EPA 340/1-76-013
JANUARY 1977
Stationary Source Enforcement Series
@M
y"l! X
MUNICIPAL INCINERATOR
ENFORCEMENT MANUAL
U.S. ENVIRONMENTAL PROTECTION AGENCY
_ Office of Enforcement
Office of General Enforcement
Washington, D.C. 20460
-------
MUNICIPAL INCINERATOR
ENFORCEMENT MANUAL
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Enforcement
Office of General Enforcement
Washington, D.C. 20460
January 1977
-------
This report was furnished to the Environmental Protection Agency by THC—
The Research Corporation of New England, Wethersfield, Connecticut - in
fulfillment of Contract No. 68-01-3173, Task #18. The contents of this
report are reproduced herein as received from the contractor. The opin-
ions, findings, and conclusions expressed are those of the author and not
necessarily those of the Environmental Protection Agency. Mention of
company or product names is not to be considered as an endorsement by the
Environmental Protection Agency.
The Stationary Source Enforcement Series of reports is issued by the
Office of Enforcement, U.S. Environmental Protection Agency, to report
enforcement related data of interest. Copies of this report are avail-
able free of charge to Federal employees, current contractors and grantees,
and non-profit organizations - as supplies permit - from the Air Pollution
Technical Information Center, Environmental Protection Agency, Research
Triangle Park, North Carolina 27711 or may be obtained, for a nominal
cost, from the National Technical Information Seivice, 5285 Port Royal
Road, Springfield, Virginia 22151.
Publication No. EPA 340/1-76-013
January 1977
ii.
-------
TABLE OF CONTENTS
SECTION PAGE
1.0 INTRODUCTION ................... 1
2.0 COMPLIANCE STATUS ................ 3
2.1 Statistics ................... 3
2.2 Compliance Profile ............... 4
2.3 Emission Limitations .............. 17
3.0 MUNICIPAL INCINERATION AND AIR POLLUTION ..... 23
3.1 Process Description .............. 23
3.1.1 Combustion ................. 23
3.1.2 Furnaces ................... 26
3.1.3 Grate Systems ................ 30
3.1.4 Charging of Solid Waste ........... 33
3.1.5 Residue Removal ................ 34
3.1.6 Exhaust Gas Treatment ............ 35
3.2 Environmental Impact .............. 37
3.2.1 Air Pollution - Particulate Matter ...... 37
3.2.2 Air Pollution - Gaseous Emissions ...... 41
3.2.3 Water Pollution ............... 41
4.0 AIR POLLUTION CONTROL TECHNOLOGY ......... M
4.1 Evolution of Particulate Controls ....... 44
4.1.1 Settling Chamber ............... 44
4.1.2 Wetted Baffle ................ 45
4.1.3 Mechanical Collector ............. 45
4.1.4 Wet Scrubber ................. 46
4.2 High Efficiency Control Devices ........ 47
4.2.1 High Energy Scrubbers ............ 48
4.2.2 Electrostatic Precipitators ......... 51
4.2.3 Fabric Filters ................ 56
5.0 FIELD INSPECTION TECHNIQUES ........... 58
5.1 Technical Considerations ............ 59
5.1.1 Process Evaluation .............. 59
5.1.2 Pollution Control Equipment Evaluation .... 65
5.2 Inspection Checklists ............. 71
5.2.1 Initial Inspection Checklist ......... 73
5.2.2 Compliance Test Evaluation Checklist ..... 80
5.2.3 Periodic Compliance Inspection Checklist
..
6.0 COMPLIANCE SCHEDULE DEVELOPMENT - BACKGROUND ... 90
6.1 General .................... 90
6.2 Air Pollution Control Equipment Costs ..... 92
6.2.1 Basis of Analysis .............. 92
6.2.2 Capita] Coots ................ 97
6.2.3 Annual I r.oA Operating Costs .......... 100
ill
-------
TABLE OF CONTENTS - CONTINUED
SECTION PAGE
6.3 Vendor Capabilities ............... 105
6.3.1 Regulatory and Enforcement Trends ....... 105
6.3.2 Demands on Equipment Suppliers ........ 105
6.3.3 Conclusions .................. 106
6.4 Timetable/Schedules ............... 106
6.4.1 Elements of Compliance Schedule ........ 106
6.4.2 Typical Compliance Schedules ......... 108
6.4.3 Input from Equipment Suppliers ........ Ill
6.4.4 Conclusions .................. Ill
6.5 Municipal Funding Practices ........... 112
6.5.1 Short-Term Options ............... 113
6.5.2 Long-Term Options ............... 113
REFERENCES
iv
-------
LIST OF FIGURES
FIGURE PAGE
2-1 Location of Municipal Incinerators in the
United States 9
3-1 Vertical Circular Furnace 27
3-2 Multicell Rectangular Furnace 28
3-3 Rectangular Furnace 29
3-4 Rotary Kiln Furnace 30
3-5 Traveling Grates 32
3-6 Reciprocating Grates 32
3-7 Rocking Grates 32
3-8 Circular Grates 32
3-9 Entrained Partlculate Emissions 39
3-10 Properties of Particulates Leaving Furnace 39
3-11 Typical Resistivity - Temperature Curves 40
4-1 Schematic Diagram of Gas Actuated Venturi Scrubber
with Cyclonic Mist Eliminator 49
4-2 Relationship between Efficiency and Pressure Drop
in Venturi Scrubbers 50
4-3 Schematic Drawing of Electrode Arrangement in a
Single-stage Electrostatic Precipitator 52
4-4 Cut-Away View of an Electrostatic Precipitator ... 52
4-5 Filter Baghouse with Mechanical Shaking 57
6-1 Elements of Municipality Decision Process to Effect
Incinerator Compliance 91
6-2 Municipal Incinerator Exhaust Gas Flow Rates(ACFM)
vs. Furnace Capacity (TPD) 94
6-3 Variation of Municipal Incinerator Exhaust Gas Flow
Rates (%) vs. Refuse Heating Value 95
-------
LIST OF FIGURES - CONTINUED
FIGURE PAGE
6-4 Variation of Municipal Incinerator Exhaust Gas Flow
Rates (%) vs. Temperature Entering Air Pollution
Control Equipment 95
6-5 Air Pollution Control Systems Capital Costs for Gas-
Quenching Chamber & Waste Heat Boiler 98
6-6 Air Pollution Control Systems Total Installed Costs -
Electrostatic Precipitators 99
6-7 Air Pollution Control Systems Total Installed Costs -
Venturi Scrubbers 100
6-8 Air Pollution Control Systems Operating Costs - Gas
Quenching Chamber 101
6-9 Air Pollution Control Systems Annual Operating Costs -
Waste Heat Boiler 101
6-10 Air Pollution Control Systems Annual Operating Costs -
Electrostatic Precipitator 102
6-11 Air Pollution Control Systems Annual Operating Costs -
Venturi Scrubber 103
6-12 Schedule for Installation of a Wet Scrubber for
Particulate Pollutant Control on a Municipal
Incinerator 109
6-13 Schedule for Installation of an Electrostatic Precipi-
tator for Particulate Control on a Municipal Incinerator 110
vl
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LIST OF TABLES
TABLE PAGE
2-1 Operating Municipal Incinerators in the United
States s
2-2 Closed Municipal Incinerators in the United
States 10
2-3 List of Abbreviations 16
2-4 Emission Limitations for Existing Municipal
Incinerators 18
4-1 Typical Electrostatic Frecipitator Design Parameters
for Incinerator Applications 55
4-2 Partial Listing of Electrostatic Precipitator
Installations 55
5-1 Incinerator Operating Conditions which Affect
Emissions 34
6-1 Summary of Annualized Costs - Venturi Scrubber . . . 1Q4
6-2 Summary of Annualized Costs - Electrostatic Precipi-
tator 104
vil
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1.0 INTRODUCTION
The total quantity of municipal solid waste generated In the United
States has been estimated at 5.5 pounds per capita per day.d' This must,
by one means or another, be disposed of. While there are several solid
waste disposal and reduction methods currently in practice, incineration
is an approach which minimizes refuse volume, destroys the bulk of noxious
odors and putrescible substances while maintaining maximum effective use
of available and scarce land near to the population centers which require
its use.
Incineration is a combustion process, and like all combustion pro-
cesses, it is a source of smoke, particulate matter, and a wide variety
of gaseous contaminants. Studies'2' have shown that approximately 8% of
the refuse collected in the United States is subjected to incineration
and that this percentage has remained relatively constant over the last
10 years. Today there are 108 municipal incinerators whose capacity is
in excess of 50 tons per day operating in the U.S. Emissions from most
of these units are uncontrolled or at best only partially controlled. In
fact, if all existing municipal incinerators were to just meet applicable
local, state, and federal regulations, particulate emissions from these
facilities would be reduced by an overall 86%.'2^
Nationwide, the compliance record of municipal incinerators with
state and local regulations is perhaps the worst of any major stationary
source category. As of July 1976, 75 out of 108 municipal incinerator
installations in the U.S. were not in compliance with appropriate regula-
tions. Of these 75, 23 were not even on a compliance schedule. Since
incinerators are generally located as a function of population density,
the impact of their emissions on public health and welfare la significant.
-1-
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Clearly, the control of pollutant emissions from this source category
is a problem with which environmental regulatory officials must reckon.
Accordingly, this Manual has been prepared to assist enforcement personnel
on both state and federal levels in initiating actions to effect compliance
with State Implementation Plan (SIP) requirements. The purpose of the
Manual is four fold:
o Supply to enforcement personnel a ready reference as to the
compliance status of each municipal incinerator within their
jurisdiction.
o Develop the basis for making field judgments regarding the
effectiveness of present air pollution controls extrapolating
findings to other similar units.
o Provide up-to-date information on the latest control device
technology, costs, vendors and design/delivery schedules.
o Suggest an effective and reasonable compliance schedule for
implementation by the incinerator owner.
This Manual is applicable to:
o Incinerators with a capacity in excess of 50 tons per day of refuse
burning capability.
o Incinerators designed specifically for and limited to the handling
of residential and commercial paper, cardboard, garbage, and
yard wastes.
o Incinerator Installations within the 48 contiguous states.
-2-
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2.0 COMPLIANCE STATUS
2.1 Statistics
Since 1920, 322 municipal incinerators have been built in the United
States with a total installed design capacity of nearly 100,000 tons per
day. However, in 1969 only 251 Incinerators with an aggregate design
capacity of 80,000 tons per day were actually operating. An Inventory con-
ducted by the Office of Solid Waste Management Programs (OSWMP)^3) showed
that as of May 1972 only 193, with a daily design capacity of 71,000 tons,
were operating. As of June 1976, the number had been further reduced to
108 with a total daily design capacity of approximately 43000 tons.
During the period 1945 to 1967, an average of over 13 separate in-
creases in installed design capacity took place each year, but fewer than
four per year have occurred since 1967. Possible reasons for the decline
in construction and in the increased closing of old Incinerators are:
o Many municipalities presently have sufficient incinerator
capacity.
o The high costs associated with upgrading existing Incinerators
to control air pollutant emissions are forcing municipalities
to opt for less expensive sanitary land fill operations.
o Municipalities requiring additional processing capacity are
putting off construction plans due to high capital and operating
costs and are overburdening their present units.
The decline in utilization of municipal incinerators may be accelera-
ted further if political jurisdictions at various levels continue to set
standards more stringent than those of the Federal Government. Federal
standards for new or modified units are established at a level that the
best available technology can achieve with reasonable costs. In addition,
resource recovery systems and new systems for thermal processing of solid
-3-
-------
wastes such as pyrolysis, gasification, vortex incinerators, and utility
boilers which can process solid wastes are being developed. Communities
which require processing to achieve volume reduction in the future may
utilize these new systems instead of conventional municipal incinerators.
Of the 108 municipal incinerators currently operating in the United
States, 33 are in compliance with their appropriate s :ate or local air
pollution control regulations. Of the remaining 75 operational units,
45 are on compliance schedules, 23 are not on compliance schedules, and
7 have schedules pending. Included in the list of 108 incinerators are
7 which were built after December 23, 1971. Emissions from these facil-
ities are regulated by New Source Performance Standards (NSPS). A total
of 197 additional municipal incinerators have been shut down and are no
longer operational. More than half of these were closed since 1970, in-
dicating the effect of major environmental leg.slation.
2.2 Compliance Profile
Table 2-1 lists all the municipal incinerators currently operating
within the 48 contiguous states. Information pertaining to size, process,
pollution control equipment and compliance status is also summarized for
each unit. The listing is organized in terms of the ten EPA regions and
subcategorized for each state within the region to facilitate use of this
Manual by both state and federal officials. As new, or more up-to-date
information becomes available, Table 2-1 may be updated. Sources which
are subject to NSPS are included in the Table and are denoted by an asterisk.
-4-
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TABLE 2-1
OPERATING MUNICIPAL INCINERATORS
IN THE UNITED STATES
EPA
.**
I
II
State
KA
U
RI
CT
n
'•"•«——•— "—
•Reading
Holyoka
Framlngham
Hlnchcitcr
•Bralntreo
•E. Brldgevater
Marlboro
Manchester
Durham
Pawtucket
Ansonla
City of Bridge-
port
Bridgeport
I. Hart ford (old)
1. Hirtford(nev)
Greenwich (old)
preenvlch(new)
New Caen
New Haven
Hew LoDdoo
Horvalk
Stamford
Stamford
Stratford
Wsterbury
Wait Hartford
Mt Vernon
Babylon «1
Beacon
Buffalo
East Cheater
Frceport
Garden City
lellp 11.12
Nerrlck
Oceanilde
New Hyde Park
Roalyn Harbor
Hun ting ton 11
Huntlngcon 12
Long Beach
New Rochelle
Oyeter Bay fl
Oyeter Bay 12
*y«
Seeredale
Tonawanda 11
Tonewande 12
Valley Strean
19} John St
Berkahlre St
Mt Valte Ave
Swanton St
Ivory St
E. Brldgeweter
Marlboro
Maple St
Durban Point Rd
Crotto Ave
N. Division St
Asylum St
Boatwlck Ave
141 Ecology Dr
141 Ecology Dr
Town Hall Annex
Town Ball Annex
Meln St
260 Mlddletown
Ave
100 Trunbull St
'eat Ave
Barborvlew Ave
Barborvlev Ave
Town Hall
City Hell
8 South Main
St
Mt Vernon
leaa St.
Babylon
Beacon
Buffalo
East Chester
reeport
Garden City
lallp
Herrlck.Henp-
etead
Oceans Ide,
Hcmpstead
. Heaps teed
oslyn Harbor
untlngton
luntington
Long Beach
ew Rochelle
Oyster Bay
(Bethpage)
irster Bay
Rye
Sceredele
enawanda
onevenda
alley Stream
Siie-TPD
144
225
200
100
240
300
125
400
200
200
300
200
288
ISO
250
144
720
120
360
210
360
240
300
3SO
600
300
100
600
200
ISO
175
300
700
750
250
600
150
150
200
400
500
500
240
150
100
250
200
SO
SB
83
67
240
300
101
50
115
150
160
250
ISO
ISO
125
150
100
600
60
160
160
156
110
250
200
300
33
575
67
100
500
200
190
49S
150
ISO
240
28S
333
46
30
US
Proceee Description
Type
C
B
C
B
C
C
C
I
C
C
C
B
B
ft
C
B
C
C
C
B
C
C
C
C
B
1
B
B
B
B
B
B
C
C
B
C
B
C
B
-
B
C
B
B
.
C
Crete
MC
MA
T
RK
T
T
HA
T
RK
RK
CI
RK
T
RK
RK
ME
T
RK
T
.
T
CI
CI
CI.MB
CI.HE
RK
CI.ME
RK
RK
R
T
CI.ME
RK
CI.ME
RK.T
RK
CI.ME
-
—
RK
CI.ME
CI.ME
U
T
Furnace
Control Equlpicnt
ESP
DSC
WSC.SCR
USC.C
ESP
PF
SCR
SCR
SCR
use
DSC
VSC
WSC.DSC
use
DSC
VSC
SCR
VSC
DSC
VSC. SCR
ESP
ESP
VSC
VSC
VSC
VSC
VSC
VSC
VSC
VSC
VSC
None
ESP
VSC
SCR
C
DSC. SCR
VSC
VSC
VSC
VSC
VSC
VSC
DSC
VSC
VSC
Kliiclency
(Z)1
93
(10)
40
90
99.9
(95)
(BO)
(SO)
60
60
IS
15
IS
60
15
35
80
35
15
95
90
90
35
15
(JO)
( 0)
(10)
(20)
(20)
(20)
(20)
(90)
(20)
(80)
(30)
(90)
(20)
(20)
(20)
(20)
(20)
(20)
(10)
(20)
(20)
Compliance
-STaT
In
/
/
/
J
J
/
/
/
/
/
/
/
/
/
/
ua
hit
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
^
/
/
/
j
/
/
/
/
t
/
/
/
/
/
/
Schc
Yes
/
/
/
/
/
/
/
/
/
Pend
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
IGTY
No
/
/
/
ng
/
/
/
/
/
Compliance
Date
8/76
8/76
1/75
2/1/77
2/1/77
10/1/76
10/1/76
2/1/77
2/1/77
3/1/77
12/1/76
2/1/77
10/1/76
10/1/76
1/78
1978
1978
1978
1977
1978
1980
1/78
1/78
1978
Coeewnie
and
Complying
Shutdown
Shutdown
Closed 5/76
to re-open
eusmwr 76
Not meeting
Schedule
Teatlng
Shutdown
Shutdown
Shutdown
Shutdown
Shutdown
Shutdown
Shutdown
Shutdown to
Upgrade
Shutdown
Shutdown
Shutdown
Not meeting
Schedule
This la new
proposed
shutdown
date
Shutdown
Shutdown
Shutdown
Shutdown
This Is new
proposed
shutdown
date
This Is nsw
propoeed
shutdown
date
This ie new
proposed
shutdown
data
Shutdown
Sources subject to Mew Sourcs Performance Stenderde (HSPS)
(''Values In pnrrntheses art estimated efficiencies
As of
-5-
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TABLE 2-1 (CONTINUED)
OPERATING MUNICIPAL INCIXEIATOIS*
IN THE UNITED STATES
EM
••1.
Ill
rv
T
£1111
PA
VA
DC
KD
FA
R
n
n.
HI
Incinerator Rama
•hit! Pl«ln«
Yonkera
Cenaevoort
South Short
Creenpoint
Hamilton Ave
SV BrooUyn
Betta An
Ambrldge
Bradford
Delaware Co. 11
Delaware Co. 12
Delaware Co. 13
lower Marlon
m Philadelphia
B. Cat. Phila-
delphia
Rod Lion Borough
White Hareh
City of Alexan-
dria
Portsmouth
Banning Id *5
Pulaakl 14
Fort St Joe
Ft Lauderdale
Brovard Co. 11
Bmmrd Co. 11
City Hill-
Dinner Key
Dido County
Tampa
•Orlando
City of Peril
Loultvlllo
•UwUburg
•Haehvllle
Thermal
Calumet
Chicago HW
Chicago SW
Cicero Incln.
Inc.
S.B. Oakland
Co.
Centrel Wayne
Co.
Croiee Ft.
Clinton
Addreee
White Plain.
Tonkari
Row York City
BrooUyn
BrooUyn
BrooUyn
BrooUyn
Queena
1001 Merchant St
Bradford
Feltonvllle
Folcroft
Broonall
1300 Woodbine
Doolno and
Unbrla St
Del and SP
Garden St
Rod Lion
White Mareh
Alexandria
Portemouth
Wachlngton DC
Baltimore
Port St Joe
1300 R Vlngate
Ft Lauderdale
Pompano Beach
Hleal
R. Miami Beach
Mckey and Alamo
Dr
MeOoud Id
Stewart St
Clay and
Herlvater
Leviaburi
Haahvllle
ChlcaBO
Chicago
1100 Pending
3B1S S. Lartmla
Kadleon Blight!
