain efficient  operation of  the
 ..echanical  collector  and scrubber.   Flue gas, with  or without
makeup air, is passed through a mechanical collector to remove
coarse particulate  matter  before entering the booster fan.

     This  fan forces flue gas  into  the first  stage of  the
scrubber where  it is vigorously mixed with scrubbing slurry in
an inverted venturi.  In this stage, flue gas is cooled to  its
adiabatic  saturation temperature and SO2 and particulate  are
scrubbed  from  the gas.  This partially  scrubbed gas  rises  to
the  second  stage  where  it  is contacted with  slurry  containing
fresh alkali  to  complete  the  required  SO~  and particulate
removal.   Gas  from  the second  stage enters a   cyclonic mist
eliminator  where  entrained slurry droplets are  separated from
the  gas  by  centrifugal   force   to produce an essentially
droplet-free effluent.

                               10

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     Pebble  lime  from  a  storage  silo  is slaked  and added
directly  to  the slurry  in the lime  dissolving  tank, ground
limestone can also be used.  The resulting fresh lime mixture
is pumped  to the  second  stage  (upper)  venturi  to  treat  the
flue gas stream.  The slurry flows by gravity from  the second
stage to the  first stage where  it contacts  hot flue  gas enter-
ing  the  scrubber.     This  countercurrent flow  arrangement
results in high SO- removal and efficient  reagent usage.

     Spent slurry flows by gravity  from  the first  stage of  the
scrubber  to  the dissolving tank.    Part of the  spent stream
leaving  this stage  is  diverted to  the thickener  where  the
slurry is concentrated to 35 to 40% solids.  Overflow  from  the
thickener returns to the dissolving tank and the underflow  is
pumped to a Hypalon-lined  sludge pond near the Heat Plant.

     The scrubbing system prior to  being modified  for  the test
program is illustrated  in  Figure 2-1.

     The  following  changes were made to  permit  testing with
lime sludge:

   o The slurry feed to the thickener was diverted directly to
     the sludge pond.  A spare sludge pump was used for pump-
     ing this material  to  the pond.

   o A portable gasoline  driven pump was used to unload lime
     sludge  from  tank  trucks  into   the thickener.     The
     thickener served as a feed tank.

   o A  recirculation  line  which  ran from the bottom of  the
     thickener to the lime dissolving tank was installed.   At
     the  dissolving  tank  a short  takeoff  line with  a manual
     control valve was  installed to  feed lime sludge  into  the
     dissolving tank.

These changes  were  accomplished by adding several  quick dis-
connects  into  existing  lines along with  some  new  lengths  of
hose.   Figure  2-2 illustrates  the  system  as modified  for  the
tests.

     The  use of quick  disconnects allowed the  system to  be
returned to normal operation after  the test work was completed
with a minimum of downtime.

System Operation

     With the above modifications, the  system was operated in
the following manner.
                                11

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                                             STACK
                 REAGENT SYSTEM
                        MODULE
LIME or
LIMESTONE
TRUCK
                 n
                                     MAKEUP
                                     WATER
                     LIME
                     STORAGE
                                           OVERFLOW
                                              TO
                                           ,  LIME
                                           DISSOLVING
                                             TANK
                                                                                 THICKENER
                                                                                        SLUDGE
                                                                                       TO POND
                                                                    R-C/BAHCO
                                                                    SCRUBBER
                                                                      BOOSTER
                                                                       FAN
                       THICKENER
                       OVERFLOW

                     LIME
                     FEEDER
                     & SLAKER
in-


Y
                                                             FLUE GAS
                                                             FROM HEAT
                                                             ^—PLANT

                                                         MECHANICAL
                                                         COLLECTOR
                                                     TO
                                                   FLY ASH
                                                   DISPOSAL
         UNLOADING'
         STATION
. L|ME      2nd STAGE PUMP
 DISSOLVING TANK
                                                                   MILL PUMP
                          Figure 2-1: R-C/Bahco Scrubber System Flow Diagram
               NC. 32.376.
                       LOGARITHMIC NORMAL.
                                                 GRAPH PAPCR
                                                        IN STOCK DIRECT FROM CODEX BOOK co.

                                                       (g|            PltMTCO IM U.S.A.
                                                                           . NORWOOD. MAES, O2OG2

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         REAGENT SYSTEM
                MODULE
        n
FROM THICKENER
UNDERFLOW
RECIRCULATION .
LIME or _
"X
LIMESTONE-*
TRUCK ^

J~-
V
N
\V

LIME
STORAGE
LIME
FEEDER
& SLAKER
^^
                                                         PORTABLE
                                                           PUMP
                                                                            TANK TRUCK
                                    STACK
                             MAKEUP
                             WATER
                                                           R-C / BANCO
                                                           SCRUBBER
                                                    1st STAGE  fi(p°gTER
                                                                          FLUE GAS
                                                                         FROM HEAT
                                                                          4—PLANT

                                                                      MECHANICAL
                                                                      COLLECTOR
                                                                FLY ASH
                                                               DISPOSAL
UNLOADING
STATION
-LIME      2nd STAGE PUMP
 DISSOLVING TANK
                                                          MILL PUMP
                                                                                        TO DISSOLVING
                                                                                        TANK
     Figure 2-2:  R-C / Bahco Scrubber System Flow Diagram as Modified for the Test Program

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      Lime  sludge was loaded into a compartmented tank truck at
 the Morse  Road  water treatment  plant  and  hauled  approximately
 32 km (20 mi.) to RAFB.  At the  scrubber site a gasoline driven
 self  priming  mud pump  was hooked  up to the tank  trunk  and the
 lime  sludge was pumped  via  a  7.6  cm  (3  in.)  hose into  the
 thickener.  The thickener was filled  during  the   day   with
 sufficient  material  to allow  operation through the night.   A
 sludge pump which  draws from the bottom of  the  thickener  was
 used  to circulate  lime sludge through the modified  flow  loop
 described  above.   At  the dissolving  tank, a side stream  was
 bled  off the circulating loop via a manual valve to maintain a
 predetermined pH in  the  R-C/Bahco scrubbing system.

      Spent  slurry  from the  scrubber  that was normally  fed to
 the thickener  prior  to pumping  to the sludge pond was  pumped
 directly to the pond via a spare  sludge pump.

 TEST  PROGRAM

      The test program  was designed to measure SO-  removal  ef-
 ficiency  over  a  range  of  lime  sludge-SO, stolchiometries.
 This  was accomplished during a continuous run of  approximately
 five  days.  All significant system variables other than stoi-
 chiometries were maintained  at  preferred  levels for the  test
 run.   These included:

      Total  gas  volume         59,000  to 76,000 Nm  /hr
                              (35,000  to  45,000  SCFM)

      Slurry Circulation       8,300 to 9,100 1/min
      Rate                     (2,200  to 2,400 gpm)

      First  and Second
      Stage  Pressure Drops     1.74 to 2.49 KPa  (7-10 in W.C.)

      Data  and  samples  were taken at  approximately four  hour
 intervals during testing.  A typical  data  sheet  and  a  summary
of  scrubber  test  data  are  located  in Appendix  C of  this
report.

      In addition to S02 removal  data,  handling characteristics
of  lime sludge  and scrubber  operation  were  observed both
during routine operation and during upset  conditions.

      The test  run  was  begun  on  October   27, 1978  with lime
sludge  from the Morse Road  water  plant.    Lime sludge feed
system piping changes  were made on October 27  and 28,   actual
testing was started on October 28.

     Dissolver  tank pH was selected  as the main variable  for
control of  the  lime sludge feed;  this choice was contrary  to
the initial selection of  direct  lime sludge feed  rate control.
                             14

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This change was made  on  the basis of the very rapid response
of scrubber system pH  to  changes  in lime sludge feed rate as
observed on October 27th.

     Two levels of pH were selected for  testing,  the  first was
a pH of 4.5  which  corresponded   to a   lime sludge-S02 stoi-
chiometry of about 0.6 and  the  second  a pH of 6.0 which cor-
responded  to  a stoichiometry  of  approximately 0.8.   These
levels of  pH  were selected  on  the basis  of  experience with
lime gained during  the prior test  work.   Normal system load
variations, as previously experienced,  produced further lime
sludge-SO2 stoichiometry variations above and  below the  levels
selected.

     A  histogram,  of  S02  removal  efficiency and  pH  versus
time, Figure  2-3,  illustrates system SO-  removal efficiency
and pH during the  test program.   The low pH portion of  the run
produced moderate  S02 removal efficiency i.e.  50% to  70% while
the  higher  pH produced  S02 removals of 75%  to 85%.   These
results  were  similar to  those  observed during  earlier tests
with lime  whe/x .operating at S02  concentration  in the  300  to
500 ppm  range1  .

     During the pretest  period on  October 27 an interesting
phenomenon occurred  in the  dissolving  tank.   The lime  sludge
feed to  the dissolving tank was interrupted and a sharp drop
in pH occurred.  The feed was resumed at a high  rate to bring
the pH up quickly.  When  this was done there was a rapid evolu-
tion of CO2 gas from the  reaction  of calcium  carbonate  in  the
lime  sludge  with  the  acidic slurry  in the  scrubber.   This
produced  a voluminous and  persistent  foam  which had  to  be
disperesed with a hose.

     This  foaming  occurred  again during an upset in the  test
program on the morning of October 30th.   At this time the  lime
sludge supply had been totally depleted after an overnight  run
and  the  feed  was  resumed at a high rate after  the first  tank
truck was  unloaded  in the morning.  This  penomenon  in  and  of
itself  does  not   interfere with   operation  of  the  system,
however,  otherwise  unnecessary operator time is required  to
disperse the  foam.

     With  a  permanent  lime-sludge  feed   system,   including
automated  pH  control,  this type  of pH  excursion followed  by
excessive  lime sludge  feed  would  not be likely to occur.
 / 2)
 v  'These results  are  reported  in  the  reference cited in foot-
 note  (1).
                               15

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  6.5

  6.0
  5.5
u
  5.0
5 4.5
                                          DISSOLVER TANK pH

                                          SO, REMOVAL EFFICIENCY %
  4.0
  3.0
                                                                          100
                                                                          90
                                                                          80
                                                                          70
                                                                            Ui
                                                                            O
                                                                            li.
                                                                            I
                                                                          An
                                                                          60
                                                                          50
                                                                          40
        10-29
                          10-30
10-31
11-1
                                  TEST PERIOD
          Figure 2-3  DISSOLVER TANK pH AND SO, REMOVAL EFFICIENCY
                     DURING THE TEST PERIOD

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TEST RESULTS

     The  results  of  the  scrubbing tests  indicate  that lime
sludges are  ideal  reagents  for use in FGD  systems.   This is
true both with  regard to  their reactivity and with regard to
their handling.  Conventional  equipment is capable of handling
lime sludge.

