INCINERATOR
DESIGN
AND OPERATION

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   Reprinted by U.S.  Environmental  Protection  Agency

                                    1973
                    Public Health Service Publication No. 2012
               Library of Congress Catalog Caid No. 71-607217
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402
                   Price $1.25 domestic postpaid or $1 GPO Bookstore

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                                   FOREWORD
INCINERATION  is a major method of solid
waste processing in the United States today.
Over  the  past  several decades  incinerator
technology   has   been  developed   largely
independently by industry, large institutions,
and  municipal  and  county  governments.
Independent   development   led   to
nonstandardized   incinerator  design  and
operation,  and the  diversity of regulations,
design,  and management practices  failed  to
accomplish the major purpose of incineration:
Maximum  volume and weight reduction  of
solid wastes without environmental pollution.

  The  creation of the following Guidelines
was conceived as a method of describing the
best in incinerator  technology  in  order  to
further its development. The publication is
the result  of a two-year  effort. The work
included many meetings and numerous drafts

Members of the panel were:

            Ralph J. Black, Chairman
            Director, Office of Information
            Bureau of Solid Waste
              Management
            Rockville, Maryland
            Frank R. Bowerman
            Group Vice President
            Zurn Industries
            Los Angeles, California

            Richard B. Engdahl
            Mechanical Engineering
              Department
            Columbus Laboratories
            Battelle Memorial Institute
            Columbus, Ohio
  to  synthesize   published  materials   and
  information newly-written by both the staff
  and the panel members. The diversity of the
  incinerator  design  and  operating  practices,
  mentioned above, resulted in very divergent
  views   that  had  to  be  brought  toward
  concensus wherever possible. The final views
  expressed   in    the   Guidelines   are  the
  responsibility  of the Bureau of Solid Waste
  Management and the authors,  who  worked
  hard to state as fairly as possible the results of
  the long  study.  In  the absence  of firm
  technical data,  this  publication (SW—13ts)
  describes    desirable   performance
  characteristics  for  present-day  incinerators,
  the process of incineration, and the "state of
  the art." The title represents this combined
  approach. The  Bureau intends  to review and
  revise  the Guidelines at  appropriate intervals
  to reflect the latest incinerator technology.
Joseph F. Malina, Jr.
Associate Professor of Civil
  Engineering
Environmental Health Engineering
University of Texas
Austin, Texas

Abraham Michaels
Consulting Engineer
Philadelphia, Pennsylvania

Melbourne Noel
Chief Engineer
Department of Streets and
  Sanitation
Chicago, Illinois
                                           in

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            Joseph Frankel
            Consulting Engineer
            New York, New York

            Herbert C. Johnson
            Senior Air Pollution Engineer
            Bay Area Air Pollution Control
              District
            San Francisco,-California

            Elmer R. Kaiser
            Project Director, Senior
              Research Scientist
            Department of Chemical
              Engineering
             School of Engineering and
              Science
            New York University
John Grady Phelps
Director, Department of Sanitation
Miami, Florida

Casimir A. Rogus
Consulting Engineer
Bay side, New York

Robert J. Schoenberger
Department of Environmental
  Engineering and Science
Drexel Institute of Technology
Philadelphia, Pennsylvania

Morton Sterling
Director of Wayne County Air
  Pollution Control Division
Detroit, Michigan
                         Alan B. Walker
                         Director of Research and Development
                         Research Cottrell, Inc.
                         Bound Brook, New Jersey
  Other staff members of the Bureau of Solid
Waste  Management actively contributing to
this  document included  M. DeVon  Bogue,
Richard W.  Eldredge, Charles  W. Reid, Jr.,
and John B. Wheeler.
  The  Guidelines   were   reviewed  by  the
American  Society  of Mechanical Engineers,
the American Society of Civil  Engineers, the
American   Public  Works  Association,  the
American  Public  Health  Association,  the
Consulting    Engineers   Association,   the
Incinerator Institute of America, the National
Solid Wastes  Management Association, the
U.S.  Department of Health, Education, and
Welfare's  National Air  Pollution  Control
Administration,  the  Bureau  of Mines  and
Federal   Water  Pollution   Control
Administration of the U.S. Department of the
Interior,  and  those  State  agencies  with
planning  grants from the  Bureau of Solid
Waste Management. The Bureau is grateful for
the  time and  effort  contributed  by panel
members   and   these   groups   to   the
development of the Guidelines.
  We hope that planners, designers, operators,
and government  officials will  apply these
guidelines to overcome poor performance of
existing  incinerators  and  that  they  will
recognize the  need  for  effective  pollution
control  equipment. This  publication should
also create an awareness of the need for  new
incinerators    of   improved    design   and
performance.

  -RICHARD D. VAUGHAN, Director
  Bureau of Solid Waste Management
                                          IV

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                       CONTENTS
 Chapter                                               Page

  I       INCINERATION:    A  VOLUME  REDUCTION
          PROCESS                                       1

 II       BASIC DATA FOR DESIGN                       3
             Regulations
             Population
             Quantities of Solid Waste
             Characteristics of Solid Waste

 III       INCINERATOR COSTS                           8
             Capital Costs
             Operating, Owning, and Financing Costs

 IV       SITE   SELECTION,  PLANT   LAYOUT,   AND
            BUILDING DESIGN                           11
             Site Selection
             Plant Layout
             Building Design
             Plant Exterior

 V       UTILITIES                                    16
             Electrical Power
             Water Requirements
             Sewers
             Communications
             Fuels

 VI       WEIGHING                                    18
             Scale Description
             Operation and Maintenance of Scales

VII       RECEIVING AND HAND LING SOLID WASTE      21
             Tipping Area
             Storage Pit
             Charging Methods
             Charging Hoppers
             Charging Chutes

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 Chapter                                                       Pagc
 VIII        FURNACES AND APPURTENANCES                   26
               Furnace
               Combustion
               Combustion Temperature and Cooling
               Refractories
               Other Aspects

   IX        RECOVERY AND UTILIZATION OF HEAT             38
               Heat Recovery Systems
               Application for Recovered Heat
               Auxiliary Fuel
               Manpower Requirements
               Economics

   X        INSTRUMENTATION AND CONTROLS                 41
               Uses of Instrumentation and Controls
               Controlling the Incinerator Process
               Types  and  Application of Instrumentation and
                Controls
               Operational Problems Involving Instruments
               Future Needs

  XI        INCINERATOR EFFLUENTS AND THEIR CONTROL    46
               Odor, Dust, and Litter
               Residue from Combustion
               Fly Ash
               Process Water

 XII        AIR POLLUTION CONTROL                           51
               Particulate Material
               Gaseous Combustion Products
               Desired Emission Levels
               Methods of Control

XIII       ACCEPTANCE EVALUATION                         62

XIV       SOLID  WASTES  THAT  REQUIRE  SPECIAL
            CONSIDERATION                                  64
              Bulky Solid Waste
              Special Incinerators for Bulky Wastes
              Size Reduction of Bulky Solid Waste
              Hazardous Wastes
              Obnoxious Wastes
              Combined Sewage Sludge-Solid Waste Incineration
              Conclusions
                            VI

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    Chapter                                                     Page
      XV        SALVAGE                                         67

     XVI        OPERATION AND MAINTENANCE                    69
                   Management and Personnel
                   Operation Guides
                   Performance Records
                   Utilization of Recorded Data
                   Maintenance and Repairs

     APPENDIX A   AN    ACCOUNTING    SYSTEM    FOR
                    INCINERATOR OPERATIONS                    73

     APPENDIX B   EXECUTIVE ORDER 11282, MAY 26,1966
                    CONTROL OF AIR POLLUTION ORIGINA-
                    TING FROM  FEDERAL  INSTALLATIONS        91
Mention of commercial products in this publication does not imply endorsement by the U.S. Public Health Service
                                 Vll

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                                         CHAPTER 1
          INCINERATION: A  VOLUME REDUCTION PROCESS
  Incineration  is  a  controlled  combustion
process for burning solid, liquid, or gaseous
combustible wastes to gases and to a residue
containing little or no combustible  material.
In  this  regard,  incineration  is  a  disposal
process  because  incinerated  materials  are
converted to water and gases that are released
to  the atmosphere.  The end  products  of
municipal  incineration,   however,  must  be
disposed of. These end products include the
particulate matter carried by  the gas stream,
incinerator  residue,   siftings,  and   process
water.    Incinerator   residue   consists   of
noncombustible materials such  as metal and
glass  as  well  as combustible  materials not
completely consumed in  the burning process.
  The   advantages   of   incineration   are
numerous,  especially where   land   within
economic  haul  distance  is  unavailable  for
disposal of solid waste by the sanitary landfill
method.   A  well-designed   and   carefully
operated incinerator may  be centrally located
and has  been found  acceptable in industrial
areas  so  that haul time and  distance can  be
shortened. The solid waste  is  reduced  in
weight and volume, and the residue produced
can be nuisance-free and satisfactorily used as
fill   material.   In   a  properly   designed
incinerator, the  operation can be adjusted to
handle solid waste of varying quantity and
character.
  An   incinerator   requires a large capital
investment, and operating  costs  are  higher
than  for sanitary  landfill. Skilled  labor is
required to operate, maintain, and repair the
facility.  Thus  capital and operational costs
must be compared with the costs of alternate
disposal methods, and full consideration must
be given to the effects of the methods on the
community and its neighbors.
  The volume  of municipal solid waste in the
storage pit can be reduced  80 to 90  percent
by incineration.  In the process, usually 98 to
99  percent, by weight,  of the combustible
materials can be converted to  carbon  dioxide
and water vapor.  Total  weight reduction  is
commonly 75  to 80  percent based  on the
weight of the as-charged solid waste, including
moisture,   reduced    to   a   dry    residue.
Compaction  of  residue  results in  further
volume   reduction,   so  that  solid  waste
processed  in   an  incinerator  and  then
compacted in a fill may occupy only  4 to 10
percent of its volume in the storage pit.  A
salvage operation can  further  reduce residue
volume.
  Oversized  or bulky  burnable  wastes (logs,
tree stumps, mattresses, large  furniture, tires,
large signs,  demolition lumber, etc.) usually
are not processed in a municipal incinerator
since they are either too large  to charge, burn
too  slowly,  or  contain  frame  steel  of
dimension  and  shape  that  could foul  grate
operation or the residue removal systems. A
few incinerators include grinding or shredding
equipment  for  reducing  incinerable bulky
items  to  sizes  suitable  for charging. In recent
years, special incinerators have been designed
and constructed to handle portions of bulky,
combustible   solid   wastes    without
pretreatment. '~3  Unless these materials can
be incinerated, their bulk and  abundance will
                                            1

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add  greatly to  the  amount of land necessary
for final disposal. Other discarded large items,
such as washing machines, refrigerators, water
heater  tanks,  stoves,  and  large  auto  parts,
cannot be handled by incineration, and they,
too, add considerable volume to a fill.
  The  potential of incineration  as  a space
conserving  mechanism  can be  demonstrated
by  the  following  comparison:  the volume
requirements  for  final  land  disposal of an
incinerator   residue,    with   the   volume
requirements  for  a sanitary landfill  system
receiving unburned  solid wastes.4  Consider
two identical  samples of solid waste. Both are
free of bulky  solid  waste.  Assume that each
sample is  2,000 Ib and 13.3 cu yd (this is a
bulk density of 5 to 6  Ib per cu ft or roughly
1 50 Ib per cu yd) and is typical of solid waste
at   the    generating   source.
  System 1: Incineration.  Based on the 75 to
80   percent   weight   reduction   mentioned
above,   the  residue   produced   from  the
incinerated waste could be estimated at about
523 Ib. Studies have shown  that incinerator
residue may have a landfill compacted  density
of  2,700  Ib per cu yd.4 The 523-lb  residue
will thus  occupy  about  0.194  cu yd.  The
residue can be calculated as 0.194(100)/13.3
or 1.45 percent of the original volume.
  System  2: Sanitary Landfill.  The 2,000-lb
sample  occupies  13.3  cu  yd.  Compaction
reduces the original volume of  13.3 cu yd to
2.2 cu  yd.  The reduction can be calculated as
2.22(100)/13.3 or 16.6 percent  of the original
volume.
  The  ratio of the remaining volumes of solid
waste  in  the two  systems is  1.45 percent to
16.6 percent, or a ratio of about  11  to 1. The
favorable volume reduction by  incineration is
quite  obvious   for solid waste  that  does not
contain bulky items.
  For  practical purposes, however, we  must
consider  the  disposal  of  bulky  items  and
materials  that  ordinarily are not processed
through   conventional   incinerators.   Such
materials  make up  about  20  percent,  by
volume,  of community  solid  waste  at the
collection point and under good compaction
in a landfill, can be reduced to approximately
half their volume  as  collected. The  volume
conservation  advantage  of the  incineration
system over the landfill system is that of 23.3
percent to 11.16  percent,  or  2.1 to  1  (Table
 1).
                  TABLE 1
  COMPARISON 01- THEORETICAL INCINERATION
  AND SANITARY LANDFILL VOLUME REDUCTION
                RELATIONSHIPS
Original
volume
units
Reduction
factor
Final
volume
units
                         Incineration
                  0.8    X   0.0145
                                        0.0116
Incinerable
 waste
Bulky and non-
 incincrablc waste*   0.2    X   0.5      =   0.1
                                  Total  0.1116
                        Sanitary Landfill
Incinerable
 waste
Bulky and non-
 incincrablc waste
                  0.8    X    0.166

                  0.2    X    0.5
      0.133

      0.1
Total  0.233
   *Nonincincrablc wastes are defined in this study as those
materials that ordinarily are not processed through conven-
tional incinerators.
                REFERENCES

 1. KAISER, E. R. The incineration of bulky  refuse. In
       Proceedings; 1966 National Incinerator Conference,
       New York, May  1-4, 1966. American Society of
       Mechanical Engineers, p. 39-48.
 2. KAISER, E. R. The incineration of bulky refuse. II. In
       Proceedings; 1968 National Incinerator Conference,
       New York, May  5-8, 1968. American Society of
       Mechanical Engineers, p. 129-135.
 3. WINKLER, T.  E.  Discussion  of "The  incineration of
       bulky refuse.  II," by E. R. Kaiser. In Discussions;
       1968 National Incinerator Conference, New York,
       May 5-8,  1968.  American Society  of Mechanical
       Engineers, p. 26.
 4. KAISER,   E.  R.  Refuse  reduction   processes.  In
       Proceedings; the Surgeon General's  conference on
       solid   waste   management   for   Metropolitan
       Washington,   July 19-20, 1967.   Public Health
       Service Publication  No.  1729. Washington, U.S.
       Government Printing Office, 1967. p. 93-104.

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                                      CHAPTER II
                          BASIC DATA FOR DESIGN
  Accurate basic  data are  needed  to  design
successfully.    These   data   include
determination   of   present   and   future
population to  be served and the  quantity,
composition, and characteristics of  the waste
to  be  incinerated.   Air,  land,  and  water
pollution   control   regulations  and  other
constraints must be considered.
  Few   communities   have   sufficient
information  for   designing  an  incinerator.
Local studies are usually needed, therefore, to
gather the  data required for the community
or  region  that   will  be  served  by   the
incinerator.  Population   projections   and
densities and  the  number,  type,  size  and
location   of   industries   and   commercial
establishments  are  usually   available  from
planning agencies, the Chamber of Commerce,
or  other  community organizations.   Useful
records on the  quantity and characteristics of
solid waste being generated may be available
from  the  municipal  agency  responsible  for
solid  waste control. Local stipulations as to
what wastes will be accepted for incineration,
whether  householders  must  separate  their
solid  wastes, and the hours  of incinerator
operation must be considered by the designer.
Some  of  the  basic  factors  that  influence
design are discussed in this chapter.

               Regulations

  Incinerator design  must meet regulations
intended  to preserve the  quality  of  the
environment and  the health and safety of the
operators. Local requirements  include air and
water quality standards, zoning, building and
electrical code stipulations, and occupational
health, safety, and sanitary regulations.
  A  designer  must  consider  existing local,
State,  and  Federal   regulations  and  the
regulations of neighboring communities. He
should also recognize  that  more  stringent
regulations on  air  and water pollution can
reasonably be expected in the future, and the
design should be capable  of meeting  these
higher future standards. To serve as a guide
where  no  local  regulations   exist,   this
publication includes Executive Order 11282,
May  26,  1966,  "Control  of Air  Pollution
Originating from Federal Installations" and
standards   by   the  Secretary  of  Health,
Education, and  Welfare  implementing the
objectives prescribed by the Order (Appendix
B).

                Population

  Determining   the  present  and   future
population to be served has several important
purposes.  An appraisal of population density
aids in locating the incinerator at  the most
economic  site.  Another  important  use of
population data is to estimate the quantity of
wastes to be incinerated and, therefore, the
incinerator   capacity   required   for  the
designated area.
  The population estimates should include the
transient,  commuter, and permanent domestic
population at the  time the  survey  is made,
when the  plant is to be opened, and over the
projected  life of the incinerator (usually 20 to

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40 yr).  In determining the future population
to be served by  the  facility,  the  designer
should  consider  the  possible  inclusion  of
adjoining    developed   areas   within   the
metropolitan  complex   and   the   possible
servicing of new  areas as they develop.
  Standard   techniques   are   available  for
estimating current population. Some correlate
the historical census records with an historical
record  of  population  indicators,   such  as
number of water meters, water consumption,
or other utility  or commercial consumption.
Other methods  relate  community growth to
historical growth of nearby industries or other
communities. Updated population projections
often can be obtained from local, district,
county, or State  planning departments  and
from local utility companies.

          Quantities of Solid Waste

  The quantity of a community's solid waste
will  vary  markedly with the climate, season,
character  of the community,  the extent and
type  of commercial, industrial, institutional,
and  residential  developments as well as the
extent of usage of on-site incinerators  and
food waste grinders.
  Per  Capita  Quantities.  The  continuing
increase   in  the  quantity  of  solid  waste
produced  in the United  States is  attributed
not only to increased population, but also to
increase in  per  capita  generation.  The  wide
spread in  the ranges of solid  waste collected
(Table  2)  points  out  the  need   for  local
studies.
  Weekly  and Seasonal Variations.   Seasonal
fluctuations  occur in the  amount  of  solid
waste  generated  and  collected within  the
community and  must be considered. This can
be done  by plotting weekly waste quantities
averaged over 4-wk periods.' The fluctuations
in waste quantities occur in yearly cycles, the
maximum  quantity almost  always peaking
during the warmer months. Because  of many
influences, the magnitude of fluctuations  is
                 TABLE 2
      PER CAPITA SOLID WASTE COLLECTED
         Type
      Quantity
(Ibs/capita-calendar day)
Residential (domestic)

Commercial (stores, restaurants,
 businesses, etc.)

Incinerable bulky solid wastes
 (furniture, fixtures, brush
 demolition, and construction
 wastes)
      1.5-5.0


      1.0-3.0




      0.3-2.5
significantly different  from one community
to  another.  Factors that influence  variation
are  climate,  weather,  geography,  tourism,
holidays,   consumption   habits,   collection
procedures,  and  community  size.  Four-wk
averages  in  waste  generation   within  a
community  commonly  range  from   ±  10
percent of the average weekly waste quantity;
weekly variation in any  year seldom exceeds
25  percent of the average weekly quantity for
that year.1
  Sizing.  Because  of large daily fluctuations
in  solid  waste  quantities,  an incinerator
should  be  sized  on  the basis of weekly
quantities  of solid  waste to be incinerated.
The storage pit  should be designed  to  handle
daily peaks in quantity.
  One incinerator sizing  method is based on
the  average  weekly  delivery  for the highest
4-wk period  projected for the design  year.
Another method of sizing is based on the use
of a standard frequency diagram using weekly
solid waste quantities and a time period of a
year (Figure 1). With the use of a plot of this
type,  the  incinerator  size is based  on the
weekly solid waste  quantity  that will  be
exceeded a  given percent of the  time during a
year. If the  design was to  be based  on a
weekly quantity that was exceeded 5 percent
of  the  time,  a  weekly solid waste quantity
corresponding   to  95   percent  would  be
selected from the frequency diagram.

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  In sizing an incinerator, the fact should also
be   considered  that   it  will   not  operate
continuously  over the  planned period.  Past
experience indicates that incinerators require
about  15  percent  downtime for repairs and
maintenance.

        Characteristics of Solid Waste

  The  design  of  the  incinerator  system,
including   furnace  chamber,   grates,  feed
mechanisms,   and  other   parts,  will  vary
because of differing waste characteristics and
amounts.  A plant to  handle only  household
waste  will differ from one  that handles food
waste  from stores and restaurants or from one
that   handles   only    dry,  high-heat-value
industrial  waste. The  significant variations in
composition  that will  actually occur  in a
particular community must be determined.
  Not  only has  the  per capita quantity of
solid waste generated  across the United States
been increasing  yearly, but the chemical and
physical  properties  have  been changing as
well.   The   moisture   content   has   been
decreasing   with   diminishing   household
garbage,   and  the ash  content  has  been
decreasing as less  coal is  used for heating.
Moreover, combustible content and heat value
have  been increasing, principally because  of
the ever larger use  of paper and plastics. The
net result has been to  increase heat value  of
the  "as  delivered" solid  waste to  such  an
extent that greater furnace volumes and more
combustion air  are required to maintain the
rated burning capacity of an incinerator.
  Composition   of   Residential   Solid
Waste.  Analysis of a composite of residential
solid  waste shows  a range  of percentages for
material  types  (Table  3). As collected at the
source in receptacles or piles, residential solid
waste generally  weighs  between  100 and 300
Ib per cu yd  and averages 150 Ib per cu yd.  In
the collection truck, solid  waste is commonly
compressed from 350 to 700 Ib per cu yd.  In
the incinerator  pit, the weight of the waste
generally ranges from 300 to  550 Ib per  cu
yd.
  Bulky   Solid   Waste.  Unless   special
provisions are made, combustible bulky items
such  as furniture, fixtures, and waste lumber
present   an    operational   problem  when
delivered to an incinerator. As already noted,
exclusive  of   junked   automobiles   and
                    5.2     10.4    15.6     20.8    26.0     312    364     416    46.8    52.0

                                   NUMBER OF WEEKS VALUE IS NOT EXCEEDED
                           20     30     40     50     60     70

                                   PERCENT OF YEAR VALUE IS NOT EXCEEDED
                                                                  80     90
    Figure 1.  I-requency diagram of cumulative weekly solid waste quantities delivered for disposal during a year. At the
 asterisk, 95 percent of the year (49 of 52 wk) the quantity of solid waste did not exceed 15 percent above  the average
 yearly mean.

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                 TABLE 3
     RANGE [N COMPOSITION OF RESIDENTIAL
         SOLID WASTES IN 21 U.S. CITIES
                   Percent composition by net weight
Component
Food waste
Garden waste
Paper products
Metals
Glass and Ceramics
Plastics, rubber.
and leather
Textiles
Wood
Rock, dirt, ash, etc.
Low
0.8
0.3
13.0
6.6
3.7

1.6
1.4
0.4
0.2
High
36.0
33.3
62.0
14.5
23.2

5.8
7.8
7.5
12.5
Average
18.2
7.9
43.8
9.1
9.0

3.0
2.7
2.5
3.7
   "Unpublished  data, Division of  Technical Operations,
Bureau of Solid Waste Management. Values were determined
from  data  taken at  21 cities in continental United States
between 1966 and 1969.

demolition  waste,   nonincinerable   waste
amounts  to about 20  percent by volume of
total community solid waste.  Of this, about
50 percent is  combustible material. Separate
collection   service   has  frequently   been
employed  to reduce the number of such items
delivered   to  the  incinerator. Recently   the
trend has been to design incinerators capable
of processing almost everything.
  Shredders and grinders are now being used
at   some   incinerators,   and   specialized
incinerators have been used  for  bulky waste
alone.2'3    The    operational   problems
encountered in handling bulky solid waste are
discussed in Chapter XIV
  Other Characteristics. The heat values and
the  proximate and  ultimate  analyses  of  the
solid waste as  delivered  to  the incinerator
(Table 4)  are  used in  calculating heat release
rates, combustion and excess air volume, grate
area, draft,  and  other factors.  Proximate
analysis  is the  determination of  moisture,
volatile   matter,  fixed   carbon,  and   ash
expressed  as percentages of  total weight  of
the   sample.    Ultimate  analysis  is   the
determination   of   moisture  content,
noncombustibles, and the carbon, hydrogen,
oxygen, nitrogen, and sulfur content.
  Data  on  the proximate  analysis, ultimate
analysis, and  heat  values of individual waste
components such  as  newspaper,  cardboard,
grass, meat scraps, fruit peelings,  etc., have
been  published.4 These data can be  used to
estimate proximate analysis, ultimate analysis,
and  heat value once the composition (% by
weight) of a waste is determined.
  The   methodology   for   obtaining   a
representative  sample  of solid waste  and its
analysis  has been described by the American
Public  Works  Association.5   Oxygen  bomb
calorimetry for  determining the amount of
heat liberated  from solid materials and from
liquids has been described.6
  The ultimate analysis provides a means for a
rational  approach  to  furnace  design  and is
required for a complete materials balance of
incoming and  outgoing material.  Significant
variations  in   these values  can  occur  with
seasonal and   climatic change.  Variation in
moisture   is    particularly    critical;   the
maximum,  mean,  and  minimum  moisture
value should,  therefore,  be  determined to
provide  a range for best, average, and worst
conditions.  If these  varying  conditions are

                 TABLE 4
  PHYSICAL AND CHEMICAL CHARACTERISTICS OF
          INCINERATOR SOLID WASTE*
Constituents
Proximate analysis
Moisture.
Volatile matter.
Fixed carbon .
Noncombustibles
Ultimate analysis
Moisture
Carbon
Oxygen
Hydrogen .
Nitrogen
Sulfur .
Noncombustibles
Percent by weight (as received)

15-35
50-65
3- 9
15-25

15-35
15-30
12-24
2- 5
0.2-1.0
0.02-0.1
15-25
Higher heating value
Btu per Ib (as received)
  3,000-6,000
   *Principally residential-commercial waste excluding bulky
waste.

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recognized, the incinerator can be designed to
operate under them.
  Heat value is one important characteristic ot
solid waste needed for incinerator design. The
term  "heat  value"  can be  used  in several
different ways.  One way,  the "higher heat"
value  or  "gross  heat"  value,  is the  total
amount  of heat released per unit weight of
material that is burned.  The higher heat value
is  determined by  oxygen  bomb  calorimeter
measurement, although it  can  be estimated
from  chemical  composition  of  the sample
material if known. Another way of expressing
heat value is called "net" or "low" heat value.
To determine this value,  the  latent  heat of
vaporization of all moisture resulting from the
combustion  process  is  subtracted from  the
high heat value.
  As mentioned above, the long-term trend in
the   United   States  has  been  for   the
combustible  fraction (principally  dry paper
and  plastics)  of  municipal  solid waste  to
increase   and  for  the moisture  content  to
decrease  (mainly  because  of the  decrease in
wet  food waste).  Hence,  the  heat value  of
waste  as received  at  the  incinerator is rising.
At  present, incinerator  designers  are  using
gross heat  values ranging from 3,000 to 6,000
Btu  per Ib based  on waste as received. The
present  trend  indicates  that  heat values  of
incinerator solid  waste will increase by 500
Btu per Ib  by 1980.
               REFERENCES

1.  Bureau of Solid Waste Management. Unpublished data
       (SW-lOts).
2.  KAISER, E.  R. The  incineration of bulky refuse. In
       Proceedings;   1966  National   Incineration
       Conference, New York, May 1-4,  1966. American
       Society of Mechanical Engineers, p. 39-48.
3.  KAISER, E. R. The incineration of bulky refuse. II. In
       Proceedings; 1968 National Incinerator Conference,
       New York, May  5-8,  1968. American Society of
       Mechanical Engineers, p. 129-135.
4.  KAISER, E. R. Chemical analyses of refuse components.
       In  Proceedings;   1966   National   Incinerator
       Conference, New York. May 1-4,  1966. American
       Society of Mechanical Engineers, p. 84-88.
5.  American Public  Works  Association.  Municipal refuse
       disposal.  2d  ed. Chicago,  Public Administration
       Service, 1966. 528 p.
6.  Par Instrument Company. Oxygen bomb calorimetry and
       combustion  methods.  Technical Manual No.  130.
       Moline, III, 1960. 56 p.

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                                      CHAPTER III
                              INCINERATOR  COSTS
  Incinerator costs are divided between those
related  to ownership and  those  related  to
operation. Ownership costs derive from the
capital  costs   of  financing  the  incinerator
construction and are usually paid off through
depreciation  and  interest charges.  Operating
costs include  the  direct and indirect costs of
operating and maintaining  the plants.  This
chapter presents costs for existing municipal
incinerators and  outlines the  major  factors
that influence costs.
  Knowledge  of  capital  costs  of existing
incinerators is of interest  as  the basis for
understanding,  at  the  planning stage,  how
much money  is  involved in constructing  an
incinerator.    It   is   also   prerequisite   to
determining total costs. These  total costs of
ownership and operation  are  necessary  to
compare different incinerators and to evaluate
incineration  with  other  methods  of  solid
waste  disposal.  The  data  included  in this
chapter  present  national averages of these
costs and can  be used for general comparisons
or planning purposes.
  Although  costs  are necessary  in comparing
the  operation  of different  incinerators, the
primary  use  of  cost  data  is  for effective
management.  An  example  of an  accounting
system  that  may aid  in obtaining  data  is
included in Appendix A.


                Capital Costs
Community  Solid  Waste  Practices data. The
capital   costs  are  reported   as   the   1966
estimated replacement costs and  include  the
costs of buildings, facilities, and engineering,
but not land.
                                                        CAPITAL COST PER TON (THOUSANDS OF DOLLARS)
  The   Capital   COStS   Ol   170   municipal     Figure 2. Cumulative frequency diagram of capital costs
incinerators  were  obtained  from  the  US    for 170 municipal incinerators in $1,000 increments. At the
        IT  i  i   r                          "   asterisk,  62 percent  of the incinerators have  capital  costs
        Health  Service  National  Survey  of   below $6,1 so per ton (24-hr design capacity).

