technical-economic study
of
solid waste disposal
needs and practices
-------
This study was financed by a contract with the Bureau of
Solid Waste Management, Environmental Control Administration,
U.S. Department of Health, Education, and Welfare, and the
report has been reproduced as received from the contractor.
No editorial or other changes have been made, although a
new title page and foreword have been added, and the photo-
graphs have been deleted.
Since solid waste management is a relatively new field,
and since the relationships of economics to solid waste
technology are just being explored, the conclusions and
evaluations presented should be considered as preliminaty
in nature. The findings, recommendations, and opinions
in the report are those of the contractor and not necessarily
those of the Government. Neither do they imply any future
Government study, recommendations, or position.
-------
TECHNICAL-ECONOMIC STUDY OF
SOLID WASTE DISPOSAL NEEDS AND PRACTICES
Municipal Inventory (Volume I)
Industrial Inventory (Volume II)
Information System (Volume III)
Technical-Economic Overview (Volume IV)
This report (SW-7c) was written for the Bureau of Solid Waste Management
by Combustion Engineering, Inc., Windsor, Connecticut,
under Contract No. PH 86-66-163
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Consumer Protection and Environmental Health Service
Environmental Control Administration
Bureau of Solid Waste Management
Rockyille, Maryland
1969
-------
PUBLIC HEALTH SERVICE PUBLICATION NO. 1886
-------
FOREWORD
Rising population in the United States, increasing urbanization of
this population, industrial growth, and the unparalleled affluence of Amer-
ican society have resulted in an ever-increasing volume of wastes in the
solid state that must be regularly collected, transported, and ultimately
disposed of. Per capita generation of solid wastes has risen from 2.75
pounds in 1920 to 5.3 pounds in 1968, and this figure may rise to 8 pounds
by 1980. At the very time that these larger amounts of solid wastes must
be managed, cities are faced with shortages of suitable disposal sites,
and with present solid waste management practices that are inadequate to
protect the environment.
The national character of the solid waste problem was recognized in
1965 with passage of the .Solid Waste Disposal Act (PL 89-272). This legis-
lation authorized the Department of Health, Education, and Welfare to: (1)
initiate and accelerate a national research and development program for
new and improved methods of proper and economic solid waste disposal; (2)
provide technical and financial assistance to State and local governments
and interstate agencies in the planning, development and conduct of solid
waste disposal programs.
Upon assuming responsibilities under this Act, the Federal solid
wastes program was confronted with a lack of comprehensive information to
define the solid waste problems of municipalities and industries in
specific terms, and to assess the existing state of solid waste technology.
-------
The present study was performed under contract PH 86-66-163 to supply such
information for the purpose of identifying areas requiring particular atten-
tion, and in order to draw some conclusions concerning the economics of
solid waste management.
Since submission of this report, the Bureau of Solid Waste Management
has completed a National Survey of Community Solid Waste Practices that
provides a statistically reliable estimate of the prevailing costs, modes
of collection, processing and disposal, and the quality of solid waste man-
agement in the United States. Persons interested in obtaining basic infor-
mation in the solid waste field are referred to the National Survey. '+
In cases of statistical discrepancy between the publications, the National
Survey should be considered authoritative.
--RICHARD D. VAUGHAN, Director
Bureau of Solid Waste Management
*Muhich, A. J., A. J. Klee, and P. W. Britton. Preliminary data
analysis; 1968 national survey of community solid waste practices. Public
Health Service Publication No. 1867. Washington, U.S. Government Printing
Office, 1968. 483 p.
+Muhich, A. J., A. J. Klee, and C. R. Hampel. 1968 National survey of
community solid waste practices. Public Health Service Publication No. 1866.
Washington, U.S. Government Printing Office, 1968. (In press.)
-------
municipal inventory
(volume i)
-------
INTRODUCTION TO VOLUME I - MUNICIPAL INVENTORY
The study presented in this volume is part of a four-volume report.
other volumes are:
The
Volume II
Volume III
Volume IV
Industrial Inventory
Information System
Technical-Economic Overview
Volume I has three parts. Part 1, Pictorial Overview, presents photographs
to indicate the scope of solid waste operations.* Part 2, Municipal Inventory,
presents statistical data in order to obtain some dimensions of the solid
waste problem. Part 3, Mathematical Model, presents some mathematical
concepts for predicting solid waste generation and solid waste reduction
requirements.
The material in the report was prepared by Mr. W. Richard Copp and
Mr. Joseph H. Bacher of the Product Diversification Department.
Mr. Elliot D. Ranard served as Program Manager for Combustion Engineering, Inc.;
Mr. Ralph J. Black served as Project Director for the Public Health Service.
For reasons of economy, Part 1 has not been reproduced.
-i-
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PART 2
MUNICIPAL INVENTORY
W. Richard Copp
Senior Product Analyst
Product Diversification Departmer
-------
TABLE OF CONTENTS
Page
I. SUMMARY 1
II. INTRODUCTION 2
III. CONCLUSIONS 3
IV. RECOMMENDATIONS 5
V. METHOD OF APPROACH 6
VI. SOLID WASTE GENERATION 9
VII. SOLID WASTE DISPOSAL 14
VIII. PLANNING GAP 21
IX. CENTRAL CITIES AND SATELLITE TOWNS 25
X. REFERENCES 30
XI. APPENDICES
A. WESTERN UNION QUESTIONNAIRE 31
B. SELECTION OF FIFTY CITIES FOR INTERVIEW 32
C. INTERVIEWERS CHECK LIST OF QUESTIONS 34
D. TRIP REPORT - BALTIMORE, MARYLAND 39
E. TRIP REPORT - HOUSTON, TEXAS 42
F. TRIP REPORT - JERSEY CITY, NEW JERSEY 57
G. TRIP REPORT - NORWALK, CONNECTICUT 62
H. TRIP REPORT - ROME, NEW YORK 67
-i-
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SECTION I
SUMMARY
During the fall of 1966 and the spring of 1967, approximately 600 cities
were surveyed and municipal officials in 50 of these cities were interviewed
in person to define in limited depth the problem areas of municipal refuse
generation, collection and disposal.
From the information obtained in these surveys and interviews, the amount
of refuse generated from residential and commercial sources was determined.
The number of installed incinerators and composting plants in operation in
the United States was also defined. It was further determined that there
is an apparent lack of well kept records on solid waste disposal practices
and an apparent deficiency in adequate planning for solid waste disposal
facilities in the majority of communities.
Mathematical models (equations) were developed to predict the capacity of
installed waste reduction facilities (i.e. incinerators and composting
plants) in 1975 in the United States. In addition, a mathematical model
was developed for the state of Connecticut to predict quantities of com-
mercial, residential and industrial waste production and the requirements
for waste reduction facilities to handle these .waste streams in 1975.
-1-
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SECTION II
INTRODUCTION
The municipal refuse disposal problem is increasing every year because per
capita production of refuse is increasing and vacant land is decreasing.
There is also an increasing interest in the interrelationships -between
waste reduction equipment and air and water pollution, and therefore, solid
waste disposal will ultimately be considered in the context of an overall
waste generation, waste reduction system including air and water pollution
control.
This report reviews municipal solid waste disposal practices with emphasis
on solid waste generation, solid waste reduction equipment and planning
problems.
Part 2 of this report presents statistical data obtained from a survey of
approximately 600 cities and personal interviews of cognizant people in
50 cities. In addition, 5 cities were interviewed in limited depth to
obtain an overview of municipal disposal practices in the central city and
surrounding towns.' Part 2 of this report was prepared by Mr. W. Richard Copp,
Senior Product Analyst of the Product Diversification Department.
Part 3 of this report presents an inventory of solid waste reduction
facilities such as incinerators and composting plants and develops
mathematical models (equations) which can be used by state and county
planners for predicting solid waste production and solid waste reduction
facility requirements. Part 3 of this report was prepared by Mr- Joseph H.
Bacher, Administrative Engineer of the Product Diversification Department.
Mr. George W. Tuite and Mr. Michael L. Daversa of Combustion Engineering's
Corporate Systems Group participated in a consulting capacity.
-2-
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SECTION III
CONCLUSIONS
A. STATISTICAL DATA
1. Approximately 1,380,000,000 pounds of residential, commercial and
industrial wastes are generated each day in the United States.
Approximately one billion pounds of this solid waste must be disposed
in either municipal or private contractor facilities; the remainder
is disposed of in industrial sites.
2. It is estimated that a typical urban area must dispose
approximately 5.5 pounds per capita per day of solid waste from all
sources, and that the "national" figure based on a population of
two hundred million people is 5.1 pounds per capita per day.
3. Approximately 20 percent of communities of over 25,000 population use
incineration to dispose of their solid wastes; the remaining com-
munities use sanitary landfill,, open dumping, open burning or
composting.
4. Approximately 9 percent of municipal refuse is incinerated.
5. As of December 31, 1966, there were 74,600 tons per day of installed
incinerator capacity operating in the United States.
6. As of June 1967, there were approximately 730 tons per day of
installed composting capacity in operation in the United States.
7. Many cities are not faced with long hauling distances to their
current disposal site with approximately one half of the cities
reporting the hauling distance of less than five miles.
8. Approximately 50 percent of the cities over 25,000 population
currently using sanitary landfill have less than six years of life
left in their existing facility and many of these do not know at
this time where the next facility will be located.
B. PLANNING
1. Little or no data is kept by the typical municipality of the physical
make-up of refuse.
2. Significant improvements can be made in the data gathering and record
keeping of most municipalities.
3. There are apparent differences in solid waste problem areas from
one population strata to another and these should be examined
separately.
-3-
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4. If present trends continue and further long range planning is not
expanded, there will be a lack of facilities to handle solid waste
in 1975.
5. Regionalization is recognized to be a practical solution to the
solid waste disposal problem in many areas; however, considerable
political and emotional objections exist to its implementation.
6. A possible short term solution to the facilities gap is expansion of
the private contractor's role because of his ability to cross
municipal and political boundaries. For example, he could use a
private disposal site for the refuse of several communities.
C. MATHEMATICAL MODEL
1. Mathematical models (equations) can be formulated to predict installed
incinerator capacity and solid waste production and these models
can be tied into a "national" series of models for planning
purposes in each of the states. Since any model is based in part
upon historical data, the use of these models as planning tools
must be continuously evaluated over a period of time.
2. Mathematical models can be developed as a function of several
parameters. The best ones are (given for a region such as a town or
county):
a. Population.
b. The ratio of population to the total possible population a town
can have consistent with present zoning and land use.
c. Manufacturing employment.
d. Total possible manufacturing employment.
e. Vacant land.
-4-
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SECTION IV
RECOMMENDATIONS
A. Determine the quantity of solid waste generated in commercial and
institutional establishments, the interaction between the two waste
flows and how these should be projected for a typical urban community.
B. Clearly define the apparent planning deficiency in the majority of
communities and implement programs to assist state and local authorities
in eliminating this deficiency.
C. Investigate ways and means of using the private contractor's ability to
cross political boundaries to hasten the regional approach to solid
waste disposal.
D. Formulate and recommend standard record keeping procedures to insure
uniform reporting of data.
-5-
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SECTION V
METHOD OF APPROACH
In order to obtain data regarding the solid waste disposal problems of
municipalities in the United States, approximately 600 cities were selected
to canvass for information. These cities included two groups. The first
group consisted of cities in the population class of 25,000 to 50,000.
The second group consisted of cities with population of 50,000 or more.
The 1960 census figures were used to determine population. All of the
cities with populations of 50,000 and over were surveyed. All cities in
the 25,000 to 50,000 population range in the following states were surveyed.
California New Jersey
Connecticut New York
Delaware Ohio
Illinois Pennsylvania
Indiana Rhode Island
Maryland Virginia
Massachusetts West Virginia
Michigan Wisconsin
The cities were surveyed in limited depth by using a surveying service of
the Western Union Telegraph Company. The questionnaire used was designed
to survey method of disposal, number of waste reduction plants in operation,
the plant capacity on a twenty-four hour a day basis, the average number of
hours the plant operates each week, the age of the waste reduction facilities,
and the number of waste reduction plants planned for in 1967 and 1968.
Appendix A is an example of the questionnaire that was used.
As a check, fifty cities were selected for personal interview in order to
validate data received by the Western Union survey. They were chosen with
several objectives in mind. The first of these objectives was that the
selection be random in nature. The second objective was that the cities
interviewed cover a broad spectrum of waste reduction facilities and the third
objective was that the cities were chosen in accordance with the size ranges
of from 25,000 to 50,000 and over as outlined in the contract.
Specifically, five cities were chosen in the 50,000 and over population
category because they had sanitary landfill. Five additional cities were
meant to be chosen in this category with composting or mechanical compactor
equipment. It was discovered that only three cities with population of
50,000 and over had composting or compacting equipment. Consequently, the
other two cities, both of whom had composting equipment, were in a size
range below 50,000. Twenty-five cities in this population category were
chosen on a random number basis from those we knew to possess waste reduction
facilities. In the 25,000 to 50,000 population category, five were selected
because we knew they had sanitary landfill and ten with waste reduction
facilities were selected on a random number basis.
-6-
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It was determined from Reference 1 that approximately twenty-seven cities in
the population category of 25,000 to 50,000 (Group A) had waste reduction
facilities. Numbers from one to twenty-seven were assigned to these cities
and a random number table was used to pick the ten eventually interviewed.
Cities with population of 50,000 and over who are known to have solid waste
disposal facilities were divided into five groups or strata.
Group B 50,000 - 100,000 population
Group C 100,000 - 250,000 population
Group D 250,000 - 500,000 population
Group E 500,000 - 1,000,000 population
Group F Over 1,000,000 population
Based on the 1960 census and the data given in Reference 1, there are twenty-
nine cities in Group B which have waste reduction facilities, thirteen
cities in Group C, eight cities in Group D, ten cities in Group E, and four
cities in Group F. It was desired to have five cities included from each of
the five groups. However, there are only four cities in Group F, and,
therefore, all cities in Group F are included. Six cities were then
selected from Group E and five cities from each of the remaining groups
were selected. In all cases, the selections were made by the use of random
number tables. The fifty cities selected are given in Appendix B.
The fifty cities selected were then interviewed by means of a personal visit
and discussions with cognizant people. These interviews were to be of one
day's duration maximum and to deal with data that was readily available in
that time. The objectives of the municipal interviews were to validate
the Western Union data and to obtain where possible the following information.
1. Past and present per capita refuse production.
2. The quantity and characteristics of municipal and industrial waste
handled by the municipality-
3. The amount of waste disposed in sanitary landfill, open dump, or other
methods.
4. General description of waste reduction equipment and operation.
5. Trends in vacant land.
6. Planned increases in waste reduction facilities over the next five years,
7- Comparison of local air pollution control standards and performance of
incinerators.
8. Description of air pollution control equipment.
9. The types of information which would be of interest to the municipality.
-7-
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10. Unit costs for waste reduction equipment such as incinerators, com-
posting plants or other types of equipment presently in use.
11. The present or projected local ordinances which affect air pollution
and water pollution control equipment in incinerators and composting
plants, and solid waste disposal practices in general.
12. The kinds of records of solid waste disposal operation which are kept
by the municipality and what variables are measured.
These objectives were accomplished with the help of the questionnaire
described in Appendix C.
After the fifty cities were interviewed, five of these cities were interviewed
in depth. A team of two people spent about three to five days interviewing
cognizant people in the core city and surrounding towns. The five cities,
Jersey City, New Jersey; Houston, Texas; Baltimore, Maryland; Norwalk,
Connecticut; and Rome, New York were selected because they met most of the
following criteria. The cities:
1. Have adequate records.
2. Have satellite towns.
3, Have both industrial and commercial sources of refuse.
4. Represent each strata.
5. Indicate geographical differences.
6. Have made a recent decision as to a method of waste disposal.
From a review of the fifty city data, it was also decided to determine the
amount of solid waste handled of private contractors, and which is disposed of
in other than municipal facilities in order to obtain a clearer picture of
solid waste generation in urban areas.
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SECTION VI
SOLID WASTE GENERATION
A. RESIDENTIAL AND COMMERCIAL SOLID WASTE
There are four sources of solid waste in urban areas: these are
residential, commercial, institutional, and industrial. These waste
streams are handled by private contractors and municipal collection
services and are deposited in private and municipal disposal facilities.
Some of these wastes are self-disposed such as a hospital incinerating
its pathological wastes. In the industrial sector, the amount of waste
disposed in industrial sites by industry itself and the amount of
industrial waste disposed by others was determined. In the residential
and commercial areas, the amount of self disposal was not determined;
however, it is felt that the residential and commercial figures
presented below which were determined by measurements primarily at the
disposal site give a fair estimate of the residential and commercial
waste generated. In order to get a more accurate picture of the amount
self disposed, a comprehensive study would have to be conducted.
The estimate of solid waste generated in urban areas was obtained in the
following manner.
1. The personal interviews of the fifty cities yielded solid waste
disposed of in municipal facilities and included residential,
commercial, and industrial waste. It was assumed that commercial
waste also included institutional waste.
2. The solid waste obtained in Cl) was reduced by the amount from
industrial sources. In certain cases the industrial waste is broken
out in detailed figures kept by the municipality, and in other cases
it is estimated.
3. The staff of the Refuse Removal Journal was asked to determine the
amount of residential and commercial waste collected by private
contractors and disposed in private facilities. Solid waste collected
by private contractors but disposed in municipal facilities is included
in Q) It was also assumed that the solid waste disposed was equal
to the solid waste generated.
4. An estimate was made of bulky wastes such as refrigerators, furni-
ture, etc.
5. The industrial waste was obtained from the inventory of industrial
waste conducted as part of the overall study and reported in another
volume of this report.
6. It must be remembered that the figures for solid waste generation
were obtained in 1966. Today they may have changed. Even in 1966
another official might have produced slightly different figures.
The fact remains that these figures show the essential proportions
by source involved in the makeup of the generation of solid waste
in the average urban community.
-9-
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The results are shown in Table 1, Only nine cities are shown because
these cities were reported on by the Refuse Removal Journal, and because
the industrial segment could be broken out of the data.
TABLE 1
RESIDENTIAL AND COMMERCIAL SOLID WASTE GENERATION
City
Glendale
Los Angeles
San Francisco
Miami
Baltimore
Cleveland
Philadelphia
Woonsocket
Norfolk
Municipal
3.38
3.36
2.54
3.11
4.18
1.73
2.41
2,58
4.36
vg . 3 . 07
.90
Lbs . /Capita/Day
Data Private Contractor
.83
.06
3.00
.64
.09
.34
.08
.56
.65
.69
Total
4.21
3.42
5.54
3.75
4.27
2.07
2.49
3.14
5.41
3.81
1.19
It can be seen from Table 1 that the residential and commercial figures
range from 2.07 Lbs./Capita/Day to 5.54 Lbs.Capita/Day. This variability
is due to the accuracy of the data reported and -also by virtue of the
fact that some towns have more commercial activity per capita than others.
B. RESIDENTIAL SOLID WASTE
Some municipalities which were interviewed were primarily residential
with negligible commercial and industrial activity. In others, the
residential segment was broken out in the records. These cities were
used to calculate an average residential figure as shown in Table 2.
*a = Standard deviation. There is a 68 percent probability that a city will
fall within the average value plus and minus one a.
-10-
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TABLE 2
RESIDENTIAL SOLID WASTE GENERATION
Lbs.Capita/Day
Niagara Falls, New York
Los Angeles, California
Philadelphia, Pennsylvania
New York City, New York
St. Petersburg, Florida
San Francisco, California
Miami, Florida
Wilton, Connecticut
Weston, Connecticut
Residential Solid Waste
2.70
2.59
2.10
2.42
2.14
3.16
1.75
2.40
2.10
Avg.
a
2.37 Lbs. /Capita/Day
C. BREAKDOWN OF WASTE GENERATION DATA
If we subtract the residential figure of 2.4 Ibs. per capita per day
from the residential plus commercial figure of 3.8 Ibs. per capita per
day, we arrive at a commercial figure of 1,4 Ibs. per capita per day.
It was estimated that bulky combustible and non-combustible refuse amounts
to approximately .3 Ibs. per capita per day.
In addition, data presented in the Industrial Inventory section indicates
that approximately 3.2 Ibs. per capita per day are generated by industry.
This was obtained by dividing the total industrial waste generated by
200 million people. The specific industries covered in this category are
defined in the Industrial Inventory section, but do not include mining
wastes, junked automobiles and solid wastes which are reclaimed and sold
to others. The final breakdown of solid waste generated in a typical urban
area is shown in Table 3.
-11-
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TABLE 3
SOLID WASTE GENERATED IN URBAN AREAS
Lbs./Capita/Day
Residential 2.4
Commercial 1.4
Bulky Waste .3
Subtotal 4.1
Industrial 3.2
Total 7.3
If we wish to arrive at a figure which when multiplied by the total
population in the United States would yield a total solid waste generation
figure for the United States, we would have to reduce the commercial
figure of 1.4 to a lower number because certain non-urban areas do not
generate large amounts of commercial waste. If we multiply the 1.4
figure by the percent urban population of 70%, we arrive at a weighted
figure of approximately 1.0 Ib. per capita per day. The weighted
national figure would then look as shown in Table 4.
TABLE 4
SOLID WASTEt GENERATED IN UNITED STATE_S
Lbs./Capita/Day
Residential 2.4
Commercial 1.0
Bulky Waste .3
Subtotal 3.7
Industrial 3.2
Total 6.9
-12-
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The figures of 6.9 and 7.3 given in Tables 3 and 4 are total generation
figures. It is shown in the Industrial Inventory Study that approximately
55% of the industrial waste is disposed of by the industrial concern in
its own site; the remaining 45% is handled by private contractors and
disposed of in either private or municipal sites. Therefore, the amount
of waste to be disposed of in urban areas in private and municipal sites
would be
7.3 - 3.2 (.55) = 5.5 Lbs./Capita/Day
The corresponding "national" figure is
6.9 - 3.2 (.55) = 5.1 Lbs./Capita/Day
In summary, the total residential, commercial and industrial waste (as
defined in this report) generated per day is approximately:
6.9 x 200,000,000 = 1380 million pounds per day
and approximately
5.1 x 200,000,000 = 1020 million pounds per day
must be disposed of by municipal and private contractor facilities. The
balance is disposed in private industrial sites.
-13-
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SECTION VII
SOLID WASTE DISPOSAL
At present, sanitary landfill is by far the most common method of solid
waste disposal in cities from the size range of 25,000 population and over.
Figure 1 indicates that 190 communities use incineration.
It is shown in Part 2 of this report that there are 75,000 tons/day of
incineration capacity installed at the present time. If we assume an
average utilization of 60% (see Figure 4), and an average solid waste
generation figure of 5.1 pounds/capita/day (see Section VI), the average
percentage of waste incinerated is obtained as follows:
75 x 2 x .60
5.1 x 200 x 100 = 9 percent
The percentage of waste reduced in composting plants is negligible. There-
fore, 81% of this waste is disposed of in landfills.
Care must be exercised in interpreting what is meant by sanitary landfill.
In a large percentage of cases in the fifty city interviews, although called
a sanitary landfill, the area would not be acceptable under the HEW's
accepted definition of the term.
As previously discussed, disposal by landfill plays the most important part
in national solid waste disposal practices. Consequently, it was determined
that the number of years left in existing landfill sites and the distance one
had to haul to these sites would be very significant. Figure 2, based on the
total survey responses, shows that approximately one half of the communities
using landfill have less than six years of life in their current sites and
that they must either find other suitable landfill areas or change their
method of waste disposal. Figure 3 illustrates that while in special cases
long hauls are practical for the disposal of waste in landfill operations,
approximately 50% of the communities haul less than five miles.
In Figures 4S 5 and 6, the cities (from fifty city interviews) have been
classified by strata, with Strata A representing cities between 25,000
and 50,000; Strata B 50,000 to 100,000; Strata C 100,000 to 250,000;
Strata D 250,000 to 500,000; Strata E 500,000 to 1,000,000 and Strata F
over 1,000,000. This was done to see if there was any significance between
the size of the town reporting and the kind of data it reported.
The figures show that there is a difference, with Figure 4 demonstrating
that the smaller towns had more pounds per capita per day of installed
incinerator capacity than did the larger communities, with Strata A showing
7.7 pounds per capita installed and Strata F showing 2.4 pounds per capita
installed.
This does not mean that the larger communities incinerate a smaller
percentage of their refuse. In fact, the reverse is true. The larger the
-14-
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TYPE OF SOLID WASTE DISPOSAL
USED BY MUNICIPALITIES
OF OVER 25,000 POPULATION - 1966
u
LL.
O
Of
UJ
OQ
3
a) Survey
b) Interview
c) Census Data
Total places over
25,000 in 1966
approximately 933
COMPOSTING
INCINERATION
LANDFILL
Some cities have more than one incinerator installed.
There are a total of 250 incinerator plants in the U.S.
Some incinerators handle refuse from several cities. J i
Figurjjf B R A R
Envirofenia! Con'jro! '"dministration
5555 i idgeAve., Cincinnati, u. 45213
-------
YEARS OF LIFE LEFT IN
PRESENT LANDFILL SITE - 1966
Total Response - 397
Source of Data - Survey
200
150
u
a.
O
03
2
13
100
50
0 to 6
6 to 10
YEARS LEFT IN SITE
Over 10
Figure 2
-16-
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MILES TO DISPOSAL SITE - 1966
250
200
150
100
50
SURVEY CITIES
TOTAL 439
INTERVIEW
CITIES -
TOTAL 50
220
90
LJ
u
U_
O
Qi
Ul
co
30
25
20
15
10
31
0-5
12
5-10
Over 10
MILES TO DISPOSAL SITE
Figure 3
-17-
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INSTALLED INCINERATOR CAPACITY
PER CAPITA - BY STRATA - 1966
8
7
>- 6
1 5
E 4
u 3
m 2
1
' ::
7 7-6 SOURCE - 50 Cities
Interviewed
5.
2
3.'
1
2-5 2._4
A B C D E F
STRATA
, PERCENT WASTE INCINERATED - 1966
Figure 4
60
Q SOURCE - 50 Cities 52 5fl
Si! 50 Interviewed |-> ".
| 4° ' 36 36
- 30
£ 1 26
100
90
6?
, 80
0 70
!^ 60
U.
z 50
0
i= 40
^ 30
3 20
10
s ,0 n i9
U 20 i-.
Of
ui
Q.
10
A B C D E F
UTILIZATION FACTOR - 1966 STRATA
SOURCE - 50 Cities Interviewed Figure 5
81
7r6 73 n
56 54
31
"I
"
A B C D E F
STRATA
Fi gure 6
-18-
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community, the larger the proportion of waste which is incinerated. The
percentages shown in Figure 5 were determined from data obtained by personal
interview of cognizant officials. Figure 6 shows that the larger cities
utilize their incinerators to a greater extent than small cities. The
utilization factor is calculated by dividing the number of hours the
incinerator is operated by the total number of hours available in a seven
day week. These high utilization factors are really close to 100% of
available time since a large portion of the time remaining must be used for
repairs and maintenance. Since the actual capacity of an incinerator can be
significantly different from the "name plate" capacity (in this report all
capacities are "name plate" capacities), and since the percent incinerated
is an approximate value, the data shown in Figures 4, 5 and 6 should only
be used to indicate qualitative trends. It should be noted that the data
shown in the figures was obtained from 35 of the 50 cities which had
incinerators.
Figure 7 presents the variation of average age of the incinerator with
strata, and indicates that the larger cities have the oldest incinerators
which may have to be replaced within the next ten year period. In addition,
the larger cities, because they have high utilization factors, will require
new incinerator capacity during this same period.
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20
15
111
o 10
o
AVERAGE AGE OF INCINERATOR
FOR DIFFERENT STRATA - 1966
11
11
13
17
13
C D
STRATA
Figure 7
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SECTION VIII
PLANNING GAP
Figure 8 indicates that a "planning gap" exists. This "planning gap" is
defined as the additional amount of waste disposal facilities required
(over and above that which is planned to be added) to handle the municipal
solid, waste streams. For example, in 1975, the thirty-five cities will
have 42,000 tons per day of installed capacity in operation and approxi-
mately 20,000 tons per day of other capacity such as landfill. However,
this total refuse stream will be 75,000 tons per day leaving a facilities
planning gap of 13,000 tons per day.
The following assumptions were used in Figure 8.
1. The capacity in tons per day of refuse disposal facilities of any kind
will remain constant for the life of that facility.
2. If the population increased between 1950 and 1960, the population will
continue to increase at the same rate.
3. If the population decreased between 1950 and 1960, it will not decrease
further, but will remain at the 1960 level.
4. The municipal refuse per capita was assumed to be 4.1 pounds per day and
to increase at the rate of 2.5% per year. The figure of 2.5% per year
increase was generated by averaging historical data obtained in several
communities which had better than average historical records. A specific
locality's growth rate may vary in some degree from this average figure.
5. Any community planning specific tonnages of increased capacity of any
kind will have them in operation by 1975.
6. Any installation made prior to 1950 will not be in operation by 1975.
7. Any community which indicated a facility to be closed prior to 1975 that
also indicated planning of a future facility would have a sufficient
capacity in that site to deal with the waste disposal requirement in the
year 1975. If a city did not so indicate, it was assumed they would not
have the capacity.
Figure 9 breaks this total picture down into strata. For example, in the
year 1975, with current planning, Strata F will have only 62% of the
total capacity needed; Strata E will only have 75% of the total capacity
needed; only Strata A will have excess capacity.
It is noted that only 28% of the fifty communities have planning bodies to
cope with the solid waste problem; although the data indicates a great
desire on the part of the municipal civil servants to participate in
planning to alleviate this large problem. A further complication already
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80,000
70,000
60,000
50,000
TONS PER DAY
40,000
30,000
20,000
10,000
1960
FACILITIES PLANNING GAP
FOR 35 CITIES - 1966
SOLID WASTE
GENERATED
FACILITIES
PLANNING GAP
INSTALLED
INCINERATOR
CAPACITY
INSTALLED INCINERATOR CAPACITY
SOURCE - 35 of
50 Cities with
Incinerators
1965
1970
1975
YEAR
Figure 8
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FACILITIES PLANNING GAP
FOR 35 CITIES BY STRATA 1966-1975
130 r
120 -
Refuse
Generated-
1975
INCINERATOR CAPACITY
OTHER CAPACITY
TOTAL CAPACITY
Figure 9
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briefly mentioned is that nearly one half of the communities interviewed
indicated that they will not handle any more industrial waste in the future.
Yet, as the country continues to grow, industrial solid waste will grow and
if the municipalities do not arrange for the handling of this material,
industry must dispose of it. The magnitude of this problem will be discussed
in more .detail in the industrial inventory section of this study.
Throughout our interviews it was noted that a considerable awareness of
the problems associated with solid waste disposal existed in the minds of the
civil servants who were directly charged with the responsibilities in this
area. Unfortunately, they also exhibited almost unanimously, a lack of
confidence in the political bodies who were charged with the future planning
and made comments such as "The only time we can get the Council to do
any planning is when the problem is so big that even a blind voter could
see it, and then it is too late".
In fact, we have already noted that a desire exists among civil servants, to
form regional authorities to cope with these problems. Even though this
feeling is expressed, however, in all of the cities interviewed we did not
encounter either a municipality which had participated in a regional
authority and had resigned from it or a municipality currently participating
in an acting regional authority, although some were in the planning stages.
In short, while everybody expresses the belief that regionalization would
help, few, if any, are acting on this belief. There are, of course, certain
notable exceptions, some of which are the Detroit region and Bade and Broward
counties in Florida. The apparent obstacle in regionalization is the fear
on the part of one political entity that it will surrender its authority
to another political entity upon joining a region. For example, a small
town does not want to feel that it will be swallowed by a large core city.
This situation is further complicated by the fact that often the administration
of the "core" city is one political party and the surrounding towns are of
another political party. The natural dislike of having someone else's
garbage in your town is, therefore, compounded by the political difference
of the communities involved.
The very structure and traditions of the state's governmental organization
may further hinder regionalization, particularly in those states such as the
New England states where strong town governments exist at the expense of
relatively weak county or larger regional organizations.
If the political facts of life do not allow for local regional planning,
other alternatives may have to be sought. One of them could be state or
federal regional planning bodies. Another solution might be private con-
tractors who would, in effect, operate on a regional basis with the aid of
state or federal planning bodies.
While the regionalization and planning picture is not as bright as it could
be, continuing work is going on in the hope of improving all aspects of
solid waste collection and disposal. Much of this work is sponsored by the
Public Health Service and a substantial portion is being carried on by
private industry with private funds.
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SECTION IX
CENTRAL CITIES AND SATELLITE TOWNS
The following cities were interviewed in depth:
Baltimore, Maryland
Houston, Texas
Jersey City, New Jersey
Norwalk, Connecticut
Rome, New York
These cities have adequate records, incinerators (Baltimore, Houston,
Jersey City and Norwalk), composting plants (Houston), landfill (Rome) and
have various amounts of cross-flow between the central or core city to the
satellite towns.
The trip reports which are presented in Appendices D5 E, F, G, and H give a
comprehensive view of the wide spectrum of solid waste problems facing the
nation, and the various ways in which communities are solving them.
A summary of the five in-depth studies is presented in the following sections.
A. ORGANIZATION FOR DECISION
In all of the communities interviewed (with one minor variation) the
political organization for decision regarding solid waste problems was
similar. Essentially, the political organization consisted of an
elected official commonly called the Mayor and a body of elected repre-
sentatives called a Council, Board of Aldermen or Board of Supervisors.
Decisions as to changes, additions, expansion or contraction of solid waste
disposal facilities had to be made by common agreement between the Mayor
and supporting elected body. In practical application, it was determined
that the individual in charge of solid waste (sometimes called Commissioner
of Sanitation or Public Works) analyzed the specific municipality's
needs and made recommendations to the Mayor based on engineering analyses.
The Mayor then requested the funds as needed after modification of the
engineering plans to conform to the political climate and pressures of
the time. The elected body of city fathers then further modified the
request, in so far as it was possible, to conform to the special interests
of their constituents.
In one case, a third body, called the Board of Estimates, also reviewed
request for expenditure of this nature. In another case, an "incinerator
authority" was set up as a separate entity.
RECORDING OF DATA - MUNICIPALITIES
The degree of availability of recorded data was different from community
to community. In those communities where there as yet was not a real
problem in terms of unavailable land or high expense, records were often
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non-existent, at the worst consisting of the estimate of the man in
charge of the disposal site as to quantity per week and at the best
consisting of a daily weight of material processed through the waste
reduction facility. Historical records were even more difficult to come
by in the smaller communities, again reflecting a lack of interest or need
of this type of data in the community at the present time. In general,
the larger the community, the more sophisticated the records. Even in
the best case, however, it was frankly admitted that some of the records
would be inaccurate for several reas'ons including political favor for
certain contractors using the facility to lack of attention to record
keeping on anything other than a sampling basis. The best records were
kept by those communities who charged for the use of their facility and
had the most severe solid waste problems.
C. RECORDING OF DATA - INDUSTRY
It was found that industry was well informed in the main concerning its
solid waste practices. In most cases, industry has to hire solid waste
disposal contractors and this item of expense is large enough so that
attention is paid to quantities of waste and historical trends. This
does not mean that this information was always available. In some
instances, industries were uncommunicative because of their fear of costly
regulation or competitive knowledge that might be revealed by their
waste figures.
The accuracy of the records, when the records were furnished, sometimes
depended on the ability of the man in charge to estimate volume or
weight of solid waste accumulations. However, in the larger industries,
reasonably accurate records were found again because of the expense con-
nected with the solid waste disposal problem.
D. RECORDING OF DATA - PRIVATE CONTRACTOR
These were by far the most difficult records to obtain. The private
contracting business is very competitive and private contractors were
hesitant to release information as to their volume of business because
they felt their competitors would gain valuable commercial knowledge.
Those contractors who were willing to talk were often hazy in their record
keeping because of little need to have this information for their day-to-
day business. The staff of the "Refuse Removal Journal" has been active
in helping obtain the best figures available.
E. PERFORMANCE OF FACILITIES - SANITARY LAND FILL
Only one community had sanitary landfill operations that would probably
meet the standards proposed by the Department of Health, Education and
Welfare. In most cases, the landfill was far from sanitary. Very
often open burning was taking place in these sites and in all cases,
loose trash was free to blow about the area. There would be no problem
for insects and rodents to thrive in any of these areas. In the one
community which has a good procedure for sanitary landfill, other
facilities exist which are not run properly some municipally operated
and some privately operated.
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F. PERFORMANCE OF FACILITIES - INCINERATION
In those communities using incineration, reduction of volume of solid
waste disposed of in this fashion is acceptable. The burn-out of the ash,
however, varies from very good to very poor. In the former case, a
clean ash is observed with minute amounts of unburned material noted.
In the latter case, whole sheets of newspapers, orange peels, etc. were
noted in the incinerator residue in an unburned condition..
None of the incinerators had the more sophisticated air pollution devices
and in one community during a temperature inversion, it was noted that
an area surrounding the incinerator within a four mile radius was hazy
with incinerator smoke and smelled of partially burned trash. Only one
incinerator was cleaning its quench water of all putrescible matter by
virtue of pumping this water to a nearby sewage plant for normal sewage
treatment. The other incinerators were discharging their quench water
directly, or after lagooning, to a stream and there is a possibility
that some putrescible matter is finding its way into these streams.
G. ROLES OF THE MUNICIPALITY AND PRIVATE CONTRACTOR
In general, the municipal facilities for waste disposal are reserved
for residential solid waste. However, some municipalities, either for
a fee or free, process both commercial and industrial solid waste.
In most communities, however, the commercial and industrial sources of
solid waste must find other means of disposal.
A few industries chose to dispose of their waste on their own land or
with their own waste reduction equipment. A large number, however, use
the alternative of contracting with a private concern to remove the
waste from their premises. These private contractors in many communities
also service some residences. Many of the private contractors use
private dump sites. Others use the municipal facility. If use of the
municipal facility is permitted, the private contractor chooses the most
economic disposal method.
In general, both the civil servants involved in the solid waste operations
and the private contractors are knowledgeable, concerned people who are
able to discuss intelligently their operations and problems. In fact, it
can be said that in most cases, the private contractor is performing a
service to the community without which the community would be unable to
function. This is particularly true in the larger communities where land
is at a premium. Very often the private contractor removes significant
amounts of solid waste to areas outside the community. In this case,
the private contractor is able to cross political boundaries while the
core city itself would have difficulty in so doing.
H. CROSS-FLOW OF WASTE BETWEEN COMMUNITIES
The smaller communities apparently have little cross-flow of solid waste.
What little there is is generally outward from the core city into the
surrounding and more sparsely settled satellite towns. This is generally
borne by private contracting vehicles. In the larger communities,
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however, the cross-flow of solid waste is either incinerated residue or
unprocessed refuse. Direction of flow is universally out from the core
city which has the most problems in terms of available land and in the
main is carried by the private contractor because of his ability to cross
political boundaries. Character of the waste is generally industrial
and commercial primarily as most communities have some way to take care
of the household waste generated by the taxpayers within their own
boundaries. In several of the larger cities, however, this latter
case is not necessarily a situation which will continue to exist as
available land for non-combustibles and incinerator residue is fast
being depleted.
I. INDUSTRIAL WASTE STREAM
The industrial waste stream is discussed in another section of this
report. It is enough to say here that significant quantities of
industrial waste exist in any industrialized community. Generally
speaking, industry is willing to discuss this problem and has reasonably
good records. Those industries which refuse to discuss the problem
either were sensitive because of competitive information which might
leak out by virtue of competitors knowing their solid waste stream or
were afraid of expensive equipment necessitated by regulatory action
similar to what is being encountered in the field of air and water
pollution control.
J. UNOBTAINABLE INFORMATION
Under the sub-title "Recording of Data" we have discussed certain
inaccuracies which may exist in the records which would contribute to the
inaccuracy of any figures generated in this report. In addition, there
are other gaps in the information which the scope of this contract does
not permit us to fill. In spite of the best efforts of research, the
role of private contractors is not completely defined. This is particularly
true with regard to total tonnage collected and the breakdown of that
tonnage into residential, commercial and industrial sources. In addition,
there is lack of information about self-disposal which in many communities
is significant. Other waste streams such as automobile hulks were beyond
the scope of the contract. In addition, in the case where a community
had an incinerator, bulky non-combustibles often went directly to the
residue site in undetermined tonnage.
K. PLANNING
The preceding discussion would indicate that planning is neededs yet
little is being done on a metropolitan area basis at the moment.
Individual communities from time to time are encountered which have made
an attempt to plan for the future, but little effective regional planning
has been encountered.
In one area, the core city expects to run out of available land for
residue in about five years. One satellite community is spending
thousands of dollars per year in tolls to transport wastes and a neighboring
community with thousands of acres of available land cannot be interested
in joining a joint effort to attack the problem.
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Many reasons are given for this, but it can be speculated that the under-
lying difficulty rests in fear of political dominance by the large
core city and the emotional reaction against someone else's garbage in
the local community.
One large community has had significant strides in the planning area
forced on them by a crisis situation of their existing facilities. The
plans are sophisticated and detailed, but again are not regional in scope.
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SECTION X
REFERENCES
1. Stephenson, J. W. and A. S. Cafiero. Municipal Incinerator Design
Practices and Trends. Proceedings of 1966 National Incinerator
Conference. May 1966.
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SECTION XI
APPENDIX A
WESTERN UNION QUESTIONNAIRE
1. What method is now used for the disposal of your municipal refuse at
the present time?
a. Open dumping e. Incineration
b. Open burning f. Feed garbage to hogs
c. Sanitary landfill g. Other (state)
d. Composting
2. If you dispose of the refuse by open dumping, open burning or sanitary
landfill, what is the hauling distance from the center of the city to
the disposal site?
miles
3. How long will you be able to use the present site?
years
4. Jf you dispose of the refuse by either incineration or composting, what
is the total capacity of your facility on a 24 hour/day basis?
tons per 24 hour day
5. What percent of your refuse do you incinerate or compost?
6. When was your incinerator or composting plant installed?
_ year
7. How many hours per week is each incinerator operated?
_ hours per week
8. How many incinerators or composting plants, and of what size do you
intend to install in the next two years?
Size _ _ tons per day
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SECTION XI
APPENDIX B
SELECTION OF FIFTY CITIES FOR INTERVIEW
The primary objective was to select cities at random with waste reduction
facilities. It was also desired to visit some cities with landfill, com-
posting and mechanical compaction operations. The total number of cities
surveyed was divided into strata according to population size as follows:
Strata A 25,000 - 50,000 population
Strata B 50,000 - 100,000 population
Strata C 100,000 - 250,000 population
Strata D 250,000 - 500,000 population
Strata E 500,000 - 1,000,000 population
Strata F Over 1,000,000 population
From each strata, cities were selected for personal interview. For example,
it was determined that we would visit fifteen cities in population Strata A.
Five of the fifteen were chosen because they had landfill and composting
operations. The remaining ten were chosen from the twenty-seven cities in
the size range which the incinerator plant summary, given in Reference 1,
indicated had incinerators. The sample was obtained by numbering the cities
from one to twenty-seven in order as they appeared in the incinerator plant
summary and selecting the ten by using a table of random numbers from that
group.
Because of shifts in population from 1960, it was eventually determined that
a total of sixteen cities fell in population Strata A. The following list
of cities is segregated by population strata. Those cities which do not have
an asterisk were chosen specifically to visit landfill and composting
operations. Those cities with an asterisk were chosen by the random number
method from the "ASME Proceedings of the 1966 Incinerator Conference" as
described in the example above. The three cities with a double asterisk,
enumerated in population Strata A, were chosen because they had either
composting equipment and fell below the population strata of 25,000 or in
the case of North Tonawanda, New York because it had a mechanical compactor
and was in the 25,000 to 50,000 population range.
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STRATA A:
Burlingame, California
** San Fernando, California
* Middletown, Connecticut
* Stratford, Connecticut
* West Haven, Connecticut
* Clearwater, Florida
** Largo, Florida
Highland Park, Illinois
* Bloomington, Indiana
STRATA B:
Norwalk, Connecticut
Pittsfield, Massachusetts
Rome, New York
STRATA C:
* Glendale, California
* Bridgeport, Connecticut
St. Petersburg, Florida
STRATA D:
* Miami, Florida
* Atlanta, Georgia
* Framingham, Massachusetts
Mount Clemens, Michigan
Clarksdale, Mississippi
Farmington, New Mexico
* Hempstead, New York
** North Tonawanda, New York
* South -Euclid, Ohio
* Abington, Pennsylvania
* Woonsocket, Rhode Island
* Euclid, Ohio
Altoona, Pennsylvania
* Alexandria, Virginia
* Charleston, West Virginia
Camden, New Jersey
* Niagara Falls, New York
* Youngs town, Ohio
* Portsmouth, Virginia
* Indianapolis, Indiana
* Jersey City, New Jersey
* Norfolk, Virginia
STRATA E:
San Francisco, California
* Boston, Massachusetts
* Baltimore, Maryland
* Buffalo, New York
* Cleveland, Ohio
Pittsburgh, Pennsylvania
* Houston, Texas
Seattle, Washington
* Milwaukee, Wisconsin
STRATA F:
* Los Angeles, California
* Chicago, Illinois
* New York, New York
* Philadelphia, Pennsylvania
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SECTION XI
APPENDIX C
H.E.W. INTERVIEWERS
CHECK LIST OF QUESTIONS
* Questions will not be answered at the interview, but will be researched
and recorded with interview information.
A. Western Union Survey - Validating Questions
1. What method is now used for the disposal of your municipal refuse
at the present time? Check one:
a. Open dumping e. Incineration
b. Open burning f. Feed garbage to hogs
c. Sanitary landfill g. Other (state)
d. Composting
2. If you dispose of the refuse by open dumping, open burning or
sanitary landfill, what is the hauling distance from the center of
the city to the disposal site?
miles
3. How long will you be able to use the present site?
years
4. If you dispose of the refuse by either incineration or composting,
what is the total capacity of your facility on a 24 hour/day basis?
tons per 24 hour day
5. What percent of your refuse do you incinerate or compost?
6. When was your incinerator or composting plant installed?
_ year
7. How many hours per week is each incinerator operated?
_ hours per week
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8. How many incinerators or composting plants, and of what size do
you intend to install in the next two years?
Size
tons per day
B. Mathematical Model Data Questions
1. Please complete the following table using date intervals as
available from records kept by the community.
Dates
Tons per day in waste
reduction facility
Tons per day in other
disposal facilities
19
19
19
19
2. What percent of the total waste per day is municipal?
industrial? %
3. What are the industrial wastes?
* 4. Population
Year
Population
Is it more difficult to find vacant land for location of waste
disposal facilities?
Has the vacant land accessible to your community been materially
reduced in recent years?
7. Will it be reduced in the next five years?
8. Would you please locate your facilities on this local map?
* 9. What figures are available concerning increase in w*alth of the
community?
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10. Do you think your municipal facilities will handle more or less
industrial waste in the future?
11. Do you have plans for joining with other communities to jointly
solve your solid waste disposal problems?
12. Request a map showing collection or hauling routes with respect
to location of waste reduction or disposal facilities.
C. Technological - Economic Study Questions
1. What are the operating costs of your facility?
2. What factors do you include in operating costs:
Labor
Depreciation
Utilities
Overhead
Other
3. What improvements to your present installation are desired (required)
to meet pollution standards i.e., scrubbers, precipitators, etc.?
4. What improvements to your present installation to lower operating
costs are desired?
5. What operating standards would you want a new facility to meet
with regard to pollution standards? Operating costs?
6. What was the installed date and cost of your facility?
7. Who was the design engineer of the facility?
8. Which manufacturers produced the components of the facility?
D. Sampling System Questions
1. Does your community, county or state have a solid waste planning
commission? Do you currently plan to join any community to help
with your mutual problems?
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2. If a regional service of some kind were established to assist your
community in planning, would you use it?
3. If you would use it, what kind of information would you like to
receive? i.e., trends, kinds of refuse produced, change in type of
refuse, projections when new facility needed, etc.
4. Would you be willing to submit periodic reports to the regional
service and allow periodic visits by its survey teams?
5. If the regional service made recommendations for changes in your
operations, would you follow them?
6. Would you be willing to participate in a pilot program of this nature?
7. What type of information do you have available on the different
classes of refuse collected?
8. Does the classification vary depending on the area from which it
is collected?
9. Is the information based on observation or do you actually sort the
refuse and sample it? What equipment do you use for sampling?
E. Questions to Aid in Selecting Ten Metropolitan Areas
1. What type of records do you keep pertaining to your solid waste
operations? e.g., tons per day handled, operating costs, number
of complaints received, change in make-up of refuse, etc.
2. Have any studies been conducted of your communities and/or
surrounding regions?
3. Do you have knowledge of industrial and municipal interaction of
solid waste streams and facilities?
4. What information do you have on the significance of apartment
house refuse to your total solid waste stream?
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5. What is the average number of men employed full time in your
collection, waste reduction, and/or landfill operation?
men
F. Questions to Combine with the Above to Further Point Out Areas for
Beneficial Research
1. When your present facilities are exhausted, how far will it be to
the next site?
2. Are your present facility's surroundings industrial, commercial,
or residential?
3. What acreage is allotted to your facility?
4. Do you have an abandoned solid waste facility?
5. If so, when was it abandoned, and why?
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SECTION XI
APPENDIX D
BALTIMORE, MARYLAND
The metropolitan area of Baltimore was analyzed by personal interviews of
cognizant people in the core city of Baltimore. A large private contractor
in the area who operates in all three Governmental units was also inter-
viewed. In addition, ten industries were contacted with varying degrees
of success. The data obtained was analyzed to determine interaction of
waste streams between the communities, and the amount per capita con-
tributed by each segment of the metropolitan area such as residential,
commercial and industrial sources. Historical trends were noted insofar
as historical data was obtainable.
A. DISCUSSION OF THE DATA
It was determined that there is a significant flow of solid waste from
the core city into the satellite communities and counties. This flow
of waste is primarily commercial and industrial material which is
handled by private contractors and deposited in private land fills
outside of the core city boundaries. The figures for 1965 show approxi-
mately 2.4 pounds per capita of material flowing out from the core city
to the surrounding areas. This figure has been increasing materially
as the industrial development of the area continues. The residential
solid waste is 2.8 pounds per capita per day, plus .4 pounds of bulky
refuse. In 1960 the residential figure was 2.2 pounds per person per
day. Baltimore city operates two incinerators, the old one which was
constructed in 1933 has a capacity of 600 tons per day. This incinerator
operates approximately 93% of the time available in a week, as does the
new incinerator. The operating cost is $3.75 per ton, but this figure
only includes its labor, utilities, etc., and does not include
amortization, replacement reserves, or anything of that nature. The
new incinerator was built in 1955 at a cost of $2,193,000. It has a
capacity of 800 tons per day and an operating cost of $3.60 per ton.
The primary reason for the city of Baltimore choosing incineration as
a method of solid waste disposal was a lack of economical land. While
there is still considerable vacant land in the Baltimore city area,
there is simply no economically usable land available. The price per
acre is very high, and the zoning restrictions are very tight for both
residential and industrial land. Most of the available land is used
for residential and commercial buildings.
There is very little self-disposal in the city of Baltimore. High-rise
apartment buildings, however, do have incinerators. Approximately
35% operate in this fashion, the balance of the apartment houses use
private contractors to collect the solid waste.
Water quenching is used for the ash, but it goes to the regular sewer
and is treated as sewage would be treated and consequently, probably
does not pollute surrounding natural waters.
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Currently, the Baltimore city operation has a landfill within its
boundaries where it takes non-combustible solid waste and incinerator
residue. There is a maximum of five years left in this site at present
rates of usage. Should the tempo of solid waste generation increase,
the time left in the site will be reduced.
Adjoining Baltimore city to the north is Baltimore County, a completely
separate Governmental body. Baltimore County is producing 3.1 pounds
per capita per day of which 2.2 pounds per capita are residential solid
waste. Another .7 pounds of commercial waste brings the value to 2.9
pounds per capita. Baltimore County used sanitary landfill as a
method of solid waste disposal. It is currently operating three sites.
At this time, no commercial or industrial material is permitted in the
Baltimore County site. While there are literally thousands of acres
available for land fill operation, the expense of land makes incineration
very attractive to the sanitation officials, and they are seriously
considering incineration at this time. The expense of the land today
is $6,800 to $10,000 an acre for residential land, and as high as
$2,500 per acre for swamp land.
At present, the Baltimore County authorities have closed one of their
landfills because of capacity difficulties. They have been operating
for the last several years by trucking the material through the harbor
tunnel at a cost of $90,000 per year in tolls alone, and yet this
operation is more economical than developing another landfill site
with the cost of land and expense of condemnation proceedings, court
fights, etc.
Twenty-five percent of the homes in Baltimore County probably use garbage
disposal grinders. In addition, there is some private dumping by the
more rural population. The Baltimore County authorities are very
interested in a regional authority which would build new incinerators
and make use of existing land for residue and non-combustible disposal.
The authorities hope to combine with the authorities in Baltimore city
and Anne Arundel County. The satellite area of Anne Arundel County
excluding Annapolis, which has its own organization, is one of the
fastest growing counties in the country. Currently, 55,000 homes are
serviced by private contractors who receive their contracts from the
county authorities. Another 15,000 homes are rural in nature and
dispose of solid waste on their own property in their own fashion. The
entire residential and industrial and commercial solid waste of the
Anne Arundel County goes to private landfill. There is no municipal
landfill at this time. Incineration or even county-operated landfill
is not attractive to the Anne Arundel authorities at this time because
they are purchasing private contractor service for their citizens at
the rate of 15c per pick-up.
Throughout the county exists vacant land in the amount of approximately
100,000 acres. This land at this time is mostly unzoned and varies
from swamp and ravine type to prime building land. The vacant land
throughout the county is increasing in value rapidly because of the
county's growth. The present calculated pounds per capita generation
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of residences is 1.8 pounds per day. No heavy industry currently
appears in Anne Arundel County, but community authorities are making
serious efforts to attract more industry and more residents to their
county.
In addition, at this time, neither Baltimore city, Baltimore County
nor Anne Arundel County permit commercial or industrial solid waste in
municipally operated disposal sites, either incinerators or landfills.
The private contractor, therefore, must have a private disposal site or
this material will have no place to go. At the present time, it is
felt that approximately 1,200 to 2,000 tons per day of commercial and
industrial waste is collected by private contractors in the Baltimore
area, from Baltimore city, Baltimore County and Anne Arundel County.
From 800 to 1,200 tons are collected from Baltimore city and from 200 to
400 tons are collected from each of the counties.
A survey of industrial sources shows a varying degree of industries
awareness and willingness to talk about the problems. It was noted
that some companies had their own incinerators, some their own landfill
sites and some open burning. Most of the plants (except for those
located close to the center of the city) have sufficient land to engage
in some self-disposal practices. In general, the companies did not
keep any records as to amount of refuse being generated. If they did
their own hauling, they usually knew how many truck loads a day were
hauled away. However they did not know the capacity of the trucks or
the amount of refuse in the trucks. If a private contractor did the
hauling, they usually knew the size of their collection containers and
how often they were emptied, but had no idea of the density of the
material. A branch plant of a large corporation whose corporate
management had purchased patent rights to a commercial incinerator and
were currently evaluating it for possible installation at all their
plants was best informed. Despite the opportunity for self-disposal,
private contractors were used extensively by industry. These contractors
carried waste beyond Baltimore city limits estimated at 1.2 pounds per
capita per day.
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SECTION XI
APPENDIX E
HOUSTON, TEXAS
A. GENERAL AND ECONOMIC DESCRIPTION OF THE STUDY AREA
The study area comprises Harris County, Texas which is Standard
Metropolitan Statistical Area Number 078, Houston, Texas. The
County ranks twelfth in the nation in population and the central city,
Houston, containing a very high percentage of the County's population
and economic activity ranks seventh among cities in the nation in
population. Physiographically, the County is in the Gulf Coastal
Plain characterized by very low topographical relief. The drainage
is in rather sluggish incised streams, regionally called bayous.
The major one is Buffalo Bayou, comprising the landward portion of the
Houston Ship Channel which reaches fifty miles from the center of
Houston to the Gulf of Mexico. This channel is lined with heavy industry,
particularly chemical, petroleum and petrochemical, comprising one of
the most highly industrialized areas in the nation. Despite the
industrial activity in the satellite communities along the Ship Channel,
the economic activity of the County in terms of number of establishments
is largely concentrated in the city of Houston.
The climate is mild and rather humid, precipitation being about 46 inches,
the January average temperature about 54° and July average temperature
about 84°. The city has an average annual heating degree days below
65°F. of 1,278.
Despite the high concentration of industry, Harris County has over 60%
of its area in farms. This is a characteristic of the "oasis economy"
of the West and bears upon the solid waste problem. There are no
counties in New Jersey, Connecticut or Massachusetts having 60% of
their land in farms, and to reach such percentages in New York, one must
look to the counties considered rural such as Cayuga, Chautauqua,
Chenango, Cortland, etc. The value of farm land and buildings per acre,
however, is of the same order as that in the states of New Jersey and
Massachusetts.
The county is characterized by a very high growth rate. Among all
urbanized areas having 1960 populations in excess of one million,
Harris County had the highest 1950 - 1960 increase, 62.7%. Los Angeles
was second with 62.3% (but Los Angeles of course has a population of
6-7 million). In addition to the core city of Houston, Harris County
has 109 satellite communities.
Table 1 shows the distribution of these entities by population. Each of
the communities constitutes a potential solid waste generating entity
with a potential or real requirement for collection3 disposition and
disposal services.
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TABLE 1
DISTRIBUTION OF COMMUNITIES IN HARRIS COUNTY
Population
<100
100 - 300
300 - 1,000
1,000 - 3,000
3,000 - 10,000
10,000 - 30,000
30,000 - 100,000
938,219 (Houston)
No. of Communities
32
22
18
20
11
4
1
1
Total 109
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B. THE SOLID WASTE COLLECTION SYSTEM IN HARRIS COUNTY
Harris County has all of the waste generating elements residential,
commercial (including apartment buildings and institutions), industrial
(including mining and manufacturing), construction and agricultural.
While collection itself is not within the scope of the present study,
collection is a major element in disposition and may be taken as a
convenient starting point.
The major single collection and disposition agency is, of course, the
city of Houston. The city has an extensive collection system, from
some 388,000 establishments, using 16 yard packers which average about
four tons per load and operate six days per week. However, as in
most cities, the municipal collection system does not handle all the
solid waste. Wastes of certain types, e.g., industrial, are not
collected by the municipal pick-up nor is waste generated in large
quantities (greater than 2-30 gallon containers per collection) as
from commercial establishments. These are served by the contract
disposition agencies, of which there are several hundred serving the
city itself, plus probably many more serving the county outside of the
city. In 1966 there were issued 614 licenses to contract disposition
agencies for dumping at the Holmes Road facility. About 300 of these
are full time "professionals" and the remainder are part time one truck
operations. About a dozen of these constitute "majors". In a few
areas of the city, the municipality contracts with these agents for
collection and disposition of the waste which is conventionally the
municipality's responsibility in the city as a whole, namely the
residential waste subject to municipal pick-up. The municipality does
this because it finds it cheaper in these areas than in maintaining
its own collection system.
In addition, Houston has an unusual arrangement for supplementing
municipal collection by a device termed "sponsorships". The city pro-
vides only curb-side pick-up, but in certain areas the residents may
wish to have door pick-up. The city encourages such areas to form
committees or other types of associations which will take over the
responsibility or for this supplemental collection. The agency con-
tracts with a contract disposition agency to make the door pick-ups
and assesses its members a charge to cover these costs. The city, thus
freed of its collection responsibilities in that area rebates to the
sponsoring agency 58
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yet recognized the advantages and desirability of strong trade
associations. However, there have been in the recent past, at least
three somewhat loosely organized groups. The most promising of these
around which to build a future strong trade association is the Houston
Containerized Refuse Haulers Association composed of a number of the
major agencies. In the past, this group has presented the case for the
contractors to municipal agencies and state and county control agencies.
Another group is the North Harris County Garbage Association comprising
a.number of the contractors operating on the northern limits and out-
skirts of the city. This group is now inactive. A third group is the
Acres Homes Betterment Committee comprising contractors operating north
of Houston. Their major activity has been the provision of a dump
for their use; the Acres Homes Betterment Committee Dump. These
associations in their present stage seem to have largely ad hoc purposes
and are galvanized into action to handle particular situations as they
arise.
The difficulties of organizing a local or national trade association
when there are so many part time practitioners are notorious. However,
the times require it and this is particularly true of Harris County
where half the solid waste in the city of Houston is collected and
disposed by contractors and where the municipality has shown an unusual
degree of initiative in conceiving, proposing and carrying out waste
disposal practices.
REDUCTION AND DISPOSAL FACILITIES IN HARRIS COUNTY
As part of the study, an attempt was made to locate all non-private
reduction and disposal facilities in Harris County. By non-private is
meant those facilities which accept waste from producers or collectors
other than the owner or operator of the facility.
Table 2 lists facilities categorized by ownership and service scope. This
list does not purport to include every disposal facility in the county,
but does result from information supplied by the knowledgeable persons
interviewed during the three-day field campaign in the county. It
also includes, of course, the information developed from the Phase I
study of the city of Houston itself. It does not include the private
facilities such as the private dumps of industrial establishments nor
does it include private reduction facilities such as industrial incin-
erators. No doubt there are additional non-private facilities which
could be located by a more extended search. In addition, it is known
that there are numerous casual and clandestine dumps which are
receiving non-private as well as private wastes presumably for the most
part on a quite temporary basis.
While on the subject of small dumps, mention can be made of an unusual
practice carried out in the areas just north of and adjacent to the city
where a number of contractor and merchant dumps are located on the map.
Many of the existing dumps there, including some of the larger ones,
are located on land which was originally well below the present highway
level and have been built up by dumping to as much as fifteen or twenty
feet above the present highway level.
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TABLE 2
REDUCTION AND DISPOSAL FACILITIES SERVING HARRIS COUNTY
Tons
Per
Year
Acres
HOUSTON OWNED FACILITIES SERVING HOUSTON
Patterson Street Incinerator 60,800 3.17
Kelley Street Incinerator 60,800 15.95
Velasco Street Incinerator 40,500 4.35
Holmes Road Incinerator 24,900 265
Holmes Road Facility 560,000 265
CONTRACTOR OWNED OR MERCHANT FACILITIES SERVING
INDUSTRY AND OTHER COMMUNITIES
Proler Steel Company Dump and Salvage
Red Jones' Dump
Granma's Dump 46,800 11
Marshall's Dump
A. D. White's Trash Dump 2,000 6
Shepard's Trash Dump
Buckingham's Dump
Wylie's Dump 31,000 15
Alvin Ray's Selective Dump 2,000 10
Hall's Dump
Washington's Dump
Green's Bayou (Rice Hulls)
Unnamed Dump (Near Crosby)
Mansfield Road (Rice Hulls) 3,200 15
Tank Lake
Rams ey's Dump
Fall's Dump 15
GOVERNMENT OWNED FACILITIES SERVING OTHER COMMUNITIES
15
10
10
15
10
Bellaire Sanitary Landfill
West University Place Sanitary Landfill
Galena Park Dump
Pasadena Dump
La Porte Dump
Baytown Dump
Humble Dump
Tom Ball Dump
County Dump
Webster Dump
NASA Sanitary Landfill
21,300
21,200
53,250
8,200
36,100
Ellington Air Force Base Sanitary
Jersey Village Dump
Katy Dump
Landfill
75
75
11
3
30
25
30
8
10
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MERCHANT FACILITIES SERVING OTHER COMMUNITIES
Acres Homes Betterment Committee Dump
NEW FACILITIES PLANNED OR UNDER CONSTRUCTION IN
HOUSTON'S PROGRAM
Lone Star Organics, Inc. Compost Plant
United Compost Services, Inc. Compost Plant
National Organics Compost Plant
Wallace Industrial Contractors Incinerator
New Holmes Road Incinerator
New Unnamed Incinerator
Reed Road Sanitary Landfill
Tons
Per
Year
93,600
93,600
93,600
93,600
249,600
187,200
111,000
Life
Acres (Yrs.)
89
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The unusual practice constitutes an extension of this idea. Persons
will purchase a small city lot as small as 50 x 100 feet and then will
proceed to sell the very substance of the lot itself, namely the soil
comprising it. Excavating machinery will be brought in and will
excavate down to a depth of some 40 feet exactly on the lot lines, such
that the lot comprises a pit with vertical sides 40 feet deep. The
dirt is sold for construction fill and landscaping purposes elsewhere
in the metropolitan area. The owner then has a garbage dump which he
operates as a merchant dump until it is filled and sometimes until it
is more than filled, standing high in the air with refuse. The
entrepreneur owner has treated the lot not as real estate, but actually
as a commodity, indeed twice once selling the substance of the lot
itself as a commodity and then selling as another type of commodity
the space created by selling the first. Since Houston has no zoning
laws, there is nothing limiting this practice except the law of gravity
which sets the angle of repose that can be reached by the final pile.
Such things are going on in the midst of inhabited areas where there
may actually be dwellings on each side of the ravished property.
Several such sites were inspected all in various stages of excavation
of the first commodity, and none as yet having received any of the
second.
With that introduction to the periphery of the local practice, attention
is now turned to the more normal municipal and merchant or contractor
owned operations, recited in decreasing rank of the excellence of
current performance. While the inspection was performed in 1967, the
discussion will be confined to the operations prior to the placing on
stream of the first of Houston's new operations, namely the composting
plant. With that exception, the best run disposal facilities in the
county are the sanitary landfills of Baytown, Bellaire and West
University Place. These are very satisfactory operations, truly
classifiable as sanitary landfills with no loose papers blowing around
and with covering each day. The Bellaire and Baytown operations take
care of all the community waste, other than industrial self-disposal,
but West University Place handles only the municipal pick-up; the
commercial collection going to Houston's Holmes Road facility.
Ellington Air Force Base also operates a sanitary landfill, though
this was not inspected.
The Holmes Road facility of the city of Houston has been in use for a
considerable period and has borrowed its philosophy of life from the
oil fields which surround it namely its anticipated future life
is only a few months, but this has been the situation for at least
five years. As a result, there is practically no cover left on the
site and this must be hauled in from elsewhere. Under these circum-
stances, the operating personnel are performing valiantly in an attempt
to maintain a sanitary landfill status.
The Government owned dumps which were inspected are checked in Table 6.
The contractor owned or merchant dumps are operated with rudimentary
engineering skill in placement and control, but none appear to have
an intention of an earth cover even as a final stage. Most of them
appear to have the plan of building up the deposit about the level of
the surrounding land and the highway level. Most of these dumps,
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however, appear not to accept garbage, so the sanitation from the
health and odor standpoint, is not as bad as it might be. Very little
burning is practiced at the contractor owned and merchant dumps
inspected.
While this recitation of the merchant and contractor dumps may sound
sub-standard, these dumps serve a real economic purpose, in an interim
period extending over many years in the past during which neither the
city nor the county has been able to provide adequate disposal facilities
for the community's wastes.
D. WASTE QUANTITIES
This study attempts to estimate the waste generation of the county,
excluding that portion of the industrial waste which is self-disposed.
The waste streams covered are as follows:
1. Wastes collected by municipalities which reach reduction or ultimate
disposal almost exclusively in municipal facilities.
2. Wastes collected by contractors or handled by private generators
which reach reduction or ultimate disposal in municipal facilities.
3. Wastes collected by contractors or having disposition by private
parties which reach ultimate disposal in merchant or contractor
owned facilities.
The difficulties of achieving this goal are forbidding, but they are of
universal application and, therefore, their discussion is relegated to
the more general portions of the overall project report.
The largest contributor to the total waste stream is, of course, the
community comprising the city of Houston. The city, prior to the new
plan, collects and disposes of 600 tons per day in its four incinerators
and 900 tons per day to the Holmes Road facility. Contractors collect
from the Houston community an amount equal to the city collection of
which 900 tons per day goes to the Holmes Road facility and 600 tons per
day goes elsewhere. The total for Houston facilities is, therefore,
3,000 tons per day or 935,000 tons per year, corrected for the known
small amount to Holmes Road from West University Place this becomes
928,760. Probably this is not the only disposition from other com-
munities in Holmes Road, but the study developed no information on these.
The quantities going to the city facilities are measured (by loads)
and studies had been made giving the average weight per load. Thus, the
uncertain quantity so far is that taken to non-city facilities by
contractors. An independent estimate of this based on a study made a
few years ago is 500 tons per day. One of the major contractors was
interviewed, yielding the information that 38% of the material handled
by this contractor went to non-city facilities. If this is typical of
the total contractor stream and the total amount handled by contractors
is equal to that handled by the city, 1,500 tons per day, this would
indicate 570 tons per day to non-city facilities. A fourth figure may
be generated by summing the estimated daily tonnage to the merchant and
contractor owned dumps immediately adjacent to the city.
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There are fourteen of these known to be operating, not including the
Proler Steel Company dump which takes incinerator residue. Of these,
five have been inspected and estimated to take a total of 85,000 tons
per year. If the remaining nine have the same average capability as the
inspected five, the total would be 238,000 tons per year or 760 tons
per day. When this is corrected for the estimated quantity from the
enclave communities of Spring Valley, Hedwig, Hunters Creek, Piney Point,
Bunker Hill and Hilshire Village known to now go to these dumps, the
figure becomes 730 tons per day. From the four figures 600, 500, 570,
and 730 tons per day, the average is 600 tons per day, which is the
figure used.
By interviews of the municipalities and disposal facilities, there
were developed for a number of communities the community waste generation
excluding that having private disposition and disposal. These waste
generation data varied from 1.75 to 9.54 pounds per capita per day.
It should be noted that the new communities surrounding the NASA
installation in the southeast part of the county have not been included
in the waste projections or in the 1966 populations. The reason is
first that there is little chance of interaction with Houston, but more
important, the economic and population development in these communities
is so extreme as to defy numerical analysis when combined with the rest
of the county. The NASA facility, having incidentally its own sanitary
landfill, has generated around it a number of very rapidly growing
residential communities Webster, Clear Lake City, etc. Five years
ago, that entire area had no more than 5,000 population. Now it has
35D000 and by 1970 it is expected to have 250,000.
E. INTERACTION AMONG MUNICIPALITIES
De spite the predominant role of Houston and particularly with its
dynamic new program for solid waste development, it is surprising that
there is not more existing and planned interaction among the municipalities
of the county. The only present interactions are that South Houston and
Deer Park dispose in the Pasadena dump, the very small communities of
Morgans Point, Shore Acres and Lomax dispose in the La Porte dump, and
some contractor-collected waste from West University Place is disposed
to the Holmes Road Facility of Houston. Two small communities,
Crosby and Highlands, avail themselves of the county dump. There are
some instances of communities disposing outside their own borders; for
example, Bellaire and West University Place and the enclave communities
of Spring Valley, Hedwig, etc. However, these do not actually involve
interactions between Governmental units. The only known instances
in which waste crosses county line is that for Baytown whose sanitary
landfill is located just across the border in Chambers County, and that
for Katy (which lies partly in Harris County) which uses a contractor
leased dump in Waller County.
Not only is there little existing interaction between communities, but
also very little is planned or encouraged. None of the municipalities
interviewed indicated any desire to, in the future, utilize the facilities
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of or offer their own facilities to other municipalities. Even
Houston with its dynamic program is confining itself entirely to its
own wastes and making no provision for taking in some of its small
neighbors.
F. HOUSTON'S SOLID WASTE PROGRAM
Except for the city of Houston, the remainder of the county is in
general not in a critical condition regarding solid waste disposal.
Many of the dumps and sanitary landfills have ten and fifteen and up
to thirty years of remaining life, although the increase of population
by that time will probably make it difficult to locate the next facilities
as conveniently to the communities as the present ones. The exception
is Pasadena which must immediately seek new disposal facilities. A
few years ago, there were some preliminary discussions concerning a
joint incinerator to be used by Pasadena, Deer Park, La Porte, other
communities and possibly some of the industries. However, nothing came
of that particular approach.
Some of the more progressive contractors and possibly through their
association are considering close-in facilities. For example, one has
studied the possible use of a small waste reduction facility. In
addition, there had been some sporadic attempts in the past, mentioned
in connection with the associations, to provide disposal facilities for
the contractors serving the north part of Houston and the county north
of Houston. This is the region not well served by the Houston city
facilities of which only the Holmes facility is open to contractors.
With this quiscence and status quo in the rest of the county, all the
more predominant in solid waste affairs in the county is what has been
referred to in this report as "Houston's program for solid waste develop-
ment". The next section is devoted to this program.
A study in 1964 conducted by Black and Veatch indicated the critical
situation in the city's incinerators and the then Holmes Road facility.
The four existing incinerators were not worth remodeling for future use.
The exhaustion of the Holmes Road facility was recognized as was the poor
placement of that facility the only one open to the contractors.
The study recommended several new incinerators more strategically
placed to serve the entire city, the details to depend upon a policy
decision by the city as to the extent to which they would accept
contractor dispositions.
In Implementing these recommendations, Houston took several bold
directions. This dynamic program has focused national interest in
solid waste disposal on Houston and the outline of the program and many
of its details have received extensive publicity. What will be reported
here necessarily repeats some of this information.
First, Houston has under construction a new 800 ton per day incinerator
on the Holmes Road site due to be completed September 1967. The first
furnace will be put on test the latter part of May and the second in
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June. All material into this plant will be weighed. Cans will be
separated magnetically, crushed, hot washed and put in containers
for sale as scrap metal. Two of the old incinerators will be shut down
when the new incinerator is on stream. The city plans to permit
contractor disposition if they use hydraulic type trucks. They plan to
permit this use by the contractors for the same low prices as now charged
for use of the Holmes Road facility, namely a $5/year license fee and
50o/load for trucks greater than one ton and 25c/load for trucks less
than one ton if the material comes from within the city. If the material
originates outside the city, the charges are $1 for over one ton and
50c for less than one ton. Obviously, these prices are much less
than the costs of operating the incinerator and even lower than the
costs of operating the present facility. However, the city considers
that provision of disposal means is one of its public responsibilities.
An attempt will be made to operate the new Holmes Road incinerator in
a highly exemplary manner such that public education will be achieved
and possibly public acceptance of incinerators at other locations of
the city will result.
As an interim measure, the city opened the Reed Road sanitary landfill
in the fall of 1966. This operates with the pit and ramp system building
the ultimate level to about twelve feet above the original level. On
inspection, the general appearance was very clean and workmanlike,
although it happened that the day's deposit was not covered on the day
of inspection. Excess cover from Reed Road is being used for cover at
the Holmes Road facility. At present, Reed Road is taking city-collected
garbage which would otherwise have gone to Holmes Road or the incinerators
at a rate of 360 tons per day or 111,000 tons per year. Public acceptance
of waste disposal facilities in Houston is poor and because of it,
although the appearance of the Reed Road facility at present is very
good, it is planned to build up the deposit first on the periphery of
the area so as to form an enclosure keeping the remainder of the
operation from open public view.
In addition to the 800 ton per day incinerator, Houston has also just
let the engineering contracts for a second new incinerator, the size
to be determined by the amount of bond funds available and probably about
600 tons per day. Among the decision factors leading to the new
incinerators (rather than sanitary landfill) were lack of land within
what was judged to be a reasonable haul distance, technical problems
encountered with current land fill operations, and the sub-politics
of locating sanitary landfill facilities.
Houston is not alone among cities planning new and constructing new
incinerator facilities. The unusual element in Houston's approach is
the concept of contracting with private companies for waste disposal.
Houston has contracted with a private firm, associated with Wallace
Industrial Contractors and Wallace Plumbing Company, to take 300 tons
per day of waste and to dispose of it. The city will pay the contractor
$3.50/ton of waste delivered, at which point the city will literally
wash its hands of the refuse. The Wallace concern is planning to con-
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struct an incinerator of modern design and the city has offered the site
of the Patterson Street incinerator for this purpose. The operation
is permitted to take other wastes in addition to the city's as long
as the city contract commitment is met.
However, the boldest portion of the dynamic program comprises three
additional such "wash your hands" contracts with concerns who will
build composting plants. In contrast with incineration, composting is
a relatively untried reduction method in this country, notorious for
its failures where it has been applied in municipal service in recent
years. The failures have come about not so much through technical
deficiencies, but through the failure to achieve the optimistic market
for the product which was hoped for. By contracting this disposal
service, the city is protected against monetary loss except insofar
as it may furnish the land for the facilities. By contracting the
city has brought to bear private entrepreneurial skills, a commendable
goal being sought by a number of federal and business agencies in
various fields.
If the private operators are successful in living up to their commit-
ments, the city will have disposed of 900 tons per day of wastes (to
the composting plants) wihtout any capital expenditure on its part,
and at a per ton cost less than the probable operation costs alone
of its own incinerator facilities. If such an approach could be of
universal application, the municipal solid waste disposal practice in
the nation would be much advanced. However, the marketing failure of
recent U. S. composting plants indicates that success of future plants
is uncertain and in light of that, Houston must be credited with a
bold step in providing a more than full scale pilot exploration of the
technical and economic possibilities. If the composting plants fail,
Houston will find itself with 900 tons per day of wastes which the
city will have to handle itself by other methods. Thus, the outcome
of Houston's venturesomeness, unusual among municipalities, is to be
awaited with eager interest.
Of the three composting operations, that of the Lone Star Organics Inc.,
a subsidiary of Metropolitan Waste Conversion Corporation, Barrington,
Illinois is the most advanced in Houston. The contract arrangements
with all three composting contractors are practically the same. The
contractors agree to take 150 tons per day of waste, and the city,
if requested, must deliver up to 300 tons per day averaged over six
days. The contractor will handle the wastes completely after delivery.
The contracts include a cost of living index factor to compensate for
cost changes from January 1965 renewable each year. The city pays
about $3.50 per ton for waste delivered and if the plants take more than
1,800 tons per week, the per ton rate drops for the excess. The Lone
Star Organics Plant, locally known as Metro, was visited. The parent
firm has operated a 50 ton per day pilot plant for three years at Largo,
Florida in developing its patented process.
The Houston plant, designed for 300 tons per day is the largest so far
designed. A slight difficulty has been experienced because of unloading
facilities which proved inadequate for the service. The Houston city
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collection trucks work on an incentive basis such that any waiting time
for unloading is a disadvantage to the men. In computing the delivery
to the compost plants, an average of weight is made on each ten loads
in order to project the remaining daily tonnage and loads required.
The city routes its vehicles to the plant in accordance with this pre-
arranged and constantly adjusted schedule. The city attempts to deliver
most of the requirement for the week early in the week to avoid the
possibility of having to increase the delivery rate by diverting trucks
from distant points, etc. toward the end of the week. The first three
days of the week are usually heavier in collections than the last two
days.
The Metro plant is well constructed and well operated and the city is
impressed with the caliber of performance. The flow line starts with a
conveyor which carries the waste past ten salvage pickers. These
operators segregate paper, cardboard, metal and rags. The paper and
cardboard are remarkably clean and are baled for sale as scrap paper.
Tramp metal is separated carefully prior to the hammermills and the tin
cans are ground and delivered directly to the hopper railroad car for
sale. In Houston there is no market for scrap aluminum and it is too
expensive to salvage glass. The remaining material passes to hammer-
mills where it is finely ground including the glass and then it is
conveyed to the digestion vats. The digestion process in concrete
troughs takes about six days and reaches 160 to 170°F. It is planned
to add to the waste some thickened sludge from the city's activated
sludge sewage treatment plants. The compost product after regrinding
is gray and appears fibrous, having the characteristics of a ground
papier-mache and contains 40 to 50% H20. The product is stored in
outside piles where additional microbiological action continues to occur,
generating some heat. The material inspected has a musty garbage-like
odor at close range.
The product is to be sold to large landowners directly as mulch, to
fertilizer manufacturers as filler and to the individual consumer.
In Houston the material is selling in retail stores at 95£/lb. bag.
The yield from the average feed (75% dry matter, 25% H20) is
approximately 9% metal, 4% non-combustible non-compostable residue, 1%
textiles, 10% paper (range 4 - 15%) and 76% compost (at 40% moisture,
46% dry matter in compost and 30% ^0). Questioned about the market-
ability of the product, the plant management indicated that the parent
corporation has been successful in selling every pound of compost it
has ever produced.
The Metro plant is now actually operating, but in the shakedown stage.
It successfully passed the 300 ton per day for six days acceptance test,
but is now running at less than this rate during the shakedown period.
The second compost contractor is United Compost Services Inc., a Houston
based organization. This plant is not as far advanced into the operating
stage as the Metro plant. On the day of the interviews, the plant had
taken 160 tons, but the average tonnage is less than 100 tons per day
at present. The plant is experiencing complaints from the citizens of
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the neighborhood in which it is located. These include some odor
complaints .
The third compost contract is with National Organics Company (Norco) ,
an Atlanta concern. They have not yet broken ground for the plant.
G. THE SUB-POLITICS OF SOLID WASTE DISPOSAL IN HARRIS__COUNTY
By sub-politics or local politics, there is meant the interactions of
municipal departments with each other, of municipalities and Govern-
mental units with each other and of all of these with individual citizens,
groups of citizens, Chambers of Commerce, newspapers, and other vehicles
by which public opinion is translated into local action. In other
cities it has been found that sub-politics is a major factor, sometimes
a major obstacle in solid waste disposal. While the project did not
make a thorough and intensive study of the behind-the-scenes sub-
politics in Harris County, there does not appear to be a great deal of
this in the city and county. This apparently results from the lack of
interaction of solid waste disposal among the municipalities. Each
municipality seems inclined to concern itself only with its own
territory and problems and not to resort to combinations with other
municipalities. Of course, in the city of Houston there was considerable
controversy over the program involving new types of processes and new
types of contractual arrangements. However, this did not seem to be a
permanent obstacle to the program as evidenced by the rapidity by which
it has so far been implemented.
Harris County has had for more than a decade an air and water pollution
agency operating out of the County Health Department and this agency has
brought down more than its share of sub-political controversy. In
part, this stems from the fact that the County was, or has become,
divided into two camps, one strongly for pollution control and one
believing that pollution control to this extent is incompatible with
industrial activity. The County has no laws under which effective
pollution control can be achieved other than the general nuisance laws
and this is highly handicapping to control. For solid waste disposal,
it is, of course, air pollution control that is more deeply involved
than water pollution control and from that standpoint whatever be the
sub-politics the county and the city have done quite well in that little
open burning is practiced on the non-private dumps. The four city
incinerators are not equipped with sophisticated air pollution control
devices and the extent to which they contribute or have been alleged to
contribute to the overall air pollution problem which Houston faces was
not determined by this study. However, the new Houston incinerators
will have very high level air pollution control features, indeed intended
to be exemplary in this regard and therefore, should not enter into
the sub-politics.
The Federal Government agencies involved in solid waste and air pollution
have not been a factor in Harris County. The state of Texas has had a
Water Pollution Control Commission for several years and just recently
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has established an Air Pollution Control Commission which presumably
will in the future begin to impinge upon air pollution problems in
Harris County including those from solid waste if any. However, so
far, these have not much affected the activity.
The Houston Chamber of Commerce is a very active group having participation
by many of the industries in the industrial complex including those
outside the city of Houston. As an example of the intensity of this
group, its Industrial Committee about ten years ago sponsored out of
its own funds contributed by the members an extensive air pollution
survey of the entire city and county which cost several hundred thousand
dollars. A follow-up to this survey was undertaken a few years ago.
At one time in the past,, a sub-committee of the Industrial Committee of
the Chamber initiated some discussions concerning solid waste disposal
in relation to the industrial and residential community. However, this
was not very actively followed up and there has been no activity of the
Committee in the past three years.
The preceding discussion has been in terms of seeking obstacles to
efficient and acceptable solid waste disposal that might come through
sub-politics. None have been shown in Harris County. However, sub-
politics in addition to being a potential for obstacles, also is a
potential for overcoming obstacles and accomplishing desirable ends.
One of these desirable ends in solid waste disposal that can be
accomplished by sub-politics activities is the education of the citizens
and citizens groups and other members of the sub-political structure in
the social acceptability and economic advantage of sanitary landfill and
other forms of modern solid waste disposal.
It is true that Harris County has at least three exemplary sanitary
landfills, but one of these is remote from Houston and the other two
have not been played up in an education program. The operations which
are readily viewable, namely the dumps north of town and the Holmes Road
facility, do not at present offer good possibilities for an educational
campaign. One of the difficulties is that there is nowhere in Houston
a completed dump or sanitary landfill which has been converted into
useful and desirable purposes. All of the dumps and fills with the
exception of the completed South Houston dump are still in active
operation or if they are abandoned} as some of the merchant dumps just
north of the city, have been left unrestored. In other cities it is
possible for the public to view completed dumps and landfills which have
been converted to parks, recreational and industrial purposes. Even
common dumps, which are not covered during the course of construction
have been covered and made into park-like areas which the public can
walk upon and in them recognize the future condition of active dumps
and sanitary landfills.
It is not possible to do this in Harris County. It is not surprising,
therefore, that there is public resistance to the location of sanitary
landfills, or dumps as may be feared, or incinerators. It is
particularly unfortunate that sub-politics has not been used in education
toward sanitary landfills, for the city of Houston itself averages only
about fifteen miles in diameter and for the most part has completed its
radial freeways.
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SECTION XI
APPENDIX F
JERSEY CITY, NEW JERSEY
A. DESCRIPTION OF METHOD:
The Jersey City, New Jersey area was analyzed by personal interview
of cognizant people in and around Jersey City. Three major industries
were contacted and their inputs to the waste stream defined. A
representative private contractor was also interviewed. The data
obtained was analyzed to determine interaction of waste streams
between the communities, the amount per capita contributed by each
segment of the metropolitan area such as residential, commercial
and industrial inputs. Historical trends were noted insofar as
historical data was obtainable. Jersey City is a heavily urbanized
community which is surrounded in the main by similar communities.
B. DISCUSSION OF THE DATA:
It was determined that there is no apparent flow of solid waste into
the core city of Jersey City. A flow of approximately 50 tons/day
is being removed from Jersey City to private landfill operations outside
the city by private contractors. The Jersey City Incinerator Authority
operates its incinerator 24 hours a day, five days a week. This
incinerator, which is actually made up of four 150 ton capacity furnaces,
has a 600 ton/day capacity and was installed in 1957 at a cost of
$2,500,000. Originally the furnaces were equipped with manually
operated ash dumping grates and the standard stoking arms. In 1958,
a hydraulic grate system and a new type of stoking arm was installed.
These modifications allowed a gain of 2,750 pounds of refuse burned
per hour per unit. During the last six months of 1958, they were
able to incinerate 21% more than the design capacity of the incinerator.
Table I shows the amount and origin of refuse incinerated from 1958
through 1965.
From the incinerator figures and population figures as furnished by
the Jersey City Planning Board, the amount of residential and commer-
cial waste per capita has increased from 2.44 pounds per capita in
1960 to 2.89 pounds per capita in 1965, which indicates an increase
of .09 pounds per capita per year.
The Jersey City Planning Board which played a part in creating the
Jersey City Incinerator Authority is now concentrating its efforts
on other social and economic problems within the city. Jersey City
reached its peak population in 1930 (316,715) it has been declining
since then. In 1960, the population was 276,101. It is expected to
decrease to approximately 266,000 in 1975. At that time, it is
expected to take an upturn caused by the fulfillment of the city's
long range planning. The water front area behind the City Hall is
undergoing an urban renewal program and two high-rise apartment
units have already been completed and are being rented. These
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apartment structures do not appear to be renting too rapidly. They
are provided with mammoth parking lots which at the present are
filled with broken bottles and other pieces of glass obviously tossed
in by the juveniles of this otherwise densely populated lower income
region. The Planning Board hopes to see 30,000 apartment type housing
units built in this area with approximately 90,000 residents. The
Planning Board visualizes a sort of bedroom community for New York
City. They hope this influx of New Yorkers will help raise the
current level of economic conditions in the city.
At the present time, there are 2,000 acres of vacant land in Jersey
City, classified and valued as follows:
No. of Acres
34
5
220
Classification
Residential B
Business B
Commercial Light Mfg.
Current Value
$ 9,500 per acre
37,000 per acre
15,800 per acre
1,700 Industrial 10,000 per acre
67 Parks & Cemeteries 6,350 per acre
It is expected that most of this vacant land will be developed by 1985.
Industrial employment in Jersey City has fallen off considerably. In
1954, 562 industrial firms employed 40,829 or approximately 73 employees
per establishment. In 1964, 503 industrial firms employed 28,388 or
approximately 56 employees per establishment. A trend has developed
in that the firms moving out of the city were larger employers than
those moving in. It also is evident that the firms moving in do not
require the higher grades of skilled labor. Thus, lower pay scales
will be prevalent. At the present time, 44.4% of the city's labor
force is employed outside of the city.
One or possibly the largest of the city's employers is a nationally
known manufacturer of soap, detergents, etc. They employ 2,400 people
and operate 49 weeks per year (2 week shut-down in July and 1 week shut-
down in December). This industry does not contribute much in the way
of process waste to the solid waste stream since most of the processes
are chemical and process wastes are collected and reused. Corrugated
cardboard and similar packaging materials are sold to a private
scavenger who bundles and sells it. Office waste and general rubbish
are collected by another private collector and taken at the rate of
two truckloads a day to the Jersey City incinerator.
Another of the city's larger manufacturers manufactures tin cans
and employs 1,800. They operate 52 weeks per year, two full shifts,
and a partial third. They generate general plant rubbish at the rate
of 18 tons per day. This rubbish is compacted in bins and hauled to
a private dump in Pine Brook, New Jersey, approximately 25 miles
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TABLE 1
SOLID WASTE DISPOSAL - JERSEY CITY
MUNICIPAL
Tons Per Month
Year Burn Non-Burn
1958 8,799 552
1959 8,230 116
1960 8,654 70
1961 NA NA
1962 9,434 0
1963 9,335 0
1964 9,746 0
1965 9,165 0
PRIVATE CONTRACTORS
Tons Per Month
Year
1958
1959
1960
1961
1962
1963
1964
1965
INSTITUTIONS, HOSPITALS. SALVATION ARMY, ETC.
Tons Per Month
Year Burn Non-Burn
1958 NA NA
to
1963 NA NA
1964 651 0
1965 306 0
Burn
393
594
448
NA
1,061
1,056
521
968
Non-Burn
84
87
64
NA
276
275
NA
0
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from the plant. Approximately 30 cubic yards of broken pallets and
lumber are removed every week by a private scavenger to an unknown
destination.
The third industry was not as large as the other industries surveyed,
it still has a relatively high rate of employment. This manufacturer
produces iridescent lamps and employs 450. They operate 24 hours a
day, five days a week with a three week shut-down in July. They
generate approximately 10 tons of refuse a day. Besides the general
office, shipping, cafeteria type waste, a considerable amount of
process waste in the form of broken glass is generated. A private
scavenger hauls away two truckloads of this refuse a day to a private
dump outside the city.
Other cities in the area were surveyed to determine if any interaction
existed. In Hoboken, a minimum amount of information was available.
Private contractors handle all collecting and disposal requirements.
At the present time, this city of approximately 48,000 people is generating
600 tons a week of residential and commercial refuse, or approximately
3.0 pounds per capita per day. This figure compares with the basic
figure of 4.4 pounds per capita per day obtained in Jersey City. As
the cities are adjacent to one another and are basically of the same
economic makeup, the correlation of these figures is readily under-
standable and would indicate no cross flows. All of Hoboken's refuse
is removed to private dumps outside of the city.
The city of Hackensack, while not adjacent to Jersey City, is in
close proximity to it. Because very complete records of refuse disposal
were available, this city was also surveyed.
The Hackensack incinerator was built in 1927 at a cost of $90,000. It
has a rated capacity of 100 tons a day and operates ten hours a day,
six days a week. The city of Hackensack completed a "garbage collection
and incinerator study" in May of 1966. This study clearly points
out the needs of this city of 35,000 people. Basically, the present
incinerator is operating on a day-to-day basis. It is constantly under
repair and cannot operate too much longer. There is no vacant land
within the city, the closest being 7 1/2 miles away.
A city supervised, privately owned landfill area is currently being
used. This area was originally five acres 2 1/2 acres have been filled
in and it is expected that in another five years, this site will be closed.
There are approximately 15 apartment houses which have their own inciner-
ators within the city limits. It has been estimated that the population
of Hackensack, which decreased in the period from 1950 to 1960, is on the
increase and will double within the next 20 years.
The refuse processed at the incinerator has increased from 12,383 tons
in 1952 to 18,685 tons in 1965. At times during this period, the incin-
erator has been operated at 30% above its rated capacity. Both city
and private contractors collect refuse in the city. Due to the
limited capacity of the incinerator, only 40% of the total garbage
and refuse collected in 1965 was incinerated. This type of refuse
represents 60% of the total refuse generated by the city. Wood,
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bulk trash, logs, etc. are not presented to the incinerator. Residential
and commercial refuse amounts to approximately 4.2 pounds per capita per
day in Hackensack. Industrial refuse amounts to 1.7 pounds per capita.
It is predicted that this figure will be fairly constant as the city's
population increases. There is no indication of any refuse being
collected elsewhere and brought to the city, but several private
collectors are hauling refuse to private dumps outside the city.
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SECTION XI
APPENDIX G
NORWALK, CONNECTICUT
A. DESCRIPTION OF METHOD
The Norwalk, Connecticut metropolitan area was analyzed by personal
interview of cognizant people in Norwalk. The three satellite towns
of Westport, Weston and Wilton were also interviewed. Four major
industries were contacted and their inputs to the waste stream defined.
A representative private contractor was interviewed as was the Director
of the South Western Planning Region. The data obtained was analyzed to
determine interaction of waste streams between the communities, the
amount per capita contributed by each segment of the metropolitan area
such as residential, commercial and industrial inputs. Historical
trends were noted in so far as historical data was obtainable. Norwalk
is an industrialized community, but also a suburb of New York City. It
has its own suburbs which range from no industry to light industry.
B. DISCUSSION OF THE DATA
It was determined that there was no apparentflow of solid waste from the
core city of Norwalk into the satellite communities. The Norwalk figures
for 1965-1966 were running at approximately 240 tons per day burned in
a five day week or 4.1 pounds per capita generated over a seven day
week. In 1958 the amount burned was only 120 tons per day on a five
day week basis. No per capita figure is able to be calculated because
it is known that an indeterminate amount of refuse now being burned
in an incinerator in those days went directly to a landfill.
The 4.1 figure consists of residential, commercial and industrial waste.
The residential and commercial figure alone is approximately 3.0 pounds
per capita. This material is handled by two incinerators in the city
of Norwalk. The old plant which was constructed in 1940 and remodeled
in 1952, operates eight hours a day and is rated at 150 tons. The new
plant was built in 1962 at a cost of $1,050,000 and was rated at
360 tons and operates 14 hours a day. Operating cost of the incinerator
and dump without amortization is $3.46 per ton.
Incineration was chosen as a waste reduction method for the city of
Norwalk, primarily because land was becoming both scarce and expensive.
At this time, this was the overwhelming factor in the selection of
incineration rather than some alternate waste disposal method.
The anti-pollution equipment used in the new Norwalk incinerator consists
only of a water wetted baffle chamber,, It is not known how much water
was used but that the effluent water is treated in a clarifier and
recycled. The waste water is dumped in the harbor. It wap stated that
the incinerator was operating satisfactorily from an air pollution
standpoint, except when heavy industrial charges of rubber and like
materials were charged. They have no plans now for further air pollution
equipment.
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The surrounding towns have no waste reduction facilities per se, but use
various grades of sanitary landfill varying from an open dump to a
sanitary landfill operation.
The town of Wilton at the time of the interview had no landfill in
its boundaries and was using a dump in the neighboring community of
Weston to dispose of the 91 1/2 tons or 2.4 pounds per capita generated.
The town of Weston was also using this facility (which is in Weston) to
dispose of its 45 tons per week or roughly 2.1 pounds per capita. This
facility is a privately owned facility and is a dump not a sanitary land
fill. Because of new state regulations, the town of Weston may take
over the operation of this dump and run it in a sanitary manner. The
town of Wilton would not be permitted to use it under these circumstances.
This situation has been anticipated by Wilton and acreage within their
community boundaries was obtained for the landfill.
At present an injunction exists against the city using this land for its
intended purpose. The injunction was obtained by residents near the
proposed site. This situation will be discussed further in a later part
of this report.
The town of Westport conducts a landfill operation which is not in accord
with the standards normally used to designate a sanitary landfill. Its
per capita refuse is 2.7 pounds generated.
In the core city of Norwalk, only 80 acres remain which could be
considered as available for refuse disposal. This land is shore land
and is marshy. It would have to be considered very poor with serious
building limitations. This land, however, may not remain available for
the purpose of refuse disposal as conservationists are interested in
preserving it for its value to migratory water fowl, Norwalk being on
one of the major Canadian duck and geese flyways. On the other extreme,
the town of Westport has approximately 1,500 acres of vacant land. The
neighboring residents of any proposed new land fill area are the primary
obstacles to the selection of land. This will be further noted under
the discussion of the Wilton situation.
It is interesting to note that the communities of Weston and Wilton, which
are strictly residential in nature having no industry and a very minimum
amount of commercial activities within their boundaries, generate from
2.1 to 2.4 pounds per capita.
Westport, which is a town which has commercial activity, reflects this
in the pounds per capita generated by having a 2.7 pounds per capita
figure. Norwalk with heavy commercial activities shows 3 pounds per
capita for residential and commercial refuse and a total of 4.1 pounds
per capita when industry is included. It is entirely possible also that
some of the satellite towns' refuse finds its way to the Norwalk facility
which is free for private contractors who pick up refuse in Norwalk.
It is known, particularly in the case of Norwalk, that certain elements
of solid waste are not noted in these figures. No weights are available
on bulky non-combustible items which go directly to the Norwalk residue
dump. A collection of this type material is made in alternate halves
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of the town every other week. The trucks are busy all day and the
volume is substantial. In addition, some salvage of the material and
cardboard is going on and there is no information as to the quantity of
this waste stream. There is also no information available at this time
on the amount of refuse which is disposed of at its source.
Four major manufacturing firms were interviewed in the Norwalk core city
to determine their contribution to the waste stream of the community.
An instrument firm was determined to be generating five tons per day.
Two apparel manufacturers had an average of 1.75 tons per day. A large
food concern generated 2.5 tons per day.
Little inter-community planning is noticeable in the Norwalk area. The
South Western Planning Region was interviewed to see what, if any,
action had been taken toward regionalization or planning. This region
which comprises Greenwich, Stamford, New Canaan, Darien, Norwalk,
Wilton, Weston and Westport was established under the Enabling Act of
the State Legislature. Membership in this planning region is voluntary
and not all of the towns listed are actually members. It was stated
that some towns join the planning region and drop off and rejoin again.
The Planning Region Agency has issued only two reports one on
population and one on land use. They ran last year, in addition, a
refuse disposal inventory. Responses were received from Westport,
Greenwich, Darien and Stamford. Little effective regionalized planning
has been accomplished at this time.
A private contractor was interviewed to give us a picture of the private
collection in the Norwalk area. He stated that for the most part all
waste collected in Norwalk went into Norwalk1s disposal facilities since
there was no charge for dumping other than the normal license fee. He
estimated that private collections handle one third to one half of the
residential and commercial collection within the city, and 100% of the
industrial collection except where self-disposal by industrial plants
was the case. There are five big private collectors that handle
Norwalk's refuse.
If a truck partially loaded from another community continues its route
in Norwalk, there is no doubt that the foreign waste is disposed of in
Norwalk. No special practice is made of this, but it does happen.
The contractor confirmed that there is no major outflow of Norwalk's
generated waste to disposal sites beyond the city. There are two salvage
operations in the city one who handles metal and one who handles
paper and metal. In general, salvage does not seem to be a big item
other than for cardboard salvage from some industrial plants. It appears
that there is not a strong economic justification for much sorting and
salvage of waste collected.
Another large collector also confirmed that very little if any of
Norwalk's refuse was being deposited outside of the city. He also
confirmed the figures and impressions reported in the Wilton and Weston
collection and disposal systems.
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The Chamber of Commerce staff in Norwalk indicated that there was little
community interest in the problem except if rates were adjusted upward
or a landfill is proposed in their neighborhood. The interest that
exists then apparently is one of protest.
Earlier in this report we discussed the Wilton situation where the
community was forewarned that their current disposal site would be
eliminated. The community then took action to obtain another site which
the citizens proceeded to make unavailable by means of a restraining
injunction. The private contractors servicing the community recognized
that at this time they could not legally take Wilton waste into any of
the surrounding communities, making their job an almost impossible one.
They consequently notified their customers of their intention to no
longer collect in the Wilton community after January 1st of 1967.
The following article reprinted in its entirety appeared in the
January 3rd "New York Times" and is, in a real sense, the type of problem
that the nation faces, depicted on a far smaller scale.
NEW YORK TIMES - JANUARY 3, 1967
"REFUSE DISPOSAL WORRIES WILTON"
Connecticut Aides to Meet With Town on Problem Pickups are
Halted
WILTON, Conn., Jan. 3 - No garbage is being collected in the town
and its 12,000 inhabitants are getting worried.
Householders are burning paper in their backyards and fireplaces
and piling other refuse in their garbage cans while waiting for
town officials to solve the disposal problem.
Dr. Henry Appelbaum, the community's director of public health,
is to meet here tomorrow with state health officials to decide
whether to declare a health emergency.
The garbage is piling up because the three private carting
companies that service the town have no place to get rid of it.
The town's problems began early last year when the State General
Assembly passed a law forbidding the dumping of garbage in open
land and the burning of it, in open pits. It gave communities a
year to make other arrangements.
Until today, Wilton's refuse had been carted to an open pit owned
by Anson Morton in neighboring Weston. When the new law was
passed, Mr. Morton told the town to take its garbage elsewhere.
He gave Wilton several time extensions and then set today as the
deadline.
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"WOODLAND ACQUIRED"
In anticipation of the new law, the town purchased 70 acres of
woodland about a year and a half ago for general municipal
purposes. It then built a road to the site and set aside two
acres for use as garbage landfill.
Residents of the area near the projected landfill brought
suit against the town. In November, Superior Court Judge
Anthony J. Armentano granted them a permanent injunction
forbidding the town to use land for garbage disposal under
penalty of a $2,500 fine.
Last week, Dr. Appelbaum wrote a letter to First Selectman
Vincent J. Tito suggesting that the town declare a state of
health emergency. Mr. Tito said that was a function of
Dr. Appelbaum, the health director. Dr. Appelbaum then set
up tomorrow's meeting with state authorities.
Worried Wilton inhabitants were calling town officials and
The Wilton Bulletin, the local weekly newspaper, today for
guidance.
"I tell them to do their best for themselves until a solution
is found," David Gearhart, the newspaper's editor, said. "I'm
sure some solution will be found. It better be soon."
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SECTION XI
APPENDIX H
ROME, NEW YORK
A. DESCRIPTION OF METHOD
The Rome, New York metropolitan area was analyzed by personal interview
of cognizant people. Highway and dump superintendents in the surrounding
towns were also interviewed. In addition, we interviewed the secretary
of the Chamber of Commerce and two major industries. The waste disposal
practices of Griffiss Air Force Base were determined for their influence
on the waste streams in the Rome area. A representative private
contractor was also interviewed.
The data was analyzed to determine interaction of waste streams between
the communities, the amount per capita contributed by each segment of
the metropolitan area such as residential, commercial and industrial
inputs. Historical trends were noted as far as historical records were
obtainable.