     During the testing 22 complete data  sets and samples were
taken more or less  at four hour intervals.   In accordance with
the scope of work,  nine data sets  were selected  at random from
these for complete  evaluation.   The results from  these nine
tests are summarized  in Table 2.1.

     The  same  approach that  was  used  in  earlier  work, non-
steady state testing, was employed during this  program.  This
approach is necessitated by the inherent  variability  in  boiler
load at RAFB.   Load  variations cycled  in a  time span similar
to the scrubbing system's 12  to 24 hour  residence time.  This
fact rendered steady  state-testing impossible.

     The   effect   of   this  situtation  was   minimized  by
taking data and samples  and  subsequently  analyzing  them to
determine  the  actual  levels of  lime  sludge  stoichiometry
during the  test period.   As indicated, this  approach does  not
permit precise  regulation of  variables;  however, a full range
of lime sludge  SO- stoichiometry was investigated and the  SO2
removal  efficiencies observed covered  the  range of interest
for most  industrial  FGD systems.

SOp Absorption

     SOj  removal  efficiency  ranged from about  52% to  nearly
85% during  the  test  program.

     During  the early part  of the  run, when  the system  pH  was
kept  in  the 4  to  5  range,  SO-  removal efficiency averaged
58.48%, lime sludge-S02 stoichiometry averaged 0.59  and  alkali
utilization was nearly  complete at 98.58%.

     During  the latter part of the test run when the  system pH
was maintained in the 6.0  to 6.5  range, SO-  removal efficiency
averaged  79.34%,  lime sludge-SO- stoichiometry averaged  0.84
and  alkali  utilization was 94.3t5%.   The high  levels   of  SO-
removal and alkali utilization observed during these tests are
very  similar  to those observed  for  lime during earlier  test
work cited  above.

     The  lime  sludge  data  is compared  to  earlier lime  test
data in Figure 2-4.  As illustrated by  the figure,  the  results
obtained  from lime sludge are indistinguishable from those for
lime up  to  a stoichiometry  of about 0.8.


                               17

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                                              TABLE 2.1
                                   SUMMARY OF SO. REMOVAL TEST AT
                                       RAFB USING LIME SLUDGE
Date/Time
Test
10/28/78
10/29/78
10/29/78
10/20/78
10/30/78
10/31/78
10/31/78
10/31/78
11/1/78
19:10(A)
3:10(B)
14:10(C)
2:10(D)
20:00(E)
4:10(F)
12:00(G)
20:OC(H)
4:00(1)
                               S0_%
        ""eats A thru D
        Tests E trhu I
Removal
Efficiency
66.5
60.3
51.8
55.3
82.2
78.6
76.5
84.4
75.0
Alkali/SO,
Stoichiometry
0.686
0.617
0.518
0.553
0.822
0.848
0.795
0.943
0.788
Average SO«
Removal Efficiency %


58.48
79.34
                                                            4.2
                                                            4.4
                                                            4.35
                                                            5.3
                                                            6.2
                                                            6.40
                                                            6.25
                                                            6.45
                                                            6.2
    Average
Stoichiometry

     0.59
     0.84
Reagent %
Utilization %
96.5
97.8
100.0
100.0
100.0
91.8
96.2
88.6
95.2
Average
Alkali
Utilization
98.58
94.36
of Total
CaCO,
93.7
89.7
100.
89.8
89.8
92.6
92.5
100.
92.6




Alkali
Ca(OH)2
6.3
10.3
-
10.2
10.2
7.4
7.5
-
7.4




These values are expressed in mole percent and alkali listed under Ca(OH)2 is a combination of Mg(OH>2 and Ca(OH>2
Ca(OH). reported as Ca(OH)2

-------
LJLJ
CC
CM
O
CO
   100
    80
    60
    40
    20
     0
          RAFB CODE REQUIREMENT
            LIME        '/
         UTILIZATION//*-
100%/
                 /

               ^90%
                              O SCREENING TESTS
                                              VERIFICATION TESTS
                              • LIME SLUDGE TESTS
                       i
                                   _L
             0.2       0.4       0.6      0.8       1.0

                  LIMESTOICHIOMETRY, MOLES, LIME/SO2
                                           1.2
     Figure 2-4: S02 REMOVAL EFFICIENCY AS A FUNCTION OF LIME
               AND LIME SLUDGE STOICHIOMETRY.

-------
      When  the lime  sludge  data is compared  to  earlier lime-
 stone S02  removal  data as  in Figure  2-5,  the  tendency  for
 decreasing  lime-sludge  utiliztion  at higher levels  of stoi-
 chiometry  is more pronounced.   It  is important  to  note  how-
 ever,  that even  at  these higher levels of stoichiometry,  lime
 sludge exhibits  substantially  higher levels of alkali utiliza-
 tion  than limestone.

      During   the  testing,   the  scrubbing  system  exhibited
 another distinctive characteristic,  i.e., scrubber  slurry pH
 sensitivity   to   stoichiometry.    This   characteristic   was
 observed in  earlier lime tests  but was not typical  of lime-
 stone.   This  behavior  is thought  to  be  related  to  both  the
 reactivity of  the reagent and  to the  actual  reagent inventory
 in  the scrubbing system.  High pH sensitivity to stoichiometry
 is  associated  with  highly reactive  reagents  which do not  tend
 to  accumulate  in the system.   Thus,  with lime  there  is  very
 little  in  process  inventory  and  nominal  buffering  in  the
 system.    Limestone on the  other hand,  tends  to  be  less
 reactive and substantial in process  inventories are normally
 present.   This  limestone  reagent  inventory  tends  to  dampen
 changes in  the  system  making  the pH  somewhat  insensitive to
 changes in stoichiometry.  The pH and stoichiometry data  from
 the lime sludge  tests  as well as earlier lime  and  limestone
 data  are plotted in Figure  2-6  to  illustrate their  relative
 characteristics.

      This lime-like behavior of lime  sludge, in spite  of  its
 approximately  90% calcium carbonate content,  probably results
 from  both  it's  calcium  and  magnesium hydroxide  content,  and
 more  importantly, from  its particle size.

      The lime  sludge tested  at RAFB had the  size distribution
 illustrated  in Figure 2-7 with  a mass median particle size of
 approximately  6-7 microns.   This size  distribution,  which  was
 found  to be  typical  for  lime sludges*  ,  results  in  ap-
 proximately  ten  times as much surface  area for reaction as  the
 same   weight   of  a  typical   74  micron   (200   mesh)   ground
 limestone.

     This  combination   of  fine  particle   size  and  hydroxide
 content  produces  a  reagent which behaves  very much  like lime
 with  regard  to S02  removal  capabilities,  reagent utilization
 and system pH  sensitivity to stoichiometry.

     Research-Cottrell  has performed  in house studies  of  the
 reactivity of  various  high  calcium content  ground  limestone
 with dilute  sulfurous acid solutions.   When  the  reactivity of
 the  lime sludge used  in the  scrubbing  tests  at  RAFB   is


 ^   See Section  3.0 of this  report  Characteristics of Lime
Sludge

                             20

-------
    100
    90
O
z
UJ
o
LL
U.
UJ
UJ
lT
 M
O
CO
/
                75% REAGENT UTILIZATION
     50
     40
  /
 /
                           o LIMESTONE TEST DATA
                           • LIME SLUDGE TEST DATA
                   I
                   t
                                i
l
      0.6    0.8     1.0     1.2    1.4     1.6     1.8

           REAGENT • SO, STOICHIOMETRIC RATIO


   Figure 2-5:  SO2 REMOVAL EFFICIENCY AS A FUNCTION OF
             LIMESTONE and LIME SLUDGE STOICHIOMETRY
                            21

-------
       9.0
   I
   a
   cc
   ui
M
10
       8.0
        7.0
        6.0
        5.0
        4.0
          0
                 o LIME TESTS
                 O LIMESTONE TESTS
                 • LIME SLUDGE TESTS
                                    l   •    I
                                                                      O

                                                                      O
                                                          O
                                                          o
                                                            o   o
0.2
0.4
0.6      0.8
   STOICHIOMETRY
1.0
1.4
1.6
                Figure 2-6:  THE EFFECT OF LIME, LIMESTONE AND LIME SLUDGE
                           STOICHIOMETRY ON DISSOLVER pH.

-------
  a:
  111
(OUJ
OC Ul
— UJ
  Ul
    99
    95
    90
    80
^5 70
    60
"•2 50
U.I- OU


H< 40


    30
    20
 ± 10



IT  5
                                                MEDIAN PARTICLE

                                                SIZE 6.5 microns
                I
                          I	I
      1         2     3  4  5  6  78910       20    30  40 50  70


                          PARTICLE DIAMETER, microns


       Figure 2-7  WATER PLANT SLUDGE  SIZE DISTRIBUTION
                                                               100
                                   22

-------
compared to this data (see Figure 2-8) it is apparent that the
initial rate of  reaction  is  substantilly faster  than that for
ground  limestone  and  the final  degree  of  reaction is  also
greater.    This comparison  further  confirms  the  lime-like
characteristics  of  lime  sludges  when  compared  to  ground
limestone.

     The scrubber  slurry analyses data summarized in Table 2.2
illustrates another  interesting result  of these  tests regard-
ing  the chemical composition of the  scrubber  slurry samples.
These  samples  contained   substantial quantities  of calcium
sulfate  as  gypsum  (approximately  88%)  with  little  or  no
calcium sulfite (less  than  1%).    This  indicates   that  sub-
stantial oxidation of the absorbed SO^ occurred.   Earlier test
work  with  limestone  at the same  30o  to 500 ppm   SO,   level
produced a similar high gypsum content slurry.  An analysis of
a  typical  limestone  slurry as  well  as one when lime was  used
is  illustrated  in Table   2.3,  in  which  the calcium sulfite
content was 54.5%  and the  gypsum content was only 33.4%.   The
slurries produced  during these tests are very similar to lime-
stone slurries,  i.e., predominantly calcium  sulfate, in spite
of the lime-like characteristics of the  lime sludge.

Lime Sludge Handling

     The  handling  of  lime  sludge  is a  critical element  in
evaluating  its suitability  as  an  FGD  reagent.   During  this
test  program  lime  sludges were successfully loaded,  trans-
ported and unloaded using  a tank truck and conventional  slurry
pumps.

     The tank  trucks were loaded with lime sludge at the Morse
Road  water plant  via  their  lime  sludge pumps.    After  the
twenty  mile  trip  to RAFB  the  trucks  were  unloaded without
agitation via  a gasoline engine driven  self  priming  mud pump.