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       IOO
     Q
     lij
     Q
       90
       SO
       70
     O
     o
     p 6O
     <
     it
     UJ
     Q.
     O
       50
       40
     UJ
     cr
     Q:
     ^
     o
     o
     o
     tu
     o
     Q:
       30
20
        10
               IO
                      20
                             30
   Figure
costs  for
         OPERATING COST
        (DOLLARS PER TON)

 3.  Cumulative frequency  diagram of operating
  78  municipal  incinerators  in dollar-per-ton
increments. At the asterisk, 73 percent of the incinerators
have  operating  costs below  S5.00 per ton  solid waste
received.
  These data indicate  an average capital cost
of municipal incinerators at about $6,150 per
ton (24-hr design capacity). (Example: capital
cost of $600,000 -H 100-ton-per-day capacity
= $6,000 per ton.)  Sixty-two  percent of the
incinerators studied cost less than $6,150 per
ton (Figure 2). Fifteen plants reported capital
costs above  $11,000  per ton. The highest
capital cost,  reported  by only  one  plant, was
$30,000 per ton.
  Some of the  major equipment  cost items
included  in  capital costs are  scales,  cranes,
furnaces,   blowers,  air  pollution  control
devices, process  waste treatment and recycling
equipment,    residue   removal   systems,
instrumentation,   waste   heat   recovery
equipment,  steam  distribution equipment,
and   flue  and  duct   equipment.  Major
construction  items  on the structure include
building,  ramps,  tipping  area, storage  pit,
refuse hoppers,  offices,  employee facilities,
piping,  and  chimney.  Miscellaneous  items
under capital cost  include  site preparation,
excavation, foundation preparation, roadway
and   sidewalks,  landscaping  and seeding,
furniture   and   fixtures,   machine    shop
equipment, and  tools.
  Fly-ash control equipment has, in the  past,
amounted to about 3  percent of the  total
capital  cost  of municipal  incinerators.1 To
achieve particulate removal as required by the
new and  more stringent air pollution control
regulations, the  cost  of control  equipment
will  now  range  from 8 to 10  percent of the
total capital cost.
  Capital  cost components  and their relative
importance  may  be  grouped  as follows:
furnaces  and  appurtenences (55%  to 65%);
building (20% to  30%);  air pollution control
equipment (8% to 10%); miscellaneous (7% to
13%).


        Operating and Owning Costs

  The   1968  National   Survey   data   also
provided  information  on operating costs of

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municipal incinerators. Since the  calculation
of the costs per ton of solid waste processed is
dependent  on weighing  the  material,  this
discussion is limited to the facilities (78) that
actually weighed  their  incoming solid waste.
  The Survey data on operating costs gave an
average   cost   of    operating   municipal
incinerators   of  S5.00  per  ton  of  refuse
processed.  Seventy-three   percent  of  the
incinerators studied had operating costs below
S5.00 per  ton (Figure 3).  Four  of the  78
plants reported operating costs above $10 per
ton.
  The  wide  variation  in  operating  costs
resulted  partly  from  differences   in   the
amount   and   types   of  pollution   control
equipment,  labor  rates,  cost  of  utilities,
residue  disposal   costs,   and  amounts   of
automation.  Reported operating costs are also
influenced by  the fact  that  some  cost  items
are  not  included  when  calculating the total
operating  cost.  For   example,   for  many
incinerators,    the    cost  of   utilities,
administration,  or  employee fringe  benefits
are  not included in operating costs.
  Ownership costs include  the financing costs
associated with the depreciation and interest
of the facility. The  costs for depreciation and
interest  have  been  commonly given  to  be
between $1.00  and  $2.00 per ton.  In practice
the   actual   costs   can   vary   significantly
depending on factors such as utilization rate,
estimated life, and  interest rates. Total costs
                  TABLE 5
       TYPICAL INCINERATOR COST CENTERS
Operating costs
Labor (operatingand maintenance)
  Salaries
  Vacation and holiday pay
  Sick and injury pay
  Training
  E-'ringe benefits
  Pensions
Utilities
  Water
  Electricity
  Gas or fuel oil
Miscellaneous charges
  Materials and supplies
  Contract work
Overhead
  Management
  Charges from other administrative departments

Ownership costs
Depreciation
Interest
of  ownership and operation can  be  stated
either for a time period or for the quantity of
wastes incinerated, for example, annual  cost
or cost per ton (Table 5).

                REFERENCE

1.  American Public  Works Association.  Municipal refuse
       disposal.  2d  ed. Chicago,  Public Administration
       Service, 1966. p. 145.
                                             10

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                                      CHAPTER IV
   SITE  SELECTION, PLANT  LAYOUT, AND  BUILDING  DESIGN
  Proper location of the incinerator enhances
acceptance  by  the  public  and  results  in
economies in waste collection. A well-planned
physical   layout  facilitates  efficient  and
economic incinerator operation. Good design
and   selection   of   appropriate   building
materials promotes a pleasing appearance and
minimizes housekeeping and maintenance.

               Site Selection
  Public  Acceptance.  Public acceptance is a
most  important consideration in selecting  an
incinerator site. A few suggestions for gaining
public acceptance follow.
  1.   Choose  a  site where  construction can
conform   with   existing   and   planned
neighborhood character. In general, industrial
and  commercial  areas  are  more compatible
with  incinerators  than residential areas. An
incinerator plant is usually classed as heavy
industry,  and the evaluation of its location
should reflect this. Too frequently the vacant
land  surrounding  an  incinerator  is   later
developed  for residential or other restricted
use, which creates conflict. To avoid potential
conflict,  the undeveloped,  surrounding  land
should be zoned for industrial use.
  2.   Avoid choosing a  site that may conflict
with other public buildings.  The noise, lights,
and  24-hr workday of  normal incinerator
operation preclude locating it near a hospital,
and  heavy  truck traffic makes incinerator
location near schools undesirable.
  Centralized  public works operations  are
desirable.  Often an  incinerator  plant can  be
advantageously   located   near  a   sewage
treatment plant so that technical services may
be  shared.  There  may  be  ecomomies in
locating  the incinerator near a garage where
vehicle repair  facilities and  personnel can be
shared.
  3.  Where   conflict   with   neighborhood
character is unavoidable the screening effects
of  a  wall or  planting  can reduce  adverse
effects  and gain  public  acceptance.  Good
architectural design is itself a major asset in
overcoming   potential   neighborhood
objection.
  4.  Institute  an effective public relations
program. Before full site and design decisions
are made,  proposals and  plans should  be
presented through the press and for discussion
at  public  meetings.  This  would  serve  to
demonstrate   management   response   to
community  desires  and  a  capability for
operating an  acceptable facility. Presentation
of  alternatives   along  with   rationale  for
incineration may  be supported  by  graphic
examples  and  site  visits   to  successfully
operating facilities.
  Site   Suitability.   Factors   important  to
design, but generally not of concern to the
public,    are   foundation   conditions,
topography, availability of  utilities,  building
restrictions,   drainage,    and  meteorologic
conditions.
  Soil  and rock  formations  determine the
type of  foundation  required to  support the
heavy,  concentrated load  of an incinerator
structure.  Failure to  accurately determine
foundation conditions and design  to them can
                                            11

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 result  in   expensive   modifications  during
 construction   and.   in   certain   cases,
 abandonment  of the  site  with its partially
 completed structure. Groundwater conditions
 also affect design and cost.
  Topography  and meteorological  conditions
 must be  considered in the location and the
 design of the incinerator. A flat site is apt to
 require a  ramp for access to the tipping floor,
 whereas a hillside  site  can provide access at
 various ground levels.  Topography can  also
 ease  or hinder the dispersion  of gases  and
 particulates by the local atmosphere.  This
 aspect  of  plant  location is  complex  and
 requires the assistance of  a meteorologist or
 air   pollution  control  specialist,  who  can
 determine   the  best  stack  height for  the
 dispersion    of  gases.   Stack   height
 determination   requires   consideration   of
 topography and legal  restrictions, such as
 those   from  Federal  Aeronautics  Agency
 regulations, local  building regulations,  and
 zoning.
  Availability  of  public  utilities  may be  a
 governing   factor  in  site selection,  since
 electricity, gas, water supply, sewage disposal,
 and  process water disposal are essential to the
 incinerator  process. Fuel such  as  gas or oil
 may  be required at some installations as an
 auxiliary heat  source for  the furnaces or as
 building heat. Communication facilities must
 be available for fire and safety control and for
 coordinating operations.
  As in  the development of any industrial site,
 effective drainage of surface waters must be
 an integral part of design. The site should not
 be  selected in  an  area subject to flooding
 unless the facility can be protected  and access
 remains available during high water.
  Traffic  Consideration.   The  ideal location
 for  an  incinerator is  at  the center  of  the
 traffic pattern  produced by the contributing
 collection vehicles.  A  major argument already
made for  incineration  in comparison with
land disposal was that incineration can reduce
 the  time  and  cost of  collection  haul. This
requires  that   the  incinerator  be  centrally
located.  This  is  not always  feasible  tor  a
variety   of  reasons.  For   example,  future
growth and its effects on the collection source
must be considered.
  A  large plant may have literally hundreds of
vehicles  delivering solid  waste  in  relatively
short time intervals. Because of heavy traffic,
the  plant must  have  adequate  access  to
preclude safety  hazards in  the streets of the
area. Special access  roads  may  have  to  be
provided  so  that  the trucks  avoid  heavily
traveled  highways.  Special  consideration also
must be given to traffic impediments such as
bridges with low  weight  limits, restrictive
heights of overpasses,  narrow pavements, and
railroad  grade  crossings with high  volume
traffic.  A location  that   avoids  commuter
traffic is also preferred. Thus,  a plant located
near the edge of the participating community
but readily accessible by freeways or beltways
may be better than one centrally located. The
same traffic  considerations apply to residue
disposal. On-site disposal is often not possible;
therefore,   incinerator   residue   and
nonburnables must be trucked  to a landfill.

                Plant Layout

  An incinerator plant layout should promote
ease,  simplicity  and  economy  of operation,
and  maintenance. There should  be adequate
room  for  all  parts  of the  operation.  The
structure   should    harmonize   with  the
surrounding  neighborhood  and should be so
oriented  that unsightly parts of the  building
and  operation (such as receiving and storage)
are  not   visible  to  the  public.  In  certain
climates,  it  is  advantageous  to orient the
receiving  area  on  the leeward  side  of the
prevailing  wind. The  on-site  road   pattern
should  allow  ready  access  to  scales  and
receiving  area  and  an  easy  exit;  one-way
traffic is most desirable; sharp turns and blind
spots should  be avoided; and a large parking
apron  should   be   provided   outside  the
receiving area to avoid congestion during peak
receiving hours.
                                            12

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  Adequate drainage is necessary  for surface
waters.    Incinerator    operation   requires
periodic hosing of tipping floor, vehicle wash
areas, parking aprons,  and ramps. The paving
should be sloped and contain adequately sized
and   strategically   placed   drains.  This  is
particularly critical in  cold climates where ice
formation could interfere with operations.
  Maintenance and storage  of trucks may be
inside  the  incinerator building or  on  the
grounds,   but these areas  must  be  located
where  they will not hamper the operation of
the incinerator.

              Building Design

  The  incinerator  should   be  aesthetically
pleasing   and  should   be   constructed   of
durable, high-quality materials and fixtures to
reduce  maintenance.  Materials  requiring  a
minimum of painting  or resurfacing, such as
concrete,   tile,  and  noncorrosive  metals,
should be used. Surfaces that require painting
should have  a dense, durable finish.  Corners
and   bases   can   be  coved   to   reduce
accumulation of   debris  and  allow easier
cleaning.  Where  possible,  piping  and duct
work should be enclosed.
  Personnel Facilities.   Adequate facilities for
incinerator  personnel  are more a  matter  of
convenience  and   may  well represent  the
difference between a working situation that is
conducive  to  efficiency and  cleanliness  as
opposed  to one that may create an indifferent
and  inefficient work  crew. A  clean locker
room  is  needed, with   'adequate  toilet,
lavatory, and shower facilities. Lockers should
have  space for storing hard hats,  rain and
winter gear, and  a full change of clothing.
Sanitary   facilities  should  be  provided  for
women who may visit  or be employed at the
plant.
  Lunchroom  facilities   should   also   be
provided  along with   a sink  and  suitable
outlets for coffee percolators. Drinking water
should be available on every floor and within
200  ft of employee stations. The lunchroom,
locker room, shower, and  toilet areas should
be well lighted and kept clean  at all times to
encourage  habits  of  cleanliness  by   the
workman.  It  is  often  desirable to  provide
washroom  facilities  convenient to  collection
personnel, weighmasters, and others.
  Control Room.  Many large incinerators are
now being built with glassed-in control rooms
so located  that the incinerator superintendent
or shift foreman can readily observe various
operations. Because  all  areas of the plant or
operating conditions within furnaces cannot
be observed from one location, closed-circuit
television  is  used in  some instances.  The
importance of the glassed-in area (ventilated
and air conditioned) is not merely to provide
comfort to the superintendent and foreman,
but to protect delicate  recording instruments
from  dust  and to minimize the noise level in
an area  where telephones are  used.  Written
records  are  also better  maintained  in  an
isolated control room area. The control room
should  be suitably  equipped  with  remote
reading  and   recording   instruments  that
provide   supervising  personnel  with   the
information    necessary   to   adjust   the
incinerator operation if it is not performing
suitably.
  Administrative  Offices   and  Conference
Room.   In  the   larger incinerator   plants,
sometimes the superintendent, foremen, and
clerical workers  need  an  office to conduct
necessary administrative activities.  Attractive
decor   and air  conditioning  will  improve
morale  and efficiency. Smaller  incinerators
may   effectively  combine   the  operating
control  room  with  space  for  administrative
activities.
  At larger plants, a conference room for staff
briefings,  safety  discussions,  and  training
purposes is a worthwhile investment.
  Weighmaster's   Office.  The  weighing
activities  may  be conducted  alongside  the
access road outside the  incinerator plant or at
the entrance  to the  turning and tipping area
within  the plant  proper.  In either instance,
the weighmaster should have  a facility  with
                                            13

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 ample glassed area to observe the movement
 of weigh scale  traffic. He should have  ready
 means  of  communicating  with  the driver,
 handling  credit   cards,   or  making   cash
 transactions.
   Maintenance    and    Repair
 Facilities.   Regardless  of the  size   of  the
 incinerator,   storage   space  for  electrical,
 mechanical,   and  refractory  parts   and  an
 enclosed  area where  repair and  subassembly
 may be performed must be provided.  For very
 large plants, separately maintained storerooms
 for parts, electric shops, mechanical shops, and
 enclosed refractory storage facilities should be
 included. Where  a large  municipality  has a
 number  of incinerators,  central maintenance
 and repair  facilities for major activities may
 prove  economical.  There  should be storage
 facilities for such  items as lawn mowers, skip
 loaders,   mechanical  sweepers,  refractories,
 pipes,  insulation   material,  and  the  various
 chemicals required for insect and other pest
 control.
   Laboratory.  The incinerator  must be  so
 operated   that   the   environment   is  not
 polluted. Federal, State, and local regulations
 are becoming more restrictive. Surveillance of
 the water quality of incinerator effluent is
 needed to  ensure pollution  control,  and a
 small   laboratory   and   testing  equipment
 should   be   provided   for  this   purpose.
 Municipalities with several incinerators should
 consider a centralized  laboratory facility.
  Interior   Lighting.  At   many   municipal
 incinerators  the  interior  lighting   is  poor.
 Recommended lighting standards for various
 industrial  operations   are  published  by  the
 illuminating    Engineering   Society,1   and
 lighting  standards  exist  for  certain  tasks
 similar  to  those  performed  at  incinerators
 (Table 6).
               Plant Exterior

  Roadways,   Sidewalks,    and   Parking
Areas.  In  designing  the  roads   providing
                  TABLE 6
      LIGHTING STANDARDS APPLICABLE AT
                INCINERATORS
Office and industrial tasks
Foot-candles
  on task
Loading and trucking                        20

Corridors, elevators, stairways .                20

Rough, easy assembly work                   30

Reading high-contrast or well-printed
 material, tasks and areas not involving
 critical or prolonged seeing such as
 conferences, interviews, inactive files,
 and washroom .                           30

Medium bench and machine work, rough
 grinding, medium buffing and polishing,
 difficult inspection                       100

Regular office work, reading good reproductions,
 reading or transcribing hand writing
 in hard pencil or poor paper, active
 filing, indexing references,
 mail  sorting                            100
ingress to  an incinerator site, consideration
must  be  given to peak loading  periods  and
types   of  vehicles   that  may  utilize  the
incinerator.   Where   possible,  the  roadway
system should be  built  so  that the traffic
flows  only in one direction, thus providing
only one entrance and one exit. Arrangements
must be made for obtaining truck tare weights
without interfering with one-way traffic flow.
This  is possible  even where  scales are used,
provided  the  trucks  being serviced all  have
established  tare   weights.  When   transient
traffic is being weighed, so that a "weighout"
is  necessary,  a   roadway may  be  provided
within  the  site that will  allow the trucks to
return  across  the   scale  for   the   second
weighing  in the same direction as the normal
flow   of  traffic.   All  roadways  should  be
sufficiently wide  to permit the passage of one
vehicle past another in  the event  that a truck
is stalled. Road grades should be suited to the
traffic operating on the grades. In general, the
grades  for short-distance  truck travel  should
                                             14

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not  exceed 7 percent uphill and 10  percent
downhill. Pavements should  be hard surfaced,
all  weather, and  designed  for heavy loads.
Curbing, posts, or guardrails should be used to
confine traffic to roadways.
  Incinerator plants should  be provided with
sufficient sidewalks to ensure that visitors and
plant personnel will be  able  to  walk safely
about the premises without  being endangered
by vehicular traffic.
  Parking areas are generally divided into two
categories: (1)  parking for administrative and
operating personnel, visitors,  and temporary
parking for collection vehicles, (2) parking for
overnight storage of collection  vehicles and
for  equipment  used  at  the incinerator site
such as mobile sweepers. In  areas with severe
winters,  parking facilities inside heated garage
areas   are   desirable   to   permit  proper
maintenance, cleaning, and protection of the
collection vehicles.
  Landscaping.  Perimeter planting around an
incinerator  site presents a pleasing appearance
and reduces the  noise  of  the  truck traffic
from within  the  property.   For  maximum
benefit    and   to   further   enhance    the
appearance, trees and shrubbery can be placed
outside the fencing. Provisions must be made
in  advance for  adequate watering and  for
access so  that  periodic trimmings may  be
performed  without unreasonable  expense.
Built-in   sprinkling  systems  should    be
considered for lawn and shrub areas.
  Fencing   and   Lighting.  Where    the
incinerator plant is located in  an area subject
to vandalism, peripheral fencing is desirable
with  a  minimum  height of 6 ft with three
strands   of  barbed  wire on a  45° angle
projection  at the top. Such fences should be
constructed  of low-maintenance,  rustproof
metal.  Gates should be similar  in design and
provided with  sturdy locks. The substitution
of peripheral plants for fencing  is usually not
desirable, since most hedges can  be penetrated
by intruders.
  External  lights placed  on  the incinerator
building   are   adequate   to   light   most
incinerator sites. If the building lights should
prove   objectionable   to  the   surrounding
neighborhood,  perimeter  lights  on  stands
directed towards the incinerator plant may be
preferable.   Light  stands  should  also  be
provided along the on-site roadways used by
collection and incinerator vehicles.
  Traffic Control.  Signs for the control of
traffic  should  be  simple  and  the  lettering
should  be  large.  Where one-way control of
traffic  is  desired,  the  entrances  and  exits
should  be  clearly indicated.  Proper design of
roadways  and directional markings on the
pavements, such  as arrows  and  centerline
striping, will lessen the need for traffic  signs.
A stop sign or signal placed at the entrance to
the  scale  is essential.  At very  large plants,
electrically controlled signals operated by the
weighmaster may be desirable to route traffic.
Signs should be informative and clearly visible
so that visitors to the plant, as well as routine
users,  will  have  no  difficulty  entering and
leaving the plant.


               REFERENCE
1.  Illuminating Engineering Society. IES lighting handbook;
       the standard lighting guide. New York. 1959 [1156
       P-]
                                             15

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                                      CHAPTER V
                                     UTILITIES
  For   efficient   operation,  a   municipal
incinerator  requires certain  utility  services,
which  include: (1)  electricity for  power and
lighting; (2) potable water for plant personnel
and  suitable  process  water for  spraying,
heating, quenching, cooling, and fire fighting;
(3) telephone service; (4) sewerage systems
for handling process  waste and sewage, and
storm  sewers  for  drainage;  (5)  fuel for
heating,   hot  water,   auxiliary  heat  for
incineration,   and  possible  laboratory  use.
Each   of   these  utilities  supplied  to  the
incinerator   site   must   be  metered   and
distributed safely and efficiently to all  points
of usage at the site.
  With increasing  incinerator capacities and
with   increasing   use    of  sophisticated
equipment and devices, more utility services
will be required. The cost of providing these
utilities depends on  the  plant  design  and
mode  of  operation and may reasonably be
expected  to  range from $0.10 to $1.00 per
ton of waste processed.
              Electric Power

  With   few   exceptions,   utilization   of
incinerator  waste  heat to generate electric
power is not practiced in the United States.
The incinerator's electrical power is obtained
from other sources.
  Electric  power requirements vary with the
degree  of mechanization and  the use  of
equipment. Common examples of equipment
requiring  electricity  are  induced draft  fans,
forced-air  fans,  pumps,  cranes,  hoists, air
pollution  control  devices, and grate-driving
mechanisms.  Allowance  for  future electrical
needs  should  be  included  in  planning and
sizing the electrical distribution systems. For
some   facilities,  electric  power can  cost  as
much as $0.75 per ton of waste incinerated.
  The  voltage for  the   lighting  system  is
usually   110  volt, although  higher  voltage
fluorescent  and   mercury-vapor  lamps  are
becoming widely used. The latter types have
higher   first   cost,   but   provide    lower
maintenance   and  operational  cost.  Most
instrumentation operates on standard 110- to
120-volt power,  but there are times  when
voltage  regulators and transformers are used
to maintain  a constant  voltage or a  lower
voltage to certain circuits.
  To  prevent  damage to  the  structure and
equipment from smoke and overheating due
to  power failure,  an  emergency  standby
power system is  needed.  Alternate  safety
measures    include   automatic,
temperature-control  devices such  as a  water
cooling system, using city water or  stored
water, and emergency openings in the furnace
to bypass air pollution control equipment.
  Peak   power   demands  frequently   are
considerably   in   excess   of  average  power
consumption   and   may  require   special
provisions. The cranes and shredders  could
demand extra power and cause severe current
fluctuations that result in power shortage and
equipment  failures.  The  electrical  system
should  be  designed  to  accommodate the
power demand.
                                            16

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            Water Requirements

  The  quality  of  the  water required  for
incinerator  operation  will depend on its use.
Sources  may  include:  city  water,  on-  or
off-site wells,  rivers,  lakes,  and wastewater
treatment  plant  effluents. The total amount
of  water required  may vary  from 350  to
2,000  gal  per   ton   of waste  incinerated
depending on  design  and operation.1'2 Cost
for this portion  of  the utility service is from
$0.07  to  SO.40 per ton of waste incinerated,
based  on a water rate of $0.20 per 1,000 gal.
Incinerator  operation  requires a dependable
water  supply. An elevated water supply .serves
this purpose and can be used for fire fighting.
When  waste heat is  used to produce steam or
hot water,  the boiler feedwater and makeup
water  will  require  extensive  pretreatment.
Water  for air pollution control equipment, for
gas cooling, and  for dust control sprays need
not be  potable, but should  be free  from
suspended  materials.  Water  used  in   the
incineration   processes   will   increase   in
temperature,   change   in   chemical
characteristics,   and   will   acquire   solids.
Treatment  may   be  required before  these
waters are discharged.
  The  costs of   water recycling and  reuse
should be investigated. In reuse and recycling,
treatment  should be  effective in preventing
clogging,    erosion,    and    corrosion    of
equipment.
                   Sewers

  Preferably,   the   incinerator   should  be
located in  an area  served by sanitary sewers.
Untreated  waste  process  water should  be
disposed of through the sanitary sewer if the
system is capable of handling it. Storm sewers
should be used  only  for discharge of surface
waters.


              Communications

  External   telephone  communications  are
normally provided  by a trunk line  from the
switchboard    serving   the    municipality.
Communications within the  plant  are best
provided  by  an  intercom  system.  Public
address systems, bells, and other devices may
also  be effective. Soundproof  booths with a
visible signal system have been used in areas
with continuous high-noise levels.
  Extensive,   closed-circuit   television
monitoring  is  being  utilized  in  the power
generation  industry for supervision  and for
observing the combustion process. Although
attempts have been  made to  monitor large
incinerators, systems for this purpose are still
in the development stage.


                   Fuels

  Fuel may be  required for plant processes.
including building and water heating, and for
auxiliary fuel.  The choice of  fuel  for these
purposes will depend on availability and cost.
The  need is determined by  local conditions
and incinerator design.


              REFERENCES

1.  JENS. W., and F. R. REHM. Municipal incineration and
       air pollution control. In Proceedings: 1966 National
       Incinerator Conference, Ne\v York. May 1-4, 1966.
       American  Society  of Mechanical Engineers,  p
       74-83.
2.  MATUSKY, F. E., and  R. K. HAMPTON. Incinerator
       waste  water.  In   Proceedings;  1968  National
       Incinerator Conference, New York, May 5-S, 1968.
       American  Society  of Mechanical Engineers,  p.
       198-203.
                                             17

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                                      CHAPTER VI
                                     WEIGHING
  An incinerator scale weighs incoming solid
waste  and outgoing residue, including fly ash
and sittings. It  may  also  be  used to  weigh
salvaged materials.  Accurate and  meaningful
weight records  can   be  used  to  improve
operation, to assist management  control, to
facilitate   planning,   and  to  provide  an
equitable  means for assessing fees. Weights are
needed  for  cost  accounting,   rating  the
effective  capacity of the incinerator,  testing
air pollution control devices, and making a
materials balance for the facility.

  A  management  system  making  use  of
weights can serve to regulate and control solid
waste collection and disposal. Good collection
scheduling and routing may depend on such a
system.   Distribution   of  waste  deliveries
among available  plants requires prompt access
to weights of incoming material.  Cost control
to increase efficiency  and eliminate excessive
expenditures of time and effort  is dependent
on weight units.

  Observation  of  the  trends  in  quantity,
sources,  and types of solid waste collected
will  assist  in  planning for future disposal
needs.  Weight  records  of residue  assist  in
determining  the remaining  life  of  residue
disposal   sites,  and   thus  assist  effective
planning  as well  as  provide  a  means  of
calculating   combustion   efficiency.   If   a
community   wishes   to   charge    other
communities, private  haulers, or commercial
haulers for using the  incinerator,  the  weight
measurements   will   provide   a   practical,
equitable means for assessing fees.
              Scale Description

  Scale  Types.  A small incinerator (50 to
100 tons per day)  may satisfactorily use a
wood   platform,    manually    operated,
mechanical   scale   and  keep  handwritten
records.   At   the   other   extreme,   large
incinerators frequently  use automatic systems
employing load  cells,  electronic relay,  and
printed  output.  The electronic relay scales
allow for  greater flexibility  in  locating the
scale  platform in  relation to the scale house.
Highly   automated   electronic  scales   and
recorders are  more  costly than simple beam
scale; however, they  are  justified  in many
cases  because  they are  faster  and more
accurate.
  Size and Capacity.  The scale should have
sufficient capacity to weigh the largest vehicle
anticipated to use the incinerator on a routine
basis. The platform  should be  long enough to
accommodate  simultaneous  weighing  of all
axles. Separate  axle loading scales,  although
less expensive, are inherently  inaccurate and
slow in  operation. For  simultaneous weighing
of all axles, the majority of  collection trucks
could be  accommodated with a 10- by 34-ft
platform.1    A   50-ft    platform   will
accommodate most trailers  and semitrailers.
Scales should be  capable of weighing loaded
vehicles of up to 30 tons.
  Accuracy.  The  accuracy   and   internal
mechanism   of  the   scale   and   recording
mechanism   should  meet  the  commercial
requirements   for   the  State  or  other
jurisdictions  involved.   This  is  particularly
necessary if  user  fees  are based  on  weight.
                                            18

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Recommended scale requirements have been
outlined   by   the  National   Bureau   of
Standards.2
  Since municipal  records  are  seldom kept
closer than to the nearest tenth of a ton, and
since most applied  loads are within a range of
8 to 14 tons, scale accuracy of ±1.0 percent is
reasonable. All  scales should be periodically
checked and certified to 1  percent accuracy.
  Both   mechanical  and   electronic   scales
should be tested under load  during a quarterly
inspection.  This testing should  include:  (1)
checking for a change in indicated weight as a
heavy  load is moved from the  front to  the
back of the scale; (2) observing the action of
the dial during weighing or  for an irregularity
or "catch" in dial motion; and (3) testing the
scale with test weights.
  Platform.  The platform  or deck of a scale
may  be   constructed   of  wood, steel,  or
concrete.  Wood decks are least expensive, but
least durable. Many large truck scales have a
platform  constructed of reinforced concrete.
  Scale  Pit.  Scale-pit  walls   are   usually
concrete  and  should be  set in a  suitable
foundation to control  settlement.  A paved
scale-pit   floor   facilitates   cleaning  and
maintenance.  In all cases, scale-pit drainage is
essential.   Scale-pit depth should be sufficient
to allow periodic inspection and maintenance
of  the  scales.   Access to  the pit should  be
through the wall or through  a  hatch  on the
platform.   Gutters around the  edge  of the.
scale pit  to intercept runoff from the deck
have been used  effectively to  ensure a dry,
clean scale pit.   Lighting should be  provided
to aid  in inspecting and  maintaining the scale
mechanism and in cleaning the scale pit.
     Operation and Maintenance of Scales

  Operation.  The  number of  vehicles that
can  be  weighed per unit time will vary with
the weighmaster, automation, and amount of
data to be collected. Under some conditions,
an  experienced  weighmaster may be able  to
manually  record,  for  short periods of time,
the net weight and type of material at a rate
of 60 trucks per hr. This rate may decrease to
as few  as  10  to  20 trucks per hr, however,
under other conditions.  A highly automated
weighing procedure can easily maintain a rate
of over 60 trucks per hr,  record more data,
require less supervision, and be more accurate.
Incinerators with  a capacity of 1,000 tons or
more per day will usually require two or more
scales.