Dearborn Heighti
Groin Point
Sl«e-TPD
PeeUn
400
560
1000
1000
1000
1000
1000
1000
ISO
200
500
500
500
250
600
600
300
350
1200
96
450
300
300
900
300
900
100
100
1000
<0
720
1200
1600
1200
720
600
•50
600
180
480
660
750
750
750
620
35
119
330
124
320
226
585
570
1000
39
428
300
300
900
850
50
1400
720
.
600
450
Proceie Deecriptlon
B
B
C
C
C
C
C
C
B
C
C
C
C
C
C
_
-
C
B
C
-
C
C
C
C
.
C
-
B
C
_
C
B
C
C
-
C
.
.
Crate
RK
CI.HE
T
T
T
T
T
T
RK
RK
T
T
T
RK
T
T
_
-
RK
-
T
-
R
R
1
R
-
-
R
T
.
.
RK
R
R
-
t
t
.
Furneee
K
.
X
SA
K
.
W
K
.
Pollution
use
WSC
DSC.WSC
DSC.FF
None
WSC. DSC
WSC
DSC.FF
SCR
SC
SC
LSCR
LSCR
C
LSCR
.
-
WSC. DSC
wsr
ESP.C.VSC
ESF.WSC
SCR
WSC
SCR
SCR
SCR
ESP
SCR
-
WSC
WSC
SCR
C.SCR
WSC
ISP
WSC
C
WSC, SCI
ICR.VSC
.
Efficiency
(1)1
(20)
(20)
(30)
(95)
(30)
(2C>
(95)
65
70
85
85
(30)
SO
_
-
(30)
(20)
(99)
(99)
99
(20)
87
95
80
(90)
(80)
-
(20)
(20)
(95)
98.5
(20)
96.8
(20)
50
(90)
90
.
So
/
/
/
/
/
/
/
/
/
/
/
/
/
III
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
Schc
J
^
j
j
/
/
/
^
^
j
Fen
/
Pen
Pen
/
Pat
lule
/
/
/
/
/
/
/
/
/
ling
/
ling
ling
ling
/
Finding
Conpliance
1980
1/78
1977
1976
1976
1977
1978
1978
1975
9/24/76
9/24/76
7/15/76
3/11/77
CoBBcnta
and
CoBpljrlng
Thli ie new
propoeed
ebutdown"
date
Tbie ie new
propoied
ehutdown
date *
Will Shut-
down
Upgrade with
ESP
Upgrade with
ESP
Coart Action
Will be In
Compliance
Summer 1976
Key be
etendby In
1979
Not meeting
Schedule
Not meeting
Schedule
Being
Tooted
Under Con-
etruetlon
•
Will Up-
grade
Will Utf
grade
Shutdown
Will Up-
grade
Court Suit
Feeding
Source! lubjccc to Nrv Source Performance Standard! (NSPS)
"'Values in pnrrntheiei ere estimated rfflclencici
<2>Ai of 6/15/76
-6-
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TABLE 1-1 (CONTINUED)
OPIMTINC MUNICIPAL INCINERATORS
IN THE UNITED STATES
(2)
RPA
EM.
VI
fit
VIII
State
US
OB
U
LA
MO
or
Incinerator Hana
City of Sheboy-
DePere Aehmu-
benon
City of Green
Bay
City of Vaukeeha
City of ClevB-
Clty of Euclid
City of Laketraod
1. Montgowry
Co.
8. Montgomery
Co.
Miami County
Ka*t Chicago
Beat Side
Alglera
Shroveport
N. St. Louie
S. St. Loula
Weber County
'2. 3
•Ogden
Addreaa
307 S. Wlldmod
Leonard St
N. Military Ave
900 Sentry Dr
3727 Ridge Road
27700 Lakeland
12920 Berea Rd
6600 Webeter St
Moraine
2200 North Dr
Beat Chicago
New Orleana
No* Orleana
Shreveport
B. Grant St
South Plrat
2599 A. Ave
Ogden
Ogden
Slie-TFD
DeeUn
240
100
500
200
15C
600
600
150
400
200
230
400
400
300
130
Operational
227
32
173
244
46
165
383
383
113
125
560
400
210
130
Proceae Deacrli tlon
Type
C
B
B
C
B
B
B
C
C
C
C
C
C
•
—
-
.
Crate
RK
-
-
U
RK
MA
T
T
RK
-
.
T
RK
_
-
_
fvirnaca
K
K
Pollution
Control Equipment
Type
WSC
WSC
-
•
WSC
WSC
DSC
SCR
SCR
SCR
SCR
DSC.C
C
HSC.C
SCR.WSC
SCR
DSC. SCR
ESP
Efficiency
(20)
(20)
-
(20)
(20)
(U)
87
87
-
83
(40)
(30)
(30)
88
88
47
(95)
CoBpllanca
Statue
in
'
/
'
hit
/
/
'
'
/
/
/
/
'
j
/
'
/
Schedule
Yea
/
/
/
/
'
/
/
Pel
J
NO
/
/
'
^
ling
Compliance
Date
7/1/75
9/1/76
4/1/78
4/1/78
8/1/76
12/76
12/76
5/15/78
CoBBente
and
Act lone
Referred to
Att.Cenerel
Referred to
Au.Ceneral
Hodlf. to
Reaource
Recorery
Hodlf. to
Reaource
Recovery
Sbutdom
Shutdovn
'source* aubject Co New Source Perfonence Stenderde (HSPS)
^^Veluea In pnrentheae* are eatfBated efflclenclee
<2>Aa of 6/15/76
-7-
-------
Of the 108 municipal incinerators operating in the United States,
87 are In the northeastern quarter* (Figure 2-1). Of these, 63 are
in the area designated as the "Incinerator Belt" (are.) enclosed with the
dashed line box shown on Figure 2-1). Thus, almost two-thirds of the total
number of incinerators in this country are concentrated in only 0.06 percent
of the land area where 13 percent of the nation's population live.
A total of 197 municipal incinerators which were once operational
have been shut down. Table 2-2 lists these units and the date that each
was closed, to the extent that such information was known.
The data presented in Tables 2-1 and 2-2 were obtained from the
following sources:
o Compliance Data System (CDS) printout updates.
o A document prepared by Vulcan-Cincinnati, Inc. entitled
"Air Pollution Control Compliance Analysis Report on
Municipal Incinerators."
o Communications with EPA regional officials.
o Communications with State environmental officials.
Due to the quantity of information presented, abbreviations have
been employed where appropriate. A description of these abbreviations is
found in Table 2-3.
*This includes: New Hampshire, Rhode Island, Vermont, Massachusetts,
Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland,
Virginia, Kentucky, Ohio, Indiana, Illinois, Michigan, Minnesota, and
Maine.
-8-
-------
Figure 2-1
Location of Municipal Incinerators in the United States
-------
TABLE 2-2
CLOSED MUNICIPAL INCINERATORSC * )
IN THE UNITED STATES
Region
I
State
CT
MA
RI
Name
Middletown
Middletown
Derby
New Britain
New Milford
West Haven
Darien (//l,#2,//3)
Hartford
Fall River
Pittsfield
Somerville
Cambridge
Brookline
Lawrence
Newton
Worcester
Marblehcad
Water town
Belmont
South Bay, Boston
New Bedford
Waltham
Wellesley
Dedha n
Salem
Lowell
Weymouth
Fall River
Newport
Providence
Providence
Providence
Warwick
Woonsocket
Newport
Address
Middletown
Middletown
Derby
New Britain
New Milford
West Haven
Darien
70 Incinerator Rd.
Fall River
Pittsfield
Somerville
90 Bolton St.
815 Newton St.
Marston St.
130 Rumford Ave.
Ballard St.
Marblehead
Grove St.
1130 Concord St.
South Bay Ave.
Shawmut Ave.
165 Lexington St.
Great Plain Ave.
141 Washington St.
Salem
West ford Ave.
94 Wharf St.
Robeson St.
Adam Kalbfus Rd.
Fields Point
Fields Point
Fields Point
Warwick
Cumberland Hill Rd.
Public Works Comm.
Date
Closed
1969
1969
1969
1969
1976
1975
1969
1974
1971
1975
1974
1975
1973
1975
1974
1974
1975
1974
1975
1975
1974
1975
1975
1976
1976
M.973
VL974
1975 -
of 6/15/76
-10-
-------
TABLE 2-2 (CONT.)
CLOSED MUNICIPAL INCINERATORS<]>
IN THE UNITED STATES
Region
II
III
State
NY
NJ
PA
Name
Buffalo
Middle town
Elmira
Schenectady
Bronx, N.Y.
Flushing
Glen Cove
Larchmont
Amsterdam
Babylon
Cheektowaga
Corning
Troy
West Seneca
Harrison
Rochester
Binghamton
Niagara Falls
Poughkeepsie
Rochester
NYC
N. Tonawanda
Babylon //2
Newburgh
Port Chester
Hackensack
Atlantic City
Gloucester City
Pennsauken
Woodbridge
Jersey City
Ewing Township
Ambridge
Bloomsburg
Meadville
Allentown
Harrowgate
SE Philadelphia
Bertram
NE Philadelphia
Ab ing ton
Address
Buffalo
Middle town
Elmira
Schenectady
Bronx, N.Y.
Flushing
Glen Cove
Larchmont
Amsterdam
Babylon
Cheektowaga
Corning
Troy
Vest Seneca
Harrison
West Side
Binghamton
Niagara Falls
Poughkeepsie
East Side
74th St.
N . Tonawanda
Babylon 92
Newburgh
Port Chester
Hackensack
Atlantic City
Gloucester City
Pennsauken
Woodbridge
Jersey City
Dover & Stony Ave.
Ambridge
Bloomsburg
Meadville
Allentown
G & Ramona St.
7th & Pattison
Philadelphia
Wheatsheat & Delaware
Jefferson Ave.
Date
Closed
1970
1968
1968
1967
1969
1969
1953
1958
1961
1976
1968
1964
1962
1974
1976
1966
1972
1975
1975
1975
1975
1971
of 6/15/76
-11-
-------
TABLE 2-2 (CONT.)
CLOSED MUNICIPAL INCINERATORS^ ! )
IN THE UNITED STATES
Region
IV
State
VA
D.C.
MD
WV
FL
AL
GA
Name
Staunton
Arlington County
Norfolk
Alexandria
Roanoke
Norfolk
Fort Tot ten
Georgetown
Mt. Olivet
0 St.
Montgomery County
Salisbury
Reedbird
Charleston
Jacksonville
Jacksonville
Jacksonville
Hollywood
Coral Gables
Clearwater
St. Petersburg
Orlando
City of Orlando
Bessemer
Atlanta
Atlanta
Hartsfield
Address
Staunton
Court House
Norfolk
Alexandria
Roanoke
Norfolk
Fort Tot ten
31 St. 0 South NW
1833 W. Va. Ave.
1st & 0 St. SE
Montgomery County
Salisbury
Reedbird
Charleston
Southside
Jacksonville
Jacksonville
Hollywood
Coral Gables
Clearwater
St. Petersburg
Orlando
800 N. Fairville
Bessemer
Mayson
1-285 & Lawrenceville
Hartsfield
Date
Closed
1972,
1975
1973
M.970
1972
1972
1971
1972
1972
1975
1975
1975
1973
1968
^1964
1973
1973*
of 6/15/76
-12-
-------
TABLE 2-2 (CONT.)
CLOSED MUNICIPAL INCINERATORS
IN THE UNITED STATES
Region
V
State
KY
MI
OH
MN
Name
Lexington
Lexington
Winchester
Frankfort
Ecorse
Hamtramck
Hamtramck
Detroit
NW Detroit
Trenton
River Rouge
Detroit
Detroit
Cincinnati
Cleveland
Sidney
E. Cleveland
Columbus
Lima
Warren
Rocky River
S. Euclid
Bedford
Maple Heights
Rocky River
Dayton
Cleveland Heights
Parma
Dunbar
Barberton
Youngs town
Sharonville
Norwood
West Fork
Center Hill
Cheviot
St. Louis Park
Minneapolis
Minneapolis
Address
Lexington
Lexington
Winchester
Frankfort
Ecorse
Hamtramck
Hautramck
24 ;h St.
NW Detroit
Trenton
River Rouge
St. Jean
Central
Red Banl.
Cleveland
Sidney
E. Cleveland
Columbus
Lima
Warren
Rocky River
S. Euclid
Bedford
Maple Heights
Rocky River
Dayton
Cleveland Heights
5311 W. 130th St.
Cincinnati
Barberton
320 Cedar
Cincinnati
Cincinnati
Cincinnati
5500 Center Hill
Cincinnati
St. Louis Park
Minneapolis
Minneapolis
Date
Closed
1973
1973
1972
1974
1968
1966
1971
1970
1970
1970
1975
1971 & 1976
1971
1969
1969
1969
1963
1969
1969
1967
1969
1969
1969
1967
1969
•x.1968
M.966
1976
1973
•v.1970
•x.1970
1974
M.970
1975
1976
1976
1969
•^1970
M.970
of 6/15/76
-13-
-------
TABLE 2-2 (CONT.)
CLOSED MUNICIPAL INCINERATORS^
IN THE UNITED STATES
Region
V
State
WS
IN
IL
Name
Kenosha
Kenosha
West Bend
Port Washington
Neenah-Menasha
Oshkosh
Kewaskum
Wauwotosa
Racine
Racine
Racine
Racine
Oshkosh
Milwaukee
Fond Du Lac
Green Bay
Green Bay
Monroe
Monroe
Merrill
Milwaukee
West Allis
Whltefish Bay
Shorewood
Nekoosa
Indianapolis
New Albany
Bloomlngton
Rosemont
Aurora
Skokie
Chicago
Evans ton
Melrose Park
Shlller Park
Address
Kenosha
Kenosha
West Bend
306 North Park
Garfield Ave.
639 Dempsey Trail
Kewaskum
Wauwotosa
Racine
Racine
Racine
Racine
Oehkosh
Milwaukee
Fond Du Lac
Green Bay
Green Bay
Monroe
Monroe
Merrill
Milaukee
West Allis
Whltefish Bay
Shorewood
Nekoosa
Indianapolis
New Albany
Blooming ton
Rosemont
Aurora
Skokie
Chicago
Evans ton
Melrose Park
Shiller Park
DatO
Closed
1969
1969
1969
1976
1975
1975
1973
1973
1973
1971
1971
1971
1961
1973
1974
1973
1973
1968
1971
1972
1972
1972
1972
1967
1962
1970
of 6/15/76
-14-
-------
TABLE 2-2 (CONT.)
CLOSED MUNICIPAL INCINERATORS^
IN THE UNITED STATES
Region
VI
VII
IX
State
TX
LA
NE
CA
Name
Fort Worth
Fort Worth
Fort Worth
Houston
Houston
Houston
Amarillo
Gretna
Jefferson Parish
Jefferson Parish
New Orleans
New Orleans
New Orleans
Omaha
Beverly Hills
Pomona
Glendale
Santa Monica
Los Angeles
Los Angeles
Address
Fort Worth
Fort Worth
Fort Worth
Peterson
Velasco St.
Holmes Rd.
Gretna
Jefferson Parish
Jefferson Parish
7th St.
Florida Ave.
St. Louis St.
Omaha
Beverly Hills
Pomona
Glendale
Santa Monica
Gaffey St.
Lacy St.
Date
Closed
1975
•v 1970
•v. 1970
•v 1970
1976
1976
1976
1970
1956
1955
(1)
As of ft/15/76
-15-
-------
POLLUTION CONTROL EQUIPMENT
Settling Chamber - SC
Wet - WSC
Dry - DSC
Cyclone - C
Scrubber - SCR
Low Energy - LSCR
High Energy - HSCR
Electrostatic Preclpitator - ESP
Fabric Filter - FF
PROCESS/MECHANICAL CONFIGURATION
B - Batch
C - Continuous
Grate
T - Traveling Grates
R - Reciprocating Grates
RK - Rocking Grates
CI - Circular Grates
MA - Manual Stoking
ME - Mechanical Stoking
Furnace
K - Kiln
SA - Starved Air
WW - Water Wall
Table 2-3
List of Abbreviations
-16-
-------
2.3 Emission Limitations
There are eleven sets of units which are presently utilized to define
particulate emission limitations from municipal incinerators in the United
States. There is also a twelfth, pounds per ton of refuse charged, which
Is quite popular although it is not used as a legal standard. All twelve
sets of units are listed in the table below:
1. gr/scf at 12% C02
2. lb/100 Ib. dry refuse charged
3. Ib/hr
4. gr/scf
5. lb/1000 Ib. gas at 50% excess air
6. Ib/hr per Ib/hr charge
7. lb/1000 Ib. gas
8. gr/scf at 7% 02
9. gr/scf at 50% excess air
10. lb/106 btu
11. lb/1000 Ib. gas at 12% C02
12. Ib/ton fuel charged
A complete listing of all the state regulations for particulate
emissions for incinerators is presented in Table 2-4. In order to permit
the comparison of regulations on a nationwide basis, the actual value
of each regulation has been converted to a common set of units - grains
per standard cubic foot of flue gas corrected to 12% C02- This set of
units was chosen because it appears to have the most widespread use
and because the New Source Performance Standard for municipal incinera-
tors incorporates these units. The conversion calculations from the
specified regulation to the gr/scf @ 12% CX>2 equivalent were accomplished
using the following conversion factors:*
1 gr/scf @ 12% - 1.68 lbs/1000 Ibs flue gas at 50% excess air
- 1.89 lbs/1000 Ibs flue gas at 12% C02
*Based on refuse of 4,450 btu/lb. 1U1V
-17-
-------
TABLE 2-4
EMISSION LIMITATIONS FOR
EXISTING MUNICIPAL INCINERATORS
State
AL
AK
AZ
AR
CA
CO
CT
DE
FL
GA
ID
IL
Regulation
Value
.1
.2
.3
.2
.1
.17
.2
.3
.3
.1
.15
.08
.4
2.0
5.0
.08
.1
.08
.1
.2
0.2
.08
.02
.05
.1
Units
lbs/100 Ibs charged
lbs/100 Ibs charged
gr/scf
gr/scf
gr/scf
lbs/1000 Ibs gas
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
lbs/1000 Ibs
Ibs/hr
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
lbs/100 Ibs charged
gr/scf
gr/scf
gr/scf
gr/scf
Corrected To
-
12% C02
12% C02
12% CO,
12% CO,
12% C02
12% CO?
12% CO?
12% C02
12% CO,
12% C02
50% excess
air
50% excess
air
50% excess
air
12% C02
12% C02
12% CO,
12% C02
12% C02
12% C02
12% C02
Process
Conditions
>50 TPD
All Others
<200 Ibs/hr
200-1000 Ibs/hr
>1000 Ibs/hr
>200 Ibs/hr
<200 Ibs/hr
Typical of all 43 APCD's
New
Existing
New
Existing
1000 Ib/hr
>3000 Ib/hr
>50 TPD (new)
>50 TPD (existing)
>50 TPD
<50 TPD
Existing before 1/1/72
>2000 Ibs/hr
<2000 Ibs/hr (existing)
>60,000 Ibs/lir
<2000 Ibs/hr (new)
Equivalent
Common
Regulation
gr/scf@12%C02
.11
.21
.3
.2
.1
.09
.2
.3
.3
.1
.15
.08
.24
.21
.021
.09
.11
.08
.1
.2
.21
9
.08
.02
.05
.1
-IB-
-------
TABLE 2-4 (CONTD.)
EMISSION LIMITATIONS FOR
EXISTING MUNICIPAL INCINERATORS
State
IN
IA
KS
KY
LA
ME
MD
MA
MI
MN
MS
MO
MT
NE
Regulation
alue
.4
.7
.2
.35
.3
.2
.1
.2
.08
.2
.2
.03
.1
.3
.3
.2
.1
.2
.1
.2
.3
.3
.2
.1
.2
.1
Units
lbs/1000 Ibs gas
lbs/1000 Ibs gas
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
lbs/1000 Ibs gas
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
Corrected To
50% excess air
50% excess air
12% C02
12% CO,
12% C02
12% C02
12% CO?