B. DISCUSSION OF THE DATA
It was determined that there was little flow of solid waste between
communities, though what there was, was more prevalent between the rural
suburbs as compared to a flow from the core city to the suburbs. The
pounds per capita of solid waste for the core city of Rome was
determined to be approximately 3.0 pounds per capita including commercial
and residential waste. Approximately 50% of this figure was collected
by municipal trucks from the central core city the balance was
collected by private contractors in the outer city. It was impossible
to obtain historical tonnage data. However, it is interesting to
note some actual expense figures presented in Table
Year Waste Disposal Expense
1946 $ 43,000 + $10,000 private contractor
1960 $ 88,900
1965 $108,264
1966 $110,545
1967 $120,377 (BUDGETED EXPENSE)
The pounds per capita figure of 3.0 pounds does not include industrial
waste. The waste is disposed of in a landfill site which is rented at
a nominal cost per month from a private owner. Most of the solid waste
is left uncovered for significant periods of time and some fires are
permitted to burn in the landfill area from time to time. In the winter
time almost no effort is made to cover refuse. Landfill is the chosen
method for the area solely on the basis of economics.
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Land is plentiful and cheap. At least 1,500 acres exist which could
be used as land fill sites. This land is zoned all the way from being
suitable for mobile homes to 15,000 to 20,000 square foot residential
building lots and varies from prime flat high land suitable for
residential development to farm land ranging from good grazing pasture
to swampy marsh. All of this land is within two to three miles of the
center of the Rome area.
There is a definite interaction of industrial waste with the Rome
facility with two major manufacturers disposing of 30,000 pounds per day
each in the landfill. The military installation, however, is kept
separate from the Rome facility and runs a land fill which is no more
sanitary than the one described for the city of Rome. An indeterminate
amount of waste is disposed of in this facility in addition to 152,000
pounds of metal which is sold every year. A small amount of garbage
amounting to approximately 750 pounds per day is sold to a private
contractor for feeding to hogs.
The private contractor who was interviewed indicated that there was
negligible cross flow between communities. The contractor also
indicated that each community was serviced by private contractors who
were able to use the community facility economically and while some
cross flow might occur by virtue of a route which started in one
community and ended in another, there was no major practice of this.
The Chamber of Commerce staff in the core city of Rome indicated that
industry was satisfied with the current operation of being able to use
the city facility and that there was not much self disposal by industry.
There was a great deal of self disposal by residents. It was the
opinion of the Chamber of Commerce staff that better economy could be
achieved with the initiation of transfer stations within the city
where residents would be required to bring their refuse for trucking
by the city to the landfill. The Chamber of Commerce staff also
indicated that there were many complaints about the landfill from
residents in the surrounding area. The complaints indicated that the
landfill faas continually smoking from the fires going on and that the
roads in the area were dirty by virtue of refuse blowing off the open
trucks of private contractors and industry.
The surrounding towns are best described by the example of the town of
Lee, New York.
The town of Lee, a small semi-rural community, maintains its own dump
which is open from 2-7 p.m. on Tuesday, Thursday and Friday and on
Saturday from 8 to 5. The dump is about five acres in size and is being
utilized in a rather ingenious manner. Twice a year a long trench about
15 feet deep and 10 feet wide is excavated and the refuse is dumped
under supervision in progressive areas along this pit. The refuse is
burned in the pit and subsequently covered with fill from the excavation.
In this manner, a clean and orderly dump is maintained and the life is
estimated as twenty years or more. In fact, it is probable that some of
the early areas may be retrenched and utilized in a similar manner when
the site is filled.
-68-
-------
A great many of the people in town carry their own refuse to the dump.
There is only one contractor operating who utilizes a small packer truck
about 16 or 17 yards in capacity. This contractor picks up in town
six days a week, usually two loads a day and on the day when the dump
is closed he disposes of refuse on his own farm.
It is thought that there is some cross flow of the refuse between Rome
outer city and Lee, but it is believed that the amount is negligible.
This operation seems to be satisfactory for this belt type city and
indeed the villages of Taberg in the town of Annsville and Westernville
in the town of Western have adopted exactly the same disposal methods
within their town boundaries. These towns are small and the town
official (called the supervisor) works on other jobs and is not available
generally for supervision and information on refuse problems.
As an estimate, some 35 yards per day average are picked up by a
private collector in the town of Lee, six days a week. This is probably
equivalent to about 1,200 pounds per day. It should be noted that this
represents only a fraction of the total waste generated within the town
since most of the people dispose of their own refuse. As noted above,
an exactly similar situation exists in other small surrounding towns.
-69-
-------
PART 3
MATHEMATICAL MODEL
Prepared by
Joseph H. Bacher
Administrative Engineer
Product Diversification Department
-------
TABLE OF CONTENTS
Page
I. INTRODUCTION TO MATHEMATICAL MODELING 1
II. NATIONAL MODEL 3
III. CONNECTICUT MODELS 30
IV. REFERENCES 52
V. APPENDICES
A. WESTERN UNION QUESTIONNAIRE .......... 53
-i-
-------
SECTION I
INTRODUCTION TO MATHEMATICAL MODELING
A. METHOD OF APPROACH
This section of the report describes mathematical methods to estimate
solid waste production and installed waste reduction capacity in 1975.
Two mathematical models are presented. The first, a national model, uses
data collected from the forty^eight continental states to predict
installed waste reduction capacity in each of these states in 1975. The
second, a model of the state of Connecticut, uses data generated in a
transportation" study to predict installed waste reduction capacity
and municipal and industrial solid waste production in Connecticut in
1975. Many states are presently developing "transportation" studies for
their highway programs, and may be able to use the concepts presented in
this report to develop their own mathematical models for solid waste
planning purposes.
B. MATHEMATICAL MODELING
Mathematical models are mathematical equations which use one or more
known variables to predict one or more unknown variables. The equations
mathematically represent past trends and can be extrapolated to the
future assuming past trends continue.
The mathematical models developed utilized linear regression techniques.
Linear regression analysis is a statistical technique used to determine
the mathematical relationship between a dependent variable (Y) and a
set of independent variables (X]_, X2 , ... Xn) . An equation of the form
Y = a0 + aiX! + a2X2 + . . . + anXn + tsy
is obtained when linear regression analysis has been applied to a set of
data. The numerical values of the a's are such that the sum of the
squares of the vertical distances between the data points and the
straight line representing the equation is minimized. The tsy in the
above equation is a mathematical representation of these vertical
distances .
The standard deviation, ay, is a measure of the spread of the data about
the mean of the Y's. There is a 68% chance that a random value of Y will
fall within ay of the mean of the Y's. The standard error of the
estimate, sy, is a measure of the spread of the data about the linear
regression line. When t = 1, there is a 68% chance that a random value
of Y will fall within ±sy of the value predicted by the line. Where
t = 2, there is a 95% chance that a random value of Y will fall within
+2sy of the value predicted by the line.
The correlation coefficient, R, is a measure of how well the equation
represents the data. R is defined so that 100R2 equals the percent of
the variability of Y that is accounted for by the relationship with
-1-
-------
the X's. In mathematical form:
R =
For this study Combustion Engineering used a regression analysis
computer program that provided the ability to consider non-linear as
well as linear relationships. This additional capability allowed for
a more exact analysis of solid waste reduction capacity needs. The
computer program also selected the best combination of variables; all
variables which had coefficients with confidence of less than 95% were
eliminated from the equation. In other words, all regression equations
predicted in this report are given with 95% confidence.
While regression analysis is a valuable tool for mathematical model
building, consideration must be given to the possible misuse of it.
The use of regression analysis can result in invalid predictions
because of the assumption of non-existing cause and effect relationships
For example, we do get an extremely high linear correlation by
considering the increase in alcohol consumption with the increase in
teachers' salaries. It is recognized that no cause and effect relation-
ship exists in this example. The example illustrates two changes in
our environment with no real relationship. The above example is to
emphasize the need for "common sense" judgements in gathering input
information for any computer analysis of sets of interrelated variables.
In addition, the use of regression equations to predict the future
implies that the historical relationship between the variables will
remain constant over time; i.e., the coefficients ao, a]_ ... etc., will
remain constant. Any changes in these relationships and, hence, in the
constants will introduce errors into the predicting equation.
-2-
-------
SECTION II
NATIONAL MODEL
A. MODEL CONCEPT
This section discusses the data used for the national waste reduction
model and how this data was combined into a set of variables which was
used in linear regression analysis. Linear regression analysis resulted
in two equations, a complex one and a simplified one. These equations
were then used to project national solid waste capacities for 1975 by
state. The complex model involves several physical quantities as
independent variables whereas the simplified model uses only two
physical quantities as independent variables.
B. DESCRIPTION OF VARIABLES
Tables 1 to 6 and Figure 1 summarize the statistical information gathered
on installed waste reduction facilities in the United States. The infor-
mation was collected in three ways: (1) Combustion Engineering personnel
personally interviewed officials in fifty cities, (2) a telephone survey
of approximately six hundred cities was conducted by the Western Union
Telegraph Company using the questionnaire in Appendix A and (3) telephone
interviews were made with personnel of the State Health Departments to
verify Western Union responses.
Due to the nature of the personal interview and the experience of the
interviewers, the statistical data gathered by Combustion Engineering
personnel was assumed to be correct. The Chi square test was used to
test the significance of the results and a linear correlation analysis
was performed to determine the relative accuracy of the data. The
correlation coefficient of personal interview data with Western Union
data was .97. A comparison of the data gathered by the three methods
revealed exact agreement in the responses of two-thirds of those cities
which reported waste reduction facilities. The standard error of the
mean installed capacity was approximately 16.5% in a town, with a much
lower percentage error on a per state basis of approximately 8%. Since
state values were obtained by adding up the values for each city , the
resulting error in the state value is equal to the square root of the
sum of the squares of errors in the city data. The Western Union data
was combined with the other data to provide the dependent variable, tons
of installed waste reduction capacity by state.
The choice of the independent variables was based upon the assumption
that solid waste reduction capacity was primarily dependent upon two
factors: (1) amount of refuse generated and (2) amount of land available
for land fill. The first factor was based on the assumption that solid
waste reduction capacity, when installed, is directly dependent on the
amount of waste produced. The second factor was used to determine when
waste reduction is required. It is well known that while land fill
which is the primary alternative to waste reduction is relatively
inexpensive to operate, it is also relatively extravagant of land.
Incineration reduces the bulk volume of the solid waste by about 80%,
accounting for significant land savings. Consequently, areas with little
-3-
-------
TABLE i
STATISTICAL SUMMARY OF SURVEY DATA
FOR NATIONAL MATHEMATICAL MODEL
State
Alabama
Arizona
Arkansas
California **
Colorado
Connectciut **
Delaware **
Florida **
Georgia **
Idaho
Illinois **
Indiana **
Iowa
Kans as
Kentucky
Louisiana **
Maine
Maryland
Massachusetts
Michigan **
% of Population
Greater than
50,000 Sampled*
(See Note 1)
100.0
100.0
100.0
94.0
100.0
100.0
100.0
95.9
80.7
AAAA
98.9
95.9
100.0
100.0
100.0
100.0
100.0
100.0
90.4
92.9
% of Population
Between 25^000^ &
50,000 Sampled*
CSee Note 1}
AAA
AAA
AAA
83.5
AAA
100.0
AAAA
A* A
A A A
AAA
73.4
75.9
AAA
AAA
jUj^ ^
82.9
88.7
88.3
KLumhe.r of Replies
From Cities
Greater than
50,000
6
2
3
38
3
10
1
9
4
0
14
8
7
3
3
5
1
5
17
17
Number of Replies
Received Between
25,000 and
50,000
0
0
0
47
0
16
0
0
0
0
22
8
0
0
0
0
0
5
25
17
-------
STATISTICAL SUMMARY OE SURVEY DATA
FOR NATIONAL MATHEMATICAL MODEL
(2)
i
Ul
I
Minnesota
Mississippi **
Missouri **
Montana
Nebraska
Nevada
New Hampshire
New Jersey **
New Mexico
New York **
North Carolina **
North Dakota
Ohio **
OkLahoma **
Oregon
Pennsylvania **
Rhode Island **
South Carolina **
South Dakota
Tennessee **
Texas **
Utah
Vermont
Virginia
Washington
100.0
100.0
100.0
100.0
100.0
100.0
100.0
93.0
100.0
96.9
100.0
A***
95.1
100.0
100.0
97.2
100.0
100.0
100.0
100.0
98.4
100.0
A***
83.5
100.0
A A*
***
Aft*
***
ft* ft
Aft ft
ftft*
94.4
ft*ft
79.5
* **
***
91.3
A A*
A Aft
100.0
100.0
AA*
***
***
A A A
AAA
AAA
100.0
AAA
4
1
6
2
2
2
1
15
1
15
7
0
15
3
2
19
4
3
1
4
20
2
0
7
3
0
0
0
0
0
0
0
31
0
20
0
0
20
0
0
20
3
0
0
0
0
0
0
3
0
-------
STATISTICAL SUMMARY OF SURVEY DATA (3)
FOR NATIONAL. MATHEMATICAL MODEL
West Virginia ** 100.0 100.0 3 4
Wisconsin ** 92.7 92.9 6 10
Wyoming **** *** 0 0
304 251
i
ON
I
NOTE:
Cities were placed in one or the other strata by population existing in. city as recorded by 1960 census.
Note 1 Represents total population sampled as a percentage of ±otal population ..in all cities in this
population range.
* Sampled by Western Union and personal interview.
** State Health Department contacted by telephone for further verification of state totals.
*** Cities between 25,000 and 50,000 were surveyed only in- the states listed, in technical protocol.
**** State has no cities in this strata.
-------
TABLE 2
SUMMARY OF INSTALLED WASTE REDUCTION CAPACITY 1966 IN OPERATION
I
i
I
State
Alabama
Arizona
Arkans as
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Installed Capacity
Ibs/day/person, Cities
Larger than 25.000
Less than 50,00
A
A
A
0.0
3.3
A
4.6
0.9
AA
0.0
1.9
A
A
A
A
A
0.0
2.8
2.5
Installed Capacity
Ibs/day/p.erson, Cities
Larger than 50,000
0.0
0.0
0.0
0.0
0.0
9.4
0.0
6.3
3.5
AA
1.7
0.6
0.0
0.1
5.3
3.7
0.0
4.3
2.8
1.7
Total Installed
Capacity for
Cities*** (1966)
Tons/Day
0
0
0
0
0
4960
0
5320
1855
0
3960
835
0
35
1350
1940
0
2574
4690
3550
-------
SUMMARY, OF INS.TALLEU IsZASJIEL JBFJlTTfTTTnN .JIAEA..^TTY JJjjjjxJJLQgERATION
(2)
Minnesota
Mississippi
Missouri
Montana
Nebraska
*
1.1
0.5
0.0
1.3
0.0
0.0
225
144
1000
0
0
i
00
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
1.1
*
8.1
1.1
*
*
2.9
3.8
*
0.0
1.7
2.8
0.9
0.0
2.8
0.0
&*
2.2
0.0
0.3
2.7
2.7
0.0
0.0
0.0
0.4
2.3
A*
2.7
0.0
100
125
1424
0
21042
0
0
4840
0
60
6325
865
0
0
0
924
300
0
1710
0
-------
SUMMARY OF INSTALLED. JM.R.TK .-R^nTTC^QN: ,CA£AJlCrX 1.9 fid JH^OgERAJim (3)
West Virginia 0.0 2.7
Wisconsin 3.6 3.0
Wyoming * **
TOTAL 73078 tons/day
NOTE:
Cities were placed in one or the other strata by population existing in city as recorded by 1965
census.
* Cities between 25,000 and 50,000 were surveyed only in the states listed in technical protocol.
** State had no cities in this strata.
*** Capacity was obtained by projecting Western Union and personal data to include entire state
population. This total state capacity was reviewed with state health officials in selected
states.
-------
TABLE 3
INCINERATORS IN THE UNITED STATES
OPERATING IN 1966
Capacity
State
CONNECTICUT
Installed Operating Capacity
4,960 tons/day
DISTRICT OF COLUMBIA
Installed Operating Capacity
1,500 tons/day
FLORIDA
Installed Operating Capacity
5,320 tons/day
GEORGIA
Installed Operating Capacity
1,855 tons/day
Greenwich
Darien
New London
Stamford
Derby
Waterbury
Hartford
New Britain
New Canaan
East Hartford
West Hartford
Bridgeport
Stamford
Bridgeport
Greenwich
Norwalk
New Haven
Stratford
West Haven
Washington
Washington
Washington
Orlando
Jacksonville
Jacksonville
Miami
Hollywood
Jacksonville
Ft. Lauderdale
Coral Gables
Miami
Broward County
Orlando
Clearwater
Ft. Lauderdale
St. Petersburg
Athens
Atlanta
Atlanta
Atlanta
DeKalb County
24 Hr. Day
200
60
120
225
60
300
600
300
50
200
350
300
125
200
250
360
720
240
300
500
500
500
200
120
350
900
450
350
250
300
300
600
250
300
450
500
75
330
350
500
600
Date
Installed
1938
1941
1941
1942
1951
1951
1952
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1963
1966
1932
1955
1962
1942
1945
1949
1951
1952
1952
1954
1957
1960
1964
1964
1964
1966
1966
1939
1939
1951
1963
1964
-10-
-------
State
ILLINOIS
Installed Operating Capacity
3,960 tons/day
INDIANA
Installed Operating Capacity
835 tons/day
KANSAS
Installed Operating Capacity
35 tons/day
KENTUCKY
Installed Operating Capacity
1,350 tons/day
LOUISIANA
Installed Operating Capacity
1,940 tons/day
MARYLAND
Installed Operating Capacity
2,574 tons/day
MASSACHUSETTS
Installed Operating Capacity
4,690 tons/day
Aurora
Evanston
Cicero
Chicago
Chicago
Chicago
Skokie
Indianapolis
New Albany
Bloomington
Dodge City
Lexington
Louisville
Louisville
Lexington
Jefferson Parish
Jefferson Parish
Shreveport
New Orleans
New Orleans
New Orleans
Jefferson Parish
Baltimore
Salisbury
Baltimore
Montgomery County
Cambridge
Holyoke
Fall River
Brookline
Lawrence
Newton
Worcester
Framingham
New Bedford
Marblehead
Belmont
Boston
Waltham
Somerville
Wellesley
Dedham
Winchester
Capacity
Tons Per
24 Hr. Day
40
180
500
720
1200
1200
120
450
285
100
35
Date
Installed
1947
1955
1956
1956
1959
1963
1954
1959
1964
1965
200
750
250
150
90
100
350
400
400
200
400
600
124
800
1050
150
225
20
300
300
180
250
200
240
90
150
750
150
300
150
100
100
1957
1957
1965
1966
1948
1950
1951
1958
1962
1963
1964
1933
1933
1956
1965
1938
1947
1948
1952
1952
1954
1954
1955
1957
1958
1959
1959
1959
1960
1960
1961
1961
-11-
-------
State
MASSACHUSETTS (cont.)
Installed Operating Capacity
4,690 tons/day
MICHIGAN
Installed Operating Capacity
3,550 tons/day
MINNESOTA
Installed Operating Capacity
225 tons/day
MISSISSIPPI
Installed Operating Capacity
144 tons/day
MISSOURI
Installed Operating Capacity
1,000 tons/day
NEVADA
Installed Operating Capacity
100 tons/day
NEW HAMPSHIRE
Installed Operating Capacity
125 tons/day
NEW JERSEY
Installed Operating Capacity
1,424 tons/day
NEW YORK
Installed Operating Capacity
21,042 tons/day
Salem
Watertown
Lowell
Weymouth
Hamtramck
Detroit
Detroit
Detroit
Detroit
Garden City
River Rouge
Trenton
S.E. Oakland County
Central Wayne County
Ecorse
Minneapolis
Picayune
St. Louis
St. Louis
Las Vegas
Manchester
Hamilton Township
Hackensack
Red Bank
Spring Lake
Perth Amboy
Atlantic City
Princeton
Jersey City
Ewing
Buffalo
Elmira
Middletown
New Rochelle
-12-
Capacity
Tons Per
24 Hr. Day
235
100
400
300
200
600
600
400
400
10
50
100
600
500
90
225
144
500
500
100
125
100
100
60
30
90
94
100
600
250
400
100
50
150
Date
Installed
1962
1963
1964
1965
1957
1958
1958
1958
1958
1960
1961
1963
1963
1964
1954
1939
1966
1950
1958
1937
1925
1927
1930
1930
1930
1931
1954
1957
1965
1927
1929
1929
1929
-------
State
NEW YORK (cont.)
Installed Operating Capacity
21,042 tons/day
Schenectady
Glen Cove
Larchmont
New Rochelle
New York
Babylon
Cheektowaga N.W.
Amsterdam
Corning
Tonawanda
Lackawana
Mount Vernon
West Seneca
Tonawanda
North Tonawanda
Port Chester
Yonkers
Hempstead
Long Beach
Harrison
New York
Buffalo
New York
Huntington
Rochester
Babylon
Binghamton
Niagara Falls
Rochester
White Plains
New York
Oyster Bay
Tonawanda
Huntington
New York
New York
Rye
Scarsdale
Freeport
New York
East Rochester
New York
Valley Stream
Garden City
Beacon
Canajoharie
Hempstead
Huntington
Newburg
Oyster Bay
Rampo
Plainview
-13-
Capacity
Tons Per
24 Hr. Day
165
100
120
250
2840
90
150
120
80
90
100
600
60
90
72
120
450
700
200
150
1000
300
1000
150
450
300
300
240
450
400
660
500
80
150
1000
1000
150
150
150
1000
200
1000
200
175
100
50
650
150
240
500
200
900
Date
Installed
1932
1938
1939
1939
Prior to 1945
1946
1946
1947
1947
1948
1949
1949
1949
1950
1951
1951
1951
1952
1952
1953
1953
1954
1954
1955
1955
1956
1956
1956
1956
1956
1957
1957
1957
1958
1959
1959
1959
1959
1960
1961
1962
1962
1962
1963
1964
1964
1965
1965
1965
1965
1965
1966
-------
State
Capacity
Tons Per Date
24 Hr. Day Installed
OHIO
Installed Operating Capacity
4,840 tons/day
Cincinnati
Cleveland
Dayton
Youngstown
Barberton
Cleveland Heights
Lakewood
Cincinnati
South Euclid
Maple Heights
Euclid
Parma
Cleveland
Sharonville
Norwood
Cincinnati
400
900
200
300
65
150
100
500
100
150
300
225
500
300
150
500
1933
1936
1940
1945
1948
1948
1951
1954
1954
1955
1956
1957
1961
1961
1961
1965
OREGON
Installed Operating Capacity
60 tons/day
PENNSYLVANIA
Installed Operating Capacity
6,325 tons/day
RHODE ISLAND
Installed Operating Capacity
865 tons/day
Portland
Johnstown
Allentown
Erie
Lower Merion
Philadelphia
Pittsburgh
Meadville
West Mifflen
Ambridge
Philadelphia
Philadelphia
Bloomsburg
Red Lion
Philadelphia
Abington
Philadelphia
Philadelphia
Philadelphia
Cheltenham
Whitemarsh
Bradford
Delaware County
Philadelphia
Delaware County
Delaware County
Penn Hills
Newport
Warwick
Providence
60
55
150+
225+
80+
600
400
80
40+
150
200
300
60
60
300
200+
250
300
600
100
300
200
300+
600
300+
300+
175
100
45
160
1932
1920
1929
1930
1938
1938
1939
1949
1949
1950
1950
1950
1952
1954
1954
1955
1955
1955
1956
1958
1959
1960
1960
1960
1961
1962
1962
1937
1946
1948
-14-
-------
State
RHODE ISLAND (cont.)
Installed Operating Capacity
865 tons/day
TEXAS
Installed Operating Capacity
924 tons/day
UTAH
Installed Operating Capacity
300 tons/day
VIRGINIA
Installed Operating Capacity
1,710 tons/day
WEST VIRGINIA
Installed Operating Capacity
300 tons/day
WISCONSIN
Installed Operating Capacity
2,625 tons/day
Woonsocket
Pawtucket
Laredo
Houston
Houston
Houston
Amarillo
Ogden
Norfolk
Arlington County
Alexandria
Arlington County
Portsmouth
Roanoke
Charleston
Racine
Oshkosh
Whitefish Bay
Kenosha
Green Bay
Fond du Lac
Kenosha
Milwaukee
Milwaukee
Racine
West Allis
Racine
Wauwatosa
De Pere
Nekoosa
Sheboygan
Port Washington
De Pere
Green Bay
Capacity
Tons Per
24 Hr. Day
160
400
24
200
200
200
300
300
360
300
200
300
350
200
300
120
100
40
120
60
90
120
300
300
60
100
60
105
75
60
240
75
150
450
Date
Installed
1960
1964
1925
1947
1949
1954
1966
1966
1946
1949
1954
1955
1963
1964
1964
1929
1929
1929
1936
1946
1950
1951
1952
1954
1954
1954
1958
1959
1961
1963
1964
1965
1966
1966
TOTAL U. S.
74,578 tons/day
-15-
-------
TABLE 4
DISTRIBUTION
State
Connecticut
District of Columbia
Florida
Georgia
Illinois
Indiana
Kansas
Kentucky
Louisiana
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Nevada
New Hampshire
New Jersey
New York
Ohio
Oregon
Pennsylvania
Rhode Island
Texas
Utah
Virginia
West Virginia
Wisconsin
OF INCINERATORS OPERATING IN 1966
Number of
Number of County
Towns Incinerators
16
1
9 1
3
5
3
1
2
2 1
2 1
21
7 1
1
1
1
1
1
9
40
13
1
17 1
5
3
1
5
1
13
Total
185
Number of
Plants
19
3
14
5
7
3
1
4
7
4
21
11
1
1
2
1
1
9
60
16
1
26
5
5
1
6
1
19
254
-16-
-------
TABLE 5 (a)
INSTALLED INCINERATOR CAPACITY IN THE UNITED STATES
OPERATING IN 1966
Year
1950
1960
1966
Number of
Incinerators
90
205
254
Total
Capacity
22,932
57,044
74,578
TABLE 5 (b)
AVERAGE SIZE OF INCINERATORS
CONTINUING TO OPERATE IN 1966
Year Installed
Prior to 1950
1950-1959
1960-1966
Total
Number
254
Average Size
Max, Size
Installed*
74
102
78
Tons /Day
15,252
34,022
25,304
Tons /Day
206
334
324
Tons /Day
900
1,200
1,200
74,578
* This is a breakdown of the 254 incinerators installed prior to 1967
that are still in operation in 1966.
-17-
-------
TABLE 6
COMPOSTING PLANTS IN OPERATION IN THE UNITED STATES
JUNE 1967
Altoona, Pennsylvania
St. Petersburg, Florida
Houston, Texas (1)
Mobile, Alabama
Boulder, Colorado (2)
Tons/Day
20 to 45
105
300
200
100
725 to 745 tons/day of refuse
(1) In June, 1967 Houston was operating one plant and another
had been constructed (400 tons per day) which was not
operating due to contract problems.
(2) The plant had been shut down temporarily due to bad
weather when the city was contacted.
-18-
-------
GEOGRAPHIC DISTRIBUTION OF WASTE REDUCTION
FACILITIES IN OPERATION - 1966
Waste Reduction Facilities
Expressed In Tons Capacity
Per 24 Hour Day
Figure 1
-------
vacant land might choose to use the more expensive disposal method.
The variables used were:
Variable
1. Population
2.
3.
Population density
(people per square
mile)
Value added by manu-
facturer
4. Total Sales
5. Year
Why Selected
More people means more
waste
Best variable with data
available
Manufacturing is a
source of solid waste
Economic activity
affects amount of
solid waste
Per capita solid wastes
and other factors
change with time
The Variable is an
Indicator of the
Following Factors
Municipal waste
generation
Vacant land
Industrial waste
generation
Total waste
generation
Growth in total
waste generation
per capita and
other factors
which change with
time
Other variables such as urban population, urban land, urban population
density, state land area, and a variable measuring the competition
between cities for land were investigated. However, these variables
were found to have either negligible correlations with solid waste
reduction capacity or they duplicated the correlation found with the
five variables used in the final model.
In the development of the model, the variables mentioned above were
combined to provide a more meaningful explanation of solid waste
reduction capacity. For example, population density as a measure of
vacant land would indicate when waste reduction equipment should be
installed, but would not also indicate the size of this equipment
necessarily. Population as a measure of the waste produced does indicate
the size of equipment when it is necessary. These two factors combined,
therefore, are a better factor than both taken independently. Another,
but less obvious interaction was discovered in value added by manufacture
and total sales. Consequently, these factors, in addition to being
considered independently, were combined to form a new factor which allows
for the interaction. Data for the independent variables was obtained. to
Table 7 shows the correlation between dependent and independent variables.
For example, the intersection of row 2 and column 4 contains the
correlation coefficient of variables 2 and 4. Likewise, the number at
the intersection of row 4 and column 2 is the same number because it is
-20-
-------
a measure of the correlation of the same two variables 4 and 2. There-
fore, the matrix shown in Table 7 is symmetrical about the diagonal
denoted by the unity coefficients. If variable 2 was plotted against
variable 4, it would have a correlation coefficient of .77. However,
it should be noted that when several variables are used, multiple
regression analysis can result in a regression coefficient larger than
any of the individual correlation coefficients shown in Table 7.
-21-
-------
TABLE 7
i
to
to
I
NATTDNAT. MATfTF.HATJflAT. MODE!- TlffflRRTJlTTON MATRIX
Variable 1*
1 1.00
2 .91
3 .84
4 .81
5 .80
6 .72
7 .78
8 .81
9 .71
10 .09
Y .76
* Numbers
2
.91
1.00
.99
.77
.80
.71
.86
.80
.86
.09
.91
refer to
X1 = Population x
1 Xx-5
2 Xjl-5
3 XT2
3
.84
.99
1.00
.72
.77
.67
.86
.76
.90
.09
.93
4
.81
.77
.72
1.00
.99 1
.90
.93
.99
.83
.25
.72
the following list of
Population
density x
5
.80
.80
.77
.99
.00
.86
.97
.97
.90
.25
.77
6
.72
.71
.67
.90
.86
1.00
.84
.94
.74
.24
.70
7
.78
.86
.86
.93
.97
.84
1.00
.95
.97
.22
.87
8
.81
.80
.76
.99
.97
.94
.95
1.00
.86
.24
.76
9
.71
.86
.90
.83
.90
.74
.97
.86
1.00
.21
.90
10
.09
.09
.09
.25
.25
.24
.22
.24
.21
1.00
.24
Y
.76
.91
.93
.72
.77
.70
.87
.76
.90
.24
1.00
Variable
1
2
3
4
5
6
7
8
9
10
Y
variables:
10~6
6
7
X = Total
3
V5
s
Sales $
x 10 6
10
Y =
X = Year
Tons of
capacity
24 hour
installed
per
day.
4 X? = Value added by manufacturer $ x 10
-6
8 X
-------
C. PROJECTIONS OF NATIONAL INSTALLED WASTE REDUCTION CAPACITY T0_1975
Equations 1 and 2 can be used to predict the solid waste reduction
capacity of the nation by state in 1975. The complex model, Equation 1,
used five independent variables and achieved a multiple correlation
coefficient of .98 with a standard error of estimate of 899 tons. The
correlation of .98 means that these variables explain (.98 x .98)
96 percent of the variability in the installed capacities of the states.
Although the simplified model, Equation 2, used only two independent
variables, a multiple correlation coefficient of .96 with a standard
error of 1,165 tons was achieved. This simpler model accounts for
(.96 x .96) 92 percent of the variability of the installed capacities
of the states.
COMPLEX EQUATION FOR NATIONAL MODEL
Eq. 1) Y = 145138 + 143.585X]/5 - .0932X11'5 - .OOlSXj^ + 7374X2
- 1284X21-5 + 9406X3'5 + 464X4 - 9318X4'5 - 8.423X41'5 + 69.855X5
WHERE:
Y = tons of installed capacity per 24 hour day
X]_ = population x population density x 10~6 = (people) 2 x 10~°
sq. mile
X2 = value added by manufacture $ x 10
X3 = total sales $ x 10~9
X4 = X2 X-}
X5 = year
Standard Error of Estimate = 899 tons
Multiple Correlation R = .98
Number of Observations = 54
SIMPLIFIED EQUATION FOR NATIONAL MODEL
T" _ C £ V _ I 1 -7 r f\£\T 'J
Eq. 2) Y = -JSgSXiKr - 5.6X! + 275.96X]/5 + S.eXKT^Xi + 80.54X5
WHERE:
Y = tons of installed capacity per 24 hour day
X-|_ = population x population density x 10~6
X5 = year
Standard Error of Estimate = 1,165 tons
Multiple Correlation R = .96
Number of Observations = 54
-23-
-------
Figure 2 is a graphical representation of the simplified equation for
1950, 1960, 1966 and 1975. An inspection of the data indicated that
the regression line fits the data well at high values of X^. The
equation has a smooth transition from these high values to zero, and
because of this smooth transition an Xj_ value of 400 and below does
not fit the data well. Consequently, the equation was not used to
predict installed capacity in states whose X]_ value was below 400 in
1975.
The simplified rather than complex equation ras employed as the basis
for projection of installed waste reduction capacity in 1975 because
projections of some of the variables used in the complex model were
not available for 1975.
A differential shift method (Equation 3, Table 8) was used to project
installed capacity by state to 1975. Some states' waste reduction
capacity is greater and others less than anticipated by the model
(Equation 2), and it was assumed that the relative position of each
state to the curve would be the same in 1975. For example, if a state
had a waste reduction capacity greater than that which the model
predicts for 1966, it would have a waste reduction capacity greater
than the model predicts in 1975.
Three values are presented in Table 8 for the installed waste reduction
capacity in 1975. The first two values are presented in tabular form
for each state. These results were obtained from the substitution of
the highest and lowest values of the Bureau of Census population
projections for each state in 1975 into Equation 3, given at the top
of Table 8. The resulting national installed capacity using the high
population figure yields 125.,000 tons per day, the low population
figure yields 107,000 tons per day. A straight line engineering
projection shown in Figure 3 yielded a value of 104,550 tons per day.
Two exceptions to the above method were the projections made for
California and New Jersey. California in recent years has shut down
all operating waste reduction plants because these plants did not have
air pollution control equipment to meet requirements of the state.
With the improvement of air pollution control devices, California might
start reinstalling waste reduction plants, and consequently, the
highest projection of the model is presented. It is also conceivable
that the present trend of zero waste reduction plants will continue and,
consequently, the low projection for California is zero.
The mathematical model was not used to predict the installed waste
reduction capacity in New Jersey in 1975 due to the land characteristics
of the state. New Jersey has more low, flat, marshy land in relation to
its total land area than other states. This land is ideally suited for
land fill operations. Also, this land is in close proximity to the
larger cities and provides the most economic type of refuse disposal
available. However, New Jersey is both densely populated and has little
total land area two factors which would usually indicate the need for
waste reduction facilities.
-24-
-------
The values presented in Table 8 for New Jersey are engineering estimates.
As long as the land can continue to be used for this purpose, large
increases in waste reduction capacity cannot be expected. It is
interesting to note that if New Jersey was similar to other states, it
would have from 16,500 to 24,000 tons per day installed in 1975 an
unrealistic expectation in light of their present solid waste disposal
practices.
-25-
-------
100,000
90,000
80,000
70,000
60,000
50,000
40,000
30,000
20,000
a.
<
u
Q£
O
Q
UJ
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
900
800
700
600
500
400
300
200
TONS OF INSTALLED WASTE REDUCTION CAPACITY
DETERMINED FROM NATIONAL MATHEMATICAL MODEL
1975'
\3T
t
2,000 4,000 6,000
POP. X (POP. DENSITY) (PEOPLE)2 X 10~6
8,000
10,000
SO. MILE
Figure 2
-26-
-------
TABLE 8
INSTALLED WASTE REDUCTION CAPACITY FOR 1975
BASED ON PROJECTIONS OF NATIONAL WASTE REDUCTION MODEL
Eq. 3)
= 733.50 - 5.60(X75 - X66) + 275.96(X75
2
5 - X66'5)
8.6 x 10
- X66 >
Y
66
WHERE:
NOTE:
Y = installed capacity
X = population x population density x 10~°
Subscripts define year to which variables applied
Equation applies only when X>400
When X<400, Y75 assumed = Y66
Y
TONS/DAY
Alabama
Arkansas
Arizona
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
HIGH
1,250
0
0
7,300
0
6,300
0
6,350
2,900
0
5,350
1,650
0
35
2,300
2,950
0
3,650
8,800
4,400
LOW
1,150
0
0
0
0
6,100
0
6,250
2,800
0
5,100
1,650
0
35
2,200
2,900
0
3,550
7,500
4,300
X
POP. x P.O. x 10"
HIGH
305.1
89.3
46.2
3,783.4
5.7
2,281.3
194.4
1,239.4
435.0
7.3
2,617.7
852.5
157.9
70.3
302.2
393.9
3«.6
1,869.6
4,640.3
1,537.0
LOW
280.8
81.4
38.8
3,351.6
5.2
2,101.9
177.0
1,050.6
402.8
7.0
2,454.5
794.5
141.6
64.5
270.2
366.3
34.6
1,703.6
4,311.2
1,405.6
-27-
-------
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode' Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Y
TONS /DAY
HIGH
225
144
1,850
0
0
100
125
2,250
0
39,300
900
0
6,900
0
60
8,000
1,700
1,000
0
1,000
1,900
300
0
2,650
0
300
3,550
0
LOW
225
144
1,800
0
0
100
125
2,125
0
33,200
850
0
6,350
0
60
7,350
1,600
950
0
900
1,850
300
0
2,650
0
300
3,500
0
125,489 107,914
Engineering Projection - 104,550 tons
x _6
POP, x P.P. x 10
HIGH LOW
209.2 193.0
150.2 134.4
340.6 313.5
4.1 3.9
34.0 30.8
2.1 2.0
66.8 61.3
8,665.5 7,948.5
14.8 12.9
8,624,2 92.9
630.7 576.3
7.1 6.0
3,405.9 3,190.4
105.6 96.1
47.5 43.8
3,483.6 3,210.9
921.8 849.4
286.6 268.3
7.9 6.7
444.8 411.4
583.3 537.3
19.1 17.1
23.6 22.2
665.8 624.1
181.7 169.2
142.8 123.0
414.7 381.0
1.6 1.2
-28-
-------
INSTALLED INCINERATORS IN OPERATION - U. S.
CO
I
o
Z
O
u
<
0-
<
(J
LU
z
U
z
I/)
z
no
100
90
80
70
60
50
40
30
20
10
1950 1955
104,550 tons
projected for 1975
(Engineering
Projection)
I960 1965
YEAR
Figure 3
-29-
1970 1975
-------
SECTION III
CONNECTICUT MODELS
A. MODEL CONCEPT
The Connecticut waste reduction models are shown in relation to other
planning models in Figure 4. The chronological development of these
models is illustrated in Figure 4. Model 1 can be any national
projection of economic activity. The one shown in Figure 4 was
developed by the National Planning Association. Models 2 and 3, shown
in Figure 4, were developed by the state of Connecticut for its
planning needs. These models can be developed by other states for
highway planning and other municipal planning activites. The
Connecticut solid waste models, Model 4, were developed by Combustion
Engineering during the present study.
Connecticut's land usage study (Model 3, Figure 4) complied with the
Federal regulation that all towns of over 5,000 people in a state must
undertake a land usage study in order that the state be eligible for
the 90 percent Federal aid in road building projects. The use of the
Connecticut land usage study as a basis for developing the Connecticut
waste reduction model can serve as an example for other states wishing
to model their own solid waste reduction needs. The data necessary for
the variables used in the state's model should readily be available
from its own land usage study.
Model 3, Connecticut's land usage study , distributed the state total
of several economic variables such as population and manufacturing
employment to each of the 169 Connecticut towns. This was done through
the use of a method called differential shift analysis. The change in
an economic variable of a sub-region is assumed to consist of two
factors. The first factor, called the proportional shift, allows for
the change of this variable as a percentage of the change of the entire
state. The second factor allows for the differential shift between the
sub-region and the state. That is, this second factor allows for the
difference in the growth rates of the entire state and the individual
towns.
The Connecticut land use model was formulated as a set of simultaneous
equations, each equation describing one sector of the economy. The
equations mathematically formulated the interplay between transportation
facilities in and leading to a town and the presence of people in the
town. The tendency of people to settle near transportatior facilities
and the tendency of highways to be built near people were described
mathematically. These equations were solved with a computer and the
results were used by Combustion Engineering as inputs to the waste
reduction and waste production models described in detail in this report-,
-30-
-------
THE INFORMATION SOURCES OF THE
CONNECTICUT REDUCTION CAPACITY MODEL
MODEL 1
MODEL 2
MODEL 3
MODEL 4
National Planning Association c
Reports on Industrial Employment-
i
Future Employment by S.l.C. Code
Connecticut "Socio-Economic Growth Model"
by Connecticut Interregional Planning Program
10
Regression analysis on past trends and an economic input-
output model for Connecticut were used to predict population
and employment levels and outputs to the industrial and
service sectors to the year 2000.
Employment and Population for
Connecticut in I960, 1970, 1980,
1990, 2000.
"A Model for Allocating Economic
-i -i
Activities into Sub-Areas in a State"11
Prepared for the Connecticut Interregional Planning Pro-
gram (CIPP) by Alan M. Voorhees & Associates, Inc.
A mathematical model ("Transportation Study") developed
by linear regression techniques allocated Connecticut's
residential and industrial population into each of the
169 towns for 1960, 1970, 1980, 1990, and 2000.
i
Vacant Land, Population and
Employment (manufacturing, retail,
service and others) by towns for
1960, 1970, 1980, 1990, and 2000.
Connecticut Solid Waste Models (This Report)
The waste generation per capita and per employee by S.l.C.
Code were determined from the municipal and industrial
solid waste inventories. By means of linear regression, the
waste reduction capacity of Connecticut towns was correlated
with the data of the CIPP study. The resulting mathematical
model was used to project installed waste reduction capacity
by county to 1975. Municipal and industrial waste production
were also estimated.
Municipal Waste, Industrial
Waste and Incineration Capacity
in 1975.
Figure 4
-31-
-------
B. DESCRIPTION OF VARIABLES
The data for one of the dependent variables, tons of installed capacity
per day per town, comes from Table 3, The data for the other dependent
variable, tons of solid waste reduced per week per town, comes from
Reference 13. Connecticut's incinerators are not utilized to capacity.
For example, the town of Greenwich with a rated capacity of 450 tons
per day or 3,150 tons per week reduces only 720 tons of solid waste per
week. The data on the utilization of Connecticut incinerators was
incorporated into the Connecticut utilization model. Typical utili-
zation data is provided in Table 9. Using this utilization data, a new
variable, Y", tons of solid waste reduced per week, was developed.
This aew dependent variable was used with the variables of the
Connecticut capacity model to form the Connecticut utilization model.
The independent variables for these models are similar to the variables
described previously. It was again assumed that solid waste reduction
capacity was primarily dependent upon two factors: (1) amount of refuse
generated and (2) amount of land available for land fill.
The variables used in the Connecticut models were:
Variable
1. Population
Total possible popu-
lation (based on
zoning laws)
Manufacturing
employment
Total possible
manufacturing
employment
Vacant land
Why Selected
More people means
more waste
Measures residential
land available
Industry is a source
of solid waste and
also indicates general
economic activity
which is associated
with solid waste
production
Measures industrial
land available
The Variable is an
Indication of the
Following Factor
Municipal waste
generation
Vacant land
Industrial waste
generation
Vacant land
Vacant land
The data for these independent variables was found in References 10 and
11. Table 9 presents a typical summary of county data.
-32-
-------
TABLE
TYPICAL SUMMARY OF COUNTY DATA 1966
i
uo
00
Town
Bethel
Bridgeport
Brookfield
Danbury
Darien
Easten
Fairfield
Greenwich
Monroe
New Canaan
New Fairfield
Newton
Norwalk
Redding
Ridgefield
Shelton
Sherman
Stamford
Stratford
Trumbull
Weston
Westport
Wilton
OBTAINED ERQML r-OMMKCT-TCITT TRANSPORTATION STUDY
FAIRFIEID COUNTY
Population
9,731
157,685
6,664
46,200
21,411
4,728
50,481
57,885
9,241
19,440
4,578
12,639
71,856
5,320
13,500
20,142
1,029
104,643
50,195
26,322
5,507
27,656
11,833
Total
Possible
Population
28,117
158,309
32,894
103,902
27,395
11,453
71,992
68,279
33,987
25,682
26,308
60,151
96,618
16,242
42,547
58,483
17,557
123,056
60,408
47,297
11,524
35,561
21,389
Mfg.
Population
873
33,684
342
9,106
215
0
2,852
4,573
536
226
5
2,344
14,245
370
206
3,910
3
17,584
2,660
305
0
391
575
Total Pos-
sible Mfg_.
Population.
1,795
36,871
7,932
20,924
215
0
4,950
4,573
829
255
5
5,393
25,622
424
2,568
8,414
3
19,658
18,487
1,546
0
391
2,534
738,686
1,179,151
95,005
163,389
Tons/Day
Installed
0
500
0
0
60
0
0
450
0
50
0
M
\j
360
0
0
0
0
350
240
0
C
0
0
2,010
Tons/Week
Reduced
0
1,662.5
0
0
200.0
0
0
720.0
0
117.0
0
0
1,055.0
0
0
0
0
1,380.0
800.0
0
0
0
0
5,934.5
-------
Total possible population was generated by the land allocation model
from a consideration of the town zoning laws and the suitability of this
land to support population on the basis of slope and soil characteristics.
Total possible manufacturing employment was similarly generated from
land zoned for industrial purposes.
In the development of the models, the variables mentioned above were
combined to provide a more meaningful explanation of solid waste
reduction capacity. For example, the ratio of population to total
possible population saturation would indicate when waste reduction
equipment should be installed. However, it would not also indicate the
size of this equipment necessary. Population as a measure of the waste
produced does indicate the size of equipment when it is necessary. These
two factors combined, therefore, are a better factor than both taken
independently. Manufacturing employment and total possible manufacturing
were similarly combined. Since some towns are completely residential and
total possible manufacturing is zero, a "one" was added in the denominator
to prevent the variable from becoming indeterminate.
As shown in Tables 10 and 11, land in Connecticut is characterized by
class and is described by land characteristics by the Connecticut
Interregional Planning Association. Land zoning is prescribed by town
governments. The land characteristics depend upon the soil and slope of
the terrain. It may be possible to develop a relationship between the
number of solid waste disposal sites and the type of land on which they
are built.. However, the data summarized in Tables 12 and 13 indicate
that Connecticut towns have in the past and can in the future use any
type of land for waste disposal sites. For this reason, the variable
"vacant land" included all the unused land in a town rather than land of
special soil, slope, or zone characteristics.
Data such as that shown in Table 14 was available for all Connecticut
towns for 1960, but not for 1966 and 1975. To determine the non-industrial
vacant land in 1966 and 1975, the 1960 non-industrial vacant land figure
was changed by an amount proportional to the change in population for the
town. That is:
(Vacant Land)55 - (Vacant Land)gg _
(Vacant Land)gQ
Populationgg - Populationgg
(Total Possible Population)
and
(Vacant Land)75 - (Vacant Land)50
(Vacant Land)gg
Populationy^ - Populationgg
(Total Possible Population)
-34-
-------
TABLE 10
12
ZONE CLASSES IN CONECTICUT
Zone
Ind.
1
2
3
4
Spec.
Com.
Industrial
Residential lots up to 4,999 square feet
Residential lots 5,000 square feet to 19,999 square feet
Residential lots 20,000 square feet to 39,999 square feet
Residential lots 40,000 square feet and over
Specially zoned for such purposes as recreation and flood
plain zoning
Commercial
TABLE 11 (a)13
LAND CLASSES IN CONNECTICUT
Soil Class
Soil Class
Soil Class
Soil Class
#1
#2
#3
#4
Excellent for building purposes
Good - Fair for building purposes
Poor for building purposes
Very Poor for building purposes
Soil Class #1A is a modification of Soil Class #1
TABLE 11 (tO
Soil Class 4
3
2
1A
1
5
4
2
1
i
5
4
2
2
5
4
2
3
5
4
2
4
5
5
2
5
0% 5% 10% 15% 20% 20%+
-35-
-------
TAB LE_12
NUMBER OF WASTE DISPOSAL_SITES_BY
ZONE FOR CONNECTICUT IN 1966
Zone Number of Sites
Industrial 35
1 0
2 13
3 17
4 67
Special 7
Commercial 4_
143
TABLE 13
NUMBER OF WASTE_DISP_OSAL_SLTES BY
LAND CLAS"S~FO'R CONNECTICUT
Land Class Number of Sites
1 29
2 32
3 5
4 27
5 _50
143
-36-
-------
TABLE 14
10
Zone
Residential 1
Residential 2
Residential 3
Residential 4
Commercial
Industrial
Other
Total
TYPICAL SUMMARY OF
Bethel -
Vacant Land
LAND
1 23
0 00
207 68 8
269 515 67
1,032 1,083 608
18 21 0
96 15 14
0 00
VACANT LAND DATA
1960
in Acres
CLASS
4 5
0 0
95 184
165 397
1,731 2S002
0 6
65 246
0 0
Total
o
562
1,413
6,456
45
436
0
1,622 1,702 697 2,056 2,835
8,912
-37-
-------
to determine the amount of industrial vacant land for 1960 and 19/5.
' ..3 manufacturing employment figures were used in a manner similar to
that for non-industrial land.
Table 15 shows the relationship among the dependent and independent
variables of the Connecticut capacity model. Table 16 shows the
relationship among the dependent and independent variables of the
Connecticut utilization model.
C. PROJECTIONS OF INSTALLED WASTE REDUCTION CAPACITY TO 1975
Equations 4 and 5 model the solid waste reduction capacity of
Connecticut by town. One hundred sixty-nine observations were used to
generate each equation. The first equation uses three independent
variables and achieves a multiple correlation coeificient of .95 with
a standard error of 34.3 tons per day. Thus, 90 percent ( 95 x .95) of
the variability of the installed capacities of Connecticut towns is
accounted for by this model.
Although the simplified model uses only one independent variable, it
does almost as well as the complex model. A multiple correlation
coefficient of .94 is achieved with a standard error of 37.6 tons per
day. Thus, this simple model accounts for 88 percent (.,94 x .94) of
the variability of the installed capacities of Connecticut towns.
Table 17 presents a compilation of the Connecticut model 1975
projections in terms of tonnage per county rather than tonnage per town.
This is due to the difficulty of accounting for the political decisions
involved in the installation of solid waste reduction equipment. For
example, one of two towns, each needing 30 tons of waste reduction
capacity, may decide to build a 60 ton unit while the other town may
continue with land fill disposal. Neither town should actually build
the needed 30 ton unit because about 60 tons is the size of the smallest
economically feasible size of waste reduction equipment. Thus, the
difficulty of quantifying political decisions and the economic
limitations on waste reduction equipment size resulted in the decision
to express the data on a per county basis. The countv data was obtained
by summing the town data for each county. Typical county data is shown
in Table 9 for the county of Fairfield. The 68 percent confidence level
for both models is approximately ^200 tons per day for the state.
Figure 5 represents the relationship between Y* and Xg. The effect of
time, i.e. year, was not evaluated in this study, The relationship
consequently represents one time period (1966). To improve the
protective ability of this model with time, consideration should be made
of increases in per capita waste generation and the change in ratio of
industrial to municipal waste handled by Connecticut towns. For example,
the values of Y would have to increase by about 25 percent in 1975 over
the values indicated to account for a 2.5 percent compounded annual
increase in waste generation.
It will be noticed that the graph levels off at 600 tons per day because
a Connecticut town with a value of Xg that corresponds to a Y equal to
-38-
-------
TABLE 15
CONNECTICUT MATHEMATICAL
CAPACITY .MODEL-CORRELATION MATRIX
Variable
1
2
3
4
i 5
i
6
7
8
Y l
1*
1.00
.82
.74
.81
.67
.40
.39
.36
.82
2
.82
1.00
.99
.85
.83
.07
.10
.11
.90
3
.74
.99
1.00
.80
.83
.01
.03
.05
.86
.81
.85
.80
1.00
.92
.18
.19
.18
.81
5
.67
.83
.83
.92
1.00
.03
.04
.05
.72
6
.40
.07
.01
.18
.03
1.00
.98
.93
.12
.39
.10
.03
.19
.04
.98
1.00
,98
.16
8
.36
.11
.05
.Id
.05
.93
.98
1.00
.19
Y'
.82
.90
.86
.81
.72
.12
.16
.19
1.00
Variable
1
2
3
4
5
6
7
8
Y'
Numbers refer to the following list of variables
X6 -
Population"
Total Possible Population
4 XT = (Manufacturing Employment)
Total Possible Manufacturing Employment "*"-*-
X6
2 X,
.5
1.5
6 X = Vacant Land x
1/2
3 X6'
7 X,
1.5
8V =-
X8
Y ' = Tons of installed capacity, per 24 hour day
-------
TABLE 16
o
I
CONNECTICUT MATHEMATICAL - UTILIZATION
MODEL
CORRELATION MATRIX
Variable
1
2
3
4
5
6
7
8
9
Y"
1* 2 3 4
1.00 .97 .93
.97 1.00 .99
.93 .99 1.00
.85 .80 .84 1.
.80 .83 .83
.20 .07 .01
.22 .10 .10
.22 .11 .05
.83 .84 .82
.94 .94 .90
* Numbers refer to the following list of
1 X6 =
(Total
2 x,. "
3 X62
X7 =
(Total
9 o
Population 10
Possible Population)
(Manufacturing Population)
5
85 .20
86 .83
84 .83
00 .98
98 1.00
09 .03
10 .04
10 .05
93 .90
85 .79
variables
2
Possible Manufacturing Population)
6
.20
.07
.01
.09
.03
1.00
.98
.93
.05
.10
5V
7
6 X8
7 X8
8v
-"Q
O
Xn
7
.22
.10
.10
.10
.04
.98
1.00
.98
.05
.13
2
= Vacant
1.5
2
8
.22
.11
.05
.10
.05
.93
.98
1.00
.06
.15
Land x
= (Manufacturing
9
.83
.84
.82
.93
.90
.05
.05
.06
1,00
.84
"1 / O
CX6)1/2
Population)
y" Vai
.94
.94
.90
.85
.79
.10
.13
.15
.84
1.00
x Population
riabl
1
2
3
4
5
6
7
8
9
Y"
4 X-
1.5
9 X,
(Total Possible Population)
1.5
)
= Tons of solid waste reduced per week per town
-------
Eq. 4)
WHERE:
COMPLEX CONNECTICUT CAPACITY 'MODEL
Y' =-21.8095 - 13.629X6'5 + 1.35389X61'5 - .0759122X62 + 6.00175
x 10~3x7 - 3.053 x 10~7X72 + .0116033X8 - 9.84902
x 10~5Xo1'5 + 2.06190 x 10 7X82
Y' =< tons installed capacity per day per town
X7 =
population2 (town) x ._1_0_"'_~J
total possible population (town)
manufacturing employment_ (town)
total possible manufacturing employment (town) + 1
__
/ 7 3
= vacant land (acres-town) / population _(town) x^.10
f total possible population (town)
Correlation Coefficient R = .95
Standard Error of Estimate = 34.3 tons
per day
Number of Observations = 169
SIMPLIFIED CONNECTICUT CAPACITY MODEL
Eq. 5)
WHERE:
Y' = 3.13757 - 6.5456X6 + 2.3710X61'5 - .123466X62
Y' = tons installed capacity per day per town
Xg = population (town) x 10~3
total possible population (town)
Correlation Coefficient R = .94
Standard Error of Estimate = 37.6 tons
per day
Number of Observations = 169
-41-
-------
TONS/DAY OF INSTALLED INCINERATOR CAPACITY DETERMINED FROM CONNECTICUT MODEL
ro
i
Points of Zero Incinerator
/Capacity fall up to this point
20
POPULATION X (
TOTAL POSSIBLE POPULATION'
Figure 5
-------
TABLE 17
CONNECTICUT SOLID WASTE REDUCTION CAPACITY BY COUNTY
TONS
County
Fairfield
Hartford
Litchfieli
Middlesex
New Haven
New London
Tolland
Windham
OF INSTALLED CAPACITY
1966
Actual
2,010
1,450
0
0
1,380
120
0
0
PER 24 HOUR DAY
1975
E
-------
600 is probably saturated. That is, the population of the town is about
equal to the total possible population. Thus, solid waste reduction
needs will probably increase due to increased waste per capita or due to
municipalities handling a larger share of the industrial solid waste
stream.
D. PROJECTIONS OF UTILIZED WASTE REDUCTION CAPACITYJTO 1975
Equations 5 and 6 model the utilized solid waste reduction of Connecticut
by town. One hundred sixty-nine observations were used to generate each
equation. The first equation uses four independent variables and
achieves a multiple correlation coefficient of .97 with a standard error
of 74.1 tons per week. Thus (.97 x C97) 94 percent of the variability
of the utilized capacities of Connecticut towns is accounted for by
this model. The correlation coefficient and standard error of the
utilization model as compared to the correlation coefficient (.95) and
standard error (34.3 tons per day) of the capacity model indicate that
the utilization model is the better model. The utilization model removes
one additional unknown from the models previously described. That is,
that a town can have 500 tons per day installed capacity and operate it
eight hours to provide the same burning as a 250 ton per day plant
operating sixteen hours a day.
The simplified utilization model does almost 'as well as the complex
model although only one independent variable was used, A multiple
correlation coefficient of .96 is achieved with a standard error of
85.9 tons per week. Thus this simple model accounts for (.96 x .96)
92 percent of the variability of the utilized capacities of Connecticut
towns.
Table 18 presents a compilation of the Connecticut utilization model
1975 projections in terms of tonnage per county. The county data was
obtained by summing the town data for each county. Typical county data
is shown in Table 9 for the county of Fairfield, The 68 percent
confidence level for both models is approximately d:l,100 tons per week
for the state.
E. MUNICIPAL AND INDUSTRIAL WASTE PRODUCTION FOR CONNECTICUT TO 1975
Tables 19 to 22 present the estimated 1965 and the projected 1975 values
of municipal and industrial wastes for Connecticut counties. The 1975
municipal waste figures were computed from the 1965 per capita waste
figures and the 2.5 percent compounded growth rate obtained from the
municipal inventory section of this report. The 1975 municipal per
capita waste figures were then multiplied by the 1975 population figures.
The table showing industrial wastes is taken from the industrial
inventory portion of this report. The calculations involved and the
method used for the 1975 industrial waste projections can also be found
in the industrial inventory section.
-44-
-------
COMPLEX CONNECTICUT
UTILIZATION MODEL
Eq. 6)
= 35.587 - 19.9571X6 + G.
'5 - .290490X6 + .400826
5 - .253287 x 10~5X72 + .016324Xg - .133483
x 10~3X01<5 + .271533 x 10"6Xo2 + .464890 x lO"^1'
o o y
WHERE:
Y" = tons of solid waste reduced per week per town
Xg = population (town) x 10~^
total possible population (town)
r~\
Xy = manufacturing employment (town)
Xc
total possible manufacturing employment (town) + 1
______ _
= vacant land (acres - town) / population (town) x 10"
total possible population (town)
= manufacturing population (town) x
population (town)
total possible population (town)
Correlation Coefficient = .97
Standard Error of Estimate = 74.1 tons
per week
Number of observations = 169
S IMPLI FI
UTI LI ZATION MODEL
Eq. 7)
Y" =* 13.400 - 21.9399X6 + 7.18692X61"5 - .359355X,
WHERE:
Y = tons of solid waste reduced per week per town
X6 =
r\
population (town)
total possible population (town)
Correlation Coefficient = .96
Standard Error of Estimate =85.9 tons
per week
Number of Observations = 169
-45-
-------
TABLE 18
CONNECTICUT SOLID WASTE REDUCTION
County
Fairfield
Hartford
Litchfield
Middlesex
New Haven
New London
Tolland
Windham
UTILIZED CAPACITY
Tons of
1966
Actual
5,934.5
4,631.5
0
0
3,070.5
240.0
0
0
OF COUNTY
Utilized Capacity
1975
Eq. (6)
6,559.5
5,765.0
0
0
4,972.7
430.6
0
0
Per Week
1975
Eq. (7)
7,201.6
5,731.4
0
0
5,230.7
484.8
0
0
TOTAL
13,876.5
17 ,727.1
18,648.5
-46-
-------
TONS/WEEK OF SOLID WASTE INCINERATED DETERMINED FROM CONNECTICUT UTILIZATION MODEL
2200
2000
Points of Zero Incinerator
Capacity fall up to this point
POPULATION X (
80 100
POPULATION
TOTAL POSSIBLE POPULATION
Figure 6
) X 10
-3
-------
TABLE 19
MUNICIPAL WASTE FOR DISPOSAL IN CONNECTICUT BY COUNTY FOR 1965
Pounds per Capita per Day
Residential 2.4
Bulky .3
Commercial** 1.4
4.1
** Commercial waste is 1.4 pounds per urban capita per day.
Connecticut population is about 80 percent urban and there-
fore a figure of 1.1 pounds per capita per day was used in
the calculations.
County
Fairfield
Hartford
Litchfield
Middlesex
New Haven
New London
Tolland
Windham
Population
(1965)
7305100
762,500
131,100
99,700
719,700
207,700
82,400
75,800
Residential
MPY**
630
662
114
87
625
180
72
66
Bulky
MPY**
80
84
14
11
79
23
9
8
Commercial
MPY**
293
306
53
40
289
83
33
30
Total
MPY**
1,003
1,052
181
138
993
286
114
104
TOTAL
2,809,000
2,436
308
1,127
3,871
** Million pounds per year
-48-
-------
TABLE 20
MUNICIPAL WASTE FOR DISPOSAL IN C
Residential
Bulky
Commercial
ONNECTICUT BY COUNTY FOR 1975
Lbs . /Capita/Day
3.07
.38
1.81**
5.26*
* Based on a compounded growth rate of 2.5 percent
per year.
** Commercial waste is 1.8 pounds per urban capita
per day.
Connecticut population is about 80 percent urban
and therefore a figure of 1.4 pounds per capita
per day was used in the calculations.
County
Fairfield
Hartford
Litchf ield
Middlesex
New Haven
New London
Tolland
Windham
Population Residential
(1975) MPY***-
861,910 965
901,120 1,012
157,129 171
149,791 168
846,323 950
260,803 292
112,432 126
93,454 105
Bulky Commercial
MPY*** MPY*** Total
121 453 1,539
126 474 1,612
22 83 276
21 79 268
H9 445 1,514
37 137 466
16 59 201
13 49 167
TOTAL
3,382,962
3,789
475
1,779
6,043
*** Million pounds per year
-49-
-------
TABLE 21
INDUSTRIAL WASTE FOR DISPOSAL IN CONNECTICUT
BY COUNTY FOR 1965
Total**
County
Fairfield
Hartford
Litchfield
Middlesex
New Haven
New London
Tolland
Windham
Manufacturing
Employment
105,153
129,670
16,519
11,856
95,677
36,145
3,221
15,013
Manufacturing
Solid Waste
(MPY)*
485
502
76
80
538
142
16
81
Total
Employment
251,318
363,291
36,570
35,354
275,334
75,873
17,731
24,906
Industrial
Solid Waste
(MPY) *
1,010
1,047
169
156
1,035
285
72
138
TOTAL
413,254
1,920
1,080,377
3,912
* Million Pounds Per Year
** Includes manufacturing solid waste. Non-manufacturing industrial
solid waste comes from demolition and supermarkets. For Fairfield
County manufacturing solid waste equals 48f million pounds per year,
demolition and supermarkets waste is 525 million pounds per year, and
the total manufacturing and non-manufacturing industrial solid waste
is 1,010 million pounds per year. Based on national averages,
approximately 55 percent of industrial solid wastes is disposed of in
industrial sites.
-50-
-------
TABLE 22
INDUSTRIAL WASTE FOR DISPOSAL IN CONNECTICUT
BY COUNTY FOR 1975
Total**
County
Fairfield
Hartford
Litchfield
Middlesex
New Haven
New London
To Hand
Wlndham
Manufacturing
Employment
112,830
169,092
17,353
16,820
125,524
39,431
7,205
14,150
Manufacturing
Solid Waste
(MPY)*
513
671
77
102
644
160
32
84
Total
Employment
280,378
442,267
47,445
50,746
335,454
98,504
27,841
30,634
Industrial
Solid Waste
(MPY)*
1,091
1,312
187
212
1,247
347
100
151
TOTAL
502,405
2,283
1,313,269
4,647
* Million Pounds Per Year
* Includes manufacturing solid waste. Non-manufacturing industrial
solid waste comes from demolition and supermarkets. For Fairfield
County manufacturing solid waste equals 485 million pounds per year,
demolition and supermarkets waste is 525 million pounds per year, and
the total manufacturing and non-manufacturing industrial solid waste
is 1,010 million pounds per year. Based on national averages,
approximately 55 percent of industrial solid wastes is disposed of in
industrial sites.
-51-
-------
SECTION IV
REFERENCES
1, United States Department of Commerce, Bureau of Census. City and County
Data Book, 1952
2. United States Department of Commerce, Bureau of Census. City and County
Data Book, 1962.
3. United States Department of Commerce, Bureau of Census. Census of
Population by State, 1960.
4. United States Department of Commerce, Bureau of Census. Census of
Business by State, 1963.
5. United States Department of Commerce, Bureau of Census. County Business
Patterns, 1964.
6. United States Department of Commerce, Bureau of Census. Statistical
Abstract of the United States, 1964.
7- United States Department of Commerce, Bureau of Census. Population
Estimates,
8. New York World Telegram and The Sun. World Almanac and Book of Facts,
1964.
9. National Planning Association Center for Economic Projections.
10. Connecticut Interregional Planning Program. The Socio - Economic Grgwth.
Model.
11. Voorhees, A. M. and Associates, Inc. A Model for Allocating Economic
Activities into Sub-Areas in a State. Prepared for the Connecticut
Interregional Planning Program, 1966.
12. Connecticut Interregional Planning Program. Study_Procedure Manual
III-A 1 to 4, July 1964.
13. Kurker, Charles, Connecticut State Health Department.
14. Connecticut State Department of Health. Weekly Health Bulletin,
March 1965.
-52-
-------
SECTION V
APPENDIX A
WESTERN UNION QUESTIONNAIRE FOR
DEPT. OF HEALTH, EDUCATION AND WELFARE
Nane .
Title
City
Good day, this is Western Union calling. We are conducting a survey for Combustion
Engineering, Inc. under contract for the United States Department of Health, Education
and Welfare. The K.E.W. contract number is P 06-66 163.
1. What method is now used for the disposal of your municipal refuse at the
present time? Check one:
A. Open dumping
B . Open burning
C. Sanitary land fill
D. Composting
E. Incineration
F. Feed garbage to hogs
G. Other (state)
2. If you dispose of the refuse by open dumping, open burning or sanitary land fill,
what is the hauling distance from the center of the city to the disposal site?
miles
3. How long will you be able to use the present site?
years
4. If you dispose of the refuse by either incineration or composting, what is the
total capacity of your facility on a 24 hour/day basis?
tons per 24 hour day
5. What percentage of your refuse do you incinerate or compost?
6. When was your incinerator or composting plant installed?
__ __ year
-53-
-------
Western Union Questionnaire Page 2
7. How many hours per week is each incinerator operated?
hours per week
8. How many incinerators or composting plants and of what size do you intend to
install in the next two years?
Size Tons per day
-54-
-------
industrial imrentom
(uolume ii)
-------
TECHNICAL - ECONOMIC STUDY OF SOLID WASTE
DISPOSAL NEEDS AND PRACTICES
VOLUME II - INDUSTRIAL INVENTORY
Conducted for the Public Health Service
under Contract #Ph 86-66-163
Prepared by
Dr. L. Koenig
Louis Koenig Research
San Antonio, Texas
Wens ley Barker, Jr.
Senior Product Analyst
Product Diversification Department
COMBUSTION ENGINEERING, INC.
WINDSOR, CONNECTICUT
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. INTRODUCTION 1
II. SUMMARY 2
III. CONCLUSIONS ........... 13
IV. RECOMMENDATIONS FOR FUTURE ACTIVITY . ..... 15
V. SURVEY METHOD AND PROCEDURE
A. SELECTION OF INDUSTRIES 16
B. SELECTION OF PLANTS ..... 16
C. DATA COLLECTION . 17
D. PROJECTIONS FOR TOTAL WASTE QUANTITIES ....... 18
E. PREFATORY NOTE ON STRUCTURE DEFECTS IN THIS REPORT ...... 19
VI. SURVEY RESULTS
A. SAW MILLS AND PLANING MILLS 21
B. SUPER MARKETS 34
C. COTTON GINNING 36
D. DEMOLITION ............... . 43
E. PAPER 48
F. FOODS 51
G. WOODEN CONTAINERS ........... ; ...... 53
H. WOOD FURNITURE AND FIXTURES . 57
I. AUTO AND AIRCRAFT MANUFACTURE ... ....... 59
J. MEAT PACKING 61
K. CHEMICALS ...... ..... 65
L. STOCKYARDS .......... 68
M. PAINTS _ _ 8Q
N. ELECTRICAL MACHINERY ...... Q,
ol
0. RUBBER 00
co
-1-
-------
TABLE OF CONTENTS. Cont.
P. GLASS 87
Q. ASPHALT ROOFING 90
R. MILL WORK 91
S. TANNING 93
T. PRINTING AND PUBLISHING 95
U. TEXTILES 98
V. APPAREL 100
W. FABRICATED METAL PRODUCTS AND MACHINERY EXCEPT ELECTRICAL . . 102
X. SPECIAL WASTE TYPES 104
VII. GENERAL DISPOSITION - DISPOSAL PATTERNS 108
VIII. NON-PROJECTED MANUFACTURING CODES 122
IX. WASTE FOR DISPOSAL BY STATE 129
X. WASTE FOR DISPOSAL BY COUNTY IN CONNECTICUT ..... 139
XI. REFERENCES 146
XII. APPENDICES
A. INDUSTRIAL CHECK LIST 148
B. MATHEMATICAL HANDLING OF WASTE QUANTITY DATA 152
C. LOG - NORMALITY OF THE MULTI-CODE SAMPLE 161
D. MATHEMATICAL HANDLING OF DISPOSITION AND DISPOSAL DATA ... 166
-ii-
-------
SECTION I
INTRODUCTION
The material presented in this report is part of a technical - economic study
of solid waste disposal needs and practices conducted under contract
Ph 86-66-163, with the Department of Health, Education and Welfare. The
tot.al study is reported in four volumes:
Volume I - Municipal Inventory
Volume II - Industrial Inventory
Volume III - Information System
Volume IV - Technical Over-View
This report presents the Industrial Inventory. It is based on interviews of
320 plants in twenty-four selected industries and presents an inventory of
the amount of waste for disposal generated by each of these industries, its
disposal, and an estimate of the quantity of such waste in 1975. Excluded
from this inventory by direction of the contracting agency were such sources
of waste as: agricultural waste, mining and primary metals manufacturing
wastes, and wastes from institutions.
This report was prepared by Dr. Louis Koenig, Louis Koenig Research,
San Antonio, Texas and Wensley Barker, Jr., Product Diversification Depart-
ment. Mr. Ralph J. Black was Project Director for the Public Health
Service; Mr. Elliot D. Ranard was Program Manager for Combustion Engineering, Inc,
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SECTION II
SUMMARY
A. METHOD
In twenty-four S.I.C. Codes, mostly manufacturing, there were conducted
169 plant interviews to determine waste production, disposition and dis-
posal. In addition, there were available the results of prior inter-
views, similarly directed, such that the total number of interviews
utilized in this study was 320. The locations of most of these inter-
views are spotted on the map, Figure 1.
In some codes, waste/product ratios were determined which, when multiplied
by the total 1965 production, projected the waste of each code subject
to ultimate disposal. For most codes, a waste/employee ratio in terms of
thousands of pounds a year per employee (Kpye) was obtained. The Kpye
values for any code showed a dispersion, but for practically all codes,
this dispersion was log-normal and by a mathematical manipulation, the
average Kpye for the population of establishments in the code could be
estimated.
The interviews also developed the fraction of total waste which was
utilized in some way, either given away-, sold or utilized as a by-product,
so that by subtraction the Kpye corresponding to the waste requiring
ultimate disposal could be obtained. In a few cases where the fraction
of the waste utilized was large, the Kpye's were adjusted to provide
Kpye's with respect to the waste requiring ultimate disposal.
The data for disposition were combined to show the frequency of disposition
agent, whether self, contract, or municipal pick-up; the ultimate
disposal type, whether open dump, dump and burn, sanitary land fill,
tepee burn or incineration; and the ownership of the ultimate disposal
facility, whether self, contractor owned, merchant or municipal.
By means of change ratios (the ratio of physical production estimated
for 1975 to physical production for 1965) there were predicted the 1975
wastes for ultimate disposal, adjusted where possible by recognizable
trends expected to be experienced in this decade.
WASTE QUANTITIES, PROJECTED CODES
The statistics, projections and predictions for the twenty-four codes
are shown in Table I. (Also in Table I are the "non-projected" codes
mentioned later in this summary.) The A mean Kpye signifies the average
Kpye, for the code, computed by the mathematical technique described.
The column headed "Waste Ratio Other Than A Mean" describes the waste/
product or other ratios used where Kpye was not used. The 68 percent
confidence interval represents, mostly for Kpye's, the range within which
there is a 68 percent probability that the true mean of the population lies
The estimated 1965 waste for disposal is shown in units of million pounds
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LOCATION OF INDUSTRIAL INTERVIEWS
NUMBERS, INDICATE TOTAL INTERVIEWS IN ONE
CITY OR ITS METROPOLITAN AREA
Figure 1
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TABLE I
SUMMARY OF WASTE RATIOS. PROJECTIONS AND PREDICTIONS
PROJECTED
S.I.C. Code Interviewed
MANUFACTURING
20
201
221, 2, 3, 5, 7, 9
231, 2, 3, 4
244
2421
2431
25, ex. 14, 15, Z2, 42, 91
26, ex. 2611
2732, 275, 276
281, 282, 2895
285
2952
301, 306
311
321, 322
3411
342, 3, 4, 351, 2, 3, 4, 6
361, 2, 3, 5, 6, 7, 9
371, 372
Total 20 Manufacturing
Total 19 Manufacturing
NON-MANUFACTURING
0712
1795
4731
5411
Industry
Food
Meats
Textile Mill Products
Apparel 6. Related Products
Wooden Containers
Saw Mills
Mill Work
Wooden Furniture
Paper
Printing & Publishing
Chemicals
Paints
Asphalt Roofing
Rubber
Tanning
Glass
Metal Cans
Fabricated Metal Products &
Machine Except Electrical
Electrical Machinery
Auto & Aircraft
Code Groups
Code Groups (Except Saw Mills)
Cotton Ginning
Demolition
Stockyards (incl. Auction)
Super Markets
Number of
Interviews
14
19
10
9
15
30
9
16
29
10
13
8
8
13
7
7
3'
18
20
9
267
237
13
16
11
13
X Mean
Kpye.
Proiected on
11.2
3.88
.792
125
16.3
14.6
19.4
51.4
281: .47
Other: 12.6
5.25
82.5
11.9
19.4
111
6.3
18.1
6
2.75
, 2.34
Other Waste
Ratios
Projected On
Ibs/head
Ibs/board feet
68%
Confidence
Level
6.7-20
1490-2400(4)
2.64-5.70
.554-1.13
91-172
11-23
8.1-26.2
15.5-24.4
29.4-90
.33-.61
7.6-21
3.6-7.7
51-133
6.7-21.3
9.0-42
72-150
3.1-9.3
16.6-19.7
4.58-7.86
2.18-3.46
1.4-4.0
Quantity, Waste For
Disposal,'Million/Lb/Yr.
Ibs/bale
Ibs/capita SMSA's
34 Ib/cattle equivalent 24-48
29-57
Total Non-Manufacturing
Total 24 Codes Manufacturing & Non-Manufacturing
Total 23 Codes Manufacturing & Non-Manufacturing
(Except Saw Mills)
1965 Est.
10,584
1,650
1,706
696
2,470
65,600
570
3,090
9,950
2,318
113
2,512
324
1,148
2,900
598
2,680
183
6,020
2,760
2,910
120,782
55,182
1,572(1)
38,100
779
20,310
60,761
181,543
115,943
1975 Red.
14,076
2,400
2,132
1,037
2,190
23,000(5)
890
5,170
14,700
3,222
4,900
390
1,538
3,900
670
3,936
258
8,758
4,968
3,660
101,795
78,795
1,665
44,300
779(7)
26,400
73,144
174,939
151,939
Projected On Codes
20, ex. 11, 13, 15, 43, 44, 51, 61, 95
2011, 2013
22, ex. 226, 8
23, ex. 235, 7
244, 42, 43, 45
242
2431
2511, 12, 19, 21, 253, 41, 99
26, ex. 2611
2732, 275, ex. <250 emp., 276
281, 282, 2895, 287
285
2952
30, ex. 307
311
321
322
3411
34, ex. 3411, ex. 345, 6, 7, 8, 9 & 35
36, ex. 364
371, 372
0712
1795
4731 S, Auction Yards
5411 (>19 emp.)
Total Employees
Proiected On
982,220
225,000(2)
677,600
1,238,354
29,737
236,910(2)
65,919
268,736
570,000
140,900
281: 240,500
Other: 199,400
62,000
14,300
247,000
30,800
23,000
95,000
53,745
20,056,286
1,327,581
1,361,144
10,146,132
9,909,222
>25, 000(2, 3)
8,449(2)
>3,000(2, 6)
568,000
10,750,581
10,513,671
Waste For
Disposal,
Kpye
10.8
7.3
2.52
.562
85
277
8.65
11.5
17.5
16.5
.47
12.6
5.3
80.5
11.9
19.4
93.21
5.28
3.40
2.93
2.08
2.14
11.9
5.56
<63
4510
<260
35.7
16.9
11.0
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TABLE I
NON-PROJECTED
S.IvC. Code Interviewed
19
2015
2043
2044
2051
2061
2095
21
226, 8
235, 7
241
2432
2433, 249
2514, 15, 22, 42, 91
2611
291, 2, 31, 4, 7, 8, 9, 275 (<250)
28, ex. 281, 2, 95, 5
307
31, ex. 311
32, ex. 321, 2, 3
323
33
345, 6, 7, 8, 9
364
37, ex 371, 2
38
39
Total Non-Projected
.Industry
Number of
Interviews
Ordinance & Accessories
Poultry
Cereal
Rice
Bakeries
Sugar
Coffee
Tobacco
Textile, Residual Codes
Apparel, Residual Codes
Logging
Veneer & Plywood
Pre-fab Homes & n.e.c. Wood
Metal Furniture
Pulp Mills
Printing Publishing Residual
Chemical Residual Ex. Paints
Plastic Products
Leather Ex. Tanning
Stone Clay Products
Glass Products
Primary Metals
Fabricated Metal, Residual Codes
Lighting & Wiring Devices
Transportation Equipment, Residual
Instruments & Related Products
Miscellaneous Manufacturing
5
2
10(8)
3
11(9)
3
JTE RATIOS, PROJECTIONS AND PREDICTIONS
X Mean Other Waste
Kpye, Ratios
Proiected on. Projected on
20% x Hulls
Quantity.
68% Disposal.
Confidence
Interval 1965 Est.
711
0
392
285
1,349
0
0
813
452
23
0
0
7,467
787
239
12,903
3,099
2,027
5,727
2,097
138
3,503
1,457
287
569
1,665
1,696
Waste For
_Mill/Lb/Yr
1975 Red.
876
0
514
373
1,767
0
0
967
565
34
0
0
9,767
1,314
348
17,870
5,795
3,359
6,523
3,028
199
4,442
2,054
517
717
2,734
2,474
Proiected On Codes
19
2015
2043
2044
2051
2061
2095
21
226, 8
235, 7
241
2432
2433, 249
2514, 15, 22, 42, 91
2611
271, 2, 31, 4, 7, 8, 9, 275 <250
283, 284, 289 x 2895 + 286
307
31, ex. 311
32, ex. 321, 2, 3
323
33
345, 6, 7, 8, 9
364
37, ex. 371, 2
38
39
Total Employees
Projected On
242,942
65,349
11,665
4,321
226,298
9,657
14,012
75,243
179,728
41,270
79,135
67,778
85,801
110,381
13,720
784,485
245,927
170,315
295,185
418,775
25,987
1,151,851
497,720
138,186
266,453
310,537
369,608
Waste For
Disposal
Kpye
2.93
0
33.6
66
5.96
0
0
10.8
2.52
.562
0
0
87.0
7.13
17.5
16.5
12.6
11.9
19.4
5.01
5.28
3.04
2.93
2.08
2.14
5.36
4.59
38
47,686 66,237
5,902,329
8.1
PROJECTED AND NON-PROJECTED
Total All Manufacturing Codes
Total All Manufacturing Codes Ex. Saw Mills
Total All Codes Manufacturing & Non-Manufacturing
Total All Codes Manufacturing Ex. Saw Mills
358
168,468
102,868
229,229
163,629
168,032
145,032
241,176
218,176
16,048,461
15,811,551
16,652,910
16,416,000
10.5
6.5
13.8
9.96
(1) 1962 to 1963 season.
(2) Employees associated with code. Projection not on employee basis.
(3) At greater than five employees per establishment.
(4) On 1965 estimate.
(5) Assuming all sawdust and shavings sold in 1975.
(6) At greater than two employees per auction yard.
(7) Inserted same as 1965 to achieve a total.
(8) Waste computed at 20 percent of the rice hulls.
(9) Kpye not obtained from these interviews, but from postcard survey of 37 establishments
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DISTRIBUTION OF WASTE FOR DISPOSAL AMONG 21 CODE GROUPS
Qi
<
UJ
>-
\
CO
O
O
Q.
9
Ct.
O
LU
<
90,000
80,000
70,000
60,000
50,000
40,000
30,000
20,000
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3.000
2,000
1,000
900
800
700
600
500
400
300
200
100
Stoc
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Paints Q
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Inorgani
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Uphai
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w
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Radio
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Meat
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Chem.
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4. r
10 15 20 30 40 50 60 70 80 85 90
PERCENTAGE OF CODES HAVING LESS THAN INDICATED QUANTITY
Figure Z
-7-
95
98
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DISTRIBUTION OF WASTE FOR DISPOSAL: EMPLOYEE RATIOS IN 21 CODE GROUPS
Stock YardsO
Wooden Containers
Cotton GinningQ
Glass
Tanning
Printing and Publishing
Other Chem.
Rubber
Wooden Furniture
Radio and TV
Auto and Aircraft
"Average KPYC for
Community Waste
Inorganic Chemical
0.2
0.1
PERCENTAGE OF CODES HAVING
LESS THAN INDICATED RATIO
Figure 3
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The average Kpye's for various code groupings are also instructive. For
the nineteen manufacturing codes (ex. saw mills), the average Kpye is
5.56. Some of the codes which have individual Kpye's below this
average happen to have large numbers of employees. With saw mills
included, the twenty manufacturing codes have an average Kpye of 11.0.
This arises from the fact that the Kpye for saw mills is exceptionally
high, in fact, almost fifty times as high as the average of the rest.
When the four non-manufacturing codes are added, the average Kpye becomes
16.9. This occurs because two of the added non-manufacturing codes
have high Kpye's and also high mpy's. When saw mills is withdrawn
from the twenty-four code group, the Kpye for the remainder falls to
11.0, again reflecting the high mpy and high Kpye of saw mills.
C. DISPOSITION-DISPOSAL QUANTITIES, PROJECTED CODES
The general level of accuracy of the waste for disposal quantities is
indicated by the confidence intervals shown in Table I. The accuracy, for
disposition-disposal patterns and for utilization achieved, is of a
considerably lower order primarily because the disposition sample is
not nearly large enough to cover the known degree of geographical,
political and economic dispersity in the population which has a direct
bearing on disposition-disposal patterns. The quantities of scrap and
waste, defined as all solid material generated not appearing in the
primary product, and thus the utilization achieved of this scrap and
waste also has the deficiency that the project was not primarily directed
at this objective and it is likely that substantial scrap and waste
quantities have missed. Nevertheless, pending a more thorough investi-
gation, the results are presented for their value.
The total scrap and waste generated in the twenty-four code groups is
350,500 million pounds per year, of which the major portion is from
saw mills. The total for the twenty-three code groups excluding saw-
mills is 157,900. The degree of utilization achieved, measured by the
fraction of the scrap and waste which finds utilization is 48% for the
twenty-four code groups, and 27% for the twenty-three code groups.
This reflects not only the high contribution of saw mill, the total
scrap and waste, but also the high utilization achieved in the saw mill
industry, 66%. Other high achievements are cotton ginning, 59%; wooden
containers, 50%; mill work, 47%; auto and aircraft, 50%; stockyards,
60%; and printing and publishing, 68%. Utilizations of over 50% are
also achieved by fabricated metal products and machinery (except electrical)
The remainder of this section concerns the waste for disposal, namely
the 181,500 million pounds per year for the twenty-four code group or
the 115,900 for the twenty-three code group. By disposition agent,
about half of this is handled at the establishment site by the generator
and an additional one-quarter is handled by the generator by hauling
off the plant site. Contract disposition accounts for 21% and municipal
pick-up for 3%. When saw mills are excluded, about one-fifth is handled
at the site, two-fifths by the generator by hauling off the plant
site, and one-third by contract.
-9-
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As to type of ultimate disposal facility, incinerators and burners are
about equal with dumps, each around 40%, other modes being of small
importance. With saw mills excluded, dump is the major mode with 57%,
incinerator or burner and sanitary land fill having considerably
smaller percentages. This again indicates the importance of burning
as a disposal method for saw mills.
As to ownership of the ultimate disposal or reduction facilities, private
ownership is predominant with 50% followed by municipal with about 36%.
With saw mills excluded, the private ownership falls to 22% and municipal
becomes the major mode with 56%.
The portions of the total industrial waste for disposal, which are not
included in the quantity of solid waste developed by the municipal
portions of this project, are those that find disposition in self
owned ultimate disposal facilities. For the 24 codes this quantity is
about 91,200 million pounds and for the twenty-three codes, 25,700.
The major ultimate disposal type, among self owned facilities, is inciner-
ator or burner handling 76% of the waste for disposal in self owned
facilities, followed by dump 18%, with other modes of very minor impor-
tance. Excluding saw mills, the incinerator or burner still maintains
predominance with 62% and dumps become 25%, open burning gaining some
in relative importance.
D. WASTE QUANTITIES AND DISPOSITION-DISPOSAL PATTERN, NON-PROJECTED CODES
The number of manufacturing employees, on which the projections previously
summarized are based, is 10,146,000. There remain about 5,900,000
employees who are contributing to manufacturing waste for disposal, but
which are not covered in the wastes summarized in the projected codes.
An attempt was made to estimate the quantities of wastes generated by
these 5.9 million employees, based in part on prior non-project knowledge
of the Kpye's for certain codes, and in part by assignments of Kpye's
to non-projected codes according to similarities between non-projected
codes and the already studied projected codes. The results of this work
are contained on Page 2 of Table I showing a total of 47,686 million
pounds per year estimated for 1965 and 66,237 estimated for 1975 from
these non-projected codes. The accuracy of this figure, of course, is
of a lower order than that for the projected codes, and for that reason
it is presented separately so that the reader may make his own judgment.
The last four rows in Table I present the data for the projected and
non-projected codes combined; that is, for all manufacturing codes plus
the four non-manufacturing codes covered.
The total 1965 waste for disposal is 229,229 million pounds per year,
or except saw mills, 163,629. Waste from manufacturing codes makes up
168,468 million pounds per year of the former and 120,868 million
pounds per year of the latter. For all manufacturing codes, the average
Kpye is 10.5, or except saw mills, 6.5.
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The disposition disposal pattern and distribution, when non-projected
codes are included, is practically the same as that for the projected
codes only, discussed in the previous section. For example, about
two-thirds of industrial waste collected by contractors is taken to
municipal owned ultimate disposal or reduction facilities and about
one-third is handled in contract owned or merchant facilities.
SPECIAL WASTE TYPES
A study was made of certain special waste types from the interview data.
General plant trash averages about 1.3 Kpye. Codes 34, 35 and 36 are
prominent generators of metal wastes, most of which does not find its
way into the waste for disposal stream. In these codes, the metal
waste is of the order of 60% of the total scrap and waste.
F. WASTE FOR DISPOSAL. BY STATE
The same general method, used to project waste for disposal for the
United States3 was used, with some modifications, to project waste for
disposal for each of the fifty states and the District of Columbia.
For all codes covered, the top states are New York with 22,580 million
pounds per year (in 1965) followed by California, Pennsylvania,
Illinois and Ohio, in that order, Ohio having 11,470 million pounds
per year. With saw mills excludeds the same five states are in the top
five, but California falls somewhat in rank.
The ranking is different when measured in terms of waste generation
intensity per capita, the Kpyc ratio (thousand pounds of waste for
disposal per year per capita of total resident population, 1965). The
highest states are, in general, the lumbering states which do not have
much manufacturing (i.e. much population). Oregon leads with a Kpyc of
5.39, compared to the U. S. average of 1.18. The Great Basin states,
having little lumbering and little manufacturing, are the lowest, Nevada
with .38, Utah with .47. The industrialized states of the Northeast
are close to the national average, New York for example, having 1,25
and Pennsylvania having 1.26, The national average figure of 1.18
corresponds to 3.2 pounds per capita per calendar day.
Corresponding to the national average for projected plus non-projected
codes of 6.50 for the Kpye for manufacturing (ex. saw mills), the
comparable state Kpye's range from 4.6 to 15.4 with a median of 7.4.
The study was undertaken to determine whether the variations in S.I.C.
Code profiles among the states might be small enough to allow the use of
a single Kpye figure applied against all employees in manufacturing,
except saw mills, short cutting the code by code method. The results
showed that the S.I.C. Code profiles do vary appreciably and the code
by code method must be used for projection.
G. WASTE QUANTITIES IN CONNECTICUT COUNTIES
The same approach further modified, and further generalized to include
projected and unprotected codes in a single Kpye was applied to project
the waste for disposal for the individual counties for Connecticut for
1965 and to predict these for 1975.
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In 1965, Hartford County makes the largest contribution with 1,047
million pounds per year (manufacturing and non-manufacturing) followed
closely by New Haven and Fairfield. This ranking is maintained in 1975,
The highest percentage growth in the period is for Tolland with 44%
and Middlesex with 40%. The Kpye's in individual counties, manu-
facturing codes only, range from 3.87 to 6.76, the eight county
Connecticut average being 4.65.
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SECTION III
CONCLUSIONS
A. It has been found that the dispersions of waste quantity per employee
for nearly all of the industries studied were log-normally distributed.
This being so, it was possible to calculate from a small number of
samples the mean waste quantity/employee for the industry as a whole and
therefore, to predict with satisfactory accuracy the total waste pro-
duction of the industry.
B. The waste for disposal generated by the industries in the twenty-four
projected codes was calculated to be 181,500 million pounds per year in
1965. This is based upon an employee population of 10,146,000. The
non-projected codes within those industries represent an employee
population of 5,900,000 and the waste generated by this segment of the
industrial population was estimated and added to the previous figure
giving a total industrial waste figure for the twenty-four codes of
229,229 million pounds per year.
C. The dispersion - disposal results are known with somewhat less accuracy
than the waste quantity figures, but it is significant that within the
twenty-four codes studied, 48 percent of the waste is utilized in some
manner. If saw mills, which have a high waste utilization factor are
excluded, only 27 percent of the waste is utilized in the remaining
industries.
D. Fifty percent of the industrial waste surveyed was disposed in private
facilities with 36 percent going to municipal facilities. If saw mills,
which are a large generator of waste are excluded, 22 percent of the
industrial waste goes to private facilities and 56 percent to municipal
faciliites. Forty percent of this waste is burned in either incinerators
or by open burning. Forty percent is disposed of in dumps. Again excluding
saw mills, 57 percent of this industrial waste goes to dumps. These
figures indicate that the same pressures of decreasing land availability
and air pollution regulations which have been noted in the municipal
section of this report will be felt by disposers of industrial waste
and the problem will become more acute with time.
E. This industrial inventory has shown that a large percentage of industrial
waste is of a uniform character and is independent of the industry
involved. This waste consists of shipping waste, plant trash, and office
waste.
F. Two industries, food and chemicals, are characterized by process wastes
which are peculiar to the process involved. Determination of the
character and quantities of this waste would require further detailed
study.
G. It will be noted that the largest producers of waste are those industries
in the wood and wood products categories, S.I.C. Code 24. While a great
-13-
-------
deal of utilization of these wastes exists in these industries, it is
apparent that the problem of disposal of this tremendous quantity of
sawdust, shavings, etc. without resulting air pollution is increasing.
H. Many industries such as paper mills are presently disposing of large
quantities of waste in a liquid form to streams and sewers. The
pressures of stream anti-pollution regulations will require in the future
that this waste be captured and disposed of by other means such as
land fill, incineration, etc.
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SECTION IV
RECOMMENDATIONS FOR FUTURE ACTIVITY
A. It is recommended that industries such as foods and chemicals, which
have process wastes which are peculiar to the process involved, be
studied in detail to define further the waste disposal problems and
practices in these industries.
B. It is recommended that consideration be given to the development of an
incinerator suitable for burning sawdust and wood wastes in an air
suspension and with suitable air cleaning devices to prevent air
pollution.
C. It is recommended that an incinerator be developed which would be
suitable for burning the semi-liquid wastes in sludge form which are now
being disposed of in streams.
D. Many industries have process waste which has a high Btu content and
represents a disposal problem. It is recommended that preparation and
blending systems be developed to take wastes such as asphalt, rubber,
plastic and so forth and prepare them for blending with municipal waste
in municipal facilities. A cooperative arrangement between municipal
waste disposal facilities and small local industries, which generate
this type of waste, appears to be the most efficient way to dispose of
these materials.
E. It is recommended that the development of a system for separation and
preparation of combustible demolition wastes be encouraged to permit
incineration of these wastes.
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SECTION V
SURVEY METHOD AND PROCEDURE
A. SELECTION OF INDUSTRIES
Prior to the present contract, Combustion Engineering and Louis Koenig
Research conducted investigations of industry waste generation of a
large number of industries. This previous data was used to select
the industries which are the largest generators of solid waste.
Specifically excluded were mining wastes, petroleum industry wastes
and junked automobiles which are under the cognizance of the Department
of the Interior. Also excluded were agricultural wastes and institutional
wastes.
As a first approximation, industries so selected were chosen to
represent potential disposal problems. This previous data was used
only for this selection of industries. The data generated during the
interviews conducted under the H.E.W. program was used to estimate total
waste production of the industries selected. The industries listed
below were approved by the Department of Health, Education and Welfare for
evaluation.
Saw Mills
Super Markets
Cotton Ginning
Demolition
Paper
Foods
Wooden Containers
Wood Furniture & Fixtures
Auto & Aircraft Manufacture
Meat Packing
Chemicals
Stock Yards
Paints
Electrical Machinery
Rubber
Glass
Asphalt Roofing
Mill Work
Tanning
Printing & Publishing
Textiles
Apparel
Fabricated Metal Products
Machinery (except electrical)
B. SELECTION OF PLANTS
Within each of the twenty-four selected industries an analysis of the number
of establishments versus the number of employees per establishment was
made using census data, to determine the plant size pattern of the
industry. Selections of plant sizes to represent small, medium and large
establishments in this industry were made and six specific plants, to
be interviewed in each of the twenty industries, were chosen. These
selections, made to present a cross-section of size and geographic
location within the industry, were chosen from the plant and product
directory published by "Fortune" in 1966 and the state directories of
manufacturing establishments.
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C. DATA COLLECTION
Personal interviews were made in each of the 169 plants selected. An
interview check list previously approved by the Department of Health,
Education and Welfare, a sample of which is contained in Appendix A,
was used by the interviewer to insure the uniformity of information
obtained. Most of the information required was readily obtained.
It was found that, in general, it was preferable for the interviewer to
contact the plant manager or plant engineer to obtain the information
desired. In most of the large plants, information as to the character
of waste, quantities produced and disposal problems was readily
available. In the smaller plants, the stated quantities usually
represent on-the-spot estimates by the plant personnel responsible.
During interviews of some of the industries, it was not too difficult
to obtain information on solid waste generation and disposal once the
interviewer established that this was his principal interest; however,
extreme reluctance to discuss liquid waste was noted. This is obviously
indicative of problems in this area and fear of regulation in advance
of acceptable disposal methods.
Computations on waste quantities were made subsequently using the inter-
view data supplemented by additional information and estimates as to
bulk densities, units of measurement, etc. In some cases, new data
were generated on the spot. Measurements, for example of truck body
sizes, container sizes, etc. were made when the interviewee could not
state them of his own knowledge. In other cases, interviewees were
asked if they would make special measurements subsequent to the inter-
view. For example, several interviewees conducted experiments on bulk
densities of their wastes and forwarded the information later.
Where necessary, interviews were followed up by phone calls in order to
clarify questionable points or obtain information later found to be
needed.
All of the codes covered in this study had previously been studied in
a somewhat similar manner under various proprietary research projects
of Combustion Engineering. Indeed, as previously noted, the selection
of these codes had been based on the information thus developed. From
these prior studies there were available additional interviews in most
of the codes studied, and it was possible for the most part to incor-
porate these interviews in the basic data of the present study. The
prior interviews had been conducted for somewhat different purposes and
did not conform in all of their information to that in the present
interviews.
In addition, some of the prior projects had conducted postcard surveys
to determine disposition patterns in certain codes. The results of these
postcard disposition surveys were incorporated in the present study where
applicable. The postcard information comprised only the mode of
disposition and ultimate disposal of the waste and gave percentages of
the total waste, unspecified as to type, which was handled by the various
disposition and disposal modes.
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A word about the units used, in the computations* is in order. For waste
quantities the unit used herein is thousand pounds per year of waste
(Kpy). This quantity says nothing about the number of pounds per month,
per week, per day, or per hour, but simply totals for whatever number
of hours, days, weeks or months per year that the waste is produced.
For the waste/employee ratio, there is used thousands of pounds per year
per employee (Kpye). The Kpye is the number which when multiplied by
the total number of employees in the establishment will produce the total
amount of waste produced annually. This Kpye says nothing about the
number of hours which each employee must put in producing that quantity
of waste. In some establishments he may put in 261 days per year, in
others 312, etc. Presumably, if it be assumed that the waste production
per employee hour is constant then the dispersion in employee hours per
year is responsible for some of the dispersion in the Kpye's.
To determine whether there was a trend in waste/employee ratio or waste/
product ratios with establishment size, the ratios were plotted on
log-log paper against the number of employees. In most cases, it was
obvious that there was no trend with size. In those cases, which were
not obvious5 a regression line was computed and the significance of the
difference between the slope of the line and a slope of zero was determined
by standard statistical techniques.
D. PROJECTIONS FOR TOTAL QUANTITIES AND PATTERNS
The total quantity of waste generated in a code was obtained by multiplying
the average Kpye by the number of employees in that code, or group of
sub-codes. The number of employees in each S.I.C. Code was taken from
Reference 2 which gives employment in March 1964. The employment data
were for 1964 and the interview data generating waste quantities, Kpy,
were obtained during 1966. It would not have been feasible,
with the interviewing methods used, to develop the quantities of wastes
for 1965 or 1964 since it was difficult enough as it was to generate
quantity figures arising out of the recent past at the time of the
interview. If S.I.C. Codes are in general expanding, this means that the
number of employees is increasing each year and also the amount of waste
generated is increasing. If that be the case, then the 1966 waste used
in the computations would be too high for 1965 conditions and the 1964
employees used in the computations would be too low. Overall, the
waste/employee ratio would be too high compared to the true 1965 ratio.
However, with dispersion such as found in the basic data it is highly
unlikely that any significant differences in the projections would have
been found if both the waste generated and the number of employees had
been for the 1965 period.
In certain codes, for special reasons, pertaining thereto, the waste/
employee method was not used, but the waste/product ratio or other waste
ratio was used as being superior.
From the total quantity thus projected, there was subtracted the waste
and by-product not entering the waste stream of interest, namely that
sold, given away, or utilized for fuel or otherwise.
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While the waste/employee ratio was preferable, as described for projecting
the current waste, the future trend of the waste/employee ratio is not
predictable and therefore, it becomes an insecure basis for projecting
the 1975 waste. For the purpose, it was assumed rather that the waste/
product ratio would reamin about the same during the next ten years,
except in special codes where the trends were contradictory to this.
There was available a set of change ratios, being the ratio of the
1975 estimated physical production to the 1965 physical production, in
each code.
The change ratios for physical production were used to adjust the current
total waste to the estimated 1975 waste. For meat packing and stock-
yards, the trends indicated that the waste/product ratio might change
greatly in the next ten years and projections by the change ratio method
are insecure. Special projections, not using the change ratios, were
also applied for cotton ginning and for demolition.
Under the disposition and disposal section of each code chapter there
are given the tallies which describe the disposition agent, the ultimate
disposal facility ownership and the ultimate disposal type. While the
information is given for each code, there is, in general, no reason why the
code should control the disposition and disposal pattern in those
aspects. If it is found that in six out of eight interviews the waste
goes to a city sanitary land fill, this very likely means that in six
out of eight interviews the establishments were located in cities that
had sanitary land fills. If they had been located in cities having
incinerators5 six out of the eight might have gone to an incinerator.
Likewise, whether the waste is self hauled, contractor hauled or enjoys
city pick-up is certainly no characteristic of code, but merely reflects
the economics of a particular situation in which the interviewed
establishments found themselves. Accordingly, unless there is some
overwhelming trend for which a physical reason can be assigned, these
disposition and disposal patterns by code have little significance.
However> taken all together, they do represent frequencies for disposition
and disposal patterns and the general tally reported was undertaken with
this purpose.
E. PREFATORY NOTE ON STRUCTURE DEFECTS IN THIS REPORT
This report contains some defects in structure which are residual from
the prescribed method of conducting the project. It may benefit the
reader to have the project sequence in mind if he should notice these
defects. Stage one of the project comprised the survey of twenty codes
and the preparation of a report thereon. The original objective was to
be concerned only with waste for disposal and the report touched upon
other portions of scrap and waste only insofar as was necessary to
statistically manipulate the data. When this report was in the final
stages, it was requested to incorporate therein the scrap and waste and
the fraction utilized. The main body of this subsidiary work is contained
in "General Disposition Disposal Patterns", Section VII, but this also
required some modifications in the individual code chapters. There are
some defects residual in this supplementation.
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The second stage of the project was originally designed to make a
deeper study of some of the original twenty codes. Instead, the second
stage was recast to cover the extension to five additional codes, and a
projection of waste totals for "non-projected" codes. This contradiction,
of projecting non-projected codes, comes about because the basic data
obtained for certain 4-digit codes were projected to total waste
quantities by using the employees in these interviewed codes and those
in certain closely related codes whose waste/employee ratios could
confidently be expected to equal' those for the interviewed codes. There
remained a number of 4-digit codes, and the employees in them, for which
the waste was not projected. These constituted the non-projected codes.
It was then decided to attempt to project the total waste production
for the nation and also for the fifty states individually. This required
that waste production be projected for the codes previously not pro-
jected. This is the substance of "projections of non-projected codes".
The work on the non-projected codes is reported in a separate chapter
and the data thereon are presented separately in the summary in order
that the reader may distinguish between relatively secure projections
and those which are based on less secure assumptions concerning waste/
employee ratios.
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SECTION VI
SURVEY RESULTS
A. SAW MILLS AND PLANING MILLS
1. THE INDUSTRY
S.I.C. Code 242, saw mills and planing mills, includes general saw
mills and planing mills 2421, hardwood dimension and flooring mills
2426, and special products saw mills not elsewhere classified 2429.
It specifically does not include logging except where the logging
is conducted in direct combination with the saw mill and reported as
such. The waste figures to be used and generated exclude the logging
waste and cover only the waste generated between the delivery of the
log to the mill and the shipping of the dressed finished lumber.