  Tare   Procedures.  Net  weights  of waste
loads require subtracting vehicle tare weights
from the gross weights of the loaded vehicles.
This process  can  be performed in several
ways. (1) In the case of a small incinerator
with relatively few incoming loads each day,
the  vehicle  can  be weighed when full and
when empty. (2)  At other plants, particularly
where  access  to  the scale prevents double
weighing, it would be simpler to make a list of
the vehicles regularly delivering waste to the
facility  along  with their tare weights. After
each transaction  or at the end of the day or
week, the tares can be subtracted to provide
net  weights.  In  this  system,  it would  be
necessary  to weigh  up  and  record the  tare
weights of the vehicles only for the purpose
of  an   accurate  list.  (3)  Some  automated
electronic scale systems include devices  for
automatically   subtracting  the  tares  and
providing written records of net load weights.
In such systems, each vehicle must  have been
weighed up empty to provide  a tare value,
which is then  recorded on a credit card or a
tare  key carried by  the  vehicle operator and
inserted in  the scale mechanism at the time of
the scale transaction. (4) The most accurate
and  most  secure system of  obtaining  net
weights is through a two-scale system at each
plant with fully-controlled access.  One scale
would weigh in the loaded vehicles; the other
would weigh out the empty vehicles.
  Except when vehicles  are weighed twice,
recorded   tare   weights  are   subject   to
adjustment due to several factors. Equipment
may be added or  removed from a truck. Such
                                           19

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 a change in  tare weights can only be detected
 by  periodically  reweighing the empty truck.
   Fuel errors can be reduced by checking the
 tare weights when  fuel tanks are half full.
 Errors resulting  from the weight of collection
 personnel can  be avoided by  using  a fixed
 procedure whereby  personnel are always on
 or off the scale during weighing operation.
   Maintenance.   Unless misused, motor-truck
 platform  scales   require little  maintenance.
 Periodic  inspections will ensure the  proper
 functioning  of the scale. To protect the scale
 from rust, the pit should be kept dry and the
 metal  parts of the   structure  should  be
 undercoated. If competent employees are not
 available  for scale  maintenance, a contract
 repair  and maintenance program  should be
 considered.
   Good housekeeping  in the pit will reduce
 maintenance  and repairs  of the levers in a
 mechanical  scale.  The knife  edges  at the
 pivots of a mechanical scale should be  cleaned
 and greased  at least annually. The pivots and
 levers  should be inspected  at least every 3
 months to ensure freedom  from obstruction,
 wedging,  and jamming, and alignment  of
 levers  and  position  of pivots;  nose  irons
 should be checked during the inspection. The
 gap  around  the  scale  platform should  be
 checked   daily    for   obstruction.   An
 all-electronic  scale requires less maintenance
 in the pit, but more electronic maintenance
 aboveground.
  Problems.  Although   a  seemingly  simple
 operation, many  problems are encountered in
 weighing.  The first  is  bypassing  the scale.
 Loaded trucks may  bypass  the  scale during
 the confusion of peak  unloading periods and
during unattended periods. To prevent this,
elaborate  controls and  accounting techniques
 have been developed.  A two-gate system (one
 at  the front end  and one at the back of the
 scale) for locking a  truck on the scale  until
 weighed,  signal   lights,  curbing,  alarms,
 automated recording devices,  one-way exit
 barricades, weighmaster keys  or  cards tor
 fixing responsibility of transaction, multicopy
 weight tickets, and simultaneous transmission
 of   weighing   information   to   a  central
 computer are all being used to ensure accurate
 weighing of every  incoming load.
  Misplacement of the truck  on the platform
 can  cause  errors when an axle is off or only
 partially resting on the scale.  Suitable curbing,
 markings, elevated transverse  bumps, or extra
 long   scales   can   reduce   or    prevent
 unintentional  misplacement of the vehicles on
 the scale.
  Dirt, water, snow, and ice may accumulate
on and under the  deck and cause wearing and
rusting   of  the  scale,  hazardous  driving
conditions,   and   errors  in  the  payload.
Cleaning the  truck platform and  removing
accumulated material will help alleviate  these
problems. The top surface of the deck may be
crowned or pitched  1/16 to  1/8 in. per  ft
transversely  to improve  runoff.  Imbedded
heating   elements  may  be used  to prevent
buildup of ice and snow.
              REFERENCES

1.  ROGUS, C. A. Weigh refuse  electronically. American
       City, 72(4):128-130, 165,  167, 169, 171. Apr.
       1957.
2.  U.S.  NATIONAL BUREAU OF STANDARDS.
       Specifications, tolerances,  and other technical
       requirements for  commercial weighing  and
       measuring devices adopted by National Conference
       on Weights  and Measures. Handbook 44. 3d ed.
       Washington, U.S. Government Printing Office, 1965.
       178pp.
                                            20

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                                      CHAPTER VII
              RECEIVING AND  HANDLING SOLID  WASTE
  Solid waste is  delivered, usually during the
day shifts, in several types and sizes of trucks
and vehicles. The  vehicles are  first weighed
and then proceed to the tipping area. At large
installations, the trucks unload into a storage
pit, whereas at small incinerators, the practice
has been to  dump  the waste directly into the
furnace  charging hopper or  onto the tipping
floor.
  After the waste have been unloaded into the
storage pit,  the material must be transferred
to  the charging hopper.  For incinerators with
charging  hoppers  located above  the  storage
pit, the  transfer  is usually performed  by
overhead cranes. Some incinerators have the
charging floor on the same level as the storage
area, and transferring is usually  done  with a
front-end loader or special equipment.
  The solid waste is  charged into the furnace
by   dropping it  directly  through  a  gravity
chute  or pushing  it into the furnace with a
ram.   After  deposition,   the   waste   is
mechanically moved through the furnace.


               Tipping Area

  The  tipping area  is the flat area adjacent to
the  storage  pit  or charging hoppers  where
trucks maneuver into position  for dumping
(Figure 4), The area should be large enough to
allow  for safe   and easy maneuvering and
dumping.
  Dimensions.  Collection   trucks  tend   to
arrive  at the  incinerator in large numbers
during a short  time interval.   To  avoid  a
backup of trucks,  the  length of the tipping
area and  storage  pit  should receive  careful
design  consideration. The  total length of the
tipping area should  extend the length of the
storage pit and, if possible, beyond the pit.
Width  of individual dumping spaces along the
pit should be about  10 to  12 ft. These spaces
should  be  clearly  marked. Support columns
should  be  placed to  avoid interfering  with
dumping spaces.
  The  tipping area width  should be  greater
than the  turning  radii  of trucks using the
tipping area.  For  single  chassis  compactor
                             CRANE
                            OVERRIDE
                             AREA
        TIPPING
         AREA
          AT
      GROUND LEVEL
               BUMPER-'"1-''
                 STOP
       TIPPING AREA WIDTH
                         STORAGE
                          PIT
                             CRANE
                             BRIDGE
                             RAILS
                                     LOADING
                                     ^SHAFT
                                      CHARGING
                                     v- HOPPER
                                      CHARGING
                                       FLOOR
   Figure 4.  Plan of tipping area and storage pits with
crane.
                                             21

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 trucks, the radius is between 25 and 35 ft; for
 tractor trailers, the radius is between 35 and
 50 ft. The minimum recommended width of
 the tipping area is 50 to 70 ft; if the space is
 available, the width should be larger.
   The  entrance,   exit,  and  ceiling  of  an
 enclosed  tipping area must be high enough to
 provide  the  necessary  clearance  for  dump
 trucks. Ceiling height is critical at the edge of
 the tipping area when the packer and dump
 bodies are raised in the unloading position. A
 minimum  of  24  ft is recommended,  but
 greater vertical clearance may be necessary for
 some trucks.
   Vehicle entrances and exits should provide a
 minimum of 18 ft of vertical clearance. Exits
 should be provided with warning devices, such
 as hanging chains, to prevent careless drivers
 from attempting  to exit  with  raised  dump
 bodies. The  entrance  and exits should  be
 equipped  with wheel guards  to  protect  the
 door jambs.
   Tipping  Floor  Enclosure.  Enclosing  the
 tipping area  should be considered. Climatic
 conditions may make it desirable. In addition,
 an  enclosed  tipping   area   is   definitely
 recommended for  good  public relations. Dust
 control,   odor   confinement,   and   noise
 reduction  effected  by  enclosure  will  help
 make the incinerator more acceptable to the
 community.
  Other Aspects of Tipping Area Design.  The
 floor  of   the   tipping   area   should   be
 constructed  to withstand the  heavy  loads
 placed on it; it should slope away from  the
 storage pit toward a drain so that the area can
 be  regularly cleaned and flushed.  The floors
 are usually rough surfaced for traction.
  Because of the  debris  that accumulates in
 the  tipping  area,  the   drainage  system  is
 required to accommodate large quantities of
 wash water. The size of the receiving sewer is
 critical if the discharge  is to such a  system.
Bar grates  or other suitable  devices can  be
used  to  prevent  large  objects  from  being
discharged   to  the  sewer   and  possibly
 obstructing flow.
  Scattered dust and litter from the dumping,
 recasting,   and   charging  operations   are
 problems  common  to solid waste  handling.
 Provisions for cleaning the tipping area should
 be   considered  during  the  design   phase.
 Vacuum  cleaning facilities,  a compressed air
 system   for   cleaning  electrical   contacts,
 powered  mobile sweepers,  and flushers have
 been successful in controlling  the  spread of
 dust and litter.
  Because of dangers involved in the handling
 and  dumping of large trucks in close quarters,
 safety in  the  tipping  area should be stressed
 by   the   incinerator   supervisor.  Hold-down
 chains  or  bumper   picks   are  sometimes
 employed to prevent trucks from being tipped
 into the  pit; however, use  of these safeguards
 is time consuming,  and short ramps  sloping
 away from the storage pit at an angle of 8° to
 12°  from the horizontal will prevent mishaps
 efficiently.
  Most plants are constructed with  a curb or
 backing bumper along the entire length of the
 pit  to prevent trucks from  backing into the
 pit.  This  barrier must  be  high  enough  to
 prevent   trucks  from overriding,  yet low
 enough to permit the chassis  overhang to clear
 the curb.  A height of about  1 ft is considered
 adequate. The  face of the backing bumper is
 usually vertical or slightly concave to conform
 to the shape of the wheel. The barrier must be
 durable enough to withstand repeated impact
 and  must be  securely anchored  to prevent
 movement. It  should  contain openings so that
 spilled waste can  be  shoveled or swept from
 the tipping floor into  the pit.
  Other  measures to  be  considered for the
 safe   operation  of a  tipping  area  are:  (1)
 designing  tipping area, storage pit, and crane
 to  eliminate   possibility  of crane bucket
 striking extended dump  body; (2) using a
 traffic director  at  larger  incinerators;  (3)
 permitting the  dump  bodies of packer trucks
 to be  raised only when the truck  is  in  the
unloading space.
                                           22

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                Storage Pit

  The purpose  of the storage pit is to provide
a safe  and convenient holding place for solid
waste before it is charged to the incinerator.
In a properly designed storage pit, waste from
numerous sources can be mixed to provide a
more uniform feed for the furnaces.
  Capacity of the Storage Pit.  When the rate
of receipt of solid waste  exceeds the burning
rate,  material  must  be  stored  for future
processing.  The  total  space   for  storage
depends  upon  the  amount  of   material
remaining after the daily  receiving period and
the amount that is left unburned from day to
day  during times of peak waste  delivery. The
storage  pit is  usually designed  to  contain
about   1.5 times  the 24-hr capacity of the
incinerator. If heat recovery is practiced, the
pit  storage capacity  should  receive  special
study   to  ensure  a  supply of solid  waste
adequate to  meet  the heat demand  when
waste is not delivered to the incinerator.
  To calculate the  necessary storage  volume,
the unit weight of solid  waste in the storage
pit must be known. The generally  accepted
average unit weight of waste in a storage pit is
about 350 Ib per cu yd.
  When designing storage  pits, future changes
in waste density  should  be  considered. As
noted,  in recent years, solid waste density has
been decreasing.
  Other Aspects of Storage Pits.  Storage pits
are usually  rectangularly  shaped  because  of
crane  design  and  ease  of construction.  A
rectangular pit allows the crane supports to be
constructed with the use of the existing pit
walls and bracing. Some pits are divided into
separate  rectangular  units  with  charging
hoppers between units. With this design, a fire
that may start in a pit can be isolated, and pit
cleaning is facilitated because of the ability to
alternately empty the pits.
  The width of a storage pit usually does not
exceed  30 ft. Minimum width is usually 15 to
20 ft or wide enough to allow a monorail
crane to operate without  being obstructed by
the  overhang  of  trucks  in  the  dumping
position.
  The  walls  of the pit  must withstand  the
external  forces caused by water and soil and
the internal pressures of solid waste and water
in the pit, a condition that could occur during
pit fires. During crane operations, the crane
bucket  may  collide with the wall  and crush
the  concrete.  Continuous  steel  plating  or
embedded steel T-sections in  the concrete can
protect areas of the pit subject  to repeated
impact.
  Fires occasionally develop  in the pit. They
can be caused  by sparks carried  over  by  the
crane during  the charging operation, from live
coals  in  the  collected waste, or spontaneous
combustion of stored waste.  Smoke and heat
can damage  the  crane,  break windows, and
ruin equipment.  Crane  damage can put  the
entire  plant  out of operation for weeks  or
longer. The pit area should be equipped with
an adequate number of fire hoses of effective
size.  The   dewatering   facilities   must   be
adequate for  the expected quantities of water
used in fire fighting. Portable pumps help to
remove excess amounts of water.
  The  entire pit should be  watertight and
sloped to troughs and drains for dewatering.
When a pit is constructed below grade, it will
usually   be  necessary   to   have  a  sump.
Screening devices to prevent material from
entering the sump are also recommended.
  The  sources  of  water and  the  resulting
quantities vary  with the installation.   When
pits are not watertight, leakage can occur as a
result of the positive hydrostatic pressure of
groundwater. Waste collected in wet weather
may be  saturated,  and  vertical drainage will
occur  in the pit.  Water from dust control
sprays also enters the pit.
  Cleanout facilities are  needed to empty  the
pit if the furnace equipment breaks down or
to  remove   unwanted   items  inadvertently
unloaded into  the  pit and remove saturated
waste after a fire.  A loading shaft from  the
charging  floor to the ground level is useful for
unloading  the  pit   and  for  hoisting   heavy
                                            23

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 equipment and material from ground level  to
 the charging door (Figure 4).

              Charging Methods

   Solid  waste  is charged into  the  furnace by
 several methods. In small installations where
 the storage area is  on the same elevation  as
 the  charging  hoppers, a  front-end loader,
 vibrating  hopper  and  conveyor,  or  other
 mechanical  means   are   used.   At   larger
 incinerators, cranes charge the solid waste.
   Besides   transporting  solid  waste  to the
 charging  hoppers,   cranes  also  mix  and
 distribute   the  solid waste in  the pit.  This
 action  results  in  a  more uniform  burning
 material and better utilization of pit capacity.
   Crane Types.  The  types most  commonly
 used are the monorail  crane and  the bridge
 crane (Figure  5). The  former  is a fixed unit
 suspended  from a  single rail that  crosses the
 pit  in  only  one  horizontal  direction.  The
 bridge crane differs from the monorail in that
 it can maneuver horizontally in two directions
 rather than one. The capacity of the monorail
 crane is usually less  than that of  a  bridge
 crane; the width of the storage pit is restricted
 to include  only that lateral area within  reach
 of the open bucket. Capital cost of a monorail
 crane is less than that of a bridge crane, and  at
 some  incinerators,  its performance  may be
 adequate.
  Crane  Capacity and Bucket  Design.  The
 size of crane needed to operate an incinerator
 is a  function  of incinerator  capacity.  Each
 continuous-feed-type furnace requires a given
 number  of bucket loads at regular intervals.
 The  size  of  the  bucket,  therefore,  is  a
 function of the  24-hr furnace  capacity and
 number  of  bucket  loads per 24 hr. Once the
 size  of  bucket  has been fixed,  the crane
 capacity can  be specified. For example,  a
 4.5-ton crane is recommended  for  use with a
 2.5-cu-yd bucket.
  The  number  of bucket  loads  that can be
charged during a given period  depends  upon
the number of cycles that the crane can make
                    SECTION
  Figure 5.  Plan view and section view of bridge crane.


during  the charging  operation.  A  cycle  is
defined as the time for loading and lifting the
bucket, trolleying and bridging to the charging
hopper, dumping, and returning  for another
bucket load. Typical cycles vary  from  1-1/2
to 3  min. To determine the cycle  time, the
hoisting, bridging, and trolleying speeds must
be known, as well as  the length, width, and
depth of  storage pit.  Typical  hoisting and
trolley speeds are between 250 and 300 ft per
min,  whereas bridge travel  speeds may  be as
high  as  350  ft per min. In general, design
criteria does not require high speeds.
  Incinerator  cranes usually use  the closed
scoop bucket or a grapple. The closed scoop is
a  clamshell  with  heavy  steel  lips usually
equipped   with  short   teeth   to  increase
penetrating ability. The grapple type is similar
to a  clamshell  but  has much longer teeth,
called  tines.  This type has a  considerably
larger  capacity than an  equally  rated closed
scooped bucket. The grapple is a poor cleanup
tool  because  of  the length and  spacing  of its
                                           24

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tines. For cleaning purposes, the grappple can
be equipped with bolted-on pans.
  Number  of Cranes.  Crane  downtime will
stop incinerator  operations unless a standby
crane is provided. Nearly all installations with
a capacity above 400 tons per day (TPD) have
a  second  crane  to  prevent  shutdowns.  A
second crane is recommended for plants with
over a  300-TPD capacity.  Because of high
costs, most small plants have only one crane.
At  larger installations, a third  crane is often
justified, and nearly 50 percent of the plants
with  over  a 850-TPD capacity have  'three
cranes. With  a second or third crane, space in
addition to the operating space required  for
the  first crane  must be provided for the
storage  of  the units when not in service. The
point of storage for the nonoperating units
must not interfere with the operating unit.
  Control and Operation.  The crane can be
operated manually  from a cab traveling with
the crane  or form  a remote fixed  operating
point.  Manual  operation  form a mobile cab
has  some  advantage  over a  remote  fixed
operating  point.  The  operator has  better
visibility, which usually yields better and safer
operation.  Where the pit is long, the distance
judgment error  is reduced  with mobile cab
operation.
  When  a  mobile cab is  used,  the operator
should   have a  safe  convenient  boarding
platform. Since the charging  operation may
be  dusty and hot, the crane cab should be
air-conditioned.
             Charging Hoppers

  Charging hoppers are used  to  maintain  a
supply  of solid waste  to  the  furnace.  In
batch-feed furnaces,  a  gate  separates  the
charging  hopper  from   the  furnace  and
supports the solid  waste while the furnace is
burning  the  previous  charge.  Generally one
hopper is provided for each furnace cell. In a
continuous-feed   furnace,   the  waste-filled
hopper and chute assist in  maintaining an air
seal  to the furnace  as  well  as  to provide a
continuous supply of solid waste.
  Most charging hoppers have the shape of an
inverted, truncated  pyramid. The size of the
hopper opening  depends somewhat upon the
size  of the furnace,  but  it  should  be large
enough   to  prevent  arching  of  oversized
material across the hopper bottom. Common
hopper openings measure from 4 X 4 ft to 4
X 8  ft. The hopper should be deep enough to
receive a  bucketful of solid waste without
spilling over.
  The charging hopper is  generally  steel and
sometimes  concrete lined. Because of abrasion
from solid waste,  impact from  the  crane
bucket,  and  heat  from  the  furnace,  the
hopper   must  be   constructed  of  rugged
material  and  built  to  facilitate repair and
replacement

              Charging Chutes

  The charging chute connects  the hopper to
the furnace and  may be nearly  as wide as the
furnace so that the  solid  waste  will  pass
through  the  chute  without clogging.  The
discharge of waste into  the furnace is usually
by gravity, but reciprocating or vibrating feed
mechanisms  may  also  be  used.  Several
measures  may  be  taken  to  prevent  solid
waste's tendency to clog chutes. These are use
of: smooth inside surfaces; corrosion resistant
materials; vertical  (or nearly vertical) chutes
with increasing cross section.
  The   charging  chute,  because   of   its
proximity  to the furnace, should be protected
against extreme  heat. For this reason,  chute
walls are  often  water jacketed.  A hopper
cover or other  means  of  closure should  be
provided   for  ending  a   burning  cycle  in
continuous-feed furnaces.
                                            25

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                                     CHAPTER VIII
                     FURNACES  AND APPURTENANCES
   Incineration  is  a  controlled  combustion
 process for burning solid, liquid, or  gaseous
 combustible waste to gases and to a residue
 containing little or no combustible material.
 When  solid waste is  exposed to a turbulent
 atmosphere  for  a  critical time  period at
 an elevated temperature, combustion occurs.
 During  combustion,  moisture is evaporated,
 and the combustible portion of the solid waste
 is vaporized and then oxidized.   Concurrent
 reactions are the oxidation of metals and the
 oxidation  of  such  elements  as sulfur  and
 nitrogen.  Carbon dioxide, water vapor,  ash,
 and  noncombustibles  are  the  major  end
 products of combustion.
  The combustion processes take place in the
 furnace of the incinerator, which includes the
 grates  and combustion  chambers. There are
 numerous   designs   or   configurations   of
 furnaces to accomplish  combustion, and, to
 date, no one  design  can  be considered  the
 best.

                 Furnaces

  Furnaces    commonly   used   for   the
 incineration of municipal  solid waste  are the
 vertical   circular   furnace,   the   multicell
 rectangular furnace, the rectangular furnace,
 and  the rotary kiln furnace.1  Although these
 furnaces vary  in  configuration,   total space
 required for each is based  on a heat  release
 rate  of  about  18,000 Btu per cu  ft of furnace
volume  per hr, although  heat  release rates
varying from 12,500 to 25,000 Btu per cu ft
per hr have been used.
 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 6). 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
required. 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.
  The multicell rectangular type, also called
the   mutual  assistance  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
7).  Solid  waste is usually charged  through a
door  in the top of each  cell. Generally, the
cells of the furnace have a common secondary
combustion  chamber  and  share  a residue
disposal hopper.
  The  rectangular   furnace  is   the  most
common   form   in   recently   constructed
municipal  incinerators  (Figure  8).  Several
grate  systems  are  adaptable  to  this  form.
Commonly,  two or more  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
                                           26

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                                         - CHARGING HOPPER
                                Figure 6.  Vertical circular furnace.
  A  rotary kiln furnace consists of a  slowly
revolving   inclined   kiln  that  follows  a
rectangular furnace where  drying and  partial
burning  occurs  (Figure  9). The  partially
burned waste 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 particulates occurs in the mixing
chamber  beyond the  kiln  discharge.  The
residue falls from the end of the kiln into a
quenching trough.
  Grates and Stoking.  The grate system must
transport the solid waste and residue through
the furnace and,  at the same time,  promote
combustion by  adequate agitation 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  agitation
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.2  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 openings.
Mechanical grate systems must withstand high
temperatures,    thermal   shock,  abrasion,
wedging, clogging,  and  heavy loads.  Such
severe  operating conditions can result  in
misalignment of moving parts,  bearing wear,
and warping or cracking of castings.
                                          27

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            CHARGING CHUTE
     TO
 SECONDARY
 COMBUSTION
  CHAMBER
                                                                                    OVERFIRE
                                                                                    AIR  INLET
                                                                                    STOKING
                                                                                      DOOR
                                                                           RESIDUE
                                                                           HOPPER
                           Figure 7.   Multicell rectangular furnace
  For design purposes, the required grate area
is  approximated by  dividing  Ib per hr solid
waste to be burned by the  Ib  per sq ft per hr
solid waste  the grates are capable of burning.
Ordinarily,  the  design value  for  the  grate
loading will be between 50  and 70 Ib per sq ft
per hr.  This design value depends mostly on
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 sq  ft per hr. An average rating of 300,000
Btu per  sq  ft grate per hr 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,
reciprocating,  rocking, rotary  kiln, circular,
vibrating, oscillating, and reverse reciprocating
grates; multiple rotating drums; routing cones
with arms; and variations or combinations of
these types.  In the  United  ::'ate.;, traveling,
reciprocating, rocking rotary  kiln,  nad-cu  <-
grates are the most widely used.
  Traveling  grates  are continuous,  belt-j;J-p
                                            28

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                 CHARGING
                  CHUTE
to
                                                               SUPERSTRUCTURE	v
                                                            CURTAIN
                                                              WALL
                                CURTAIN
                                 WALL
GAS  FLUE TO
 EXPANSION
                                                        COMBUSTION CHAMBER
                                                                                           FURNACE
                                                                                            ACCESS
                                                                                             DOOR
                                                                       ASH  AND CLINKER
                                                                             DISCHARGE
                                                       HORIZONTAL
                                                     BURNING GRATE
                                                 Figure 8. Rectangular furnace.

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                                                             TO EXPANSION CHAMBER

                                                            AND GAS SCRUBBER
                                                    RESIDUE CONVEYORS
                                  Figure 9.  Rotary kiln lurnace.
conveyors  (Figure 10). A single traveling grate
does  not  promote  agitation. Two  or more
grates  at  different  elevations  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  11). 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.
  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  12).
Rocking  grates have  also been 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  in  a  slowly cascading and forward
motion.
                                   Figure 10.  Traveling grates.
                                            30

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                                                     GRATES
                  MOVING
                  SRATES
Figure 11.  Reciprocating grates.
                                      RAISED POSITION
                                 NORMAL POSITION
  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 13).
  Charging   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
intermittently  through  a  charging gate  or
hatch, which is closed except when waste is
being charged. The  waste may be stored in a
hopper  and   fed intermittently 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
                                                                       Figure 12.  Rocking grates.
to feed a batch of material directly to the gate
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   nonuniform   rate   of  feeding   and
intermittent introduction of large  quantities
of cool air.
  Siftings  Removal.  Siftings  are   the   fine
materials that fall from  the fuel  bed through
the grate openings during the drying, ignition,
and burning processes. Siftings consist of ash,
small fragments of metal, glass and  ceramics,
and  unburned  or  partially burned  organic
substances.  In   some  designs,  siftings are
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.
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  A Rotating Cone
  B Extended Stoking
    Arm (Rabble Arm)
  C Stationary Circular
    Grate
  D Peripheral Dumping
    Grate
            Figure 13.  Circular grates.


 Sittings  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.
  Residue    Removal.  Residue-all   solid
 materials remaining  after  burning—includes
 ash,  clinkers,   tin  cans,  glass,  rock,   and
 un burned    organic    substances.    Residue
 removal  can either be 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 (Chapter XII). 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. Discharge may be placed into
 trucks or other containers  for transport to a
 disposal  area. Access  to the residue hoppers is
 usually by a tunnel beneath the furnace floor.
 Ash tunnels should be wide enough to  allow
 an employee to safely walk past a vehicle. The
 tunnel should be paved, well drained, and well
 lighted.   Provisions  should  be   made   for
 adequate ventilation and dust removal. Excess
 quench water should  be drained before trucks
 are  loaded,  and  the   residue   trucks   or
 containers  should  be  watertight.  Residue
 trucks dripping quench water to the disposal
 site  are unsightly, insanitary, 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 heavy
 loads  and  continuous 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.  For continuous,
 dependable operation, a dual conveyor system
 is justified in plants above 250-TPD capacity.

                Combustion

  Time,   temperature,  and   turbulence  are
 commonly called the three T's of combustion.
When solid  waste is exposed  for a sufficient
 time  to   a  turbulent, hot  atmosphere,  the
waste will be satisfactorily incinerated.
  For a substance  to  burn,  both surface and
internal  moisture  must be  driven  from  the
                                           32

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material.   The   vaporization   of  moisture
present  in  waste  material  will  keep  the
temperature  of  the  material  below 212 F
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.   This  drying  process
continues throughout the entire length of the
furnace, but proceeds  at  the greatest  rate
immediately  following charging of the solid
waste.
  To facilitate drying, some  furnace designs
use  preheated air or incorporate 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.
  The combustion process in incineration is
thought of as occurring in two  overlapping
stages,  primary  combustion  and  secondary
combustion.  Primary combustion  generally
refers   to   the   physical-chemical  changes
occurring in proximity  to the fuel  bed  and
consists of drying, volatilization, and ignition
of  the solid waste.  Secondary  combustion
refers   to   the   oxidation   of  gases   and
particulate   matter  released  by   primary
combustion.  Secondary  combustion  achieves
combustion   of   unburned   furnace  gases,
elimination  of   odors,  and  combustion  of
carbon  suspended in  the gases. To promote
secondary  combustion,  a  sufficiently  high
temperature  must  be maintained, sufficient
air  must  be supplied,  and  turbulence  or
mixing should be imparted to  the gas stream.
  The  function  of turbulence  is  to  ensure
mixing of each volume of gas with sufficient
air   for   complete   burning  of  volatile
combustible    matter   and   suspended
particulates. The  turbulence must be intense
and must persist long enough for mixing to be
completed  while  the  temperature is still high
enough to ensure  complete burning.
  Introduction of Air to the Furnaces.  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   stoichiometric   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,   the  best  proportions  are
determined by  trial  and error.  For  most
municipal incinerator designs, underfire air is
from 40 to 60 percent of the total  air. (Total
air is the  total of all underfire, overfire, and
infiltration air.) This amount of underfire air
air provides acceptable combustion in the fuel
bed and adequate grate cooling. In general, as
the underfire air is decreased, the burning rate
is inhibited.
  To  supply   adequate  air  for  complete
combustion and  to promote  turbulence, 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  tube  wall  furnaces require only 50 to
100 percent excess air.
  Gas  Flow from Furnace.   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.  Gas  velocities  must  be
                                           33

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 determined  so  that gas passages can be sized
 to  prevent excessive settlement of entrained
 particles.
   Incinerator stacks provide natural draft and
 dispersion  for  gases and  participate matter.
 Accordingly, the height and diameter  of the
 stack  depend  upon  the  amount  of  draft
 required and  the topographic and  climatic
 conditions.  If necessary,  induced  draft fans
 should  be  used  to  supplement the natural
 draft in moving gases through the incinerator.
 The decision to use  a  tall stack with natural
 draft only, a short stack that relies principally
 upon induced draft, or a combination of these
 should be made by the designer after careful
 consideration of ambient air quality, health
 effects,  Federal Aviation Agency regulations,
 architecture, and other constraints.
   To  adequately  control  the  combustion
 process, the  draft must  be regulated. Dampers
 are  generally used in both natural draft  stacks
 and in stacks employing induced draft fans of
 constant  speed.  Adjustable  speed,  induced
 draft  fans  are  also  used  to  control  draft.
 Under most  conditions, an induced draft fan
 is preferred over natural draft stack. Control
 over the  burning solid waste  can  be better
 maintained   and   air  pollution   collection
 devices better operated with the constant air
 volume and  uniform pressure drop that the
 induced draft fan creates.


    Combustion Temperature and Cooling

  Adequate    temperature,   time,   and
 turbulence are  necessary to  completely burn
 the  gases  and carbon suspended in  the gases
 and  to destroy  the odors. If temperatures are
 too   low,  the   oxidation  reactions   are
incomplete; if too high, the temperatures can
cause  equipment  and   structural   damage
throughout the  incinerator.  Excessively high
temperatures can cause refractories to fail
through excessive expansion, can cause slag
buildup  on  the  furnace  linings,   or   may
produce  oxides  of nitrogen. When  the air
 stream  is  suddenly cooled,  these  nitrogen
 oxides do  not have time  to decompose  to
 nitrogen and oxygen. Because of variations in
 composition and  density of  the solid  waste,
 careful  operation  is  required  to maintain
 furnace temperatures  within  the desirable
 range.
  Temperature.  At the air intake, combustion
 air is at ambient temperature. Combustion air
 may  be preheated to 200 to 300 F. Once  in
 the furnace,  the  temperature  rapidly  rises.
 Immediately above the burning waste, the
 temperature of the burning gases generally
 ranges from 2,100 to 2,500 F, and for short
 periods  of  time,  it may  reach 2,800 F in
 localized  areas.  When  the  gas leaves the
 combustion chamber, the temperature should
 be  between  1,400 and  1,800 F. The gas
 temperature  entering  the   stack   can  be
 expected to be 1,000 F  or less. Where induced
 draft  fans,  electrostatic  precipitators,  and
 other devices requiring lower gas temperatures
 are used,  the  gases will  have  to  be cooled
 further.  Before  they enter the air pollution
 control devices,  the gases  should be cooled to
 500 to 700 F 3
  In  a  batch feed  incinerator,  opening the
 charging door lowers the temperature of gases
 in  the  combustion  chamber  by as much as
 500 F. Introducing extremely high or low Btu
 wastes  can  also cause  abrupt  and extreme
 temperature change.
  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  incinerator  designs   are  based  on
 temperatures within  the  1,400  to  1,800 F
range. In  practice,  operating  temperatures
frequently fluctuate by  200 F or more from
this design range sometimes in a matter of
minutes. The furnace temperature should be
                                           34

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maintained   at   fairly   constant   levels,
preferably  in  midrange.  Such operation will
accommodate   sudden  temperature changes
within the 1,400 to 1,800 F range. In some
cases,  auxiliary  fuel   will  be  needed   to
maintain satisfactory temperature.