12% C02
12% CO,
12% CO,
12% CO,
12% CO,
12% CO,
50% excess air
12% C02
12% C02
12% CO,
12% C02
12% C02
12% C02
12% CO,
12% C02
12% C02
12% CO,
12% C02
12% CO,
Process
Conditions
>1000 Ibs/hr
All others
>1000 Ibs/hr
<1000 Ibs/hr
<200 Ibs/hr
200-20,000 Ibs/hr
>20,000 Ibs/hr
>50 TPD
.<50 TPD
150 TPD
<200 Ibs/hr
200-2000 Ibs/hr
>2000 Ibs/hr
Design capacity
New sources near resid.
areas
^200 Ibs/hr (new)
All others
<200 Ibs/hr
>200 Ibs/hr
New sources
<2000 Ibs/hr
22000 ]bs/hr
Equivalent
Common
Regulation
»r/scf@12%C02
.24
.42
.2
.35
.3
-.2
.1
.2
.08
.2
.2
.03
.1
.18
.3
.2
.1
.2
.1
.2
.3
.3
.2
.1
.2
.1
-19-
-------
TABLE 2-4 (CONTD.)
EMISSION LIMITATIONS FOR
EXISTING MUNICIPAL INCINERATORS
State
NV
NH
NJ
NM
NY
State
City
NC
ND
OH
OK
OR
PA
RI
Regulation
Value
Cal-
culate
.3
.2
.08
.1
.3
3.0
21
130
2.0
15
80
.4
Cal-
culate
.1
.2
Cal-
culate
.3
.2
.1
.1
.16
.08
Units
E - 40 - 7 x 10~5R
gr/scf
gr/scf
gr/scf
gr/scf
Prohibition
Ib/hr
Ib/hr
Ib/hr
Ib/hr
Ib/hr
Ib/hr
Ib/hr
Ibs/hr
Ibs/hr
E = .0252R'67 (R =
lbs/100 Ibs charged
Ibs/hr 7577
E = .01221R' (R
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
gr/scf
Corrected To
R, E - Ib/hr
12% C02
12% C02
12% CO,
12% CO,
bs/hr)
= Ibs/hr)
12% CO,
12% C02
12% CO,
Process
Conditions
>2000 Ibs/hr
<200 Ibs/hr
>200 Ibs/hr (new)
>50 TPD
<100 Ib/hr
@ 1000 Ib/hr
@ 10,000 Ib/hr
@ 100,000 Ib/hr
@ 1,000 Ib/hr
@ 10,000 Ib/hr
@ 100,000 Ib/hr
£22,000 Ibs/hr
>1,000 Ihs/hr
MOO Ibs/hr
<100 Ibs/hr
>100 Ibs/hr
<200 Ibs/hr
>200 Ibs/hr (existing)
>200 Ibs/hr (new)
<2000 Ibs/hr
2:2000 Ibs/hr
Equivalent
Common
Regulation
gr/scf@12%C02
.04
.3
.2
.08
.1
0
.32
.32
.22
.14
.21
.16
.085
.017
.09
.11
.21
.11
.3
.2
.1
.1
.16
.08
-20-
-------
TABLE 2-4 (CONTD.)
EMISSION LIMITATIONS FOR
EXISTING MUNICIPAL INCINERATORS
State
SC
SD
TN
TX
UT
VT
VA
VA
WV
WI
WY
Wash
D.C.
Regulation
Value
.6
.2
.2
.2
.1
Cal-
culate
.08
.1
.14
.1
3.25
5.43
2.72
.15
.2
.3
.5
.6
.2
.08
Units
lbs/106BTU
lbs/100 Ibs charged
% of charging rate
% of charging rate
% of charging rate
E • .048Q'62
gr/scf
lbs/100 Ibs charged
gr/scf
gr/scf
Ibs/hr
Ibs/hr
Ibs/hr
lbs/1000 Ibs gas
lbs/1000 Ibs gas
lbs/1000 Ibs gas
lbs/1000 Ibs gas
lbs/1000 Ibs gas
lbs/100 Ibs charged
gr/scf
Corrected To
E = Ibs/hr
Q = ACFM
12% CO,
12% CO,
7% 0?
12% C02
12% C02
12% C02
12% C02
12% C02
12% C02
Process
Conditions
<200 Ibs/hr
200-2000 Ibs/hr
>2000 Ibs/hr
>1000 ACFM
>50 TPD
<200 Ibs/hr
200-15000 Ibs/hr
>15000 Ibs/hr
>_ 4000 Ibs/hr } built
500-4000 Ibs/hr / after
< 500 Ibs/hr J 4/1/72
> 500 Ibs/hr \ built
< 500 Ibs/hr /before
4/1/72
Equivalent
Common
Regulation
>r/scf(?12%C02
.28
.21
.21
.21
.11
.30
.08
.11
.14
.3
4.4
.04
.01
.08
.11
.16
.26
.32
.21
.08
Note:
A 300 TPD facility, operating 3 shifts/day
was assumed where appropriate
-21-
-------
• 0.94 lbs/100 Ibs refuse
• 0.89 gr/scf @ 50% excess air
» 1.26 grams/Nm3 at 7% C02
On December 23, 1971, standards of performance for municipal in-
cinerators of greater than 50 tons per day charging rate were promul-
gated pursuant to Section 111 of the Clean Air Act. These regulations
applied to all incinerators for which construction or modification had
begun after August 17, 1971, limiting particulate emissions from such
facilities to 0.08 grains/standard cubic foot corrected to 12% C02,
maximum two hour average. The enforcement of this regulation is the
responsibility of the Federal EFA; however, in many cases, they have
delegated the authority to individual states.
-22-
-------
3.0 MUNICIPAL INCINERATION AND AIR POLLUTION
3.'1 Process Description
3.1.1 Combustion
Solid waste incineration, when carried out under the proper combina-
tion of turbulence, time and temperature, is capable of reducing the charge
to a non-combustible residue consisting only of the glass, metal and masonry
materials present in the original charge.
Drying & Ignition
Since most municipal solid waste contains substantial quantities of
both surface and Internal moisture, a drying process is necessary before
igaltlon can occur and the combustion process can proceed. This drying
process continues throughout the entire length of the furnace, but proceeds
at the greatest rate immediately following charging of the solid waste.
Once moisture is removed, the temperature of the substance can be raised
to the ignition point, although the outer surface of a solid may be dried
and ignited before the inner material is dried.
To facilitate drying, some furnace designs use preheated air or in-
corporate reflecting arches to radiate heat stored from the burning of
previously charged material. The first part of the grate system is also
frequently referred to as the drying grate. Ignition takes place as the
solid waste is dried and continues through the furnace. The portion of
the grates where ignition first occurs is often called the ignition grate.
Primary & Secondary Combustion
The incineration combustion process is thought of as occurring in
two overlapping stages - primary combustion and secondary combustion.
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Primary combustion generally refers to the physical-chemical changes
occurring in proximity to the fuel bed and consists of drying, volatili-
zation, and ignition of the solid waste. Secondary combustion refers
to the oxidation of gases and particulate matter released by primary
combustion. To promote secondary combustion, a sufficiently high tem-
perature must be maintained, sufficient air must be supplied, and tur-
bulence or mixing should be imparted to the gas stream. This turbulence
must be intense and must persist long enough to ensure thorough mixing
at the temperatures required for complete combustion.
Combustion Air
In the combustion process, oxygen is needed to complete the chemical
reaction involved in burning. The air necessary to supply the exact
quantity of oxygen required for the chemical reactions is termed stoichio-
metric or theoretical air. Any additional air supplied to the furnace is
termed excess air and Is expressed as a percentage of the theoretical air.
Air that is purposely supplied to the furnace from beneath the grates
is termed underfire air. Overfire air is that air introduced above the
fuel bed; its primary purpose, in addition to supplying oxygen, is to
provide turbulence. Infiltration air is the air that enters the gas
passages through cracks and openings and is frequently Included In the
figure for overfire air.
The proportioning of underfire air and overfire air depends on
incinerator design; very often, however, the best proportions are
determined by trial and error. For most municipal incinerator designs,
underfire air ranges from 40 to 60 percent of the total air. This amount
of underfire air should provide acceptable combustion in the fuel bed and
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adequate grate cooling. In general, as the underfire air is decreased,
Che burning rate Is inhibited; but with increasing underfire air,
particulate emissions are likely to increase.
To supply adequate air for complete combustion and to promote tur-
bulence, a minimum of 50 percent excess air should be provided. Too
much excess air, however, can be detrimental because it lowers furnace
temperatures. In general, refractory furnaces require 150 to 200 percent
excess air, whereas water wall furnaces require only 50 to 100 percent
excess air.
Furnace Temperatures
At the air intake, combustion air may be either at ambient temperature
or preheated, depending on furnace design. Immediately above the burning
waste, the temperature of the gases generally ranges from 2100 to 2500 F,
and for short periods of tine, it may reach 2800 F in localized areas.
When the gases leave the combustion chamber, the temperature should be
between 1400° to 1800° F and the gas temperature entering the stack should
be less than 1000°F. Where induced draft fans, electrostatic precipitators,
and other devices requiring lower gas temperatures are used, the gases will
have to be cooled even further to about 500° to 700° F.
Furnace temperature varies considerably, depending on where it is
measured. The most widely accepted location for measuring and reporting
furnace temperature is near the roof at the exit of the combustion
chamber. At this location, the temperature should be maintained between
1,400 and 1,800° F to ensure that proper combustion has occurred. Most
-25-
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incinerator designs are based on temperatures within this range, however,
in practice, operating temperatures frequently fluctuate by 200 F or more,
sometimes in a matter of minutes. The furnace temperature should be main-
tained at fairly constant levels, preferably in midrange since such op-
eration will accommodate sudden temperature changes.
Regulation of the combustion process through control of furnace
and flue gas temperatures is achieved principally through the use of
excess air, water evaporation, and heat exchange. Of these, the use of
excess air is the most common and, in refractory furnaces, is often
the only method of control. Even when another cooling method is avail-
able, some excess air is still used but primarily for ensuring turbu-
lence and complete combustion.
3.1.2 Furnaces
The combustion process takes place in the furnace of the incinera-
tor, which includes che grates and combustion chambers. There are nu-
merous designs or configurations of furnaces to accomplish combustion,
and, to date, no one design can be considered the best.
Furnaces commonly used for the incineration of municipal solid
waste are the vertical circular furnace, the multicell rectangular fur-
nace, the rectangular furnace, and the rotary kiln furnace. Although
these furnaces vary In configuration, total space required for each is
based on a heat release rate of about 18,000 Btu per cubic foot of furnace
volume per hour, however, heat release rates can vary from 12,500 to 25,000
Btu per cubic foot.
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The vertical circular furnace is usually refractory lined. Solid
waste is charged through a door or lid in the upper part (usually the
ceiling) and drops onto a central cone grate and the surrounding circular
grate (Figure 3-1). Underfire forced air is the primary combustion air
and also serves to cool the grates. As the cone and arms rotate slowly,
the fuel bed is agitated and the residue works to the sides where it is
discharged, manually or mechanically, through a dumping grate on the
periphery of the stationary circular grate. Stoking doors are provided
for manual agitation and assistance in residue dumping if necessary.
Overfire air is usually introduced to the upper portion of the circular
chamber. A secondary combustion chamber is adjacent to the circular
chamber. Many furnaces of this design are in operation today.
. CHARGING lOfff R
Figure 3-1
Vertical Circular Furnace
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The multicell rectangular furnace, also called the mutual assis-
tance furnace, may be refractory lined or water cooled; it contains
two or more cells set side-by-side, and each cell normally has rectangular
grates (Figure 3-2). Solid waste is usually charged through a door in the
top of each cell. Generally, the cells of the furnace have a common sec-
ondary combustion chamber and share a r sidue disposal hopper.
CHAROINO CMUTC
f^\ OVERFI«
I/ AIR INLET
RESIDUE
HOPPIR
Figure 3-2
Multicell Rectangular Furnace
The rectangular furnace is the most common type of recently con-
structed municipal incinerator (Figure 3-3). Several grate systems are
adaptable to this form. Commonly, two or r.ore grates are arranged in
tiers so that the moving solid waste is agitated as it drops from one
level to the next level. Each furnace has only one charging chute.
Secondary combustion is frequently accomplished in the aft end of the
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furnace which is separated from the front half by a curtain wall. This
wall serves to radiate heat energy back towards the charging grate to
promote drying and ignition as well as to increase combustion gas velocity
and the level of turbulence.
\\\\\\\\\\\\\yA^\\\\\\\\\\\\\\NX^SN\\\\\\\\\\\\\\\\\\\\\\\\\\\\
SUPERSTRUCTURE-
Figure 3-3
Rectangular lurnace
h rotary kiln furnace consists of a slowly revolving inclined kiln
that follows a rectangular furnace where drying and partial burning occurs
(Figure 3-4). The partially burned w*3te is fed by the grates into the
kiln where cascading action exposes unburned material for combustion.
Final combustion of the combustible gases and suspended combustible parti-
culate occurs in the mixing chamber beyond the kiln discharge. The residue
falls from the end of the kiln into a quenching trough.
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TO EXPANSION CHAMBER
AND GAS SCRUBBER
XfSIDUE CONVEYORS
Figure 3-4
Rotary Kiln Furnace
3.1.3 Grate Systems
A grate system must transport the solid waste and residue through
the furnace and, at the same time, promote combustion by adequate agita-
tion and passage of underfire air. The degree and methods of agitation
on the grates are important. The abrupt tumbling encountered when
burning solid waste drops from one tier to another will promote combustion.
Abrupt tumbling, however, may contribute to entrainment of excessive
amounts of particulate matter in the gas stream. Continuous gentle agita-
tion promotes combustion and limits particulate entrainment. Combustion
is largely achieved by air passing through the waste bed from under the
grate, but excessive amounts of underfire air contribute to particulate
entrainment. Some inert materials, such as glass bottles and metal cans,
aid combustion by increasing the porosity of the fuel bed. Conversely,
inert materials inhibit combustion if the materials clog the grate opening.
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Mechanical grate systems must withstand high temperatures, thermal shock,
abrasion, wedging, clogging, and heavy loads. Such severe operating con-
ditions can result in misalignment of moving parts, bearing wear, and
warping or cracking of castings.
Ordinarily, the design value for grate loading will be between SO
and 70 pounds per square foot per hour. This design value depends mostly on
the type of solid waste and grate design, but also depends on the other
elements of the furnace. The grate loading is often expressed in Btu's
per square foot per hour. An average rating of 300,000 Btu per square
foot of grate per hour is often used as a design parameter.
Grate systems may be classified by function, such as drying grate,
ignition grate, and combustion grate. Grates for solid waste Incineration
may also be classified by mechanical type. They include traveling, recip-
rocating, oscillating, and reverse reciprocating grates; multiple rotating
drums; rotating cones with arms; and variations or combinations of these
types. In the United States, traveling, reciprocating, rocking, rotary
kiln, and circular grates are most widely used.
Traveling grates are continuous,'belt-like conveyors (Figure 3-5). A
single traveling grate does not promote agitation but two or more grates
at different elevations do provide some agitation as the material drops
from one level to the next.
In reciprocating grate systems, the grate sections are stacked like
overlapping roof shingles (Figure 3-6). Alternate grate sections slide
back and forth while adjacent grate sections remain fixed. Like traveling
grates, reciprocating grates may be arranged in multiple-level series
providing additional agitation as the material drops from one grate to
the next.
-3J-
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Figure 3-5
Traveling Grates
Figure 3-8
Circular Grates
A - Rotating Cone
B - Extended Stoking Arm
(Rabble Arm)
C - Stationary Circular Grate
D - Peripheral Dumping Grate
MOVING
CRATES
-Figure 3-6
Reciprocating Grates
KMMM rOSIDON
Figure 3-7
Rocking Grntos
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Rocking grates are arranged in rows across the width of the furnace,
at right angles to solid waste flow. Alternate rows are mechanically
pivoted or rocked to produce an upward and forward motion, thus advancing
and agitating the solid waste (Figure 3-7). Rocking grates can also be
arranged in series.
The rotary kiln has a solid refractory surface and is commonly
preceded by a reciprocating grate. The slow rotation of the kiln, which
is inclined, causes the solid waste to move forward in a slowly cascading
motion.
The circular grate, in the vertical circular furnace, is commonly
used in combination with a central rotating cone grate with extended
rabble arms that agitate the fuel bed (Figure 3-8).
3.1.It Charging of Solid Waste
Solid waste is charged either continuously or in batches. In the
continuous process, solid waste is fed to the furnace directly through
a rectangular chute that is kept filled at all times to maintain an air
seal. In the batch process, solid waste is fed to the furnace intermit-
tently through a chute, or the furnace may be fed directly by opening
the charging gate and dropping the waste directly from a crane bucket,
front end loader, or bulldozer. A ram can also be used to feed a batch
of material directly on to the grate through an opening in the furnace
wall. Continuous feed minimizes irregularities in the combustion system.
Batch feeding causes fluctuations In the thermal process because of the
non-uniform rate of feeding and intermittent introduction of large quan-
tities of cool air.
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3.1.5 Residue Removal
Residue, or all of the solid material remaining after burning, in-
cludes ash, clinkers, tin cans, glass rock, and unburned organic sub-
stances. Residue removal can be either a continuous operation or an
intermittent batch process. In a continuous feed furnace, the greatest
volume of residue comes off the end of the burning grate; the remainder
comes from siftings and from fly ash. The residue from the grate must
be quenched and removed from the plant.
Batch operated furnaces usually have ash collection and storage
hoppers beneath the grates. Periodically, residue is removed, quenched,
accumulated in a residue hopper, and discharged from the bottom by opening
a watertight gate. The discharge may be placed Into trucks or other con-
tainers for transport to a disposal area. Access to the residue hoppers
is usually by a tunnel beneath the furnace floor. Provisions are generally
made for adequate ventilation and dust removal in this area. Excess quench
water is drained before trucks are loaded, and the residue trucks or con-
tainers are generally watertight. Residue trucks dripping quench water
to the disposal site are unsightly, unsanitary, and they invite complaints
from the community.
In many continuous feed operations, residue is discharged continuously
into a trough or troughs connected to all furnaces. A slow-moving drag
conveyor, submerged in the water-filled trough, continuously removes the
residue. Usually the discharge end of the conveyor is inclined to allow
drainage of excess quench water from the residue before loading into a
holding hopper or directly into trucks. The residue conveyor system
must be ruggedly constructed to withstand h'javy loads and continuous
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use. The residue is highly abrasive, and the quench water is highly
corrosive. Since the residue is discharged to the conveyor below
water, this system has the advantage of maintaining an air seal to
the furnace.
Siftings are the fine materials that fall from the fuel bed through
the grate openings during the drying, ignition, and burning processes.
They consist of ash, small fragments of metal, glass and ceramics,
and unburned or partially burned organic substances. In some designs,
siftings arc collected in troughs and conveyed continuously by sluicing
or mechanical means to a residue collection area. In other designs,
siftings are collected and returned continuously by a conveyor to the
furnace. They may also be removed by the batch method. If siftings
containing highly combustible materials such as oil, plastics, and grease,
accumulate unquenched beneath the grate, they can burn and cause heat
damage to the grates above.
3.1.6 Exhaust Gas Treatment
The burning of solid waste generates heat that expands the volume
of gas. The gas passages, air pollution control devices, and stack must
satisfactorily accommodate this gas. An estimate of the quantities of
gaseous products of combustion can be calculated from the ultimate
analyses of solid waste and knowledge of the amount of combustion air
introduced. Gas velocities must be determined so that gas passages can
be sized to prevent excessive settlement of entrained particles, while
minimizing pressure losses.
To adequately control the combustion process, the draft must be
regulated. Dampers are generally used in both natural draft stacks and
-•V.-
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in stacks employing induced draft fans of constant speed. Adjustable
speed, induced draft fans are also used to control draft and improve
combustion conditions. In addition, induced draft fans are required
on incinerators incorporating high efficiency air pollution control
equipment (precipitators and scrubbers) because of either the high
pressure drop requirements or the need for control of the volume through-
put.