Saw mills are also operated in connection with wooden container
manufacture and certain other industries in the lumber and wood
products code, but these are not covered in Code 242. Hardwood
dimension is hardwood cut to prespecified dimensions for "remanufacture"
into other wood products. Hardwood flooring mills are saw mills which
proceed a little further into "remanufacturing" in milling the
typical flooring board shape from the rough dried lumber blanks rather
than putting the rough lumber through the planing mill to produce
lumber.
The overall operations, with respect to waste production of most saw
mills can be represented by some path on the flow sheet, Figure 4.
Some saw mills may start with the cants, but the typical saw mill
starts with the log. This may be debarked, producing the bark waste
and yielding a debarked log. The debarked log is usually made into
a cant; that is, a squared-up log, by sawing the rounded slabs off
the four sides. The waste from this operation is the slabs and edges.
As will be described, there is a market for wood chips in the pulp
industry and, therefore, it is common to chip up the slabs to produce
these saleable chips. Because of this outlet, another route may be
followed in which the debarked logs are squared-up directly by chipping
rather than going through the slabbing operation. When a debarker
is not used, the slabs and edges contain the bark. Sawing the slabs
and also sawing the cants themselves produces green sawdust and yields
rough green lumber. At this point, the lumber leaves the saw mill
proper.
Typically, the rough lumber is dried either in a heated kiln or in
the air to produce dried rough lumber. This dried rough lumber is the
feed to the planing mill, although in some instances, green rough
lumber may be sent through the planing mill without drying. The
rough lumber is put through the planing mill, producing dry shavings
and yielding finished lumber. Saws in the planing mill trim the
finished lumber to length and also there may occasionally be some
resawing; that is, making thinner or narrower wood out of the original
rough lumber. This operation produces dry sawdust, dry shavings, and
mill trim and ends.
-21-
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FLOW SHEET FOR SAW MILLS
BARK
SLABS -<-
I
CHIPPER
CHIPS
GREEN SAWDUST
I
DEBARKER
\
DEBARKED LOGS
SLABBING OR CHIPPING
CANTS
SAWS
SHAVINGS -<-
DRY SAWDUST-^-
ROUGH LUMBER
AIR DRY OR KILN
DRIED ROUGH LUMBER
- PLANER -*-
I
SAWS-
FINISHED LUMBER
CHIPS
SAW MILL
PLANING MILL '
-RESAW 5 DRY SAWDUST
TRIM AND ENDS
Figure 4
-22-
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An important distinction is to be made between green waste and dry
waste since green waste is potentially utilizable for pulp. However,
dry waste is not generally acceptable by the pulp mills.
While veneer and plywood plants were not specifically studied,
their operations do bear upon some of the statistics to be presented.
A plywood plant starts with logs which may be debarked, but which
more typically are not. The log, usually eight feet longs is placed
in a lathe and turned down to become cylindrical. The wood and bark
removed in this operation is called "round up". It corresponds to
the bark and slabs produced in saw mills. The log is then peeled
down in the lathe, producing veneer, which corresponds to the rough
lumber of the saw mill. In this operation there is no sawdust, but
there is a residue comprising "a core" four to eight inches in
diameter, too small to peel further on the lathe. Some plywood mills
make eight foot studs from these cores by a sawing operation. Others
chip them for saleable chips.
The wet veneer is then dried, laminated into plywood by gluing and
the plywood sheets squared-up by sawing. This corresponds to the
planing mill operation and produces dry sawdust and trim but no
shavings.
The industry is sectionalized with production as shown in Table II
taken from Reference 4.
The first column, roundwood products total, refers to the quantity of
logs taken from the forest and delivered to the manufacturing plants.
There is also a wood quantity representing logging residues and the
total of these two is the saw timber harvested. In addition to
sawlogs, roundwood is also used for veneer -, for pulpwood, for fuel
wood and for miscellaneous industrial wood products. The last two
are very small in the total. Pulpwood amounts to 16% of the total
and the wastes from pulpwood have been accounted for in this study
in the paper industry. However, some of the general statistics to
be used include the wastes from pulpwood, as do they also for veneer
manufacture. Veneer manufacture probably has waste/product ratio
not much different from that for saw mills, so the use of waste/product
ratios for total roundwood products as a substitute for waste/product
ratios for sawlogs alone is admissible if the allowable error is of
the order of 10% (pulpwood does have bark waste which in sawmills
amounts to something of the order of one-third and one-fourch the total
waste).
The waste/product ratios for roundwood products total can be expected
to be something of the order of 12% lower than for saw mills alone
because of this inclusion. However, as will be seen, a 12% error
is allowable considering the accuracy of the other information.
2. INTERVIEWS
The saw mill code had been studied in prior Combustion Engineering
products and yielded 21 interviews in the South and in Oregon and
Washington. The interviews for the present project, therefore we
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TABLE II
1962 Billion BF International 1/4 Inch Board Rule
Roundwood
Products
Misc. Fuel
Total Sawlogs Veneer Pulpwood Ind. Wood
North
5.732
3.393
.240
1.335
.423 .341
South
41.608
9.396
.751
3.244
.835 .328
Rocky Mt.
3.714
3.438
.131
.096
.048 .001
Pacific Coast 21.521
14.790 3.898
2.491
.257 .084
Total
72.575
31.017 5.020
7.166 1.563 .754
-24-
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concentrated in California in order to cover the remainder of the
West. As the interviews progressed, it was found that contrary
to the situation in the South where quantities were fairly well
available, the disposition in California was such that little
record was kept of waste quantities. In an effort to overcome this
deficiency of quantitative data, nine interviews were conducted
rather than six. The total number of interviews from which the con-
clusions in the present study are drawn then are thirty plus two
literature references on overall waste quantities for the West and
one literature reference comprising a detailed waste study for
twenty-nine Douglas fir mills and one ponderosa pine mill in the
West.5
3. UNITS OF MEASUREMENT
The uses to which lumber is put make of prime importance the linear
dimensions of the piece. For this reason, the units of measurement
used in the saw mill industry are associated with linear dimensions,
and tend to neglect product and raw material weights. This is
extremely harassing for a study of waste generation and the conclusions
of this study must suffer from that.
The unit of measurement for lumber is the board foot, defined as
the equivalent of a board 12 inches wide, 1 inch thick and 1 foot
long. A 1 x 8 board, 18 feet long by this definition contains 12
board feet, which is the equivalent in volume of 1 cubic foot.
However, such a board 1 x 8 x 18 at no time in the whole history of
its manufacture is associated with or finds itself having the dimensions
of a piece of wood containing a volume of 1 cubic foot. As finished
dressed lumber, this piece would contain only 0.875 cubic feet. As
rough lumber, it would contain something of the order of 1.2 cubic
feet, and in the original Douglas fir log from which it might have
come, it would have been associated with about 2.2 cubic feet of log.
Indeed, on first approaching the saw mill industry, one welcomes the
conclusion that the industry has no waste since from a thousand board
feet of log it produces a thousand board feet of rough lumber, and
this in turn yields a thousand board feet of dressed lumber. The
reason for this is that the "log scales" used to measure the quantity
in a log is intended to measure the amount of lumber that can be
produced from the log under conventional mill practices. Such
measurement conventions result in the startling performance that the
yield from raw material can be greater than 100%. What this means
is that measured by the log scale the log is claimed to contain say
1,000 board feet, but by careful planning and saw mill operation the
operator may be able to produce 1,150 board feet out of it. His
yield therefore is 115%.
There are at least a half dozen log scales, in which the ratio between
cubic feet in the log and board foot measure varies, and of course
this relation varies with the diameter of the log within each scale.
In addition to these difficulties, the weights of a given volume
of log vary with the type of wood (having different densities,
-25-
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measured as grams of oven dry wood per cc of green wood volume),
and with the moisture content (measured as grams of water per gram
of oven dry wood). Means are provided (Reference 6) whereby the
weight of round timbers in Ibs./cf can be determined if one knows
the species, the diameter and the thickness of the sap wood.
In addition to the difficulties arising from units of measurement
of the lumber and the log itself, there are further difficulties
introduced by subsidiary units of measurement used for some of the
waste products. The cord, for example, used to measure the quantity
of pulp wood has with the introduction of chips for pulp been
translated to measure quantities of chips. In this use the cord
has several values. Another unit of measurement is called simply
the "unit". At least half a dozen different values for the "unit"
were revealed during the course of the interviews.
A development which has gained momentum in the South holds out some
hope that eventually quantity data in the saw mill industry may
come in a form more useful to waste and utilization studies such as
this one.
In the South it is well advanced to sell chips to paper mills. The
paper mill purchases the chips by weight (and moisture content) and
both producer and purchaser must then pay attention to the weight,
rather than the board feet of the chips, This leads to a higher
frequency of recording the quantity data on chip production, and
also to a greater accuracy in the measurement of it (when once one
has determined the units of the "unit"). When slabs and edgings
instead of being sold as chips were simply burned for fuel or burned
as a waste there was no record kept of the quantity. With the
imminence of utilizing other saw mill waste products for industrial
purposes, and therefore their entrance as articles of commerce, the
tendency to take and record weights is increasing. Indeed, some mills
actually now purchase logs by weight. This is referred to as the
"weight scale" in distinction to the "log scale". Such establishments
are able to provide information on the pounds/nominal board foot for
the log, the bark, the chips, the rough lumber, the shavings and the
finished lumber. Since the national statistical figures are in terms
of nominal board feet of production which is approximately equal to
the nominal board feet in the log, such a pbf (pounds/board foot)
measure becomes directly useful in waste studies. Unfortunately, some
of the interviews and all of the studies reported in the literature to
which reference was made provide data only in terms of the volume
per cent of the log going into the various waste streams. Thus, a
conversion is necessary in order to use both types of information.
4. WASTE QUANTITIES
The waste data for the mills in the three Pacific Coast states come
from eight individual interviews, two sets of literature data on
overall averages, and the detailed Voorhees study (Reference 5) on
twenty-nine Douglas fir mills and eleven ponderosa pine mills. Some
of these data sources provided information on combinations of the
basic streams, for example, on bark and sawdust together. The dry
-26-
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sawdust is very small in quantity compared to green sawdust, so
sawdust figures usually encompass both and are approximately the
quantity of green sawdust. In such cases, the bark and sawdust
where combined, were separated in the proportions found from the
average of other data sources where they had been separated.
In order to make the two sets of data, volume basis and weight basis,
comparable it was easier with the information at hand to convert the
pbf figures to volume per cent figures rather than the reverse. To
do this required a knowledge of the pounds of log per nominal board
foot. The Voorhees studies gave the nbf/cf (nominal board feet per
cubic foot) in the log as 5.45 for Douglas fir and 5.75 for ponderosa
pine. From Reference 6, log densities were computed for both woods
based on proportions, thought to be reasonable, of 50% sap wood in
Douglas fir and 36% sap wood in ponderosa pine. From the nbf/cf
it was then possible to compute Ibs./nbf in the log (pounds/nominal
board foot). These averaged 8.1 Ibs./nbf, range +10%. This figure
was used to compute volume per cent from pbf (pounds/board foot)
figures for the green waste streams. The values obtained for shavings
and for mill trim and planer ends were adjusted to represent dry
weights rather than wet weights by multiplying the pbf on the green
basis by 35/45 which is approximately the pcf (pounds per cubic
foot) of dry wood and the pcf of green wood.
When the interview average was compared with the Douglas fir and
ponderosa pine averages, it was found that the volume per cent figures
for bark, sawdust and for shavings were in close correspondence.
However, for chips the interview average was 25.2 volume per cent
while the corresponding figure, for slabs and edgings, for the mills
averaged 11.3% with an additional 4.7% for mill trim and planer
ends not identified as such in the interviews. This discrepancy
remains unexplained in the data, but it was handled as follows. The
sum of the identified waste streams averaged 50.7% and the mill
trim and planer ends averaged over the three sets was 3.1%. The
difference between the 50.7 and the sum of the averages for mill
trim and planer ends, shavings, sawdust and bark was 16.2% and this
was taken as the chosen figure for slabs and edgings or chips.
No literature reports or prior detailed studies were available for
the Southern saw mill industry, and accordingly the results are
based only on the eight interviews supplying quantitative data,
mostly in the pbf form. Where the data were in the volume per cent
form, the conversion was based on the 41 pcf for dry wood and 57 pcf
for green wood characteristic of long leaf yellow pine.
The results of the above described series of computations are shown
in Table III.The Pacific Coast data was taken as applying to both
Pacific Coast and Rocky Mountain regions here called Western. The
Southern data was considered as applying to both Southern and Northern
regions here called Eastern.
There was some discrepancy in the data regarding the pbf for the
original log in the Southern region. When the average pounds per
nominal board foot figures for each waste stream including that for
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TABLE III
Bark
Sawdust
Slabs or Chips
Shavings
Mill Trim
Total Waste
Original Log
Nominal Board Foot/Cubic Foot
in Log
Pound/Cubic Foot of Log
Nominal Board Foot/Cubic Foot
in Finished Lumber
Bark & Sawdust
(Volume) %
Shavings/Sawdus t
(Volume) %
Slabs or Chips
Sawdust (Volume) %
WASTE/PRODUCT
WESTERN AND
AND
OTHER
RATIOS
EASTERN SAW MILLS
Volume %
East
20
18
20
8
66
100
c Foot
.0
.0
.0
.5
0
.5
.0
West
12.2
13.0
16.2
6.2
3.1
50.7
100.0
Pound/Board Foot
East West
2.40 0.99
2.13 1.05
2.44 1.31
.78 .39
0 .19
7.75 3.93
12.00 8.10
Other Ratios
East West
5.50
53.00 41.00
1.11
.47
1.11
10.70
.94
.48
1.25
-28-
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the finished lumber were totaled, they came to the 12.0' pbf shown.
However, three interviews provided direct data on log weights and
these three averaged 15. } pbf. But even these three individual
interviews did not total to the stated log weight when all itemized
waste streams were summed. The discrepancy is unexplained.
It may be considered notable that, the original log has 12.0 pbf in
the East and only 8.1 in the West. Two factors contribute to this.
One is that the pcf density of Southern pine wood is greater than
that of Douglas fir and ponderosa pine characteristic of the
Western lumbering. The other is that since the diameters are smaller
in the South than in the West the fraction of waste is greater in
the South than in the West, and accordingly, the number of cubic
feet required for one nominal board foot is greater in the South
than in the West. The projection of the total quantity of waste
for the two sections will be taken up when the disposition has been
explored .
5. DISPOSITION AND DISPOSAL
The disposition modes of both Eastern and Western wastes were
developed by computing the average percentage of each waste stream
going to the various disposition modes; in other words:
k
1 00 S" (P°un<^s waste type i to disposition mode j\
-|_ pounds waste type i ^
nk
where :
i = bark, sawdust, etc.
j = fuel, sold, TP, etc.
k = individual establishment
n = number of establishments
This summation and averaging was performed for ten Southern inter-
views and for fifteen Pacific Coast interviews with the results
shown in Table IV. In addition, forty-six Southern postcard responses
provided disposition and disposal data on the total waste at each
saw mill. This postcard data did not provide disposition and dis-
posal separately for each waste stream and could be used only in
computing the last row of Table IV.
The 1964 distribution of sawlog production was 34.4 billion bf , but
the distribution by region was not readily available. This was
approximated by using the regional proportions from 1962 from
Reference 4. This gave 14.4 bbfy (billion board feet per year) for
the East (South plus North) and 20.1 bbfy for the West (Pacific Coast
plus Rocky Mountain) . If it be assumed that disposition mode is
-29-
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West
East
TABLE IV
PERCENT OF EACH WASTE TYPE HAVING EACH DISPOSITION
SOLD FUEL GIVE AWAY TEPEE SELF DUMP NOT SELF DUMP OPEN BURN
o
i
Bark
Chips or Slabs
Sawdust
Shavings
Cut-Offs
Total Waste Including
Chips*
22
0
80
100
18
10
25
1
j 10
67
i
(
°
41
31
27
10
10
0
' 45
35
I 42
l
35
i 0
'. 0
'' 28
i 30
i
i
0
1
0
0
0
0
12
0
12
0
0
0
1.9
51 ;
l
f
48
10
0
37
16
33
16
33
0
31
26
i
0 i
25
0
0
0
17
0
17
0
0
0
8
1
0
o
0
0
0
0
0
0
0
0
0
.5**
0
17
0
o
.. ... . . !
!
0 j
10
0
10
0
L _ _° -
0
1.6
Weighed according to average proportions in waste.
Not self dump occurred only in the postcard responses for which we did not have data on separate
waste streams.
-------
independent of establishment size, and that the sample is repre-
sentative of the population then the disposition of total waste in
the two regions follows the percentages totaled in Table V. On
this basis, the non-sold, non-fuel, non-give away waste; that is the
waste of interest to the present project, becomes shown in Table ,
41,000 million pounds per year for the East and 24,500 million pounds
per year for the West. In the East about 3/4 of this is burned in
tepee burners.
TABLE V
WASTE DISPOSITION
East West
Non-sold, non-fuel, non-give away,
MPY (1964) 41,000 24,500
% Tepee 73.6 100
% Self Dump 20.6
% Open Burning 4.3
% Non-Self Dump 1.5
In the West, the interview sample indicates that it is all burned in
tepees.
It is of interest to compare these figures with those of Reference 4,
(Timber Trends) which was the result of an intensive study conducted
by the U. S. Forest Study and the State Forest Surveys and which has
been conducted at various intervals in the past. This work separates
waste types into coarse and fine, coarse being slabs, edgings, chips
and other material suitable for chipping while fine comprises
sawdust, shavings, and other material not suitable for chipping for
pulp manufacture. If it be taken that the nbf/cf in log is 5.6 in
both West and East, then the figures provided by Reference 4 for
total used and unused waste from all roundwood products as compared
with total production of all roundwood products would indicate a
volume percentage of waste of 36.3 for the East and 31.6 for the
West. These may be compared with the figures from Table III of 66 5%
for the East and 50.7 for the West. This discrepancy remains un- '
resolved.
Based on the values given for the unused portion of the waste
Reference 4 ad-justed to 1964, projects 24,600 million pounds per year
fo-r the East compared to the 41,000 million pounds per year of this
study. Furthermore, this study projects that the 41,000 million
pounds per year is entirely from the fine wastes since in the South
at least it was found that all the chippable material was being sold
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for pulp. It is possible that some of the discrepancy may arise
from coarse material unsold for pulp in the North as distinct from
the South. The comparison with the results for the West is better.
Reference 4 projects to 21,700 million pounds per year, adjusted
to 1964, compared with 24,500 from this study.
6. TRENDS
The trends in waste disposition in the saw mill industry are so
strong as to virtually defy projection of condition to 1975. Despite
the large quantity of unused waste still available and low recovery
of lumber from the log, the present condition already represents a
great advance over that of ten and twenty years ago. These advances
are still continuing. One of them was about to break upon the
South virtually at the time of the interviews. In the past, pulp
mills had not accepted sawdust and other fine residues because of
their short fiber length. Recently improved pulping processes
have allowed the retention of a longer fiber length from the con-
ventional materials roundwood and on chips and this allows the
incorporation of sawdust and shavings into the mix. Beginning in the
fall of 1966, contracts were being activated among the Southern mills
to dispose of sawdust as well as chips to the pulp mills. Since all
the chips are now being sold to the pulp mills and since nationally
wood chips provide only about 22% of the pulp requirements, it
seems quite clear that in the South where pulp mills exist in
proximity with saw mills there will be an opportunity to sell all the
shavings and sawdust as well as the chips for pulp. When that is
done, the shavings and sawdust now used for fuel will have to be re-
placed by bark with the result that the only waste then left will be
1.19 pbf of bark. If this switch should occur completely in the
immediate future such that the total production of lumber is still
applicable, it would change the 41,000 million pounds per year of
unused wastes to only 17,000 million pounds per year, all of which
would be bark. The growth factor to 1975 applied to this 17,000
million pounds per year generates 23,000 million pounds per year as
the projected Eastern waste in 1975, assuming that all chips, shavings
and sawdust will be sold for pulp.
In the West the situation is quite complicated. Western mills succeed
in using a greater percentage of their waste for fuel, and in selling
it. All forms of the waste are already sold. The interviews and
the general literature seem to give the impression that sale of chips
was not so successful in the West because of the lack of pulp mills
to take them. However, the actual interview data does not sub-
stantiate this since 80% of the chips are sold. A vigorous prospect
for taking more saw mill waste is particle board which can take
shavings and other hogged-down wood. Since the pulp market is far
from being saturated with wood residues as raw material and since
the demand for paper is increasing rapidly, it seems possible that
eventually the West will equal the East in the utilization not only
of chips but also of sawdust and shavings for pulp and particle board.
If that should occur, however, there would actually not be enough
bark now unused to replace the sawdust and shavings now used for fuel.
The result would be that, if this could be achieved, there would be
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no unused wastes in the Western saw mill industry. It is admitted
that this statement is based only on total quantities and does not
take into account the necessity for achieving the same balance in
each individual mill. However, it does represent what the trend
might be.
Incidentally, with respect to use for fuel there is an additional
distinction between Eastern and Western mills. In the East,
particularly in the South, natural gas is available and comparatively
cheap so that wood waste has a relatively low value for fuel. In
the West, however, gas is not cheap and the displacement of wood
waste by gas for fuel would be accompanied by a substantial increase
in the expense. Therefore, Western mills are not likely to divert
wood waste now used for fuel to other utilizations unless these
show a considerable profit. However, this is not of particular con-
cern to the particular study since the wood waste now used for fuel
does not enter the waste stream of interest anyway, i.e. to be
disposed.
Another development of direct interest to solid waste disposal is
the quite remarkable law passed by the state of Oregon, outlawing
tepee burners for wood waste because of the air pollution involved.
Since tepee burners are quite standard for disposal of wood waste,
this constitutes a drastic step for an economy so heavy in lumbering.
Existing tepee burners are allowed to continue operation, but no
new ones may be installed. If such a law is passed in the other
Western states, it would, of course, greatly accelerate the trend to
utilization rather than ultimate disposal.
7. SCOPE OF THIS STUDY
All of the codes covered in the present study are covered in a quite
cursory way, originally intended to be limited to only half a dozen
interviews in each code and a general description of the waste types
and problems. This condition is common to all codes and is mentioned
in the introductory material. However, it is given particular
mention in this chapter because of the existence of the extensive
investigation and report constituting Reference 4. This report was
produced by acknowledged experts and practitioners in the field of
forestry and lumbering aided by the state forestry departments who
are in close touch with the situations in their individual states.
While the details of the survey method and the data handling are not
fully stated in the report, it is obvious that a great deal of work
has gone into the study and the results should be authoritative.
The present study produces figures which in some cases differ from
those in Reference 4, but this does not by any means indicate that
the authors contradict the more extensive study. It is quite
possible that the Timber Trends study already has data in a form
which might be recomputed for the purposes of the present investigation.
In the other direction, possibly some of the needs and deficiencies
as brought out in the manipulations of the present study may be use-
ful in making some provision for such information explicitly in
future surveys for the Timber Trends series.
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SECTION VI
SURVEY RESULTS
B. SUPER MARKETS
1. CODES AND INTERVIEWS
The super markets interviewed were part of the retail grocery
S.I.C. Code 5411, but the interviews and projections were limited
to establishments having twenty or more employees. Such establish-
ments have about 568,000 employees or one half the total number
of employees in all retail grocery stores. Twelve interviews were
available, six from this project and six from previous projects.
2. WASTE TYPES
The meat wastes from super markets were practically all sold and
thus do not enter into the waste stream. The two types of wastes in
the stream were shipping wastes, almost entirely cardboard boxes,
and produce and sweepings. The cardboard averaged 75% of the waste.
3. WASTE QUANTITIES
There was no trend of the Kpye (thousand pounds waste/employee/year)
with number of employees. The ten available Kpye's were log-normally
distributed with a median of 25 and a a ratio attributable to the
population of 2.64. If the entire population of 16,000 establishments
with greater than 20 employees had these characteristics, the
average Kpye would be 40.7 and the 68% confidence interval is from
29 to 57. Applied to the 568,000 employees, this produces 23,000
million pounds per year of waste. The general disposition - disposal
study indicated that about 12% of this was given away, sold or
flushed to the sewer, leaving 20,310 million pounds per year as
waste for disposal, and in 1975, 26,400 million pounds per year.
4. DISPOSITION AND DISPOSAL
This was analyzed separately for the cardboard and the produce. The
disposition of cardboard was six contract, two give away, one sold
directly by the store, two incinerated at the store and two city
pick-up. The ultimate disposal means was three sold, four dump, two
incineration, one sanitary land fill and one unidentified. The
agencies were six city, two private and one contractor owned.
The produce disposition was five by contract, one give away and in
two cases it was being flushed to the sewer. The ultimate disposal
was three to the city dump, two city land fill and the two to the
sewer. The equipment used was trucks, packers and containerized
vehicles. Haul distances were of the order of four miles, but one
establishment was hauling twenty-seven miles one way.
-34-
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5. TRENDS
A definite trend was indicated toward a lower waste/product ratio.
Several establishments predicted that prepackaged food and better
preparation and preservation would significantly reduce the amount
of waste.
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SECTION VI
SURVEY RESULTS
C. COTTON GINNING
1. THE INDUSTRY
The cotton ginning industry has a number of unusual features. The
industry is, of course, confined to the cotton growing states in the
South divided into four regions the West: California, Arizona,
New Mexico and Nevada with about 20% of the production; the
Southwest: Texas, Oklahoma and Kansas with about 35% of the pro-
duction; the Delta states: Missouri, Arkansas, Tennessee,
Mississippi, Louisiana, Illinois and Kentucky with 33%; and the
Southeast: Virginia, North Carolina, South Carolina, Georgia,
Florida and Alabama with 12%. The leading state is Texas with 4,700
thousand bales in the 1962 1963 season, the major area being in
the High Plains and a lesser producing center in the Rio Grande
Valley. The next state is California with about 1,900 thousand
bales, followed by Mississippi with about 1,700 thousand bales, and
Arkansas with about 1,500 thousand.'
In the 1961 1962 season, there were 'about 5,400 gins in the nation
and the number has been decreasing each year. In 1964, it had
been reduced by about 200 gins.° The total bales ginned in the
1962 to 1963 season was about 15 million and thus, the average gin
had a production of about 2,700 bales. The distribution of gins
by bales ginned is approximately log-normal (a little less skewed)
with a median of about 2,150 bales/year and a a ratio of about 2.2.
Compared to other industries., the cotton ginning industry suffers
from a very low utilization factor on its equipment. In the first
place, cotton ginning is a seasonal operation limited to about twelve
weeks during the year in any one locality. The ginning season may
start as early as August 1st and end as late as January 15th, according
to the local climate. Incidentally, this means that the waste pro-
duction in any one location is concentrated in the twelve week season.
The time utilization of the plant is very low. The average hours per
year operated for nine gins in the interviews was 1,120 hours out
of the possible 8,766 hours in the year, about a 12.7% utilization of
time. Furthermore, not all of this time in operation is time in
production. It is not possible to call in a shift for less than eight
hours, so that when the cotton deliveries to the gin are not enough
to correspond to a fully day's production, the gin is not producing
during each operating hour. Furthermore, about an hour is consumed
in starting up and another hour in shutting down for cleaning. In
addition, breakdowns and delays due to poor weather further cut into
the production schedule. In nine of the interviews, the average
production rate was about six bales per operating hour compared with
an average capability in normal operation of about fifteen bales per pro-
ducing hour. Putting in the allowance for two hours per 24 hours for
-36-
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cleaning* this corresponds to a utilization factor of about 5.5%
on the total capability of the equipment. Since the investment for
a modern gin is of the order of $15,000 per bale per hour of capability,
it is evident that the cotton ginning industry operates with a
quite different philosophy of capital than does most manufacturing
industry.
SUB-CODES AND INTERVIEWS
Cotton ginning comprises sub-code 0712. Thirteen interviews were
available, conducted in Mississippi, Louisiana, and Texas and, in
addition, disposition information was obtained from three responses
to our postcard survey for Louisiana and Mississippi.
WASTE TYPE
The type of waste as well as the quantity thereof varies with the
method of harvesting the cotton. The classical method of harvesting,
picking off the seed cotton by hand, produces the least waste and
this waste consists of portions of the boll and occasional leaf
parts. Machine picked cotton is produced by mechanical adaptation
of this hand picking method and it may contain more leaf and a little
stem. Hand snapping comprises snapping off the stem and the boll
without attempting to pick out the cotton itself. This, of course,
produces additional waste components of stems and leaves. In machine
stripping, the plant is run through mechanical elements that strip
off some side branches, the leaves, stems, etc. Finally in machine
scrapping, the field is gone over a second or third time, producing more
trash.
The cotton delivered to the gin contains all of these above mentioned
elements as foreign matter plus the seed. In the ginning process the
cotton fiber itself is separated from the foreign matter and from the
seed. Some cotton fiber remains in the waste. When the ginned
cotton is further processed through a lint cleaner, some small pieces
of cotton occur as a waste to that operation. These are called motes.
If they are thus separated they are usually baled and sold for felting
material, etc. and thus are not considered in the waste stream in
this study. The quantity in any case is small .compared to typical
waste, something of the order of 12 to 15 lbs./500 Ib - bale of ginned
cotton. The remaining material is the "gin trash".
Its composition varies depending on the type of harvesting. With
some methods there may be as much as 500 Ibs. of dirt (i.e. soil) per
bale so that the overall gin trash would be about 50% mineral and 50%
vegetable. Of the vegetable material itself in machine stripped
trash the moisture content would typically run about 8% if the
harvesting is done before a frost and within ten days after a frost
would have fallen to 4% or less. Where defoliants are used and the
material is somewhat green, the moisture content may be 20 to 30%. The
bulk density is very low. With a small amount of dirt, it is of the
order of 5 Ibs./cu. ft.
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4. WASTE QUANTITIES
The weight of gin waste per nominal 500 pound bale of cotton depends
upon the method of picking. The weight of such a cotton bale plus
the seed associated with it is of the order of 1350 to 1450 pounds.
The difference between this weight and the total weight of cotton
delivered to the gin per bale produced represents the gin waste.
In the 1962 to 1963 season, the national averages of these gin wastes
per bale were:
Hand Picked 25 pounds
Hand Snapped 560 pounds
Machine Picked 110 pounds
Machine Stripped 770 pounds
Machine Scrapped 1,050 pounds
These weights, resulting from national statistics to be described
below, were approximately confirmed during the individual interviews.
The method used to project the total gin waste of the nation was as
follows. The U. S. Department of Agriculture supplies annual data^
on the number of bales ginned in each state, the percentage of the
total harvested by each of five methods in each state, and the
weight of raw cotton delivered to the gin per nominal 500 pound
bale for each harvesting method in each state. These figures were
manipulated as follows. From a number of sources, it was indicated
that the typical weight of gin waste in hand picked cotton was about
25 pounds per bale. By subtracting 25 pounds from the weight of
cotton delivered to the gin per bale in each state, there was obtained
a figure corresponding to the weight of cotton plus seed for each
state.
In one state the weight of raw cotton delivered to the gin per bale
was lower for machine picked than for hand picked and the 25 pound
procedure was applied to machine picked in that state. Subtracting
this base weight of cotton plus seed from the weights per bale for
each method of harvesting for each state then produced a set of data
on the gin trash per bale for each method of harvesting for each
state. This weight per bale, multiplied by the number of bales ginned
in each state produced the total gin waste for each state. This
totaled 3,836 million pounds per year for 1962 to 1963. Using the
disposal pattern described in the next section, the waste for disposal
is 1,572 million pounds per year; 1,432 million pounds per year of
it is burned.
The procedure for projecting the 1975 gin waste was as follows. There
are available back to at least the 1949 to 1950 season, similar
figures on the percentage of the cotton crop mechanically harvested in
-38-
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each state. A time series was plotted of this percentage for each
state and it was found that by 1975 all states will have 100%
machine harvesting. At present, machine harvesting comprises almost
completely machine picking in all states except Texas and Oklahoma
in which machine stripping is more prominent. Therefore, it was
taken that in 1975 all states except Texas and Oklahoma will have
100% machine picking and Texas and Oklahoma will have 100% machine
stripping.
To obtain the 1975 forecast for bales ginned in each state, a time
series was used starting about 1950 and an extrapolation was made.
It was quite general that there will be little trend in bales ginned
to 1975 judged by the performance of each state in the past fifteen
years. The gin waste per bale figures for 1975 were multiplied by
the projected gins baled for 1975 and summed to a projected total of
4,036 million pounds per year of gin waste in 1975. The disposal
pattern of 1965 - 1966, assuming that it is maintained, would indicate
waste-for-disposal at 1,665 million pounds per year.
5. DISPOSITION AND DISPOSAL
The disposal of gin waste is a major problem for the industry and is
being made more critical by the action of federal and certain state
regulatory agencies who are moving to control air pollution from the
common disposal method of burning. Because of this factor of state
regulation, which naturally varies from state to state and because
of the inherent geographical differences affecting waste disposal,
this subject warrants a full scale study in itself and cannot well
be covered as one among twenty industries in this preliminary survey.
Indeed, a number of such studies have been made and there is considerable
activity on the part of the ginners, the ginners associations, the
regulatory agencies, and equipment manufacturers, as well as the
experiment stations and the U. S. Department of Agriculture.
Because the problem is so difficult, ginners who are able to sell or
give away the waste may be considered fortunate. In one of the
thirteen interviews and postcards, the gin waste was sold for a
nominal price of $1.50 - $2.50 a ton to growers who incorporated
the material in the soil as an organic amendment. In two other
cases, some or all of the gin trash was given away for the same pur-
pose, one of these being to the farm of the gin owner. One gin was
considering a commercial operation in which the waste would be
pelletized and fortified for cattle feed being a complete feed including
roughage.
Since there have been no really likely suggestions for economic
utilization of the waste, it would seem that the best disposal at
present would be as a soil conditioner. However, there are some
objections even to this. One interviewed gin would welcome such a
use, but refrained from exploiting it because it would involve storing
the waste while waiting for the farmers to come and get it at their
leisure, and presumably well after the ginning season. In the
Mississippi Delta region use as a soil amendment is not practiced
-39-
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partly because they have there a campaign to eradicate weeds from
the cotton fields and the return of the waste to the fields would
interfere with this program. Storage of the waste is not desirable
since because of its low bulk density a large space is required and
because of its low real specific gravity it is easily blown around
the countryside by the wind.
For the same reason, it has some disadvantages as a soil amendment
since in order to be maintained on the field it must be plowed in.
This has led to some experiments being conducted by some interviewed
gins in composting the waste in pits to reduce its volume and increase
its density and resistance to wind blowing.
For the most part then, the ginner is on his own in the disposition
and disposal of the waste and this is indicated in the interviews.
In one of the twelve interviews the ultimate disposal was to a city
owned dump. In the remaining eleven it was to a self-owned burner
or incinerator. Gin trash, fresh from the gin, is readily burnable.
However, its low bulk density requires a high volume of the fire
bed and its low actual specific gravity requires low velocities in
the overhead space to avoid blowing the burning material and ash
out the stack.
Numerous devices for accomplishing this burning have found favor in
the ginning industry, on the basis, one-gathers from interviewing
the field, of being the lesser of other possible evils. Cheapness
is a primary consideration, and there are probably very, very few
sophisticated incinerators specifically designed to avoid air pol-
lution in the industry. None were found in the interviews. Among
types of burners encountered were tepee burners, jug burners (masonry
structures with a stack on top which looks like a wine jug), and
simple pits in the open surrounded by a corrugated iron fence.
There are signs of considerable activity at the grass roots level to
develop superior burners, but so far none of the regular equipment
companies supplying this market seem to be interested. Presumably
a likely type of manufacturer for such incineration equipment would
be the cotton ginning equipment manufacturers who have the close
contact with the market, followed by the incinerator manufacturers
themselves, or possibly in conjunction therewith.
Air pollution results from chemicals used on the cotton for growing
and harvesting purposes. Arsenic containing insecticides appear
in the waste and arsenic compounds, being volatile, issue in the flue
gas as a fume. These poisonous fumes carried downwind can be an
actual health hazard and it is for this reason that the health depart-
ments and air pollution control departments of some states are
vitally concerned. In the Mississippi Delta it is not the usual
practice to use arsenic compounds for boll weevil control. Instead,
methylparathionate is used to the extent of about 85% and Sevin about
15%. These are evanescent materials which even applied on the plant
last -only a few hours. Malathion is not used to any extent because
it is more expensive than these. With such growing practices,
presumably the hazardous type of air pollution would not occur. How-
ever, on the Texas High Plains, arsenic compounds are commonly used
and the air pollution situation there is mounting.
-40-
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The foregoing provides some illustration of why the cotton gin waste
problem is so complicated, depending as it does so much on the
technological, geographical and climatological aspects of the
growing, the harvesting, and even the merchandising of the cotton.
There recently became available10 an extensive survey
comprising a 100% sample of the cotton gins in the nation during the
1965 - 1966 season indicating the per cent of gins in each state
which burn their wastes, which return the waste to the land, and
which have other disposition modes. The 100% sample can be used in
obtaining an accurate figure for cotton gin waste for disposal. To
each of the state totals for total gin waste there was applied the
three percentages from the 100% sample, thus giving the Kpy the
waste burned, returned to the land, and having other disposition for
each state. The overall national average for the United States
was 37.3% burned, 59.0% returned to land, and 3.7% other disposition.
The figures given in the quantity section of this chapter result
from that computation. A separate study from project data indicated
that the disposition pattern for motes was quite similar to the
above with the percentage returned to land becoming percentage sold.
Motes averaged, in the sample, 8.5% of the total waste.
The quantitative changes in the disposition pattern by 1975 cannot
be predicted, but if there is no change in disposition pattern in
each state, a similar procedure projects that the disposition of the
1975 waste would be 37.8% burned, 58.4% returned to the land and
3.8% other disposition. If one must hazard a guess as to the
qualitative changes in disposition pattern by 1975, it would be that
the pressure on air pollution control will substantially reduce the
amount burned and increase the amount returned to land and to other
disposition modes.
6. TRENDS
Something of the expected trends have already been made evident
through the 1975 projection method used. There is an increasing
trend to machine harvesting already evident from the historical data.
Another trend to be provided for, though not explored here, is the
use of defoliants prior to harvesting. This, affects both the com-
position and quantity of the gin waste. Trends in gins baled as
shown by the state statistics are not great. However, within smaller
regions than defined by state boundaries extensive changes may
occur. Based on the interviews in the Rio Grande Valley of Texas
it may be expected that the cotton production of the Valley will
decrease markedly in the next ten years. Overlying the entire trend
picture are the inroads on cotton made by the synthetic fibers and
the inroads on domestic cotton made by imported cotton. These
subjects are considered beyond the scope of the preliminary exploration.
In the interviews, various technological changes were mentioned as
bearing on the waste trend, but it was not possible to integrate
these into a total picture. It is quite certain that the productivity
(product/employee ratio) will increase in ginning due to the continuing
-41-
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introduction of automatic machinery. Even the method of planting
can affect the waste picture. For example, in one area it was
thought that broadcast seeding (in distinction to row seeding)
would become major. This would increase the difficulty of weed
control and work against use of the waste as soil amendment. Like-
wise, it would increase the incidence of machine stripping which
would increase the waste per bale. In some areas a machine (the
Rood) scavenges the cotton dropped to the ground during the regular
harvesting. This machine will have a very high waste per bale ratio
because of the dirt picked up with the cotton. Another development
in just the opposite direction is the Logan machine, now being
manufactured by one of the ginning equipment companies which cleans
the cotton in the field. This, of course, would greatly reduce the
waste per bale ratio. In disposal, the most likely trend is that the
fraction burned will decrease as a result of the pressure of air
pollution control.
-42-
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SECTION VI
SURVEY RESULTS
D. DEMOLITION
1. THE INDUSTRY
The general method for demolition was to interview one of the more
prominent wrecking companies in the city to obtain answers to the
general questions on waste disposal. The quantity of waste developed
in this interview was converted to Kpy and the interviewees estimate
of the percentage of the total business which he had was used to
project the total for the city. Care was taken to determine the
boundaries of the territory served. If we were fortunate enough to
choose one of the larger wreckers in the city, he was asked to name
a few of the next larger ones. Then the next largest was approached
for a brief interview to confirm the general questions as to
disposition, disposal, etc. and similar questions were put concerning
the waste quantity and per cent of the total business enjoyed.
This served as a check on the prior projection. The population of
the area served was projected to 1966 by multiplying the percentage
increase 1950 to 1960 by the 1960 census population, giving a pro-
jected increase for 1960 to 1970. Six-tenths of this was taken as
the projected increase, 1960 to 1966 and added to the 1960 census
figure to obtain 1966 estimate. The Kpy was divided by this 1966
population to develop a waste ratio in units of thousand pounds per
year per capita (Kpyc).
The following example is given to show the nature of the computations
in detail. The confirmation between the two interviewees came out
better than for most cities interviewed. Wrecker C stated he did
80 to 90% of the business in the city. He estimated his waste in
two categories, Type One consisted of lumber, stucco, wire, etc.
from demolition of frame buildings of which he produced 250 thirty
cubic yard cans per month. These "cans" were hauled away on trailers
and in connection with a study of a larger size can, he had recently
determined that 15 tons could be hauled in a can 8 x 8 x 30 feet.
This computes to 68 cubic yards (cy) per can or a bulk density of
0.442 thousand pounds per cubic yard (Kp/cy). The other type of
waste, Type Two, was from brick and masonry buildings and this pro-
duced about 1.5 loads per 1,000 brick handled at about 4.5 cy/load.
This computes to 6.75 cy/Kbrick and further discussion produced an
overall estimate of 6 to 10 cy/Kbrick. An average of 7.0 was taken.
In addition to this, there was a quantity equivalent to about one-third
of this from small non-brick buildings. This waste was of a masonry
rubble type and the interviewee confirmed a figure which had been
obtained from one of the municipal interviews (Los Angeles) of a
bulk density of about 1.8 Kp/cy. The waste generation of Wrecker C
computed from these data is described in Table VI.
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TABLE VI
WASTE GENERATION OF WRECKER C
% Bulk
Kpy % Wt. Basis cy/yr. Basis kp/c^
Type One 39,700 20 90,000 94 .442
Lumber
Stucco
Wire
Type Two 16,800 30 9,300 6
56,500 99,300
A subsequent interview with Wrecker R stated by Wrecker C to be the
Number 2 operator indicated that in previous years Wrecker R had
enjoyed 45 to 50% of the business, but that in the past year or so
they had only done 10% of the total city business. This amounted
to 45 to 50 cy/day on a five day week basis. He also confirmed
that Wrecker C did indeed handle upwards of 90% of the total
business. A bulk density was not obtained in this confirmatory inter-
view, but for computation, it was taken that bulk density of the
overall waste of Wrecker R was the same as that of Wrecker C, namely
0.57 KP/cy. At 45 cy/day this computes to 6,660 Kpy which happens
to be just 10.6% of the city total as computed from the data supplied
by Wrecker C.
When this total city Kpy was divided by the estimated 1966 population,
there was obtained a waste/population ratio which conformed well
with the geographic pattern of the other waste population ratios for
other cities.
2. WASTE TYPES
Demolition waste may be divided into two waste classes. Frame houses
produce a waste comprising wood, stucco, metal lathe, etc. which is
generally regarded as a combustible waste though not conventionally
incinerateable. The bulk density of this material is of the order
of 350 to 450 Ibs./cy. In a recent set of experiments exploring the
use of an 8' x 8' x 30' container for demolition described as lumber,
stucco and wire, the cans were found to hold about 15 tons. This
computes to 442 Ibs./cy. However, a 22' can could contain only
6 tons, a bulk density of 230 Ibs./cy. The difference lies in the
fact that the 30' can is big enough to take the large pieces of lumber
lying flat, while the smaller can accepts them only at an angle,
thus wasting space. Another interview provided a bulk density of
328 Ibs./cy in 55 yard trucks. This type of waste contains two-thirds
to three-quarters combustible matter, i.e. wood, roofing, etc. The
term "combustible" is applied to this waste as a whole when it is
necessary to segregate types of wastes in order to assess charges at
land fills, etc.
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The second type of waste is termed "non-combustible" and is indeed
non-combustible, consisting of bricks, masonry, rock, concrete,
rubble, etc. resulting from the demolition of masonry buildings and
of the foundations and slab floors of frame buildings. Weighing
experiments on such waste show very high bulk densities, some as
high as 1,800 Ibs./cy.
The ratio between the two types of demolition waste varies greatly,
depending on the type of construction which is typical of the city.
In the one city already cited as an example, the non-combustible
portion was only about 10% of the total. In another city where
brick and masonry construction is common, the non-combustible was
80% of the total.
The quantities of total demolition waste computed as above frlom seven
interviews for the six cities were:
Pounds Per Year
Per Capita
(not kilopounds)
230
62
12
22
173
Data Not Available
In addition, similar data were available from prior projects on
seven cities geographically spread from border to border and coast to
coast. On the basis of these twelve data points, assignment of
round number pyc's (pounds per year per capita) was made to each of
the 48 states and these pyc's were assigned to each SMSA (Standard
Metropolitan Statistical Area) in the state. If the SMSA or SCA
(Standard Consolidated Area) lay in two states with different pyc's,
it was assigned to the state with the larger pyc. These pyc's
were then applied to the 1966 and 1975 estimates of the populations
of the SMSA's or SCA's and the products summed over all areas.
Thus, projected in round numbers, the 1966 demolition waste is
38,100 million pounds per year and the 1975 waste assuming no trend
in pyc's in the interval is 44,300 million pounds per year.
3. DISPOSITION AND DISPOSAL
Disposition of demolition waste is almost entirely by the demolition
contractor himself, and indeed is an integral part of the demolition
operation. In thirteen interviews conducted over the past several
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years, only one instance was found in which a demolition establish-
ment occasionally used contract disposition. Truck sizes used in
disposition run from 4 1/2 to 55 cubic yards. The container
system is also used in 10 and 52 cubic yard sizes and in one experi-
mental development in a 68 cy size. The haul distance, of course,
varies with the location of the demolition job, but in general does
not average less than ten miles and in some cities up to forty
miles. The round trip time may be anywhere between forty-five
minutes and four hours.
Salvage used to be an important part of the disposition and disposal
picture for demolition waste. However, with the increasing cost and
scarcity of semi-skilled labor and the increasing cost of insurance
(for the warehousing phase of salvage), salvage has passed out of
the picture in highly industrialized regions and southern cities
are just now going through the transition to the non-salvage style
of demolition. As an example, in one city it formerly took a six
man crew one and one half weeks to demolish with salvage a five room
house. Abandonment of this method was forced by labor conditions
and it now takes only one day to demolish a similar house by machine
methods. The machine method consists of using a clamshell derrick
which literally demolishes the house by taking bites out of it and
depositing the bites in the waiting trucks. This trend is greatly
increasing the waste generation in those cities in the transition, but
it is believed that this transition is about over for the bulk of
the cities in which demolition is occurring.
Air pollution ordinances are also overtaking the demolition industry.
Formerly it was the practice to "clam shell" a building, depositing
the combustible waste on an adjacent vacant lot where it was burned
on the site. Pollution or safety ordinances are forcing abandonment
of this practice. In one northern city the banning of open burning
has forced demolition contractors to haul waste as much as forty
miles for disposal. This has doubled the cost of demolishing frame
houses. In another city there is no ban on open burning, but there
is an ordinance prohibiting burning within 200 feet of a structure
which effectively prevents burning of demolition waste on site. In
one city, where air pollution is acknowledged to be a problem which
must be faced in the near future, one of the interviewed demolition
contractors had considered incineration, but decided against it on
the basis that in his opinion air pollution ordinances would prohibit
incineration within two years.
Ultimate disposal is almost entirely in dumps or sanitary land fills.
The Type Two waste is acceptable at any dump and thus is associated
with the shorter haul distances. In addition, Type Two waste has
value as fill at various points in the metropolitan areas at which
leveling and construction is planned. It is more difficult to arrange
ultimate disposal for the Type One waste due to the combustible
material and to the bulky nature of the waste. Practically all the
disposal is in dumps or sanitary land fills, but in one city it has
been the practice to barge some out to sea. Open burning of
demolition waste on open dumps is rapidly on the way out. The ultimate
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disposal facility may be operated by the municipality, by the
demolition contractor himself (private as defined), or as a merchant
facility. Among fifteen interview responses, the incidence was
seven municipal, four merchant, two not self (merchant or municipal
not determined) and two private. In other words, only one in seven
was private.
TRENDS
It is obvious from the interviews that the demolition industry faces
a major problem in waste disposal. The disposal of the masonry
rubble Type Two waste is not difficult since it can be used for
clean fill which is always needed in a metropolitan area. The problem
is with the "combustible" Type One waste. Not only are the haul
distances to existing dumps becoming too great, but also existing
dumps and sanitary land fills are becoming more restrictive on the
inclusion of the large pieces of wood generated by demolition.
Furthermore, this type of waste contains many bulky items such as
pipe, bathtubs, sinks, etc. plus a considerable amount of non-
combustible material such as wire, stucco, plaster and this makes
it difficult for incineration. Segregation of the bulky items and the
non-combustibles from the Type One waste is out of the question
because of labor costs which indeed even prevent the salvage of these
items and the wood itself as saleable materials.
Incineration seems to be the only possibility of a solution to the
problem, but required is the development of a specialized incinerator
to handle such wastes. In several interviews there was mentioned
the desirability of a portable incinerator which would satisfy air
pollution requirements, handle the waste type and also be movable
from one demolition site to another. This seems to be an opportunity
for needed research and development.
There does not seem to be anything in the general economic trend
which would reduce the amount of demolition per capita in the next
ten years. The quantity of waste will probably increase somewhat in
those cities which now have a comparatively low waste per capita
ratio, since it is in general in these cities that the transition is
in progress from hand demolition to machine demolition. This transition
has already occurred in the region of the country where most of the
demolition occurs, and thus the overall effect will not be large.
The industry faces a major problem in finding dump or land fill sites
which are close to the work. It will undoubtedly be impossible to
locate these and haul distances will increase substantially. Attempts
are underway (some confidentially revealed during the interview
campaign) to develop better methods of handling and segregating the
Type One waste and of incinerating it.
The demolition industry is one of the few industries that does not
have a national trade association. Such an association through its
activities and through the pooling of techniques and experiences
would probably be very helpful in this phase of the industry's problems.
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SECTION VI
SURVEY RESULTS
PAPER
1. SUB-CODES AND INTERVIEWS
S.I.C. Code 2611 comprises pulp mills not associated with paper
mills. There are only about fifty of these in the nation, and it was
felt that their solid waste production would be relatively small,
so this code was not interviewed or included in the projections.
The remaining sub-codes of interest, together with the number of
employees and the number of interviews, are as follows:
Code Description Employees Interviews
2621 Paper mill ex. building paper 133,000 6
2631 Paperboard mills 67,000 11
264 Paper & paperboard products 166,000 5
2651, 2, 3 Paperboard boxes 7
2654, 5 Corrugated and fiber boxes,
sanitary food containers 2
265 (All Sub-Codes) 191,000 9
266 Building paper and board 12,000 1
Six interviews were conducted on the current project, but a total of
twenty-six other establishments were available from previous inter-
views in a total of twenty-nine interviews.
2. WASTE TYPES
Some paperboard mills start with logs as raw material, but some
start with waste paper. Those that start with logs and the paper
mills which quite universally start with logs, have waste bark which
is used for fuel. In general, in paper making and paper converting
operations, the waste paper itself can be repulped or is saleable
as paper scrap. However, in manufacturing certain kinds of paper
the waste is not saleable. These include wet-strength papers, coated
papers, waxed papers such as from sanitary food containers, paper
products containing metal inserts such as juice cans, and treated
paper of various kinds. Establishments handling these kinds of papers
have more waste than those handling papers which can be repulped or
sold. Paper establishments have plant trash and shipping wastes.
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The wastes contain some metal from staples used in box manufacture,
from metal strapping comprising a portion of the shipping waste,
and the metal portions of metal insert containers.
3. WASTE QUANTITIES
There was no trend of KPYe's with size. In earlier work there
seemed to be some reason, based on the technology of the sub-codes,
for separately considering certain paper sub-codes. Accordingly in
the present study the 32 available Kpye's were analyzed in five
groups comprising the sub-codes 2621, 2631, 264, 2651, 2 and 3,
and 2654, 5. The log normal distributions of these had similar a
ratios. Group 2651, 2 and 3 had the lowest mean and the groups
comprising 2621, 2624, and 2654, 5 had means relatively close
together and high. A test was run for the significance of the
difference of the 2651, 2 and 3 mean from the means of the three high
groups, with the result that there was no significant difference at
the 5% level. The remaining group being between these two it was
concluded that the code could just as well be represented by a
single distribution. This log normal distribution of 32 Kpye's
had a median of 8.64 and a a ratio of 3.55. If this is characteristic
of the population of about 5,000 establishments, the average Kpye
would be 19.4 and the 68% confidence interval thereon would be from
15.5 to 24.4.
As will be shown in the distribution section, it is estimated that
10.6% of the total waste constitutes that utilized for fuel or sold.
Thus, only 89.4% of this total is subject to ultimate disposal as
a waste and the corresponding average Kpye is 17.3.
A corresponding figure was computed by another route primarily to
test whether the dispersion might not be better if the Kpye's were
computed in terms of the non-fuel non-sold waste. These numbers
may be used, however, to project another figure for the average,
which, if the population had those statistical characteristics, would
be 16.1, a close check with the 17.3 obtained via the total waste
and disposition route. This average applied against the total
number of employees in the paper code excluding pulp mills 2611,
projects to 9,950 million pounds per year in 1965. With the growth
factors this predicts 14,700 million pounds per year in 1975.
4. DISPOSITION AND DISPOSAL
Disposition was by Dumpsters, dump truck and front end loaders. Haul
distances average three miles with a maximum of seven in the inter-
views. Out of the thirty-two establishments, four sold some or all
of their waste and two utilized some for fuel. Among these six, the
average percentage used for fuel or sold was 78.5%. If this
disposition mode is independent of size and the sample is representative
for disposition, the fraction of the total waste sold or used for
fuel would be 14.7%. Of the remaining disposition situations,
including the postcard responses, thirty were by self, thirteen by
contract, one by city pickup and two unknown. The ultimate disposal
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facility ownership was twenty-three self, thirteen city, eleven not
self, but unknown. The disposal method was twenty-five dump, four
sanitary land fill, three open burning, seven incineration and nine
unknown.
TRENDS
A few plants indicated they were attempting to reclaim more fiber,
but since fiber (as sludge from settlers) was a very small amount
of the total waste, this cannot bring about any trend. No other
trends were evident from the interviews.
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SECTION VI
SURVEY RESULTS
F. FOODS
1. SUB-CODES AND INTERVIEWS
Previous studies had been made in the food sub-codes of cereal
preparations, poultry processing, rice milling, bakeries, sugar,
coffee and meat packing. Meat packing appears as a separate chapter
in the present report. The other sub-codes treated separately had
such small amounts of total waste that they were not chosen for
industry coverage in this report. The food industry is highly
heterogeneous and it would be impossible to cover every sub-code in
it. The seven interviews were in sub-codes 2033 canned fruits and
vegetables, 2021 butter, 4 ice cream, 5 dairy products, 2082 beer
and 2099 miscellaneous food specialties. The projection was based
on all food sub-codes excluding the seven sub-codes mentioned in
the first sentence above. This group has 1,030,011 employees which
is about one-third less than the number of employees in the entire
two-digit code.
2. WASTE TYPES
The waste types were plant trash, shipping wastes, and process
wastes characteristic of each product process. Where distinguishable,
the process was about two-thirds of the total. The shipping wastes
included cardboard boxes and metal cans.
3. WASTE QUANTITIES
The waste quantities were based only on the six Kpye's available from
the seven interviews in the current project. There was no trend
with employment size and there were not enough interviews in any one
sub-code to make distinctions between sub-codes. Kpye's were
log-normally distributed with a median of 6.0 and a a ratio of 3.17.
If these are the characteristics of the population of 27,000 establish-
ments, the mean Kpye would be 11.6 and the 68% confidence interval
from 6.7 to 20. Applied against the number of employees in the pro-
jected sub-codes (excluding the seven mentioned) this gives 11,346
million pounds per year. Adjusted by the results of the disposition
and disposal analysis, the waste for disposal is 10,584 million
pounds per year. At a growth factor of 1.33, this projects to 14,076
million pounds per year in 1975.
4. DISPOSITION AND DISPOSAL
The disposition and disposal data described here arises from the
seven interviews on this project plus seven additional interviews
from earlier projects. Disposition is by truck, dump truck and
containerized trucks, five self, nine contract and one city. The
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ultimate disposal method was five dump, three incinerator and three
sanitary land fill and four uncertain, probably dumps. Ownership
of the ultimate disposal facility was three self, four city and one
not self.
5. TRENDS
The interviewees did not expect any trends in waste/product or
waste/employee ratios.
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SECTION VI
SURVEY RESULTS
G. WOODEN CONTAINERS
1. SUB-CODES AND INTERVIEWS
The sub-codes making up 244, Wooden Containers, together with the
number of employees and the number of interviews available are as
follows:
Code Description Employees Interviews
2441 Nailed wooden boxes and shook 13,653 8
2442 Wirebound boxes and crates 9,713 6
2443 Veneer and plywood containers 3,498 0
(except boxes)
2445 Cooperage 2,872 1
An industry very similar to the wooden container industry, i.e.
starting from the same raw material, comprising very similar operations
and having quite comparable waste quantities, is the manufacture
of wooden pallets. Some of the establishments interviewed manu-
factured pallets along with wooden containers of various types.
There is considerable heterogeneity in the industry which actually is
not reflected in the observed dispersion of Kpye's among the codes.
Basic to the lumber and wood products industry is the distinction
between those establishments which start from logs as raw material,
and those which start from lumber already manufactured from logs.
Both types of establishments are found in the sub-codes of 244.
Using 2442, wirebound boxes and crates as an example, a typical
establishment is a combination of a saw mill, a veneer mill, and a
box assembly plant. The saw mill produces the cleats for the ends
of the veneer boxes. The veneer mill produces the veneer for the
sides and the box assembly plant assembles these two items into the
finished box. All establishments interviewed had the veneer mill,
but some of them did not have the cleat mill, purchasing cleats from
another source. A typical ratio of mbf (million board feet) feeding
the cleat plant to mbf feeding veneer plant is about 0.7.
As a result of the interviews and a subsidiary postcard survey there
were available twenty-eight productivity figures for establishments
in Code 244, in terms of Kbfye (thousand board feet per year per
employee). These productivity ratios were log-normally distributed
with a median of forty-two Kbfye and a a ratio of l.'Sl. The pro-
ductivity is about one-fourth that in saw mills.
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2. WASTE TYPES
The waste from wooden container manufacture is similar to saw mill
waste but includes more dry wood from the veneer mill and the box
plant. The saw mill portion, of course, produces wastes entirely
similar to lumber manufacture in saw mills. The veneer plant
portion has waste characteristic of veneer production. Round-up
waste (green wood) occurs in the first cuts on the rotary lathe
rounding up the log cylindrical with the lathe axis. It includes
both bark and the outside layers of wood. The residual cylindrical
core, also green wood, may appear as a waste directly. However,
it is not uncommon to use these cores as raw material for manu-
facturing 2 x 4's (studs) and quite common to chip the core or
the residual from stud manufacture into chips for sale to pulp
and paper mills. The waste cuttings from manufacturing the siding
elements from the raw veneer are dry wood. In addition, the box
assembly portion of the plant produces reject boxes, etc.
3. WASTE QUANTITIES
As will be indicated from the disposition survey, it is almost
universal to sell chips from wooden box manufacture for pulping.
Accordingly, the chips described as wastes have been eliminated from
the waste stream computations hereafter. There is no trend of Kpye
with sub-code or with employee size.
The fifteen Kpye's are log-normally distributed except for the
lowest three which occur at lower Kpye's than corresponds to their
percentile levels. The median is 66 Kpye and the a ratio 3.18. If
these are the characteristics of the population of 904 establishments
in the projected codes the average Kpye would be 125 and the 68%
confidence interval from 91 to 172. Applied against the total of
some 29,000 employees in the projected codes this gives 3,717 million
pounds per year for the non-chip waste. However, the disposition and
disposal study showed that a certain fraction of the interviewed
establishments are able to dispose of some or all of the non-chip
waste without cost to themselves, i.e. either by giving it away
or by using it for fuel. Portions thus handled do not enter into the
industrial waste stream and when this correction is made the projected
non-chip waste for which free disposition is not available becomes
2,380 million pounds per year. In the disposition - disposal analysis,
a new Kpye including chips was used against which was applied the
pattern including chips. The result was 2,470 million pounds per
year which was chosen. Applying the growth factor (which for this
industry is less than 1.0), this becomes 2,190 million pounds per
year projected for 1975.
4. DISPOSITION AND DISPOSAL
For the disposition study there are available data of two different
types which were first considered independently. One of these is the
information from the fifteen interviews and the other is information
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from a postcard disposition survey previously made comprising twenty
five responses. Of the fifteen interviews, seven incinerate all^
their waste and one open burns all his waste. These eight comprise
53% of the establishments. Four out of fifteen, or 27%, dispose of
all of their waste without cost to themselves by giving away or use
for fuel. The wastes of these establishments therefore, do not
enter into the industrial waste problem. Three out of fifteen, or
20%, dispose of about 50% of their waste without cost to themselves
and the other 50% they incinerate. These data refer to numbers of
establishments, but if it be assumed that these ratios are independent
of establishment size (measured by total waste production), then
these percentages likewise become the percentages applicable to the
disposition of the waste produced. With this assumption, these data
indicate that 37% of the waste is disposed of without cost to the
producer and thus does not enter into the industrial waste problem
while 63% of it requries an expenditure for disposition and disposal.
Similar information is available from the postcard survey. The check
between the two sets of data is quite good. Three out of the
twenty-five (compare three out of fifteen) have more than one type of
disposition and in each case, half was disposed of without cost to
the producer and half by disposition involving expenditure. Thirty-two
per cent of the waste was disposed without cost to the producers
(compared 37%). Sixty-eight per cent (compare 63%) incurred a cost.
Since these results are in conformity with each other, the data may
be combined whereupon, based on the assumption above, it may be
projected that about 30% of the non-chip waste find free disposition
(nearly always for fuel). About 58% are disposed with some expense
to the producer, nearly all burning in some form and mostly by
tepee burner. The remaining 12% is about half free disposition and
half not free. In summary, 70% of the establishments have a waste
problem and among these establishments, about 8% of the waste is
disposed of wihtout cost to the producer. Over all, about 36%
of the waste finds free disposition and the remaining 64% constitutes
an expense to the producer.
In all cases, the disposition is by self for the non-sold non-fuel,
non-give away waste. It is to be noted specifically that no
instances of contract disposition or city pickup were found. The
ownership of the ultimate disposal facility was in each case the
producer, and the type as qualitatively indicated above.
5. TRENDS
No evidence of any general trends were observed in waste/product or
waste/employee ratio. However, as has been described in the saw
mill chapter, it is imminent, in the South at least, that sawdust is
to become utilizable for pulp. If this is the case for saw mills it
will very likely also be the case for wooden container manufacture
starting from logs, since these also sell chips to the pulp mills
Unfortunately, an exact quantification of the fraction of wooden
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container waste which is sawdust is not available to the project,
but such approximate data as are available suggest that sawdust may
be of the order of 30 to 40% of the non-chip waste. Accordingly,
if sawdust becomes saleable to pulp mills, the total waste will be
reduced by this amount.
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SECTION VI
SURVEY RESULTS
H. WOOD FURNITURE AND FIXTURES
1. SUB-CODES AND INTERVIEWS
The sub-codes involving wood furniture, together with number of
employees and number of interviews incorporated in this chapter, are
as follows:
Code Description Employees Interviews
2511 Household ex. upholstered 141,000 7
2512 Household, upholstered 69,000 5
2519 Household (not elsewhere 2,000 0
classified)
2521 Office 6,000 1
2531 Public building 18,000 1
2541 Partitions, fixtures 23,000 2
2599 N.E.C. (not elsewhere 8,000 0
classified)
Of the sixteen interviews, six were on this project and ten were
available from previous projects.
2. WASTE TYPES
The types of waste occurring are plant trash, shipping waste and process
waste. The process waste consists of sawdust, shavings and wood
scrap, upholstery materials, oily rags, styrofoam, sandpaper and
abrasives. No data were available on the various proportions of
these.
3. WASTE QUANTITIES
The twelve Kpye's are log-normally distributed with a median of 3.0
and a a ratio taken as corresponding to the population of 6.0.
There is no trend in Kpye with sub-code or employee size. If this
is the characteristic of the entire population of 6,800 establish-
ments, the average Kpye would be 14.6 and the 68% interval from 8 1
to 26.2 Kpye.
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A certain portion of the waste is used as fuel, sold or given away,
in other words, it is disposed of without cost to the producer,
and therefore, not considered as entering a waste stream. The
general disposition - disposal study gave the waste entering the
final waste stream as 79% of the total waste represented by the
Kpye's. Applied to the total number of employees, this gives 3,090
million pounds per year of waste in the ultimate waste stream. The
physical production ratio to 1975 is 1.67, thus projecting the
1965 waste quantity at 5,170 million pounds per year.
4. DISPOSITION AND DISPOSAL
The data given following, includes both the ultimate waste stream
and the 18% disposed fuel, sold, or given away. Disposition was
by truck, thirteen self, two contract, one city, three fuel, three
sold and three give away- Ultimate disposal was seven incineration,
six dumps, one sanitary land fill and one open burning. Ultimate
disposal facility ownership was seven private, being the incinerators
and nine city.
5. TRENDS
There is no major trend in waste/product ratio. One establishment
indicated that more of the sawdust would find a useful outlet in
particle board and composition board and one establishment indicated
that there was trend in shipping waste away from wood and to cardboard
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SECTION VI
SURVEY RESULTS
I. AUTO AND AIRCRAFT MANUFACTURE
1. SUB-CODES AND INTERVIEWS
The sub-codes covered in this chapter are 371, motor vehicles and
motor vehicle equipment with 620,000 employees and 372, aircraft
and parts with 740,000 employees. The interviews were drawn from
sub-codes 3711, 3712, 3714, 3721, 3722 and 3729. Six interviews
came from the present project and two were available from prior
projects. Three interviews were in Code 371, four in 372 and one
in both codes.
2. WASTE TYPES
The major types of waste are plant trash and shipping wastes, the
latter containing considerable wood. Only four out of the eight
interviews had any process waste and the percentage of these wastes
in the total was very small.
3. WASTE QUANTITIES
The Kpye (thousand pounds of waste/year/employee) for the eight
interviews showed no differences between the two three-digit codes
and tested statistically at the 5% level of significance showed no
significance to the correlation with number of employees. The
Kpye figures were log-normally distributed with a median of 0.90
and a o ratio taken to correspond to the population of 4.0. If
this is the characteristic of the entire population of some 4,000
establishments, the average Kpye would be 2.34 and the 68% interval
from 1.4 to 4.0 Kpye. Applied against 1,361,000 employees in these
two three-digit codes, this projects the total waste to 3,180
million pounds per year. The general disposition - disposal study
indicates that about 8% of waste is given away, so that waste-for-
disposal is currently 2,910 million pounds per year, and in 1975
3,660 million pounds per year.
4. DISPOSITION AND DISPOSAL
Of the eleven disposition situations, six were by contract, four
private and one by city. Metal scraps and shavings were generally
sold, but no major portion of the waste was sold for salvage. Equip-
ment used in disposition ranged widely from three cubic yard
gondolas to fifty-five cubic yard trailers and compactor trucks.
Haul distance was one to five miles except that the haul distance
of one establishment to the municipal incinerator was thirteen miles
Disposal was three incinerators, three dumps, one dump and burn
two sanitary land fill and one unidentified. The disposal agencies
were six city, two self and two contractor owned.
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TRENDS
Generally, no trends in waste/employee or waste/product ratios
were evident.
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SECTION VI
SURVEY RESULTS
J. MEAT PACKING
1. SUB-CODE AND INTERVIEWS
In 1964 there were 1,368 meat packers, defined as firms purchasing
for slaughter more than 1,000 head of cattle or 2,000 head of all
livestock.
The number of meat packing establishments (strictly reporting
units) in 1964 was 2,,831,2 but not all meat packing
establishments conduct slaughter. In Code 2011, there were 177,000
employees and in Code 2013, sausages and other prepared meats, there
were an additional 48,000.
Seven interviews with establishments in 2011 and 2013 were conducted
during this project and eight additional interviews plus earlier
published information were available from earlier studies.
2. WASTE TYPES
The interviews confirmed the almost literal truth of the old state-
ment that slaughter houses utilize every part of the animal except
the squeal. True, slaughter houses 'generate considerable quantities
of waste comprising paunch manure or stomach contents. The only
part of the animal not utilized, and observed in only two inter-
views, was hog hair for hog slaughtering operations. The meat
packing plants not engaged in slaughtering, produced only plant
trash and shipping wastes from packaging lines. Those conducting
slaughtering presumably produce these types of wastes also, but
interviews with such establishments concentrated so much on the
paunch manure and stomach contents problem that not much quantitative
data was obtained. The paunch manure consists of undigested and
partly digested food typically hay and stomach juices obtained
from the four stomachs or paunches of cattle and calves. This
material has a high water content, about 85%, and also a high fat
content. Placed outdoors on a pile and allowed to drain a bit,
it will burn with a greasy persistent flame even when it is
obviously wet.
From hogs the material is better described as stomach contents and
consists largely of undigested corn. All other wastes from packing
plants are either liquids or are customarily flushed with water
and removed via sewers.
3. WASTE QUANTITIES
As implied in the previous section, meat packing establishments that
do not conduct slaughtering operations have only a very small
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amount of waste. The six interviewed establishments in this
category had only 1.5 Kpye average, which is only one-tenth of the
average Kpye for meat packing houses conducting slaughtering
operations.
For the paunch manure some of the interviews and some published
data provided pounds of paunch manure per head for certain types
of animals. The averages of the available figures showed a cattle -
hog ratio of 7.46:1. Two interviews were with packing plants
handling both hogs and cattle for which only the total paunch
manure was known. Using the 7.46:1 ratio on both these establish-
ments produced two additional Ibs./animal ratios. The result
was five ratios for cattle, five for hogs, one only for sheep, and
for calves only a single estimate that paunch manure for calves
was one-third that for cattle. The cattle and hogs Ibs./head
figures were each log-normally distributed with medians of 38
and 5.1 Ibs./head respectively, a ratios of 2.89 and 1.88
(coincidentally, this ratio is also 7.46). If these were characteristics
of the entire population of about 1,400 packing plants in the
nation, the respective averages, Ibs./head, would be 76 and 6.3.
With calves at 22 Ibs./head and sheep at 6, these averages applied
against the total number of head of each of the four types slaughtered
in 1964. This produces 2,613 million pounds per year of paunch
manure and stomach contents of which 71% is contributed by the
cattle.
It is difficult to compute the true confidence limits since involved
is the confidence limit on a summation, the components of which
are log-normally distributed. However, if the confidence limits
of the total are the same as that for cattle, the 68% confidence
interval would be from 1,490 to 2,400 million pounds per year. The
true confidence interval is narrower than this.
Some earlier studies have indicated a productivity for meat packing of
770 head (mixed types) per year per employee. From this ratio, a
corresponding average Kpye may be computed as about 15.
As will be discussed in the disposition section, it is estimated
that only about 50% of the produced paunch manure and stomach contents
enter the solid waste stream of interest. This would be 1,300 million
pounds per year of paunch manure and stomach contents. In addition,
presumably all establishments have the same waste/employee ratio
for the non-paunch manure wastes as do the interviewed establishments
conducting slaughtering, namely 1.5 Kpye. This amounts to another
350 million pounds per year of which the disposition - disposal
study shows 100% is waste for disposal, for a. total of 1,650
million pounds per year from the meat packing industry. With the
assigned growth factor this becomes 2,400 million pounds per year
in 1975. However, this last figure is highly uncertain as will be
discussed under the section on trends.
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DISPOSITION AND DISPOSAL
The disposal of paunch manure and stomach contents from slaughtering
is a major waste problem of the meat packing industry, and the
industry is engaging in considerable activity on a number of fronts.
This activity cannot be adequately covered by the number and itinerary
of interviews available for this study- Among suggestions ranging
from mere ideas to commercial realities, for handling paunch manure
and stomach contents are:
a. Dehydrate and use as animal feed.
b. Dehydrate for soil conditioner,
c. Solvent extraction of the grease for sale and utilization of
the residue for feed or soil amendment.
d. Incineration of the 85% moisture material.
It is clear that with this degree of commercial interest and develop-
ment, predictions about the future of this meat packing industry
waste must be considered highly uncertain.
Nine interviews mentioned the disposition of paunch manure and
stomach contents waste. Two establishments flushed the stomach
contents waste to the city sewer. A group of establishments com-
prising another single interview also flushed the material to a
common sewer, but the sewer fed a common disposal facility which
wet screened the waste and burned the material remaining on the
screen, i.e. the solids, in an open burning pile. The material
passing the screen goes to a settler, the overflow going to the city
sewer and the underflow being lagooned. Judged from the comments
of interviews on the general disposition of paunch manure and
stomach contents, it is likely that the frequency of these materials
discharged to the city sewer system is greater than the simple
interview frequencies would indicate. However, such disposition
removes the material from the scope of the present study.
The high liquid content of the original waste and the ease of
disposition to the sewer or some water course when this is not pro-
hibited by ordinances suggests that it is probably not uncommon
that paunch manure and stomach contents be wet screened leaving
only the material not passing the screen for disposition by the
producer. This was the case with one establishment interviewed and
probably also the case in three other interviews for which it was not
possible to determine whether the paunch manure was screened or not.
In the six cases where there remained solid waste to be disposed of,
either raw paunch manure and stomach contents or screenings there-
from five of the establishments hauled the material themselves
and one used contract disposition.
In two cases, the ultimate disposal was in the city land fill and
in two other cases, to an unidentified city disposal facility.
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It will be recognized that with the paunch manure and stomach
contents waste from the meat packing industry, it has been more
difficult than in any of the other codes studied to distinguish
between solid waste and liquid or liquid-borne wastes. This
difficulty has been accentuated because of the diversity of
disposition and disposal methods which are in use and which bear
on this distinction.
Of the eight cases of disposition of paunch manure and stomach
contents in five it is known whether the material is screened or
not. Of these five, two establishments disposed of all the waste,
two disposed of none of it (as solids) and one handles whatever
fraction of the waste remains on the screen.
Assuming that 50% of the original waste appears as the screening,
and that the small sample of five is representative of the frequencies
of occurrence in population and that the disposition mode is
independent of establishment size, then one half of the total paunch
manure and stomach contents generated will actually appear as a
solid waste to be disposed of.
In six interviews, waste other than paunch manure and stomach
contents is listed, three of these establishments having slaughtering
and three having no slaughtering. For these wastes which are plant
trash, shipping waste and in one case pen waste, disposition is
four self and two contract. In two cases, the material was incinerated
by the producer and in two cases, disposed of in a city sanitary
land fill and a city dump.
5. TRENDS
No quantitative trends in waste/product or waste/employee ratio
were evident from the interviews. However, the ferment of activity
and development in the handling of paunch manure and stomach contents
clearly indicates that some trend is to be expected in a direction
to decrease the quantity of these wastes which must be handled by
a solid waste disposal facility if they are at all successful.
To adequately assess these trends would require a much more com-
prehensive study of the various methods being proposed and a
prediction of their merits and competitive positions.
In the other direction, it is quite likely that water pollution control
measures will gradually prohibit the discharge of paunch manure or
material passing the screens into water courses as is now done where
this is allowed. It is not likely that the discharge of the material
passing the screens into city sewer systems will be prohibited
since there is no pollution involved and the material is of the
type that can be handled by a conventional sewage system plant,
possibly at some additional expense which presumably will be negotiated
Short of flushing the total waste to a water course, this is probably
the most economic disposition that the producer can make and pre-
sumably will be favored unless some of the utilization methods being
proposed should develop profitable values.
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SECTION VI
SURVEY RESULTS
K. CHEMICALS
1. SUB-CODES AND INTERVIEWS
The sub-codes and approximate number of employees in the codes are:
Code Description Employees
281 Industrial organic & inorganic chemicals 240,000
282 Fibers, plastics 148,000
283 Drugs 94,000
284 Cleaning and toilet goods 86,000
285 Paints 62,000
287 Agricultural chemicals 49,000
289 Miscellaneous, including 2895 carbon black 62,000
2,300
There were available six interviews conducted under this project
and seven contributed from prior project work as follows:
Code This Project Prior Projects
281 2 3
282 2 3
284 1
287 1 0
2895 0 1
After studying the interview data it was decided to drop the one
interview in 284 from further consideration because it was a plant
manufacturing both detergents and food items. Code 285, paints, is
not considered here because it constitutes one of the separate
codes being studied under this project.
2. WASTE TYPES
The chemical industry is highly heterogeneous with respect to
wastes and probably cannot satisfactorily be projected even by a
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sample of thirteen. The process wastes are highly specific to each
manufactured product. The major quantity" of process waste in the
interviews was a liquid waste and thus not covered in the present
project. It was no.t uncommon to incinerate combustible liquid
wastes in a pit incinerator. Other disposal methods encountered
for liquid wastes included dumping at sea and injection under-
ground. Four out of the thirteen establishments had no process
waste.
3. WASTE QUANTITIES
There was a distinct difference in Kpye level between the three
Code 281 establishments and the remainder of the establishments
supplying data. The distribution of the waste/employee ratio for
this code was neither normal nor log-normal. The mean was 0.47
Kpye and the estimated standard deviation of the population 0.17.
The corresponding 68% confidence interval for the mean of the
population is +0.14 which means that there is a 68% probability
that the true mean of the population lies in the band 0.47 +_ 0.14.
This mean applied to the total 1965 employment (240,509) in the
code gives 113 million pounds per year as the waste generation. The
estimated 1975 waste total is 211 million pounds per year for this
code.
As with the 281 code, the Kpye's for the other codes combined showed
no trend with number of employees. The distribution was log-normal
with a median of 7.3 Kpye and a a ratio of 2,88. If these are the
characteristics of the entire population of 3,875 such establishments,
the expected average for this population is 12.6 Kpye (the actual
average of the sample was 10.4). Applied against the approximately
200,000 employees in the projected codes (282, 287, 2895), this
gives 2,520 million pounds per year for 1966 and 4,700 million
pounds per year for 1975. These data may be manipulated to provide
the 68% confidence limit on the mean of the logs of the population
of Kpye. When the adjustment is made for the arithmetic average,
the 68% confidence limits for this become 7.6-21, centered of
course on 21.6. This signifies that there is a 68% probability
that the true mean of the population lies in the interval between
7.6 and 21.
4. WASTE QUANTITIES
Over an average for all establishments interviewed, the solid process
waste amounted to about 20% and the plant trash and shipping wastes
about 80%.
5. DISPOSITION AND DISPOSAL
Private disposition is the major mode in t.'ie chemical industry. In
the sample, eleven dispositions were private and only two by
contract. The haul distance was of the order of one to four miles.
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Private disposal is not uncommon, there being in the interview eight
private disposal operations as against five municipal. Of the
private ultimate disposals, four were dump and burn, one dump and
three incineration. Two other establishments had special
incinerators for particular process wastes which constituted special
problems and occurred only in very small amounts. The city disposal
facilities were four sanitary land fills and one dump.
TRENDS
One interview indicated no trend in the waste/product or waste
employee ratio, but three anticipated a reduction in waste/product
ratio. One of these was impelled by state air pollution regulations,
one because of transfer to bulk shipments using less packages, and
one which had a particularly bad process waste problem is considering
changing the product which would reduce the waste.
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SECTION VI
SURVEY RESULTS
L. STOCKYARDS
1. THE INDUSTRY
Stockyards have the S.I.C. classification 4731. In 1963 there were
54 "public terminal markets" assignable to this code. They handled
about 15 million cattle, 2 million calves, 22 million hogs and
6 million sheep; a total of about 22 million "animal units" on the
conventional basis that one cattle equals three calves, four
hogs and ten sheep. 11, 12
The terminal markets are log-normally distributed by size with a
median of 250,000 animal units.
So far as waste production is concerned, the stockyards provide a
holding place for animals in the process of sale or transfer. Most
of the animals are moved out within 24 hours of the time of arrival,
sometimes as little as ten to twelve hours, depending on the
customs at the various markets. Animals to be sold as feeders and
stockers may remain in the yards for longer periods of time, up to
several days.
In addition to the fifty odd terminal markets there were in 1962
1,725 "auction markets". While the business transaction which
occurs differs from terminal markets, the physical handling involving
waste production is quite similar.
The animals pass through the auction market and are held for a
period of time similar to that in terminal markets. In auction
markets, however, it is typical to have auction sales only one or
a relatively few times per week as compared with the continuous
operation of a terminal market. Since the retention time is the
same, the waste production per animal should be the same in auction
markets as terminal markets. In 1962 auction markets handled about
36 million animal units. The markets are log-normally distributed
by animal units handled with a median of about 25,000. However,
auction markets appear to be classified in the standard industrial
classification in Code 0719, Agricultural Services, n.e.c.
The thirteen interviews available comprised some of the largest
terminal markets in the nation and included two small auction markets
2. WASTE TYPES
The waste streams encountered in stockyards are these:
a. Pen waste the material which collects in the pens, composed
of animal manure, plus bedding if it is used, plus hay fed to
the animals which is wasted and drops to the ground.
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b. Truck cleanings material similar to pen waste cleaned from
the trucks delivering the cattle to the yards.
c. Lumber from pen rehabilitation.
d. Plant trash from offices and particularly from hotels and
cafeterias operated by larger stockyards and office wastes
from tenants in the levestock exchange building.
e. Concrete and masonry from repair of pen and alley bottoms.
The pen waste always contains spilled hay, but some yards do not
actually purchase bedding. Depending upon the amount of bedding
and also upon the amount of time that elapses between the time of
production and the time the waste enters the pertinent waste
stream in other words depending on the time in storage piles
the moisture content of the pen waste may vary widely from as high
as 80% to as low as 20%. The bulk density varies accordingly, both
with the dryness and with the amount of bedding. (The term bedding
henceforth will refer to both straw purchased as such and also the
spilled hay which becomes bedding.)
Four rough measures of bulk density, moisture content unknown, one
of them specifically measured on a few trucks by the stockyard
specifically for this project were 450, 890, 1,300 and 1,888
Ibs./cy (pcy).
3. WASTE QUANTITIES
The fraction of concrete and masonry rubble in the total waste is
minute. The one interview in which there was a quantitative measure
gave 0.1% in the total waste.
The quantity of lumber from pen rehabilitation was estimated from
the amount of lumber purchased per year, none of it going into new
construction, but all replacing worn out pens, etc. This waste
stream is also small in relation to the total. The average of seven
interviews gave 1.5% of the total waste.
The amount of hotel and cafeteria waste and plant trash was
available in only three interviews, the average percentage of the
total wastes being 0.8%.
It is clear, therefore, that the great bulk of stockyard waste is
the pen waste including the truck cleanings. Data were available
from four interviews for computing the percentage of truck cleanings
in the pen waste. These percentages were close together and
average 9%.
The typical contribution of the various components to total stock-
yard wastes on the above basis is as follows.
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Pen Waste 97.6%
(including truck cleanings (9.0%)
Hotel and Plant Trash 0.8%
Lumber 1.5%
Concrete and Masonry 0.1%
100.0%
It is seen that so far as quantity projections are concerned, one
need deal only with the pen waste.
In previous Combustion Engineering studies on this subject, the
evidence indicated that "northern" yards used bedding in the pens
while "southern" yards used none. The interviews under the present
project have added to this information and modified it. In the
first place, it was learned that considerable quantities of hay
are spilled in any stockyard and this effectively becomes bedding
so far as the waste composition is measured. Estimates were that
from one-quarter to one-third of the hay fed is spilled and becomes
part of the bedding. Only three quantitative figures were available
on spilled hay and these were from 1.5 to 15% spilled hay in the
pen waste. All of these interviews were from yards that purchased
straw or other material for bedding and the ratio of estimated
spilled hay to total bedding (purchased plus spilled hay) was .17,
.56 and .92. While these figures leave the quantitative situation
unclear, they do clarify the fact that every yard does have bedding
type material in the pen waste whether they purchase bedding
specifically for this purpose or not.
Quantitatively, the percentage of spilled hay in the pen waste is
at least 2%, and this must apply both to "northern" and to "southern"
yards.
An exploration was undertaken to determine the extent of the
differences between "northern" and "southern" yards and the line
of demarkation between them. The percentage of bedding material
in pen waste (including spilled hay estimates) ran from a low of
not less than the above 2% for yards stating they did not buy bed-
ding to as high as 15.3%. An attempt was made to correlate the
per cent bedding in pen waste according to how cold it was (heating
degree days) and how wet it was (average annual precipitation).
The results were not very definitive, but if any results are to be
stated, they would be that the bedding percentage tends to be high,
around 15%, where it is dry and cold and also where it is hot and
wet. It tends to be low where it is hot and dry. No yards were
interviewed in regions that could be called cold and wet. It
seemed technically sound that where the climate is either wet or
cold there will be a tendency to use bedding. Presumably, if
operating practices are such that large quantities of feed hay are
spilled, such yards in these regions will be able to get by without
purchasing bedding.
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The exploration of the boundary between purchasing bedding and not
purchasing bedding was made with the anticipation of dividing the
yards into two groups those with bedding and those without
bedding in order to improve the accuracy of the total pen waste
projection. However, the above figures indicate that the amount
of bedding in pen waste is not likely to be more than 15% under
any circumstances and therefore, considering the other inaccuracies
of the projection, such a separation need not be made.
The previous figures have shown that it is not warranted to consider
the other waste stream separately, so that it is concluded to deal
from this point on with the total stockyard waste including all
components. There remains the relation of this waste to the size
of the operation. In most of the other codes, the waste/employee
ratio is used because employee data are available while production
data are not. However, for stockyards the production data is
indeed more readily available than the employee data since the
U. S. Department of Agriculture has regularly, for many years, kept
and published statistics on the number of animals of each type
handled by each stockyard. Furthermore, in this case it is quite
clear that the total waste production is better related to the
animals passing through the stockyard than it is to the employees
who handle them. However, stockyards differ not only in the total
number of head handled, but also in the numbers of head of each
type, the major types being cattle, calves, hogs and sheep. Required
is some equivalence ratio which will express the waste produced
by one type in ratio to that produced by the same number of head of
another type.
Four different measures for this weighing were considered, in all
cases expressing the other three types in terms of equivalent cattle.
First, it might be considered that the amount of pen waste generated
and thus for our purposes the amount of total stockyard waste
generated would be proportional to the weight of the animal. The
data on weights of animals passing through the stockyards are not
directly available, but there are available data on the average
live weights of livestock slaughtered by type.^
Second, there are available similar equivalences in the "animal
unit" measure used in describing stockyard operations. A third
measure would be the relative content of each animal in feed in the
process of digestion, thus the relative weights of paunch manure
and stomach contents. Using such weights implies that the number
of passages of food through each type animal at the time of its
stay in the yards is approximately equal.
Weighting factors based on these three weight units were as follows,
and the adjusted weighting factors used were developed from these
three.
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Paunch Manure
Slaughtered and Stomach Chosen
Conventional Live Weight Content Weight
Cattle 11 1 1.0
Calves .33 .22 .33* .27
Hogs .25 .23 .093 .19
Sheep .10 .096 .090 .095
* Developed fron conventional measures and, therefore,
not used.
A fourth measure which was considered, particularly prior to the
determination that bedding contents were not major, is the amount
of pen space occupied by each animal on the assumption that bedding
depth for each type is approximately constant and thus the amount
of bedding would be proportional to the pen space. Pen space
recommendations are available from the U. S. Department of
Agriculture and actual space practices were obtained for two of the
stockyards interviewed.j
An adjusted average of these gives the equivalents:
Cattle 1.0
Calves .71
Hogs .30
Sheep .27
With these assignments there were computed waste/product ratios
for each of the eight interviewed yards providing data on total
waste. The units were Ibs./cattle equivalent. Also, as a check,
there were computed waste/product ratios in terms of absolute numbers
of head of all kinds handled, in other words, with the weight of
each type being 1.0. These waste/product ratios of course had a
dispersion. All three were log-normally distributed, and were
almost identical in a ratio, being 2.39. The Ibs./cattle
equivalent, weight basis, data were then studied for correlation
with cattle equivalents handled and showed no trend with size.
The study of this code was exceptional in that since there are
only fifty-four stockyards (1963) and the interviews have covered
eight from among the larger of these. It actually happens that
already contained in the interview sample is more than half of the
total animals handled by all stockyards, specifically having 58%
of the cattle, 34% of the calves, 61% of the hogs, 44% of the sheep
and 57% of all head. This means that the projection need be only
for the remaining forty-six stockyards handling 43% of the total.
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If the non-interviewed forty-six stockyards have the statistical
characteristics described above for the interviewed yards, the
average Ibs./cattle equivalent would be 34 and the 68% confidence
interval on this average would be from 24 to 48.
The cattle handled by the forty-six yards in 1963 comes to 8.66
million cattle equivalent on the 1.0, 0.27, 0.19, 0.095 weighting
basis. At the average waste/product ratio this gives 295 million
pounds per year for the forty-six and the actual total of the eight
interviewed yards is 414 million pounds per year. Thus, the total
projected waste currently is 709 million pounds per year.
If it be assumed that reinterview of the eight stockyards would
produce the same total waste quantities, then the dispersion in
this part of the total projection is zero and the dispersion of the
Ibs./cattle equivalent applies only to the projected portion. On
that basis, the 68% confidence level for the 709 million pounds per
year would be from 623 to 830 million pounds per year.
In addition, the 1,725 auction markets handle approximately 36
million animal units annually (1962). As previously mentioned, the
animal unit is computed on a weighting basis of 1.0, 0.33, 0.25,
0.10 which does not differ greatly considering the degree of
approximation from the cattle equivalent weighting ratios used for
pen waste. If the 34 Ibs./cattle equivalent applies to this
production, and there is no evidence that it should be any different,
the total auction market to waste would be 1,210 million pounds per
year with a 68% confidence interval from 860 to 1,710. The total
livestock market waste would be 1,919 million pounds per year with
a 68% confidence interval from 1,480 to 2,540. That these are not
the waste figures with which this study is concerned is explained
in the next section.
4. DISPOSITION AND DISPOSAL
The disposition of the pen waste and the non-pen waste will be con-
sidered separately, the pen waste, of course, being by far the
major portion of the total. The modes of disposition of pen waste
as determined from the interviews may conveniently be divided into
three categories.
Some waste is sold for a nominal price or given away directly for
use on farm land as fertilizer. Some stockyards allow individual
farmers to take fertilizer from the disposal site or a storage
site directly. Two stockyards have been highly successful in
encouraging a commercialization of this operation in which the pen
waste, after curing in a pile after about six months, is hauled by
merchant operators to farmers in the area. The stockyard provides
a crane and an operator for loading and charges the merchant $1 per
load. The operation started through off-season use of the gravel
trucks, but more recently several operators have developed large
manure trucks incorporating spreaders with which they spread the
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material directly on the farmer's field. The average distance
transported by the merchant haulers is about twenty-five miles.
The charge made to the farmers by the merchanized operators is $2
per ton for the first twenty miles plus 10c a ton a mile there-
after with the scale dropping to 5C per ton a mile beyond a certain
distance. The maximum distance hauled is as high as sixty miles.
The gravel truck operators who simply dump the material in the field
for later spreading charge $2 per ton for distances up to thirty
miles.
The stockyards engaging in this operation have been very success-
fully disposing of their pen waste to a useful purpose and are to
be commended in the solution. There are some restrictions on the
universal application of this solution. It is necessary that the
stockyard be located in an area given to the type of farming which
can use the fertilizer. It happens that the two stockyards in question
are in the middle of a corn and wheat raising region where such
application of fertilizer is practical. The stockyards with the
assistance of the State Agricultural Experiment Station have promoted
this use of the fertilizer by demonstrating the effectiveness in
increasing yields, showing that weed seeds are not viable in the
product, etc., and one stockyard itself engages in a continuing
publicity campaign in farmer's magazines and newspapers stressing
the practice. If a stockyard, however, is located say in a
dairying' region where it is not practical to utilize the fertilizer
on pastures, then this solution would not be available to them.
With the major stockyard engaging in this practice there still remain
a few difficulties. It is necessary to be scrupulous in avoiding
extraneous trash in the pen waste. Thus, it is necessary to
constantly be alert to keep wire, concrete, can, etc. out of the
pen waste. The operation has been successful for ten years or more
because of unusually favorable weather conditions which allow the
operators to get into the pile and spread in the fields. If there
should be a prolonged wet spell during the winter months, it would
not be possible to move the pen waste in that season. Finally, it
must be considered unfortunate, against such an exemplary operation,
that the general public in the city in which the yard is located
still find objection to this disposition method. The objection
comes because of the practice of storing the pen waste in piles for
curing and composting for a six month period operating from one
pile while waste is being accumulated on another. This makes the
waste much more easily handled by the operators and the curing process
is responsible for the killing of the weed seeds. The raw waste
loses about 30% of its weight in the process. This in itself is
not of importance, but the community complains about the storage
piles which happen to be not far from a new expressway entrance to
the city.
A second mode of disposition is to sell or give away the waste for
processing into fertilizer. This is typically done by an organization
separate from the stockyard although it may be owned or controlled by
the stockyard. One yard transfers the waste to an outside processor
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who composts it. The more common practice however, is dehydration,
which incidentally stockyard operators are likely to term
"incineration". The processing establishment may be on the stock-
yard ground or the yard may haul pen waste to the processing plant
at another location. On the average, it takes four tons of pen
waste to produce one ton of processed fertilizer. The bagged
fertilizer may be sold under the yard's own brand or under other
proprietary brand names. If the waste is sold for this purpose,
the return is only nominal.
For processing into fertilizer, it is desired to have as little
bedding, i.e. straw and hay, as possible in the raw material. There-
fore, where there is a heavy use of straw or heavy spillage of hay
resulting in considerable bedding components processing to fertilizer
by dehydration is contra-indicated. Yards, therefore, attempt to
select for dehydration that portion of the pen waste containing the
least bedding, and to dispose otherwise of the heavy bedding
material. Yards disposing by dehydration make efforts to keep the
hay and bedding out of the waste for this purpose. Where this is
unavoidable due to practical or conventional considerations, it is
indicated to compost the waste rather than to dehydrate it as the
means for processing into fertilizer.
The third disposition mode is to haul the pen waste to a dump
sometimes located at the yards,in other cases some distance away.
In this study it is considered that this third mode of disposition
is the only one by which the pen waste enters the waste stream of
interest to this study, since the other two modes now successfully
dispose of it by utilization and without a great deal of cost to the
producers. One interviewed establishment in this third disposition
mode provides a logical problem for the researcher since he could
give the material away to farmers, who presumably would be willing
to take all of it, but the responsible authority at the yard is of
the belief that the material has value and should be paid for.
Since he has adequate storage area to handle it, the material is now
being stored at the yards. This establishment incidentally formerly
operated a dehydration plant but found it, in his particular
circumstance, unprofitable and therefore, put it in stand-by.
In eleven of the interviews, it was possible to establish what per-
centage of the pen waste went to each of the three modes of
disposition. Table VII shows these percentages and gives the average
of all, each being considered of equal weight. If this sample is
representative of all yards and if the mode of disposition is not
a function of animals handled yearly, then the averages given in
the last column of Table would be the percentages of total pen
waste going to the three modes. This would be 30% to processing for
fertilizer, 30% given away to farmers, and 40% remaining a problem.
This summation counts the establishment which could give away its
waste, but is now storing it as in the third disposition mode,
i.e. constituting a problem.
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TABLE VII
DISPOSITION MODES
PEN WASTE
Mode
(Eastablishment)
Sell or give away
for processing
into fertilizer
% of Establishment's Total Pen Waste
A 1 C ID E F_ G_ H !_ J_ K
100 96.5 40 100
Average of
1L. %
30
Give away to
farmers for
fertilizer
100
3.5 6.3 100 100
25
30
To dump or storage;
in general, con-
stitutes a disposal
problem now
100
100
93.7
60
75
40
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These numbers might be applied to the total waste in the manner
used for other codes in this study, but in this case as for
total quantities it is possible to improve upon the confidence
interval by taking advantage of the fact that we already have
information on the disposition modes for more than half of the
waste produced. There are available nine interviews for which
the quantities going to the three modes are known and two inter-
views providing percentages on dispositions from two other yards
for which the total quantities are known. It is possible to project
the total waste of these two yards by taking their cattle equivalents
handled and multiplying by the most probable value of the waste/
product ratio, namely the median 26.2 Ibs./cattle equivalent.
This produces dispositions for the eleven yards as follows:
Million Ibs./yr. Percent
Processed 114 25.9
Farmers 138 31.4
Problem 187 42.7
TOTAL 100%
The total waste accounted for here for which the disposition mode
is known is about 62% of the total waste estimated for all yards.
The incidence figures from Table VTI thus are to be applied only to
the residual of 269 million pounds per year. When this is done,
and the two sets of figures combined, the projection shows that of
the total pen waste of the fifty-four terminal stockyards amounting
to 709 million pounds per year, 195 million pounds per year or 27.5%
is sold or given away for processing into fertilizer, 219 million
pounds per year or 30.8% is sold or given away to farmers for
direct application as fertilizer, and 296 million pounds per year
or 41.7% becomes a waste, subject to ultimate disposal and is
therefore the waste of interest to the present study. The 68%
confidence interval on this 296 million pounds per year is from
265 to 340.
The disposition study and computations, having been obtained almost
solely from terminal stockyards, apply only to the terminal stock-
yard waste. It is quite possible that the disposition modes for
the auction yards, since they in general are only one-tenth the
size of the terminal yards, might be quite different. There is
no way of determining this without an interview campaign among the
auction yards. However, if the results should be that the disposition
modes of the auction yards are the same as for the sample terminal
yards (TableVII) then of total waste of the terminal yards and the
auction yards amounting to 1,919 million pounds per year, 29.1% or
558 million pounds per year would be sold or given away for processing
in fertilizer, 30.3% or 582 million pounds per year would be sold
or given away to farmers for direct application as fertilizer, and
40.6% or 779 million pounds per year would become the waste subject
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to ultimate disposal and thus, of interest to the present study.
The 68% confidence interval of this 779 million pounds per year
could be computed as before, but in view of the large uncertainty
of the application of the terminal yard disposition mode to the
auction yards, this seems unwarranted.
Incidental to the above in two establishments the waste from the
hog house was flushed to the sewer and thus, becomes a waterborne
outside the province of this study.
The non-pen waste, comprising an average of only 2%, of the total
waste, was disposed of in the six pertinent interviews once in a
self owned incinerator, once in a self owned tepee burner, three
cases of open burning self owned, one self owned dump and one
contract hauling to city sanitary land fill.
5. TRENDS
Evident from the interviews was a general trend to seek a greater
degree of utilization of the pen waste, to avoid pollution of water
courses or from open burning, and to solve problems arising from
running out of dumping space. (The anti-pollution sentiments were,
however, not universal in the interviews.) This trend will, of
course, reduce the quantity of waste for ultimate disposal and
presumably will ameliorate the problems connected with ultimate
disposal. However, it is not capable of quantification.
In particular, the trend for total waste from stockyards contains
complications beyond the capabilities of the present study. The
total number of cattle handled will presumably increase during the
next ten years along with the increase of population in a way
which probably has been quantified. However, this quantification
is not important to the present study because of the large
uncertainty in other factors.
Some of the interviews revealed that the decentralized auction
markets were taking an increasing share of the animals handled. In
part, this comes about through the introduction of truck trans-
portation of livestock, replacing the former high concentration of
rail handling. The terminal markets were set up primarily as con-
centration points for rail shipments of cattle and the historical
figures for almost any stockyard will show the extreme deterioration
of the rail hauling aspect and its replacement by truck deliveries.
If truck delivery is the practice, then it becomes efficient from
the standpoint of handling, to decentralize the market into smaller
markets. But smaller markets cannot support the merchandizing
structure of the large terminal markets and thus, tend to become
auction markets.
There are numerous advantages and disadvantages of such a trend
judged from the overall standpoint of merchandizing, price com-
putation, etc., but this study is concerned only with the fact of
its existence. Measured by the purchases of livestock by packers
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(and packers purchase about 80% of all of the total head passing
through the terminal stockyards), the terminal markets share of
total packers purchases has fallen between 1960 and 1964 from 45.8%
to 36.5% in cattle, 25.4% to 18.8% in calves, from 30.3% to 23.8%
in hogs and from 35.4% to 28.6% in sheep. This suggests that the
terminal markets will not share proportionally in the growth of the
livestock handling industry in the next ten years, unless some
radical reversal occurs.
The share lost by the terminal stockyards has been taken up in
part by the auction yards and in part by direct sales and country
dealers. If auction markets do indeed have the same waste/product
ratio as terminal markets, then the pen waste generation "lost"
by the terminal markets will be in part replaced by an increase in
the auction markets. But whether the direct sales and country
dealer sales is to increase in the future at the expense of the
auction markets is uncertain and it seems unwarranted to venture a
prediction without a deeper study. Furthermore, as previously
mentioned, the interviews do not allow a description of the modes
of disposition for the auction markets, and since this is essential
to a projection of the solid waste of interest to this study, the
subject is still further removed for quantification.
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SECTION VI
SURVEY RESULTS
M. PAINTS
1. SUB-CODES AND INTERVIEWS
Paints and allied products, Code 285, is divided into paints,
varnishes, lacquers and enamels, Code 2851, and putty, calking
compounds, etc., Code 2852. The bulk of the employees, of course,
is in 2851 and all eight available interviews were in that code.
The projection, however, is on the entire Code 285, having
approximately 62,000 employees.
2. WASTE TYPES
Three of the eight establishments interviewed had mentioned solvents
as a waste, but these being liquids are not included in the study.
The interviewed establishments had plant trash and shipping waste
and some of them separately listed process waste consisting of
contaminated pigment bags, tars and semi-solids. Where separately
listed, these process wastes comprised about 30% of the total.
3. WASTE QUANTITIES
The eight Kpye's were log-normally distributed with a median of 4.5
and a a ratio of 2.04. The trend with number of employees is not
significant at the 5% level. If these are the characteristics of
the entire population of 1,725 establishments, the average Kpye
would be 5.25 and the 68% confidence interval from 3.6 to 7.7.
Applied against the total number of employees, this gives 324
million pounds per year, and with a growth factor of 1.22, 394
million pounds per year in 1975.
4. DISPOSITION AND DISPOSAL
Disposition is by truck or Dumpster, five waste streams being handled
by self and seven by contract. The ultimate disposal type is two
dump, two sanitary land fill, two open burning and two incinerators.
The ownership of the ultimate disposal facility is three self, two
contractor owned and two city owned.
5. TRENDS
No trends affecting the waste picture were evident.
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SECTION VI
SURVEY RESULTS
N. ELECTRICAL MACHINERY
1. SUB-CODES AND INTERVIEWS
The interviewed sub-codes were as follows:
Code Description Employees En tervlc:ws
361 Electric transmission and distri- 5
bution equipment
362 Industrial apparatus 4
363 Household appliances 1
365 Radio and TV 2
366 Communication equipment 1
367 Electronic components 3
369 Miscellaneous 1
1,327,581
The remaining uninterviewed three-digit code which was non-projected
is Code 364, Lighting and Wiring Equipment, with 138,186 employees.
Of the total of eighteen interviews, thirteen were obtained in the
present project and the remaining five came from previous work.