  Methods of Cooling the Furnaces and Flue
Gas.  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
available, some excess air  is  still used but
primarily  for   ensuring   turbulence  and
complete combustion.
  In all incinerators, some heat is lost through
the  furnace  walls.  The  amount  of heat
dissipated  in  this manner is small compared
with  the total  heat  release;  however, these
heat losses must be considered when designing
the furnace.
  The purpose of excess air is to cool and mix
the  hot  gases  through a  dilution process,
which lowers  gas temperatures. The  cooler
ambient air is mixed with the hot combustion
gases,  and an  equilibrium  temperature  is
reached.
  Water injected into the hot gas stream cools
the flue gas through evaporation of the water
and absorption 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.  Water
cooling  is  used  on  flue  gases  but  is not
generally employed in cooling the furnace.
  Although heat exchange through the use  of
water  tube  walls  and boilers  is not   in
widespread use  in the United  States, it  is
attracting greater attention  and is  employed
in  Europe.  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.  Because  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.
                Refractories

  Refractories,  materials  employed to resist
heat,  are  commonly used in incinerators to
line   furnaces,   subsidence   chambers,
breechings, and stacks. Most refractories are
composed  wholly  or  in part  of alumina,
magnesia, and  silica although  chromite  and
zircon  are common  synthetic  or artificial
refractories.  Many  of these  materials  are
interground with kaolin,  the  oldest and most
widely used natural refractory.
  Refractories  are classified according to their
physical  and chemical  properties which vary
considerably.4   Their   thermal   expansion
characteristics,  heat conductivity,  hardness,
strength, and chemical resistivity also vary.
  Refractories  are   commonly  precast  as
bricks, which  are laid with mortar. They can
also be used in the form of dry powder, which
is mixed like cement with water and cast in
forms.  Plastic refractories are  pre-mixed  by
the manufacturer with just enough water to
be  plastic or moldable on the job; they are
used mainly  as a patching  material  and in
confined  area,  but  have   been  used  for
complete furnace linings.
  The   mortars  used  to  lay  and  bond
refractory  brick are  either  air  setting  or
thermal  setting.  Air-setting  mortars  harden
more   or  less  uniformly   at   outside   air
temperature   through   normal   hydration
processes,   whereas   thermal-set   mortars
depends on the degree of heat penetration.
  Refractories  expand  in all  directions when
heated;  therefore, expansion joints must be
provided. Failure to do so can cause a buildup
of stresses that could produce cracks and in
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  some cases even structural failure.
    Furnace Walls.  In the past,  furnace walls
  were designed to conserve as much heat as
  possible from  the  combustion process. With
  today's higher heat value waste, the previous
  emphasis on conserving heat  throughout  the
  furnace has decreased.  In  the last  15 yr,  the
  trend   has  been   toward   thinner  (9-in.)
  refractory  walls  and  away  from  massive
  fire-brick refractories.  Indeed the emphasis
  now is on withstanding temperatures in excess
  of 2,000  F  and  on  preventing  refractory
  softening,  erosion,  slagging,  and spalling.  In
  areas such as  the  drying and ignition  zone,
  however,  where a high temperature is desired,
  the heat storage capacity of the walls and heat
  reflection continues to be important.
   Furnace  walls  constructed  with  refractory
  linings are the  most common and probably
  will  continue to remain popular. The thinner
  walls of  modern  design  are supported  at
  frequent intervals by anchors attached to a
  steel superstructure that bears the majority of
  the  refractory   weight.   They are  therefore
  suspended  walls rather  than  of  conventional
  bearing  or arch construction. The large flat
  roofs  of  most rectangular  furnaces   are
  constructed in  a similar manner. Suspended
  furnace  walls  are usually a combination  of
 insulated   and   air-cooled   construction.
 Insulation reduces heat loss,  maintains heat
 storage  in  low temperature  zones,   and
 protects the external parts of the incinerator
 from  excessive   heat.   In  high-temperature
 zones, insulation  may be reduced or omitted
 with  reliance on  air-cooling. Suspended wall
 and roofs, usually with a refractory depth  of
 9 in., have the added advantage of permitting
 localized   repair  of  damaged  areas.    In
 conventional    bearing   wall    or   arch
 construction,   complete   reconstruction   is
 often required in making repairs.
  The primary combustion zone is the section
 of  highest  refractory   maintenance.  The
 destructive  influences   on  refractories  are
 excessively   high   temperatures,   flame
impingement,   thermal   shock,   slagging,
spalling,  abrasion from  stoking tools  and
 sliding  or tumbling solid  waste, and erosion
 from  high  velocity  gases  with  entrained
 particles.  Refractories  of  super  duty   or
 equivalent quality best meet the physical and
 thermal requirements as listed above.
  The high abrasive areas  immediately above
 the grate line (where slagging is also likely  to
 occur)  and  the charging  area  frequently
 require  a dense  refractory  such  as silicon
 carbide or  high  alumina brick. Where lower
 temperatures  and  less  wear  occur  as   in
 subsidence  chambers  and stack,    a lower
 quality refractory may be used.  Acid-resistant
 refractories and  mortar  should be used  in
 areas subject to corrosion.
  Spalling and slagging are common forms  of
 refractory  destruction.   Spalling  is   the
 breaking  away of the  refractory,  usually  of
 the outer surface, because of internal thermal
 stresses   developed    through   differential
 expansion.  Slagging  is a form of destruction
 that  occurs from the  buildup  of a layer  or
 deposit of flux on the refractory surface. This
 flux  is   composed  of oxides  of sodium,
 potassium, iron,  calcium, and other elements
 from the burning waste. The increased weight
 of  this bonded  and  fused layer of buildup
 causes the  refractories  to fail. Failure  may
 also be caused by differential expansion and
 contraction between  the  bonded  slag layer
 and  the  refractory.  Slag formation can also
 cause  damage   by   interfering  with  grate
 movement.    Mineralogically   stable,   high
 melting point refractories that  are  dense,  of
 low   porosity and high  strength,  are most
 resistant to slagging and spalling.
  Water  tube  wall   furnaces  are  made  of
 closely spaced steel tubes welded together to
 form a continuous wall with water or steam
 circulating through the tubes. The water tube
 wall  furnace  offers  greater  control  over
 temperatures   and   provides   an   air-tight
 enclosure.  These  furnaces have  been  used
 successfully in the  power industry and  in
 some European incinerators for many years;
however,   their  installation   in   municipal
incinerators in the  United States  has been
limited.
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                Other Aspects

  Auxiliary  Fuels.   It  is  desirable  to  have
auxiliary fuels available for (1) furnace warm
up;  (2)  promotion  of primary  combustion
when  the  solid  waste is  wet  or does  not
contain  an  adequate  Btu  content for good
combustion;  (3)  completion  of secondary
combustion  to  ensure   odor   and  smoke
control; (4) supplementation of heat for heat
recovery units when the supply  or heat value
of the solid waste is not sufficient.
  Auxiliary  fuel is  usually  gas or oil. Burner
location  depends  on  the purpose  of  the
auxiliary fuel.  The  use  of auxiliary  fuel has
not  been  common practice  in the  United
States,    and    consequently,   further
investigations  are needed  to determine the
best locations for auxiliary fuel burners.

  Starting the Furnace.  When an incinerator
is started, the operating temperature of 1,400
to  1,800 F should  be reached  as quickly  as
consistent  with good practice,  which varies
with   the   incinerator    design  and   the
refractories. Incinerators with induced draft
fans  usually  reach  operating  temperature  in
less  than  1  hr.  Natural  draft plants may
require more than 4 hr. Plants with suspended
wall construction require  as  little as half an
hour for heating refractories.
  If  new  refractories  are   installed,   the
manufacturer  should  be  consulted  for his
recommendations on  refractory  curing  and
furnace  preheating. To prevent  damage to
new refractory  linings,  drying  or curing  is
usually necessary. This  preheating period  is
long and  gradual, often requiring several days.
               REFERENCES

1.  HEANEY, F. L. Furnace configuration. In Proceedings;
       1964  National Incinerator Conference, New York,
       May 18-20, 1964. American Society of Mechanical
       Engineers, p. 52-57.
2.  STENBURG, R. L., R. P. HANGEBRAUCK, D. J. VON
       LEHMDEN, and A. H. ROSE, JR. Field evaluation
       of combustion air effects on atmospheric emissions
       from  municipal incinerators. Journal  of the Air
       Pollution  Control Association,  12(2):83-89, Feb.
       1962.
3.  PEARL, D. R.  A review of the state  of the art of
       modern municipal incineration system  equipment.
       Pt. 4, v.  4.  In  Combustion  Engineering, Inc.
       Technical-economic  study of solid waste disposal
       needs  and  practices.   Public  Health   Service
       Publication   No.   1886.  Washington,  U.S.
       Government Printing Office, 1969. p. 17. (In press.)
4.  AMERICAN   PUBLIC   WORKS   ASSOCIATION.
       Municipal refuse disposal. 2d ed. Chicago, Public
       Administration Service, 1966. p. 168.
                                              37

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                                      CHAPTER IX
                RECOVERY AND  UTILIZATION OF HEAT
  The concept of the recovery and use of heat
 produced  during  incineration   has  always
 intrigued engineers  and  municipal  officials.
 Unless the heat  is used, it is wasted—either to
 the atmosphere  or to a heat exchange system.
 In  Huropean  municipal incinerators,  the use
 of heat  recovery equipment is now common
 practice.  In  contrast, relatively  few   U.S.
 municipal incinerators practiced heat recovery
 for other than in-plant use.
  Because heat recovery and water cooling of
 incinerator furnaces reduce  the volume of gas
 to  be  cleaned  and  hence  the  size  of air
 pollution control  equipment  needed,   they
 have  been advocated  as  a  means to effect
 possible  savings  in the cost of air  and water
 pollution  control  equipment.  The  trend
 toward more  effective and  costly pollution
 control  equipment  increases the  economic
 feasibility  of heat  recovery. The increased
 heat  content  of municipal  solid waste  also
 enhances  the  economic  feasibility of  heat
 recovery. The justification for installing  heat
 recovery equipment in most incinerators is
 based on obtaining sufficient income from the
 sale of steam or power  to offset the additional
 cost that results from utilizing excess heat.

          Heat Recovery Systems

  Heat is recovered by heat  transfer from hot
gases  or flames to steam or hot-water systems.
Four  basic  designs have been used: (1) waste
heat boiler systems with tubes located beyond
conventionally  built  refractory  combustion
chambers;  (2)  water tube  wall  combustion
chambers;  (3)  combination water  tube wall
and  refractory  combustion  chambers;  (4)
integrally constructed boiler and water tube
wall combination.
  The  amount  of excess air required differs
significantly  in  the  operation  of these four
types.   Refractory-lined  chambers  usually
require 1 50 to  200 percent excess air whether
waste heat recovery  is practiced or not.  Water
tube wall  chambers usually need 50 to 100
percent excess  air. Low excess  air reduces the
volume of flue  gas to 50 or 60 percent of that
from  refractory-lined   furnaces,   increases
recoverable heat,  and  reduces  the size  of
necessary air pollution control equipment.
  Any  of  these four systems  of waste heat
recovery eliminates  the need for evaporating
large quantities of spray water or adding large
quantities of cooling air to reduce the exhaust
temperature  to the  600-F range needed by
most air pollution equipment.
  Theoretical   efficiency   of  the   recovery
process  may  be  as  great  as 70  percent,
depending  on   the  type  of heat  recovery
equipment utilized.  Steam production ranges
from 1  to as much  as  3.5 Ib per Ib of solid
waste burned because of variations  in excess
heat available from the solid waste.1'2
  Another  method  of  heat  recovery  is  a
flue-gas-to-air heat  exchange located  at  the
exit  of the incinerator chamber. This method
is inefficient because the temperature of the
gas-to-air  exchange  metal  must  be held  at
moderate   levels  to   prolong   its life.  The
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metallic  alloys necessary for a gas-to-air type
of  exchange  are  expensive  and  require
excessive maintenance.
  In heat recovery operations provisions must
be  made for cleaning  the  boiler tubes and
blowing  out the  soot to correct the problem
of  tube  fouling  caused by  fly  ash deposits
and,   under   some   conditions,   slagging.
Increasing the space between the water tubes
can reduce fly ash clogging of gas passages.
  External corrosion of  boiler tubes caused by
chlorides and other chemicals on the fire side
of  the  tubes  will increase  with the  rising
volume  of  plastics in municipal  solid waste,
resulting in greater maintenance costs.


       Application for Recovered Heat

  In  the   United   States,   most  engineers
hesitate  to  design  systems  to reclaim  waste
heat from  incinerators  because of the added
costs  of  heat  recovery  equipment,  the
variability  of the heat  value of solid wastes,
and the  difficulty of matching the supply  of
waste heat to the demand for heat. Matching
the  heat output  of the incinerator to the
demand  presents a serious problem. In most
cases,  other sources of steam, hot water,  or
electricity  must  be available to  supply any
deficiency because of either increased demand
or  a  drop  in  output  from  the  incinerator.
When the demand  for reclaimed  heat cannot
be  met  by the incineration  of solid  waste,
large  capacity  auxiliary fuel burners located
near the  boiler can provide the heat recovery
system with additional  heat as needed.  Since
an  incinerator must burn a  daily quota  of
solid waste of varied heat content, the output
is  usually  more  or less  than the  demand.
Provisions   must  be  made,  therefore,   to
dissipate  excess heat.
  Excess  steam can  be dissipated  by  heat
exchange through water-cooled or air-cooled
condensers.  Condensers increase initial and
operating costs, and exhausted steam must be
replaced    by  treated   feedwater,   which
increases the cost of feedwater treatment and
storage facilities.
  Many U.S.  incinerators with heat recovery
equipment use recovered heat for in-plant use
only.  These  plants  use recovered  heat to
generate  electricity,  supply  hot  water,  and
heat  the  incinerator  plant  during   cold
weather.  Recovered heat has also been used at
one plant for desalting sea water for in-plant
use and for supplying steam power within the
incinerator  plant  and   to  nearby  sewage
treatment plants.
  Several  U.S. incinerators  supply  steam to
heating systems  and  to institutions such as
hospitals.   The  sale  of  steam   to  power
generation plants is  also possible. The most
practical   means of  using  waste  heat is to
supply steam to a large  power system with a
minimum demand greater than the incinerator
can produce. Under these  conditions, steam
does not have to be wasted when the demand
is  at  a   minimum,  and   fluctuations in
incinerator   steam   production   are
accommodated  by  other  sources, such as
steam plants.


          Manpower Requirements

  Manpower  requirements for an incinerator
system with waste heat recovery are  usually
greater than  for a conventional  incinerator.
Additional personnel  are required to operate
and maintain boiler water treating equipment,
steam condensing equipment, boiler auxiliary
fuel  pumps, condensate   pumps,  etc.  The
personnel  operating  the   heat  recovery
equipment must be skilled and,  in some
instances, licensed.


                Economics

  The decision to practice heat recovery  at a
municipal incinerator should be  based on a
careful study of additional  costs incurred and
of the monetary return resulting from  the sale
or use  of  the  recovered   heat. The study
should also carefully consider whether there
                                           39

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is,  in  fact,  a  buyer  for the  waste  heat
recovered.
  The   sale    of    steam    requires
an  incinerator site close to the buyer because
of  the high  cost  of distribution and  loss of
pressure.  Steam prices of SO.25 to $0.50 per
 1,000 Ib, which can be expected, would bring
returns of  SO.50  to S3.50 per ton  of  solid
waste  burned,  assuming steam  production
from  1  to  3.5  Ib  per  Ib  of  solid  waste
burned.3
  The  generation  of electricity  from  solid
waste for sale to power utilities has not often
been practiced  in the  United  States  mainly
because power  of the dependability required
by  the utility companies  cannot be produced
economically by solid waste incineration.
  The  price  realized  from  the  generated
electricity  may  range  up to  10  mills  per
kilowatt hr (kwhr).  Considering variations in
available  heat  and   heat  recovery  process
efficiency, the income  derived  from the sale
of electrical power may range  from $1.50 to
$5.00 per  ton of  solid waste.  These  values
were calculated  using a steam power  cycle
efficiency  of  25  percent  that would  yield
7,300 kwhr per 100,000 Ib of steam, a steam
generation  rate of  1  to 3.5 Ib per Ib of solid
waste burned,  and  an  electricity value of 10
mills per kwhr.3
                       REFERENCES

1.  STABENOW, G.  Performance and design data for large
       European refuse incinerators with heat recovery. In
       Proceedings; 1968 National Incinerator Conference,
       New York,  May 5-8,  1968.  American Society of
       Mechanical Engineers, p. 278-286.
2.  SHEQUINE, E. R. Steam generation from incineration.
       In   Proceedings;   1964  National   Incinerator
       Conference,  New  York,  May   18-20,  1964.
       American  Society   of  Mechanical  Engineers,  p.
       90-94.
3.  COHAN,  L.  J.,  and J. H. FERNANDES. Potential
       energy  conversion  aspects of refuse. Presented at
       American Society of Mechanical Engineers Winter
       Annual  Meeting, Pittsburgh, Nov.  12-17, 1967.
       ASME Paper No. 67WA/PID-6. 7 p.
                                             40

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                                     CHAPTER X
                   INSTRUMENTATION  AND CONTROLS
  Instrumentation  is the equipment used to
indicate and record physical conditions, such
as weight, temperature, position, flow, time,
speed,  and voltage. Instruments monitor but
do  not change the conditions of operation.
Controls  are   mechanisms   that   change
conditions of operation, such as a valve that
can change flow direction or a switch that can
turn on a motor.1
    Uses of Instrumentation and Controls

  Process   Controls.   Before   process
conditions can  be controlled,  manually or
automatically, they must be  measured with
precision  and reliability. Through intelligent
application  of  instruments,  these process
conditions may be measured in a manner that
will  effectively  aid  in  the control  of the
incineration process.
  Instrumentation  for an incineration process
is  essential because of the variability of the
many  factors  involved  in  attaining  good
combustion. As the heat content of the solid
waste  varies, changes  in  the combustion
process   are   necessary.   Instrumentation
indicates these variations so that automatic or
manual control adjustments can be made.
  Protection  of the  Environment. Sensing
environmental   pollutants   and   adjusting
operating conditions to reduce the pollutants
to acceptable levels are important applications
of instrumentation and  controls.   Although
with present, pollution control technology not
all   environmental  pollutants  are   fully
controllable by  operational changes,  several
applications hold  promise  or have  proven
their success. For example, the proper use of
instruments and controls that  maintain  a
steady,  high temperature in  the  secondary
combustion zone ensures that odor-producing
organic  matter in the gas stream is completely
oxidized   to   innocuous   compounds.   In
addition to air pollution control applications,
instruments can serve to sense the  pollution
loading  of waste waters.

  Protection  of Equipment.  Most  safety
instruments are  employed to  detect  and
sound an alarm or to activate a control when
equipment is  in danger of damage.  This  is
particularly true for detecting undergrate fire,
overheating of the furnace, or backfires in the
charging chutes.
  Overheating of the furnace chambers or hot
gas ducting can cause  serious damage in  a
short time. Temperature sensors with  audible
and visual alarm systems should be employed
to signal these dangers. Increasing overfire air,
reducing underfire air, and reducing feed rate
are control methods used to reduce  furnace
temperature. Adjustments can be manual, or
the heat sensing instruments can  activate an
automatic control.
  Failure   of  the  cooling  water   supply,
resulting from clogged nozzles, pump  failure,
electrical power  failure,  or lack of water,  can
quickly  damage  the flue gas cleaning system
and fans.   Automatically  activated  auxiliary
water supply and bypass ducting are desirable
control  provisions for such emergencies.
  Loss of electrical power can cause extensive
damage  to  the plant. Several incinerators have
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  standby  auxiliary   power   supplies   with
  gasoline,  diesel.  or  turbine  engines. When
  power   failure    occurs,   instrumentation
  activates an automatic  cut-in  of an auxiliary
  power system  to prevent damage.
   Data   Collection.  Data   provided   by
  instrumentation can  be used for  evaluating
  incinerator operation  and  for designing future
  incinerators. This information frequently aids
  design engineers in evaluating the  effects of
  design changes and in trying  to identify the
  causes of a  malfunctioning incinerator. Data
  on    plant    performance    should   also
  demonstrate  compliance  with air  pollution
  control requirements.


      Controlling the Incinerator Process

   Types  of  Control  Systems.  A  control
 "system" must have four  basic elements: (1)
 the  standard of desired performance; (2) the
 sensor   (instrument)  to  determine  actual
 performance; (3)  the capability to compare
 actual versus desired performance (error); and
 (4)  the control device to  effect a  corrective
 change.  If these elements  are  integrated  into
 an automatic system that controls the process
 to a  set  standard  (such as a household
 thermostat that holds 70 F  temperature), a
 closed  loop  or automatic feedback  control
 system  is  formed.  If,  on the  other hand,
 control  is  effected  by making a change  and
 then  observing  the result (such as  steering a
 car),  the system is an open  loop, or manual
 system.
  Present  municipal  incinerators   generally
utilize  their  instrumentation  in  conjunction
with  open  loop control  systems,  although
there   is  increasing   use   of  automatic
closed-loop  control  systems  for  controlling
furnace temperatures and furnace draft.1
  In  an open loop  control system, the signal
from  the instrument may be presented to the
operator in one of several forms. Perhaps the
most  informative is  a  continuously  recorded
graphic display, which permits the operator to
 observe the most recent reading as well as the
 previous  reading  to  determine   whether
 process conditions must be changed. Graphic
 displays  also  establish accurate,  permanent
 record for  future analysis. Where the operator
 does   not   have  to   draw  conclusions  or
 interpret trends in data,  a simple  indicating
 meter  is sufficient. Alarms or  other  similar
 on-off displays are especially useful where the
 operator   is   not   required    to   maintain
 continuous  watch over readings or where a
 certain value must not be exceeded.
   A  fully  instrumented  control room or at
 least  a central  instrument panel should  be
 provided so that the plant supervisor has, at a
 glance,  an  understanding of  the  facility
 performance. If the central instrument panel
 is  not near the  furnace   operating floor,  a
 separate, auxiliary instrument  control  panel
 may be needed at each furnace. The readout
 on instruments should  be  easy to understand.
 For  instance,  to the  furnace  operator,  the
 volume of overfire and  underfire air  expressed
 as a percentage of maximum  amount of air
 that can  be supplied is more comprehensible
 than the volume expressed in cubic feet. For
 the operator's  convenience, the instruments
 should be grouped on the panel according to
 function and use. Also, related measurements
 could  be  recorded on a  single chart,  i.e.,
 furnace temperatures, excess air, and possibly
 smoke density.  The degree and sophistication
 of instrumentation  depends upon plant size
 and economics.
   Usually   the  indicating and   recording
 instrument  readouts are grouped on a control
 panel centrally  mounted   on  the  operating
 floor, with  a system of warning lights or bells
 to  summon the  operator  when  corrective
 action  must be taken.  A  duplicate  panel of
 critical instruments may  be placed  in  the
 plant  superintendent's  office for additional
 surveillance.
  Very  often recording instruments indicate
the conditions that exist over a 24-hr period
on a removable paper chart. These records can
be very useful in making statistical summaries
                                           42

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of  operating  conditions  and  in  reviewing
operating  conditions that may correlate with
a malfunction.
  Types and Application of Instrumentation
               and Controls

  Types   of   Instruments.  The   physical
parameters and instruments  that can be used
to assist in the operation of an incinerator
include the following.:
1.  Temperatures
—Optical pyrometers for flame and wall
temperatures in the range of 2,200 to 2,500 F
^Shielded thermocouples (Chrome-Alumel)
for furnace temperatures in the 1,400 to
1,800 F range, and iron-constantan in duct
temperatures down to 100 F Gas- or liquid-
filled bulb thermometers for duct
temperatures below 1,000 F and for ambient
temperatures and water temperatures
2. Draft Pressures
—Manometers and  inclined water gauges for
accurate readout close to the point of
measurement
—Diaphragm-actuated sensors where  remote
readouts are desired
3.  Gas or Liquid Pressures from I to
lOOpsi
—Bourdon-tube pressure gauges for direct
readout
—Diaphragm-actuated sensors for remote
readout
4.  Gas Flows
—Orifice or venturi  meters  with differential
pressures measured by draft gauges
—Pitot tubes and draft gauges
5. Liquid Flows
—Orifices with differential pressure
measurement
—Propeller-type dynamic flowmeters
—Weirs
6. Electrical Characteristics
—Voltmeters, ammeters, and wattmeters.
7. Smoke Density
—Photoelectric pickup of a light beam across
the gas duct
8. Motion
—Tachometers for speeds of fan, stoker, or
conveyor drives
—Counters for reciprocating stokers and
conveyors
9.  Visual Observation
-Vidicon closed-circuit television cameras for
viewing furnace interiors, furnace loading
operations, or stack effluents
—Peep holes in furnace doors
—Mirror systems
10.   Weight
—Motor truck platform scales for measuring
the quantity of incoming solid waste and
outgoing residue, fly ash, and siftings
—Load cells for automatically weighing crane
bucket contents
  Application   of   Instruments    and
Controls. Temperature  measurement is one of
the  major  uses  of instrumentation  at an
incinerator. Temperature should  be measured
at various locations throughout the  furnace
and   gas    passages.   These   include   (1)
temperature of incoming air; (2) temperature
of gases  leaving  combustion  chamber;  (3)
temperatures at settling chamber outlet; (4)
temperature at cooling chamber outlet;  (5)
temperature at dust collector inlet and outlet;
and (6) stack temperature.
  Gas temperature in   the furnace are often
controlled  by  increasing  or  decreasing  the
amount of  underfire   and  overfire air. The
control  system  can  be  either  manual  or
automatic. Some  automatic control  systems
not  only  adjust the amount of overfire  air,
but  also adjust the amount of underfire air
needed to maintain a specific  ratio with the
overfire air.
  Underfire  air can  be controlled so that the
flow of air remains constant even though the
underfire   air  pressure   varies   with   the
characteristics- of the solid waste on the grate.
The  proper  flow and  placement of underfire
air promotes combustion  of solid waste on
the grate  and  reduces  the amount of fly ash
particulates carried into the gas stream. Total
underfire  and  overfire air  flow should be
                                          43

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  measured and recorded; and the percentage of
  each   to   the  total   flow should  also  be
  indicated.
   Changes  in  the  amount of overfire and
  underfire air cause the furnace  pressure  to
  vary.   To  maintain   the  negative  pressure
  necessary for proper  operation,  the furnace
  draft  must be controlled. The control  can  be
  done  manually or automatically by  adjusting
  the speed  of the induced draft fan and the
  chimney  draft.  Draft pressures  should  be
  measured  at  the  following  locations: (1)
  underfire air duct; (2) overfire air duct; (3)
  stoker compartments; (4)  sidewall  air duct;
  (5) sidewall  low furnace  outlet; (6)  dust
  collector    inlet  and   outlet   (pressure
  differential);  and  (7) induced draft fan inlet.2
   The  hot  exhaust gases leaving the furnace
 must  be cooled  to 500 to 700  F  to avoid
 damage to many types of collectors and  to
 the induced draft  fan.  The gases can be  cooled
 by spraying with  water or by dilution  with
 cool   outside  air.  The  proper amount  of
 cooling fluids needed  can  be  regulated by a
 temperature  activated  control  system.  A
 control system should  be installed  to open an
 emergency  bypass  in  case  the  exit gas
 temperature exceeds a safe  limit. This system
 should also activate an alarm.
  Multiple  unit  cyclone  collectors  operate
 best at certain gas velocities. Because  of this
 characteristic,  the number of units should
 vary  with  the  velocity  of the gas  passing
 through the furnace. Since  the gas velocity is
 in  proportion to  the   speed of the  induced
 draft  fan, fan speed can regulate the number
 of units needed.
  Smoke   density    can   be    monitored
 continuously  to check compliance  with air
 pollution  requirements.  The  photoelectric
 pickup of a light  beam across  a gas duct can
 be used to measure participate density  in the
 exhaust  gas. The  monitoring  device  can be
 ideally   located   between   the  particulate
 collectors  and  the  induced draft fan.  The
 fouling  of  lenses  with smoke is  reduced
because the negative pressure existing in this
 area provides  good  operating conditions for
 the device.
   An    incinerator   should   include   the
 instrumentation necessary for determining the
 weight  of  incoming  and outgoing material;
 overfire and underfire air flow rates; selected
 temperatures and pressures  in  the  furnace,
 along    gas   passages,  in   the   particulate
 collectors, and  in the stack; electrical power
 and water consumption  of critical units; and
 grate speed.
  Operational Problems Involving Instruments

  Carefully    written   specifications  for
 instrument   type,  quality,   and   location,
 followed by proper installation and routine
 testing and preventive maintenance are keys
 to   successful  instrument  operation. Many
 instruments  need  frequent  calibration to
 ensure  accurate and  reliable readings. Dust
 can also interfere with the  working of the
 instruments,  and  the hot   and  sometimes
 corrosive flue gas stream can deteriorate the
 sensing  elements  inside  the  gas  passage.
 Although the instrument responds,  a testing
 program is  necessary  to verify and  maintain
 the accuracy of the readings.
  Repair and maintenance of instrumentation
 often  require  qualified personnel. Contract
 services  should be used if qualified instrument
 repair   personnel  are  not  available  at  the
 incinerator.  Incinerator personnel, however,
 should   be  trained  to identify  and  correct
 everyday  problems   such   as  clogging  of
 transmission lines, fouling  and damaging of
 sensing  devices,  and  improper charting  and
 inking.   A  maintenance  and repair service
 contract  to  correct  daily  problems is  not
 warranted when the expense and the time lag
 from  reporting  the  malfunction  to  its
 correction are considered.
  The incinerator personnel should  be trained
 in the use and interpretation  of data received
 from the instruments. Even  if the  operators
 do  not  use  the  data directly, knowing its
intended use  may  motivate  the operators to
obtain an accurate  reading.
                                           44

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                Future Needs