Incinerator stacks provide for the atmospheric dispersion of gases
and particulate matter and as the draft mechanism in the case of natural
draft furnaces. The required height of the stack is a function of ambient
air quality, health effects, Federal Aviation Agency Regulations, archi-
tecture and other constraints.
Water injected into the hot gas stream cools the flue gas through
evaporation of the water and adsorption of heat during superheating of
the water vapor. Although the water vapor adds to the total gas volume
in a manner similar to the addition of excess air, the total of water
vapor and cooled gases is smaller than the original volume of gases.
Some economy may result from reducing this volume of gas to be treated;
however, the cost of water should also be considered.
Heat exchange through the use of water tube walls and boilers, a
well-established European practice, is attracting greater attention in
the United States. A distinct advantage of heat exchangers in cooling
gases is that additional gases or vapors are not added to the gas flow
to reduce temperature and significantly smaller gas volume results. Be-
cause gas volume is greatly reduced, the size of collection devices, fans
and gas passages can be reduced. Heat recovery and utilization can bring
further economies through the sale of steam or the generation of electricity.
u,
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3.2 Environmental Impact
On a nationwide basis, municipal incinerators contribute a very small
portion of the total air pollutants generated by stationary combustion sources
and are responsible for only a fraction of the water pollution resulting
from industrial-type operations. On the other hand, individual facilities can
contribute significantly to environmental degradation, especially in the
urban areas in the northeastern part of the United States, where the majority
of incinerators are located.
Municipal incinerators should not have significant negative impact on
the environment if they: (1) are designed and operated to minimize emissions
of smoke, odors, and unburned organic gases and vapors; (2) are equipped
with air pollution control devices that will ensure compliance with air
pollution emission standards; (3) treat their wastewaters either by neutrali-
zation or sedimentation on-slte or by discharge to a municipal sewage treat-
ment plant to comply with applicable standards; (4) dispose of their residue
in a sanitary landfill; (5) adhere to a litter control program.
3.2.1 Air Pollution - Particulate Matter
Entrained particulate matter is the major air pollutant from the incinera-
tion of solid waste. Although there are also some environmentally detrimental
gases resulting from Incineration, they are not regulated on a national basis
and only nominally regulated on a statewide basis. This Manual addresses it-
self to the emission and control of particulate matter only since it is the
only pollutant presently regulated throughout the U.S.
The quantity and size of particulate emissions leaving an incinerator
varies widely, depending on Ruch factors as the type of refuse being fired,
the method of feeding, operating procedures and completeness of combustion.
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The control of such emissions from incineration begins, however, in the
furnace. Proper design and careful operation will insure that the pollutant
discharge is minimized.
Airflow delivered to the combustion process must be carefully controlled,
as this can have a major effect on the pollutants emitted, both solid and
gaseous. A certain amount of excess air is always required to assure proper
combustion of the refuse and to avoid excessive furnace temperature. Too
much excess air results in high velocities and increased carryover of
particulate as well as a reduction in the furnace temperature to below
that required for complete combustion. Tht proper use of overfire air
can greatly reduce the carryover of unburned combustibles.and dust by
Insuring their complete burnout and when properly aimed, it can knock
fly ash back onto the refuse bed. The proper delivery and quantity of
underfire air can minimize particle entralament while maximizing com-
bustion efficiency. Fly ash carryover from the refuse on the grate will
increase approximately as the square of the air velocity through the
grate. This is, therefore, one factor in limiting the combustion rate
on the grate, as it is easier and less costly to reduce emissions leaving
the furnace than it is to remove them from the stack gas. NO and S0_
emissions are also increased when too much air passes through the furnace.
Plane travel, or the height of the flame above the refuse bed, in-
creases with the combustion rate as well as with the volatile and moisture
contents of the refuse. The furnace must, therefore, be large enough
to permit burnout of this flame either In the primary chamber or In the
secondary chambers. When these are too small, the flame may carry over
into the stack thus resulting in fire haeard and incomplete combustion
with UMilebU'abJe g^eeoMH Bwiasiaup, It IB generally $fefpetkl* p
this flame travel in a vertical direction so that the burnout occurs in
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the primary chamber. This assures more complete combustion and reduced
carryover.
The important properties of the entrained particulate matter, from
the standpoint of its collection are the mass loading, particle size dis-
tribution, specific gravity, electrical resistivity and chemical composition.
Studies C*)of incinerators ranging in size from 50 to 250 tons per day employing
a variety of grate configurations have quantified such parameters. Values
of particulate emissions were found to vary from 10 to over 60 pounds per
ton of solid waste burned. The relationship of these emissions to under-
fire air is shown in Figure 3-9. Particle size distribution and specific
gravity are critical to the performance of most particulate collectors and
essentially determine the level of sophistication required to meet a given
emission limitation. Data on typical particle size distribution, specific
gravity and combustible content of entrained particulate are shown in
Figure 3-10 for three continuous-feed, refractory furnace incinerators.
Because the nature of the waste charged and furnace conditions have a
material effect on such determinations, caution must be exercised in
generalizing from this information.
• .'
ito TPO MCKim wart
MO TPO TWVIIWO OMTC
150 IPO RtCIP*OC*TIM OMTf
•0 TPO MTCH PICO
MO in iKmi.ua w«Ti
Physical analysis
Specific gravity
(gB/CC)
Bulk density (Ib/cf)
Loss of ignition at
750 C (X)
Size distribution
(Z by weight)
<2w
<4M
<6y
<8p
<10w
«15w
<20p
<30|i
1
(250 TPD)
2.65
-
18.5
13.5
16.0
19.0
21.0
23.0
25.0
27.5
30.0
Installation
2
(250 TPD)
2.70
30.87
8.15
14.6
19.2
22.3
24.8
26.8
31.1
34.6
40.4
3
(120 TPD)
3.77
9.4
30.4
23.5
30.0
33.7
36.3
38.1
42.1
45.0
50.0
uMturmc urn IKTM/M n OMTII
Figure 3-9
Entrained Particulate Emissions
Figure 3-10
Properties of Partlculates
Leaving Furnace
-39-
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Electrical resistivity of the fly ash is the property of prime Interest
when electrostatic precipitators are considered for particulate collection.
High resistivity participates cause dit turbances in electrical operation
that reduce collection rates. In general, collection of particulates with
higher resistivities requires larger and more expensive precipitators. Wet
scrubbers or fabric filters may be preferred if resistivity is very high.
Very low resistivities are also troublesome, but can be handled in properly
designed precipitators. When the resistivity is low, the dust readily loses
Its charge to the collecting electrode; this can cause the particle, par-
ticularly if it is large, to be reentrained in the gas stream.
The optimum resistivity range for efficient operation of an electro-
static precipitator lies between 10 and 10 ohm-cm. Thus, to select
the mosu suitable air pollution equipment, the resistivity of the fly ash
must be known. Figure 3-11 presents tjpical resistivity-temperature curves
0 100 300 bOO 7OO
O Installation 1
D Installation 2
A. Installation 3
II MCI MAI I Kl (II
Figure 3-11
Typical Resistivity-Temperature Curves
-40-
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of entrained particulates leaving larg« , continuous feed refractory furnace
incinerators.
3.2.2 Air Pollution - Gaseous Emissions
Both nitrogen oxide and sulfur oxide emissions occur in solid waste
incineration, but the amounts per ton <>f fuel burned are several orders of
magnitude below those involved in the combustion of fossil fuel. Solid
waste is inherently a "clean fuel" from the standpoint of sulfur content,
with a value of about 0.2 percent by weight as compared to most coals and
residual oils used today, which range from about 1 to 3 percent sulfur.
Further, there is evidence to suggest that for incinerators, most of the
sulfur is retained in the ash rather than as oxides in the stack. Thus,
Sulfur oxide emissions from solid waste incineration generally are well
below even the most stringent present or anticipated restrictions. It
is .not likely that NO emissions will be regulated in the immediate future
since emission levels are only one-tenth of those from fossil fuel com-
bustion.
Some concern has been expressed about emissions of hydrogen chloride
(HCL) that might occur as a result of incineration of certain plastics -
namely polyvinyl chloride. Hydrogen chloride is irritating to the eyes and
respiratory system, and if the amounts released during incineration were
great enough, a health problem would exist. If hydrogen chloride emissions
become a problem, control will be necessary, but since this gas is highly
soluble in water, it can be effectively removed by water scrubbers.
3.2.3 Water Pollution
Almost without exception, all incinerator plants utilize water for
residue quenching. In addition, many plants use water for wet bottom
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expansion chambers, for cooling charging chutes, for fly ash sluicing,
for residue conveying, and for air pollution control. The quantity of
water required depends on plant design, on how well the system is operated,
and whether water is recirculated. Total water requirements without re-
circulation, for a 300 ton-per—day plant with two 150 ton continuous feed
furnaces have been reported ^'to be about 2,000 gallons per ton of solid
waste charged. Quenching and conveying used 1,800 gallons and the wetted
baffle dust collection system used 200 gallons. The study cited indicated
that the use of a recirculation, clarification, and neutralizing system
reduced the total water needed from 2,020 to 575 gallons per ton of solid
waste.
Because of extreme variation in incinerator design, generalizing on
water requirements is of only limited value. A rule of thumb, however,
is that residue quenching and ash conveying at most plants requires 1,000
to 2,000 gallons of water per ton of solid waste processed. With water treat-
ment and recirculation, total water consumption can often be reduced 50
to 80 percent.
Incineration process water can contain suspended solids, Inorganic
materials in solution, and organic materials that contribute to biochemical
and chemical oxygen demand. A limited study' 'of incinerator wastewaters
from a 50-ton-per-day, batch feed incinerator and from a 300-ton-per-day
continuous feed municipal incinerator showed the presence of bacteria in
the waste water from both operations. The cited studies indicated that
incinerator process waters can be contaminated and, therefore, should
not be discharged indiscriminately to streams or other open bodies of
water. The most straightforward control IB the discharge of these waters
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to a sanitary sewer for subsequent handling in a central treatment plant.
If the waste process waters cannot be ultimately discharged to a sanitary
sewer, the incinerator plant should be equipped with suitable means for
primary clarification, pH adjustment, and if necessary, biological treat-
ment to meet local standards.
Water used for dust control and for periodic washdown to control
insects and rodents is a potential pollutant. Current practice makes
no attempt to integrate these waters into in-plant water treatment facil-
ities, but allows drainage to surface waters or sanitary sewers. The
pollution is considered minimal compared with that of other process waters.
Even so, they should be conveyed to an onsite or offsite treatment pro-
cess.
Incinerator residue is permeable and may contain water soluble in-
organic compounds! If water moves through the deposit of residue,
leaching can occur. Pollution can result if the leachate water moves
through the underlying soil and enters the groundwater. Surface water
can also become contaminated where the leachate moves laterally through
the surrounding soil. In many cases, therefore, only sanitary landfill
methods can be employed to dispose of incinerator residue.
Where there is no danger of water pollution, residue may be used as
a fill material if the residue does not attract Insects or rodents.
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4.0 AIR POLLUTION CONTROL TECHNOLOGY
The emphasis on controlling air pollutants from municipal incinerators
has beun primarily on the reduction of particulate emissions. Over the years,
improved combustion in modern municipal incinerators has reduced particulate
emissions and smoke, but uncontrolled particulate emissions are still sig-
nificant, and must be controlled to meet current emission and air quality
standards. This section will discuss particulate emission control technology
applicable to municipal incinerators. Control of gaseous pollutant emissions
will not be considered specifically.
A.I Evolution of Particulate Controls
4.1.1 Settling Chamber
The most rudimentary form of particulate collection system is the settling
chamber (also called an expansion or subsidence chamber). The settling chamber
is basically an enlargement in the incinerator exhaust ductwork that provides
for a decrease in gas velocity and allows the larger particles to settle out.
Settling chambers can be of dry or wet bottom construction. With the excep-
tion of a few units with sprays or spray-baffle systems, settling chambers
represented the state-of-the-art in the early 1950's. Collection efficiencies
for settling chambers are well below 50 percent.
At about this same time, some attempts were made to further reduce partic-
ulate emissions by installing checkers at the outlet of settling chambers to
provide some degree of dry particulate Impingement. In other cases, settling
chambers were converted to water spray chambers to create a rudimentary scrub-
ber. Such modifications provided only limited collection efficiency improve-
ment over simple settling chambers.
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In 1949, the American Society of Mechanical Engineers (ASME) Issued a
Model Ordinance that limited particulate emissions from combustion sources
to 0.85 lb/1,000 Ib of flue gas at 50% excess air. An uncontrolled incinera-
*
tor emits about 30 pounds of particulate per ton of refuse charged, which
would be equivalent to 2,7 lb/1,000 Ib flue gas at 50% excess air. There-
fore, application of the ASME model ordinance required an overall particulate
85
collection efficiency of at least 100 (1 - •=—=• ) = 69%. For an incinerator
£ i /
already fitted with a settling chamber and spray system, the additional col-
lect icn efficiency needed to conform to this standard would have been only
about 33%.
A.1.2 Wetted Baffle
During the late 1950's, the ASME-recommended emission limitation was
incorjorated into many local ordinances and applied to municipal Incinerators.
One method used to meet this standard was the installation of flooded or spray-
wetted baffles in the incinerator outlet to provide wetted impingement sur-
faces for collection and removal of particles. These devices offered little
resistance to the flow of gases (0.3 to 0.6 in. water gauge pressure drop)
and a natural draft stack could still be used. Collection efficiencies for
such cevices vary widely, but are generally around 50 percent at best.
4.1.3 Mechanical Collector
Another approach used to meet the ASME standards was the installation of
mechanical collectors or cyclones. This method circumvented the problem of
contaminated water streams, but cyclones, because of their appreciable
*Thi8 estimate Is based on AP-42j5'If the Incinerator already has a
settling chamber and water spray system, emissions would be about one half
of this value.
-45-
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pressure drop (2 to 4 in, water gauge), required the use of an induced draft
(ID) fan. Furthermore, cooling of the exhaust gas by air dilution or evapora-
tion was required to protect the cyclones and ID fan from excessive tempera-
tures. Cyclone installations were of two general types: batteries of rela-
tively large (24 to 40 inch diameter) cyclones with involute or scroll type
entry connections and batteries of a large number of small (9 to 12 inch
diameter) cyclones with spinners or turning vane entries. Of the two types,
the large diameter units were the more successful. Tie small diameter units,
while giving generally higher collection efficiencies, tended to plug and
wear rapidly because of smaller gas passages and higher internal velocities.
Collection efficiencies for cyclones are in the range of 60 to 80 percent.
4.1.4 Wet Scrubber
During the late 50's and early 60's many municipalities were requiring
more stringent particulate emission control based upon experience and legisla-
tion from air pollution control agencies on the west coast. For example, the
Los Angeles County Air Pollution Control District limited "Combustion Contam-
inants" to 0.3 gr/scf at 12% C02 or about 5.6 Ib/ton of refuse which is about
0.6 of the ASME required value. To meet such standards, particulate emission
controls for a completely uncontrolled municipal incinerator (30 Ib/ton of
refuse) would be of the order of 100 (1 - -r^- ) = 82%. Incinerators with
settling chambers and sprays (14 Ib/ton of refuse) would require 100 (1 -
|j£) •= 60% additional control.
To meet these more stringent standards, scrubbers of various designs were
used to further reduce particulate emissions. Four basic scrubbing concepts
evolved:
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1. Multiple wetted impingement baffles.
2, Submerged entry of gases,
3. Spray wetted-wall cyclones.
4. Venturl or orifice scrubber.
The first three configurations are considered moderate to low pressure
drop scrubbers (generally less than 10 in. water gauge). Since pressure drop
or energy input into the scrubbing mechanism determines collection efficiency,
such units are capable of only moderate collection efficiency (80 to 90 per-
cent at best). Because of the high velocities possible in venturi and ori-
fice scrubbers, such designs can be made to operate over a wide range of
pressure drops and collection efficiencies. To meet current, tight restric-
tions on incinerator emissions, scrubbers with pressure drops exceeding 15
in. water gauge and collection efficiencies above 95% are required. Regard-
less of the collection efficiency, all scrubbers have the common problem of
generating wastewater that must be disposed of.
The next section covering high efficiency partlculate control devices
will discuss high energy scrubbers in greater detail, together with elec-
trostatic precipitators and fabric filters.
4.2 High Efficiency Control Devices
The degree of emission control needed for municipal incinerators to
meet present and proposed emission standards requires high efficiency collector
systems. The New Source Performance Standard (NSFS) for municipal incinerators
may be applied to existing municipal incinerators by some local agencies as
a mears of further upgrading incinerators. This standard would limit emis-
sions to 0.08 gr/scf at 12% C02 and would be roughly equivalent to 1.5 lb/
ton of refuse. Collection efficiencies for a completely uncontrolled inciner-
ator (30 Ib/ton of refuao) would nacd to i>e at least 100 (1 - •—•) - 951 while
-47-
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an incinerator with a settling chamber and sprays (14 Ib/tc.i of refuse)
would need 100 (1 - jj~- ) = 89* additional control.
Therefore, to upgrade existing incinerators to current and expected
standards, control equipment that can meet at least 90% particulate control is
required. Those municipalities deciding to upgrade existing incinerators would
be prudent to specify control equipment of at least 95% to 99% efficiency to
make certain that the control system can adequately handle changes in char-
acter of waste and can meet even tighter emission standards should they be
imposed. To meet such a requirement, there are only three categories of
control technology currently available that could be considered. They will
be discussed In the following sections.
4.2.1 High Energy Scrubbers
Scrubbers capable of collecting 90 to 99% of the weight of particulate
matter emitted from a municipal incinerator must be able to operate at pres-
sure drops between about 10 and 25 in. water gauge. Pressure drop, or energy
input is the most important scrubber operating variable in determining col-
lection efficiency. The most successful high efficiency scrubber design is
the venturi scrubber, a schematic diagram of which is presented in Figure 4-1.
In this device it is possible to obtain high velocities and a wide range of
water rates within the venturi contacting section. Water rates are generally
in the range of 5 to 15 gal/1,000 cubic feet of flue gas.
In contrast to impingement scrubbers where the partlculates in the hot
gases are impinged on a wetted surface, the venturi scrubber accelerates
gases and scrubbing liquid through a venturi section producing fine liquid
droplets which, because of the extremely turbulent conditions, impact di-
rectly with partlculates. The "enlarged" wet particulates thus formed can
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AIR
INLET
WATER
INLET
VENTURI
AIR
•} OUTLET
CYCLONIC
MIST ELIMINATION
SECTION
WATER
OUTLET
Figure 4-1
Schematic Diagram of Gas Actuated Venturi Scrubber
with Cyclonic Mist Eliminator
then be removed easily in a cyclonic separator. This cycl mic separator
is often fitted with water sprays to keep the side walls clean, and to
further reduce the temperature of the exhaust gases. A mist eliminator
is usually required to prevent loss of liquid droplets to '.he atmosphere.
Special high pressure fans are required for operating high efficiency
venturi scrubbers.
ifigure 4-2 shows a general relationship between efficiency and pressure
drop used for the analysis of venturi scrubbers presented in this Manual.
It is not specific to any particular installation or mechanical configuration
and as such should not be used to determine compliance or erroneous conclusions
could be reached. The information presented evolves from data(°' on fine
particles and actual measured collection efficiencies on municipal incinerators.
-49-
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100 -
X • actual data from tcubberi on municipal 3
Incinerators
A • predicted performance of venturi scrubber on fine
particles (<5;i)
B - one manufacturer's claimed performance of
venturi scrubber on 1 -ft particles
I
0 10 20 30
Scrubber pressure drop, i i. H20
Figure 4-2
Relationship between efficiency and pressure drop
In Venturi Scrubbers
The simplicity In the design of a venturi scrubber permits the use of
a water-flooded wet-dry junction (the point where hot gases first meet water)
which prevents many of the plugging problems inherent in other scrubber de-
signs (e.g., wetted perforated plates, cyclones, impingement plates, plus
packed towers and spray systems).
Because of the high velocities in the venturi throat and the corrosive
and erosive environment, this part of the system Is often lined with a refrac-
tory material such as silicon carbide. In addition, venturi scrubbers can
be built with variable-area throats to permit operation at constant pressure
drop over a range of flow rates.
