& EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-453/R-94-045a
July 1994
Air
Medical Waste Incinerators -
Background Information for
Proposed Standards and Guidelines:
Model Plant Description
and Cost Report
for New and Existing Facilities
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EPA-453/R-94-045a
Medical Waste Incinerators-Background Information for Proposed
Standards and Guidelines: Model Plant Description and Cost Report for
New and Existing Facilities
July 1994
U. S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina
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DISCLAIMER
This report is issued by the Emission Standards Division, Office
of Air Quality Planning and Standards, U. S. Environmental
Protection Agency. It presents technical data of interest to a
limited number of readers. Mention of trade names and commercial
products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available free
of charge to Federal employees, current contractors and grantees,
and nonprofit organizations--as supplies permit--from the Library
Services Office (MD-35), U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711 ([919] 541-2777) or,
for a nominal fee, from the National Technical Information
Service, 5285 Port Royal Road, Springfield, Virginia 22161
( [703]487-4650> .
ill
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IV
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TABLE OF CONTENTS
1.0 INTRODUCTION
2.0 MODEL COMBUSTORS AND CONTROL TECHNOLOGIES FOR
NEW FACILITIES
2.1 MODEL COMBUSTORS
2.1.1 Combustor Designs
2 1.2 Design Waste Charging Capacity . . . .
2.1.3 Actual vs. Design Waste Charging
'Capacity
2.1.4 Design and Operating Parameters . . . .
2.2 CONTROL TECHNOLOGIES •
2.2.1 Combustion Control •
2.2.2 Add-On Control Equipment
3.0 COMBUSTOR AND CONTROL TECHNOLOGY COSTS FOR
NEW FACILITIES
3.1 COMBUSTOR CAPITAL COSTS
3.1.1 Continuous Combustors
3.1.2 Intermittent Combustors
3.1.3 Batch Combustors
3 1.4 Pathological Combustors
3.2 CONTROL TECHNOLOGY CAPITAL COSTS
3.2.1 Combustion Control Costs
3.2.2 APCD Control Costs
3.3 COMBUSTOR ANNUAL COSTS
3.3.1 Electricity
3.3.2 Auxiliary Fuel
3.3.3 Water
3.3.4 Operating Labor
3.3.5 Supervisory Labor
3.3.6 Maintenance Labor
3.3.7 Maintenance Materials
3.3.8 Ash Disposal
3.3.9 Refractory Replacement
3.3.10 Overhead . . . -.
3.3.11 Property Tax, Insurance, and
Administration
3.3.12 Capital Recovery
3.4 CONTROL TECHNOLOGY ANNUAL COSTS
3.4.1 Combustion Control Annual Costs . . .
3.4.2 Wet Control Device Annual Costs . . .
3.4.3 Annual Costs for Control Devices with
an FF •
2
2
3
5
9
10
14
21
22
27
28
29
32
32
32
35
35
37
53
53
55
58
58
59
59
59
59
59
64'
64
64
64
65
65
80
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TABLE OF CONTENTS (continued)
Page
3.5 ACTIVATED CARBON INJECTION COSTS ....... 94
3.5.1 Total Capital Investment for Activated
. Carbon Injection Equipment 94
3.5.2 Annual Costs for Activated Carbon
Injection 97
3.6 SUMMARY OF COMBUSTOR AND CONTROL
TECHNOLOGY COSTS 102
4.0 MODEL COMBUSTORS AND CONTROL TECHNOLOGIES FOR
EXISTING FACILITIES 102
4.1 MODEL COMBUSTORS .......... 102
4.2 MODEL CONTROL TECHNOLOGIES . '. 105
4.2.1 Combustion Controls 105
4.2.2 APCD Control Technologies 106
5.0 COSTS FOR EXISTING FACILITIES 106
5.1 COMBUSTOR CAPITAL AND ANNUAL COSTS .... 106
5.2 CONTROL TECHNOLOGY CAPITAL COSTS 107
5.2.1 Combustion Control Total Capital
Investment 107
5.2.2 APCD Total Capital Investment . . . ! '. 113
5.3 CONTROL TECHNOLOGY ANNUAL COSTS 113
5.3.1 Combustion Control Annual Costs .... 113
5.3.2 APCD Annual Costs 113
6.0 DISTRIBUTION OF MWI POPULATION 113
7,0 CONTINUOUS EMISSION MONITOR COSTS ng
7.1 CONTINUOUS EMISSION MONITORS ! ! ! * 116
7.2 PORTABLE CO MONITORS . ' 12Q
7.3 PROCESS MONITORS _^
7.4 MAINTENANCE SERVICE '.'.'.'. 123
8.0 PERFORMANCE TESTING COSTS !23
9.0 REFERENCES .' 124
VI
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LIST OF FIGURES
Figure 1.
Figure 2 .
Figure 3 .
Figure 4 .
Figure 5 .
Figure 6 .
Figure 7.
Figure 8 .
Figure 9 .
Figure 10 .
Figure 11.
Figure 12 .
Figure 13 .
Figure 14.
Figure 15.
Figure 16.
Purchased equipment costs for continuous
corabustors
Purchased equipment costs for intermittent
combustors
Purchased equipment costs for batch
combustors
Purchased equipment costs for pathological
combustors . . .
Incremental purchased equipment cost for
secondary chamber with 2 -second residence
time
Total capital investment for VS/PB control
device
Total capital investment for VS control
device
Total capital investment for PB control
device
Total capital investment for DI/FF control
device
Total capital investment for' FF control
device
Total capital investment for FF/PB control
device
Total capital investment for SD/FF control
device
Connected horsepower requirements for
intermittent and continuous combustors . . .
Connected horsepower requirements for batch
combustors ; •
Primary chamber volume for intermittent
combustors
Primary chamber volume for continuous
Page
31
33
34
36
38
41
42
43
44
45
46
47
55
C£
fiT
62
vii
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LIST OF FIGURES (continued)
Page
Figure 17. Primary chamber volume for batch combustors . 63
Figure 18. Fan motor size for VS/PB control device ... 74
Figure 19. Pump horsepower for VS/PB control device . . 75
Figure 20. Makeup water flow rate for VS/PB control
device 76
Figure 21. Slowdown rates for VS/PB control device ... 79
Figure 22. Fan motor size for DI/FF control device ... 84
Figure 23. Gas flow rate in DI/FF control device .... 86
Vlll
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LIST OF TABLES
TABLE 1.
TABLE 2.
TABLE 3 .
TABLE 4.
TABLE 5.
TABLE 6 .
TABLE 7.
TABLE 8.
TABLE 9.
TABLE 10.
TABLE 11.
TABLE 12.
TABLE 13 .
TABLE 14.
TABLE 15.
TABLE 16.
TABLE 17.
TABLE 18.
TABLE 19.
TABLE 20.
TABLE 21.
SUMMARY OF MODEL COMBUSTORS
SUMMARY OF EXISTING CONTINUOUS COMBUSTORS . .
SUMMARY OF EXISTING INTERMITTENT COMBUSTORS .
SUMMARY OF EXISTING BATCH COMBUSTORS ....
SUMMARY OF EXISTING PATHOLOGICAL COMBUSTORS .
CONTINUOUS AND INTERMITTENT MODEL COMBUSTORS
BATCH MODEL COMBUSTOR
PATHOLOGICAL MODEL COMBUSTOR
CONTROL DEVICE OPERATING PARAMETERS
EQUATIONS TO ESTIMATE PURCHASED EQUIPMENT
COSTS FOR MODEL COMBUSTORS
SUMMARY OF MODEL COMBUSTOR CAPITAL COSTS . .
COMBUSTION CONTROL COSTS FOR MODEL
COMBUSTORS
EQUATIONS TO ESTIMATE TOTAL CAPITAL
INVESTMENT FOR APCD'S
ANNUAL COSTS FOR NEW COMBUSTORS
COMBUSTION CONTROL ANNUAL COSTS FOR NEW MWI'S
EQUATIONS TO ESTIMATE ANNUAL COSTS FOR VS/PB
CONTROL DEVICES
EQUATIONS TO ESTIMATE ANNUAL COSTS FOR VS
CONTROL DEVICES
EQUATIONS TO ESTIMATE ANNUAL COSTS FOR PB
CONTROL DEVICES
VS/PB ANNUAL COSTS FOR EACH MODEL COMBUSTOR .
VS ANNUAL COSTS FOR EACH MODEL COMBUSTOR
PB ANNUAL COSTS FOR EACH MODEL COMBUSTOR . .
Page
3
6
8
9
10
11
12
13
23
30
30
37
48
54
66
68
w w
69
v y
70
/ W
71
72
73
IX
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LIST OF TABLES (continued)
Page
TABLE 22. EQUATIONS USED TO ESTIMATE ANNUAL COSTS FOR
DI/FF CONTROL DEVICES 82
TABLE 23. DI/FF ANNUAL COSTS' FOR EACH MODEL COMBUSTOR . 83
TABLE 24. EQUATIONS TO ESTIMATE ANNUAL COSTS FOR
FF CONTROL DEVICES 90
TABLE 25. FF ANNUAL COSTS FOR EACH MODEL COMBUSTOR . 91
TABLE 26. EQUATIONS TO ESTIMATE ANNUAL COSTS FOR FF/PB
CONTROL DEVICES . . ' 92
TABLE 27. FF/PB ANNUAL COSTS FOR EACH MODEL COMBUSTOR . 93
TABLE 28. EQUATIONS USED TO ESTIMATE ANNUAL COSTS FOR
SD/FF CONTROL DEVICES 95
TABLE 29. SD/FF ANNUAL COSTS FOR EACH MODEL
COMBUSTOR 96
TABLE 30. EQUATIONS TO ESTIMATE CAPITAL AND ANNUAL
COSTS FOR ACTIVATED CARBON INJECTION .... .98
TABLE 31. CAPITAL AND ANNUAL COSTS FOR ACTIVATED
CARBON INJECTION FOR DI/FF AND FF/PB CONTROL
DEVICES 99
TABLE 32. CAPITAL AND ANNUAL COSTS FOR ACTIVATED
CARBON INJECTION FOR SD/FF CONTROL DEVICES . 100
TABLE 33. SUMMARY OF COMBUSTOR AND CONTROL TECHNOLOGY
CAPITAL COSTS 103
TABLE 34. SUMMARY OF COMBUSTOR AND CONTROL TECHNOLOGY
TOTAL ANNUAL COSTS 104
TABLE 35. CAPITAL AND ANNUAL COSTS FOR EXISTING
COMBUSTORS 108
TABLE 36. TOTAL CAPITAL INVESTMENT FOR 2-SECOND
SECONDARY CHAMBER COMBUSTION CONTROL
RETROFITS 109
TABLE 37. DOWNTIME COSTS ASSOCIATED WITH COMBUSTION
CONTROL DEVICES ^ 110
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LIST OF TABLES (continued)
/
TABLE 38 TOTAL CAPITAL INVESTMENT FOR 1-SECOND
SECONDARY CHAMBER COMBUSTION CONTROL
RETROFITS •
TABLE 39 TOTAL ANNUAL 1-SECOND SECONDARY CHAMBER
COMBUSTION CONTROL RETROFIT COSTS
TABLE 40 TOTAL ANNUAL 2-SECOND SECONDARY CHAMBER
COMBUSTION CONTROL RETROFIT COSTS ......
TABLE 41. DISTRIBUTION OF NEW UNITS
TABLE 42. DISTRIBUTION OF EXISTING UNITS IN FIVE MAJOR
INDUSTRIES
TABLE 43 DISTRIBUTION OF EXISTING MWI'S IN
MISCELLANEOUS/UNIDENTIFIED INDUSTRIES . . .
TABLE 44. CONTINUOUS EMISSION MONITOR COSTS FOR NEW
MWI'S
TABLE 45. COMPARISON OF VENDOR AND EMTIC CEM CAPITAL
COSTS
Page
112
114
115
. 117
118
119
119
121
XI
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MODEL PLANT DESCRIPTION AND COST REPORT
1.0 INTRODUCTION
This report is one of a series of reports prepared to
support the development of new source performance standards
(NSPS) and emission guidelines for medical waste incinerators
(MWI's) under Section 129 of the Clean Air Act. The other
reports in the series provide background information on the
medical waste incineration industry, the process description, the
emission control technologies, and the environmental impacts
associated with selected control technologies.
This report presents the design and operating parameters and
costs for model plants that represent the MWI source category.
These model plants will be used in the analysis of cost,
economic, and environmental impacts for development of NSPS and
emission guidelines. The source category consists of several
industries, including (but not limited to): (1) hospitals,
(2) commercial waste disposal facilities,
(3) laboratories/research facilities, (4) veterinaries, and
(5) nursing homes.
Model plants consist of model combustors in combination with
air pollution control technologies. A total of 77 model plants
were developed to represent new MWI's, and 84 model plants were ,
developed to represent existing MWI's. The new model plants are
based on the combination of 7 model combustors with 11 emission
control technologies. The existing model plants are based on
7 model combustors and 12 emission control technologies.
The remainder of this report is divided into eight sections.
Section 2.0 presents the design and operating parameters for the
7 model combustors and 11 control technologies that were
developed to represent new MWI's. The model combustors
characterize combustor designs, waste types, waste charging
capacities, operating temperatures, operating hours, and gas
residence time in the secondary chamber. The control
technologies consist of combustion controls alone or in
combination with add-on air pollution control devices (APCD's).
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The specified parameters for each model combustor and control
technology are based on typical or predominant valves for MWI's
installed in the last 5 years. Section 3.0 presents the capital
and annual costs for these model combustors and control
technologies. All costs are presented in October 1989 dollars.
Section 4.0 presents the design and operating parameters for
the 7 model combustors and 12 control technologies that represent
existing MWI's. The model combustors are identical to those
developed to represent new MWI's, except that the gas residence
time in the secondary chamber is lower for most existing models.
(This is the only parameter that is significantly different for
all existing MWI's than for those installed in the last 5 years.)
The control technologies are also identical for both new and
existing models, but one additional combustion control technology
has been evaluated for existing models. Section 5.0 presents the
costs to retrofit existing model combustors with these control
technologies.
Section 6.0 presents the distribution of both new and
existing model combustors among the various industries. Section
7.0 presents the capital and annual costs for emission and
process monitors. Section 8.0 presents estimated performance test
costs, and Section 9.0 presents the references. Appendices A
through D present algorithms for estimating total annual costs
for the model combustors and three representative control
technologies.
2.0 MODEL COMBUSTORS AND CONTROL TECHNOLOGIES FOR NEW FACILITIES
This section presents the design and operating parameters
for the 7 model combustors and 11 control technologies developed
to represent new MWI installations. Model combustor parameters
are presented in Section 2.1. Control technology parameters are
described in Section 2.2.
2.1 MODEL COMBUSTORS
A total of seven model combustors have been developed to
represent the population of new MWI's. Table 1 summarizes the
industries that typically use MWI's represented by each model.
As shown in Table l, most of the model combustors are generic in
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that they may represent MWI's in more than one industry.
Knowledge about the types of combustors in some industries is not
as complete as for other industries, but the models span the
range of design capacities and options offered by MWI
manufacturers. Therefore, a new MWI in any industry will be
adequately represented by at least one of the seven models.
SUMMARY OF MODEL
Combustor type
_.
Intermittent
•«^«^—«^—^•—^•™—~™—~™™~
Continuous
Batch
200 Ib/hr
600 Ib/hr
1,500 Ib/hr
1,000 Ib/hr
1,500 Ib/hr
500 Ib/batch
Hm
cb
;;SS^^^^^^^^=:^^-——""^ ,
*Codes represent hospitals, nursing homes, laboratories, and
veterinaries. , . .
bCode represents commercial facilities.
Most of the parameters considered in selecting the model
combustors were determined from analysis of the existing MWI
population. Information was provided by incinerator
manufacturers, hospitals, and commercial facilities in response
to U. S. Environmental Protection Agency (EPA) requests for
information. Additional information was obtained from surveys of
MWI's conducted by four States. Characteristics for new units
are assumed to be similar to characteristics of those units ,
recently installed to meet more stringent requirements for
combustion temperatures and residence times.
2.1.1 Combustor Designs
The seven model combustors are based on four designs. Three
of these designs (continuous, intermittent, and batch units) are
used to burn mixed red bag and general waste. The fourth design
is used to burn pathological waste (i.e., tissues, organs, body
parts, blood, and body fluids removed during surgery, autopsy.
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and biopsy). The primary chambers in continuous, intermittent,
and batch MWI's operate under substoichiometric air conditions,
while pathological MWI's operate under excess-air conditions.
Other distinguishing features of each design are described below.
2.1.1.1 Continuous. A continuous MWI is one that can
accommodate waste charging for an unrestricted length of time
because ash is automatically discharged from the incinerator on a
periodic or continuous basis. The initial step in the operating
cycle is to preheat the secondary chamber to operating
temperature. Concurrently, the primary chamber is preheated, but
it may not be preheated to the operating temperature. The air
blowers are then turned on, and the unit is ready to receive
waste. An automatic ram is used to charge relatively small
quantities of waste at frequent, regulated time intervals--
typically every 6 to 15 minutes. As the waste burns down to ash
it travels through the primary chamber by one of several methods.
In most continuous units, one or more internal transfer rams push
the waste across a fixed hearth or a series of stepped hearths.
The lowest ram pushes ash off the hearth at the discharge end of
the chamber. A few continuous units are designed with a primary
chamber that is an inclined rotary kiln. As the chamber rotates,
the solids tumble within the chamber and slowly move down the
incline toward the discharge end of the kiln.
2«1-1.2 Intermittent. An intermittent combustor, depending
on its size, is designed to accept waste charges at periodic
intervals for between 8 and 14 hours. Once ash builds up to an
unacceptable level, the unit must be shut down and cooled so that
ash can be removed. The operating procedure before charging is
identical to that for continuous combustors. Intermittent
combustors are designed to have waste charged either manually or
with an automatic ram on a periodic basis--typically every 6 to
15 minutes. However, some intermittent MWI's are actually
charged at uneven intervals, whenever waste is available. After
the last load, the remaining waste in the primary chamber burns
down to ash (with auxiliary fuel, as necessary) over 2 to
6 hours. The combustor is then allowed to cool before ash is
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either manually removed or discharged by an operator-activated
ash ram. If the combustor operates for only a few hours, ash
need not be removed at the end of each operating cycle.
2.1.1.3 Batch. A batch combustor is one that is designed
to burn only one load of waste at a time. A single "batch" of
waste is first charged (either manually or with a ram feeder) to
a cold incinerator. Subsequent sequential steps in the operating
cycle are to preheat the secondary chamber, ignite the primary
chamber burner(s), burn the waste down to ash, allow the unit to
cool, and manually remove the ash. Except for small batch MWI's,
this is a 2-day procedure. If the incinerator is not fully
loaded, ash need not be removed during each operating cycle.
2.1.1.4 Pathological. In comparison with the other
combustor designs, pathological combustors are most similar to
intermittent units. However, as noted above, pathological
combustors are used to burn a different type of waste, and they
are designed with higher combustion airflow rates in the primary
chamber. Pathological combustors also have larger primary
chamber burners than intermittent units that burn an equivalent
amount of mixed medical waste. In addition, the burners in
pathological combustors operate for a greater percentage of time
to evaporate the high moisture levels in pathological waste. The
waste charging and ash removal procedures for pathological MWI's
are the same as those for intermittent MWI's.
Incinerator manufacturers also make batch pathological
combustors. However, the only known use of such combustors is at
crematories, which, if they are only burning human remains, are
not considered to be MWI's. Therefore, batch pathological
combustors are not considered in this analysis.
2.1.2 pesicrn Waste Charging Capacity
The range of design waste charging capacities (design
capacities) for existing MWI's represented by each of the four
combustor types was divided into segments, and appropriate model
capacities were chosen to represent each segment. This process
resulted in a total of seven model combustors. Most of the
specified model design capacities are approximately equal to the
5
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arithmetic mean of capacities in the range segment. The design
capacity of an MWI depends on the heat release rate for which the
unit was designed and the heating value of the waste. Typically,
MWI manufacturers specify the design capacities for their units
based on heating values of 8,500 British thermal units per pound
(Btu/lb) for combinations of general/red bag waste and
1,000 Btu/lb for pathological waste.1'2 The rationale for the
specified design capacities for each model combustor is presented
in the four subsections below.
2'1-2-1 Continuous Models. The continuous model combustors
were developed with design capacities of 1,000 and 1,500 pounds
per hour (Ib/hr). Table 2 summarizes available information about
existing continuous MWI's. This information indicates that
almost all of these units are used by commercial facilities and
hospitals.
SUMMARY OF EXISTING CONTINUOUS COMBUSTORSa
Industry segment/capacity
Hospitals
350-900
901-1,100
1,101-1,910
Total
Commercial
500-1,000
1,001-2,000
2,001-6,588
Laboratories/research
875-1,500
No. of units
28
14
62
5
31
3
4
Avera
in re
Ib/hr
713
1,566
4,696
information was obtained from five incinerator
*
Design capacities for existing continuous units at hospitals
range from about 350 to 1,850 Ib/hr. The 1,000 Ib/hr model was
selected to represent all continuous units at hospitals because
it approximates the average size of all known continuous units at
hospitals, and it is the most common size.2'7'10
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Design capacities for existing or planned continuous units
at commercial facilities range from 500 to 6,250 Ib/hr. One
model, with a design capacity of 1,500 Ib/hr, was developed to
represent these units. This model was developed because 20 of
the 39 known commercial units are this size, and it is only
slightly smaller than the average capacity of the 31 units with
capacities in the range of 1,000 to 2,000 Ib/hr.2,7-10
2.1.2.2 Tnt-.ermittent Models. Three intermittent model.
combustors were developed with design capacities of 200, 600 and
1,500 Ib/hr. The 200 Ib/hr model represents combustors with
design capacities of 50 to 400 Ib/hr; the 600 Ib/hr model
represents combustors in the range of 401 to 1,000 Ib/hr; and the
1,500 Ib/hr model represents combustors larger than 1,000 Ib/hr.
Table 3 summarizes the information from incinerator
manufacturers, hospitals, and State surveys that was used to
determine range segments and design capacities. Some of these
surveys show capacities for existing intermittent MWI's range
from less than 50 Ib/hr to 2,200 Ib/hr. However, the smallest
known MWI currently produced is 50 Ib/hr.11 This information
also indicates that the design capacities of over two-thirds of
existing the intermittent MWI's are less than or equal to
400 Ib/hr. About 25 percent have design capacities between
401 Ib/hr and 1,000 Ib/hr. Only 6 percent of existing combustors
are larger than 1,000 Ib/hr. According to available information,
this combustor type is used in all industry segments except
commercial facilities.2-4'7'8'12"14
2.1.2.3 Ratch Models. One batch model was developed with a
design capacity of 500 pounds per batch (Ib/batch). This size is
equal to the design capacity of a combustor that is produced by
the only known manufacturer of batch MWI's. It was selected
because it is between the average size of all batch MWI's and the
most common size. Sales information from the manufacturer of
batch MWI's is summarized in Table 4. This information shows
batch MWI's range in size from 150 to 3,800 Ib/batch, and nearly
Q
all of them are installed at hospitals.
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TABLE 3 . SUMMARY OF EXISTING INTERMITTENT COMBUSTORSa
Industry segment/capacity range,
Ib/hr
Hospitals
50-400
401-1,000
>1,000
Laboratories and research
facilities
50-400
401-1,000
>1,000
Nursing homes
50-400
401-1,000
Veterinaries
50-400
401-1,000
>1,000
No. of units
513
212
50
46
21
6
37
2
10
0
0
Average
capacity in
range, Ib/hr
199
597
1,484
218
743
2,165
115
538
115
The tabulated information is from three incinerator manu-
facturers, three State surveys, hospitals that responded to
EPA information requests, and emissions test
reports.^"*' '»8,12-14 inforrnation from incinerator
manufacturers has been limited to installations since 1980
because there is a trend toward larger sizes in recent
years. Due to limitations in the data, several assumptions
were_made. Most incinerator manufacturers did not
distinguish between pathological and mixed waste combustors.
Because mixed waste combustors are more common, it was
assumed that all of the incinerators that they reported are
mixed waste units. Because the definitions of incinerator
types used in this analysis are different than those used by
the States, it was assumed that any incinerator permitted to
burn waste other than Type 4 waste was an intermittent unit.
No reported capacities below 50 Ib/hr in the State surveys
were included in the analysis because no evidence indicates
that such small combustors are currently being produced.
Veterinaries were distinguished from animal shelters on the
basis of the facility name, but several facilities may be
misrepresented because a clear distinction was rarely
apparent. Finally, a few facilities may have been described
by more than one respondent.
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TABLE 4. SUMMARY OF EXISTING BATCH COMBUSTORS
Industry segment/capacity
range, Ib/batch
Hospitals
150
340-970
1,620-3,800
No. of units
22
77
16
Average capacity
in range,
Ib/batch
150
605
2,070
aThe tabulated information was obtained from one incinerator
manufacturer.
2.1.2.4 Pathological Model. One pathological model was
developed with a design capacity of 200 Ib/hr. The specified
capacity is based primarily on information from the New York, New
Jersey, and Washington State MWI surveys, which is summarized in
Table 5. This information shows that the capacities of existing
incinerators that burn pathological waste (i.e., MWI's that are
permitted to burn only Type 4 waste) have design capacities
ranging from 50 to 2,000 Ib/hr. The majority of these
pathological incinerators are small; more than 90 percent of the
units have capacities less than or equal to 300 Ib/hr.
Similar data were provided by hospitals in responses to EPA
information requests; all of the pathological incinerators at
these hospitals have capacities less than 300 Ib/hr.
2.1.3 Actual vg- Design Waste Charging Capacity
The actual waste charging capacity (actual capacity) is
distinguished from the design capacity based on differences
between the actual waste heating values and those typically used
by manufacturers when expressing incinerator design capacities.
As noted above, incinerator manufacturers typically use
8,500 Btu/lb as the heating value for general/red bag waste.