  Improvements in and  wider application of
instrumentation and controls hold  promise
for  upgrading  routine  operations  and for
lowering  the operating  cost  of incinerators.
Although   the   application  of  present-day
instrumentation and  control technology can
improve the state of the art, new concepts as
well as designs  and applications in controlling
the combustion process are needed. Certainly
the need for improvements in measuring and
controlling the weight input into the furnace
is   recognized.   An  improved   device  for
monitoring smoke and particulate emissions is
also needed.  Further research is  also needed
to understand the limitations of instruments,
to ascertain the best instrument locations, and
to  better  correlate  the instrument readings
with incinerator performance.
               REFERENCES

1.  PEARL, D. R. A review of the state of the art of
       modern municipal incineration system equipment.
       Pt. 4,  v. 4.  In  Combustion Engineering,  Inc.
       Technical-economic study of solid waste disposal
       needs   and  practices.  Public   Health  Service
       Publication  No.  1886.   Washington,  U.S.
       Government Printing Office, 1969. p. 25-27. (In
       press.)
2.  STICKLEY,   J.   D.  Instrumentation  systems  for
       municipal refuse incinerators. In Proceedings; 1968
       National Incinerator Conference, New York, May
       5-8,  1968.  American  Society  of  Mechanical
       Engineers, p. 303-308.
                                              45

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                                      CHAPTER XI

          INCINERATOR  EFFLUENTS AND THEIR CONTROL
   Improper  design  and  operation  of  an
 incinerator can pollute air,  water,  and  land.
 Strict air and water pollution legislation at all
 levels of government, coupled with the  trend
 to locate incinerators close  to the sources of
 solid waste (to reduce hauling cost), requires
 an overall upgrading of the incinerator process
 to ensure that it does not adversely affect the
 environment.
   The   unit   processes    associated   with
 incineration  (Figure   14)   that  can   cause
 environmental pollution, except air pollution
 from  stack  emissions,  are  discussed in this
 chapter. Air pollution  control is discussed in
 Chapter XII.
           Odor, Dust, and Litter

  Operation  of the tipping  and storage  area
 can  cause dust, litter,  and  noxious  odors.
 Odor problems from putrefaction of organic
 materials are especially severe if waste  is  held
 in the storage pit for long periods, and several
 days is not unusual, even in the best managed
 plants.  The  dust  and  odors  generated  can
 cause   extremely    unpleasant   working
 conditions.
  Frequent  sweeping of  the  tipping floor
 effectively controls litter.  Washing  the floor
 with   cleaning-disinfecting   solutions   and
 frequently removing putrescibles from the pit
 floor  aid  in the control of odors and insects.
 Pine oil may  also  be added to the washing
solution as an odor  masking agent.
  Fenthion,   diazinon,  naled,  dimethoate,
ronnel,  and malathion are among the effective
insecticides for  control of  flies  and  other
insects.  These  residual  toxicants  may  be
applied  directly  to  the  floor  and   lower
portion of the walls of the tipping  area and
the charging area with a simple,  inexpensive
garden sprayer. Most of these insecticides are
available as bait in granular form that may be
sprinkled on the  floors. An extensive  list of
pesticides   and   instructions    for   their
application has been compiled.1
  Odor and fly control are  facilitated if the
storage pit  is divided; the separate  sections
can be alternately emptied and cleaned. Dust
and  litter can be partially  controlled with
water  sprays  that  are intermittently used
when the dust level is high.
  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 facilities,  but  allows
drainage to surface waters or sanitary sewers.
The    pollution    is   considered    minimal
compared with that  of other process waters.
Even  so,  these waters should be conveyed to
an onsite or offsite treatment process.
  Many dusty,  odorous operations in  industry
are fully enclosed and internal air is processed
through  air  purification systems.  One fully
enclosed transfer station is utilizing activated
charcoal  filters  to  purify  the  air.2   Such
innovations may  have application to odor and
dust  control of solid  waste  tipping,  storage,
and  charging  in  incineration.  In  Europe,
strategically placing combustion  air intakes
within an enclosed tipping area has met with
some success in controlling dust and odor.
                                             46

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ODOR    DUST
   LITTER
                          (AUXILIARY
                      AIR  FUEL)
                                                              PLANTS  WITHOUT
                                                           AIR POLLUTION CONTROL
                                                          AIR AND/OR WATER
                                                                                                          GASES
                                                                                                           AND
                                                                                                        ENTRAINED
                                                                                                          SOLIDS
                       DRYING
                        AND   COMBUSTION
                      IGNITION
                                             GASES
                                              AND
                                           ENTRAINED
                                             SOLIDS
                                               RESIDUE
                             TREATED
                               GASES
  GASES
   AND
ENTRAINED
  SOLIDS
                                                                   FLY  ASH
                                                                   (WATER)
                                                      WATER
    ( FLY ASH
       +
    WATER)
                             FLY ASH
                            < WATER)
                                     RESIDUE   (WATER)
                                                             EFFLUENT   SLUDGE
                                                               WATER   (FLY ASH)
            FLY ASH
                                                  t
                                        LAND   SEWER
                                      DISPOSAL
Figure 14. Diagram of the inplant systems based upon dry fly ash collection and conveying from cooling and collection operations. Alternatives for
                                  wet collection and conveying shown in parentheses.

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          Residue from Combustion
                  Fly Ash
   Residue  consists  of  all  solid  materials
 remaining  after  burning.  It  includes  ash,
 clinker, tin  cans, glass, rocks,  and  unburned
 organic substances.  Residue from incineration
 of municipal solid waste commonly is 20  to
 25  percent  of  the  original   solid waste.
 Uncompacted   residue  occupies 10 to  20
 percent of the  original volume  of solid waste
 in the pit.
   Incinerator residue  is permeable  and may
 contain water  soluble inorganic and organic
 compounds.   If water  moves   through  the
 deposit  of   residue,  leaching can occur.
 Pollution  can  occur 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
 and seeps out  at  ground  surface.  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.
  At  the present time,  there are no  specific
 and universally  accepted quality standards for
residue from municipal incineration. Residue
containing less  than  5  percent  combustibles,
measured in  terms of  total dry  weight  of
residue, and having a total volume of less than
 10 percent of the original solid  waste charged
may,   however,  be  acceptable  from  the
standpoint  of  volume  reduction  in  most
locations. The   degree  of  burnout  will  also
affect   the  degree  of  protection   afforded
environmental quality.
  The combustible  content of residue is not
the  only  true   measure  of protection  of
environmental quality. Other tests, still in the
developmental stage, must be used to measure
the potential  of  residue to cause odors, attract
insects and rodents, and pollute water.3'4
  One of the products  of  incineration is fly
 ash. This portion of the residue consists of the
 solid  participate  matter   carried  by  the
 combustion  gases.   Fly  ash includes  ash,
 cinder, mineral dust, and  soot,  plus charred
 paper and  other  partially  burned  materials.
 The size of most fly ash particles ranges from
 120  to  less  than  5  microns.  Distribution
 within  this range is extremely variable. The
 inorganic fraction  of fly  ash is  usually  the
 major  constituent  and  consists  mostly of
 oxides  of  silicon,  aluminum,  calcium, and
 iron.
  The collected fly ash may be transported in
 a water slurry or handled  in a dry state. Fly
 ash process water has large amounts of solids
 and a low  pH (Table  7).  Because  of these
 characteristics,  sluicing water   should  be
 treated before  final disposal. Usually it can be
 treated with  the  residue process water. Dry
 fly ash,  which is  difficult  to handle, can be
 easily  picked  up and scattered  by the wind.
 At the incinerator plant, dry fly ash should be
 stored in suitable closed containers.  If stored
 in the open, the surface of  the ash pile should
 be  kept moist. When transported  to  the final
 disposal  site,  fly  ash  should  be in  closed
 containers   unless    intermixed    at   the
 incinerator with the moist residue.
  Fly  ash that is  open-dumped is a  potential
 source of pollution.  Left uncovered, dry ash
 can  create a dust problem  and can also be a
 source  of water  pollution  because  the ash
 contains water  soluble  compounds.  Sanitary
 landfill   methods    are    often   necessary,
 therefore, to dispose of fly ash.


               Process Water

  Almost  without exception, all  incinerator
plants  utilize water for residue quenching. In
addition,  many plants  use water  for wet
bottom  expansion  chambers,  for  cooling
charging  chutes,  for  fly  ash sluicing,  for
                                          48

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                                                                   TABLE 7
                                               CHARACTERISTICS OF' INCINERATOR WASTE WATER*
Characteristic

pll
Dissolved solids, mg/1
Suspended solids, mg/1
Total solids (% volatile)
Hardness (CaCO3) mg/1
Sulfatc (SO4) mg/1
Phosphate (PO4) mg/1
Chloride (Cl) mg/1
Alkalinity (CaCO3) mg/1
Five-day BOD at 20 C
Plant It
Residue quench
Max
11.6
9.005
2,680
53.6
1,574
430
55.0
3,650
1,250
-
Min
8.5
597
40
18.5
216
110
0.0
50
215
-
AVK
10.4
3,116
671
36.3
752
242
23.3
627
516
-
Plant 2f
Residue quench
Max
11.7
7,897
1,274
51.6
1,370
780
212.5
2,420
1,180
-
Min
6.0
1,341
7
10.5
112
115
1.0
76
292
-
AVK
10.5
4,283
372
31.2
889
371
23.5
763
641
-
Plant 3f
Residue Quench
Max
11.8
7,929
1,888
47.4
1,438
565
225
1,940
1,290
-
Min
9.4
901
72
17.8
574
115
2.5
128
337
-
AVK
11.0
3,894
653
26.6
904
300
33.8
868
682
-
Plant 4-|-
Residue quench
Max
11.8
5,993
5,476
57.6
1,462
830
127.5
944
749
-
Min
6.0
1,214
14
11.3
282
125
0.5
172
192
-
Avg
10.1
2,551
879
34.6
739
242
23.9
393
465
-
Fly
Max
6.5
9,364
398
_
2,780
1,350
15.0
3,821
28
13.5
Plant Sl-
ash effluent
Min
4.8
7,818
208
-
2,440
1,125
11.5
3,077
16
6.2
Avg
5.8
8,838
325
-
2,632
1,250
13.0
3,543
23
8.8
Fly
Max
4.7
6,089
2,010
24.69
3,780
862
76.2
2,404
4
-
Plant 6t
ash affluent
Min
4.5
5,660
848
23.26
3,100
625
32.2
2,155
0
-
AvK
4.6
5,822
1,351
23.75
3,437
725
51.5
2,297
1.33
-
   *Data Sources:
Plants 1  through  4: SOLID WASTES PROGRAM.  Report on the municipal solid wastes incinerator system of the District of Columbia. Cincinnati, U.S. Public Health
                  Service, June 1967. 77p.
Plants 5 and 6: Bureau  of Solid Waste  Management. Unpublished data (SW-llts) (SW-12ts). Values were determined from data taken at Ogden, Utah; and Alexandria,
               Virginia.

   |Plant 1, 110 TPD, batch, residue quench only;
     Plant 2, 425  TPD, batch, residue quench only;
     Plant 3, 500  TPD, batch, residue quench only;
     Plant 4, 500 TPD, batch, residue quench only;
     Plant 5, 300 TPD, continuous feed -Fly ash effluent only;
     Rant 6, 300 TPD, continuous feed- Fly ash effluent only.

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 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.  Jens and  Rehm5  reported total
 water  requirements  without  recirculation tor
 a  300-ton-per-day plant with  two  150-ton
 continuous feed  furnaces to  be about 2,000
 gal of water  per ton of solid waste  charged.
 Quenching and conveying used 1,800 gal and
 the wetted baffle  dust  collection system used
 200 gal.  The study  indicated  that  use of a
 recirculation,  clarification,  and  neutralizing
 system reduced  the  total water needed from
 2,020  to 575  gal per ton of solid waste.5
   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  gal  of water  per  ton of solid waste
 processed.    With   water    treatment   and
 recirculation,  total  water consumption  can
 often be reduced 50 to 80 percent.
   Studies  have    shown   that   incineration
 process  water   contains   suspended   solids,
 inorganic materials in  solution, and organic
 materials that contribute  to  biochemical and
 chemical  oxygen  demand  (Table  7).6'7  A
 limited study of incinerator  waste  waters
 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.8
  The  studies   indicated   that   incinerator
process waters  can   be contaminated  and,
therefore,    should    not    be   discharged
indiscriminately  to  streams  or  other open
bodies of water.3"5 The most straighforward
control is  the discharge  of these waters 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  treatment  to meet local
standards.
               REFERENCES

1.  NATIONAL  COMMUNICABLE  DISEASE  CENTER.
       1967 National Communicable Disease Center report
       on   public  health  pesticides.   Pest  Control,
       35(3)13-14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34,
       36, 38,40, Mar. 1967.
2.  ROEDER, W. F. Carbon filters control odors at refuse
       transfer station. Public Works, 100(4):96-97, Apr.
       1969.
3.  BOWEN,   I.  G.,  and  L.   BREALEY.  Incinerator
       ash-criteria of performance. In Proceedings; 1968
       National Incinerator Conference,  New York, May
       5-8,  1968.  American  Society  of  Mechanical
       Engineers, p. 18-22.
4.  SCHOENBERGER,   R.   J.,  and P.  W.  PURDOM.
       Classification of incinerator residue. In Proceedings;
       1966 National Incinerator Conference, New York,
       May  1-4, 1968. American Society of Mechanical
       Engineers, p. 237-241.
5.  JENS, W.,  and F. R. REHM. Municipal incineration and
       air pollution control. In Proceedings; 1966 National
       Incinerator Conference, New York, May 14, 1966.
       American  Society  of Mechanical Engineers, p.
       74-83.
6.  MATUSKY, F E., and R. K. HAMPTON.  Incinerator
       waste water.  In  Proceedings;  1968  National
       Incinerator Conference, New York, May 5-8, 1968.
       American  Society  of Mechanical Engineers, p.
       198-203.
7.  SOLID WASTES PROGRAM.  Report on the municipal
       solid wastes incinerator  system of the District of
       Columbia.  Cincinnati, U.S. Public Health Service,
       June 1967. 77 p.
8.  TUCKER,  M. G.  Biological characteristics of incinerator
       waste waters.   Unpublished  graduate  student
       research project  in CE 687 course. University of
       Michigan, Aug. 1967. 15 p.
                                             50

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                                       CHAPTER XII

                           AIR  POLLUTION CONTROL
  Entrained  particulates and some  gaseous
products are the major air pollutants from the
incineration  of  solid  waste. Although  not
extensive,  a  number  of investigators  have
identified the quantities and nature of these
effluents.1"4

             Participate Material

  The  important properties of the entrained
particulars matter,  from the standpoint of its
collection.    are    quantities,    particle-size
distribution,   specific   gravity,   electricity
resistivity, and chemical composition.
  Quantities.  Stenburg   and  Walker   and
Schmitz     ha\ e     quantified     entrained
particulates emitted from refractory furnaces
(Figure 15). The data were based upon studies
of  furnaces  ranging in  size from  50 to 250
tons per  day  employing a variety  of grate
configurations.1'3   An   important  parameter
that appears to  affect furnace  particulate
emission  is  the quantity  of  underfire  un-
utilized in effecting acceptable combustion of
solid waste charged. Values from about lOlb
fly  ash per ton of solid  waste burned to over
60  Ib  per  ton have  been  reported  from
combustion of typical municipal solid waste.
Adjustment  of underfire  air may  partially
control emissions   of entrained  particulate
matter. The data on operating plants indicate,
however,  that adequate combustion of the
solid waste  requires substantial quantities of
underfire  air,  so  that  this  technique  for
reduction  of  furnace  particulate  emission
cannot be   utilized  without   substantially
affecting the capacity of the furnace to burn
solid waste.
  Particle-Size   Distribution   and   Specific
Gravity.  These two properties of particulate
matter are  critical to the performance of most
particulate   collectors   and   essentially
determine  the  level of  sophistication  of air
pollution control equipment required to meet
a given stack emission  objective. Generally,
the larger the size and the higher the specific
gravity,  the  easier  the  particles  can  be
collected. Coarse, high-density materials can
be collected in  simple inertial devices such as
settling chambers and cyclones. Fine, light
materials   require   more    sophisticated
techniques such as high-energy wet. scrubbing.
   j:
   K-
                             FURNACE

                             PD ROCKING GRATE
                             PD TRAVELING GRATE
                             PD RECIPROCATING GRATE
                             PD BATCH FEED

                             PD TRAVELING GRATE
         I   III	|
                                         1,000
             UNCERFIRE AIR (SCFM SO FT GR4TEI


      Figure 15.  Entrained particulate emissions.
                                          51

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 fabric  filtration, or electrostatic precipitation.
 Generally, the percentage,  by weight, of fly
 ash  less  than   10  microns   in  diameter
 determines   whether   simple    or    more
 sophisticated   collection   techniques   are
 required.
   Data on typical particle  size  distribution,
 specific  gravity, and combustible content of
 entrained particulates leaving the furnaces of
 large   (125-   to   250-TPD)  continuous-feed
 refractory  furnace  incinerators  are   shown
 (Table   8).3   The  values  were  typical  of
 entrained  particulates  from  three different
 refractory  furnaces with capacities ranging in
 size  from 120 to  250  tons per day  and
 burning   typical   municipal  solid   waste.
 Because  the nature of the waste  charged and
 the  furnace  conditions  materially   affect
 particle  size   distribution,  caution must  be
 exercised    in   generalizing   from   this
 information.  Nevertheless, if high collection
 efficiencies are  to be  obtained, substantial
 quantities of  material in the size  range below
 10 microns must be collected.
   Electrical Resistivity.  Electrical resistivity
 of the  fly ash is the property of prime interest
 when    electrostatic   precipitators   are
 considered for participate  collection.  High
 resistivity particulates cause disturbances 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 and takes on  a positive
 charge.  The particle  is  then repelled  by the
 positively  charged  collecting  electrode; this
 can  cause the  particle, particularly  if it is
 large, to reenter the gas stream.
  The optimum range for efficient operation
 of an electrostatic precipitator lies between
 104  and  1010 ohm-cm.  Thus, to  select the
most  suitable  air  pollution equipment, the
 resistivity  of  the  fly  ash  must  be known.
 Typical   resistivity-temperature   curves   of
 entrained    particulates   leaving    large,
 continuous   feed   refractory   furnace
 incinerators  were charted  by Walker (Figure
 16).3


                  TABLE 8
 PROPERTIES OF PARTICULATES LEAVING FURNACE
Physical analysis
Specific gravity
(gm/cc)
Bulk density (Ib/cf)
Loss of ignition at
750 C (%)
Size distribution
(% by weight)
< 2M
< 4 M
< 6n
< 8n

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                                               pollutants  by  incineration  of  solid  waste
                                               appears to be low. The sum of the emission of
                                               nitrogen oxides and sulfur oxides from large
                                               steam-electric    generating    stations,    for
                                               example,  may be 10 to 100  times higher per
                                               ton   of  fuel  than municipal  solid  waste
                                               incineration.  The  principal  exceptions  are
                                               those trace constituents  that can cause odor
                                               in incinerator stack effluents. The specific
                                               composition and odor threshold concentration
                                               of  these  constituents  have not  yet  been
                                               identified.
                                                 Water Vapor Plumes.  The  undesirability of
                                               water  vapor  depends  on   the   importance
                                               attributed  to  the  psychological  effect  of
                                               dense, visible water vapor plumes. In rural or
                                               industrial locations, the psychological impact
                                               of  water  vapor  plumes  may be  small.  In
                                               residential  locations,  the   effect  may  be
                                               significant and  a  critical factor in the overall
                                               plant design.
          O   100 ZOO  3OO 400  5OO  SOO  700

                    TEMPERATURE (F)
   Figure  16.  Bulk  electrical  resistivity  of  entrained
particulates leaving three large, continuous feed furnaces at 6
percent water vapor.
100 percent excess air. The reduced volume
of combustion products per ton of solid waste
burned that  results  from  lower  excess  air
operation  in  water-cooled  furnaces  is  an
advantage when  high efficiency air pollution
control equipment is used.
  In addition to the major gaseous products
of  combustion,  trace  gases  present  in  the
effluent can cause  air pollution either because
of  their odor; their direct effect  on plants,
animals, and property;  or their  interaction
with components of the ambient air to form
undesirable  secondary compounds.  A number
of  these  have been identified  (Table 9).1'4
Compared  with   other major  combustion
processes  that contribute  gaseous  pollutants
to  the atmosphere, such  as  combustion of
fossil   fuel,  the  contribution  of  gaseous
                100   150   200
                 EXCESS AIR (PERCENT)

   Figure 17.  Gross products of combustion per pound of
solid waste.  20 percent carbon remaining in total residue.
Solid waste composition based on Kaiser's analysis. Standard
conditions for measuring gases are 29.92 inches Hg and 70 F
at 60 percent relative humidity.
                                             53

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   Three general situations  are encountered in
 the treatment  of exhaust  gas stream: (1) gas
 cooling   to    temperatures   acceptable   to
 partieulate  emission  control  equipment  is
 achieved without vaporization of water,  i.e.,
 radiation,   dilution,   or   indirect   heat
 exchange-either gas-to-gas  or  gas-to-liquid;
 (2) gas cooling to acceptable temperatures  is
 achieved  either  partially  or  totally  by
 vaporization    of   water,   and   partieulate
 collection  is  dry;  (3)   gas   cooling   and
 participates   collection  is  achieved  by   wet
 methods.


                  TABLE 9
    TRACE GAS CONSTITUENTS IN INCINERATOR
                 EFFLUENT1'4
Gaseous emissions
(Ib/ton)
Aldehydes
Sulfur oxides
Hydrocaibonsf
Organic acidsj
Carbon monoxide
Nitrogen oxides
Ammonia
Typical municipal
solid waste*
23.6 X 1CT4
—
0.8
—
0.51
2.7
—
Mostly branches and
twigs (no garbage)
1.1
1.9
1.4
0.6
-_
2.1
0.3
   *Typical municipal solid waste: Converted from reported
 units in pounds per 1,000 Ib flue gas at 50 percent excess air
 to pounds per ton solid waste based on "typical refuse," as
 established by Kaiser.
   fHydrocarbon expressed as methane.
   ^Organic acids expressed as acetic acid.
  In  situation 1, absolute  humidity  is low
(approximately 0.07  Ib  water vapor/lb dry
gas) since no  water vapor is added in cooling.
Temperatures  of  the  gases  are high (450  to
600 F) so that dispersion capability is good.
Because   of  the  low  humidity  and  high
temperature,  water  vapor plume occurrence
will  probably  be  restricted  to  very  low
ambient temperatures. In situation 2, absolute
humidities  may  be  several  times   higher
(approximately 0.25 to 0.30 Ib water vapor/lb
dry gas) since a substantial amount of water is
evaporated  in cooling the  gases  from stack
temperatures  of  1,200 to  1,800 F down  to
450 to 600 F; however, stack temperatures
are  still high,  dispersion capability is good,
 and  condensate  plumes  will  probably  be
 limited   to   situations   of   low   ambient
 temperature   and    intermediate    ambient
 temperatures  associated  with  high  relative
 humidity. In situation 3, partieulate scrubbers
 saturate  the  gas  with  moisture,  absolute
 humidities   are    high    (under   adiabatic
 saturation  conditions approximately 0.6 Ib
 water/lb  dry gas), and  effluent temperatures
 are  low (in  the range of 175 to  180 F under
 adiabatic   saturation  conditions)   so  that
 dispersion capability  is  poor and condensate
 plumes   will   occur   under   almost   all
 atmospheric conditions.
  Condensate plumes are usually not harmful,
 and  local complaints may possibly be reduced
 by  proper preeducation  and public relations
 regarding water vapor plumes. On the other
 hand, there have been complaints of corrosion
 on   automobiles   resulting from condensate
 fallout  and  of  a  decrease  in  visibility  at
 ground level on roadways, etc.,  that have been
 connected  with   water  vapor  plumes from
 incineration. Thus,  these  potential problems
 must be  given serious  consideration in  the
 design of the plant.

           Desired Emission Levels

  Gaseous Emissions. The principal gaseous
 emissions from incineration are  common  to
 all  combustion  processes:  carbon  dioxide,
 water vapor, nitrogen, and oxygen.  These  are
 all normal atmospheric  constituents, and no
 control is necessary. In recent years, attention
 has  been directed   toward the  control   of
 emission  of sulfur  oxides, nitrogen oxides,
 carbon  monoxide,  hydrogen   chloride,  and
 total  hydrocarbons.   With   the   possible
 exception  of  sulfur  oxides,  no  maximum
 permissible   emission   levels   have  been
 developed,  although  criteria   do   exist   in
 certain  critical  areas on nitrogen oxides and
 total  hydrocarbons.   In  the specific  case  of
solid  waste  incineration   (excluding  open
burning),   emission   of  all  these   gaseous
contaminants apparently is well below present
                                            54

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or contemplated criteria. Thus, at the present
time, and with the exception of the control of
those trace emissions that cause odors,  the
control of other trace gaseous emissions from
incineration appears of minor concern.
  Gas-Suspended   Particulate
Emissions.  Specific   quantitative   emission
limits   on  gas-suspended   particulates   are
becoming  increasingly  prevalent in the  air
pollution codes  of many municipalities  and
States  as well as in the operation of Federal
facilities. These codes may be expressed in a
variety  of ways, such as: (1) total  weight of
suspended particulate  per  unit volume  of
exhaust  gases; (2)  total weight  of suspended
particulate per  unit weight of exhaust gases;
(3)  total  weight  of suspended particulate
emitted   per  unit weight   of solid waste
charged. Further, to prevent  compliance with
emission codes by simple dilution  of stack
gases with air or water vapor, almost all codes
require correction  of these emission limits to
a specific reference condition.
  At the present time,  the most commonly
used units for emission values in incinerator
practice  are  pounds  suspended  solids  per
thousand pounds of dry flue gas corrected to
50 percent excess  air  and grains per standard
cubic foot (29.92 in. Hg and 70 F) of dry flue
gas  corrected to 12 percent carbon dioxide.
The  reference   conditions   of  12  percent
carbon dioxide and 50  percent  excess air are
approximately equivalent for municipal  solid
waste.   Figure    18    gives   approximate
equivalents of the most common units, to 1 gr
per  standard  cu ft of dry gas as sampled,  for
typical municipal  solid waste under various
combustion conditions.
  Some   representative    gas   suspended
particulate emission limits (as they  existed in
early  1968)  have  been summarized  (Table
10).2 In the absence of local regulations, the
code established  by  U.S.   Department  of
Health,  Education, and Welfare should apply
(Appendix B).
  Visual  Emission  Levels.   In  addition  to
provisions    limiting    the    quantities    of
particulate  emission,   many  codes  at  the
municipal and State level  also have  opacity
restrictions —usually   based    upon    the
Ringelmann chart.6  The Ringelmann  number
is   determined   by  a  comparative  visual
observation  of the stack plume and a series of
reference  grids of black lines on  white that,
when properly positioned, appear  as shades of
gray to the  observer. Although the quality of
a plume in equivalent Ringelmann numbers is
not  easy to  determine,  trained observers,
properly positioned in relation to stack, sun,
and wind direction,  can  provide satisfactorily
consistent evaluations.7'8 Water vapor plumes
complicate  observations of stack gases, but
again,   trained   observers   can  distinguish
between water  vapor  and residual  plumes
under selected weather conditions.
  The  trend in  most  codes on  incinerator
emissions based on  Ringelmann is to require
that:  (1)  normal, continuous  plume  quality
not to exceed Ringelmann No. 1; (2) for short
periods not exceeding 3 to  5 min in any one
         PERCENT EXCESS AIR IN FLUE GAS
                AS SAMPLED
   Figure 18.  Dust concentration equivalents for 1 gr/SCF
(29.92 inches Hg and 70 F) dry gas as sampled, as a function
of percent excess air in sampled gas. Conditions are based on
Kaiser's typical refuse with 20 percent carbon remaining in
the residue. Example:  correct 1.5 gr/SCF as sampled at 200
percent excess air to gr/SCF at 12  percent carbon dioxide.
From graph: 1 gr/SCF as sampled at 200 percent excess air =
2.1 gr/SCF when corrected to 12 percent carbon dioxide;
therefore, 1.5  gr/SCF at 200  percent excess air  when
corrected to 12 percent carbon dioxide =  (1.5)(2.1) = 3.15
gr/SCF.
                                             55

-------
 hour, plume quality not  exceed Ringelmann
 No.  2. and (3) plume quality clearly resulting
 from water  vapor  only  be excluded from
 regulation.
   Plume opacity refers to the inability of light
 to pass  through the gas plume  and is usually
 applied  in cases where  the plume is some
 color other  than  gray  or black. Opacity
 readings  are  expressed in  terms  of percent
 visibility through the gas plume.
   From the standpoint of plant design, a basic
 problem arises  from the fact that  the entire
 technology of particulate  collection has been
 based upon  quantitative  reduction in  the
 weight of total suspended materials. Thus, to
 establish the level of control required to meet
 a  given  visual  code,  this  code  must   be
 expressed  in  some  quantitative gravimetric
 units. Consistent  and  general   criteria  for
 correlating gas quality measurements, such as
 Ringelmann    number,    with   quantitative
 emission  in  the case  of incinerators are  not
 yet   available.   Therefore,   the   collection
 efficiency  required  to   meet   a  particular
 Ringelmann number is virtually impossible to
 predict.   Experience  with  large,  coal-fired
 steam generators indicates  that loadings in  the
 range of 0.01 to 0.02 gr per cu ft of exit  gas
 result in  stacks  optically  clear  of suspended
 participates (i.e., less than Ringelmann No. 1).
 Achievement of these stack  concentrations in
 coal  firing requires collector  efficiency  in
 excess of 99  percent by weight. Similarities in
 particle size distribution from coal-fired steam
 generators  and from incinerators indicate that
 efficiencies of this order will be required on
 incinerators   if  completely   clear   stack
 emissions are to be achieved.