     After  transport and  unloading   into  the thickener  some
settling occurred.   During  testing  periodic measurements  of
the  thickener  under flow  specific  gravity  were  made.    This
data is listed in Table 2.4.  In addition, the solids concen-
tration was determined  on selected  samples.   Lime sludges  in
excess  of  30% solids  were handled  routinely  with an  air
operated diaphragm pump and 3.8  cm  (l*j in.) I.D.  hoses without
difficulties.    Pumping  rates were adjusted  to maintain  line
velocities in  the  1.2 to  2.4 m  per  sec.(4 to 8 ft.  per sec.)
range to prevent settling.   Lower velocities and high  solids
resulted in  occasional line blockages.   However,   the   lines
were easily  flushed  out.   In  a routine  operation  where  the
lime sludge solids concentration could  be controlled at 20  to
30%,  line  blockages should be almost  entirely eliminated.
                              24

-------
                                              WATERPLANT LIME SLUDGE
JO

Ul
       O

       2
       cc
       UJ

       5
GROUND LIMESTONES
          START
                         FINISH
                Figure 2-8: RELATIVE REACTIVITIES OF LIMESTONES AND LIME SLUDGE

-------
                        TABLE 2.2
               LIME  SLUDGE  SLURRY  ANALYSIS
Date/Time
Test
10/28/78 (A)
(B)
(C)
(D)
(E)
(F)
(G)
(H)
(I)
Average values
tests (A thru
tests (E thru




Slurry Solids
CaS04.2H20
CaS03.35H20
CaC03
MgCO3

u^ ft (^ a Crt ^H fi
WC« e wQOWji • *-*l*^V
83.62
88.40
89.12
90.79
90.79
87.44
89.36
84.58
87.12

D) 87.98
I) 87.86
TABLE
LIME AND LIMESTONE
Lime Slurry
May 1976
Wt. %
33.4
54.5
3.7
-
Acid Insoluables 4.6

M f- ft f"*aco l*ir n
w u • T> V»QOx/<2«*2£l*)U
-0-
-0-
-0-
-0-
-0-
1.43
-0-
-0-
-0-

-0-
0.28
2.3
SLURRY ANALYSES
Limestone Slurry
May 1977
Wt. %
77.5
1.0
17.3
0.8
3.4

wt. % CaCO,
	 3
1.59
1.14
-0-
-0-
-0-
2.84
2.05
6.25
2.50

0.68
2.73










TOTAL
96.2
100.0
                         26

-------
                           TABLE 2.4

       LIME  SLUDGE  SPECIFIC GRAVITY AND SOLIDS CONTENT

Date
10/23/78
10/27/78
"
10/28/78
n
n
10/29/78

n
n
10/30/78
n
n
n
10/31/78
n
n
n
11/1/78
n
n

fime
15:40
9:00
16:30
23:10
19:10
6:10
14:10
10:00
2:10
22:10
2:10
6:10
12:00
16:00
8:10
11:40
20:00
15:40
0:10
4:00
8:00
Specific
Gravity

-
-
1.07
1.000
1.064
1.336
1.12
1.072
1.29
1.26
1.26
1.047
1.31
1.21
1.32
1.262
1.085
1.276
1.31
1.3
wt. %*
Solids
(8.86)
(23.32)
(12.82)
10.04
11.8
9.6
40.0
17.0
10.7
35.7
32.8
32.8
7.1
37.6
(24)
38.6
33.0
12.5
34.4
37.6
36.7
Sample
Location
Tank Truck
Thickener u' Flow
n
n
n
n
n
n
n
n
n
n
n
n
27.6
n
n
n
n
n
n
* These values were calculated from the S.G. Data  using  a
  value of 2.7 for the S.G. of the solid phase  and 1.0  for
  the water phase.  The values in brackets  are  moisture
  balance measurements.
                              27

-------
                           SECTION  3

                    SURVEY OF WATER PLANTS

SCOPE OF SURVEY

     There are numerous sources of data regarding water supply
and  use in the United  States.   Two references  which  highlight
major users were  relied upon  for this  survey:

     Public Water Supplies of 100 Largest Cities in the United
     States, 1962.
     Geological Survey Water  Supply  paper No.  1912.

     Operating Data For Water Utilities 1965 to 1970,  American
     Water  Works Association (AWWA)  Statistical Report  No.
     20112.

     These  references were  used  to  identify  major  water
softening plants  using lime-soda ash processes.   In  addition,
a narrowing of the selection was based on the location of high
sulfur coal deposits and  a concentration  of the industry.

     Figure 3-1 illustrates hardness characteristics  of water
supplies  and Figure   3-2  illustrates   the  location  of  coal
resources.   A  comparison  of  these  figures,  points  out  a
somewhat  unique  set of conditions existing in Ohio,  Indiana
and  Illinois.   These  states  have  both  large deposits  of high
sulfur coal  and  relatively high levels of  hardness  in  their
water supplies.   In addition, these states are  highly indus-
trialized  and  are  among  those  states wi/th the  highest  SO-
emissions.  Other states were included in/the survey to obtain
data from areas which  may be  able  to reuse  lime sludge in the
future and  to  get a good  picture  of the variability  of lime
sludge characteristics.

Sources of Lime Sludge

     A survey  of  water   treatment plants  in  the twenty  one
cities listed in Table 3.1 was made.  The  cities were  selected
because they have large water  treatment systems  and  they were
listed as users of  lime  for  water  softening in either of  the
two reference sources  cited above.

     Sixteen of  the  twenty one cities  surveyed  reported that
they were currently using  lime to  soften water and four  said
they were  not.   One of  the  four,  Saginaw,  Michigan,  stopped
using lime after 1975  because of the  cost.   Two of the fifteen
users of  lime  softening recalcine the lime sludge and  reuse
the lime.   The rest dispose of a total  of approximately  3.8  x
10  Mg per year  (4.3 x  10  Tpy) of liiae sludge as solid calcium
carbonate or an average of  2.7 x  10   Mg  per year (3.0  x  10
TPY) for  each city.

                              28

-------
IO
\o
          Figure 3-1
Weighted average hardness, by States and Puerto Rico of water delivered from 1,596 public supplies, 1902.

-------
Ftgur* 3-2:  KEYSTONES MAP OF THE COAL FIELDS OF THE UNITED STATES

-------
                                                                         TABLE 3.1
 Town
             State
Quincy       111
Kankee       111
Pittsburg    Pa
Sag inaw      Mich

Flint        Mich
Hestview     Pa
Coluabus     Ohio
Dayton       Ohio
 Bloonington  Min
 Omaha        Neb
Oklahoma
City
Austin
Dallas
Ft. Wayne
Okl

Texas
Texas
Ind
Des Moines   Iowa

Topeka       Kansas
New Orleans  La
St. Paul     Minn
Kansas City  Missouri
St. Louis   Missouri
WATER PLANT
SURVEY DATA SUMMARY
Water Lime
Line
Softening
Yes
Yes
NO
Stopped
in 1975
No
No
Yes
Yes


Yes
Yes

Yes

Yes
Yes
Yes

Yes

Yes
Yes
Yes
Yes
Yes
Hardness
Hardness Hardness Reduction
In (PPM) Out (PPM) (PPM)
180
300





170
350


314
70 PPM
Reduction
308

(Variable
93
279

350

181
143
175
250
235
112
100





100
150


100


204

for 3
67
86

125

67
113
80
125
110
68
200





70



214
70

104

Plants)
26
193

225

114
30
95
125
125
Treated Consumption
10 I/day 10 Mg/year
Mil Gal/day) TTon/yr)
2.6 - 3.0
3.8





30.
32.


2.
32.

24.

24.
75.
12.

13.

8.
51.
20.
40.
45.





3
2


6
2

2

6
7
5

3

3
1
8
3
4
(7-B) 1.03 (1139)
(10) 1.81 (2000)





(80) 8.28 (9125)
(85)


(7) 2.27 (2500)
(85)

(64) 7.13 (7862)

(65) 9.15 (10083)
(200) 26.93 (29680)
(33) 9.98 (11000)

(35

(22)
(135)
(55)
(106.5)
(120)
Estimated
Dry CaCO
Disposed
10 Mg/year
(Ton/yr)
3.69
6.44





29.





80
(4066)
(7100)





(32850)
None


8.
9.

25.

32.
96.
33.

38.

6.
11.


10
25

49

02
16
84

0

89
16


(8925)
(10200)

(38100)

(35300)
(106200)
(37300)

(41900)

(7600)
(12300)
None
36.
41.
74
37
(40500)
(45600)
Final
Sludge
Disposal
River
Quarry (Pond)





Landfill
All CaC03 is
recalcined back
to CaO
Landfill
Lagoon

Pond

Landfill Very
Lagoon
Lagoon-Landfill

Lagooned
Since 1949
River
River
Sludge
On
Band
None
40 yrs worth
Sanitary Landfill




500 Acre Ft



No Estimate
No Estimate

Removed
Periodically
Large Amounts
6x10 Ft
Removed Period-
ically to Landfill

12' Deep
None
None
Reclined t Reused
River
River
None
None
                                                                                             TOTAL
                                                                                                  3.8 x 108 Kg/Year (4.3 x 105 Ton/Yr)
                                                                                             AVERAGE
                                                                                                                                 (3.0  x  10   TonA')
                                                                                                   (For  14 Cities) 2.7 x 10 Kg/Year

-------
      Lime-sludge  is  usually  disposed  of  in one  of 3  ways;
river dumping,  landfilling  or  lagoon/ponding.   Of  the,.f if teen
cities which dispose of sludge, 5 river dump 1.08 x 10 Mg  per
year  (119,000 TPY), 4 landfill 1.04 x 10  Mg per year (114,400
TPY)  and  5  lagoon/pond 1.75 x 10  Mg per year  (193,300  TPY).
In  the future,  river dumping may  be  precluded due  to environ-
mental regulations.

      In  addition  to  the annual  production of lime  sludge,
existing  lagoons and  landfills at  many  sites  could be  ex-
cavated  to  provide a  substantial increase  in  the  supply  of
lime sludge.  Among the sites  surveyed,  Columbus, Ohio and  Des
Moines, Iowa each have approximately 8 x 10  Mg (9  x 10   T)  of
lime  sludge in  landfills  or lagoons.

      In addition to the cities surveyed, those listed in  Table
3.2 were  identified by  the AWWA report No.  20112  as having
water softening facilities.

     A  breakdown of  total  lime  sludge tonnage by  state  is
listed in Table 3.3.   This  table includes estimated tonnages
determined  by   the  survey and  projected  tonnages  which were
based on  the total  amounts  of water (as listed  in Table 3.2)
softened  in each state.