2. WASTE TYPES
In addition to plant trash and shipping waste, the latter sometimes
including styrofoam, the process wastes included metal scrap, rubber,
plastic and a small amount of wire scrap. The quantity of wire
scrap coming from radio and TV manufacture was decreasing due to the
increasing use of printed circuits.
3. WASTE QUANTITIES
The eighteen Kpye's showed no trend with employee size or with
four-digit sub-code. The Kpye's for scrap and waste were log-normally
distributed within the tolerance set for that characteristic, but
the deviations therefrom were such that a slightly better fit was
obtained by an arithmetic normal distribution. Computed by both
methods, the mpy for the arithmetic distribution was about 12%
less than that for the log normal. Because of the weight of
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evidence of the other codes for the log normality of Kpye's, it
was judged that the distribution of the population in Code 36 would
also be log normal despite the fact that for the particular sample
the arithmetic normal was ta slightly better fit. On this basis,
the median was 1.80 Kpye and the a ratio 2.49. If this is the
characteristic of the entire population of 9,500 establishments, the
average Kpye would be 2.75 and the 68% confidence interval thereon
from 2.2 to 3.5. Applied against the number of employees in the
projected code, this gives 3,651 mpy scrap and waste in 1965.
The disposition - disposal analysis in Section V indicates that
24.4% of the scrap and waste is utilized, thus leaving 2,760 mpy as
waste for disposal. A 1.8 growth factor gives 4,960 mpy waste for
disposal for 1975.
4. TRENDS
No trends in production practices over the next ten years were
anticipated which would alter the waste/product ratio.
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SECTION VI
SURVEY RESULTS
0. RUBBER
SUB-CODES AND INTERVIEWS
Code 30 is titled "Rubber and Miscellaneous Plastics Products".
The sub-codes, together with the number of employees therein are:
Code Description Employees
301 Tires and tubes 86,000
302 Footwear 29,000
303 Reclaimed rubber 2,000
306 Fabricated rubber 131,000
products (n.e.c.)
307 Miscellaneous plastics 170,000
products
Despite its inclusion in Code 30, industry 307 is not strictly a
rubber handling industry and, therefore, was excluded from the
survey.
Four interviews were conducted in 306 and two in 301. Two Kpye
figures were obtained from studies conducted in 1949 by
R. H. Stellwaegen. In addition, four interviews were made available
from a prior Combustion Engineering project.
WASTE TYPES
In general, the rubber establishments had plant trash and some
shipping waste. Most also had process waste. The process wastes
are of two types: (1) rubber and rubber trimmings, etc. and
(2) solvents and pigments.
The rubber waste is difficult to incinerate partly because of its
high BTU content, and partly because of the high temperature necessary
to avoid smoke. Two interviewed establishments had abandoned
incinerators because of poor air pollution performance and as
indicated in the disposal section, only one establishment is
operating an incinerator for disposal and that on only 3% of its
waste for the purpose of reclaiming the metal in the waste product.
Apparently, if rubber is mixed with general municipal rubbish for
incineration, satisfactory performance can be obtained. Thus, the
one plant for which incineration was the ultimate disposal for a
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major portion of its process waste, accomplished this incineration
by mixing it with other municipal waste.
In 1949, a study was made under the auspices of Akron, Ohio Chamber
of Commerce by Robert H. Stellwaegen. This comprised an analysis
of the problem of disposal of Akron municipal wastes, together
with the wastes of the five major rubber companies located there.
The characteristics of the rubber wastes cited below are those from
that report.
The average proximate composition of rubber wastes generated is 75% C,
10.5% H, 2.5% S, and 12% ash, which computes to a heating value of
17,570 BTU/lb. of rubber. Scrap rubber from tire manufacture will
comprise 60% treads and 40% carcasses, giving overall 68% rubber and
32% fabric with a heating value of 13,480 BTU/lb. of scrap. Beads
may be incinerated separately to recover the contained metal. They
comprise about 15% metal and 85% rubber and fabric in the proportions
described above. If precleaned, the bead material is 98% metal.
The liquid type waste, solvents, oils, pigments, etc. comprise
29% oil and grease at 18,500 BTU/lb., 47% solvents at 18,000 BTU/lb.,
and 25% cements, latex, etc. at 17,600 BTU/lb. Overall, the process
type waste from these five major plants was made up of 46% rubber
scrap, 45% beads, and 9% solvents, pigments, etc.
The report data indicates that of the total waste produced by the
rubber establishments, 48% was process waste and 52% was non-process
waste, i.e. plant trash and shipping waste.
3. WASTE QUANTITIES
For the interviews from this project there was no trend of Kpye with
number of employees, and the Kpye level was higher but not
significantly higher than the level from prior projects. The values
for Code 306 were not significantly different from the other points.
The eight Kpye points were log-normally distributed with a median
of 3.9 Kpye and a a ratio of 4.62. If this distribution were
characteristic of the universe of 1,368 rubber plants, the average
waste/employee ratio for these 1,368 plants would be 11.9 Kpye which
corresponds to a waste generation of about 2,900 million pounds per
year for the 247,000 employees represented. The confidence interval
on the mean is 6.7 to 21.3.
An interesting analysis was made possible by the availability of
waste/employee ratios for three identical plants in 1949 through the
Stellwaegen report and in 1964 through previous work done by
Combustion Engineering. It was found that despite considerable
changes in employment in these three plants the waste/employee ratios
changed very little. If this constancy of the waste/employee ratio
over the fifteen year period is characteristic of the rubber
industry as a whole, then it may be inferred that the waste/product
ratio in the same period has decreased markedly; for in the period
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1950 to 1963, employment in the tires and tubes segment of the
industry has declined by about 13% while production has increased
by 68%. With a constant waste/employee ratio, this requires that
the waste/product ratio has declined by some 50% in the period.
These statements are only roughly quantitative and are drawn only
from the tires and tube segment of the industry. However, there
appears to be enough information to suggest considerable caution
in projecting 1975 waste via the waste/product ratio which is
proposed for this study. Since three of these individual establish-
ments showed a constancy over the period in the waste/employee
ratio, it was assumed that the other two plants also had this
constancy and that for that reason the 1949 Stellwaegen report data
could be used in the present analysis. In the absence of further
substantiating data, the projected waste for disposal in 1975 was
obtained by multiplying by the predicted production gain for the
whole code over the time period.
4. DISPOSITION AND DISPOSAL
In the eleven available interviews the disposition for seven was by
contract and for four by self. Within this code there does not
appear to be any trend to one or the other type of disposition,
either with number of employees or with Kpy (thousand pounds per
year). Only a few interviews of the total provided information on
the types of disposition equipment, but in those cases, this was
trucks or container loading truck. Haul distances in the interview
were short, averaging about three miles with a maximum of seven one
way.
Out of sixteen disposal situations in the eleven interviews, only
one waste stream constituting a major portion of an establishment's
waste was incinerated. Oddly enough, this incineration was in the
municipal incinerator, while at the same time the pallets, wood
boxes and shipping waste were hauled to a dump. Another establish-
ment used incineration, but only on 17% of its total waste comprising
paper, lumber, etc. A third establishment incinerated 3% of its
waste specifically to reclaim the metal in the fabricated items.
All the rest of the disposal situations were to dumps or sanitary
land fills about equally divided. One establishment dumped a small
portion of its waste, consisting of solvents and pigments, into an
abandoned mine.
The ownership of the ultimate disposal facilities were three self
(i.e. private), seven municipal, one not self, n.e.c., and one
contractor owned.
5. TRENDS
The interviews did not produce any direct statements concerning
trends in the industry which might affect waste generation and
disposal. However, as described in a previous section, the constancy
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of the waste/employee ratios for three plants requires that the
waste/product ratio has decreased markedly over the past fifteen
years. A continued decrease in the next ten years is, therefore,
possible.
Rubber waste has a high BTU content and except at a very high
temperature produces a smoky flame. This produces problems in
incineration. Of this problem waste, the generation per employee
is almost ten times what the employee generates in municipal refuse
as a private citizen. In a typical city the number of rubber employees
is probably quite small and the problem therefore is not great. In
one city, Akron, there is a notable concentration of rubber
establishments, presumably a corresponding high percentage of total
employment generating rubber process waste, and a consequent high
proportion of rubber process waste in the overall community, wastes.
Indeed, in the Stellwaegen report the wastes from the five major
rubber establishments were estimated at 38% of the total community
waste.
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SECTION VI
SURVEY RESULTS
P. GLASS
1. SUB-CODES AND INTERVIEWS
The interviews covered the sub-codes 321, Flat Glass - 23,000
employees and 322, Glass and Glassware Pressed or Blown - 95,000
employees. These sub-codes comprise the manufacturers of glass
products from glass produced in the same establishment. The
interviews on this project included five establishments in 322 and
one in 321, being a plate glass establishment. Also available was
an interview from a prior project in 321 in the window glass
category.
2. WASTE TYPES
For both sub-codes there can be distinguished two types of waste:
Type 1 is combustible and comprises plant trash, shipping waste,
sawdust and paper cardboard. Type 2 is non-combustible and
comprises process waste, glass cullet, defective batch material,
and plaster and abrasives from the polishing of glass, and defective
product. The Type 2 wastes will contain only a small percentage
of combustible material. If the content of grinding and polishing
materials is high, it may contain considerable moisture.
3. WASTE QUANTITIES
Within each sub-code there was no trend of waste/employee ratios
with number of employees, but there was a distinct difference in
Kpye level between the two codes.
In the 321 code the one interview from this project happened to be
of a plate glass manufacturer and such establishments have appreciable
quantities of Type 2 waste arising from the grinding and polishing
operations. The second interview obtained from a previous project
was a window glass manufacturer, presumably not having these grinding
and polishing wastes. However, the Type 2 waste quantity in that
interview had not been obtained since it was not within the purpose
of the previous project. In order to provide data useful for the
present project, there was computed the Kpye for the plate glass
plant, Type 2 wastes excluding the grinding and polishing waste,
and this Kpye was assigned as the Type 2 waste of the window glass
plant, of which it then comprised of the order of 50% of the total
waste. With this adjustment, the two waste/employee ratios had an
arithmetic mean of 111 Kpye. The actual numbers were 92 for the
window glass plant adjusted and 131 for the plate glass plant. To
be consistent with the remainder of the data here presented, the
estimated arithmetic standard deviation of the population based on
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this sample of two is 28 Kpye and the 68% confidence limit of the
mean is 39; thus it may be anticipated that 68% of the population of
such plants will have a Kpye in the band 111 +_ 39. This assumes
that establishments in this code are equally distributed between
plate glass establishments and flat glass establishments, an
assumption which is probably not correct, but not resolvable with
the information available at this state of the project. The
percentage of Type 1 waste in the total for the 321 sample percentage
was 8% for the plate glass plant and 50% for the window glass plant.
For the 321 code, the percentage of Type 1 waste in the total waste
for five samples was 42%, 12% and three cases with a very low
percentage. From these data an estimating figure for the entire
glass industry projected would be of the order of 10 to 20% Type 1
waste.
For the 322 code the distribution of Kpye's was neither normal nor
log-normal and actually was even more skewed than a log-normal
curve. The arithmetic mean of the five values is 6.3 Kpye. The
estimated arithmetic standard deviation of the population is 6.0
and the 68% confidence interval of the above mean is 6.0+3.2.
This means that 68% of the population values are estimated to lie
in the band between 3.1 and 9.3 Kpye.
Applied to the total employees in each code separately, these yield
2,600 million pounds per year for Code 321 and 600 million pounds
per year for 322. The disposition - disposal study indicates that
about 16% of this waste finds other disposition so that the waste
for disposal is 2,680 million pounds per year currently and 3,936
million pounds per year in 1975.
4. DISPOSITION AND DISPOSAL
One establishment was putting its process waste in the sewer, but
intended to discontinue the practice shortly. The remaining
dispositions for the Type 2 waste were three self and two contract,
and for the Type 1 waste, three self, one contract and one sold.
The hauling was performed with Dumpsters and dump trucks.
The disposal means for Type 1 waste comprised three private disposal
facilities at the establishments, two tepee burners and one open
burning. For Type 2 waste, the disposal consisted of two city
sanitary land fills, one private dump, one merchant dump and one
unspecified dump.
5. TRENDS
S everal establishments indicated that they were in rapid growth.
There is no indication that the waste/product ratio will change in
the future.
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A recent development in plate glass manufacture is the float process
whereby the molten glass is cast on a liquid surface instead of
on a solid table. This will not change the waste/product ratio, but
it will greatly decrease the number of employees and thus, if the
float process takes over in plate glass manufacture, the waste/
employee ratio in that segment of the industry will increase and
will no longer be the same as that in the window glass segment.
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SECTION VI
SURVEY RESULTS
Q. ASPHALT ROOFING
1. SUB-CODES AND INTERVIEWS
Prior information was available indicating that in asphalt roofing
manufacturing, Code 2952, the waste/employee ratio was very high
and the disposal presented difficulties. The code has 14,300
employees and eight interviews were conducted.
2. WASTE TYPES
The wastes consist of scrap roofing, machine break, trimmings,
damaged roofing rolls, felt and roofing granules. Because of its
physical form (in sheets) and weight, the scrap material is
difficult to handle. In addition, in an incinerator it burns with
a hot, smoky flame and has a very high ash content because of the
granules. Open burning produces dense smoke.
3. WASTE QUANTITIES
The eight Kpye's showed no trend with size and were log-normally
distributed with a median of 55 Kpye and a a ratio of 3.24. If
these are characteristics of the entire population of 231 establish-
ments, the average Kpye would be 82.5, and the 68% confidence
interval would range from 51 to 133. Applied against the total
number of employees, this gives 1,180 million pounds per year.
But the disposition - disposal study shows a small percentage used
for fuel and the waste for disposal becomes 1,148 million pounds
per year, and with a growth factor of 1.34, 1,538 million pounds per
year in 1975.
4. DISPOSITION AND DISPOSAL
Disposition was by truck and dump truck four self, three contract
and one unknown. Two establishments hauled about five miles. One
establishment was able to sell or give away a very small portion of
the waste for use in paving driveways, parking lots, etc. Ultimate
disposal was five dumps, two sanitary land fills and one unknown;
ownership of the ultimate disposal facility being five private,
one city and two unknown.
5. TRENDS
The disposal of these wastes is a real problem to the industry and
indications were that an incinerator which would handle them would
be welcome. One roofing manufacturer at one time had an incinerator
and used the recovered heat in the asphalt stills. There was no
evidence of any trends in waste/product ratio.
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SECTION VI
SURVEY RESULTS
R. MILL WORK
1. SUB-CODES AND INTERVIEWS
Mill work comprises Code 2431 with about 66,000 employees. The raw
material for the industry is typically finished lumber manufactured
by a saw mill and already seasoned. Nine interviews were available,
all in Code 2431, with some subsidiary production in 2511 (cabinets)
and 2433 (prefabricated houses) and an interview available from an
earlier project in Code 2433 indicated that the Kpye is of the
same order as the Kpye for mill work and accordingly, no bias is
expected from the one combination interview.
2. WASTE TYPES
The wastes in addition to plant and office trash comprise dry wood
in the form of sawdust, shavings and wood scraps. Two establish-
ments, manufacturing windows, also had shipping wastes comprising
the cartons and boxes in which the glass is received.
3. WASTE QUANTITIES
As will be shown in the disposition section, a considerable fraction
of mill work waste is sold. A similar statement can be made about
saw mill waste and wooden container waste and in those cases, the
quantity sold is subtracted from the total waste before computing
the Kpye's. This will not be done with mill work wastes for the
following reason. The fraction of saw mill waste which is chips is
relatively constant among establishments and it is almost universal
to sell 100% of these chips. Thus, the waste stream of interest is
that excluding chips and the Kpye excluding chips will project this
stream of interest. However, with mill work wastes, although about
half of the establishments sell some of their wastes, the fraction
sold is quite variable, ranging in the actual interviews from 29
to 91% of the total wastes. This means that even if the Kpye's for
total waste were identical for each establishment interviewed, the
Kpye's for the non-sold waste would have a dispersion. In other
words, excluding a variable component increases the dispersion of
the resulting Kpye's. It is desirable to achieve the maximum
constancy of the Kpye's unaffected by the random practices of
disposition. Only if the disposition practices are not random, but
are constant, or are relatively constant and simply described then
it may be preferable to deal with some residual portion of the
waste.
On this basis, the nine Kpye's show no trend with employee size
are log-normally distributed, and have a median of 10.3 and a a'ratio
of 2.62. If this is characteristic of the population of 3,430
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reporting units (approximately equal to establishments), the
average Kpye would be 16.3 and the 58% confidence interval from 11
to 23.
Applied to the total employees in 2431, this gives 1,072 million
pounds per year for the total waste. As will be shown in the
disposition section, the waste disposed of without cost to the
producer is estimated at about 47% and thus, only 53% of the above
total enters into the waste stream of interest. This is 570 million
pounds per year at present and with a growth factor of 1.56, projects
to 886 million pounds per year in 1975.
DISPOSITION AND DISPOSAL
Six of the nine interviewed establishments sold some of the wastes
and in five of these, it was the sawdust that was sold. One
establishment shipped it 800 miles. The average percentage of their
wastes sold by these six is 58%. Two establishments out of nine
used some waste for fuel, in both cases scrap wood and plant trash.
The average of their wastes so used was 16%.
Two establishments gave away shavings, wood blocks and some sawdust.
The average percentage of their wastes thus given away was 20%.
If each establishment be given an equal'weight, which amounts to
assuming that this is a random sample of all establishments and
that there is no trend of disposition method with size, these data
would indicate that 39% of total mill work wastes are sold, about 4%
are used for fuel and another 4% are given away. Thus, a total of
47% is disposed of without cost to the producer and, therefore,
does not enter into the industrial waste stream of interest to this
proj ect.
Of the remaining eleven disposition situations, five were self,
three contractor and three city pickup.
The disposition equipment was small and large trucks and dump trucks,
one haul distance being as much as ten miles.
The method of ultimate disposal was five dump, one open burning,
one sanitary land fill, two incineration and two unknown. The ultimate
disposal facility was owned by two self, six city and three not
self.
5. TRENDS
No trends in waste/product or waste/employee ratio were evident.
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SECTION VI
SURVEY RESULTS
S. TANNING
1. THE INDUSTRY
Leather tanning and finishing constitutes one sub-code 3111 in .
Code 31, "Leather and Leather Products". It has 516 establishments
and 30,800 employees. The six interviews from this project and one
available from a prior project included one establishment engaged
in curing hides which is strictly in Code 2011, "Meat Packing".
However, this was an independent operation not involving meat
packing as such and since the Kpye was median to the Code 27 inter-
views, it was included as a leather tanning industry. The pattern
of the tanning industry is that the animal goes to the packer, who
produces the hide. About 80% of the production of hides goes to a
hide dealer who brine cures and rough fleshes them, commonly selling
this waste to a rendering plant. The hide, still bearing the hair,
'goes to the tannery where it is tanned. About 20% of the production
by-passes the hide dealer and goes directly from packer to tannery.
2. WASTE TYPES
Waste types included plant trash, sawdust and shavings, wet trim-
mings, hair and fleshings and dry trimmings, hair and fleshings.
The dry trimmings, hair and fleshings were sold in all interviews,
and are not contained in the Kpye figures given. In one establish-
ment the wet trimmings, hair and fleshings comprised 13% of the total
waste and the dry trimmings, hair and fleshings comprise about
one-tenth this amount.
3. WASTE QUANTITIES
The distribution of Kpye's, eliminating the small amount used as
fuel in two interviews, is log-normal with a median of 5.1 and a
a ratio taken to correspond to the population of 5.7. This gives a
68% confidence interval for the deviation ratio of 2.17+1. if
this is the characteristic of the entire population of 516
establishments, the average Kpye would be 19.4 and the 68% interval
from 9.0 to 42 Kpye. Applied against the 30,800 employees in the
four-digit code, this yields 598 million pounds per year. At a
physical growth ratio of 1.12, the projected waste for 1975 is
670 million pounds per year.
4. DISPOSITION AND DISPOSAL
Disposition is by truck, six private, five contract. The two cases
of use of a small percentage for fuel are not included. The ultimate
disposal type is ten dump and one incinerator and the ultimate
disposal facility ownership is three private, seven city and one
merchant.
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5. TRENDS
There was no indication of any trends in waste/employee or
waste/product ratio.
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SECTION VI
SURVEY RESULTS
T. PRINTING AND PUBLISHING
1. SUB-CODES AND INTERVIEWS
Code 27, "Printing and Publishing", is complicated by the fact
that about half of the total employees occur in the three sub-codes
which comprise both printing and publishing, namely 2711, 2721 and
2731. In these sub-codes it is not possible from data available
to the project to determine what fraction of the employees are in
the publishing phase (i.e. the intangible operation) and what
percentage in the printing phase which would produce the waste.
In newspaper printing and publishing, the printing employees are
well in the minority. Accordingly, it may be expected that the Kpye
for these three codes would be substantially less than the Kpye for
the rest of the industry. Since there was no way to quantify this,
the three codes were not used in the projection.
The remaining codes involved in printing, together with a number of
employees, are:
Code Description Employees
2732 Book Printing 37,700
275 Commercial Printing 303,900
276 Manifold Business Forms 26,000
The interviews on this project were three in 2751, one in 2732, one
in 276 and one in 271 which turned out to be a small newspaper.
From previous projects there was one in 2732 and three in combined
operations 2732 and 275.
2. WASTE TYPES
It is characteristic of the industry that most of the actual process
waste, i.e. waste paper, is reclaimed. Only three out of ten
interviews had non-sold process wastes. However, when process
wastes were found, they constituted the major portion of the total
waste, averaging 92%. The remaining wastes were plant trash
shipping wastes, ink and glue and non-saleable paper. It is'typical
that the non-saleable paper is that which is coated, impregnated
or .otherwise made non-reclaimable. '
3. WASTE QUANTITIES
Of the three out of ten having non-sold reclaimable paper scrap
one had only a small portion of this scrap not sold, and the other
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two did not provide Kpye data. Accordingly, the Kpye's were
computed on the non-sold portion which means that they were almost
entirely the ''remaining wastes" mentioned in the previous para-
graph.
There was no trend of these waste/employee ratios with size of
establishment or among different sub-codes. The Kpye's were log-
normally distributed with a median of 1.85 Kpye and a a ratio,
taken to correspond to the population, of 3.68. If this is
characteristic of the entire population of some 18,500 establish-
ments, the average Kpye would be 4.53 and a 68% confidence interval
from 2.7 to 7.6 Kpye. Applied against the total number of employees
in Codes 2732, 275 and 276, this gives 1,660 million pounds per
year of waste for disposal.
When the more thorough general investigation of disposition and
disposal was made, it was recognized that the sold reclaimable paper
constituted a very large portion of the scrap and waste, and there-
fore, the two establishments that did not sell this reclaimable
paper might, through the projection, considerably increase the
quantity of waste for disposal. Accordingly, a new set of Kpye's
was computed taking all scrap and waste, both the reclaimable paper
sold and unsold and the remaining wastes. For these, the median
Kpye was 21.0, the a ratio 3.68 (the same as for the other), and this
would give an average Kpye of 51.4 with .a 68% confidence interval
from 29.4 to 90 Kpye.
Applied against the total number of employees in 2732, 275 and 276,
this gives 18,500 million pounds per year of scrap and waste. The
general disposition - disposal study in Section V indicates that
32% of the scrap and waste is waste for disposal and this gives
5,920 million pounds per year as waste for disposal. This is over
3.5 times as much as the waste for disposal projected on the basis
of the other Kpye's and indicates that the reclaimable but not sold
paper from the two plants out of ten, i.e. from a projected 20% of
the population, would greatly overbalance the small quantity of
"remaining" waste, plant trash, etc. from the other 80% of the
population. The quantities are such as to check this conclusion,
but it still must be presented with great reservation because the
difference 1,660 and 5,920 comes about through the operation of the
disposition - disposal pattern which is believed anyway to be quite
insecure. Of the two plants responsible, one is known to be a large
plant and the other is thought to be a large plant, so that the
unusual characteristic of not selling reclaimable paper cannot be
attributed to a small size of plant. It happens that both of these
plants are located in relatively small communities where possibly
the economics of the market dictate against sale of reclaimable
paper. However, there is no way to resolve this uneasy feeling about
the larger number and with the above reservation, it will be accepted
However, it also happens that none of the Code 275 interviews,
job printing shops, were in establishment of less than 250 employees
while about 75% of total employees in job printing shops are in such
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small establishments. For this reason, it was not felt warranted
to extrapolate the Kpye relation to low number of employees even
though it showed no trend at a high number of employees. Accordingly,
a separate projection was made in which the employees in Code 275
establishments having less than 250 employees were eliminated.
This reduces the 18,500 million pounds per year to 7,243 and the
5,920 million pounds per year to 2,318. The physical production
growth factor to 1975 is 1.39 and this projects the 1975 waste
production of the three codes to 8,250 million pounds per year and
of the three codes with the small job printing shops eliminated
to 3,222 million pounds per year.
4. DISPOSITION AND DISPOSAL
Disposition was by trucks and compactor trucks, three self, five
contractor and one city pickup. Ultimate disposal was three
incinerators (self owned), one open burning, one sanitary land fill,
three dumps and one unknown. The ownership of the ultimate disposal
facility was three self (the incinerators), three contractor owned,
two city and one unknown.
5. TRENDS
No trends in waste/employee or waste/product were revealed.
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SECTION VI
SURVEY RESULTS
U. TEXTILES
1. SUB-CODES AND INTERVIEWS
S.I.C. Code 22, "Textile Mill Products", comprises nine three-digit
sub-codes from which interviews were obtained in six as follows:
Code Description Employees Interviews
221 Weaving mills, cotton 208,820 2
222 Weaving mills, synthetics 86,785 2
223 Weaving mills, wool 45,528 1
225 Knitting mills 208,724 1
227 Floor covering mills 35,848 1
229 Miscellaneous 66, 001 3
The remaining three sub-codes in the two digit code are:
224 Narrow fabric mills 24,811
226 Textile finishing, ex. wool 73,129
228 Yarn and thread mills 106,599
Sub-code 224 was included among the projected codes because there
did not seem to be any reason by which it differed from the inter-
viewed codes. However, sub-codes 226 and 228 were judged to be
sufficiently different in the physical processing involved so that
it was not so secure that they shared the same Kpye with the others.
The number of employees in the projected codes is 677,600, some 79%
of the total employees in the two-digit code.
2. WASTE TYPES
The waste types included plant trash, shipping waste including
some metal baling ties, and process waste including cloth, yarn,
sweepings, cones etc. Not all establishments had process waste and
those that did have it did not show a particularly high Kpye com-
pared to the others. Process waste varied from 10% to 60% of the
total wastes in any establishments where they occurred.
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3. WASTE QUANTITIES
Among the ten Kpye's there was no trend with employee size and no
indication of any variation with the interviewed sub-codes except
that the Kpye's for 229, miscellaneous, were on the high side. No
physical reason could be attached to this and, therefore, these
Kpye's were included in the distribution with the others. The
Kpye's were log-normally distributed with a median of 2.11 Kpye and
a a ratio of 3.03. If these are the characteristics of the
population of some 7,000 establishments, the mean Kpye would be 3.8£
and a 68% confidence interval from 2.6 to 5.7. Applied against the
number of employees in projected codes, this gives 2,629 million
pounds per year for scrap and waste.
The disposition - disposal analysis, Section V, indicates that the
waste for disposal is some 65% of scrap and waste, practically all
the remainder being sold. This gives 1,706 million pounds per
year for waste for disposal and at a growth factor of 1.25,
2,132 million pounds per year waste for disposal in 1975.
4. TRENDS
None of the interviews foresaw any trends in waste/product ratio in
the next ten years.
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SECTION VI
SURVEY RESULTS
V. APPAREL
1. SUB-CODES AND INTERVIEWS
S.I.C. Code 23, "Apparel and Related Products", is comprised of
nine three-digit sub-codes from which interviews were conducted in
four as follows:
Code Description Employees Interviews
231 Men's and boys' suits and coats 120,457 1
232 Men's and boys' furnishings 307,876 4
233 Women's outwear 407,748 3
234 Women's undergarments 113,633 1
Three of the remaining codes were considered similar enough in pro-
cessing to be included in the projected codes as follows:
236 Children's outwear 77,865
238 Miscellaneous apparel and 60,948
accessories
239 Fabricated textiles, n.e.c. 148,225
The total employees in projected sub-codes are 1,238,354, some 97%
of the total in the two-digit code from which there remains as
unprotected codes:
235 Hats, caps, millinery 33,204
237 Fur goods 8,066
2. WASTE TYPES
In addition to plant trash and some shipping waste, seven out of the
nine interviews showed some process waste comprising rags, cloth
scraps, cuttings, etc. For those that had process scrap, these
average 43% of total scrap and waste, about two-thirds of this scrap
being sold.
3. WASTE QUANTITIES
The seven Kpye's showed no trend with employee size and no reason
for distinguishing among codes interviewed. The Kpye's were log-
normally distributed with a median of 0.51 Kpye and a a ratio of 2.61
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If these are the characteristics of the population of 26,261
establishments, the mean Kpye would be 0.79 and the 68% confidence
interval ranges from 0.55 to 1.13. Applied against the indicated
number of employees in projected codes, this gives a scrap and waste
for projected codes of 981 million pounds per year.
The disposition - disposal analysis in Section V indicates that
29% of the scrap and waste is utilized, leaving 696 million pounds
per year as waste for disposal. With an indicated growth factor
of 1.49, this becomes 1,037 million pounds per year in 1975.
4. TRENDS
None of the interviews saw any trends in production pattern which
would alter the waste/product ratio in the next ten years.
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SECTION VI
SURVEY RESULTS
W. FABRICATED METAL PRODUCTS AND MACHINERY EXCEPT ELECTRICAL
1. SUB-CODES AND INTERVIEWS
These two two-digit codes are handled as one through the following
circumstance. One of the four-digit codes, 3411, metal cans,
showed a higher Kpye than the remainder of Code 34. However, this
remainder of Code 34 had a distribution which was indistinguishable
from the distribution of Code 35. Since Code 34 and Code 35 have
a quite similar type of processing as well as material, they were
combined as a single code group, with Code 3411 as a separate code
group due to the higher Kpye. The sub-codes and interviews were
as follows:
Code
3411
342
343
344
351
352
353
354
356
Description
Metal cans
Cutlery ; hand tools
Plumbing and non-electric heating
Fabricated structural metal products
Engines and turbines
Farm machinery
Construction machinery
Metal working machinery
General industry machinery
Employees
53,745
139,336
72,467
316,559
89,217
120,797
220,950
272,053
240,998
Interviews
3
3
1
3
1
4
3
1
1
Included in the projected codes were the remaining non-interviewed
sub-codes in Code 35 as follows :
355
357
358
359
Special industry machinery
Office machinery, n.e.c.
Service industry machinery
Not elsewhere classified
173,844
156,281
112,163
140,072
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There remain the following sub-codes in Code 34 which were placed
in the non-projected codes because they had no interviews and it was
not clear that they would have the same Kpye's as the interviewed
codes:
Code Description Employees Interviews
345 Screw machine products and bolts 93,502
346 Metal stampings 135,239
347 Coding and gravings 64,981
348 Fabricated wire products, n.e.c. 55,795
349 Not elsewhere classified 148,203
2. WASTE TYPES
Typical waste types in all interviews were plant trash, shipping
waste, and metal scrap. Typically, the metal scrap was a large
fraction of the scrap and waste, averaging about three-quarters of the
total.
3. WASTE QUANTITIES
For Code 3411 the three Kpye's had a median of 18.1 and a a ratio
of 1.11. If this is taken as characteristic of the 259 establish-
ments in the nation, the average Kpye would be 18.1 and the confidence
interval thereon from 16.6 to 19.7- Applied against the 53,745
employees, the scrap and waste is 973 million pounds per year.
The remaining eighteen interviews in the rest of Codes 34 and 35
were log-normally distributed with a median of 3.16 and a a ratio
of 3.09. If this is characteristic of the population of more than
25,000 establishments, the average Kpye would be 6.00 and the 68%
confidence interval thereon from 4.6 to 7.9. Applied against the
2,056,286 employees in the projected sub-codes, this gives 12,337
million pounds per year of scrap and waste.
The disposition - disposal analysis indicates that 81.2% of scrap
and waste from 3411 is utilized and 51.2% from the remainder of the
projected sub-codes is utilized. On this basis, the waste for
disposal for 3411 is 183 million pounds per year for 1965 and with
a growth factor of 1.41, 258 million pounds per year in 1975. For
the remainder of the projected codes, the 1965 waste for disposal
is 6,020 million pounds per year and with a growth factor of 1.47
becomes 8,758 million pounds per year in 1975.
4. TRENDS
None of the interviews produced any evidence for changes in pro-
duction practices which would alter the waste/product ratio in the
next ten years.
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SECTION VI
SURVEY RESULTS
SPECIAL WASTE TYPES
Two studies were made of special waste types common to a number of
codes. One of these studies investigated plant trash and shipping
waste, which to some degree,, at least occur in all establishments. For
this study there were available ten points giving shipping waste alone,
twenty-nine giving plant trash alone, and thirty-three giving plant
trash plus shipping waste. These three categories of Kpye's had log-
normal distributions with characteristics shown in the following table.
Number
of Kpye _o_
Points Median Rat_io_ X Mean CI
Shipping 10 .47 4.46 1.45 (0.9-2.4)
Plant trash 29 .66 3.18 1.29 (1.0-1.6)
Plant trash & shipping 33 2.67 3.75 6.54
Plant trash & shipping 39 5.96 (4.7-7.6)
These Kpye's showed no trend with number of employees or with two-digit
codes among the seventeen codes from which they were drawn. Codes
excluded from this study were:
Printing and Publishing Demolition Asphalt Roofing
Cotton Ginning Saw Mills Stockyards
Super Markets
These were codes which either do not have shipping wastes or plant
trash or in which these were not identifiable as such, especially not
identifiable among a relatively huge quantity of process wastes. Most
of the super market wastes are indeed shipping wastes since they consist
of the cardboard boxes in which the incoming stock is received.
The distribution curve for the ten shipping waste points did not fit
in with the other two categories in that the a ratio was much higher, and
the sum of the medians for shipping waste and plant trash was sub-
stantially less than the median for plant trash plus shipping waste,
the same being true of the A means. It was concluded that one of the
three sets of data points was anomalous, and this was first taken to be
the shipping waste points since these had the lowest number of points
and the highest a ratio. This would leave it preferable to project
shipping waste as the difference between plant trash plus shipping
waste and plant trash alone.
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The A mean figure of 6.54 for plant trash plus shipping waste is that for
the thirty-three points having both plant trash and shipping waste data.
However, the ten shipping waste points included six points for which
plant trash was not available and thus, which do not appear in the
thirty-three plant trash plus shipping waste distribution. The distri-
bution of the six points was practically the same as the distribution
for the ten points. Thus, their A mean is about 1.45 and since all
establishments have plant trash, they must be assumed to have a A mean
of plant trash of 1.29. Thus, the A mean for the sum of shipping waste
and plant trash waste for these six plants is 2.74; in other words,
substantially less than the A mean of the thirty-three plants having
plant trash plus shipping waste. However, these six establishments are
still part of the total sample of thirty-nine establishments, and when
the A mean for the thirty-nine is computed by properly weighing the six,
the A mean becomes 5.96.
Thus, the average plant trash is 1.3 Kpye and the approach just described
would leave the average plant trash plus shipping waste as 6.0 Kpye, and
the difference or 4.7 Kpye would represent shipping waste alone. But the
national average Kpye is only 5.56 and therefore, it is concluded that
the figure of 6.0 generated above must be non-representative and the
discrepancy is not resolvable. The figure of 1.3 Kpye for plant trash
is reasonable and acceptable, however.
It may be noted that the average manufacturing employee generates as
plant trash, i.e. as office papers, lunch scraps and containerss coffee
cups, paper towels and other sanitary items, newspapers, etc. just about
as much solid waste during his working year as his assigned per capita
generation while at home.
The second study on special waste types was concerned with metal wastes
which are prevalent in Codes 34, 35 and 36. These were studied
separately, separating out Code 3411, metal cans, which has its own
special characteristics. The study was undertaken primarily in order to
be able to fill in missing metal waste figures for certain establishments
in these codes in order to generate a usable Kpye figure for every
interviewed establishment.
The statistical characteristics of the Kpye's for. metal waste alone,
for those establishments having metal wastes, are shown in Table VIII.
The points for Code 36 could not be considered log-normally distributed.
Also shown for comparison are the A mean figures for Kpye total waste
for the corresponding codes, drawn, it may be noted, from a greater
number of establishments than contained in the metal waste analysis.
Because of the latter circumstance, it is not proper to assume that the
average fraction of metal waste in total scrap and waste is given by the
ratio of the last two columns. However, the ratio is of the proper
general magnitude as shown by Table IX.
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TABLE VIII
KPYE METAL WASTE
A A Mean Total
Code Points Median Ratio Mean, CI Scrap & Waste
3411 3 14.60 1.22 15.9(13.6-18.6) 18.1
34 (ex. 3411) 8 .97 6.65 5.97(2.8-12.6) 6.0
35 7 1.15 1.81 1.39(1.1-1.8)
36 5 .751 7.10 1.59* 2.75
Distribution cannot be considered as log-normal;
arithmetic mean of sample used instead.
TABLE IX
A Mean Metal Waste Kpye Av. Fraction _ Metal Fraction
Cgde_ A Mean Scrap & Waste Kpye Metal Vlaste Total Utilized
3411 0.88 0.81 0.81
34 (ex. 3411) 0.49
} 0.61 0.51
35 0.60
36 0.58 0.43 0.24
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The last column in this table shows the fraction of the scrap and
waste which is utilized. The explanation for the similarities and
differences between the last and next to the last columns is that,
although in all three code groups practically all of the metal waste
is sold, yet in Code 36 a substant'al fraction of the establishments
do not have metal waste, the 0.43 being the fraction metal waste in total
waste for those establishments having metal waste.
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SECTION VII
GENERAL DISPOSITION - DISPOSAL PATTERNS
The individual code sections have given information on disposition and
disposal mode frequencies indicating merely the frequency of occurrence of
indicated disposition and disposal modes. The categories covered were dis-
position agent, ultimate disposal or reduction facility type and ultimate
disposal or reduction facility ownership. In a few code sections this
disposition - disposal analysis was carried further by the "intermediate"
method of average percentages in order to be able to eliminate from the Kpye
data certain disposition or disposal modes which did not result in waste
for disposal. In certain other individual code sections, adjustments to
Kpye data and X mean projections have been made using disposition - disposal
percentages computed in this section.
This section reports a general study of disposition - disposal patterns
made for each code separately. The results have also been combined for
various presentation purposes and uses.
A. DEFINITIONS
In order to discuss the subject, it is necessary to introduce some new
definitions concerning waste paths and waste, disposal in industrial
establishments. Figure 5 shows the possible flows of industrial scrap
and waste and serves to illustrate the definitions.
1. SCRAP-AND-WASTE
Solid materials generated by an establishment other than the material
which leaves as the primary product. While not used in the
unhyphenated form the term "scrap" is intended to apply to process
residues and the term "waste" is added to convey also the concept
on non-process materials. Scrap-and-waste is the material which is
a potential waste for disposal.
2. UTILIZED SCRAP-AND-WASTE
Scrap-and-waste which is utilized in some way and is not subject to
ultimate disposal.
3. UNUTILIZED SCRAP-AND-WASTE
Scrap-and-waste requiring ultimate disposal or waste reduction and
disposal.
4. BY-P_RQDUCT
A means of utilizing scrap-and-waste restricted to process scrap,
fabricated or unfabricated, which is sold or given directly to a
customer for a specific use.
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FLOW PATTERN FOR INDUSTRIAL SCRAP-AND-WASTE
Scrap-and-Waste
I
h-'
O
I
Utilized
I
Unutilized
By-Product
In-Plant
Commercial
Salvage
Misc., n.e.c.
including
Non-Commercial
Salvage
I
Waste
For
Disposal
Sewer-
Borne
I
From
Excluded
Industry
Recycled Fuel
Figure 5
-------
5. C OMMERCIAL_SALVAGE
A mode of utilizing scrap-and-waste by which it enters the com-
mercial scrap market.
6. IN-PLANT UTILIZATION
Modes of utilizing scrap-and-waste which are accomplished within
the generating establishment,
7. FUEL
In-plant utilization of scrap-and-waste for fuel.
8. RECYCLED
In-plant utilization of scrap-and-waste by recycling it to the
process.
9. MISCELLANEOUS UTILIZATION
Utilization of scrap-and-waste in other ways, including that sold
or given away to individuals for non-commercial purposes.
10. WASTE-FOR-DISPOSAL
For the purposes of this project, only that portion of the
unutilized waste which falls in the category defined in the scope,
namely unutilized waste excluding that from certain industries and
excluding that which has a sewer-borne disposition and disposal.
11. UTILIZATION ACHIEVEMENT
The degree of success in utilization of scrap-and-waste, numerically
the fraction:
Cl _ waste-for-disposal, mpy
scrap-and-waste, mpy
B. OBJECTIVES
The objectives of this section are:
1. To provide quantitative information on disposition and disposal
modes for the total of the twenty code groups covered.
2. To provide for each code quantitative data showing the fraction of
scrap-and-waste which the industry has succeeded in utilizing,
i.e. the utilization achievement.
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C. LIMITATIONS OF THE BASIC DATA
As may already have been learned from the individual code chapters, the
second objective above was not at all provided for in the data collection
plan. Where scrap-and-waste had a nearly universal utilization,
information on its quantity was not actively sought since it was not to
be used in the projection of waste-for-disposal. For example, many food
sub-codes have scrap-and-waste which is utilized as by-product, e.g.
animal feed. The meat packing industry has found it possible through
the years to utilize more and more of the animal as by-product such
that such materials have not for several generations been considered
among scrap-and-waste. In the saw mill industry, it is common to sell
chips as by-products in the East and to burn scrap-and-waste for fuel
in the West. In the printing and publishing industry, a very large
percentage of the total scrap-and-waste is scrap paper utilized as
by-product or via commercial salvage. While the collection of infor-
mation on these conventionally utilized materials was not part of the
project plan, it happened that in a surprising number of the inter-
views such information was actually collected.
A second and much more serious deficiency of the data is the small size
of sample bearing on disposition - disposal incidence and percentages.
This is the case despite the fact that the interviews have been supple-
mented with the postcard disposition data previously collected which
incidentally usually gave only the disposition pattern for the non-sold
scrap-and-waste since this is the way in which the question was
phrased. As has been shown with waste/employee ratios, it is possible
to achieve secure projections from a small sample if the population
happens to have some uniform and known characteristic distribution,
and a distribution brought about by completely random influences.
However, the nature of disposition - disposal patterns and basic
causes is such that a very large sample is required for an adequate
projection. The reason for this may be illustrated as follows.
Attention may be focused on two codes as to the question whether one
code tends to municipal pick-up while the other tends to self disposition.
If a municipality offers free municipal pick-up to industrial establish-
ments, most establishments, of course, will avail themselves of this
and in that city there will be very little industrial contractor
disposition. At the same time in another city, the municipal regulations
may prohibit municipal pick-up of industrial waste and accordingly
some industries will use self disposition and some contractor disposition.
If contractor rates are very high in this city, most industrial
disposition will be self disposition.
Now if one surveys a large number of cities, and therefore, a large
number of establishments, for these two codes and all cities that fall
into one or the other of the two categories, then he will find that the
fraction disposing by one or the other of the modes (municipal or self)
is approximately equal to the fraction in which the industry is present
in the two types of cities. However, if one has in the sample only a
few establishments, say six to twenty, then there is a good chance that
most of the establishments in one code may come from one type of city
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and most in the other from the other type. The disposition pattern for
the two industries would not be characteristics of the industries
themselves at all, but rather the characteristics of the cities in
which the sample happened to be concentrated.
A similar situation can be visualized, again for illustration, if one
considers for example, the fate of wastes, from restaurants. These may
be picked up by the municipality or may have contractor disposition but
in either case, let it be assumed that the ultimate disposal is in the
city facility. Then the fraction of restaurant wastes going to
incinerators as against sanitary land fills will depend upon whether
the sample came from cities largely with incinerators or from cities
largely with sanitary land fills.
Stating the situation, in general the disposition - disposal modes for
establishments in samples of the size available to the study, depend
upon the geographical, economic and political situation in the cities
interviewed and have a high degree of dispersity. The only projection
which can be secure, therefore, is one in which the sample size is very
large so as to assure coverage of all the varying degrees and types of
dispersity.
Implicit in the foregoing discussion is the concept that the S.I.C. Code
really does not have a great influence on disposition mode. If sanitary
land fills are.common in a city, most wastes from all codes with some
obvious exceptions will be disposed of by sanitary land fill. If, on
the other hand, sanitary land fills are uneconomic and incinerators are
the practice, most wastes from all codes will be disposed of by incineration.
Indeed, it might be guessed that one would get a more accurate picture
of the fate of industrial wastes, not self disposed, by considering
the nation's capability in non-private dumps as compared with non-
private incinerators than by making a survey of individual disposition
and disposal in industrial establishments themselves.
A further corollary to these concepts is that a more accurate disposition -
disposal pattern for each individual code would be achieved by summing
the patterns for all 320 interviews in all 24 codes than by taking
those restricted to the individual code itself. The reason is that the
larger 24 code sample would contain the dispersity which the individual
code sample did not.
The enabling assumption upon which the above remarks are based is that
there are no differences in disposition pattern as a function of code.
This assumption could no doubt be tested statistically and would be
more likely to be capable of such testing if the sample size were
larger in each code, but we do not presume to undertake this statistical
test which is difficult enough even with an adequate sample size.
Rather, we make a virtue out of a necessity and since the second
objective requires a disposition analysis and projection by individual
codes, the entire disposition analysis has been based on individual
codes, although they are summed for the final presentation. In general,
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the disposition - disposal results must be considered of considerably
lower accuracy as an estimator of the national population they are
the waste-for-disposal quantities.
D. PROCEDURE
Each one of the 320 interviews for the twenty-four codes and each of the
eighty-five postcards for these codes was reviewed to determine the
fraction having various disposition and disposal modes and also to
determine the fraction of the total scrap-and-waste which had not
entered into the waste/employee or waste/product ratios developed in the
individual chapters. However, not all of these 405 interviews and
postcards supplied disposition - disposal data so that only 305
individual cases were utilizable. These do not count the 4,865 cotton
gins on which the pattern for that code is based. The postcard survey
developed only the disposition of the non-sold scrap-and-waste so the
fraction sold was developed only from interviews while the fractions
and frequencies having other dispositions were developed from both
interviews and postcard data.
For each code the fractions were averaged among all the establishments
as divided among some 37 disposition - disposal modes. The average
percentage to each disposition mode was obtained using the method
described as the ''intermediate method" in the procedure (see Appendix C).
The disposition - disposal modes actually encountered in the sample
and for which percentages were computed are listed in Table X. There
are a number of other possible combinations of the three modes, but
those not listed were not actually encountered. It is seen that
summations can be made in any desired category; for instance, all
waste that is incinerated, all waste that is contract hauled, all waste
that goes to a municipal owned ultimate disposal facility.
One of two methods was used to generate scrap-and-waste from the
original Kpye or other figure used in the individual code chapters.
One of these was applied when some single waste stream had been eliminated
from the Kpye's because of some universal disposition such as sold,
recycled, etc. The other method, used only for wooden boxes and for
printing and publishing, was applied when it was not possible to
separate out a single previously not accounted 'for stream in this way.
In those cases, a new set of Kpye's was computed based on scrap-and-
waste and the projections made with these just as described in the
individual chapters, yielding a new figure for scrap-and-waste in contrast
to the previous figure developed in the chapter.
D. RESULTS - PROJECTED CODES
The scrap-and-waste quantities thus projected and the utilization
achieved are shown in Table XI. It is seen that the total scrap-and-
waste for the 24 code groups projected is 350,500 million pounds per
year, or excluding saw mills, about 157,900 million pounds per year.
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TABLE X
DISPOSITION - DISPOSAL MODES ENCOUNTERED'"
Self-owned ultimate disposal facility
Incinerator or burner
Dump - self haul
Dump - contract haul
Open burn
Sanitary land fill
Fill
Municipal-owned ultimate disposal facility
Dump - municipal haul
Dump - self haul
Dump - contract haul
Incinerator - municipal haul
Incinerator - self haul
Incinerator - contract haul
Sanitary land fill - self haul
Sanitary land fill - contract haul
Ultimate disposal type unknown - municipal haul
Ultimate disposal type unknown - self haul
Ultimate disposal type unknown - contract haul
Contractor-owned ultimate disposal facility
Sanitary land fill - self haul
Dump - self haul
Dump - contract haul
Open burn - contractor haul
Sanitary land fill - contractor haul
Type of ultimate disposal unknown - contract haul
Type of ultimate disposal unknown - municipal haul
Merchant ultimate disposal facility
Dump - self haul
Dump - contract haul
Ownership of ultimate disposal facility unknown
Dump - self haul
Dump - contractor haul
Type of ultimate disposal unknown - self haul
Type of ultimate disposal unknown - contract haul
Type of ultimate disposal unknown - hauler unknown
Not waste-for-disposal
Give-away -- at plant site
Give-away - self haul
Give-away - contract haul
Fuel - in plant
Sold - self haul or at plant site
Sold - contract haul
Sewer
* Modes not encountered in the sample are not listed.
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The last column in Table XI shows the total waste-for-disposal. The
total is 181,500 million pounds ner year or with saw nills omitted,
115,900 million pounds per year.
It is seen that some industries ,._ .eve a very high utilization of
scrap-and-waste, these being cotton at 59 percent, mostly by return to
the land as soil amendment; wooden boxes at 50 percent, viostly through
sale of chips; saw mills at 66 percent by sale of chips and use of
bark, slabs and sawdust for fuels; auto and aircraft at 50 percent,
mostly by direct give-away at the plant site: stockyards at 60 percent
by utilization for fertilizer; super markets at 40 percent, mostly by
entering the commercial salvage stream; mill work at 47 percent, mostly
by F.O.B. sale; and printing and publishing (greater than 250 employees)
68 percent, mostly as by-products or commercial salvage. As can be
expected, fabricated metal products and machinery- except electrical,
show a high fraction utilized, 81 percent for metal cans and 51 percent
for the remainder of these two codes because most of their scrap-and-
waste is metal scrap which readily finds utilization in the commercial
salvage market. Meat packing is found listed at 44 percent, but this
actually is 44 percent which did not enter the waste-for-disposal as
defined. It was flushed to sewers.
Overall, 24 code groups, 48 percent of the scrap-and-waste does not
enter the waste-for-disposal stream and 52 percent becomes waste-for-
disposal. Over 23 code groups (except saw mills) about 73 percent is
waste-for-disposal and 27 percent is utilized. The twenty manufacturing
code groups alone have an even higher utilization of 56 percent but
again this largely reflects the high utilization and high contribution
of saw mills 5 being at 31 percent without this code.
Of the 48 percent not entering the waste-for-disposal stream, the greatest
is sold with 29 percent out of the 48 percent. Next is fuel, 17 percent
and finally give-away with 2 percent out of 48 percent. For the 19
code groups excluding saw mills sold is about 21 percent out of 26 percent,
give-away 4 percent and fuel only 1 percent out of the 26. These
figures indicate the great importance of fuel utilization in the saw
mill industry. In dealing with the overall picture as for the twenty
code groups, it should be recalled that the twenty code groups include
four codes not in the manufacturing industries, namely cotton ginning,
demolition, stockyards, and super markets. Also, it should be recalled
that the remaining 16 code groups in manufacturing do not include all
of manufacturing.
The remainder of this discussion concerns the waste-for-disposal
namely the 181,543 million pounds per year for the twenty-four code
group or the 115,943 for the twenty-three code group excluding saw
mills. Table XII shows the distribution in million pounds per year of
waste for disposal among various disposition - disposal modes, both
for the twenty-four codes and for the twenty-three codes, excluding
saw mills, which make such a large contribution to the total and have
a special characteristic disposition - disposal mode.
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TABLE X I
SCRAP-AMD-WASTE QUANTITIES AND UTILIZATION ACHIEVED
S.I.C. Code Group
Number of Interviews
And Postcards
Supplying Disposition,
Disposal Information
Known Scrap and Waste
1965
Million/lbs/yr
Fraction Utilized
or Otherwise Not
Waste-For-Disposal
Waste-For-Disposal
1965
Million/lbs/yr
MANUFACTURING
Food
Meats
Textile Mill Products, ex. 226, 8
Apparel & Related Products, ex. 235, 7
Wooden Containers
Saw Mills
Mill Work
Wooden Furniture
Paper
Printing & Publishing
Chemicals
Paints
Asphalt Roofing
Rubber
Tanning
Glass
Metal Cans, 3411
Fabricated Metal Products & Machinery
ex. Electrical, 34 ex. 3411 ex. 345, 6, 7,
8, 9, & 35, ex. 364
Electrical Machinery
Auto & Aircraft
Sub Total, 20 Manufacturing Code Groups
Sub Total, 19 Manufacturing Code Groups
(except saw mills)
14
10
10
9
40
65
9
14
42
9
11
8
7
11
7
7
3
18
20
9
11,500
2,963
2,629
981
4,996
192,600
1,072
4,197
11,100
7,243
2,625
324
1,180
2,900
608
3,200
973
12,337
3,651
5,786
272,865
80,265
0.08
0.44
.351
.291
0.51
0.66
0.47
0.26
0.10
0.68
0
0
0.03
0
0.02
0.16
.812
.512
.244
0.50
.56
.31
120,782
55,182
NON-MANUFACTURING
Cotton Ginning
Demolition
Stockyards (including auction)
Super Markets
Total, 24 Code Groups
Sub Total, 23 Code Groups (except saw mills)
(4865)
8
11
11
293
3,836
38,100
1,919
33,800
350,520
157,920
0.59
0
0.61
0.40
.48
.27
181,543
115,943
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The totals in Table XII and following tables do not correspond exactly
with those in Table I . The differences arise from a recomputation of
the data from which Table I was obtained, but the magnitude of the
difference is negligible (about .6%) in view of the overall confidence
interval of these figures.
Under disposition agent it is seen that about half of the waste is
handled at the establishment site by the generator and an additional
quarter of the waste is handled by the generator by hauling off the
plant site. Contract disposition accounts for 21 percent. When saw
mills are excluded, only about 22 percent is handled at the site and
30 percent is self hauled off the plant site. The contract share is
about 33 percent.
As to type of ultimate disposal facility, incinerators and burners are
about equal with dumps, each around 40 percent, with other modes much
smaller in importance. With saw mills excluded, dump is the major mode
with 57 percent followed by incinerator or burner and sanitary land fill
with considerably smaller percentages.
As to ownership of the ultimate disposal or reduction facilities,
private ownership is predominant with 50 percent followed by municipal
with about 36 percent. When saw mills are excluded, the private owner-
ship falls to 22 percent of that total and municipal becomes the major
mode with 56 percent. Contractor or merchant disposal is quite minor.
It is of interest to specify how much of the material going to self-
owned facilities is handled by the various types of facilities. This
is shown in Table XTTT. It is seen that incinerator or burner is the major
type being 76 percent, dump being 18 percent and other modes of very
minor importance. Excluding saw mills, the incinerator or burner still
maintains predominance with 62 percent and dumps become 25 percent, open
burning gaining some in importance. The difference between the
69,759 million pounds per year for the twenty-four codes and the 15,831
million pounds per year for the twenty-three cooes shows the predominance
of incinerator or burner as a disposal mode in the saw mill industry.
Another breakdown of interest describes the fate of industrial waste
having contract disposition. This is shown in Table XIV for the 38,379
million pounds per year having contract disposition. Fifty-three percent
of the contract disposed waste is known to go to municipal ultimate
disposal or reduction facilities, but there is a large unknown component.
If the unknown component is distributed in the same way as the three
known components, the percentages would be self 1.1 percent, municipal
77.1 percent, contractor or merchant 21.8 percent. This indicates that
77 percent of the industrial waste collected by contractors goes to a
municipal ultimate disposal or reduction facility, and only 22 percent
to contractor or merchant facilities. The 1.1 percent self-owned
facilities represent that portion of the industrial waste which is
hauled by contractors to the generator's own disposal facility, a
quite negligible amount.
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TABLE XII
DISTRIBUTION OF WASTE-FOR-DISPOSAL AMONG
VARIOUS DISPOSITION - DISPOSAL MODES_
Projected Codes
Manufacturing Plus Non-Manufacturing
DISPOSITION AGENT
Twenty-Four Codes
Million/Ibs/yr Percent
Twenty-Three Codes
(Excejot_ Saw Mills)
Million/Ibs/yr Percent
Self (at site)
Self (remote)
Contract
Municipal
Unknown
Total
90,895
45v806
38,379
6,386
1,247
182,713
49.7
25.1
21.0
3.5
.!_
100.0
25,411
45,806
38,379
6,386
669
116,651
21.8
39.3
32.9
5.5
._5_
100.0
TYPE OF ULTIMATE DISPOSAL OR REDUCTION
Incinerator
and Burner 74,058
Dump 76,316
Sanitary Land Fill 14,380
Open Burn 4,555
Fill 424
Unknown 12,978
Total 182,711
40.
41.
7.9
2.5
.2
7.1
100.0
20,130
66,686
14,380
2,629
424
12,400
116,652
17.3
57.2
12.3
2.3
.4
10.5
100.0
OWNERSHIP OF ULTIMATE DISPOSAL AND REDUCTION FACILITIES
Self
Municipal
Contract or
Merchant
Unknown
Total
91,186
65,308
11,654
14,563
182,711
49.9
35.7
6.4
8.0
100.0
25,703
65,308
11,654
13,985
116,650
22.0
56.0
10.0
12.0
100.0
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TABLE XIII
DISTRIBUTION BY ULTIMATE DISFOSAL_OR.
REDUCTION TY7Z FOR CSLF-OWNED FACILITIES
Projected Codes
Manufacturing Plus Non-Manufacturing
Incinerator or
Burner
Dump
Sanitary Land Fill
Open Burn
Fill
Unknown
Total
Twenty-Four Codes
Million/lbs/yr Percent
69,759
16,039
111
4,193
424
0
91,186
76.5
17 .6
.8
4.6
.5
0
100.0
Twenty-Three Codes
Million/lbs/yr Percent
15,831
6,409
771
2,267
424
0
25,702
61.6
24.9
3.0
8.8
1.7
0
100.0
TABLE XIV
DISTRIBUTION BY OWNERSHIP OF ULTIMATE DISPOSAL OR
REDUCTION FACILITIES OF INDUSTRIAL WASTE HAVING CONTRACT DISPOSITION
Projected Codes
Manufacturing Plus Non-Manufacturing
Twenty-Four Codes
Million/lbs/yr Percent
Self
Municipal
Contractor or Merchant
Unknown
Total
291
20,471
5,801
11,816
38,379
53.3
15.1
30.8
100.0
Twenty-Three Codes
Fl_ll_ion/lbs /yr Dercent
291
20,471
5,801
11,816
38,379
.8
53.3
15.1
-JUil
100.0
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The data on the frequency of occurrence of the various disposition -
disposal modes also suffers from the sirallness of the sample compared
with the dispersity of the population. As with the disposition -
disposal percertages, the results o;. Evaquencies are presented as the
best information as yet available. The frequencies simply indicate the
total number of times in which each disposition - disposal mode was
encountered in the interviews. This gives no information on the
quantities of waste so handled since the use of an incinerator to
incinerate 3 percent of an establishment's total wa.ste would receive a
tally of one, and the use of a dump to dispose of the remaining 97 per-
cent would also receive a tally of one. This information may be useful
for those wishing to form a general (and very preliminary) idea of just
how many sales possibilities there might be for tepee burners, for
example. Looked at in another way, the frequencies give the probability
that any particular establishment chosen at random would have the
particular disposition - disposal mode described. The results for the
approximately three hundred occurrences are shown in Table XV.
It is noted that the frequencies of occurrence of the various modes
parallel the percentage of the waste-for-disposal to the corresponding
modes from. Table XLL This suggests that frequency-, which is much
easier to determine, might be used as an estimator of percentage in
future studies, and this is worth some exploration.
TABLE XV
FREQUENCIES OF DISPOSITION - DISPOSAL MODES
Projected Codes
Manufacturing Plus Non-Manufacturing
BY DISPOSITION AGENT
Percent of Occurrences
Self
Municipal
Contract
Unspecified Not-Self
BY TYPE OF ULTIMATE DISPOSAL OR REDUCTION
Tepee Burner
Incinerator
Open Dump
Open Burn
Sanitary Land Fill
Unknown
BY OWNERSHIP OF ULTIMATE
60
7
31
DISPOSAL AND PEDUCTION FACILITIES
Self
Municipal
Contractor
Merchant
Unspecified Not-Self
1.2
17,
19.
47,
5.
10.
not counted
48.
37.
2,
4.
7.0
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Tables and discussion similar to the preceding covering disposition -
disposal for projected and non-projected codes combined will
in the "Non-Projected Codes" chapter.
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SECTION VIII
NON-PROJECTED MANUFACTURING CODES
This study has been largely confined to the manufacturing industries, S.I.C.
Codes 19 - 39, with four additional industry codes included because it was
thought they might have a high quantity of waste and a waste problem
physically similar to those of the manufacturing industries.
If the authors were asked: "What solid wastes has your study missed?'' they
would first have to refer to the scope of the contract. This contract
excludes certain activities which probably generate a very large quantity
of solid waste. For example, the scope of the project excludes mining
wastes, and farm and forest wastes such as agricultural and logging residues.
The area studied can be approximately defined as those solid wastes generated
in establishments physically resembling manufacturing establishments and
which have a reasonable possibility of some interaction with municipal
wastes. Such a definition provides for the inclusion of the four non-
manufacturing codes studied; cotton ginning, demolition, stockyards and
super markets, but it also permits the inclusion of a number of other
industries not studied in the project such as contract ccnstruction and
automobile scrapping. For some of these industries which are outside the
scope of the project, the quantities are known. For example, the solid
waste in automobile scrapping is of the order of 18,000 million pounds per
year, or about 0.25 pounds per capita per calendar day. Nevertheless, the
authors cannot hazard a guess as to how much has been missed because of
insufficient knowledge of the codes which were not covered.
This reservation does not apply to the "non-projected1" codes and sub-codes
in the manufacturing division, for there it is perfectly definite as to
which sub-codes have not been covered. They consist of all sub-codes not
listed as projected codes in Table I. While not called for in the scope
of work for this project, it was thought to be desirable to make an estimate
of the waste for disposal in these 'non-projected" codes. The 1964 ''County
Business Patterns" reports 16,050,119 employees in the manufacturing division
excluding administrative and excluding S.I.C. Codes 29, Petroleum, but
including 2952, Asphalt Roofing. Of these, only 10,146,132 have been covered
in the projected codes. This chapter attempts to estimate the waste for
disposal generated by the remaining approximately 5,900,000 employees in
manufacturing.
A. METHOD
The method of projection will be to assign a Kpye to the non-projected
codes and to compute the amount of waste from the known number of employees;
therein. Some of the Kpye assignments are drawn from actual interviews
conducted from prior proprietary Combustion Engineering projects, but
for certain technical reasons, non-projected in the study. For example,
Kpye figures are known for the seven non-projected sub-codes in the food
industry, and indeed they were excluded from the interviews in the
present project because the prior information indicated that the waste
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quantities would be very low. Most of the Kpye assignments, however,
are estimates based on similarities in materials and processing between
unknown, non-projected codes and known interviewed codes. It is pointed
out that some of the projected codes themselves are non-interviewed
codes which have been assigned the Kpye of the interviewed codes on
the basis of strong and close similarities between them and the inter-
viewed codes. For the non-projected codes in this chapter, the
similarity is less strong and therefore the Kpye assignment less secure.
That it is a knowledgeable estimate rather than a random guess can be
demonstrated by actual project work which provides some measure of the
validity of the estimates to be made. After the twenty codes had been
studied, in the first stage of this project, the very question: "How
much have you missed?" was investigated for the purpose of making an
intelligent selection of additional codes to be interviewed in the second
stage of the project. On the basis of similarities to the interviewed
codes, Kpye's were assigned to the then non-projected codes, which when
applied to the non-projected employees, produced an estimate that
41,700 million pounds per year had been missed in the non-projected
manufacturing codes.
These estimated individual code mpy's were used as one of the bases
for selecting the additional codes to be interviewed in the second stage.
These additional codes were S.I.C. Codes 22, 23, 34, 35 and 36. In
Code 36, five, 4-digit sub-codes had already been interviewed and pro-
jected. The estimated quantity missed in these five codes to be added,
using the above procedure, was 9,403 million pounds per year. When
forty-nine interviews were actually performed in these five codes, the
total quantity picked up, now based on the secure Kpye figures, was
11,551 million pounds per year. This indicated that, for the group of
five codess the estimated figure was within 19% of the secure figure and
that the twenty-four code total would have been off by only about 1%
if the forty-nine interviews had not been performed. This experimental
demonstration provides some justification of the validity of the estimates
used for previously non-projected codes. Incidentally, specifically
excluded from the project scope is the petroleum industry solid waste
and this industry will not be included in the non-projected codes.
Except in Code 20 the scrap and waste Kpye was the one assigned,
together with a disposition - disposal pattern for scrap and waste. In
general, these assignments were taken to be the same as for some other
projected code based on similarities. For example, it was judged that
Code 19, Ordinance and Accessories, would be similar to codes 35 plus 34
(ex. 3411) and to Auto and Aircraft, Code 37, which had respectively
scrap and waste of 6.0 and 4.25 Kpye, and disposition - disposal patterns
quite similar such that the utilization fraction was about 50%, leavinp
respectively 2.93 and 2.14 Kpye as waste for disposal. Accordingly,
for Ordinance, Code 19, there was used 6.0 for scrap and waste and 2.93
for waste for disposal. The Kpye values for several codes were assigned
on the basis of the A mean figure for plant trash and shipping wastes
from Section VI. These were stone and clay (ex. glass) based on the A.
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mean figure for plant trash and shipping waste, and primary metals
based on the X mean figure for plant trash plus one half the X mean
figure for shipping waste.
For foods (ex. meats) Code 20, the only non-projected codes were those
for which previous proprietary information was already available, so
the assigned Kpye's were derived from this information.
The growth factors used to project to 1975 were those available for the
2-digit codes previously used or available from the same source where
not previously used.
B. RESULTS,,- NON-PROJECTED AND PROJECTED PLUS NON-PROJECTED CODES
The results for the non-jprojected codes have already been shown in the
summary chapter Table I- and will not be represented here. The non-
projected codes added 47,686 million pounds per year to the 1965
projection and approximately 5,900,000 to the employees covered. The
total employees covered in projected and non-projected codes thus
becomes approximately 16,048,000 in manufacturing codes.
The Kpye corresponding to these totals for the non-projected codes is
8.1. Since there is very little lumber industry (Code 24) waste in this
total, the Kpye should be compared with that for the manufacturing codes
(ex. saw mills) among the projected codes, where the Kpye is 5.56. This
comparison highlights a basic reservation on the non-projected codes
which the reader should keep well in mind in using these results.
The Kpye assignments to the non-projected codes are for the most part
not based on actual information but on an assignment of similarities
between non-projected codes and corresponding or related projected codes.
The selected codes were selected because there existed prior information
that they had relatively high Kpye's. Some of the non-selected codes
were known to have low Kpye's but about the remainder there was simply
a lack of information. Secondly, the true Kpye for the non-projected
codes may indeed be less than the assigned values, for in the assignment
a conservative viewpoint was taken of associating each non-projected
code with a similar projected code, rather than making an outright
guess on the Kpye of the non-projected code. The conclusion is that if
the million pound per year total for the non-projected codes is in
error, it is more likely to be higher than the true value rather than
lower than the true value.
In addition to the foregoing uncertainties, there is one non-projected
code which has a particular uncertainty which should be mentioned. Prior
information on veneer and plywood plants indicated that the waste for
disposal was zero because all waste was used as fuel. Considering the
quantity of wood handled by the veneer and plywood industry, and the
basis in only four interviews, this assignment of zero Kpye must be
considered tentative,, and one of the priority items in firming up the
non-projected codes in future work should be to explore the veneer and
plywood industry.
-124-
-------
Accepting the reservation with respect to the non-projected codes,^
the total mpy in manufacturing codes projected plus non-projected is
168,468, or excluding saw mills, 102,868. For all codes covered,
manufacturing and non-manufacturing and projected and non-projected,
the total mpy is 229,229 or excluding saw mills, 163,629.
The non-projected codes in manufacturing contribute about 28% of the
total manufacturing waste for disposal and about 21% of the manufacturing
and non-manufacturing codes covered in the study.
The 1975 mpy for the non-projected codes is expected to increase in
accordance with the growth factors for the 2-digit codes previously
used. It will be remembered that in the 1975 predictions for the pro-
jected codes it was taken that the waste for disposal from the
Western saw mills would become zero by 1975. If this does indeed occur,
the waste for disposal for all manufacturing codes, projected plus
non-projected, will remain about the same over the period, approximately
168,000 million pounds per year. The waste from manufacturing (except
saw mills) will increase by about 40% reflecting the overall physical
growth factor. That from all codes, manufacturing and non-manufacturing
and projected and non-projected, is predicted to increase by about 5%
reflecting the increase in the manufacturing (except saw mills) codes
and the decrease in the Western mills.
C. DISPOSITION - DISPOSAL PATTERNS, PROJECTED PLUS NON-PROJECTED CODES
This chapter has explained that the waste quantities from the non-
projected codes are estimates with a lower order of confidence than the
projected codes quantities, and the disposition - disposal, Chapter VII
has explained that the disposition - disposal pattern is less secure
than the waste quantities, for reasons explained therein. This section
is about to compound these insecurities by assigning disposition -
disposal patterns to non-projected codes and applying these against the
non-projected code quantities. With absolutely no information avail-
able, the only assignment pattern that could be made was the assignment
of the same pattern as some corresponding industry among the projected
codes, usually the very one from which the Kpye assignment was made.
As has been previously maintained, the disposition - disposal pattern
of an industry is probably not dependent upon the S.I.C. Code, but more
likely to be dependent upon the particular physical environment of the
industry. Since most of the establishments in the non-projected codes
exit in urban centers, the pattern is that characteristic of the national
pattern for urban centers.
When these assignments are made and the computations are made as described
in Section VII, a set of disposition - disposal distributions corresponding
to those presented in Tables XII, XIII and XTV of Chapter VII results.
The presentation of such distributions for the non-projected codes
alone is not made here. The distribution quantities for the projected
plus the non-projected codes are shown in Tables XVI, XVII and XVIII.
-125-
-------
TABLE XVi
DISTRIBUTION OF WASTE FOR DISPOSAL AMONG
VARIOUS DISPOSITION - DISPOSAL MODES
Projected Plus Non--Projected Codes
Manufacturing Plus Non-Manufacturing
DISPOSITION AGENT
A11 Co^gp ^n
million/lb/yr percent Ili-A-
Self (at site) 110,121 47.C 44,637 21 2
Self Remote 54,108 23.5 54,108 32.9
Contract 56,678 24.6 56,678 34.5
Municipal 8,243 3.6 8,243 5.0
Unknown 1,247 .5
Total 230,397 100.0 164,335 100.0
TYPJE _0_F_JJL_T_IMATE DISPOSAL OR REDUCTION
Incinerator or Burner 89,888 39.0 35,960 21.9
Dump 94,307 40.9 84,677 51.5
Sanitary Land Fill 23,471 10.2 23,471 14.3
Open Burning 5,921 2.6 3,995 2.4
Fill 428 .2 428 .3
Unknown 16,382 7.1 _lJLx§OA _JL!
Total 230,397 TOO.O 164,335 100.0
OWNERSHIP OF ULTIMATE DISPOSAL OR REDUCTION FACILITIES
Self 110,836 48.1 45,352 27.6
Municipal 79,923 34.7 79,923 48.6
Contractor or Merchant 20,546 8.9 20,546 12.5
Unknown 19,092 _8JU3 18,514 _11^3_
Total 230,397 100.0 164,335 100.0
-126-
-------
TABLE XVII
Projected Plus Non-Projected Codes
Manufacturing Plus Non-Manufacturing
All Codes
d-llion/lb/yr percent
All Codes Except Saw Mills
million/lb/^T percent
Incinerator or burner
Dump
Sanitary Land Fill
Open Burn
Fill
Unknown
Total
84,853
19,133
932
5,490
428
0
110,836
76.6
17.3
4,9
.4
0
100". 0
30,925
9,503
932
3,564
428
0.
45,352
68.
20,
2.1
7
100.0
TABLE XVIII
DISTRIBUTION BY OWNERSHIP OF DISPOSAL FACILITIES
OF INDUSTRIAL WASTE HAVING CONTRACT DISPOSITION
All Codes
million/lb/yr percent
All_Codes_ Except Saw; Mil_ls
percent_
Self
Municipal
Contractor or Merchant
Unknown
Total
715
26,338
13,303
16,322
56,678
1,2
46.5
23.5
28.8
100.0
715
26,338
13,303
16,322
56,6^8
46,5
23.5
_28_._8
100.0
-127-
-------
While the waste quantities are different due to the addition of the
non-projected codes, the percentage in these Tables does not differ
greatly from those in the corresponding Tables XE ,XDI and £V, Section VII,
and the discussion of the results in Section VII is applicable to the
total of the projected and non-projected codes in the Tables just shown.
The only slight change that would be made is that of the industrial
waste collected by contractors (distributing the unknown in the same
manner as the known) about two-thirds goes to a municipal owned facility
and one-third to a contractor merchant owned facility.
When it is recalled that the disposition - disposal patterns for the
non-projected codes were taken individually as the same as that for some
projected code, it might be questioned why the percentages (except
saw mills which do not occur in the non-projected codes) should change
at all. The reason is that the proportions of the individual non-
projected codes waste are of course not the same among the non-projected
codes as the companion projected codes are among the projected codes.
-128-
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SECTION IX
WASTE FOR DISPOSAL BY STATE
The same general methods used to project waste for disposal for the
United States can be used, with some modifications, to project waste for
disposal for each of the fifty states and the District of Columbia. In
this projection it was assumed that the disposition and disposal pattern
for each state was the same as that for the nation. This, of course, is
not correct, but must remain as one of the approximations in the 51 state
projections because to develop disposition - disposal patterns for each
state would require 51 times as much information as for the national.
Growth factors for the individual states also were not available and,
therefore, projections were not made for 1975.
In general, with the exceptions noted immediately below, the Kpye's for
waste for disposal were taken from the last column in Table I of Chapter II.
These were multiplied by the number of employees in each code, developed as
described below, to obtain the million pounds per year of waste for disposal
for each code and each state. The code totals for each state were then
summed to produce the totals for each state. The general Kpye method was
also used for meat packing, Code 201, even though the U. S. total was
developed by a non-Kpye route. Doing so requires the assumption that the
ratio of meat packing establishments with slaughter to meat packing
establishments without slaughter is the same in each state as it is in the
nation. The exceptions to this procedure are detailed in the following.
For cotton gins, the original data has been developed via the state-by-
state method using data on bales ginned.
The method of projecting demolition utilized a state per capita figure.
This per capita amount was multiplied by the SMSA population in each state.
The saw mill projection was made on a pounds per board foot basis, dis-
tinguishing between Eastern mills and Western mills. These factors were
applied to the board feet of lumber production for each state using the
data from the 1963 "Census of Manufacturers". For example, in that listing,
North Dakota, Nebraska and Kansas are grouped in board feet production.
The group total was1 assigned to each of the three states in proportion to
the number of establishments in each state.
For stockyards, the terminal yards contained in the sample itself are
assigned to their respective states. The terminal yards not in the sample
were computed via the cattle equivalents and assigned to their states. No
information is available on the number of auction yards in each state.
Accordingly, the U. S. total for auction yards was apportioned among the
states in proportion to the number of cattle (not cattle equivalents)
slaughtered. In the available information, the New England states are
grouped. The million pounds per year for the group was apportioned among the
individual New England states in proportion to the cattle on farms
January 1, 1965.
-------
For super markets, the "County Business Patterns" data gives the number of
reporting units with more than 19 employees in each state, but not the number
of employees. The U. S. 1963 "Census of Business" had employees in
establishments greater than 19 employees in the nation, but not by state.
For the United States, there was obtained the average number of employees
per reporting unit in reporting units above 19 employees and this average
was applied to the number of reporting units in each state above 19
employees. The overall method used (see beyond) brought about the result
that the U. S. total super market waste is distributed among the states in
proportion to their population of employees in reporting units with more
than 19 employees rather than of employees in eg; tablishments with more than
19 employees.
A. OMISSIONS FOR DISCLOSURE
In the U. S. projections it has been possible to obtain a census
figure for the number of employees in each 4-digit code used. This
was not so in the individual states because there were a number of
omissions for disclosure. These are cases where numbers are deleted
from the tables in order to avoid disclosure of information on
individual establishments. It is of course more likely to occur where
the total number of establishments is small as in the states. The
"County Business Patterns" gives information on the number of estab-
lishments in each of several employee size classes without any omis-
sions. It is common practice to multiply the number of establishments
in each employee class by some number lying within the class which
represents the average employees per establishment in that class. The
sum of these products will be an estimate of the total number of
employees in all classes. This amounts to an integration of number of
establishments against average employees per establishment over all
size classes. A customary approximation is that the average number of
employees per establishment in a class is given by the mid-point of the
class boundaries. However, this in general is true only if the
distribution of establishments by number of employees is uniform. The
true distribution of establishments by number of employees approximates
log-normal and, therefore, the average in each class is in general not
at the mid-point of the class.
Consider the following definitions and relationships:
Integration Point ic = nc
ec
where:
nc = employees in class
ec = establishments in class
ic = integration point for that class, employees per
establishment
-130-
-------
then:
where:
N = total employees in all (8 census) classes
Now define a term rc, integration point factor, such that
nc = [Lc + rc (Uc - LC7) ec
or
ic = Lc + rc (Uc - Lc)
where:
LC = lower class boundary, number of employees
Uc = upper class boundary, number of employees
This integration point factor is the fraction of the interboundary
distance ab-ove the lower class boundary at which lies the integration
point. In customary practice, the integration point factor is taken at
0.5, i.e. the integration point is the mid-point of class.
Now: 8
N " / [Lc + rc
-------
overall integration point factors for the 2-digit codes were computed
(from the 1964 distributions and totals). It was assumed that the
overall integration ooint factor for the U. S. 2-digit codes was
applicable to the 4-digit state distributions and the number of employees
for the omitted 4-digit codes in each state was computed by applying
the national 2-digit overall integration factors.
However, a complication arose in this because of the scheduling of data
availability. When this task was begun, the 1965 distributions were
available but the 1965 U. S. summary employee totals had not yet
become available. Accordingly, the 1964 integration point factors were
applied against the 1965 distribution data with the idea of thus
approximating the 1965 totals. There was nothing against which to check
the 4-digit totals so computed since the 1965 summary data were not
available. However, when the 1965 projections of the 4-digit codes for
each state were summed over all 51 states, these totals were in many
cases quite deviant from the corresponding (and available) 1964
employee totals. Rather than awaiting the publication of the 1965
summary data which would allow the whole process to be repeated on the
complete 1965 data, an adjustment was made to bring the individual
4-digit state totals, as above computed, back to values which when
summed over the 51 states would produce the correct 1964 total. This
was done by applying to each state a single correction factor which was
the correct 1964 employee total divided by the incorrect sum previously
arrived at. The result is that the individual state figures in these
omitted 4-digit codes represent the 1964 totals computed as if the 1965
distribution applied.
Another complication modifying the above general procedure involved
the establishments with greater than 500 employees which constitute an
upper open-end class. This was treated separately, which means that the
summations previously described for eight classes, the general case,
were actually computed over only seven classes, and to the seven-class
total was added the special greater than 500 class now to be described.
There is available for each 2-digit code the number of employees in
establishments greater than 500 and the number of such establishments.
These two produce an average employee per establishment in establishments
greater than 500 in each code, for the U. S. applied also to the
individual states and to the 4-digit codes and the number of employees
in the greater than 500 establishments was computed in this way.
The figures for the non-projected codes for each state were produced
as described in Section VIII and the employees for the codes having
omissions for disclosure were produced as just perviously described,
except that for a few 2-digit codes the computation was shortened by
taking an overall integration point factor of 0.37 instead of computing
an ingegration point factor for these few codes so treated.
B. RESULTS
The 51 state data are shown in Table XIX. The second through fifth
columns show the state totals for the projected codes in the four
categories previously used.
-132-
-------
TABLE XIX
Projected
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of Columbia
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
Sputh Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
U. S. Total
Manufacturing
Codes
3,882
124
572
4,456
9,938
478
981
289
95
1,906
4,718
111
2,025
4,250
2,198
869
.437
1,802
3,234
1,223
1,421
2,454
3,684
1,426
2,923
1,974
1,462
301
54
624
2,278
309
5,350
5,728
34
5,162
699
9,858
5,587
305
2,687
200
3,306
3,908
198
515
4,592
5,041
1,814
2,738
146
120,366
Manufacturing
Codes
Except Saw Mills
821
12
145
600
3,873
231
918
221
95
1,128
1,472
111
128
3,898
1,800
727
389
668
772
454
967
2,244
2,633
977
540
1,207
40.
287
14
280
2,198
39
4,493
1,880
25
4,358
378
398
4,053
305
819
58
1,613
1,792
190
174
1,230
683
556
2,011
11
54,916
All Codes
4,361
142
847
4,717
13,754
834
2,970
523
922
3,264
5,269
190
2,111
8,333
3,327
1,356
861
2,411
3,750
1,435
2,775
6,331
6,591
1,974
3,171
2,799
1,533
525
126
766
5,687
432
16,230
6,545
86
8,736
1,105
10,082
10,910
986
3,047
279
4,215
6,494
354
554
5,546
5,516
2,040
3,738
182
180,732
All Codes
Except Saw Mills
1,300
30
421
860
7,690
588
2,907
455
922
' 2,486
,2,023
190
214
7,981
2,930
1,214
813
1,278
1,288
665
2,321
6,121
5,541
1,525
788
2,002
112
511
86
423
5,607
162
15,372
2,697
77
7,932
784
622
9,377
986
1,178
137
2,523
4,378
265
293
2,183
1,157
782
3,011
47
115,255
WASTE FOR DISPOSAL BY STATE
Non-Projected
Non-Projected
Manufacturing
Codes
532
27
136
536
3,503
274
986
130
188
901
656
80
76
3,794
1,443
493
243
589
325
1,001
674
2,401
2,136
649
710
1,572
58
225
40
234
2,205
59
6,347
1,026
31
2,736
232
370
3,698
335
367
40
1,192
1,394
117
114
803
491
267
1,264
29
Manufacturing
Codes
4,415
151
708
4,993
13,441
752
1,967
419
283
2,808
5,375
191
2,102
8,044
3,641
1,362
680
2,391
3,559
2,225
2,096
4,856
5,821
2,075
3,633
3,543
1,520
526
95
859
4,483
368
11,697
6,754
65
7,899
931
10,228
9,285
640
3,055
240
4,499
5,302
315
630
5,396
5,532
2,081
4,002
176
Prelected and Non-Projected
47,729
168,109
Manufacturing
Codes
Except Saw Mills
1,353
40
282
1,136
7,376
. 505
1,904
351
283
2,030
2,129
191
205
7,692
3,2^44
1,220
632
1,258
1,097
1,455
1,641
4,645
4,770
1,626
1,251
2,779
98
512
55
515
4,404
98
10,840
2,906
57
7,095
610
769
7,751
640
1,186
98
2,806
3,186
307
289
2,033
1,174
823 '
3,275
40
102,661
All Codes
4,894
169
984
5,253
17,257
1,109
3,956
653
1,110
4,166
5,926
270
2,188
12,127
4,771
1,849
1,104
3,000
4,075
2,436
3,450
8,733
8,728
2,623
3,882
4,371
1,591
750
166
1,001
7,892
491
22,577
7,571
118
11,472
1,337
10,452
14,609
1,321
3,414
320
5,408
7,889
471
668
6,349
6,007
2,308
5,003
212
228,481
All Codes
Except Saw Mills
1,332
58
558
1,397
11,193
862
3,893
585
1,110
3,388
2,680
270
290
11,775
4,373
1,707
1,056
1,867
1,613
1,667
2,995
8,522
7,674
2,174
1,499
3,574
170
736
126
657
7,813
221
21,719
3,723
109
10,669
1,016
992
13,075
1,321
1,545
178
3,716
5,773
382
328
2,987
1,648
1,050
.4,276
76
162,918
All Codes
Per Capita of
Total Population
Kpyc
1.404
.635
.625
2.706
.938
.569
1.398
1.298
1.385
.719
1.350
.380
3.157
1.140
.975
.670
.490
.945
1.145
2.471
.976
,629
.049
,736
.681
.973
2.263
.514
.382
1.487
1.164
.485
1.247
1.534
.181
.120
.546
.393
,261
1.482
1.339
.467
1.404
.745
.474
Kpye
Manufacturing
Except Saw Mills
5.71
10.6
5.1
11.3
5.8
6.0
4.7
8.7
13.2
9.0
6.1
8.3
6.9
"6.8
5.5
7.0
5.6
7.3
9.0
15.4
6.6
7.4
5.1
7.4
10.2
7.4
7.1
8.5
8.1
6.4
5.9
7.3
6.5
5.7
9.6
6.1
7.4
7.0
5.9
5.9
4.6
8.2
8.7
6.7
656
436
021
.272
.208
.643
1.182
6.4
9.5
7.1
6.3
7.5
7.4
10.1
6.5
-133-
-------
Among the projected codes the states with the highest waste for disposal
for all manufacturing are those which are heavy in saw mills, California
with 9,990 million pounds per year and Oregon with 95860. When the
saw mill waste is eliminated, the high states are, of course, those
which are high in manufacturing other than saw mills, New York with
4,500, Ohio and Pennsylvania with 4,050, California with 3,930, and
Illinois with 3,880. Among the four non-manufacturing codes, the largest
contributors are demolition and super markets which to some extent
follow the population, but the per capita demolition in California is
quite low. Accordingly, for all projected codes (except saw mills)
New York is the highest with 15,380 million pounds per year followed by
Pennsylvania with 9,370, California with 7,740, Illinois with 7,970
and Ohio with 7,620.
The sixth column shows the waste for disposal from the non-projected
codes and the next four columns show the corresponding totals in the
four categories for projected plus non-projected codes. For manu-
facturing (except saw mills), when projected plus non-projected codes
are included, the top five .states are still the same as for the pro-
jected codes, but in slightly different ranking; New York with 10,840
million pounds per year, Pennsylvania with 7,750, Illinois with 7,690,
California with 7,380 and Ohio with 7,100.
When the four non-manufacturing codes are included, the ranking is the
same.
New York 21,720 million pounds per year
Pennsylvania 13,080 million pounds per year
Illinois 11,780 million pounds per year
California 11,200 million pounds per year
Ohio 10,670 million pounds per year
Overall, codes covered in the study, manufacturing and non-manufacturing,
projected and non-projected, the two states heavy in saw mills enter
into the top six.
New York 22,580 million pounds per year
California 17,260 million pounds per year
Pennsylvania 14,610 million pounds per year
Illinois 12,130 million pounds per year
Ohio 11,470 million pounds per year
Oregon 10,450 million pounds per year
The last column shows the manufacturing plus non-manufacturing code,
wastes in ratio to the total resident population (P) both urban and
rural, in units of Kpyc, kilo pounds per year per capita. This is
more easily discussed by reference to Figure 6 which illustrates the
intensity of waste for disposal generation in units from which the
effect of high total populations has been eliminated. The states with
the highest per capita intensity of waste for disposal are those in
which the saw mill industry is prominent and the overall population is
relatively low, these being Oregon, Idaho, Arkansas, Maine, Montana and
-134-
-------
u>
vn
1965 PER
CAPITA WASTE FOR DISPOSAL, BY STATE
2.02
2.26
5.39
3.16
.64
.38
.47
.57
.94
.68
.49
Figures are KPYC thousand pounds per year per capita
U. S. Average: 1.18
2.47
1.65-
18
.74
1.49
-1.63
.47
1.05
1.25
1.05
.67
.51
1.12
1.14
.98
1.27
.49 .97
.95
1.26
1.44
1.53
.55
2.71
1.68
.75
1.15
1.40
1.40
1.34
1.35
.72
-1.48
-1.40
-1.16
-1.30
-.98
-1.39
Figure
-------
Washington, in that rank order, The per capita intensity of waste
generation in Oregon is 4.6 times the national average of 1.18 Kpye.
This national average figure of 1.18 Kpyc signifies that the per capita
waste generation in the codes covereo for the nation is 1,180 pounds
per year, or 3.23 pounds per calendar day.
States in the next mapped category of 1.5 to less than 2 Kpyc are those
in which lumbering or woodworking are prominent, or manufacturing is
intense, or both. This category includes Mississippi, North Carolina
in the first class, Massachusetts in the second, and Vermont probably
in the third.
The next mapped class from 1 to 1.5 Kpyc includes most of the remaining
states east of the Mississippi except Indiana, Kentucky and Florida.
These last find themselves in the next lower mapped class which is
typical in the middle tier of states.
Finally in the lowest class of 0 to 0.5 Kpyc are the few remaining
Western states which are heavy neither in lumbering nor in manufacturing
The reader is reminded that the codes covered in Figure 6 are all
manufacturing codes, except 29, Petroleum Refining, for which there is
included only a small 4-digit code, 2952, Asphalt Roofing, plus the
four non-manufacturing codes studied, Cotton Gins, Demolition, Stock-
yards, and Super Markets with twenty or more employees. From the data
presented in the tables, the reader may construct for himself other
per capita maps showing manufacturing alone, manufacturing except saw
mills, etc.
C. EFFECT OF S.I.C. CODE PROFILES
The state-by-state data provide an opportunity to test a question which
has been lurking beneath the surface of the present study. The concept
of the study is that the A mean Kpye's for different codes will not be
the same and, therefore, the total Kpy is obtained by summing the
products of the Kpye for each code times the number of employees in
that code.
Consider a quantitative description of an economic region, nation,
state, county, or otherwise which may be termed the "S.I.C. code pro-
file". Consider that the fraction code employees divided by total
employees is plotted for each code in the form of a bar graph arranged
according to increasing S.I.C. code number, taken here as 2-digit
codes. Then the outline of this bar graph will be the S.I.C. code
profile and will be a characteristic of the region considered. Taking
only the manufacturing codes it may be visualized that the S..-I.C. code
profile for Washington and Oregon will be high at code 24 representing
the lumber industry, whereas in other states not heavy in lumbering,
for example Kansas and Nevada, the level of the profile at code 24 will
be low compared to the remainder of the codes.
Now for each bar on these profiles there is associated a Kpye value
corresponding to the code, and in this study taken as the same in all
states for a given code.
-136-
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Consider the following relations:
P = total employees in state
p.j_ = fraction of total employees in code i
K-^ = Kpye for code i
Then:
Z. P^PK^ _ £py waste in state
i
^~ P-j-P = employees in state
i
^ PiPKi
^ = overall Kpye for state = L
i Pip
But:
~ ^ = 1.0
i
. . = overall Kpye for state =
If the S.I.C. code profiles for each state were identical then the
overall Kpye for each state would be the same, and therefore, one could
estimate the Kpy of waste for disposal by using this overall Kpye
multiplied by the number of employees in each state, without going
through the code-by-code breakdown.
It is clear from the actual numbers that if saw mills are included,
one cannot hope for a common Kpye over all 50 states since several of
the states are heavy in saw mills and saw mills, having a very high
Kpye, these states certainly would have a high overall Kpye. Thus, the
meaningful question about to be proposed, and answered, applies to the
entity/manufacturing codes, except saw mills, 242. The question is:
"Are there enough differences among S.I.C. code profiles for manu-
facturing, except saw mills, from state to state to make it necessary
to proceed with estimates via the code-by-code process, or do the
S.I.C. code profiles differ from each other by an amount small enough
to allow the successful application of such an approximation?"
This question can be answered. The overall Kpye's for the 51 states
for manufacturing, except saw mills, are shown in the last column of
Table XIX. The answer is "Yes", there is a considerable range in the
-137-
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Kpye's presented from 4.6 to 15.4. These numbers are log-normally
distributed with a median of 7.4 Kpye and a a ratio of 1.30. About
35 percent of the states have Kpye's less than the national average
of 6.50, but these states are not clustered in any particular
geographical region.
Therefore, the conclusion is that there are enough differences in
S.I.C. code profiles from state to state to make necessary the use of
the S.I.C. code route in projecting state waste for disposal
-138-
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SECTION X
WASTE FOR DISPOSAL BY COUNTY IN CONNECTICUT
The methods used to project waste for disposal for the individual states
can be used, with still further modifications and approximations, to pro-
ject the waste in individual counties. The state of Connecticut, comprising
eight counties was selected for study because there was available a studyl^
which attempted to project economic production to future years. The
objective of the present chapter is a projection of the waste for disposal
by Connecticut counties and the projection of these to 1975. The method
used assumes that the disposition - disposal pattern for each county is
the same as that for the nation. This assumption, of course, becomes less
tenable as the size of the region being projected is decreased. The pro-
jected and non-projected codes were not handled separately, but were
combined by generating a combined Kpye from Table I in the summary, Section
II. The 4-digit sub-codes, having Kpye's differing from the residual sub-
codes in any 2-digit code were treated separately, however. The resulting
Kpye assignments are shown in Table XX.
The reader is reminded that these assigned Kpye values represent A mean
Kpye's developed from individual establishment Kpye's which have a scatter.
By the general method used, the A mean Kpye is that which will give the
correct total when applied against each establishment in a large number of
establishments such as a national population of"establishments in a code.
The mathematical mechanism, which makes this possible, requires not only
that the population of establishments will rather closely approximate log
normal, but also that the distribution will extend to percentile levels
encompassing the entire population, i.e. to the 99th percentile if there
are 100 in the population, to the 99.9 percentile if there are 1,000 in
the population, etc. It has also been shown for the establishments actually
interviewed, even though their number may be quite small (6 to 30 establish-
ments), that the distribution for this interviewed sample is not too far
from log normal. It only extends, of course, to a percentile corresponding
to the sample size, e.g. to the 86th percentile for a sample of 6. The
A mean Kpye for a population of about the same size as such a sample would be
lower than the A mean Kpye assigned for populations of 1,000 or so which
are common population sizes in the states and the nation. Thus, if one had
100 samples of 6 establishments each, for most of these 100 samples, the
total Kpy would be less than that computed by application of the assigned
Kpye. For a few of these 100 samples, the actual total would be much greater
than that obtained from the assigned Kpye, and to such an extent that the
total Kpy (for the 600 establishments taken together) would be found to bP
correct.
Now recognize that in the Connecticut counties one is dealing with code
groups which may contain quite small numbers of establishments The
elusion is, with the reservation stated in the next paragraph 'that nnol- f
these will tend to be over-estimated in Kpy. agraph, that most of
-139-
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TABLE XX
KPYE ASSIGNMENTS
PROJECTED PLUS NON-PROJECTED CODES
FOR CONNECTICUT STUDY
Code
19
20
2011, 2013
2015
2043, 2044
2051
2095, 2061
21
22
23
242
2431
2433, 249
244
25
2514, 15, 22, 59
26
27
28
281
285
295 less 2951
30
31
32
322, 323
33
34
3411
35
36
37
38
39
0712
0719
1795
541
Description
Ordinance
Residual Foods
Meats
Poultry
(None in Connecticut)
Bakeries
(None in Connecticut)
Tobacco
Textiles
Apparel
Saw Mills, General
Mill Work
Fre-fab and n.e.c.
Containers
Wooden Furniture
Metal Furniture
Paper
Printing and Publishing
Residual Chemicals
Basic Chemicals
Paints
Asphalt Roofing
Rubber and Plastic
Leather
Stone, Clay, (Residual Glass-32)
Glass
Primary Metals
Fabricated Metals
(None in Connecticut)
Machinery
Machinery, Electrical
Transportation Equipment
Instruments
Miscellaneous Manufacturing
(No Cotton Gins in Connecticut)
Auction Stock Yards
Demolition
Super Markets >19
5.96
10.8
2.52
0.562
277
8.65
87
85
11.5
7.13
17.5
16.5
12.6
0.47
5.3
80.5
11.9
19.5
5.01
04
93
93
08
2.14
5.36
4.59
None
By Total Population
35.7
-140-
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However, completely over-riding this general tendency, which would be true
if one were dealing with 100 counties, since we are dealing with only
eight countiess it is quite possible that the relatively small numbers of
actual establishments existing in one of these counties may find themselves
to be from the high part of the Kpye distribution curve, or from the low
part. This will be true with a certain number of samples, even out of 100
samples, but we do not have the information to determine whether it may
have occurred in one or more of the eight counties being studied. To
place this reservation in terms of a more faimilar concept, applying the Kpye
statistical method, to entities as small as counties, is like utilizing
the actuarial method of estimating how many people will die in a given year
out of the total population, to predict whether certain particular persons
will die. This study does not attempt to quantify the probability that
this has happened. It simply points out this defect as a reservation.
For most codess the mpy's were generated via the Kpye figure, but because
of the small size of the regions considered, there were many more omissions
for disclosure to be filled in by the method previously described. In the
application of this method the single overall integration point factor of
1.37 was used rather than using those characteristic of the 2-digit codes.
The employee data used was from the 1965 "County Business Patterns". *-'
Certain codes received special handling as follows. For demolition the
figure of 1,579 million pounds per year found for Connecticut in the 51
state study was apportioned among the eight counties according to total
population per county. Urban population per county might have been a better
base, although probably differing not by much from total population, but
the best available basis for projection to 1975 was by total population and
therefore, total population was used.
In the U. S. and 51 state studies, saw mills was projected using production
in board feet, but since there are only 161 employees in Connecticut in
Code 242, the projection was based on the Kpye from Table I.
Super markets were handled in the same way as described for the 51 state
study, with the reservations applicable as noted. However, the method was to
apportion the 409.5 million pounds per year waste for disposal for
Connecticut super markets from the state-by-state study among the eight
counties by the employee proportions.
There are no terminal stockyards in Connecticut and this study did not
determine whether there are any auction markets. Auction markets occur in
Code 0719 and the state has only four reporting units in the 3-digit
Code 071. Two of these are in the 20 to 49 and the 250 to 499 employment
size classes and, therefore, not likely to be auction markets. The 51
state study assigned 0.6 million pounds per year to stockyard wastes for
Connecticut and since this is so small, it will be considered zero in the
Connecticut county-by-county study.
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A. PROJECTION TO 1975
In view of the paucity of basic data available, the projection of waste
quantity by county to 1975 requires considerable manipulation. Physical
production growth factors were not available for Connecticut counties
and, therefore, the only recourse was to use employee projections
which were available. Elsewhere in this study it was assumed that
waste/product ratios will change with time much less than waste/employee
ratios because of the expected changes in productivity. The procedure
used here involves a ficticious constancy of productivity over the
prediction period. This is known to be incorrect, but on the other
hand, the changes in productivity between different counties in the same
codes will probably not be great and by that device the relative changes
in county waste for disposal will be the result of the prediction.
This also contains an approximation, however, in that productivity
changes will probably be different for different codes and therefore,
the overall productivity change in a county will be a function of its
S.I.C. Code profile, which presumably is different from county to
county among the eight counties. This can not be dealt with using
available data.
To outline, there are data available which can produce for the entire
state and for each manufacturing code the difference in employment
between 1965 and 1975. Also, there are available data which can produce
the difference between 1965 and 1975 employment for all manufacturing
codes in each county. The sum of these differences is 89,151 employees.
The method provides figures such that the total of all manufacturing
codes for each county will equal the increase for each county, and the
total of all counties in each manufacturing code will equal the difference
in that manufacturing code. Stated in other words, the participation
of each manufacturing .code in a county is proportional to the participation
of that code in the entire state; and the participation of each county
within a manufacturing code is proportional to the participation of
that county (for all codes) within the state. In contrast to this
assumption of uniformity, a large percentage of the state's growth in
a particular code, might be in some single county and that county might
indeed be one of those whose total growth in all codes has been
relatively small compared to the others. However, there is absolutely
no way to obtain these individual characteristics from the available
data and the present method has the virtue of giving the correct totals
by county and by code.
The generation of the 1965 to 1975 employment differences by 2-digit
code (some of them grouped) comes relatively simply from the difference
between the 1975 figures and the 1965 figures.1^
The method used computed the participation of Fairfield County, for
example, in the state's total 1965 to 1975 increase in industrial
waste. Thus, by the assumptions of the method, it will have 7.827 percent
of the state's increase in each 2-digit code.
-142-
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In this way, the employee change, 1965 to 1975, is computed for each
county and each code or code group; some of the changes being negative.
The employee change multiplied by the corresponding Kpye produces the
waste quantity change over 1965, which when added to that figure from
the 1965 computation produces the 1975 prediction.
For the increase 1965 to 1975, it was necessary to regroup some of the
Kpye's because of the grouping of the basic data. This was done by
developing a group Kpye which is the overall Kpye for the codes grouped
for the entire state. Code groups so handled were 19+39, 21+29,
24+25. In addition, it was necessary to group some 4-digit codes to
correspond with the 2-digit codes of the 1975 prediction, these being
28 + 32.
It should be recognized that each time there is a regrouping of codes
and a computation of an overall Kpye for the group, there is involved
the fiction that the make-up of the grouped code in the sub-codes
grouped is the same in the entity to which it is to be applied as in
the entity from which the grouped Kpye figure was computed. In this
case, it means for example that the computations for the individual
counties for the grouped codes 19 + 39 are done on the premise that
the relative proportions of 19 + 39 employees in each county are the
same as in the state. If it should happen that the codes grouped have
identical Kpye's, then while the premise remains, the final result
will be correct. However, in most cases the grouped codes do not have
identical Kpye's.
For the 1965 to 1975 increase, the non-manufacturing codes received
special handling as follows. There are no cotton gins in Connecticut
in 1965 and the waste from whatever stockyard auction markets there
may be was taken as zero. It was assumed that there would be no change
to 1975.
For super markets, the increase was taken as proportional to the
estimated increase of total population in each county at a rate of
0.1455 Kpye (thousand pounds per year per capita) which corresponds to
the 1965 waste total of 409.5 million pounds per year.
For demolition, the 51 state study had computed a 1975 quantity of
1,894 million pounds per year for the state which with an estimated
1975 total population of 3,222,452 is 0.5878/1,000 million pounds per
year per capita of total population.
B. RESULTS
The results are presented in Table XXI.
In 1965 Hartford County makes the largest contribution with 1,047
million pounds per year followed closely by New Haven and Fairfield.
This ranking is maintained in 1975. The highest percentage growth in
the period, however, is for Tolland with 44 percent followed by
Middlesex with 40 percent. Fairfield and Windham Counties have the
smallest percentage growth.
-143-
-------
The next to the last column indicates the overall Kpye for the manu-
facturing codes, 1965. Note that this is different from the Kpyc
intensity figure discussed in the state-by-state portion of this
report, Section IX. The ratio presented in Table XXI is a Kpye, and
since Connecticut has very few saw mills, is most comparable with the
corresponding Kpye figure for manufacturing codes (except saw mills)
in Table I which has a national average of 6.50. The overall
Connecticut average for this figure is 4.65. Middlesex County has the
highest Kpye with 6.76 and Hartford County the lowest with 3.87-
-144-
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TABLE XXI
WASTE FOR DISPOSAL
CONNECTICUT (BY COUNTY)
1965 and 1976
Mf g . and
Counties
Fairfield
Hartford
Litchfield
Middlesex
New Haven
New London
Tolland
Windham
Mfg. Codes
1965
485
502
76
80
538
142
16
81
Non-Mfg.