            Methods of Control

  Control  of  Odors.  The  best  approach  to
 the control of odors generated  in  the drying
and  combustion process  is maintenance  of
 adequate   retention  time  and   sufficient
temperature  to  ensure  complete combustion
of hydrocarbon vapors to carbon dioxide and
                 TABLE 10
    TYPICAL PARTICULATE EMISSION CODES FOR
 COMBUSTION OF SOLID WASTE IN A 250-TON-PER-DAY
   INCINERATOR BURNING TYPICAL SOLID WASTE





Agency
U.S.Deptof
Health,
Education,
and Welfare,
regulations,
for Federal
Installations
Bay Area APCB
San Francisco,
California
Reg. 2,
Chapter 1
State of
New Jersey
(proposed
Chapter XI)



Emission
limit
(as written)
0.2 gr/std
dry cu ft
corrected
to 12%
C02


0.2 gr/std
dry cu ft
corrected
to 6% O2

0.1 gr/std
dry cu ft
corrected
to 12% CO 2
Approximate
lb/1,000 Ib
dry flue
gas corrected
to 50%
excess air
0.36






0.36




0.36



equivalent value
gr/std
dry cu ft
corrected
to 12%
C02
0.2






0.2




0.1



water. Elimination of odors from stack gases
demands  that  mixing of  any volume of gas
containing odors must be completed so that
the  required  excess  air  and  temperature
conditions are  reached in every stream of gas.
A  0.5   sec   residence   time  before  the
temperature  of  the mixed  gas  falls below
 1,500   F  is  generally   sufficient.  If the
temperature at the exit of the furnace is kept
above   1,400  F,  temperatures  within the
combustion  chamber will be sufficient to
eliminate odors.
  Another odor control technique is to dilute
the odorous gas in  the atmosphere to a value
below its threshold  odor so it is unapparent to
a receiver. This is achieved through  the use of
stacks of sufficient effective height. Effective
stack  height is a function of both the actual
stack height and plume rise as the gases leave
the stack. The  height a plume will rise above
the  stack  is   a  function  of the  ambient
temperature and the  gas  temperature,  exit
velocities  of the stack gases, and the stability
of the  atmosphere. If the  threshold value of
                                            56

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any  identifiable  odorous  gas  is  known,
methodology is available for estimating the
maximum quantitative emission that will keep
odorous  gas below the threshold  value at the
nearest   receiver.  Presently,  however,   this
technique for controlling odors  is  not being
used  for two  reasons:  (1)  the ability  to
eliminate odors by proper process operation;
and  (2)  the  absence of identifiable odorous
contaminants and their threshold  values.
  Data  on  107  existing batch  feed plants
indicate  a  maximum  stack height, above
grade, of 250 ft, a minimum of 39 ft, and an
average  of 133 ft.5  On 44  continuous feed
plants,  the  values  were: maximum  250 ft,
minimum 25 ft, and an average of 145 ft. The
advances that have been made in the use of
meteorological   methods and data  in  the
design  of  stacks  as  pollutant dispersion
devices  appear applicable  to the  design of
stacks for incinerator plants. This suggests the
desirability   of  competent  meteorological
consultation to determine stack heights.
  Control   of  Gaseous  Emissions   from
Combustion.  Both nitrogen  oxide and sulfur
oxide   emissions   occur   in  solid   waste
incineration,  but the amounts per ton of 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 0.16 percent by weight2 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 incineration,  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 restrictions present or
anticipated.
  Restrictions  on nitrogen  oxide  emissions
from fossil fuel combustion have  not yet been
formulated. Nitrogen oxide emissions per ton
of fossil fuel are over 10  times  greater  than
those in an incinerator. Therefore, it appears
unlikely   that   this  contaminant  will  be
regulated  in incinerator  plants  in  the  near
future.
  Some concern  has been expressed about
emissions  of hydrogen chloride (HC1)  that
might  occur as  a  result  of incineration  of
certain plastics. Hydrogen chloride is toxic to
the eyes and  respiratory system, and if the
amounts released during  incineration were
great enough,  a health  problem would exist.
  The  plastic  polyvinyl  chloride is  found in
increasing amounts in municipal solid waste.
When  it  is burned,  hydrogen chloride  is
released, and emissions of 2.7,  2.2,  1.4, and
6.8 Ib per ton of solid waste incinerated were
measured at four New York incinerators.9 If
hydrogen    chloride   emissions  become   a
problem, control will be necessary, but since
this  gas  is  highly  soluble  in  water,  it can
probably  be effectively removed by water
scrubbers.
  Control  of Suspended Particulate Emission
from Combustion.  The following is a brief
discussion of the various types of participate
collection   systems,   their   performance
capabilities  based upon objective test data,
the state of the art of their development with
respect  to  application  to  incinerators,  and
some general indication of their capital cost.
Cost data are based upon plants in the range
of  150-  to 200-ton-per-day rated  capacity.
The  particular  type  of control system used
will depend primarily on the desired level  of
control, taking into account both quantitative
and  optical emission criteria,  and on the
overall  cost to own and operate  the system.
   Types of Collectors.   Settling Chambers.
The simplest  and oldest  form  of particulate
particulate   collector  is the settling  chamber
with either a dry or wet bottom. With the
exception of a very few plants  equipped  with
some form  of sprays or baffle  system within
the settling chambers, this was the only  type
of collector used in incineration plants in this
country before about 1953 or 1954. Available
test  data on  the settling  chamber indicate
efficiencies  in the range of 10 to 34 percent
by  weight.3'10'11 Since 1961  and  1962, the
                                           57

-------
 use of settling chambers in their simplest form
 as the only participate collection device  has
 become  essentially obsolete since they  are
 unacceptable  as  the  principal means of air
 pollution control.
   Wetted   Baffle-Spray   System. Another
 form  of participate  collection  device is  the
 wetted  baffle  or baffle spray system. These
 systems   usually    consist   of   vertical
 impingement baffle screens that are  wetted
 with  water by  flushing sprays or overflow
 weirs. There may be one  or more screens in
 the  collection  system. Participate  removal
 efficiency has  been measured over a range of
 10  to  53  percent  by  weight  at  several
 different installations.3'10  Pressure drop is in
 the range of 0.3 to 0.6 in.  of water gauge.
 Water consumption is  in the range of 0.5 to
 2.0 gal per min per ton of rated capacity. One
 installation, which uses a spraying section and
 secondary baffle  section, claims an efficiency
 of 69.4  percent;  pressure  drop  and other
 operating data are unavailable.1 :
  These  wet spray or wet baffle systems have
 been used  on over half of the  incinerators
 installed  since 1957.  Their installed  cost is
 approximately  $0.02 to $0.04 per actual cu ft
 per   min   of  gas  at  the  collector  inlet
 temperature (1.800F).
  Cyclones  and Multiple-Cyclones.  Batteries
 of  relatively large diameter (24  to  40 in.)
 parallel cyclones, with involute  or scroll type
 entry connections, as  well  as small diameter
 (9 to 12 in.) multiple tube vane type cyclone
 collectors have been used in about 20  percent
 of the incinerator installations built or under
 construction since  1957. Although there is a
substantial  amount of  test data available  on
the  performance  of  this  type of collector,
little  has been published.  Unpublished data
confirm    published    data   that   indicate
efficiencies   in   the  range   of   60   to  65
percent.11 There is little information on  the
performance  characteristics  of   the  small
diameter vane type collectors. Experience in a
few   installations  seems  to  indicate  that
plugging  of this  type  collector  can be a
 problem   when   used  downstream  ot  gas
 cooling systems involving the use of water.
 Experience with cyclones seems to favor the
 use of the involute type in tube size above 24
 in. Maximum reliable efficiency appears to be
 in  the range  of 70 to 80 percent.12  Pressure
 drop  is in the range  of 2.5  to  4.0 in.  water
 gauge.
  Installation cost for cyclone collectors, not
 including  such  auxiliaries  as  foundations,
 supporting steel, flues,  and ash removal, is in
 the range  of $0.12 to $0.25 per actual cu ft
 per min of gas treated.
  Wet Scrubbers.   Approximately  20  percent
 of  the  incinerator  plants  built  or under
 construction since 1957 have been equipped
 with  wet  scrubbers. Wet scrubbers differ in
 their design and operation from wetted baffle
 collectors  principally  in that capture of  the
 entrained  participates  is  accomplished  by
 direct  intimate contact of  the  participates
 with   the  water   itself  rather   than   on
 water-flushed   impaction   surfaces.   The
 particulates  collide with water  droplets to
 effect  capture.   The   water droplets  and
 impacted   particles   coalesce   into   larger
 droplets (greater than 1,000 microns)  that are
 easily collected in  an inertial collector.  The
 water droplets are  generally formed by either
 atomizing  the liquid into the gas stream or by
 allowing the gas stream to tear  coarse water
 droplets into  the smaller droplets needed  for
 high  efficiencies. With atomizing units, most
 of  the  operating  energy is expended  in
 pumping the water through the spray nozzles;
 gas pressure drops  are generally low. In units
 where the gas stream  tears the  water apart,
 most of the  operating energy is  expended in
 moving   the   gases   through   the    unit;
 comparatively little energy is  consumed in
 pumping   water.   In   scrubbers,  collection
 efficiency is primarily related to  total energy
 consumption whether  it  is energy used to
 pump  liquid or  energy  used to  move  gas.
Again, published test data are unavailable on
this  type  collector, but analysis  of their
operating principles and comparison of their
                                           58

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known   performance   on   suspended
participates  with   characteristics similar  to
those from incineration indicate an efficiency
capability in the range of 94 to 96 percent at
pressure drops in the range of 5 to 7 in. water
gauge.
  Water requirements range from about 5 to
15 gal per 1,000 actual cu ft  per min  of gas
treated. Pumping  power is based  on these
figures,  although   actual   makeup   water
requirements  can   be   much  lower   where
recirculating  and   clarification  systems  are
utilized.   Another   characteristic  of wet
scrubbers  is  that  the gases at the collector
outlet will be saturated  with water vapor, an
important consideration in  relation to water
vapor plumes from the stack.
  Because they operate below the dewpointof
many   trace    corrosive   constituents   in
incinerator flue  gases, wet  scrubber systems
require corrosion-proof  construction. The
installed  cost  for the base  collector without
auxiliaries   such    as   foundations,   water
treatment   systems,  pumps,   and   piping
ductwork  is in the  range of $0.25 to  $1.25
per actual cu ft per min of gas treated.
  Electrostatic   Precipitators.  Electrostatic
precipitators  operate on  the  principle  of
electrically    charging   the   suspended
particulates   and    depositing   the  charged
particles   on  the   surface   of  a  collecting
electrode. To remove the particles from the
collecting electrode, the collecting surface  is
vibrated, although water sluicing can be used
in certain applications.
  The electrical  properties  of  the  suspended
particles,  the moisture  content of the  gas
stream, and  the temperature of the  gas stream
affect  precipitation   operation.   Adding
moisture  can lower the high  resistance  of
inorganic particles. The tendency of carbon to
lose  its charge  before  collection  can cause
some problems, but these can be  overcome.
Proper insulation  of the precipitator,  which
eliminates   the   internal   dewpoint
condensation, can  control  corrosion  caused
by moisture in the gas stream. Temperature of
the  gases  is very  important to precipitator
operation because the resistivity of entrained
particles is extremely temperature dependent.
Precipitator operation is best at temperatures
between 470 and 520 F.13
  Electrostatic  precipitators have no ability to
collect  gaseous contaminants except as these
gaseous contaminants may be absorbed on the
particulates removed.
  Electrostatic  precipitators have been used in
Europe for a number of years in incinerator
plants that  recover heat. Auxiliary fuels such
as coal or oil are used under most operating
conditions.14 Efficiencies in  the range of 96
to   99.6  percent  have  been   achieved  at
pressure drops  below  0.5  in.  water gauge.
Electrical power requirements are in the range
of 200 to 400 watts per 1,000 actual cu ft per
min of  gas  treated.  Inlet  temperatures are
usually in the range of350to700F.
  During   pilot    plant   feasibility   tests,
efficiencies  of  89  to  94.4 percent  were
obtained  on suspended particulate  removal
from  a  220-ton-per-day  continuous   feed
furnace.] 5   Electrostatic  precipitators  have
not yet been operated on a full  scale basis in
the  United  States, but  several  new plants
under  construction  will  utilize  electrostatic
precipitators with design efficiencies in the 90
to 98.5 percent range. The basic advantage of
the  electrostatic  precipitator   over  other
particulate collectors is its high efficiency at
low   operation   cost   (pressure   drop  and
electrical  power input)  and its  ability  to
achieve  these  efficiencies in a  dry system
without  creating potential  water  pollution
problems.   Typical    installed    cost   for
electrostatic   precipitators,   not   including
auxiliaries  such  as foundations,  supporting
steel, flues,  and fly ash removal,  is in  the
range of $0.85 to  $1.45  per actual cu ft per
min of gas treated.
  Fabric Filters.  Except for a  single pilot
installation  on   one  municipal  incinerator,
fabric  filters have  not yet  been applied  to
incinerators. Although they  are used by many
industries,  their  use at incinerators must be
considered experimental.
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   Fabric filters  literally filter the suspended
 particulatcs from gases in a manner similar to
 the  operation  of  a  vacuum  cleaner.  The
 predominant filtering  media is  the  dust eake
 itself, which accounts  for the high efficiencies
 obtainable  (usually  in the 99.9'x?  +  range).12
 The  dust  cake, once it  has  been formed,
 essentially  filters all particles as the  gases pass
 through the  pore  openings in the cake; these
 openings are no  bigger  than  the  smallest
 particle in the gas stream.
   Their utilization  for a given  application is
 almost  always  based  on  consideration   of
 temperature,  moisture  content of the  gas
 stream,   pressure   drop  characteristics   of
 available filtration media, and the service  life
 of  these   filter  media.  Fabrics,  such   as
 fiberglass and high-temperature synthetics,  are
 available    with   continuous    operating
 temperature  capability up  to  about  550  F
 Many varieties  exist,  and  their costs differ
 principally  in relation to  their temperature
 capability and resistance to chemical  attack.
 Another  consideration  in  the selection   of
 fabric filters is the porosity of the filter cake
 that is  built up  on the  fabric  surface during
 normal operation.  Cake  porosity depends on
 moisture,   particle  size  distribution,   and
 physical and chemical  characteristics of  the
 entrained participates.  The typical  operating
 pressure drop for fabric filters would be in  the
 range of 4 to 7 in. water gauge.  Initial cost of
 fabric  filters that  might  be  applied   to
 incinerator  operations,  based upon the use of
 treated fiberglass bags,  would be in  the range
 of $0.75 to $1.50  per  actual cu ft per min of
 gas treated.
  Factors in  the   Selection  of  Particulate
 Collectors.  Matching  the  type  of collection
 equipment  needed  to  meet a particular  air
 pollution  control   objective   is  illustrated
(Tables 11 and 12).
  Unless  furnace   operation    is   to   be
significantly  restricted,  particularly   with
respect  to underfire air, even the most lenient
 quantitative  emission  code  cannot  be met
 with  settling  chambers or  wetted  baffles,
                  TABLE 1 1
   COLLECTION EFFICIENCY REQUIRED TO MEET
        VARIOUS EMISSION LIMITATIONS*

     Code requirement       Approximate % efficiency*
(Ib particulate/1,000 Ib flue gas)       to meet code
0.85#/l ,000* («' 50% excess air
0.65#/1,000# r«' 50% excess air
0.20#/1,000# (<" 50% excess air
       74
       80
       94
   *Based on 32 Ib of fly ash per ton of solid waste charged
entering the collector.
                  TABLE 12
    MAXIMUM DEMONSTRATED CAPABILITY OF
            VARIOUS COLLECTORS
   Type of Collector
Maximum demonstrated
    efficiency (%)
Settling chambers
Wetted baffles
Cyclone collectors
Direct impaction scrubbers
(wet scrubbers)
Electrostatic prccipitators
Bag filters
34
53
70-80

94-96
99
99+
either  alone  or  in  combination.   Cyclone
collectors can meet 0.85 Ib per 1,000 Ib at 50
percent  excess  air  and  probably  can meet
intermediate  codes.   When  codes   require
emissions below 0.65  Ib per  1,000 Ib at 50
percent  excess  air;  the only  demonstrated
alternatives are direct  impaction  scrubbers,
electrostatic precipitators, or bag filters.
  Control  of Water  Vapor Plumes.  Water
vapor  plumes may not  be directly  harmful
and are,  in  most cases, excluded from opacity
regulations. Droplet  fallout or  visible vapor
plumes,   however,   may   constitute   an
important nuisance factor.  Usually  the plume
problem  is associated with high efficiency wet
scrubbers, so  the  first  method of controlling
condensate  plume  is  to use dry gas cooling
and  collecting  techniques.  If  other  factors
dictate the  use  of high-efficiency  scrubbers,
two alternatives are possible: (1) extract heat
from  the hot furnace gases before  collection
and  reintroduce  the  extracted  heat after
collection as stack gas reheat. Such a scheme,
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which  involves  the  use   of  gas-to-gas  heat
exchangers, reduces both absolute and relative
humidity  of  the  stack  gases  and improves
their dispersion  capability at the same  time
(such    systems    have    been    used    on
incinerators);  (2)  dehumidify  the saturated
flue  gases by  subcooling  below  the normal
scrubber   outlet    temperatures.    Cooling
requires  the  use  of  a packed cooling  tower
and a  source  of cooling water below the wet
scrubber    exhaust   gas    temperature.
Dehumidification  of  the   stack  gases can  be
achieved   by   this  method,  water  can  be
recovered  and  recycled,   and  the operating
horsepower of high  pressure drop  fans  can be
reduced. Dehumidification systems have  been
used with success in other applications, but
have not, as yet, been utilized on incinerators.
                 REFERENCES

  1. STENBURG, R. L., R. P. HANGEBRAUCK, D. J. VON
        LEHMDEN, and A. H. ROSE, JR. Field evaluation
        of combustion ail effects on atmospheric emissions
        from municipal  incinerators.  Journal of the  Air
        Pollution  Control Association,  12(2):83-89, Feb.
        1962.
  2. KAISER,  E.   R.  Refuse  composition  and flue-gas
        analyses   from  municipal   incinerators.   In
        Proceedings; 1964 National Incinerator Conference,
        New York, May 18-20, 1964. American Society of
        Mechanical Engineers, p. 35-51.
  3. WALKER, A.  B., and F. W. SCHMITZ.  Characteristics
        of   furnace   emissions   from   large,
        mechanically-stoked   municipal  incinerators.   In
        Proceedings; 1966 National Incinerator Conference,
        New York, May 1-4, 1966. American Society of
        Mechanical Engineers, p. 64-73.
  4. STANFORD  RESEARCH  INSTITUTE. The  smog
        problem in Los  Angeles County.  Los  Angeles,
        Western Oil and Gas Association, 1954. 134 p.
 5.  STEPHENSON, J. W., and A. S. CAFIERO.  Municipal
       incinerator   design   practices  and  trends.  In
       Proceedings; 1966 National Incinerator Converence,
       New York, May  1-4,  1966. American Society of
       Mechanical Engineers, p. 1-38.
 6.  KUDLICH, R.  Ringelmann smoke chart. Rev. by L. R.
       Burdick. U.S. Bureau of Mines Information Circular
       7718  (Rev.  of  1C  6888).  [Washington], U.S.
       Department of the Interior, Mar. 1955. 4 p.
 7.  CONNER, W.  D.,  and  J. R. HODKINSON.  Optical
       properties and visual effects of smoke-stack plumes.
       Public Health Service  Publication  No. 999-AP-30.
       Cincinnati, U.S. Department of Health, Education,
       and Welfare, 1967. 89 p.
 8.  U.S.  DEPARTMENT OF  HEALTH,  EDUCATION,
       AND  WELFARE, PUBLIC  HEALTH  SERVICE,
       DIVISION  OF  AIR  POLLUTION.  Equivalent
       opacity—a   useful  and  effective  concept  for
       regulating visible air pollutant emissions.  Presented
       at  East-West  Gateway   Coordinating  Council
       Hearings on the Proposed Interstate Air Pollution
       Study  Recommendations,  St.  Louis, Sept. 27,
       1966. 13 p.
 9.  CAROTTI.A.  Unpublished data, 1968.
10.  JENS, W., and  F.  R. REHM.  Municipal incineration
       and air  pollution control.  In Proceedings;  1966
       National Incinerator Conference, New York, May
       1-4,   1966.  American  Society  of Mechanical
       Engineers, p. 74-83.
11.  MANDELBAUM, H.  Incinerators  can meet tougher
       standards. American City, 82(8):97-98, Aug. 1967.
12.  FERNANDES, J. H.  Incinerator air pollution  control
       equipment. Pt.  5, v.  4. In Combustion Engineering,
       Inc.  Technical-economic  study   of  solid  waste
       disposal needs and practices. Public Health Service
       Publication   No.    1886.  Washington,   U.S.
       Government Printing Office, 1969.  705 p.
13.  BUMP, R. L.  Conditioning refractory furnace gases for
       electrostatic   precipitator  application.   In
       Proceedings; 1968 National Incinerator Conference,
       New York, May  5-8,  1968. American Society of
       Mechanical Engineers, p. 23-33.
14.  BUMP, R. L.  The use of electrostatic  precipitators for
       incinerator gas  cleaning in Europe. In Proceedings;
       1966  National  Incinerator Conference, New York,
       May 1-4, 1966. American  Society of Mechanical
       Engineers, p. 161-166.
15.  WALKER, A. B.  Electrostatic fly ash  precipitation for
       municipal  incinerators—a  pilot plant study.  In
       Proceedings; 1964 National Incinerator Conference.
       New York, May 18-20, 1964. American Society of
       Mechanical Engineers, p. 13-19.
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                                     CHAPTER XIII

                          ACCEPTANCE  EVALUATION
   Acceptance evaluation is an appraisal ol an
 incinerator (that  can be formed) based on
 inspection and tests during construction and
 again  at the completion of the project. The
 primary purpose  of  this  evaluation  is the
 determination  that  all  provisions  of the
 contract   are  being   met  and   that  the
 incinerator   performance   meets  the
 specifications.  The  method  or  means of
 making   the  acceptance   evaluation  are
 provided for in the terms of the contract.
   Construction materials and  workmanship
 are inspected and evaluated from beginning of
 construction through  completion. Individual
 mechanical components of the system such as
 fans,  grates, valves, etc., are  certified  by the
 manufacturer  but  should also be inspected
 and checked on the job. The performance of
 the incinerator, however, cannot be evaluated
 until   all   components of  the system are
 assembled  within the completed structure, at
 which time a performance or operational test
 is  conducted.  Tests   are  commonly  run
 simultaneously on all components  of the
 incinerator system.
  Many  municipal   incinerators   now  in
 operation  were built as a "package deal." The
 incinerator   contractor   supplied   design,
 equipment,   and   facility  construction,  to
 produce   an   end   result    of   "system
 performance"  specifically  detailed  by the
 owner. The contractor was responsible for all
 phases  of  design,  component   selection,
 assembly, construction, and final performance.
 Because    incinerators  are   now    more
 complex,  the current  trend  is  to employ
services of a consulting engineer to design the
incinerator  system  to  meet  the   owner's
requirements.  In  this  case,  the  consultant
specifies each  component and  how  each is
related  to the other. The contractor,  then, is
responsible for construction and assembly of
equipment and  components in accord  with
the  details  of  the   designer's  plans   and
specifications  and may  not be required or
expected  to  ensure that the incinerator  will
meet  performance type requirements; this is
the responsibility of the  design consultant. In
the absence of an expressed guarantee by the
contractor that the finished job will perform
as specified, all the contractor is  responsible
for is that he has complied with the plans and
specifications  prepared by the consultant. If
unsatisfactory  performance  is  a  matter  of
negligent  design,  the  consultant can  be  held
responsible.
  Whether   the  incinerator   is  built   by
"consulting  design"  or as  a "package deal,"
evaluation  must  be  conducted  throughout
construction. Defective construction materials
and  faulty  construction  methods must be
uncovered and corrected at this stage because
often corrections cannot be made  later. Even
where   corrections   are   possible   after
construction  is  completed, they  are  always
expensive.  Therefore,  the   owner   should
obtain the services of a contractor who has
demonstrated   his   capabilities.   Both   the
contractor and  the  design  consultant  are
responsible for acts of negligence.
  Equipment selection  is often determined by
the manufacturer's willingness  to guarantee
and   accept   responsibility  for  equipment
performance. Manufacturers, however, seldom
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make blanket  guarantees.  In  air  pollution
control, for example, a manufacturer will not
state  that  his  equipment  will  produce  a
visually  clear stack effluent.  He will, however,
usually  be  willing  to  guarantee  that his
equipment will remove a fixed percentage of
particulates based  on standard  tests. This
distinction should  be considered in writing
specifications.
  Before performance specifications become
part of the bid proposal,  they  should  be
reviewed  by  the  community's  engineering
staff  to  determine  that  the  specified
performance will meet the  antipollution and
other requirements of the community. Legal
aspects  of the contract  should  be reviewed
with   particular   emphasis   on  the
responsibilities and liabilities of all  parties
involved.
  A "shakedown period" between completion
of the incinerator and final acceptance  testing
or evaluation  is usually required.  This  period
commonly ranges from 30 to 90 days. Since
there may be a lag period between completion
and acceptance,   the   effective  date  of
mechanical  equipment warrantees should be
agreed upon and included in  the contract.
  The   incinerator  designer   and   plant
personnel  commonly   participate  in  the
acceptance evaluation  test.  The  acceptance
test should be conducted under the range of
conditions  expected  to occur during normal
operation.  In the acceptance evaluation of a
"package deal,"  it is advisable to  bring in an
unbiased third  party to determine contract
compliance.
  The  acceptance procedure varies with the
community. Usually a  community does not
take  over  operation   until  the  plant  is
accepted; however,  the community  should
have personnel  present  for  training.  If the
acceptance test fails, a  specified time should
be  given  to  rectify  the  situation  before
penalities or liquidation damages are applied.

  Today, there are no consistent performance
tests to  be used  for  municipal  incinerator
acceptance procedure.  The methodology for
performing  various   tests,   such   as  stack
sampling  for  particulates and  determining
residue  and  effluent  water  characteristics,
have not been  standardized. To  meet  this
need, the  American Society of  Mechanical
Engineers  and  the  Bureau  of Solid  Waste
Management  are currently  developing tests
and procedures for evaluating incinerators.
                                             63

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                                     CHAPTER XIV

    SOLID WASTES THAT REQUIRE  SPECIAL  CONSIDERATION
  Solid waste may contain combustible items
 such   as   discarded   furniture,  mattresses,
 automobile  and truck tires, tree stumps, logs
 and  large branches,  demolition lumber, and
 industrial boxes, crates, and skids. Solid waste
 may also contain a variety of noncombustible
 items  such  as  stoves,  refrigerators,  water
 heater tanks, and metal furniture. These items
 are classified as "bulky solid  waste." Because
 they   are   too   large,   would  not   burn
 sufficiently  in  the normal  process  time, or
 might   damage   or   interfere  with  the
 incinerator  mechanism, it is impractical and
 often   impossible   to   process   bulky
 combustible wastes at conventional municipal
 incinerators.   Municipal   solid  waste  also
 contains materials that in  their collection and
 disposal  may be  potentially  injurious  and
 therefore deserve special consideration. These
 are  classified  as  "hazardous  wastes"  and
 include radioactive materials, toxic chemicals,
 and highly flammable  or  explosive materials.
 Other  municipal  wastes that  require special
 consideration include  obnoxious substances,
 such  as  pathological wastes,  and  various
 sludges.


             Bulky Solid Waste

  Some municipalities  dispose of their bulky
 waste by  sanitary land-filling; some practice
 open burning of the combustible bulky items.
Where long haul distance is involved or where
land  is  scarce,  land disposal of bulky waste
 can  be  quite  expensive.   Because  it  is
potentially    dangerous   and   causes   air
pollution, open  burning  is a poor solution.
Some communities have evaded the problem
by  refusing to  collect  bulky  items.  This
approach results in illicit  dumping or open
burning.

     Special Incinerators for Bulky Waste

  Several  cities  are  now   using   special
incinerators for  oversized burnable  waste.1
The incinerators are refractory lined and have
a refractory hearth. Charging is by the batch
method and burning time is varied to suit the
materials.  Auxiliary  fuel has  been used  to
ignite the  solid  waste, and  in  some cases, to
ensure  complete combustion; however,  the
bulky waste usually burns readily without the
assistance  of  auxiliary fuel.  Charge  size is
•limited  by furnace dimension  and maximum
size of any  object  is  controlled  by  the
dimensions of the door opening.
    Size Reduction of Bulky Solid Waste

  Preparation of combustible bulky items for
burning in a conventional incinerator requires
reduction  to  fragments  that  can  be  easily
handled mechanically and that will be burned
in the normal process time.  Equipment used
for size reduction has included shears, impact
mills,  hammermills, flailmills, and  chipping
devices such as the "wood hog."
  Because  of the wide  variety of items that
constitute   bulky   solid  waste   and   the
heterogeneity   of   materials  making  up
individual  items,  size reduction has been of
only  limited  success.  Some  impact  mills,
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hammermills,  and  chippers  are capable of
processing  presplit  logs and  presplit stumps,
wood pallets and crates, demolition lumber,
and large wood furniture to suitable size for
burning.  Generally,  this equipment has  not
been   satisfactory   in   reducing   heavy
metal-framed   burnable   furniture    and
mattresses containing heavy steel framing and
springs.  Some shearing equipment can reduce
bulky   waste  containing  steel,  such   as
innerspring  mattresses,  to  fragments of  size
suitable  for acceptable burnout when  these
fragments  are  intermixed with other solid
waste.  The noncombustible portion of the
processed material  does not interfere  with
incinerator mechanism.
  Although  the capability of size  reduction
equipment  for bulky solid  waste  has been
demonstrated,  the  practicality  of  some of
these methods has  not been established. An
exception  is  shredding  equipment  for  tree
branches;   this    equipment   has   been
successfully used for years.
  The  operation  of  most heavy equipment
used for size reduction is extremely noisy and
dusty.  Heavy, fast-moving  parts are inherent
to  most  of  the   processes.   Where   such
equipment  is  used,  extreme care  must be
taken to provide for the worker's safety. Most
operations   require  dust  control and  noise
insulation.

             Hazardous Wastes

  Hazardous  wastes  are   those  that  are
potentially injurious such as highly flammable
or explosive materials, toxic chemicals,  and
radioactive  materials. Many hazardous wastes
can be routinely handled in small quantities at
the  incinerator without  creating  problems.
For  example, when  a half-full  gallon-can of
volatile  paint  is heated in an incinerator, the
only result would probably be the lid blowing
off.  The burning of the  small  quantity of
released  paint would  create no problems.
However, a 5-gal drum  of volatile  paint or
other   flammable    liquid   could   cause
considerable damage to the furnace and could
injure  the  workers.  Pressurized  cans,  so
common today, generally cause no damage to
the furnace  when  they "pop." They can,
however,  be dangerous  to workmen when
metal fragments are blown through furnace
openings.  Other  hazardous  wastes include
gasoline, kerosene,  oil, and other flammable
liquids;   sawdust   and   wood   shavings;
flammable  plastics,  especially  when  finely
divided;   rubber   dust;   and   flour   and
magnesium shavings.
  Because it would  be practically impossible
to  prevent  all   hazardous materials from
entering the incinerator, precaution must be
taken to minimize danger. Large quantities of
hazardous   wastes   can   be   avoided  by
prohibiting those  generated by industry or by
making special provisions for them if they are
accepted.    A   safer,  and    often   more
economical,  method   is  to   establish   a
partnership   between  industry  and  local
government for central disposal of industrial
wastes.
  Even where hazardous industrial wastes are
prohibited,   municipal   incinerators   will
occasionally receive dangerous materials from
the   residential   community.   The   waste
collectors  will often be in the best position to
detect possible hazardous wastes and alert the
incinerator personnel. If suspected hazardous
wastes are inadvertently dumped into the pit,
they  must be removed  or mixed  with  the
contents of the storage pit  until they are at a
safe concentration.
  A municipal incinerator should not accept
radioactive wastes. The handling and disposal
of all radioactive  wastes must be carried out
in accordance with  recognized  standards  and
procedures outlined by the Atomic  Energy
Commission or other responsible agency.