     The  information  presented in Tables 3.1,  3.2 and 3.3  on
water softening facilities, represent  only  a  portion of  the
facilities  presently   practicing   lime   softening.    Many
facilities do not supply  data  to  the AWWA,  and  the  AWWA  lists
do  not include  captive industrial  facilities.

  _   in the states  listed- in Table  3.2,  an average  of 596  x
10  1 per day (1,574 x 10   gal  per day) of  water was softened
ou£ of a  total  water  usage  of  1,420  x 10  1 per day (3,749  x
10  gal.  per  day).   This water  was  consumed by 25.8 million
persons.   The   total population  of these states in  1970  was
64.6  million  persons .whose total water  consumption was  ap-
proximately 3,554 x 10' 1 per day  (9,426 x  10b  1 per day)  Tf)
if  the  same  proper tioji of   this  water  was  softened,   ap-
proximately 1,491  x 10 1 per  day)  would  have  been  treated.
This  amount  of  treatment would result in  1,816 Mg  per year
(2.0 x 10  TPY  of lime sludge solids.

     The population of the  states  listed in Table 3.2 and  3.3
is  approximately  30%  of  the   total  U.S.  population.   Water
supplied to  the  other 70% of the population  is softened but to
a lesser  extent.   This  softening  results in additional lime
sludge generation.
f 4)
   Based  on  an  average per  capita  consumption  of  146  gal.
per day.

                              32

-------
                            TABLE 3.2

                WATER PLANTS USING LIME SOFTENING
                  AND AVERAGE DAILY WATER RATES
ILLINOIS                 MM gal/Day          107I/Day
     Bloomington             7.36               2.79
     Champaign-No 111.  Wtr  12.53               4.74
     Edwardsville            1.36               0.52
     Jacksonville            3.29               1.25
     Kankakee               10.02               3.79
     La Grange               2.05               0.78
     Moline                  6.04               2.29
     Peru                    1.70               0.64
     Quincy                  7.71               2.92
     Springfield            19.73               7.47

          State Total       71.80              27.19

INDIANA

     Connersville            4.62               1.75
     Fort Wayne             33.00              12.49

          State Total       37.62              14.24

IOWA

     Ames                    3.53               1.34
     Cedar Rapids           17.46               6.61
     Council Bluffs          7.53               2.85
     Des Moines             34.34              13.00
     DuBuque                 6.77               2.56
     Fort Madison            1.51               0.57
     Marshalltovn            3.81               1.44
     Newton                  2.81               1.06
     Ottumwa                 4.30               1.63
     Spencer                 0.94               0.36
     West Des Moines         1.49               0.56

          State Total       84.49              31.98
                              33

-------
                       TABLE 3.2  Continued
     KANSAS
106 Gal/Day
     Chanute
     Coffeyville
     Emporia
     Independence
     Junction City
     Lawrence
     Leavenworth
     Manhattan
     Mission-Johnson County
     Ottawa
     Pittsburg
     Salina
     Topeka
     Witchita
          State Total
LOUISIANA
     New Orleans
          State Total
MICHIGAN
     Ann Arbor
     Bay City
     Iron Mountain
     Lansing
     Saginaw
     Ypsilanti

          State Total
      58
      92
      50
      84
    2.11
    6.33
    3.68
    1.31
   16.28
    1.71
    2.69
    6.11
   22.0
   38.06

  112.12
  135.00

  135.00
   17.40
   11.89
    1.68
   21.92
   28.02
    9.11

   90.02
                10' I/Day

                   0.60
                   1.
                   1,
                   2.
                   1.
   48
  .70
 0.70
 0.80
  ,40
  .39
 0.50
 6.16
 0.65
 1.02
 2.31
 8.33
14.41

42.44
                  34.07
MINNESOTA
     Bloomington
     Fergus Falls
     Moorhead
     Richfield
     Roseville
     St. Paul
          State Total
7
1
3
3
      00
      68
    2.85
      68
      04
   55.13

   73.38
 2.65
 0.64
   08
   39
   15
 1,
 1,
 1,
20.87
                  27.77
                             34

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                      TABLE 3.2  Continued
MISSOURI
     Gladstone
     Kansas City
     Marshall
     St. Louis County

          State Total
10  Gal/Day

    1.64
  106.50
    1.81
  120.00

  226.50
                                             10   I/Day

                                               0.62
                                              40.31
                                               0.69
                                              45.42

                                              87.04
NEBRASKA
     Bellevue
     Omaha
          State Total
    1.60
   85.00

   86.60
                                               0.61
                                              32.17

                                              32.78
OHIO
     Columbus               80.00
     Alliance                5.91
     Ashland                 2.78
     Chillicothe             2.47
     Coshocton               5.19
     Cuyahoga Falls          6.28
     Dayton                 70.41
     Defiance
     Delaware
     Marietta
     Massilon-Ohio Wtr Serv
     New Philadelphia
     Piqua
     Reynoldsburg
     Shelby
     Sidney
     Struthers-Ohio
       Water Serv
     Troy

          State Total
    3.80
    2.06
    3.91
    4.41
    1.85
    3.98
    1.13
    1.32
    2.64

    3.55
    2.47

   204.16
                                              30.28
                                               2.24
                                               1.05
                                               0.93
                                               1.96
                                               2.38
                                              26.65
                                               1.44
                                               0.78
                                               1.48
                                               1.67
                                               0.70
                                               1.51
                                               0.43
                                               0.50
                                               1.00
                                               1.34
                                               0.93

                                              77.27
OKLAHOMA
      Oklahoma  City
      Norman

           State  total
    64.00
     3.65

    67.65
                                              24.22
                                                1.38

                                              25.60
                             35

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                       TABLE 3.2  Continued
TEXAS
     Austin
     Corpus Christi
     Dallas
     El Paso
     Greenville
     Me Allen
     Temple

          State Total
 10° Gal/Day

     50.40
     73.86
    181.68
     62.79
      3.32
      6.99
      5.41

    384.45
              10' I/Day

                 19.08
                 27.96
                 68.77
                 23.77
                  1.26
                  2.65
                  2.05
                145.51
TOTAL FOR ALL STATES
  1,573.79
                595.66
                            TABLE 3.3
                   LIME SLUDGE TOTALS BY STATE
State

Illinois
Indiana
Iowa
Kansas
Louisiana
Michigan
Minnesota
Missouri
Nebraska
Ohio
   Estimated
  Lime Sludge
Mg/Yr (Tons/Yr
10,130
33,840
38,010
 6,900
11,160
(11,166)
(37,300)
(41,900)
(7,600)
(12,300)
 8,100 (8,925)
78,110 (86,100)
 9,250 (10,200)
29,800 (32,850)
              Projected
             Lime Sludge
            Mg/Yr (Tons/Yr
41,020
38,590
93,520
35,140
11,160
17,550
84,880
78,990
 9,450
76,050
(45,220)
(42,510)
(103,090)
(38,732)
(12,300)
(19,354)
(93,560)
(87,070)
(10,392)
(83,833)
                       379,460 (4.3xl05   725,530 (S.OxlO5
                             36

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     Data published in the Lime Chapter  of  the Bureau of Mines
1977 Minerals Year  Book  indicates  that 1.5  x 10  Mg (1,652,000
T) of lime (CaO)  is used for water purification.  Most of this
lime is  used  for  softening of domestic  and  industrial water
supplies.  A conservative estimate of  total annual lime sludge
production based on this lime  consumption figure  is 3.6 to 4.5
x 10  Mg  (4 to 5 million dry  tons) per year.

     This estimate is in basic agreement  with that extraplated
from the data in the AWWA publication as summarized in Tables
3.2 and 3.3.

Characteristics of Lime Sludge

     Lime  sludges  were  obtained from  the  ten municipal lime
water  softening  systems  listed  in Table  3.4.    In addition
samples  from the  water  treatment plant at  Rickenbacker AFB
were  analyzed.   Results  of  the  chemical  and  particle size
analyses  for  these ten  samples are also  listed.

     It can be seen from the data in Table 3.4 that,  with  a few
exceptions  (i.e. St. Louis and New Orleans),  the chemical and
physical  characteristics of  lime sludges are  very similar.
Total alkalinity for the eight samples exclusive of St.   Louis
and  New  Orleans,  ranged  from 74.3  to  96.8%  with an  average
of 89.49%  and an average  hydroxide content of 1.6%.  Acid  in-
solubles  ranged  from 0.13 to  16.0%  with an average of  3.87%.
The mass median particle diameter for the samples exclusive  of
St.  Louis, New Orleans and  Topeka  ranoed  from  2.8  to  10.3
microns  with  an average of 6.71 microns^*'.

     The lime sludge used for the testing at RAFB was  obtained
from the Morse  Road water plant in Columbus.  The  Morse Road
samples  number  20 and 21  in  Table  3.4, had an  average  CaCO~
alkalinity of 88.34% and hydroxide content  of 3.3%,  acid  in-
solubles of 4.29%  and a particle  size of 6.7 microns.

Sjjmmary

      Based on  the  estimated .annual  lime sludge  production
of  1,816 mg per  year (2.0 x 10  TPY),  its proximity to present
or  potential consumers  of high  sulfur coal in the midwest and
 its  relative uniformity  regarding  both chemical  composition
 and  physical characteristics, this  material  has  the potential
 to   supplant or   supplement  other    reagents  at  many  FGD
 installations.
 (5)See Table 3.4
                              37

-------
                                                                       TABLE 3.4
U)
00
  Sample
    No.
12
13
14
15
16
17

18
19
20
21
22
23
     37
     38
        City
St. Paul
Ft. Wayne
RAFB
RAFB
Kansas City
Bloomington
Minn.
St. Louis
New Orleans
Columbus
Columbus
Des Moines
Topeka
        Dallas
        Dallas
LIMB SLUDGE SURVEY SAMPLE ANALYSES

Wt. %
CaS0..2H_0
4.78
1.19
2.39
0.00
0.00
0.00
4.78
4.78
2.39
5.02
4.30
1.43
0.00
0.00
Wt. %
Ca(OH) &
Mg (OH) .
z
0.00
0.00
0.00
0.00
8.71
0.00
0.00
1.87
3.11
3.58
4.36
0.78
0.00
0.00

Wt. %
CaCO
^
81.87
76.42
78.45
80.51
56.40
82.56
23.88
61.29
83.47
73.91
74.82
82.44
76.53
86.65

Wt. % Acid
Insoluables
0.13
4.64
0.36
0.22
6.97
0.23
61.26
21.14
2.07
6.51
2.16
5.64
16.08
1.41

Alkalinity
as CaCO,
91.31
74.30
96.06
92.23
90.30
95.54
24.33
67.16
92.32
84.36
94.28
86.55
79.80
96.81

Wt. %
Ca
33.24
38.89
25.55
28.77
27.00
40.95
11.33
25.39
26.47
23.81
31.82
63.17
29.20
32.77
                                                                                      Wt.  %
                                                                                        »9
Wt. %
so -
                     Mass Median
                     Particle Size
                       Microns
91.31
74.30
96.06
92.23
90.30
95.54
24.33
67.16
92.32
84.36
94.28
86.55
33.24
38.89
25.55
28.77
27.00
40.95
11.33
25.39
26.47
23.81
31.82
63.17
2.25
2.34
2.29
2.02
8.29
2.33
0.73
1.99
1.71
2.74
3.97
1.95
0.46
0.52
0.87
3.34
1.49
0.16
0.37
1.75
0.20
1.01
0.67
2.75
0.14
0.11
0.08
0.28
0.22
0.23
0.27
0.28
0.28
0.23
0.17
0.17
10.2
Dry
3.2
39.5
4.2
47.5
47.1
0.10
8.8
70.6
6.7
0.10
9.2
2.8
7.9
9.8
10.3
6.0
18.0
*
6.8
6.5
6.0
*
                                                                                        0.32
                                                                                        1.57
1.29
1.54
0.07
0.08
53.2
40.5
3.6
4.95
                                                                             * These samples were too dilute  to obtain sufficient solids  for
                                                                               particle  size determinations.