Codes
1965
1,010
1,047
169
156
1,035
285
72
138
Mfg. Codes
1976
516
690
77
104
656
162
34
84
Mf g . and
Non-Mfg .
Codes
1976
1,098
1,342
189
218
1,271
354
103
153
Kpye
Mfg. Codes
1965
4.61
3.87
4.62
6.76
5.62
3.92
5.06
5.40
Percentage
Growth
1965-1967
All Codes
8.6
28.1
12.0
39.8
22.8
24.0
43.8
10.8
STATE TOTAL 1,920 3,912 2,321 4,728 4.65
-145-
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SECTION XI
REFERENCES
1. Plant and Product Directory. Fortune. 1966.
2. U. S. Bureau of the Census. County Business Patterns, 1964, U. S.
Summary CBP-64-1, USGPO, 1965.
3. Economic Index and Surveys, Inc. Predicasts. No. 24, Second Quarter
1966.
4. U. S. Department of Agriculture, Forest Service. Timber Trends in the
United^ States. Forest Resource Report No. 17, Feb. 1965.
5. Oregon State College. An Inventory of Saw Mill Waste in Oregon.
Engineering Experiment Station, Bulletin Series 17-
6. U. S. Forest Service, Forest Products Laboratory. Weights of Various
Woods Grown in the United States. Technical Note No. 218,
April 1961.
7. U. S. Department of Agriculture, Economic Research Service. Statistics
on Cotton and Related Data, 1925 to 1962. Statistical Bulletin
329 and Supplement for 1966 thereto, April 1963 and Nov. 1966, resp
8. U. S. Department of Agricultural Marketing Service, Cotton Division.
Cotton Gin Equipment. 1957, 1962, 1963, 1964.
9. U. S. Department of Agriculture, Economic Research Service, Marketing
and Economics Division and Agricultural Marketing Service, Cotton
Division. Charges for Ginning Cotton, Costs of Selected Services
Incident to Marketing, and Related Information.1962 to 1963,
ERS-2 (1963), May 1963.
10. U. S. Public Health Service, Bureau of Disease Prevention and Environ-
mental Control. Control and Disposal of Cotton Ginning Wastes.
A symposium, Dallas, Texas, May 3 and 4, 1966. Publication
No. 999-AP-31.
11. U. S. Department of Agriculture, Consumer and Marketing Service,
Packers and Stockyards Division. Packers and Stockyards Resume.
Volume III, No. 11, Nov. 26, 1965.
12. U. S. Department of Agriculture, Agricultural Marketing Service,
Statistical Reporting Service and Economic Research Service.
Supplement for 1963 to Statistical Bulletin No. 333. Livestock
and Meat Statistics, 1962. Aug. 1964.
13. U. S. Department of Agriculture. Suggestions for Improving Service at
Terminal Markets. ALT No. 36, Jan. 1952.
-146-
-------
14. Voorhees, A. M. and Associates, Inc. A Model for Allocating Economic
Activities into Sub-Areas in a State. Prepared for the
Connecticut Interregional Planning Program, 1966.
15. U. S. Bureau of the Census. County Business Patterns, 1965.
Connecticut CBP-65-8, GPO, Washington, 1966.
16. Aitchinson, J. and J. Brown. The Log Normal Distribution. Cambridge
University Press, 1963. "
-147-
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SECTION XII
APPENDIX A
INDUSTRIAL CHECK LIST
Establishment Data
Type of Establishment
Products
S.I.C. Code Classification
Other S.I.C. Codes Produced g
Plant Capacity
(product quantity, specify units)
Number of Employees total production
Seasonality (of production plant)
Operating Season ^._J.
Hours/Day
Days Per Week
Weeks Per Year
Changes in production pattern which would influence employee number
per unit output, waste production or disposal during next ten years?
(automation, process changes, product requirements, waste utilization
etc.)
Industrial solid wastes will be generated by the following sources and must
be researched individually (unless lumped together for disposal):
1. Office waste and general plant rubbish
(lunch containers, paper, etc.)
2. Shipping waste, in and out (pallets, boxes, containers)
3. Process wastes
4. Solid waste collected by air cleaning devices
5. Solid waste collected by liquid cleaning devices
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INDUSTRIAL CHECK LIST Pa8e 2
For each of the above waste streams, obtain:
Character
Description
% Moisture
Type of organic
Bulk density
Other
Present Disposition
A. Sold
How much of it
For what use
Price
F.O.B.
Quantity per day
Future
B. Municipal Disposal
Quantity per day
Collected by city
Hauled by self
How far
How many loads/day
Future
C. Contract Disposal
Quantity per day
How transported
-149-
-------
INDUSTRIAL CHECK LIST Page 3
C. Contract Disposal (cont.)
Ultimate disposal
(city or private dump or incinerator)
Future ______
D. Self Disposal
Method ______
If incinerator:
Make
Age
Size
Crew ________
Operating hours
Vehicle load _______
Cost (installed)
Satisfaction
Future
If open dumping, land fill or open burning:
Quantity
How far
Vehicle loads
Crew
Cost
Air Pollution
Requirements
-150-
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INDUSTRIAL CHECK LIST Pa§e 4
E. Future plans
Hypothetical incinerator practice
Hours/Day
Days/Week
Identify and obtain quantity, disposition and future disposition
of liquid wastes which are disposed of by means other than sewers
(i.e. incinerated, land fill, etc.)
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SECTION
APPEND ijyB
MATHEMATICAL HANDLING OF WAS_TE_QUANTITY_I)ATA
In the earlier proprietary, projects of Combustion Engineering, it had been
taken as a hypothesis that the waste/employee ratio in a particular
homogeneous group of industries would, show little dispersion,, This
hypothesis is based on the premise that, with a similar type of operation,
a single employee handles a certain amount of the physical material of the
industry corresponding to the productivity in that industry, expressed as
a product /employee or raw material/employee ratio. Furthermore, the f ract i -in
of waste generated in handling this material would be relatively cunstan'
within establishments in the industry and relatively independent of
establishment size, For example, the fraction of the raw material, wood
waste in manufacturing a chair would be the same from establishment to
establishment allowing some fluctuations for different degrees of ingenuity
in design and technique. The primary reasons for selecting waste/employee
ratio as a means of projection rather than waste/product ratio were two-fold.
First, it is easier to obtain employee size data for an establishment and
for groups of establishments than it is to obtain product size data.,
Secondly, a desired result in the earlier projects was a prediction of the
distribution of waste generating establishments by the amount of waste
generated. Data are available on the distribution of establishments by
employee size, which when applied against a waste/employee ratio, could
generate this distribution. This distribution by size is not of interest
in the present study, but the availability of number of employees data
is much greater than the availability of units of production data and the
original form therefore is preferable also for this study -
Probably a greater constancy can be expected for the ratio of waste/production
employees than for waste/total employees since it is largely the activities
of the production workers that generate the waste. However, date are not
available in the desired form on number of production employees whereas the
number of total employees is quite generally available,
As the number of data points in each industry code was built up through
successive studies, including the present study, it became evident that the
waste /employee ratio even for a technologically homogeneous group was not
constant from establishment to establishment but had a dispersion. A
technologically homogeneous group is one In which the establishments
carried out almost precisely the same operations on the raw material, so as
presumably to generate the same waste/product ratio. An example might be
saw mills, in which precisely the same operations are carried on from mill
to mill.
A technologically heterogeneous group is one in which the operations in the
establishments within the group are quite different and thus may be expected
to have different waste/product ratios. The food code, 20, is an example of
a heterogeneous groun including such things as rice milling, ice cream
-152-
-------
manufacture and pickle manufacture. The observed dispersion in waste/
employee ratios may arise from a number of component dispersions including
dispersions in productivity, dispersions in hours per year per employee,
dispersions in waste/product ratio attributable to differences in manufac-
turing techniques and efficiencies, to errors in estimates of waste stream
quantities, and to omission of certain components of the total waste stream
from establishment to establishment
While dispersion in productivity may contribute to the observed dispersion
in waste/employee ratio, it probably is not the sole dispersion entering,
because the dispersion in waste/employee ratio is considerably greater than
would be expected for a dispersion in productivity. An opportunity was
given to compare these dispersions in the wooden box industry and it was
shown that the dispersion in waste/employee ratio is substantially greater
than the dispersion in productivity.
Whatever the cause for the dispersion may be, it is an observed fact that
among the 24 codes studied, the sample distribution of waste/employee ratic,r
is log-normal in every code but one and one sub-code code of another. This
is not at all surprising, Indeed, based on extensive experience with
economic data of all types it would be quite surprising if these dispersions
were not log-normal. The log-normal distribution has been found to describe
a wide variety of social and economic statistics including costs of pipelines,
water treatment plants, dams, costs of water treatment, sanitary land fill,
pipelining of water, distribution of manufacturing establishments by employee
size, of cities by population size, of water systems by water production, and
many, many others.
Other workers have also found wide applicability for log-normal distribution,
citing income, bank deposits, distributions of wealth, distributions of
population, commodity prices and price changes, size or organisms, industrial
statistics, production throughputs, human measurement, and the distribution
of word frequencies. 16
The log-normal distribution is one in which not the numbers themselves but
the logs of the number are normally distributed. Such a distribution will
plot as a straight line on log-probability paper, on which there is plotted
the cumulative percentage of Incidences having parameter values greater than
(or less than) indicated on the log scale. With a small sample it is not to
be expected that the points will lie precisely on the log-normal straight
line since the sample is but a random selection of the universe or population
of data points. However, it has invariably been found that as the number
of points in the sample is increased, the broken curve passing through each
plotted point more closely approximates a straight line and extends as such
to higher and lower percentile values as extrapolated from the original
sample. Figure 7 gives examples of one of the best sample distributions and
one of the worst that were considered to be log-normal in this study. Also
shown is another set of 95 points expressing the dispersion of a different
set of economic data but included to show what happens when a sample size is
-153-
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THE LOG-NORMALITY OF ECONOMIC DATA
10
15 20 30 40 50 60 70 80 85 90
PERCENT HAVING KPYE LESS THAN INDICATED
Figure 7
-15k-
95
-------
increased to as much as 95- (The points happen to represent the distribution
of deviations from a regression line expressing the relation "between unit
cost of sanitary land fill and annual tons,,)
What this means is that the samples, with which we are dealing, appear to come
from populations of random variables, here random waste/employee ratios, such
that the total population of these random rations has a predictable statis-
tical distribution. Why this should be so, and particularly why the
distribution should be log-normal rather than some other type of uniform
distribution, is a very intriguing question but is not within the scope of
this project. The demonstratable empirical fact is that the distribution
is indeed log-normal in practically all cases,, Therefore, it is possible
to achieve some useful predictions, together with confidence limits thereon,
from the relative small samples available. The procedure is described be]ow.
The discrete sample distribution plotted on log probability paper is taken
as approximating the distribution of the entire population of waste/employee
ratios for establishments in the S.I.C. codes. A straight line, the log-
normal line, is drawn that best fits the points. The sample points
approximate this line and the axiom is that the real population points will
even more closely approximate this line. Accordingly, the median of the
line is taken as the median of the population and the standard deviation
of the line as the standard deviation of the population, of course in log
units. The median is the middle logarithm in a large number of logarithms
normally distributed, and the absolute value of the median, that is the
anti-log of the median is also the median among all the absolute values of
the corresponding points, i.e. among all the anti-logs of the logarithms.
If the logarithms are indeed normally distributed the average of the
logarithms will be equal to the median log, since this is characteristic
of any normal distribution.
However, the average of the absolute values, that is of the anti-logs, will
not be equal to the anti-log of the median or to the anti-log of the mean
log. It is easily proved qualitatively that whereas the summation of all
the logs in the population is obtained by taking the mean or median log and
multiplying it by the number in the population, the summation of all the
anti-logs is not obtained by multiplying the number in the population by
the anti-log of the mean log or the anti-log of the median log. The average
of the anti-log, that is of the absolute values, will be greater than the
anti-log of, that is the absolute value of, the mean log. Stated in the
terms in which it is actually used, this is the number (for example, the
average waste/employee ratio), such that when multiplied by the number in
the total population (the total number of establishments in the S.I.C.
codes) is the summation of the total population (total waste per employee),
The average of the anti-logs, i.e. the average waste/employee ratio has a
ratio to the median of the distribution which is a function of the standard
deviation in log units, and of the number in the total population. This
ratio between the arithmetic average and the median of a log-normal
distribution is termed the lambda factor, symbol A. . The lambda factor
allows one to compute the arithmetic average from the median if the popula-
tion is log-normally distributed.
-155-
-------
An example of how the X factor is obtained from the data is presented below.
Table XM shows the data obtained from S.I.C. code 23; nine (9) interviews
resulted in value of Kpye ranging from .12 to 2.39. First a regression line
was fitted to the following function:
log(lO Kpye) = A + B(employees)
to determine if log(lO Kpye) was a function of size of establishment. The
correlation coefficient, R, equals .08^38, and indicates that log(lO Kpye)
was not a significant function of establishment size.
Next the data was plotted on probability paper as shown in Figure 8 to
indicate that the distribution is log-normal.
TABLE XXII
ARRAY OF KPYE DATA
CODE 23 - APPAREL
Int. No.
Number of
Employees
Waste/Employee
Ratio
Kpye
23-1
23-2
23-3
23-4
23-5
23-6
23-7
23-8
23-9
15
14
530
8
500
175
35
50
170
.705
2.390
1.510
.251
.264
.120
.350
.388
.910
-156-
-------
LOG NORMAL DISTRIBUTION
OF SOLID WASTE PER EMPLOYEE RATIOS
FOR APPAREL (S.I.C. CODE 23)
a:
O
z
D
O
£L
O
Z
3
O
Z
.1
UJ
LU
O
_l
0.
2
UJ
Q
_l
O
.01
84 Percentile= 1.33
N = Number of Points = 9
S = Std. Deviation in Log Units = 0.417
-------
The lambda factor is then calculated as follows:
In
k
= ratio of average of anti-logs to median of the log-normal distribution
with a ratio and number in universe given, i.e. total number of
establishments in S.I.C. Code 23.
= logarithm to base e
= In a, standard deviation in In units
Let a = a ratio
n = number in universe, i.e. the number of establishments in total population
P(z) = area under standard normal curve from zero to z. This table can be
identified by: z = 0 P(z) = 0
z = i.o P(z) = -3413
z = 2.0 P(z) = -4772
z = 3.9 P(z) = .5000
where:
In x - In x
k
2 P(z) is the probability that z will be between In x +_ k
P (y) signifies the z value such that P(z) = y,e.g. P"1 (0.4772) = 2.0
,-1
n + 1
-0.5
= the z where P is
^TT-°-5j
zl = ~Z2
N(z) = P(z) + 0.5, for z > 0
or
Then:
0.5 - P(z), for z < 0
a,n
z0-k
2
N(z)
Zi -t
n-1
n+1
As n ->
-158-
-------
The second term on the right hand side is a significant correction factor
if n is less than a very large number; in our case, the number of establish-
ments. For example, values of X are presented below for two o ratios.
X for X for
o ratio = 2 o ratio =
10 1.119 1.U2
100 1.228 1.92
1,000 1.262 2.122
10,000 1,270 2.190
If you go through the above you will find:
X2.61, 26,000 establishments = 1,56
Computation of Kpye mean for Code 23:
median = 0.508
o2.61s 26,000 = 1.56
Kpye mean = 0-508 x 1.56 - -792
The preceding statement requires that the X factor itself be precisely known,
that is, without dispersion. However, since the X factor is a function of
the standard deviation and the standard deviation of the population itself
has a confidence interval, this means that the X factor also has a unique
confidence iterval. When this dispersion of the X factor is taken into
account, it produces a confidence interval upon the arithmetical mean which
is greater than the one used in this study. Quantification of this effect
awaits completion of the theoretical studies mentioned,
This development rests on the observed empirical fact that samples from
populations of economic data, and specifically from waste/product and waste/
employee populations, tend to approximate a log-normal distribution and
that the entire population of such data closely approximate a log-normal
distribution and that the greater the number in the sample the more closely
the sample distribution approximates a log-normal distribution.
-159-
-------
In the very few cases studied in this project where the distribution was
not log-normal (and also not normal incidentally), the standard conventional
statistical procedures were applied on the arithmetic values. It is known
how to proceed from the median to the estimated total of the population when
the distribution is normal, and the method outlined herein provides the means
for proceeding from the median to the estimated arithmetic total of the
population when the distribution is log-normal. However, the means for
accomplishing this when the distribution is neither normal nor log-normal
are not yet available to this study and the number of incidences of such
requirements are so small as to not warrant their further exploration.
Therefore, in these two the data were handled in the conventional manner
as if they were arithmetically normally distributed in which case the
arithmetic mean is the best estimate of the population mean.,
-160-
-------
SECTION XII
THELO NQgMAL ,1 TYOFTH gMU.LTI^CODE SAMPLED
It has been stated, as an empirical observation, that small samples from
populations of waste/employee ratios tend to approximate a log-normal
distribution , that the greater the number in the sample the more closely
the sample distribution approximates log-normal, and that by extension the
entire population of such data closely approximates a log-normal distribu-
tion. Figure 7 shows two of the sets of samples of waste/employee ratios
from two different S.I.C, codes, one showing a high degree of approximation
to log-normal and the other one of those most deviant frLm log-normal which
still was used as log-normal in the projections. Also shown on Figure 7 Is
a set of different economic data comprising 95 points to show how large
samples even more closely approximate log normality.
It would be highly desirable to demonstrate with actual waste/employee data
that as the size of the sample in a given code is increased the distribution
of the sample more closely approximates a log-normal distribution. Unfor-
tunately, it is not warranted to collect additional waste/employee ratios
by interview in a single code solely for this demonstration. However, there
are available some scores of waste /employee ratios for different codes and
it is possible, by statistical reasoning to be described, to generate from
these a set of data points which do have a common distribution.
The distributions for the two codes on Figure 7 have different means and
different standard deviations. In each case, the logs of the numbers are
normally distributed but the means and standard deviations, that is the two
parameters which determine the position and slope of the line, are different,
It is possible to so "reduce" the value of each data point so as to bring
these means and standard deviations into coincidence. The procedure is that
used in developing the standard deviate table, the z table, familiar to
statisticians .
Let: ? ,
be the logs of the individual values, n. in number, for one set and:
J
K.
nk in number, those for the second set. These sets have means j and k and
standard deviations s' (j) and s' (k) and approximate straight lines on
normal probability paper with mean j and standard deviation s' (j) and k and
s' (k), respectively.
-161-
-------
Now form new sets of values as:
(j-L-j)> (J2 -j), , (Jn -j), and (k -k), . etc.
J
These new sets will have the same means, namely zero, and will "be distributed
in the same way as the original values were, namely approximating normal with
standard deviation of s' (j) and s' (k). The points will be scattered around
the straight line in the same manner as the original points, and the curves
will look like the original curves displaced downward to have means of zero
(1.0 on the log scale of Figure 9). However, they will have different
slopes.
To reduce the slopes to a common value form new sets:
9-j) (k -k) (k -k)
Each of these new values represents the number of standard deviations by
which the value differs from the mean. When the distribution of these is
plotted they will also look like the original sets but will now have not
only the same means but also the same sta; dard deviations, actually 1.0.
Two such "reduced" distributions with means of zero and standard deviations
of 1.0 are shown in Figure 9 drawn from the Kpye's for two actual codes
studied.
These two sets of points, instead of being samples from two separate
populations, i.e. two separate S.I.C. codes, are now samples from popula-
tions each of which has a mean of zero and a standard deviation of 1.0,
In other words, they are samples from a single population having a mean of
zero and a standard deviation of 1.0. They are thus two separate samples
each having their own individual dispersions from the same population.
If in conventional sampling work we have two samples of six each from the
same population, we may equally well take them as one sample of twelve from
that population. The sample of twelve will give a better estimate of the
characteristics of the population than will either sample of six. By this
reduction process, therefore, we have utilized the individual code data
which in its original form could not be combined to produce a single sample
which has the characteristics of the dispersion typically found in S.I.C.
codes. In other words, the numbers we now have are such as would be
obtained by taking a sample of 12 from a single code. Therefore, they should
themselves have a distribution which, if our axiom is correct, should more
closely approximate the ascribed distribution of the population than do the
samples from the individual codes themselves. Such a manipulation has
actually been performed on the two sets of data in Figure 9 and the result,
the distribution of all points in the two codes, is shown as the curve
labelled "combined Z value". It is seen that the line representing these
-162-
-------
Z VALUE DISTRIBUTION PLOT
Ul
O
Q.
u
>- -z.
OQ <
O in
ill O
O
z
oe.
in
m
99
1.6
1.4
1.2
1.0
.8
.6
.4
.2
0
.2
- .4
- .6
- .8
- 1.0
1 9
- 1.4
- 1.6
- 1.8
-2.0
0.
99
99
01
O.C
.9 9
99.8
[o.l 0.5
5 0.2
? 7
98 95 90 80
:
Con
f
L
ibin
/
ed
:0d
4
1
1 , i
in
i
J
Z V(
e 2
^
X>
'1
/
)
I 10 20
5 3
0 5
60
ilu
I
1
f
(
e
i
(
y
1
^
40
0 5
0 3
40
1
A
1
r\
I'
3 1(
20
f
t
ii
I
i\
r*
Stcmdar
- Normal
Distrib
60
0 7
d
ut
1
I
1
1
) £
* /
/
'
'K
i
c
on
ade
, 0.
/ 2 1 0.5
1
80 90 95 98
0 9
2 0.
0.1
99.8
9 99
05
0.0
99.
.9
PERCENT HAVING VALUES LESS THAN INDICATED
Figure 9
-163-
-------
pooled samples more closely approximates the straight line over most of the
field. Attention is directed particularly to the upper end at which it is
considerably better than either of the individual samples. The reason for
this is that one of the samples is low in this region and one is high.
Thus, when they are plotted as a pooled distribution, the highest one becomes
the highest value and the lower one becomes the second highest. It is this
random nature of the individual samples which causes the pooled line to more
closely approximate the straight line. At the lower end, this improvement
has not occurred with the two samples shown because it happens that both
samples have low points in the low percentiles. However, other random
samples, i.e. other codes, will have points which are high in the low
percentiles and the line pooled with these will more closely approximate
the straight line. In terms of a sample of increasing size from a single
code, this means that the samples taken happen to have points which are
high in the low percentiles and the line pooled with these will more closely
approximate the straight line. In terms of a sample of increasing size from
a single code, this means that the samples taken happen to have points which
do not fall on the line at the low end; however, as additional data poirits
are added to the sample, these points will find themselves displaced to
lower percentiles where they will fit on the line. Figure 10 shows a pooled
distribution in the reduced form for all 122 Kpye values taken from ten
codes having these in the present study. Thus "super code" is a projection
of what would happen if the number of points in the sample for any particular
code could be multiplied several fold. Also it shows the direction toward
which the distribution would trend as the sample 'size approached the
population size. If the distribution of the reduced values was not normal,
that is, if the distribution of the original value was not log-normal, then
if the populations from which the samples are drawn had some uniform type
of distribution, the pooled curve would approach a curve representing that
distribution on the normal paper. But it would not approach the straight
line representing an original log-normal distribution. Likewise, if say
half the sample had log-normal distributions and half had normal
distributions, in that case also the pooled line would not approach the
straight line on Figure 10. This demonstration may be taken as showing
that the distribution of population in any code approximate log-normal.
Of course, when reconverted to the "unreduced" form, the distributions for
each of the codes will have different means and different standard
deviations but they will be log-normal.
-164-
-------
DISTRIBUTION OF 122 "REDUCED" OBSERVED KPYE VALVES FROM 10 CODES
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
.8
X
1 -6
>- z
CQ <
uj 4
O Ul
5n -2
g| 0
It "2
i- 5 4
^z
o 6
o; o_
Ul
03
i ~ -8
z
1.0
- 1.2
- 1.4
1 A
1 ft
o n
0 0
- 2.4
- 2.6
0
'/
/
f
1
f
/
+
1
1
i
ft
f
01 | O.l| 0.5 1 2 5 10 20
0.05 0.2 3
y
f
i
L
ir
s
f.
D
<
^
/
1
tando
orma
istrib
d
utic
^
IT
n
/
i
/
/-
A
/
/
/
40 | 60 | 80 90 95 98
0 50 70 9
/
99. 8| 99.
? 99.9
99
PERCENT HAVING VALUES LESS THAN INDICATED
Figure 10
-165-
-------
SECTION XII
APPENDIX D
MATHEMATICAL flANDLING OF DISPOSITION AND DISPOSAL DATA
Disposition is defined as the operation carried out on the waste between
the point of production and the point of ultimate disposal. This usually
comprises a conveyance operation frequently spoken of as "hauling".
Ultimate disposal is defined as the waste handling operation which finally
places the waste beyond further human contact. A reduction is defined as
a process carried out on the waste to reduce its weight or volume prior to
ultimate disposal. Incineration and other forms of burning are actually
reduction operations since they reduce the weight and volume of waste
but produce a residue for ultimate disposal. While it violates the strict
definitions of these operations, incineration has been classed with ultimate
disposal in the studies in this phase on disposition and disposal. It is
implicit, however, that when incineration is mentioned among the ultimate
disposal operations, it is the reduction operation that is actually meant.
The waste streams in the interview establishment were described as to type
but then were grouped together for further analysis such that all waste
streams having the same disposition and disposal were included in one group.
Thus, if for example, plant trash and shipping waste were handled by the
producer in his own incinerator, while process waste and sludge from liquid
cleaners was contract-hauled to the city sanitary land fill, these two
classes of disposition and disposal would be handled separately and counted
separately in the tallies. In the case described there would be one tally
for self-disposition and one tally for contract disposition. There would be
one tally for self-ownership of the ultimate disposal facilities and one
tally for city ownership. In this instance, the number of "disposition and
disposal situations" would be two.
As implied in this illustration, the characteristics of the disposition
disposal operation which were categorized were disposition by self, by city,
or by contract, i.e. disposition agent; ultimate disposal by type, i.e. open
dump, open burning, sanitary land fill, incineration, tepee burner, etc.;
and ultimate disposal by facility ownership, self, city contractor owned,
merchant.
For every interview in each S.I.C. code and for each waste stream group as
described above, this disposition agency, ultimate disposal type, and
ultimate disposal facility ownership was tallied and compared with the sum
of all waste stream group tallies in that category. For example, in the
illustration above, it would be stated that the disposition was 1 self, and
1 contract, the ultimate disposal was 1 incinerator, and 1 sanitary land
fill, the disposal facility ownership was 1 self and 1 city. In some
instances, it was possible to be more explicit, as for example to describe
the ultimate disposal type and ownership together with one statement as
comprising one self incinerator and one city sanitary land fill.
-166-
-------
The method of analyzing disposition and disposal data just described provides
frequencies of occurrences among all disposition or disposal occurrences.
From such a frequency analysis one might develop results such as that a
certain percentage of disposition occurrences were "by contract. The
occurrences are not limited to one per establishment but there may be as
many disposition occurrences and disposal occurrences as there are
separately handled waste stream groups in the establishment.
There are two other possible methods of handling disposition and disposal
data. One of these would involve summing up the quantities of waste found
in the sample to have a particular disposition or disposal mode and
expressing this as a fraction of the total waste in the sample. In contrast
to the frequency method which gives the fraction of occurrences this method
would purport to give the fraction of the total waste having a particular
disposition of disposal mode. However, such results would be definitely
erroneous for the following reason. There is no evidence in the data that
large establishments tend to one form of disposal or disposition while
small establishments tend to another form. However, handling the data in
the manner just described and then ascribing the percentage results to the
universe required the assumption that the large establishments which happen
to be in the sample are representative of all large establishments in the
population and likewise with the small establishments. But with such a
small sample, it is just as likely that in the next such sample the large
establishment would have a quite different mode of disposition. It is not
possible to strictly test this concept (that there is no trend of disposi-
tion mode with size) with such a small sample as is available to the project,
but there does not seem to be any physical reason which would demand it.
To test the concept would require a considerable number of interviews in
each of several size classes in order that the frequencies of the various
modes might be compared as a function of size class. This, of course, is
out of the question with the number of interviews assigned to this study.
A better estimate of the percentage of total waste going to each disposition
mode may be obtained by a procedure intermediate between the preceding two.
If, for each establishment, there is expressed the percentage of its total
waste going to each disposition mode then the sum of the percents for a
group of establishments in each disposition mode divided by the number of
establishments gives the average percent to that disposition mode. Compared
to the first method, this method provides some information on quantities
as well as frequencies. Compared to the second method, this method avoids
the weighting of the percentages by the amount of waste which was undesirable
if disposition mode is not dependent upon size. If each establishment had
only one mode of disposition, that is had either 100% or 0% in each
disposition category, then the frequency method and this intermediate
method would give the same results. However, since establishments sometimes
-167-
-------
have more than one mode of disposition, the results of the two methods will
differ somewhat. This intermediate method also suffers from the smallness
of the sample but the possibility has "been eliminated that the chance
inclusion of a large establishment in the sample might overweight the
results.
Up to this point the discussion of disposition and disposal has been in
terms of a waste stream which requires ultimate disposal and thus is of
interest to this project. There are such entities, however, as waste
streams within an establishment which find some satisfactory and socially
acceptable mode of disposition such that although they represent a waste
in respect to the main product, they do not represent a waste in the sense
that means must be provided for the disposition and disposal. Thus, they
are more akin to established by-products than to wastes. Such by-products
or wastes may be either sold or given away for some other use, used for
fuel in the producer's establishment, or utilized for some other purpose in
the producer's establishment. In any of these modes, the producer does
not actually have a waste problem, nor is it of concern to this project,
since while usually not producing a great profit these operations are
ordinarily conducted without cost to the producer or at a very nominal cost.
Unless there is some change in the established utilization pattern the
wastes are not likely to appear back in the general waste stream. Examples
of these modes are wood chips sold for pulp-making, stockyard pen waste
given away for fertilizer or to be processed into fertilizer, paper scraps
and broke, repulped in the producing establishment or sold as waste paper
for other establishments to utilize.
Mathematically, this project has two methods of handling such by-products.
These two methods involve either including such by-products in the waste
upon which the waste/employee or waste/product ratio is computed or not so
including them.
If it is the common practice, i.e. practically universal and consistent, to
have a by-product disposition for some waste stream, then this waste stream
is not considered at all in the study. An example is the utilization of
wood chips in the saw mill industry in the South and East. It is practically
universal to sell these chips to the pulp mills, and therefore, it is only
rare in the interviews and in the real population that these chips enter
into the waste stream of interest. Accordingly, they are not considered
at all as a waste in developing the waste/product ratio. At the other"
extreme, if in a few interviews it is found that mill work establishments
occasionally give away a pickup load of wood scraps to some individual for
home heating, this is not even excluded from the waste stream since both
quantity and frequency are so small.
It is when the frequency of occurrence becomes high and the fraction so
disposed is simultaneously high that some judgement must be used in deciding
whether to include the waste in the waste/employee ratio or not. In general,
the decision has been to include this \\aste in the waste/employee ratio
analysis, and to drop it out later from the projection of the total waste
-168-
-------
of interest by a means to be described. The reason for including it is
that to exclude such random occurrences would considerably increase the
dispersion of the waste/employee ratio depending upon whether the establish-
ment having excludable waste happened to have a high waste/employee ratio
or not. For example, if 50% of the saw mills burned 80% of their waste
sawdust and shavings for fuel, then the waste/employee ratio for that half
of them so doing would be only 20% of the waste/employee ratio for those
not so doing even^ if the basic generation of waste per employee were
identical in all the establishments. Thus, it seems preferable from the
standpoint of obtaining lowest possible dispersion in waste/employee ratios
to include all waste stream dispositions except when such by-product utili-
zation is almost universal. The exclusion of the by-product from the final
waste stream is done by the intermediate method just previously described.
-169-
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information system
(volume iii)
-------
TECHNICAL - ECONOMIC STUDY OF SOLID WASTE
DISPOSAL NEEDS AND PRACTICES
VOLUME III - INFORMATION SYSTEM
Conducted for the Public Health Service
under Contract //Ph 86-66-163
Prepared by
Peter W/Kalika
Project Engineer
Product Diversification Department.
Itct
James E. Seibel /
Product Analyst
Product Diversification Department
COMBUSTION ENGINEERING, INC,
WINDSOR, CONNECTICUT
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. SUMMARY ..... 1
II. INTRODUCTION 2
III. CONCLUSIONS 4
IV. RECOMMENDATIONS FOR FUTURE ACTIVITIES ... 6
V. DISCUSSION
A. THE SOLID WASTE INFORMATION PROBLEM ... 7
B. INFORMATION SYSTEM OBJECTIVES ...... .... 14
C. ALTERNATE SYSTEMS ...... ........ 19
D. EVALUATION OF SYSTEMS ..... 41
E. SPECIFICATION FOR A PILOT SYSTEM 49
VI. REFERENCES 54
VII. APPENDICES
A. QUESTIONNAIRE AND INTERVIEW PROGRAM .... 55
B. COST CALCULATIONS FOR SYSTEMS EVALUATIONS .... 92
C. SAMPLING OF REFUSE COMPOSITION 103
D. STATISTICAL SAMPLING OF MUNICIPAL REFUSE DATA ....... 106
-i-
-------
m
SECTION I
SUMMARY
A feasibility study has been conducted which assesses the need for a solid
waste information system. The opinions of those responsible for solid waste
lanagement, as determined through questionnaire responses and personal
interviews, indicate that significant inadequacies exist in the information
available and that this is having a marked effect on the capability of
these administrators to effectively plan and execute solid waste activities.
In the opinion of those approached, an information system would provide a
meaningful and effective aid to administrators, so long as it were designed
to serve their specific needs at a minimal cost. The most significant
information gaps are in the areas of land requirements and facilities
performance. In addition, to be most effective, a solid waste information
system should provide some means to assist planners, administrators and other
decision makers in the performance of their tasks. A system which provides
a data clearinghouse service, a predictive information service and a planning
information service would best meet the needs of solid waste planners and
decision makers of all levels.
The data clearinghouse service would make available data which is pertinent
to solid waste activities. The predictive information service would provide
standardized trend predictions of significant solid waste parameters such
as growth in pounds per capita of municipal, commercial and industrial
solid waste. The planning information service would apply computer based
mathematical models to solid waste planning and decision making questions.
The complete system is discussed as System #7 in this report. The cost of
such a system appears to be reasonable in relation to the potential benefits
to the users. The potential cost for installing, operating and maintaining
such an information system to serve the entire country would be approximately
$13 million over a ten year period. Its potential savings have been con-
servatively estimated at about 5 percent of the total cost for new incinerator
installations over the next ten year period. This alone offsets the ten
year estimated cost of such a system.
It is recommended that an information system to serve the field of solid
waste management be developed. Since the scope of the current study was
necessarily limited, the initial steps in implementing this recommendation
should include a more detailed study to refine the system concepts and cost
estimates and to establish the preferred management organization.
A pilot system is recommended as a means to investigate proposed systems
and techniques in sufficient detail to determine their feasibility and to
establish the degree of sub-division required in an ultimate system to
serve the entire nation. Preliminary design requirements for a pilot system
to serve a limited area are included. An appropriate pilot system could be
established and operated for four years for a total cost of approximately
$1.3 million.
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SECTION II
INTRODUCTION
Solid waste management has become a significant problem throughout the
country and the cost associated with it has moved it into the category of
big business. However, this field has been consistently plagued by lagging
technology, high cost, pollution hazards and public criticism. Much
individual effort has gone into attempts to upgrade the management of solid
waste and to obtain gains in the performance of equipment and facilities, but
such efforts have suffered from a lack of available information and a means
for the interchange of experiences, successes or failures. This situation
makes clear the need for an effective information system to assist planners
and decision makers concerned with solid waste management.
An information system study program has been conducted as a part of the over-
all efforts by Combustion Engineering under contract Ph 86-66-163 in order to
more precisely define the problem on the various Government levels, and in
the private sector of solid waste management.
The results of the total program are reported in four volumes.
Volume 1 - Municipal Inventory
Volume 2 - Industrial Inventory
Volume 3 - Information System
Volume 4 - Technical - Economic Over-view
The study presented in this report (Volume 3) was initiated with a question-
naire and interview program, and a study of the available literature. These
steps defined the information needs and determined whether an information
system could satisfy the needs. The results have led to a statement of the
information problem at various decision making levels, the compilation of
system objectives, and the development of several alternative information
systems to serve the field of solid waste management. These systems have
been evaluated by a comparison of the extent to which each achieves the system
objectives, and by a comparison of the costs with the benefits to the infor-
mation users. The system which seems to best serve the overall objectives
has been selected.
Further discussion is included on statistical sampling techniques which could
be used to obtain adequate data inputs, and on the nature of other potential
inputs and outputs from an information system. A specification for a pilot
model of the recommended information system concept has also been developed
and recommendations are offered for its implementation.
More extensive discussion of several phases of the work is incorporated in several
appendices. These include a report on the questionnaire and interview
program, detailed cost estimates of alternative systems, and a discussion
of statistical sampling and refuse composition sampling.
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This report was prepared by Peter W. Kalika and James E. Seibel of the
Product Diversification Department, David R. Pearl, Manager. Mr. Marshall
Spieth of Combustion Engineering's Corporate Systems Group participated in
a consulting capacity. Mr. Ralph Black was Project Director for the Public
Health Service; Mr. Elliot D. Ranard was Program Manager for Combustion
Engineering, Inc.
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SECTION III
INCLUSIONS
A. The field of solid waste management is plagued with a significant lack
of reliable information in a standard form to assist planners and decision
makers in effectively performing their functions. Although some
elements of information are available normally, these are not usually
either complete or extensive enough for planning and decision making
needs.
B. The greatest lack of information is in the areas of land requirements
and facilities performance. These, and other information elements, are
necessary for effective long range planning, which has been identified
as the primary decision area in the solid waste field.
C. Solid waste management at all levels seem to welcome an information
system if it served their specific needs for information and for plan-
ning assistance at minimal cost. An appropriately designed and managed
solid waste information system could overcome many of the present infor-
mation inadequacies and could provide significant assistance to solid
waste planners and decision makers
D. To be most effective, a solid waste information system should both pro-
vide the information necessary for more effective planning and decision
making and should provide some means to assist planners, administrators
and other decision makers in applying the information supplied to them.
E. Several alternative solid waste information system concepts have been
evolved to assist planners and decision makers to varying degrees in
performing their functions. The systems can either provide the means
to improve information availability, provide the means to make available
various decision making criteria, or both.
F. An information system which provides both information availability and
decision criteria would best meet the needs of solid waste planners and
decision makers at all levels. The cost of such a system appears to be
reasonable and compares favorably with the potential benefits available
to the users.
G. An information system which would provide decision criteria could either
develop statistical trends on a regional basis, a "predictive information
service", or it could provide information on an individual request
basis, a "planning information service", or both. The "predictive infor-
mation service" could satisfy the most important user needs, and the
"planning information service" the remaining needs. There would be a
15 percent cost increase for providing both features over just providing
the "predictive information service". The additional benefits co the
users far outweigh this slight additional cost.
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H. The potential cost for providing and maintaining a complete information
system which would most effectively serve the needs of the users would
be approximately $13 million over a ten year period, including initial
and annual operating costs. This cost would support a system serving
the entire nation.
I. Potential benefits available to the users from an established information
system include:
1. Knowledge of the availability of standardized, ready-to-use,
geographically representative data which could be quickly obtained.
2. The benefit of sophisticated and proven computer usage and techniques,
regardless of community size and means.
3. Assistance in assuring that future plans are sufficient and timely.
4. Savings in providing effective solid waste collection and disposal
facilities.
The value of these benefits significantly exceeds the estimated cost of
the complete information system.
J. A pilot system to serve a limited area is the best means for initiating
an effective total solid waste information system. The results of pilot
system operations would define more precisely system parameters and
management requirements of a total system to serve the entire nation.
An appropriate pilot system could be established and operated for four
years for a total cost of approximately $1.3 million.
K. The sampling of municipal refuse to determine chemical composition and
heating value on a standardized and widespread basis would be expensive
with little guarantee of success. The basic information which can be
developed from accurate measurements of refuse quantities and related
parameters is initially more important and less expensive. Detailed
chemical sampling could be considered as a later phase of an information
system. However, the sampling of certain selected physical and chemical
characteristics will be necessary in the evaluation of systems for
salvage and reclamation and should be undertaken as needed.
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SECTION IV
RECOMMENDATIONS FOR FUTURE ACTIVITIES
A. The development of an information system to serve the field of solid
waste management should be taken under consideration by the Solid Waste
Program. The system should include a "predictive information service"
function, a "planning information service" function and a "data clearing-
house service" function. This system could serve the entire nation
through a number of local information centers.
B. Since the scope of the current study was necessarily limited, the initial
steps in implementing the above recommendation should include a more
detailed study to refine the system concepts and the estimates of their
costs and to establish the preferred management organization.
C. Consideration should be given to the initiation of a pilot information
system to serve a limited geographical area as a means to define more
precisely system parameters and management requirements of a total system
to serve the entire nation. The pilot system should encompass all of the
features of the full scale national system, and upon completion should
be capable of virtually complete integration into the overall system.
The pilot system developed should encompass a sufficiently large and
representative region of the country and should contain certain minimal
historical and planned solid waste activity. It should investigate
proposed systems and techniques in sufficient detail to determine their
feasibility and should establish the degree of sub-division required in
an ultimate system.
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SECTION V
DISCUSSION
A. THE SOLID WASTE INFORMATION PROBLEM
The solid waste management field has been plagued consistently by lagging
technology, high costs, pollution hazards, inefficient performance and
public criticism. Much effort by individuals and individual municipalities
has gone into attempts to upgrade the management of solid waste and to
gain in performance efficiency. Such efforts have been expensive and
sometimes less than completely effective because they must be accomplished
on an individual basis with only limited means for an Interchange of
experiences, successes or failures. Because of such efforts and because
the overall problem is not improving significantly, improved planning
and decision making in the solid waste management field has become of
increasingly greater concern to Government officials.
A primary reason for the existence of such problems as well as a primary
deterent to finding more effective solutions to them is the present lack
of reliable information and communication of information throughout the
solid waste field. This situation defines the basic need for an
effective information system to assist the planners and decision makers
concerned with solid waste management.
In order to more precisely define the problem on various governmental
levels and in the private sector of solid waste management, a question-
naire and interview program was conducted, along with a study of the
available literature in the field. The development of the questionnaire
and interview program and the specific results obtained are described
in detail in Appendix A, and the flow of information in municipal
refuse activities is shown in Figure 1. The application of the results
obtained to the development of a solid waste information system will be
discussed in the following paragraphs.
1. PRIMARY DECISION AREAS
The primary decision areas for each category of participant in the
solid waste field are discussed in Appendix A and indicate that the
majority of the categories consider long range planning as their
primary decision area. State planners consider the evaluation of
performance of refuse facilities as their primary decision area.
This also represents the second most important decision area for
all the categories as a total. Evaluating effectiveness of plans
rates as the third most important decision area for the total list
of categories.
2. INFORMATION REQUIRED FOR PLANNING AND DECISJONJIAKING
The specific types of information considered most important by
solid waste management officials are related to the first and second
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decision areas of primary concern. These categories include infor-
mation on land requirements, facilities performance, refuse quantity
and costs of refuse activities, and would obviously be of primary
concern for making long range plans and for evaluating the per-
formance of refuse facilities.
3. INFORMATION NORMALLY OBTAINED BY REFUSE MANAGEMENT OFFICIALS
The categories of information which are regularly obtained by refuse
management officials are also shown in Appendix A. Significant
variation exists in both the type and amount of data normally
obtained because of the great differences which exist in record
keeping. Data is normally obtained on facilities performance,
refuse quantity, population and costs of refuse activities. State
and regional planners also appear to obtain data on land requirements,
although only about one-third of the municipal planners normally
appear to obtain such data. It is also significant to note that
only equipment manufacturers and consultants normally appear to
obtain information on air pollution control a subject which is
currently receiving a great deal of public and Government attention,
4. INFORMATION GAPS
The information gaps can be defined as the differences between the
information stated as necessary for proper planning and decision
making and the information normally obtained by refuse officials.
The categories of information which had to be specially obtained pro-
vide a good indication of the nature of these gaps. Appendix A
illustrates the type of data that has had to be specially obtained
by each of the decision maker categories. Data on land require-
ments frequently had to be specially obtained. But, in addition,
data which was normally obtained, such as facilities performance,
refuse quantity, and costs of refuse activities, was also quite
frequently specially obtained. This indicates that normally obtained
data may often be insufficient or incomplete for the decision
required. Examples of data not considered important but which was
specially obtained are data on air pollution, refuse composition and
population. These will probably become more important with time.
The primary usefulness of special data was in "providing a more
accurate basis for decisions". Only manufacturers and consultants
did not give this their first vote. These rated "more accurate
design of facilities" as first choice. Since the primary usefulness
of data is a "more accurate basis for decisions", and many of the
categories have sought additional data in areas where data is
normally received, then the data currently received on a normal
basis is apparently not entirely adequate for decision making.
5. WHAT NEEDS TO BE DONE _TOJ1AKE._THE__INFOEMATION_JJSJFUL
The raw data is often not very useful to the planner or decision
maker until it has been standardized, processed or rearranged in some
way. Solid waste management planning and decision making involves
-------
the application of judgment to a large number of variables and
related factors. To apply judgment or to arrive at conclusions
with too little data is perhaps no more difficult than being given
too much data in an unassembled, uninterpreted form. Therefore, the
raw data must first be processed or prepared in some way before it
becomes a useful tool.
To be useful as a long range planning tool, parts of the data need
to be developed into trend projections. Such trend projections
should be developed for factors such as population, solid waste
production, land availability or depletion rate, and refuse composition
or heating value. Cost and performance information need to be
defined in terms of what they include and preferably should be put
into a standardized form. The data collected should be validated to
assure its accuracy.
Planners and decision makers are most interested in what might occur
and what steps should be taken, rather than in the individual
details of bits and pieces of information. To arrive at an analysis
of what might occur, the data collected needs to be interpreted for
its significant meaning and implications for the future. It needs
to be compared with historical data and with predicted trends.
Quantities, timing and effect must be extracted from the data.
To arrive at the recommended steps to be taken, the future trends
must be analyzed for possible effects and the probable means for
managing the expected occurrences. Alternate facilities and manage-
ment means need to be developed and the optimum approach must be
found. Timetables for activities must also be developed on the basis
of the timing needs indicated by the data. Optimization techniques
may require the application of computerized data processing techniques.
Such techniques can be applied to the data for both planning and
operational optimization purposes.
6. GOVERNMENT INFORMATION REQJJ1REMENT_S
Government agencies at various levels are responsible for performing
certain regulatory, enforcing or legislative functions concerning
the management of solid waste. In order to carry out these activities,
they have needs for certain data and information on solid waste
operations and their effects on the general public. Agencies on the
federal level are primarily concerned with nation-wide trends in
solid waste management, with research activities to upgrade the
management and handling of solid waste, with assisting state and
local governments in improving solid waste management functions
and with the promotion of adequate state and local solid waste
legislation and regulations to safeguard the health of the public.
To carry out the planning and administrative activities necessary
to accomplish these functions, the federal agencies need information
on trends which affect solid waste management, and information on
the effectiveness of local solid waste programs. They would also
require information on research and development activities which could
-------
lead to improved solid waste planning and operating functions, and
they require means for disseminating available information to those
who could use it.
Agencies on the state level, most often the state departments of
health, have indicated that their primary concern is with the evaluation
of refuse facilities performance. They are also concerned with
establishing standards and regulations and with insuring that local
solid waste programs comply with them. State agencies must also be
concerned with assisting the local officials in obtaining public
support for solid waste programs. The information needs of these
agencies in performing their required functions include significant
trends which affect solid waste activities, land requirements and
availability, facilities performance characteristics, refuse quantity
trends, population characteristic trends, and costs of refuse
activities. To establish standards and regulations, they also
require information on the effects on public health of solid waste
practices and information on research and development activities
which could lead to improved solid waste planning and operating
functions. In order to monitor the performance of refuse facilities
and the extent of adherence to standards and regulations, the state
agencies would need information on the operation of local solid
waste programs and would periodically conduct on-site investigations
and reviews.
Regional planning agencies are primarily concerned with long range
planning of solid waste management programs for an entire region,
with the obtaining of public support for regional and local programs,
and with evaluating the effectiveness of plans which have been
initiated. In order to accomplish these objectives, such agencies
require information on land requirements and land availability,
facilities performance, air pollution causes and regulatory trends,
refuse quantity trends, refuse composition or source breakdown,
population characteristic trends and the costs associated with refuse
activities. Regional agencies could utilize the information and
means which would allow them to optimize solid waste activities within
the region.
Municipal planning agencies would be primarily concerned with long
range planning for solid waste control, with facilities planning
and installation, with establishing local standards of performance
and regulations and with the evaluation of the effectiveness of plans
which have been initiated. In implementing long range plans,
municipal planners are typically responsible for determining what
the solid waste handling and disposal needs of the city are, for
developing plans to satisfy these needs, and for arranging financing
and installation of the physical facilities required. They must be
concerned with optimization of the total cost for solid waste
management and are usually responsible for coordination of overall
solid waste management functions for their city. They frequently
utilize consultants to study and prepare plans, and contractors to
implement facilities installations. The typical relationship between
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municipal planners, municipal operators, other city, regional or
state agencies, and consultants and contractors is depicted in
Figure 1. To accomplish their required functions, municipal planning
agencies require local level information on land requirements and
land availability, time oriented requirements for land and facilities,
facilities performance, refuse quantity and costs of refuse activities,
They could utilize the information and means which would allow them
to optimize the planning and installation of new or expanded facilities
Municipal operators, on the other hand, are primarily concerned with
the operation of refuse facilities and equipment, with the evaluation
of performance of refuse facilities and only thirdly with long range
planning functions. As such, to carry out their functions, they
require information on facilities performance, equipment inventory,
refuse quantity and costs of refuse activities. They could utilize
information on the development of new equipment or facilities for
solid waste collection, handling and disposal, and the information
and means which would allow them to optimize the operations of the
solid waste management functions.
7. PRIVATE SECTOR INFORMATION REQUIREMENTS
Solid waste administration also affects various private concerns who
are directly involved in solid waste activities. Such private
concerns include consultants, contractors, equipment manufacturers
and various research oriented organizations. Consultants, in
performing their functions of analyzing local solid waste problems
and planning facilities for solving such problems, are faced with the
problem of developing data inputs on which to base their analysis
or they must depend on readily available data which is often sketchy,
incomplete or inaccurate. The task is made more difficult by the
fact that solid waste disposal technology is largely old and out-
dated. This appears to be the case because the information necessary
to upgrade the state-of-the-art is apparently lacking. The results
of consultants' efforts could therefore be improved by the avail-
ability of more and better information on solid waste activities
and practices, particularly in the areas of refuse quantity, facilities
performance,, standardized costs and land availability trends.
They could also utilize more complete information on new develop-
ments and on the results of current research.
Contractors responsible for the actual construction of facilities
and for refuse collection could utilize better information on
facilities performance and new developments and techniques in the
field.
Equipment manufacturers, responsible for developing and providing
the equipment for handling and disposing of solid waste could
utilize better information on solid waste trends, facilities per-
formance, cost factors, refuse composition and air pollution require-
ments. Latest research results and information on developments in
the field could help this group in its efforts to upgrade the state-
of-the-art of waste handling and disposal technology.
-11-
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Researchers could be aided in their tasks by the ready availability
of better information on trends in solid waste and on the areas
which need significant attention to solve problem situations.
8. SUMMARY OF PROBLEM
The solid waste information problem consists basically of an infor-
mation gap between the type and nature of information required for
planning and decision making purposes and the extent of information
normally obtained by those who require it for this purpose. The
study of this problem leads to the following summary of results:
a. PRIMARY DECISION AREAS OF GOVERNMENT OFFICIALS
- Long range planning
- Evaluations of Refuse Facilities Performance
- Evaluation of the Effectiveness of Plans
b. PRIMARY^INFORMATION REQUIRED FOR PLANNING AND DECISION MAKI_NG
- Land Requirements Information
- Facilities Performance Information
- Refuse Quantity Information
- Costs of Refuse Activities Information
c. INFORMATION_NORMALLY_OBTAINED BY PLANNERS AND DECISION MAKERS
- Facilities Performance Information
- Land Availability Information
- Refuse Quantity Information
- Population Information
- Cost Information
d. INFORMATION GAP - AVAILABLE INFORMATION INSUFFICIENT
- Land Requirements Information
- Facilities Performance Information
- Refuse Quantity Information
- Costs Information
- Air Pollution Information
- Refuse Composition Information
e. REQUIRED TREATMENT OF INFORMATLON^FOR BEST_USE
- Validation
- Standardization
- Interpretation
- Processing - Development of Trend Projections
f. PRIMARY USEFULNESS OF BETTER INFORMATION
- More Accurate Basis for Decisions
- More Accurate Design of Facilities
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THE FLOW OF INFORMATION
IN MUNICIPAL REFUSE ACTIVITIES
VOTING PUBLIC
Request for
Approval of
Bond Issue,
etc.
Approve
or
Reject
CITY COUNCIL
(or other similar
Gov't Entity)
STATE OR REGIONAL
BOARD OF HEALTH
(or other similar entity)
Recommendations
(Each Box Denotes an Entity, as labeled; the Arrows
indicate the Flow of Data and Information, as labeled.)
Operational Reports
Regulations &
Information on
Pollution
Regulations &
Information on
Sanitation
Operations
STATE OR REGIONAL
PLANNING AGENCY
Action on
Applications
for Permits,
etc.
DEP'T OF PUBLIC WORKS
(or other Planning Entity
responsible for Solid Waste)
DEP'T OF SANITATION
(or other Operational Entity
responsible for Solid Waste)
Quantities?
Costs?
Problems?
Availability?
Pollution?
Residue Quality?
Complaints?
Waste
Reduction
Operation
Supplementary Information
To Planning Consultant
Population
Data
Master
Regional
Plans
OTHER
MISCELLANEOUS
SOURCES OF
INFORMATION
Land Use
Information
Miscellaneous
'Information
All Information Available
to Dep't of Public Works
is Relayed to Planning
Consultant**
Facilities
Proposal
Planning
Reports
Quantities?
Costs?
Land Consumption?
Rodents?
Insects?
Water Pollution?
Complaints?
Land Fill
Operation
Efficiency of Routes?
Equipment Availability?
Costs?
Effectiveness of
Emergency Plans?
Complaints?
Waste
Collection
Operation
Survey
Information
As Necessary
Survey
Information
As Necessary
Survey
Information
As Necessary
PLANNING CONSULTANT
(Retained by Municipality)
DESIGNING CONSULTANT
(Retained by Municipality)
Specifications
&Bid
Requests
Preliminary
Proposals
&Bids
Specifications
&Bid
Requests
Construction
Contractor
Approved
Planning
Reports
& Other
Information
as to
Requirements
for New Facility
Preliminary
Proposals
&Bids
* Often the Planning & Designing Consultants
are one and the same, and the "Planning
Report" includes the Facilities Proposal.
^Planning Consultant May often
obtain the needed Information
directly from the Sources.
Equipment
Manufacturer
-13-
Figure 1
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B. INFORMATION SYSTEM OBJECTIVES
The previous section has discussed the solid waste information problem
and the related requirements of the Government and private sectors of
the solid waste field. The problem reduces basically to a lack of
readily available information for effective planning and decision making
in solid waste activities, and therefore, defines the need for an infor-
mation system to assist planners, administrators and other decision
makers in the field.
Before the. system can be designed, the desired objectives to be achieved
through the use of an information system must be defined. The objectives
should state the end result desired from the system, on the basis of the
problems to be solved.
Two sets of objectives for a solid waste information system have been defined.
The first set is directed toward the problem of information availability
(provide the information necessary for more effective planning and
decision making in the area of solid waste collection and disposal).
The second set is directed toward the problem of information utility and
effectiveness (provide a means to assist planners, administrators and
other decision makers in applying the information supplied to them).
These two basic sets of objectives have been sub-divided as follows:
1. Provide the information necessary for more effective planning and
decision making in the area of solid waste collection and disposal.
a. Provide the means to insure that adequate data- for any selected
system will be collected.
b. Provide the means to improve the quality of the information.
c. Provide the means to make information more readily availalbe.
d. Provide the means to standardize the information collected.
e. Provide information in a convenient and readable format.
f. Serve as a data clearinghouse system.
2. Provide the means to assist planners, administrators and other
decision makers in applying the information supplied to them.
a. Provide the means to develop predictions of trends in significant
solid waste parameters.
b. Provide the means to predict the saturation of existing facilities.
c. Provide the means to predict required capacity of new facilities.
d. Provide the means to minimize the total cost of refuse collection
and disposal.
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e. Provide the means to develop timetables for planning the
acquisition of solid waste facilities.
f. Provide the means for decision makers to request specific
information and planning services.
g. Provide the means to optimize day-to-day operations.
DISCUSSION OF OBJECTIVES
1. a. PROVIDE THE MEANS TO INSURE THAT ADEQUATE DATA .FOR ANY_,_SELECTED
SYSTEM WILL BE COLLECTED
The information system should include a means for assuring that
sufficient data is collected in solid waste activities on the
local level to match the information needs for planning and
decision making. This includes accurate data on refuse
collected, cost of refuse activities, information on population
and land availability, and inforrnation on the operation of
refuse facilities. It has been found that many communities do
not now collect this data, or only collect a portion ot it.
The achievement of this objective will be one of the more
difficult tasks of an information system. In order to accomplish
this objective, local communities must be convinced of the need
for collecting adequate data and of the potential benefits to
them of such data.
1. b. PROVIDE THE MEANS TO IMPROVE THE QUALITY__OF THE_IN_FORMATION_
Comments from potential information system users have indicated
that the quality of information available is often insufficient
for the needs of planners and decision makers. Information
quality refers to the accuracy, the reliability and the complete-
ness of the information. The common use of relatively unscientific
measurement methods, and the exclusion in many cases of factors
relevant to the definition of the data, results in a lowering
of the quality of the information usually available. Since
the results of planning and decision making depend to a large
extent on the quality of the information available for this
use, this objective is basic to the effective utilization of an
information system.
An information system could achieve this objective by providing
a means to validate the data collected by establishing criteria
for evaluation of the data, and by assuring that all relevant
factors are defined for the specific data reported,
1. c. PROVIDE THE MEANS TO MAKE INFORMATION MOREJJ.EADILY AVAILABLE^
Much of the information generated concerning solid waste is not
now available to all those who could effectively utilize it.
Much of it is publicly financed information and, therefore, should
be available for wider use. Some information, such as refuse
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and incinerator residue chemical characteristics, is unavailable
in all but very isolated instances. There presently is no
convenient means for the gathering of this information and for
making it available to those who could utilize it. An infor-
mation system, in achieving this objective, could serve as a
central agency for the gathering of this and other similar infor-
mation, and could serve the function of applying the information
to the specific cases which could make use of it.
1. d. PROVIDE THE MEANS TO STANDARDIZEJTHE INFORMATION COLLECTED
In order to make information most useful for planning and
decision making, it should be presented in a standard forme
Cost and performance information can only be of value for
comparative purposes if they are based on the same standards
and incorporate the same elements. The correlation of many
facets of solid waste data from many different sources depends
to a large extent on the inclusion of comparable factors and the
use of a uniform standardized format for its presentation.
This objective could be achieved by supplying an information
system with all of the elements and factors relevant to the data
to be standardized, and then to allow the system to organize
this data into a standardized format.
1. e. PROVIDE INFORMATION IN A CONVENIENT AND READABLE FORMAT
To be of maximum use to planners and decision makers, an infor-
mation system should have the capability of organizing information
into a form most convenient for their use. In the achievement
of this objective, particular attention should be given to
avoiding the situation where a user must browse through hundreds
of superfluous pages to reach the needed information.
1. f. SERVE AS A DATA CLEARINGHOUSE SYSTEM
The information system should serve as a collection and dis-
semination point for all information concerned with solid waste.
At present, there does not exist a single system which performs
this information distribution function for all areas of solid
waste activities, including collection, disposal and administration.
Since the information system would be the prime recipient of
information concerning solid waste, it should also logically
perform this function.
2. a. PROVIDE THE MEANS TO DEVELOP PREDICTIONS OF TRENDSJ[£_SIGNIF1CANT
SOLID WASTE PARAMETERS
The information provided as a result of the primary Objective 1
is not a sufficient tool by itself. The decision maker must
develop plans for future programs and contingencies and must
therefore develop means with which to predict the future trends
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in certain parameters. Given only basic information, the
prediction means evolved are likely to be quite inconsistent
among the users who will apply widely differing techniques and
utilize only portions of the available information. Since
under an information system, data collection, and the develop-
ment of basic information from that data, will be handled by
computer programs, it is logical that the programming be extended
to develop a unified and consistent set of trend predictions.
2. b. PROVIDE THE MEANS TO PREDICT THE SATURATION OF EXISTING FACILITIES
The question which is consistently asked first by decision
makers is, "How long will my current facility be capable of
disposing of the refuse?" Armed with the appropriate parameter
trend predictions, the decision maker is well on his way to the
answer, but certain calculations must still be made. These
combine various trends, and they require knowledge of the current
status of facilities. Although it is not a difficult or overly
tedious calculation, it is again subject to inconsistencies and
differing levels of understanding and technique. A computerized
information system can easily perform a myriad of such calculations
when supplied with the necessary data. The additional program-
ming is minimal and therefore the stated objective is considered
a reasonable achievement to expect from the system.
2. c. PROVIDE THE MEANS TO PREDICT REQUIRED CAPACITY OF NEW FACILITIES
This objective is a logical extension of Objective b. Supplied
with the trend information and with data on current facilities,
the system's calculation of the required capacity for new
facilities is straight-forward. Again, it would be possible to
perform these calculations individually, but the characteristic
of consistency inherent in a computerized information system
makes it more beneficial to perform such predictions in large
quantities. In addition, the calculations require the cumulative
and simultaneous application of several trends and can potentially
be subject to considerable error if manually accomplished.
2. d. PROVIDE THE MEANS TO MINIMIZE THE TOTAL COST OF REFUSE COLLECTION
AND DISPOSAL
This objective provides the transition from a purely information
collection system to a management information system. Whereas
the replacement of hand calculation in Objectives b and c has
been more for convenience and consistency than for necessity,
the achievement of this objective requires the application of a
computer. The number of alternatives as to size, location and
performance of facilities and equipment, for which the cost could
be calculated, is usually well beyond manual techniques. If
the costs were to be studied over the life of the facilities,
the various influential trends could be superimposed on all the
alternatives. The modern high speed computer could dispose of
hundreds of alternatives in minutes, contrasted to years of hand
-17-
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calculation. Additional information must be provided to the
system for this technique to be applied. Unit cost factors,
weighed against facility capacity and predicted trends, must be
available as basic information. This objective makes the infor-
mation system a true management tool, and makes sophisticated
optimization techniques available to all users.
2. e. PROVIDE_THE MEANS, TO DEVELOP TIMETABLES FOR PLANNING THE
ACQUISITION OF SOLID WASTE FACILITIES
This objective applies the results which would accrue from the
achievement of Objectives a, b and c to the development of a
timing schedule for additional facilities to replace or reinforce
existing facilities.
2. f. PROVIDE THE MEANS FOR DECISION MAKERS TO REQUEST SPECIFIC INFOR-
MATION AND PLANNING SERVICES
Since it will not be possible to anticipate all of the planning
and information problems which may be encountered by the potential
users of an information system, an objective of flexibility is
necessary. The users should be able to request replies to their
own specific problems, without excessive delays.
2. g. PROVIDE THE MEANS TO OPTIMIZE DAY-TO-DAY OPERATIONS
The availability of a high speed digital computer offers the
possibility of the optimization of solid waste operations on a
day-to-day basis. A classic example is the optimum routing of
refuse collection truck fleets. It should be an objective of a
solid waste information system to provide the computer program to
achieve this type of optimization. The achievement of this
objective will not provide benefits as widely applicable as
those provided by the planning objectives already discussed,
and it will require a substantial data input from the user.
The objectives listed in the foregoing discussion may be categorized as
either "must" or "want" objectives. That is, some of the objectives are
so basic to the entire concept of an information system for solid waste,
that they must be achieved, while others are not as basic and although
one would want to achieve them, failure to do so would not involve
immediate rejection of a proposed system, as would be the case with
the "must" objectives. "Want" objectives, therefore, could be used to
provide a graduated yardstick for system evaluation, whereas the "must"
objectives provide a "go - no go" choice.
The following are the recommended "must" objectives for a solid waste
information system:
MUST OBJECTIVES
1. a. Provide the means to insure that adequate data for any selected
system will be collected.
-18-
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1. b. Provide the means to improve the quality of the information.
1. c. Provide the means to standardize the information collected.
2. a. Provide the means to develop predictions of trends in significant
solid waste parameters.
The following are recommended as the "want" objectives for a solid waste
information system:
WANT OBJECTIVES
1. c. Provide the means to make information more readily available.
1. e. Provide information in a convenient and readable format.
1. f. Serve as a data clearinghouse system.
2. b. Provide the means to predict the saturation of existing facilities.
2. c. Provide the means to predict required capacity of new facilities.
2. d. Provide the means to minimize the total cost of refuse collection
and disposal.
2. e. Provide the means to develop timetables for planning the acquisition
of solid waste activities.
2. f. Provide the means for decision makers to request specific
information and planning services.
2. g. Provide the means to optimize day-to-day operations.
C. ALTERNATE SYSTEMS
Certain of the objectives stated in the previous section have been
recommended as "must" objectives while others have been recommended in
a "want" or "less necessary" category. Various information system
concepts may be evolved to meet some or all of these objectives. A
number of potential systems are defined, and a list of potential inputs
and outputs is provided for each. This is followed by schematic block
diagrams for several of the systems. The extent to which the stated
objectives would be achieved by each system is discussed.
1. DESCRIPTION OF SYSTEMS
a. SYSTEM //I - DATA CLEARINGHOUSE (Figure 2)
The data clearinghouse service would make data more readily
available to decision makers. This would be accomplished by
means of literature and data survey activities reported through
a periodic newsletter, and by the publication of annual
-19-
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statistical data solicited from solid waste administrators and
operators.
There is much information of a non-statistical nature generated
in the solid waste field which is of interest to decision makers
in the field. Reports on research findings, data on standards
and regulations, information on Government grants, published
reports and articles of various types, academic theses, consultant
reports, data on pilot tests, etc., could all find many valuable
uses. Often little of this material reaches the audience who
could most benefit from it. Municipalities often cannot afford
to maintain a full time librarian to track down this type of
data, and even when they can, there is still much which escapes
notice, or is just not available or even publicized. Consultant
studies and surveys are a prime example of this.
There is also statistical data available from other Government
programs which is significant in the planning of solid waste
activities. Examples of this data are population trends, economic
trends, data from highway programs, data on industrial production
trends, etc. as available from the Bureau of the Census, the
U. S. Department of Agriculture, the U. S. Department of Trans-
portation, the Department of Commerce and the Public Health
Service. Although available on request, the existence of this
data is not always known, or if known, its significance may
not be realized.
If the information and data mentioned above were to be available
to a decision maker in its entirety, his task in extracting what
is useful to him would be monumental. In effect, supplying too
much data and in the wrong form is often as bad as supplying too
little. In either case, the user falls back on his intuition
or experience.
System #1 could provide a valuable service as a data clearing-
house, where much of the avaialble data is distilled and arranged
for ready use. In addition, the availability of certain reports,
theses, and articles could be made known through a periodic
"newsletter". This publication would not necessarily include
any data itself, but would summarize that which is available and
provide instructions as to how it might be obtained. A service
similar to this is provided by the U. S. Department of Agriculture
in their monthly "Statistical Summary" and their monthly "Check-
list of Reports". This service would require full time staff
members to monitor the literature and to prepare summaries.
There are, in addition, a number of cities and smaller municipalities
who do maintain records with regard to quantities of refuse
processed, rate at which land is utilized, performance of facilities,
costs, etc. This data could be of service to other communities
if it were made available. System #1 proposes that municipalities
be queried, by mail questionnaire, on any such data they may collect,
-20-
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SYSTEM #1
DATA CLEARING HOUSE
SERVICE
PARTICIPATING
MUNICIPALITY
GOVERNMENTAL
AGENCIES &
PROGRAMS
STATE AND
LOCAL REGULATORY
BODIES
PUBLICATIONS,
CONSULTANTS,
TRADE' ASSOCIATIONS
UNIVERSITIES,
RESEARCH INSTITUTES,
GRANT PROGRAMS
Replies to Requests
Requests for_Information
Data Questionnaire
Returned Questionnaire
Data on Population, Economics, etc.
Other Non^-Quantitative Data
Data on'Standards & Regulations
Published Information,
Consultants Reports, etc.
Data on New Findings, R&D Results, etc.
ADMINISTRATIVE
GROUP
Inputs for Processing
Administrative
Review of Output
DATA
CLEARING HOUSE
SERVICE
Annual Data Service
to All Municipalities
General Information Dissemination
Monthly "Newsletter" to all Municipalities
Figure 2
Requests
Replies
Non-Quantitative Data
(Literature Information, etc.)
Quantitative Data
Feedback, Contact, or
Liaison Within System
-21-
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Those that participate will be asked to report on a specific
format, and will be asked certain questions to ascertain the
extent of measurements actually taken, what is included in the
costs reported, etc. The participation would be voluntary and
no field verification is contemplated. The data collected would
be subjected to a minimum of processing including some minor
calculations and rearrangement to provide information on a unit
(per capita, per ton, etc.) basis. The output would be reported
only for the contributing municipalities, but would be sent to
all municipalities above a certain population size.
In addition to the data collected in this manner, certain
statistical data might become available which could be of more
use to solid waste decision makers if'it were rearranged, expanded
or condensed. Often this data is available on cards or tape,
and the administrative group could program the system's computer
to recompile it.
System #1 would also be set up to reply to specific requests
regarding the availability of certain types of data. It is not
intended that copies of all available data be stockpiled, but
that the user is referred to the data's issuing agency from whom
he could request it directly. If he has difficulty in this, the
service could assist him.
b. SYSTEM // 2 - PREDICTIVE INFORMATION SERVICE (Figure 3)
The predictive information service would provide standardized
trend predictions of significant solid waste parameters to all
solid waste decision makers. These predictions would be based
on verified data gathered from a number of cities which would
be established as data gathering centers. These cities would
be selected in size, location and other characteristics to be
statistically representative of large regions of the country and
in this report are called "sample cities".
The output would be in the form of predictions as to the change
with time of such parameters as population, per capita generation
of refuse, refuse density and compactibility, refuse composition;
i.e., whether residential, commercial or industrial, bulky
versus mixed or combustible versus non-combustible, costs of
refuse operations per ton of material collected, disposed, etc,
This information would be reported in a standardized fashion on
the basis of data gathered at "sample cities" data sources.
The "sample cities" would be statistically selected in several
significant regions of the country. Statistical techniques would
be used to establish the number and location of such cities to
assure that a representative sampling is achieved. In these
cities, data gathering and reporting would be closely^controlled
to assure that all refuse is weighed, all dispositions, both
public and private are accounted for, all costs are reported and
-22-
-------
standardized, etc. The performance of collection and disposal
equipment would be carefully recorded and reported. Measurements
of land fill consumption, refuse density and compactibility,
incinerator residue density, etc. would be accomplished on a
regular controlled basis. The effects of .seasonal variations
would be clearly determined.
Each
-------
SYSTEM #2
PREDICTIVE INFORMATION
SERVICE
Admin
Reports
SEES' ---- °*s '
*
Assignments,
1 ! 1
i !
rnnti-ni Validation &
istration 1 Control
1 ! « of Data
i i i
"SAMPLE CITY"
DATA SOURCE
(Facilities, etc.)
REQUESTING
MUNICIPALITY
GOVERNMENTA L
AGENCIES &
PROGRAMS
DATA Basic
^ GATHERING Data ^
CONTROL
SYSTEM
Requests for Individual Predictions
Replies to Requests
Data on Population, Economics, etc.
ADMINISTRATIVE
GROUP
Administrative
Review of Output
Data Validation
Inputs
For Processing
PREDICTIVE
INFORMATION
SERVICE
~1
1
1
1
1
1
' fc
1
I
1
1
1
Requests
Replies
Non- Quantitative Data
Trend Predictions to Specific,
Qualified Requestors
Output of Standardized Trend Predictions
to all Municipalities, States, Regional
Jurisdictions, and Federal Government
(Literature Information, etc.)
Quantitative Data
Feedback, Contact, or
Liaison Within System
Figure 3
-24-
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Cities other than the "sample cities" could submit their historical
data for the purpose of having their own predictions developed.
This will encourage the improvement of data gathering and recording
activities on the part of all municipalities. However, many
cities do not usually exert the necessary control over their
refuse activities and record keeping, as compared to the "sample
cities". This individual prediction service would, therefore,
be offered only to those municipalities where satisfactory data
gathering and record keeping has been instituted.
c. SYSTEM #3 - PLANNING INFORMATION SERVICE (Figure 4)
The planning information service would provide computer based
mathematical models which could be applied to solid waste planning
and decision making activities. The service would be available
on a request basis. The models would be of a standardized
format, and requests would be adjusted to fit the models.
Computer programs would be created and maintained for the specific
purposes of providing communities with planning tools for solid
waste decisions which would not normally be available to them.
The requesting communities would supply certain basic data such
as number, capacity and location of current facilities, equip-
ment, land fill sites, etc., number, location and size of potential
land fill sites, and their likelihood of being put to this use,
etc. These data would be applied to standard computer programs
to assist the requesting community in locating and sizing new
facilities, equipment and land, for minimum overall collection
and disposal costs. The standard programs would be designed for
a minimum adaptation of input data for application to any
community's problem.
Many solid waste decisions require the consideration of large
numbers of alternatives. A good example is the situation where
several sites for a disposal facility are available. The decision
maker wishes to know what type facility he should consider,
what capacity, where to place it (or them), etc. so that he may
achieve minimum cost. He may wish to minimize the overall
collection and disposal costs not only for the immediate future,
but perhaps for a ten year period.
He requires knowledge of the trends of significant parameters,
including costs, population trends, population density trends,
distances for hauling, etc. Some of this he provides himself,
and some of it is made available by the system. The trend
predictions provided by this system would be based on a relatively
non-controlled collection of available data rather than on
controlled data from sample cities such as in System #2. As
such, the trend prediction results would be less accurate than
those resulting from System #2.
-25-
-------
Even with all the information in hand, the decision maker would
still be faced with the possibility of dozens of separate
alternatives whose cost must be calculated. Often the cal-
culations are of a trial and error nature, and the total number
of calculation cases reach unreasonable proportions. Without
high speed calculation*al assistance, the decision maker's
intuition and prejudice would take over to reduce the problem to
more manageable proportions. This is likely to result in costs
higher than they need be, and with location and type of
facility inconsistent with future needs. It is not intended to
belittle the excellent intuitive ability of certain decision
makers who can often correctly select among many alternatives.
This individual, unfortunately, is the exception, and the majority
could use assistance. A standardized program to accomplish
planning optimizations of the type described is considered
feasible. This has been demonstrated to some extent.1> 2
If a community provides only the basic data as to the current
capacity of incineration facilities and the life of land disposal
sites, System #3 would be capable, with the trend predictions,
of developing timetables which indicate when current facilities
will be saturated and recommending the size and timing of new
facilities.
In addition to planning optimizations as described above,
optimization of certain day-to-day operations would sometimes
be possible by means of high speed computations. The
optimization of a collection system routing has been attempted^
and further demonstration of the technique is planned. A
standardized program could probably be made available in this
area also.
The response to specific user requests, not applicable to the
previously described standard programs, but involving the
manipulation of basic information available within the system
would be within the capabilities of the system. A program would
be available which can readily call on the information within
the system, and arrange it in virtually any format requested.
Thus, a specific request, coded for processing, would be matched
against this general program. If the basic factors of the
question are within the scope of the program, it would be
answered. If not, the question would be returned with suggestions
for revisions which will make it match.
The standard programs described for System #3 would not be
available for use on individual computers. Instead, users would
query the system, and the programs would be applied at the
appropriate regional center. Duplicates of replies to queries
would be made available to regional planning agencies, state
agencies and the Federal Solid Waste Program. Thus, the using
municipalities' activities with regard to solid waste planning
would be monitored, at least to the extent that they request
-26-
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SYSTEM #3
PLANNING INFORMATION
SERVICE
PARTICIPATING
MUNICIPALITY
REQUESTING
MUNICIPALITY
GOVERNMENTAL
AGENCIES &
PROGRAMS
Data Questionnaire
Returned Questionnaire ^
Request for
Planning Services
Replies to Requests or
Instructions to
Adjust Requests
or to Provide
Data on Population, Economics, etc.
^
Other Non-Quantitative Data
ADMINISTRATIVE
GROUP
Inputs for
Processing
fr
^
Requests - Also
A dm inistrative
Review of Output
PLANNING
INFORMATION
SERVICE
*
^
»
~
^
Program for
Facility
Time Tables
Program for
Planning
Optimizations
Program for
/~*« + i
Optimizations
Program for
Requests
k
*
Output to Municipalities
Providing Basic Data
on Existing Facilities
Outputs
Replying to
Specific Requests
All Outputs are
Provided to
Regional, State
and Federal
Agencies involved
in Solid Waste
Acitivities
Requests
Replies
Non-Quantitative Data
(Literature Information, etc.)
Quantitative Data
Feedback, Contact, or
Liaison Within System
Figure 4
-------
services. Should a grant program for solid waste facilities
be instituted, the use of these planning aids could be made
mandatory for qualification.
Administration of this system would primarily involve the
monitoring of incoming requests and their preparation for
processing. Incoming requests may require adjustment before
processing and the computer output would be reviewed prior to
return to the requestor. Other functions of the administrative
group would involve the solicitation and processing of data
from municipalities who now collect such data, and the maintenance
and improvement of the computer programs.
d. SYSTEM #4 - PREDICTIVE AND PLANNING INFORMATION SERVICE
This system would combine the features of Systems //2 and #3.
Since System #2 would provide predictions of trends on a controlled
statistical basis; there would be no need for the unverified
questionnaire approach to gathering data for trend predictions
associated with System #3. In combining the features of Systems
#2 and #3, System #4 would achieve more of the objectives than
either of the other two individually.
e. SYSTEM it5 - DATA CLEARINGHOUSE AND PREDICTIVE INFORMATION SERVICE
This system would combine the features of Systems #1 and #2.
Since System #2 would provide predictions of trends on a controlled
statistical basis, there would be no need for the unverified
questionnaire approach to gathering data incorporated in
System #1.
f. SYSTEM #6 - DATA CLEARINGHOUSE AND PLANNING INFORMATION SERVICE
The data clearinghouse and planning information service would com-
bine the features of Systems #1 and #3. All data pertinent to solid
waste activities would be provided, along with computer based
mathematical models for solid waste decision making activities
on a request basis.
g. SYSTEM #7 - PREDICTIVE AND PLANNING INFORMATION SERVICE WITH DATA
CLEARINGHOUSE (Figure 5)
The predictive a'nd planning information service with data
clearinghouse would combine the features of Systems #1, #2 and
#3. All data pertinent to solid waste activities would be
provided. Standardized predictions of solid waste parameters
would be made available to all solid waste decision makers, and
computer based mathematical models would be applied to planning
and decision making activities on a request basis.
-28-
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SYSTEM #7
PREDICTIVE & PLANNING
INFORMATION SERVICE
WITH DATA CLEARING HOUSE
Admin
-2Z- -PECTORS
!
| i ! Vali
1 Control i Qua
Reports
Aw v» «»._ _«^_
Assignments,
etc.
dation and
lification
I J | of Data
i * !
i i i
"SAMPLE CITY"
DATA SOURCE
(Faciliti5s, etc.)
REQUESTING
MUNICIPALITY
GOVERNMENTAL
AGENCIES &
PROGRAMS
STATE AND
LOCAL REGULATORY
BODIES
PUBLICATIONS,
CONSULTANTS,
TRADE ASSOCIATIONS
UNIVERSITIES,
RESEARCH INSTITUTES,
GRANT PROGRAMS
Data
Gathering
Control
System
Basic
Data
Requests for Information or Services
fe
Replies to Requests or
Instructions
to Adjust Requests or
to Provide further Information
Data on Population, Economics, etc.
Other Non-Quantitative Data
Data on Standards and
Regulations
Published Information, Consultants Reports, etc.
Data on New Findings, R&D Results, etc.
ADMINISTRATIVE
GROUP
Figure 5
Administrative 1
Review of Output i
Data Validation
Inputs for
Processing
)
Inputs for
Processing
Feedback to Adjust
Requests, Also Adn
Review of Output
Inputs for
Processing
\
PREDICTIVE
INFORMATION
SERVICE
1 1
Trend Predictions to Specific,
J Qualified Requestors
i
!
i
Output of Standardized Trend Predictions
Jurisdictions, and Federal Government
PLANNING
INFORMATION
SERVICE
!
i
linistrative
DATA
SERVICE
i Program for Output to Municipalities "^
* Time Tables on Existing Facilities
lt .
Program for .j ^ *
» _, . -x provided to
» OpLizatfons * ] Hegiona.. State
» "I ^* , I vutPuts involved in
fc "r1:: , ' * > ucpiymgto Solid Waste
* Optimizations Specific Requests flr"v*t1
^ Program for
N«n-,Stanrtard .......... .,__^
* Requests J
General Information
to all Municipalities
eque
Non-Quantitative Data
(Literature Information, etc.)
Feedback, Contact, or
Liaison Within System
-------
2. SYSTEM INPUTS AND OUTPUTS
The effective operation of an information system is largely dependent
upon the inputs fed into the system and on the outputs which the
system will generate. The basic objectives of a solid waste infor-
mation system involve improvements in information (data) inputs and
the development of outputs useful for planning and decision making
purposes.
The inputs would be obtained from participating cities in a region
and from other available sources concerned with solid waste. In
addition, certain factors, necessary for the development of desired
outputs, which may not be directly involved with operation of solid
waste facilities, would also be obtained. ,In the development of
trend projections for entire regions, the required data may be
obtained from statistically selected sample cities.
S ystem outputs should be designed to be generally useful to many
cities and to be specific for cities facing a potential or actual
solid waste problem. The outputs should include not only general
solid waste related trends, but also should include specific planning
or decision making criteria required by the requesting cities.
a. INPUTS
The inputs to a solid waste information system could be categorized
under two broad areas.
(1) OPERATIONAL DATA - related to the collection, handling and
disposal of solid waste.
(2) PLANNING DATA - related to the planning and decision making
in solid waste management.
Operational data is that data concerning the amounts of refuse
collected and the conduct of the collection, storage and
disposal functions. Table I provides examples of operational
input data, and serves to further define the systems described
previously.
Planning data is that data which will have an effect on the solid
waste management function, but which is not directly involved
in the operation of facilities and equipment. Table II provides
examples of inputs and outputs for the systems described
previously.
b. OUTPUTS
The outputs of a solid waste information system must serve a
number of specific decision making needs to be useful for solid
waste management planning and decision making. Table III provides
examples of output information and indicates which of the systems
described previously would provide the outputs listed.
-30-
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TABLE I
OPERATIONAL DATA INPUTS FOR
SOLID WASTE INFORMATION SYSTEMS
Data Category
Quantity and Composition
of Refuse
Source of Refuse
Data Item
Refuse collected, by weight
Refuse incinerated, by weight
Refuse land filled, by volume
Percent combustible
Percent non-combustible
Density of combustible refuse
Density of non-combustible
refuse
Composition of combustible
refuse
Composition of non-combustible
refuse
Quantity of incinerator ash,
by volume
Quantity of incinerator ash,
by weight
Disposition of incinerator ash
Composition of incinerator ash
Rate of decomposition in land fill's
Municipal, percent by weight
Commercial, percent by weight
Industrial, percent by weight
Applicable
Systems
#2, 4, 5, 7
-31-
-------
TABLE I. Cont.
Collection of Refuse
Municipal tons collected by city
Municipal tons collected by
private collectors
Commercial tons collected by city
Commercial tons collected by
private collector
Industrial tons collected by city
Industrial tons collected by
private collectors
City collection facilities,
number and size of trucks
#2, 4, 5, 7
Cost of Collection,
City
Average distance hauled
Equipment operating cost
Manpower cost
Average frequency of collection
Disposal of Refuse
Land fill volume
Number and size of land fill sites
Incineration capacity
Number of incinerators and
capacity
Number of furnaces and capacity
Breakdown of land fill disposal,
by volume, by source and by
collection
Breakdown of incinerator disposal
by weight, by source and by
collection
Other disposal methods used
Weight and/or volume disposed
by other methods
-32-
-------
TABLE I, Cont.
Cost of Disposal
Operating Schedules
Cost per ton incinerated
Cost per ton land filled
Cost per cubic yard land filled
Equipment operating cost
Manpower cost
Factors included in cost figures
Number of days of collections per week
Number of hours per day of collections
Number of days of incinerator
operation per week
Number of hours per day of
incinerator operation
Operating time of incinerator at
various percentages of full load
#2, 4, 5, 7
-33-
-------
Data Category
Population
Land Availability
Local and State
Regulations
TABLE II
PLANNING DATA INPUTS FOR
SOLID WASTE INFORMATION SYSTEMS
Data Item
Residential population
Population density
Population area
Commercial population
Industrial population
Population growth trends
Income levels by groups
Present acreage owned by city
suitable for land fill use
Potential acreage for land fill use
Water table information
Stream locations
Zoning regulations
Location of potential land fill
acreage
Distance of potential land fill
acreage from city center
Distance of potential land fill
acreage from population, industrial
and commercial centers
Land prices and price trends
Solid waste disposal laws
Air pollution control regulations
Applicable
Systems
#2, 4, 5, 7
#3, 6, 7
#2, 3, 4, 5, 6, 7
#1, 7
-34-
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TABLE III
TYPICAL OUTPUTS OF
SOLID WASTE INFORMATION SYSTEMS
Trend Projections
Population versus year
Per capita generation of combustible
refuse versus year
Per capita generation of non-
combustible refuse versus year
Percent of combustible refuse col-
lected by city versus year
Percent of non-combustible refuse
collected by city versus year
Percent of combustible refuse col-
lected privately versus year
Percent of non-combustible refuse
collected privately versus year
Density factors versus year
Refuse composition versus year
Land fill availability (life) versus
year
Incinerator use availability (capacity
tons) versus year
Actual incinerator use versus year
#2, 4, 5, 7
Land Requirements
and Availability
Regional land availability for #3, 6, 7
disposal use
Regional net land deficiencies for "
disposal use
Capacity of each land fill site in "
terms of population served and for how
long
-35-
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TABLE III. Cont.
Land Requirements
and Availability
Remaining life of land fill sites #3, 6, 7
Inventory of land available for "
disposal
Standards and regulations affecting #1, 7
use of site for land fill disposal
Effects on land availability and life #3, 6, 7
of the use of incineration or other
disposal methods
Geography and water shed character- "
istics of available land fill sites
Population
Characteristics
Population growth trends
Population density factors
Percent population served by
facilities
Population income levels and effect
on waste generation (trends)
Commercial population location,
density and growth trends
Industrial population location,
density and growth trends
Areas of municipalities served by
facilities
All
All
#3, 6, 7
#2, 3, 4, 5,
6, 7
#3, 6, 7
Facilities Operation
Number and capacity of incinerators
in region
Standard per capita operating cost
of each incinerator in region
Percent of population served by
incineration
Percent of population served by land
fill
Collection systems used
#2, 4, 5, 7
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TABLE III. Cont.
Facilities Operation
Standard per capita operating cost
of municipal collection systems
Percent use factor of incinerators
in region
Performance characteristics of
facilities
Land fill operation reports,
monthly
Incinerator operation reports,
monthly
Age and condition of equipment at
each location
#2, 4, 5, 7
Research Results
Studies on waste composition
Studies on new disposal methods
Studies on the effects of various
factors on waste generation and
waste disposal
Studies on optimization methods
Studies of computer technology
application to solid waste management
Health and welfare effects of solid
waste management
#1, 7
Literature Availability
Literature available on all aspects
of solid waste generation and disposal
Planning Aids
Trend projections #2, 4, 5, 7
Needs projections #2, 3, 4, 5, 6, 7
Collection optimization studies #3, 6, 7
Disposal optimization studies "
Facilities location studies "
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TABLE III. Cont.
Planning Aids
Facilities needs recommendations #3, 6, 7
Timetables for facilities capacity "
saturation
Timetables for new facilities "
planning
Standards and
Regulations
Agency responsibilities for solid #1,
waste generation and disposal
Technical, procedural and financial
assistance availability from agencies
Acceptable standards for facilities
performance
Regulations regarding solid waste
collection, handling and disposal
Regulations regarding air, water and
land pollution
Sampling and testing regulations and
requirements
Federal controls (across state lines)
Design requirements for incinerators,
land fill and other disposal facilities
Disposal sites sanitary code
Land fill ordinances, pollution, burning,
zoning, vermin, penalties
Financing
Means of charging for refuse services
Magnitude of refuse charges
Means of financing new facilities
Investment required per population area
Opportunities for sale of waste products
Cost of capital
-38-
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3. ACHIEVEMENT OF OBJECTIVES
Table IV indicates how well each of the systems meet the objectives.
System #1 achieves very few of the objectives.
System #2 is seen to provide all of the "must" objectives. With
respect to "want" objectives, 2-b, 2-c and 2-e would be considered
"somewhat" achieved in that the trend predictions for key parameters
would permit the calculation of facilities saturation and needs
timetables on the part of individual decision makers. Although the
results of such individual calculations are likely to vary in con-
sistency and accuracy, the objective would be achieved to a slight
extent because the calculations would have been made on the basis
of better information than was previously available.
System #3 does not achieve any of the "must" objectives and, as
such, is inadequate by itself. Since System #3 would collect
available data in the manner of System #1, that is, without
statistical control or field verification, its achievement of
Objectives 1-a, 1-b, 1-c and 1-d would be similar to that of
System #1. However, since some trend predictions would be developed
to apply to the standard programs of System #3, Objective 2-a would
be partially achieved. Objectives 2-b, 2-c and 2-e would be partially
achieved in that trend predictions will be available, but since
they are not based on the "sample cities" approach, their accuracy
is limited.
System #4 would achieve all of the "must" objectives. Only the
objectives of providing the data clearinghouse and information which
is not now readily available would not be entirely achieved by
System #4. The latter would be partially achieved, but not all
information of interest would be provided.
System #5 would achieve all of the "must" objectives, and would
achieve Objectives 2-b, 2-c and 2-e somewhat in that the trend
predictions for key parameters would permit the calculation of
facilities saturation and needs timetables on the part of individual
decision makers. This would also be provided by System #2.
System #6 would not completely achieve any of the "must" objectives
and, as such, is inadequate by itself. The partial achievement
of Objectives 2-b, 2-c and 2-e would be based on predictions of
parameter trends not grounded in data obtained by statistically
controlled sample cities, but is based on unverified data only
from those cities who claim to collect it.
System #7 combines all features of Systems #1, #2 and #3, and would
satisfy all the system objectives. In combining the best features
of Systems #1 and #3 with the trend prediction features of System #2,
the need for the gathering of unverified data from solid waste
administrators and decision makers would be done away with. The
data would be entirely based on the "sample cities". The addition
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TABLE IV
ACHIEVEMENT
Recommended
Objective
Objective Category System 1
1-a
1-b
1-c
1-d
1-e
;i-f
2-a
2-b
2-c
2-d
2-e
2-f
2-g
Adequate Data "Must"
Quality of Information
Information More Readily Available
Standardize Information
Information in Convenient Format
Data Clearinghouse
Trend Predictions
Predict Facility Saturation
Predict Capacity Requirements
Minimize Cost
Predict Planning Timetables
Request Service
Optimize Operations
"Must"
"Want"
"Must"
"Want"
"Want1'
"Must"
"Want"
"Want"
"Want"
"Want"
"Want"
"Want"
No
Somewhat
Partially
Somewhat
Somewhat
Yes
No
No
No
No
No
Somewhat
No
OF OBJECTIVES
System 2
Yes
Yes
Partially
Yes
Partially
No
Yes
Somewhat
Somewhat
No
Somewhat
No
No
System 3
No
Somewhat
Somewhat
Somewhat
Yes
Somewhat
Partially
Partially
Partially
Yes
Partially
Yes
Yes
System 4
Yes
Yes
Partially
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
System 5
Yes
Yes
Partially
Yes
Partially
Yes
Yes
Somewhat
Somewhat
No
Somewhat
Somewhat
No
System 6
No
Somewhat
Partially
Somewhat
Yes
Yes
Partially
Partially
Partially
Yes
Partially
Yes
Yes
System 7
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
-------
of System #1, the data clearinghouse, provides general "state of
the-art" information in addition to the special planning and
decision making tools provided by Systems #2 and //3.
On the basis of meeting the most important or the "must" objectives,
the list of system alternatives can be reduced from seven to four.
The preferred systems are:
a. System #2 Predictive Information Service
b. System #4 Predictive and Planning Information Service
c. System #5 Data Clearinghouse and Predictive Information Service
d. System #7 Predictive and Planning Information Service with
Data Clearinghouse
D. EVALUATION OF SYSTEMS
Seven systems have been developed to meet all or part of the information
system objectives. These systems must be evaluated on the basis of
meeting the stated objectives, the estimated cost for operation of the
system and the benefits to be derived through use of the systems.
The results of these evaluations will provide the means for recommending
the best system for further consideration and possible implementation.
The cost of solid waste collection and disposal in the United States
has been estimated to range from $1.5 to $3.0 billion annually.5 Much
of this expenditure is not handled effectively, as has been indicated
by the lack of certain types of information and by the apparent
ineffectiveness of facilities, equipment and services for which the
money is spent. Better information and the better decision making tools
which can be derived from the information can be expected to help
expend the resources more effectively. From an economic point of view,
the question is straight-forward: "What will the better information
cost, and how much will it save?" The answer to the question is not
straight-forward. The benefits are difficult to quantify, and although
the costs are perhaps less difficult to estimate, they have, at this
conceptual state, a wide variability.
1. COST ESTIMATES FOR EACH ALTERNATIVE SYSTEM
Although four of the seven systems are preferred, the cost of each
of the seven systems is presented for completeness. The cost of
each system has been estimated on the basis of a ten year
operational period, based on separate estimates for first cost and
annual operating cost. Since estimates are based on preliminary
concepts, they exhibit a range of variation to account for the
uncertainties inherent at this stage. The results of the cost
estimates are shown on Table V. Details of the development of cost
estimates for each proposed system are given in Appendix B. The
cost estimates are based on certain assumptions concerning unit
costs for such items as keypunching, programming, data gathering,
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computer time, printing time, reproduction per page costs, etc.
These assumptions are also listed in Appendix B. Further assumptions
are developed within the estimates to indicate the limitations of
the activities described. It should be understood that the
estimates would change significantly if the assumptions and limitations
were changed.
Cost factors used include the following.
a. DATA GATHERING
Cost estimates for each of the systems are based on the accurate
and complete gathering of data at several selected localities
which can be used to statistically represent a large region com-
prising many times the area and population actually accounted
for by the "sample cities". The data gathering operation requires
the acquisition and operation of certain equipment in each of
these cities. This equipment includes:
Weighing scales and other measuring instrumentation, sampling
apparatus, etc. Equipment to determine refuse composition is
not included (see Appendix C).
Personnel are required to gather data, operate equipment, record
and tabulate data, inspect data gathering systems, etc.
Miscellaneous supplies, including paperwork and hardware are
also required.
The type of data to be gathered in the "sample cities" includes
all basic refuse tonnage and volume data as well as other refuse
and residue measurements, land fill consumption measurements, etc.
The number, location and other pertinent characteristics of the
"sample cities" are selected on the basis of the presumed sources
of variation of the quantities to be measured. If the number of
sources of variation leads to a large number of possible com-
binations, the "sample cities" are established by random selections.
The accumulation of data with time would allow the application
of multiple regression analysis on a time basis which would lead
to extrapolated predictions of trends in significant parameters.
A more detailed analysis is presented in Appendix D.
b. DATA PROCESSING
The data processing function includes the following cost factors:
Manual processing to prepare data for machine operation and to
screen out errors.
Keypunching and verification.
Conversion of cards to tape, screening of data and creation of
master file(s)-
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TABLE V
i
-C-
System
#1 Data Clearinghouse
Service
#2 Predictive Information
Service
#3 Planning Information
Service
#4 Predictive and
Planning Information
Service (#2 & #3 combined)
SUMMARY OF
(all cost
"Must"
Objectives
Totally
Achieved
None
All (4)
None
All (4)
SYSTEM COST
values shown
"Want"
Objectives
Totally
Achieved
1
None
4
7
ESTIMATES
are +20%)
First Cost
(First Year)
Cost
$ 225,000
1,600,000
360,000
1,860,000
Annual Ten Year
Cost Cost
$ 170,000 $ 1,755,000
1,000,000 10,600,000
212,000 2,270,000
1,134,000 12,066,000
#5 Data Clearinghouse and
Predictive Information
Service (#1 & #2 combined)
All (4)
1,713,000 1,095,000 11,568,000
#6 Data Clearinghouse and
Planning Information
Service (//I & #3 combined)
None
465,000
308,000 3,237,000
#7 Predictive and Planning Infor-
mation Service with Data Clear-
inghouse (#1, #2 & #3 combined)
All (4)
All (9)
1,940,000 1,220,000 12,920,000
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c. PROGRAMMING
Conversion programs to convert existing data.
Screening to assure data consistency.
File maintenance to enter new data.
Calculations to recompile data and to generate desired output.
Report generation to print output in desired format.
Systems analysis to conduct preliminary studies and to
assure information systems effectiveness.
Annual program modifications and eventual redesign.
Miscellaneous programs.
d. COMPUTATION
Program testing to "debug" programs.
Initial processing, calculation and report generation.
Annual processing, calculation and report generation to handle
annual as opposed to initial data load.
Printing of output for reproduction.
e. REPRODUCTION AND DISTRIBUTION
Reproduction for distribution to municipalities.
Mailing and handling.
f. ADMINISTRATIVE COSTS
Administrative personnel to supervise the operation.
Clerical assistance, i.e. secretaries, clerks, etc.
General supplies and equipment.
Although personnel costs are distributed throughout the various
cost factors as indicated above, the various personnel categories
which may be required for the information system are as follows:
a. Administrative personnel
b. Systems specialists
c. Systems assistants
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d. Programmers
e. Librarians
f. Keypunch operators
g« Secretaries
h. Clerks
2. EVALUATION OF BENEFITS
The benefits of each of the preferred systems must be defined and an
assessment made of whether there is basic economic justification
for the establishment of the information system. Many significant
benefits will result, but all of them are difficult to quantity.
There will be a gradual evolution of more and better information
for the planning and operation of solid waste activities, which will
result in a general up-grading of the "state-of-the-art" and in more
effective decisions over the long term. Expected benefits will be
listed and a broadly based analysis conducted to determine whether
the level of expenditure is justifiable in terms of benefits to the
users. Specific quantifying of benefits will then be attempted to
determine whether the added cost increment required to achieve all
objectives is justified.
a. BENEFITS
The benefits for Systems #2, 4, 5, and 7 are presented in terms
of their realization by the decision makers who would use the
system. The following is a list of benefits expected from the
information system. Following each benefit is the number of the
system which provides the benefit.
(1) The user would know what data is available and that he is
not missing anything significant - #5, #7.
(2) The user would obtain his needed data quickly, without
repeated inquiries - #4, #7.
(3) The user would have his needed data in ready-to-use form -
#2, #4, #5, #7.
(4) The user would know that the data is based on consistent
standards - #2, #4, #5, #7.
(5) The user would know that the data is representative of his
geographic region - //2, #4, #5, //7.
(6) The user would know that the data was developed on the
basis of proven and accepted techniques - #2, #4, #5, #7.
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(7) The user would be given the benefit of sophisticated
computer usage and techniques, regardless of his community's
size and means - #2, #4, #5, #7-
(8) The user would know with reasonable certainty whether his
future plans are sufficient and timely - #2, #4, #5, #7.
(9) The user would know that his plans and operations are as
optimum as modern management technology can make them -
#4, #7.
(10) The user would have available an information service from
which he could request assistance - #4, #7.
(11) The user would be likely to improve his own data gathering,
planning and operations as a result of the positive
influence of a well organized information system - #4, #7.
(12) The user would save money he would otherwise spend on
surveys which are often of questionable value - #4, #7.
(13) The user would save money because he can plan more quickly
and effectively - #4, #7.
(14) The user would save money because significant changes in
facilities and operations would be planned for well in
advance - #4, #7.
(15) The user would save money because he would have better
knowledge as to how well his money is being spent - #2,
#4, #5, #7.
BROAD ANALYSIS OF SYSTEM BENEFITS
(1) VALUE OF INFORMATION
According to the 1960 census, there are over 6,000 communities
above 2,500 population and of basically urban character.
Of these, approximately 270 operate incineration facilities
and can be assumed to also operate weighing scales to
obtain basic refuse tonnage data. If the presence of a
weighing scale is assumed to indicate that a limited
capability for accumulating data exists, then it is assumed
that these communities would not place any value on such
data developed elsewhere. Similar remarks apply to those
of the remaining 5,730 communities which operate weighing
scales at land fill sites. Data developed by means of a
statistically based information system can be expected
to be of some quantifiable value to the remaining communities.
Estimates of this value in terms of dollars per year,
multiplied by the number of cities, gives an indication of
an annual "value" of the information developed. Table VI
summarizes this calculation.
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TABLE VI
Community
Populations
1,000,000 and over
500,000 to 999,999
250,000 to 499,999
$ 100,000 to 249,999
i
50,000 to 99,999
25,000 to 49,999
10,000 to 24,999
5 ,000 to 9,999
2,500 to 4,999
Under 2,500 Urbanized
Urban Total
Number
In U.S.
1960+
5
16
30
81
201
432
1,134
1,394
2,152
596
6,041
CALCULATION
Number
Incinerating^
4
11
10
18
50
41
79*
56*
269
OF THE "VALUE" OF
Estimated Number
With Scales
at Land Fills3
1
5
10
30
40
20
10
0
0
0
BETTER INFORMATION
Number
Requiring
Data3
0
0
10
33
111
371
1,045
1,338
2,152
596
5,656
What Are They What Are They
Willing to Willing to
Pay ?/Year Pay?
(each) 3 (Total)3
$3,000 to $5,000 $30,000 to $50,000
$1,500 to $2,500 $49,500 to $82,500
$500 to $1,000 $55,000 to $111,000
$300 to $500 $111,000 to $186,000
$200 to $400 $209,000 to $418,000
$50 to $150 $67,000 to $201,000
$521,500 to $1,048,500
* Reference 5
1 1960 Census Data.
2 From results of Contract Ph 86-66-163 except as noted by asterisk.
3 Combustion Engineering, Inc. estimates.
-------
Thus, the estimated value of the information ranges from
approximately $500,000 to $1,000,000 per year, compared to
an average annual cost for System #7, of $1,300,000. This
rather simple and conservative calculation clearly shows
that the cost of the information provided is likely to be
largely offset by what the users might be willing to pay
for it if they had to buy it. Any benefits accruing from
the availability of the information are in addition to
this basic balance of "value" versus cost.
(2) EFFECT OF INFORMATION ON FUTURE FACILITIES
The estimated 1966 incineration capacity in the United States
is approximately 75,000 tons (per day). The results of
the mathematical analysis conducted under this program
indicate that in 1975, the capacity will increase to some-
where in the range of 108,000 to 125,000 tons, or there
will be an increase of 33,000 to 50,000 tons. If a typical
incineration plant is assumed to consist of two 250 ton
furnaces, then 66 to 100 new plants may be built by 1975.
If the unit cost of these plants is assumed to be $6,000
per ton, then the total cost per new plant would be
$3,000,000 and the total estimated investment in incineration
facilities between 1966 and 1975 would be $198,000,000
to $300,000,000.