Although measured waste heating values are not available,
charging rates measured during emissions tests and other
information show the average hourly general waste charging rates
for intermittent and continuous units over an operating cycle are
about two-thirds (67 percent) of the design rates specified by
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TABLE 5. SUMMARY OF EXISTING PATHOLOGICAL COMBUSTORS
Range, Ib/hr
No. of units in each range
50-100
101-300
>300
Average capacity in each range,
Ib/hr
50-100
101-300
300
Industry segment
Hospitals
Laboratories/research
Nursing homes
Veterinaries
91
21
11
68
58
22
3
13
9
7
0
5
80
68
56
66
184
194
198
173
622
569
—
894
aThe tabulated information was obtained from three State MWI surveys and from hospital responses to
EPA information requests.^.12-14 ^he State surveys identified the types of waste that each facility is
permitted to burn. It was assumed that any facility permitted to burn only Type 4 waste has a
pathological incinerator.
manufacturers.15"20 Charging rates during the first few hours of
an operating cycle may be at the design rate, but this rate
cannot be sustained. Also, the actual charges to one batch unit
during emissions tests were slightly higher than 67 percent of
the design charge size.21 Since the incinerators are designed
for a specific, constant heat release rate, these average actual
charging rates indicate the actual general waste heating value is
about 12,750 Btu/lb. This value was used to develop the actual
capacities for the continuous, intermittent, and batch models in
Tables 6 and 7.
The actual capacity for the pathological model is the same
as the design capacity, because the actual heating value of
pathological waste is believed to be about 1,000 Btu/lb (as
reported 'by manufacturers) .
2.1.4 Design and Operating Parameters
The seven model combustor designs are further characterized
by design and operating parameters. Each of the parameters is
discussed in the subsections below, and Tables 6 through 8
present the parameter specifications for each model combustor.
Recovery of heat from the stack gases was not specified for any
of the models because the procedure is used with very few
existing MWI's.
10
-------
TABLE 6. CONTINUOUS AND INTERMITTENT MODEL COMBUSTORS
Parameter\model combustor
Design thermal release rale, MMBtu/hr
Design capacity. Ib/hr
(based on 8.500 Btu/lb)
Actual capacity, Ib/hr
67 % of design
No. 1
13
1,500
1,000
No. 2
9
1,000
667
Intermittent models
No. 3
12.8
1,500
1,000
— frpneral and/o
No. 4
5.1
600
400
r red bae
1
No. 5
1.7
200
133
...................
'Type of waste (general/red bag)
[Design operating hours, hr/d
Charging (maximum)
Burndown
Design d/yr (maximum)
Actual operating hours
Preheat (a)
Charging, hr/d
Burndown (a)
Cooldown (b)
Actual d/yr
Combustion air
Overall, percent theoretical
H Primary chamber, percent theoretical
llMinimum operating temperature
II Primary chamber, F
S^nd.iry chamber. F
HGas residence time in secondary chamber, s
1 Auxiliary fuel type
Ancillary fuel consumption, ft3/hr
11 Flue gas parameters
I Temperature, F (out of secondary chamber)
| Oxygen concentration, percent (dry)
1 Volumetric flow rates
II dscfm
|| wscfm (assume 10 percent moisture)
B aefm (out of secondary chamber)
HStack parameters
Volumetric flow rate, acfm
Stack temperature, F
Suck height, ft
Stack diameter, ft
Automatic ram
M/A
340
n ^
T?«l
7,776
300
50
1,200
1,700
1
NO
2,576
1,700
14
4,747
5,275
21,578
19,580
1,500
2.
*)A
N/A
340
05
9
2
0
324
3,726
300
50
1,200
1,700
1
NG
1,717
1,700
14
3,165
3,516
14,385
13,053
1,500
Af\
14
4
340
0.5
75
4
t
312
4,368
300
50
1,200
1,700
1
NG
2,576
1,700
14
4,747
5,275
21478
19,580
1300
d
2.3 1 2-
14
340
0.5
7.5
4
-i
312
4,368
300
50
1,200
1,700
1
NG
1,030
1,700
14
1,899
2,110
8,631
7,832
1,500
40
10 1
A
340 11
0.5
5.5
4 1
2 '
312
3,744
300
50
1,200
1,700
1
NO
343
1,700
2,877
2,611
1,500
40
,2,
jmwfc m«»"^^^t_^__^^__^^^_^_^___^M,^^^^^^^^^^^^^Bii^^^BH^M^^Mi^^^ai^^Mi»*^"'ll™^"^"l^^a"^^^^^
(a) Preheat and burndown times are given for each operating cycle; for the 1,500 Ib/hr continuous unit, the
operating cycle is two weeks, and for the 1,000 Ib/hr continuous unit and the intermittent
units, the operating cycle is one day.
(b) The cooldown hours represent the average number of hours during which the
combustion airblowers remain on. The average is based on 6 hours for 1/3 of intermittent
units and 0 hours for 2/3 of intermittent units.
11
-------
TABLE 7. BATCH MODEL COMBUSTOR
Pararnetcr\model combustor
No. 6
Thermal release rate, MMBtu/hr
Design capacity, Ib/batch
(based on 8,500 Btu/lb)
Size of primary chamber, f t3
Actual capacity, Ib/batch
67 % of design
Type of waste
Feed system
4.3
500
112
333
General and/or red bag
Manual
Design operating hours, hr/d
"low air" phase hr/d
"high air" phase hr/d
Cooldown phase
Design d/yr (maximum)
Actual operating hours, hr/d
Preheat phase
"low air" phase
"high air" phase
Cooldown
Actual d/yr
Actual hr/yr
7
5
10
340
0.5
7
5
10
160
3,600
Combustion air
Overall, percent theoretical
Primary chamber, percent theoretical
300
50
Minimum operating temperatures
Primary chamber, F
Secondary chamber. F
1,200
1,700
Gas residence time in secondary chamber, s
Auxiliary fuel type
Auxiliary fuel consumption, ft3/hr
1
NG
859
Flue gas parameters
Temperature, F
Oxygen concentration, percent (dry)
Volumetric flow rates
dscfm
wscfm (assume 10 percent moisture)
acfm
1,700
14
455
506
2,068
Stack parameters
Volumetric flow rate, acfm
Stack temperature, F
Suck height, ft
Stack diameter, ft
1,877
1,500
28
1
12
-------
TABLE 8. PATHOLOGICAL MODEL COMBUSTOR
meter\model combustor
(Design thermal release rate, MMBtu/hr
Design capacity, Ib/hr
(based on 1,000 Btu/lb)
Actual capacity, Ib/hr
100 % of design
Type of waste
Feed system .
0.2
200
200
General and/or red bag
Automatic ram
Design operating hours, hr/d
Charging (maximum)
Burndown
Design d/yr (maximum)
Actual operating hours, hr/d
Preheat
Charging
Burndown
Actual d/yr
Actual hr/yr
10
4
340
0.5
5.5
4
"312
3.120
Combustion air
Overall, percent excess
Primary chamber, percent excess
200
80
Minimum operating temperature
Primary chamber, F
Secondary chamber, F
1,200
1,700
llGas residence time in secondary chamber, s
|Auxiliary fuel type
[Auxiliary fuel consumption, ft3/hr
1
NG
1.796
jjFlue gas parameters
Temperature, F
Oxygen concentration, percent (dry)
Volumetric flow rates
dscfm
wscfm (assume 10 percent moisture)
acfm
1,700
14 I
730
811
3,318
(Stack parameters
Volumetric flow rate, acfm
Stack temperature, F
Stack height, ft
Stack diameter, ft
3,011
1,500
20
1.0
13
-------
2.1.4.1 Waste Charging System. Manual charging is
specified for some of the models, and automatic charging systems
are specified for other models. Typically, an automatic system
consists of a charging ram.
Automatic charging is specified for all intermittent models.
Responses to EPA information requests show that about 50 percent
of the MWI's with capacities greater than 400 Ib/hr have
automatic charging equipment, and 33 percent of smaller MWI's
have automatic charging systems.7 However, two incinerator
manufacturers indicated that automatic charging equipment is
installed on nearly all of their new incinerators.3'4 Another
incinerator manufacturer indicated that automatic charging
equipment is standard equipment for the larger models and an
option for the smaller models.2'22
Automatic charging equipment is specified for both
continuous models. This equipment is specified because it is
used by all of the continuous MWI's for which information about
the charging system is available.7'8
Manual charging is specified for the batch model because
both the manufacturer's installation lists and responses to EPA
information requests indicate that this approach is used by all
existing facilities.7'9
The pathological model is specified with manual charging
because most of the small pathological units described in
responses to EPA information requests are charged manually.7
2.1.4.2 Combustion Air. According to several incinerator
manufacturers, 50 percent of the air theoretically required for
combustion is provided in the primary chamber of continuous and
intermittent incinerators. Overall, 200 percent of the
theoretical amount is introduced (i.e., 100 percent excess air if
one considers total air for both the primary and secondary
chambers).3'5'23 However, the specified excess air levels for
continuous, intermittent, and batch models are based on the
actual results from emissions tests. These tests show the
average oxygen concentration in the stack gas is about
14 percent, and the average overall excess-air level is about
14
-------
200 percent (i.e., 300 percent of theoretical).8'15'19'21 The
specified airflow rate to the primary chamber is 50 percent of
the theoretically required amount, as indicated by the
manufacturers .
The overall excess air level for the pathological model also
was assumed to be 200 percent. This value was selected because
the oxygen (02) concentration in the exhaust gas and the overall
excess air level were determined to be 15.7 percent and
270 percent, respectively, for one pathological MWI.19 Both of
these values are within the ranges of values for continuous and
intermittent MWI' fl. The 200 percent value also has been reported
as typical elsewhere.24 Excess-air levels for the primary
chamber are not available from emission tests and were assumed to
be 80 percent.24
2 1.4.3 ftag Resif^nce Tim** in the Secondary Chamber.
Available data are insufficient to characterize the secondary
chamber residence time for the existing MWI population. However,
limited data show that older units typically have residence times
that range from essentially 0 seconds up to about 1 second; most
newer units have residence times of at least 1 second; and some
may be as long as 2 to 3 seconds. A 1-second residence time has
been assumed as baseline for all models representing new MWI's
because it is a conservative estimate for determining cost
impacts .
2.1.4.4 Minimum Primary and flafiondary Chamber Operating
The specified minimum operating temperatures for
.
each model combustor type are 1200°F in the primary chamber and
1700°F in the secondary chamber. These temperatures are based on
data provided by hospitals and commercial facilities in responses
to EPA information requests. The responses indicated that
operating temperatures vary widely, both at individual facilities
and among facilities. Minimum operating temperatures were
reported from 500° to 1950°F for the primary chamber and 1050° to
'2150°F for the secondary chamber.
2.1.4.5 «™™ »* operation. Specified hours of operation
are based on information from hospitals and commercial facilities
15
-------
that responded to EPA information requests, incinerator
manufacturers, and State surveys. This information was used to
develop hours of operation for MWI's at hospitals and commercial
facilities. For each model, the hours of operation include the
time for the preheat, burning (or charging), and burndown phases.
Also included is the time while the combustion air blowers
operate during the cooldown phase of intermittent and batch
MWI's.
According to responses from hospitals and commercial
facilities to EPA information requests, the most common preheat
time for intermittent and batch combustors is about 0.5 hour.7
Preheat times should be similar for other combustors. Therefore,
this time has been specified for all of the models. The
specified 'burning and burndown times, cooldown hours during which
combustion air blowers operate, the total operating hours per
year (hr/yr), and the basis for each are described in the
subsections below.
2.1.4.5.1 Continuous models. Typically, commercial
facilities operate for as much time as possible. Under ideal
circumstances, the incinerators are only shut down an average of
1 day every other week for preventive maintenance and repairs.
Adhering to this schedule would allow the incinerator to operate
more than 8,100 hr/yr. However, according to the responses from
commercial facilities to EPA information requests, commercial
MWI's actually operate an average of about 7,776 hr/yr.20 This
utilization rate was specified for the 1,500 Ib/hr continuous
model. It was assumed that this operating rate can be
characterized as 24 hours per day (hr/d) for 324 days per year
(d/yr) (i.e., 26 2-week operating cycles per year with downtime
of l day for preventive maintenance -in every cycle and 2 or
3 additional days for corrective maintenance every 2 months).
Included in the hours for the first and last days of the
operating cycle are the hours for preheat and burndown,
respectively. For continuous units, the burndown time is
equivalent to the solids retention time. According to
manufacturers, the average burndown time is about 2 hr.2'4»23/25
16
-------
The 1,000 Ib/hr continuous model combustor, which represents
units at hospitals, is specified with 3,726 hr of operation per
year. Responses from three hospitals to EPA information requests
indicated that continuous units at hospitals operate about
11.5 hr/d for 340 d/yr.7 However, based on the information from
numerous commercial facilities, it was assumed that the
1,000 Ib/hr continuous model would operate only 324 d/yr. The
11.5 hr/d includes 0.5 hr/d for preheat, 9 hr/d for burning, and
2 hr/d for burndown.
•2.1.4.5.2 Tntermittgnt models. The specified hours of
operation for the 200 Ib/hr model are 3,744 hr/yr, which can be
characterized as 12 hr/d for 312 d/yr. For the larger models,
the specified hours of operation are 4,368 hr/yr, or 14 hr/d for
312 d/yr.
The operating hours are based on responses from hospitals to
EPA information requests, results of the New York survey, and
information from incinerator manufacturers. The hourly rates
provided in response to the EPA information requests include the
preheat, burning, and burndown phases.7 The hourly rates
reported in the New York survey were assumed to be only for the
burning phase.12 In addition, all reported values less than
400 hr/yr in the New York survey were not included in the
analysis. Most of the facilities that reported less than
400 hr/yr indicated that they operated their incinerator for
1 hr/d. Even if this operating time is correct for existing
incinerators, it is reasonable to assume that new incinerators
would not be operated for such a short amount of time. Based on
information from incinerator manufacturers, the burndown hours
for the New York facilities were estimated to be 4 hr/d. Preheat
for the New York facilities was estimated to be 0.5 hr/d.
For all intermittent models, it was estimated that the
primary chamber combustion air blower remains on for an average
of 2 hours during the cooldown phase. This estimate is based on
A the cooldown operation of intermittent combustors from the three
• major MWI manufacturers. Combustion air blowers in combustors
from two of these manufacturers are designed to shut off at the
17
-------
end of the burndown period. The combustors from the third
manufacturer are designed to maintain the flow of combustion air
for about 6 hours during the cooldown phase. Although the exact
share of the intermittent combustor market held by each of these
three manufacturers is not available, and the operation of the
combustion air blower in combustors from most other manufacturers
is not known, it was assumed that the combustion air blower
remains on for 6 hours during the cooldown phase for one-third of
intermittent combustors, while it is shut off at the end of the
burndown phase in the other two-thirds of intermittent
combustors.
2.1.4.5.3 Batch models. According to the manufacturer of
batch combustors, it takes from 10 to 14 hr, depending on chamber
capacity, to complete the burning and burndown phases of the
operating cycle. Cooldown then takes another 10 hr. After the
secondary chamber has been preheated and waste has been loaded
into the primary chamber, the primary chamber burner is ignited.
The waste then burns for 7 hr in a "low air" phase, in which the
primary chamber is starved for combustion air. The combustor
then enters a "high air" burndown phase, which lasts from 3 to
7 hr, depending on the size of the unit.26 During cooldown, the
burners are turned off, but the combustion air blower remains on
and modulates between high and low flow, depending on the primary
chamber temperature. After 10 hr, the blowers are turned off.
Since the temperature is still 500° to 600°F in the primary
chamber, several additional hours are required before the ash
cleanout door can be opened.21
According to hospitals that responded to EPA information
requests, about 47 percent of batch units are run 6 or 7 days per
week (d/wk), and 33 percent run less than 3 d/wk.7 However,
these responses do not distinguish between the number of days
when the incinerator is in use and the number of times waste is
actually charged. Based on the information from the manufacturer
and observations during an emissions test, the operating cycle of
the 500 Ib/batch model is more than 24 hr. For operator
convenience that means the cycle lasts 2 days, and a weekly
18
-------
schedule consists of three operating cycles followed by one day
off for preventive maintenance and repairs. This schedule
results in 160 operating cycles per year.
As shown in Table 7, the 500 Ib/batch model is specified
with 3,600 hr/yr. These hours include the preheat, "low-air,"
"high-air," and cooldown phases of the operating cycles.
2.1.4.5.4 Pat-.hQloaical models. Data from the responses to
EPA information requests and the results of the New York survey
show operating hours for pathological combustors are less than
80 percent of the value for small intermittent units (i.e., MWI's
that are represented by the 200 Ib/hr intermittent model
combustor burning mixed medical waste). However, the specified
operating hours for the pathological model are the same as those
for the 200 Ib/hr intermittent model because (l) significantly
less data are available on the operation of pathological
combustors, (2) both combustor designs are used in the same
industries, (3) the design hours of operation are the same for
both combustors, and (4) it is likely that the utilization rates
for both combustors need to be about the same to make it
economical to operate them.
2.1.4.6 Pine Gas Parameters. Three of the flue gas
parameters on which the design of add-on air pollution control
equipment is based are temperature, moisture content, and
volumetric flow rate. These parameters are discussed below.
The specified flue gas temperatures are based on the minimum
secondary chamber temperature. As indicated above, responses
from hospitals to EPA information requests indicate that the
minimum secondary chamber temperatures for all combustor types
is, on average, 1700°F. The average flue gas moisture content,
based on data from the emission test reports, is about
10 percent.8 This value was specified for all of the model
combustors.
The volumetric flow rates for continuous and intermittent
.model combustors were calculated based on the flow rates
-.monitored during emissions tests of similar MWI's. A plot of
flow rate vs. actual charging rates during the tests was
19
-------
developed, and an equation for the best fit line through the data
was used to calculate the flow rates for each model combustor.27
The data from tests of both combustor designs are analyzed
together because combustion air requirements are assumed to be
the same for similar waste charging rates. As noted in
Section 2.1.4.2, the exhaust gas streams that were monitored
during the EPA and non-EPA emissions tests contained an average
02 concentration of about 14 percent.8
Flow rates for batch model combustors were estimated from
the average flow rates obtained during emission tests of four
combustors and the assumption that the ratio of flow rate to
charge rate is a constant. For the four tests, the ratio was
0.9 dry standard' cubic feet per minute per pound (dscfm/lb) of
waste charged.8'21'27 Exhaust gas 02 concentrations were assumed
to be 14 percent.
For pathological incinerators, the gas stream flow rates
were calculated based on assumed stoichiometric combustion air
requirements, the total heat output from the incinerator, excess-
a^r levels, and the gas stream moisture contents and
temperatures.27 The stoichiometric combustion air requirements
were estimated to be i.o dscf/100 Btu. The total heat output in
the gas stream from the incinerators was estimated by adding the
heat content of pathological waste (1,000 Btu/lb) and the maximum
capacities of the burners for pathological incinerators.9 Heat
losses were assumed to be zero. As indicated in Section 2.1.4.2,
excess-air levels were assumed to be 200 percent. The applicable
temperatures and moisture contents are presented earlier in this
section.
2-1-4.7 Stack Parameters. The temperature and volumetric
flow rate of the stack gas and stack dimensions are input
parameters for dispersion modeling. According to responses to
the EPA information request, the average stack gas temperature of
MWI's without add-on APCD's or heat recovery was 1500°F.8 The
same stack gas temperature was assumed for all models because
secondary chamber temperatures are similar and ductwork and stack
configurations are similar for all combustor designs. The
20
-------
volumetric flow rates were calculated by applying a temperature
correction factor to the flue gas flow rates. Stack heights for
the models were based on responses to EPA information requests.
The average heights were about 45 ft for intermittent and
continuous units and 35 ft for pathological units. The typical
height for batch units was about.30 ft. For most models, stack
diameters were determined from the responses and from test
reports.7'8 Where data were not available, stack diameters were
calculated assuming a gas velocity of 3,500 feet per minute.
2.2 CONTROL TECHNOLOGIES
Eleven control technologies were developed. One control
technology consists of combustion controls; the other 10 consist
of combustion controls in conjunction with an add-on APCD. The
APCD's are based on variations of seven basic types of equipment:
(l) venturi scrubber (VS), (2) packed bed (PB), (3) fabric filter
(FF), (4) venturi scrubber/packed bed (VS/PB), (5) dry
injection/fabric filter (DI/FF), (6) fabric filter/packed bed
(FF/PB), and (7) spray dryer/fabric filter (SD/FF). All of the
basic designs have been demonstrated to control emissions from
one or more MWI's. Each of the APCD's with an FF were also
evaluated with activated carbon injection. The specified design
and operating parameters for combustion and add-on controls and
the rationale for the specifications are presented in the
following subsections.
2.2.1 Combustion Control
This control technology consists of incinerator design and
operating parameters. For this analysis, these parameters are
defined as (1) a minimum secondary chamber operating temperature
of 1800»F whenever both the primary chamber combustion air blower
is on and the primary chamber exhaust gas temperature is above
300°F, and (2) and a minimum secondary chamber gas residence time
of 2 seconds when the gas is at 1800'F. The secondary chamber
temperature requirement applies to the cooldown phase as well as
-the burning and burndown phases, as long as the primary chamber
gas temperature and combustion air blower conditions are met. As
noted in Section 2.1.4.5 and in Tables 6 and 7, the applicable
21
-------
cooldown time is an average of 2 hr/d for intermittent combustors
and 10 hr/d for batch combustors.
2-2.2 Add-On Control Equipment
The design and operating parameters for each of the seven
basic APCD's are described in the subsections below and are
summarized in Table 9 for all of the model combustors.
Additional parameters needed for cost analyses are developed in
Section 3.0. All parameters are based on typical values provided
by vendors and on values from emission test reports.
2-2-2.1 Venturi Scrubber. The two parameters that describe
VS operation are the pressure drop through the venturi throat and
the L/G ratio (i.e., the combined liquid flow to the quench and
venturi vs. the actual gas flow into the quench). According to
two vendors, the typical pressure drop through the venturi is
about 30 inches of water column (in. w.c.)28'29 One vendor
provided liquid flow rates that were used to calculate an L/G
ratio of 6 gallons per 1,000 actual cubic feet per minute
(gal/1,000 acfm). This vendor also indicated that hydrogen
chloride (HC1) removal efficiency is nearly as good as that
achieved with a VS/PB if caustic solution is used as the
scrubbing liquid.30
2.2.2.2 Packed Bed. According to one vendor, at least two
facilities use a quench followed by a PB to control emissions
from MWI's.28 Information is not available for these facilities.
However, because the gas characteristics are essentially the same
after the quench in both PB and VS/PB devices, it was assumed
that the design and operating parameters and the HC1 removal
efficiencies for the PB system are the same as those for the
VS/PB systems, which are described below.
2-2.2.3 Venturi Scrubber/Packed Bed. The pressure drop and
L/G ratios for the VS in the VS/PB control device are the same as
those for the VS control device alone. Important PB parameters
are stoichiometric ratio (SR), L/G ratio, pressure drop, packing
height, and absorber shell diameter. Typically, caustic solution
is used as the scrubbing liquid. According to one vendor, the SR
(the molar ratio of the amount of caustic added to the amount of
22
-------
TABLE 9. CONTROL DEVICE OPERATING PARAMETERS
Model combustor no.
Control device parameters
Continuous models
No. 1 No. 2
1. Venluri
a. pressure drop. in. w.c.
b. L/G (gal/1.000 acf)
2. Fabric filter
a. bag type
b. G/C ratio, ft/min
c. cloth area, f i2
d. pressure drop, in. w.c.
Intermittent models
No. 3 No. 4 No. 5
Batch model
No. 6
Pathological model j
No. 7
3. Packed bed absorber
a. packing height, ft
b. stoichiomeiric ratio
c. pressure drop. in. w.c.
d. L/G (gal/1,000 acf)
e. shell diameter, in
FELT FELT
7 7
3.186 2,165
3 3
FELT FELT FELT
7
3,186
3
FELT
J4. Venluri/p»cked lower
a. venturi pressure drop, in. w.c.
b. packed bed pressure drop, in. w.c.
c. venturi L/G ratio
d. packed bed L/C ratio
e. stoichiomeiric ratio
f. packingheight.fi
;. shell diameter, in
IS. Dry In tecllon/f«bric filter
a. bag type
b. G/C ratio, ft/min
c. cloth area, ft2
d. FF pressure drop, in. w.c.
e. stoichiomeiric ratio
FELT
7 7
,347 530
3 3
5 5
1:1 1:1
4 4
20 20
48 30
30 30
4 4
6 6
20 20
1:1 1:1
5 5
7
320
3
5
1:1
4
20
24
30
4
6
20
1:1
J
7
592 . 1
3 1
5
1:1
4
20
30
30
4
6
20
1:1
5
on
16. Fabric filler/packed lower
a. bag type
b. G/C ratio
c. cloth area, fl2
d. FF pressure drop, in. w.c.
e. packed bed pressure drop, in. w.c
f. L/C ratio
g. stoichiometric ratio
h. packing height, ft
i7. Sprav drver/Ubrii filler
a. gas residence time in SD, s
b. stoichiometric ratio
c. bag type
d. G/C ratio
e. cloth area, f 12
f. FF pressure drop, in. w.c.
. makeup lime rale. Ib/hr (a)
t. makeup lime rale. Ib/hr (a) «.» JJ.J I ™
(a) The makeup rates are based on the stoichiometric ratio above and on the HC1 concentration used in Table 23
23
-------
caustic required to exactly neutralize all acid gases) is about
1:1 or slightly less. This ratio is specified to maintain pH at
or slightly below 7 to avoid scaling. The vendor also indicated
that the L/G ratio at the inlet to the PB is about
20 gal/1,000 saturated acfm.28 According to this vendor, the
pressure drop across the packed tower is 4 in. w.c.30 Two
vendors indicated the packing height for their absorbers is
5 feet. One vendor indicated that the packing is plastic Intalox
saddles; the other uses plastic Tellerette packing.28'31 The
absorber shell diameter is a function of the gas flow rate. The
specified shell diameters for absorbers used with each model
combustor are based on information from the vendor with larger
absorbers.28 The resulting shell diameters range from 24 in. for
the smallest combustor to 72 in. for the largest combustor. A
mist eliminator at the outlet of the PB minimizes salt carryover.
2.2.2.4 Fabric Filter. Although an FF has been used alone
to control emissions from at least two MWI's, design and
operating information for those installations is not available.