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                          SECTION 4

             PROPOSED  LIME  SLUDGE HANDLING SYSTEM

     The handling  of  lime  sludge  is  a familiar operation at
many water plants, and periodic  lagoon emptying is practiced
at many sites.

     The  lime  sludge  samples  obtained  in  the  water plant
survey  and  other data     indicate  that  lime  sludges can be
dewatered with  proper  lagoon operation  to 50% solids.  This
material can be handled with conventional  earth moving equip-
ment and transported by truck.

     The  specifications  listed  in  Table 4.1  define design
criteria  for  a proposed lime  sludge  handling  system.   This
system  is suitable for the  R-C Banco System at  RAFB or for  any
other 2 to 4% sulfur  coal fired boiler with a gross heat input
of 2.1  x 10  kj per hour (200 mm BTU  per  hour).

LIME SLUDGE HANDLING SYSTEM DESCRIPTION

     The  lime  sludge  handling system at the water  treatment
plant disposal site will  require only a front-end loaderfiand  a
gasketed dump  truck, similar  to  those currently  in use^   ,  to
transport dewatered  lime sludge.   The front-end  loader will
scoop  the  dewatered  lime  sludge  at  50%  solids  concentration
from the lagoon and deposit  in  into the  dump truck for trans-
port to the boiler location.   Careful lagoon management is  es-
sential to  achieve a  50%  solids  concentration.    The  lagoon
supernate  or   accumulations   from  heavy  rainfall  must   be
decanted  from  the  lagoon prior to  each  fresh  sludge  applica-
tion  and  at  no  time  should  ponding  of  the  supernate  be
allowed.  This is necessary because submerged lime sludge will
dewater to  only  about  30%  solids.   Providing  lagoon  under
drains  is  recommended as  the  most reliable method  to reduce
the water content to consistently produce a 50%  solids sludge.

     The  lime  sludge  handling system at  the boiler  site,  il-
lustrated  schematically  in  Figure  4-1,  will  consist  of  a
sludge  storage  area,  a  front-end  loader,  two  mixing  and
storage tanks  each  equipped  with  a feed  hopper and  screw
conveyor,  and two independently  operated slurry  feed pumps.
Plan  and  elevation  views of  this  equipment  are  shown  in
Figures 4-2  and  4-3.    This  system  utilizes  below  ground
concrete  storage  and  mixing  tanks.
            AWWA October 1975
 From Lagooning  to  Farm Land  Application G. Russel,  Pg.  585
 and  AWWA Research  Foundation August  1969,  Page  54,  Program
 Number  12120ERC
                              39

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                          TABLE 4.1

         LIME SLUDGE HANDLING SYSTEM DESIGN CRITERIA

I.   Water Plant Disposal Site Specifications;

     1.   Average rate of lime sludge removal 13.6 Mg per day
          (15 tons per day) dry solids as calcium carbonate.

     2.   Type of lime sludge disposal site:  Lagoon
          without substantial surface evaporation.

     3.   Dump truck transport.

     4.   Weekly removal.

     5.   Loading equipment
          Front  end  loader or  equivalent to be  supplied by
          water plant operator.

     6.   All equipment  to  be designed  for outdoor operation
          in midwest climate.

II.   Lime Sludge User site Specifications;

     1.   Average rate of lime sludge use;

          13.6 Mg per day (15 tons per day) dry solids diluted
          to 25% solids for use  in the SO2 scrubbing system.

     2.   Type of lime sludge storage: 95.3 Mg
          (105 ton)  (at 100% solids) one week supply dump pile
          with  suitable   mixing  and  dilution  equipment  to
          prepare 25% solids.

          NOTE;   Front  end loader or equivalent to be supplied
          by scrubbing system owner.

     3.    Unloading  equipment:

          Dump truck  unloading to be accomplished without as-
          sistance of plant operating personnel.

     4.    All equipment  to be designed  for outdoor operation
          in midwestern climate.
                            40

-------
• LIME SLUDGE STORAGE AREA
FRONT END LOADER
. MIX TANK
                                   SCREW
                                   CONVEYOR
                                       FEED
                                       HOPPER
                                                          SLURRY RECYCLE
                                                          FROM FGD SYSTEM
                                  TO FGD SYSTEM
                                  SLURRY
                                  FEED
                                  PUMP
     Figure 4-1:  LIME - SLUDGE HANDLING SYSTEM

-------
to
                                                      PADDLE MIXER
                                                    HOPPER LOADING
                                                    AREA
                             • STORAGE AREA DRAINAGE
                              TRENCH WITH GRATING
                              LIME SLUDGE STORAGE AREA
                                                                                     MIXING AND STORAGE
                                                                                     TANK NO.1 (CONCRETE)
                                                                                                                DENSITY METER (TYP.2 PLACES)



                                                                                                              /- CONTROL VALVE (TYP 10 PLACES)

                                                                                                                  LIME SLUDGE SLURRY PUMPS
                                                                                                              /- (TYP.2 PLACES)       RECYCLE WATER
                                                                                                                            2." CU   FROM SCRUBBER
                                                                                                                                        TO SCRUBBER
                                                                                                                           I'/z" US
                                                                                                                                         - pH CONTROL VALVE
                                                                                                                      LSS = LIME SLUDGE SLURRY
                                                                                                                      CW = MAKE-UP WATER
                                                              Figure 4-2: LIME SLUDGE HANDLING SYSTEM -  PLAN VIEW
                                                                                      scoit*r>

                                                                                                       iQ'- o-
                                                                                                   On original

-------
CW
(FOR SPRAY
DOWN)
                                                                                WALKWAY WITH RAILING
                                            CW MAKE UP WATER LINE
              SLUDGE HOPPER


                    60
                                                      MAX
                                                      SLURRY
                                                      LEVEL
                                                           PADDLE MIXER
                                    MIXING AND STORAGE
                                          NO. 2
                                     LIME SLUDGE TANK
HOPPER
SUPPORT
                                                                                   CW SPRAY WATER LINE
    LIME SLUDGE
    SLURRY PUMP
    NO. 2
          SLURRY WITHDRAWAL LINE
                                                                           SCREW CONVEYOR
SCREW CONVEYOR
SUPPORT
                  Figure 4-3:  LIME SLUDGE HANDLING SYSTEM
                                                                                    SLUDGE HOPPER
                                                                                      SECTION BB
                        SECTION. AA
                        SCALE: %" m 1-0'
                                                     ON ORIGINAL

-------
     The  system is designed  to  receive 50% lime sludge,  re-
slurry  it  to a 25% solids concentration,  and  feed  it to  the
PGD  system.   A lime  sludge  storage  area is provided  to  hold
one  week's  supply  of  50% sludge at a utilization rate of  ap-
proximately  13.5  Mg  (15 tons)  of  dry solids  per  day.    The
storage area  is surrounded  on three sides by a 0.6 m  (2  ft.)
high retaining  wall and has  a trench with a sump pump on  the
ot/en side  to  collect  any water which drains from the  sludge.
The  two mixing and storage tanks are provided with paddle  type
mixers.   Each tank is  sized  to  hold one day's supply of  25%
solids so that while one tank is reslurrying the other  will be
feeding the  scrubber.   Two  air  operated diaphragm pumps  are
also provided to pump  the 25%  slurry to the  scrubber.

     The system is designed to be controlled from both  a local
control panel by  the  front-end  loader  operator and from  the
FGD  system  control  panel.     During normal  operation,   both
paddle mixers and feed  pumps  will  operate continuously.    in
the  tank  which  is being used  to  feed the scrubber, the  pump
discharge control valves will be set to deliver the  full 130 1
per  min.   (35  gpm)  pump  output  to  the  scrubber  area.    An
automatic pH control valve at the scrubber will allow approxi-
mately 25 1  per min  (7 gpm)  to be fed  to the  scrubber system
while  the  remaining  105 1 min  per  (28  gpm) will be recycled
back to the feed tank.   This procedure maintains a 1.2  to 2.4 m
per  sec.  (4 to 8fps) velocity  in  the 3.8  cm  (1*5  in.) feed  and
recycle lines.  A level probe in the feed tank  will  signal  the
FGD  system  operator when the slurry level is at a  low level.
At this time  the  operator  should energize the pump discharge
control valves  so that  the  pump for the second storage  tank
feeds  the  scrubber  system and the first  pump  is in the  full
recycle mode and is returning the full 130 1 per min.  (35  gpm)
into the  mixing tank.   A  new batch  of sludge should now  be
prepared  in the first  mix tank.

     When  preparing  a  fresh batch  of  slurry, the front-end
loader operator first  turns  on  the appropriate  screw conveyor
and  opens  the automatic  control valve  in  the make up water
line.  This valve will automatically close  when  it  receives a
signal from the tank level probe indicating that approximately
80% of the water required to prepare one  batch  has  been added
to the tank.  The front-end  loader operator  then  dumps a  pre-
determined  number of   buckets  of  the   50%  sludge  from   the
storage area into the appropriate tank hopper.   This sludge is
fed  into  the  tank  center at  a  constant rate  by  the screw
conveyor.    Finally the front-end loader operator  opens  the
automatic  valve on the make-up water  line  which  washes  the
sludge remaining in the hopper into the tank.  This  valve  will
automatically close when it  receives a signal from the  density
meter  located in  the  pump  recycle  line  indicating that  the
sludge  is  at the  desired 25%  solids concentration.   if  ex-
cessive 50% sludge was added so  that the  25% concentration is
not  achieved, a high  level signal from the level  probe  also
closes this valve to prevent the  tank from  overflowing.
                              44

-------
     In the event that the FGD scrubber system is not operat-
ing for a  period of  time,  a  flushing system  is  provided to
wash the slurry  out  of  the  pipes and pumps.   By manipulating
the manual valves  on the  pump  suction,  the solids  can be
flushed either back into the mix  tanks or  through  the pumps to
the scrubber system.