The flooded disc scrubber can be used in many of the same applications
as a venturi scrubber. This Is basically a variable orifice scrubber which
Is simple in construction, provides a flushed wet-dry junction, can operate
at constant pressure drop over a wide range of flows, end can provide the
same high collection efficiencies of which the vcnturl scrubber is capable.
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Such deylces may be considered In various municipal Incinerator upgrading
programs.
Aside from the high energy requirements, the principal disadvantages
of high efficiency scrubbers are serious corrosion problems, and the need
for a liquid waste treatment system. Corrosion problems are solved by use
of special construction materials, and pH control. At a water rate of
10 gal/1,000 cfm, a venturl scrubber on a 300 T/day Incinerator would re-
quire about 1,000 gpm of water. Water recirculatlon will of course be re-
quired. In the scrubbing process the water becomes highly acidic and an
alkaline material (NaOH, CaO, etc.) must be added to the recirculated water
to minimize corrosion. Slag dump water is often used for at least a part
of this pH control since well burned out incinerator ash produces an alkaline
reaction In water.
4.2.2 Electrostatic Preclpitators
The operation of an electrostatic precipitator depends upon three sequen-
tial events:
1. Charging of the particles in a corona discharge.
2. Migration of the charged particles in an electric field to
and retention by a grounded collection electrode in the
form of flat plates or a metal shell.
3. Removal of collected particles from the collector plates
by rapping to dislodge the particles allowing them to
fall into a hopper, or by flushing the collection electrode
with water.
The large scale precipitators used for cleaning process or combustion
emissions are single stage, i.e., the discharge and collection process
take place in the same part of the precipitator. Figure 4-3 is a schematic
of a typical wire and plate type precipitator. Figure 4-4 is a cut-away
diagram of a typical precipitator.
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. Gdtactmt Elmrodt
\
0000
\_
Chvging Etnoot
Figure 4-3
Schematic Drawing of Electrode Arrangement
in a Single-Stage Electrostatic Precipitator
T«i-
Rt
BUi OUCT
INSULATOR COMPARTMENT.
ROOF
^DISCHARGE CLtCTROOE
[MD
RAPPER INSULATOR
HIGH-VOLTAGE SYSTEM
SUPPORT INSULATCC
—S)D£
DOW?
Figure
Cut-Away View of an Electrostatic Precipitator^7'
-52-
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The charging electrodes, or discharge wires are usually energized
with negative polarity by means of a rectified high voltage. The voltage
gradient In the vicinity of the discharge wire exceeds the breakdown
potential for the gases being treated, and an ionized region or corona
discharge Is formed around the wire. The negatively charge:' ions thus
formed effectively fill the space between the plates and dust particles
entering the channel formed by the collection plates receive a negative
charge. The particles then migrate towards the collector plates under
the influence of the electric field. Particles coming in contact with
the collector plates give up their charge and are held on the plates
until removed by periodic rapping.
The electrical properties of the particles and the moisture content
and temperature of the gas stream affect precipitator operation. Particles
of high resistivity lose their charge very slowly. This can cause accumula-
tions of charge on the collected material and a considerable voltage dif-
ference between the surface of collected materials and the collector plates.
Under these conditions, arcing may occur within the collected particle layer
causing reentrainment of particles and poor precipitator performance. The
resistivity of particles is temperature dependent and moisture in the gas
stream tends to lower resistivity (make the surface of the particles more
conductive). When evaporative cooling is used to cool incinerator gases
to the optimum temperature range for a precipitator (400-600°F), the
moisture added lowers particle resistivity and tends to produce stable
precipitator operation. When exhaust gas cooling is achieved by air
dilution or a waste heat boiler, and the incinerator emits well burned out
particles, the particles may have high resistivity. Under these condi-
tions, it may be necessary to add some moisture to the exhaust gases to
achieve stable precipitator performance.
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When poor combustion conditions prevail in a municipal incinerator,
the particulate matter will have a large carbonaceous component that is
highly conductive. In this situation the charge on the particle leaks off
too rapidly upon reaching the collecting plate, and the particles do not
adhere to the plate and are free to be reentrained as neutral particles.
Frecipitator collection efficiency is related to collection plate
area, volume flow rate and particle migration velocity in accordance with
the following relationship known as the Deutsch equation:
n „ L
where
A ** collecting plate area
V • volume rate
W = particle migration velocity.
The migration velocity term is related to the strengths of the charging
and collecting fields, particle diameter and gas viscosity. Assuming all
variables except plate area are constant, a precipitator capable of collec-
ting 95 percent of all particulate matter would have to be increased in plate
area by about 50 percent to meet a 99 percent collection efficiency. Rela-
tive plate area is a rough indication of relative capital cost for precipi-
tator s.
Precipitators are classed as high efficiency devices, usually operating
in the range from 95 percent to greater than 99 percent. Operating costs
tend to be relatively low because of the low power requirements. Pressure
drops across precipitators are usually less than 1 in. water gauge. Since
particulate matter is collected dry, the problems of a wet scrubber water
recirculation and cleanup system are not present.
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The design of an electrostatic precipitator is based on many factors
dealing not only with the gas stream and particulate matter characteristics
but also on the operation and requirements of the particular installation.
Table A-l lists the typical ranges of the major design parameters for
incinerator applications.
Table 4-2 gives a partial listing of electrostatic precipitator in-
stallations on municipal incinerators in the U.S. and Canada. The major
design parameters are included for comparison purposes.
Plate Spacing
Velocity through Precipitator
Vertical Height of Plates
Horizontal Length of Plates
Applied Voltage
Gas Temperature
Gas Residence Time in Precipitator
Draft Loss
Fields (electrical stages) in Direction
of Gas Flow
Total Power for Precipitator
Collection Area
Efficiency
Gas Flow per Precipitator
Migration Velocity
20-30 en (8-12 in.)
0.9-1.8 m/sec (3-6 ft/sec)
3.6-10 in (12-48 ft)
'0.5-1.5 x height
30,000-80,000 volts
177-343CC (350-650°F)
3-6 sec
3-20 mm water (0.1-0.8 in.)
1-4
7-35 KW per m'/min (0.2-1 KW/1000
ACFM)
400-1000 m2 per 1000 m3/min
(122-305 ft2/1000 ACFM)
93-99*
850-8500 m3/min (30,000-300,000
ACFM)
6-12 cm/sec (0.2-0.4 ft/sec)
Aspect ratio = [total horizontal length (depth) of collection plates] *
(height of collection plates) <• 0.5-1.5
Mean average effective migration velocity of a particle toward the collection
electrode. Sometimes called precipitation rate or drift velocity.
Table 4-1
Typical Electrostatic Precipitator Design Parameters
for Incinerator Applications'6^
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rum
Montreal
Stanford
Stanford
Stanford
(II Brooklyn
So. Shori, V.I.
Dade City. Fin.
Chicago. KU
Rralntree, Maaa.
BaaUton, Ont.
Washington. D.C.
Eaatnan Kodak
Barrlaburn, Pa.
Capacity
TPD
4 x 100
1 x 220
1 « 360
1 « ISO
1 « 2SO
1 « 230
1 « 300
4 » 400
2 x 120
2 x 300
6 x 2SO
1 x 300
2 x ]60
Furnace
Type
Ml
Special R
R
I
R
R
R
Ml
Ml
Ml
R
Ml
W
Co Flow
ACFM
112.000
160.000
221.000
73.000
131.000
136,000
286.000
110.000
32.000
81,000
130.800
101.300
100.000
Caa
Flow
•P
33«
600
600
600
550
600
570
450
600
585
550
623
410
Caa
Velocity
FFS
3.1
6.0
3.6
3.7
4.4
3.3
3.9
2.9
3.1
3.5
4.1
3.4
3.3
R*aldence
Tina
.ee
1.3
3.3
5.0
4.»
3.2
3.3
4.0
4.6
4.3
3.4
3.1
3.5
5.1
Plata Area
SCPH/ft'
6.2
6.6
4.5
4.6
6.7
6.8
3.7
3.5
5.3
3.9
4.9
3.8
3.0
Input
RVA
35
37
225
75
47
33
48
40
19
70
77
106
40
Proeaure
Drop In
H,0 MUG
0.3
0.5
0.5
0.3
2.3
0.3
0.4
0.2
0.4
0.5
0.4
-
0.2
Efficiency
we X
95.0
«.o
95.0
95.0
94.)
95.0
95.6
96.9
93.0
98.5
95.0
97.3
96.8
*R • refractory-lined; WW - watarvall
ROTE l Except for capacity, data refer to dealgn paruatera for one preclpltator; aevertl nay ezlet
Table 4-2
Partial Listing of Electrostatic Preclpltator Installations
4.2.3 Fabric Filters
The fabric filter or baghouse, when properly designed and applied to
the control of participate natter Is considered to be the most efficient of
all particulate control systems. While the basic removal of particulates
by filtration seems simple, since it is analogous to a household vacuum
cleaner, the mechanism of removal is quite complex and inadequately under-
stood. The removal mechanism consists of elements of direct sieving, im-
pingement, diffusion and electrostatic attraction.
While baghouses can take many forms, a typical design that might be
considered for application to a municipal incinerator, would consist of a
multiplicity of fabric bags closed at the top end with the bottom end connec-
ted to sleeves on a tube sheet.
Figure 4-5 Is a diagram of a typical baghouse. Particulate-laden gases
enter through the bottom propelled by a forced draft or induced draft fan.
The baghouse is sectionalized such that one section can be isolated and the
collected particles removed from the inside of the bags by shaking, collapsing,
sonic blast or other methods. Dislodged particles are collected in a hopper.
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TOT ALLY ENCLOSED
FAN COOLED SHAKEN
MOTOR EXPLOSION
PROOF OPTIONAL
PUSHROD
BAG SUPPORT
MEMBERS
POSITIVE BAG TENSIONING
Figure 4-5
Filter Baghouse with Mechanical
!..n order to use a baghouse installation to control municipal incin-
erator particulate emissions, exhaust gas temperatures must be maintained
at less than 550 F - the upper limit of glass fiber baps. Other than one
experimental unit, there have been no successful application;; of baghouses
to municipal incinerators. The principal reason is the difficulty of
controlling the temperature and humidity in the gas to be treated. High
temperature excursions will set a baghouse on fire, and low temperatures
coupled with high moisture content will "blind" the bags, i.e., encrust
them with a hard, hygroscopic deposit that cannot be dislodged short of
removing the bags for washing or replacement. It is highly unlikely that
a baghouse would be used to upgrade particulate control efficiency for
an existing incinerator.
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5.0 FIELD INSPECTION TECHNIQUES
Enforcement of emission standards for municipal incinerators must
involve periodic inspections to ascertain the status of compliance on
a continuing basis. An initial incinerator/emission control system in-
spection should precede any official compliance test program employing
acceptable stack sampling. The purpose of this initial source inspection
is to gather necessary pre-test information, to familiarize the inspector
with the installation, operational and record keeping practices, to get
to know the personnel and, if possible, to initiate certain procedures
which will assist in future inspections. This inspection should
follow a prescribed procedure with propei documentation as provided by
a checklist.
The Inspector should also be present during the official compliance
tests to assure that representative opera :ing conditions are maintained
and that an acceptable operational and record-keeping practice has been
properly established. Documentation of this activity should also be pro-
vided through a checklist.
Subsequent inspection visits should be scheduled and carried out
on a regular basis. During such visits, the inspector should be pre-
pared with an additional check-list which reflects the base-line infor-
mation developed from the initial inspection and compliance test. Com-
parison of observed parameters with this baseline Information, and in-
spection of records accumulated during tie intervening period will
allow the Inspector to develop Judgements as to potential changes in
the compliance status and emission levels.
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Aside from providing legally valid documentation and representing
sound practice in any evaluation of a complex technical process, check-
lists can assure a consistency of approach from Inspection to inspection.
This Is particularly critical in that the same Inspector will not always
be available for visits to the same installation. Accordingly, the
balance of this Manual section will be largely devoted to the presentation
and discussion of the use of the inspection checklists. Three such lists
will be described:
(i Initial source inspection
o Compliance test evaluation
o Periodic compliance inspection
Certain general technical considerations will first be discussed to
aid inspection personnel in understanding the influence of process and
control equipment parameters and their interaction on particulate matter
emissions. Also, a discussion will be provided regarding process and
control equipment instrumentation generally available, and its typical
use. A similar discussion will be provided on record keeping practices.
5.1 Technical Considerations
5.1.1 Process Evaluation
Municipal incineration, as practiced in existing refractory-walled
furnaces, many of which are more than ten years old, represents possibly
one of the least sophisticated combustion processes in use today. Con-
sequently, it is one of the most difficult applications' for particulate
matter emission controls. The performance of incinerator air pollution
control equipment is strongly influenced by any number of variables of
system operation - many of which are unpredictable. If any of these
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parameters deviate significantly from the conditions for which the control
equipment was designed, emission standards may be exceeded, even in the
case of the most sophisticated equipment such as electrostatic preclpitators
and high energy scrubbers.
The following are considered the most important operating parameters
influencing particulate emissions:
o refuse composition
o refuse feed rate
o combustion air supply practice
o furnace temperature
o furnace draft
o gas cooling system performance
o general physical condition of installation
Refuse Composit-'on
The heterogeneity of municipal refuse is well-known. Certain seasonal
aspects can be predicted, and if an incinerator serves a fairly unchanging
community, variations can be relatively minor. However, many unpredict-
able occurrences must be dealt with. For example, wet refuse when in-
troduced into the incinerator, can cause depressed furnace temperatures,
grate plugging, and uneven/improper airflow distribution resulting in
poor or incomplete combustion and smoke. Large quantities of industrial
or commercial wastes can cause excursions of furnace temperature, generally
upward due to the unusually high heat content of certain components of the
waste especially plastics. Often this is accompanied by the evolution
of heavy smoke and particulate entrainment resulting from excessive
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turbulence over the burning bed. Generally, the operators' best remedy
to the sudden arrival of such high BTU waste Is to be aware of its
presence and to adjust the system rationally either by reducing the
burning rate, or by Judicious mixing with other less potent waste.
Refuse Feed Pate
Municipal incinerators generally operate most effectively at a fixed
burning rate. In most cases, deviation from this optimum rate, which is
usual]y established over a long period of experimentation, results in
conditions which promote increased particulate matter emissions. The
more consistent and continuous the burning rate, the more trouble-free
the o]eration of pollution control equipment. For this reason, batch
type furnaces are far more difficult to control than continuously fed
systems. Thus, non steady operation should be avoided, and control of
changing refuse conditions is best effected by judicious mixing in the
refuse pit.
Start up and occasionally shutdown or malfunction can promote greater
than normal emissions of particulate matter. Start up must be accomplished
slowly to protect refractory surfaces and grate components, and furnace
temperatures must be intentionally controlled below the levels required
for optimum combustion. Usually, the increased emissions are not notice-
able since the incinerator is operating at a fraction of its full burning
rate. The emissions can be increased on a weight per unit gas volume
basis, but may be significantly lower than normal conditions, on a pound
per hour basis. Shutdowns or malfunctions requiring shutdown are less
likely to Increase emissions since refuse charging is terminated and
furnace temperatures are maintained by heat stored in the mass of the
furnace refractory. The operator must adjust the combustion airflow
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downward, however, as the refuse burns down, or else high rir input will
quench the furnace temperature, promoting smoking and increased emissions.
Combustion Air Supply Practice
Combustion air is generally supplied from under the grate supporting
the burning refuse in the form of underfire air, and above the grate in
the form of overfire air. Both forms of air supply are extremely impor-
tant to successful incinerator operation, however, underfire air rate
is most associated with particulate matter emissions. Excessive under-
fire air supply usually results in particulate matter being lifted from
the bed and entrained in the gas stream.
Excess air, representing the combustion air supplied to the burning
process in excess of theoretical air, is generally the only parameter
available to the operator to control furnace temperature, other than the
burning rate. Additional air will quench the combustion gases and reduce
temperature; reduced air supply would have the opposite effect. Depending
on the nature of the refuse, the effects may reverse, however, with added
air raising temperature and vice versa due to localized stoichiometric
burning. Furnace excess air levels are generally maintained in the 100 -
200% range. These.levels usually increase substantially at the emission
discharge point due to air infiltration between the furnace and the stack.
Values at the discharge could range from 350% to as high as 600% in poorly
maintained or old units.
Furnace Temperature
Furnace exit gas temperature is one of the few operational para-
meters available to the incinerator operator which provides a "real-
time" measure of the effectiveness of the process. In most installations
the ga« temperature is recorded continuously on charts, giving an operating
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history if the Instrument and recorder are properly maintained. The
location of the furnace exit gas temperature sensor varies, but gener-
ally, the thermocouple is found either at the discharge end of the
secondary combustion chamber or just inside the entrance of the furnace
exit duct. The thermocouple should be shielded to prevent flame radi-
ation effects from biasine the gas temperature reading.
Tne variability in municipal refuse heatine value and moisture con-
tent causes fluctuations in the combustion process, which are reflected
most directly in variations in furnace exit gas temperature. The fre-
quency and extent of such fluctuations can be a relative measure of how
well the system is performing with respect to particulate matter emissions.
Generally if the temperature is maintained between 1400°F and 1800°F, the
operation can be considered satisfactory. Frequent and extensive excursions
beyond these extremes can be expected to increase emissions, and should be
avoided by operator intervention, either through combustion air adjust-
ments, changes in burning rate, or refuse mixing.
Furnace Draft
Proper furnace draft is established through a balance of the air-
flows provided by the induced draft and combustion air fans. The result
of th;.s balance maintains the combustion chamber under slightly negative
pressure (approximately 0.2 inches water column). This condition pre-
vents the loss of combustion products from the furnace enclosure to the
incinerator building (and consequently to the outside as fugitive emissions)
by ensuring that all leakage is inward. If an incinerator furnace begins
to exhibit "puffing" of combustion products from the futnace enclosure, the
furnace draft is in all likelihood not being properly maintained. This
can be Indicative of poor combustion, generally attributable to an excessive
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charging or burning rate. The exhaust gas system is incapable of removing
the combustion gases and only a reduction in the burning rate can restore
a balanced draft.
GOB Cooling System Performance
The gas cooling system is designed to condition the furnace exhaust
gases prior to entering the emission control components. Generally, water
is sprayed into the hot gases to effect cooling by evaporation. In most
existing systems the method of introduction of the water and the time
allowed for evaporation to be completed are not adequate, and unevaporated
water which drains to the bottom of the cooling chamber must be collected
and either discarded or recirculated. This water will contain solid
material which should be removed prior to recirculation. Recirculation,
if not: properly controlled, can cause a re-entrainment of particulate
matter into the gas stream when the water is evaporated. The performance
of the gas cooling system is critical to the performance of the emission
control equipment, especially in the case of electrostatic precipitators,
which cannot tolerate the carryover of liquid water droplets or excessive
temperatures. Poor temperature control can adversely effect fly ash re-
sistivity which has a critical influence on precipitator performance. Bag
filter systems, although rarely used in incinerators, have an even narrower
acceptable temperature range. Scrubber systems are more tolerant of gas
cooling system aberrations, since further cooling to saturation is in-
volved. Poor temperature control characteristics can be attributed to
malfunctioning spray systems due to plugging, corrosion, etc. The plugging
can be the direct result of Improper recirculation and malfunctions of the
wastevater (solids removal) system.
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General Physical Condition of the Installation
The general physical condition of the incinerator installation can
act as a yardstick by which an inspector can judge the probable per-
formance of pollution control equipment. Poor housekeeping, leaks,
corrosion, plugging, excessive temperature, etc. related to the burning
system and gas handling components, could be an indication of potential
problems with the pollution control equipment as well. Generally, a
lack of concern or control over the major components cf the system ex-
tends to the pollution control equipment components which are at least
as complex and demanding of attention. •
5.1.2 Pollution Control Equipment Evaluation
The inspector must be capable of evaluating the performance of a wide
range of devices serving as pollution control equipment. These devices
can range from simple settling chambers to complex electrostatic precipitator
or scrubbing systems. Many of these control systems cannot meet specified
emission limitations, others are of questionable perfcrmance and yet
others do a superb job in meeting standards. It is the responsibility
of the inspector to evaluate these systems with respect to their compliance
with regulations on a continuing basis. The following will describe the
observational and measurable characteristics by which the inspector can
make judgements as to the probable level of performance of such pollution
control equipment.