However, because the inlet gas conditions for FF and FF/PB
devices are identical, it was assumed that the parameters for an
FF device alone are the same as those for the FF in the FF/PB
device, which is described below. According to vendors, a range
of PM emission levels can be achieved, depending on the type of
bag. Membrane bags are more efficient than felt bags. For this
analysis, the FF's are based on felt bags because they are used
in most existing applications, and they are less expensive.
2.2.2.5 Drv In-iect ion/Fabric Filter. For this control
device, lime is injected into the duct between an evaporative
cooler and the FF, and a retention chamber is placed between the
injection point and the FF. Two of the four DI/FF equipment
vendors that responded to EPA information requests indicated that
lime is recycled, and the other two indicated that it is not.
Three of the vendors use a retention chamber, and the fourth
offers an FF with an extended housing that serves as a retention
chamber.32-35 All of the vendors specified a pulse-jet FF
design. The parameters presented in Table 9 are for the most
24
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common variation of the DI/FF system, which includes a retention
32 - 37
chamber but no recycle equipment.
The vendors use either evaporative coolers, gas-to-air heat
exchangers, or a combination of this equipment to reduce the gas
temperatures to between 250° and 400°F before the alkaline
reagent injection. According to the vendors, lower temperatures
maximize control of metals and polychlorinated dibenzo-p-dioxins
and polychlorinated dibenzofurans (CDD/CDF) as well as the acid
gases. For the models, a temperature of 300°F has been assumed.
The makeup lime feed rate was based on an SR of 2.5:1, which
is about the average of the values reported by two vendors that
do not recycle lime.34'35 The vendors specified this ratio for
95 and 75 percent removal of HC1 and sulfur dioxide (S02),
respectively, from a gas stream that contained HC1 and S02
concentrations of 1,200 parts per million dry volume (ppmdv) and
60 ppmdv, respectively, corrected to a 7 percent 02 concentra-
tion.32'35 For different HC1 and S02 concentrations, the lime
makeup rate would be scaled up or down as necessary to maintain
the 2.5:1 stoichiometric ratio.
An EPA-sponsored emission test of an MWI with a DI/FF
control device showed the SR had to be about 5:1 to achieve a
95 percent HC1 removal efficiency.38 However, this DI/FF control
device did not have a retention chamber. One vendor indicated
that to achieve the same results, the lime feed rate in a device
without a retention chamber might have to be two times higher
than the rate in a device with a retention chamber. Therefore,
an SR of 2.5:1 appears to be reasonable for the model DI/FF
control device.
A range of PM emission levels can be achieved with this
control device (just as for the FF alone), depending on whether
felt or membrane bags are used. The net gas-to-cloth (G/C) ratio
is specified as 3.5:1, which is about the midpoint of the range
provided by vendors and is equal to the operating ratio at one
, hospital.17'32'35 The models are based on felt bags because most
existing FF's contain felt bags, and they are less expensive than
membrane bags.
25
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The specified pressure drop for the DI/FF control devices is
9 in. w.c. This value is based on information from vendors that
the pressure drop across the FF is about 5 in. w.c. and on the
assumption that the pressure drop is 4 in. w.c. through the
combustor, evaporative cooler, and ductwork.
Data from an EPA-sponsored emissions test indicate that
injecting activated carbon before the fabric filter improves the
removal efficiency of both CDD/CDF and mercury (Hg). A carbon
injection rate that produced a carbon concentration of
338 mg/dscm reduced CDD/CDF and Hg emissions by 98 percent and
90 percent, respectively, relative to inlet concentrations.38
This carbon concentration was specified for the model DI/FF
control technology with activated carbon injection.
2-2-2.6 Fabric Filter/Packed Bed. For this control device,
as for all controls that include a FF, the gases must be cooled
before entering the FF. One vendor that offers this type of
control device uses a gas-to-gas heat exchanger before the FF. A
water spray and dilution air are also included before the heat
exchanger to provide additional cooling when needed. The exhaust
gas could be cooled solely with a water quench, but no known
FF/PB control device uses such cooling equipment. As for other
FF technologies, the specified FF is a pulse jet design, it is
assumed that felt bags are used, and the specified FF operating
temperature is 300°F. According to the permit for one facility
with this control equipment, the G/C ratio is 7:1, and the
pressure drop across the FF is about 3 in. w.c.39
The gases are cooled to saturation by caustic solution spray
in the duct between the FF and the PB. The PB parameters are
assumed to be the same as those for the PB in the VS/PB control
device. The gases leaving the PB are ducted to the gas-to-gas
heat exchanger to cool the exhaust gases from the incinerator.
The heat exchanger raises the temperature of the gases from the
PB above the dew point, which eliminates a steam plume from the
stack.
No FF/PB control device currently operates or has been
tested with activated carbon injection. Consequently, the
26
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performance.of carbon injection in a FF/PB control device is not
known. For the model and the costing analyses, however, the
carbon concentration for this control technology was assumed to
be the same as that for the DI/FF control technology.
2.2.2.7 Spray Dryer/Fabric Filter. Parameters for this
control device are based on information from one vendor that has
installed an SD/FF control device for an MWI and from two other
vendors that have produced SD/FF systems for other types of
incinerators.34'40"43 Each of these vendors indicated that lime
slurry is injected into the spray dryer vessel by a rotary
atomizer. According to two of the vendors, the gas residence
time in the spray dryer vessel ranges from 10 seconds to
18 seconds; an average of 14 seconds was specified for the
models.40'43 Gases are cooled to about 300°F in the spray dryer.
Two of the vendors specified SR's that ranged from about
2.0:1 to 3.0:1 to achieve 95 percent removal of HC1 and
75 percent removal of S02 from the gas stream described in
Section 2.2.2.S.34'42 During an EPA-sponsored emissions test,
HC1 removal efficiencies of about 99 percent were achieved with
an SR of about 2.5:I.41 Therefore, an SR of 2.5:1 was specified
for the model.
Each of the vendors uses a pulse-jet FF, and two of them
indicated that the FF parameters would be the same as those for
DI/FF devices that they also make. Therefore, the G/C ratio for
the model is 3.5:1, the pressure drops across the FF is
5 in. w.c., and felt bags are used in the FF.34'41'43
Data from the EPA-sponsored emissions test indicate that
including activated carbon in the lime slurry improves the
removal efficiency of CDD/CDF and Hg. Adding carbon at a
concentration of 188 mg/dscm reduced CDD/CDF emissions by
98 percent and Hg emissions by 90 percent, relative to inlet
levels.41 This concentration was specified for the model.
3.0 COMBUSTOR AND CONTROL TECHNOLOGY COSTS FOR NEW FACILITIES
This section presents the capital and annual costs for the
7 model combustors and 11 control technologies developed in
Section 2. All costs are in October 1989 dollars. Cost and
27
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design information was obtained from a total of nine incinerator
and eight APCD vendors; some of the vendors also provided
additional data in response to followup
requests.
2-5,6,9,23,25,28,29,31-35,44-58
This information was
used to develop the capital and annual cost algorithms that are
discussed in this section.
Many of the vendors claimed their cost data (and some design
data) to be confidential business information. Therefore,
specific references regarding the number of information sources,
design characteristics, or costs used to develop the algorithms
are not provided in this section when they contain confidential
business information. These details are presented in
Reference 59.
The remainder of this section is divided into six
subsections. Capital costs for the combustors and control
technologies are discussed in Sections 3.1 and 3.2, respectively.
Annual costs for the model combustors are presented in
Section 3.3. Annual costs for each of the control technologies
are estimated in Section 3.4. Activated carbon injection costs
are discussed in Section 3.5. A summary of the total capital
investment and total annual costs is presented in Section 3.6.
3.1 COMBUSTOR CAPITAL COSTS
The total capital investment (TCI) consists of purchased
equipment costs (PEC) and installation costs. Purchased
equipment costs for each combustor type are based on combustors
with secondary chambers that are designed for operation at 1800°F
or more with a gas residence time of l second. The model
combustors are designed for 1800°F, but they are specified with
an actual operating temperature of 1700°F because this is the
typical temperature at facilities (including those with nearly
new units) that responded to EPA requests for information.2
Installation costs were estimated to be equivalent to
48 percent of the PEC for all model combustors. This factor is
the average of values obtained from manufacturers that indicated
installation factors are between 33 and 60 percent. These
manufacturers provided cost factors for intermittent and
28
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continuous"combustors. It was assumed that installation costs
for batch and pathological combustors fall in the same range.
The equations that were developed to estimate the model
PEC's are shown in Table 10, and the TCI's for each model are
presented in Table 11. The procedures by which the model PEC's
were developed are described below.
3.1.1 Continuous Combustors
Purchased equipment costs for continuous combustors are
presented in Figure l. The data show considerable scatter. It
is not known what design or fabrication factors account for the
variation, but the data represent actual manufacturer costs.
Therefore, the model combustor costs are based on the equation of
a line that was determined by least-squares linear regression
using all of the data.
The continuous combustor costs estimated from this equation
are almost three times higher than the costs described in
Section 3.1.2 for intermittent units that have the same design
capacity. There are several design differences between
continuous and intermittent units that account for the cost
difference. Typically, the primary chamber "of a continuous unit
has at least two hearths, an ash transfer (or discharge) ram for
each hearth, a water sump into which the ash is discharged, and
an ash hoe or conveyor system to remove the ash from the sump.
Also, the hydraulic system for continuous units is larger than
that for intermittent units because it must power the ash
transfer rams and the ash hoe as well as the ram feeder.
Additional controls and instrumentation are also required for
these continuous combustor components. The shell of the primary
chamber is larger for continuous units because it encompasses the
sump. Other differences between continuous and intermittent
units are unique to individual manufacturers. For example, one
manufacturer incorporates an underfire cooling system
(recirculating water piping, pump, and water-to-air heat
exchanger) in continuous units. Air shrouds on the primary and
secondary chambers to preheat secondary chamber combustion air
are included by one manufacturer. At least one manufacturer uses
29
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TABLE 10. EQUATIONS TO ESTIMATE PURCHASED EQUIPMENT
COSTS FOR MODEL COMBUSTORS
Combustor type
Intermittent
Continuous
Batch
Pathological
Purchased equipment cost equation3
$ = 5,817 x (lb/hr)°-4537
$ = 174.2 x (Ib/hr) + 177,740
$ - 31.3 x (Ib/batch) + 32,775
$ = 216 x (Ib/hr) + 21,898
Regression
value , R
0.75
0.44
0.98
0 .62
design capacities are used in these equations
TABLE 11. SUMMARY OF MODEL COMBUSTOR CAPITAL COSTS
Combustor design
Continuous
Intermittent
Batch
Pathological
Combustor
capacity
1,500 Ib/hr
1,000 Ib/hr
1,500 Ib/hr
600 Ib/hr
200 Ib/hr
500 Ib/batch
200 Ib/hr
Model
combustor
1
2
3
4
5
6
7
Model combustor costs
Purchased
equipment cost,
$
439,040
351,940
160,580
105,961
64,369
48,425
65,098
Total capital
investment,
$a
650,000
521,000
238,000
157,000
95,300
71,700
96,300
aThe PEC was multiplied by 1.48 to estimate the TCI. This factor
accounts for the installation costs, and it is based on information from
incineration manufacturers that estimated installation costs to be
between 33 and 60 percent of the purchased equipment costs.
30
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thicker and/or different refractory and insulation in continuous
units. One manufacturer includes temperature zone controls only
in the primary chamber of continuous units. One manufacturer
designs a continuous unit with a Pulse-Hearth™ primary chamber.
3.1.2 Intermittent Combustors
Purchased equipment costs for intermittent combustors are
presented in Figure 2. Except for three of the small combustors,
the cost for an automatic feed mechanism is included in the costs
that were obtained from the manufacturers. Since the models
include automatic charging equipment, ram feeder costs were
estimated for the three small units based on information from
other manufacturers. One manufacturer indicated that one unit
has a top loading mechanism, and the cost for this equipment is
about the same as a ram feeder.47 The model combustor costs are
estimated from the equation for the best-fit curve, which was
determined from a power function through the data.
The costs for two combustors (385 Ib/hr and 765 Ib/hr units)
appear to be extreme outliers. The sizes for the these
combustors are based on the actual burn rate rather than the
maximum charge rate, which other manufacturers have used.
Accounting for this difference would increase the sizes of these
units by 20 percent, but that is not enough to bring their costs
into line with the others. Other factors that could explain why
these two units cost significantly more than other combustors are
not known. Since a majority of the costs are much lower, these
two data points are not included in the analysis.
3.1.3 Batch Combustors
Purchased equipment costs for three batch combustors are
presented in Figure 3. The costs do not include an automatic ram
feeder because a ram is not available on the small and midsize
units, and it is only an option on the large unit. The model
combustor PEC's are based on a least-squares linear regression
line through the data.
3-1.4 Pathological Combustors
The manufacturers provided information for two types of
pathological combustors: "hot-hearth" and "dual-purpose"
32
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designs. Purchased equipment costs for both designs are shown in
Figure 4. Some of the costs for dual-purpose units designed for
pathological waste were estimated from costs that the
manufacturers provided for the intermittent version and from
estimates that some of the manufacturers provided for the cost
difference between the two designs. Most of the cost difference
is for larger, or additional burners in the pathological design.
Purchased equipment costs for the model pathological combustors
were estimated from the equation for a least-squares linear
regression line drawn through the data.
3.2 CONTROL TECHNOLOGY CAPITAL COSTS
This section presents costs for the combustion control
technology described in Section 2.2.1 and for the seven add-on
control technologies without activated carbon injection that are
described in Section 2.2.2. Costs for the three FF-based control
technologies that incorporate activated carbon injection are
described in Section 3.5.
3.2.1 Cgmbustion Control Costs
All of the combustor manufacturers that responded to EPA
information requests indicated that the design operating
temperatures are 1800°F or more. Therefore, it was assumed that
an 1800°F control parameter would not result in higher PEC's.
Most of the combustor manufacturers that responded to EPA
information requests also provided costs both for combustors with
secondary chambers that have a 2-second residence time and for
combustors that have a 1-second residence time. Most of the data
are for intermittent and continuous combustors. The data for
these two combustor designs were evaluated in a single analysis,
and the results were used to estimate combustion control costs
for all of the model combustors. A single approach was used to
simplify the analysis. Also, the secondary chamber costs should
be the same for any combustor type assuming similar gas stream
temperatures and moisture contents (and similar secondary chamber
designs). The model combustors are based on these assumptions.
The first step in the analysis was to estimate gas flow
rates for the combustors that were identified by the
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manufacturers. These flow rates were estimated by the same
procedure described in Section 2.1.4.6. Figure 5 shows the
resulting flow rates in dry standard cubic feet per minute
(dscfm) plotted versus the additional PEC's for the larger
secondary chambers. The best-fit line through the data was
determined by linear regression. The line and the equation for
it are also shown in Figure 5. Installation costs are assumed to
be equal to 48 percent of the PEC--the same factor as that used
to estimate installation costs for the complete combustors. The
PEC, installation cost, and TCI for all of the model combustors
are shown in Table 12.
TABLE 12. COMBUSTION CONTROL COSTS FOR MODEL COMBUSTORS
Model
combust or
1
2
3
4
5
6
7
Purchased
equipment
cost, $
43,433
31,812
43,433
22,512
13,213
11,905
13,925
Combustion control capital
costsa
Installation
cost, $
20,848
15,270
20,848
10,806
6,342
5,715
6,684
Total capital
investment, $
64,300
47,100
64,300
33,300
19,600
17,600
20,600
aCombustion control capital costs are equal to the difference
between costs for combustors that have secondary chambers
with 2-second residence times and costs for combustors that
have secondary chambers with 1-sec residence times.
3.2.2 APCD Control Costs
The TCI's for most of the APCD technologies were estimated
by a two-step procedure. First, algorithms were developed to
estimate TCI's for two or three different sizes of control
devices from each vendor (vendor algorithms). Second, the
results of the vendor algorithms were averaged to develop a
generic algorithm for any size of the control device.
Differences from this approach are described in the appropriate
subsections below.
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The vendor algorithms are based on the quoted costs from
vendors in response to EPA information requests and estimated
costs for additional items the vendors do not provide or for
which they neglected to provide costs. The EPA information
requests specified the composition of three MWI gas streams (the
flow rates varied, but the temperature and pollutant
concentrations were identical) and asked for the design and cost
of APCD's that the vendors produce to control emissions from such
MWI gas streams. The vendors quoted costs for five of the seven
control devices evaluated in this analysis. These five APCD
designs are the DI/FF, FF, VS/PB, PB and SD/FF devices.
Equipment component costs and installation costs were also
obtained from some vendors. Costs for the VS and FF/PB control
devices were estimated by eliminating, reducing, or combining
component costs from the first five APCD's.
To develop the TCI for each control device, the vendor
algorithms also include procedures to estimate costs for a bypass
damper in the stack, ductwork between the incinerator and the
control equipment, foundations, taxes, and (in most cases)
freight. Costs for items like startup and contingencies also
were estimated when vendors did not provide them. All of these
estimated costs were based on standard procedures found in the
OAQPS Control Cost Manual and on some assumptions.
Assumptions used in ductwork calculations for all control
devices are (1) 20 ft of carbon steel duct with one elbow are
necessary, (2) the duct is lined with 6 in. of refractory, and
(3) the gas velocity is 4,000 ft/min. Based on data limitations
in the n&QPS cont™i Post Manual, it was assumed that both the
dump stack and the bypass damper costs would be constant
(independent of diameter) for diameters up to 24 in. even though
the ductwork was estimated to be as small as 8 in. for small MWI
gas streams.60 The costs for these components are the same for
each control device applied to a particular model combustor.
Taxes and freight costs were estimated to be 3 and
5 percent, respectively, of the equipment costs. Foundations
were estimated to be 2 percent of PEC's for DI/FF and FF control
39
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devices, 5 percent for wet control devices, and 4 percent for
FF/PB and SD/FF control devices. Before these costs were
estimated, it was necessary to estimate the equipment costs.
When equipment costs were not available separate from
instrumentation and installation costs, the OAQPS procedures were
used to estimate the percentage of the total costs comprised by
equipment costs.
For convenience, the TCI is used instead of the PEC in the
vendor algorithms. Vendors often provided costs that varied with
the size of the equipment, and other times the installation costs
had to be estimated from the total costs (as described above).
Therefore, it was easier to evaluate installation costs as part
of the individual control device TCI in each vendor algorithm,
rather than trying to develop an average installation factor to
apply to the results of a generic PEC algorithm.
The generic algorithms are based on linear regression
analyses of the TCI data from the vendor algorithm plotted vs.
gas flow rate in dscfm at the inlet to the APCD. The results are
shown in Figures 6 through 12. The figures for the VS/PB, vs,
DI/FF, FF, and SD/FF control devices show a shaded area that
represents the range of costs from the vendor algorithms. The
bounds of the shaded area have been extrapolated linearly on
figures that have only one data point for the smallest control
device. The line bisecting the shaded area shows the best fit
line through the data as determined by least-squares linear
regression analysis. The figures for the PB and FF/PB control
devices show only individual points and the regression line
because the costs for these devices were estimated from the
regression analyses of other control devices. The equations for
the regression lines are shown on each figure and in Table 13.
These equations were used to estimate the costs of the control
devices as applied to the model combustors.
3-2.2.1 Wet Control Dgv^ft Vendors that responded to EPA
requests for information about wet control devices provided costs
for the VS/PB and PB control devices. Most of these vendors
produce packed bed absorbers, but one produces a tray tower
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TABLE 13. EQUATIONS TO ESTIMATE TOTAL CAPITAL
INVESTMENT FOR APCD'S
APCD
DI/FF
FF
VS/PB
VS
PB
FF/PB
SD/FF
DI/FF w/carbon
FF/PB w/carbon
SD/FF w/carbonb
Total capital investment cost equation
$ = 63.8 x (dscftn) + 407,498
$ = 47.0 x (dscfin) + 306,720
$ = 33.3 x (dscfm) + 118,969
$ = 30.4 x (dscftn) + 100,110
$ = 27.6 x (dscftn) + 109,603
$ = 76.7 x (dscftn) + 381,928
$ = 179.7 x (dscftn) + 701,268
$ = 63.8 x (dscftn) + 407,498 + 4,500 x (dscftn/ 1, 976)° -6
$ = 76.7 x (dscftn) + 381,928 + 4,500 x (dscftn)/! ,976)°-6
$ = 179.7 x (dscftn) + 701,268
Regression
value, R^
0.33
0.37
0.60
0.81
a
0.98
0.19
fThe PB costs are estimated as a percentage reduction from the regression line for VS/PB costs.
"No additional capital costs are incurred when using carbon in a SD/FF system.
48
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absorber. "The two devices are analyzed together because both are
designed primarily to remove acid gases, and it was assumed that
the pollutant removal efficiencies are similar for the two
devices. Most of the vendors that responded provided the TCI for
the devices that they produce. Some vendors also provided
installation costs and some component equipment costs. Missing
equipment costs and installation costs for any of the vendors
were estimated based on standard factors in the OAOPS Control
mst Manual and/or on component costs from other vendors. These
VS/PB control device costs were used as the starting point for
estimating capital costs for all wet control options.
Two of the vendors identified design (maximum) inlet gas
flow rate capacities for -off-the-shelf" control devices that
they would use for the gas streams specified in the EPA
information requests. Therefore, when costs from these vendors
are used in this analysis, they are associated with the control
device flow rates rather than the gas stream flow rates from the
information requests.
3 2.2.1.1 vgnMiri scr">*"»T-/Paeked Bed. The range of VS/PB
control device costs are shown in Figure 6. The equation of the
line through these data was determined by linear least-squares
regression, and it is also shown in Figure 6.
At least some of the costs differences in Figure 6 are due
to known design differences. The costs at the upper bound of the
range are for systems with a higher horsepower (hp) fan, more
corrosion resistant construction materials in some components,
redundancy (e.g., backup pumps), and the more extensive use of
automatic controllers. Also, one vendor indicated that
additional packing in the PB (in the same shell) would be
required to increase the removal efficiency from the 90 percent
specified in the EPA information request to the 99 percent that
other vendors claimed. All costs were used in the analysis
: because available data do not show any of these systems to be
.- either over or under designed.
3 2 2.1.2 v«mMiTM scrubber. Estimated costs for VS control
..
devices are presented in Figure 7. The control device costs were
49
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estimated by eliminating or reducing component costs from the
costs for the VS/PB control device (see Section 3.2.2.1.1). The
main cost savings were realized by subtracting the absorber
costs. The cost of caustic solution circulation equipment was
reduced based on the eliminated flow to the absorber.
Instrumentation and installation costs were also reduced. A
small cost was added for a 4-pass, chevron-blade mist eliminator
to minimize salt carryover.
3.2.2.1.3 Packed Bed. Estimated costs for PB control
devices are presented in Figure 8. Some of the vendors that
provided VS/PB system costs also provided PB device costs. The
differences between VS/PB and PB costs (in percent) from these
vendors were plotted vs. the inlet gas flow rate (in dscfm), and
an equation for the line through these data was determined by
linear regression. The differences range from about 9 percent
for small systems, to 11 percent for medium systems and
14.5 percent for large systems. The PB costs were then estimated
by applying these percentages to the linear regression equation
for the VS/PB costs.
3-2.2.2 Control Devices with an FF.
3.2.2.2.1 Dry in-iection/fabric filter. Vendors that
responded to EPA information requests provided TCI costs for two
DI/FF configurations. One group of vendors described systems
with lime recycling; others did not. These vendors also
estimated costs for at least some of the components in their
DI/FF control devices. The system components on which the costs
are based include equipment to reduce the gas stream temperature,
dry lime injection into the ductwork, a reaction or retention
chamber after the injection point to increase contact time
between the lime and the acid gases, a pulse-jet FF, lime
recycling equipment, an I.D. fan, and a stack.
Even though the vendors produce equipment based on the same
basic design, many features are unique to each system. For
example, gas cooling is accomplished with evaporative coolers,
gas-to-air heat exchangers, and a combination of an evaporative
cooler with a gas-to-air heat exchanger. The cooled gas stream
50
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temperatures range from 250°F for one vendor to 400°F for another
vendor. The G/C ratios range from 2.6 for one vendor to 4.3 for
another. A few of the large and midsize systems have multi-
compartmented FF's; all other FF's have a single compartment.
Some vendors specified lime recycling equipment. Three of the
vendors included a retention chamber, and a fourth vendor offered
an FF with an extended housing, which was assumed to serve the
same function as a retention chamber.
The range of DI/FF costs and the equation of the line
through the data that was determined by linear least-squares
regression are shown in Figure 9. This analysis is based on
DI/FF systems without lime recycle because lime is not recycled
in most of the existing DI/FF control devices. Therefore, costs
for lime recycling equipment were estimated and subtracted from
the total costs provided by vendors that use such equipment.
According to one vendor, lime recycling equipment costs comprise
about 4 percent of the TCI for the large and midsize models and
l percent for the small model. The lime recycling equipment
costs comprise a smaller percentage of the TCI for the small
model because a simpler design can be used. It was assumed that
the same percentages are valid for estimating lime recycling
equipment for other vendors.
The costs from one vendor are not included in the graphical
analysis because gas cooling is accomplished in the APCD with a
gas-to-air heat exchanger and a flue gas recirculation system
that are not employed by other vendors. The designs from other
vendors can achieve this same gas cooling, apparently at a much
lower cost. Furthermore, even though the vendor claims higher
HC1 removal efficiencies, it is believed that the other vendors
can also achieve these efficiencies by increasing the lime makeup
feed rates (i.e., by increasing the stoichiometric ratio). As
Figure 9 shows, the costs from the other vendors also vary
significantly. The unique features described earlier in this
section account for some, if not all, of the variation. However,
available data do not show any of these systems to be either over
or underdesigned.
51
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3.2.2.2.2 Fabric filter. Costs for FF control devices are
presented in Figure 10. The costs were estimated by subtracting
DI equipment costs from the total DI/FF equipment costs. If the
vendor provided DI equipment costs, they were subtracted directly
from that vendor's DI/FF costs. Otherwise, the DI equipment
costs were estimated by assuming they comprise the same
percentage of the total equipment cost as for other vendors. For
each vendor, the ratio of installation-to-equipment costs was
assumed to be the same for the FF control option as for the DI/FF
control option.
