&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
-------
RESEARCH REPORTING SERIES
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tems. The goal of the Program is to assure the rapid development of domestic
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This document is available to the public through the National Technical Informa-
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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.
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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.
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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
-------
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
-------
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
-------
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.
-------
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
-------
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
-------
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
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-------
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
%
3.39
2. 89
11.80
9.64
28. 19
2.76
>jm
i-3
2.2
2.3
2.2
_2_. 3
2.2
%
B.l-i
7.30
16.87
13.51
•51 .I"!
10.42
um
4.5
4.4
4.5
4.4
«_•;
4.4
%
20.77
26.32
36.57
27.79
sa sn
44.02
um
8 .4
8.3
8.6
8.2
n.1;
8,1
%
31.37
61.43
5S.S7
54.68
KH *fi
78,33
um
?. ; . 4
13.1
n.6
13,0
1, 3. 4
12.9
%
41.04
91.61
7fi. Sfi
79.71
fiR 13
92.40
Aim
23.4
22.9
21. R
22.6
73 . 1
22.4
%
51.15
98.68
Bfi.in
94,11
70.22
94.22
ym
31.0
30.3
11 5
30.0
31.1
29.7
%
54.82
99.42
88.50
97.01
71.34
94.46
>jjm
31.0
30.3
31.5
30.0
31.1
29.7
%
45.18
0.58
11.50
2.99
19.17
0.32
Slatlattcal Data
Mass Median X
Std Dev
RC 1073
-------
KMniilieaiionNo . ... ._CES_-J55_
RESEARCH-COTTRELL. INC.
Fly Aah Partlct* MM ftapoit
RCL No. 3187.
RCL No
12
13
14
15
16
17
Tech. D»pl No.
RS 93110
RS 93116
RAFB 1
RAPR 2
RS 93106
RS 93107
Sample Data
Coal Mine - Nam* and Locmion
Utility - Station. Unit
Source/Type
Date/Intuit
RCL No
12
13
14
15
16
17
iraiMiqr mamfmm awjjm
n .5
30.5
32.4
13.8
31.4
30.2
%
i 7n
7.69
2.42
14.73
23.09
1.15
intlillcal Data
Mau Median 7
Sid. Dev
HC 1073
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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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