             Obnoxious Wastes

  Obnoxious wastes  are  those that  are so
highly objectionable and unpleasant from the
standpoint of appearance,  health effects, or
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 odor that  they  should not be handled in the
 conventional  municipal incinerator  without
 special  provisions.  Certain wastes generated
 by hospitals and medical  laboratories can be
 obnoxious  and  dangerous (disease bearing).
 These  include  anatomical  wastes,  surgical
 dressings, sputum cups, stool specimens, and
 other test specimens.  Most hospitals dispose
 of these wastes in pathological incinerators.
   Slaughterhouses,  butcher shops, and other
 food processing plants generate quantities of
 obnoxious wastes that have a high moisture
 content,  are  highly  putrescible, and  may
 contain   pathogens.   Most   slaughterhouses
 dispose   of their  wastes  by  special  drying
 equipment  and  incineration. In  many  large
 cities,   wastes  from   slaughterhouses   and
 butcher  shops   are   collected   by   private
 agencies for rendering and  reduction for the
 production of fats, glycerine, detergents, etc.
 Dead farm animals and domestic animals may
 also be collected for this purpose.
   With the exception of small birds and mice,
 dead  animals  are too  large and dense  to be
 consumed  in   the   conventional   municipal
 incinerator process. Some  cities have  special
 batch-fed   incinerators  for  burning   dead
 animals  and obnoxious substances, including
 hospital   wastes.   At   some   incinerators,
 refrigerators are  provided   for  storing dead
 animals   for  periodic   cremation.    Some
 incinerators have access to a  hearth  in  the
 secondary   combustion   zone  where   the
 animals  can be placed  until cremated by the
 hot gases and flame.


       Combined Sewage Sludge—Solid
             Waste Incineration

  Like municipal solid  waste, the  amount of
 sewage in this country is increasing each year.
 The cost of ultimate disposal of sewage sludge
 and associated wastes  is  increasing as  land
 becomes less available. Sludge incineration has
 been  practiced for  many  years for volume
reduction.
  A   method   of   disposal   still   under
investigation is  the  combined incineration of
intermixed sewage sludge, screenings, greases,
and scums with municipal solid waste. Some
cities  in  the   United   States  have  used
combined   solid    waste-sewage   sludge
incineration  methods.2  The  potential  cost
savings is based primarily  on using the excess
heat generated  from burning the solid waste
to dry the partially dewatered sludge and thus
allow  it  to   burn  readily.  Other   potential
savings result  from the use of a single  facility
instead of separate incinerators. Although the
combined   incineration   process    appears
economical, three factors must be considered:
(1) hauling costs; (2) sewage sludge moisture;
(3) waste production rates that affect uniform
blending of the two  materials, each  of which
is variable in itself.
                Conclusions

  There are obviously many more wastes that
require   special   considerations    by   the
incinerator   designer  and  operators.  The
engineer must vary his design according to the
wastes that may be  handled over the life of
the plant.  To do  this, he must have accurate
information on  the quantity and composition
of  the   wastes.   Incinerator  design  and
operation  will  become  increasingly  more
complex  and   challenging  as  communities
strive for the single  method or single  system
capable of handling all wastes.
               REFERENCES

1.  KAISER, E. R. The incineration of bulky refuse. In
       Proceedings; 1966 National Incinerator Conference,
       New York, May 1-4, 1966. American Society of
       Mechanical Engineers, p. 39-48.
2.  BURD, R. S.  A study of sludge handling and disposal.
       Publication   WP-20-4.   [Washington],   U.S.
       Department of the Interior, Federal Water Pollution
       Control Administration, May 1968. p. 289-293.
                                              66

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                                         CHAPTER XV
                                         SALVAGE
  Salvage is the  recovery  of  waste  goods.
Since  most  of  our  solid waste   contain
materials of  value,  waste  disposal  officials
should  consider salvage  of waste materials.
Many  municipalities have  practiced  salvage.
Some   of   these   operations   have  been
profitable; others have become inefficient and
a nuisance.  Thus, the decision  to use salvage
and  reclamation   should  be  based  on  a
thorough  engineering  cost  and  marketing
study. In no case should such an operation
seriously interfere with the major objective of
solid waste disposal.
  The major materials occurring in municipal
solid waste  that may be  of value in a salvage
operation  include  ferrous  and  nonferrous
metals, paper, rags, glass, rubber, plastics, and
food waste.  If  all of the materials  of value
were recovered,  the process  or  operation
would be classified as  "total salvage." Total
salvage  has  been  practiced in the  United
States,   but  generally,  it  has  not  been
successful. In many cases,  "partial  salvage"
has met with variable degrees of success and is
currently being practiced. Partial salvage is  the
selective recovery from solid waste of one or
more constituents that have economic value.
In  connection  with incineration,  the most
commonly salvaged  material is ferrous metal.
  Total salvage in  the United States has failed
because  it   has  been  uneconomical. The
market  value  of   salvage  materials  has
fluctuated  severely  and some fractions have
lost  their value completely. The makeup  of
incoming solid  waste  is   also subject   to
extreme  variation. Materials of value tend  to
disappear from  refuse  when the  market is
attractive.     Schools     and     charitable
organizations   conduct   drives  to   collect
newspapers  and  magazines  or scrap metal.
Where  permitted,   private  collectors   and
scavengers collect metal,  rags,  and paper for
resale. Conversely, when  the market price  is
low, the municipality  will be responsible for
collection and  disposal of larger amounts of
paper.
  Total salvage is a costly operation.  Because
of  the heterogeneity  of solid waste,  the
process requires a great amount of hand labor.
Labor  costs  have  continuously  increased
whereas, generally, the overall market value of
salvaged material has declined.  Mechanization
and   semiautomation   techniques   in  total
salvage   have   not   reduced   labor  cost
sufficiently to justify the process.
  Municipal   officials   are  hesitant  about
investing tax monies in projects as uncertain
as total salvage.  Also, because  many salvage
operations  have  been unsightly  and have
resulted in public health problems, the public
is   also apprehensive  of proposed  salvage
operations. In spite of these uncertainties  and
the poor record of past performances, salvage
deserves further attention. Theoretically,  it  is
an ideal solution to the solid waste problem
and allows conservation of natural resources.
  Partial salvage  has been conducted either
before  or  after incineration.  Rising labor
costs, declining salvage market, and variation
in  solid waste  composition  have  affected
partial salvage in  much the same way as total
salvage.
  Removal   of  some  constituents  before
incineration  may   affect  the  combustion
process.  An  increasingly large portion of
municipal solid waste is paper, which provides
                                            67

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 most of the combustibles at an incinerator.
 Thus,  removing paper would lower the heat
 value of solid  waste and the furnace would
 have   to   be   designed  accordingly.   An
 incinerator   designed    to   handle    only
 nonsalvageable  materials would be inadequate
 to  handle  all  solid  waste when the salvage
 market  fell  too  low   to  justify  salvage
 operations.  Similarly, an incinerator  capable
 of   handling   all   solid  waste  would  be
 inefficiently utilized when a high proportion
 of    the   constituents   are   removed.
 Noncombustibles such as cans and bottles are
 believed  to aid the  incinerator  combustion
 process by  creating voids in the fuel bed, thus
 providing   for  more    uniform  burning.
 Removing  these  items  before   incineration
 might decrease  the burning rate.
  Salvage of metal after  incineration has been
successfully conducted at some  incinerators.
A major advantage of this method is that the
volume of  material to be processed has been
reduced  considerably.  Other advantages  are
that   the   after-incineration   process   is
esthetically  more  acceptable;  the  burning
process  removes  much of  the  undesirable
combustible  material  from  the salvage;  the
primary  disposal process, incineration, is not
dependent on salvage;  and  failure of salvage
equipment or failure  of the salvage  market
will   not  directly  affect  the  incineration
process  for  the  salvage operation  could  be
bypassed and all residue could be disposed of
without   making   major   changes  in  the
operation.
  Including  a    salvage   operation   with
incineration  can  reduce residue volume and
salvage may provide an economic  return. The
success of salvage depends on the size of the
operation,  the  type of incineration,  salvage
plant design  and  operation, the  market for
salvaged  materials, and  the shipping cost  to
the point of usage.

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                                       CHAPTER XVI
                       OPERATION AND  MAINTENANCE
         Management and Personnel

  As  a  community  plans  and  builds  an
incinerator,   it  should  also  plan  for  the
management  and  personnel  necessary  to
operate it.  The  plant  supervisor should be
employed several months before construction
is  completed   so   that   he  can  become
thoroughly   familiar   with   each   major
incinerator  component  as  it  is  installed.
Operating personnel should be obtained early
enough so that they can work closely with
representatives   of  the  manufacturers  and
contractors  when the incinerator  is in the
latter stages of construction and put through
the  acceptance  tests.  In  this  way,  the
incinerator personnel can be trained in proper
operation, maintenance, and repair.
  At the  outset the  management, and  this
includes  the  plant  superintendent,  should
develop a table of organization showing the
number  of  shifts,  number and  types  of
personnel   per   shift,  and  standby   and
maintenance personnel. Several methods of
job classification exist; whatever  method  is
used should have sufficient flexibility so that
incinerator personnel can be used for various
jobs.  Rigid  job titles that tend to limit
operating personnel duties should be avoided.
  Staffing needs vary  with the  size and type
of incinerator,  number of shifts, organized
labor  regulations (including  working hours,
vacations, fringe benefits),  and  the extent of
plant  subsidiary operations,  such  as  heat
recovery  and salvage.  The  total  man-hours
required in efficient operation range from 0.5
to 0.75 per  ton of solid waste processed. This
does  not  include  man-hours  for  residue
disposal and major repair work.
  Management  needs to  provide  sufficient
employment   incentives.    An   acceptable
working   environment,    equitable   pay,
advancement,  opportunities  and  training,
retirement  and  other fringe  benefits, and
employment security are essential.

             Operation Guides

  Flow Diagram.  Every plant  should post  a
scaled engineering drawing, pictorial drawing,
or scale model of the plant, showing all major
components  by  name  and function.  This
diagram or scale model should illustrate how
the solid waste and  its  resulting  gases and
residues pass through the plant, so  that plant
personnel and visitors may readily understand
the  various  components   and how   they
function together.
  Drawings.  The local solid  waste  disposal
operating agency should  have copies of all
engineering drawings,  showing  the  plant and
all its components. At least one set of formal
drawings should be maintained  at the plant
for reference by  operational and maintenance
personnel.
  Operation   and  Maintenance  Manuals;
Equipment  Manuals. Equipment  manuals,
catalogs, and spare parts  lists should  be kept
at the  incinerator  for  quick  reference by
employees. A  manual describing the various
tasks that must be performed during a typical
shift   and  the  safety   precautions  and
procedures for working in various areas of the
plant should also be kept on hand.
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           Performance Records

  Criteria  that may be  used for evaluating
incinerator     operation    are     residue
characteristics   (physical   and   chemical),
volume  and weight  reduction of original solid
waste, amount of pollutants released to the
environment, various operating costs per ton
of  solid waste processed,  and  efficiency of
heat recovery equipment or  other subsidiary
operations. The use of these criteria  require
that the following data  be recorded.
  Incoming   Solid   Waste.  Plant   records
should indicate the  total weight of solid waste
received during each  shift  as  well  as the
number  of  vehicles  arriving,  identity  of
vehicles, and the source and nature of solid
waste received.
  Furnace-Burning  Rate,  Temperature,  and
Air  Flow  Rates.  Furnace operators  should
record  furnace  temperature   at  frequent
intervals  unless   such  data   is  recorded
automatically.   Explanations   should   be
provided for  prolonged  temperatures above
1,800 F or below  1,200 F Grate speeds (or
rate  of   operation)    should   be   noted
throughout   the  shift.  Air  volumes  and
distribution  should also  be reported. All
readings should be  made at least hourly and
any  major  changes  noted.  Some instruments
give indirect  readings  (draft in  inches of
water, grate function in amperes, etc.), and so
such  data  must be interpreted  in terms of
settings  required for good furnace operation.
  Residue.  Operators should record the time
or rate of residue removal.  Residue should be
weighed on the scale as it leaves the plant, and
the  amount  removed  should  be  recorded.
Moisture correction is necessary for  proper
interpretation of residue  weight.  The  dry
weight  of residue  can   be  estimated  by
periodically  obtaining  the average moisture
content.  Residue quality  should be visually
determined and recorded.
  Water    Consumption.  Water    used   for
quenching  and   for   scrubbers  should  be
recorded from  meter  readings  or by other
means at least at the start and end of each
shift.
  Power    Consumption   and
Generation.  Flectncity  may  be  metcrcd at
major units to  pinpoint those  equipment
malfunctions that are manifested  by changes
in    power   consumption.   Power   for
electrostatic  preeipitators and large electrical
motors   should  be   separately  mete red.  If
power is generated,  generator records should
be kept.
  Steam  Generation.   If steam  is  generated,
flow  meters should  be  installed  to record
production.  Hours of operation at specified
rates may be used, as well.
  Stack    Discharges.  Records    of  stack
discharge characteristics  commonly include
smoke   indicator   readings,    Ringelmann
readings, and analyses  from stack samplings
for participate emission.
  Personnel  Records.  Accurate   personnel
time and cost records should be kept so that
incinerator performance can  be evaluated on
the basis of operating cost per ton and on the
basis  of  man-hours  per ton. The direct and
indirect  costs should  be  added to the total
cost of incinerator operation.
  Supplies,  Material,  and Equipment.  All
supplies,  material, and  equipment  utilized in
incinerator operation and maintenance should
be   recorded  and    charged   against   the
incinerator,  even   though   provisions   or
purchases   may   be  made   by   another
department.  Major  incinerator  maintenance
(such as  rebuilding of refractories),  whether
done  by contract or  by  plant   personnel,
should be  recorded  as  cost  items  separate
from  incinerator operation.  Thus,  both  the
cost  of repairs  and maintenance and the cost
of plant operation can be determined.

       Utilization of Recorded Data

  Recorded data  provide  a permanent means
of evaluating incinerator  performance. This
evaluation  is needed  to guide the  day-to-day
operation and  can  also be used for making
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important   adjustments   in   equipment,
operating   procedures,   and    personnel
assignments, and periodic reports to the local
government.

          Maintenance and Repairs

  Records.  A  records  system   should  be
established by  the plant supervisor wherein
periodic  maintenance  of  each   incinerator
component  is  scheduled  to  be  done  by
specific   personnel.   In  contrast,  certain
maintenance,  such as  cleaning,  lubrication,
and adjustment of equipment, may be done
by  operating personnel as part of their daily
or  weekly tasks and need  not be recorded.
Certification   that  maintenance  has  been
performed should  also be recorded. Card files
set  up with an  automatic reminder procedure
will  provide   a    permanent   record  of
maintenance for each item of equipment and
guard  against   omission    of   scheduled
maintenance. Properly  certified maintenance
records, tabs, or seals, may also be affixed to
the equipment  as  maintenance is performed.
Major repairs,  such  as  the  replacement of
refractories,  will   necessarily  be   recorded
separately    Unscheduled   repairs   and
breakdowns should be handled promptly and
carefully  recorded  so that the cause can be
determined and corrected.
  Inspection   and   Repairs. Components
subject  to rapid wear or damage should be
inspected  weekly   at  a  time when  such
components are not being operated. At each
inspection, a thorough report should be made,
including   condition  of  furnace,  repairs
performed, and expectation of future repairs
or major overhaul.  Plant performance records
and   maintenance   files  can  be  used  to
determine when major repairs are necessary.
  When major overhauls are being made, the
units  remaining in service  should not  be
overloaded to  make  up  for the  loss  of
capacity.  The  amount  of  solid  waste
equivalent to   the  "down"  unit's  capacity
should be diverted to an approved disposal
site or to other incinerators. Ideally, extensive
repairs should be scheduled during the season
when waste generation is lowest.
  Plant personnel  will   not  normally  be
expected  to  perform  major  repairs  on
equipment,   building,  or  facilities.   Other
municipal   personnel   may   perform   some
repairs, and certain repairs will require special
contract services.
  When general wear and  tear accumulates to
the  point  that  continued operation  is  no
longer economically   feasible   or prudent
without   major   reconstruction,   the
abandonment  or demolition  of the facility
must  be   considered.   Good  management
demands that such determination be made in
time  to arrange  for the  necessary financing
and  construction of new facilities. Since this
process may take several years, adequate lead
time is essential.  A capable plant operator will
be able to aid in this decision.
  Management should keep abreast with new
development   and   decide   whether   the
incinerator operation  can be improved. The
costs of revisions, expected life of the plant,
temporary disposal alternatives, and financial
considerations  enter  into these  decisions.
Unfortunately,  the  updating  of incinerators
by redesign and  reconstruction has been the
exception rather than the rule.
  In  many instances, incinerators are  built
with provisions for future enlargement  or for
later  addition  of  equipment.  Here  again,
performance   evaluation   will  guide  the
decisions of when to modify equipment or to
enlarge capacity.
  Maintenance    of  Buildings.  Although
certain parts  of  a plant are inherently dirty,
dusty, or  difficult to keep clean,  devices to
reduce accumulation of dust  and dirt,  water,
or debris  should be installed, and personnel
should spend some time during the shift to
maintaining  a  clean  workspace.  Misuse of
employee   facilities, such as  accumulating
salvage items should  not be permitted. In
some  instances,  poor housekeeping  creates
fire  or safety hazards. Lighting fixtures and
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bulbs  should  be   kept  clean  to  provide
acceptable illumination at all times. Auxiliary
lighting equipment should  be maintained for
inspection   purposes   and    for   use   in
emergencies.
  Maintenance  and Repair Costs.  The cost of
proper  maintenance  and repairs  varies  with
the size, type,  and age of the plant but can be
expected  to run between 5  and 10 percent of
the total cost of operation, split about equally
between   labor    and   materials.   Good
management   will   budget   for   annual
maintenance  and   repair  work,   including
periodic   major
modernization.2
                       replacements   and
               REFERENCES
i.
                 European  developments  in  refuse
                 Public  Works,  97(5):113-117, May
   ROGUS,  C.  A.
       incineration.
       1966.
2.  ROGUS, C. A.  Incinerator design. Municipal solid waste
       disposal. Part 3. American City, 77(4): 104-106,
       Apr. 1962. Part 4. American City, 77(5):106-108'
       May 1962.
                                             72

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                                                        APPENDIX A
                          for
    in.oin.era,tor
                      Eric  R. Zausner*


  Effective solid waste management requires  an adequate
information system including data on activity and the  costs
of operation and ownership.  Although a  cost accounting
system represents only one part of the total system, it  does
facilitate  the  collection  and later  utilization  of  the  data
obtained.
  Present information on incineration and its associated  costs
is both  inadequate  and  nonslandardized.  The  proposed
system provides a guide to the type and quantity of informa-
tion to be collected, its classification, and the method of col-
lection.  Incinerator supervisors and heads  of agencies  re-
sponsible for their operations will find the system useful.
  A cost accounting system can aid a community in  con-
trolling the costs  and performance of  its incinerator opera-
tions, as well as aid in formulating future plans.
   Chief, Management Sciences Section, Operational Analysis Branch, Division of Tech-
nical Operations, Bureau of Solid Waste Management.
                             73

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                      System Benefits
   Some of ihe more important advantages are:
 1.  The system facilitates orderly and efficient collection and
 transmission of all relevant data.  In fact,  most of the data
 recorded  is probably being collected already, although per-
 haps only sporadically and inefficiently.  Hence, the added
 cost of installing the proposed system is minimal.
 2.  Reports  are clear and  concise and present  only  that
 amount of data required for  effective  control and analysis.
 They can easily be completed and understood by incinerator
 personnel.
 3.  Interpretation of results and  comparison with data from
 previous  years or from other communities is simplified. This
 allows analysis of relative performance and  indicates  areas
 where corrective action is needed.
 4.  The system accounts for all relevant costs of operation.
 5.  Because the system indicates  high costs and their under-
 lying causes, the supervisor can  control costs  more effec-
 tively.  Similarly, performance and efficiency  may be moni-
 tored and controlled.
 6.  Accountability is superimposed on the system to indicate
 who is responsible for the increased costs.
 7.  The data provided are in a form that aids in short- and
 long-range  forecasting of operating and  capital  budgets.
 Future requirements of equipment, manpower, cash, etc., can
 be  estimated to aid budgeting and planning at all levels of
 municipal goverment.
 8.  The system, with  only  minor  modifications, is  flexible
 enough to meet the  varying requirements of incinerators of
 different sizes.

            Cost Centers and Cost Allocations
  The complexity of incinerator operations requires a break-
 down and description of operations to facilitate analysis. In
 this report,  the  incinerator is assumed to consist of several
interrelated suboperalions, each  of which  is  analyzed sep-
arately. These  suboperations are called cost centers because
 costs are accumulated separately for  each of the major func-
tional activities.  Analysis and control are simplified if ex-
cessive  costs or inefficiencies can be traced to a functional
activity or area of the facility.
                            74

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  The number of cost centers increases as the size and com-
plexity  of operations increase.  More cost centers, however,
require  the  collection of more data and, therefore, increase
costs. For most facilities, four cost centers appear to collect
adequate data without incurring  excessive  collection  costs.
  Three of  the four cost  centers (Receiving and Storage,
Volume Reduction,  and Effluent  Handling  and  Treatment)
are termed  the direct cost centers because  they  can  be di-
rectly associated with certain incinerator operations and unit
processes. The operations included in each follow the process
flow from input of raw wastes to output of effluents (Diagram
I). The  fourth, the Repairs and Maintenance  cost center, can-
not be directly associated with waste processing.  Therefore,
it is separated from  other operations and not shown  in the
diagram.  Because it  incurs a large percentage  of operating
costs, a  separate analysis is needed.
  Although  fewer cost centers would  never be required,
larger operations may require more cost centers.  For instance,
the Effluent  Handling and  Treatment cost center could be
divided into  Air  Pollution,  Water  Treatment, and Residue
Handling cost  centers.  Similarly,  salvage or heal utilization
operations should be put in separate cost centers.
  These cost centers classify the operations by function. The
costs incurred are for labor, parts  and supplies,  utilities, and
overhead, and they must be allocated to the cost centers in
an  accurate  and representative manner  (Diagram II).   Note
that costs are first allocated to all four cost centers/ the Repairs
and Maintenance cost center is then allocated to the three
direct cost centers. The result is the total operating cost for
each direct  cost center.
  There are many alternatives for actually allocating the
operating costs.  A  straight-forward method for  each  type
of expense will be outlined.  Labor costs may be allocated to
the four cost centers  based on the relative number of  hours
employees worked in each area and their  respective wage
rales. Utilities may be allocated  based  on  an engineering
estimate of the relative usage rales of ihe equipmenl in each
cost center.  Bolh  water and  electricity should be allocated.
Parts and supplies will be allocated to each direct cost center
                           75

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                                                       DIAGRAM I

                                              INCINERATOR COST CENTERS
Incomin
Solid waste
Stora
ge pit
                                                                                                                       GASES
                                                                                                                       WATER
                                                                                                                       RESIDU'
                                                             T
                                      f
                        RECEIVING AND
                           STORAGE
                         COST CENTER
  VOLUME
 REDUCTION
COST CENTER
EFFLUENT HANDLING
  AND TREATMENT
   COST CENTER

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                                                     DIAGKAM II

                                               ALLOCATION  OF  COSTS
Building and
improvement
   cost
 Equipment
   cost
                                                                                                                   BSWM (10/69)

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after first being recorded in ihe Repairs and Maintenance cost
center.  General overhead, which includes supervision,  in-
surance, etc.,  can  be allocated equally  lo each  cost center
or on the basis of the relative number of employees in each
cost center. The latter technique  is recommended.  Finally,
the Repairs and Maintenance cost center is allocated  to the
three direct cost centers based on the  actual expenses  in-
curred in each one.
  The sum of the costs of these three direct cost centers is the
total operating cost.  The total annual cost of operations rep-
resents  these operating  costs plus  the costs of financing and
ownership.
  The actual forms are designed  lo facilitate the collection
and later allocation of costs to these cost centers.

                    Forms and Reports
  The reports are most easily grouped into those that are used
lo collect the  data on operations and those used lo reduce
and present the data for the purposes of analysis, decision
making, and control.
  This  data reduction and presentation cannot be accom-
plished  without the  daily recording of all pertinent activity
and cost information.  Data not recorded  daily  are not  re-
trievable at some  later dale.  Incinerator  personnel, super-
visors, and others  involved in  operations primarily use the
following forms (1  through 4) lo record the data  required.
  Weekly Labor Report (Form  1).  Daily entries of labor ac-
tivity are recorded in duplicate at the site. One  copy  is for-
warded  lo  ihe payroll deparlmenl for determining weekly
wages.  The incinerator supervisor and  ihe accounling de-
partment use the other copy for compuling lolal  labor hours
and assigning  ihese hours and associated cosls  lo ihe four
cost centers.
  Daily Truck Record (Form 2).  The wasle received and resi-
due removed, as well as ihe types and  sources of waste  re-
ceived,  are  recorded manually on this  form  for ihe  entire
day. (If  ihe incineralor has a scale thai automatically records
the weight informalion, thai part  of ihe form would be  re-
placed  by  ihe weight lickel or record  of the scale.)   Each
delivery is recorded separately  by  ihe weighmaster.  A
                            78

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                                                                                                                                                      FORM  1
                                                               WEEKLY  LABOR REPORT
           INCINERATOR:



           SIGNATURE: _
                       DATE:



                       SHIFT: .
Employee
ident





-0
vo







Tot
Day 1
Cost
center














X
Hours















Day 2
Cost
center














X
Hours















Day 3
Cost
center














X
Hours















Day 4
Cost
center














X
Hours















DayS
Cost
center














X
Hours















Day 6
Cost
center














X
Hours















Day?
Cost
center














X
Hours















Individual
totals















Comments (Note causes
and hours of absence, etc.)














xxxxxxxxxxxxxxx
   Instructions:  Incinerator supervisor to complete this  form  daily.  List all  em-
ployees  separately including temporary help.  "Hours"  refers to hours worked
daily. At the end of  each week forward one copy to  the payroll  department  and
retain the original for further use.
   Abbreviations of  cost centers and workers to be assigned to each:  R&S  =
receiving and storage:  crane  operator, weightmaster, tipping floor, and charging
attendants.  VR  =  volume reduction:  stokers, control  monitors, etc.  EHT  =
effluent handling: residue haulers, disposal site operators, etc. R& M = repairs and
maintenance: include all general maintenance workers and  part time repairmen.
                                                                                                                                                 BSWM (10/69)

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                                          DAILY TRUCK  RECORD
                                                                                                         FORM 2
INCINERATOR: .
                                                                     DATE:
SIGNATURE: .
                                                                     SHIFT:
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
12
15
16
17
18
19
20
Truck *
identification




















Totals
Time




















X
Wastes
Source




















X
Type*




















X
Weight
in




















X
Weight out
(or tare weight)




















X
Net amount
Wastes





















Residue





















                        Instruction: To be completed  by weighmaster for  each  delivery  of waste or
                     removal of residue.
                      'Truck identification is number of the public truck; if private vehicle, the name
                     of  company for billing purposes.
                      t Source: R  -  residential; C  -  commerical; I    industrial.
                      t Type: R    rubbish; G   garbage (also unusual items).
                                                       80
                                                                                                    BSWM (10/69)

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second weighing of the empty truck  may  be taken or the
vehicle's tare weight (as officially determined  by a licensing
agency, etc.) may be substituted.  The form is forwarded to
the accounting department at the end  of  each month.  In
addition to utilizing recorded weight data to  bill private users
later, the sources and types of waste data  are useful in special
analyses of trends, compositions,  and distributions  of solid
wastes in the community.

  Daily Report on  Incinerator Operations  (Form 3).  When
there is actual downtime and  repairs  are required,  the ex-
penses that will be allocated to the three direct cost centers
are recorded on  the  lower half of the  two-purpose report.
These data  are particularly useful in  analyzing equipment
performance and cost. In addition, data  on  utility usage are
recorded on the form at the end of each  month.
  The lop of the report is used to summarize the daily oper-
ations. The employee and activity data give management
personnel who are not at the site daily, but  who still require
daily feedback on operations, a quick and accurate summary
of the day's activities. The performance  data  are also useful
in assessing daily efficiency. The  report is completed daily,
sent to the main office,  and filed for later use.
  Incinerator Capital Investment Report  (Form 4). This  form
is completed when construction is finished  or when  the cost
system is first implemented.  Only  when improvements or
new equipment  are  either constructed  or  purchased  is  it
updated.  In addition to collecting the data required to cal-
culate depreciation for the period and  allocating it to cost
centers, the form also summarizes  the  bond and interest in-
formation required to compute the total costs  of financing
and ownership.

  For the most part, Forms 1 through 4 are utilized to collect
the data associated with the construction  and operation of an
incinerator. The  cost of accumulating these  data can  only
be justified by its intensive and effective utilization.  This is
accomplished by meaningful data reduction and presenta-
tion.  The data must be presented clearly and quickly to the
personnel who can use it most effectively  for analyses  and
                            81

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                                                                                          FORM 3
                      DAILY REPORT ON INCINERATOR OPERATIONS
  SITE:
                                                                DATE:
                                        PERFORMANCE DATA
                      % Weight reduction ( ^''burned ):
                      Man hours per ton:
                      Tons of residue per trip:
                      Number of injuries:
EMPLOYEE HOURS
Cost center

Receiving
Volume
reduction
Effluent
Repairs
Totals
Shift
1





2





3





4





ACTIVITY DATA

Wastes received
Wastes burned
Left in pit
Residue
Loads




Tons




REPAIRS AND MAINTENANCE DATA
Equipment
description




Cost
center




Cause




Hours
down




Labor
hours




Labor
cost




Parts
cost




External
costs




Total
cost





UTILITY DATA
(Only complete this section at the end of the month)
                                       Electric
                                                                  Gas
                                                                                          Water
Meter reading
                                                82
                                                                                            BSWM (10/69)

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                                                                                        FORM 4
                    INCINERATOR CAPITAL INVESTMENT REPORT
INCINERATOR;
                                                                    DATE:.
Description

Site:
Land
Surveys
Preparation
Roads
Other
Buildings:
Scale house
Pit
Offices
Main building
Stacks
Other
Equipment:
Scales
Crane(s)
Furnace(s)
Air pollution
Water treatment
Residue removal (including vehicles)
Instrumentation and control
Other
Totals
Size, capacity,
amount, etc.























X
Date put
in use























X
Estimated
total life























X
New cost
























Other
comments























X
Yearly
depreciation


X




















^^^mmz
Monthly
depreciation


X





















                                      FINANCING DATA
Bond type

Face value

Premium
or discount

Interest rate

Yearly interest*

Monthly interest

                Instructions: To be completed by supervisor or accounting department. Depreci-
              ation may be straight-line or on an accelerated basis.