3.2.2.2.3 Fabric filter/packed bed. The FF/PB control
device consists of gas-cooling equipment (a gas-to-gas heat
exchanger with water spray and dilution air) that reduces the gas
temperatures to 300°F, FF, in-line quench that further reduces
the gas temperature to saturation (about 132°F), PB,
recirculating liquid and neutralization systems, I.E. fan, and
stack.
No vendor provided costs for a FF/PB control device.
Therefore, component costs from other control devices were
combined to estimate the FF/PB costs. The costs for the PB and
all auxiliary equipment except the FF and heat exchanger were
estimated by using the following simplified two step process.
First, costs were developed for VS/PB control devices that would
be used for lower flow rates (i.e., the flow rate out of the heat
exchanger that is used in the FF/PB control device is less than
that out of the evaporative quench that is used in the VS/PB
control device). The second step was to subtract estimated VS
and related auxiliary equipment, instrumentation, and
installation costs from the new VS/PB costs.
Fabric filter costs were estimated based on FF costs from
one of the DI/FF vendors. Since costs for the unique gas cooling
equipment described above were not available, the costs were
assumed to be similar to those for a gas-to-air heat exchanger
used by one of the EI/FF vendors to cool exhaust gas from 1800°
to 300°F. Instrumentation and installation costs were also
estimated for the heat exchangers and FF's based on the
52
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installation cost factors provided by the respective vendors for
their complete DI/FF system. The resulting FF/PB costs are shown
in Figure 1.1.
3>2.2.2.4 Spray dry^r/fabric filter. The range of SD/FF
costs and the equation of the line through the data that was
determined by linear least-squares regression are shown in
Figure 12. These costs are for SD/FF systems that consist of a
spray dryer absorber vessel, lime slurry mixing tank(s), slurry
piping, rotary atomizer, pulse-jet FF, I.D. fan, and stack. In
each system, the spray dryer reduces the gas temperature to about
300°F, but the residence times range from 10 to 18 seconds. The
G/C ratios range from 2.8:1 to 4.2 si. These design differences
account for at least some of the range in costs.
3.3 COMBUSTOR ANNUAL COSTS
Estimated annual costs for the model combustors are shown in
Table 14. The costs are based on the operating hours for each
model combustor as described in Tables 6 through 8. Other
information that was used to develop each of the costs is
described in the subsections below. A copy of the algorithm for
intermittent combustors is presented in Appendix A.
3.3.1 Electricity
Three combustor manufacturers provided connected horsepower
ratings for intermittent and continuous combustors, although most
of the data were obtained from one manufacturer. These ratings
were for combustion and burner air blowers, the feed ram motor,
and, where applicable, the ash ram motor. Least-squares linear .
regression analyses were performed with both complete data sets,
and the resulting equations were used to estimate the horsepower
requirements for the model combustors. Figure 13 shows the data
and equations. A similar analysis was performed with data for
the combustion and burner air blowers that were obtained from one
batch combustor manufacturer. These data and the resulting
equation are shown in Figure 14. Horsepower requirements for
pathological combustors were assumed to be the same as those for
intermittent combustors.
53
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Electricity costs were estimated by assuming all of the
motors were running continuously during all operating hours
(including 2 hr of cooldown for intermittent units and 10 hr of
cooldown for batch units). This assumption overestimates the
cost because the feed and ash rams do not operate continuously.
Electricity costs were assumed to be $0.06 per kilowatt-hour
(Kwh).28,32,33
3.3.2 auxiliary Fuel
Auxiliary fuel costs are based on the type of fuel, the
burner capacities, and the burner utilization rates. Natural gas
was specified as the auxiliary fuel for all of the models because
it is used in nearly all existing MWI's.?'12'13'22 Natural gas
costs were assumed to be $0.35/therm, which is
$3.5/1,000,000 Btu.25 t
Burner capacities for all combustor designs were obtained
from one manufacturer each. The equation for the best-fit line
through each data set as determined by least-squares linear
regression was used to estimate burner capacities for the model
combustors. .
During the preheat phase, the secondary chamber burner is on
continuously in all combustors. Because of its lower setpoint
temperature, the primary chamber preheat for intermittent,
continuous, and pathological combustors may be completed before
the secondary chamber preheat. If so, the primary chamber burner
will cycle on and off to maintain the setpoint temperature until
the first charge is introduced. The primary chamber is not
preheated in batch combustors.
After the first few charges during the burning phase, the
primary chamber burner is typically off in intermittent and
continuous combustors, as long as waste is charged regularly
(although it can be significantly below the design rate). For
batch combustors, the primary chamber burner fires for a preset
time period (about 60 seconds) to ignite the waste; it then turns
off. in pathological incinerators, the primary chamber burner
cycles on and off as necessary. During the burning phase, the
secondary chamber burners in all combustors cycle on and off or
57
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between high- fire and low- fire as necessary to maintain the
setpoint temperature.
During burndown, burners in the primary chamber of
intermittent, continuous, and pathological combustors may also
cycle on and off or between high- fire and low- fire as needed to
maintain setpoint temperatures. In batch combustors, the primary
chamber burner remains off. The secondary chamber burner cycles
in all combustors.
Fuel consumption rates during preheat were estimated by
assuming the secondary chamber burners for all combustor types
are on 100 percent of the time; the primary chamber burner was
also assumed to be on 100 percent of the time, except in batch
units, where it is off. During the burning phase (or the "low-
air" phase for batch units) , the secondary chamber burner was
assumed to be on 50 percent of the time in all combustor types;
the primary chamber burner was assumed to be on 50 percent of the
time in pathological units, and it was assumed to be off in the
others. During burndown (or the high-air" phase for batch
models), the primary chamber burner was assumed to be on
75 percent of the time in all except batch units, where it is
off. The secondary chamber burner was assumed to be on
90 percent of the time during burndown in all combustors.
3.3.3 Water
Three manufacturers indicated the water injection rates for
cooling the primary chamber in intermittent and continuous
combustors. The highest of the three flow rates was used in the
analysis. Even so, the annual water cost is minor. Water costs
were estimated to be $0.77/1,000 gallons.61
3.3.4 Operatin
Based on observation of operators at several facilities, it
was estimated that, for all combustor types except batch units,
operators spend about 50 percent of their time tending to the
incinerator during the burning phase. For .the batch model, it
was assumed that operators spend about l hour to start the unit,
add the waste, and monitor the process. For both intermittent
and batch combustors, an additional 0.25 to l hour was allocated
58
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for ash removal, depending on the combustor size. Operator wage
rates were assumed to be $l2/hr--the same as the rate for MWC
62
operators.
3.3.5 Supervisory Labor
According to the QAOP5 Control Cost Manual, the cost for
supervisory labor is about 15 percent of the operating labor
cost.63
3.3.6 Maintenance Labor
According to the n&QPS Control Cost Manual, maintenance
labor requirements for air pollution control incinerators are
about 0.5 hr/8-hr shift, and the"wage rate is 10 percent higher
than the operator wage rate.64 The maintenance labor
requirements were assumed to be the same for MWI's.
3.3.7 Maintenance* Materials
Annual maintenance materials costs are assumed to be equal
to 2 percent of the TCI.
3.3.8 Ash Disposal
Based on information from EPA-sponsored emissions tests, the
weight of the ash that is removed from the combustor is 9 percent
of the waste charged.15'17 The costs to dispose of ash in a
municipal waste landfill were estimated to be $40/ton in
October 1989 dollars. This cost is based on an estimated cost in
June 1991 of $43/ton and an assumed inflation rate of 5 percent
per year.65
3.3.9 Refractory Replacement
Equations to estimate the annual costs for replacing the
primary and secondary chamber refractory were developed from the
installed refractory cost and the capital recovery factor (CRF).
The installed refractory costs are a function of the volume and
configuration of the chambers, the thickness of the refractory,
and the unit cost to purchase and install 1 cubic foot (ft )
material. Each of these parameters is discussed below.
Typically, the walls of the primary and secondary chambers
are lined with either high-strength, castable refractory or high-
heat-duty firebrick. Most manufacturers also add an insulating
mineral wool block and/or ceramic fiber mat on top of the
59
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refractory; one manufacturer, however, circulates air between the
primary chamber refractory, which is attached to an inner shell,
and the outer shell. The refractory thickness in both chambers
ranges from 3 to 6 in., depending on the manufacturer and the
capacity of the combustor. Insulation thickness ranges from 1.5
to 3.0 in. For this analysis, it was assumed that the refractory
and insulation thicknesses in both chambers are 4.5 and 2.0 in.,
respectively, for all models.
Primary and secondary chamber volumes are based on
information from manufacturers, other model combustor parameters,
and assumptions. The model primary chamber volumes are based on
information from manufacturers of batch, intermittent, and
continuous combustors. This information is shown, along with the
equations that were determined by linear regression, in
Figures 15 through 17. It was assumed that primary chamber
volumes for pathological model combustors are similar to those
for intermittent combustors because dual-purpose units are more
common than hot-hearth designs. Secondary chamber volumes for
all model combustors are based on the gas stream flow rate and
the 1-second residence time.
The interior dimensions of the primary and secondary
chambers are based on information from one manufacturer,
observations of existing units, and assumptions. Typically, both
chambers are enclosed in cylindrical shells. According to one
manufacturer, the internal length-to-diameter (L/D) ratio is
about 1.5 for horizontal primary chambers.66 Based on
observations of vertical primary •chambers, the height is about
1.5 times the diameter. It was assumed that the L/D ratio is 2:1
for all secondary chambers. Although designs are unique to each
manufacturer, the refractory volumes for both chambers in all of
the model combustors were estimated based on the chamber volumes
and this dimensional information.
Unit costs for refractory and insulation (material plus
installation costs) were obtained from the OAOPS Control Co^t-.
MftBVa* and updated from December 1977 to October 1989 costs using
the CE plant cost indexes.67'68 The resulting costs are $l27/ft3
60
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and $43/ft3 for refractory and insulation, respectively.
According to manufacturers, the average refractory life is about
8 years (although they indicated a range from 2 to 15+ years).
The CRF based on this life and an interest rate of 10 percent is
0.18744.
3.3.10 Overhead
According to the OAOPS Control Cost Manual. overhead costs
are about 60 percent of all labor and maintenance material
costs.69
3•3•11 Property Tax. Insurance, and Administration
According to the OAOPS Control Cost Manual, annual costs for
these.items amount to about 4 percent of the total capital
investment.69
3 .3.12 Capital Recovery
According to MWI manufacturers, the combustor life
expectancy is about 20 years. The CRF, 0.11746, was based on the
life expectancy and an interest rate of 10 percent. This factor
was multiplied by the TCI, minus the initial refractory cost, to
estimate the capital recovery.
3.4 CONTROL TECHNOLOGY ANNUAL COSTS
This section presents annual costs for the same combustion
and APCD control technologies for which capital costs were
estimated in Section 3.2. Annual costs for FF-based control
devices with activated carbon injection are presented in
Section 3.5.
As indicated above, combustion controls are based on a
larger secondary chamber with a gas residence time of 2 seconds
and an operating temperature of 1800°F. Increasing the
temperature increases the flow rate through the APCD because more
water would need to be evaporated to cool the gas stream. The
flow would also increase because additional combustion air is
added with the additional natural gas. However, the impact on
the flow rate is small (about 5 percent), and it was assumed that
the same size APCD equipment could be used for an MWI with or
without combustion controls.
64
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and
3.4.1 fnmbustinn Control Annual Costs
The additional capital cost for the larger secondary chamber
results in additional maintenance, overhead, property tax,
insurance, administration, and capital recovery costs. These
costs were calculated by the same procedures described in
Section 3.3. Refractory replacement costs are also higher,
they were calculated by the same procedure described in
Section 3.3.9, except with twice the chamber volume.
Annual fuel costs were estimated for two additional
auxiliary fuel requirements. First, additional fuel is required
to maintain 1800°F rather than 1700°F in the secondary chamber.
Second, additional fuel is needed to maintain the temperature at
1800°F for an average of 2 hours during cooldown in intermittent
models and for 10 hours in batch models.
The resulting combustion control annual costs for each of
the model combustors are presented in Table 15. A copy of the
.combustion control cost algorithm is presented in Appendix B.
3.4.2 Wet Control Device Annual Costs
Direct and indirect annual costs were estimated for wet
control devices as applied to all of the model combustors.
Direct annual operating costs were estimated for electricity for
the fan and scrubber water pump (the items that consume nearly
all of the electricity required by the system, according to two
vendors), makeup scrubber water, operating and supervisory labor,
maintenance labor and materials, caustic, and sewage disposal.
Indirect annual costs were estimated for overhead, property tax,
insurance, administrative charges," and capital recovery.
The equations used to estimate many of the annual costs are
functions of the gas flow rate into the control system. In
addition, each of the direct costs and the overhead cost are
functions of the annual hours of operation. The annual costs for
all control devices are based on the operating hours for each
model combustor as described in Tables 6 through 8. The basis
for each cost is described below. The operating parameters for
the VS/PB control device were used as the starting point for VS
and PB control device operating parameters and annual costs. The
65
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formulas developed to calculate the annual costs for each wet
control device are shown in Tables 16 to 18. Tables 19 through
21 present the APCD annual costs for each wet control device as
applied to each model combustor. A copy of the algorithm showing
the calculations and resulting equations for the VS/PB control
device is presented in Appendix C.
3.4.2.1 Venturi Srmbber/Packed Bed. As indicated in
Table 9, the typical pressure drop is 30 in. w.c. through the
venturi throat and 4 in. w.c. through the PB. It was- assumed
that the pressure drop through the rest of the system is 4 in.
w.c.
3.4.2.1.1 T?an electricity. The annual electricity cost for
the fan is a function of the fan hp and the unit electricity
cost. The fan hp values used in the algorithm were determined by
the same method used to develop the capital costs (i.e., the hp
requirements reported by the vendors were plotted versus the gas
flow rate in dscfm, and the equation for the line through the
OQ OQ ^ T_ 4. 5
averages was determined using linear regression) . ' ' '
Figure 18 presents the reported data and the line determined by
linear regression. A unit cost of $0.06/kWh was provided by
three vendors.28'32'33
3.4.2.1.2 P"™P electricity. The annual electricity cost
for the scrubber water pump was estimated by the same procedure
as that described above for the fan electricity. Figure 19
presents the pump hp values reported by one vendor versus the gas
flow rate.28 Also shown is the equation developed by linear
regression for the line through the data. The vendors use from
one to three pumps to circulate liquid. The algorithm is based
on only one pump because the highest horsepower ratings were
reported by the vendor that uses only one pump.
3.4.2.1.3, srrubber makeup water. The makeup water costs
are a function of the makeup flow rates and the unit cost for
water. The makeup water requirements were estimated by the same
procedure as that described above for the electricity
requirements. Figure 20 presents the reported makeup rates
versus the gas flow rates in dscfm and the line determined by
67
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least-squares linear regression through the averages of the
reported values. The reported makeup rates were based on the
amount of water needed to replenish losses due to evaporation in
the quench and to replace blowdown losses. The evaporation rates
are for cooling the exhaust gas (10 percent moisture and 1800°F)
to saturation. Blowdown rates are presented in
Section 3.4.2.1.9. Based on a 1989 estimate from the American
Water Works Association, water was assumed to cost
$0.77/1,000 gal.61
3.4.2.1.4 Operating labor. Vendors estimated that average
operating labor rates are about 0.4 hr/8-hr shift. A labor wage
rate of $12/hr was used to be consistent with the rate for
incinerator operators.
3.4.2.1.5 Supervisory labor. According to the OAQPS
Control Cost Manual procedures, the supervisory labor is
estimated as 15 percent of the operating labor.
3.4.2.1.6 Maintenance labor. Vendors estimated that
maintenance labor requirements would be about 0.3 hr/8-hr shift.
The wage rate was assumed to be 10 percent higher than the
operating labor wage rate based on the QAQPS Control Cost Manual
en
procedures. *
3.4.2.1.7 Maintenance materials. The annual maintenance
materials costs were estimated by two vendors to be about
2 percent of the TCI.28'29 The algorithm uses this approach
rather than the OAQPS procedure, which is to equate the materials
cost with the maintenance labor cost, because the OAQPS procedure.
estimates a very low cost considering the size and cost of the
control systems.
3.4.2.1.8 Caustic. The sodium hydroxide (NaOH) costs are a
function of the exhaust gas flow rate, the uncontrolled
concentrations of acid gases, the NaOH-to-acid gases molar ratio,
and the dry NaOH unit cost. Hydrogen chloride is the only acid
gas evaluated in this analysis because EPA-sponsored emissions
test of MWI's showed VS/PB devices did not reduce the low
concentrations of S02- Uncontrolled HC1 concentrations range
from 120 ppm at 7 percent 02 to 1,460 ppm at 7 percent O2,
77
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depending on the type of waste burned and the combustor design.
As indicated in Section 2.2, only enough NaOH is added to keep
the pH at or just below 7.0. Therefore, the NaOH-to-HCl molar
ratio is essentially 1:1. Caustic costs of $400/ton and $375/ton
were provided by two vendors.28'29 The higher unit cost was used
in the algorithm.
3.4.2.1.9 Sewage disposal. The sewage disposal costs are a
function of the blowdown rate and the unit cost for disposal.
The blowdown rates used in the algorithm were developed by the
same procedure used to estimate fan hp requirements. Figure 21
presents the reported data as well as the line determined by
least-squares linear regression through the average of the
reported values. Vendors estimated blowdown rates based on the
acid gases concentrations that were provided in the EPA
information requests (1,200 ppm HC1 and 60 ppm S02 at 7 percent
02) and on their guaranteed removal efficiencies. Differences in
blowdown rates that may result from different uncontrolled acid
gases concentrations or removal efficiencies, were neglected in
this analysis because they have only a small impact on the cost.
One vendor estimated that sewage disposal costs are about
$2/1,000 gal.28
3.4.2.1.10 Overhead.' According to OAQPS procedures,
overhead is estimated as 60 percent of the operating,
supervisory, and maintenance labor and the maintenance
materials.69
3.4.2.1.11 Property tax, insurance, and administrative.
According to OAQPS procedures, these costs are estimated as
4 percent of the TCI.69
3.4.2.1.12 Capital recovery. According to the vendors, the
equipment life expectancy is between 15 and 20 years. The CRF,
0.11746, was based on a 20-year life expectancy and an interest
rate of 10 percent. This factor was multiplied by the TCI to
estimate the capital recovery.
3.4.2.2 Venturi Scrubber. The fan hp requirements and
electricity costs are 10 percent lower for this control device
than for the VS/PB control device described above
78
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(Section 3.4.2.1} because removal of the absorber reduces the
system pressure drop by about 10 percent. The pump hp and
electricity cost are 55 percent lower because three vendors
indicated that about 55 percent of the total liquid flow is'to
the absorber in VS/PB control devices.28'29'31 Maintenance
materials and indirect costs are lower than those for the VS/PB
control device because the capital costs are lower. Other annual
costs are the same as those for the VS/PB control device. The
annual cost equations are presented in Table 17, and the costs as
applied to the model combustors are shown in Table 20.
3.4.2.3 Packed Bed. Removing the VS from the VS/PB control
device reduces the system pressure drop and, thus, the fan hp and
electricity cost by about 80 percent. The pump hp and
electricity cost for this control device are 30 percent lower
than those for the VS/PB device. This reduction is based on
information from two vendors that 30 percent of the liquid flow '
in the VS/PB control device, is to the venturi.29 •31 Maintenance
materials and indirect costs are lower because the capital cost
is lower than that for the VS/PB control device. Other annual
cost components are the same as those for the VS/PB device. The
annual cost equations are shown in Table 18, and the costs as
applied to the model combustors are shown in Table 21.
3.4.3 Annual Costs for Control Devices with an FF
Direct and indirect annual costs were estimated for DI/FF,
FF, FF/PB and SD/FF control devices for all of the model
combustors. It was assumed that the DI/FF and FF control devices.
have an evaporative cooler to reduce the combustor exhaust gas to
300°F; the spray dryer also reduces the gas temperature to 300°F.
It was also assumed that all four control devices have an FF with
a G/C ratio of 3.5.
3.4.3.1 Dry In-iaction/Fabric Filter. Direct annual costs
were estimated for electricity, makeup lime, evaporative cooler
water, operating and supervisory labor, maintenance labor and
materials, compressed air for the FF, dust disposal, bag
replacement, and cage replacement. Indirect annual costs were
estimated for overhead, property tax, insurance, administrative
80
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charges, and capital recovery. Information about many of the
operating parameters was obtained from vendors; other parameters
were estimated. The basis for each cost is described in the
subsections below. The formulas developed to calculate the
annual costs are shown in Table 22. Most of the equations are a
function of the gas flow rate into the control device and many
are also related to the annual hours of operation. Table 23
presents the annual costs for each model combustor. A copy of
the algorithm showing the calculations and resulting equations
for the DI/FF control device is presented in Appendix D.
3.4.3.1.1 Electricity. The annual fan electricity cost is
a function of the fan hp, the unit electricity cost, and the
annual hours of operation. The fan hp values used in the
algorithm were determined by the same method used to develop the
capital costs (i.e., the hp requirements reported by the vendors
were plotted versus the gas flow rate, and the equation for the
line through the data was determined using least-squares linear
regression).32'33'35 Figure 22 summarizes the data. A unit cost
of $0.06/kWh was provided by three vendors.28'32'33 Because two
vendors indicated that other electrical components consume, on
average, 22 percent as much electricity as the I.D. fan, the fan
electricity demand was multiplied by a factor of 1.22 to estimate
the total electricity demand.46'49
3.4.3.1.2 Makeup lime. Makeup lime rates were based on a
lime-to-acid gases SR of 2.5:1 (see Section 2.2.2.5). For this
analysis, HC1 is the only acid gas evaluated because
EPA-sponsored emissions tests of an MWI with a DI/FF control
device showed no control of the low uncontrolled S02 emissions.
Dry lime costs of $100/ton and $90/ton were obtained from two
vendors.32'33 The higher unit cost was used in the algorithm.
3.4.3.1.3 Rvaorativ^ r.nnler water. The amount of water
.
added in the evaporative cooler was estimated by subtracting the
amount of moisture in the gas stream entering the control device
from that in the gas entering the FF. The inlet gas stream flow
rates that were provided to the vendors in information requests
were assumed to be 10 percent moisture. According to the vendors
81
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that use evaporative coolers, the average'moisture content of the
gas entering the FF was 38 percent, and the average temperature
was 300°F.33"35 The gas flow rates reported by all of the
vendors were used to estimate the average gas flow rate in the FF
by the same procedure described above to estimate the fan hp.
Figure 23 summarizes the reported gas flow rates and presents the
least-squares linear regression line through the averages. Based
on a January 1989 estimate from the American Water Works
Association, water was assumed to cost $0.77/1,000 gallons.
3.4.3.1.4 operating labor. Vendors estimated that
operating labor requirements would be about 1 hr/8-hr shift. A
labor wage rate of $l2/hr was used based on information from one
vendor and to be consistent with the incinerator operator wage
61
rate.
33
3.4.3.1.5 Supervisory labor. According to the QAQPS
control Cost. Manual procedures, this cost is 15 percent of the
operating labor cost. 3
3.4.3.1.6 Maintenance labor. Vendors estimated that
maintenance labor requirements would be about 0.5 hr/8-hr shift.
The wage rate was estimated to be 10 percent higher than the
operator's wage based on the OAQPS Control Cost Manual
procedures.
3.4.3.1.7 Maintenance materials. According to one DI/FF
vendor (as well as two VS/PB vendors) this cost is about
2 percent of the total capital investment. The algorithm uses
this approach rather than the o&QPS Control Cost Manual
procedure, which is to equate the materials cost with the
maintenance labor cost, because the OAQPS procedure estimates a
very low cost considering the size and cost of the control
systems.
3.4.3.1.8 ^nrnpresaed air. The amount and cost of
compressed air were both estimated based on OAQPS procedures.
These procedures specify 2 ft3 of compressed air per 1,000 ft3 of
filtered air and a cost of $0.16/1,000 ft3 of compressed air.70
The August 1986 costs were adjusted to October 1989 costs using
6771
the Chemical Engineering (CE) plant cost indexes. '
85
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3 4.3." 1.9 ""HI-, disposal. The cost of dust disposal is a
function of the amount of material captured and the unit cost for
disposal. The quantity of material captured by the FF's for each
of the model combustor gas streams was estimated based on
estimated inlet and outlet PM loadings, uncontrolled HC1
concentrations and removal efficiency, and the amount of
unreacted lime. Based on test data, the uncontrolled PM loadings
range from 0.024 to 0.16 grain (gr)/dscf at 7 percent 02,
depending on the combustor design; control device outlet levels
are 0.01 gr/dscf for all model combustors. Test data also showed
the inlet HC1 concentrations range from 120 ppm to 1,460 ppm at
7 percent O2, depending on the type of waste burned and the
combustor design.72 The HC1 removal efficiency is assumed to be
95 percent for all model combustors. Based on this removal
efficiency and an SR of 2.5:1, about 62 percent of the makeup
lime is unreacted.
The dust disposal cost was estimated assuming disposal at a
municipal waste landfill because this is the method used by most
facilities with DI/FF control devices. Typically, these
facilities mix the fly ash/lime with incinerator bottom ash,
either in a dumpster or by feeding the captured material back
into the incinerator.73'76 This mixture tests as unhazardous
waste under the Resource Conservation and Recovery Act's Toxicity
Characteristic Leaching Procedure (TCLP) test. The unit disposal
cost was assumed to be $40/ton, as noted above for bottom ash
disposal costs.
A few facilities, primarily those from one commercial
disposal firm, dispose of the fly ash/lime in a hazardous waste
landfill because lead causes the material to test as hazardous
waste under the TCLP test.37'77
3.4.3.1.10 P«q replacement. An equation to estimate the
bag replacement costs was based on the CRF; the initial bag cost,
including taxes and freight; and the bag replacement labor. The
CRF is 0.5762, assuming an annual interest rate of 10 percent and
a 2-year bag life, the average life reported by the vendors. The
initial bag costs were based on estimates of the total fabric
87
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area, the taxes and freight adjustment factor, and the unit cost
for the bag material. To estimate the total fabric area, the
equation for the average flow rate in the FF (as determined in
Section 3.4.3.1.3) was divided by the average G/C ratio (3.5:1).