     An equipment  list  and  preliminary capital cost estimate
are presented in Table 4.2 for the equipment  described  above.
The total  capital  cost  for  this system, which includes  below
ground  concrete  tanks,  was  estimated  to  be approximately
$100,000.

     The system  as proposed provides 100% redundancy  for all
major equipment items.  If an  existing reagent system could be
put on standby operation when a lime sludge system is added  to
the facility  the redundancy could  be eliminated.   This  would
result  in  a  cost  saving of  approximately  40%  for the  lime
sludge system.
                             45

-------
                          TABLE 4.2

           LIME SLUDGE HANDLING SYSTEM COST SUMMARY


                Sludge Feed  System at Boiler -
 Equipment and Materials List  and Construction Cost Estimate


                                           Installed
Equipment and Materials                 Cost Estimate

Mechanical Process Equipment

     2 - KW  (20 Hp) Paddle Type Mixers     $20,000

     2 - 0.15 M (6")  x 4.6 M (15') Screw
         Conveyors                          8,000

     2 - 130 1/min (35 gpm) Air Operated
         Diaphragm Pumps                    4,000

     1-60 1/min (15 gpm) Sump Pump        1,500

     2-  4.9 m (161)  diam x 3 m (101) high
         inground concrete tanks            8,500

     2 - 2.4 m (81) x 1.7 m
         (53s1 ) x 1.5  m (5* ) steel
         sludge hoppers                     3,000


               Sub Total                   $45,000
Other Materials Including                 $34,370

     Piping
     Instumentation
     Sludge Storage
     Access & Supports
               Sub Total                  $79,370

Contingency (25%)                         $19,850


     APPROXIMATE TOTAL COST               $99,220
                               46

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                          SECTION 5

            ECONOMICS OF  LIME  SLUDGE UTILIZATION

     One of the most important objectives of this program was
to determine the economic  viability of  using lime sludge as an
alternate PGD  scrubbing reagent.   This section presents both
the economics of lime sludge utilization  and  a comparison of
these costs with those for lime and limestone.

     For  this  economic evaluation an industrial  coal fired
boiler  with an FGD system having  a 180,000 Ib per hour steam
generating capacity will  be used.   A  plant operating  rate of
751 was  selected and  a  typical midwestern coal with a 2.33  x
10  kJ per Kg  (10,000 BTU per  Ib)  heating value and  3% sulfur
was selected as the fuel.   Approximately 5.4 x 10  Mg  (60,000
tons)  of coal  would  be  burned  annually.    An  SO2  removal
efficiency  of  80%  is  required  to  limit SO2 emissions  to  less
than 0.516 mg per kJ  (1.2 Ibs  per  mm BTU) of coal  fired.

     Based on the above requirements,  the  reagent consumptions
listed in Table 5.1 are necessary.

LIME SLUDGE SYSTEM OPERATING COSTS

     The  operating costs  for  a lime  sludge handling  system
include  utilities,  operating  and maintenance labor  and  over-
head, depreciation, taxes, insurance and the cost of  obtaining
the lime  sludge.
made:
     For  this analysis  the following  assumptions have  been
     1.   The  lime sludge is available  within  a fifteen mile
          radius  of  the  FGD  system.

     2.   Lime sludge will  be  transported  in  gasketed dump
          trucks  owned and operated by  a  local  trucking con-
          tractor.

     3.   One  eight-hour  day  of hauling per  week will  be
          needed  to  transport lime sludge from  a  local water
          treatment  plant to the FGD system using two trucks.

     4.   The  water  treatment plant  will load lime sludge into
          the  trucks  at  no charge for  the  sludge  or  for
          loading.

     5.   The  truck  operator  will  unload  at  the  FGD site
          without assistance from plant operating personnel.
                              47

-------
                          TABLE 5.1

                REAGENT REQUIREMENTS AND COSTS

          10  Mg/Year                    Reagent-S02  g
          (Tons Per Year)     Purity    Stoichiometry —
Lime         2.54  (2800)       90%           0.8
Limestone
90%-74
microns
(-200 mesh)  5.37  (5920)       95%           1.0
Lime sludge  4.70  (5180)       90%           0.84
                         Estimated
                       Delivered Cost
                           Per Ton           Annual Cost

Lime                       $42.00             $117,600
Limestone                  $13,00             & 77,000
                          TABLE 5.2

          INCREMENTAL OPERATING COST FOR LIME SLUDGE
                      UTILIZATION  SYSTEM

Capital Cost                       $100,000

Power 128,000 KWH @ $0.25/KWH                    $ 3,200
Water no additional cost
Operating labor 800 manhours @ $8.00 per hr.       6,400
Supervision 200 manhours @ $10.00 per hr.          2,000
Maintenance labor & materials 3% of capital cost   3,000
General overhead 75% of operating labor            6,300
Depreciation 10 year straight line                10,000
Texas & insurance 2% of capital cost               2,000
Lime sludge transportation                        22,000

                         TOTAL ANNUAL COST       $54,900

Total lime sludge 4.7 x 10  Mg  (5180 tons) per year dry

Total cost per Mg of lime sludge $11.68  ($10.60 per ton)
                                4
Total coal consumption 5.44 x 10  Mg (60,000 tons) per year

Total cost per Mg of coal burned $1.01  ($0.92 per ton)
 Based on available alkalinity
                           48

-------
     Based on the above assumptions which allow an hour and a
half  for  handling  each  load  of  lime   sludge  and  current
trucking costs  obtained  from a trucking  contractor  in Ohio,
lime sludge transportation will cost  $22,000  per  year.   This
is based on a cost of  $220  per day per truck and fifty days of
hauling per year.

     The anticipated operating costs  for  lime sludge utiliza-
tion is summarized in Table 5.2.  The annual cost savings for
lime sludge when compared  to those for lime and limestone as
listed in Table  5.1 above, is $62,700  per year when compared
to  lime and $22,100 when compared  to limestone.

     It is important to note that  in this  analysis no value is
given to the lime sludge.  In actual  practice lime sludge has
a  substantial  negative value  to  most water  plant operators
because of disposals costs.

     Based  on   earlier   estimates * '  the  cost  of   lagoon
disposal of lime sludges was $5.50 to $18.60 per Mg  ($5  to $16
per  ton)  of  dry solids in  1969.   Current disposal costs are
estimated  to be $11 to $22  per Mg  ($10 to $20 per ton)  based
primarily  on increased labor  and  sludge lime  removal costs.

     The cost savings cited above  represent the  minimum reduc-
tions available  since the negative value of the sludge  has not
been considered.   Given  these conditions in a captive  situa-
tion  such  as the one  at  RAFB, where  they  have both a  water
treatment  plant producing  lime sludge and a FGD system,  full
credit  for lime sludge disposal should be considered.

     If  an $11  per Mg  ($10  per  ton) credit  was  applied to  the
case  described   above  the  annual  cost would  be decreased  by
over $50,000. This would  result in actual savings  of approxi-
mately   $113,000 when  compared   to  lime  and  $72,000  when
compared  to limestone.
 *  'Disposal of water from water treatment  plants AWWA Research
 Foundation  Program No.  12120  ERG,  August,  1969,  Appendix
 Cost Analyses.
                              49

-------
                          SECTION 6

                         CONCLUSIONS

     Based  on the  results  obtained  in this test program
for inlet S02 concentrations in the range of 300 to 500 ppm,
the following conclusions can be drawn:

     Lime sludge, when used as an FGD reagent,  exhibits the fol-
     lowing properties:

          1.   S02 removal  capabilities and  utilization  are
               similar to lime  up to a stoichiometric ratio of
               approximately 0.8.

          2.   Above a  0.8  stoichiometric ratio  SO-  removal
               capabilities and utilization begin to decrease
               toward values typical of limestone.

          3.   The composition of  the  reaction products when
               using  lime   sludges  are   similar  to  those
               obtained with limestone, that  is, they are high
               in gypsum (CaSO4.2H20)  content.

     Based on present handling practices, lime sludges can be
     preapred  for  transport to  FGD  system  use points  by
     careful management of existing lime sludge lagoons and by
     using conventional dump trucks with minor modifications
     to minimize water leakage.

     Lime sludge is available at many water treatment facili-
     ties in the midwestern  states as  well as in  other loca-
     tions in the united states.

     Projected survey  results  indicate  that 18.16 x  105 Mg
     (2,000,000 tons)  per year of lime sludge may be available
     in Midwestern and  Central States.  The Bureau of Mines
     data on lime consumption,  supports this conclusion.

     Lime  sludges  from  different  geographical  areas  are
     similar in composition, alkalinity and particle size.

     Lime Sludge can be pumped with conventional slurry pumps
     at solids  concentrations  in  excess of  30%  by wt.  and
     alternate transportation by tank  truck  at 30% solids is
     feasible.

     A lime  sludge  handling system for  a  typical industrial
     sized FGD installation is approximately $100,000.

     Annual costs for  lime  sludge for a typical Industrial FGD
     system are $55,000 without credits  for  lime  sludge dis-
     posal costs.
                             50

-------
Lime sludge costs for  a typical  Industrial FGD System are
$62,700  less   than  lime  costs  and  $22,100  less  than
limestone.   Lime sludge disposal credits would result in
additional savings of approximately $50,000 per year.
                         51

-------
                          SECTION 7

                       RECOMMENDATIONS

     The results of this lime sludge utilization  test program
are  very  encouraging.   Two significant  problems associated
with the  protection and preservation  of  our environment are
addressed; the disposal of  water plant  wastes and  the costs of
operating an  FGD system.   The  integrated  solution  to  these
problems suggested by  this  study; the reuse  of a waste product
(lime sludge),  is  one of  the most  desirable ways to address
our environmental problems.

     Several  additional steps  are recommended   in  order to
fully implement lime sludge utilization.  These include:

     A  long  term test at RAFB  or  some other facility to de-
     termine the long  term effects of  using  lime  sludge  in an
     FGD system.

     An expanded survey of lime  sludge  sources  to include
     captive   industrial   and   utility    water   treatment
     facilities.

     An evaluation of  the use of lime sludge as a  supplemental
     reagent in existing utility FGD systems.