Settling/Spray Chambers
As previously mentioned, these are insufficient as control devices
by themselves, especially with natural draft systems. They are capable of
partlculate removal efficiencies in the range of 20 to 50% by weight, at
pressure drops of approximately 1/2 to 1 inch w.c. Their operation quickly
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departs from optimum due to poor water spray distribution, often brought
about by plugging or corrosion of nozzles. This is a direct function of
water recirculation practice which must involve some solids removal and
pH control. The effectiveness of these systems can readily be gauged by
observing the gas flow downstream of the sprays (viewing ports are gen-
erally available). If glowing "blackbirds" (relatively large flakes of
unburned material - generally paper) are seen moving with the gas stream,
then it is obvious that the spray system is not doing its job. In many
cases the spray system is not responsive to furnace temperature excursions,
except possibly by manual operator intervention.
Cycl< nee
Cyclones used in incinerator installations are generally of the large
diameter, tangential entry type. The smaller diameter, "multi cyclone"
installations have a tendency to plug, and are not generally favored.
The larger diameter cyclones are limited to particulate removal efficiencies
ranging from 60 to 75% by weight, when operated at pressure drops in the 3
to 5 inch w.c. range, which must be provided by an induced draft fan.
Cyclones will generally not provide sufficient removal efficiency to meet
existing regulations, although a few rare exceptions can be expected.
The maintenance of an adequate pressure drop across the cyclone is
requited in order for the efficiency to remain at the design level. When
incinerator load is reduced, the exhaust gas volume will subsequently
drop. Unless compensatory air is bled into the system, the cyclone pres-
sure drop will decrease, causing collection efficiency to drop off. Pres-
sure drops should be read from liquid manometer gauges which receive
their signals through clean, dry and relatively straight tubing (free
from sharp bends and kinks). The pressure taps should be true static taps,
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In that the protrusion of the tubing into the flowing gas stream should
be minimized (a flush tap, free from burrs, is ideal). These taps should
be located so that ash accumulations cannot cause plugging. The Inspector
should inspect the taps, tubing and manometers if access is provided.
Pressure drops measured by indirect readouts such as magnahelic gauges
should be viewed with caution. Recent calibration records for these
devices should be obtained, if they are available.
Scrubbers
Scrubbers provide the most flexible form of air pollution control
device in that improved performance can generally be obtained merely by
Increasing the power input to the system, usually without attendant physical
changes. Scrubbers are capable of particulate matter collection efficiencies
in the range of 80 to 99% by weight on municipal incinerators, with pres-
sure drops ranging from 6 to over 25 inches w.c. They are more tolerant
of variations in process conditions and do not require extremely stringent
control of inlet temperature or moisture conditions. However, they do have
attendant waste water treatment problems, which can affect performance,
especially if water recirculation is practiced.
The two parameters of most interest in gauging scrubber performance
are pressure drop and water consumption. There is usually a direct cor-
relation between collection efficiency and pressure drops. The previous
comments on pressure sensing manometers, lines, and taps apply here also,
with an additional concern regarding liquid entrapment in the manometer
tubing. The scrubber design will specify a certain liquid to gas ratio
(g&llbns of serubbihg liqUid per cubic fodt ttf gas scrubbed) which must
be maintained to atieiu-e a sufficient supply M| Uqujfl dvupj.itis tor i-a^furti
of particulates. Scrubber Installations should incorporate either liquid
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flowmeters or liquid pressure gauges whose readings are calibrated against
liquid flows. Recent calibration records should be obtained, if they are
available.
If scrubber water Is recirculated, a measure of water quality should
be available to assure that the effective participate loading to the
scrubber is not being artificially increased by re-release of captured
particulates. Periodic measurement of suspended solids in the recirculated
water and subsequent comparison to design values should be incorporated.
Similar control of the recirculated liquid pH should also be effected.
Electrostatic Precipitators
Electrostatic preclpitators have perhaps been the most successful
particulate emission control device applied to municipal incinerators.
Collection of 90-99% by weight can be readily achieved. Pressure drops
generally range between 3/4 to 1 1/2 inches w.c. and do not correlate
with efficiency as is the case with cyclones and scrubbers. The precip-
itator must be isolated from the process variations inherent in incinerator
operation. The temperature and moisture conditions entering the unit
must be closely controlled to assure that particle resistivities remain
in the optimum range. Wide variations in gas volume flow, resulting in
subsequent variations in throughput velocity, can cause collected particles
to become dislodged and be re-entrained in the gas stream. Flow distribu-
tion must be uniform across the precipitator entrance to prevent channeling
and the associated increased velocities.
Voltage, current, sparking control and rapping cycle parameters are
all established during the precipitator start-up period and should be main-
tained at those levels within allowable tolerances.
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Doghouses (Fabric Filters)
Baghouses have not been widely applied to municipal incinerators,
particularly existing installations since their performance is extremely
sensitive to temperature extremes. The operational temperature range is
very narrow, generally between 250 to 550°F; at higher temperatures, coatings
on the glass filter bags deteriorate and precipitate rapid bag failure. At
the low temperature extreme, the high moisture content of the exhaust gases
combines with the collected particulate to plug and "blind" the bags. Main-
taining operation within this narrow temperature range is considered extremely
difficult in the incinerator environment and this accounts for the paucity
of baghouse installations.
Operated properly, baghouses can achieve 99%+ collection efficiency,
at pressure drops in the range of 6 to 10 inches w.c. The installation
incorporates cleaning of the accumulated particulates from the bags by
mechanical shaking or by reverse air pulsing. Pressure drop will be lowest
Immediately after cleaning, and highest just prior to cleaning. As with
preclpitators, cleaning cycle duration and frequency are established during
initial operation and should be maintained at these values within specified
tolerances.
General Physical Considerations
As inspector can obtain an impression of how well pollution control
equipment has been performing by noting certain physical aspects of the
installation which could be indicative of poor practice or malfunctions.
He should be aware of the following:
o Evidence of leaks itt ducts, flanges and around dampers or other
©pehinBfl whieh fequire eeale, eati indiealt? potentially upset flow
patterns, unwanted gag ppoHng and e*ee§8 04?, additional pressure
loas etc.
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o Evidence of corrosion which can result in leakage and precip-
itate malfunctions in gas and liquid flow components.
o Evidence of plugging of gas and liquid flow passages, dust collector
hoppers, etc. as a consequence of the high moisture content of the
gas stream (for example hoppers which plug repeatedly may show
signs of having been frequently pounded with hammers to loosen the
plugging deposit).
o Evidence of large particle carryover, which can be indicative of
buildup on duct/fan/control surfaces. Periodic loosening of these
deposits and attendant high emissions can occur due to vibration,
high gas velocity, etc.
o Evidence of excessive fan vibration due to an imbalance caused by
material buildup on or corrosion of rotating surfaces.
o Evidence of excessive heating of control components (discoloration,
etc.) which could indicate adverse temperature excursions, causing
permanent damage to key components.
Visual observations of exhaust plume opacity can be indicative of
poor combustion or inadequate pollution control. However, the inspector
must be cautious in his evaluation since high levels of excess air and/or
a steam plume tend to mask the real smoke density levels. Enforcement
actions against municipal incinerators based on opacity violations are
somewhat rare. A case built upon stack test results, application of emis-
sion factors and estimated control equipment efficiency levels, has been
and will probably continue to be the mechanisms by which the compliance
status of such units is determined.
Instrumentation/Records
Most existing incinerators do not provide a plethora of operational
instrumentation or informative records. While some incinerators may ini-
tiate operation with an excellent complement of instruments, they are seldom
maintained operational (generally because qualified instrument technicians
are not available).
Burning rate Is seldom a real-time factor in that it Is based on truck
scale weighing prior to discharge to the pit. There can be a lag time
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Tanging from several hours to several days between refuse input measure-
ment and actual burning. The determination of instantaneous burning rate,
therefore, is usually accomplished by means of the subjective judgement and
experience of the operators. A measure of furnace exit gas temperature is
usually provided on a chart recorder. The operators generally strive to
keep this instrument operational, in that it provides them with the only
real-time gauge of the combustion process. After several months of oper-
ation using these temperature read-outs and manipulating grate speed,
combustion air, and possibly mixing refuse in the pit, a diligent operator
can come qui'.e close to optimizing the operation. The inspector cannot
expect to find available manually recorded readouts of the many operational
variables at every incinerator installation. If possible, he should en-
courage operators to record such information, if it is not a current prac-
tice, in order to facilitate future inspections.
5.2 Inspection Checklists
The foregoing discussion provides the inspector with technical back-
ground on the application of air pollution control equipment to municipal
incinerators; it also summarizes operational experience with such equip-
ment, but does not provide a quantitative method for evaluating the equip-
ment performance on a continuing basis.
In order to accomplish such evaluations, detailed checklists are nec-
essary. These provide a thorough record of the condition of the equipment
at each inspection and, by means of readily measurable parameters, give a
quantitative indication of whether the design collection efficiency is
being maintained.
Three checklists are presented in this section. The first is used
at an initial inspection, that is, at the occasion of the first visit of
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enforcement personnel to the Incinerator site. This checklist is designed
to provide broad, baseline information on the incinerator operation and
its pollution control equipment.
The second checklist is used at the time of an official compliance
stack test, which may have been ordered as a result of the initial in-
spection.
The third checklist is used for subsequent periodic inspections,
which will follow the initial inspection, and if ordered, the compliance
test. This checklist will relate current operating parameters to those
established as baseline information in the first two Inspections.
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5.2.1 Initial Inspection Checklist
Inspector Name & Title
Date
File No
A. General:
1. Name of Facility_
2. Address
3. Name of Plant Contact
4. Source Code No.
5. Age of Facility
6. External Appearance (Comment on Stack Plume, Noise, Odor, Etc.)
Process Description (Attach Schematic Diagram)
1. Charging Method Batch Continuous
2. Furnace Type
3. Grate Type
4. No. of Furnaces Capacities (TPD)
5. Furnace Grate Area(s)
5. Furnace Draft Natural Induced
''. Pollution Control Equipment Spray Chamber Cyclone
Scrubber Electrostatic Precip.
Bag Filter
3. Operating Schedule Hr/Day Days/wk wk/yr
9. Actual Burning Rate (TPD)
10. Auxiliary Burners? Fuel Type?
Refuse Characteristics
1. Refuse Analysis (if available)
2. Composition Estimate (Z's) Residential,
Commercial Industrial
3. Nature & Frequency of Industrial Waste
4. Refuse Variability
5. Refuse Preparation Practices (give details)
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D. Operational Factors
1. Nature & Frequency of Shut-Down/Startup Procedures
2. la Refuse Mixing in Pit Practiced?
3. Is there evidence of Furnace "Puffing"?
4. Does operator modulate burning rate, combustion, air, and refuse mix-
ture to optimize operation? (give details)
5. Has this Incinerator been subject to frequent malfunctions?
E. Emission Information
1. Has the Incinerator been subject to a particulate matter Emission
Test within the last 3 years? (append copy of test report)
2. Test method used EPA Method 5 ASME
ASTM Other
3. What were the emission results?
Ib/hr
Ib/ton refuse
grains/DSCF @ 12% C02
lb/1000 Ib gas @ 50% excess air
4. Applicable emission regulation
5. If no test has been conducted what are the estimated particulate
emissions based on acceptable emission factors?
emission factor (Ib/ton)
assumed burning rate (ton/hr)
estimated uncontrolled emissions (Ib/hr)
assumed control efficiency
estimated controlled emissions
conversion of emissions to units uf emission regulation
(list assumptions)
F. Compliance Status (check one)
1. Facility never previously under any enforcement action
2. Facility presently out of compliance
3. Facility under notice of violation
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4. Facility presently on a compliance schedule
5. Facility presently operating under a variance
6. Facility presently in compliance
7, Facility to be shutdown (give schedule)
8. Facility subject of neighborhood complaints
G. Physical Observations
1. Condition of equipment for refui.e delivery and charging
2. Condition of burning components (grates, refractory, air supply, etc.)
3. Condition of residue handling components (quench, conveyor, etc.)
4. Condition of gas cooling equipment (nozzles, water handling, distribution
etc.)
5. Condition of air pollution control equipment
5(a) Is there evidence of corrosion?
5(b) Is there evidence of plugging?
5(c) Is there evidence of prior temperature excursion?_
5(d) Is there evidence of liquid or air leaks?
6. Comment on general housekeeping practice
7. Comment on neighborhood image of operation
8. Estimated plume opacity Observation conditions (location, time,
humidity, cloud cover . . .)
H. Plant Records
1. Are satisfactory records available as to burning rate? (Give details)
2. Are satisfactory records available as to nature, duration and frequency
of shutdowns, startups, malfunctions outages? (Give details)
3. Are chart records kept for furnace and pollution control equipment
inlet toraperoturos? ,
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A. If opacity monitors are installed, are chart re .ords available?
5. Has the plant available complete and up to date drawings and specifi-
cations for all operating equipment?
I. Plant Instrumentation
1. Are instruments in satisfactory operating conditions (Give details)
2. Obtain readings for the following parameters if instruments are avail-
able or operational (Obtain charts if possible)
(a) Furnace exit gas temperature F (Note location of sensor)
(b) APC device inlet temperature °F (Note location of sensor)
(c) Overfire air draft in. H20 (Note location of sensor)
(d) Underfire air draft in. H20 (Note location of sensor)
(e) Grate speed or equivalent (Indicate units)
(f) Burning rate Tons/hr
(Indicate how obtained)
(g) Flue gas composition
02 % (Note location of sensor)
C02 % (Note location of sensor)
CO % (Note location of sensor)
(h) Emission opacity % (Note location of sensor)
(i) Precipitator spark rate sparks/min
(j) Precipitator secondary voltage ,_kIV (by section)
(k) Precipitator secondary current mA (by section)
(1) Cyclone pressure drop in H20 (Note location of sensor)
(m) Scrubber pressure drop in H20 (Note location of sensor)
(n) Scrubber water rate GPM (Note location of sensor)
(o) Spray chamber water rate GPM (Note location of sensor)
(p) Fabric filter pressure drop in H20 (Note location of)
(sensor)
(q) Precipitator rapping frequency (by section)
(r) Fabric filter cleaning frequency (by section)
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(s) Water treatment system
Suspended solids concentration mg/1
PH
(t) Recirculation percentage to scrubber and spray
(u) Slowdown rate GPM
J. Pre-Test Information
1. Will a particulate emission test be required to ascertain
comp1iance ?
2. Are sampling ports and platform in place?
(a) Number of ports
(b) Size of ports
(c) Stack Inside diameter at port level_
(d) Stack wall thickness at port level
(e) Platform width safe rails?_
safe ladder?
(f) Height of ports above ground ft.
(g) Height of ports above breech entry ft.
(h) Height of ports below stack exit ft.
(1) If no ports or platform, height of stack available above breech
entry f t.
(j) If no ports, give information on variation of stack diameter
with height
3. How will refuse burning rate be determined for emission test?
(a) Pre-weighed refuse used only for test__
(b) Truck scales
(c) Manual weighing
(d) Sampling of craneloads and counting of loads
4. What is recommended elapsed time to be granted to facility to arrange
for and complete emission test?
5. Will the facility be required to institute any record-keeping proce-
dures preparatory to the test or future inspections?
(a) Give detailed requirements (readings to be taken, frequency,
data format, supervision needed, etc.)
(b) If continuously recording instruments presently inoperative are
to be reinstated, give schedule for such reinstatement.
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(c) If new continuous monitors are to be purchased and installed,
give schedule for such installations.
K. Post Inspection Communication
1. Will the facility be notified of the results of the inspection?
2. Are documentation letters required to confirm agreed upon details re-
garding test arrangements and instrumentation?
3. Are official notices required in accordance with regulations?
Test plan?
4. Other parties to be informed
Test consultant
State agency
Local agency
Regional agency
EPA
Manufacturer of air pollution control equipment
L. Evaluation of Prior Emission Test (Inspector should obtain copy of test re-
port and append to this checklist)
1. Were acceptable test procedures followed?
2. Were the tests conducted under the jurisdiction and approval of a reg-
ulatory agency?
3. Were acceptable pre-test and test plan procedures followed?
4. Were the tests done for Information only (as opposed to determining
official compliance status)
5. Is the testing firm well-known for satisfactory work?
6. Were three satisfactory tests completed?
7. What were the resulting emission values
(units)
8. Are there any significant differences from test to test (specify)?
9. Are there any significant process differences between the tine of the
prior test and the present?
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10. Are the tests acceptable or not acceptable as baseline compliance
status, information (provide brief supporting discussion)
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5,2.2 Compliance Test Evaluation Checklist
Inspector Name and Title
Date
File No._
A. General
1. Name of facility
2. Address
3. Name of plant contact
4. Source code no.
5. Age of facility
6. Name of test firm_
7. Address
8. ' Name of test firm contact
B. Test Plan (Append copy to this checklist)
1. Has test plan been filed and approved?
2. Does test plan reflect agreements of pre-test discussion at time of
initial Inspection (or other visit)?
3. If test plan reflects differences have these been justified?
4. Do all concerned parties have copies of test plan?
5. Has a pre-test conference to discuss the plan been held?
6. Are all parties thoroughly familiar with the details of the plan?
C. Incinerator Operating Conditions During Test
1. Will the refuse to be burned during the test be typical of normal
operation?
2. How has this been determined?
3. Will refuse be preweighed?
4. If not, how will burning rate be determined?
5. Is refuse moisture content satisfactory?
6. Have arrangements been made to communicate process variations to the
test team?
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7. Will the Incinerator be capable of sustained operation to allow for
testing beyond the planned schedule in case of test malfunctions?
D. Test Equipment/Test Team
1. Is the testing organization well known to the inspecting agency?
2. Are they qualified?
3. Is their equipment of a satisfactory type and in good working order?
4. Have the data sheets been inspected at the beginning and completion
of all tests?
5. Have sample acquisition and handling techniques been observed and
found to be satisfactory?
6. Have nomograph settings been reviewed and found satisfactory?_
7. Have probe cleaning procedures been satisfactory?
8. Have post test calculations for isokinetic conditions shown satis-
factory operation?
9. Has process coordination been satisfactory?
E. Test Condition Data
1. Record location of sampling points with respect to breech entry and
stack exit, if different from test plan
2. Record length to diameter ratios associated with above
3. Record No. of sampling points (total and per port) required for above
in accordance with EPA method 5
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4. Teat Details
Record values in accordance with the following Table as a check on
the information to be obtained by the test team and as Independent docu-
mentation. This should be done for all tests.
Test No. Start Time
Preliminary Traverse Run (Method 1)
Chosen Nozzle Diameter in.
Train Leak Check
Moisture Determination (Method 4)
Moisture Content %
ml Collected/Gas Volume ml ft3
Combustion Gas Analysis 02 %
C02 %
CO %
Dry Gas Meter Reading Before Test ft3 @
Dry Gas Meter Reading After Test ft3 @
Volume Sampled ft3
Test Duration
Average of Meter Orifice Pressure Drop
Average Duct Temperature
Velocity Head at Sampling Point
Meter AH@*
Repetition Start Time
Repetition Finish Time
Finish Time
Yes No
D D
D D
D D
(time)
(time)
minutes
inches
°F
inches H20
*0ri£lce prosnurn differential pumping 0.75 ft of dry air
•C Htimdard cuiu!ltlonii.
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F. Instrumentation Data
Record values in accordance with the following table, as a check on
the information to be obtained by the test team, and as independent
documentation
ITEM
Secondary Chamber Temp.
AFC Device Entry Temp.
Overfire Air Draft
Under fire Air Draft
Grate Speed
Refuse Measuring Sensors
02
C02
CO
Opacity Monitor
Precipitator
Spark Rate
Secondary Voltage
Section No.