Taxes and freight were assumed to be equal to 8 percent of the
bag cost. According to the vendors, the average cost for
material that can achieve an emission level of 0.015 gr/dscf at
7 percent O2 is about $2.5/ft2.32'34'35,46,49, 50, 55
Labor requirements were based on the number of bags, the
time to replace each bag, and the wage rate. The number of bags
was estimated by dividing the total FF area by the average bag
area--18 ft2 according to the vendors—and the G/C ratio.
According to OAQPS procedures, the time to replace each bag is
about 0.15 hr.63 The labor wage rate was assumed to be the same
as the operator wage rate ($l2/hr).
3.4.3.1.11 Cage replacement. An equation to estimate the
cage replacement costs was developed from the number of cages,
the individual cage cost, the replacement labor requirements, and
the CRF. The number of cages is equivalent to the number of bags
estimated above. Individual cage costs in August 1986 dollars
were estimated based on OAQPS procedures, except that the cost
for 100 count lots was used for all systems.63 This was done to
simplify the analysis and because it has only a very small impact
on the cost. The individual cage costs were adjusted to October
1989 costs using the CE plant cost indexes.67'71 Because it was
assumed that the time to replace the cages is equivalent to the
time to replace the bags, the replacement labor costs are
equivalent. The CRF is 0.3156, assuming an interest rate of
10 percent and a replacement frequency of 4 years. It was
assumed that the cages would be replaced every 4 years because
one vendor estimated that cages would need to be replaced (due to
corrosion) every other time the bags are replaced.75
3.4.3.1.12 Overhead. According to the OAOPS Control CQJ?J-
MfrPWil/ overhead is estimated as 60 percent of the operating,
supervisory, and maintenance, labor and the maintenance
materials.69
88
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Electricity costs were estimated by assuming all of the
motors were running continuously during all operating hours
(including 2 hr of cooldown for intermittent units and 10 hr of
cooldown for batch units). This assumption overestimates the
cost because the feed and ash rams do not operate continuously.
Electricity costs were assumed to be $0.06 per kilowatt-hour
(Kwh).28,32,33
3.3.2 Auxiliary Fuel
Auxiliary fuel costs are based on the type of fuel, the
burner capacities, and the burner utilization rates. Natural gas
was specified as the auxiliary fuel for all of the models because
it is used in nearly all existing MWI'a.7'12'13'22 Natural gas
costs were assumed to be $0.35/therm, which is
$3.5/1,000,000 Btu.25
Burner capacities for all combustor designs were obtained
from one manufacturer each. The equation for the best-fit line
through each data set as determined by least-squares linear
regression was used to estimate burner capacities for the model
combustors.
During the preheat phase, the secondary chamber burner is on
continuously in all combustors. Because of its lower setpoint
temperature, the primary chamber preheat for intermittent,
continuous, and pathological combustors may be completed before
the secondary chamber preheat. If so, the primary chamber burner
will cycle on and off to maintain the setpoint temperature until
the first charge is introduced. The primary chamber is not
preheated in batch combustors.
After the first few charges during the burning phase, the
primary chamber burner is typically off in intermittent and
continuous combustors, as long as waste is charged regularly
(although it can be significantly below the design rate). For
batch combustors, the primary chamber burner fires for a preset
time period (about 60 seconds) to ignite the waste; it then turns
off. in pathological incinerators, the primary chamber burner
cycles on and off as necessary. During the burning phase, the
secondary chamber burners in all combustors cycle on and off or
57
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between high- fire and low- fire as necessary to maintain the
setpoint temperature.
During burndown, burners in the primary chamber of
intermittent, continuous, and pathological combustors may also
cycle on and off or between high- fire and low- fire as needed to
maintain setpoint temperatures. In batch combustors, the primary
chamber burner remains off. The secondary chamber burner cycles
in all combustors .
Fuel consumption rates during preheat were estimated by
assuming the secondary chamber burners for all combustor types
are on 100 percent of the time; the primary chamber burner was
also assumed to be on 100 percent of the time, except in batch
units, where it is off. During the burning phase (or the "low-
air" phase for batch units) , the secondary chamber burner was
assumed to be on 50 percent of the time in all combustor types;
the primary chamber burner was assumed to be on 50 percent of the
time in pathological units, and it was assumed to be off in the
others. During burndown (or the high-air" phase for batch
models) , the primary chamber burner was assumed to be on
75 percent of the time in all except batch units, where it is
off. The secondary chamber burner was assumed to be on
90 percent of the time during burndown in all combustors.
3.3.3 Water
Three manufacturers indicated the water injection rates for
cooling the primary chamber in intermittent and continuous
combustors. The highest of, the three flow rates was used in the
analysis. Even so, the annual water cost is minor. Water costs
were estimated to be $0.77/1,000 gallons. 61
3.3.4 Operatin
Based on observation of operators at several facilities, it
was estimated that, for all combustor types except batch units,
operators spend about 50 percent of their time tending to the
incinerator during the burning phase. For the batch model, it
was assumed that operators spend about 1 hour to start the unit ,
add the waste, and monitor the process. For both intermittent
and batch combustors, an additional 0.25 to l hour was allocated
58
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for ash removal, depending on the combustor size. Operator wage
rates were assumed to be $12/hr--the same as the rate for MWC
CO
operators. •*
3.3.5 Supervisory Labor
According to the QAOPS Control Cost Manual, the cost for
supervisory labor is about 15 percent of the operating labor
cost.63
3.3.6 Maintenance Labor
According to the OAQPS Control Cost Manual, maintenance
labor requirements for air pollution control incinerators are
about 0.5 hr/8-hr shift, and the"wage rate is 10 percent higher
than the operator wage rate.64 The maintenance labor
requirements were assumed to be the same for MWI's.
3.3.7 Maintenance Materials
Annual maintenance materials costs are assumed to be equal
to 2 percent of the TCI.
3.3.8 Ash Disposal
Based on information from EPA-sponsored emissions tests, the
weight of the ash that is removed from the combustor is 9 percent
of the waste charged.15'17 The costs to dispose of ash in a
municipal waste landfill were estimated to be $40/ton in
October 1989 dollars. This cost is based on an estimated cost in
June 1991 of $43/ton and an assumed inflation rate of 5 percent
per year.65
3.3.9 Refractory Replacement
Equations to estimate the annual costs for replacing the
primary and secondary chamber refractory were developed from the
installed refractory cost and the capital recovery factor (CRF).
The installed refractory costs are a function of the volume and
configuration of the chambers, the thickness of the refractory,
and the unit cost to purchase and install 1 cubic foot (ft3)
material. Each of these parameters is discussed below.
Typically, the walls of the primary and secondary chambers
are lined with either high-strength, castable refractory or high-
heat-duty firebrick. Most manufacturers also add an insulating
mineral wool block and/or ceramic fiber mat on top of the
59
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refractory; one manufacturer, however, circulates air between the
primary chamber refractory, which is attached to an inner shell,
and the outer shell. The refractory thickness in both chambers
ranges from 3 to 6 in., depending on the manufacturer and the
capacity of the combustor. Insulation thickness ranges from 1.5
to 3.0 in. For this analysis, it was assumed that the refractory
and insulation thicknesses in both chambers are 4.5 and 2.0 in.,
respectively, for all models.
Primary and secondary chamber volumes are based on
information from manufacturers, other model combustor parameters,
and assumptions. The model primary chamber volumes are based on
information from manufacturers of batch, intermittent, and
continuous combustors. This information is shown, along with the
equations that were determined by linear regression, in
Figures 15 through 17. It was assumed that primary chamber
volumes for pathological model combustors are similar to those
for intermittent combustors because dual-purpose units are more
common than hot-hearth designs. Secondary chamber volumes for
all model combustors are based on the gas stream flow rate and
the 1-second residence time.
The interior dimensions of the primary and secondary
chambers are based on information from one manufacturer,
observations of existing units, and assumptions. Typically, both
chambers are enclosed in cylindrical shells. According to one
manufacturer, the internal length-to-diameter (L/D) ratio is
about 1.5 for horizontal primary chambers.66 Based on
observations of vertical primary chambers, the height is about
1.5 times the diameter. It was assumed that the L/D ratio is 2:1
for all secondary chambers. Although designs are unique to each
manufacturer, the refractory volumes for both chambers in all of
the model combustors were estimated based on the chamber volumes
and this dimensional information.
Unit costs for refractory and insulation (material plus
installation costs) were obtained from the OAOPS Control Coat
Manual and updated from December 1977 to October 1989 costs using
the CE plant cost indexes.67'68 The resulting costs are $l27/ft3
60
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and $43/ft^ for refractory and insulation, respectively.
According to manufacturers, the average refractory life is about
8 years (although they indicated a range from 2 to 15+ years).
The CRF based on this life and an interest rate of 10 percent is
0.18744.
3.3.10 Overhead
According to the OAOPS Control Cost Manual, overhead costs
are about 60 percent of all labor and maintenance material
costs.^
3.3.11 Property Tax. Insurance, and Administration
According to the OAOPS Control Cost Manual, annual costs for
these items amount to about 4 percent of the total capital
investment.^
3.3.12 Capital Recovery
According to MWT manufacturers, the combustor life
expectancy is about 20 years. The CRF, 0.11746, was based on the
life expectancy and an interest rate of 10 percent. This factor
was multiplied by the TCI, minus the initial refractory cost, to
estimate the capital recovery.
3.4 CONTROL TECHNOLOGY ANNUAL COSTS
This section presents annual costs for the same combustion
and APCD control technologies for which capital costs were
estimated in Section 3.2. Annual costs for FF-based control
devices with activated carbon injection are presented in
Section 3.5.
As indicated above, combustion controls are based on a
larger secondary chamber with a gas residence time of 2 seconds
and an operating temperature of 1800°F. Increasing the
temperature increases the flow rate through the APCD because more
water would need to be evaporated to cool the gas stream. The
flow would also increase because additional combustion air is
added with the additional natural gas. However, the impact on
the flow rate is small (about 5 percent), and it was assumed that
the same size APCD equipment could be used for an MWI with or
without combustion controls.
64
-------
and
3.4.1 Combustion Control Annual Costs
The additional capital cost for the larger secondary chamber
results in additional maintenance, overhead, property tax,
insurance, administration, and capital recovery costs. These
costs were calculated by the same procedures described in
Section 3.3. Refractory replacement costs are also higher,
they were calculated by the same procedure described in
Section 3.3.9, except with twice the chamber volume.
Annual fuel costs were estimated for two additional
auxiliary fuel requirements. First, additional fuel is required
to maintain 1800°F rather than 1700°F in the secondary chamber.
Second, additional fuel is needed to maintain the temperature at
1800°F for an average of 2 hours during cooldown in intermittent
models and for 10 hours in batch models.
The resulting combustion control annual costs for each of
the model combustors are presented in Table 15. A copy of the
.combustion control cost algorithm is presented in Appendix B.
3.4.2 Wet Control Device Annual Costs
Direct and indirect annual costs were estimated for wet
control devices as applied to all of the model combustors.
Direct annual operating costs were estimated for electricity for
the fan and scrubber water pump (the items that consume nearly
all of the electricity required by the system, according to two
vendors), makeup scrubber water, operating and supervisory labor,
maintenance labor and materials, caustic, and sewage disposal.
Indirect annual costs were estimated for overhead, property tax,
insurance, administrative charges, and capital recovery.
The equations used to estimate many of the annual costs are
functions of the gas flow rate into the control system. In
addition, each of the direct costs and the overhead cost are
functions of the annual hours of operation. The annual costs for
all control devices are based on the operating hours for each
model combustor as described in Tables 6 through 8. The basis
for each cost is described below. The operating parameters for
the VS/PB control device were used as the starting point for VS
and PB control device operating parameters and annual costs. The
65
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The CRF is 0.1 1746, base
66
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formulas developed to calculate the annual costs for each wet
control device are shown in Tables 16 to 18. Tables 19 through
21 present the APCD annual costs for each wet control device as
applied to each model combustor. A copy of the algorithm showing
the calculations and resulting equations for the VS/PB control
device is presented in Appendix C.
3.4.2.1 Venturi Scrubber /Packed Bed. As indicated in
Table 9, the typical pressure drop is 30 in. w.c. through the
venturi throat and 4 in. w.c. through the PB. It was assumed
that the pressure drop through the rest of the system is 4 in.
w.c.
3.4.2.1.1 Fan electricity. The annual electricity cost for
the fan is a function of the fan hp and the unit electricity
cost. The fan hp values used in the algorithm were determined by
the same method used to. develop the capital costs (i.e., the hp
requirements reported by the vendors were plotted versus the gas
flow rate in dscfm, and the equation for the line through the
28 29 31 45
averages was determined using linear regression) .
Figure 18 presents the reported data and the line determined by
linear regression. A unit cost of $0.06/kWh was provided by
three vendors.28'32'33
3.4.2.1.2 Pump electricity. The annual electricity cost
for the scrubber water pump was estimated by the same procedure
as that described above for the fan electricity. Figure 19
presents the pump hp values reported by one vendor versus the gas
flow rate.28 Also shown is the equation developed by linear
regression for the line through the data. The vendors use from
one to three pumps to circulate liquid. The algorithm is based
on only one pump because the highest horsepower ratings were
reported by the vendor that uses only one pump.
3.4.2.1.3 Scrubber makeup water . The makeup water costs
are a function of the makeup flow rates and the unit cost for
water. The makeup water requirements were estimated by the same
procedure as that described above for the electricity
requirements. Figure 20 presents the reported makeup rates
versus the gas flow rates in dscfm and the line determined by
67
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least-squares linear regression through the averages of the
reported values. The reported makeup rates were based on the
amount of water needed to replenish losses due to evaporation in
the quench and to replace blowdown losses. The evaporation rates
are for cooling the exhaust gas (10 percent moisture and 1800°F)
to saturation. Blowdown rates are presented in
Section 3.4.2.1.9. Based on a 1989 estimate from the American
Water Works Association, water was assumed to cost
$0.77/1,000 gal.61
3.4.2.1.4 Operating labor. Vendors estimated that average
operating labor rates are about 0.4 hr/8-hr shift. A labor wage
rate of $12/hr was used to be consistent with the rate for
incinerator operators.
3.4.2.1.5 Supervisory labor. According to the OAQPS
Control Cost Manual procedures, the supervisory labor is
estimated as 15 percent of the operating labor.63
3.4.2.1.6 Maintenance labor. Vendors estimated that
maintenance labor requirements would be about 0.3 hr/8-hr shift.
The wage rate was assumed to be 10 percent higher than the
operating labor wage rate based on the QAQPS Control Cost Manual
procedures.64
3.4.2.1.7 Maintenance materials. The annual maintenance
materials costs were estimated by two vendors to be about
2 percent of the TCI.28'29 The algorithm uses this approach
rather than the OAQPS procedure, which is to equate the materials
cost with the maintenance labor cost, because the OAQPS procedure.
estimates a very low cost considering the size and cost of the
control systems.
3.4.2.1.8 Caustic. The sodium hydroxide (NaOH) costs are a
function of the exhaust gas flow rate, the uncontrolled
concentrations of acid gases, the NaOH-to-acid gases molar ratio,
and the dry NaOH unit cost. Hydrogen chloride is the only acid
gas evaluated in this analysis because EPA-sponsored emissions
test of MWI's showed VS/PB devices did not reduce the low
concentrations of S02. Uncontrolled HC1 concentrations range
from 120 ppm at 7 percent 02 to 1,460 ppm at 7 percent O2,
77
-------
depending on the type of waste burned and the combustor design.
As indicated in Section 2.2, only enough NaOH is added to keep
the pH at or just below 7.0. Therefore, the NaOH-to-HCl molar
ratio is essentially 1:1. Caustic costs of $400/ton and $375/ton
were provided by two vendors.28'29 The higher unit cost was used
in the algorithm.
3.4.2.1.9 Sewage disposal. The sewage disposal costs are a
function of the blowdown rate and the unit cost for disposal.
The blowdown rates used in the algorithm were developed by the
same procedure used to estimate fan hp requirements. Figure 21
presents the reported data as well as the line determined by
least-squares linear regression through the average of the
reported values. Vendors estimated blowdown rates based on the
acid gases concentrations that were provided in the EPA
information requests (1,200 ppm HC1 and 60 ppm S02 at 7 percent
02) and on their guaranteed removal efficiencies. Differences iii
blowdown rates that may result from different uncontrolled acid
gases concentrations or removal efficiencies were neglected in
this analysis because they have only a small impact on the cost.
One vendor estimated that sewage disposal costs are about
$2/1,000 gal.28
3.4.2.1.10 Overhead.' According to OAQPS procedures,
overhead is estimated as 60 percent of the operating,
supervisory, and maintenance labor and the maintenance
materials.69
3.4.2.1.11 Property tax, insurance, and administrative.
According to OAQPS procedures, these costs are estimated as
4 percent of the TCI.69
3.4.2.l.12 Capital recovery. According to the vendors, the
equipment life expectancy is between 15 and 20 years. The CRF,
0.11746, was based on a 20-year life expectancy and an interest
rate of 10 percent. This factor was multiplied by the TCI to
estimate the capital recovery.
3.4.2.2 Venturi Scrubber. The fan hp requirements and
electricity costs are 10 percent lower for this control device
than for the VS/PB control device described above
78
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(Section 3.4.2.1) because removal of the absorber reduces the
system pressure drop by about 10 percent. The pump hp and
electricity cost are 55 percent lower because three vendors
indicated that about 55 percent of the total liquid flow is to
the absorber in VS/PB control devices.28'29'31 Maintenance
materials and indirect costs are lower than those for the VS/PB
control device because the capital costs are lower. Other annual
costs are the same as those for the VS/PB control device. The
annual cost equations are presented in Table 17, and the costs as
applied to the model combustors are shown in Table 20.
3-4.2.3 Packed Bed. Removing the VS from the VS/PB control
device reduces the system pressure drop and, thus, the fan hp and
electricity cost by about 80 percent. The pump hp and
electricity cost for this control device are 30 percent lower
than those for the VS/PB device. This reduction is based on
information from two vendors that 30 percent of the liquid flow "
in the VS/PB control device, is to the venturi.29'31 Maintenance
materials and indirect costs are lower because the capital cost
is lower than that for the VS/PB control device. Other annual
cost components are the same as those for the VS/PB device. The
annual cost equations are shown in Table 18, and the costs as
applied to the model combustors are shown in Table 21.
3.4.3 Annual Costs for Control Devices with an FF
Direct and indirect annual costs were estimated for DI/FF,
FF, FF/PB and SD/FF control devices for all of the model
combustors. It was assumed that the DI/FF and FF control devices
have an evaporative cooler to reduce the cornbustor exhaust gas to
300°F; the spray dryer also reduces the gas temperature to 300°F.
It was also assumed that all four control devices have an FF with
a G/C ratio of 3.5.
3.4.3.1 Dry Iniection/Fabric Filter. Direct annual costs
were estimated for electricity, makeup lime, evaporative cooler
water, operating and supervisory labor, maintenance labor and
materials, compressed air for the FF, dust disposal, bag
replacement, and cage replacement. Indirect annual costs were
estimated for overhead, property tax, insurance, administrative
80
-------
charges, and capital recovery. Information about many of the
operating parameters was obtained from vendors; other parameters
were estimated. The basis for each cost is described in the
subsections below. The formulas developed to calculate the
annual costs are shown in Table 22. Most of the equations are a
function of the gas flow rate into the control device and many
are also related to the annual hours of operation. Table 23
presents the annual costs for each model combustor. A copy of
the algorithm showing the calculations and resulting equations
for the DI/FF control device is presented in Appendix D.
3>4.3.1.1 Electricity. The annual fan electricity cost is
a function of the fan hp, the unit electricity cost, and the
annual hours of operation. The fan hp values used in the
algorithm were determined by the same method used to develop the
capital costs (i.e., the hp requirements reported by the vendors
were plotted versus the gas flow rate, and the equation for the
line through the data was determined using least-squares linear
regression).32'33'35 Figure 22 summarizes the data. A unit cost
of $0.06/kWh was provided by three vendors.28'32'33 Because two
vendors indicated that other electrical components consume, on
average, 22 percent as much electricity as the I.D. fan, the fan
electricity demand was multiplied by a factor of 1.22 to estimate
46 49
the total electricity demand. '
3.4.3.1.2 Makeup lime. Makeup lime rates were based on a
lime-to-acid gases SR of 2.5:1 (see Section 2.2.2.5). For this
analysis, HC1 is the only acid gas evaluated because
EPA-sponsored emissions tests of an MWI with a DI/FF control
device showed no control of the low uncontrolled S02 emissions.
Dry lime costs of $100/ton and $90/ton were obtained from two
vendors.32'33 The higher unit cost was used in the algorithm.
3.4.3.1.3 Kvaporativ^ r.ooler water. The amount of water
added in the evaporative cooler was estimated by subtracting the
amount of moisture in the gas stream entering the control device
from that in the gas entering the FF. The inlet gas stream flow
rates that were provided to the vendors in information requests
were assumed to be 10 percent moisture. According to the vendors
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that use evaporative coolers, the average moisture content of the
gas entering the FF was 38 percent, and the average temperature
was 300°F.33"35 The gas flow rates reported by all of the
vendors were used to estimate the average gas flow rate in the FF
by the same procedure described above to estimate the fan hp.
Figure 23 summarizes the reported gas flow rates and presents the
least-squares linear regression line through the averages. Based
on a January 1989 estimate from the American Water Works
Association, water was assumed to cost $0.77/1,000 gallons.61
3.4.3.1.4 Operating labor. Vendors estimated that
operating labor requirements would be about 1 hr/8-hr shift. A
labor wage rate of $12/hr was used based on information from one
vendor and to be consistent with the incinerator operator wage
rate.33
3.4.3.1.5 Supervisory labor. According to the QAQJPS
control Cost Manual procedures, this cost is 15 percent of the
operating labor cost.63
3.4.3.1.6 Maintenance labor. Vendors.estimated that
maintenance labor requirements would be about 0.5 hr/8-hr shift.
The wage rate was estimated to be 10 percent higher than the
operator's wage based on the OAQPS Control Cost Manual
procedures.64
3.4.3.1.7 MaintenanrP materials. According to one DI/FF
vendor (as well as two VS/PB vendors) this cost is about
2 percent of the total capital investment. The algorithm uses
this approach rather than the OAQPS Control Cost Manual
procedure, which is to equate the materials cost with the
maintenance labor cost, because the OAQPS procedure estimates a
very low cost considering the size and cost of the control
systems.
3.4.3.1.8 rnrnpresaed air. The amount and cost of
compressed air were both estimated based on OAQPS procedures.
These procedures specify 2 ft3 of compressed air per 1,000 ft of
filtered air and a cost of $0.16/1,000 ft3 of compressed air.70
The August 1986 costs were adjusted to October 1989 costs using
the chemical Engineering (CE) plant cost indexes.67'71
85
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3.4.3.1.9 Dust disposal. The cost of dust disposal is a
function of the amount of material captured and the unit cost for
disposal. The quantity of material captured by the FF's for each
of the model combustor gas streams was estimated based on
estimated inlet and outlet PM loadings, uncontrolled HC1
concentrations and removal efficiency, and the amount of
unreacted lime. Based on test data, the uncontrolled PM loadings
range from 0.024 to 0.16 grain (gr)/dscf at 7 percent 02,
depending on the combustor design; control device outlet levels
are 0.01 gr/dscf for all model combustors. Test data also showed
the inlet HC1 concentrations range from 120 ppm to 1,460 ppm at
7 percent 02, depending on the type of waste burned and the
combustor design.72 The HC1 removal efficiency is assumed to be
95 percent for all model combustors. Based on this removal
efficiency and an SR of 2.5:1, about 62 percent of the makeup
lime is unreacted.
The dust disposal cost was estimated assuming disposal at a
municipal waste landfill because this is the method used by most
facilities with DI/FF control devices. Typically, these
facilities mix the fly ash/lime with incinerator bottom ash,
either in a dumpster or by feeding the captured material back
into the incinerator.73-76 This mixture tests as nonhazardous
waste under the Resource Conservation and Recovery Act's Toxicity
Characteristic Leaching Procedure (TCLP) test. The unit disposal
cost was assumed to be $40/ton, as noted above for bottom ash
disposal costs.
A few facilities, primarily those from one commercial
disposal firm, - dispose of the fly ash/lime in a hazardous waste
landfill because lead causes the material to test as hazardous
waste under the TCLP test.37'77
3.4.3.1.10 Bag replacement. An equation to estimate the
bag replacement costs was based on the CRF; the initial bag cost,
including taxes and freight; and the bag replacement labor. The
CRF is 0.5762, assuming an annual interest rate of 10 percent and
a 2-year bag life, the average life reported by the vendors. The
initial bag costs were based on estimates of the total fabric
87
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area, the taxes and freight adjustment factor, and the unit cost
for the bag material. To estimate the total fabric area, the
equation for the average flow rate in the FF (as determined in
Section 3.4.3.1.3) was divided by the average G/C ratio (3.5:1).
Taxes and freight were assumed to be equal to 8 percent of the
bag cost. According to the vendors, the average cost for
material that can achieve an emission level of 0.015 gr/dscf at
7 percent 02 is about $2.5/ft2,32/34/35,46,49,50,55
Labor requirements were based on the number of bags, the
time to replace each bag, and the wage rate. The number of bags
was estimated by dividing the total FF area by the average bag
area--18 ft2 according to the vendors--and the G/C ratio.
According to OAQPS procedures, the time to replace each bag is
about 0.15 hr.63 The labor wage rate was assumed to be the same
as the operator wage rate ($12/hr).
3.4.3.1.11 Cage replacement. An equation to estimate the
cage replacement costs was developed from the number of cages,
the individual cage cost, the replacement labor requirements, and
the CRF. The number of cages is equivalent to the number of bags
estimated above. Individual cage costs in August 1986 dollars
were estimated based on OAQPS procedures, except that the cost
for 100 count lots was used for all systems.63 This was done to
simplify the analysis and because it has only a very small impact
on the cost. The individual cage costs were adjusted to October
1989 costs using the CE plant cost indexes.67'71 Because it was
assumed that the time to replace the cages is equivalent to the
time to replace the bags, the replacement labor costs are
equivalent. The CRF is 0.3156, assuming an interest rate of
10 percent and a replacement frequency of 4 years. It was
assumed that the cages would be replaced every 4 years because
one vendor estimated that cages would need to be replaced (due to
corrosion) every other time the bags are replaced.75
3.4.3.1.12 Overhead. According to the OAOPS Control Coat
Pfenyal, overhead is estimated as 60 percent of the operating,
supervisory, and maintenance labor and the maintenance
materials.69
88
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3.4.3.1.13 Property tax, insurance, and administrative.