              * Interest must account for  net effect of premium or discount on bond sale.


                                             83
BSWM (10/69)

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control.  The following forms (as well as Form 3) are designed
lo fulfill these objectives.
  Incinerator Operations Summary (Form 5). This form sum-
marizes six distinct groups of information about incinerator
operations for a specific period. For control purposes, monthly
reports would be desirable, although less  frequent prepara-
tion would  be  possible.  The  first two  segments  present
activity and  operating cost data  for the total operation.  Costs
are broken down by lype lo aid the cost analysis, and  the
activity  and performance  factors  are designed  to  help
analyze inefficiencies and performance.  The remaining four
sections break the costs into the  four cost centers. Total oper-
ating costs are presented for each  area  as are other factors
that may be useful lo analyze the functional activities. Obvi-
ously, there  are many other factors and costs  that could be
presented. The  ones illustrated, however, are adequate  for
mosl analyses. Nonetheless, modifications or additions should
be  made for facilities  with different operations  and data
requirements.
  This form, designed  for control  purposes, contains only
controllable expenses for which the supervisor can be held
accountable/ capital or financing costs are not included. The
form is prepared by the accounting department from the data
in Forms 1, 2, and 3 and additional data on file concerning
labor rales, insurance, fringe  benefits and charges from other
departments, external expense  billings, elc.  Copies of  the
form are forwarded to both the facility supervisor and lo  his
superior.  Analysis of the form indicates excessive expenses
and aids ihe supervisor in taking corrective aclion.
  Incinerator Total Cost Report (Form 6).  All  the activities
and costs incurred by the incinerator during the period  are
summarized from data in present and pasl Incinerator Opera-
lions  Summaries (Form 5) and  from the  deprecialion and
interest data  available in the Incinerator Capital Investment
Report (Form 4).  Semiannual and annual preparation would
be  sufficient.  Form 6  — Alternate  can  be used if disposal
charges or other lypes of revenues are associated with incin-
erator operations.
                           84

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                                                                            FORM  5
INCINERATOR:
INCINERATOR OPERATIONS  SUMMARY



                      REPORT PERIOD:   from
                                                                      to
ACTIVITY AND PERFORMANCE

Tons incinerated
% Weight reduction
Total labor hours
% Capacity utilized
% Capacity available
% Utilized/% available
Actual amount






-i- % Budget variance






OPERATING COST TOTALS

Total operating cost
Total labor cost
Utilities cost
Parts and supplies
Outside charges
Overhead
Actual amount






± % Budget variance






RECEIVING COSTS

Total operating cost per ton
Labor hours

Actual amount



± % Budget variance



VOLUME REDUCTION COSTS

Total operating cost per ton
Labor hours
Average operating temperature
Actual amount



± % Budget variance



EFFLUENT HANDLING COSTS

Total operating cost per ton
Gallons of water per ton
Tons of residue per load
Actual amount



± % Budget variance



REPAIRS AND MAINTENACE COSTS

Total operating cost
Receiving repair costs
Volume reduction repair costs
Effluent handling repair costs
Actual amounts




± % Budget variance




                                                                           BSWM (10/69)
                                       85

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                                                                                                                          FORM  6
                                            INCINERATOR  TOTAL  COST REPORT
SITE:
                                                                         REPORT PERIOD:
                                                                                           from .
                                                                                                                 to

Data
Tons incinerated
Weight reduction

Total operating cost
Total financing
and ownership cost
Total cost

Operating cost per ton
Financing and ownership,
cost per ton
Total cost per ton


For this period












±% Variance from budget
for this period












Year to date












±% Variance from budget
for year to date











                                   Instructions:  To be completed by accounting department from data  available
                                in "Incinerator Operations Summary" and "Incinerator Capital  Investment Report"
                                when requested or periodically.  Copy sent to city  manager, head of department
                                of public works, or their equivalent.
                                                                                                                                BSWM (10/69)

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SITE:
 INCINERATOR TOTAL COST SUMMARY




	            REPORT PERIOD:   from.
                                                                                            FORM 6 — Alternate
                                                                                               to
Data

Tons of waste incinerated
Percent weight reduction
Total operating cost
Total financing and ownership cost
Total cost
Operating cost per ton
Financing and ownership cost per ton
Total cost per ton
Revenues — other communities
Revenues — private collectors
Revenues — miscellaneous
Total revenues
Total revenues per ton
Net cost (profit)
Net cost (profit) per ton
For this period
















Budget — this period
















Year to date
















Budget — year to date















BSWM 10/69

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              Summary of Information Flow
  Operating dala are  accumulated daily  al the incinerator
site and transmitted periodically to the accounting depart-
ment.  The  accounting department combines these reports
with additional information it accumulates to get total oper-
ating costs.  This summary is then returned to the supervisor
for his own  use. Next, the accounting department combines
the operating cost dala with the depreciation and interest
cost  data (from the Incinerator Capital  Investment Reports)
to compute  total costs for the period.  This  total cost informa-
tion is then  given to the heads of departments of sanitation
and public  works, or their equivalents.

                    System  Utilization
  Only with efficient and intensive utilization of the informa-
tion  generated from the accounting system and forms can
the additional lime, effort, and money required to implemenl
and maintained the system be justified.  The system's inten-
sive  use promotes two major objectives: quality control and
cost control. Reduced costs  must be accomplished without
deteriorating and operating quality.  Similarly, quality is
interrelated  with the costs of  obtaining it.
  All the factors  thai affect the quality and effectiveness of
incinerator operations can be translated into costs.  Amount
of volume reduction, residue characteristics, and the levels
of stack emissions and water  pollution determine the quality
of operations. Cost control does  not call for economizing at
the  expense of quality. On the contrary, once a level  of
acceptable operation has been determined along with the
attendant costs, the cost control system can help the  super-
visor maintain that level of operation.
  Effective cost control requires timely recognition of exces-
sive costs and identification of responsibility for the increased
costs.  Comparing  units costs (cost per ton of waste inciner-
ated)  with both the current  budget and the  corresponding
period last year helps indicate excessive  costs.  The  use  of
unit  cost facilitates the analysis of costs, independent  of
changes in the level of activity. The cost-center breakdowns
help single out the responsible factor or person.  This system

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allows both of ihese critical faclors to be determined; correc-
tive action may then be effectively initialed.
  The Incinerator Total Cost Report (Form 6) can indicate to
the highest level of municipal management,  i.e., the city
manager or the head of the sanitation department, if costs are
excessive. If so,  the supervisor of the particular facility can
be  held responsible to  the  extent that his operating  costs
have increased.  The  supervisor,  in turn, can  analyze the
cause of this cost rise. He may trace  the increased cost to
the type of cost, as well as the cost center, and possibly to
the employee or piece of equipment responsible.  All of the
needed  data are  in  Form 5  (the  Incinerator  Operations
Summary).
                             89

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                                                                            APPENDIX B
Control of Air Pollution Originating
From Federal Installations

 Announcement of Signing of Executive Order
 11282,
 May 26, 1966

   President   Johnson   today   signed   an
 Executive order requiring all Federal agencies
 to  take  steps to  prevent and  control air
 pollution from Federal installations.
   The  order  directs the  heads of all  Federal
 agencies to lead in the administration's efforts
 to  improve the quality  of the Nation's air.
 Today's order is similar to one the President
 issued  last November directing  the  Federal
 Government  to provide effective leadership in
 the battle against water pollution.
   The  air  pollution  Executive  order is the
 result of extensive  consultation with  Federal
 agencies and with industries affected by the
 order. The Department  of Health, Education,
 and Welfare is issuing standards to supplement
 the  order, by setting precise limitations on
 emissions  which will be allowed from  Federal
 buildings and facilities.
   Today's order  requires that plans for  new
 Federal facilities and buildings in the United
 States  include provisions for air pollution
 control measures necessary to comply  with
 the  standards issued by the Department of
 Health, Education,  and Welfare.  In addition,
 the order directs the head of each agency to
 examine existing installations and to  present
 to the Bureau of the Budget, by July 1, 1967,
 an  orderly  schedule for  bringing all  such
 installations up to the required standards.
   In signing  the  order,  the President stated
 that the most difficult  problem encountered
 in  writing the  order was the  lack  of an
 economically    feasible    technology    for
 controlling emissions of sulfur. The  Federal
 Government  has  proposed  spending more
 than  $3  million  in 1967  on  research to
 control sulfur emissions.  This includes $1
 million for designing four sulfur-removal pilot
 plants,  the  construction  of  which  plants
 would  cost  a total  of  $8  million.  The
 President has directed the Secretaries  of the
 Interior and Health, Education, and Welfare
 to explore with the Bureau of the Budget the
 feasibility  of increasing the Federal effort to
 find  a solution   to  the  sulfur  emission
 problem.
  The President said that a major part  of the
 responsibility for  sulfur research  rests with
 the utilities, the coal and oil  industries, and
 other groups which  will  feel  the economic
 efforts   of  more  stringent   air   pollution
 regulations.  He  pointed   out  that   these
 industries had increased their expenditures for
 air pollution research in the past  few years,
 but  stated  that  much  greater  efforts are
 needed.
  The  President emphasized  that, although
 there were great technological and economic
 problems  in the abatement of air pollution,
 the battle for cleaner air remained a major
 objective  of  his  administration,  and an
 essential element in a better environment for
 America.
 NOTE: For  the text of Executive Order 11282, see the
 following item.
Control of Air Pollution Originating
From Federal Installations

 Executive Order 11282. May 26, 1966
  Prevention, Control, and Abatement of Air
        Pollution by Federal Activities

   By virtue of the authority  vested in me as
 President  of  the  United   States  and  in
 furtherance of the purpose and policy of the
 Clean Air Act, as amended (42  U.S.C. 1857),
 it is ordered as follows:
   Section  1.  Policy.  The  heads  of  the
 departments,  agencies, and establishments of
 the Executive Branch of the Government shall
 provide  leadership in the nationwide effort to
 improve the  quality of our  air through the
                                            91

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prevention,  control,  and  abatement  of air
pollution from Federal Government activities
in the United States. In order to achieve these
objectives—
  ( 1)  Emissions  to   the   atmosphere  from
Federal  facilities and  buildings shall not be
permitted if such emissions endanger health
or welfare, and emissions which are likely to
be injurious or hazardous to people, animals,
vegetation, or  property  shall  be minimized.
The procedures established in section 3 of this
Order   shall   be  followed  in  minimizing
pollution    from   existing   facilities   and
buildings.
  (2)  New  Federal  facilities   and  buildings
shall  be  constructed so  as   to   meet the
objectives prescribed by  this  Order and the
standards established pursuant  to section 5 of
this Order.
  (3)  The  Secretary of  Health, Education,
and Welfare shall, in administering the Clean
Air Act, as amended, provide technical advice
and   assistance  to   the  heads   of   other
departments, agencies, and establishments  in
connection    with   their    duties   and
responsibilities under this Order. The head of
each department,  agency, and establishment
shall  establish  appropriate  procedures for
securing advice from, and consulting with, the
Secretary  of Health, Education, and Welfare.
  (4)  The head of each  department, agency,
and  establishment  shall  ensure compliance
with section  107(a)  of the Clean Air Act,  as
amended (42 U.S.C.  1857f(a)),  which declares
it to be the intent of Congress that Federal
departments and agencies shall, to the extent
practicable and consistent with the interests
of the  United States and within  available
appropriations,    cooperate   with   the
Department   of  Health,   Education,  and
Welfare  and  with any air pollution control
agency in preventing  and controlling pollution
of the air.
  Sec. 2. Procedures  for new Federal facilities
and buildings.   A request for funds to defray
the cost of designing and constructing new
facilities and  buildings in  the  United States
shall  be   included   in  the  annual  budget
estimates   of  a  department,  agency,  or
establishment only  if such  request  includes
funds to defray  the  costs of such measures as
may  be necessary  to  assure  that the  new
facility  or building  will  meet the objectives
prescribed  by this Order and the standards
established  pursuant  to  section  5  of  this
Order.  Air  pollution control  needs  shall be
considered in the  initial stages of planning for
each new installation.
  Sec.   3.  Procedures  for  existing  Federal
facilities  and  buildings,  (a)  In  order to
facilitate   budgeting   for   corrective   and
preventive   measures,  the  head   of  each
department,  agency, and establishment shall
provide for  an  examination  of  all  existing
facilities and buildings  under his jurisdiction
in the  United  States and shall  develop and
present to the Director of the Bureau  of the
Budget, by July  1, 1967, a phased and orderly
plan for installing such improvements as may
be needed to prevent air pollution,  or abate
such air pollution as may exist, with respect
to such buildings and  facilities. Subsequent
revisions needed to keep  any such  plan up to
date shall be submitted to the Director of the
Bureau  of the Budget with the annual  report
required by paragraph  (b)  of this  section.
Future  construction  work  at  each  such
facility  and  the  expected future use  of  the
facility  shall be  considered in developing such
a  plan.  Each  such  plan, and any  revision
therein,  shall be  developed  in  consultation
with the Secretary of Health, Education, and
Welfare in order  to ensure that adoption of
the measures proposed thereby will  result in
the prevention or abatement of air pollution
in conformity with  the  objectives prescribed
by  this Order and  the  standards  prescribed
pursuant to section 5 of this Order.
  (b)  The  head  of each department, agency,
and establishment who has  existing  facilities
and  buildings under his jurisdiction  in  the
United  States shall present to  the Director of
the Bureau of the Budget, by July  1, 1968,
and by  the first of each fiscal year thereafter,
                                           92

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an  annual report describing  progress of his
department,   agency,   or   establishment  in
accomplishing   the   objectives  of  its  air
pollution abatement plan.
  Sec. 4. Objectives for Federal facilities and
buildings,   (a)   Except  for   discharges   of
radioactive emissions which are regulated by
the  Atomic  Energy   Commission,  Federal
facilities and  buildings shall conform to the
air pollution standards prescribed by the State
or community in which they  are located. If
State or local standards are not prescribed for
a particular location, or if the State or local
standards  are less stringent than the standards
established  pursuant   to   this  Order,  the
standards  prescribed pursuant to section 5 of
this Order shall be followed.
  (b) The  emission  of   flyash  and  other
particulate  matter  shall  be  kept  to   a
minimum.
  (c) Emission  of  sulfur  oxides  shall  be
minimized to the extent practicable.
  (d) Wherever   appropriate,   tall  chimneys
shall be  installed  in   order  to reduce  the
adverse   effects   of   pollution.   The
determination  of  chimney height  shall  be
based on  air  quality  criteria, land  use, and
meteorological,  topographical, aesthetic, and
operating  factors.
  (e) Solid fuels and ash shall be stored and
handled so as not to release to the atmosphere
dust in  significant quantities.  Gasoline or any
volatile petroleum  distillate or organic liquid
shall be stored  and handled so as not  to
release  to  the atmosphere vapor emissions in
significant quantities.
  (f) In urban  areas  refuse shall  not  be
burned  in open fires and in rural areas it shall
be   disposed  of  in such  a   manner  as  to
reasonably minimize pollution.  Refuse shall
not  be  left in dumps  without being covered
with inert matter  within  a reasonably short
time. Whenever incinerators  are used  they
shall be  of  such  design  as will  minimize
emission of pollutant dusts,  fumes,  or gases.
  (g) Pollutant  dusts,  fumes, or gases (other
than those for which provision is made above)
shall not be discharged to the atmosphere in
quantities  which  will  endanger  health  or
welfare.
  (h)  The  head  of each department, agency,
and establishment shall, with respect to  each
installation in  the United  States under his
jurisdiction, take,  or  cause to be taken,  such
action as  may  be necessary  to  ensure  that
discharges  of radioactive  emissions to  the
atmosphere are in  accord with  the rules,
regulations, or  requirements of the  Atomic
Energy  Commission  and the  policies  and
guidance of the  Federal Radiation Council as
published in the Federal Register..
  (i) In extraordinary cases where it may be
required in the  public interest, the Secretary
of  Health,  Education,  and  Welfare  may
exempt any Federal facility or building from
the objectives of paragraphs (a) through (g) of
this section.

  Sec. 5.  Standards,   (a) The  Secretary of
Health, Education, and Welfare shall prescribe
standards   to  implement   the   objectives
prescribed by  paragraphs (a) through (g) of
section 4  of this  Order.  Such standards may
modify   these   objectives   whenever    the
Secretary  of Health,  Education, and Welfare
shall  determine that such modifications  are
necessary  in the public interest and will not
significantly conflict with the intent of this
Order.  Prior  to issuing any changes in such
standards, the Secretary of Health, Education,
and Welfare  shall consult with  appropriate
Federal   agencies and  shall  publish   the
proposed  changes in  the Federal  Register
thirty days prior to  their issuance. All such
standards prescribed  by the Secretary shall be
published in the Federal Register.

  (b)  The  permits   authorized  by section
107(b) of the Clean Air Act, as amended (42
U.S.C. 1857f(b)),  may be used to carry out
the purposes of this Order as the Secretary of
Health, Education,  and  Welfare  may deem
appropriate.
                                            93

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  Sec.   6.   Prior   Executive   Order
superseded.  Executive Order No.  10779  of
August 20,  1958, is hereby superseded.
                      Lyndon B. Johnson
The White House
  May 26, 1966
 [Filed  with the Office of  the Federal Register, 8:49 a.m.,
 May 27. 1966]
 Title 42—PUBLIC HEALTH
Chapter I—Public Health Service, Department
  of Health, Education, and Welfare

SUBCHAPTER    F - Q U ARANTINE,
  INSPECTION, AND LICENSING

PART 76-PREVENTION, CONTROL, AND
  ABATEMENT  OF   AIR   POLLUTION
  FROM    FEDERAL    GOVERNMENT
  ACTIVITIES:    PERFORMANCE
  STANDARDS  AND  TECHNIQUES  OF
  MEASUREMENT

  Pursuant to section 5  of Executive Order
No.   11282,   the   Secretary   of  Health,
Education,  and Welfare  hereby  amends
Subchapter  F of Title 42, Code of Federal
Regulations,  by adding a  new  Part  76,  as
follows:

Sec.
76.1  Definitions.
76.2 Intent.
76.3 Applicability.
76.4 Combustion of fuel.
76.5 Sulfur oxides.
76.6 Stacks.
76.7 Storage and handling of fuels and ash.
76.8 Disposal of refuse.
76.9 Other pollution producing processes.

  Authority:  The provisions  of this Part 76
issued  under section  5  of Executive Order
11282.
§ 76.1 Definitions.

  As used in this part:
  (a)  "Executive   Order" means  Executive
Order No. 11282.
  (b)  "Nonurban  areas" means all areas other
than urban areas.
  (c)  "Ringelmann   Scale"   means   the
Ringelmann Scale as  published  in  the  U.S.
Bureau of Mines  Information Circular 7715,
  (d)  "Secretary"  means the Secretary  of
Health, Education, and Welfare.
  (e)  "Smoke  Inspection Guide" means the
U.S. Public  Health Service Smoke Inspection
Guide described in Part 75 of this title.
  (0 "Urban  areas"   means   those  areas
classified  as urban in  the latest  available
Federal  census, or as  Standard Metropolitan
Statistical  Areas by the Bureau of the Budget.

§ 76.2 Intent.

  It  is  the intent of these  standards  that
emissions  to the   atmosphere  from  Federal
facilities and buildings shall not be permitted
if such emissions  endanger health or welfare
and  that  emissions which are  likely to  be
injurious or hazardous  to people, animals,
vegetation, or property shall be minimized.

§ 76.3 Applicability.

  (a)  Unless   otherwise   indicated,   the
standards in this part  apply to both new and
existing Federal facilities and buildings. These
standards  are  effective  upon publication in
the  Federal  Register,   except   for  those
facilities  and  buildings  which are  likely to
require  installation of  improvements under
the plan to be submitted in accordance  with
section 3 of the Executive Order.
  (b)  Except  for  discharges of  radioactive
effluents which are regulated by the Atomic
Energy  Commission,  Federal  facilities   and
buildings shall  conform  to the air  pollution
standards   prescribed   by  the   State  or
community in  which they are located. If State
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or local  standards  are  not prescribed  for a
particular location, or  if the State or local
standards are less stringent than the standards
prescribed herein, the standards  in this part
shall be  applicable to  discharges  from  such
Federal  facilities  and  buildings  except  as
otherwise indicated.
  (c) Temporary  operations  that  may  result
in potential air pollution  problems,  such as
those associated with research, development,
test, evaluation, space, and military activities,
shall be conducted with such precautions and
safeguards as are needed to achieve the intent
of these standards,
  (d) The Secretary may, upon application of
the   relevant    department,   agency    or
establishment, exempt any Federal facility or
building  from  the objectives contained  in
section 4 of the Executive order and from any
or  all   of  these  standards whenever he
determines that the activities of such building
or facility will  not significantly conflict with
the intent  of the Executive  order and that
such an exemption is in  the public interest.
 § 76.4 Combustion of fuel.

  (a) The following standards apply to  the
 combustion  units  of facilities  and buildings
 having a heat input of less than 1,000 million
 B,tu,/hour,  other than fireplaces, stoves,  or
 grills burning wood or charcoal:
  (1)  Manually fired equipment shall not  be
 installed  as  new  or  replacement equipment,
 except for the burning of anthracite, coke, or
 smokeless fuel.
  (2)  (i)  For   new   units,  except  during
 startup, cleaning of fires, or soot blowing, the
 density of any emission  to the  atmosphere
 shall not  exceed No.  1 on the Ringelmann
 Scale or the  Smoke Inspection Guide.
  (ii)  For   existing   units,   except  during
 startup, cleaning of fires, or soot blowing, the
 density of any ernission  to the  atmosphere
 shall not  exceed No.  2 on the Ringelmann
 Scale or the  Smoke Inspection Guide.
  (3) A photoelectric  or  other type smoke
detector, recorder, or alarm shall be  installed
on units larger than ten million BTU  per hour
input, except where gas or light oil (No.  2 or
lighter), is burned.
  (4) During routine operation, the  emission
of particles  larger  than 60 microns  shall not
normally occur.
  (5) Means  shall  be  provided  in all  newly
constructed  units and wherever practicable in
existing   units   to   allow   the   periodic
measurement of flyash and other partlculate
matter.
  (6) All new or replacement  spreader stoker
installations   shall  be   of  a  type   that
automatically discharges ashes to  the ash pit
either continuously or in  very frequent small
increments, and flyash  shall be reinjected only
from boiler passes.
  (7)  For  units  of  less  than  10  million
BTU/hour heat  input, the emission  of flyash
and other particulate matter shall not exceed
0.6 pounds  of particulate matter per million
BTU heat input,  as measured by the American
Society of Mechanical Engineers Power Test
Code  No.   27  for  "Determining   Dust
Concentrations  in   a   Gas   Stream,"   or
equivalent test method.
  (8)  For units between 10 million and 1,000
million BTU/hour heat input, the emission of
flyash  and other particulate matter  shall not
exceed that specified in figure 1, as measured
by the test method specified in subparagraph
(7) of this paragraph. Existing units shall  meet
this  standard within  the  time designated by
the plan submitted in accordance with section
3  of the Executive order  except that  with
respect  to existing spreader stoker  units the
plan may  specify  certain  units which  may
emit particulate  matter at an  interim rate not
exceeding 0.6 Ibs/million BTU heat input.
  (b) For units  having a  heat input of more
than   1,000  BTU/hour,  the  appropriate
department, agency,  or  establishment  shall
seek special advice  from the Secretary  with
regard to smoke, flyash, and other particulate
emissions.
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                                        FIGURE I

               MAXIMUM  EMISSION  OF  PARTiCULATE MATTER
                     FROM  FUEL  BURNING INSTALLATIONS
               o.io
                                                   100

                         TOTAL  INPUT—MILLIONS OF BTU PER HOUR
                       ipco
§ 76.5 Sulfur oxides.
  (a) Combustion  units  of  facilities   or
buildings not located  in areas specified by the
Secretary under paragraph (c) of this section
and  whose  heat  input  is  less than  1,000
million BTU/hour shall burn the lowest sulfur
content fuel that is  reasonably available. In
determining   reasonable   availability,   the
factors  to  be  considered  include,  among
others, price, firmness of supply, extent of
existing pollution, and  assurance  of supply
under  adverse  weather  and  natural disaster
conditions.
  (b) For  combustion   units  of  Federal
facilities  or  buildings not located  in areas
specified by the Secretary under paragraph (c)
of this section and whose heat input is more
than 1,000 million BTU/hour, the appropriate
department,  agency, or establishment shall
seek special  advice  from the  Secretary with
regard to sulfur-oxide emissions.
  (c)  (1)  For    Standard   Metropolitan
Statistical Areas  or Standard Consolidated
Areas whose central city  has a population
greater  than 2  million  and  a  population
density   greater  than  15,000  persons  per
square  mile, the Secretary  will,  within  6
months   after  the  effective   date of  the
regulations in this part, establish by regulation
limits on the emission of sulfur oxides to the
atmosphere or prescribe such control steps or
measures as  may be necessary over time to
abate  or  control sulfurous  pollution from
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Federal installations. The limits or measures
so established shall  be no less stringent than
the relevant State or local requirements.
  (2) Such   limits  or   measures  shall  be
established   only  after   consultation  with
appropriate Federal,  State and local officials
and  affected  parties.  Not less than 30 days
prior to prescribing such limits  or  measures,
the  Secretary  will  publish  in  the Federal
Register notice of his  intention to adopt such
limits or measures, and will thereafter publish
in the Federal Register the limits or measures
established. The  Secretary may at any time
designate  other urban areas which suffer from
extremely high air pollution  levels, and after
similar  consultation,  and  publication in  the
Federal  Register,  prescribe  such  limits or
measures  as  he  determines are  necessary to
carry out  the intent of this order.
  (d) The emission of the oxides  of sulfur
the atmosphere shall be monitored  at regular
intervals by determining the sulfur content of
the  fuel used or by  determining the sulfur
content of flue gases.

§ 76.6  Stacks.

  For buildings or facilities in  nonurbanized
areas,  the  particle  emission  standards  of
§ 76.4(a) (7) and (8) may be revised for an
individual  installation by an amount to be
determined by the Secretary, when:
  (a)  The stack height exceeds by  2/4 times
the height of the highest building in that area,
and
  (b) The pollution level in any area will  not
be significantly increased thereby.
For large plants the determination of chimney
height shall be based on air  quality criteria,
land use,  and meteorological, topographical,
aesthetic,  and operating factors.

§ 76.7  Storage and handling  of fuels and ash.

  (a)  Solid fuels  and  ash  shall be stored and
handled so as not to release to the atmosphere
dust in significant quantities.
  (b)  In quantities of 40,000 gallons or more,
gasoline or any volatile petroleum distillate or
organic liquid having a vapor pressure of 1.5
p.s.i.a.   or   greater  under   actual  storage
conditions shall be stored in pressure tanks or
reservoirs or  shall be  stored in  containers
equipped with  a floating  roof  or  vapor
recovery  system  or other  vapor emission
control device.
  (c)  Stationary gasoline storage tanks with a
capacity  of  250 gallons  or  more shall  be
equipped with  either submerged filling inlets
or with  vapor  recovery or emission control
systems  such  that  loss  of  vapor to  the
atmosphere  during filling operations shall be
minimized.
  (d)  Gasoline  or petroleum distillate  tank
car or tank  truck loading facilities handling
20,000 gallons per  day  or  more shall  be
equipped with  submersible   filling arms  or
other vapor emission control systems.

§ 76.8  Disposal of refuse.

  (a)  Refuse shall not be burned in open fires
in urban areas.  In nonurban areas  there shall
not be burned  in open fires, within a 24-hour
period, more than 25 pounds of material at a
single  site nor more than  500 pounds  of
material at  any  number  of sites  within a
1-mile  radius,  except  that  these  quantities
may  be exceeded when  the open burning
occurs at diverse sites such as are associated
with    railroad   rights-of-way,    interurban
highways,    irrigation   canals,   forests,
agricultural  operations,  etc.  Deteriorated or
unused  explosives,  munitions,  and  certain
hazardous materials may be burned in open
fires,    in   accordance   with   recognized
procedures.  Refuse shall not be left in dumps
without being  covered  with  inert  matter
within a reasonably short time.
  (b)  Refuse  shall  be incinerated  only  in
facilities specially designed for  that purpose.
Incinerators shall meet  the emission visibility
standards of § 76.4  (a) (2)  and (a) (3). In
addition, for installations burning 200 pounds
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 of refuse  or  more  per hour, emissions shall
 not exceed 0.2 grain of particulate matter per
 standard cubic foot of dry flue gas corrected
 to 12  percent carbon  dioxide  (without the
 contribution  of auxiliary  fuel), and shall not
 normally  include  particles  larger  than  60
 microns. For  installations  burning fewer than
 200 pounds of refuse per hour, emissions shall
 not exceed 0.3 grain of particulate matter per
 standard cubic foot of dry flue gas corrected
 to 12  percent carbon  dioxide  (without the
 contribution of auxiliary fuel).

 § 76.9  Other pollution producing processes.
   For dusts, fumes, or gases from any process
 not   heretofore   described,    except    for
 discharges of  radioactive effluents regulated
 by the Atomic Energy Commission, whatever
 measures may  be necessary to  comply with
 the  intent  of  these  regulations shall  be      Dated: June 2, 1966.
 applied.   This   will   generally  require   the
 installation   of  equipment  or  devices  to
 minimize such  emissions to the point where
 they  will  meet  the  standards contained in
 these  regulations. For processes  which emit
 toxic  substances in  quantities which  might
   endanger health or welfare and for fires which
   emit smoke  or fumes  at  official fire fighting
   schools, the  appropriate department, agency,
   or establishment shall seek special advice from
   the  Secretary.

     (Note: Tile Department of Health, Education, and Welfare
   will, from time to time, and after consultation with industries
   concerned, issue "Guides of  Good  Practice"  for specific
   operations  to  aid Federal  departments, agencies,  and
   establishments in the selection of equipment and methods for
   meeting the  performance  standards.  For emissions  not
   covered herein,  or for Which there have  been issued no
   applicable  "Guides of  Good Practice," the Department of
   Health, Education, and  Welfare  will provide  technical
   material and  consultation  to departments, agencies,  and
   establishments  requesting such  assistance.  Requests  for
   "Guides  of  Good   Practice,"  technical  material,   or
   consultation  should be  directed either  to  the  Federal
   Facilities  Section,  Abatement Branch, Division  of  Air
   Pollution,  Public Health Service, Department of Health,
   Education, and Welfare, Washington, D.C., 20201, or to the
   appropriate Regional Air  Pollution Program Director of the
   Public Health  Service located in the Department of Health,
   Education, and Welfare Regional Offices.)
                           John W. Gardner,
              Secretary of Health, Education,
                                    and Welfare.
   [F.R. Doc. 66-6201; Filed, June 2, 1966; 12:24 p.m.]
»US GOVERNMENT PRINTING OFFICE: 1973 514-151/1611-3
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