If an information system is operative during this period,
and the objectives are achieved as stated, some portion of
the above investment may be saved, due to the availability
of better planning information and a general upgrading of
the "state-of-the-art". In addition, many surveys will
be made unnecessary and the moneys saved can be assigned
to more effective designs. The optimization of the number
and location of regional incinerators in given situations
can be expected to provide substantial long term savings.
It will be assumed that the aggregate of all potential
savings attributable to an information system will amount
to 5 percent of the above investment total. Thus, the
anticipated savings will range from $9,800,000 to
$15,000,000. These figures bracket the anticipated ten
year cost of System #7. This estimate of savings does
not account for any savings attributable to better
facilities decisions with regard to land fill operations,
nor does it consider any savings achieved in the operation of
facilities.
SELECTION OF BEST SYSTEM FOR MAXIMUM COST EFFECTIVENESS
System #2, the predictive information service, does not achieve
any of the "want" objectives, and as such it does not achieve
benefits 1, 2, 9, 10, 11, 12, 13 and 14 (Reference section 2-a).
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When Systems #2 and #3 are combined to make System #4, the added
cost increment (ten year total) is $1,400,000. This system does
not achieve benefit 1, but benefits 2, 9, 10, 11, 12, 13 and 14
are achieved at an additional cost of approximately $140,000
per year.
When Systems //I and #2 are combined to make System #5, the added
cost increment (ten year total) is $900,000, and it does not
achieve benefits 2, 9, 10, 11, 12, 13 and 14. Thus, the additional
cost of approximately $90,000 per year has achieved only the
additional benefit 1.
When all systems are combined, System #7 results, and it achieves
all the stated objectives and provides all the benefits. This
system requires an additional $2,225,000 over System #2 (ten
year total), or approximately $225,000 per year to achieve
Objectives 1, 2, 9, 10, 11, 12, 13 and 14.
Benefit 1 is provided by the data clearinghouse system (System #1)
which, when coupled with System #2 to make System #5, adds a
literature search and literature surveillance service; at a cost
of $90,000 per year. This amounts to about $16 per year for each
community assumed to need data. The potential benefits of
having all these communities receive the means to remain well
informed certainly is well worth this nominal cost.
Benefits 11, 12, 13 and 14 are those which deal with more timely
and effective planning and they are primarily achieved by System #3
acting in conjunction with #2 to make System #4. The potential
benefits of improved planning have already been quantified in a
broad sense in Section b-2. The addition of System #3 to #5, to
give #7, requires an additional $136,000 per year. This is again
a nominal cost for providing additional assurance that the data
to be gathered by System #2 is properly applied.
Thusj System #7 is recommended and provides the potential of
benefits whose estimated value substantially exceeds its cost.
E. SPECIFICATION FOR A PILOT SYSTEM
In order to demonstrate that the recommended system can be successfully
implemented, a pilot program is indicated. This pilot system should
encompass, on a smaller scale, all of the features of the full scale
System #7, which has been recommended for implementation, and upon
completion should be capable of virtually complete integration into the
overall system. The pilot system should encompass a sufficiently large
and representative region of the country and should contain certain
minimum historical and planned municipal solid waste activity. The
historical activity should be reasonably well documented, so that the
changing pattern of decision effectiveness may be assessed.
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1. OBJECTIVES OF PILOT SYSTEM
a. PROOF OF PROPOSED SYSTEMS AND TECHNIQUES
The pilot system should investigate proposed systems and techniques
in sufficient detail to prove out their feasibility and
practicability to a reasonable level of confidence. It should
also be capable of altering and developing proposed systems and
techniques until they are workable. In this sense, the pilot
system should also provide an R & D capability.
b. ESTABLISH OPERATIONAL FORMAT FOR FINAL SYSTEM
The pilot system should establish the degree of sub-division
required in an ultimate system. That is, the pilot system should
help decide whether the administration of the ultimate system
be centralized or distributed. The administrative center for
the pilot system should, therefore, either be considered the
prototype of several others, or possibly the nucleus of a
single center for the ultimate system.
c. ABSORPTION IN FINAL SYSTEM
The pilot system should be capable of absorption into a broader
nation-wide system with a minimum of alteration. Some "sample
cities" may have to be dropped. However, the cost of maintaining
these cities active should be carefully weighed against the
already expended cost of establishing them, and their continued
value in the system.
d. COMPATIBILITY WITH INFORMATION SYSTEM TECHNOLOGY
Information systems for municipal activities are receiving more
widespread attention. The pilot system for a solid waste infor-
mation system should attempt to function to the maximum possible
extent in cooperation with such efforts.
2. CHARACTERISTICS OF PILOT REGION
a. SIZE
A reasonably significant portion of the United States would be
a plausible size for the pilot system's area. One of the
Public Health Service's nine regions> preferably one with some
climatic variation within its boundaries, would be a
logical choice; however, the potential political difficulties
of operating in a multi-state area should be recognized and
dealt with at the outset.
b. POPULATION
Since the solid waste problem is most serious in areas of current
and expected high population density, the pilot region should be
one of the more populous regions of the country.
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c. ECONOMIC MAKE-UP
The pilot region should include areas of all economic ranges,
from relatively wealthy communities, to poor, or depressed
communities. Cities within the region should have similar
economic ranges within their own individual boundaries.
d. ZONING CHARACTERISTICS
The region should encompass communities of all types, including
residential, suburban communities and industrial urban communities.
The region should include at least one relatively large
metropolitan area, and several moderately large cities.
e. SOLID WASTE ACTIVITIES
The region should contain solid waste activities of all types,
from incineration and composting to land fills and modified land
fills, to open dumps. Collection activities by both private and
municipal agencies should be present. There should have been
relatively recent solid waste decisions of a significant nature,
with several additional decisions pending within a year or two.
Most of the cognizant state agencies should be active in solid
waste programs, and should be willing to participate in the
pilot program.
3. CHARACTERISTICS OF THE PILOT SYSTEM
a. SAMPLE CITIES
The region should include a sufficient number of sample cities to
assure a statistically valid sample. Wherever possible, existing
data-taking operations should be qualified to increase the number
of samples. The total for the pilot region should significantly
exceed the number of sample cities which would be allocated to
it if the nation-wide system were to be established all at once.
b. INPUTS AND OUTPUTS
Input data should be gathered on refuse quantities in weight and
volume units, on refuse disposition, on refuse generation by
economic areas and on rate of land consumption by land fill and
incinerator operations. Cost data should be accumulated, with
all cost elements included. Significant operational data on
collection should be gathered, such as haul distances, haul times,
number of stops, costs, etc.
Output information should be developed to provide trend predictions
in the significant solid waste parameters and to provide planning
recommendations applicable to specific planning situations as
may be encountered during pilot system operation.
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c. HISTORICAL DATA
Cities within the region should be asked to provide whatever
historical data is available. The administrative center would
scrutinize this for its utility and would base early system
output on it, while new data is accumulated.
d. COMPUTER PROGRAMS AND COMPUTER OPERATION
Since the pilot program may prove of a temporary nature, computer
programming and operation should be obtained through service
bureaus, of if possible, through the cooperation of one of the
participating states' EDP system, or at a university computer
center if it can accommodate the required load. All of the
complete and detailed programs called for by the recommended
system need not necessarily be developed. It may be possible
to develop brief programs tailored to specific decision situations
as they arise, and these programs would eventually be combined
to absorb all desirable features into a broader general program.
The request service program may not need to be developed, since
in the pilot program it is more likely that the administering
body must seek out situations to which they will apply the techniques
of the system.
e. ADMINISTRATIVE STAFF
A full administrative staff must be established at the outset,
including all inspection and other feedback features. This staff
would solicit initial cooperation with state and local officials
and would monitor the data gathering process. They would
administer whatever grant funds would be necessary to help
upgrade the data gathering capability of a given community.
The administrative staff would be responsible for periodic
status reports to assure that the continuation of the pilot
program was warranted.
f. DURATION OF PILOT PROGRAM
The pilot program would probably require one full year to become
operative, and an additional two to four years to develop
sufficient data to provide trend predictions. However, evaluation
of whether the system would be feasible for nation-wide application
could be accomplished earlier than this, if the system were
apparently operating successfully.
g. COST OF PILOT PROGRAM
The estimated cost of establishing the pilot program (also the
first year cost) is $419,000. The estimated annual operating
cost is $303,000. The total cost until integration into a
nation-wide system after an assumed four duration is $1,328,000.
The details of these cost estimates are given in Appendix B.
They have an anticipated range of variability of +20 percent.
-52-
-------
The estimated pilot system cost represents approximately
10 percent of the total system ten year cost.
-53-
-------
SECTION VI
REFERENCES
1. Baker, J. S, University of Maryland. A Cooperative Municipal Refuse
Disposal Program. Prince George's County, Maryland, 1963.
2. Baker, J. S. Finding the Lowest Cost for Refuse Disposal. Public
Works, Nov. 1963.
3. Quon, Charness and Wersan. Simulation and Analyses of a Refuse Col-
lection System. Journal of the Sanitary Engineering Division ASCE.
Oct. 1965.
4. Mann, W. J. The City of Raleigh is the Recipient of a Federal Grant.
5. APWA Research Foundation. Solid Wastes, The Job Ahead. APWA Reporter.
Aug. 1966.
6. Purdom, P- W. Characteristics of Incinerator Residue. 1966 Proceedings,
Comments by Dr. R. Braum and Dr. Ing. H. G. Kayser, Institute for
Solid Wastes.
7- Kaiser, E. R. Chemical Analyses of Refuse Components. Proceedings of
1966 National Incinerator Conference, ASMS.
8. Etzel, J. E and J. M. Bell. Methods of Sampling and Analyzing Refuse.
APWA Reporter, Nov. 1962.
9. Bell, J. M. Development of a Method for Sampling and Analyzing Refuse.
Ph.D. Thesis, Purdue, 1963.
-54-
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SECTION VII
APPENDIX A
QUESTIONNAIRE AND INTERVIEW PROGRAM
A. PURPOSE
1. A basic element of the solid waste information system study is the
determination of the type of information required by planners and
decision makers concerned with solid waste collection and disposal.
A further element is the determination of how much of this infor-
mation is readily available and what information is not now
available to these people. A mail questionnaire program was devised
as a means to survey the information needs and the information
availability. Those surveyed for this purpose were the planners
and decision makers who would actually have use for the information.
2. Another element of the solid waste information system study is the
determination of problems and practices involved in the use of
information systems by Governmental agencies. A questionnaire survey
was taken of the designers of Governmental information systems in
order to accomplish this.
3. Another purpose of the questionnaire surveys was to determine the
current information practices in the area of solid waste collection
and disposal. The practices considered to be important include
the sources of information and their reliability, methods of obtaining
the needed information, the cost of obtaining the information and
the usefulness of the information gathered.
4. In addition to the questionnaire surveys taken, twenty-one personal
interviews were conducted. These interviews were intended to obtain
a more detailed understanding of current information practices and
the problems in obtaining the needed information, to further assess
the need for and the possible nature of an information system, and
to confirm the questionnaire findings.
B. APPROACH
1. Two types of questionnaires were used for the information system
study. One was directed to those who would use the information for
planning and decision making purposes in their capacities as refuse
officials. This questionnaire (Questionnaire A at the end of this
appendix) contained questions concerning the type of information
required, the type of information normally obtained, the type of
information which has to be specially obtained, and the methods and
practices used in obtaining the special information. It also attempted
to define the specific nature of the information needed and the
reasons why some of this information cannot at present be readily
obtained.
-55-
-------
The recipients of this questionnaire were categorized by their
specific function and area of interest. This was done for several
reasons. First, it was necessary to insure that the responses
would be representative of a number of different viewpoints.
Categorization of the questionnaire addressees made possible the
development of a mailing list covering these different viewpoints.
Second, it was considered desirable to categorize the responses
received in order to define the various areas of decision concern
and to define the specific information required by each decision
area. The categories used for this questionnaire were concerned
with planning and other decision making activities in the refuse
field. They included the following:
a. State Planners (e.g., State Health Department)
b. Regional Planners (Where Regional Authorities exist)
c. Municipal Planners (e.g., Directors of Public Works)
d. Operators (Municipal, Regional, Private - e.g., Superintendent
of Sanitation)
e. Equipment Manufacturers (e.g., Incinerators, Packers)
f. Consultants (e.g., Planning and Design Consulting Engineers)
g. Researchers, Civic Groups and Others
No geographic preference was used in choosing the specific recipients
within each category. The discussion of results to follow will
cover the responses both by categories and as an aggregate.
The second questionnaire used was directed to those involved in the
design and application of information systems for Governmental use,
and where possible, with regard to refuse activities. This question-
naire (Questionnaire B at the end of this Appendix) included
questions concerning the areas of primary responsibility, methods
used for collection of data, handling and analyzing of data and
information, costs of information handling systems and usefulness
of the results obtained. It also attempted to define some of the
problems in utilizing Governmental information systems and some of
the specific information needs for these systems. The recipients
of this questionnaire were also categorized by their functional
areas of activity. Again, this was done to insure representative
responses from the various functional areas of interest, and to
determine any differences in needs from these areas. The mailing
list was made up on the basis of the following categories:
a. Federal Planners
b. State Planners
c. Consultant Planners
-56-
-------
d. Authors
e. Research Institute Planners
f . Trade Association Planners
g. Miscellaneous
Again, no geographic preference was used in choosing the specific
recipients within each of these categories. In the analysis of
responses to this questionnaire, it was found that too few responses
came from each individual category to allow valid conclusions to
be drawn on a category basis, nor did any significant differences
appear to exist between categories. The results to follow are
therefore presented on the basis of the aggregate response to this
questionnaire.
3. The interviews were also categorized in order to insure that the
results were representative of those areas considered of primary
importance with regard to refuse activities. Time and cost limited
the personal interviews to only a sampling in each category. These
categories- included:
a. State Planners
b. Municipal Planners
c. Regional Planners
d. Operators (Municipal and Private)
e. Consultants
f. Researchers
g. Equipment Manufacturers
C. RESULTS
1. RESPONSE
Response to the questionnaire mailing, both to "Refuse Officials'1
and "Data System Specialists", was quite good, with better than
one-third of the mailing returned as usable responses.
The following are the response statistics:
-57-
-------
a. "Refuse Official" Questionnaire (Questionnaire samples at end
of this appendix)
198 sent 73 usable responses
Category - State Planners
13 sent 9 usable responses
Category - Regional Planners
12 sent 5 usable responses
Category - Municipal Planners
53 sent 21 usable responses
Category - Operators
49 sent 13 usable responses
Category - Manufacturers
24 sent 4 usable responses
Category - Consultants
24 sent 14 usable responses
37 percent
70 percent
42 percent
40 percent
27 percent
17 percent
58 percent
Category - Researchers» Authors and Miscellaneous
23 sent 7 usable responses 30 percent
"Data Systems Specialists" Questionnaire (Questionnaire samples
at end of this appendix)
68 sent
27 usable responses
40 percent
Although various categories were used in developing a mailing
list for the "Data System Specialists" questionnaire, it was not
considered significant to report the response in accordance with
these categories, especially since the number of respondents in
most of them is too small to draw any meaningful categorized
conclusions.
A copy of the "compilation questionnaire'' for each type of question-
naire is included at the end of this appendix. This will permit
the reader to examine in detail the aggregate response to each
question. The discussion to follow will delve into the significance
of these responses, particularly for the "Refuse Official" question-
naire, where response by category is most pertinent to the feasibility
and design of an information system for municipal refuse.
-58-
-------
2. DISCUSSION OF THE "REFUSE OFFICIALS" QUESTIONNAIRE
QUESTION l(b)
This question asked the respondents to rate their primary decision
areas. The results of this rating are presented on Figure 6.
This chart clearly shows that the majority of the categories consider
long range planning as their primary decision area. Only operators
of refuse facilities and state planners did not choose long range
planning as either a first or second choice. The second choice,
in the aggregate, was "the evaluation of performance of refuse
facilities". The third choice was "the evaluation of effectiveness
of plans".
QUESTION 2(a)
Figure 7 illustrates the type of data that is normally obtained by
each of the "Refuse Official" categories. The results are presented
on the basis of percent of each category responding. The chart
emphasizes those cases where more than 50 percent of the respondents
in a category nromally obtain the type of data indicated. The chart
shows that data on facilities performance, refuse quantity,
population and costs of refuse activities can be considered normally
obtained by most of the categories.
QUESTION 2(b)
Figure 8 illustrates the type of data that is considered important
in decision making by each of the "Refuse Official" categories.
The chart shows that data on land requirements, facilities performance,
refuse quantity, and costs of refuse activities can be considered
as most important. Comparison with Figure 7 shows that data on
land requirements is important, but generally lacking.
QUESTION 3(a)
Figure 9 illustrates the type of data that has had to be specially
obtained by each of the "Refuse Official" categories. The chart is
arranged to emphasize those cases where more than 33 percent of the
respondents in a category had to take special steps to obtain the
type of data indicated. As expected, data on land requirements
frequently had to be specially obtained. But, in addition, data
which was normally obtained, such as facilities performance, refuse
quantity, and costs of refuse activities, was also quite frequently
specially obtained. This indicates that normally obtained data is
probably often insufficient or incomplete for the decision required.
Comparison of Figures 8 and 9 also indicates a few areas where data
was not considered important, but has been obtained specially.
Examples are data on air pollution, refuse composition, and
population. These will probably become more important with time.
-59-
-------
PRIMARY DECISION AREAS OF "REFUSE OFFICIALS"
1 - First Importance
2 - Second Importance
3 - Third Importance
Categories
Long Range
Planning
Obtaining
Public
Support
Evaluating
Effectiveness
of Plans
Establishing
Standards &
Operation
of Refuse
Facilities
Regulations & Equipment
Evaluation of
Performance
of Refuse
Facilities
o
I
State Planners
Regional Planners
Municipal Planners
Operators
Manufacturers
Consultants
Researchers ,
Authors & Misc.
1
1
3
1
1
2
2
2
3
3
2
3
3
2
1
3
1
1
2
2
3
Figure 6
-------
INFORMATION NORMALLY OBTAINED BY "REFUSE OFFICIALS"
Refuse
Quantity
Refuse
Composition
Population
Costs
of Refuse
Activities
State Planners
(9 Replies)
45%
22%
?T.78%
45%
Regional Planners
(5 Replies)
40%
40%
Municipal Planners
(21 Replies)
14%
47%
Operators
(13 Replies)
30%
38%
'92% t
Manufacturers
(4 Replies)
, .50%
Consultants
(14 Replies)
y/
85% '
78% ..'
Researchers & Misc.
(7 Replies)
43%
29%
29%
Aggregate
(73 Replies)
45%
34%
y///
''''' 66%
Percents shown are percent of each category which normally obtains the particular class of information.
For example, 90 percent of the twenty-one municipal planners normally obtain refuse quantity information.
Figure 7
-------
INFORMATION.CONSIDERED IMPORTANT IN DECISION MAKING BY "REFUSE OFFICIALS"
Land
Requirements
Facilities
Performance
Equipment
Inventory
Air
Pollution
Refuse
Quantity
Refuse
Composition
Population
Costs
of Refuse
Activities
State Planners
C9 Replies)
45%
22%
45%
45%
Regional Planners
(5 Replies)
20%
' S.
Municipal Planners
(21 Replies)
14%
38%
28%
Operators
(13 Replies)
30%
£ 53% 4' .,/
46%
38%
30%
-'84%
? '
Manufacturers
(4 Replies)
0%
25%
0%
. .
. 50%
":. '50%
Consultants
(14 Replies)
i''.;/ 50%
14%
57% .
,
-.. '487 ^'"r^
./,/ '°*f?£-Tt -:f-;f.
"
*<*
Researchers & Misc.
(7 Replies)
43%
43%
-
r-f
--- 7 '
.-11%--
Aggregate
(73 Replies)
27%
44%
47%
48%
73%.
Percents shown are percent of each category which considers the particular class of information aa important.
Figure 8
-------
INFORMATION SPECIALLY OBTAINED BY "REFUSE OFFICIALS"
Land
Requirements
Facilities
Performance
Equipment
Inventory
Air
Pollution
Refuse
Quantity
Refuse
Composition
Population
Costs
of Refuse
Activities
State Planners
(9 Replies)
Regional Planners
(5 Replies)
0%
20%
20%
Municipal Planners
(21 Replies)
28%
14%
'> 33%'
19%
14%
Operators
(13 Replies)
7%
30Z
7%
15%
&
Manufacturers
(4 Replies)
0%
25%
25%
50%
"'50%'
25%
Consultants
(14 Replies)
7%
,-'
"tV/1 : 42%
7%
42%
57%
28%
21%
Researchers & Misc.
(7 Replies)
14%
29%
712
43%.
0%
Aggregate
(73 Replies)
16%
377
49%
27%
22%
Percents shown sre percent of each category which had to obtain the particular information by special means.
Figure 9
-------
Figure 10 shows the percentage of respondents in each category who
had to obtain special data in areas where they already received
data normally. This clearly shows where the normally obtained
data required extension or refinement. Refuse quantity data and
cost of refuse activities data exhibited this characteristic in almost
all categories of decision makers.
Figure 11 provides a semi-quantitative illustration of the apparent
data deficiency. Where a category of decision maker considers a
particular data item important, and has also had to obtain special
data in that area, that box in the matrix is darkly shaded to
indicate a strong data need. Where the decision maker considers the
data important but appears to have adequate data available, the
box is lightly shaded, indicating a potential data need. Where the
decision maker did not consider the data area as important to his
decision making responsibility, but then indicated that he had to
obtain special data in that area, the matrix is marked with an
"X". In general, the areas of information need are in land require-
ments, facilities performance, refuse quantity and costs of refuse
activities. Refuse composition and population information are
considered important, but adequate data for present needs is
apparently available. Air pollution was not considered overly
important except by regional planners, manufacturers and consultants.
QUESTIONS 3(b) AND 3(c)
Figure 12 graphically illustrates the aggregate response of the
"Refuse Officials" to questions dealing with the specially obtained
data. Only the aggregate response is presented because it was not
considered that the response by category would be significant.
Figure 12 gives the percent response as to the staff used, the method
of collection, and the cost for obtaining the special data.
Eighty percent of the "Refuse Officials" had to obtain additional
special data during the past year. They primarily used their own
staffs, and they used interviews, direct measurements and their
own records as the means for collecting the required data. Their
estimates of the cost varied from under $200 to over $5,000 with no
range strongly emphasized. Some may have included the costs of using
their own staff and some not. Approximately 50 percent of those who
obtained special data in the last year estimated that the cost was
in excess of $1,000.
QUESTION 3(d)
Figure 13 summarizes the respondents' opinions about the usefulness
of the special data. The primary usefulness was in "providing a
more accurate basis for decisions". Only manufacturers and con-
sultants did not give this their first vote. These rated "more
accurate design of facilities" as first choice. In the aggregate,
this latter was second, and "improved services'! was third choice.
The speed with which a decision is made seems to be of little concern
-64-
-------
INFORMATION BOTH NORMALLY AND SPECIALLY OBTAINED BY "REFUSE OFFICIALS"
State Planners
(9 Replies)
Regional Planners
(5 Replies)
(21 Replies)
Operators
(13 Replies)
Manufacturers
(4 Replies)
Consultants
(14 Replies)
Researchers & Misc.
(7 Replies)
Aggregate
(73 Replies)
Land
Requirements
SXjtf-j^^j-'j'-vj1.^. * "/y
Wtr, d£jip$9&?~" /*"-, S
^^^&.
19%
15%
0%
0%
14%
18%
Facilities
Performance
!".U , ^Jf^-yt V y£'J "^l--*-.
IP*I
^jt'Sf^/fr- «'*-' '«. ffrii
0%
28%
30%
0%
28%
14%
26%
Equipment
Inventory
11%
0%
9%
7%
25%
0%
14%
7%
Air
Pollution
F^i'j" £frVS,j' "-''.'.r^?''Xf^
K^il
''^fi'1' <,Vt9%?Sfe'J''' ''
23%
23%
25%
35%
14%
27%
Refuse
Quantity
'.',-. -.4^,'-^';' ' ^
^ j/*" '- '^' '
j-^ ,^'' *"OQ%>- -' " "y^
,'. ^fyt1-'1'- j-:; ./^j§i
20%
^^^^^
fe£:!'..i
.-'- '^iK'-.fjr- ' ':"' 'r
f^:f-
'-' - .' -"-- -
§S?;f
'#;'-*//'? <:$£,
fM^--- ^'^
fj.~y A3% -
"' -';:". '/ '-:?-:i. '' '^
"''>:'- -' .'-tfi"- ' v
^§;;;/;::;^-'-.:-v
f^:'4°*.- '--' "
Refuse
Composition
11%
20%
0%
0%
^50%^";^;'.'.-^
pj..'-.^3^!-^Vvr,-.^
21%
14%
11%
Population
J*ty.*~*--- ~~s* l'~'
W*?$i
s' -: ''--'-;: ' - :-**S ' '"
f ^-' ' '-; - - ' -,
9%
7%
25%
14%
0%
18%
Costs
of Refuse
Activities
jf X f-- -£t( - f
; , - >t ' ' _. ~~- r j *'
' !'' f~ V*iy ' ' , '^ '
' - *",*$» -'' \-f6
0%
l?:' ' :H"" f-
>-' - 6 1%
IT"* ' ' - '.'
' ' " -*
"' """ ' " ;'
"* //-i'>- ~~''>
3?"%- -' ^^y - "'--' ^ J
'.-j^-f- -JJ'°V~-- -2
^W ^ .'vv ''$
'^ ' -yc" "^ JX-'
:' ; *.&&:£$'>
14%
I0PP^. .-'- ^.
^ 37J^"' A
Percents shown are percent of each category which both normally obtained the particular class of information
and also had to supplement this with information obtained by special means.
Figure 10
-------
APPARENT DATA DEFICIENCIES FOR "REFUSE OFFICIALS"
State Planners
(9 Replies)
Regional Planners
(5 Replies)
Municipal Planners
(21 Replies)
Operators
(13 Replies)
Manufacturers
(4 Replies)
Consultants
(14 Replies)
Researchers & Misc.
(7 Replies)
Aggregate
(73 Replies)
Land
Requirements
A
A
A
C
B
A
A
Facilities
Performance
A
B
B
A
A
A
A
Equipment
Inventory
C
B
C
Air
Pollution
C
A
B
A
C
Refuse
Quantity
A
A
A
A
A
A
A
A
Refuse
Composition
C
A
A
B
A
B
Population
C
A
B
B
B
B
Costs
of Refuse
Activities
A
B
A
A
A
A
A
A
| A [ Important plus obtained special additional data.
I B I Important-adequate data apparently available.
I £ I Not considered important but did obtain special additional data.
Figure 11
-------
STAFF USED, METHOD OF COLLECTION AND ESTIMATED COSTS
100% -
to
w
CO
25
o
P-,
CO
&3
Pi
o
H
2
W
CJ
rt
W
P-1
80% -
60%
40%
20%
OF SPECIALLY
CO
01
|>H
o
S3
r~~l
a
0 fi
tx 0
_, 4J
'(
.-
'K
', f
'
(j
cd
H
CJ
0
CO
CO
tj
cd
M
H
S-i
O
4-1
S-i 0)
O> -H
H O
i-l 0
PL, LO
PL,
CO cd
4-1 O
Pi -H
a) co
e co
PL, Ol
H 4-i
3 O
cr1 S-i
[V] p |
[ pi ,u > i !
^
^V ;.'1. -1'
j' -t"
<'?
4-1
a
4-1
,1
;3
CO
a
o
?
ill''
,v'v
'i
; '
Ki
fi
OBTAINED DATA - "REFUSE OFFICIALS"
P^i
o
p!
Ol
tiO
S-J
0)
4-1
a
H
y .'
'"' *
'.'
1 ^
"f J'
fe
, !_
i ..
i1'^
"i'' '
1- ,
u
1' *
&
^
V 1
c <
,.'
Obtained
Special Data? Staff Used?
01
H
cd
a
C3
O
H
4J
CO
a)
^j
c/
' '.
H
:,;:
l^
f^
it
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C
0)
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01 co
S-i T3
^) ^i
TO O
d o
O) 01
S Pi
4-1 P!
CJ fi g
a) o o
M S-l
H cd S-i
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CO O
~*.
^'V
;>
-; .'
h|'j
J>
"'4s
sf
;^4
'A
^.
;^:
- , -r.'
i
F''J'
^';
K_j
01
-) i -v
4-J '~^'fr\
Cd : "K
O) '.Vi
4-1 , J
H '-i
i-J i -
v«
4'^.
:-yJ
.-1 4"
'i tu-
t! rtf
| ij
'/ sfe
-1 s'S
;.- - ;,|
. \ ' X
o
o
0 0
o
,-H 0 0
« O
LO O
o ^
4-1 LO
o <«-
O 4-1
O 0 S-"
O CN O 0)
CM -cy> O >
«> 0 O
" .
O p^ ^H pr
^ ,. i ^^ ":V*
O ^''f '-jl
p! I ''^ ^ ^";- >r4"
,;f' ->^ . «| ₯:>
T/ ;-';i -'.v |^
!'?""' ', ll , S i; ' ,
S S -i ft
Method Cost of
of Collection? Special Data
(72 Respondents) (58 Respondents) (58 Respondents) (58 Respondents)
Figure 12
-------
USEFULNESS OF SPECIALLY COLLECTED INFORMATION BY "REFUSE OFFICIALS"
1 - First Choice
2 - Second Choice
3 - Third Choice
Categories
State Planners
Regional Planners
Municipal Planners
Operators
Manufacturers
Consultants
Researchers,
Authors & Misc.
Faster
Decisions
2
2
More Accurate
Basis for
Decisions
1
1
1
1
3
2
1
Saved on
Expenses
or Capital
Outlays
2
3
3
Increased
Public
Support
2
2
Improved
Services
3
3
2
More Accurate
Design of
Facilities
3
1
1
oo
I
Figure 13
-------
to these decision makers, Since the primary usefulness of data is
a "more accurate basis for decisions", and many of the categories
have sought additional data in areas where data is normally received,
then the data currently received on a normal basis is apparently
not entirely accurate for decision making.
QUESTIONS 3(e), 3(f) AND 3(g)
Additional data "Refuse Officials" might have wanted included more
information on refuse composition, quantities, land fill effects on
ground water, more information on land, air pollution and costs.
They were prevented from obtaining the additional data by time,
cost, unreliable available data, and no source for such data. None
of these factors was predominant.
QUESTION 4
In Question 4, the "Refuse Officials" were asked whether they would
like to receive certain additional types of facts from a central
data center, and if yes, what specific facts would they like to
receive.
QUESTION 4(a)
They were asked if they would like more facts on land requirements
and availability.
*They voted: 32 Yes 18 No
Specifically, they asked for more facts on:
a. Costs of land for sanitary land fill.
b. Population (served) per acre for sanitary land fill.
c. Methods of acquiring land with public support.
d. Anti-pollution requirements and restrictions.
e. Projected land needs.
The totals of Yes and No votes to each question will not
consistently add to the same number of responses. Not all
respondents voted on each part of Question 4.
-69-
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QUESTION 4(b)
They were asked if they would like more facts on efficiency and
performance of refuse facilities and equipment.
They voted: 57 Yes 7 No
Specifically, they asked for more facts on:
a. Costs of operation and maintenance.
b. Efficiency of operation.
c. Air pollution control efficiency.
d. Disposal of bulky trash.
e. Design and legal restrictions.
QUESTION 4(c)
They were asked if they would like more facts on costs and financing
of refuse operation.
They voted: 49 Yes 11 No
Specifically, they asked for more facts on:
a. True total costs with accurate division of cost between collection
and disposal.
b. Standardized installation and operating costs of various
disposal methods.
c. Comparisons of costs for private, city or county operations.
d. Financing in areas without tax help (e.g., county-wise).
QUESTION 4(d)
They were asked if they would like more facts summarizing existing
equipment and facilities.
They voted: 40 Yes 15 No
Specifically, they asked for more facts on:
a. Efficiency of operation.
b. Actual owning and operating costs.
c. Various types of equipment and where it is being used.
-70-
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QUESTION 4(e)
They were asked if they would like more facts on the quantity and
composition of refuse.
They voted: 42 Yes 14 No
Specifically, they asked for more facts on:
a. Different kinds of waste collected which must be disposed of
in land fills.
b. Sources of waste.
c. Seasonal or daily fluctuations.
d. Refuse chemical composition.
QUESTION 4(f)
They were asked if they would like more facts on population and
other factors affecting refuse produced.
They voted: 38 Yes 16 No
Specifically; they asked for more facts on:
a. Per capita generation rates for residential, commercial and
industrial refuse with seasonal and geographical influences
accounted for.
QUESTION 4(g)
They were asked if they would like more facts on recommended standards
and on regulations applicable to refuse operations.
They voted: 41 Yes 14 No
Specifically, they asked for more facts on:
a. Air pollution control requirements.
b. Ground water contamination from land fills.
c. Responsibility of private versus municipal operations.
QUESTION 4(h)
They were asked if they would like any other information not included
in Questions 4(a) through 4(g) . They asked for more facts on:
a. Legal decisions relative to solid waste disposal.
-71-
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b. Practical applications for heat recovery.
c. New disposal methods for garbage.
d. Trends in characteristics of refuse.
e. Composition of stack gases.
No significant differences were detected when the above responses
were examined by "Refuse Official" category; therefore, categorization
of the reported responses to Question 4 was not attempted. It
would not be facetious to say that the decision makers would like
as much additional data as they "can lay their hands on". Certain
of their specific requests include items of information which one
would expect them to obtain on a regular basis. That they often do
not have what they need has already been well confirmed by the
responses to Question 2 and 3. The replies to Question 4 provide
specific direction to some of the general conclusions available from
Questions 2 and 3.
QUESTION 5
The "Refuse Officials" were asked which item of Question 4 was most
important to them now, and in future planning efforts.
Question 4(a), 4(b), 4(c) and 4(e) received the greatest response
in both cases. That is, information on land, on efficiency and
performance, on costs and financing, and on quantity and composition,
is most important now and for future planning. This confirms the
findings of Questions 2 and 3.
QUESTION 6
The "Refuse Officials" were asked whether they primarily use con-
sultants in formulating plans.
19 said Yes 31 said No
If the consultant category is excluded, this vote is 17 Yes and
23 No. It is interesting that most say that they do not use
consultants in planning for new refuse equipment and facilities.
It has been generally accepted that consultants are more widely
used than this response would indicate.
QUESTION 7
This question asked the "Refuse Officials" to indicate their preference
for outside source(s) of data. The results indicate that their
primary sources for outside data are professional societies and
consulting firms.
-72-
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QUESTION 8
This question was intended to explore their experience with what
was referred to as a "central information center". They were asked
if they had ever been prevented from obtaining data from one.
They voted: 31 Yes 32 No
Of the 31 who voted Yes, 25 said it was because there was "no
information center".
Apparently, the potential users of an information center are divided
in their concepts of what constitutes such a center. Half say that
no such center exists. The other half apparently considers certain
outside sources as information centers and, therefore, indicate
that they have had no trouble using them. In either case, it seems
that once a center is established and publicized, it would be
used.
3. DISCUSSION OF "DATA SYSTEM SPECIALISTS" QUESTIONNAIRE
The "Data Systems Specialists" questionnaire was designed to
determine the nature and extent of problems which are encountered
in achieving effective use of information systems for governmental
agencies. Categorization was used to facilitate the development of
a mailing list, but it is not considered significant to report the
responses by categories, partly because the total response (27 out
of 68) is not large enough to allow it to be sub-divided to any great
extent, but also because the main purpose of the questionnaire
phase of the information system feasibility study was to establish
the information and decision making needs and practices of the
potential users. The surveying of the designers of information
systems as to the problems they encounter in their work with
governmental agencies was a secondary objective and the results
will be reported in that context.
QUESTION 1
The "Data Systems Specialists" consider that their work deals
primarily with the area of "data analysis". "Data handling"
(processing, etc.) and "data" collection are less important.
QUESTION 2
Figure 14 graphically illustrates the responses to Question 2. The
majority of the respondents developed and anlayzed special data for
municipal officials within the past year. They primarily used
their own staffs and, to a lesser extent, government agencies, to
obtain the data. They used interviews, questionnaires and literature
searches, and recorded the data by keypunch and written means.
Data transmission was primarily by report and punched cards.
-73-
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RESPONSES TO DATA SYSTEM SPECIALISTS QUESTIONNAIRE
100% -J
80%-
60%
20%-
How Transmitted to
Processing Center?
Method of
Collection?
How
Recorded?
Best Source of Data?
(16 Responses)
Staff Used?
(16 Responses)
(16 Responses)
(16 Responses)
Developed
and
Analyzed
Special
Data For
Municipal
Officials?
(23 Re-
sponses)
Figure 14
-------
The majority used special machines to process the data, and only
reports were used to transmit the results to data users (as opposed
to more rapid or electronic means).
Estimates of cost for collection, handling and analysis of data
ranged from a few thousand to over 100,000 dollars.
The usefulness of the data was primarily in providing a more
accurate basis for decisions. There was little order of preference
shown in the five other choices given (faster decision, savings,
increased public support, improved services, more accurate design),
and they were rated significantly below the first choice.
Almost all respondents wanted to develop additional data, but were
prevented from obtaining it primarily by time and cost.
QUESTION 3
They were asked to indicate their preference for outside sources of
data. The results are shown on Figure 14. They depend primarily on
government agencies. In contrast, the "Refuse Officials" prefer
professional societies, trade associations and consultants.
QUESTION 4
When questioned as to any difficulties they may have had in suggesting
or using a central information center, the majority responded that
they had no such difficulties. Of those that did, only four
indicated that it was because there was "no available information
center". Four said it was because costs were too high and four
because of lack of standardization.
As expected, then, these respondents have a better concept than did
the "Refuse Officials" of what central information centers are and
the majority have had some experience with them.
QUESTION 5
When asked why they thought some central data systems have been
unacceptable to municipal officials, cost was given as the primary
reason. Some responses also indicated that a basic mistrust of
unknown and mysterious technology often makes information and data
systems unacceptable.
QUESTION 6
This question explored the respondents' need for data relative to
municipal refuse. About 43 percent of the respondents said that
they needed such data. As to their choice of data categories
(Figure 7), they expressed an equal need for all the data. With
respect to the reporting of this information, most wanted regular
reports on a monthly or yearly basis.
-75-
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In general, the response to the "Data Systems Specialists" question-
naire provided no surprising results. There is perhaps less tendency
toward "exotic" techniques than might have been supposed (micro-wave
data links, fascimile transmission of reports, digital data recording
in-the-field, etc.)- More or less conventional techniques are
used in conjunction with the computer hardware.
Comparison of what "Refuse Officials" estimated for the costs of
their special data, and what the "Data System Specialists" estimate
for the costs of their projects, points out clearly why the major
difficulty in obtaining central data system acceptance has been the
cost factor (Question 5). Where the "typical special data" project
for the "Refuse Official" might be estimated to cost $5,000, the
"typical" project by the "Data System Specialist" might be $30,000.
It is not unreasonable to suppose that there are some costs missing
from the former, but not enough to make up the entire difference.
One possible explanation for the discrepancy is that the "Data
Systems Specialist" is perhaps more thorough in analyzing his true
data needs, whereas the "Refuse Official" would be more likely to
"get as much as he can for the money available".
4. DISCUSSION OF INTERVIEWS
A limited number of personal interviews were conducted in order to
obtain a more detailed analysis of present information practices,
information needs, and possible applications of an information
system if one were available. A total of twenty-one interviews
were conducted as follows:
State Planners 3 Interviews
Regional Planners 3 Interviews
Municipal Planners 5 Interviews
Operators 2 Interviews
Consultants 4 Interviews
Researchers 3 Interviews
Equipment Manufacturers 1 Interview
The interview results were reviewed by specific categories to
determine correlations, or to define any significant differences
which might exist. In general, the interview results tend to confirm
the questionnaire results in all categories. It is significant to
note that there do exist some differing viewpoints on refuse infor-
mation among the various categories. For example, state planners
and consultants hold the view that the information presently avail-
able on refuse activities is shallow in nature and not extensive or
standardized enough to aid in planning and decision making. The
consultants seemed to agree that the "state-of-the-art" of refuse
activities is at a low level and has remained essentially unchanged
for many years. Both state level officials and consultants felt
that improved information generation and availability is necessary
before the "state-of-the-art" can be significantly upgraded and
before refuse activities can be significantly improved upon.
-76-
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On the other hand, regional officials, municipal officials and
operators involved in refuse activities saw a problem in information
availability but did not imply that the progress of refuse activities
is seriously hampered by this problem. Regional agencies indicated
that they are just beginning to initiate serious activities in this
area and have not yet become deeply enough involved to recognize
all the longer range problems. Municipal officials seem to be deeply
involved in and concerned about refuse activities, but deal more in
the nearer term. Longer range planning activities must often take
a back seat because of the pressure of the more immediate problems
of the next few years. They also rely on consultants to provide the
suggested solutions to the longer range problems and, therefore, they
expect the consultant to be the one primarily concerned with infor-
mation availability.
In all cases, the need for and the concept of an information system
for refuse activities was recognized as a desirable step toward
improving the overall situation. Opinions differed as to the use of
such a system. State agencies, regional agencies and consultants
were primarily concerned with the longer range planning applications
of such a system. Municipal planners and operators indicated more
interest in the more immediate term, operational applications of
the system. Researchers appear to be primarily interested in the
detailed aspects of refuse composition and analysis, which could be
categorized as a long range planning problem.
The comments made by those interviewed fell into several categories
as follows: (Much of the text to follow is extracted from the inter-
view reports.)
a. PRESENTLY AVAILABLE DATA
In general, the comments agree that certain problems exist in
obtaining accurate information. The principal problems seem to
be (1) the unavailability of information, (2) inaccuracies in
the information which is available, and (3) standardization
of information. For some factors such as refuse composition and
air pollution, very little information is available anywhere.
For other factors such as quantities of refuse and land avail-
ability, the availability of information depends on the record
keeping practices of the municipality involved.
The information which is available is often considered inaccurate.
As one interviewee put it, "information exists in great pro-
fusion, but its accuracy is questionable". Part of this is
apparently due to the methods of obtaining the data, which
include rough, non-scientific means of measurement. Part is
also due to a lack of completeness of the data. In many
localities, facilities such as scales are not available and
any records kept are sketchy and spotty. The relevant variables
are often not identified. Rough estimates are often used to
define refuse quantities and composition.
-77-
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Standards are not used in defining the information which is
available. Consultant studies are non-standard in natu-re and
the,reports vary as to-what information is actually included.
Comments made by consultants indicate that heat values, for one
example, are usually undefined as- to whether they are high or
low, or based on wet or dry analysis. Air pollution data is
usually far too general to be of any real use. Further comments
indicate that there are gaps in the data as to what reported
quantities really represent and what they include or do not
include. This is particularly true with regard to information
on operating costs and refuse quantities. In summary, the
available information appears to lose its value because of poor
definition, thus creating foggy communications.
b. INFORMATION NEEDED
Municipalities, regulatory bodies, consultants and equipment
suppliers all indicated a need for more, better and more
standardized information. The exact nature of the information
needed" would depend on its intended use. Some factors mentioned
included:
(1) Land use requirements.
(2) Air pollution regulations.
(3) Tonnages and compositions by cities, areas, regions, etc.
(4) Historical trends.
(5) Data on refuse density and compactibility.
(6) Data on equipment performance.
(7) Statistics on "typical" smaller and larger cities.
c. INFORMATION SYSTEM OUTPUT
The output of an information system should be an answer to a
specific question. The system must work out the answer from
available memory information and other inputs. The accuracy of
the output is, of course, dependent on the accuracy and value
of the inputs. The information system input should include
consultants' reports, annual municipal reports and annual
independent surveys of municipalities.
The information system would have to interpret the meaning of the
information fed into it. One interviewee pointed out that data
can be standardized, but the questions asked cannot be. Standard
factors for data seldom match the factors present in a specific
question. In answering any particular question or request for
information, the question's factors must be matched to the data
-78-
-------
factors and then appropriate modifications in the data made in
order to provide a useful and accurate answer. The factors
present in a specific question depend to a large extent on the
agency asking the question and on what will be done with the
answer. The system should be designed with sufficient
flexibility to respond to virtually any request for output
information.
A central information center could handle only certain general
information concerning land requirements and land availability.
Specific information for a particular city on population and
land availability at a specific time would have to come directly
from that city. These factors would be subject to frequent
change and to many outside influences such as zoning changes,
politics and public attitude.
As to availability, the basic question to answer is, "What is
the optimum way to make the information available in a usable
form?" Should it be stored on tapes at a remote location and
should it be periodically printed and published in report form?
In some cases, the individual is not really sure what information
he needs to make a decision, nor does he know what information
may be available to him. A basic requirement of the information
system would be to process the data. A decision maker or planner
needs to know what is going to happen and what he can do about
it; not what the population is, or what the refuse quantity is.
These factors are merely components of the answer he desires.
d. VALUE OF AN INFORMATION SYSTEM
The interviewees generally agreed that there is value to the
concept of an information system for refuse activities. There
are, however, a number of interpretations given to this "value".
One comment indicated that the primary value of an information
system would be for broad planning purposes as a first approach
to a specific problem. Another felt that a very important
function of an information system would be for gathering of
actual experience data from municipalities to be used as a guide
where this information is not now available.
The opinion was expressed that for smaller communities, infor-
mation of a local nature on other, similar communities refuse
operations, would be useful. For the major cities, however,
their individual problems are too unique in most cases to bear
any significant resemblance to other large cities or to the
smaller cities.
In a broad sense, there is a need for a central data system to
serve as the basic stimulus for upgrading the "state-of-the-
art". In a narrower, or shorter term, it would be useful as
an operational aid to communities, particularly with regard to
collection systems.
-79-
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It would be very difficult to determine the actual pay-out of an
information system. This basically depends on the quality of
the information available and how much help it is to the person
using it. In certain cases, it might be possible to attach
dollar figures to the benefits resulting from the use of an
information system. In most cases, however, these benefits
would be of an intangible nature and it would be very difficult,
if not impossible, to attach direct dollar figures to their
value.
Some comments implied that consultants and professional planners
such as regional planning agencies would probably benefit the
most from an information system because they are the ones
primarily concerned with actual development of long range plans
for refuse handling. Other comments indicate that all parties
concerned with refuse activities would benefit from such a system,
but some to a lesser extent than others.
e. GENERAL COMMENTS
The greatest problem to be faced in utilizing an information
system would be in convincing the mayor and city engineers on
the usefulness of the information. In one instance, it was
pointed out that immediate operational application of the
system, resulting in quickly realizable cost benefits, would be
necessary to gain acceptance by municipal officials.
The most basic need with regard to an information system is a
standardization of (1) units of measurement and (2) ways of
reporting. To be of any value, an information system must
contain accurate standardized information and must be able to make
this information readily available to those who might need it.
Screening of incoming information would be necessary to make
sure it is in a usable form. The information which municipal
people have is usually out of date and inadequate for accurate
planning purposes. Minimum requirements should be set for
doing studies and for reporting the information. For example,
a minimum time period for physical measurement should be required.
These minimums should be set up as legally required standards
in order to insure that they will be met.
One area where valuable information is being generated, but the
information is not available to those who could utilize it, is
the area of consultant studies for specific municipalities.
In most cases the reports submitted by the consultants are not
available from the cities and less often from the consultants
themselves. This represents an untapped source of planning
information which certainly should be included in any information
system.
-80-
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D. CONCLUSIONS
1. The data normally obtained by the various categories of "Refuse
Officials" is usually insufficient for their decision making needs
and additional special data must be obtained. This includes routine
data such as refuse quantity and costs of refuse activities.
2. The primary decision area of the "Refuse Officials" is that of long
range planning, and most data obtained is used in formulating these
plans and to provide a more accurate basis for the decisions
involved. A refuse information system should therefore, be oriented
toward serving planning decisions.
3. Regional planners and consultants consider the broadest range of
information important in making decisions. They will probably
be the most likely user category to benefit from a refuse infor-
mation system.
4. The greatest data "gap" at present is in the area of "land require-
ments" and "facilities performance". The planners of facilities
apparently have difficulty in finding appropriate locations for the
facilities and in knowing what performance they can expect.
5. Data on air pollution, refuse composition and population were not
considered important by more than half the respondents, yet about
30 percent of them obtained special data in these areas.
Apparently, the importance of this data is gradually being recognized
6. Refuse officials probably would welcome a central information center
if it served their specific information and decision area needs,
and if the costs to them were minimal.
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MUNICIPAL REFUSE DATA SYSTEMS SURVEY
(COLLECTION, STORAGE AND DISPOSAL)
TO:
COMPILATION
QUESTIONNAIRE "A"
Total
livable,
Total Se.nt
P&ic.e.ni
77
70
! (a) Are you regularly required to make decisions regarding municipal refuse
activities?
YES | go | NO
(b) Are these decisions primarily involved with:
Long range planning (_5 yr. or more) of new facilities? I 2.3
'lease number in
order of importance
Obtaining public support for plans? | 3.9 |
Evaluating the effectiveness of plans? | 3. 3 |
Establishing standards and regulations? I 3.6 J
Operation of refuse facilities and equipment? 3.6
Evaluation of the performance of refuse facilities? 3.1
Other, please specify InteAme.d,iati pla.nru.ngi 1 .
UateJi pollution aApe.ctA .
SouAce. Of) na^a&iL, -i.i, -inda^ttviat, c.om-
, Jiulde.ntA.al, tAa{}f,-Lc.
-------
3. Within the past year, has an important decision required you to obtain special
additional data?
YES | $8 \ NO
(a) If YES, which areas did the "special" data cover?
H
Land requirements
Facilities performance
Inventory of equipment
Air pollution
I n j
QD
CD
Quantity of refuse
Composition of refuse
Population
Costs of refuse activities
Other, please specify
35
79
U
37
Wcute.fi poU.utA.on 7ote.ntA.at Social
(b) How did you obtain the "special" data? Method 0& d-UpO-f>al - Management
ftoot ajuia.
Staff used:
Your own
Equipment supplier
Professional Societies
or Trade Associations
Method of Collection:
Interview
Questionnaire
QD
CTD
Consultant
Government agenc>
University
Other, please specify
Direct measurement
Literature search
data. pu.bticatA.O'/U>.
11
Route. -4-tudf/; \)Lt,JJtA.ng othoji
Other, please specify Your own records
by
(c) How much do you estimate the "special" data cost?
0 - $200 | 9 $201 ^ $1000
$1001 - $5000
If over $5000, please check 75_
(d) In what way was the data most useful?
Faster decisions
More accurate basis for decisions
Saved on expenses or capital outlays
Increased public support
Improved services
More accurate design of facilities
Other, please specify
(or indicate approximate cost, if it
is not confidential __ )
$70,000, $15,000, "$40,000
Re/i pont>ej> we/ie
njjT ~\ to obtain th^e.
I
Please number
/ in order of
I importance
Ac^cci
)
to
, de.ve2opme.nt of,
boxS'tc data no degA.ee o'J
change, of,'"poLltA.u" {an. gfie.ate.fi b
-83-
-------
(e) If you were in a similar situation again, would you spend that money again?
YES
NO
(f) What additional data would you also have wanted?
See cuttcLC.ke.d
(g) What factors prevented you from getting the additional data?
Time / 1 |
Cost I 12 1
Other, please specify _ No
Available data unreliable
No source for such data
4. If a central data center [from which you could receive rapid response to your requests
for datajwere set up, which of the following data would you like to receive from the
center?
a. More facts on ]and requirements and land availability?
If YES, what kind of facts? See attachud t>h
-------
5. Which of the facts in quc-stion A is most important to you?
(.0 Now? a (14), fa (17). c (13), d (7) & (18), j (51 9 (5), *i (?) all
(b) In future planning efforts? a (75), b (75), CL (6), d (91. la-{}j, PeAAonal t>tu.dijr APWA, tq alp
manufjae-tu/ieAi own d&ta to max.
,, -LnteAeAtzd ^aae.tf, ofc tke.
YES
If YES, was it because:
(please check factor or factors which apply)
NO
Cost too high
Too slow
Unreliable
Outdated data
Not standardized
Only national data
Only local data
Data not clear
No information center
Other, please specify
0
25
Thank you for your cooperation.
PLEASE RETURN THIS QUESTIONNAIRE USING THE ENCLOSED SELF ADDRESSED STAMPED
ENVELOPE, AS SOON AS POSSIBLE.
If you would like to expand further on the subject at a later date, please
check here
Did we address the letter correctly?
If not, please give corrections
-85-
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COMPOSITE REPLIES TO QUESTION 3(f)
1. More information on composition of waste.
2. More information on quantities of waste (variation, per capita generated)
3. Potential effect of sanitary land fill on ground water.
4. Available land.
5. Air pollution.
6. Costs of operating and maintaining all types of equipment.
COMPOSITE REPLIES TO QUESTION 4
4(a)
1. Costs of land for sanitary land fill
2. Population/acre for sanitary land fill.
3. Methods of acquiring land with public support.
4. Restrictions - anti-pollution requirements.
5. Projected land needs.
4(b)
1. Cost of maintenance (operation).
2. Nature of residue after processing.
3. Efficiency of operation (burning and operation).
4. Air pollution control efficiency.
5. Disposal of bulky trash.
6. Collection equipment.
7. Design and legal restrictions.
4(c)
1. True total costs with accurate division of cost between collection and
disposal.
2. Costs of various disposal methods compared in uniform units (tons)
(installation and operation costs).
3. Financing in areas without tax help (county-wide).
4. Comparison of cost for private, city or county operations.
4(d)
1. Efficiency of operation.
2. Actual owning and operating costs.
3. Various types of equipment and where it is being" used.
4(e)
1. Accurate records of different kinds of waste collected which must be
disposed of in land fills.
2. Accurate records on source of waste.
3. Records on seasonal or daily fluctuations.
4(f)
1. Generation rates, residential, commercial, industrial, seasonal and
geographical.
2. Per capita generation.
-------
COMPOSITE REPLIES TO QUESTION 4, Cont,
4(g)
1. Air pollution control requirements.
2. Ground water contamination from land fills.
3. Responsibility of private versus municipal operations.
4(h)
1. Legal decisions relative to solid waste disposal.
2. Practical applications for heat recovery.
3. New disposal methods for garbage (other than land fill)
4. Trends in characteristics of refuse.
5. Combustion of stack gases.
-87-
-------
TO:
MUNICIPAL REFUSE DATA SYSTEM SURVEY
DATA SYSTEMS DEVELOPMENT
COMPILATION
OUESTIOWNAIRE "8"
Total.
Totai Sent
PeA.ne.nt LMab£e
27
23
68
34%
The objective of this questionnaire is to help evaluate the feasibility of an infor-
mation system for municipal solid waste activities. As a developer of data systems
which assist municipal decision-makers, your responses will be an important factor in
the evaluation. It will help assess current municipal data system practices and to
determine the problems of getting such systems into effective use.
This questionnaire is being sent to you as one of a group of selected data system
developers. A second questionnaire covering specific data needs is being sent to
municipal refuse officials.
1. Are your responsibilities most concerned with:
Data collection (field testing, interviews, etc.)
Data handling (transmission, processing, etc.)
Data analysis (systems, operations research, etc.)
Other, please specify
to obtain thue, fi.atin.qA.
I Please number
IJ. 9 | -sin order of
/importance
^^
2. Within the past year, has a study requirement made it necessary for you to
develop and analyze special data for municipal officials?
YES
NO
(a) If YES, how did you obtain the special data?
Staff used:
Your own
Equipment Supplier
75
Professional Societies
or Trade Associations
Consultant
Government Agency
University
If other, please specify
(b) Method of Collection:
Interview
Questionnaire
Direct Measurement
Literature Search
Other, please specify _..
(c) How was the data recorded?
Written
Keypunch
Automatic Electronic Recording
If other, please specify
-------
(d) How was the data transmitted from point of collection to the processing
center?
Report
Telephone
Telemetered
I 73 I
cn
Punched Card I 1 \
Magnetic Tape
If other, please specify
(e) Did you use special machines to automatically or electronically process the
data?
YES I Bj No | "6~|
(f) If YES, could you list these machines?
(g) How did you have the results transmitted to the data users?
Report | 16 I Electronic Data Links | 0
Telephone [ 0 \ If other, please specify
(h) What is your estimate of the costs in time and/or dollars?
For data collection (field test, etc.)
For data handling (processing, etc.)
Hours Dollars
4 M^ 80,000, 50,000,
150,000
20-40 IW" 750, 2,500, 30,000
100,000
For data analysis (systems, operations research, etc. )7 6-20 M 7 5 0^ 1,000, 50,000
100,000
Other, please specify
(i) In what way was the data most useful to your client?
Faster decision
More accurate basis for decision
Savings on expenses or capital outlays
Increased public support
Improved services
More accurate design of facilities
If other, please specify
Please number in order
"S of importance those
h . 7 I Ifactors which apply.
ITTl
to obtctin theAe.
(j) Was there additional data you would also have wanted to develop?
YES I 74l No f 2 I
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-3-
(k) What factors prevented you from developing the additional data?
Time [ 72 ] Unreliable available data j
Cost ''
77
No source for such data
LL
If other, please specify
3. In getting data from outside sources, which of these sources most satisfy your need
for reliable and complete data?
Government Agency
Professional Societies
or Trade Associations
Consulting Firm
Fed'l State Local
8
University
Other, please specify
4. Has there ever been something which prevented you from suggesting or using a
central information center?
YES
If YES, was it because:
(Please check factor or factors which apply)
NO
13
Cost too high !4
Too slow I Q
Unreliable I0~
I.,. -
Outdated data | ?
Not standardized 4
Only national data
Only local data
Data not clear
No available information center
Other, nlease specify __
| 0 \
ra
jj
5. From your experience, why have some central data systems been unacceptable to
municipal officials?
cost Irn
Mistrust of data
Mistrust of outside information system personnel
Reluctant to use standard costing and performance factors
Reluctant to use labor-saving or time-saving equipment
Other, please specify, : ; ,
JlJ
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-4-
6. Do you need further data relative to municipal refuse for your work?
YES | I'D I NO [_?D
If YES, what kind of facts would this data include?
Land requirements I B \ Quality of refuse | 5
Facilities performance | 6_| Composition of refuse | 7_
Inventory of equipment | $_\ Other, please specify
Air pollution | 7 j
If this information were made available, in what form would you like to receive it?
a. Regular report | 9 | Special report at your request ) 5 |
b. If regular report, how often?
Weekly f~T1 Monthly | f\ Yearly
PLEASE RETURN THIS QUESTIONNAIRE USING THE ATTACHED SELF ADDRESSED STAMPED ENVELOPE, AS
SOON AS POSSIBLE.
If you would like to expand further on the subject at a later date, please check here
Did we address the letter correctly?
If not, please give corrections
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SECTION VII
APPENDIX B
COST CALCULATIONS FOR SYSTEMS EVALUATIONS
A. ASSUMPTIONS
Cost estimates are based on certain assumptions concerning unit costs
for each of the factors and functions involved'. The assumptions used
are as follows. Other assumptions are given in the detailed cost
summaries as required.
B. LABOR RATES
The following were the labor rates, including overhead, which were used
in the cost calculations. Where a range is given, the upper end
(underlined) was used; these represent typical rates from service
bureaus and consultants.
Category Rate (including overhead)
Administrative Director $20/hour
Systems Analyst $12 to $17.50/hour
Computer Programmer $10 to $15/hour
Research Librarian $10/hour
Field Inspector $ 9/hour
High Level Systems Assistant $ 9/hour
Keypunch Operator $ 8/hour
Medium Level Systems Assistant $ 7/hour
Secretarial $ 6/hour
Weighing Scale Operator $4.50/hour
Clerical Assistant $4.50/hour
C. COMPUTER RATES
The following are the machine rates used in the cost estimates:
Computation $300 to $450/hour/ use $375/hour
Printing $100 to $150/hour; use $125/hour
D. MISCELLANEOUS
Reproduction, including printing, collating, binding, etc. $.04/page
Mailing, average $.25/item
E. COST ESTIMATES BY SYSTEM
The estimated cost for each type of information system discussed in
Section V-C has been calculated using the foregoing assumptions. The
cost details are as follows.
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COST ESTIMATES
System #1
DATA CLEARINGHOUSE SERVICE
Cost Factor
A. Data Gathering,
1. Questionnaire
Questionnaire design @ $15/hr
Reproduction: 36,000 copies @ $.04
Mailing & handling 6,000 @ $.25
2. Data from other sources
First review @ $10/hr
Annual full time scrutiny
B. Data Processing
1. Questionnaire
Manual preparation @ $7/hr
Keypunch & verify @ $8/hr
Conversion to tape @ $375/hr
2. Data from other sources
Manual preparation (incl. in A-2)
Keypunch & verify @ $8/hr
Conversion to tape @ $375/hr
C. Programming
Conversion, screening, file
Maintenance, calculations , report
Generation & miscellaneous @ $15/hr
Systems analysis @ $17.50/hr
Annual programming @ $15/hr
D. Computation
Test & calculation @ $375/hr
Printing @ $125/hr
E. Reproduction & Distribution
40 pg. annual report, 6,500 copies
6 pg. monthly report, 6,500 copies
730,000 pages @ $.04
Mailing & handling 83,500 @ $.25
F. Administration
Administrative director @ $20/hr
Clerical help @ $6/hr
Supplies and equipment (misc.)
First Cost
(Also First Year)
Hours
700
1,200
700
700
7
2,500
20
2,000
350
20
10
2,000
4,000
Dollars
10,500
1,400
1,500
12,000
4,900
5,600
2,625
20,000
7,500
30,000
6,125
7,500
1,250
29,000
21,000
40,000
24,000
2,000
Annual Cost
Hours
160
2,000
700
350
2
600
5
650
10
10
Dollars
2,400
1,400
1,500
20,000
4,900
2,800
750
4,800
1,825
9,750
3,750
1,250
29,000
21,000
40,000
24,000
2,000
Total
Ten Year Total
225,415
1,765,540
171,125
NOTE:
All costs are estimated at +20% of the values shown.
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COST ESTIMATES
System #2
J- ixijjjj.^j. J_ VH -Ll.NrUKivIH.l J.U1N OUKVIUJI
Cost Factor
A. Data Gathering
1. Sample Cities (50 cities)
Installation of weighing scales
@ $10,000 per city
Maintenance costs @ $200 each/yr
Operator @ $4.50/hr
Clerical help @ $4.50/hr
Inspection: 1st yr @ $9/hr
2nd-5th yr @ $9/hr
5th-10th yr @ $9/hr
Subtotal
Design of data gathering system
(forms, procedures, controls,
reports, etc.) @ $17.50/hr
Reproduction, mailing, handling, etc.
2. Data from other sources
First review @ $10/hr
Continuing scrutiny @ $10/hr
B. Data Processing
1. Sample cities (50 cities)
Manual processing, 4 reports/yr
2 hrs/report @ $7/hr
Keypunch & verify
Assume 100,000 char annually per
city, or 12.5 hrs KP & 12.5 hrs
verify @ $8/hr
Conversion to tape @ $375/hr
2. Data from other sources
Estimate 5 yi 10 characters initially
Estimate 1 x 10 characters annually
Keypunch & verify @ $8/hr
Conversion to tape @ $375/hr
C. Programming
Conversion, screening, file mainten-
ance, calculations, report generation
& miscellaneous @ $15/hr
Systems analysis @ $17.50/hr
Redesign at 5th yr @ $15/hr
Annual programming @ $15/hr
First Year
(Also First Year)
Hours
130,000
52,000
3,000
900
500
400
1,250
5
1,250
10
3,300
1,500
1,250
Dollars
500,000
586,000
234,000
27,000
1,347,000
15,750
1,000
5,000
2,800
10,000
1,875
10,000
3,750
49,500
26,250
18,750
Annual Cost
Hours
130,000
52,000
1,500
1,000
300
400
1,250
5
250
2
650 .
Dollars
10,000
586,000
234,000
13,500
9,000
852,500
1,000
3,000
2,800
10,000
1,875
2,000
750
9,750
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System #2
PREDICTIVE INFORMATION SERVICE, Cont.
Computation
Test @ $375/hr
Calculation: 5,000 regressions @
11 sec. @ $375/hr
Printing @ $125/hr
Reproduction & Distribution
80 pg. annual report to 6,500,
520,000 pages @ $.04
Mailing & handling 6,500 @ $.25
Administration
Administrative director @ $20/hr
Clerical help @ $6/hr
Supplies & equipment (misc.)
Total
Ten Year Total
30
25
15
2,000
8,000
11,250
9,375
1,875
20,800
1,600
40,000
48,000
2,000
25
15
2,000
8,000
9,375
1,875
20,800
1,600
40,000
48,000
2,000
1,607,825 1,007,325
]D,692,500
NOTE: All costs are estimated at + 20% of the values shown.
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COST ESTIMATF.S
System #3
PLANNING INFORMATION SERVICE
Cost Factor
A. Data Gathering
1. Questionnaire
Questionnaire design @ $15/hr
Reproduction 36,000 copies @ $.04
Mailing & handling, 6,000 @ $.25
2. Data from other sources
First review @ $10/hr
Continuing scrutiny @ $10/hr
3. Request handling
200 requests/yr, 1/3 adjusted
@ $9/hr
B. Data Processing
1. Questionnaire
Manual preparation @ $7/hr
Keypunch & verify @ $8/hr
Conversion to tape @ $375/hr
2. Data from other sources
Estimate 5 x 10^ characters initially
Estimate 1 x 10& characters annually
Keypunch & verify @ $8/hr
Conversion to tape @ $375/hr
3. Request handling
Assume 10,000 char/request
Keypunch & verify @ $8/hr
Conversion to tape @ $375/hr
C. Computer Programming
1. Questionnaire results & other data
Conversion, screening, file
Maintenance, calculations, report
Generation and miscellaneous
@ $15/hr
Systems analysis @ $17.50/hr
Subtotal
Annual maintenance @ $15/hr
2. Facilities timetables program
Preliminary study @ $17.50/hr
Program preparation, debugging &
trial application @ $15/hr
Subtotal
Annual maintenance @ $15/hr
First Cost
(Also First Year)
Hours
700
500
2,400
700
700
7
1,250
10
700
7
1,200
200
150
350
Dollars
10,500
1,400
1,500
5,000
21,600
4,900
5,600
2,625
10,000
3,750
5,600
2,625
18,000
3,500
21,500
2,625
5,250
7,875
Annual Cost
Hours
160
300
2,400
700
350
2
250
2
700
7
200
100
Dollars
2,400
1,400
1,500
3,000
21,600
4,900
2,800
750
2,000
750
5,600
2,625
3,000
1,500
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System #3
PLANNING INFORMATION SERVICE, Cont.
C. Computer Programming, (Cont.)
3. Planning optimization program
Preliminary study @ $17.50/hr
Program preparation, debugging and
Trial application @ $15/hr
Subtotal
Annual maintenance @ $15/hr
4. Operational optimizations program
Preliminary study @ $17.50/hr
Program preparation, debugging and
Trial application @ $15/hr
Subtotal
Annual maintenance @ $15/hr
5. Non-standard requests program
Preliminary study @ $17.50/hr
Program preparation, debugging and
Trial application @ $15/hr
Subtotal
Annual maintenance @ $15/hr
Redesign at 5th year 25%
Programming Total (not including
redesign)
D. Computation
Test @ $375/hr
Calculation @ $375/hr
Printing @ $125/hr
E. Reproduction & Distribution
200 requests @ 10 pg. @ 20 copies
@ $.04/copy
Mailing & handling, 4,000 @ $.25
F. Administration
Director @ $20/hr
Clerical help @ $6/hr
Supplies & equipment (misc.)
Total
Ten Year Total
500
1,050
500
1,050
400
700
100
200
50
2,000
4,000
8,750
15,750
24,500
8,750
15,750
24,500
7,000
10,500
17,500
24,000
95,875
37,500
75,000
6,250
1,600
1,000
40,000
24,000
2,000
200
200
150
200
50
2,000
4,000
3,000
3,000
2,250
12,750
75,000
6,250
1,600
1,000
40,000
24,000
2,000
358,325
2,289,650
211,925
NOTE: All costs are estimated at +20% of the values shown.
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COST ESTIMATES
System #4
INFORMATION SERVICE
Cost Factor
A. Data Gathering
1. Sample cities (See System #2)
2. Data from other sources
(See System #2)
3. Request handling (See System #3)
B. Data Processing
1. Sample cities (See System #2)
2. Data from other sources
(See System #2)
3. Request handling (See System #3)
C. Computer Programming
1. Sample cities (See System //2)
2. On request programs (See System #3)
3. Five year redesign
D. Computation (See Systems #2 and #3)
1. Tests
2. Calculation
3. Printing
E. Reproduction & Distribution
(See Systems #2 and #3)
1. Reproduction
2. Mailing & handling
F. Administration
1. Administrative director
2. Clerical help
3. Supplies & equipment (misc.)
First Cost
(Also First Year)
Hours
Dollars
0,363,750
5,000
21,600
14,675
13,750
8,225
75,750
85,000
40,000
48,750
84,335
8,125
22,400
2,600
40,000
60,000
3,000
Annual Cost
Hours
Dollars
853,500
3,000
21,600
14,675
2,750
8,225
9,750
10,000
84,375
8,125
22,400
2,600
40,000
60,000
3,000
Total
Ten Year Total
1,857,000 1,134,000
12,103,000
NOTE: All costs are estimated at +;20% of the values shown.
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COST ESTIMATES
System #5
DATA CLEARINGHOUSE AND
PREDICTIVE INFORMATION SERVICE
Cost Factor
A. Data Gathering
1. Sample cities (See System #2)
2. Data from other sources
(See System #1)
B. Data Processing
1. Sample cities (See System #2)
2. Data from other sources
(See System #1)
C. Programming
1. Clearinghouse (See System #1)
2. Sample cities (See System #2)
3. Redesign at fifth year
D. Computation
1. Test (See Systems #1 and #2)
2. Calculation (See Systems #1 and #2)
3. Printing (See Systems #1 and #2)
E. Reproduction & Distribution
1. Reproduction (See Systems #1 and #2)
2. Mailing & handling
F. Administration
1. Administrative director
2. Clerical help
3. Supplies & equipment (misc.)
First Cost
(Also First Year)
Hours
Dollars
1,363,750
12,000
14,675
27,500
18,000
77,000
18,750
15,000
16,875
3,125
40,000
22,000
40,000
60,000
3,000
Annual Cost
Hours
Dollars
853,500
20,OOC
14,675
6,625
6,OOC
9,75C
16,875
3,125
40,000
22,000
40,000
60,000
3,000
Total
Ten Year Total
1,712,925 1,095,550
11,591,625
NOTE: All costs are estimated at +20% of the values shown.
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COST ESTIMATES
System #6
DATA CLEARINGHOUSE AND
PLANNING INFORMATION SERVICE
Cost Factor
A. Data Gathering (See Systems //I and #3)
1. Questionnaire
2. Data from other sources
3. Request handling
B. Data Processing (See Systems #1 and #3)
1. Questionnaire
2. Data from other sources
3. Request handling
C. Computer Programming
(See Systems #1 and #3)
1. Questionnaire and other data
2. Request programs
3. Redesign at fifth year
D. Computation (See Systems #1 and #3)
1. Test
2. Calculation
3. Printing
E. Reproduction & Distribution
(See Systems #1 and #3)
1. Reproduction
2. Mailing & handling
F. Administration (See Systems #1 and #3)
1. Administrative director
2. Clerical help
3. Supplies & equipment (misc.)
First Cost
(Also First Year)
Hours
Dollars
13,400
12,000
21,600
13,125
27,500
8,225
36,125
74,375
24,000
41,250
78,750
7,500
30,600
22,000
40,000
36,000
3,000
Annual Cost
Hours
Dollars
5,300
20,000
21,600
8,450
6,625
8,225
9,750
9,750
78,750
7,500
30,600
22,000
40,000
36,000
3,000
Total
Ten Year Total
465,450
3,257,400
307,550
NOTE:
All costs are estimated at +20% of the values shown.
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COST ESTIMATES
System #7
SERVICE WITH DATA CLEARINGHOUSE
Cost Factor
A. Data Gathering
1. Sample cities (See System #2)
2. Data from other sources
(See System #.3)
3. Request handling (See System #3)
B. Data Processing
1. Sample cities (See System #2)
2. Data from other sources
(See System #1)
3. Request handling (See System #3)
C. Computer Programming
1. Clearinghouse (See System //I)
2. Sample cities (See System #2)
3. Request service (See System #3)
4. Five year redesign
D. Computation (See Systems #1, #2 and #3)
1. Test
2. Calculation
3. Printing
E. Reproduction & Distribution
(See Systems #1, #2 and #3)
1. Reproduction
2. Mailing and handling
F. Administration
1. Administrative director
2. Clerical help
3. Supplies & equipment (misc.)
First Cost
(Also First Year)
Hours
Dollars
1,363,750
12,000
21,600
14,675
27,500
8,225
18,000
77,000
74,375
24,000
52,500
88,125
9,375
41,000
22,000
40,000
66,000
4,000
Annual Cost
Hours
Dollars
853,500
20,000
21,600
14,675
6,625
8,225
6,000
9,750
9,750
88,125
9,375
41,000
22,000
40,000
66,000
4,000
Total
Ten Year Total
1,940,125 1,220,625
12,949,750
NOTE: All costs are estimated at +2.0% of the values shown.
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COST ESTIMATES
PILOT SYSTEM
Cost Factor
A. Data Gathering
1. Sample cities (10 cities)
2. Data from other sources
B. Data Processing
C. Computer Programming
1. Systems analysis &
computer programming
D. Computation
E. Reproduction & Distribution
F. Administration
1. Administrative director
2. Clerical help
3. Supplies & equipment (misc.)
First Cost
(Also First Year)
Hours
Dollars
275,000
12,000
15,000
30,000
20,000
2,000
40,000
24,000
1,000
Annual
Hours
Cost
Dollars
170,000
20,000
6,000
30,000
10,000
2,000
40,000
24,000
1,000
Total
Four Year Total
419,000
1,328,000
303,000
NOTE: All costs are estimated at +20% of the values shown.
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SECTION VII
APPENDIX C
SAMPLING OF REFUSE COMPOSITION
The sampling of refuse and of incinerator residue is an area of study where
little work has been accomplished. Refuse chemical composition and heating
value are significant parameters in incinerator design. Both influence the
design and capacity of furnace enclosures, grates, air and exhaust gas
fans, ducts, spray systems, controls, air pollution control equipment,
stacks, storage pits, and cooling equipment. Significant underestimation of
these characteristics can result in serious capacity limitations of incinerator
systems, leading potentially to early saturation of facilities, over-
temperature in furnace enclosures, insufficient furnace draft, and other
similar difficulties. Overestimation can lead to excessive furnace volumes
and difficulties in maintaining proper combustion, not to mention unnecessarily
high costs of construction. Residue sampling is important to assure that
putrescible content is below acceptable maximums and to provide a measure
of incinerator performance in terms of extent of removal of combustible
content. A current program has this under study.
Refuse or residue sampling is a difficult procedure. Extreme errors are
possible under even the best conditions. It is an expensive procedure, and
usually an insufficient number of tests are accomplished to assure that
experimental, day-to-day and seasonal variations are accounted for.
Refuse as delivered to a municipal disposal site is a heterogeneous mixture
including garbage, cardboard, paper, metal, glass, wood, plastic, etc.,
whose make-up can vary markedly from day-to-day, depending upon point of
origin, weather conditions, time of year, climate, etc. A sampling procedure
usually involves the systematic reduction of about 1,000 pounds to a finely
ground quart jar sample for laboratory analysis.
Between these extremes lies several steps of quartering and grinding until
the refuse particle size is quite small. Extreme care is taken to account
for original moisture content during the entire procedure, and it is a
testimonial to the patience and technique of some researchers » ^' ^> ^ that
any meaningful data has become available at all. Similar procedures are
required in analyzing incinerator residue. It is a procedure whose cost
precludes its application in the design stages of most cities' incinerator
programs, and consultants usually apply the "broad average" suggested by
the available research findings. Serious reductions in design capacity can
result if the local refuse is markedly different from the "average".
Another consideration with respect to refuse sampling is the variation of
the characteristics with time. The combustible content and the heating
value of municipal refuse have increased steadily over the last ten to
fifteen years, and this increase is continuing. When the "broad average"
data is applied in design, it is usually today's average, and potential
increases with time are generally ignored. In an incinerator plant designed
for a twenty to thirty year life, it would be logical to plan for some
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variation in the fuel. The incinerator operator is primarily interested
in the tonnage of material to be effectively burned. The fact that the
furnace still handles the same number of Btu/hour it did ten years ago is
small consolation if capacity has been reduced by 25 percent.
Thus, refuse sampling on a consistent cyclic basis could provide valuable
historical data which is sorely needed for more precise incinerator design.
Unfortunately, it is an expensive and tedious procedure which requires a
high level of skill, and which will be difficult to standardize for wide-
spread application. The representation of a great many tons of material by
a very small prepared sample leaves the procedure open to potentially large
errors.
There is a concept of sampling the characteristics of refuse and residue
which overcomes some of the difficulties of this potentially large error.
This technique would not require refuse sample preparations at all, but
would handle refuse "as delivered". The proposed technique would utilize
an entire incinerator as a test container. This incinerator would be
specially instrumented to provide highly accurate heat and mass balances.
With knowledge of the weights of incoming refuse, air and water, and of
outgoing flue gas, residue and water, along with flue gas analysis, the refuse
chemical composition could be calculated. By careful measurements of the
temperatures of all incoming and outgoing materials and by minimizing
and accounting for the heat losses, the refuse heating value can also be
calculated. This approach has been suggested and is actually under develop-
ment in Germany. In addition to doing away with the need for sample
preparation, the equipment need not be portable and can, therefore, be
built more ruggedly and accurately. The data can be automatically logged
and stored in a small computer for daily or weekly averaging of results as
desired. An incinerator such as this, centrally located within a region,
can either be statistically representative of the region, or can be used
as a sampling station to which various communities could deliver a substantial
sample of their refuse.
Selective sampling, using this concept, accomplished four times yearly to
account for seasonal variations, could provide participating communities with
precise data on which to base future incinerator designs. Although the
test incinerator construction (or conversion) would require special attention
to instrumentation and controls, and would require a larger and more highly
skilled staff, the overall costs would be less than the "conventional"
sampling techniques, and the data would be more reliable. When not being
used for testing purposes, this incinerator could be used for normal refuse
incineration by the community in which it is located.
Other refuse and residue characteristics are also of sufficient interest
to warrant sampling. These are fortunately less difficult to measure, and
the availability of data on them over a period of time is also important in
the economical design of equipment and facilities. Examples of these
characteristics include density and compactibility (both by compressipn
equipment and in land fills). These factors assist in the design and
selection of packer collection trucks and in the planning and acquisition
of land for sanitary land fills.
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Refuse and residue composition sampling is not recommended for initial
inclusion in any of the information system concepts discussed in Section V-C
The basic information which can be developed from accurate measurements of
refuse quantities and land consumption is initially more important. A
widespread program to incorporate standardized refuse and residue sampling
could be prohibitively expensive with little guarantee of success. Such a
program could be considered as a later phase of an information system.
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SECTION VII
APPENDIX D
STATISTICAL SAMPLING OF MUNICIPAL REFUSE DATA
A. INTRODUCTION
Decision making requires a steady supply of up-to-date information,
and information requires a continuous flow of accurate, reliable and
representative data. In the municipal solid waste field this is almost
totally lacking. There is no consistency to the gathering of data. Some
communities are quite diligent regardless of their size, while some
large communities are totally negligent. Data gathering techniques and
equipment are not standardized, and even the data that is gathered is
unavailable for any but the most minimal distribution. Even if this
data were available, there is little likelihood that it would be
representative of large populations and areas. It is apparent that any
decision making information developed from this inadequate data pool
can lead to poor decisions.
Statistics has repeatedly been proven to offer a means to represent the
characteristics of large populations or areas by relatively small samples,
if the samples are obtained under closely controlled conditions. The
problems of data gathering in the municipal solid waste field are no
less amenable to this approach, and it is proposed that trend predictions
of significant solid waste parameters be developed for the entire
United States and regions thereof on the basis of a relatively small
number of "sample cities".
The cities would institute a rigorous data gathering, recording and
reporting program, regardless of their current level of solid waste
activity. Weighing scales would be installed, and all solid waste
generated within the community would be weighed. Its source would be
noted whether commercial, industrial or residential, and its disposition
also recorded. Land fill consumption, refuse densities and compactibilities,
etc. would also be measured periodically. The data gathering system in
each city would be designed to issue reports to a. central administrative
agency on a sufficiently frequent basis to assure that seasonal and
climatic variations are accounted for.
The techniques to be applied in the selection of the parameters to be
measured and the number and location of the cities is discussed in the
sections to follow.
B. FACTORS SIGNIFICANTLY INFLUENCING SOLID WASTE PARAMETERS
In attempting to develop a means for selecting the number and location
of sample cities, the factors which significantly influence the solid
waste parameter under consideration must be determined. Per capita
generation will be used as an example, but the technique would apply to
any of the parameters. The calculation of the generation of refuse in
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pounds per capita per day, requires the gathering of refuse weight
data and the availability of current population data.
For municipal refuse generation in pounds per capita per day, the
influencing factors in a given city might be:
1. Population of the city.
2. Per capita income, or other economic indicator.
3. Zoning complexion; i.e. residential versus industrial, etc.
4. Climate and seasonal effects; i.e. north, south, etc.
5. General community complexion; i.e. urban versus rural, etc.
6. Policy with regard to industrial waste; i.e. accept it at the disposal
site or not.
Additional factors certainly exist; these six are some of the apparent
ones influencing per capita generation. Other parameters may have
larger numbers of influencing factors. The above six are probably
expandable into ten or more possible factors which give a "Yes", "No"
alternative. The next step would be to determine which, either singly
or in combination, most significantly influence the per capita generation.
C. RELATIONSHIPS AMONG VARIABLES
If a test were to be attempted for each potential combination, then the
number of cities in which testing would be established would be given
by the formula:
S = 2n
where:
S is the number of tests
n is the number of sources of variation
If a total of ten influences were to be studied,
S = 210 = 1024
That is, 1024 separate cities would have to be tested, if that many
could be found which have the required combinations of factors.
Sometimes the factors have a stronger influence acting in combination
than when acting singly. This would lead to an upward revision of the
list of the sources of variation, and further, more involved study.
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Except in the most simple cases, complete study of all combinations is
impractical and a sampling approach must be taken. Generally, the number
of samples should, at a minimum equal the number of influencing factors,
and two to one is a good design ratio. Thus, for example, if there
are fifteen influencing factors, then a sample of thirty tests is indicated
The combinations of the influencing factors, or sources of variation,
for each of the thirty tests is determined in a random fashion, but with
a balance in the sources of variation. That is, if one of the sources
is, for example, urban versus rural characteristics, the random selection
should result in fifteen cities with an urban characteristic and fifteen
with a rural characteristic. Randomized adjustment is continued until
balance is achieved in each case. Table VII gives an example of this
procedure.
The procedure involves the use of a table of random numbers. Using the
North and South (N versus S) source of variation, the N is assigned odd
numbers s the S even numbers. The first tabulation results in 10 N and
20 S. The table is then searched for random numbers between 1 and 30,
finding those numbers which correspond to excess N's and changing those
to S's, until the 5 excess N's have been changed to S's, as indicated, to
balance the choices. This procedure is repeated for all sources of
variation. The result gives a random combination of characteristics
for any of the test cities.
Thus, referring to Table VII, test city number 5 will have a southern
climate characteristic, will be economically rich with an urban
character, etc., for the other influences.
The output of per capita refuse generation developed from the data taken
in each sample city will then be subjected to linear or curvilinear
multiple regression analysis according to the following equation:
where :
Y = a0 + a-^ + b2X2 + ..... + tSy
Y is the variable of interest; in this case, the per
capita municipal refuse generation.
a0, a^, b2, etc. are the regression coefficients.
X-,, Xo , etc. are the sources of variation. There can
be combinations of other variables; for example,
X3 = X^ x X^ ; or powers of other variables; for example,
X3 = (X4)2
S is the standard error of the estimate.
t is the multiplier which provides various levels of
confidence that the regression equation provides a true
measure of the variability in Y.
-108-
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TABLE VII
Test No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Total
Adjusted
Total
North or
South
(N or S)
N
N
N
S
S
N
S
S
N
N
N
S
S
S
S
N
S
N
S
N
S
N
N
S
S
S
10 N
20 S
15 N
15 S
Rich or
Poor
(R or P)
R
P
P
R
R
R
R
P
R
R
P
P
P
R
R
P
R
P
R
P
P
R
P
R
R
P
P
P
R
P
15R
15P
Industrial
o_r
Residential
(I or R)
I
R
*R
R
I
R
I
I
R
R
R
I
I
I
R
I
I
I
R
R
R
I
R
I
R
I
R
I
I
R
16 I
14 R
15 I
15 R
(U or R)
R
U
U
{(U
R
U
R
R
U
R
R
R
R
jtU
R
U
R
U
R
U
U
U
R
R
U
U
U
R
R
U
18 R
12 U
15 R
15 U
etc.
etc,
-109-
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Note that the equation may include various combinations of the influencing
factors. The form of these combinations is largely a matter of
intuitive feel and mathematical experimentation. If a sufficiently
small number of factors are under consideration, all possible inter-
actions may be included at the outset. This is not usually the case,
however, and judgment must be applied.
The standard error of the estimate is a good measure of how well the
selected sources of variation and their selected combinations have
accounted for all variation. The usually applied criterion is the
correlation coefficient, R, which is related to the standard error as
follows:
y
where:
ay is the standard deviation of y
A typical criterion for the correlation coefficient is that
R = .89.
= .80 or
Often the initial number of samples is made smaller than the total
expected and additional samples are added sequentially to increase the
correlation coefficient. The regression equation would be used to
calculate, in the example, the expected per capita generation for all
possible combinations. Then the high and the low values would be pin-
pointed, and sample cities found to actually account for these combinations,
The choosing of the high and low values provides the most powerful means
to increase the correlation coefficient. This is illustrated by
Figure 15.
Additional
Test Points
o o
o°°o°
0°00
o
X
Figure 15
If the bulk of data
is clustered as
shown, choosing two
additional test
points as indicated
is more significant
than two more "in
the bunch".
-110-
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The procedure would continue until the desired level of correlation
coefficient was obtained, or until the allotted number of samples were
exhausted. Once the regression equation is established, the standard
error of the estimate would then be evaluated as if it was acceptable.^
The size of the error incurred by using it to represent the true ^relation
ship between the per capita generation and the sources of variation is
a function of the level of confidence desired in using the equation:
y = a0 + a^ + b2X2 + ...... ±tsy
If:
t = 1, then the confidence is 68.26 percent
t = 2, then the confidence is 95.45 percent
t = 3, then the confidence is 99.37 percent
t = 4, then the confidence is 99.99 percent
Thus, a 95 percent confidence gives an error which is double the standard
error.
Upon examination of the final equation, the combinations of certain of
the coefficients a^, b2> etc. and their corresponding variables, will be
seen to be quite small, which means that their influence is negligible.
They may be dropped and the remaining equation used, although the
standard error will increase somewhat. In addition, variables may be
dropped if the standard error of the coefficient exceeds twice the
coefficient itself. In this case, coefficients will be selected for a
confidence level of 95 percent. The elimination of certain influences
will, in some cases, simplify the data gathering procedures and simplify
the selection of further sample cities. It may even be possible to
achieve desired results before all samples are obtained.
D. TIME-DEPENDENT RELATIONSHIPS AMONG VARIABLES
The primary output of a basic information system for municipal solid
waste would be the predictions of time-based trends in various solid
waste parameters, such as the per capita generation used in the example.
Thus, data must be collected on a continuous basis. Several years'
data must be gathered to permit the trends to be developed. The basic
regression equation technique is still applicable, except that the time
variable, 0, is added to the equation. It may be that the' influence of
the other sources of variation is not time-based, and the annual regression
equation will simplify to a single variable in time. That is:
y(t) = a0 + 1^(0) + t Sy
Generally, data at two points in time is required to establish a linear
trend and three points for a curvilinear trend; however, these are
minimums when the time intervals are relatively large. For yearly data
additional points are required, and four to five years is a reasonable
figure. The remarks regarding the level of confidence in the time-based
line apply for the historical data only. The confidence in the
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extrapolation of the regression line into the future is not given by the
regression analysis. The longer the time periods used to project into
the future, the less accurate the prediction is. On the other hand, the
more data used to develop the regression line, the better the accuracy.
GENERAL REMARKS
The size of the sample, or the number of sample cities to be established,
if the results are to be typical of the entire nation, should probably
be about thirty. If the nation is arbitrarily regionalized, such as into
the nine Public Health Service regions, more than thirty would probably
be required, if a reasonable sample is to be established in each region.
The regression analysis will determine the extent of the influence of
geographic and climatic considerations, and the need for regionalization
could await these initial results. Since sequential addition of samples
may be considered in any event, further cities could be added to round
out the regions as desired.
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technical-economic oueruiew
(volome iu)
-------
INTRODUCTION TO VOLUME IV - TECHNICAL - ECONOMIC OVERVIEW
This volume is part of a four volume report. The other volumes are:
Volume I - Municipal Inventory
Volume II - Industrial Inventory
Volume III - Information System
Volume IV has nine parts. Part 1, LANDFILL OPERATIONS, was obtained
primarily from a review of the literature and selected interviews. The
report was reviewed by qualified people in the field.
Part 2, COMPOSTING, was based on personal interviews and a review of the
literature. This report was also reviewed by a consultant with many
years of experience in composting practices.
Part 3, APARTMENT HOUSE INCINERATORS, was prepared by a consultant who for
the past several years, until his recent retirement, was a member of the
New York City Department of Air Pollution Control.
Part 4, A REVIEW OF THE STATE OF THE ART OF MODERN MUNICIPAL INCINERATION
SYSTEM EQUIPMENT, was prepared by Combustion Engineering personnel and is
based on personal interviews, plant visits, and Combustion Engineering's
extensive experience in this field.
Part 5, INCINERATOR AIR POLLUTION CONTROL EQUIPMENT, is based on Combustion
Engineering experience; equipment costs were based in part on quotes from
vendors of air pollution control equipment.
Part 6, POTENTIAL ENERGY CONVERSION ASPECTS OF REFUSE, gives some technological
trends in municipal burning systems.
Part 7, THE EFFECTS OF MUNICIPAL REFUSE VARIABILITY ON INCINERATOR EXHAUST
GAS, WATER AND AIR FLOWS AND BURNING CAPACITY, is an original analytical
computer study which indicates how changes in refuse composition affect
the design and performance of municipal burning systems.
Part 8, THE COSTS OF CONVEYING SOLID WASTES BY RAIL, was prepared by
Dr. Louis Koenig of Louis Koenig Research, San Antonio, Texas. Dr. Koenig
conducted the study under a sub-contract to Combustion Engineering.
Part 9, MUNICIPAL BUYING PRACTICES, presents the industry - municipality
relationships as they exist today when municipalities purchase burning
systems.
The material in this volume was prepared by Combustion Engineering personnel
and outside consultants. The individual authors are given at the beginning
of each part. Mr. Elliot D. Ranard served as Program Manager for Combustion
Engineering; Mr. Ralph J. Black served as Project Director for the Public
Health Service.
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PART 1
LANDFILL OPERATIONS
Prepared by
James E. Seibel '
Product Analyst
Product Diversification Department
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. SANITARY LANDFILL
A. INTRODUCTION l
B. BENEFITS !
C. OPERATIONS 1
D. POTENTIAL PROBLEMS 4
E. COSTS 6
F. ADVANTAGES AND DISADVANTAGES 7
II. OPEN TRENCH BURNING
A. SINGLE LIFT FILL 9
B. TRENCH FILL 9
C. CANYON FILL 9
D. LAND REQUIREMENTS 9
E. SEGREGATION OF REFUSE 10
F. BURNING PROCEDURE 11
G. ADVANTAGES U
H. DISADVANTAGES 12
III. COMPACTING
A. ON-SITE COMPACTORS 13
B. COLLECTION OF REFUSE 15
C. DISPOSAL SITE COMPACTORS 15
IV. REFERENCES 16
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SECTION I
SANITARY LANDFILL
A. INTRODUCTION
As defined by the American Society of Civil Engineers, "sanitary
landfill is a method of disposing of refuse on land without creating
nuisances or hazards to public health or safety, by utilizing the
principles of engineering to confine the refuse to the smallest
practical area, to reduce it to the smallest practical volume, and to
cover it with a layer of earth at the conclusion of each day's
operation or at such more frequent intervals as may be necessary".!
Sanitary landfills were first used in England in 1916 where the process
was called "controlled tipping". Around the 1930's, New York City and
Fresno, California were the first communities to try it in this country.
Early successes prompted many other communities to adopt this method
of refuse disposal. By the end of 1945, 100 cities were using this
process. By 1960, 1,400 cities had begun to use it.^ Sanitary land-
fills absorbed less than 10 percent of the refuse collected in early
postwar years. They now account for just under 50 percent of the refuse
collected.-^
B. BENEFITS
In the last thirty years, thousands of acres of worthless and low
value land have been improved to the point where they are now being
used for parks, playgrounds, parking areas and other useful facilities.
In fact, were it not for sanitary landfill, parts of the nation's two
largest cities, New York and Chicago, would not even exist today. In
New York's five boroughs, landfills created bathing beaches, water-
front parks, marinas and redeemed land for expressways. In Chicago,
much of the famous lakefront was created by carefully planned landfill.^
Completed sanitary landfill sites are currently being used for parking
lots, parks, playgrounds, golf courses and all other types of recreational
areas. Construction of buildings has, for the most part, been con-
fined to light structures. In some areas, better growth of plant life
is obtained than the original ground surface would support.^ Depending
on root depth, even trees can be planted.
C. OPERATIONS
Landfill sites fall into one of two major classifications: (1) area
landfills, which comprise sites on primarily flat land such as marsh
land, tideland or marginal lowland; (2) depression landfills, which
comprise sites that utilize natural or man-made depressions or
irregularities in the terrain such as quarries, sand and gravel pits.
The "area landfill" classification is further sub-divided into categories
according to method of operation. Three of the most practical methods
used are progressive excavation, cut and cover and imported cover method.^
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1. AREA LANDFILL
a. PROGRESSIVE EXCAVATION
The simple continuity of the progressive excavation method is
its most distinguishing feature. Cover material is excavated
directly in front of the working face and is placed directly
on the previously compacted fill. The cover is excavated only
as needed to properly cover the fill material. This type of
landfill is usually serviced by bulldozers or clam-shell
machines and utilizes a ramp type working face. Draglines are
sometimes used to operate a trench-type progressive excavation.
In a ramp type project, it is easier to see the work and control
the spreading of the refuse if it is discharged at the base
of the working face and spread from the bottom up. This method
of operation also has the tendency to screen the operation from
the public view and minimize the nuisance of blowing paper.6
b. CUT AND COVER
When the material excavated from a trench is stockpiled adjacent
to the site and later used for cover over the compacted refuse,
the operation is called a "cut and cover" type of area fill.
In some cases, the excavated material may exceed the require-
ments for the cover needed and the extra material is sold. The
rate of excavation bears no relation to the rate of refuse
disposal and in many cases long parallel trenches are opened
considerably in advance of the need for refuse disposal.
This is sometimes a big advantage where there is excessive
rainfall or the ground may become frozen in the winter.
The cut and cover method for operating an area fill is well
suited to sites where excavation may be made below the water
table. A dragline is essential in an operation of this type
and the refuse is discharged at the top of the working face.
The dragline may be used to spread and compact the refuse.
c. IMPORTED CO_VER
The imported cover type of landfill is used when depressed
areas of land are available but sufficient cover cannot be
secured at the site. Fills in rock quarry pits are a good
example. The refuse is placed and compacted by a bulldozer or
dragline as in other types of landfill. Cover material is
usually stockpiled or delivered as needed to the site. Waste
sand from nearby gravel mining operations and earth from building
site excavations or from highway excavations are a common
source of cover material.
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2. DEPRESSION LANDFILLS
In depression fills the total depth of refuse generally exceeds
the depth for a single layer of lift operation. Each stratum or
lift is constructed by the placing and compacting of the refuse
so that cells are constructed, with fill material on all sides
to prevent travel of fire through the mass and for the control of
rodents, flies and odors.
Pit and quarry sites are normally used for depression landfill
operations. The distinguishing characteristic of all pit and
quarry sites is that they are lower at all points than the
surrounding terrain. The pits are usually of such a depth that
several lifts or strata are necessary to bring them to grade. If
there is available cover material and no drainage problems are
created, there is no reason why the area may not be filled to a
level much higher than the original ground, particularly if the
area was originally characterized by rough terrain.
Refuse is transported to the working face by way of access roads.
If compaction is done by bulldozing from the bottom up in sloping
layers, a high density can be achieved. Maximum capacity can also
be secured because the weight of several lifts will help create a
greater density than would normally be achieved in a cut and
cover area landfill. It may be advisable to operate the first lift
by the progressive excavation method of landfill. The fill should
be above the ground water level unless it can be shown that any
pollution of the ground water will not adversely affect adjacent
areas.
It is important that the pit and quarry sites include enough
suitable excavatable cover material around their perimeters or
that there is enough overburden and non-marketable materials
available on the site to provide a volume of cover equaling at
least 25 percent of the refuse."
Sanitary landfills must be first class operations. Facts and plans
will do most to insure acceptance a carefully thought-out master
plan which will illustrate the potential benefit to the community
is needed. These plans must be flexible to accommodate changes in
real estate development. Cooperation of cities and counties as
well as their respective departments is a must.4 Municipalities or
contractors should select and buy land in advance for future
disposal needs. It is important that the land deed state that the
area will be used as a refuse disposal site for a specified number
of years. Thus forewarned, housing developers and citizens can
plan accordingly.
The American Public Works Association Research Foundation has pre-
pared a method for determining "landfill area required". The formula
used is as follows:
v = FR (1 - P }
D 100
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where:
V = Landfill volume in cubic yards required for refuse disposal
per capita per year.
F = A factor which incorporates the cover material, averaging
17 percent for deep fills and 33 percent for shallow fills
with corresponding F values of 1.17 and 1.33.
R = Amount of refuse contributed in pounds per capita per year.
D = Average density of refuse in pounds per cubic yard delivered
at the landfill (about 325 for collection by compactor trucks).
P = Percent reduction of refuse volume in the landfill, varying
from zero to 70 percent.
D. POTENTIAL PROBLEMS
There are several problems that can arise at sanitary landfill sites.
The most significant include the following:
1. WATER POLLUTION
A principal hazard of sanitary landfill disposal is the possibility
of fluids leaching from the fill and polluting the streams. Such
problems can be minimized, or prevented, by constructing the fill
in such a manner that it does not become saturated. This can be
accomplished by filling all space below maximum ground water
level with inert material, providing an impervious dike around the
fill to exclude flood waters or surface drainage from adjacent
higher ground, and covering and grading the top of the fill to
drain off much of the precipitation which falls on its surface.'
Studies have also been conducted to determine the risk to ground
water from refuse tipped into dry and wet pits.8
Besides the problem of ground water pollution, the filling of
swamps of flood plain lands can have an adverse effect upon flood
conditions. Flood control is essentially a space allocation
problem, and under natural conditions flood plains and swamps
provide natural channel storage areas for surplus water. If these
areas are filled, they are no longer available for flood water
storage, and space needed to accommodate flood waters can be
obtained only by raising flood stages. In addition, enroachment in
the channel cross-section reduces hydraulic efficiency of the water-
way and may cause it to back up behind the constriction. Although
the use of sanitary landfills is sometimes extolled as a desirable
way to "reclaim flood plain areas", care must be exercised to see
that the operations are properly designed and located so that they
will not cause adverse effects on flood stages.^
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2. GASES
The amounts of gas produced seem to be directly proportional to
moisture content of the fill. Temperatures and climatic conditions
are also factors. No way has yet been found to prevent methane
gas production in sanitary landfills.2 Odorous gases, particularly
hydrogen sulfide gas, have been noticed in sites where contractors
have disposed of gypsum board and similar building materials
having a sulfate content. This is a result of the formation of
hydrogen sulfide by the action of sulfate-reducing bacteria on
these materials.^ An incident in a Chicago landfill which was
completed twenty-five to thirty years ago illustrates the extent
of gas production and danger. The sanitary landfill site was
covered with two feet of snow, sealing the natural openings through
which the gas normally escapes. The result was to force the gas
into sewers serving homes in the area, causing an explosion.
3. FLYS AND RODENTS
Fly and rodent control is a problem in any landfill operation.
Fly control is best accomplished by using a cover material with a
binder which is well compacted. A well compacted cover of 2 5/8
inch prevents fly emergence. With an uncompacted earth fill of
5 foot thickness, 90 percent fly emergence has been noted.
Covering the refuse every night eliminates the attraction of
rodents. ^
4. FIRES
Landfill fires also present significant control problems. Fires
can be controlled by proper supervision of personnel and dumping
procedures. Minimum amounts of area should be open at one time
to prevent wide spread of fires. Watering down of refuse tends to
reduce possibility of fire while at the same time aiding com-
pacting.2
5. DECOMPOSITION
Studies on factors which affect the rate of decomposition of
organic matter in sanitary landfills have been made in several
areas. These factors include moisture, soil mixture, depth of
fill, type of soil, aeration and temperature. In Los Angeles
County, such factors prevent decomposition of refuse in landfills.
However, in Seattle, Washington where there is heavy rainfall,
decomposition does take place.2 More investigation is needed to
determine the effects of moisture and seasonal changes on decom-
position.
In a landfill site near Chicago, after seven years, a sanitary
landfill site was excavated and almost complete deterioration of
material was noted. This material made excellent cover and supported
the growth of grass. It was an excellent soil additive. Even
-5-
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material buried only four years showed considerable decomposition
and a low moisture content. The sites were on an old lake bed,
but the fill itself was considerably above ground level.2
Whether decomposition is desirable or not must to some extent
depend on what future use is planned for the site.
E. COSTS
Costs of sanitary landfill method for refuse disposal cover a wide range,
The total cost includes the land cost plus site development plus
operating and equipment costs. Since the land should increase in
value, even in a remote area, the cost of the land from a long range
point of view is sometimes neglected.
Data obtained in 1954 showed that the total cost of plant and equip-
ment required for sanitary landfill for a community of 10,000 persons
was approximately $8,000, for a community of 50,000 persons $20,000,
and for 90,000 persons $25,000.^ More recently, there is almost
unanimous agreement that costs will usually range from $.80 to' $1.50
per ton. A cursory evaluation of landfill costs yields the following
equation (not including transportation costs) .-*-
$/ton = .50 + 6,000
tons per year
Transportation costs need to be added to operating and equipment
costs to obtain total cost per ton. There are two methods of
figuring transportation costs. The better method is based on hauling
time; the second method is based on mileage.
The first method of figuring costs is the "ton minute". The unit
cost of "ton minute" is arrived at by dividing the dollar cost per
minute by the net tons on the load. It does not matter whether the
vehicle travels 15 miles per hour on surface streets or 60 miles per
hour on the freeway. What does matter is the length of time the trip
requires, since the vehicle is being paid for on a time basis rather
than mileage base. The cost of any direct haul vehicle can be
represented on a graph. A line drawn through the origin with a slope
equal to the cost per ton per minute represents the cost for hauling a
ton for any length of time.
The hauling time method is also helpful in determining when a transfer
station type of operation is economic. In any transfer operation, the
cost of owning and operating the station itself is not productive of
moving refuse to the place of final disposal. This cost must be
"earned back" by the greater efficiency of the haul vehicle being used.