These costs were estimated as 4 percent of the TCI based on the
OAQPS Control Cost procedures.^
3.4.3.1.14 Capital recovery. According to four vendors,
the equipment life expectancy is 15 to 20+ years.32"34'46 The
CRF, 0.11746, was based on a 20-yr life expectancy and an
interest rate of 10 percent. This factor was multiplied by the
TCI, minus the initial bag and cage costs, to estimate the
capital recovery.
3.4.3.2 Fabric Filter. The costs for the DI/FF control
device were used as the starting point for estimating the FF
costs. Eliminating the dry injection equipment eliminates makeup
lime costs. It also reduces dust disposal costs significantly
because lime and reaction products are the major components of
the FF dust in DI/FF control devices. No data are available to
indicate how much of the non-I.D. fan electricity requirements
are consumed by the dry injection feed equipment and controls.
Therefore, it was assumed that the non-I.D. fan electricity
requirements for the FF device would be 50 percent lower than
these for the DI/FF device. Maintenance materials and all
indirect costs are also lower because the TCI for this control
device is lower. All other annual cost components are the same
as for DI/FF control devices that are designed for the same gas
flow rates. The equations for estimating the costs are shown in
Table 24, and the costs are shown in Table 25.
3.4.3.3 Fabric Filter/Packed Bed. Annual costs for this
control device were estimated by combining costs for various wet
control devices with those for the FF device. The resulting
equations that were used to estimate the annual costs are shown
in Table 26, and the annual costs as applied to each model
combustor are shown in Table 27. Assuming the pressure drop
through the control device is about 19 in. w.c. (5 in. for FF,
5 in. through the heat exchanger both times, 4 in. for PB), the
fan hp and electricity costs are about 50 percent of those for
the VS/PB control device. The water recirculation and pump
electricity costs are assumed to be the same as for the PB
89
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control device. The makeup water requirements are assumed to be
the same as those for a VS/PB control device that uses a heat
exchanger (e.g., a WHRB) to cool the gases from the MWI. One
vendor indicated that the makeup water rate for such a system is
67 percent lower than that for a control device with an
evaporative quench.^° This difference in flow rate translates
into an equivalent reduction in annual costs. Operating and
maintenance labor requirements are estimated to be 1 hr/8-hr
shift and 0.5 hr/8-hr shift, respectively. Caustic requirements
and sewer charges are the same as those for the VS/PB control
device. Compressed air, bag replacement, and cage replacement
costs are slightly lower than those for the other FF-based
control devices because a heat exchanger rather than evaporative
cooling is used to reduce the gas temperature to 300°F;
consequently, the gas flow rate is also lower and the size of the
FF is smaller. Dust disposal costs are the same as for the FF
control device.
3.4.3.4 Spray Dryer/Fabric Filter. The equations for
estimating the annual costs are, shown in Table 28, and the costs
are shown in Table 29. Electricity, spray dryer water, makeup
lime, labor, dust disposal and cage replacement, and compressed
air costs are assumed to be the same as those for the DI/FF
control device. Maintenance materials costs are higher because
the SD/FF system is more complex than the DI/FF equipment.
Consequently, overhead costs are also slightly higher for the
SD/FF control device. Property tax, insurance, administrative
and capital recovery costs are higher for the SD/FF control
device because they are based on the total capital investment,
which is higher for the SD/FF.
3.5 ACTIVATED CARBON INJECTION COSTS
This section presents capital and annual costs for the
activated carbon injection system.
3.5.1 Total Capital Investment for Activated Carbon Injection
Equipment
As discussed in Section 2.2, data from EPA-sponsored
emissions tests indicate that injecting activated carbon before
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the fabric filter in DI/FF and SD/FF systems improves the removal
efficiency of both CDD/CDF and Hg. The TCI for activated carbon
injection was estimated for MWI's with DI/FF or an FF/PB by
scaling the cost for equipment used to inject activated carbon
into one DI/FF system. The facility using this equipment has a
680 Ib/hr intermittent MWI and the equipment cost was estimated
to be $4,500.78 The "six-tenths" costing rule was used to scale
the cost. Exhaust gas flow rates were used to scale the cost.
Exhaust gas flow rates were used as the capacity parameter in the
procedure. The resulting equation is shown in Table 30.
The equipment required for the activated carbon injection
process consists of a storage bin and a feeder mechanism to
inject the carbon into the ductwork of a DI/FF or FF/PB control
system. No capital costs are necessary for MWI's with an SD/FF
control system since the activated carbon can be mixed with the
lime slurry.
3.5.2 Annual Costs for Activated Carbon Injection
Direct and indirect annual costs were estimated for
activated carbon injection for DI/FF and FF/PB control devices
and for SD/FF control devices for all of the model combustors.
Direct annual costs were estimated for operating and supervisory
labor, maintenance, activated carbon, and dust disposal.
Indirect annual costs were estimated for overhead, property tax,
insurance, administrative charges, and capital recovery. The
basis for each cost is described in the subsections below.
The formulas developed to calculate the annual costs are
shown in Table 30. Most of the equations are a function of the
gas flow rate into the control device, and many are also related
to the annual hours of operation. Table 31 presents the annual
costs for activated carbon injection for DI/FF and FF/PB control
devices for each model combustor. Table 32 presents the annual
costs for activated carbon injection for SD/FF control devices
-for each model combustor.
3.5.2.1 Operating Labor. Operating labor requirements to
load the activated carbon into the storage bin and to perform
other daily system checks are expected to be small. For this
97
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TABLE 30. EQUATIONS TO ESTIMATE CAPITAL AND ANNUAL COSTS FOR
ACTIVATED CARBON INJECTION ___
A. Total capital investment, $a
B. Direct annual costs, $/yr
1. Operating labor"
2. Supervisory labor
3. Maintenance0
4. Activated carbon
a. For DI/FF and FF/PB devices'1
b. For SD/FF devices6
5. Dust disposal
a. For DI/FF and FF/PB devices
b. For SD/FF devices
C. Indirect annual costs, $/yr
1. Overhead
2. Property taxes, insurance, and
administration
3. Capital recovery^
= 4,500 (Q/1,976)0-6
= (0.25 hr/8 hr shift) x ($12/hr) x (H)
= 0.15 x (operating labor)
= 0.04 x TCI
= (1.27 x 10'3) x ($0.75/lb) x (Q) x (H)
= (7.05 x 10-4) x ($0.75/lb) x (Q) x (H)
= (1.27 x ID'3) x (Q) x (H) x ($40/ton) x (1 ton/2,000 Ib)
= (7.05 x ID"4) x (Q) x (H) x ($40/ton) x (1 ton/2,000 Ib)
= (0.6) x (all labor maintenance materials costs)
= (0.04) x (TCI)
= (0.11746) x (TCI)
aThe variable Q is the exhaust gas flow rate in dscftn.
^The variable H is the operating hours hi hr/yr.
cMaintenance cost includes maintenance labor and maintenance materials cost.
dThe factor is based on injecting carbon at a rate to achieve a carbon concentration of 338 mg/dscm.
eThe factor is based on injecting carbon at a rate to achieve a carbon concentration of 188 mg/dscm.
fThe capital recovery factor is 0.11746, based on equipment life of 20 years and an interest rate of 10
percent.
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analysis, they were estimated to be 0.25 hr/8-hr shift. The
labor wage rate was estimated to be $12/hr to be consistent with
incinerator operator wage rates.
3.5.2.2 Supervisory Labor. According the OAOPS Control
Cost Manual procedures, this cost is 15 percent of the operating
labor cost.63
3.5.2.3 Maintenance. The cost of maintenance labor and
materials was assumed to be 4 percent of the TCI. Since no
capital investment is necessary for carbon injection systems for
SD/FF control devices, there is no maintenance cost for MWI's
using those systems.
3.5.2.4 Activated Carbon. The activated carbon
requirements for MWI's with DI/FF and FF/PB control devices were
estimated using the carbon injection concentration of 338 mg/dscm
from the emissions test at Facility A and a unit cost of $0.75/lb
.of activated carbon. The activated carbon requirements for MWI's
with SD/FF control devices were estimated using the carbon
injection concentration of 188 mg/dscm from the emissions test at
Facility M and the same unit cost of activated carbon. The
activated carbon unit cost was the average of the costs for four
different carbons.79
3.5.2.5 Dust Disposal. The cost of dust disposal is a
function of the concentration of activated carbon injected and
the unit cost for disposal. Since the addition of activated
carbon does not change the outlet PM emissions, all of the carbon
injected is assumed to be captured by the FF. The unit disposal
cost was assumed to be $40/ton, as noted for bottom ash and FF
dust disposal costs.
3.5.2.6 Overhead. According the OAOPS Control Cost Manual.
overhead is estimated as 60 percent of the operating and
supervisory labor and maintenance costs.69
3.5.2.7 Property Tax. Insurance, and Administrative. These
costs were estimated as 4 percent of the TCI based on the OAQPS
Control cost procedures. Since there is no capital investment
necessary for activated carbon injection systems for SD/FF
101
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control devices, there are no property tax, insurance, and
administrative costs for MWI's using those systems.
3.5.2.8 Capital Recovery. The CRF, 0.11746, was based on a
20-year life expectancy for the activated carbon injection system
(assumed to be the same as that reported by DI/FF vendors) and an
interest rate of 10 percent. This factor was multiplied by the
TCI to estimate the capital recovery. Since there is no capital
investment necessary for activated carbon injection systems for
SD/FF control devices, there is no capital recovery cost for
MWI's using those systems.
3.6 SUMMARY OF COMBUSTOR AND CONTROL TECHNOLOGY COSTS
A summary of the model combustor and control technology
capital costs are shown in Table 33. A summary of the total
annual costs for each model combustor and each model control
technology are presented in Table 34.
4.0 MODEL COMBUSTORS AND CONTROL TECHNOLOGIES FOR EXISTING
FACILITIES
This section describes the model combustors and control
technologies that represent existing MWI's. The model combustors
are described in Section 4.1; the control technologies are
described in Section 4.2.
4.1 MODEL COMBUSTORS
A total of seven model combustors were developed to
represent the population of existing MWI's. These model
combustors are the same as the seven model combustors that also
represent new MWI's in Section 2 (see Tables 6 through 8), except
that the secondary chambers are smaller for most of the models.
Most newer units (installed since 1985) have secondary chambers
with residence times of 1 second. Older units typically have
secondary chambers with gas residence times of about 1/4 second.
Sales data collected in 1990 from combustor manufacturers
show most large continuous MWI's have been installed since 1985
and, thus, are more likely to have secondary chambers with gas
residence times of 1-second. Consequently, the 1,500 Ib/hr
continuous model representing existing MWI's was developed with a
1-second residence time (i.e., the model is identical to that
102
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representing new MWI's). The other six model combustors were
developed with 1/4-second residence times because the majority of
existing MWI's represented by these models were installed before
1985 and, thus, are more likely to have secondary chambers with
1/4-second residence times.
The retort is a combustor design that comprises a
significant percentage of the existing MWT population, but it is
not used for new MWI's. In one State, 30 percent of the existing
Q (-I
MWI's are retorts. u A separate model combustor was not
developed to represent retorts because their sizes and operation
are similar to those for pathological or intermittent combustors.
Retorts were originally designed to burn primarily pathological
waste; however, some facilities have also used them to burn
general/red bag waste. In two States, retort sizes were
determined to range from 50 to 250 lb/hr.80'81 Other State
surveys did not distinguish retorts from either pathological or
intermittent MWI's.
4.2 MODEL CONTROL TECHNOLOGIES
4.2.1 Combustion Controls
Combustion controls consist of retrofitting the combustor
with a larger secondary chamber and operating it above a
specified minimum temperature. Two levels of combustion control
were evaluated. One level of combustion control is identical to
that specified in Section 2.2.1 for new MWI's; i.e., secondary
chambers that achieve a gas residence time of 2 seconds and
operate at a temperature of 1800°F (2-sec combustion control
technology).. The second level of combustion control is based on
secondary chambers that achieve a gas residence time of 1 second
and operate at a temperature of 1700°F (1-sec combustion control
technology). For both control levels, the temperature
requirements apply to the cooldown phase, as well as the burning
and burndown phases, as long as the primary combustion air blower
is operating and the primary chamber exhaust gas temperature is
above 300°F. As noted in Section 2.1.4.5 and in Tables 6 and 7,
the applicable cooldown time is an average of 2 hr for
intermittent combustors and 10 hr for batch combustors.
105
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4.2.2 APCP' Control Technologies
The APCD control technologies are the same as those
described in Section 2.2.2. The parameters characterize design
and operation of control devices that are installed after a
combustor has been retrofitted with a 2-sec secondary chamber.
Slightly smaller control devices could be installed on combustors
with smaller secondary chambers because the gas flow rate would
be lower. The difference in the flow rate is small (only a few
percent), and it is much less than the scatter in the flow rates
that were used to establish the exhaust gas flow rates for new
units. Therefore, the parameters presented in Section 2.2.2
would also adequately characterize control devices installed on
combustors with smaller (1/4-sec to 1-sec) secondary chambers.
5.0 COSTS FOR EXISTING FACILITIES
This section presents the capital and annual control costs
for model combustors that represent existing MWI's. The control
costs include costs to retrofit existing MWI's with combustion
controls and add-on controls.
5.1 COMBUSTOR CAPITAL AND ANNUAL COSTS
Total annual costs for existing 1-sec and 1/4-sec combustors
are needed to conduct impact analyses. Capital and annual costs
for both combustors are estimated in this section.
Capital costs for existing combustors were assumed to be the
same as the capital costs for new combustors (i.e., the actual
capital investment of an existing combustor in 1989 dollars was
assumed to be the same as the capital investment of a new
combustor in 1989). Therefore, the costs for existing 1-sec
combustors are the same as those for the new 1-sec combustors
that are presented in Table 11. Since 1/4-sec combustors are no
longer produced, the costs for these units were estimated by
subtracting the difference between estimated l-sec and 1/4-sec
secondary chamber costs from the 1-sec combustor costs. The
1-sec secondary chamber costs were assumed to be equal to the
incremental cost difference between 1-sec and 2-sec secondary
chambers shown in Figure 5. The 1/4-sec secondary chambers were
estimated to be equal to 1/4 of the l-sec secondary chamber
106
-------
costs. Capital costs for the 1/4-sec combustors are shown in
Table 35.
Annual costs for existing combustors were calculated by the
same procedures described in Section 3.3 and in Appendix A. For
existing 1-sec combustors, the annual costs are the same as those
for new units in Table 14. Annual costs for existing 1/4-sec
combustors are shown in Table 35. The only differences between
the costs for 1/4-sec and 1-sec combustors are the secondary
chamber refractory replacement costs and all costs that are
estimated to be equal to a percentage of the TCI (i.e.,
maintenance materials, overhead, property taxes, insurance,
administration, and capital recovery). Fuel costs are assumed to
be the same f.or both combustors, even though heat losses may be
slightly higher for the larger 1-sec secondary chambers.
5.2 CONTROL TECHNOLOGY CAPITAL COSTS
Total capital investments were developed for combustion
control and APCD control technology retrofits. Combustion
control costs are presented in Section 5.2.1, and APCD retrofit
costs are described in Section 5.2.2.
The TCI consists of purchased equipment and installation
costs. However, downtime costs associated with combustion
control retrofits were also developed and treated as capital
costs. It was assumed that downtime costs for APCD retrofits are
negligible because most of the existing MWI's are outdoors with
adequate space to install the control equipment without shutting
down the incinerator; connecting the ductwork can be performed
during a scheduled downtime for maintenance.
5.2.1 Combustion Control Total Capital Investment
A secondary chamber retrofit can be accomplished in several
ways: (1) replace the existing secondary chamber with one large
enough to achieve the necessary residence time, (2) add a
tertiary chamber to achieve the additional residence time that is
needed, or (3) expand the existing chamber by removing one end .
and making the chamber longer. The replacement option was
evaluated in this analysis; according to two manufacturers, it is
the most common way to retrofit combustors that currently have
107
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small secondary chambers (i.e., those modeled with 1/4-second
residence times).82'83
5.2.1.1 Two-Second Secondary Chamber Retrofit. Purchased
equipment costs for the 2-sec secondary chamber control
technology were estimated as double the difference between the
costs presented in Section 3 for new MWI's that, have secondary
chambers with 1- and 2-second residence times (see Figure 5).
These costs account for larger burners and blowers in the
2-second units, but they may underestimate the overall cost
slightly because the material requirements for a 2-second unit
should be less than double the material needed for a 1-second
unit.
The installation cost factor was estimated to be 0.96 times
the PEC, or twice as much as for new installations. This higher
factor accounts for demolition and removal costs and additional
field work to modify the system controls for the new burner and
blower. Thus, the TCI for 2-sec secondary chamber retrofits is
1.96 times the PEC. Table 36 presents the TCI for each of the
model combustors.
TABLE 36. TOTAL CAPITAL INVESTMENT FOR 2-SECOND SECONDARY
CHAMBER COMBUSTION CONTROL RETROFITS
Model combustor
1
2
3
4
5
6
7
Exhaust gas
flow rate, dscftn
4,747
3,165
4,747
1,899
633
455
730
Volume, ft3
753
502
753
301
100
72
116
Retrofit costs for 2-second SC
Purchased
equipment cost,
$
86,870
63,627
86,870
45,027
26,427
23,811
27,852
Installation cost,
$
83,395
61,082
83,395
43,226
25,370
22,859
26,738
Total capital
investment,
$*
170,000
125,000
170,000
83,300
51,800
46,700
54,600
aTotal capita! invstment does not include downtime cost.
Downtime costs are presented in Table 37. According to two
manufacturers, the downtime to retrofit a 2-sec secondary chamber
109
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TABLE 37. DOWNTIME COSTS ASSOCIATED WITH COMBUSTION
CONTROL DEVICES
Model
combustor
1
2
3
4
5
6
7
Waste charging rate
Ib/hr Ib/batch
1,500
1,000
1,500
600
200
500
200
Waste charging
hr/d
24
8.5
7.5
7.5
5.5
N/A
5.5
hours
d/w
6.5
6.5
6
6
6
3
6
Time to
retrofit,
days (a)
13
11
13
9
8
7
8
Downtime
days
(b)
12
6
8
4
3
3
3
Downtime
costs, $
(c)
87,000
10,251
18,090
3,618
663
302
663
(a) Downtime is based on estimates from manufacturers that retrofit work takes from 1 to 4 weeks,
depending on the size of the combustor.
(b) Downtime days are less than the number of days to retrofit by the number of days that the
incinerator is normally down for maintenance or because it is not needed. For noncommercial,
non-batch models, it is assumed that the incinerator is normally down one day per week and
that the amount of waste generated in three days can be saved and burned in addition to the
normal waste load in the days after the retrofit is completed. For batch units,
it is also assumed that the incinerator is normally down one day per week but
waste can not be saved for burning at a later date because the incinerator is normally
charged at its design rate. For commercial models, it was assumed that the incinerator
is normally down one day every other week and that waste can not be saved for burning
at a later date.
(c) Downtime costs for non-batch models are based on the following equation:
Downtime cost, $=(S0.3/lb)*(design Ib/hr * 0.67)*(hr/d)*(downtime days)
For batch models, the following equation was used:
Downtime cost, $=(S0.3/lb)* (design Ib/batch * 0.67)* (downtime days)
110
-------
would be between 1 and 4 weeks, depending on site-specific
conditions and the size of the combustor.82'83 For this
analysis, it was assumed that the downtime would be 1 week for
the smallest MWT's and 4 weeks for a large MWI (i.e., larger than
5,000 Ib/hr). Downtime for other sizes was estimated based on
the assumption that there is a linear relationship between these
two points on a plot of down time versus exhaust gas flow rate.
It was assumed that all facilities except commercial disposal
firms and those with batch combustors can save waste for up to
3 days and burn it after the retrofit work is completed. These
facilities also shut the incinerator down at least 1 day per week
for preventive maintenance or because they do not generate enough
waste on the weekends to justify operating the incinerator. For
the remaining downtime, it was assumed that these facilities
would have to contract with a commercial disposal firm' to dispose
of their waste. Average disposal costs at commercial facilities '
were estimated to be $0.30/lb.84"88
For continuous units at commercial facilities, the downtime
costs were estimated as the amount of lost revenues. The total
number of downtime days was adjusted by the assumption that
commercial incinerators are down for preventive maintenance l day
every 2 weeks.
5.2.1.2 One-Second Secondary Chamber Retrofit. The
secondary chamber volume that is needed to achieve 1-sec
residence time in one application is the same as that needed to
achieve 2-sec residence time in another application with half the
gas flow rate. For this analysis, it was assumed that the same
secondary chamber would be used in both applications and that the
retrofit costs would also be the same. The average disposal and
downtime costs may actually be slightly higher for 1-sec
retrofits because larger existing units would be replaced, but
this difference has been assumed to be small. For example, for
2-sec retrofits, a 400 ft3 secondary chamber would replace mostly
50 to 200 ft3 original units, whereas for 1-sec retrofits, it
would replace units from 100 to 400 ft3.
Ill
-------
The TCI costs presented in Table 36 for 2-sec retrofits were
used to estimate the TCI costs for 1-sec retrofits. A linear
regression analysis was performed to determine the equation of
the line through a plot of 2-sec TCI values versus the secondary
chamber volumes. The TCI values for 1-sec retrofits were then
estimated by plugging the secondary chamber volumes needed to
achieve 1-second residence times into this equation. The
resulting TCI values are presented in Table 38. There was no TCI
cost for 1-sec retrofit for model No. 1 because the baseline for
this model already includes a secondary chamber with a 1-second
residence time and an operating'temperature of 1700°F.
TABLE 38. TOTAL CAPITAL INVESTMENT FOR 1-SECOND SECONDARY
CHAMBER COMBUSTION CONTROL RETROFITS
Model
combust or
1
2
3
4
5
6
7
Exhaust
gas flow
rate, dscfm
4,747
3,165
4,747
1,899
633
455
730
Volume ,
ft3
376
251
376
151
50
36
58
Total
capital
investment, $a
0
79,100
102,000
60,900
42,700
40,100
44,100
aThere is no retrofit total capital investment for model 1
because the baseline for that model already includes a
secondary chamber that has a gas residence time of 1 second
and operates at a temperature of 1700°F.
Downtime costs were assumed to be the same as for the 2-sec
secondary chamber retrofit. This assumption may overestimate the
cost because it should be easier and less time consuming to
remove a 1/4-sec chamber and set a 1-sec unit in place than to
remove a 1-sec chamber and replace it with a 2-sec unit.
However, the time to disconnect and reconnect the fuel lines, air
112
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ducts, interlocks, thermocouples, electricity, etc., would be
about the same regardless of the secondary chamber size.
•5.2.2 APCD Total Capital Investment
On a nationwide basis, average APCD retrofit costs were
estimated to be the same as for new facilities. This estimate is
based on limited information about the population of existing
MWT's. This information shows, that most MWI's are accessible and
have room for an APCD system. Retrofit costs for these
facilities would be the same as the costs to purchase and install
APCD's at new facilities.83
5.3 CONTROL TECHNOLOGY ANNUAL COSTS
Annual costs were estimated for combustion controls and
add-on controls; the estimating procedures are described in the
following sections.
5.3.1 Combustion Control Annual Costs
Annual costs for 1-sec and 2-sec secondary chamber retrofits
are shown in Tables 39 and 40, respectively. These costs were
.estimated by the same procedures described in Section 3.4.1, with
three exceptions. First, the downtime cost is an intitial cost
that is annualized over the 20-yr life of the retrofit combustor.
Second, there is no 1-sec secondary chamber retrofit cost for
model No. 1 because this model already has a secondary chamber
that operates at 1700°F and has a gas residence time of 1 sec.
Third, the auxiliary fuel costs are lower for the 1-sec secondary
chamber retrofit because the secondary chamber operating
temperature does not have to be increased from 1700° to 1800°F.
5.3.2 APCD Annual Costs
On a nationwide basis, the average annual costs for APCD
retrofits are the same as the annual costs for new units because
it was assumed that the TCI is the same for retrofit and new
units. The costs for these models are presented in Table 34.
6.0 DISTRIBUTION OF MWI POPULATION
; In order to conduct nationwide cost, environmental, and
.energy impacts analyses, it is necessary to distribute the
projected population of new MWI's and the existing MWI population
among the final model combustors. For the economic impact
113
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analysis, the population also must be distributed among the MWI
industry segments. The distribution of new units projected to be
installed in the 5 years after proposal of the NSPS is presented
in Table 41; the distribution of existing MWI's is presented in
Tables 42 and 43.89'90 Table 42 presents the distribution of
4,850 existing MWI's at facilities in five major industries
(hospitals, commercial incineration, laboratories, nursing homes,
and veterinaries). Table 43 presents the size distribution of
150 existing MWI's in other/unidentified industries; this
distribution is assumed to be the same as that for 4,850 MWI's.
While not all new or existing MWI's exactly match the final model
combustors, the distributions presented in Tables 41 through 43
have been derived by assigning the various sizes and types of .
MWI's to the most representative model combustor.
7.0 CONTINUOUS EMISSION MONITOR COSTS
Continual compliance with emission limits can be
demonstrated by using continuous emission monitors.
Alternatively, the periodic use of portable CO monitors would
allow operators to assess the condition of the incinerator and
determine whether repairs are necessary. The use of process
monitors and periodic preventive maintenance inspections can also
help ensure that the incinerator is operating at its design
efficiency. This section presents estimated costs for each of
these monitoring and inspection activities.