Section No.
Section No.
Section No.
Section No.
Section No.
Secondary Current
Section No.
Section No.
Section No.
Section No.
Section No.
Beefcititi tig.
Bcrubber
Water Rate
Prenaure Drop
UNITS
°F
°F
In. H,0
In. H,0
indicate units
Indicate units
%
%
%
%
sparks/rain
kV
mA
gal./mln
In. tbO
1
/ALUES3
See Table 5-1 for recommended frequency of recorded values.
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Table 5-1
Incinerator Operating Conditions Which Affect Emissions
Observation
Location
Comments
09
*»
I
INCINERATOR
Secondary chamber temperature
Flue gas concentration (CO2* CO, 0,)
Onderfire air draft
Overfire air draft
Grate speed
Crane weight sensors
CONTROL DEVICE
Control device entry temperature
Electrostatic precipitator
Spark rate/section
Voltage/section
Current/section
Scrubber
Hater rate
Pressure drop
Baghouse
Pressure drop
Control panel gage
Control panel gage
Control panel gage
Control panel gage
Control panel gage
Loading area
Control panel gage
Meter on precipitator control
panel
Meter on precipitator control
panel
Meter on precipitator control
panel
Ask operator
Control panel gage or nanometer
on scrubber
Control panel gage
Note thermocouple location in
combustion chamber. Record values
every 20 minutes
Many incinerators do not monitor
overfire and underfire air draft.
Record every 20 minutes
Record every 20 minutes
Record every 20 minutes
Record twice per performance test
Record twice per performance test
Record twice per performance test
Record twice per performance test
Record twice per performance test
Record twice per performance test
Record twice per performance test
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5.'2.3 Periodic Compliance Inspection Checklist
Inspector Name & Title
Date
File No_
A. General:
1. Name of facility
2. Address
3. • Name of plant contact_
4. Source code no.
5. Age of facility
6. External Appearance (comment on stack plume, noise,odor, Etc.)
7. Give reference to previous inspections
(a) Initial inspection date File no
(b) Source test inspection date File no
(c) Periodic inspection date(s) & File no's
8. State compliance status as of last previous inspection
9. List record keeping requirements established by previous inspections
and give evaluation (satisfactory - unsatisfactory)
10. List any pertinent information relative to changes in the impact of
this operation on the surrounding community since the last inspection
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B. Process Description (Attach Schematic Diagram)
1. Charging Method Batch Continuous
2. Furnace Type
3. Grate Type
4. No. of Furnaces Capacities (TPD)_
5. Furnace Grate Area(s)
6. Furnace Draft Natural Induced
7. Pollution Control Equipment Spray Chamber Cyclone
Scrubber Electrostatic Precip.
Bag Filter
8. Operating Schedule Hr/Day Days/wk wk/yr
9. Actual Burning Rate (TPD)
10. Auxiliary Burners? Fuel Type?
C. Refuse Characteristics
1. Refuse Analysis (if available)
2. Composition Estimate (%'s) Residential,
Commercial Industrial
3. Nature & Frequency of Industrial Waste
A. Refuse Variability
5. Refuse Preparation Practices (give details)
D. Operational Factors
1. Nature & Frequency of Shut-Down/Startup Procedures
2. Is Refuse Mixing in Pit Practiced?
3. Is there evidence of Furnace "Puffing"?
A. Does operator modulate burning rate, combustion, air, and refuse mix-
ture to optimize operation? (give details)
5. Has this Incinerator been subject to frequent malfunctions?
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E. Physical Observations
1. Condition of equipment for r.efuse delivery and charging
2, Condition of burning components (grates, refractory, air supply, etc.)
3. Condition of residue handling components (quench, conveyor, etc.)
4. Condition of gas cooling equipment (nozzles, water handling, distribution
etc.) .
5. Condition of air pollution control equipment
5(a) Is there evidence of corrosion?
5(b) Is there evidence of plugging?_
5(c) Is there evidence of.prior temperature excursion?_
5(d) Is there evidence of liquid or air leaks?
6. Comment on general housekeeping practice ^____^^^_^
7. Comment on neighborhood image of operation_
8. Estimated plume opacity Observation conditions
(location, time, humidity, cloud cover . . .)
F. Plant Records
1. Are satisfactory records available as to burning rate? (Give details)
2. Are satisfactory records available as to nature, duration and frequency
i
of shutdowns, startups, malfunctions outages? (Give details)
3. Are chart records kept for furnace and pollution control equipment
inlet temperatures?
4. If opacity monitors arc installed, are chart records available?
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5. List and give details as to addizional record-keeping practice
instituted since last previous Inspection
G. Control Equipment
1. Electrostatic Precipitator
Section
Primary Current, amps
Primary Voltage, volts
Secondary Current, mA
Second Voltage, kV
Spark Rate, spk/min
2. Scrubber
Module
Liquid Flow, gal
Pressure Across
. /min.
Scrubber, in. H_0
3. Fabric Filter
Compartment
Pressure Drop Across Fabric
Filter, in.H20
Additional Observations:
A. CONTROL PANEL
Secondary' Chamber Temp.
APC Device Entry Temp.
Time
°F
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Underfire Air Draft . in-
Overfire Air Draft in. 1120
02 Analyzer %
COj Analyzer %
CO Analyzer %
Grate Speed (indicate units)
Refuse Measuring Sensors (indicate units)
5. RECORDS
Temperature Charts (Dated and filed by Incinerator Personnel)
Satisfactory Unsatisfactory
Secondary Chamber I I I_J
APC Device Entry Gas CU L)
Hours of Operation
Charging Rate, T/hr
Daily Collection, T/day
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6.0 COMPLIANCE SCHEDULE DEVELOPMENT - BACKGROUND
6.1 General
The installation of pollution control equipment on an existing In-
cinerator is but one option available to a municipality to meet the
applicable emission limitations. The decision to install equipment is
generally made after all the possible alternatives for solid waste dis-
posal have been evaluated as to costs, availabilities, applicability,
etc. Many municipalities choose to shut down their incinerator and opt
for sanitary landfill operations because the costs of land and trans-
portation are often less than those associated with upgrading and operating
their present Installation. However, in large, densely populated areas
such as exist along the east coast of the U.S. (see Figure 2-1, Incinerator
Belt), where land prices are extremely high, the costs associated with
sanitary landfill operations are often greater than for incineration. In
these cases, therefore, incinerator upgrading is likely to be the most
economically attractive alternative to comply with air pollution regulations.
The purpose of this section of the Manual is to assist enforcement
personnel in their development of an effective and reasonable compliance
schedule for implementation by the incinerator owner. It is intended to
apply to those situations where upgrading is the selected option for
compliance. It does not address the use of any other solid waste manage-
ment alternatives but the contents may assist the municipality in
evaluating the upgrade option against other choices.
The Compliance Schedule is the means by which a regulatory agency
specifies a timetable outlining the sequence of events required of a
municipal incinerator owner to meet source emission limitations. It con-
sists of many Interrelated elements and is one of the major components
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of the overall decision and activity process followed by the municipality.
Figure 6-1 outlines the elements of such an overall decision process.
Figure 6-1
Elements of Municipality Decision Process
to Effect Incinerator Compliance
The spectrum of possible approaches toe upgrading an existing municipal
Incinerator could include any or all of the following components:
(1) Improve refuse handling and charging to provide for more stable
combustion
(2) Eliminate air flow leaks to reduce excess air and improve com-
bustion
(3) Provide evaporative or convective cooling to reduce exhaust
temperatures and permit installation of emission control
equipment
(4) Install new or replace existing air pollution control systems
(upgrading)
While the first two items would undoubtedly improve the operation
of a municipal incinerator, they would not usually, in themselves, effect
compliance. This Manual section will deal with upgrading to achieve
major reductions in pollutant emissions and will consider the basic equip-
ment as well as the ancillary items required for effective operation. The
following items will be considered:
(1) Costs of gas cooling and air pollution control equipment
(2) Capabilities of vendors to supply and install control systems
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(3) The time required to acquire and install control systems
(A) The methods used by municipalities to fund incinerator upgrading
projects
6.2 Air Pollution Control Equipment Costs
6.2.1 Basis of Analysis
In order for municipalities to objectively evaluate the alternatives
open to them for upgrading existing municipal incinerators, those alter-
natives must be described in terms of their costs, both for the initial
purchase and for their annual owning and operating charges. As discussed
previously, present particulate matter emission regulations for existing
incinerators are sufficiently stringent to preclude the use of rudimen-
tary particulate matter collection equipment such as settling chambers
and cyclones. Only the more sophisticated high energy scrubbers and
electrostatic precipitators can be employed to achieve current or expected
standards which would require at least a 90% collection efficiency, however
most State regulations require even higher efficiencies. Thus, the cost
analyses which follow are restricted to consideration of high energy
scrubbers and electrostatic precipitators only. Although baghouses
are generally included in discussions of high efficiency particulate
matter collection equipment, they have not been successfully applied on
municipal incinerators, and are not expected to be a factor in future up-
grading projects. Thus, they have not been included in the analyses of
costs to be presented.
Size Considerations
Since the cost of particulate control equipment is a function of the
gas volume flow to be treated, cost relationships have been developed on
that basis. For existing municipal incinerators, the quantity of flue
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gases generated Is not only related to the refuse burning capacity of the
unit but also to several other factors, the most significant of which is
excess air. Existing units, however, exhibit a wide range of excess air
levels. This variability is the result of the deliberate as well as the
casual, uncontrolled introduction of airflow into the furnace. As the
amount of excess air increases, the total exhaust gas volume to be treated
increases. This in turn dictates the use of larger fans, and bigger
ducts with increased energy requirements, causing total emission control
system costs to escalate.
Otl.er factors that influence the volu.ne flow to be handled by con-
trol equipment include refuse composition, furnace discharge temperature,
and the quantity of quench water which must; be evaporated Lo reduce ex-
haust temperature.
In order to reduce these requirements to a common basis for com-
parison, Figure 6-2 has been prepared. The values presented are based
on the combustion of municipal refuse whose average heating value was
assumed to be 4400 BTU/ pound. A range of excess air levels is presented
for both refractory lined furnaces and units utilizing heat removal through
water walls or waste heat boilers. The gases leaving the furnace have
been cooled to 500°F for compatibility of analysis. For the case of re-
fractory walled furnaces, this cooling is accomplished by introduction
of evaporative cooling wa.ter in the amount of 2.0 to 2.6 pounds per pound
of refuse, depending on the furnace exit temperature, which can vary from
1760°F to 1300°F for the range of conditions shown (100% to 200% excess
air). The requirement for this evaporative cooling accounts for the
higher total exhaust gas flows for refractory units.
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Pig. 6-2.
Municipal incinerator exhaust gas flow
rates (ACFM) vs. furnace capacity (TPD) for
refuse with HHV of 4400 Btu/lb and at
500° F temperature entering air pollution
control equipment.
500° F reached by water spray for
refractory wall furnace; 2.0- 2.6 Ib H.O/lb
refuse.
600° F reached by corrective cooling for
water wall furnace; 0 Ib H20/lb refuse.
o-s
I
300
I
100
i
I
c.I
50
10
Excess.
air
200%
'150%
Refractory ,
wall furnace <•
Water wall
furnace
I I I ( 1/1 I I 11
Basis: 24 hour
operation
I J I I
50 100 500
Furnace capacity • TPD (tons per day)
It should be understood that the values presented in Figure 6-2 will
differ significantly for other refuse compositions or heating values and
for values of control equipment inlet temperature other than 500°F. For
that reason, Figures 6-3 and 6-4 have been developed. Figure 6-3 shows
the effect of changes In refuse heating value on the total exhaust gas
flow generated. Figure 6-4 similarly shows the effects of different
coolinp, rates on the total gas flow. Thus, by applying the information
presented in these three figures, furnace design/operating conditions and
characteristics may be translated into the required size of the particulate
emission control equipment. Once this information has been generated,
an estimate of total system capital and operating costs may be determined.
Efficiency Considerations
In order to meet the majority of present and anticipated emission
limitations for particulate matter, collection efficiencies of at least
90% must be achieved. Some states and NSPS, however, require efficiencies
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+30
+20
g +10
-10
Refractory wall furnace
Water wall furnace
4000 4400 4800 5200 5600
Municipal refuse higher heating value Btu/lb
Figure 6-3
Variation of Municipal Incinerator
Exhaust Gas Flow Rates (%) vs. Refuse
Heating Value at 500° F
(Temperature entering air pollution
control equipment. 4400 Btu/lb is
nominal heating value. Relationship
is independent of excess air value.
Ref. Figure 6-1)
+25
+20
+15
£ 0
&
•16
-20
-25
/ Refractory wall furnace
" /
/
250 500 750
Temperature entering air pollution control
equipment - ° F
Figure 6-4
Variation of Municipal Incinerator
Exhaust Gas Flow Rates (%) vs.
Temperature entering Air Pollution
Control Equipment
(Relationship is independent of excess
air value and refuse heating value.
Ref. Figure 6-1. Temperatures are
reached for refractory wall furnace by
water spray and for water wall furnace
by convective cooling)
in the mid to upper nineties in order to meet the appropriate emission
limitations. Cost relationships have therefore been developed for effi-
ciencies ranging from 90% to 99%. In general, increased efficiency require-
ments demand increased expenditures for electrostatic precipitators; improved
efficiencies generally relate to initial purchase cost because more effective
particle capture requires additional collector plate area and overall unit
volume to provide sufficient residence time for the particles to be captured.
Scrubbers on the other hand, achieve improved efficiencies by increasing the
power expended in bringing the liquid and the particles to be captured Into
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intimate contact, and this can often be achieved with little or no physical
change to the system. Thus, increases in scrubber efficiency generally
require increases in operating costs.
The cost curves which follow relate the total installed and annual owning
and operating costs of electrostatic preclpitators and scrubbers to the exhaust
gas volume flow rate which must be treated. Annualized cost relationships
have been presented on the basis of annual operating hours since this appears
to be the most significant variable. The cost curves are presented for three
values of precipitator efficiency H 90%, 95%, and 99%, and four values of
scrubber pressure drop - 10, 15, 20 and 25 inches w.c., corresponding to 90,
9A, 96 and 97 1/2% efficiency.
Gaa Cooling Considerations
A temperature of 500°F was chosen to be representative of the general
range of inlet conditions required for electrostatic precipitators (approxi-
mately 400 to 6008F). Since scrubbers generally continue the cooling pro-
cess to saturation conditions, the inlet temperature can be substantially
higher than 500°F. In some cases, scrubbers whose inlets are refractory
lined can accept gases directly from the furnace and accomplish the gas
cooling in a single unit. In other cases, some fraction of the gas cooling
process must be accomplished prior to scrubbing.
Gas cooling for precipitators or scrubbers involves the use of either
a gas quenching chamber or a waste heat boiler. When applied to precipitators,
the quenching chamber must be carefully designed and operated to prevent
the carryover of liquid water droplets which can cause operational mal-
functions and damage. For scrubbers, however, this requirement is not
critical. Waste heat boilers accomplish the cooling of the gases with-
out addition of either quench water or dilution air to produce steam or
hot water from which energy may be extracted. If energy la not extracted,
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the heat must be dissipated either by "bloving" steam to the atmosphere or
through the use of a condenser and a cooling tower.
In general, it is unlikely that waste heat boilers would be Installed
to achieve gas cooling on existing incinerators unless the steam produced
is highly marketable and offers significant advantages over conventional
means of steam production. However, this means of cooling does offer an
alternative to the gas quenching chamber, and may be feasible in selected
Installations.
Total installed cost relationships have been developed for gas quenching
chambers and waste heat boilers as a function of capacity expressed in terms
of exhaust volume flow.
6.2.2 Capital Costs
Gaa Conditioning Equipment
Capital costs including installation for quenching chamber and waste
heat boiler gas conditioning systems are presented on Figure 6-5. Values
have been normalized on the basis of dollars per actual cubic foot per
minute of gas and are presented as a function of the system capacity in
actual cubic feet per minute. These capital cost estimates incorporate
all the following auxiliary components for both systems:
o Pumps
o 'Piping
o Temperature Controls
o Ductwork
The quenching chamber system utilizing fine sprays as the delivery
mechanism exhibits about a 3:1 spread in capital costs over the range of
system capacities presented. This wide range reflects an economy of scale
since the cooling chamber shell costs do not increase in direct proportion
to system capacity. The waste heat boiler on the other hand exhibits) a
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2:1 cost spread over the same size range but Is about an order of magnitude
more expensive than the cooling chamber. The use of a waste heat boiler
does, however, provide the opportunity for generating steam which could be
sold to offset operating costs if an adequate market for the steam is available.
100
&
20
10
Waste heat boiler
250 psig steam
Gas quenching
chamber
Basis: gases cooled to 500° F.
i i i
10 20 40 100 200 300
Capacity (103 ACFM)
Figure 6-5
Air Pollution Control Systems total Installed Costs
for Gas Quenching Chamber and Waste Heat Boiler
Emission Control Equipment
Capital costs including installation for electrostatic precipitator
control systems are presented in Figure 6-6. Values have been normalized
on the basis of dollars per actual cubic foot per minute of gas treated
and are presented as a function of system capacity in cubic feet per
minute. Total installation system costs are based on installation costs of
$2 for each dollar of basic equipment cost. Cost relationships have been
developed for three efficiency levels - 90%, 95% and 99%. The high effi-
ciency system results in significant additional costs over the lower effi-
ciency systems due to the relationship between efficiency and collection
plate area, associated electrical components and overall collector volume.
These capital cost estimate! incorporate all auxiliary components such as:
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o Fans/motors
o Ductwork and valves
o Electrical components
o Associated system controls
o Particulate collection and disposal features
100
u.
20
10
1 6
I 4
I,
99% efficiency
95% efficiency
90% efficiency
Basis: gates cooled to 500° F.
10 20 40 100 200 400
Capecity (103 ACFM)
Figure 6-6
Air Pollution Control Systems Total Installed Costs
Electrostatic Brecipitators
Capital costs, including installation, for yenturi scrubber control
systems are presented in Figure 6-7. The values are expressed as a function
of four pressure drop levels - 10, 15, 20 and 25 inches of water column.
These pressure drops, when applied to "typical" municipal Incinerator fly
ash, result in collection efficiencies of about 90%, 94%, 96% and 97 1/2% by
weight (See Figure 4-2). The cost estimates incorporate auxiliary components
such as:
o Pumps
o Nozzles
o Piping
o Water treatment and recirculation components
o Fans/motors
o Ductwork and valves
o Structural components
-99-
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Total Installed system costs are based on installation costs ranging
from $1.50 to $4 for each dollar of basic equipment cost depending upon
scrubber efficiency.
Only slight differences in installed cost are noted attributable
largely to fan and motor costs, since little change in physical size of
the units is necessary to accommodate the increases in pressure drop. There
are, however, significant differences in operating costs.
100
C 20
^
" 10
I 6
_ 25" AP
u. 20" AP
- 15" AP
_ 10" A P
Basis: gases cooled to 500° F.
97*2% efficiency
96% efficiency
94% efficiency
90% efficiency
10 20 40 100 200 300
Capacity (103 ACFM)
Figure 6-7
Air Pollution Control Systems Total Installed Costs
Venturi Scrubbers
6.2.3 Annualized Operating Costs
Ga.8 Conditioning Equipment
Annual operating costs for gas quenching chamber and waste heat
boiler gas conditioning systems are described on Figures 6-8 and 6-9.
The dollar values are presented as a function of unit capacity in actual
cubic feet per minute as determined at the outlet of the conditioning system.
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The annualized costs have been developed on the basis of reducing the
exhaust gas temperature from 1800?F to 500°F and Include the following
basic factors:
o Electrical and water costs (primarily for pumping)
o Maintenance costs
o Amortization and Interest
For a given capital Investment, the last cost element Is fixed, whereas
the first two are dependent upon hours of operation. Figures 6-8 and 6-9
show the cost relationships for both types of conditioning systems for one,
two and three shifts of operation, corresponding to 2000, 4000 and 6000
annual operating hours. Note that the annualized costs associated with
a waste heat boiler is four to eight times gre iter than the corresponding
costs for a quench chamber. This is the result of the higher capital cost
payback entailed in a waste heat boiler system. The curves on Figure 6-9
do not reflect the potential savings which could be realized if the steam
produced were marketed.