There also might be other unproductive expense at the disposal site,
since the transfer vehicle will quite likely be less maneuverable,
require the removal of covering tarpaulins, and may require a longer
time to unload than a collection vehicle.-'--'
-------
The second and older method is based on cost/ton/mile, i.e.,
ISC/ton/mile, 30c/ton/mile. These costs are based on average speeds
of 15 miles per hour on city streets and 45 miles per hour on free-
ways, full operating, maintenance, and depreciation cost of equipment,
labor costs including fringe benefits and overheads.^ Adding to
these figures a cost of $1 per ton for dumping, and assuming a ten
mile haul distance from collection route to dump, the total cost per
ton would come to: twenty miles at $.15 = $3 plus $1 or $4 per ton
total cost.
F. ADVANTAGES AND DISADVANTAGES
The advantages of sanitary landfill over other solid waste disposal
methods are:
1. Less capital investment.
2. Can accommodate peak refuse quantities readily.
3. Combined refuse collection, including garbage, ashes, combustible
rubbish and non-combustible rubbish is possible thus reducing
collection, costs.
4. Operations can easily be terminated without a great loss in equip-
ment or land. The equipment is of a type which can readily be
used for other municipal functions and the land at any stage is
no worse, and usually is better than it was before the operation
began.
5. Sanitary landfill requires less land than open dumping because
the refuse is compacted to between 40 percent and 50 percent of its
original volume and can be deposited to a greater depth by digging
ditches. Approximately one acre per year is required for 10,000
persons (seven acre feet)-
6. Unusual materials and bulky articles do not usually cause
difficulties of operations.
7. Sanitary landfill can be established immediately upon the purchase
or rental of standard digging and compacting equipment and
authorization to use the land. No plant has to be built before
operations can begin as is true of other solid waste reduction
methods.
The disadvantages of sanitary landfill are:
1. Large amounts of land are required,
2. Sites located outside of a city are usually under some other
Governmental jurisdiction.
3. Winter operations present difficulties.
-7-
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4. Prevention of ground water pollution may be costly.
5. If the distance to the sanitary landfill site is very great, the
cost of transfer operations may be high.
Additional information sources on landfill operations are avail-
able. I*. 15, 16
-------
SECTION II
OPEN TRENCH BURNING
The burning of refuse at dumps is commonly considered to be an undesirable
practice. Smoke and other air contaminants normally emitted cause
nuisances in nearby developed areas and contribute to the community-wide
air pollution problem. As a result, dump burning is being prohibited by
air pollution control legislation in populated sections of many states.
However, controlled burning methods are being used in some locations which
avoid some of the undesirable features commonly associated with dump
burning. Such methods are not a "cure all" that would make it possible to
establish burning sites in or very near populated areas. These practices,
however, can reduce the amount of smoke produced with little additional
cost. Also, they may furnish an interim solution to the refuse disposal
problem even in areas where burning may ultimately be prohibited for air
pollution control reasons. '
The three types of controlled burning dumps used reflect the influence
of the topography of the site selected. They are the single lift fill,
the trench fill, and the canyon fill.
A. SINGLE LIFT FILL
The single lift fill is used where level low ground can be improved
by filling. Roadways and a bank with a safety berm are constructed
so that the completed fill will fit the contours of the surrounding
land.
B. TRENCH FILL
The trench fill is constructed by excavating a trench in level ground.
It is operated as if it were two single lift fills facing each other.
The excavated material can be used to cover the completed fill or to
provide fill material for other work. The cost of excavating the
trench makes this type of operation slightly more expensive than the
other two.
C. CANYON FILL
In a canyon site, conditions similar to the single lift fill can be
created by cutting two shelves along the side of the canyon. The upper
shelf is maintained for burning by occasionally bulldozing the ashes
down to the lower shelf where they create a solid and permanent fill.
The main purpose of the lower shelf is to limit the dumping area and
facilitate salvage. Burning is confined to the upper shelf.
D. LAND REQUIREMENTS
Conveniently located marginal land can often be found that is suitable
for the establishment of one of these types of controlled burning
dumps. Regardless of the terrain, there are five requirements to consider,
-9-
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1. Sufficient isolation so that surrounding residents will not be
affected.
2. Caretaker (full time preferably) to supervise the dumping and
police the operation.
3. Clean level roadways and a safety berm for trucks and cars to
back up against. Together with good housekeeping, these encourage
the cooperation of the public in dumping over the bank.
4. A bank approximately 15 feet high with a 45 degree slope to cause
the load dumped for a collection truck to properly loosen and
scatter down the bank. This procedure allows enough air to get
to the refuse for efficient combustion.
5. Sufficient length of dump face for proper segregation of materials.
Trench fills or single lift fills on low ground should be so located
that no portion of the fill intercepts ground water. Problems of
water pollution, stuck equipment, and difficulties in removing salvage
are common in marshy areas. Provisions must be made for handling
drainage water from the fill and roads, as well as any surface water
that normally flows thro'ugh the site. A slope of one to two percent
is sufficient to prevent difficulties on the roadways and in the
trenches. Access roads should be constructed so that they are pass-
able throughout the year. Fire breaks must be carefully constructed
and maintained to prevent the spread of fire to surrounding property.
E. SEGREGATION OF REFUSE
Separation reduces objectionable smoke and odors, and permits maximum
salvage. By providing separate areas for dumping, it is usually
possible to accomplish a great deal of segregation as dumping proceeds.
When the people using the site have become accustomed to the system,
signs alone may be sufficient. The degree to which segregation is
carried must be fitted to the area in which the dump is operated and
the degree of perfection that is required. The following separation
into five classes of materials has been successfully used in a number
of operations.
1. Household rubbish, mixed refuse, paper, cardboard cartons, cans,
bottles, toys, and similar materials. After the non-ferrous
materials are salvaged, the remaining refuse can be burned daily
with almost no smoke. The tin cans and other ferrous metals can
be periodically salvaged by using a mobile crane and electromagnet.
With salvage of cans, the useful life of the trenches can be
extended significantly over their life without salvage.
2. Stoves, refrigerators, washers, tanks, drums, beds, and other
large items. These items are almost totally salvable and should
be kept separate to conserve space.
-10-
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3. Tires, ground rubber, roofing paper, linoleum, other heavy smoke
producing materials, such as concrete and bricks. Salvageable
items can be removed and the remaining material buried without
burning. If these heavy smoke producing materials must be burned,
particular attention should be paid to selecting a time when
atmospheric conditions are the most favorable to disperse the smoke,
4. Lawn clippings, brush and tree trimmings. These green materials
need to be thoroughly dried before burning or they will only
smolder. In order to avoid fly production in cases where large
quantities of green lawn clippings are received, they should be
buried immediately.
5. Dirt and ashes. By providing a separate storage area, dirt and
ashes can be saved for cover material.
F. BURNING PROCEDURE
When refuse is dumped in a pile and set afire, excessive amounts of
smoke are commonly produced. However, with little additional expense,
proper conditions for controlled burning can be established. Gravity
is utilized to do most of the work of loosening and scattering the
refuse on a properly constructed bank.
Usually the caretaker uses a long handled hook fork to finish breaking
open and spreading the dumped refuse. After the refuse is properly
spread, the fire is started on the downwind side. This keeps the
fire from smothering itself, and so results in a cleaner burn. At
the tail end of the burn, any matted material such as newspapers or
grass clippings, will have a tendency to smolder and produce smoke.
These matted materials are broken open at this time with a long handled
hook fork so that the air can get to them and complete the burning
quickly. When the burn is conducted in this manner, the refuse
spread out on the bank can get sufficient air for efficient combustion
and yet it is still concentrated enough to generate the necessary
temperature to sustain good combustion. The bed of cans and bottles
acts as a grate, allowing air to get underneath as well as around the
refuse. The time required for combustion of one truckload of refuse
is reduced from an hour or more to approximately 15 minutes. Also,
the amount of smoke produced is markedly reduced. Best results are
obtained when a maximum of four or five truckloads of refuse are burned
at one time.
G. ADVANTAGES
Controlled burning dumping Coffers the following advantages:
1. A minimum amount of land and equipment are required, thus minimizing
the capital investment.
2. Dump sites last longer.
-11-
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3. Proper bank slope and depth promote complete, clean, fast burning
with a minimum of smoke.
4. Maximum salvage of metals helps maintain the operations, conserves
dump space, reduces costs and conserves natural resources.
5. The final residue is held to an absolute minimum and the land
can be returned to immediate use.
6. The safety berm prevents accidents and encourages dumping over the
bank.
H. DISADVANTAGES
The disadvantages of controlled burning dumping are:
1. Some smoke and air contaminants are produced, so that an isolated
site is required.
2. Burning is a fire hazard to surrounding property.
3. Fly control is not as effective as at properly operated sanitary
landfills.
4. Public cooperation is necessary in separation.
5. Dead animals, swill, cannery wastes, wet manure, and other wet
wastes must be specially handled.
-12-
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SECTION III
COMPACTING
The compacting of refuse can occur at any or all three of the areas
involved in refuse disposal. Compacting units have been built for
on-site use. That is, at apartment buildings, schools, super markets,
institutions, etc. where large amounts of refuse are generated. The
collection of refuse today is largely made by collection vehicles with
compactor units. The final area of compacting is at the disposal site
where heavy equipment is run over the refuse or, as in the case of
North Tonawanda, New York, a special vehicle is used to provide compacting.
Compacting of refuse is easily accomplished by the machinery available
today. Hydraulic or pneumatic cylinders can exert forces as high as
90,000 pounds, reducing the original volume of the refuse by 60 to 80 per-
cent. However, refuse is not like scrap metal which retains its compacted
shape. Refuse must be restrained in its compacted shape by keeping it
under pressure, either by bagging, baling, or some other means.
A. ON-SITE COMPACTORS
There are several basic systems of on-site compaction. One is a
proprietary system which utilizes a pneumatic ram to compact the
refuse into paper sacks or plastic containers. The principle of
operation is relatively simple. The machine compressor and paper
bag holder are mounted below a refuse chute. As the refuse enters
the bag, it triggers a mechanism that shunts the bag under the
pneumatic ram, places a clean bag under the chute, compresses the
collected refuse and the partially filled bag stands ready to be
shunted back under the chute until full.
A four-bag machine, operating under high compaction pressures
(3,000 psig), would cost approximately $3,000, including the air
compressor unit.18Each bag will hold approximately 3.5 cubic feet of
refuse having a total weight of 75 pounds. The bags will cost
approximately twelve cents each. Therefore, for a typical 100 unit
apartment housing 250 people and assuming a waste generation rate of
2.25 pounds of refuse per capita per day, 560 pounds of refuse would
be generated each day. This amount could be handled by eight bags at
8 x 12 or 96C per day for bags.
The paper bag compactor has a number of significant advantages in
that it:
1. Provides a sanitary method of collection.
2. Reduces the volume to one-third of its original volume.
3. Produces refuse packages that are relatively easy to handle.
-13-
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4. Reduces the amount of on-site storage required.
5. Reduces the need for expensive compaction equipment on the
municipal collection vehicles.
The disadvantages are:
1. The requirement for a high-pressure (300 psig) storage vessel on
the premises.
2. The critical dependence on electrical energy.
3. The possibility of poorly manufactured paper bags of low strength.
As these systems are installed, it is possible that the relatively
high bag costs (12c) will stimulate the manufacture of cut-rate
bags.
4. Unknown system reliability and maintenance costs.
5. No reduction in weight of refuse.
The other system of compaction in general used today consists of a
horizontal ram and compression area connected to a wheeled detachable
container reportedly reduces the volume to about one-quarter of its
original volume.
The system is reported to cost approximately $4,500. When the
detachable container is fully loaded, a signal is energized and it will
not accept any additional refuse. The standard detachable container
will hold approximately 1,000 pounds of compacted refuse which then
can be wheeled to the area for municipal or private collection. It
has all of the advantages and disadvantages of the bag compactor
except for the size of the refuse container and several additional
disadvantages:
1. The location of the collection chutes must be controlled to make
sure that the loaded refuse container can be moved to outside
collection.
2. It requires modification of, or special types of municipal col-
lection vehicles.
3. Because of the size and weight of the detachable container, it
probably will require the services of at least two custodial
personnel if it must be removed to another location by the
collection truck.
There are also on the market a number of systems in which a heavy duty
crusher or disintegrator crushes or chews up the refuse. The crushed
or disintegrated refuse is then delivered to a baling machine where it
is wrapped and sealed for later pick-up. This type of system might
lend itself to a central station concept wherein refuse from a number
-14-
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of chutes is conveyed to a central station for compaction and baling.
In general, it has little application to a single multi-family unit.
B. COLLECTION OF REFUSE
Compactor type collection vehicles are used extensively throughout
the United States today. There are approximately thirty manufacturers
of these vehicles. At present, about three-quarters of all refuse
trucks in operation are of the compactor type, and virtually all
vehicles sold by 1980 will compact waste. Needs exist for a higher
ratio of payload to dead weight in such trucks today's models are
so big and heavy and compact materials so effectively, that they often
exceed legal weight limits when full. Another improvement needed is
some device or system that retains the compaction achieved in the truck.
At present the compressed material regains much of its bulk when
dumped, and must be recompressed at the landfill site. Trucks in
operation today can exert up to 90,000 pounds of force on the refuse
and compact 60 cubic yards or 10,000 pounds of refuse into a 20 cubic
yard truck.
C. DISPOSAL SITE COMPACTORS
Almost all compacting done at landfill sites is accomplished by
dragging a crane bucket (dragline method) over the refuse or running
over the refuse with a bulldozer. The amount of compaction obtained
would depend on the make-up of the refuse (moisture contejit), amount
of previous compaction either on-site or in collection, the number of
times the bulldozer runs over the refuse and the spring-back of the
refuse before it is finally covered with earth.
Another method has been developed for compacting and is currently
being used in North Tonawanda, New York. A large automated vehicle,
which has a compactor built into it, moves along the landfill site
digging a trench about 4 feet wide by 8 feet deep. It accepts truck-
loads of refuse, compacts the refuse and extrudes it into the trench.
While still under pressure, earth is filled in over the refuse as the
vehicle moves along so that the refuse has no opportunity to spring-back.
The manufacturers of this equipment claim that one machine of this
nature could service a town of 80,000 to 100,000 people. This machine
will be evaluated under a demonstration grant in Niagara County,
New York. The project is expected to be completed May 31, 1969.
The economics of refuse disposal are reasons enough for compacting.
However, with stricter air pollution laws which are in some cities
calling for the shut-down of apartment building incinerators, on-site
compacting is becoming a necessity. Compacting is a space and time
saver. Space, whether on-site, in collection trucks or at landfill
sites, is at a premium. In addition, the compacting in collection trucks
enables collection crews to collect three to four times as much refuse
as without compactors, allowing a substantial saving in labor costs.
-15-
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SECTION IV
REFERENCES
1. American Society of Civil Engineers, CivijL Engineering Manual of
Practice. No. 39, Sanitary Landfill. 1959.
2. Black, R. J. Sanitary Landfills. Proceedings National Conference
on Solid Waste, American Public Works Association, Dec. 1963.
3. Ferguson, F. A. Refuse Disposal, Report No. 298. Stanford Research
Institute, Sept, 1966.
4. Goode, C. S. Utilization of Sanitary Landfill Sites. Proceedings
National Conference on Solid Waste, American Public Works
Association, Dec. 1963.
5. Refuse Removal Journal, Editorial. Oct. 1966.
6. Detroit Metropolitan Area Regional Planning Commission. Refuse
Disposal Plan for the Detroit Region. Jan. 1964.
7. Pennsylvania Economy League and Delaware County Planning Commission.
The Refuse Problem in Delaware County. May 1954.
8. Pollution of Water by Tipped Refuse. Sixty-fourth Annual Conference
of the Institute of Public Cleansing. June 1962.
9. Sheaffer, J. R., B. VonBoehm and J. E. Hackett. Refuse Disposal
Need.s and Practices in Northeastern Illinois with Refuse Disposal
Policies for Northeastern Illinois. Technical Report No. 3,
Northeastern Illinois Metropolitan Planning Commission, June 1963,
10. Black, R. J. and A. M. Barnes. Effect of Earth Cover on Fly Emergence
from Sanitary Landfills. Public Works, Volume 89, p. 91-94,
Feb. 1958.
11. Koenig, L. Unpublished Data. Louis Koenig Research, San Antonio,
Texas, 1967.
12. Haug, L. When Does Transfer Pay Off? Refuse Removal Journal.
Aug. 1966.
13. Black & Veatch Consulting Engineers. Refuse Disposal for Milwaukee
County, Wisconsin. Project No. 4069, July 1965.
14. Refuse Collection and Disposal An Annotated Bibliography 1962-1963.
Public Health Bibliography Series No. 4, Supplement F.
15. Refuse Collection and Disposal An Annotated Bibliography 1960-1961.
Public Health Bibliography Series No. 4, Supplement E.
-16-
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16. Municipal Refuse Disposal. Book prepared by American Public Works
Administration, Public Administration Service, Second Edition,
Library of Congress, No. 66-25574.
17- Black, R. J. and L. B. Near. California Vector Views. Vol. 6, No. 9,
Nov. 1959.
18. Govan, F. A. High Rise Disposal Problem. Refuse Removal Journal.
March 1967.
-17-
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PART 2
COMPOSTING
Prepared by
Edward D. Kane
Manager, Marketing Development
Utility Division
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. SUMMARY 1
II. INTRODUCTION 2
III. CONCLUSIONS 4
IV. RECOMMENDATIONS FOR FUTURE ACTIVITIES 5
V. BACKGROUND 8
VI. COMPOSTING PROCESSES 11
VII. THE BUSINESS ENVIRONMENT 17
VIII. REFERENCES 25
IX. APPENDICES
A. COMMENTS ON COSTS OF COMPOSTING PLANTS 26
-------
SECTION I
SUMMARY
Composting has not been an effective means for municipal solid waste
reduction and disposal in this country. Despite its very early use as a
soil conditioner and fertilizer in Europe, composting has made little
progress toward an industry of any significance in the United States.
Several reasons for its limited progress are: (1) the low cost and wide
use of chemical fertilizers, (2) the high operating and distribution costs
of compost, (3) the limited number of successful composting operations in
the United States and (4) the reluctance of municipalities to enter commercial
ventures.
At the present time, there is an increasing interest in composting
stimulated by proponents of a natural organic fertilizer method of crop
production, soil biologists, and horticulturalists and equipment manufacturers
or process designers-licensors. This current interest is supported by a
forecast of increasing amounts of municipal waste, the decrease of economic
landfill sites and the belief that composting operations can be operated
profitably.
This report describes the different composting processes, and the business
environment. Recommended future activities in the technical and marketing
areas are also presented.
-1-
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SECTION II
INTRODUCTION
Compost results from aerobic decomposition of municipal refuse. When
organic material is decomposed in the presence of oxygen, the process is
called "aerobic". Under proper conditions, municipal refuse will yield
a compost in the form of a granulated material resembling coarse coffee
grounds. Certain materials such as tin cans, glass, and plastic materials
will not convert to compost and must be either salvaged or disposed in a
landfill site.
Composting is a logical consideration for solid waste reduction because
it converts municipal refuse into a useful soil conditioner and because
it can be used to treat not only solid refuse but sewage sludge as well.
The general principles of composting as related to treatment of town
wastes are shown in Figure 1.
Although composting has had some success in Europe, its success in the
United States has been extremely limited. This study was conducted to
determine the reasons for its limited success and to make recommendations
for future activities. Data for the study was obtained by a review of the
literature, a survey of equipment suppliers, and selected interviews with
knowledgeable persons in the composting field.
-2-
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GENERAL PRINCIPLES OF COMPOSTING AS RELATED TO TREATMENT OF TOWN WASTES.
Reference 1
Large Articles -
- Bottles and Jars
- Solvagable Materials
Ferrous Metals
^
^
Rubbish
TO DEALER OR DUMP
TO DEALER
TO DEALER
TO DUMP
MANUAL
REMOVAL
REFUSE
RECEIVING
HOPPER
TO DEALER'S DEPOT
REFUSE SORTING PLANT
APPLICATION OF COMPOSTING TO
TREATMENT OF TOWN WASTES
SEWAGE TREATMENT PLANT
Screenings-
TO DEALER'S DEPOT
DIRECT SALE IN BULK
SHREDDING
k.
W
SLU
TA
i
DGE fc DIGESTION fc SLUDGE
NK ^ TANK ^ DRYER
k
SEWAGE
Effluent
To River or Sea
Figure 1
-3-
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SECTION III
CONCLUSIONS
A. Current demonstration projects, sponsored by Government and private
industry, will determine cost and performance levels of municipal
composting plants and compost usage. The outcome of these programs can
influence the future course of composting in the United States.
B. The success of composting plant ventures must depend on acceptance of
compost as a necessary soil conditioner. It should be noted that the
whole institutionalized effort of agricultural research has been based
on the concept that commercial fertilizers are adequate; and the
productivity of land so fertilized has demonstrated the correctness of
their practice.
C. The economics of composting must be evaluated by each city and consideration
should be given to:
1. The compost supply, the amount of the demand, and its location.
2. The availability of land for composting, i.e. open windrows versus
enclosed digesters.
3. The alternatives available to composting will determine the "dumping
fee" that the city will pay to the composting plant operator to
handle its refuse.
4. Storage space availability for inventory accumulation because of the
seasonal nature of the demand.
-A-
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SECTION IV
RECOMMENDATIONS FOR FUTURE ACTIVITIES
A. MARKETING
1. NEW VIEW OF COMPOSTING
A new view of composting, divorced from the present view that it
must be a commercial venture, should be developed. One possibility
is to use compost in routine landfill operations.
2. PRODUCT SPECIFICATIONS
Determine those qualities and properties that relate compost
benefits to agriculture, horticulture and silviculture.
3. STATE AGRICULTURAL SOIL TEST STATION ASSISTANCE
Agricultural laboratories are in a position to increase user demand
by incorporating compost recommendations in their soil testing
service. However, the whole institutionalized effort of agricultural
research and extension has been based on the concept that commercial
fertilizers are adequate, and the productivity of land so fertilized
has convinced the agriculturist of the correctness of their practice.
4. EDUCATION PROGRAM
A planned educational program is necessary to inform the potential
consumer of the benefits to be derived from the utilization of
compost. The core material for such a program is the subject of
other recommended marketing and technical studies listed in this
section.
5. CREATION OF INDUSTRIAL WASTE UTILIZATION GROUPS
The establishment of such groups to foster industrial waste com-
posting could reduce the burden on municipal refuse disposal systems
and benefit the municipality directly. Such organizations could
also assist in the educational task faced by the composters to
develop a consumer acceptance of compost.
6. INVESTIGATE POSSIBILITY OF BALANCING COMPOST PRODUCTION CAPABILITY
AND POTENTIAL CONSUMPTION
A study should be established to determine the relationship between
compost production potential and soil accommodation or market
saturation. Can such a situation exist, and if so, when? Can such
a situation be prevented in the near term by selective municipal
compost plant construction authorization or regulation? The leverage
of Federal Subsidy should be included in this study for its impact
and effectiveness.
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7. REVIEW OF STATE REGULATIONS AND CLASSIFICATION OF COMPOST
Existing regulations of fertilizer packaging information imposed
by all fifty states require a guaranteed minimum analysis of all
ingredients in fertilizer. As long as compost is to be marketed at
a price premium over non-nutritive soil conditioners like humus or
peat, it must rely on its primary and trace nutrient content.
Being a raw material derived product, its ingredient composition
will vary. A study to determine the basis for the state regulations
and their applicability to compost or a new legal description of
compost would ease the marketing problem facing the composter in
both intrastate and interstate distribution.
8. A STUDY OF MUNICIPALITY PARTICIPATION IN PROFITABLE ENTERPRISES
A question arises when considering the extent and nature of a
municipality participating in a profit making venture. There are
few guidelines for the city administration to follow in this regard
and a study of precedents or reasonable positions would be of value
to assist in their deliberations.
B. TECHNICAL
1. UTILIZATION - EVALUATION METHODS
Establish methods of analysis and evaluation of raw refuse material
samples (and sludge blends) to assess final product compost qualities
for an intended regional market that can be economically served.
2. COMPOST STANDARDS
Prepare national standards of grade and "potency potential" for
categories of compost. Set quantitative ranges for structure,
fertilizing value, trace elements, micro-organism determinations,
etc. Such a standard could also be used as a blending objective
by the municipal compost operator.
3. TECHNICAL COORDINATION
The appropriate Federal fertilizer agencies should seek to actively
participate in, monitor, or seek to assist in planning the programs
of the International Research Group on Refuse Disposal as they
relate to European Municipal compost practices of production,
product utilization and distribution.
4. EQUIPMENT DEVELOPMENT FOR COMPOST SOIL
In an effort to penetrate and realize the commercial compost market
potential, specially designed equipment can be produced that will
facilitate farm soil additions. The spring season soil imposes
restrictions on conventionally available fertilizer spreaders
designed for the summer growing season for fertilizers.
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5. PROPER SOIL BALANCE TO COMPENSATE FOR STEADY CHEMICAL FERTILIZER
AND PESTICIDE (BACTERICIDAL") CROP DOSAGE
To shed light and provide answers for the proponents of natural
fertilizers who claim that the soil is rapidly being denuded of its
basic structure, trace elements, and micro-organisms content by
the present level of dosages of chemicals as fertilizers and
insecticides, herbicides, defoliators, etc., studies should be
conducted to assess the level and rate of this depletion, and the
potential capability of compost to arrest and correct such a
condition if, in fact, it does exist.
6. NON-COMPOSTABLE. NON-SALVAGE SOLIDS DISPOSAL
Effective disposal methods must be evaluated for the composter of
municipal refuse for non-compostable, non-salvage solids. Such
items as aluminum cans, non-magnetic metallic items, rubber tires,
mattresses, plastic materials, glass bottles, and wood wastes, etc.,
must be disposed of in a pollution-free sanitary method that does
not burden the plant operating costs disproportionately.
7. NON-COMPOSTABLE SOLIDS REMOVAL
Materials handling methods are required that will process the incoming
raw refuse material and separate the non-compostable solids for
either salvage sales (when possible) or disposal. The labor cost
involved in sorting this material creates a major cost differential
between natural organic composting and municipal refuse composting
operations.
-7-
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SECTION V
BACKGROUND
Compost is produced as a result of natural fermentation that occurs in moist
cellulosic materials, and is available as a granulated dark brown material
resembling coarse coffee grounds. The finished product, after drying, con-
tains organically bound nitrogen, a large portion of carbonaceous matter
(humus), micro-organisms, and important micro-nutrients. The compost is
usually dried to 10 percent to 15 percent or less moisture.
The major raw materials today employed in domestic commercial natural
organic fertilizers are cow manure, bedding straw and other animal excrement.
Municipal dried activated sewage sludge is also marketed and can be blended
with compost raw material to enhance the fertilizer value of the product.
Municipal refuse; containing much cellulosic material is successfully
composted today. This new material, however, contains a high ratio of
cellulosics to nitrogenous compounds, and more digestive bacterial cycles
converting carbon to carbon dioxide (gas) are required to reduce carbon
content to the accepted ratio range of 20 to 30: 1 parts, C/N. Blending
with higher nitrogen sewage sludge hastens the process by improving the
ratio and also upgrades the final product.
The relative importance of this category of natural organics (and its
compost) can be judged by Department of Agricultural data ' ^ shown in
Table I.
There are numerous processes in operation both here and abroad that can
produce compost. They vary in scope, complexity, and first cost from the
most primitive form of windrow (long mounds) to those employing enclosed
digesters, quantitatively designed, and on which processes and. equipment
patents are held.
Prior to describing the major processes in use, it will be well to review
the agricultural, horticultural and sylvicultural value of compost.
There are six properties of compost that are of interest and concern:
(1) organic nitrogen content, (2) humus content, (3) micro-organisms present,
(4) micro-nutrients content, (5) presence of incorporated solid extraneous
matter, and (6) the possible variation of the chemical and physical pro-
portions of the various ingredients (attributable.to its raw material).
The organic nitrogen is a water insoluble form of nitrogen. Thus rain,
irrigation or watering will not leach away this portion of the total nitrogen
not immediately taken up by the roots. It will be slowly converted to the
active state by the action of the micro-organisms present. Thus, the 5 percent
to 7 percent nitrogen in an enriched compost is longer lasting and is made
available over a longer period of time.
The humus content improves the soil structure enhancing growth and increasing
water absorption and retention, especially important in clay soils.
-------
TABLE I
Blood, dried
Compost
Castor pumice
Cotton seed m
Manure, dried
Sewage si
Sewage si
Tankage
Other
Nitrogen Materials
Phosphate Materials
Potash Materials
Secondary &
Total
Note:
content in all commercial
fertilizers sold in the
United States3
CONSUMPTION OF COMMERCIAL
FERTILIZERS IN THE UNITED STATES2
(tons)
1960
1 2,186
20,428
:e 7,791
meal 35814
td 312,224
;e, activated 89,580
;e, other 32,778
12,730
9,933
: Material 491,454
:, N-P, N-K, P-K 15,64.9,622
-als 4,544,646
ials 2,339,229
-s 474,325
:ro-Nutrient Materials 1,378,12^9
24,877,415
1960
primary nutrient 31.76%
1965
3,290
54,855
3,252
.8,776
360,402
88,340
43,099
12,098
15,117
589,229
18,558,949
7,695,040
2,535,919
935,980
1*521, 286
31,836,403
1965
36.78%
1966
2,762
36,134
3,498
6,864
357,009
91,996
41,221
10,497
12,495
562,476
19,658,957
8,779,205
2,781,565
1,288,624
1,461,388
34,532,215
1966
37.63%
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The micro-organisms present act as soil revivifiers. They convert chemically
prepared nitrogen found in synthetic fertilizers into an available form for
the plant and in this fashion the nitrogen participates in the nitrogen
cycle.
The micro-nutrients, also called trace elements, serve as the necessary
catalysts (enzyme activators), insuring plant health and growth. The exact
mechanism is not completely understood, but seven chemical elements have
been identified in this category.
These four properties of compost comprise the advantages of compost to the
soil scientists and users. These properties are common to manure and
dried, activated sewage sludges. The detractors of compost, and natural
organics, generally, however, point to two additional properties associated
with compost that is prepared from refuse material.
Since the raw material for this discussion is municipal refuse, it will
contain all manner of debris (i.e. rubber tires, tin cans, other ferrous and
non-ferrous materials, glassware and a host of plastic containers and
wrappers). These materials, either all or part, can and do find their way
into the final product, despite varying amounts of care directed to their
removal. The risks engendered by their presence are the jamming or breaking
of spreaders and -tillers, or the ingestion by grazing animals of the broken
glass.
Since the refuse raw material is of varying composition, the percentage
of the basic nutrient elements varies, which, in the case of two of the seven
micro-nutrientss is critical boron and manganese. Variation in primary
nutrient content, nitrogen, phosphorous or potassium, is not critical to the
plants, but raises legal problems concerning minimum guarantees of chemical
composition of the compost, which are required by state registration laws
governing the sale of fertilizers.
Thus, we have compost that can be produced from municipal solid wastes
(whose value can be enhanced with nutrient additions when blended with sewage
solids during its processing), capable of making positive and lasting con-
tributions to plant soil environment. Why is it not a more important
contributor to the fertilizer statistics?
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SECTION VI
COMPOSTING PROCESSES
A. GENERAL TECHNICAL DISCUSSION
Composting in the United States generally employs processes which
involve aerobic decomposition. When organic material is decomposed in
the presence of oxygen, the process is called "aerobic". In aerobic
stabilization, living organisms, which utilize oxygen, feed upon the
organic matter and develop cell protoplasm from the nitrogen, phosphorus,
some of the carbon, and other required nutrients. Much of the carbon
serves as a source of energy for the organisms and is burned up and
respired as carbon dioxide (C02). Since carbon serves both as a source
of energy and as an element in the cell protoplasm, much more carbon
than nitrogen is needed. Generally, about two-thirds of the carbon is
respired as C02, while the other third is combined with nitrogen in the
living cells. If the excess of carbon over nitrogen in organic
materials being decomposed is too great, biological activity diminishes
and several cycles of organisms may be required to burn up most of the
carbon. When some of the organisms die, their stored nitrogen and carbon
become available to other organisms. The utilization of the nitrogen
from the dead cells by other organisms to form new cell material once
more requires the burning of excess carbon to C02- Thus, the amount of
carbon is reduced and the limited amount of nitrogen is recycled.
Finally, when the ratio of available carbon to available nitrogen is
sufficiently low, nitrogen is released as ammonia. Under favorable
conditions, some ammonia may be oxidized to nitrate. Phosphorus, potash,
and various micro-nutrients are also essential for biological growth.
These are normally present in more than adequate amounts in compos table
materials and present no problem hence a discussion of their metabolism
by the biological cells will not be included.
The natural cycle of nitrogen and carbon in aerobic decomposition is the
one which takes place on ground surfaces such as the forest floor, where
droppings from trees and animals are converted into a relatively stable
humus or soil manure. There is no accompanying nuisance when there is
adequate oxygen present for the bacteria. The energy released in the
form of heat in the oxidation of the carbon to C02; a gram-molecule of
glucose dissimilated under aerobic conditions, 484-674 kilogram calories
(kcal) of heat may be released. When the organic material is in a pile
or is otherwise arranged to provide some insulation, the temperature of
the material during fermentation can rise to over 70°C. (158°F.). If
the temperature exceeds 65° to 70°C, however, the bacterial activity is
decreased and stabilization is slowed down. When the temperature
exceeds about 45°C. (113°F.), thermophilic organisms, which grow and
thrive in this range, develop and replace the mesophilic bacteria in
fermenting the material. Only a few groups of thermophiles carry on
any activity above 65°C. (150°F.). Oxidation at thermophilic temperatures
takes place more rapidly than at mesophilic temperatures and, hence, a
shorter time is required for stabilization. The high temperatures
-11-
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destroy pathogenic bacteria and protozoa, hookworm eggs, and weed
seeds in the material that are detrimental to public health and
agriculture.
Complete or perfect aerobic oxidation of organic matter produces no
objectionable odor. When odors are produced, the process is not entirely
aerobic, and the carbon is converted to methane and any sulfur present
to malodorous chemicals. Aerobic decomposition can be accomplished in
silo digesters, pits, bins, stacks, or piles, if adequate oxygen can be
provided. Turning the material at intervals, or other techniques for
adding oxygen are necessary to maintain aerobic conditions.^
To determine how this material can and is being promoted to be made
commercially available, we shall review the current domestic available
processes. Basically, they fall into two major categories open
windrow fermentation, with various modifications and enclosed mechanical
digestor fermentation. Both methods provide and claim, with varying
degrees of success, processes that are aerobic, provide optimum bio-
digestion conditions that maximize yields, with minimum time and plant
area requirements, and to have eliminated burdensome sanitation problems
(i.e. pathogen destruction, odor-free, vermin-free and insect-free
processing).
B. OPEN WINDROW. PILES OR VENTILATED CELLS METHODS
1. WINDROW
The windrow process is conducted in open air and relies on natural
ventilation with periodic turning to insure aerobic conditions.
Only one plant of this type is operating in the United States. It
is located at Wilmington, Ohio, was built in 1963, and processes
twenty tons of refuse per day. "A minimum of sorting is provided
and two hammermill grinders are used in series. The ground refuse
is composted in windrows where it is turned weekly by means of a
front-end loader until the material is converted to compost.
Difficulties have been experienced in selling the finished compost."-'
2. VENTILATED CELL
Ventilated cell composting employs a multi-story building with a
vertical arrangement of progressive cells. Mixing and aeration occur
when the material drops from cell to cell.^ Several different
methods have been tried based on the ventilated cell process. In
the United States the Naturizer Process, the Riker Process, the
Frazer-Ericson Process, and the Fairfield-Hardy Process have all
been tried with little success.
a. THE NATURIZER-PROCESS
The first plant using the Naturizer Process was built in
Norman, Oklahoma in 1959. It was closed in 1964 except for
experimental purposes. "Two unique features of the plant were
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a specially designed swing hammermill and the Naturizer Composter.
The digester system provided six day retention in two, three
story buildings with a movable floor in each story. Considerable
time and effort were expended to build up a market for the
product, with sales activity extending as far away as Dallas,
Texas." The second plant using this process was located^in
San Fernando, California and began continuous operation in
July of 1963. It was shut down in October of 1964. "The plant
had a capacity of 70 tons of refuse per day, but operated at
only about 40 tons per day. It was an improved version of the
process developed at the Norman, Oklahoma plant. Appreciable
salvage operations were performed. It was necessary to provide
an afterburner on top of the composting unit to comply with
Los Angeles County Air Pollution Control District requirements
to insure that no odors would be discharged. Compost was sold
in bags and in bulk. A unique development for the use of compost
was called 'Sta-Soil' which was a water suspension of compost,
chemical fertilizer, grass seed and shrubs. It was sprayed
over denuded slopes, or cuts and fills, to provide a blanket
against soil erosion and a 'soil' in which grass and shrubs would
quickly take root."^ The latest plant using this process is
located in St. Petersburg, Florida. The International Disposal
Corporation operators of the plant have a twenty year contract
with the city of St. Petersburg. This contract calls for the
disposal of 100 tons of refuse per day, six days a week, at a
cost of $3.24 per ton to the city.
The digester is a five story building with conveyors running
the length of each floor. In operation the conveyors will
travel their length (150 to 165 feet) in twelve hours and remain
stationary for twelve hours. After passing through the digester
and final screening, the material is dumped in the finishing
yard where it is left for two weeks. The material is marketed
under the name of "Cura" and finds favorable acceptance for use
in citrus groves, golf courses, commercial nurseries, and with
industrial landscape architects. The St. Petersburg plant cost
$1.5 million.
b. THE RIKER PROCESS
A plant using this process was built in Williamston, Michigan in
1955. It was closed in 1962 when the only customer it had
stopped purchasing the compost. "This four tons of refuse per
day plant treated garbage, vacuum-filtered raw sewage sludge
and corn cobs. Ground garbage and corn cobs, mixed with sludge
cake were composted for twenty-one days in two, four compartment
vertical composters." ^
c. THE FRAZER-ERICSON PROCESS
A plant operating under this process was built in Springfield
Massachusetts in 1954. It was closed in 1962 when the city failed
to renew the contract. The plant had a capacity of twenty tons
-------
of garbage a day. The garbage, being too wet to compost
aerobically, was held for about two days to dewater. This
frequently created fly, rat and odor problems.
d. THE FAIRFIELD-HARDY PROCESS
A plant located in Altoona, Pennsylvania began operations in
1950 using the windrow method, but was converted to the
Fairfield-Hardy Process type operation in 1963. "Refuse is
ground in a wet pulper, followed by dewatering presses (Figure 2)
before it is fed into the Fairfield-Hardy Digester for a five
day cycle."^ "Stirring is provided by augers suspended from a
rotating bridge in a circular tank. Air is provided by means
of a blower and air pipes embedded in the floor of the tank.
Normal operating temperatures are about 140 to 160°F. The
plant has a capacity of 45 tons per day but normally operates
at about 18 to 23 tons per day. Successful experiments have
been run in which digested sewage sludge was added to the ground
refuse."4 The city of Altoona pays the operators of the plant
$4.63 per ton for processing their garbage. From the 7,000
tons of garbage processed a year, 3,150 tons of saleable compost
are obtained. A total of 1,300 tons of coarse compost sells for
$5 per ton and 1,850 tons of the dried and pelletized compost
sells for $20 per ton if it has a 5 percent to 17 percent
moisture content. A plant of this type which could process
100 tons per day would cost approximately $900,000, including
land. A prototype plant built in Largo, Florida originally
utilized the Fairfield-Hardy Process, but was rebuilt in 1963
by the National Composters Company who installed a digester of
their own design. "This plant has a capacity of 50 tons per
day. Operating five days a week, it treates 40 to 50 tons per
day of mixed refuse to which is added 1,000 to 1,500 gallons per
day of essentially raw sewage sludge."4 The essential difference
in the digester is that the material is turned, not by the augers,
but by a rail-mounted bucket elevator moving in either direction.
The product sells for $16 per ton. Another plant has been
built in Houston, Texas, by the builders of the Largo, Florida
plant. This $1.75 million plant has been designed to process
300 tons of garbage per day, six days per week. The city of
Houston pays $4.51 a ton for this service. The end product of
the operation is called "Metroganic 100". It is being sold to
rice farmers, citrus growers and others engaged in agriculture,
particularly those in the Rio Grande Valley. To date, the
success of the operation has not been determined.
C. CONTINUOUS MECHANICAL COMPOSTING
This process involves continuous mixing with gradual particle size
reduction and positive aeration.^ There are several systems that use
continuous mechanical composting the Dano Method, however, is the only
one used in the United States.
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SCHEMATIC OF COMPOSTING PLANT UTILIZING FAIRFIELD-HARDY DIGESTOR.
JO) SLUDGE FROM SEWAGE TREATMENT
PLANT TO DIGESTER
9) GARBAGE
TO DIGESTER
\ (13) PELLETIZER
11) FAIRFIELD-HARDY
DIGESTER
12) STORAGE
& CURING
4) WET
PULPER
5) COMPOST TO TRUCKS OR BAGS
8) DEWATERER
2} SORTING & SALVAGE
1) REFUSE RECEIVING HOPPER
7; RESIDUE
TO LANDFILL
6) GRINDER
OR BURNER
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1. THE DANO BIOSTABILIZER SYSTEM
The Biostabilizer is a large drum, 9 to 12 feet in diameter and
60 to 100 feet long. It is designed to effect continual mixing,
aeration, grinding and decomposition in one unit. Refuse material
first passes through sorting and magnetic separation before being
charged into one end of the slowly revolving unit (,25 to .8 rpm).
Water and sludge are also added at the inlet. Slow grinding is
accomplished by the tumbling shearing action of the Biostabilizer
which, with decomposition, processes the refuse so it will pass out
through coarse perforations (4 inch diameter) at the outlet end.
This operation is followed by a second magnetic separation, vibrating
screen and a ballistic or gravity separator before the partially
decomposed refuse is arranged in windrows for curing. It is said
that five to seven days' composting in the Biostabilizer unit is
equivalent to three to four weeks of windrow composting with several
turnings, although material coming out of the Biostabilizer is not
sufficiently decomposed to be stable and will reheat again when
moist. For this reason, windrow composting is used in the finishing
stage.5 The first plant to use the Dano System in the United States
was built in Sacramento County in 1957. It had a capacity of about
40 tons per day. It was closed in 1963 for lack of a market for its
product. The second plant using this system was built in Phoenix,
Arizona in 1962, originally scheduled to process 300 tons per day
with two Dano Biostabilizers using a three day cycle. However, two
additional units were added and actual capacity was still only 175
tons per day. The plant was closed in 1965 because it could not
compete with the cost of landfill operations.
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SECTION VII
THE BUSINESS ENVIRONMENT
A. GENERAL
To properly understand the marketing and financial problems, let us
consider the current business environment in which compost finds itself.
There has been a constant increase in the sales of chemical fertilizer
with steadily increasing concentrations of prime nutrients (see Table I).
This reflects the increasing pressure for greater yields per acre of
commercial crops by the grower. Insecticides follow the same trend,
and are produced by the same manufacturers. Approximately 2 percent
of the tonnage of the total commercial fertilizer marketed is composed
of natural organics. Compost, included in this category, approximates
0.1 percent of the total fertilizer consumption. To date, therefore,
it does not represent a significant factor to be reckoned with by the
fertilizer industry. Of more concern to the municipal composter are
the other suppliers in the natural organic category of Table I who
will be competing for the same portion of the market.
The recent interest in composting is stimulated not by new potential
users clamoring for its availability, but rather by potential suppliers
and equipment manufacturers of composting plants. A critical gap
exists between those ready to supply compost and those who are ready
to use the material. This gap constitutes the marketing problem facing
the potential municipal refuse composters.
The attractiveness of a process capable of converting a waste that must
be ultimately and completely destroyed into a saleable commodity (at a
profit) has strong appeal to the entrepreneur. Its appeal has also not
been lost to the municipalities by which they hope to ease their tight
fiscal situations.
A municipality has a number of approaches to consider. The municipality
can: (1) own and operate the plant and market the product (2) own
and operate the plant and contract out the product marketing, (3) Con-
*nHCm°r US ^USe t0 ^ C°mP°sted and ^rketed by a private operator
and (4) as in (3), except it can additionally contract for the collection,
It accepts the greatest financial risk when it assumes the total
scope - owns, operates and markets; it accepts the least risk when it
contracts for the collection, operating and marketing. Irrespective of
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this consideration, the municipality cannot escape its prime respon-
sibility for the safe and complete elimination of its solids waste.
It should, therefore, view any arrangement with this long term major
objective clearly in mind.
There are cases of a city owning the waste material processing plant
and marketing the product. The products, however, are dried or processed
sewage sludges. The raw materials are brought to the plants by under-
ground pipe and the collection, sorting and preliminary operations of
composting are not necessary. The drying (and packaging) operations
are added to an otherwise normal sewage treating plant. The marketing
of the material is handled by the community. Milwaukee (Milorganite),
Houston (Hu-Actnite), Chicago (Chicagrow), Pasadena (Nitroganic),
Schenectady (Orgro) are a few of the trade named products successfully
marketed.
The operating costs, in order to produce a marketable commodity, are
but incrementally increased over and above the cost of normal processing
of sewage wastes. The material is marketed at a low enough price, on
a dollar per unit of active ingredient basis, to be attractive to
users, and the return on the incremental portion of the cost of pro-
duction is attractive to the city.
Thus, there exists a precedent for a city to operate and own a product
manufacturing and marketing capability. The major difference between
sludge and compost lies in the incremental cost of producing a dried or
activated sludge and the equipment cost to compost (or incinerating)
that requires a major capital investment in a new facility.
A city can produce the material and at a yearly auction, or through
sealed bid procedure, contract out the annual plant capacity. This
approach also has been used with sludge.
In the third and fourth alternatives mentioned above, the city pays the
operator a fee for each ton of its refuse delivered to the contractor's
compost facility. The contract is usually of twenty or more years
duration, to satisfy the private operator's need of a continuing source
of supply for his plant. The fee agreed upon by the city (dumping fee)
will be less than the cost of any practical alternative for its waste
disposal, and must be enough to contribute substantially to the
operating revenues. He theoretically can thus market the compost at
prices that are competitive and profitable and that are an economically
attractive source of soil conditioner-fertilizer to the grower-user.
The city "dumping fee" and the compost sales income are the only
reasonable revenue sources. A salvage income is sometimes quoted in
connection with the "sorting operation"; however it does not appear to
be good business practice to rely on this very flexible, non-stable
income when forecasting future profitability.
The physical compost plant can be designed and erected by an operator's
organization, by a turn-key plant builder under contract to the operator,
or by an architect-engineer who designs, purchases and manager con-
struction of the plant.
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B. COSTS
Estimates of plant costs obtained from the literature are given in
Table II. A detailed cost estimate for three different plant capacities
which was provided by Fairfield Engineering Company is presented in
Table III. In addition to plant costs, this table gives an idea of the
"dumping fee" which is the charge to the city for every ton of refuse
handled. "Dumping fees" are presented for two different situations:
(1) a private owner^operator and (2) a private operator.
Some additional comments on qualitative costs of composting plants are
given in Appendix A.
C. PROBLEMS
Some problem areas which have constrained the growth of composting are
listed below.
1. INSUFFICIENT OR LACK OF OPERATING PROFIT (DUMPING FEE)
There are instances of operating plants closing for lack of profit.
The total income of any plant is the sum of compost, salvage and
dumping fee revenues. The operating plant cash expenses include
plant labor, utilities, the cost of initial investment capital,
supplies and chemicals, administrative, insurance, taxes and
advertising and sales promotion. The non-cash expenses include
depreciation of equipment, and in some cases, the amortization of
process development.
All the expense and cost items are standard, industrial type plant
operating expenses, and if we assume a properly sized plant has
been constructed, and a uniform delivery of municipal refuse is
maintained, these costs remain essentially constant. Further, the
sales price of salvage items must not be included in income pro-
jections as it is subject to wide fluctuations in price value with
time and by location. The sales price of compost is variable, but
a market value will be established that should be essentially
constant for a given moisture content, primary nutrient content,
package size, grind size and uniformity.
The last item of plant income, and subject to negotiation, is the
city dumping fee. The upper limit is usually fixed by the cost of
the next reasonable, practical method of solids disposal. This fee
is set for a long term, and is critical to the eventual success of
compost venture. If the city accepts an unrealistically low offer
by an optimistic composter, it may ultimately end up with a
non-operating plant and no place for its waste.
2. LACK OF PRODUCT COMPOST SALES (PRICING)
When the operator above seeks to remedy his profit picture, he can
only raise his sales price. The scope of the plant is fixed as are
the sanitary and other standards and regulations that control his
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TABLE II
COSTS AND LISTING OF DOMESTIC MUNICIPAL SOLIDS REFUSE COMPOSTING PLANTS
IN OPERATION, TOPER CONSTRUCTION OR AUTHORIZED. AS OF JUNE 1967
o
i
Location
Altoona, Pennsylvania
Boulder, Colorado
Gainesville, Florida
Houston, Texas
Houston, Texas
Johnson City, Tennessee
Largo, Florida
Mobile, Alabama
St. Petersburg, Florida
Capacity
45 T/Day (1)
100 T/Day (Est.)
150 T/Day
300 T/Day
300 T/Day
60 T/Day
50 T/Day
300 T/Day
105 T/Day
(Over 45 T/Day Capacity)
Type
Operator
FAM
Rich-Land
Metro
Metro
United Compost
TVA-PHS-City
Metro
City of Mobile
International
Disposal Corp.
Approximate
Plant Cost
(OOP's Omitted)
Enclosed Digestor
Open Windrow $ 250 (Est.)
Enclosed Digestor $1,100
Enclosed Digestor $1,750
Enclosed Digestor
Open Windrow $ 750
Enclosed Digestor -
Open Windrow $1,100
Enclosed Digestor $1,500
Status
Operating
Operating
In Construction
Operating
Not Operating
In Construction
Used for
Development Work
Operating
Operating
(1) Tons per 24 hour day of refuse.
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TABLE III
ESTIMATED COSTS FOR 100, 200 & 300 TON PER DAY ENCLOSED DIGESTOR PLANTS
FURNISHED BY FAIRFIELD ENGINEERING COMPANY, MARION, OHIO
Fairfield-Hardy Disposal Plant, March 28, 1967
Daily Annual
Capacity Tonnage
of Plant 5 1/2 Day/Week
100 Tons 28,600
of Refuse
200 Tons 57,200
of Refuse
300 Tons 85,800
of Refuse
Annual
Amortization Annual
Construction & Financing Operating
Cost Cost Cost (1)
$1,370,000 $129,000 $125,000
$2,000,000 $189,000 $196,000
$2,500,000 $234,000 $248,000
Dumping Fee to
Operator Who Owns
and Operates Plant
$6.50 per ton of
Refuse
$5 . 50 per ton of
Refuse
$4.50 per ton of
Refuse
Dumping Fee to
Operate Plant
Only
$4.37 per ton
Refuse
$3.43 per ton
Refuse
$2.90 per ton
Refuse
of
of
of
(1) These plant operating costs cover refuse conversion costs only. To market product compost, the annual
operating cost would be increased, but these costs can be offset by sales revenues.
Assumptions:
1. One pound of compost for every three pounds of refuse.
2. 7.3 percent return on investment.
3. Land not included.
4. Real estate and personal property tax not included.
5. Amortization and Financing Costs: 20 years - buildings and stationary equipment; 5 years - mobile equipment;
interest at 6 percent.
-------
method of operation. His product must bear a price value relation-
ship to other competitive natural organics or humus-nutrient blends.
When this is arbitrarily altered, he is no longer competitive nor is
he providing a product of economic benefit. Accordingly, he will
lose whatever market he has succeeded in developing.
3. LACK OF PRODUCT COMPOST SALES (USER DEMAND)
Despite the potential benefits of compost additions to soil, the
readily apparent improvement to crop yield is adequately met by
chemical fertilizers. Compost-soil additions are long term in their
effects. Such protracted benefits are not met with enthusiasm by the
large commercial operators in but a few isolated exceptions. In
many cases, organic matter additions are incorporated into the soil
by plowing under, either stalks remaining after harvest, or by
"green manure". Many farms prepare their own compost piles and thus
derive all the benefits mentioned earlier without placing any demands
on the commercial compost or natural organics markets. Abundant
supplies of manures and other /natural organics are readily available
in all agricultural markets (see Table I).
4. LACK. _OF PRODUCT COMPOST SALES (TRANSPORTATION COSTS)
The municipality and its composter have no control over location of
the market. The cost of shipping urban produced compost to either
the rural consumer grower or the regional commercial fertilizer
blending plant is a marketing distribution constraint.
The figures tabulated in Table IV from the Uniform Freight
Calssification of September 20, 1966 are the costs per ton for two
slightly different commodity freight classes, for various selected
mileages.'
TABLE IV
FREIGHT COST - DOLLARS PER TON7
Class, 20 Class 22-1/2
Miles (humus, sewage sludge, etc.) (peat moss)
100 $ 6.40 $ 7.20
200 8.40 9.40
300 10.00 11.20
400 11.60 13.00
500 13.00 14.60
600 14.20 16.00
800 17.00 19.20
1,000 19.20 21.60
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It should be noted that between 400 to 500 miles, in category 20,
the shipping cost equals the product cost. This distance has also
been mentioned as a limit to the economic distance compost can be
shipped.
The natural organics or peat moss supplier, with a much lowermost
of production, can ship at least once again as far as the municipal
refuse composter for equivalent freight costs because their pro-
duction cost is but a fraction of the refuse composter, (i.e. the
former from $1 to $5 per ton, whereas the net cost of compost is
$10 to $12 per ton). He requires no elegant physical plant in an
urban surrounding; he requires no sorting labor, and his land costs
are much less, enabling him to windrow compost.
5. LACK OF SALES (USER DEMAND - EDUCATION)
This market could be expanded but would require the indirect assistance
of the state agricultural services. These organizations will
analyze soil for any interested citizen or organization, but the
standard analyses are presented in terms of chemicals required.
This can be related directly to pounds of chemical fertilizer. No
data is available from these routine analyses concerning the
qualitative aspects of soil beneficiation to be expected from the
incorporation of compost. This further suggests a consumer education
enlightenment program to make the benefits possible from compost
additions more widely recognized and appreciated.
6. OPERATING PROBLEMS (_SANITARY)
Certain of the forced shut downs have been attributed to malfunctioning
processes that have created problems of odor, vermin infestation,
or insect growth. Such processing problems have contributed much
to the lack of new plant construction despite constant technical
improvements.
7. POLITICAL EXPEDIENCY
Since many composting plants have been forced to shut down for one
reason or another, municipal authorities are cast as innovators if
they recommend composting plants for their communities. Many
plants must be in successful operation in order for composting to
be a "safe" recommendation.
8. SOCIAL UNATTRACTIVENESS
As the cost of landfill operations and incinerator costs increase
the operating cost advantages of a municipal compost plant become'
apparent a fixed location for the delivery of the refuse. For
any given community there is a cost benefit of size scale-up that
can help to reduce the per pound production costs of the compost.
These two cost benefits (delivery and scale-up) combine to suggest
that the largest reasonable size plant be located as close to the
population center as possible. For large (over 500,000) populated
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cities, this same reasoning applies to multiple centrally located
plants. This places the compost plant(s) within the city proper
and the locally affected neighborhood citizen reaction can be
expected to argue against any such nearby location, despite any
and all of the operator arguments and guarantees.
These considerations are the major constraints on the compost industry,
Obviously, they do not all apply to every situation, and hence some
headway has been made, attested to by the fact that an infant compost
industry does exist. Each of the negative points can be answered when
raised one by one. In the face of them altogether, however, the task
appears formidable.
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SECTION VIII
REFERENCES
1. Davies, A. G. Municipal Composting. London, England. 1962.
2. U. S. Department of Agriculture, Statistical Reporting Service, Crop
Reporting Board. Consumption of Commercial Fertilizers in the
United States. Washington, D. C. 1966, 1965 and 1960.
3. U. S. Department of Agriculture, Statistical Reporting Service, Crop
Reporting Board. Consumption of Commercial Fertilizers and Primary
Plant Nutrients in the United States. Washington, D. C. June 1966.
4. Waste Engineering and Research, Inc. Report on Solid Waste Disposal.
Atlanta, Georgia. Dec. 1965.
5. Wiley, J. J. and 0. W. Kochtitzky. Composting Development in the
United States. Compost Science. Summer 1965.
6. Refuse Removal Journal. Composting - Is it Economically Sound. July 1966
7. Hackler, J. D. Uniform Freight Classification of September 20, 1966.
Chicago, Illinois.
8. Compost Science. Marketing of Large Amounts of Compost. Spring 1960.
9. Gotaas, H. B. Composting. World Health Organization. 1956.
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'MS
SECTION IX
APPENDIX A
COMMENTS ON COSTS OF COMPOSTING PLANTS
The following comments by Gotaas^ serve to describe the general problei
involved in developing cost estimates of composting plants.
"It is impossible to develop cost estimates that would be significant for
different installations, locations, or currencies. Perhaps the best economic
analysis can be made by comparing cost estimates and data for composting
with the costs of incineration in a given locality, or by comparing the cost
of production of the compost with the selling value of fertilizers of similar
quality to composted municipal wastes, for example, animal manure. The
value of compost as a fertilizer and soil builder is not established in many
parts of the world.
In the Netherlands, the composting of organic municipal wastes has been
practiced in several places for many years and has proved cheaper than
incineration of the wastes and, in areas where there is a good nearby market
for the compost, as cheap as sanitary landfill. Disposal of refuse by
composting and selling the product as a fertilizer has been found to be
economic in Denmark, Germany, Italy, India, the Union of South Africa, and
several other parts of the world. In California, the Compost Corporation of
America, in analyses used as the basis for planning a plant, found that
compost of a nutrient quality as good as that of stable manure and free
from weed seed, could be profitably produced to sell for less than the normal
price of stable manure. Seabrook, after experience of pilot plant composting
at Tacoma, Washington, has estimated that the Tacoma refuse can be composted
at a profit to the city, without including the savings affected by eliminating
the present method of disposal by sanitary landfill and is proceeding on
this basis with the development of a full scale composting plant.
At the five ton per day Bio-stabilizer composting plant at Ruschlikon,
Switzerland, the returns from the sale of compost and salvage amount to
50 percent of the cost of composting, thereby reducing the cost of refuse
disposal. It is believed that the costs per ton would be lowered considerably
in a larger plant.
It is estimated that in the United States the cost for converting refuse
delivered to the site into a compost, using the windrow method, will be as
low as 30 to 60 percent of the cost of incineration for plants with a
capacity of over 100 tons per day. Provided that delivery to the compost
site did not require a much more expensive haul than delivery to the inciner-
ator site, then, even if the compost were given to those who would haul it
away, the operation would be cheaper than incineration. The major part of
the difference in cost between composting by the windrow method and
incineration lies in the fixed cost of the plant. Cost estimates for the
windrow method plant as compared to the incineration plant, on a per ton
per day basis and a one shift operation, indicate that the compost plant will
cost from 20 percent to 25 percent less than an incinerator installation for
capacities of over 100 tons per day-
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Estimates for the costs of composting with the Dano Bio-stabilizer plant
with a capacity of 25 or 50 tons per day are about the same as for incineration.
The initial cost per ton of refuse is considerably higher for the small
Bio-stabilizer plants than for the larger windrow method plants. However,
the Bio-stabilizer, like the incinerator, can be located in the city to
reduce hauling costs.
The major uncertainty regarding costs of disposal by composting appears
to be whether or not the material will be accepted by farmers and gardeners
and can be readily sold or disposed of."
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PART 3
APARTMENT HOUSE INCINERATORS
Prepared by
Harold Maisjsner
Consulijat
Formerly Assistant Director of Engineering
New York City Department of Air Pollution Control
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. SUMMARY l
II. RECOMMENDATIONS FOR FUTURE ACTIVITIES 2
III. NUMBER AND SIZE RANGE OF APARTMENT HOUSE INCINERATORS 3
IV. WASTE DISPOSAL METHOD
A. INCINERATION 4
B. COMPACTION 4
C. SHREDDERS, GRINDERS AND PULPING 4
D. GARBAGE GRINDERS 5
E. BALING NEWSPAPERS 5
F. BULK DENSITIES 5
V. INCINERATION REQUIREMENTS
A. FLUE-FED INCINERATORS 6
B. CHUTE-FED DESIGN 6
C. UPGRADING EXISTING INCINERATORS 6
VI. PERFORMANCE STANDARDS 10
VII. CONSTRUCTION SPECIFICATIONS H
VIII. REFERENCES 12
-------
SECTION I
SUMMARY
As part of an overview of solid waste disposal in urban areas, a brief
investigation was conducted on disposal methods of solid waste in apart-
ment houses in New York City. This report is based primarily on the
experience of the writer, who during the last few years was Assistant
Director of Engineering of the New York City Department of Air Pollution
Control.
New York City has approximately 12,610 incinerators installed in apartment
houses having a total population of 2,700,000. The two principal types of
incinerators are (1) flue-fed incinerators in which refuse is charged through
hopper doors on each floor into a refractory flue, the bottom of which
opens directly into the top of the furnace or combustion chamber, and
(2) chut-fed designs where refuse is charged through hopper doors on each
floor and collected in a basement hopper, from which it is transferred
either manually or mechanically to the incinerator furnace.
Methods of upgrading present incinerators are described, together with
suggested research and development programs.
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SECTION II
RECOMMENDATIONS FOR FUTURE ACTIVITIES
A. Develop simplified test procedures for measuring pollutants in stack
gas to replace the tedious and costly methods now required, and
instruments to indicate and record emissions continuously, which is
now possible for smoke, but not for fly ash.
B. Develop means for elimination of the water vapor plume frequently
emitted when wet scrubbers are employed, which may be mistaken for
smoke and which becomes the source of complaints.
C. Develop means for feeding the refuse continuously rather than inter-
mittently to the incinerator, to avoid the peaks and valleys which
seriously interfere with good combustion control.
D. Improve the design of charging hopper doors on each floor, to reduce
air leakage, prevent plugging of the flues with oversize refuse, and
overcome the smoke-outs now experienced.
E. Develop water cooled furnaces to reduce slagging of refractory, permit
higher furnace temperatures, decrease excess air requirements, thus
minimizing fly ash and other undesirable emissions, and which may
incorporate heat exchangers for generation of hot water, etc.
F. Design low cost dust removal equipment such as electrostatic precipitators,
bag filters, or dry type high efficiency cyclone collectors, all of
which would reduce the water consumption and handling problems inherent
in wet type designs.
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SECTION III
NUMBER AND SIZE RANGE OF APARTMENT HOUSE INCINERATORS
New York City has prohibited incinerators in buildings which house less
than 12 families for many years, largely because of improper maintenance
and excessive pollution. Typical incinerators range from 85 pounds per
day capacity to a maximum of 3,400 pounds per day, which would satisfy the
needs for a 2,000 tenant building. The average incinerator design capacity
is about 350 pounds per day. There are some 12,610 incinerators serving
apartment houses, having a total population of 2,700,000. The average
refuse per person per day is about 1.63 pounds. Total refuse incinerated
in these buildings is approximately 800,000 tons per year.
The residue has one-tenth to one-fifteenth of the volume of the original
refuse, with a weight reduction of at least 75 percent. Most of this residue
is in the form of bottles, cans, and ash, with 5 to 15 percent combustible,
largely food products. The following composition of residue has been
reported.
Metal and glass over 1/4 inch 64 percent
Ash from combustible matter 12 percent
Unburned combustible matter 16 percent
Moisture from latter 8 percent
Tests have shown unburned combustible matter can be decreased to under
5 percent, with no measurable moisture, with improved incinerator design.
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SECTION IV
WASTE DISPOSAL METHODS
A. INCINERATION
This method will reduce the volume of the residue to 10 percent or less
of the refuse charged, and the weight to 25 percent or less on the same
basis. There is therefore a major reduction in the handling and storage
requirements at the building, as well as in the pickup and disposal
facilities to the dump area. The residue is sterile and odorless com-
pared with the refuse, so that tenant complaints, and health hazards
from vermin are minimized. Fire danger is also eliminated.
I ncineration at the building will reduce the number of cans of refuse
to be stored from ten or fifteen to one required for the residue.
Tests observed in 1966 reduced sixteen cans of refuse to one can of
o
residue, most of which comprised cans and bottles.
B. COMPACTION
The compaction volume may be reduced to one-half or one-third the
volume of the original refuse, so that storage room requirements are
decreased with no change in weight. There are several systems for this
purpose. In the first, refuse is forced into metal containers by
mechanical pushers, stored until dumped into the pickup trucks, during
which operation it may regain much of its original volume.
Another compaction system forces the refuse into heavy paper bags,
which are then sealed and deposited in the truck, so that the initial
reduction in bulk is retained. This is satisfactory for landfill
disposal, but experience has shown that the bags must be broken apart
if delivered to a municipal incinerator, to avoid delayed combustion in
the furnace and high unburned combustible loss. In a third system, the
refuse is compressed in portable metal containers, which are picked up
and carried to the disposal facility for unloading, and returned to the
building, at added hauling cost.
In the above compaction systems, there is no reduction in the weight
of the refuse, and a temporary decrease in bulk. The refuse remains in
a putrescible state and is inflammable, which may require fireproofing
the storage room to avoid fire, and cooling to avoid odor and vermin
problems.
C. SHREDDERS, GRINDERS, AND PULPING
By addition of water after maceration, these methods reduce the volume,
but add materially to the preparation cost. The ultimate disposal
problem may be complicated because the finely ground material has been
found to pack, and burn too slowly in an incinerator, especially when
water has been added.
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D. GARBAGE GRINDERS
This method requires separation of the food products in the refuse from
most of the other material. As the former comprises only ten to fifteen
percent of the total refuse, and is the least bulky for storage, the
saving in disposal costs is relatively small. Such equipment is pro-
hibited in New York City, because of the added load on the sewage disposal
system, into which the ground material is discharged.
E. BALING NEWSPAPERS
When there is a market for scrap paper, which may comprise up to
20 percent by weight of the total refuse, the cost of separation and
handling can be justified. Loose collection in cans or bags requires the
greatest storage room space, and handling labor, as well as being most
subject to fires, odor and vermin problems.
F. BULK DENSITIES
Bulk densities of the several materials involved have been measured as
follows, subject to variations in moisture and other factors. Weight
of the refuse as deposited in the incinerator through the usual charging
flue is 4.1 pounds per cubic foot or 111 pounds per cubic yard. Residue
as removed from the incinerator, including some moisture used for
quenching is 15.4 pounds per cubic foot or 416 pounds per cubic yard.
This includes 65 percent to 70 percent metal, mostly cans, and glass
such as bottles and jars.
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SECTION V
INCINERATION REQUIREMENTS
There are two general types of incinerators available; the major difference
being the method of feeding the refuse from the various floors into the
furnace.
A. FLUE-FED INCINERATORS
Flue-fed incinerators are those in which the refuse is charged through
hopper doors on each floor into a refractory flue, the bottom of which
opens directly into the top of the furnace or combustion chamber. In
the single flue design-^ shown in Figure 1, the combustion products flow
upward through the charging flue and are discharged above the roof of
the building, whereas in the double flue type the refuse is charged
down one flue, and the combustion products normally flow upwards in the
parallel flue, both flues being lined with refractory material.
At suitable intervals the hot gas from the auxiliary burner may be
discharged upward through the charging flue to purge or sterilize it of
any odors or vermin that may have accumulated on the walls. For this
reason, both flues must be open at the top for free exit of whatever
combustion products are produced. As an alternate to this hot gas
purging the charging flue may be sterilized by use of suitable spray
nozzles and detergents.
B. CHUTE-FED_DESIGNS
Chute-fed designs are those in which the refuse is charged through hopper
doors on each floor as above, into a metal chute, collecting in a
basement hopper, from which it is transferred either manually or
mechanically to the incinerator furnace (see Figure 2). The combustion
products pass up and out through a refractory flue, above the roof.^
C. UPGRADING EXISTING INCINERATORS
Many of the existing incinerators can be brought up to satisfactory
performance by incorporating the design factors that have been found
beneficial in the new units, without major changes or costs. Because of
the intermittent nature of refuse charging, the incinerator normally
operates for only three to four hours per day. By spreading this burning
period, the load for each burn is reduced, so that even an undersize
furnace can be made to function satisfactorily.^
Many cities have permitted burning only during daylight hours, or when
the day porter was on duty. In New York City for example, the burning
time was 7 A.M. to 5 P.M. One result was that between 5 P.M. and 7 A.M.
the refuse would pile up in the charging flue to the second or third
floor, which causes a serious pollution problem when the porter ignites
the refuse the next morning.
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SINGLE FLUE WITH WASHER OR PRECIPITATOR
ON ROOF
Reference 3
REFERENCE
Low Galvanized Wire Screen
Washer Enclosure
Washer and I.D. Fan
Hopper Door, Locks Optional
5. Charging and Gas Flue
6. Inadequate Grate Area
7. Flat Hearth
8. High Stainless Steel Screen
9. By-Pass Damper with Remote
Control
Gas Inlet to Washer
Steep Hearth
Enlarged Grate Area
Under Fire Air Register
Outside O.F.A. Manifold and Fan
Inside Ditto
Auxiliary Burner
10.
11.
12.
13.
14.
15.
16.
SECTION A-A
SECTION B-B
Figure
-7-
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DIRECT FED INCINERATOR AND CHARGING CHUTE
Reference 3
titrr.&itf]
REFERENCE
1. Safety Cap for Fire Protection
2. Detergent Spray for Purging
3. Sprinkler Head for Fire
Protection
4. Hopper Door
5. Refuse Chute
6. Refuse Hopper
7. Cleanout Door
8. Grating for Drainage
9. Waste Water to Sewage
10. Stainless Steel Screen
11. Roof Slab
12. Gas Flue
13. Draft Control Damper
14. Barometric Damper
15. By-Pass Damper Auto.
Controlled
16. Charging Apron
17. Hearth
18. Grate Area
19. Guillotine Charging Gate
Power Operated
20. O.F.A. Manifold and Fan
21. Washer and I.D. Fan
22. Auxiliary Burner
SECTION A-A
Figure 2
-8-
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The introduction of automatic controls for igniting the refuse in the
furnace and controlling the combustion air, has permitted extending
the burning time, in some cases to 18 hours or more so that the overnight
pile-up is eliminated and four or more burns are accomplished, with
major improvement in the performance. The principal elements included
are listed below.
1. Auxiliary burner in the furnace or primary chamber to ignite the
refuse and maintain desired temperature in conjunction with the
heat from the refuse.
2. Overfire air fan with manifold and nozzles to assure adequate
turbulence and complete burnout of the volatile combustibles.
3. Programming electric clock with 24 hour dial and adjustable contact
pins to permit starting and stopping of the above items at preset
intervals. All controls to be enclosed in tight steel box.
4. Fly ash removal equipment adequate to meet the local ordinances.
The reduction in emissions by the methods described above is approximately
as follows:
Reduction of Emissions
Equipment in Percent
1. Overfire air jet system 40
2. Overfire air system plus auxiliary burner 62
3. Items 1 and 2 plus wet or dry cyclone 85 - 90
collector
4. Above items 1 and 2 plus wet scrubber, 94
impact or plate type
5. Items 1 and 2 plus electrostatic 99
precipitator, bag filter or
venturi scrubber
The installed cost of adding items 1 and 2 ranges between $1,500 and
$2,000. Items 3 and 4 would cost between $5,500 and $8,500. Item 5
ranges from $12,000 to $15,000 based on what little data is available.
Conversion of single flue incinerators to the double flue type should
be done whenever possible, as the separation of refuse charging and
gas emission flues has been found to be very beneficial.
Accomplishing the above items in a practical and economical manner is
fully covered in Reference 4.
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SECTION VI
PERFORMANCE STANDARDS
Satisfactory performance of new incinerator installations may be accomplished
by the use of either of .several types of filing requirements, such as
performance standards^ or construction specifications, or possibly a
combination of the two. In the former, minimum requirements are prescribed,
such as fly ash, smoke and other emissions, as well as unburned combustible
in the residue, while in the latter, specifications covering furnace
dimensions and construction, flue sizes, controls and air pollution removal
equipment, are established. In either case, complete filing of plans and
details is necessary.
Many localities permit installation in accordance with the filer's plans
and specifications, subject to final approval upon completion of satisfactory
performance tests, or based on previous tests of prototypes. In some cases
the manufacturer's guarantee may be accepted, tests to be required only if
violations are experienced. Usually the cost of such tests must be paid
by the installer rather than by the control agency.
Incinerator emission tests are relatively expensive and require specialized
equipment and personnel. The cost will range from $500 to several thousand
dollars and take from one to several days for preparation, setting up
equipment, and actual testing which should be done as closely as possible
under normal operating conditions and at the design capacity.
Development of continuous monitoring devices which is now underway to a
limited extent, will aid both the operator and the control agency. The
former now has no way of telling whether or not the incinerator emissions
are excessive, while the latter can vouch for performance only at the time
of his visit. The value of indicating and recording instruments would be
to show whether or not a new installation was ready for approval and to
determine the validity of complaints which at present is often difficult
or impossible to resolve. A project or grant for research to aid in the
development would be desirable.
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SECTION "VII
CONSTRUCTION SPECIFICATIONS
These specifications are similar to the specifications issued by architects
or consulting engineers and are in accord with building and equipment codes.
Construction specifications have been developed through the years to set
up minimum standards that will assure satisfactory performance, regardless
of variations in the details of construction of the several bidders.
Rather than being restrictive, a well developed and flexible construction
criteria benefits the manufacturer of adequate, well constructed and possibly
more expensive designs by setting up the minimum requirements that will be
accepted. Such criteria are also helpful in examining and approving
applications, reducing the possibility of one examiner in the control
agency turning down a design which another examiner might have recently
approved, based on inadequate knowledge or experience.
It should be noted that approval of an application under the above system
does not relieve the filer or user of the equipment of responsibility for
satisfactory performance as the best of equipment must be properly operated
to avoid violations.
An example of the implementation of the above is shown in the "Criteria for
Apartment House Incinerators"^ currently in use in New York City. Similar
criteria are issued by a number of air pollution control agencies in cities
such as Los Angeles, Chicago and Milwaukee.
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SECTION VIII
REFERENCES
1. Kaiser, E. R. New York University College of Engineering. Performance
of a Flue-Fed Incinerator. Technical Report 552.1, 1958.
2. New York City Housing Authority, Project Statistics, June 1966.
3. New York City Department of Air Pollution Control. Apartment House
Incinerator Criteria, March 1966.
4. New York City Department of Air Pollution Control. Criteria Used for
Upgrading of Existing Apartment House Incinerators^ May 1966.
5. Incinerator Institute of America - IIA Incinerator Standards, 1966.
6. Mayor's Task Force. Freedom to Breathe. Report on Air Pollution in
the City of New York, June 1966.
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PART 4
A REVIEW OF THE STATE OF THE ART OF
MODERN MUNICIPAL INCINERATION SYSTEM EQUIPMENT
Prepared by
David R. Pearl
Manager
Product Diversification Department
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. INTRODUCTION 1
II. CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE ACTIVITIES 2
III. ELEMENTS OF AN INCINERATION SYSTEM 3
A. REFUSE RECEIVING FACILITIES 5
B. REFUSE MEASURING EQUIPMENT 6
C. STORAGE OF REFUSE 7
D. SORTING, MIXING AND PREPARING THE REFUSE 8
E. FEEDING REFUSE TO THE FURNACE 9
F. DRYING AND IGNITION OF REFUSE 11
G. BURNING THE REFUSE 12
H. DISSIPATING THE HEAT OF COMBUSTION 17
I. COLLECTING, COOLING AND REMOVAL OF RESIDUAL SOLIDS 18
J. CLEANING AND DISCHARGING EFFLUENT GASES AND LIQUIDS 21
K. CONTROLLING THE PROCESS FOR SAFETY, EFFICIENCY, ECONOMY
AND COMMUNITY ACCEPTANCE 25
L. PROTECTING THE PERSONNEL AND EQUIPMENT 27
IV. FUTURE DEVELOPMENT IN MUNICIPAL INCINERATORS 30
A. RECEIVING, MEASURING AND STORING 30
B. SORTING, MIXING, FEEDING 31
C. FURNACES 31
D. DISSIPATION OF THE HEAT OF COMBUSTION 33
E. HANDLING OF RESIDUAL SOLIDS 33
F. AIR POLLUTION CONTROL 34
G. CONTROLS AND INSTRUMENTATION 35
H. PROTECTION OF EQUIPMENT AND PERSONNEL 36
V. REFERENCES 37
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SECTION I
INTRODUCTION
The objective of this section of the report is to describe the construction
and operational principles of the various kinds of equipment and systems
currently in operation or on contract for the central incineration of mixed
municipal solid refuse in the United States. Much of the material presented
here has previously been published in technical references listed in the
bibliography. However, this essay will attempt to organize the information
and present it with an explanation of technical terms and trade jargon so as
to make it most useful to non-technical decision makers. In addition, the
apparent problem areas and future technological trends, as disclosed in
interviews with leading incineration engineers, operators and manufacturers
will be discussed.
The purpose of incineration is the thermal reduction of wastes to a small
volume of inert solids and the conversion of the rest of the material to
innocuous gases. The essence of the ideal incineration process is combustion
(burning) , in which the hydrocarbon compounds of the combustible refuse
combine chemically with the oxygen of the air to form carbon dioxide and
water, and leave the minerals and the metals as solid residue. This chemical
reaction, called oxidation, releases heat energy which can sterilize the
residue, destroy odorous compounds in the refuse, and convert the water into
vapor, which, together with the carbon dioxide becomes an acceptable and
invisible part of the atmosphere.
Like any other chemical process, if the constituents are not intimately
mixed in the proper proportions, and if they are not sustained at the proper
temperature for the proper length of time, the reaction will be incomplete,
and undesirable products and effects may result. An uncontrolled rubbish
fire which causes smoke, airborne particulate matter, odors and putrescible
residue is an example of incomplete combustion.
For nearly one hundred years, engineers and technicians have been developing
the art of incineration of solid wastes in equipment designed for this pur-
pose. It has become evident that if the goals of efficient, sanitary and
acceptable refuse volume reduction are to be achieved through combustion,
the entire incineration process, from the receipt of the refuse to the
discharge of clean gas and sanitary residue, must be considered as an
integrated system.
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SECTION II
CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE ACTIVITIES
Municipal refuse incineration equipment and systems have been developed
and demonstrated to perform the necessary thermal reduction function
efficiently, reliably and economically. Further fundamental technological
"breakthroughs" are not required to provide satisfactory incineration service
to municipalities. Modern system engineering can do it if the following
principles are observed.
A. Standards of performance, expressed in clear, quantitative engineering
terms must be created and acknowledged. The fear that municipal mixed
refuse is so variable that standards are impossible has been allayed by
several studies which have shown that most refuse can be defined
within reasonable ranges of chemical and physical terms. Incinerator
performance can be based on refuse in these ranges with the occasional
excursion outside these ranges handled by special control equipment.
B. Specifications for procurement of incinerators should be expressed in
terms of engineering performance and not in terms of ambiguous
perfection ("shall be odorless, smokeless and perform to the satisfaction
of city officials") nor in terms of equipment dimensions and materials
("furnace shall be xxx inches wide and refractories shall be of xxx
material").
C. Methods of testing performance to specification must be established,
acknowledged and implemented. Statistically reliable tests of refuse,
flue gas and residue composition, tests of system capacity and of power
and water used are expensive and are therefore often curtailed to the
point that true system performance is not known. There is need for
development of simplified test instrumentation and techniques, and
perhaps for Government financial support of incinerator acceptance
test programs.
D. Economic consideration should be given to total cost evaluation,
including the sum of capital investment, operating costs and maintenance
costs to meet specified performance for the life of the investment,
rather than to simple consideration of lowest first cost for each
separate item of equipment.
E, Unification of responsibility for incineration system design, con-
struction and performance is necessary with the assurance of standby
financial resources to "debug" and develop new incinerator system
installations until they are performing to specification. A Government
supported insurance program, rather than present punitive performance
bond arrangements might be a constructive approach.
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SECTION III
ELEMENTS OF AN INCINERATION SYSTEM
Many systems of incineration have evolved over the years as technology
improved, as living habits changed, and as solid waste collection practices
developed. Although considerably different in construction and operation,
it is clear that all successful systems of central municipal mixed refuse
incineration include provisions for carrying out the following essential
functions:
1. Receiving loads of mixed refuse at varying rates of supply.
2. Measuring the quantity of refuse received.
3. Storing a "buffer" amount of refuse in a sanitary, accessible,
yet nuisance-free manner.
4. Sorting, mixing or otherwise preparing refuse for incineration.
5. Feeding the refuse to a furnace at a controlled rate.
6. Drying the refuse sufficiently to permit ignition of combustibles.
7. Burning the refuse to produce essentially inert solid residue
and tolerable gases.
8. Dissipating the heat of combustion.
9. Collecting, cooling and removal of non-combustible residual solids.
10. Cleaning and discharging effluent gases and liquids in an acceptable
form.
11. Controlling the process for safety, efficiency, economy and com-
munity acceptance.
12. Protecting the personnel and equipment from the elements, from
dangerous refuse and from careless operation.
Before proceeding to the description of the principles of the equipment used
to perform each of the above twelve functions, it is necessary to clarify
the popular method of "rating" modern municipal incinerators, since often
there are different kinds of equipment used for different size-rated incin-
eration systems. It has become common practice to rate municipal incinerators
in tons of burning capacity per 24 hour day. This is an unfortunate and
often ambiguous scale of measurement, because a ton (2,000 pounds) of mixed
refuse may easily have as much as 50 percent variation in its heating
value (Btu/pound) due to different amounts of paper, plastics, wood, vegetable
matter, moisture, cans and bottles, etc. (The effect of variation in heating
value on the effective capacity of an incinerator is discussed in another
section of this report.) Also, in the absence of uniform standards for
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ELEMENTS OF A MUNICIPAL REFUSE INCINERATION SYSTEM.
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measuring the degree of completeness of combustion, the "capacity" in tons
per day burned in a given incinerator may be considerably increased if less
complete combustion is accepted. Furthermore, relatively few incinerators
are operated for full 24 hour days, and the starting up and shutting down
operations, at partial load, lead to confusing concepts of the amount burned
"per day". Nevertheless, it does not appear likely that the tons per 24
hour day (TPD) method of rating will be easily changed, so it will be used
as a classifying parameter in this report.
Municipal incinerators have been built or offered in size ranges of 30 to
1,200 tons per day (TPD). In all but the smallest installations, it is
considered desirable to provide at least some measure of duplication of
important pieces of equipment, so that a single "outage", whether due to
equipment breakdown or normal maintenance, will not prevent the plant from
operating at partial capacity. Generally, the larger incinerator plants
consist of groups of two, three or more 150 TPD to 500 TPD furnaces fed by
a common loading system, with either common or separate gas and solid residue
discharge systems.
A. REFUSE RECEIVING FACILITIES
In the United States, practically all refuse is delivered to central
incinerators by motor vehicles, usually in "packer" trucks of 16 to 26
cubic yard capacity which results in loads of three to six tons of
moderately compacted refuse. The more modern packers have means for
mechanically ejecting these loads onto a level floor or into a pit, but
many of the older types dump their loads by tilting the truck body so
the refuse slides out the back. These are suitable for dumping
(tipping) their loads into a pit, but may not eject their entire load
onto a level floor unless the truck is driven forward with the body
tilted. Many smaller communities, and larger communities in emergency
situations, still use standard three to five cubic yard open dump
trucks for refuse delivery, and in the aggregate, there are many
deliveries made by all sorts of private vehicles5 ranging from the family
sedan with a pail of refuse in the trunk, to light trucks with crates
of refuse or old furniture, to large vans loaded with special industrial
wastes.
The receiving facilities of modern incinerators are designed primarily
to accommodate packer trucks, but they must also be able to handle the
other types of vehicles. There are two principal types of receiving
stations:
1. The floor dump, which is an open paved floor area on which the
trucks deposit their loads. A tractor then pushes or lifts the
refuse into conveyors or feed hoppers or piles the refuse in
storage heaps for later disposition.
2. The bin dump which is a concrete lined pit with a curbing at one
edge to which trucks can back their rear wheels and discharge the
load to a level below grade, from which it is later lifted by a
crane.
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Although there is much to be said in favor of enclosed tipping areas
protection from the elements, reduction of windblown refuse, contain-
ment of noise and odor and night storage of vehicles a significant
number of incinerators, in the interests of low first cost, make do with
only a canopy over the tipping bays, or nothing at all.
Traffic control and personnel safety are important considerations with
heavy trucks backing into close quarters to dump their loads, and many
receiving areas attempt to provide multiple dumping areas (three to six
bays usually) to handle peak delivery loading, and separate exits so
the "empties" don't have to thread their way back through incoming
traffic. Sometimes a special bay is reserved for cars and light
trucks to keep them out of the way of the big packers.
B. REFUSE MEASURING EQUIPMENT
Refuse received at a municipal incinerator is usually measured by weight,
by volume, or by number of delivery vehicles, in order to:
1. Compare performance against system rating.
2. Establish patterns of refuse receipt for planning purposes.
3. Measure the quantities and rates of refuse collection from a con-
trolled area.
4. Establish a basis for service charges to various sources of
refuse.
5. Detect unusual or undesirable loads.
The most common method of measurement is by weighing on a truck scale
which is usually located so that all incoming vehicles must cross it to
reach the tipping floor or bins. The weighing equipment varies from
direct reading mechanical scales to the more sophisticated scales
including load cells, remote indicators and automatic print-out devices.
Usually, the scale is attended by a weighmaster who checks the
credentials of the reufse truck driver. Many incinerators restrict
their service to specific towns, licensed private collectors, home-
owners who have obtained a permit, etc. He checks the empty weight of
the vehicle, and inspects the load for obviously undesirable refuse like
demolition masonry, logs, large metal home appliances or explosives
which may damage the incinerator.
The newest weighing systems can be made fully automatic so that the
driver of the incoming vehicles inserts a coded license card or key in
a box to open barrier gates, and the load is weighed, recorded and
admitted to the dumping floor, and finally the empty truck is weighed and
released through another barrier gate, all without need for a scale
attendant.
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In some cases, the scales are used to record weights of loads of brush,
furniture, home appliances and other refuse which is taken directly to
a land fill.
Another method of weighing is by use of a load cell on the bucket
suspension of the travelling crane. This can accurately measure the
weight of refuse actually fed into the incinerator furnaces. However,
it affords no control over the amount of refuse received from each
incoming truck.
Residue leaving the incinerator is usually measured by estimating volume,
if it is measured at all. In most cases, the residue is wet from the
quenching process, and the amount of water is quite variable, so weight
measurements are not considered reliable indications of the residue
weight. The residue is frequently carried off to a land fill in open
body dump trucks of three to five cubic yard capacity, and it is there-
fore measured by the number of truckloads. If a sample is dried and
weighed, the volume estimate can be converted to weight in order to
calculate the average percent reduction of incoming refuse weight.
C. STORAGE OF REFUSE
It is accepted practice to collect refuse during the daylight hours, and
since collection trucks start their rounds about the same hour, and are
filled about the same hour, refuse is likely to arrive at the incinerator
in cycles, with two or three peak periods during the day. Where the
incinerator operates more than one shift, or more days than the
collection service, the refuse collected must be stockpiled for
burning over an extended period. Also, in case of incinerator shut-down
for maintenance or repairs, or in the event of holidays, disasters or
other causes of generation of large quantities of waste material, there
is need for the incineration plant to accept and hold quantities of
refuse until it can be handled by the incinerator working at its steady
rating.
The most common storage device is the concrete bin, set below ground
level so that trucks can dump directly into it. Bins are usually
constructed of reinforced concrete and often have steel rails or facings
set in the sides to resist damage from the crane buckets. Unfortunately,
incinerators are often erected on otherwise marginal land which may be
poorly drained or may be the site of an old refuse dump. This can
lead to expensive construction of the bins as well as expensive
foundations for the rest of the structure. The bins must be water
proof, yet must be provided with sewers for draining of accumulated
liquids or flushing water.
Bins tend to be large. For example, the bin for a 500 TPD plant with
provision for one full day's storage when filled up to ground level, and
one and one-half day's storage with refuse piled by the crane, might
be about 75 feet long, 25 feet wide and 50 feet deep . For a 1,000 TPD
plant, the change would probably be mostly in increased length.
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Bins are usually carefully shaped to permit full access by overhead
cranes, and to facilitate cleaning. Since dust, odors and fires have
been recognized as problems, some bins are equipped with sprinklers,
ventilation suction systems and doors to close them off from the drive-in
and tipping areas.
The other storage method, the floor dump, is not nearly as common as
the bin, and appears to be used only in smaller incinerators. It con-
sists of a concrete or bituminous surfaced floor sheltered-or enclosed
by a simple structure. A bulldozer equipped with a lift bucket is
used to move and pile the refuse on the floor, sometimes ten feet high,
until it is fed into the incinerators. The sides of the enclosure are
constructed to withstand the side thrusts of the refuse piles, and there
are sewers for drainage and often sprinklers and ventilation systems
to cope with dust, fire, and odor.
In case of temporary emergencies, excess refuse is sometimes piled
outside the tipping floor, or is taken directly to a land fill, until
floor or bin space becomes available.
D. SORTING, MIXING AND PREPARING THE REFUSE
Some communities attempt to segregate refuse during collections, while
others take anything that will go into a packer truck. Still others
bring furniture and large metal objects like refrigerators, stoves,
bedsprings and bicycles to the incinerator. Sometimes there are
commercial wastes like large packing crates, or industrial wastes like
large wooden pallets, or rubber tires, or spoiled batches of food-
stuffs. Occasionally, non-combustibles like concrete slabs, or china
sinks or rolls of fence wire appear. Obviously, certain of these items
should be kept out of an incinerator, while others must be treated
in some special way to get them into and through the incinerator with-
out causing damage.
Gross separation of objects unsuited for incineration is done by watchful
weighmasters and furnace loaders. Breaking or crushing of bulky
combustible items like furniture and crates is often done by the travel-
ling crane or the bulldozer, whichever is used in the particular plant.
A few incinerators are equipped with chippers, wood hogs or hammermills
for disintegrating pallets, demolition lumber and logs. The resulting
"chips" are then mixed in with the rest of the refuse going into the
furnace. Those disintegrators that are acceptable for this severe
service are very heavy duty machines provided with large throats to
receive large items. They generally require more than 50 horsepower
and are quite noisy. The unavoidable inclusion of metals and stone in
the refuse takes a heavy toll of the knives or hammers of the machines.
Nevertheless, they are very effective toward making bulky items suit-
able for incineration and thus saving land fill.
The problem of unusually "wet" refuse like lawn clippings, or spoiled
loads of fruit; or of high heating value refuse like plastic scrap or
rubber tires is handled by judicious mixing on the tipping floor or in
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the storage bin. The crane operator or bulldozer operator tries to
"average out" the unusual loads, into a reasonably combustible mix.
E. FEEDING REFUSE TO THE FURNACE
Moving the refuse from the place it is stored to the inside of the furnace
is an unusual and exacting materials handling task, for which several
types of specialized equipment have been developed. The task is
difficult because the material to be handled is composed of so many
different sizes, shapes, weights, textures, hardnesses, slipperiness
and resiliencies. There is paper in all forms, from telephone books
to carton boxes to greasy garbage wrappings. There is cloth, wood,
pieces of metal machinery, all shapes of cans and bottles, grass and
brush clippings, earth, dust and occasionally significant amounts of
waste foodstuffs. In good weather, the conglomerate waste (mostly
paper) may be quite dry and fluffy, but during prolonged rainy spells,
or in snow storms, the refuse received at the incinerator may be soggy
wet. Also, the service imposed on the material handling equipment can
only be classified as "severe".
The refuse, while generally lightweight when compared to earth or
minerals, nevertheless is handled in such large volumes and by such
large equipment that high tonnages must be grasped, pushed, lifted,
and carried. For example, a typical crane bucket, large enough to
"grab" 1,000 pounds of mixed refuse at a "bite", weighs about 5,000
pounds in itself, in order to withstand the jarring, abrasive service
conditions. Hence, the crane and its drums, bearings, cables, motors,
gears, brakes, etc. must all be designed to lift 6,000 pounds each time,
and to do it continuously and reliably. Similarly, a tractor used to
push and stack refuse on a charging floor might handle over 1,000 tons
per day, in the course of feeding 500 tons per day into the furnaces.
Another requirement of the feeding system is to supply a controlled
flow of refuse to the furnaces with minimum interference with air supply
for combustion, and with maximum protection against flashbacks of fire
or gases through the charging opening.
The most popular feeding system, by far, is comprised of a below-grade
storage bin and a travelling crane with a grab bucket which lifts and
carries the refuse high above the furnace, and releases it into a funnel
shaped hopper which leads to a chute that allows the refuse to slide
into the furnace under the action of gravity. A few smaller incineration
plants use monorail hoists in which a single fixed overhead "rail"
supports a "trolley" which can travel the length of the rail on wheels.
The trolley contains electric motors and brakes, and drums of steel
cable which suspend and raise and lower a "clamshell" type bucket or
grapple, usually two to four cubic yard capacity, over the refuse
storage bin. (The halves of a bucket may be visualized as two cupped
hands with the fingers of each tight together, while a grapple would
look like two hands with the fingers spread apart in a claw configuration.)
With monorail cranes, the bin is narrow with steep sloping sides to
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make the refuse fall under the line of travel accessible to the bucket,
and the furnace feed hoppers must also be in this line of travel, to
accept the refuse from the crane.
The larger incinerators have bridge cranes in which two parallel over-
head rails mutually support a cross structure, or bridge, on wheels,
so the bridge can travel the length of the rails. The bridge, in turn,
supports a "trolley" which suspends and operates the bucket or grapple
as described above. The bucket of the bridge crane can reach any
point in the area between the support rails and can therefore handle
refuse in wide bins and can reach furnace charging hoppers in more
locations. Usually, the crane is operated by a man in a cab mounted
right on the bridge or trolley. The cabs are well ventilated, often
air conditioned, and are frequently provided with communications systems,
since the operator must work in an environment of dust, odor, heat and
noise, yet his judgment and performance in sorting and mixing refuse,
and rate of feeding the furnaces are extremely important to the success-
ful operation of the incinerator. A few cranes are operated from a
fixed "pulpit" on ground level or above, and some monorail types are
controlled by a man walking on the ground alongside the trolley and
using electrical switches on the end of a cable, or mechanical controls
activated by a rope.
Good cranes are costly equipment because of the sophisticated controls,
the severe duty and the need for reliability, since a crane stoppage
shuts down the entire plant. They also require special provisions in
the buildings which house them, such as strong, true mountings for the
rails, headroom and side clearance for the trolleys and bridges, heavy
duty, well protected electrical power source to the trolley (either the
"third rail" type or festooned retractable cables) , and sometimes
storage space for standby bridges, trolleys and buckets.
Tractors with bulldozing blades and lifting buckets are simpler and
less costly than travelling cranes, but they can only be used to feed
a furnace hopper where the refuse does not have to be taken out of a
below-grade bin, and lifted above the furnace. If a tipping floor
is at an elevated level with respect to the furnace, as is possible with
a hillside location or with a manmade ramp, the tractor operator can
mix, sort and feed refuse to a bank of incinerators just as efficiently
as a crane operator, and, in case of a breakdown, the machine can be
quickly replaced with another tractor, or even, temporarily, with a
snowplow on a truck.
C ontinuous chain, bucket or belt type conveyors appear to be rarely
used in feeding incinerator furnaces. This is not because of inability
to transport the waste material, but is perhaps due to the dismal
prospect of a disabled conveyor buried 50 feet deep under 500 tons of
mixed refuse, or to the inability of a single conveyor to stack and
mix refuse like a crane or tractor can do. In at least one small
incinerator, a tractor is used to push refuse from a tipping and
sorting floor into a shallow floor trench onto an apron type metal
conveyor which carries the refuse up an incline into the furnace.
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In some older types of furnaces, the refuse is charged directly through
an opening in the top of the furnace and falls on the firebed. Such
openings are usually fitted with refractory lined horizontally sliding
charging gates, often hydraulically activated, located just below the
charging hopper. A load of refuse from crane, dozer, or directly from
a truck is dumped into the hopper and covers the charging gate. When
the gate is withdrawn horizontally, the load of refuse forms an air
seal until it falls into the furnace, and then the charging gate is slid
back to its closed position as quickly as possible. This type of batch
feeding permits a quantity of cold air to enter the furnace with each
charge and can lead to erratic combustion and smoking. A true air lock
can be achieved with two sliding charging gates, one above the other,
but this appears to be rarely used.
The most frequently used charging method consists o-f a smooth metal
lined chute extending several feet down from the "throat" of the hopper
into the furnace, and terminating above one end of the stoker or hearth.
The resultant column of refuse forms an air seal, and the lower end of
the column of refuse is exposed to the heat of the furnace for drying
and ignition. The stoking action starts the ignited refuse on its way
through the furnace, and new refuse from the column replaces it. The
"buffer" quantity of refuse in the chute and hopper permits the actual
feed rate into the furnace to be controlled by the stoker action and
allows the crane to be used for stacking refuse or feeding other furnaces
for reasonable intervals of time.
The end of the chute in the furnace is water cooled or refractory coated.
To cope with occasional backfires of the refuse in the chute, the hop-
pers for these chutes are either equipped with sliding charging doors
at their throats or with metal covers which can be quickly applied to
seal them off.
An innovation to the gravity fed chute has been the addition of an
hydraulically activated horizontal ram at the bottom of the chute to
push "slugs" of mixed refuse into the furnace. This affords positive
control of the feed rate and serves as the chute seal in place of the
charging gate. The ram is arranged so as to push a load of refuse onto
an exposed drying and ignition hearth, and in the next stroke, the new
load tumbles the dried refuse over a parapet onto the actual stoker.
DRYING AND IGNITION OF REFUSE
Most materials that truly burn, i.e., combine with oxygen, must first
be converted to their gaseous form by heating. Much of the material in
mixed refuse has moisture on it (surface moisture) or absorbed in it
(inherent moisture), and any heat that is applied first turns this
liquid water to steam but leaves the burnable material too cool to
volatilize and ignite until most of the water has been driven off. To
perform the drying function and to prevent smothering a going fire with
undried and non-combustible material, most furnaces have some provision
for exposing newly charged material to radiant heat energy and hot gases
to drive off and absorb the moisture. As previously mentioned, these
provisions take the form of exposure at the bottom of a feed chute, or
on a drying stoker or hearth, or brief suspension in hot gas as the
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refuse falls onto the stoker through the opening in the roof of an
incinerator furnace.
After the moisture has been driver, off, the heat radiated to the refuse
by the hot gases and hot surfaces, and conveyed to the refuse by the
motion of hot gases, increases the temperature of the refuse until the
hydrocarbon compounds vaporize and decompose and begin to combine with
oxygen. This is the ignition process which starts the burning. In
most furnaces, the original ignition is done by a match or a pilot oil
or gas burner, and thereafter the burning refuse ignites the incoming
refuse. Subtile design features like positioning of grates with respect
to heat reflecting walls, or guiding of flaming gases over the incoming
refuse, are employed to ensure autoignition. In some furnaces, to
ensure ignition when there are unusually wet loads, auxiliary gas or
oil burners are positioned to play their flames on the incoming refuse.
During the drying and ignition phase of combustion, there are large
quantities of steam and gases liberated and the fire heats and expands
these to many times their original volume. Therefore, furnaces usually
provide for unrestricted flow of these gases away from the ignition
zone, so that fresh air can get in to supply oxygen and prevent smothering
of the flame.
G. BURNING THE REFUSE
The burning process consists of the continued heating and vaporizing
of the elements that will combine with oxygen until only inert minerals
and metals remain as ash. Actually, there are many additional complex
reactions during burning, and most of the metals actually oxidize to
some extent, as do other elements like sulfur and even nitrogen in the
intense heat of the furnace, but these are minor effects and would only
confuse the general picture if discussed here.
The heart of the incineration system is the furnace, which consists of
a chamber to contain the gaseous reaction, a stoker to transport the
refuse through the furnace and agitate the refuse to expose new surface
to oxygen and heat, an air supply to furnish oxygen for combustion, and
a pressure differential (draft) to cause the gaseous products of
combustion to flow out of the chamber.
Furnaces come in many shapes and sizes, but the three most common con-
figurations in modern municipal incinerators are the upright cylindrical
(like an oil drum), the rectangular (like a shoe box) and the multi-
chamber rectangular (like two shoe boxes joined, with one lying flat
and the other on end). They are generally constructed on concrete
foundations with either a structural steel framework supporting inner
walls and roof arch of refractory material, (supported wall and
suspended arch construction) or typical masonry with bricks laid one
atop another (gravity walls) and self supporting arched roofs made of
keystone shaped bricks (sprung arches). The supported wall and
suspended arch are almost universally used in modern incinerators.
Metal or refractory hooks secure the refractory to the structural steel,
and a layer of insulation and an outer sheet metal casing usually
complete the wall structure.
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Three different forms of refractory are used; fired refractory bricks,
which are laid up with a very thin layer of refractory cement between
bricks, plastic refractory which is supplied in a damp clay-like con-
sistency and is spread and pounded into place against lath or hooks,
and castable refractory which is poured into temporary molds, like
concrete. The latter two forms are usually dried out at low furnace
heat and then assume their final vitreous strength when the furnace is
brought up to its normal operating temperature. There are many com-
positions of refractory material, basically clays of silica or alumina.
These are called fire clays and are used in various grades for various
conditions of heat, erosion, and chemical resistance. Special high
performance refractories like silicon carbide or aluminum oxide are
used for extremely severe duty such as furnace linings at the edges
of the stoker bed where there is intense heat and severe abrasion.
In practically all municipal incinerators, the refuse rests on grates
while burning. These grates are, in general, metal surfaces with
holes or slots through which combustion air enters. Usually the grates
are movable by mechanical means so they can move the refuse through
the furnace, agitate the refuse to promote combustion, and remove the
ash from the furnace. These mechanical grate systems are called
stokers, since they perform the function which used to be done by men
who tended the fire using long metal hoes and stoking bars. Most
furnaces are equipped with doors in the sides through which manual
stoking can be done when necessary.
Upright cylindrical furnaces have a floor of rocking grates above the
ash pit. These rocking grates are pivoted on axles so that when they
are rocked, large spaces open up for the ash to fall through. Above the
floor of grates, mounted on a vertical axis, is a star shaped rabble
arm which rotates slowly and spreads and tumbles the refuse on the grate
during combustion. In these furnaces, new batches of refuse are dumped
in from the top at intervals, and they are, therefore, classed as
batch type furnaces.
The flow-through furnaces are equipped with stokers which receive refuse
at one end, either continuously or in batches, and continuously move it
horizontally and downward through the furnace, finally depositing the
ash in a receiver at the opposite end of the furnace. During the journey
through the furnace, the refuse is supplied with "underfire air" which
comes up through the grates from a "windbox" under the stoker. Fine
particles of ash (siftings) often fall through the holes in the stoker
surface and must be caught and removed to avoid eventually clogging the
windbox and the grate openings.
There are four principal types of flat-bed stokers:
1. The travelling grate stoker which is essentially a moving chain
belt carried on sprockets and covered with separated small metal
pieces called keys, so that the entire top surface can act as a
grate while moving through the furnace, yet can flex over the
sprocket wheels at the end of the furnace, return under the furnace,
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and re-enter the furnace over a sprocket wheel at the front. The
sprockets drive this chain conveyor, and are in turn driven by
electric motors at slow speed.
2. The reciprocating grate stoker, which is a bed of bars or plates
arranged so that alternate pieces, or rows of pieces, reciprocate
slowly in a horixontal sliding mode and act to push the refuse along
the stoker surface. These are driven through links by electric
motors or hydraulic cylinders.'