7.1 CONTINUOUS EMISSION MONITORS
A computer program that was distributed by EPA's Emission
Measurement Technical Information Center (EMTIC) was used to
estimate capital costs and certain annual costs for several GEM
systems.91 Other annual costs (property taxes, insurance,
administration, and capital recovery costs) were estimated using
standard OAQPS cost factors.69 Table 44 shows the resulting TCI
and total annual costs at new facilities for opacity monitors; a
combination of CO and 02 monitors; a combination of CO, 02, and
opacity monitors; and a combination of CO, O2, opacity, and HC1
monitors. The documentation for the program also indicates that
the cost of the, HC1 monitor is variable and could be as high as
116
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TABLE 41. DISTRIBUTION OF NEW UNITS
Combustor
design
Continuous
Intermittent
Batch
Pathological
Industry
Hospital
Commercial
Lab
Hospital
Lab
Nursing
Vet
Hospital
Hospital
Lab
Nursing
Vet
Model
combustor
design
capacity8
1,000
1,500
1,000
1,500
1,000
1,500
200
600
1,500
200
600
1,500
200
600
1,500
200
600
1,500
500
200
200
200
200
Total
identified in
industry1'
62
0
0
39
4
0
513
212
50
46 '
21
~6
37
2
0
10
0
0
115
158
50
14
86
1,425
Total
identified by
design
capacity0
66
39
66
39
66
39
606
235
56
606
235
56
606
235
56
606
235
56
115
308
308
308
308
Fraction of
type in
industry
0.93939
0.00000
0.00000
1.00000
0.06061
0.00000
0.84653
0.90213
0.89286
0.07591
0.08936
0.10714
0.06106
0.00851
0.00000
0.01650
0.00000
0.00000
1.00000
0.51299
0.16234
0.04545
0.27922
Projected
No. of new
units by
design6
60
77
60
77
60
77
280
95
20
280
95
20
280
95
20
280
95
20
165
5
5
5
5
'rejected No.
of new units
in industry'
56
0
0
77
4
0
237
86
18
21
8
2
17
1
0
5
0
0
165
3
1
0
1
702
aThe design capacities are in Ib/hr for all combustors except the batch model, which is in Ib/batch.
bThe total identified in industry is the known population of MWI'a in a particular industry that is represented by each
model combustor (see Tables 2 through 5).
°The total identified by design capacity is the total known population of MWI's represented by each of the seven
model combustors (See Tables 2 through 5).
^The fraction of type in industry is the ratio of total identified in industry to total identified by design capacity.
^The projected number of new units by design capacity is the total number of new MWI's represented by each model
combustor that are projected to be installed in the 5 years after proposal of the NSPS (e.g., 280 MWI's in the
200 Ib/hr intermittent category are projected to be installed.)89
*The projected number of new units in industry is equal to the projected number of new units by design capacity times
the fraction of type in industry (e.g., 280 x 0.84653 = 237 of the 200 Ib/hr intermittent combustors are projected in
the hospital industry).
117
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TABLE 42. DISTRIBUTION OF EXISTING UNITS IN FIVE MAJOR
INDUSTRIES
Combustor
«yp*
Continuous
Intermittent
Batch
Pathological
Industry
Hospital
Commercial
Lab
Hospital
Lab
Nursing
Vet
Hospital
Hospital
Lab
Nursing
Vet
Model
combustor
design
capacity*
1,000
1,500
1,000
1,500
1,000
1,500
200
600
1,500
200
600
1,500
200
600
1,500
200
600
1,500
500
200
200
200
200
Total
identified by
design
capacity
62
0
0
• 39
4
0
5 13
212
50
46
21
-*"6
37
2
0
10
0
0
115
158
50
14
86
1,425
Total
identified in
industry0
1,110
1,110
39
39
127
127
1,110
1,110
1,110
127
127
127
53
53
53
96
96
96
1,110
1,110
127
53
96
Fraction of
type in
industry
0.05586
0.00000
0.00000
1.00000
0.03150
0.00000
0.46216
0.19099
0.04505
0.36220
0.16535
0.04724
0.69811
0.03774
0.00000
0.10417
0.00000
0.00000
0.10360
0.14234
0.39370
0.26415
0.89583
Estimated
No. of
existing
units in
industry6
3,150
3,150
150
150
500
500
3,150
3,150
3,150
500
500
500
500
500
500
550
550
550
3,150
3,150
500
500
550
Projected No.
of existing
units by
design
capacity*
176
0
0
150
16
0
1,456
602
142
181
83
24
349
19 •'
0
57
0
0
326
448
197
132
493
4,8508
*The design capacities are in Ib/hr for all combustors except the batch model, which is in Ib/batch.
bThe total identified by design capacity is known population of MWI's in the particular industry that is represented by
each model combustor (See Tables 2 through 5).
cThe total identified in industry is the sum of all known MWI's in a particular industry (e.g., 513 + 212 + 50 +
62 + 115 + 158 — 1,110 known MWI's in the hospital industry).
"The fraction of type in industry is the ratio of total identified by design capacity to the total identified in industry.
eThe estimated number of existing units in industry is the total estimated number of MWI's in a particular industry
(e.g., there are an estimated 3,150 MWI's at hospitals).90
fThe estimated number of existing units by design capacity is the estimated number of MWI's represented by each
model combustor in each industry (e.g., 3,150 x 0.46216 = 1,456 MWI's in the 200 Ib/hr intermittent category at
hospitals).
£The sum of the projected units does not equal 4,850 due to rounding.
118
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TABLE 43. DISTRIBUTION OF EXISTING MWI'S IN
MISCELLANEOUS/UNIDENTIFIED INDUSTRIES
Model
l
2
3
4
5
6
7
Total
Number of
existing MWI's
5
6
5
22
63
10
39
150
TABLE 44. CONTINUOUS EMISSION MONITOR COSTS FOR NEW MWI'S'
Parameters
Total capital investment, $
Planning
Select type of equipment
Provide support facilities
Purchased equipment cost ,
Install and check CEM'sc
Performance spec, tests (certification)
Prepare QA/QC plan
Total capital investment
Annual costs, $/yr
Operation and maintenance
Annual RATAd
Supplemental RATA
Quarterly CGA'se
Recordkeeping and reporting
Annual review and update
Property taxes, insurance, and
administrative
Capital recovery'
Total annual cost, $/yr
CEM system costs
Opacity
700
3,800
1,500
22,000
700
1,400
7,200
37,300
7,000
0
0
0
5,900
3,600"
1,500
4,400
22,400
CO and O2
3,000
10,500
9,200
68,000
12,700
15,200
12,900
131,500
10,300
10,300
9,800
3,900
12,400
17,400
5,300
15,400
84,800
CO, O2, and
opacity
3,700
13,200
10,700
90,000
13,500
16,000
17,000
164,100
17,500
10,300
9,800
3,900
18,300
20,800
6,600
19,300
106,400
CO, 02,
opacity, and
HC1
3,900
13,500
11,700
111,500
15,000
16,800
18,100
190,500
19,300
11,400
10,200
4,200
19,100
22,600
7,600
22,400
116,800
aAll costs are based on EMTIC's CEM program, except for property taxes, insurance, administrative, and
capital recovery costs, which are all based on procedures from the OAOPS Control Cost Manual.
"Includes vendor costs to install equipment and train plant technicians.
^Installation costs incurred by facility personnel.
"Relative accuracy test audit
eCylinder gas audits
The CRF is 0.11746, based on an assumed equipment life of 20 years and an interest rate of 10 percent.
119
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$150,000. The TCI for retrofits is site-specific because of
higher planning and support facility costs. According to the
program, typical retrofit costs are 10 percent higher than costs
for new facilities. However, retrofit annual costs would be only
about 2 percent higher than costs for new installations because
only the capital recovery costs are higher.
Purchased equipment, installation, and certification costs
were obtained from several GEM vendors and compared with the
results from the EMTIC program.92 This comparison is presented
in Table 45 for a system of CO, 02, and opacity monitors. The
vendor equipment costs vary over a wide range primarily because
of differences in the design, sophistication, and quality of
materials, especially for data acquisition systems (DAS's). The
average vendor installation costs.are higher than those from the
EMTIC program primarily because one vendor reported a much higher
cost than all the other vendors. The items included in the
installation costs also differ. The vendors included only costs
for contractor/vendor activities, while the program also included
the facility installation costs (e.g., the time for getting
regulatory approval, supervision of contractor/vendor
installation, start-up, calibration, and problem resolution).
Despite the variation, the overall average purchased equipment,
installation, and certification costs from the vendors differ
from the cost generated with the program by only about
10 percent.
7.2 PORTABLE CO MONITORS
Portable CO monitors would allow incinerator operators to
check the CO emissions on a periodic basis, and the cost would be
significantly less than the cost of a CO CEM. According to two
vendors, portable CO monitors cost about $1,100. Both monitors
are powered by rechargeable batteries, and the recharger is
included in the cost of the monitor. One vendor indicated that a
30-sec warm-up period is required before reliable readings are
produced. Both monitors measure CO concentrations in the range
of 0 to 2,000 ppm. The accuracy is ±2 percent of the reading for
one monitor and ±5 percent for the other monitor. For continuous
120
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TABLE 45. COMPARISON OF VENDOR AND EMTIC GEM CAPITAL COSTS
Parameters
Purchased equipment
costs, $
CO monitor
£>2 monitor
Opacity monitor
Data acquisition system
Total*3
Installation costs, $
Contractor/vendor costs
Facility personnel
costs
Certification costs, $
Total costs, $
Vendor costs
Range
6,500 to 20,600
3,600 to 16,100
14,300 to 28,700
6,000 to 42,100
66,600 to 136,500
7,400 to 60,900
10,850 to 31,200
84,850 to 228,600
Average
14,000
7,800
23,000
22,000
92,000
24,80Q
16,500
133,300
EMTIC program
costs
10,000
5,000
20,000
N/Aa
90,000
__c
13,500
16,000
119,500
computer program does not give a separate cost for data acquisition
^quipment.
~The total includes costs for sample probes, lines, conditioning system,
enclosures, etc. in addition to the monitors and the data acquisition
system.
GThe contractor/vendor costs are included in the purchased equipment
costs.
facility costs were not addressed in the vendor costs.
operation, the maximum operating temperature rating of the probes
for both monitors is 1200°F. However, one vendor indicated that
the standard probe can be replaced with an Inconel probe that can
handle temperature up to 2000°F. The other vendor indicated that
the standard probe has a short term temperature rating of 1800°F,
but replacing the probe with ceramic tubing would allow operation
at that temperature for a longer time or allow operation at
higher temperatures. One vendor indicated that the
electrochemical sensor and battery pack may need to be replaced
every 1 to 2 years at a cost of $200. Both vendors also produce
other portable monitors that can measure concentrations of
several pollutants and are designed for continuous operation at
1800° to 2200°F. These monitors cost 2 to 6 times more than the
CO monitors.93'95
121
-------
96
7.3 PROCESS MONITORS
Process parameters such as primary and secondary chamber
temperature, differential pressure across a FF, liquid flow rates
in a VS/PB device, and pressure drop across the venturi throat in
a VS/PB device can all be monitored continuously. By detecting
deviations from design specifications, these monitors could show
when corrective maintenance is needed to restore the incinerator
to good operating condition. Weighing the waste before charging
helps the operator introduce uniform charges at the design rate,
which minimizes overloading.
The cost to continuously monitor temperatures, pressures,
and flow rates will depend on the type of control device used.
Furthermore, numerous systems can be designed to monitor these
parameters. For this analysis,- costs were developed for two
systems. One system consists of a strip chart recorder and
signal wire to monitor the primary and secondary chamber
temperatures. The cost for this equipment is about $1,200.
The purchased equipment cost for a more comprehensive monitoring
system was estimated to be about $8,100. Included in this cost
is about $3,000 for a 14-channel data acquisition system that
plugs into the parallel printer port of a PC.97 The system
measures signals from thermocouples directly, and it accepts
4- to 20-milliamp signals from pressure transducers and flow
meters. A 386 computer (with monitor) that would be more than
adequate to record and process the data could be purchased for
about $3,000. Software programs to record, process, and generate
reports generally cost about $500 to $1,000. Even if a program
is not currently available to generate output in an EPA-required
format, vendors would quickly modify existing programs to make it
available. The cost of a 9-pin dot matrix printer is about $300.
Other equipment, including a pressure transducer, flow meters,
and signal wire can be purchased for less than $800.
For this analysis, it was assumed that most facilities would
choose to use a floor scale to weigh the waste--either by
weighing a cart that contains bags of waste or by manually
placing on the scale the number of bags that the hopper can hold.
122
-------
According to two scale distributors, the PEC for a 4' x 4' scale
with a digital display and one ramp would be about $3,000.98/"
7.4 MAINTENANCE SERVICE
Routine maintenance/service inspections on a periodic basis
can help keep the system operating efficiently. Information
about the cost to perform routine preventive maintenance service
was obtained from one incinerator dealer, one maintenance
contractor, and two incinerator manufacturers. Typical functions
that these contractors perform during a visit include cleaning
and adjusting burners; lubricating hinges and door latches;
inspecting/checking the controls, thermocouples, valves, door
gaskets, refractory lining, stack, and waste charging ram; and
firing the unit with typical waste to confirm that it is
operating properly. The cost for. a visit depends on the size of
the incinerator and the distance travelled. A typical visit
requires one full day and costs between $500 and $800, plus
travel, expenses, and parts.100
8.0 PERFORMANCE TESTING COSTS
This section presents estimated costs to conduct performance
testing. An EPA study estimates that the cost to conduct an
opacity test and to test for the pollutants PM, Cd, Pb, Hg,
CDD/CDF, HC1, and CO would be about $47,000.101
Typically, Method 5 is used to measure PM alone, and the
sampling and analytical cost for three runs is estimated to be
$8,000. The additional cost to conduct three Method 29 runs for
three trace metals, including Hg, is approximately $8,000. Other
strategies also can be used to measure PM and metals, and, in
each case, the cost would be about $16,000.
The estimated cost for conducting three Method 23 runs for
CDD/CDF is $21,000. This cost includes analysis of reagent
blanks and one" audit sample, and it assumes that the test is
conducted in conjunction with PM performance testing.
Hydrogen chloride emissions should be measured using EPA
Method 26. The estimated cost to conduct three runs in
conjunction with PM performance testing is approximately $5,000.
123
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Performance testing for CO should be conducted using EPA
Method 10 or 10B. The sampling and analysis cost for three
Method 10B runs in conjunction with PM performance testing is
approximately $4,000. The cost for instrumental CO testing
(Method 10 also would be about $4,000.
Method 9 is used to determine the opacity of emissions. The
estimated cost to conduct three Method 9 runs in conjunction with
PM performance testing is $1,000.
9.0 REFERENCES
1. Incinerator Sizing Guide and Waste Classification. Cleaver
Brooks product literature. May 1989.
2. Letter and attachments from R. Massey, Consumat Systems,
Inc., to J. Farmer, EPA/ESD. February 20, 1990, Response
to Section 114 information request to MWI manufacturers.
3. Letter and attachments from G. Swann, Joy Energy Systems,
Inc., to J. Farmer, EPA/ESD. February 23, 1990. Response
to Section 114 information request to MWI manufacturers.
4. Letter and attachments from K. Wright, John Zink, to
J. Farmer, EPA/ESD. March 2, 1990. Response to
Section 114 information request to MWI manufacturers.
5. Letter and attachments from J. Basic, Sr., John Basic,
Inc., to J. Farmer, EPA/ESD. February 26, 1990. Response
to Section 114 information request to MWI manufacturers.
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Inc., to J. Farmer, EPA/ESD. March 23, 1990. Response to
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7. Memorandum from D. Randall, MRI, to Project Files.
April 30, 1992. Summary of data provided by hospitals and
commercial facilities in response to Section 114
information request.
8. Memorandum from D. Randall and T. Holloway, MRI, to Project
files. April 30, 1992. Summary of process data from EPA
and non-EPA emissions tests.
9. Letter and attachments from T. Kendron, Simonds
Manufacturing Corp., to J. Farmer, EPA/ESD. April 9, 1990.
Response to Section 114 information request to MWI
manufacturers.
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Control District of Jefferson County. November 13, 1989.
124
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12
13
14,
15
16
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18
19
20,
National Incinerator, Inc.
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Radian Corporation. Medical Waste Incineration Emission
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Letter from G. Maxwell, Waste Management of North America,
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125
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21. Radian Corporation. Medical Waste Incineration Emission
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manufacturers.
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p. 4-13.
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26. Telecon. D. Randall, MRI, with M. Voight, Simonds
Manufacturing Corp. February 2, 1990. Design and
operation data for batch and pathological MWI's.
27. Memorandum from D. Randall, MRI, to Project files.
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model combustors.
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Inc., to W. Maxwell, EPA/ISB. January 29, 1990. Response
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information.
29. Letter and attachments from A. Dozier, Advanced Concepts,
Inc., to W. Maxwell, EPA/ISB. January 21, 1990. Response
to request for control equipment design and cost
information.
30. Telecon. M. Turner, MRI, with D. Sanders, Andersen 2000.
March 16, 1990. Design and operating parameters for APCD.
31. Letter and attachments from S. Sheppard, The Ceilcote Co.,
to W. Maxwell, EPA/ISB. January 31, 1990. Response to
request for control equipment design and cost information.
32. Letter and attachments from E. Mull, Interel, to
W. Maxwell, EPA/ISB. January 30, 1990. Response to
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126
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33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
Letter and attachments from P. Finnis, Procedair, to
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Letter and attachments from J. Childress, United McGill
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to request for control equipment design and cost
information.
Letter and attachments from W. Wiley, Consumat Systems,
Inc., to W. Maxwell, EPA/ISB. March 19, 1990. Response to
request for control equipment and cost information.
Fax transmission from W. Wiley, Consumat Systems, Inc., to
M. Turner, MRI. June 6, 1991. MWI's with Consumat's DI/FF
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Telecon. D. Randall, MRI, with a Commercial Medical Waste
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of MWI's and APCD's.
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Report, Volumes I, II, and III - Borgess Medical Center,
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Design
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43. Telecon. T. Holloway, MRI, with J. Childress, United
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44. Letter and attachments from G. Blizard, Jr., ThermAll,
Inc., to W. Maxwell, EPA:ISB. December 28, 1990. Response
to request for design and cost information about rotary
kiln combustors.
127
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45. Letter and attachments from R. Hosier, Sly Manufacturing
Company, to W. Maxwell, EPA:ISB. March 6, 1990. Response
to request for information about APCD's used with MWI's.
46. Telecon. D. Randall, MRI, with W. Wiley, Consumat Systems,
Inc. May 21, 1990. Design and cost information about
APCD's used with MWI's.
47. Telecon. D. Randall, MRI, with S. Shuler, Joy Energy
Systems, Inc. September 13, 1990. MWI costs.
48. Letter from J. Childress, United McGill, to W. Maxwell,
EPA:ISB. August 7, 1990. Design and cost information
about APCD.
49. Telecon. D. Randall, MRI, with E. Kniss, Procedair
Industries. July 27, 1990. Design and cost information
about APCD's.
50. Telecon. D. Randall, MRI, with J. Childress, United McGill
Corp. May 24, 1990. Design and cost information about
APCD's.
51. Letter from E. Mull, Interel Corp., to D. Randall, MRI.
September 24, 1990. APCD component costs.
52. Telecon. D. Randall, MRI, with S. Sheppard, Ceilcote.
June 17 and July 23, 1990. Design and cost information
about APCD.
53. Letter and attachments from S. Sheppard, Ceilcote, to
W. Maxwell, EPA.-ISB. June 25, 1990. Design and cost
information about APCD.
54. Letter and attachments from L. Henson, Andersen 2000, Inc.,
to W. Maxwell, EPA:ISB. June 5, 1990. APCD component
costs.
55. Telecon. D. Randall, MRI, with E. Mull, Interel Corp.
September 17, 1990. Design and cost information about
APCD's.
56. Telecon. D. Randall, MRI, with W. Wiley, Consumat Systems,
Inc. November 19, 1990. Design and cost information for
APCD's.
57. Letter and attachments from G. Maxwell, Waste Management of
North America, Inc., to W. Maxwell, EPArlSB. January 22,
1991. Costs for MWI's and APCD's.
58. Telecon. D. Randall, MRI, with G. Blizard, ThermAll, Inc.
February 11, 1991. MWI and APCD costs.
128
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59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
Memorandum from D. Randall, MRI, to project files.
February 1, 1991. Procedures for estimating MWI and APCD
capital costs.
Neveril, R.B. Capital and Operating Costs of Selected Air
Pollution Control Systems. GARD, Inc. Prepared for U. S.
EPA Office of Air and Waste Management. December 1978.
EPA 450/5-80-002. pp. 4-28 and 4-73.
Telecon. M. Caldwell, MRI, with G. Kraft, American Water
Works Association. March 13, 1989. Information regarding
nationwide residential and commercial water rates for
January 1989.
Municipal Waste Combustors-Background Information for
Proposed Standards: Cost Procedures. Prepared for U. S.
EPA Office of Air Quality Planning and Standards.
August 14, 1989. EPA 450/89-27a. p. 3.2-13.
OAQPS Control Cost Manual (Fourth Edition).
EPA 450/3-90-006. January 1990. p. 2-25.
Reference 64, p. 2-26.
Memorandum from S. Shoraka, MRI, to K. Durkee, EPA/ISB.
November 14, 1991. Costs for alternative methods of
medical waste treatment.
Incinerator specifications literature from Cleaver Brooks.
March 1987.
Economic Indicators. Chemical Engineering. Plant Cost
Equipment Index for October 1989. January 1990. p. 216.
Reference 61, pp. 4-25 and B-2.
Reference 64, p. 2-29.
Reference 64, p. 5-49.
Equipment Index for August 1986.
October 27, 1986. p. 7.
Memorandum from S. Shoraka and C. Hester, MRI, to project
files. August 4, 1992. Emission rates for MWI's.
Telecon. D. Randall, MRI, with C. Cutting, Sparrow
Hospital. July 23, 1990. Ash disposal procedures.
Telecon. D. Randall, MRI, with R. Poll, Valley City
Disposal. July 20, 1990. Ash disposal procedures.
Telecon. D. Randall, MRI,
Hospital. July 20, 1990.
with G. Druen, Evanston
Ash disposal procedures.
129
-------
76. Telecbn. D. Randall, MRI, with G. Lowe, Fairfax Hospital.
July 24, 1990. Ash disposal procedures.
77. Telecon. D. Randall, MRI, with P. Stearns, Borgess Medical
Center. July 20, 1990. Ash disposal procedures.
78. Telecon. T. Holloway, MRI, with L. Romesberg, Radian
Corporation. October 17-18, 1991. Cost of the activated
carbon injection equipment used during emission test at
Facility A.
79. Letter from B. Brown, Joy Environmental Equipment Company,
to T. Brna, EPArCRB. May 10, 1991. Cost of activated
carbon.
80. Telecon. D. Randall, MRI, with A. Jackson, Minnesota
Pollution Control Agency. January 4, 1991. Discussion of
retort incinerators.
81. Telecon. D. Kapella, MRI, with T. Gordy, Washington State
Department of Ecology. January 22, 1991. Discussion of
retort incinerators.
82. Telecon. D. Randall, MRI, with S. Shuler, Joy Energy
Systems, Inc. February 13, 1991. Secondary chamber
retrofit on MWI's.
83. Telecon. D. Kapella, MRI, with W. Wiley, Consumat Systems,
Inc. February 11, 1991. Secondary chamber retrofits on
MWI's.
84. Telecon. S. Shoraka, MRI, with P. Guller, Biomedical
Services, Inc. January 23, 1991. Costs for alternatives
to onsite incineration of medical waste.
85. Telecon. S. Shoraka, MRI, with L. Roberts, Bio-
Environmental Services, Inc. January 18, 1991. Costs for
alternatives to onsite incineration of medical waste.
86. Telecon. S. Shoraka, MRI, with D. Setley, Medical Disposal
Services, Inc. February 4, 1991. Costs for alternatives
to onsite incineration of medical waste.
87. Telecon. S Shoraka, MRI, with B. Borton, Med-Waste, Inc.
February 4, 1991. Costs for alternatives to onsite
incineration of medical waste.
88. Telecon. S. Shoraka, MRI, with P. Wall, Medical Area
Service Corp. February 4, 1991. Costs for alternatives to
onsite incineration of medical waste.
89. Memorandum from S. Shoraka, MRI, to project files.
December 10, 1990. Projections for new MWI population.
130
-------
90.
91.
92.
93.
94.
95.
96.
97.
98.
U. S. Environmental Protection Agency. Medical Waste
Incinerators - Background Information for Proposed
Standards and Guidelines: Industry Profile Report for New
and Existing Facilities. EPA-453/R-94-042a. July 1994.
pp. 73-75.
U. S. Environmental Protection Agency. GEM computer
program cost model. Emission Measurement Technical
Information Center. Research Triangle Park, NC. Prepared
by Entropy Environmentalists, Inc. March 21, 1991.
Memorandum from D. Randall, MRI, to project files. April
30, 1992. Summary of GEM costs from vendors.
Fax transmission from L. Gallaro, COSA Instrument
Corporation, to T. Holloway, MRI. December 13, 1991.
Design specifications and costs for portable emissions
monitors.
Fax transmission from C. Trent, Energy Efficiency Systems,
Inc., to T. Holloway, MRI. 'December 13, 1991. Design
specifications and costs for portable emissions monitors.
Telecon. T. Holloway, MRI, with C. Trent, Energy
Efficiency Systems, Inc. December 13, 1991 and April 22,
1992. Specifications and costs for portable CO monitors.
The OMEGA Temperature Handbook. Volume 27. OMEGA
Engineering, Inc. Stamford, Connecticut, p. N-65.
The OMEGA Instrumentation and Reference Yearbook.
27, Supplement. OMEGA Engineering, Inc. Stamford,
Connecticut, p. F-45.
Volume
Letter from S. Gaines, J.A. King & Company, Inc. , to D.
Randall, MRI. December 10, 1991. Price quotation for
floor scale.
99. Letter from S. Johnson, W.B.. Porter & Company, to D.
Randall, MRI. April 22, 1992. Price quotation for floor
scales.
100. Memorandum from T. Holloway, MRI, to R. Copland, EPArSDB.
August 31, 1992. Industry comments on Maintenance/
Inspection and Monitoring Programs for MWI's.
101. U. S. Environmental Protection Agency. Medical Waste
Incinerator Study: Emission Measurement and Continuous
Monitoring. October 8, 1992.