100 pr
40
e
3
20
10
I 4
I*
3 shifts per day
2 shifts per day
1 shift per day
Basis: eases cooled to 500° F.
I I I 111 I I I I I I
I
i
s
f 3 shifts per day
'- 2 shifts per day
1 shift per day
Basis: gases cooled to 500° F.
I i I I i i 111 i
10 20 40 100 200 400
Capacity (103 ACFM)
Figure 6-8
Air Pollution Control Syutcms
Annual Operating Coats
Gas-Quenching Chamber
10 20 40 100 200 400
Capacity (103 ACFM)
Figure 6-9
Air Polluatlon Control Systems
Annual Operating Costs
Waste Heat Boiler
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'Emission Control Equipment
Annual operating costs for electrostatic precipitator control systems
are shown in Figure 6-10. The dollar values are presented as a function
of unit capacity in actual cubic feet per minute, and for three levels of
precipitator efficiency ranging from 90% to 99% by weight collection effi-
ciency. The effect of annual operating hours on the cost relationship is
also illustrated. The basic cost elements include electrical, water,
maintenance and amortization costs. Note that for a given unit size, dollar
values appear to be relatively insensitive to the number of system operating
hours. This is due to the predominating effect of the fixed annual costs
associated with capital payback for this type of system. The higher annual
cost of the 99% unit over that of the 90% precipitator is also due largely
to the difference in these fixed charges.
100
ita
i
I 20
i
! 10
Range of values for 1 to 3 shifts per day
(2000 to 6000 hours per year)
99% efficiency
95% efficiency
90% efficiency
Basic gases cooled to 500° F.
J I
I 11
10 20 40 60 100 200 500
Capacity (103 ACFM)
Figure 6-10
Air Pollution Control Systems Annual Operating Costs
Electrostatic Frecipitator
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Figure 6-11 presents operating cost information for venturi scrubber
control systems. Four categories of scrubbers are shown, providing collec-
tion efficiencies of approximately 90, 94, 96 and 97%%, by means of 10, 15,
20 and 25 inches water column pressure drops across the venturi throat.
Again the effects of one, two and three shift operating schedules are illus-
trated. It is apparent that the scrubber systems are more sensitive to hours
of operation than preclpitators due to the large power costs.
100
20
10
I Fill I
1 shift per day
(2000 hrs per yr)
Basil: gases cooled to 500° F.
I I I I I I I II I
I I I I I
100
-
120
5 10
\
I
2 shifts per day
(4000 hrs per yr)
Basis: gases cooled to 500° F.
I.I 1 I I I III I
I 1111
I I I I
3 shifts per day
(6000 hrs per yr)
Basis: gases cooled to 500° F.
I 11 I I I I II
J I I I I
10
10
20
40 60 100 200 300 600
Capaolty (103 ACFM)
20 40 60 100 200 300 600
Capaolty (103 ACFM)
Figure 6-11
Air Polluatlun Control Systems Annual Operating Cocts
Venturi Scrubber
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The annual costs associated with owning and operating pollution
control equipment can be significant. Tables 6-1 and 6-2 have been
prepared to outline the extent of such costs for both a scrubber and a
precipitator system, respectively, installed on a 100 and a 500 TPD
Incinerator. Total (operating and amortization) annual costs and costs
normalized to $/ton of refuse charged are presented for a variety of
collection efficiencies and operational schedules.
Plant
Capacity
90
95
99
90
95
99
90
95
99
90
95
99
90
93
99
90
95
99
Ann
Total
$/yr
50,000
63.000
81,000
58.000
71 ,000
90.000
66,000
80,000
100. COO
160,000
L88.000
22S.OOO
192,000
221,000
261,000
225.000
260.000
300.000
ual Coata
Normal! ted Total
(S/ton or refuse)
2.00
2.52
.24
.32
.84
.60
.64
.20
.00
.28
.50
.80
.54
.77
.09
.80
2.08
2.40
Table 6-1
Summary of Annualized Costs
Venturi Scrubber
Table 6-2
Summary of Annualized Costs
Electrostatic Precipitator
Assumptions
(1) 150% excess air
(2) Gas volume
43,000 ACFM for 100 TPD facility
215,000 ACPM for 500 TPD facility
(3) Control device inlet temperature of 500°F
(4) Amoritzation: 6.67%/year (15 year life)
It must be understood, however, that these are only typical examples.
Many situations could alter costs significantly. All assumptions and details
of the calculations to develop annualized costs can be found in the "Docu-
mentation Report for Municipal Incinerator Enforcement Manual".
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6.3 Vendor Capabilities
6.3.1 Regulatory & Enforcement Trends
Existing regulations which govern the emission of particulate matter
from incinerators constructed before the effective date of New Source Per-
formance Standards (NSPS) are being more rigorously enforced. The in-
ability of some of these incinerators to comply with regulations is being
documented by stack emission tests, and where appropriate, the cognizant
regulatory agencies are developing compliance schedules for these sources.
In many cases, the age of the facility and the costs associated with up-
grading to meet emission standards have combined to achieve compliance
by shutdown and the subsequent use of landfilling as the ultimate disposal
method. However, others will choose to upgrade their facility in order
to meet the applicable regulations. The potential for a large number of
upgrading projects raises the question of whether the suppliers of air
pollution control equipment can produce and install the necessary units
over the short period of time likely to be involved, in view of their
already heavy commitments to other industrial segments.
6.3.2 Demands on Equipment Suppliers
The statistics developed on the compliance status and projected
compliance activity for existing municipal incinerators (see Section 2.0)
indicate that there are likely to be 23 upgrading projects, scheduled for
completion over approximately the next three years. Of these projects,
it is estimated that 18 will utilize electrostatic precipitator control
systems and 5 will utilize scrubber systems. The unit sizes could range
from approximately 65,000 to 430,000 ACFM, with an aggregate installed
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cost of about $18 million. There are approximately a dozen qualified sup-
pliers of electrostatic preclpitators and several dozen qualified suppliers
of scrubbing systems in the United States. Surveys of about half of the
preclpitator suppliers and several of the scrubber vendors were conducted.
These contacts have provided assurances that the projected rate of orders
they are likely to receive from incinerator upgrading activity will rep-
resent less than 10% of their total capacity to supply such systems over
the time period Involved. All agreed that this would not represent undue
pressure on their design and fabrication facilities.
6.1-. 3 Conclusion
Upgrading of existing incinerators will occur in selected cases, de-
pending upon location, age, size and other characteristics of a facility
and its surrounding area. The number of such upgradings is not projected
to be excessive and the associated demand on air pollution control equip-
ment manufacturing capability will not cause difficulty for suppliers.
6.A Time Tables/Schedules
6.4.1 Elements of Compliance Schedule
In order for a regulatory agency to develop a compliance schedule
which can be readily kept under surveillance and which can be subjected
to corrective action if needed, a sufficient number of schedule elements
must be identified. A compliance schedule for upgrading an existing
municipal incinerator should contain, at a minimum, the following elements:
o Preliminary investigation *
o Source tests *
o Evaluate control alternatives *
o Commit funds for total program *
-------
o Prepare preliminary control plan and compliance schedule for
agency
o Agency review and approval
o Finalize plans and specifications
o Procure control device bids
o Evaluate control device bids
o Award control device contract
o Vendor preparation of assembly drawings
o Review and approve assembly drawings
o Vendor preparation of fabrication drawings
o Fabricate control device
o Prepare engineering drawings
o Procure construction bids
o Evaluate construction bids
o Award construction contract
o Initiate on-site construction
o Install control device
o Complete construction (system tie-in)
o Startup, shakedown, preliminary source test
o Conduct final compliance test.
Items marked with an asterisk (*) may have occurred prior to the develop-
ment and initiation of a compliance schedule.
Typically, the activities involved in finalizing fabrication drawings
and the equipment fabrication will require the longest elapsed time period.
In some cases preparation of drawings for and completion of site construction
can require even longer periods.
Delays in achieving compliance schedule milestones can be attributable
to any of the following:
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o Finalizing designs/drawings
o Inability of suppliers to obtain raw materials
o Inability of suppliers to obtain auxiliary hardware
o Inability of the municipality to complete site preparation
Often these delays are unavoidable and beyond the control of the operator
or supplier, but equally as often, delays can be attributed to inadequate
project management and an unwillingness on the part of the municipality
to press suppliers to meet commitments and deadlines. The enforcement
agency can serve as a strong catalyst in detecting and correcting these
situations.
6.4.2 Typical Compliance Schedules
Figures 6-12 and 6-13 present typical compliance schedules for the
installation, respectively, of a scrubber and an electrostatic precipitator
on a municipal incinerator. These schedules show elapsed time estimates
for the activities occurring after the regulatory agency has approved the
compliance program. Note that most activities involving the precipitator
installation require up to twice the elapsed time needed for the scrubber.
This is to be expected since the precipitator installation is more complex.
For example, the period required to award the control device contact is 19
weeks for the precipitator and 10 weeks for the scrubber. Fabrication
time is 40 weeks for the precipitator as opposed to only 20 weeks for the
scrubber system. This results In the total elapsed time to completed in-
stallation of the equipment of 95 weeks and 50 weeks. Note that the site
construction activity for the scrubber represents the critical path while
equipment fabrication for the precipitator is the pacing item.
These are typical values, not representing any specific installation
and should be treated as examples only. Each installation will exhibit
its own peculiarities which will influence the overall schedules.
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• Milestones
o
o
!CLESTOXES
I
2
3
4
ACTIVITIES
Designation
A C
A B
C O
O E
f-r
f G
C-l
I-M
M-J
j-a
2t - Activity and duration in weeks
ELAPSED TIME (WEEKS)
Date of submlttal of final control plan to appropriate agency.
Date of award of control device contract.
Date of initiation of on-site construction or installation of emission control equipment
*)ate by which on-site construction or installation of emission control equipment is
completed.
Date by which final compliance is achieved.
Preliminary investigation
Source tests
Evaluate control alternatives
Commit funds for total program
Prepare preliminary control plan and compliance
schedule for agency
Agency review and approval
Finalize plans and specifications
Procure control device bids
Evaluate control device bids
Award control device contract
Vendor prepares assembly drawings
Designation
K-l Review and approval of assembly drawings
l-M Vendor prepares fabrication drawings
M-N Fabricate control device
l-O Prepare engineering drawings
O-P Procure construction bids
P-O Evaluate construction bids
Q— 3 Award construction contract
j-N On-site construction
N-R Install control device
R-4 Complete construction (system tie-in)
4-S Startup, shakedown, preliminary source
test
Figure 6-12
Schedule for Installation of a Wet Scrubber for Particulate
Pollutant Control on a Municipal Incinerator
-------
MILESTONES
I
2
3
4
ACTIVITIES
Designation
A-C
A-B
C-0
o-e
E-F
G-1
1-M
M-J
j-a
2-K
- Milestones
- Activity and duration in weeks
Date of submittal of final control plan to appropriate agency.
Date of award of control device contract.
Date of Initiation of on-site construction or Installation of emission control equipment.
Date by which on-site construction or installation of emission control equipment is
completed.
Date by which final compliance is Achieved.
ELAPSED TIME (WEEKS)
10;
Preliminary investigation
Source tests
Evaluate control alternatives
Commit funds for total program
Prepare preliminary control plan and compliance
schedule for agency
Agency review and approval
Finalize plans and specifications
Procure control device bids
Evaluate control device bids
Award control device contract
Vendor prepares assembly drawings
Designation
K-L Review and approval of assembly drawings
l-M Vendor prepares fabrication drawings
M-N Fabricate control device
l-O Prepare engineering drawings
O-p Procure construction bids
p-O Evaluate construction bids
O-3 Award construction contract
•»_M On-slte construction
N-R Install control device
R—4 Complete construction (system tie-in)
4-5 Startup, shakedown, preliminary source
test
Figure 6-13
Schedule for Installation of an Electrostatic Precipitator for
Particulate Pollutant Control on a Municipal Incinerator
-------
Additionally, these schedules assume single shift work efforts for fabri-
cation and installation. For certain cases, however, enforcement officials
may require multi-shift efforts to complete the project in the most expedi-
tious manner.
6.A.3 Input From Equipment Suppliers
Contacts with suppliers of scrubbers and precipitators tend to con-
firm the typical elapsed times given in Figures 6-12 and 6-13 for completion
of drawings and fabrication. The suppliers also emphasize the individuality
of each installation, and that unpredictable delays can and do occur. In
general the suppliers feel that the procurement periods have lengthened
somewhat over the last few years and may continue to do so. In particular,
suppliers can have difficulties dealing with municipalities, especially
with regard to timely receipt of progress payments, excessively delayed
final payments, etc. These problems can result in the devleopment of an
overly cautious attitude on the part of the supplier and the subsequent
slowing down of progress. If the enforcement agency remains alert to the
potential for these difficulties, it may be possible to avert them by
Judicious mediation.
6.4.4 Conclusion
It is difficult to offer any conclusions regarding the likely trends
in length of compliance schedules for upgrading municipal incinerators be-
cause of the special features inherent in each Installation. Some delays
can be associated with historical difficulties of suppliers dealing
with municipalities; delays in engineering and fabrication are mostly
the result of poor management, and in some cases, bad luck. Mo single
-111-
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remedy can be suggested, except that the enforcement agency <-.an play a
significant role in "keeping things moving."
There is one aspect of scheduling an upgrading program which can be
a critically delaying factor, and which is usually out of the hands of
the enforcement agency. This is the question of municipal funding practice
which will be discussed in Section 6.5.
6.5 Municipal Funding Practices
The requirement for funding a multi-million dollar pollution control
equipment installation has strong community tax rate repercussions. This
frequently involves many lengthy hearings, referendums and town meetings
during which time the upgrading program can only proceed through the pre-
liminary engineering phase. The purpose of this section is to review the
various means by which a municipality can fund pollution control equip-
ment. The alternative financing methods introduced should be used only
as general guidance. The specific method of funding is dependent on the
characteristics of the procurement and the type of contract negotiated.
Local governments may draw capital for equipment from two sources:
current revenues and borrowings. Current •-avenue, or capital budget
financing requires full payment upon delivery. This mechanism is simple
and involves few institutional or legal arrangements, however it is de-
pendent upon the community's ability to raise surplus capital. Borrowings
are the issuance of municipal bonds and notes, or bank loans. Borrowings
are divided into short term options (1-5 years - less than $500,000 capital
required), medium term options (5 to 10 years - $500,000 to $1,000,000),
and long term options (10 to 30 years - over $500,000). If a municipality
cannot raise surplus capital, short and medium term financing places a
heavy drain on government cash flow.
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6.5.1 Short-Term Options
Financial options available to municipalities on amounts less than
$500,000 are the use of capital budget allocations, funds from previously
authorized general obligation (GO) bonds, notes, and bank borrowing. Capital
budget allocation and the use of funds left over from GO bonds are relatively
simple procedures. A municipal note of small face value may be difficult
to sell. Commercial banks often collect groups of these notes for a fee
and then resell them to individual investors. Such fees should be com-
puted into the capital cost of a project. Although direct bank borrowing
is rare, it does take place. Interest rates or such funds are high, how-
ever, it is a means of raising small amounts of capital quickly. Bank
loans are usually used to finance front-end planning and some of the con-
struction costs of expensive facilities.
6.5.2 Long-Term Options
There arc two main long-term options available to municipal govern-
ments: revenue bonds and general obligation (GO) bonds.
Municipal Revenue bonds are long-term, tax exempt obligations issued
directly to municipalities, authorities, or semi-public agencies for amounts
usually over $1 million. Typically, a revenue bond is negotiated rather
than competitively underwritten. Negotiation means the city meets with
one underwriter to determine what profit the underwriter will make. Interest
rates for negotiated bonds are usually higher than competitive rates; however,
the investment banker incurs the cost of providing free advice and the
preparation of the revenue bond circular and official statement. The city
may also find it necessary to hire a consultant to confirm the investment
banker's estimates of costs and revenues.
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Municipal Revenue bonds do not require voter approval. This may re-
duce delays and costs that result from citizen vote. Revenue bonds are
not restricted by municipal debt ceilings, because they are not a function
of the tax base. These bonds require detailed disclosure of the technical
basis, economical viability, administration, and financing of the project.
The reports and summaries required are expensive to prepare and the bonds
do have high fixed administrative and transaction costs. As noted pre-
viously, revenue bonds have higher interest rates than GO bonds-usually
30 to 45 basis points (a point equals 1/100 of a percent). Interest rates
are higher due to higher risk involved by investors. This risk can be
lowered, however, through contractual obligations, so that revenue bonds
take on the risk characteristics and interest rate of GO bonds. Revenue
bonds may only be used for a single project. This type of bond is usually
used when a major project will generate enough revenue to operate and main-
tain the facility, as well as pay the interest and principal on the debt.
General Obligation bonds - are long term, tax-exempt obligations
secured by the full-faith-and-credit of a political jurisdiction which
has the ability to levy taxes. The capital market determines the credit-
worthiness of a local government and does not specifically evaluate the risks
of a particular project. Typical GO bonds are offered competitively for
sale to bidders. The bidder offering the lowest net interest cost to the
city wins the right to place the bonds with its customers.
Voter approval is required to offer a GO bond. GO bonds usually have
lower interest rates than revenue issues. The lower interest rates is a
result of the fact that the city guarantees the bond by its tax-collecting
capacity. The minimum offering size for GO bonds is approximately $500,000.
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If a project costs less than $500,000, several projects may be grouped to-
gether under a single offering, as long as voter approval is reached on
each project.
It should be noted that a municipality may require the services of
financial consultants, investment bankers, and bond counsels. All of these
i
professionals offer services which allow a municipality to best understand
the comparative costs of various funding practices. The cost of these
services should be included in the overall capital costs of a project.
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REFERENCES
It Technical-Economic Study of Solid Waste Needs and Practices,
Report (Sw-7c) under Contract No. PH 86-66-163, Combustion
Engineering, Inc., Windsor, CT. Public Health Service Publica-
tion No. 1886, 1969.
2. Air Pollution Control Compliance Analysis Report on Municipal
Incinerators, under Contract No. 68-02-OP99 for Environmental
Protection Agency by Vulcan-Cincinnati, Inc. August 7, 1974.
Revised August 27, 1974.
3. Achinger, William C. and Richard L. Baker. Environmental Assess-
ment of Municipal-Scale Incinerators. Report (SW-111) for Environ-
mental Protection Agency, Office of Solid Waste Programs, 1973.
4. DeMarco, Jack, et al. Municipal-Scale Incinerator Design and
Operation. U.S. Department of Health, Education, and Welfare,
Bureau of Solid Waste Management. Public Health Service Publica-
tion No. 2012, 1969. Reprint by U.S. Environmental Protection
Agency, 1973.
5. Compilation of Air Pollutant Emission Factors, Second Edition.
U.S. Environmental Protection Agency, Office of Air and Water
Programs, Publication No. AP-42. April, 1973.
6. Weinstein, Norman J. and Richard F. Toro. Thermal Processing of
Municipal Solid Waste for Resource and Energy Recovery. Ann Arbor,
Michigan: Ann Arbor Science Publishers, Inc., 1976.
7. Manual of Disposal of Refinery Wastes, Chapter 12, Electrostatic
Precipitators. American Petroleum Institute, Publication No. 931.
Washington, B.C., June 1974.
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TECHNiCAL REPORT DATA
". zTORS
b.lD6NTIFIERS/OPEN ENDED TERMS C. CO3ATI Flcld/CrOUp
Refuse Disposal Incinerators
Compliance Status
Emission Limitations
13B
14D
Release Unlimited
19 SECURITY CLASS (Will KcfOr
-..unclassified
30 SGCURlTY CLASS (flllt pa^l
unclassified
31. NO Or PAL!£5
I ''A Fun" UXO 1 <»./j/
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