     Testing of  lime  sludge as  an FGD  reagent at S0_ concen-
     trations in the 1000-2000 ppm range to  define sol removal
     capabilities, reagent utilization and FGD sludge charac-
     teristics.
                             52

-------
                         APPENDIX A

          CONVERSION FACTORS:  BRITISH TO  SI UNITS
To Convert Form
LENGTH
     Inch (in)
     foot (ft)
     miles (mi)
AREA
     inch'
     foot'
VOLUME
MASS
inch3 (in3)
foot, (ft,)
foot" (ftJ)
gallon (gal)
gallon (gal)
     ounce  (oz)
     pound  (lb)
     pound  (lb)
     grain  (gr)
     Ton  (T)
PRESSURE
          To
        meter  (m)
        meter  (m)
        kilometer  (km)
meter
meter
                  2
                m 1
                 (mz)
                         meter- (m,)
                         meter  (m )
                         liter  (11
                         meter  (m  )
                         litre  (1)
         kilogram
         gram (g)
         kilogram
         gram (g)
         megagram
          (kg)

          (kg)

          (Mg)
     Inches W.C.2(in w.c.)kilopascal  (kPa)
     pounds/inch   (psi)    kilopascal  (kPa)
TEMPERATURE
     degree
     Fahrenheit
     degree Rankin
(°F)0
   (  R)
degree centrigrade
degree Kelvin ( K)
ENERGY
     British Thermal Unit
            (Btu)
     British Thermal Unit
            (Btu)
         joule (J)

        "kilojoule (kj)
                    Multiply by
                    2.540x10
                    0.3048
                                                     -2
                                        6.45x10*
                                        9.290x10
                            -2
                             1.639x10
                             2.832x10
                             28.32
                             3.785x10
                             3.785
                            -5
                            -2
                            -3
                                        2.835x10
                                        453.6
                                        0.4536
                                        6.480x10
                                        0.9072
                             0.2488
                             6.895
                                                     -2
                            -2
                     C)   tc
                    0.5555
                                                  9  (fcf~32)
                    1055.

                    1.055
                             53

-------
 POWER
British Thermal
     Unit/hour

     (Btu/hr)
British Thermal
     Unit/hour
     (Btu/hr)
British Thermal
     Unit/horsepower  (hp)

DENSITY

     pound/foot3 (lb/ft3)
     pounds/gallon (Ib/gal)
VISCOSITY

     pound foot ,,
     second/foot   9
     (Ib. ft/sec ft*)

MISCELLANEOUS

     cubic
     feet/minute (CFM)

     gallons/1000 ft3
       (gal/M)

     gallon/minute
       ( gal/mi n)

     grains/standard
       cube foot
       (gr/SCF)

     feet/second
       (ft/sec)
watt  (w)


kilowatt  (kw)

kilowatt  (kw)
pascal-second
   (Pas)
meter_/hour
   (nT/hr)

liter/meter
       j
litre/minute
   (1/min)
                    0.2931


                    2.931x10

                    0.7457
-4
kilogram/meter      16.02
   (kg/in3)

kilogram/meter      119.8
   (kg/nT)
                    47.89
                    1.699


                    0.1337


                    3.785
grams/normal meter  2.288
   (g/nmj)
meter/second
   (m/sec)
                    0.3048
     pounds/1,000,000 Btu
       (Ib/MM Btu)

     British Thermal
       Units/pound
       (Btu/lb)
milligrams/
kilojoule (mg/kJ)
                    0.4299
kilojoule/kilogram  2.326
   (kJ/kg)
                             54

-------
                          APPENDIX  B



               ANALYTICAL AND  TESTING  METHODS








B-l  Thermogravmetric Analysis



B-2  Analytical Procedure for S02 Wet Tests



B-3  Analytical Methods
                             55

-------
                         APPENDIX B-l

             THERMOGRAVIMETRIC ANALYSIS OF SOLIDS
                 FROM BAHCO SCRUBBING PROCESS

General Procedure:

     All  analyses performed  on  lime-based  scrubbing  solids
from  the  Banco S02  Gas Removal  Process  at  Rickenbacker Air
Force  Base utilized  the specific  technique of  thermogravi-
metric  analysis  (TGA).   This  technique  involved  heating  a
prepared  sample of  solid  phase material  at a specific  rate
over  a pre-determined  temperature  range and  observing  the
weight change  which  results from solid state  reaction  occur-
ring at some characteristic temperature.

     After  in-laboratory  treatment,  which includes drying  at
30°C for  24 hours, breaking up the dried solids  and  riffling
as many  times  as  needed to obtain a representative sample  of
about  2.5  gms.;   the  prepared  solid  phase sample  is  then
subjected  to  analysis  on  the  thermobalance over a  pre-pro-
grammed  temperature  range,  (ambient to  980  C)  at a  specific
heating rate (80°C per minute).  The resulting thermogram will
exhibit, in a general case,  associated  weight losses of  waters
of hydration from  CaSO..2H90(130-200 C), % water of hydration
from  CaS03.35H-0( 400-450 °C),  dehydration  of  Ca(OH)~   (575-
625 C),  loss  on  ignition  from  combustibles (700-75C
-------
As  the  sample digests  in the  acid  medium,  C02  and  S02 are
evolved and forced through the  train by a stream of nitrogen
gas.  The evolved C02  and SO2  gases  are passed through a gas
washing bottle fillea with a  30%  hydrogen peroxide solution,
which traps  any  S02  forming H^SO..  The  SO,  free gas stream
then passes through several moisture  traps  (P2°s and anhydrous
magnesium perchlorate) to a preweighed Miller Bulb containing
20 mesh Ascarite,  to absorb the C02.

     After  the digestion has  been  completed,  the  reaction
flask solution is tested  for  insolubles,  calcium content  by
EDTA  titration  (also  magnesium  content   if  applicable) and
total sulfate  by gravimetric means.  The solution  in  the  per-
oxide  trap  is  titrated  for  SO,  using  a BaCl-  titrant and
Thorin as an  indicator.   The Miner  bulb  is weighed  to deter-
mine  the  weight of C02  absorption.   From data obtained  from
these tests we are able  to perform a complete  analysis of all
the constituents  previously mentioned.  Data obtained by this
procedure match TGA results within + 5  percent  in all samples
tested.

      In addition  to the  use of wet chemical methods to verify
TGA data, the use of  laboratory prepared samples using reagent
grade chemicals  similar  to those to be determined  were also
tested  by thermal means.  Various  ratios of CaSO.. 211,0  to
CaSO-.JjIUO  with  amounts  of  CaCO- and  MgCO-were  analyzed  by
TGA.  The  data obtained from  these  TGA analyses  also yielded
results which were  within + 3  percent  of  the  calculated per-
centages  in  the  sample  formulations.

      Use of  a thermogravimetric balance for  lime or limestone
based solids  analysis  is a rapid,  reliable method for the de-
termination   of  CaS0..2H20,   CaSOg.ljH-O,  Ca(OH)2,  MgC03  and
CaCO.,.    The  use of  this  instrument  with  occasional  wet
chemical methods  produces data which is within + 3 percent  of
other  accepted analytical methods and  in substantially less
time  than  comparable  wet chemical analyses.
                              57

-------
                         APPENDIX B-2

            ANALYTICAL PROCEDURE FOR SC>2 WET TESTS

     This  method  for  determining   the  SO-  content  of  gas
streams is only approximate and should be used only as  a semi-
quantitave check on S0~ concentrations.

     No temperature or  pressure corrections have been incor-
porated, and the method should  not  be  used  below  100 ppm.
Apparatus:
                           Reagents:
1)  250 ml impinger with an open 1)
    glass dip tube.              2)
2)  A dry test meter             3)
3)  A source of vacuum
4)  25 ml pipette
5)  Vacuum tubing
6)  Hose clamp
                              3% Hydrogen Peroxide
                              0.1N NaOH or 0.01 N NaOH
                              Methyl/Orange-Sylene
                              Cyanol indicator
Procedure:

     Inlet Samples (i.e., 500 + ppro SO,) pipette 25 ml of  0.1
N NaOH into the 250 ml impinger,  add  50ml  of  3% hydrogen per-
oxide.   Add  approximately  25 ml of  deionized water.    Add
several drops of Methyl/Orange-Xylene Cyanol  indicator.

     Draw  the  gas  sample through  the  impinger  at 0.1 to  0.2
ft./min.   Record  the  gas meter  reading  when  the indicator
turns from green to purple.

     Outlet  Samples   (100  to  600 ppm  SO~ )  substitute  0.01
normal  NaOH  from  0.1  normal  NaOH  in  the  above  procedure.
Follow the same procedure as above.

     The folloiwng equation can  be used to calculate the  SO2
concentration:

     cn  nnm   10,000 x  (NaOH Normality)
     SU2 ppm =      Meter Volume  ft.
 Add the  indicator within  15  minutes  of  running  the
If the  indicator is added  at an earlier  time,  it may be
Note;
test.
destroyed by the hydrogen peroxide in the  impinger.
                             58

-------
                        APPENDIX B-3

                     ANALYTICAL METHODS

     Listed below are various physical and analytical methods
which were  employed in  testing  samples  from  the BAHCO  GAS
Cleaning Project at Rickenbacker  Air Force Base:

Particle Size (Sub-Sieve)  - BAHCO micro-particle classifier as
per ASTM procedures

Particle Size (Sieve) - U.S.  Standard Sieves as per ASTM pro-
cedures

Specific  Gravity Determination  -   Use  of  calibrated cement
pycrometer and ASTM procedure

Bulk  Density -  Use  of  ASTM  procedure  for  compacted  bulk
density

Thermo-Gravimetric  Analysis  -  Used  in  analyzing solids from
scrubbing process; limestone and lime samples  for CaS04.2H20,
CaSO-.JsH-O and Mg(OH),, MgCO,,  CaC07 and loss on igniti&n (see
detailed description Supra.)

Total Sulfate  Analysis - Standard  gravimetric procedure  for
total sulfate measurements.  Ref.  Scott's Standard Methods of
Chemical Analysis.