131
-------
-------
Appendix A
Cost Algorithm for Intermittent Combustor Annual Costs
A. Model parameters
1. Design waste charging capacity, Ib/hr
2. Operating hours, hr/yr
a. preheat phase
b. burning phase
c. burndown phase
3. Operating days, d/yr
4. Volumetric flow rate out of SC, dscfm
Factors
1,500
Model Combustors
600
200
156
2,340
1,248
312
4,747
156
2,340
1,248
312
1,899
156
1,716
1,248
312
633
B. Total capital investment (TCI)
1. Combustor cost, S=1.48*5817* Ib/h ~ 0.4537
C. Annual costs
1. Electricity
a. hp=0.0101*lb/hr+1.677
b. unit cost, S/kwh
c. $/yr=(0.746)(hp)(S/kwh)(hr/yr)
2. Natural gas
a. PC burner capacity, Btu/hr (129.1)(lb/hr) +
170,273
b. SC burner capacity, Btu/hr (1290)(lb/hr) +
297,036
c. preheat phase
(1) PC burner utilization rate, %
(2) SC burner utilization rate, %
d. burning phase
(1) PC burner utilization rate, %
(2) SC burner utilization rate, %
e. burndown phase
(1) PC burner utilization rate, %
(2) SC burner utilization rate, %
f. unit cost, S/1000 ft3
g. heating value, Btu/ft3
h. therefore, S/1,000,000 Btu
i. $/yr=(bumercapacities)(utiiization
rates)(hr/yr)(S/1000 ft3)(ft3/Btu)
3. Water
a. unit cost, $/l000 gallons
b. consumption, gpm
c. $/yr=(gpm)(60 min/hr)(burning phase hr/yr)
(S/1000 gal)
4. Operating labor
a. burning phase labor, percent
b. Ash removal, hr/day
c. wage rate, $/hr
d. $/yr=((percent/100)(hr/yr)+(ash hr/d)(d/yr))
($/hr)
5. Supervisory labor
a. $/yr=(0.15)(operating labor)
0.06
100
100
0
50
75
90
3.5
1000
3.5
0.77
50
12
$237,659 $156,822 $95,266
$2,820
1
$108
$1,297
0.5
$54
$516
363,923 247,733 196,093
2,232,036 1,071,036 555,036
$20,524 $10,128 $4,901
0
$0
1 0.75 0.5
$17,784 $16,848 $12,168
$2,668 $2,527 $1,825
A-l
-------
6. Maintenance labor
a. labor, Tir/8hr (for all operating hours)
b. wage rate, S/hr=(l.l)(S12/hr)
c. S/yr=(hr/8hr)(S/hr)(hr/yr)
7. Maintenance materials
a. S/yr=0.02*TCI
8. Ash disposal
a. ash, % of waste charge
b. disposal charge, S/lon
c. S/yr=(lb/hr)(buming phase hr/yr)
(ton/2000 lb)(ash %)(S/ton)
9. PC refractory replacement
a. Assume PC is enclosed in a cylindrical shell
(1) Horizontal cylinder for units with capacity
greater than 500 Ib/hr
(2) Vertical cylinder for units with capacity
less than 500 Ib/hr
b. PCvolume, ft~3
V=(0.304)(lb/hr) +26.05
c. L/D ratio
d. Internal diameter, ft
10.
e. Internal length, ft
f. Refractory thickness, in.
g. Refractory volume, ft ~3
(includes sides and ends of cylinder)
h. Unit refractory cost, S/ft^ 3
i. Total refractory cost, S
j. Insulation thickness, in.
k. Insulation volume, ft ~ 3
(outside of refractory on all walls)
I. Unit insulation cost, S/ft ~ 3
m. Total insulation cost, S
n. Refractory and insulation replacement
frequency, yr
o. Capital recovery factor (CRF)
p. Replacement cost, S/yr
=CRF*(refractory cost+ insulation cost)
SC refractory replacement
a. Assume SC for all combustor types is
enclosed in a cylindrical shell
b. Assumed UD ratio
c. SC volume, ft ~3
=(dscfm/0.9)'(2260/528)*(l sec)*(min/60 sec)
The design temperature of 1800 F was
used instead of the typical operating
temperature of 1700 F in this equation
d. Internal diameter, ft
e. Internal length, ft
=(V'4)/(3.1416'd~2)
f. Refractory thickness, in.
g. Refractory volume, ft3
h. Unit refractory cost, S/ft3
i. Total refractory cost, S
j. Insulation thickness, in.
k. Insulation volume, ft3
1. Unit insulation cost, S/ft3
m. Total insulation cost, $
n. Refractory and insulation replacement
frequency, yr
0.5
13.2
9
40
1.5
4.5
127
2
43
$3,089 $3,089 $2,574
$4,753 $3,136 $1,905
$6,318 $2,527 $618
482.05
$3,729
376.27
6.21
12.42
119.09
$15,124
57.71
$2,481
208.45
$2,164
150.52
4.58
9.15
65.72
$8,346
32.74
$1,408
86.85
4.5
127
2
43
8
0.18744
7.42
11.14
134.78
$17,117
64.56
$2,776
5.61
8.42
77.98
$9,904
38.19
$1,642
4.19
6.29
44.20
$5,614
22.29
$958
$1,232
50.17
3.17
6.35
32.45
$4,122
16.88
$726
A-2
-------
o. Capital recovery factor (CRF)
p. Replacement cost, $/yr
= CRF*(refractory cost+insulation cost)
11. Overhead
a. $/yr=(0.6)(all labor and maintenance
materials)
12. Property tax, insurance, and administration
a. S/yr=(0.04)(TCI)
13. Capital recovery
a. Equipment life, yr
b. Interest rate, percent
c. capital recovery factor
d. $/yr=(CRF)(TCI-refractory
replacement cost)
D. Total annual cost
1. $/yr=sum of annual costs above
0.18744
20
10
0.11746
$3,300 $1,828 $909
$16,976 $15,360 $11,084
$9,506 $6,273 $3,811
$27,528 $18,206 $11,083
$119,103 $83,437 $52,626
A-3
-------
-------
Appendix B
Cost Algorithm for 2-second Secondary Chamber Combustion Control
for all APCD Control Technologies
A. Total Capital Investment
1. 2-sec SC cost = 10.87*dscfm+12,674
B. Annual Combustor Control Costs
1. Additional Refractory Replacement Costs For 2-Second Secondary Chambers
a. Assume SC for all combustor types are enclosed in cylindrical shell
b. Assumed L/D ratio = 2:1
c. 2-second SC refractory replacement
(1) 2-sec SC volume, ft'3 = dscfm/0.9*2260R/528R*2sec*lmin/60sec
(2) 2-sec SC diameter, ft = (SC volume*2/3.1416) ~ 0.3333
(3) 2-sec SC length, ft = SC volume*4/(3.1416*(SC dia.) ~ 2)
(4) 2-sec SC refractory replacement cost, 2SRR =
(3.1416/4*(((0.75ft+SC dia.) ~ 2.-SC dia. ~ 2)*SC length)
+ 2*(3.1416/4*(SCdia)~2*(4.5 in.*l ft/12 in.)))*$127/lft3
(5) 2-sec SC insulation replacement cost, 2SIR =
(3.1416/4*(((0.75ft+0.333ft+SC dia.) ~ 2-(SC dia.+0.75) ~2)*SC length)
+ 2*(3.1416/4)*(SC dia+4.5/12) ~2*2/12)*$43/lft3
d. 1-second SC refractory replacement
(1) 1-sec SC volume, ft3 = dscfm/0.9*2260R/528R*lsec*lmin/60sec
(2) 1-sec SC diameter, ft = (SC volume*2/3.1416) ~ 0.3333
(3) 1-sec SC length, ft = SC volume*4/(3.1416*(SC dia.) ~ 2)
(4) 1-sec SC refractory replacement cost, 1SRR =
(3.1416/4*(((0.75ft+SC dia.) ~ 2-SC dia. ~ 2)*SC length)
+ 2*(3.1416/4*(SCdia)~2*(4.5 in.*l ft/12 in.)))*$127/lft3
(5) 1-sec SC insulation replacement cost, 1SIR =
(3.1416/4*(((0.75ft+0.333ft+SC dia.) ~ 2-(SC dia.+0.75) ~ 2)*SC length)
+ 2*(3.1416/4) *(SC dia+4.5/12) ~ 2*2/12)*$43/lft3
e. Additional cost for 2-sec refractory replacement, AC2SC = (2SRR+2SIR)-(1SRR+1SIR)
f. Additional annual cost for 2-sec refractory replacement, AAC2SC = AC2SC*0.11746
2. Natural gas
a. Fuel to raise operating temperature from 1700F to 1800F (all models), $/yr
= (0.32BTU/lb/F)*(28.51b/lbmole)*(100F)*(lbmole/385ft3))*
(ft3/1000 BTU)*(S3.5/1000 ft3)*(dscfm/0.9)*
(60min/h)*(total operating hr/d)*(d/yr)
= (0.000553 *dscfm)*hr/yr
B-l
-------
b. Fuel used during cooldown (intermittent and batch models), S/yr
= (0.32BTU/lb/F) * (28.51b/lbmole) * (1800F-(1800-300F)/2) * (lbmole/385f t3)) *
(ft3/1000 BTU)*(S3.5/1000 ft3)*(dscfm/0.9)*
(60min/h)* (cooldown operating hr/d)*(d/yr)
= (0.00415*dscfm)*hr/yr
3. Maintenance materials
a. S/yr=(0.02)*(TCI for Combustion Control)
4. Overhead
a. S/yr =(0.6)'(Additional maintenance materials)
5. Property tax, insurance, and administration
a. S/yr=(0.04)*(TCI for Combustion Control)
6. Capital recovery
a. CRF = 0.11746
b. S/yr=(CRF)*(TCI for Combustion Control - Additional refractory capital cost, AC2SC)
B-2
-------
Appendix C
Cost Algorithm for VS/PB Control Device
A. Total capital investment
1. APCDcost,S=A*dscfm+B
where A=
B=
B. Direct annual costs
1. Fan electricity
a. Form Figure 18, average fan hp=C*dscfm
where C=
b. Avg. unit electricity cost, S/kwh
c. $/yr=(0.746)*(hp)*(unit cost)*(hr/yr)
=(0.746)*(C*dscfm)*(S/kwh)*(hr/yr)
=(E*dscfm)*(hr/yr)
where E=
33.3
118,969
0.0205
0.06
0.000918
2. Pump electricity
a. From Figure 19, hp=(G*dscfm+H)
where G=
H=
b. S/vr=0.746*(G*dscfm+H)*($/lcwh)*(hr/yr)
=(I*dscfm+J)*(hr/yr)
where 1=
J=
3. Makeup scrubber water
a. From Figure 20, gpm=K*dscfm
where K=
b. Unit water cost, S/1,000 gal
c. S/yr=(K*dscfm)*(S/l,000 gal)*(hr/yr)*(60 min/hr)
=(M*dscfm)*(hr/yr)
where M=
0.00267
4.554
0.000120
0.2038
0.00512
0.77
0.000237
4. Operating labor
a. Operating labor required, hr/shift
b. Labor wage rate, $/hr
c. $/yr=(hr/shift)*(l shift/8hr)*($/hr)*(hr/yr)
=P*(hr/yr)
where P=
0.4
12
0.6
C-l
-------
5. Supervisory labor
a. Supervisory labor=0.15*(operating labor)
b. S/yr=0.15»(P)*(hr/yr)
=Q*(hr/yr)
where Q=
6. Maintenance labor
a. Maintenance labor required, hr/shift
b. Wage rate=l.l*(operating labor wage rate)
c. S/yr=(hr/shift)*(l shift/8 hr)*(operator S/hr)*(l.l)*(hr/yr)
-R»(hr/yr)
where R=
7. Maintenance materials
a. Materials cost=0.02*TCI
b. S/yr=0.02*(A*dscfm+B)
=RR*dscfm+SS
where RR=
SS=
8. Caustic (NaOH)
a. Assume stoichiometric amount of NaOH is added for reaction with acid gases
0.09
0.3
0.495
0.666
2379
b. HC1 in exhaust gas, lb/hr=(ppm HCl/l,000,000)*(lbmole/385 dscf)
*(dscfm)*(36.5 Ib HCl/lbmole HC1)*(60 min/hr)
=S*dscfm*(ppm HC1)
where S=
c. NaOH to neutralize HC1,
lb/hr-S*dscfm*(ppm HC1)* (40/36.5)* (1 Ibmole NaOH/1 Ibmole HC1)
=T*dscfm*(ppm HC1)
where T=
5.688E-06
6.234E-06
d. Dry NaOH cost, S/ton
e. Caustic cost, $/yr=(NaOH to neutralize HCi, lb/hr)*(S/ton)
•(ton/2,000 lb)*(hr/yr)
=(W*ppm HCl)*(dscfm)*(hr/yr)
where W=
9. Sewer charge
a. From Figure 21, blowdown, gal/min=X*dscfm
where, X=
b. unit cost, S/1,000 gal
c, S/yr=(X*dscfm)»(S/l,000 gal)*(60 min/hr) *(hr/yr)
s(Z*dscfm)*(hr/yr)
where Z=
400
1.247E-06
0.000747
2.00
8.964E-05
C-2
-------
C. Indirect Annual Costs
1. Overhead
a. S/yr=(60 percent) * [(all labor, in hr/yr)+(maintenance materials)]
=0.6*[(P+Q+R)*(hr/yr)+(RR*dscfm+SS)J
=(BB*h/yr)+PP*dscfm+QQ
where BB=
PP=
QQ=
2. Property tax, insurance, administration
a. $/yr=(4 percent)*(Total Capital Investment)
=(0.04)*(A*dscfm+B)
=CC'dscfm+DD
where CC=
DD=
3. Capital recovery
a. Equipment life, years
b. Interest rate, percent
c. Capital recovery factor
d. S/yr=CRF* (TCI)
=0.11746*((A*dscfm+B)
=EE*dscfm+FF
where EE=
FF=
D. Total annual costs
1. a. Sum of all annual costs
b. $/yr={((W*ppm HCl)+(E+I+M+Z))*dscfm+(J+P+Q+R+BB)}»(hr/yr)
+(CC+EE+PP+RR)*dscfm+(DD+FF+QQ+SS)
=(((W*ppm HC1)+AB)*dscfm+AC)*(hr/yr)+(AD*dscfm)+AE
where AB=
AC=
AD=
AE=
W=
0.711
0.3996
1428
1.332
4,759
20
10
0.11746
3.9114
13,974
0.00136
2.0998
6.3090
22,540
1.247E-06
C-3
-------
-------
Appendix D
Cost Algorithm for DI/FF Control Device
A. Total Capital Investment
1. APCD cost from Figure 6, $=PP*dscfm+QQ
where PP=
00=
B. Direct Annual Operating Costs
1. Fan electricity
a. Average fan hp from Figure 18=A*dscfm+B
where A=
B=
b. Avg. unit electricity cost, $/kwh
c. $/yr=(0.746)*(hp)*(unitcost)*(hr/yr)
=(0.746)*(A*dscfm+B)*($/kwh)*(hr/yr)
=(C*dscfm+D)*(hr/yr)
where C=
D=
2. Other electricity
a. Avg. is 22 percent of fan electricity, according to two vendors
b. $/yr=0.22*(C*dscfm+D)*(hr/yr)
=(E*dscfm+F)*(hr/yr)
where E=
F=
3. Makeup lime
a. No recycle, but the system includes a retention chamber
b. Avg. lime makeup, Ib/hr = (2.5 Ibmole lime/2 Ibmole HCl)*(ppm HC1/10E6)*
(Ibmole HC1/385 dscf HCl)*(dscfm)(60 min/hr)(MW lime)
=(1.44*10E-5)*(ppm HCl)*(dscfm)
=(G)*(ppm HCl)*(dscfm)
where G=
c. Lime cost, $/ton
d. $/yr=(G*ppm HCL*dscfm)*($ 100/ton)*(l ton/2000 lb)*(hr/yr)
=a*ppmHa)*(dscfm)*(rir/vr)
where 1=
4. Evaporative cooler water
a. Moisture in gas before cooler, percent
b. Moisture in gas after cooler, percent
c. Temperature of gas before cooler, F
d. Temperature of gas after cooler, F
e. Gas flow rate out of cooler from Figure 19, acfm=(K*(dscfm:in)+L)
where K=
63.8
407,498
0.0065
2.88
0.06
0.00029094
0.129
6.401E-05
0.0284
1.44E-05
100
7.200E-07
10
38
1800
300
2.26
423
D-l
-------
f. Unit water cost, $/l,OQO gal
g. Water added in cooler, ft3/min at 300 F=(acfm:out)*(% H20)-(acfm:in)*(%H20)
=(K*(dscfm:in)+L)*(0.38)
-(dscfm:in/0.9)*(0.1)*(760/528)
=M*dscfin+N
where M=
N=
h. S/yr=(M*dscfm+N)*($/l ,000gal)*(60 min/hr)*(lbmole/ft3 at 300 F)
*(18 lb/lbmole)*(l lb/8.33 gal)*(hr/yr)
=(P*dscfm+Q)*(hr/yr)
where P=
0=
5. Operating labor
a. Operating labor required, hr/shift
b. Labor wage rate, $/hr
c. S/yr=(hr/shift)*(l shift/8hr)*($/hr)*(hr/yr)
=R*(hr/yr)
where R=
6. Supervisory labor
a. Supervisory labor=0.15*(operating labor)
b. S/yr=0.15*(R)*(hr/yr)
-S*(hr/yr)
where S=
7. Maintenance labor
a. Maintenance labor required, hr/shift
b. Wage rate=l.l*(operating labor wage rate)
c. S/yr=(h/shift)*(l shifl/8 hr)*(operator $/hr)*(l.l)*(hr/yr)
-T*(nr/yr)
where T=
8. Maintenance materials
0.77
0.6989
160.7
0.0001257213
0.0289
1
12
1.5
0.225
0.5
0.825
a. Materials cost=O.Q2*TCI
b. S/yr=0.02*(PP*dscrm+QQ)
=BA*dscfm+CA
where BA=
CA=
9. Compressed air
a. Air required, ft3/l,000 ft3 filtered
b. Air cost, $/l,OOOft3
c. Air filtered=air flow in fabric filter
=(K*dscfm:in+L)
d. S/vr=(K*dscfm+L)*(ft3 air/1,000 ft3 filtered)*($/l,000 fO)*(60 min/h)*(h/yr)
=(U*dscfm+V)*(hr/yr)
where U=
V=
1.276
8150
2
0.16
4.3392E-05
0.00812
D-2
-------
10. Dust disposal
a. Inlet-outlet PM in gr/dscf at 14% O2 = PM
b. Inlet HC1 concentration in ppmdv at 14% O2 = HC1
c. HC1 removal efficiency, percent
d. Molecular weight of CaC12
e. Molecular weight of CaOH2
f. Assume dscfm:inlet=dscfm:outlet
g. PM capture, lb/hr=(PM)*(dscfm)*(60 min/hr)*(l lb/7,000 gr)
=W*dscfm*PM
where W=
h. HC1 reaction products captured, Ib CaCL2/hr
=(HC1/1,000,000)*(HC1 removal efficiency)*(dscfm)*(lbmole CaC12/2 Ibmole HC1)
*(MW CaC12)*(lbmole/385 scf)*(60 min/hr)
=X*dscfm*HCl
where X=
i. Unreacted lime captured4b/hr=(makeup lime)-(reacted lime)
=((G*dscfm*ppm HCl-(X*dscfm*ppm HC1))*(MW CaOH2/MW CaC12)
=1.44*10E-5*dscfm*(ppm HCl)-(8.217E-6)*(dscfm)*(ppm HC1)*(74/111)
=8.922* 10E-6*(ppm HCl)*dscfm
=(Z*HCl)*dscfm
where Z=
j. Unit disposal cost at municipal landfill, $/ton=DC
k. $/yr={(W*dscfm*PM)+((X+Z)*dscfm*HCl)}
*(1 ton/2000 lb)*(DC)*(hr/yr)
=(BB*PM+BC*HCl)*(dscrm)*(hr/yr)
where BB=
BC=
95
111
74
0.00857
8.217E-06
8.922E-06
40
1.71429E-04
3.42779E-07
11. Bag replacement
a. Avg. bag cost (for outlet cone, of 0.015 gr/dscf), S/ft2
b. Avg. gas flow in ff, acfm = (K*(dscfm:in)+L)
c. Avg bag life, years
d. Interest rate, percent
e. Capital recovery factor
f. Avg. bag area, ft2
g. Avg. G/C ratio, ft/min
h. Bag replacement labor wage rate, $/hr
i. Bag replacement time, hr/bag
j. Taxes and freight, percent added to bag cost
k. Total bag cost = (acfm, ff)*(bag cost)*(taxes and freight factor)/(G/C ratio)
= (K*dscfm+L)*($/bag)*(1.08)/(G/C ratio)
= DD*dscfm+EE
where DD=
EE=
1. Total replacement labor cost = (acfm, ff)*(wage rate)*(bag replacement time)/
(bag area)/(G/C ratio)
= (K*dscfm+L)*($/hr)*(hr/bag)/(ft2)/(G/C ratio)
= FF*dscfm+GG
where, FF=
GG=
2.5
2
10
0.5762
18
3.5
12
0.15
1.743
326
0.0646
12.09
D-3
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m. S/yr=(Total bag cost + Total labor cost)*(CKF)
=((DD*dscfm+EE)+(FF*dscfm+GG))*(0.5762)
=HH*dscfm+n
where HH=
n=
12. Cage replacement
a. Assume mild steel cages (actual units are galvanized)
b. According to the Cost Manual, for <100 cages, one
cage cost in Aug 1986 = (4.941-rt).163)*(bag area, ft2))
This equation is also used for >100 cages in this algorithm because it
1. simplifies the algorithm
2. is only slightly different than the appropriate equation. Consequently,
the difference in the total cost is negligible.
3. it results in a slightly higher cost than that estimated by the appropriate
equation. Therefore, it may better represent the cost of galvanized cages.
c. Avg. cage life, yrs (assumes replacement every other time the bags are replaced)
d. Interest rate, percent
e. Capital recovery factor
f. CE plant index ratio (Oct 89/Aug 86) = 357.5/317.4
g. Number of bags = (acfm in ff)/(G/C ratio)/(single bag area)
» (K*dscfm+L)/(G/C ratio)/(ft2)
=JJ*dscfm+KK
where JJ=
KK=
h. Assume cage replacement labor is the same as bag replacement labor
=FF*dscfm+GG
where FF=
GG=
i. S/yr={total cage costs + total labor cost}*(CRF)
S/yr={ [(one cage cost)*(number of bags)*(CE plant cost index)]+(FF*dscfm+GG)}
*(CRF)
={[4.941+0.163*(bag area, ft2)]*{JJ*dscfm+KK}*(357.5/317.4)+(FF*dscfm+GG)}
*(0.31547)
=LL*dscfm+MM
where LL=
MM=
C. Indirect Annual Costs
1. Overhead
a. S/yr=(60 percent)* [(all labor)*(hr/yr)+maintenance materials]
=0.6*[(R+S+T)*(hrAr)+(BA*dscfm+CA)]
=(NN*hr/yr)+DA*dscfm+EA
where NN=
DA=
EA=
2. Property tax, insurance, administration
a. S/yr=(4 percent)*(Total Capital Investment)
=(0.04)*(PP*dsc&n+QQ)
=RR*dscfm+SS
where RR=
SS=
1.042
195
4
10
0.31547
1.12634
0.03587
6.7143
0.0646
12.09
0.12075
22.6006
1.5300
0.7656
4,890
2.552
16,300
D-4
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3. Capital recovery
a. Equipment life, years
b. Interest rate, percent
c. Capital recovery factor
d. Bag replacement cost = (HH*dscfm+n)/0.5762
= TT*dscfm+UU
where TT=
UU=
e. Cage replacement cost = (LL*dscfm+MM)/0.31517
= VV*dscfm+WW
where W=
WW=
f. $/yr=CRF*(TCI-Bag replacement cost-Cage replacement cost)
=0.11746*((PP*dscftn-KK^-(TT*dscfm+UU)-(VV*dscfm+WW))
=XX*dscfm+YY
where XX=
YY=
D. Total Annual Cost
1. Sum of all annual costs
2. $/yr= {a*HCl+BB*PM+BC*HCl+C+EH-P+U)*dscfm
•KD+F+Q+R+S+T+V+ NN)} *hr/yr+(HH-fLL+RR+XX+B A+DA)*dscfm
+(n+MM+SS+YY+CA+EA)
=((BB*PM+AF*HCl+AB)*dscfm+AC)*(hr/vr)+(AD*dscfmHAE
where AB=
AC=
AD=
AE=
AF=
20
10
0.11746
1.8080
338
0.38276
71.6
7.2366
47,817
0.00052
4.274
12.993
77,374
1.063E-06
D-5
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1. REPORT NO.
EPA-453/R-94-045a
TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
2.
4. TITLE AND SUBTITLE
Medical Waste Incinerators - Background Information for
Proposed Standards and Guidelines: Model Plant Description
and Cost Report for New and Existing Facilities
7. AUTHOR(S)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Emission Standards Division (Mail Drop 13)
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
12. SPONSORING AGENCY NAME AND ADDRESS
Director
Office of Air Quality Planning and Standards
Office of Air and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
July 1994
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D1-0115
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
Published in conjunction with proposed air emission standards and guidelines for
medical waste incinerators
16. ABSTRACT
This report presents the design and operating parameters and costs for model plants that represent
the medical waste incinerator (MWI) source category. Costs are presented for both MWI's and air
pollution control equipment. The model plants are then used in subsequent environmental and economic
analyses. This is one in a series of reports used as background information in developing air emission
standards and guidelines for new and existing MWI's.
17.
a. DESCRIPTORS
Air Pollution
Pollution Control
Standards of Performance
Emission Guidelines
Medical Waste Incinerators
18. DISTRIBUTION STATEMENT
Release Unlimited
KEY WORDS AND DOCUMENT ANALYSIS
b. IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group
Air Pollution Control
Solid Waste
Medical Waste
Incineration
19. SECURITY CLASS (Report) 21. NO. OF PAGES
Unclassified 146
20. SECURITY CLASS (Page) 22. PRICE
Unclassified
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
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