Total Calcium and Magnesium Content - Normal atomic absorbtion
procedure using  a Jerrell Ash 850 AA  instrument

Alkalinity  Determination  - Conducted  as  per  Thiocyanate-
Ferric  Alum(volhard method) procedure  outlined in  Standard
Methods of Water and Wastewater Analysis

Coal Analysis -  Methods as per those  specified by U.S. Bureau
of  Mines publication  PB-209-036.    Instrumentation   used  for
various tests are as follows:

     Percent Sulfur  in  coal  - Leco  Sulfur  Analyzer
     B.T.U. Values  - Parr Calorimeter
     Percent Carbon, Hydrogen, Nitrogen,  -  Perkin Elmer
     240-Analyzer

Trace Elemental  Analysis - Methods used  to  determine concen-
trations  of  Hg, Cd,  Pb  and  Cr   were  derived  from Varian
Techtron  publication 85-100224-00  and  Jerrell Ash  reference
material  dealing with  flameless  Atomic Absorption  Spectros-
copy.  Methods from these sources were employed in conjunction
with    a    Model   850   Jerrell   Ash   Atomic   Absorption
Spectrophotometer

                              59

-------
    APPENDIX C




SCRUBBER TEST DATA
   60

-------
99.8



99.5


 S3



 91





 S5




 9C





 BC







 6(


 BO



 40



 30



 ZO
      J?6L 739.7H
                                    SWK-


                                                        efe
r?A//


      if
   —Prrejr Fa
cl^3
                                •
                                       '



                   >*?/
                                                    ©
                                                                      i|U


                                                                      ^_i£J


                                                                           ±
                                                                         •

                                                                    L
                                                                            ' -
                                                                                     r


10
                  i-]


                   Jd

                       T"

                                                             -

                                                                                                        -i

                                     1
 2



 1



0.5



0.2


0.1

            -

                                                                       .

                                                -

                            illJ





                                                                                   u..;
                                                                                   fffl

                                                                           —
                                                                                                       —2

         _





                                               ..

                                                           I
                                                                 n

                           J^sf
                            ^y^
                                                                                /??
                                                                                            i  »
                                  1C
                                                                                          1—3

                                                                                        iccc

-------
to
  -4
   0)


   O
99.9



99.8





99.5




 99




 98







 95






 90








 80





 70




 60




 50




 40




 30





 20








 10
            K£^
331
                  	I
                                -4-H
       2




       1




      0.5





      0.2



      0.1 i
                            _i_.
      Jd
        w
        mi
                 "iX
              - t ^Kt-4
                                  X
                                    0
                           Jfit'i
                                                         f   S ' 6
                                                                'f A i I
                                                  t~T


                                                   i  i



                                                   :  t
                                                	^..


                                                 0 i
                                     iJ--r..L-H-
:         I


(BAlHc&y.
[  ' i.-3
!

!  i i-
                                                                                  _L_~
                    /_l_LLi_.
                       III
                                                      ?  f  .r
                                                                             T^-r
  "T
                                                                   ^—
                                                                                            LI..
                                                                                    —f-
                                                                              .0
                                                                        2   i •  a
                                                                                                    + 1
                                                                                                ,.i
                                                                                                  H  o
                                                                               4-
                                                                                                -_U-
                                                                                            I  i
                                                                                                    	4
                                                                                    ?  ?
                                     t0  O r  ,   K-    -         ICC
                                          \a\r\/c/e  OiQ^ei^h,^
                                                                                 	3



                                                                                 •t" C

-------
SCRUBBER TEST DATA
Scrubber
Inlet GAS Flow Lime
Date
11/1/78
11/1/78
11/1/78
10/31/78
10/31/78
10/31/78
10/31/78
10/31/78
10/31/78
10/30/78
10/30/78
10/30/78
10/30/78
10/30/78
10/29/78
10/29/78
10/29/78
10/29/78
10/29/78
10/29/78
10/28/78
10/28/78
PH
Time
4:00
8:00
0:10
15:40
20:00
11:40
8:40
4:10
0:10
20:00
16:00
12:00
6:10
2:10
22:10
2:10
18:10
14:10
Day Shift
6:10
19:10
23:10

Temp. To Scrubber Sludge
-F ^C SCFM NM^/hr PH
300
325
315
300
300
325
348
315
330
320
305
338
340
330
340
342
-
325
330
340
300
330

44,000
44,000
45,000
45,000
45,000
44,000
41,050
37,000
33,000
38,000
40,000
37,500
27,000
27,000
32,000
37,000
43,000
44,500
44,000
38,000
45,000
-

10.7
10.7
10.7
10.7
10.3
10.6
10.6
10.7
10.7
10.7
_
10.7
-
10.7
10.5
10.5
10.6
10.4
10.7
10.6
_
10.6

Scrubber
Ph
6.0
6.0
6.4
6.1
6.3
5.95
5.9
6.0
5.9
6.1
5.95
6.0
3.5
4.8
3.7
4.9
4.0
3.4
4.4
4.5
4.9
4.9

Dissolver
PH
6.2
6.0
6.15
6.3
6.45
6.25
6.1
6.4
6.15
6.2
6.1
6.2
4.8
5.3
.4
.8
.6
.35
.1
.5
.2
.4

Scrubber
Slurry
S.G.
1.09
1.09
1.093
1.075
1.082
1.089
1.090
1.090
1.075
1.109
1.085
1.077
1.115
1.085
1.077
1.105
1.074
1.070
1.07
1.10
1.082
1.078

Lime
Sludge
S.G.
1.31
1.3
1.276
1.085
1.262
1.32
1.21
1.25
1.28

1.31
1.047
1.26
1.26
1.29
1.015
1.204
1.336
1.12
1.064
1.05
1.070

Scrubber SO-
Concentration PPM
Inlet Outlet
315
327
378
345
450
384
400
386
450
423
333
400
346
347
459
435
431
440
606
555
541
556

73
115
57
63
66
84
91
77
67
70
51
83
156
143
169
161
145
196
222
208
169
182


-------
Identification No
                                                                              RESEARCH-COTTRELL, INC.






                                                                                    Coal Analysis Report
                                                                                                                                                          HCL.IO  3387	

RCL No
1
•f
3
4
5
6

Tech Dept
No
10291410 C
lo.iisnnn r




Sample Date
10/29/78
10/31/78




Sample Identification and Description
Coal Mine Name and Location
2:10 P.M.
8:00 P.M.




Source/Type Sample
Coal
Coal





Unit






Station







RCL No
1
2
3
4
5
6
Pi
%
Moiature
6.16
8.27




% Ash
11.0
9.81






% Sullur
2 . 66
1.95




(Aa Rec'd Baste)
% «ol Mat






%
Fi>od






Btu






UHtmile Analy$li (At Rec'd Baai>)
*C
63.62
63.33




%H
4. 56
4. 36




%N
1. 25
1. 20




ss
2.66
1 . 95




*O,
JQ.75
11.08




*CL-




















Sulhir Focnu
(At Rec'd Bads)
%
Pyritic






%
Sullale






% Organic
.(by-Di Dry Aid ( % )
StO,





«
Al, 0,






TiO,






Fe,O,






CaO






MflO






Na, O






K, O






So, -






P, O,






Other












'
Undeter.






Tout






Comments or Special Analysts







HC 1074

-------
       APPENDIX  D




Water Plant Survey Data
           65

-------
        Identification No
                           CES  355
                                                                                                RESEARCH-COTTRELL, INC




                                                                                                   Fly Ath Particle Sl» Rtport
                                                                                                                                                                                                 3387

MCL No
1"
20
21
77
37
38

Tech Depl No
pg o. 3 \nij
RS 93102 A
RS 93102 B
B Q a 1 1 o 4



Sample Date






Simple Identlllcatlon and DMcrlpUon
Coal Mine - Name and Location






Utility - Station. Unit







Source/Type





	
Dale/Initials






Ti
                                                         Density Analysis
                                                                                                                       Slew Analysis

RCL No
IE
2C
21
22
37
3fc
Specific
Gr.vily
gms/cc
2. 34
2.45
2.26
2. 50
2.33
2.55
Bulk Density
Compact (Ibs/lt1)






Uncomp (Ibs/lt')






% Finer Than
44 um






74 jjm






149um






297 urn






» 297 um






Comments







                                                                                                    Sub-Sine (Banco) Analysis

RCL No.
1 ft
20
21
22
37
3 9
Percent By Weight Lew Than Indicated Particle Diameter
um
] 1
1.4
1.4
1.4
J-4
1.4
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3.39
2. 89
11.80
9.64
28. 19
2.76
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2.3
2.2
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16.87
13.51
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4.5
4.4
4.5
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26.32
36.57
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                                TECHNICAL REPORT DATA
                         (Please read Inaructions on the reverse before completing)
 1. REPORT NO.
  EPA-600/7-79-247
                                                      3. RECIPIENT'S ACCESSION NO.
4. TITLE ANDSUBTITLE
 EPA Evaluation of Water Plant Lime Sludge in an
  Industrial Boiler FGD System at Rickenbacker AFB
              5. REPORT DATE
              November 1979
              6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
 Robert J. Ferb
                                                      8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
 Cottrell Environmental Sciences
 P.O.  Box 1500
 Somerville, New Jersey 08876
                                                      10. PROGRAM ELEMENT NO.
              EHE624
              11. CONTRACT/GRANT NO.

              Interagency Agreement
12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 Industrial Environmental Research Laboratory
 Research Triangle Park, NC  27711
              13. TYPE OF REPORT AND PERIOD COVERED
              Final; 9/78 - 2/79	
              14. SPONSORING AGENCY CODE
               EPA/600/13
is. SUPPLEMENTARY NOTES IERL-RTP project officer is John E. Williams, Mail Drop 61,
 919/541-2483.
 s. ABSTRACT Tne repor|- gives results of a September 1978-February 1979 test program
 to evaluate lime water softening waste sludge as an alternate reagent for a flue gas
 desulfurization (FGD) system on an industrial boiler at Rickenbacker Air Force
 Base, Ohio. The study also included assessing the availability of the material,
 designing a system to handle and feed the material, and comparing the economics
 with conventional lime and limestone reagents.  The tests showed that such material
 worked very well as a reagent and was comparable to lime performance during ear-
 lier tests. At SO2 removal efficiencies of up to 80%, utilization  exceeded 95%. The
 study showed that as much as 4-5 million tons/year of the material may be available
 much of it in the Midwest U.S. where large deposits of high sulfur coal and a heavy
 population of industrial plants are located. Estimates indicated that use of water
 softening sludge in a typical industrial FGD system results in substantially lower
 annual operating costs compared with either lime or limestone.
 7.
                             KEY WORDS AND DOCUMENT ANALYSIS
                DESCRIPTORS
                                          b. IDENTIFIERS/OPEN ENDED TERMS
                          c. COSATI Field/Group
 Pollution
 Flue Gases
 Desulfurization
 Calcium Oxides
 Sludge
 Water Softening
  Pollution Control
  Stationary Sources
13B
2 IB
07A,07D
07B
 3. DISTRIBUTION STATEMENT
 Release to Public
  19. SECURITY CLASS (ThisReport)
  Unclassified
21. NO. OF PAGES
    78
  20. SECURITY CLASS (This page)
  Unclassified
                          22. PRICE
EPA Form 2220-1 (9-73)
78

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