3. The rocking grate stoker which is a bed of bars or plates on axles
so that by rocking the axles in a coordinated manner, the refuse is
lifted and advanced along the surface of the grate. This type of
stoker is actuated by linkage driven by hydraulic or electric motors.
4. The inertial grate stoker, which is a fixed bed of plates with the
entire bed carried on rollers and activated by an electrically
driven mechanical drive which draws the bed slowly back against a
spring and then releases it so that the entire bed moves forward
until stopped abruptly by another spring. The inertia of the
refuse carries it a small distance forward along the stoker surface
and then the cycle is repeated.
Each of these types of stoker may be flat or inclined down in the
direction of flow, and may be used as a single stoker or as a series of
two or three units arranged in stair-step array so the refuse is tumbled
and agitated as it moves from one section to the next. Often the
individual sections can be operated so as to advance the refuse at
different speeds to control drying and burn-out of the refuse.
The grate surfaces are made of sturdy iron or steel castings, alloyed
and designed to resist distortion, growth, cracking and oxidation.
However, in well designed furnaces, the grate surfaces do not
characteristically operate at temperatures even near that of the fire
because they are protected by unignited refuse, by ash, and by the
cooling underfire air passing through them. In the drying and ignition
zones, the volatile combustible gases, water vapor and smoke are driven
off and flow into the secondary combustion chamber where they are mixed
with air and retained long enough to complete combustion. After the
ignition zone of the stoker, the residual refuse burns off its fixed
carbon with a clean hot flame which radiates heat energy to facilitate
the proper burning of the still-combustible gases and airborne particulate
matter.
The rotary kiln is really a combination furnace and stoker and is very
effective in gently tumbling the burning refuse until complete com-
bustion is achieved. The kiln is a large metal cylinder with its axis
horizontal or slightly inclined. It is lined with firebrick and
mounted on rollers so that electric motors can slowly rotate it about
its horizontal axis. As used in municipal incinerators, the refuse
is always first passed over flat bed type drying and ignition stokers
in a furnace, and then, when most moisture and volatile constituents
have been driven off, the burning residue is fed into the kiln for final
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burn-out. In such an arrangement, the volatiles driven off in the
ignition chamber are led through a passage above the rotating kiln
and join the hot gas effluent from the kiln in a secondary combustion
chamber where combustion of the gases and airborne particulate matter
is carried out.
Another kind of furnace which is acceptable to some municipalities is
the tepee burner. As the name implies, this is a large sheet steel
walled structure that looks like an Indian tepee with an opening at the
top to let the smoke out. Instead of stokers, these have either earth
or concrete floors, or sometimes fixed gratings with air supplies under
them. Refuse is fed in either by a conveyor which enters the tepee
half way up its side wall, or by a bulldozer which pushes the refuse in
through a ground level door, to make a heap in the center of the floor.
Residue is removed after the fire has burned out, by pushing it out
with the bulldozer.
A few cities have recently built a specialized type of incinerator for
burning logs, heavy brush and bulky objects like discarded furniture.
This has taken the form of a large box-like furnace with typical furnace
wall refractory and insulation construction, and large doors at one end.
The floor is a simple firebrick hearth and one end of the furnace is
constructed to collect the flue gases (the products of combustion) and
treat them in a cleaning process before release to the atmosphere. The
bulky refuse is pushed into the furnace by a bulldozer, ignited, and
allowed to burn down to residual ash which is cleaned out of the
incinerator by the bulldozer when the furnace has cooled.
Waterwall furnaces are one of the most recent innovations in municipal
incinerator design. It was recognized that incinerator furnaces differ
from other kinds of furnaces, in that ordinary industrial furnaces are
built to conserve all possible heat for useful purposes. Incinerator
furnaces burning American mixed refuse usually have excess heat which
causes slag (melted and recrystallized ash) to accumulate on the
refractory walls until it sometimes tears the walls down with its
weight. To guard against slag, or other heat damage to the furnace,
extra cooling air is introduced into the furnace, but this increases
the total gas volume that passes out of the furnace for cleaning, and
results in larger and more costly dust collectors, fans and stacks.
Waterwall construction consists of steel tubes laid side by side and
welded together to form panels which are in turn formed into the walls
of a furnace. Water is circulated through the tubes and absorbs heat
from the incineration process. The water may turn into steam or into
hot water, depending on the design, and this steam or water may be put
to a useful purpose, or simply used to carry the heat away to the out-
side environment. This construction reduces the necessity for excess
cooling air in the furnace, and as a result, the flue gas exhausting
and cleaning equipment can be smaller and less costly. A layer of
protective insulation and light metal sheathing is used outside the
waterwalls to conserve the heat in the tubes and to protect personnel
and adjacent equipment.
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In contrast to the "underfire" air which enters the furnace through
and around the grates, air which enters the furnace above the grates
through the sides or roof of the furnace is called "overfire air".
Overfire air is used to mix and burn with the combustible gases driven
off from the refuse, and to cool the burning gases to temperatures which
will permit reasonable furnace life. Overfire air is usually introduced
in high velocity jets at specific points which vary with furnace
design, and is directed so as to provide turbulence and thorough mixing
of the gases for optimum combustion.
The flow of air and other gases through a furnace is caused by blowing
the air in (forced draft), sucking the gases out so that atmospheric
air flows in through the openings provided (induced draft), or heating the
gases so they become lighter and rise (natural draft). Forced draft is
generally used for underfire air and overfire air jets in modern furnaces,
and is supplied by heavy duty industrial type fans driven by electric
motors and controlled by dampers which are simply gates or flaps in the
air ducts.
Furnace pressures are usually held slightly below atmospheric pressure
so that if doors are opened, or if there are any leaks in the walls,
atmospheric air will flow into the furnace, rather than permitting the
hot, odorous and sometimes dangerous gases to flow out of the furnace to
the surrounding workspace. This "negative draft" is maintained by sucking
out slightly more gas than the air and gases that are blown in or
generated in the furnace. The traditional way to do this is by natural
draft, utilizing a tall stack. The heated gases in the stack are
lighter than the cooler atmospheric air outside the stack, and so a
positive upward gas flow is established by the same principle as sucking
up liquid through a straw. Stacks are popular because they are simple
and can be constructed to handle large volumes of gas and to withstand
hot and corrosive gases. Also, they discharge the airborne products of
combustion high in the atmosphere where the winds can quickly disperse
them. After the first cost of erection, they require no further expense
for power and usually need only nominal maintenance. However, there are
practical limitations on the heights and costs of stacks, and these,
in turn, limit the amount of suction available to draw the flue gases
through efficient dust collection devices. For these reasons, the newer
incinerators include induced draft fans which can provide almost any
degree of suction required for good gas cleaning.
Induced draft fans, while usually less costly than a natural draft
stack, are limited by their tolerance to hot and corrosive gases so that
normally the gases are water cooled before the fan. The fans are usually
quite large and require large electric drive motors which use considerable
power. They can exhaust into relatively short lightly constructed
stacks which serve only to carry the residual gases and particulates to
a reasonable dispersal height. Sometimes provision is made for varying
the fan speed to control the gas flow through the furnace, but more
often dampers, which are less expensive, are used for this control.
The temperatures in a modern municipal incinerator furnace are controlled
between reasonably close limits. Average temperatures in the burning
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fuel bed on the grates, and just above, may reach 2,100°F to 2,500°F-
The temperature of the flaming gases falls from this level to about
1,200°F to 1,600°F in the time the gases flow through the primary and
secondary combustion chambers. Generally, the average gas temperature
of the furnace is kept above 1,400°F to ensure oxidation of all
malodorous compounds, and below 1,800°F to prolong the furnace life.
The secondary combustion chambers in incinerators are seldom sharply
defined chambers connected by passages to the primary combustion chamber.
Rather, they tend to be extensions or enlargements of the primary com-
bustion chambers sometimes set off by half-walls or baffles that cause
the gases to flow in turbulent eddys for a time long enough to complete
the combustion process.
H. DISSIPATING THE HEAT OF COMBUSTION
Early incinerators which had to burn refuse of low heating value were
designed primarily to conserve and reflect the heat of combustion so as
to dry and ignite the refuse and heat the resultant gases above the
deodorizing temperature with minimum use of supplementary fuel. The
acceptable limit on furnace temperature was then imposed by the durability
of the refractory lining. Hot flue gases were discharged directly
through masonry stacks with refractory linings, with a "settling
chamber" at the base and a "spark screen" at the top as the air pollution
control. Early attempts to use waste heat to generate steam were
unsatisfactory because there was relatively little "waste heat".
Modern municipal incinerators, burning refuse of much higher heating
value, and emitting their flue gases through sophisticated air pollution
control devices, are designed to dissipate the heat of combustion so
that after achieving the 1,400°F to 1,800°F necessary for complete
combustion in the furnace, the flue gases are cooled to 500°F to 700°F
before they enter the air pollution control devices.
The use of air cooled and water cooled furnace walls has been mentioned
previously. A full water wall furnace, or a waste heat boiler consisting
of an array of water tubes in the path of the hot gases, can bring the
flue gases down to 600°F and even lower, thus reducing their volume as
well as their temperature so that economically sized exhaust fans and
electrostatic precipitators, cyclones or bag filters may be considered.
The heat of combustion is transferred to the steam and the energy is
made available to do work.
Air cooled refractory furnaces have thus far been used mainly to prolong
refractory life and reduce slagging rather than to reduce flue gas
temperatures.
The two most common methods of reducing flue gas temperatures are by
dilution with ambient air and by evaporation of water directly into the
gas stream. In addition, there is always some direct conduction and
rediation of heat through the walls of the furnace and ducting. Direct
admission of air is a simple and easily controllable operation. A
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damper in the ducting allows outside air to be sucked into the flue
gases because the draft of the chimney or of the induced draft fan
causes a lower pressure inside the gas ducts than outside. However,
even though cooling the flue gases shrinks their volume, the amount of
fresh air added increases the net volume so that larger and thus more
costly ducts, fans, air pollution control equipment and stacks are
required.
If water is mixed with, or exposed to the hot flue gas stream, the water
tends to evaporate into steam, and in so doing withdraws heat from the
gas. In round numbers, the evaporation of one pound of water can lower
the temperature of 40 pounds of hot gas by 100°F. The total volume of
the cooled gas and the steam is less than the volume of the original hot
gas, so smaller fans, ducts and pollution control equipment can be
utilized. However, the water usually does not entirely evaporate and
the residual liquid absorbs sulfur and chlorine from the flue gases and
becomes acidic and attacks the metal mechanism and structure of the gas
cleaning equipment unless they are designed to resist corrosion. Often,
water quenching is combined with a wet scrubber for gas cleaning, since
the water supply, distribution and containment systems are common. The
quenching and scrubbing water may be introduced as sprays, on wet
baffles which are obstructions placed in the gas duct with water
flowing in thin films over the structures, or as wet bottoms, which are
simply shallow water tanks which form the bottom of sections of the flue
gas ducting. The effectiveness of evaporation cooling is usually
dependent upon good mixing of the gas and liquid.
I. COLLECTING, COOLING AND REMOVAL OF RESIDUAL SOLIDS
Solid residue is generated at three places in a municipal incinerator:
the incombustibles that come off or through the stoker, the sittings that
fall through the grate openings, and the fly ash collected from the flue
gas. Each of these solids occurs in different quantities and different
form, and since, on the average 20 percent to 25 percent of the weight
of municipal mixed refuse is glass, rock, cans and other metals and
minerals, the collection, cooling and removal of the incombustible solid
residue is a significant materials handling task. Fortunately, this
solid residue comprises only 5 percent to 15 percent of the average
volume fed into the incinerator, the rest having been converted to gas.
The principal residue is that discharged from the stoker. This consists
of broken glass and ceramics, tin cans of all shapes and sizes up to
oil drums, stones, earth, assorted hardware, some fused ash (clinkers)
from melted glass, metals and minerals, all surrounded by flakes and dust
of the light fluffy ash that typically results from burning paper or
wood. Although some incinerators do a remarkably thorough job of burning
the combustibles, practical limitations of the time that the average
load can be left in the furnace permit some incompletely burned refuse
to appear in the stoker residue. Telephone books, catalogs, and heavy
bundles of newspaper, particularly if wet, are not readily penetrated
by air for direct combustion, or by radiant or convective heat for drying
and volatilization, so it is not uncommon to find bits of unburned paper
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in the ash. Heavy timbers or green wood may pass through the average
40 to 60 minute burning cycle with a core of unburned wood still
present. Certain foodstuffs containing high water content and occurring
in thick sections, like watermelon rinds, carrots, apples or waste meats
may char on the outside and seal in liquids, thus permitting some
putrescible material to appear in the ash. All this may be aggravated
by an operator pushing wet refuse through an incinerator at maximum
feed rate to handle a peak load, instead of slowing the stoker ta
permit better drying and longer combustion time for difficult wastes.
Nevertheless, a typical "good" residue contains less than 5 percent by
weight of unburned carbon and less than 1 percent of putrescible
organic material.
In cylindrical batch feed type furnaces, the stoker residue falls into
refractory lined metal hoppers where it is quenched, then through a
gate in the bottom of each hopper, into a truck for removal to a dumping
site. The residue is usually steaming and sometimes still burning
locally when it is removed, because of the difficulty of reaching all
the internal surfaces with the water sprays.
The larger, newer incinerators with flow-through furnaces generally
use conveyor systems to remove the stoker ash. The residue is usually
discharged from the stoker grates into a water filled trough where it is
thoroughly quenched and cooled. A metal drag link conveyor, consisting
of a pair of endless metal chains with metal bars attached between the
chains, like a rope ladder, is driven by an electric motor through
sprocket wheels to drag along the bottom of the ash trough and capture
the residue, pull it out of the trough, up a chute and into a waiting
bin or truck. These drag link conveyors are heavily constructed of
heat resistant cast steel drag link parts, with corrosion resistant metal
or concrete tanks and chutes for containing and guiding the wet,
abrasive residue. They travel slowly, thus allowing water to drain
back into the tank from residue moving up an inclined chute. The unused
portion of the drag link chain which is returning from the point of
discharge of the residue back to the entrance to the quenching tank
may require as much supporting, guiding and protective structure as the
working section of the chain.
It is common practice to position drag link conveyor paths transversely
across the discharge ends of two or nore rectangular furnaces so that
the residue of both can be carried to a common discharge point for
economy of overall structure and material of the conveyor. Because the
residue removal conveyors are such vital elements of the incineration
system, and because they are big, heavy. and somewhat difficult to
service, they are often built in parallel pairs with a diverting chute
so that each of several furnaces can direct its residue to each of two
residue conveyors, to ensure reliable service.
Another type of conveyor system is a metal mesh travelling belt on
which the residue falls from the stoker, and is spray quenched. Other
systems, using metal apron type conveyors, vibratory conveyors and
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rubber belts for cooled residue are in use, but the metal drag link
type is the most popular. Manual handling of residue has practically
disappeared, except for a few small older incinerators.
A few incinerators have equipment for separation of residue and salvage
of metal, mostly tin cans. The separation is usually done in a metal
drum or barrel with holes in its sides and mounted to rotate about its
horizontal axis. This tumbles the residue and the ash falls through
into a hopper, while the cans finally pass out the end of the drum to
another hopper. Sometimes magnetic separators are used to collect the
steel from the rest of the residue. The cans are usually pressed flat
or shredded to make them into salable scrap. The non-metallic ash is
a dense, inert material, almost like damp earth, and is sometimes sold
for road fill.
The sittings are dust-like bits of ash, often still glowing, that drop
through the grate openings and cover whatever is below. The amount
varies with the type of stoker and the material being burned. Certain
types of plastics that melt, or greases that can run through the grate
openings may accumulate in the underfire air chambers and ignite and burn
unless precautions are taken. Some stokers rely on manual cleanout
through doors provided for the purpose. Others provide hoppers under
the grates and means ranging from mechanical and pneumatic conveyors to
water sluicing to move the accumulated sittings either to an outside
collection point or into the quenching tank with the other solid residue.
An innovation to combine sittings removal with stoker residue removal
consists of a "wet bottom" furnace in which the entire furnace foundation
is made as a concrete basin which is filled with water. A drag link
conveyor as wide as the furnace runs the entire length of the furnace
and drags out the grate sittings which have fallen into the water, as well
as the stoker residue which falls into the quench water at one end of
the foundation.
Fly ash, in a municipal incinerator, is the particulate matter which
is light enough to be carried out of the furnace by the existing gas
stream. Dust, ash, fine burning particles, and even sizable pieces of
burnt or burning paper are released from the grate by underfire air and
fuel bed agitation, so that about 2 percent of the weight of mixed
refuse charged into the furnace leaves the furnace as airborne fly ash.
The various air pollution control devices, to be described in another
section, collect from 30 percent to 95 percent of this fly ash, either
by dry collection in hoppers or by capturing it in water. As in the
case of sittings, the dry fly ash is conveyed by mechanical or
pneumatic conveyors, or by sluicing with intermittent floods of water
through pipes, either to a storage hopper for truck loading, or to the
residue quenching tank for removal with the other solid residue.
Fly ash entrained in water has been most successfully collected by the
use of settling tanks or lagoons. In either case, a large quiescent
body of water permits practically all of the particulate matter to
settle to the bottom in time, and the relatively clear water is drawn
off the top for re-use, while the particulates are discharged or dredged
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from the bottom. There have been several attempts to separate the
particulates from scrubbing water with centrifuges> mechanical screens
and filters, but there has been little sustained success.
j. CLEANING AND DISCHARGING EFFLUENT GASES AND LIQUIDS
The gaseous products of combustion, in modern municipal incinerators,
usually contain fly ash which is gas borne particulate matter, mostly
incombustible, as well as air, carbon dioxide, water vapor, small
amounts of sulfur oxides, and traces of other gases. The water vapor
and carbon dioxide are natural and acceptable constituents of the
atmosphere, but the other materials, the large particles, the dust and
any noxious, odorous or corrosive gases tend to pollute the atmosphere
and must be controlled within acceptable limits, if they cannot be
eliminated.
The smoke, generally carbon particles less than one micron (.00004
inches) in size, and the odors, generally chemical compounds formed
during the process of combustion, should not exist if there are the time,
temperature and mixture with oxygen for complete combustion. Unfor-
tunately, practically complete combustion is seldom achieved in the
older incinerator designs, and even in the newer ones there are
transient periods of start-up and shut-down, or unusually wet loads or
unusual materials like tires or roofing that can cause smoke.
The particulate matter is collected in three classes of equipment in
existing municipal incinerators: subsidence chambers, mechanical
cyclones, and wet scrubbers, and these are listed in the order of
increasing effectiveness. The "efficiency" of dust collectors is
usually simply defined as the percentage (by weight) of the particulate
matter entering that is caught. For example, if one pound of dust
goes in, and 0.1 pounds comes out in the "clean" gas, then 0.9 pounds
was caught and the efficiency is 0.9/1.0 or 90 percent. This is an
unfortunate method of rating because it makes no allowance for the
variability of size, shape and weight of the gas borne particulate
matter. To illustrate, if the incoming gas stream contained a brick,
several scraps of paper, and a thousand grains of sand, and if the
collector removed only the brick, it would be rated as 99+ percent
efficient by this method. Therefore, the effectiveness (efficiency) of
particulate collectors is meaningless unless all collectors are
evaluated on "standard" fly ash of known density and size analysis.
Such tests are tedious and expensive, and until recently, were seldom
run on incinerators. Instead, the acceptability of incinerator chimney
effluents was often specified and is still often judged on the basis of
a Ringlemann test. This is a visual comparison of the color and opacity
of the "smoke" from a stack, with various samples of grey color on a
printed card, and does not differentiate between carbon fumes, fine dust,
large flakes of paper ash, or visible steam from condensed water vapor,
nor does it allow for different colored sky backgrounds, atmospheric
conditions, or the observer's color perception.
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Subsidence chambers, which are also called expansion chambers, baffle
chambers or settling chambers are in principle large volumes where the
gases are slowed down and retained for a while to allow some of the
particulate matter to settle out to the floor of the chamber by gravity.
Large heavy particles drop out of the gas stream, quite readily,
particularly where there are changes in gas flow direction caused by
baffles. Smaller particles settle out to a degree, if the gas is not
very turbulent and ample time is allowed. However, for typical
incinerator fly ash, with a high percentage of particles below 50
microns (1/500 of an inch) in size, the turbulence of the flowing gas
stream holds most of them in suspension until they pass out the stack.
Since more than half of the total particulate matter in the typical
municipal incinerator fly ash as it comes from the furnace is under 30
micron size, it is understandable that even a large subsidence chamber,
which may be larger than the incinerator furnace, cannot offer very high
collection efficiency. Nevertheless, this is the type of dust collection
system in use in the majority of present municipal incinerators.
An improvement in collection efficiency of subsidence chambers is
obtained by the use of wet bottoms or wet baffles, which, as previously
described, serve to cool the hot flue gases by evaporation, while
trapping and retaining the dust particles that impinge on the wet
surfaces. An obvious extension of the water cooling and impingement
principles is the introduction of water in sprays or cascading curtains
in the ducting and subsidence chambers. However, this rudimentary wet
scrubbing does not statistically bring most of the dust particles into
contact with water droplets or water surface and there is only moderate
improvement in collection efficiency. About 25 percent of the municipal
incinerators have water augmented subsidence chambers.
Subsidence chambers,- with or without water augmentation, are constructed
to have low pressure drops for the large volumes of gas flowing through
them, and consequently they are suitable for natural draft installation
where the motive force for gas flow is provided by the rising hot gases
in a tall chimney, instead of by use of a fan.
Chimneys (stacks) for municipal incinerators are usually constructed
of masonry, though steel or reinforced concrete are becoming more
popular. Tall stacks, often 100 to 250 feet high, are the usual "trade-
mark" of municipal incinerators, towering over everything but power
plant stacks, and often discharging clearly visible plumes of smoke and
steam which have given incinerators a poor reputation as air polluters.
Chimneys are highly specialized and costly structures, since they must
be designed to withstand adverse terrestrial and atmospheric conditions,
to permit access for inspection and maintenance and must be lined with
heat, moisture and acid resistant materials to withstand the attack of
flue gases. Tall stacks allow the discharged particulates and gases to
be caught in upper air currents and dispersed, instead of settling in
the immediate vicinity of the incinerator. Though more expensive in
original cost than an induced draft fan installation, they do not require
continuous use of power. These two features, dispersion and low operating
cost, have probably led to the popularity of natural draft installations
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and thus have limited air pollution control devices to those that could
operate with approximately one inch of water pressure drop.
Chimneys also are natural settling chambers. The flue gas usually
enters through a horizontal duct (breeching) several feet above the base,
and the expansion and turning of the gas as it starts to rise allows
particulates to fall to the base of the stack where they can be removed
through clean-out doors. Sometimes a wet base is provided in the
chimney to trap particulates in water and flush them out hydraulically-
Mechanical cyclones direct the particle-carrying gas at high velocity,
into cylindrical chambers which cause the gas stream to whirl around in
a circular path. The heavier particles are thrown to the outside of
the circle by centrifugal force and are collected in hoppers at the
base of the cylinders while the cleaned gas spins out through the
center of the chambers. The cyclones are usually made of steel and cast
iron selected for corrosion and abrasion resistance. Occasionally,
they are lined with wear-resistant refractory materials in critical
sections. The smaller the diameter of the individual cyclone cylinders,
the higher the centrifugal force that can be developed for a given
pressure drop, but as the cylinders get much below 10 or 12 inches in
diameter, the number required, the supporting and gas-guiding structure,
and the number of small openings prone to plugging, all increase and so
do the cost and maintenance problems. Cyclones are used with 3 to 6
inches of water pressure drop.
Well designed and properly installed cyclone systems can provide
significant efficiency improvements over subsidence chambers, but it is
only in the past ten years that cyclones have begun to find use in
municipal incinerators. At present, fewer than ten percent of incinerators
have them.
Wet scrubbers are the natural outgrowth of wet bottoms and wet baffles,
in the evolution of gas cleaning systems for municipal incinerators.
The principle of wet scrubbing, which is well known in the chemical
processing field, is to bring all the gas into intimate contact with a
liquid which can seize and hold the particulates and gases to be removed
from the incoming gas stream. The liquid must then be separated from
the clean gas. It should be recognized that this results in a stream
of polluted liquid, but there are acceptable methods for processing
liquids to remove the impurities and allow re-use of the liquids.
Almost any degree of gas particulate cleaning desired can be obtained in
a properly designed wet scrubber, providing sufficient mixing energy is
supplied to cause the particles to contact liquid. The energy is
usually applied to breaking the liquid into droplets in various kinds of
spray nozzles, or by moving the gas at high velocity through water, and
in both cases turbulating the gas - water mixture long enough to
statistically assure contact. Removal of the water droplets takes
additional power and is done by centrifugal means (like a mechanical
cyclone) or by flowing the gas through a zig - zag path between baffles
which trap the droplets. For municipal incinerators, five to twelve
inches of water pressure drop is usually used in the gas stream.
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Wet scrubbers provide favorable conditions for dissolving gases containing
sulfur, chlorine and other trace chemicals out of the flue gas stream.
However, these tend to form active acids, when in water solution, and
the scrubbers, ducting, fans and stacks must be constructed of materials
that can withstand acid corrosion.
It is only in the past few years that true wet scrubbing systems, as
differentiated from crude spray chambers or wet baffles, have been
applied to municipal incinerators, and fewer than ten percent of the
incinerators have them. They are usually rectangular chambers, con-
structed of stainless steel or lined with rubber, or cement. Various
configurations of fine sprays, or bubbling the gas upward through layers
of water held on perforated trays or on a bed of spheres are the methods
commonly used to obtain intimate gas - liquid contact.
There have been a few attempts to combine a cyclone and a scrubber into
a wet wall or wet bottomed cyclone. The results have not been satisfactory
for incinerator fly ash because dampened fly ash tends to cake into a
mud and bridges over openings and blocks them. It has been necessary
to keep scrubber surfaces flooded with liquid to prevent "mud" build-up.
The spent liquid coming from wet bottoms, wet baffles, residue quench
tanks, pit drainage, spray chambers and scrubbers in many cases presents
a disposal problem because it is chemically and physically contaminated,
and a water salvage problem because of the cost of water. Where water
supply is no problem, and where sewers or streams are unrestricted, the
older and smaller incinerators sometimes dispose of the waste water
directly without any treatment.
The most common method of water treatment, though used in less than
50 percent of municipal incinerators, is the use of settling tanks or
lagoons. Particulate matter can be collected from the bottom of the
tank or lagoon, and relatively clear water can be drawn off through a
weir at the top. A few of the more recently built plants have installed
mechanical screen strainers, filters, or centrifuges to clarify the
water for recirculation, but the results have been less than
satisfactory.
The waste water which has been in direct contact with flue gases tends
to become acidic, while the water which has leached through fly ash or
siftings may be quite basic. Some of the larger metropolitan incinerators
treat the waste water with neutralizing chemicals before clarification
treatment.
In general, reclamation and reuse of waste water, though desirable, is
troublesome in today's municipal incinerators. Corrosion, abrasion and
plugging of plumbing, pumps, valves and spray nozzles are common problems
unless careful attention has been paid to designing for reuse of
contaminated water.
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CONTROLLING THE PROCESS FOR SAFETY. EFFICIENCY, ECONOMY AND COMMUNITY
ACCEPTANCE
A modern municipal refuse incinerator operating at rated conditions
releases an awesome amount of energy under conditions that could be
destructive to the plant itself and dangerous or offensive to the
community if not properly controlled. Moreover, like any other chemical
process, the quantities and mixture of the reactants (refuse, air and
water) and the conditions of the reaction (time, temperature, turbulence)
must be controlled for satisfactory results. Also, the presence of
potentially hazardous elements like high temperatures, deep pits,
moving conveyors, heavy trucks and cranes and lethal fumes make it
imperative that there be controls to safeguard the operating personnel.
The words "instrumentation" and "control" are often linked together as
a common term, but they are really quite different and the difference
is important. Instrumentation is the equipment used to indicate and/or
record physical conditions like weight, temperature, position, flow,
time, speed, voltage, etc. Instruments give signals, but in themselves
they do not change the conditions of operation. Controls are mechanisms
which change conditions of operation, like a valve which can change
water flow, a switch which can turn on a fan motor, or a speed-up in the
rate of refuse feed which can increase furnace temperatures.
A control "system" must have four basic elements: a standard of desired
performance, a sensor (instrument) to determine actual performance, an
intelligence to compare actual versus desired performance (error) and
to make a correction, and a control device to cause a corrective change
to occur. If these elements are integrated into an automatic system
that controls the process to a set standard, like a household thermostat
that holds 70°F temperature, it is a closed loop or automatic feedback
control system. If, on the other hand, control is effected by making
a change and then observing the result (like steering a car), it is an
open loop system.
Present municipal incinerators generally utilize their instrumentation
in conjunction with open loop control systems, although there are
increasing instances of fully automatic closed loop control systems for
controlling furnace temperatures and furnace draft.
There are many types of instrumentation used in incinerators, but they
can be classed as follows:
1. Temperatures
- Optical pyrometers for flame temperatures in the range of 2,200°F
to 2,500°F.
- Thermocouples (Chromel-Alumel) for furnace temperatures in the
1,400 to 1,800°F range and iron-constantan in duct temperatures
down to 100°F.
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- Gas or liquid filled bulb thermometers for duct temperatures,
below 1,000°F. and for ambient temperatures and water temperatures.
2. Draft Pressures
- Usually only a few inches of water column.
- 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 1 to 100 psi
- Bourdon tube pressure gauges for direct readout.
- Diaphragm actuated sensors for remote readout.
4. Gas Flows
- Orifices or Venturis with differential pressures measured by
draft gauges.
- Pitot tubes and draft gauges.
5. Liquid Flows
- Orifices with differential pressure measurement.
- Propeller type dynamic flowmeters.
6. Electrical Characteristics
- Voltmeters, ammeters and wattmeters.
7. Smoke Density
- Photo-electric 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 cameras for closed circuit television for viewing furnace
interiors, furnace loading operations or stack effluents.
- Peep holes in furnace doors.
- Mirror systems.
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The general functions of control systems in present day municipal
incinerators are:
1. To control underfire airflow despite varying furnace draft and
varying restrictions to airflow through the grate openings.
2. To control overfire air as a means of controlling furnace temperature
as the quantity and heating value of the charged refuse vary.
3. To control furnace pressure by varying the draft induced by the
chimney or the I.D. fan.
4. To control gas temperature at the dust collectors by varying the
amount of quenching water or diluting air introduced.
5. To control refuse drying and burning time by varying the conveying
speed of the stoker mechanism.
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. Often, a duplicate panel of indicating instru-
ments is placed in the plant superintendent's office for additional
surveillance.
It is quite common to have recording type instruments which indicate on
a removable paper chart, the conditions which exist over a 24 hour period.
These records can be very useful in making statistical summaries of
operating conditions, and of reviewing operating conditions which may
correlate with a malfunction.
L. PROTECTING THE PERSONNEL AND EQUIPMENT
A modern municipal incinerator plant represents an investment of two
million dollars or more in equipment and structure, and is expected to
serve the community for about 25 years with reasonable maintenance.
However, there are forces continuously at work tending to deteriorate
the incinerator, namely, the environment, dangerous refuse and careless
operation. The experience of engineers and operators has resulted in
design features and operation procedures which serve to protect incin-
erators.
At the receiving bays and storage pits, clearly marked traffic lanes,
high intensity lighting and heavy duty curbings and rails reduce the
incidence of collisions between refuse trucks and the columns and
structures of the receiving area.
Lining the concrete storage pits with steel bumping rails and attaching
heavy wear-shoes to the crane bucket can greatly reduce mutual
deterioration of pits and crane buckets of grapples. Enclosing the crane
machinery and subduing the dust of the storage bins with ventilation
and water sprays is a means to reduce crane "down time" and improve crane
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life. Adequate clearance room and automatic stops save damage from
crane overtravels.
Storage pits are susceptible to fires from spontaneous combustion or
from smoldering refuse inadvertently dumped in. Sprinkler systems or
at least ready water hoses are employed in most incinerators.
Backfires in the loading hoppers of continuous feed incinerators may
occur, particularly if the furnace pressure rises above atmospheric.
Many incinerators provide metal covers or cut-off dampers on the loading
hoppers or chutes so that backfires can be quickly contained and
smothered.
Undergrate or windbox fires can be a source of damage if a slow burning
meltable or powdered fuel, usually special industrial waste, is fed in
large quantities. The combustible refuse may fall through large grate
openings and the resultant fire from below may burn or warp stoker
parts. Good grate designs and reasonable surveillance of incoming
refuse are the measures usually employed to prevent this.
Overheating of the furnace chambers or hot gas ducting can cause serious
damage in a short time. Multiple temperature sensors, closed loop
control systems, and audible and visual alarm systems are employed to
avoid this danger. Increasing overfire air, reducing underfire air and
reducing refuse feed rate are control methods used to reduce furnace
temperature.
Failure of the quench water supply, whether from clogged nozzles, pump
failure, electrical power failure or lack of water, can be quickly
disastrous to the flue gas cleaning system and fans. Auxiliary water
towers and automatic bypass ducting that can dump the furnace gas
directly to the stack are the usual provisions for such an emergency.
Loss of electrical power can be anything from an annoyance to a disaster,
depending on the particular system involved. Several incinerators have
standby auxiliary power supplies with gasoline, diesel or turbine engines,
In cold climates freezing water can do damage to piping and to wet
conveyor systems. The common practice is to enclose such sensitive
systems in heated buildings, or to selectively heat sensitive lines.
Corrosion is the perpetual enemy of the metal structures and equipment
of incinerators, particularly when even traces of sulfur, nitrogen and
chlorine in flue gases can acidify moisture. Enclosing mechanisms in
weather-proof shelters, good painting practice, use of corrosion
resistant metals and stainless steel, and use of durable non-metallics
where warranted, are the protective methods employed.
Much concern has been expressed over the danger of municipal incinerator
explosions, but there appear to be no records of serious damage resulting
from explosions of pressure cans, paints and solvents, chemicals, and
even ammunition and dynamite. One reason for this seems to be that the
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furnace volumes are large and unconfined, so that even a. sizable
explosion cannot make much of a pressure wave, Furnaces are usually
lined with thick layers of brick and are steel cased, and there is
usually a "cushion" of several inches of porous slag on the inside
surfaces. Also, many of the potentially explosive containers soften
or burn before an explosive release of energy can occur.
Personnel safety and reasonably tolerable, if not attractive, working
conditions are necessary to recruit and retain people competent to
operate a modern incinerator efficiently. Guard rails around pits,
hoppers and conveyors, good lighting, good ventilation, protective
clothing and eye shields for working at furnace openings, and constructive
safety training programs are to be found in the majority of installations.
Also, well managed municipal refuse disposal plants are essentially
odor free, clean and dry, with well appointed locker rooms, lunch rooms,
reception lobbys and administrative offices. The buildings generally
have pleasing and functional architectural treatment with fences and
landscraping designed to make them good neighbors.
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SECTION IV
FUTURE DEVELOPMENT IN MUNICIPAL INCINERATORS
In the period of 1961 to 1967, there has been a remarkable Increase in the
rate of evolutionary development of the art and science of municipal refuse
incineration in the United States. During the 1950's, there was growing
awareness that the expanding population, the increasing combustible refuse
per capita, the diminishing availability of disposal land, and the dependable
performance of well constructed continuous flow incinerators in cities like
New York, Philadelphia, Atlanta and Chicago were pointing to incineration
as a major factor in municipal refuse disposal plans for the latter half of
the 20th century.
In 1961, the American Public Works Association published the first edition
of "Municipal Refuse Dispsal" with a full chapter describing the engineering
principles and practices of central incineration. In 1964, the first
National Incineration Conference was sponsored by the American Society of
Mechanical Engineers, and the published "proceedings" containing the twenty-
nine technical papers of the conference became, in effect, the first
American textbook on incineration design. In 1965, the International
Research Group on Refuse Disposal Conference in Trento, Italy brought to the
attention of American refuse disposal authorities the technical advances in
municipal incinerators that had been made in Europe. In May, 1966, the
Second ASME National Incinerator Conference was held and its thirty-four
technical papers became part of a now sizable bibliography on the subject of
incineration.
On October 20, 1965, the Solid Waste Disposal Act, " to authorize a
research and development program with respect to solid waste disposal......"
became Public Law 89-272 and provided the impetus for bringing the resources
of universities, research organizations, governmental bodies and industry to
bear on the problems of solid waste disposal. Naturally, part of this effort
is being devoted to methods of improving existing incineration equipment and
performance, and toward developing ideal municipal incineration systems for
the future.
A review of recently completed incinerators and specifications for others
to be built, and interviews with leading consulting engineers and incinerator
buying influences have revealed the following probable patterns of develop-
ment and improvement.
A, RECEIVING, MEASURING AND STORING
It is expected that the principal changes in these areas will be those
reflecting the ever larger quantities of refuse to be handled. Following
the European developments, it is reasonable to suppose that refuse will
be brought to central incinerators by larger trucks, by rail and by barge
and there will be need for better methods of rapid unloading and nuisance-
free storage. The bridge crane with faster travels and simplified
controls will probably be supplemented by various types of conveyors,
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including pneumatic transportation systems. The storage pits will
continue in vogue for the larger plants, but the smaller towns may go
increasingly toward open floor dumping because of lower first cost. In
both cases, there is likely to be better enclosure of the stored refuse,
sprinklers for dust and fire control and mechanical ventilation for
discharging the odorous exhaust air into the incinerator.
B. SORTING, MIXING, FEEDING
Considerable effort is being expended to improve these functions, and
it is therefore likely that future municipal incinerators will include
new equipment for preparing the refuse for efficient incineration.
Breakers, crushers and shredders will be employed to reduce awkward
size combustibles like wooden pallets, demolition lumber and furniture
to smaller pieces, and obviously incombustible items like bathtubs,
bicycle frames and kitchen stoves will be separated during the collection
process. There are signs of growing interest in special bulky refuse
incinerators for logs, brush and furniture.
It is not expected that there will be a significant trend toward pre-
incineration salvage. Fairly sophisticated machinery has already been
developed for this purpose for composting operations, but the salvaged
materials, even when classified, are troublesome to market. "Tin cans"
contain steel, tin, solder, plastics, aluminum, paper and residual food,
and are not desirable as scrap. Clothes are often unsalvagable mixtures
of synthetics and natural fibres, and the market for salvaged glass and
even clean paper is undependable.
There is likely to be increasing interest in various types of ram and
conveyor feeders as supplements to the gravity fed hopper and chute. The
use of wheeled vehicles to load furnaces from floor dump operations is
also expected to increase. As shredding and grinding of refuse become
more common, more mechanical or pneumatic conveying of the prepared fuel
into the furnace will probably be employed.
C. FURNACES
It appears that developments in municipal incinerator furnaces will
proceed in several directions; refractory lined furnaces and water wall
furnaces, both with conventional flow-thru stoker systems, and a number
of advanced concepts. Some of these may prove to be impractical, but
others may, in time, offer significant advantages.
There is a trend toward air cooled walls in refractory lined furnaces,
and the use of silicon carbide or high alumina facings in the slagging
and abrasion zones of the furnaces. Air cooling is accomplished by
natural or forced circulation of air over the outside of the refractory
lining, and often the air which has picked up heat from the lining, is
discharged into the furnace as overfire air. The cooled walls seem to
resist penetration by heavy glassy slags, so that the slag falls off or
is easily removed, without causing spalling (breaking off layers) of the
refractory surface. There is increasing recognition that with the high
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heating value of American refuse, it is not as necessary to heavily
insulate the furnace walls to conserve all the heat of combustion. With
thinner, more conductive air cooled walls, some excess heat can be
directly dissipated through the furnace walls to reduce furnace
temperatures and improve refractory life.
There is also likely to be increasing use of plastic and castable
refractories for walls and arches (ceilings) to reduce the labor involved
in the traditional methods of laying up firebrick.
Waterwall furnaces are expected to find increasing use, both as cooling
surfaces to shrink gas volume so the flue gases can be more easily
cleaned, and as heat absorption surface in steam generation systems.
Following European incinerator practice, there may be refractory coated
tubing used for corrosion resistance in critical areas of the furnace.
The stoking systems and grates used in these furnaces will probably
undergo detail improvements to increase ease of servicing and durability.
The new designs will tend toward controlled agitation of the residue to
strike the best balance between full combustion and least generation of
fly ash.
Some of the more novel approaches to incineration of municipal refuse
under experimentation are suspension burning, melting with auxiliary fuel,
pyrolysis, fluid bed combustion and pressurized burning. Suspension
burning, which is the process widely used in power boilers, consists of
blowing the finely divided fuel into a vortex pattern in a furnace chamber
so that it burns while suspended in the turbulent air stream. It is
efficient and can provide high heat release in a relatively small volume,
without the necessity for supporting a--burning fuel bed or a grate or
hearth. Well controlled preparation of the refuse is required.
Melting of the incombustible residue can be accomplished if the heat
release of the burning refuse is augmented by burning it with a high
quality fuel like coke in a properly designed refractory chamber. The
melted residue, including metals and minerals, can be run into a water
bath where it solidifies and fractures into coarse crystals which are
probably the ultimate in cleanliness, compactness and desirability as a
residue.
Pyrolysis consists of decomposing the refuse by the application of high
heat, without supplying oxygen for combustion. Theoretically, the refuse
can be converted to combustible gases, fixed carbon (like charcoal)
liquids and tars containing useful organic chemicals and inert ash,
metals and minerals.
Fluid bed combustion is carried out in a bed of inert granular mineral
(like sand) which is heated in a refractory vessel on a perforated plate.
Air is blown upward through the holes in the plate at a controlled rate
which churns the sand into a turbulent mass like quicksand. After
preheating with a gas or oil burner, the refuse is introduced and burns
while circulating in the hot sand. Theoretically, there is excellent
control and complete combustion. Separation of the residue from the bed
material presents a problem.
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Pressurized burning may be performed by any of the above methods, in a
smaller furnace than normal, by introducing the combustion air under
high pressure. The same weight of air is thus contained in a smaller
space, so combustion can proceed normally. The additional power
required to compress the air is a drawback, but the existence of hot
pressurized flue gas offers the thermodynamic possibility of directly
operating a gas turbine engine to generate useful power.
D. DISSIPATION OF THE HEAT OF COMBUSTION
A fair amount of interest is being shown in the use of gas-to-air heat
exchangers of tubular construction to cool and shrink the flue gases
without the corrosion, mud-forming and waste water disposal problems
of wet quenching. The heated ambient air can be directly released to
the atmosphere without pollution problems, but the tubes must be designed
so that they are not blocked or corroded by the raw flue gas emerging
from the furnace.
If the heat absorbed in water walls is merely to be dissipated, it is
likely that air-cooled condensers will be preferred, because they do
not produce a cloud of visible steam in cold weather like cooling
towers do, and they do not require large supplies of cooling water as
water cooled condensers do.
Perhaps the most sensible prospect, and therefore the concept that may
ultimately prevail, is to convert the incinerator furnace waste heat
into steam which can be used for one or more of the following purposes.
1. For heat and power required in the operation of the incinerator
plant itself.
2. For heat, power and process steam exported to nearby industry,
institutions or municipal installations.
3. For power to be fed into commercial electric utility networks.
E. HANDLING OF RESIDUAL SOLIDS
As the burning process developed, there has been improvement in the
"quality" of the residual materials, but the ever-increasing quantities
of residue and the form of it dust, sludge and miscellaneous
incombustibles make it likely that continued attention will be paid
to application of modern materials handling techniques.
Hand cleanout of sittings will almost certainly disappear in favor of
automatic sittings collection by mechanical, pneumatic, or sluice-type
conveyors. Hot collection of stoker residue with quenching by water
spray in a hopper will probably be replaced entirely by direct quenching
of the residue in water filled sumps. The all metal drag-link conveyor,
while presently the most popular residue handling system, is likely to
see competition from the less costly European type systems of swinging
metal pushers to lift the cooled residue from the quench tank, followed
by rubber belts or metal plate type belts to transport it to the disposal
point.
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It is also probable that there will be continued efforts to separate
metal cans and bulky items from the dust, sludge and minerals of the
residue, not only for the possible salvage of the metal (burned out tin
cans have certain value as scrap and for metallurgical processing), but
to make the non-metallic residue more valuable as high quality fill. As
an alternative, the cans and clinkers may be crushed or ground to reduce
the volume and improve the homogeneity of the total residue.
AIR POLLUTION CONTROL
It is the consensus of the industry that improvements in air pollution
control systems and equipment will be the most immediate significant
change in the next generation of municipal refuse incinerators. Although
municipal incinerators contribute only a few percent to the total air
pollution of a metropolis, the clearly visible tall chimneys with their
plumes of smoke, or even white steam, the lingering mental association
between incinerators and smoky; odorous burning open dumps, the
occasional fallout of dust and flakes of charred paper from old systems
with little air pollution control equipment have made the public
conscious of municipal incinerators as pollution makers rather than
pollution controllers. The methods and equipment for air pollution as
control to almost any degree desired are commercially available. The
problem has been a lack of enforced air pollution control standards, and
the desire to "economize" in the purchase and construction of central
incinerators.
Engineering studies have indicated that in order to comply with the more
stringent air pollution codes now in existence or being prepared, a
modern municipal incinerator might require 94 percent overall collection
efficiency with a fractional efficiency of about 75 percent by weight
collected of all particles sized five microns and below.
These efficiencies can be obtained with high quality mechanical cyclones,
wet scrubbers and filter bag collectors with a fan-powered induced draft
system. With natural draft alone, they can only be achieved with
electrostatic precipitators. Odors and true smokes of submicronic
particles can be virtually eliminated by proper combustion control in
the furnace, although bag filters and electrostatic precipitators can
collect smoke particles, and wet scrubbers can dissolve out certain
odorous or noxious gases.
It is expected that there will be a strong movement toward electrostatic
precipitators and high performance wet scrubbers. The electrostatic
precipitators operate on the principle of electrostatically charging the
particles in a gas stream by passing them through the corona of a high
voltage (upward of 40,000 volts) conductor. The charged particles are
carried at very low velocity between oppositely charged electrical plates
where they are attracted out of the gas stream and cling to the plates.
At intervals, the plates are shaken and the accumulated dust falls into
hoppers. Electrostatic precipitators are large and relatively expensive
because they must handle large volumes of gas at low velocity. They can
have difficulties if the particulates will not accept and hold the
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electrical charge because of high temperature or chemical composition.
If the fats and greases of refuse have not been properly burned in the
furnace, they can condense in the precipitator and cause malfunction and
fire. Also, large flakes of burned paper can sail right through them
if not otherwise trapped and collected. Nevertheless, they have been
used quite successfully on European incinerators and will be used on
American incinerators, both for upgrading existing installations and
for new installations. Waterwall furnaces or waste heat boilers,
which cool and reduce the volume of the flue gases will permit use of
smaller and less costly electrostatic precipitators.
Wet scrubbers and also water quenchers, tend to saturate the hot flue
gases with water vapor. As the flue gases emerge from the stack and
encounter cold air, some of the water vapor condenses into visible
steam. The public tends to confuse this harmless steam with smoke, so
it is expected that future scrubbers will be equipped with heat
exchangers to reheat the scrubbed flue gases using furnace heat, to
reduce the incidence of visible steam plumes. If the scrubbing water
is kept cold, the flue gases will be cooler and less moisture will be
picked up in the scrubber. For this, settling ponds with spray coolers
and ordinary cooling towers may be called upon to cool the recirculating
water.
Mechanical cyclones should also appear in upgraded existing incinerators
and in some new ones. Unfortunately, there has been some poor experience
with improperly designed equipment, inadequate draft, and carried-over
quench water and it will be difficult to convince the buying influences
that these problems can be overcome through competent engineering.
Bag filters suck the flue gases through the woven fabric walls of
special bags, like vacuum cleaner bags. A pre-coat of dust forms and
thereafter catches just about all the solid matter entrained in the gas
stream. The multiplicity of bags are contained in a large structure
(baghouse) and equipped with automatic devices to divert the gas stream
and shake the collected dust off the bags and into hoppers at appropriate
intervals. Bag filter installations can do a near perfect job of dust
collection, but they are expensive, and require considerable power and
maintenance. It is believed that other methods of air pollution control
will be accepted more readily on future incinerators.
It is also likely that there will be increased use of induced draft fans
specially designed for municipal incinerator use. These will be of
heavy duty, abrasion resistant and corrosion resistant construction for
reliability; and will include flow control by variable speed or by
efficient damper systems. Because the induced draft fans on large
incinerators may require 100 or more horsepower, more attention will be
given to fan efficiency and durability, rather than to lowest first cost.
CONTROLS AND INSTRUMENTATION
Industrial process instrumentation and controls are a highly developed
art and future incinerators may be instrumented and atuomated to almost
any desired degree. However, it is expected that municipal incinerators
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will not go very far toward fully automated or computer-controlled
operation in the next few years because municipalities will continue to
look toward their refuse disposal operations as sources of employment for
many unskilled and semi-skilled people. Also, the fact that these
people will be engaged in the operation of incineration systems will
lead to the adoption of automatic controls for certain critical
parameters like furnace temperature and percent of carbon dioxide in the
flue gas; and very simple, perhaps color coded, "on ^ off" type signals
and push buttons for the less critical functions. Read-out instruments
giving the precise numerical value of each temperature and pressure
in the system may not be considered worth their cost.
H. PROTECTION OF EQUIPMENT AND PERSONNEL
As the sophistication and cost of municipal refuse incineration system.
equipment increases, it is logical to suppose that continued attention
will be paid to protection of the capital investment. For reasons of
economy and efficiency, however, it may be that municipal incinerator
structures will have less future emphasis on traditional architecture
(like a town hall or a school) and tend more toward weather resistant
unenclosed furnaces and ducting, and minimum functional enclosure of
offices, workshops and critical equipment.
In keeping with the generally increasing social consciousness, it is
expected that there will be additional safety provisions, training,
comfortable work stations and uniformed technicians and skilled managers
whose service to the community can be rendered with dignity and profes-
sional satisfaction.
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SECTION V
REFERENCES
1. Municipal Refuse Disposal. Book prepared by American Public Works
Administration, Public Administration Service, Second Edition,
Library of Congress, No. 66-25574.
2. Proceedings of MECAR Symposium. Incineration of Solid Wastes.
New York, New York, March 21, 1967. Library of Congress,
No. 67-25957.
3. Proceedings of 1964 National Incinerator Conference, New York,
New York, May 18 - 20, 1964. Published by American Society of
Mechanical Engineers. Library of Congress, No. 64-21647.
4. Proceedings of 1966 National Incinerator Conference, New York,
New York, May 1-4, 1966. Published by American Society of
Mechanical Engineers. Library of Congress No. 64-21647.
5. Treatment and Disposal of Refuse and Sewage Sludge. Papers presented
at Third International Congress, International Group on Refuse
Disposal (IRGRD)5 Trento, Italy, May 24 - 29, 1965.
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PART 5
INCINERATOR AIR POLLUTION CONTROL EQUIPMENT
Dr. J. H. Fernandes
Senior Project Engineer
Product Diversification Department
November 1, 1967
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TABLE OF CONTENTS
Page
I. SUMMARY AND CONCLUSIONS 1
II. INTRODUCTION 2
III. SYSTEM EQUIPMENT CONSIDERATIONS 3
IV. INCINERATOR PARTICULATE EMISSION 5
V. EMISSION STANDARDS 7
VI. INCINERATOR AIR POLLUTION CONTROL EQUIPMENT 10
VII. INCINERATOR AIR POLLUTION CONTROL EQUIPMENT PERFORMANCE .... 17
VIII. COST OF AIR POLLUTION CONTROL EQUIPMENT FOR INCINERATORS ... 22
IX. INCINERATOR ODOR AND GASEOUS EFFLUENTS 29
X. TALL STACKS AND DISPERSION 30
XI. REFERENCES '. 32
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SECTION I
SUMMARY AND CONCLUSIONS
This report presents the performance capability of the major classes of
air pollution control equipment. More knowledge of incinerator pollutants
is required, and some application research must be conducted if this
equipment is to be applied to incinerators with optimum results. Air
pollution control equipment if properly designed, installed and maintained
can meet stringent air pollution regulations.
Of first importance to incinerator air pollution control is proper combustion
within the burning system. Under these conditions, high efficiency mechanical
collectors, wet scrubbers, electrostatic precipitators, and fabric collectors
can meet present and projected incinerator air pollution control regulations.
However, conventional wet and dry settling chambers will usually not be
satisfactory.
The relative capital and operating costs, water requirements and pressure
drops for different air pollution control systems are also presented
together with design charts for system selection. It is concluded that
technology is not the limiting factor in controlling air pollution; rather
it is the communities' willingness to finance the additional cost for
sophisticated air pollution control equipment. It is estimated that
present and projected emission levels can usually be obtained for a cost
not exceeding 15 percent of the total plant cost.
Finally, it is concluded that visual observations are not an accurate
means to determine incinerator stack emissions. Measurement of the pollution
control capability of the burning system by sampling of the flue gas is
recommended. Although an incinerator stack may appear reasonably clean
because of the diluting effect caused by the extremely large quantities of
air usually introduced into the burning system, the fly ash load in the gas
may be excessive.
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SECTION II
INTRODUCTION
This section of the report discusses the problem of incinerator air pol-
lution and its control. The problem of refuse disposal is inextricably
involved with the problem of air pollution regardless of the method of
disposal. Incineration offers the opportunity to remove offensive odors
and to reduce the bulk of the refuse to a sterile landfill, but it can be
a significant contributor to the air pollution problem in an urban com-
munity. The primary air pollution concern is with particulate emission
rather than gases or odors; therefore, the emphasis in this section will be
on particulate emission.
There have been comments that a well run incinerator does not need particulate
collection equipment. Many systems with little or no air pollution control
equipment have been represented as effectively meeting dust emission
requirements when they actually do not. This occurs because the excess air
used for combustion and cooling is so great (200% to 500% exces3 air) that
it dilutes the effluent to the extent that it does not appear objectionable,
although excessive quantities of dust are actually emitted. With the trend
toward large efficient incinerators located close to the population centers
served, effective control of incinerator atmospheric pollution is extremely
important.
The degree of gas cleaning to be required and the cost of the primary control
equipment will be discussed in the sections to follow. Relative costs for
various degrees of control will also be presented. It should be understood
that data in this section is based primarily on knowledgeable technical
opinions. The time and effort were not available to completely investigate
all the numerous incinerator parameters affecting the stack effluent. This
portion of the study addresses itself particularly to the large, continuously
fed incinerator common to modern municipal practice.
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SECTION III
SYSTEM EQUIPMENT CONSIDERATIONS
In an incinerator, continuous, rather than batch, feeding of the refuse can
reduce air pollution. Continuous feeding permits greater control over
furnace temperature and therefore influences the completeness of combustion.
Other design and operating factors which insure low fly ash emission from
an incinerator furnace are:
1. Excess air should be maintained between 50 and 150 percent to insure
proper burning and control of furnace conditions.
2. Furnace exit temperature should be held between 1,400°F and 1,800°F to
minimize slagging and to eliminate stack odors.
3. Furnace design must allow sufficient residence time for combustion to
be completed.
4. Overfire air should account for from 20 to 40 percent of the total air
and should be introduced into the furnace in such a manner that it
insures sufficient turbulence for complete combustion.
5. Gas quenching or heat removal should be arranged so that it does not
affect combustion. If water quenching is used, it should be arranged
to remove some of the larger fly ash particles.
With good combustion, the limited amount of fly ash produced is very fine
and is difficult to capture in the collector. It is, however, well within
the capability of present technology to capture most of the particulate
matter.
The advent of polyvinylchloride (PVC) and other plastics that contain a
high percentage of chlorine and/or fluorine (Teflon) may subject incinerator
metals to severe corrosion attack. The problem is particularly acute during
periods of start-up and shutdown when the chlorine and other halogens as
well as sulfur combine with the plentiful moisture in the flue gas to form
highly corrosive acids. During normal operation, the higher temperature
diminishes the danger of formation of the corrosive elements. If water
quenching or gas scrubbing is incorporated into the incineration system,
special metals must be used to handle the corrosive acids formed and the
water must be treated to neutralize the acid attack. Gas quenching is
necessary in U. S. incineration practice, since water walls or other heat
exchangers are not normally used, and since the furnace exit temperature is
usually in excess of 1,500°F, the cost of fans and fly ash collectors which
could withstand these temperatures is prohibitive.
Much peripheral equipment has a direct bearing on the performance of the fly
ash collection equipment. Improper gas ducts leading to the collectors can
upset gas and dust distribution, thereby affecting collector performance.
The collection equipment designer must analyze the flow and incorporate
proper ducting.
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Dust hoppers are secondary collectors or settling chambers as well as dust
storage space. The hoppers must be liberally sized and not allowed to fill
completely if they are to accomplish the final state of gas-dust separation
as intended. Ash removal systems must be properly engineered and automatic
continuous hopper emptying is preferable. Continuous hopper discharge
insures maximum hopper space for dust separation.
All collector performance reported in this part of the report was obtained
from tests made in accordance with methods and procedures established by the
American Society of Mechanical Engineers' Power Test Codes Nos. 21 and 27.
Similarly, all dust sizing data reported has been determined in accordance
with ASME Power Test Code No. 28.
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SECTION IV
INCINERATOR PARTICULATE EMISSION
The quantity and size of particulate emission leaving the furnace of an
incinerator varies widely, depending on such factors as the refuse being
fired, method of feeding, operating procedures and completeness of combustion.
The information presented below includes some results obtained by Combustion
Engineering, Inc., and published data from a number of other sources. This
study has shown the need for more knowledge of incinerator emissions.
The rate of furnace dust emissions has been reported to vary from less than
10 pounds to as much as 60 pounds of dust per ton of refuse burned. High
performance, compact, turbulent incinerators of the type considered here
operate close to the middle of this range, or about 35 pounds per ton. In
practice, dust loadings are reported in various ways. This 35 pounds per
ton may be reported as:
3.5 pounds per million Btu (assuming 5,000 Btu per pound refuse).
2.97 pounds of dust per 1,000 pounds of flue gas adjusted to 50 percent
excess air.
1.58 grains per standard cubic foot adjusted to 50 percent excess air.
These dust loadings refer to conditions "leaving the furnace". It should be
understood that this means leaving the combustion zone, including any
after-burner or secondary furnace, and ahead of the quench chamber.
Dust sizing, like dust loading, varies widely- Most of the same factors
which affect the dust loading of the gas also affect dust sizing. Improved
incinerator performance, which reduces dust quantities, also decreases the
size of the individual particles. The dust is always quite heterogenous,
consisting of rather typical fly ash combined with large, low density flakes.
Dust density has been found to vary from an average of slightly over two
grams/cc (125 lbs./ft.3) to as high as 3 grams/cc (187 lbs./ft.3). The
dust size as determined in the BAHCO centrifugal classifier, using the methods
and procedures of the ASME Performance Test Code No; 28, indicate a size
range distribution as presented in Figure 1. From this figure, it is
evident that on the average about 35 percent of the dust leaving the furnace
is below ten microns (1 micron = 3.94 x 10~^ inches) and represents a
difficult dust to collect. Settling chambers and spray chambers do not
remove sufficient quantities of this dust to meet even lenient air pollution
regulations, and more sophisticated equipment must be used.
-5-
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9Q-
60-
£^ CUMULATIVE PARTICLE SIZE DISTRI BUT I ON-INCINERATOR FLY ASH
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PERCENT BY WEIGHT LESS THAN SIZE
-------
SECTION V
EMISSION STANDARDS
The foregoing discussion has indicated the size and quantity of the dust
generated in a modern, well run incinerator. The question remains as to
how much of this is to be emitted to the atmosphere. Present 'day good
practice controls to 0.85 pounds of fly ash per thousand pounds of flue
gas, adjusted to 50 percent excess air (1 pound per 1Q6 Btu) , as suggested
in the "1949 ASME Example for a Smoke Regulation Ordinance". The ASME
published a new suggested regulation in 1966 entitled "Recommended Guide
for the Control of Dust Emission - Combustion for Indirect Heat Exchangers".
It seems reasonable to assume that this document will receive the widespread
acceptance that the earlier suggested ordinance did. Thus, one should
expect future codes to lower the allowable emission from 1.0 to 0.80 pounds
of fly ash per million Btu or 0.68 pounds of dust per thousand pounds of
gas corrected to 50 percent excess air. This seems a reasonable level for
most installations. The only exceptions might be in the larger more con-
gested metropolitan areas or in an area with adverse topography such as the
Los Angeles basin. Many of these areas may wish to adopt the recent Federal
Facilities Regulations published in the Federal Register, Volume 31, No. 107,
June 3, 1966. These regulations limit emissions to 0.6 pounds of dust per
million Btu fired for incinerator capacities up to approximately 25 tons
per day and a gradual decrease from this level with larger capacities. A
250 ton per day unit would only be allowed 0.4 pounds of fly ash per
million Btu. Figure 2 has been included to illustrate these various control
standards.
Since particulate emissions from large incinerators are of major concern to
the community, there exists a trend to tighten regulations and this is being
spearheaded by certain communities. Among them are the following:
Maximum Allowable Emission
Lbs. of Corrected
Community* Lbs./106 Btu Flue Gas**
New York City 0.77 0.65
Detroit, Michigan 0.35 0.30
Cincinnati, Ohio 0.47 0.40
San Francisco Bay Area 0.44 0.38
* Reference: "A Compilation of Selected Air Pollution Emission Control
Regulations and Ordinances", H.E.W. Report A65-34.
** Corrected to 50 percent excess air.
These codes have the added advantage that they do not relate the allowable
emission to the pounds of refuse burned. This is considered poor practice
because the refuse varies widely in composition and heating value. It is
much more desirable to know the heating value and relate the permissible
-7-
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MAXIMUM ALLOWABLE PARTICULATE EMISSION
FOR COMBUSTION UNITS
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GRAINS/ST.CU.FT. CCORRECTED TO-50% EXCESS AIR)
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-------
emissions to the Btu input. Most codes also include opacity or optical
density of smoke limits. These had considerable value at the turn of the
century when an effort was underway to improve combustion and to reduce the
objectionable unburned effluent. This is no longer the case, and if an
incinerator plume exhibits more than a number one Ringelmann-'- reading,
the plant is probably being improperly operated and this should be corrected.
Dust collecting equipment can not be expected to compensate for faulty
operation.
Opacity regulations should not be used in a quantitative manner because the
measurement is empirical in nature and has definite limitations. The
apparent opacity of a stack plume depends upon:
1. Concentration of particulate matter.
2. Size of particulate matter being transported.
3. Color of particulate matter.
4. Variation in stack outlet velocity.
5. Depth of plume (stack diameter).
6. Natural lighting conditions including intensity and background.
7. Direction of the sun relative to the observer.
8. Amount of excess air employed.
9. Water vapor in the plume.
10. Training of the observer.
In place of the opacity requirements, the following factors should be given
consideration in developing air pollution regulations:
1. A safe emission level for the size of plant and the topography about
the plant should be established.
2. All allowable emissions should be applied to the operational level of
the plant and not to the plant's design point.
3. The maximum size of particle to be emitted should be limited.
4. Regulations should be based on heat input or corrected to standard
conditions.
5. Adjustments for stack height should be allowed.
The projected levels of emission discussed here are all within the capability
of present technology; it is essentially a matter of economics. If the
community is willing to establish and police rigorous standards and to pay
for the necessary gas cleaning equipment, the incinerator can be a good
neighbor.
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SECTION VI
INCINERATOR AIR POLLUTION CONTROL EQUIPMENT
The previous paragraphs made reference to the ability of modern technology
to cope with more stringent air pollution control regulations. Equipment
capable of accomplishing this task will now be discussed. Air pollution
control of incinerators is a unique field with many peculiar problems which
must be solved. Before the various devices and their capabilities are
discussed, it should be noted that equipment performance is significantly
affected by the completeness of combustion, operating procedures and the
adequacy of maintenance. The following presentation assumes a modern,
properly designed, operated and maintained incinerator plant.
The early steps toward the reduction of particulate matter, emitted from an
incinerator stack included the use of a settling chamber or combined settling
chamber-spray coolers. Dry settling chambers on normal incinerator fly ash
approach 20 percent efficiency if they are properly designed and are large
enough to sufficiently reduce the gas velocity. The combined settling
chamber-water spray gas cooler, when correctly designed, can remove 30
percent of the fly ash leaving the furnace. This combination gained popularity
because they offered additional volume to complete combustion. Before the
advent of modern incinerators with their controlled refuse feed and large
furnace volumes, settling chambers gave a needed additional combustion volume
and removed the large unburned flakes, or "blackbirds". Today, the
secondary chamber is smaller or non-existent. It may be much smaller if
its essential purpose is water quenching of the gas to a temperature acceptable
to the air pollution control equipment (APCE) and induced draft fans. The
temperature of gases leaving such spray chambers is usually about 600°F.
If, on the other hand, the gas shrinking and cooling is accomplished by
indirect heat exchange, such as in a boiler or gas to air heat exchanger, no
settling chamber is required. Because the large settling chamber requires
considerable space and is insufficient for the complete gas cleaning task,
it is not expected to be used as frequently in the future.
The mechanical (cyclone) collector is the next step up the ladder of air
pollution control equipment performance and cost. It usually consists of
either of two basic types the multi-cyclone or the large involute cyclone.
The multi-cyclone units are made up of numerous axial inlet (vaned) mechanical
collecting tubes which vary in diameter from 6 to 10 inches and are arranged
in a tube sheet to receive the incoming dirty gas. The inlet spinner vanes
impart a swirl to the gas which creates a strong vortex within the main tube.
This vortex centrifugally separates the dust from the gas stream and allows
the clean gas to proceed up the outlet tube which connects to a second tube
sheet. This sheet separates the inlet dirty gas from the leaving clean gas.
Separated dust moves down to the lower outlet and settles in the dust hopper.
Multi-cyclones are in common use in industry today and most of their perfor-
mance parameters are known. This type of collector is extremely efficient
on large particles, but performance drops off rapidly for dust sizes smaller
than 20 microns (78.74x 10~5 inches) and they are not very satisfactory on
-10-
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dust sizes less than 10 microns where about 35 percent of the incinerator
fly ash falls (see Figures 1 and 3). Flow through the dust hopper caused
by gas flowing out of one tube and into another can seriously affect perfor-
mance. This is always present unless inlet gas distribution is perfect and
no tubes are plugged. Sticky or wet dust will plug the inlet spinner vanes
causing cross hopper flow. When all tubes are clean and the vortex is
sufficiently strong (3 1/2 in. w. c.* pressure drop) the multi-cylcone dust
collector can attain 80 percent collection efficiency on incinerator fly
ash, but if about a third of the tubes become plugged, the efficiency may
drop to as low as 20 percent.
The second type of mechanical collector, the large (over two feet in diameter)
involute type cyclone, operates on the same basic principle as the multi-
cyclone. Its performance is usually similar to that of the multi-cyclone
except when it is equipped with a flow splitting inlet manifold and separate
dust hoppers. This arrangement is usually free of plugging and cross-
hopper flow problems. There is a place in modern incinerator design for
mechanical collectors, but the designers must consider the device's short-
comings as well as its simplicity and cost.
The next most popular class of air pollution control equipment used in
incinerators is the wet gas scrubber. Scrubbers have received wide acceptance
as gas cleaners by industry. This would seem to be part of the natural
evolution in cleaning the gaseous effluent from an incinerator, since the
use of the combined settling-spray chamber has been so popular. Although
this may be true, it has hurt the proper adaptation of scrubbing principles
to incinerators. There is widespread misunderstanding when spray chambers,
wet baffle collectors and scrubbers are discussed. There has been adequate
data and study in the science of dust collection to dramatically illustrate
the ineffectiveness of a simple spray chamber type dust collector. The
simplest form of true scrubber is a properly designed impingement wet
baffle unit with fine sprays. A scrubber of this design can obtain over
90 percent collection efficiency if the energy expended in scrubbing is
sufficient (6 to 8 in. w.c. pressure drop).
To better understand what is involved in true gas scrubbing, the following
brief theoretical analysis is offered. Many workers have investigated the
various configurations and methods used to scrub particulate from gases, and
certain important facts are known. First, the dust particle must impact on
the water droplet to be removed and the impaction efficiency was found to
be a function of the non-dimensional group (Vr-Vs)t where:
(Vr) is the relative velocity between the water droplet and the
dust particle.
(Vs) is the settling velocity for the dust particle.
(D) is the diameter of the water droplet in microns.
(g) is the acceleration due to gravity.
* Water column
-11-
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Since (g) and (Vs) are constant for a particular dust particle of a given
size, impaction efficiency is essentially a direct function of the relative
velocity and an inverse function of the droplet diameter. If collection
efficiency is vitally dependent on relative velocity and droplet size, then
collection efficiency must be a function of the power supplied to the unit.
This fact has been verified by Semrau^, who found efficiency to have little
relation to scrubber design or geometry, but to be dependent on the
properties of the dust and on the contacting power. In a later paper^
he developed the "contacting power rule", which states that the efficiency
of a scrubber on a given dust is essentially dependent only upon the power
per unit of volumetric gas-flow rate that is dissipated in the gas-liquid
contacting process.
This means that very fine sprays must be developed and introduced in such
a manner that there is a maximum relative velocity between the dust particles
and the spray. Various types of scrubbers are in use which capitalize on
these principles. The venturi type produces the spray by drawing the water
and gases through a narrow venturi section at high velocities. Since the
spray is produced by the high velocity gas while the water and flue gases
are in contact, fly ash collection efficiency is high.
Another type of scrubber is the flooded plate type in which the flue gases
pass upward through holes in the first plate and impinge on a grid directly
above. By maintaining a water seal over the holes, the ash is separated by
a combination of impingement and wetting. There are many other types of
scrubbers, but those discussed are sufficient to illustrate the difference
between gas spraying and scrubbing and the application of the fundamental
principles of scrubbing.
The wet scrubber has been used in a few municipal incinerators operating in
the area of 6.0 to 8.0 inches w.c. pressure drop, and having a fly ash
removal efficiency in the range of 90 to 97 percent. It has the advantage
of relative compactness and relatively low first cost when compared with
other high efficiency collectors. In order to meet the high particulate
removal efficiencies indicated, the equipment normally produces a flue gas
which is saturated at the wet bulb temperature of the recirculating water.
The specific humidity of the stack effluence is therefore relatively high.
A characteristic, then, of the wet scrubber installation is an almost continuous
vapor plume at the top of the stack. While this plume is not an air pollutant
per se, it has the appearance of being one. The trend in opacity require-
ments in air pollution regulations may require the elimination of the plume.
To accomplish this, the gas must be subcooled to condense out the water
and then must be reheated to obtain a. dry plume with sufficient buoyancy.
Water rates required in scrubbers are high, and this may introduce a disposal
problem. If in the interest of economy recirculation of the scrubber water
is practiced, the recirculated water must be suitably conditioned.
Indications are that the necessary chemical treatment is complicated and to
date few incinerator scrubber systems have performed satisfactorily with
recirculation. Even with chemical treatment, scrubber maintenance problems
may be affected by the absorption of gaseous acid forming products of
combustion by the scrubbing water. Unless materials of construction are
carefully selected, maintenance costs and down time may be high, both for
-12-
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the scrubber induced-draft fans and other components in contact with the
gas stream. It should be noted that scrubbers are high efficiency dust
collection devices; they are non-selective as to the particle composition,
and they are capable of removing certain gaseous air pollutants.
In summary, scrubbers are subject to corrosion and expensive metals or metal
protection is required. The stack steam plume may be objectionable, but
scrubbers have the added advantage in that they will absorb certain gases
that would otherwise be emitted from the incinerator. In the past, the
pressure drop, along with the problems of corrosion, purification of
contaminated water prior to disposal, and costs have militated against their
use. They are, however, an attractive enough device that further research
on their application to incinerators shoud be given a high priority.
Scrubbers of a variety of designs can be successfully applied to incinerators
because collection efficiency is a function of the scrubbing energy applied.
The energy requirements for efficiencies in the range of 90 to 97 percent
vary from 6 in. to 8 in. w.c. pressure drop.
The next class of air pollution control equipment to be considered is the
electrostatic precipitator. This device has been used in industry for some
fifty years and has built an enviable reputation. In spite of this, the
fact remains that there are no precipitators operating on incinerators in
the United States at this time. New York City has recently purchased two
precipitators for incinerators, and their successful operation may signal
a new era for the electrostatic precipitator on American incinerators.
Before discussing a few of the major factors to be considered in the selection
of an electrostatic precipitator, it is best to understand the process
fundamentals. Simply stated, a precipitator operates by inducing an
electrostatic charge on the dust particle by means of a high voltage corona
discharge and by passing the charged dust-ladened gas through an electrical
field where the charged dust particle is attracted to the grounded collecting
surface and the cleaned gas passes to the clean gas outlet. This basic
theory sounds simple enough, but the performance of a precipitator is affected
by complex relationships with a great number of interrelated parameters.
The strength of the electric field is one of the utmost importance and factors
that influence it affect collection efficiency. Another factor is the charging
voltage which can range from about 40,000 to over 70,000 volts.
Other factors which seriously affect the dust migration to the collecting
plates are dust resistivity, gas temperature, moisture content of the gas,
percent of design rating (gas velocity), flow distribution and carbon con-
tent of the fly ash.
It has been found that for proper collection efficiency, the fly ash
resistivity should be between 1 x 105 ohm-centimeters and 2 x 1010 ohm-
centimeters. Dusts with a resistivity less than 1 x 10^ ohm-centimeters
are difficult or impossible to precipitate,, while dust with resistivity
greater than 2 x IQlO ohm-centimeters may be collected if the gas is treated
to reduce the resistivity.
-13-
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The general conclusion has been drawn that particles of low resistivity, on
making contact with the collector electrode, rapidly part with their charge
and acquire a heavy charge of the same polarity as the electrode. When this
happens the dust particle is driven back into the gas stream. If on the
other hand, resistance of the dust is too high, a back corona forms which
interrupts the normal precipitating action and leads to loss in efficiency.
Once the charged particle has been deposited on the collection plate, several
processes may be used to remove the dust to the hopper. These include
washing, vibrating and rapping. The dislodged particles are agglomerated
into large lumps of dust and easily settle into the collection hopper.
Experience indicates that incinerator fly ash is fine and fairly sticky and
can accumulate on discharge and collecting electrodes and in hoppers normally
used for fly ash collection. Special provisions for removal of collected
material must be provided.
One might question why the electrostatic precipitator has received such
favorable acceptance in industry and why it is considered to hold great
promise for incinerators, if it has some of the noted drawbacks. The main
reasons for acceptance are the facts that precipitators can be designed for
nearly any efficiency required, can operate over a broad spectrum of fly ash
concentration and size, and require a nominal draft loss of only about
1/2 to 1 in. w.c.
On properly operating incinerators, precipitators have the potential of
collecting more than 95 percent of the dust emitted from the furnace and
they collect sub-micron size particles with nearly the same facility as 100
micron particles. Thus the electrostatic precipitator can effectively remove
entrained fly ash from incinerator gases and an evaluation is possible
between the degree of collection and the relative size and cost of the
equipment, allowing the purchaser to match his equipment to the predicted
control requirements.
The electrostatic precipitator should definitely be considered for high
efficiency air pollution control on incinerators. It is capable of high
efficiency operation if it is properly designed for the widely differing
service encountered in incineration practice. It is therefore reasonable to
predict that this country will follow European practice where precipitators
are extensively used on incinerators.
The final class of air pollution control equipment to be discussed is the fabric
filter collector. Application of the fabric collector to incinerators is
still in the preliminary stage of development because of the high temperature
gases and the characteristics of the fly ash. The fabric collector is one
of the original cleaning devices, and much experience is available in other
industries. In fabric filters the gas passes through the fabric which is
usually arranged as tubular bags. The accumulated filter cake on the fabric
filter removes the fly ash from the gas stream. Various methods are used to
clean the filter mechanical shaking, reverse jet blowing, bag collapse,
and reverse flow backwash. The released filter cake falls to the dust hopper
for removal. In one type of fabric filter collector, the dust-laden gas
enters through the top, passes through the bag filter giving up the dust,
-14-
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and the clean gas proceeds to the stack. Filter efficiencies approach 100
percent, but their overall pressure loss may be as high as 5 to 7 inches of
water.
Cloth filtration is probably the oldest and most reliable method of removing
a high degree of fine solid particulate matter from gases. It has the ability
to remove 99.9 percent of the particulate matter, thus insuring practically
complete elimination of the plume opacity and making it a very desirable
air pollution control system. The filterhouse has not been considered sooner
because both the cost of the initial filterhouse and the bag replacements
have been prohibitive. Newer materials which guarantee long filter life
at higher temperatures have opened the way to the practical application of
filter collectors to incinerators. For example, glass cloths allow operation
at 500°F. Some research and development work will, however, be required to
insure the desired results and incinerator purchasers will have to become
accustomed to the higher cost and space requirements for this type of air
pollution control equipment. The application of these collectors to incinerators
will require even greater control of combustion and moisture to prevent the
formation of sticky soot which blinds the filter cloth. Cooling of the
gases must be carefully controlled to avoid formation of moisture on the
fabric. Either evaporative spray cooling to 700°F with no wetting of the
spray chamber followed by cool air dilution to 500°F, or indirect heat
exchange to 500°F are feasible methods of gas conditioning. At present,
filter collectors are not being used, but the increase of combustibles in
refuse and the development of continuous high temperature incinerator
operation indicates there is a future potential application for fabric filters
in incineration.
To insure proper collection performance with any of the systems discussed,
frequent thorough inspection and maintenance of air pollution control
equipment is required. If frequent maintenance is not performed, design
performance as an operating criterion is meaningless. As a further check on
normal operation, some form of pollution survey should be conducted occasionally
to see if local air-quality levels affected by a particular unit are up to
expectations and are maintaining the desired level of control. Spot checks
of dust fall and air conditions at critical locations should be conducted.
This discussion pertains to incinerator emissions, but other polluting
activities at the surface level can be very important. Refuse handling systems
often present dust problems and must be corrected by wetting agents, and
dust-tight handling systems. Ash handling can be another cause for concern
if not properly maintained.
Each of the major collection devices has been briefly discussed, and it might
be well to ask if the different types can be combined to achieve improved
performance at reduced cost. Present practice seems to indicate that there
is little advantage of combining collection systems. The type of unit most
frequently combined with one of the other collection units is the mechanical
collector. It has been used with all three of the other types of collectors,
but it is most successfully combined with the electrostatic precipitators.
The use of this combination has diminished recently since it has been found
that the mechanical collector can either aid or hinder the precipitator's
performance, depending on the properties of the ash.
-15-
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In conclusion, it may be stated that means are available to limit the
emission from an incinerator to any desired level, and that incinerator
installations of the future can meet community requirements if the com-
munity is willing to shoulder the expense.
-16-
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SECTION VII
INCINERATOR AIR POLLUTION CONTROL EQUIPMENT PERFORMANCE
Now that each of the major classes of air pollution control equipment have
been discussed, their performance will be studied in greater depth.
Particulate collection equipment performance may be classified in a number
of ways, but the most widely accepted criterion is the weight efficiency.
The weight efficiency relates the quantity of dust collected to the dust
that enters the collector with the gas. This number is only meaningful
under conditions similar to those entering the collector during the test,
including the given dust size distribution, the entering gas dust loading,
the collector energy level, the inlet gas temperature, etc. The results can
sometimes be related to other applications if the dust density, size
distribution, dust resistivity (if precipitator), collector energy level, and
gas condition are known.
A second important collector performance criterion is the fractional efficiency
curve (see Figure 3). This is sometimes called the size or grade efficiency
curve. It represents the performance of the particular collector on each
size of dust particle of a given dust density, for a given collector energy
level, gas temperature and dust resistivity (if a precipitator) .
The two efficiencies are related and can be computed one from the other if
the dust size distribution is known. This is a very important fact since
most air pollution control equipment manufacturers would prefer to guarantee
the known fractional efficiency performance for their equipment and allow
the purchaser to compute the efficiency for his particular dust.
Dust size determinations are now well accepted and follow the method and
procedures presented in the American Society of Mechanical Engineers -
Performance Test Code No. 28 "Determination of the Properties of Fine
Particle Matter". Once the size distribution of the dust to be collected
is known, the collector weight efficiency on the dust can be computed in the
following manner: First, the size distribution data must be broken into
size fractions 5 microns increments are usually satisfactory, then the
average fractional efficiency over this size range is determined from the
fractional efficiency curve and the product of the two then produces the
percent of the dust in each fraction that the unit is capable of collecting.
The sum of the computed percentages is the overall weight efficiency that
can be expected of the collector on this dust. The following example
illustrates the method, using the fractional efficiency curve given in
Figure 3 and the approximate mean size distribution for incinerator fly ash
as presented in Figure 1.
Size Weight Fractional Percent
Fraction Percent Efficiency Collected
0 ~ 5 20% 25 % 5.0%
5 ~ 10 13% 56 % 7.3%
10 - 20 16% 90 % 14.4%
20 ~ 30 9% 99.5% 9.0%
>3° 42% 100 % 42.0%
Collector Efficiency 77.7%
-17-
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TYPICAL FRACTIONAL EFFICIENCY CURVE
PERfTORMANCE' i
SRVE t-^--r-': -!:"-
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.-owfe-'i-"-;""
"- DRW -: '?
Figure 3
-------
Therefore, the collector whose fractional efficiency is given in Figure 3
would have an efficiency of about 77.7 percent on an average incinerator
fly ash. For more details on this method, see ASME's Performance Test Code
No. 21. It should be pointed out that average fly ash is like the
psychologist's normal man, i.e. very rare. It is, however, a good starting
point for an incinerator designer who must design a plant before any fly ash
can be generated.
The size and composition of incinerator fly ash and the extremely large
quantities of air used in incineration mask the real pollution potential.
As a result, stack observations are no measure of an incinerator's pollution
control. An accurate determination of the stack emissions can be obtained
only by actual test based on samples taken in the duct leaving the air pol-
lution control equipment. It is suggested that test connections be designed
into the ducting before and after the primary dust collection equipment.
This will permit the accurate determinations of the particulate emission from
the stack and the testing of the primary air pollution control equipment to
determine if it is functioning properly. Improperly performing pollution
control equipment is one major cause of much air pollution. These test
connections can be used to verify that the collection equipment is meeting
its design criteria and as proof that the stack emissions are within acceptable
levels. The necessary connections must be designed into the unit; a make-
shift arrangement to accommodate sampling at a later date is at best a
compromise.
In an earlier paragraph, mention was made of the present and projected
particulate emission standards, and in the foregoing paragraphs various
collectors and their efficiencies on a standard incinerator fly ash were
discussed. These collector performances are presented in summary form in
Figure 4 for ready reference and comparison. The local emission standards
may be used as an entry to the graph, and the efficiency required read on
the left ordinate while the right ordinate presents the class of air pollution
control equipment that could be designed to meet this requirement. As an
illustration, if the ASME 1966 maximum emission level from Figure 2 is used,
one can enter Figure 4 with the 0.8 pounds of dust per million Btu and read
77 percent efficiency on the left ordinate and on the right ordinate note that
a mechanical collector could be designed for this service. Once again, the
reader is cautioned that this data is for a properly designed and maintained
collector on gas from an incinerator with good combustion conditions. The
ranges of performance presented on the right ordinate of this figure indicate
areas in which it is reasonable to expect each class of equipment to perform
if designed for the service and if proper operating conditions are maintained.
It also assumes the equipment is in good order and sufficient energy has
been used to obtain the performance. In most cases, the 35 pounds of dust
per ton of refuse leaving the furnace assumed as a basis for this graph is
a satisfactory starting point. If, for a certain type of incinerator, the
designer knows the furnace emission to be greater or less than the assumed
35 pounds per ton* a second line can be drawn radially from the 100 percent
efficiency point to the expected furnace emission on the zero efficiency
line, and the graph used as before for these new conditions.
-19-
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I
K>
O
I
Figure A
-------
This graph illustrates that with today's technology, good pollution control
is possible on modern incinerators. As mentioned earlier, the highest
efficiency collectors may require additional development to achieve their
full potential, but are available to the industry today.
-21-
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SECTION VIII
COST OF AIR POLLUTION CONTROL EQUIPMENT FOR INCINERATORS
Now that incinerator emissions have been discussed, the projected emission
regulations reviewed, and the equipment to meet these regulations presented,
the cost to incorporate these various collectors into an incineration system
will be studied. It is extremely difficult to precisely pinpoint the price
of a particular class of air pollution control equipment. Prices vary
substantially from one vendor to another, and with conditions such as the
prestige potential of the job or a lack of sufficient vendor backlog. In
addition to these factors, certain improvements in performance and reliability
cost more than a less sophisticated design of the same class of control
equipment. Therefore, all values presented in this section must be considered
estimates representative of a range of possible values. Relative costs
given here are reported for uninstalled bare equipment, f.o.b. the factory.
It is nearly impossible to quote "designed and erected" values because
local construction uncertainties and costs are unpredictable. The local
architect-engineer involved in a particular design is best equipped to
estimate the cost of the air pollution control equipment for a given plant.
A very rough estimate of the erected price of the air pollution control
equipment only, minus any ancillary equipment, may be obtained by doubling
the f.o.b. prices. This factor of two should be recognized as a probable
median value from a range of values that begin around 1.5 and may go as high
as three.
The approximate relative cost per ton per day presented on Figures 5 and 6
was developed on the basis of the following assumptions:
1. A 600°F inlet gas temperature to the device.
2. One hundred fifty percent excess air used to burn the refuse.
3. A 5,000 Btu/pound refuse burned.
The first assumption of 600°F was selected because this temperature allows
the use of fairly standard air pollution control equipment, I.D. fans and
duct designs. It also insures adequate buoyancy at the stack outlet to assist
in the dispersion of the flue gas. One hundred fifty percent excess air was
assumed because it is felt that the continued use of some air quenching of
the gas will be practiced. With air in excess of 150 percent, there may be
insufficient furnace temperature and residence time to eliminate smoke and
odors. A refuse with a 5,000 Btu/pound heating value was used because this
is very near the present average value of mixed refuse and the trend is to
even higher values in the future. Corrections for variations in heating
value are presented elsewhere in this report, and they may be applied to
this work, if adjusted to correct for the specific plant applications. These
assumptions reduce to approximately 520 CFM per ton per day of capacity if
the gas cooling is accomplished with water quenching from the refractory lined
furnace exit temperature to 600°F. If the cooling is performed indirectly
by water heating or steam generating surfaces, or by an air heating device,
the quantity of gas to be handled is substantially reduced (See Figure 7).
-22-
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I
CO
a
o
w
w
XI
§
CM
5!
APPROXIMATE RELATIVE COST OF INCINERATOR
DUST COLLECTORS. F.O.B. FACTORY
ASSUMED CONDITIONS:
150% EXCESS AIR
600°F ENTERING COLLECTOR
WATER QUENCHED
520CFM/TPD
ELECTROSTAT:
95% EFFK
;iENCY BY WEIGHT
ICIENCY BY WEIGHT!
MECHANICAL - 80% EFFICIENCY BY WEIGHT
0 100 200 300 400 500 600 700 800 900 1000 1100 1200
INCINERATOR RATING - TONS PER DAY
Figure 5
-------
10
1
ISJ
-p-
I
O
u
H
W
H
X
O
PM
APPROXIMATE RELATIVE COST OF INCINERATOR
DUST COLLECTORS, F.O.B. FACTORY
ASSUMED CONDITIONS:
150% EXCESS AIR
INDIRECT COOLING TO 600°F
NO QUENCHING
- 365CFM/TPD
EFFICIENCY BY, WEIGHT
SCRUBBER - 95% EFFICIENCY BY WEIGHT
__JMBCHANIGAL .-
EFF|ICIENCYJBY_WEIGHT .
0 100 200 3004 400 500 600 700 800 900 1000 1100 1200
INCINERATOR RATING - TONS PER DAY
Figure 6
-------
The volume of gas to be handled in this latter case is only approximately
365 CFM per ton per day of capacity. If combustion is completed with 50
percent excess air and steam generating surface is used to control furnace
temperatures and cool the gas to 600°F, the volume of gas is reduced to
approximately 220 CFM per ton per day of capacity.
Figures 5 and 6 present the best estimates of relative f.o.b. factory prices
for high efficiency mechanical collectors (n = 80%) and 95 percent efficient
incinerator precipitators and scrubbers of varying capacities. Scrubbers
are veiled in the misunderstandings mentioned earlier, but for the type
suggested in this section, the price should be approximately the relative
values given in Figures 5 and 6.
No fabric filter unit has been considered for installation to date, and it is
difficult to estimate the probable price for the various sizes of incinerators.
This study developed information that indicates that the factory cost of a
fabric filter would be nearly the same as that of a precipitator. So, by
reading the precipitator values from Figures 5 and 6, fabric filter prices
may be approximated.
Figure 7 graphically presents the advantage in capital cost reduction for the
air pollution control equipment, I.D. fan, ducting and stack when the flue
gas is cooled indirectly. The difference is nearly directly related to the
difference shown on this graph since dust collectors are sized by actual
volume rate of gas to be handled. This difference justifies serious consideration
of the utilization of heat generated in an incinerator. If the energy
released were used to supply the power to run the incinerator plant, or to
heat the plant and surrounding buildings, this energy saving could offset
the additional cost of the converting equipment and the operating savings
could possibly reduce the cost of incinerating the refuse. Another alternative
would be to generate hot water, steam or hot air and dissipate the heat to
the atmosphere. The steam and hot water systems would require another piece
of heat exchange equipment such as a condenser or air cooler. It is believed
that there are excellent opportunities in the field of incineration heat
utilization, but more research is needed if it is to develop its full
potential.
A reduction in flue gas temperature to 600°F was assumed for the work
presented here, but a further reduction in size and cost of gas handling
equipment is possible if the flue gas is cooled even further allowing increased
volume reduction. Indications are that it may be possible to reduce the
incinerator flue gas temperature to 350°F or less before release to the
atmosphere. This would decrease the gas volume to be handled by nearly
another 15 percent. It also allows additional heat recovery which could make
energy utilization even more attractive. As was mentioned, indications
are that this is possible, but its complete acceptance will require the
expenditure of research and development effort.
If the projected emission regulations are to be mets many existing incinerator
installations must be revamped and more sophisticated air pollution control
equipment systems installed. This is a costly undertaking, and some of the
earliest units, especially those dating back before World War II will not
be upgraded. Their designs make it difficult to improve combustion sufficiently
-25-
-------
TT
m
"l
INCINERATOR FLUE GAS
FLOW COMPARISON :;;
J/Ji
ffi
IKE
:F-Fr
I
111
1
I
-26-
-------
to eliminate smoke and odor problems, and obtain sufficient burn-out. In
addition, they are usually too small to economically justify anything but
replacement. Where combustion is good, and overloading is not a problem
due to either increased refuse or refuse heating value, and where there is
sufficient space, a revamp to reduce fly ash emission will be a logical
solution. The cost of this upgrading can only be estimated on the basis of
individual installations because of the uniqueness of the various installations.
It certainly would cost more than similar equipment incorporated into a new
installation.
Table I is presented to show the interrelationship and comparison of the
various air pollution control equipment systems. This presentation is
essentially as it has already been discussed. The second column introduces
a new and important parameter the space required by each class of system.
Efficiency is repeated in Column three. If water is used, it is noted with
the quantity required in Column four. At various times, the energy required
has been mentioned, and the major constituent is pressure drop. The only
real exception to this is the precipitator and its electrical requirements;
therefore, this gauge to the' unit's energy requirements is presented in
Column five. Column six presents a very important factor that is frequently
overlooked a comparison of the relative operating cost between the various
systems. Many communities buy their units on a lowest capital cost basis
without regard for the continuing operating expense. On such a basis, it
would be difficult to justify a unit with improvements such as indirect
heat exchange. Units of this type, even when energy credits are not included,
are at best on a cost par with the simpler systems. The only criterion
should be that the proposed system meets all the projected incinerator
requirements at a minimum cost per ton of refuse when all factors are taken
into account.
-27-
-------
TABLE I
COMPARATIVE AIR POLLUTION CONTROL DATA
FOR MUNICIPAL INCINERATORS
UiLUMN 123 4 5
COLLECTOR
SETTLING
CHAMBER
MULTI-
CYCLONE
CYCLONES TO
60 IN. DIA.
TANGENTIAL
INLET
SCRUBBER*
ELECTROSTATIC
PRECIPITATOR
FABRIC
FILTER
RELATIVE
CAPITAL
COST FACTOR
(F.O.B.)
FACTORY
NOT
APPLICABLE
1
1.5
3
6
6
RELATIVE
SPACE
60%
20%
30%
30%
100%
100%
COLLECTION
EFFICIENCY
0-30%
30-80%
30-70%
80-96%
90-97%
97-99.91
«s
o o o
H H 0
0 0
P4 W rH
W i-l
H hJ pel
-------
SECTION IX
INCINERATOR ODOR AND GASEOUS EFFLUENTS
Modern incinerators are relatively free of odor and emit only minor amounts
of noxious gases when properly operated. A number of investigators have
attested to these facts and the results are quite understandable when one
appreciates the nature of refuse and the modern design practice of providing
sufficiently high temperature for complete combustion in the municipal
incinerator.
The flue gas from an incinerator is made up of carbon dioxide, oxygen,
nitrogen and water vapor which are non-pollutants and traces of carbon
monoxide, hydro-carbons, sulfur dioxide, nitrogen oxides, aldehydes and
traces of other gases which may be considered pollutants. If a particular
unit is burning material which generates these noxious gases in objectionable
quantities, a scrubber may be employed which includes a washing solution
capable of absorbing the gases. This is one of the few proposed solutions
to the noxious gas problem. No practical and efficient system for the removal
of noxious gases has been developed to date. If the increased use of plastics
creates a noxious gas problem for incinerators, research effort will have to
be devoted toward a practical solution. The incinerator is not unique in
this problem, and other industries with the problem may obtain a solution
before the incinerator requires one.
-29-
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SECTION X
TALL STACKS AND DISPERSION
The manner of discharge of the flue gases to the atmosphere affects the con-
centration of suspended dust in the ambient atmosphere and consideration of
this fact must be taken into account when designing an incinerator. The
stack is an integral part of any air pollution control system. In other
words, air pollution control is not entirely a question of the quantity of
pollutants emitted, but is also related to the atmosphere's ability to
assimilate these pollutants without adverse effects. Emission control by
dispersion effectively utilizes the atmosphere's capacity for such assimilation.
It provides for the optimum combination of such factors as stack height,
buoyancy, meteorology, and topography. To accomplish this, it is necessary
to study atmospheric conditions surrounding the plant and to determine air
flow patterns and ventilating capabilities of the region. Model studies
have been found to provide very valuable assistance. What is desired is an
ability to predict the dispersion of combustion products over a sufficiently
wide area so as to reduce pollution concentrations at any location to
amounts well within any projected air quality control level.
The term "dispersion" for purposes of. this discussion refers to the movement
of a polluted parcel of gases, either vertically or horizontally, and its
simultaneous dilution with fresh air.
Pollutants are dispersed horizontally by movement and mixing with air as the
parcel moves parallel to the earth's surface with the existing wind. Vertical
dispersion results from an exhaust stack discharging a warm polluted parcel
which moves upward while mixing with fresh air at higher elevations. Certain
phenomena restrict these activities and must be taken into consideration
when evaluating plant dispersion capability. One of the most severe natural
impediments to proper dispersion is thermal inversion of the atmosphere.
This atmospheric condition is defined as a temperature increase with height
rather than the normal decrease in temperature. This restricts the vertical
dispersion of the polluted parcel, and since this condition is nearly always
accompanied by low wind velocity, it tends to trap and concentrate pollutants.
The previous discussion dealt primarily with level terrain. Often it is further
complicated by adverse topography, such as confined valleys in which the
increased pollution concentration can reach dangerous levels. Hilltops
always present a problem because air flow patterns about them can cause the
pollutant to be returned to the floor of the valley as well as cause fumigation
of the area at the top of the hill. In addition to this, the top of the
inversion will frequently be at or near the height of the surrounding hill
tops.
High stacks have been successfully applied to large steam boilers and could
offer a final degree of protection for incinerators when they are operating
under adverse conditions. The physical height of the stack is usually
specified, but in actual practice, this height is augmented by a high stack
exit velocity. This factor, coupled with the buoyancy of the hot flue gas,
produces an effective stack height which is substantially greater than the
physical stack height. The effective stack height is the sum of the actual
stack height plus the height effects due to velocity and buoyancy.
-30-
-------
If the effective stack height is great enough, the effluent can "penetrate"
an inversion and disperse at higher elevations. The ability to pierce any
inverted layer and to flow aloft above it parallel to the earth's surface,
while clearing all obstructions, is a highly effective means to insure
adequate dispersion of pollutants.
A recommended minimum incinerator stack height should be based on air
quality criteria, surrounding land use and meteorological, topographical,
aesthetic and operating factors. This minimum will not be dictated so much
by the normal incinerator operation as by the unusual operation, those
periods when the air pollution potential of a municipal incinerator is at its
greatest such as during start-up, burn-downs low furnace temperatures,
wet refuse and breakdowns. Most authorities agree that the physical stack
height above grade for gases from a combustion source should be at least
twice the height of the tallest surrounding building. Usually, this is the
incinerator plant itself, but it can be any adjacent tall building. It
becomes clear that a stack of the correct height should be part of every
incinerator installation.
-31-
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SECTION XI
REFERENCES
1. Bureau of Mines, Ringelmann Smoke Chart, Information Circular 1C 8333.
2. Semrau, K. T. Journal of the Air Pollution Control Association.
Volume X, 1960.
3. Semrau, K. T. Journal of the Air Pollution Control Association,
Volume XIII, 1963.
-32-
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PART 6
POTENTIAL ENERGY CONVERSION ASPECTS OF REFUSE
Dr. J. H. Fernandas
Senior Project Engineer
Product Diversification Department
l
Leo J. Cohan
Product Supervisor
Industrial Sales & Marketing Department
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. SUMMARY
II. INTRODUCTION
III. POTENTIAL ENERGY AVAILABLE
IV. HEAT UTILIZATION METHODS .................... 7
V. STEAM USAGE ...... .....................
VI. INCINERATOR-GAS TURBINE ..................... 15
-i-
-------
SECTION I
SUMMARY
Incineration of refuse offers an excellent solution for the volume reduction
required since this method produces energy in a form which can be readily
harnessed and utilized to offset the cost.
Some of the prospects are:
1. Regenerative feedwater heating
2. District heating
3. District air conditioning
4. Refrigeration
5. Desalination
6. Separately fired superheaters
7. Incinerator gas turbine
The control of off gases and waste water and the removal of their con-
taminants can be accomplished and managed through process engineering
applications. However, there are many problems and the solutions are
complex. A fresh creative approach to come up with optimum solutions in
each particular instance is required.
-1-
-------
SECTION II
INTRODUCTION
The total quantity of solid waste that is generated in the United States
is given in Volume I, Municipal Inventory as 7.2 pounds per capita per day.
Based on our population, this would amount to approximately 525 billion
pounds per year. This is enough to cover the states of New Jersey
1 3/4 inches deep or Connecticut 3 inches deep. Simply stated, with
quantities of this order of magnitude, communities are running out of land
for waste disposal. (Economics dictates a more efficient use of land.)
Waste is being generated at a rate faster than the population increase
and emphasis, by both Federal and State Governments, is being placed on
more efficient methods of disposal.
While many methods of solid waste disposal and reduction have been pro-
posed and are currently being considered, incineration appears to satisfy
more of the basic needs than other methods. It is a method which reduces
the refuse to a minimum volume, destroys the bulk of the noxious odors
and putrescible substances, and leaves a sterile landfill.
Modern incineration is used for disposal of a wide variety of wastes, the
characteristics of which have changed because of new processing and
packaging techniques. In the past, refuse contained approximately 65 per-
cent garbage by volume, often resulting in an overall moisture content in
excess of 50 percent. This approaches the point where auxiliary fuel is
required to sustain combustion with suitable furnace temperatures. Today
refuse may average 10 percent or less garbage, with an overall moisture
content of 15 to 20 percent. It is characterized by large quantities of
paper bags, crates, and similar dry, combustible material. Although much
bulkier, it is more easily burned in incinerators of adequate design.
Industrial refuse has also changed, especially with the increased use of
plastics and other synthetic materials, many of which have high heating
values with little or no moisture or ash. The variable appearance of
refuse is belied by chemical analysis which is quite uniform, as much of it
is produced from wood and similar cellulose raw materials. Laboratory tests,
as well as theoretical calculations, show that the average heating value of
such cellulose by-products is about 8,000 to 9,000 Btu per pound of
combustible. The major variables are the moisture and ash or inert
ingredients, and these are not difficult to determine on a test basis.
Incineration is a thermal reduction process and, as such, is a series of
dependent and independent variables. If we were to establish overall
parameters without being hampered by present prejudices, we could approach
incineration by analysis without dimension. Many factors would fall out
and three functional dependent variables would remain refuse storage and
handling, furnace and auxiliary equipment, and residue handling. These in
varying degrees, fix the equipment size, loading, and arrangement.
-2-
-------
While recognizing the interplay of the variables, this section will discuss
some of the untapped potential for an integrated buring system. It will
also present a few energy utilization schemes that offer probability of
sound economic trade-offs.
-3-
-------
SECTION III
POTENTIAL ENERGY AVAILABLE
With the increase in heat content of refuse, the reduction of the
temperature of flue gases (or off gases) has become an extremely difficult
and expensive problem. Currently, large quantities of quenching water and
air are usual solutions to this problem. These techniques have certain
disadvantages. Quench water is quite expensive with respect to the quantities
required over 2 pounds of water per pound of refuse to quench to 600°F from
usual furnace exit temperatures. If the entire temperature reduction is
accomplished by air dilution, the "tail end" equipment, including ducting,
air pollution control equipment, I.D. fan, and stack, becomes extremely
large and expensive. Air dilution requires approximately 12 pounds of air
per pound of refuse to quench to 600°F.
If the energy in the flue gas is considered as a useful by-product instead
of the current wasteful heat dissipation, how much energy might be available,
and how do we harness this heat source and extract useful work in an
economical manner?
In order to compute the energy available, certain assumptions must be made.
Mixed refuse has a heating value approaching 5,000ABtu per pound as fired,
and this can be expected to increase in the future due to increased use of
paper and plastics in packaging. A refuse heating value of 5,000 Btu per
pound was assumed for the purpose of our calculations. This is equivalent
to 10 million Btu per ton of refuse. Ninety-five percent of the combustibles
were assumed to be completely burned. Thus, at least 4,750 Btu per pound
of refuse are liberated in the furnace for potential use as by-product
energy. To determine how much of this heat could be reasonably converted to
a more useful form of energy, it was assumed that the inlet air temperature
was 80°F and that 50 percent excess air was used in the combustion process.
To compute the quantities of air and flue gas involved, the ultimate analysis
of the 5,000 Btu per pound mixed refuse must be known, and the following
composition was chosen:
Carbon 27.0 percent
Hydrogen 4.5 percent
Oxygen 22.0 percent
Moisture 23.0 percent
Non-Combustibles 23.5 percent
It was assumed that the combustion exhibits a hydrogen preferential and that
the 5 percent unburned combustible is entirely attributable to carbon.
Thus, the unburned carbon reduces the heating value by 250 Btu per pound.
The unburned carbon percentage was calculated to be 1.7 percent based on a
higher heating value of carbon, 14,500 Btu per pound. This quantity was
subtracted from the carbon percentage in the ultimate analysis to give the
net carbon available for composition:
27.0 - 1.7 = 25.3 percent
-4-
-------
The amount of combustion air used was computed next, and it was found that
0.86 pounds of 02 per pound of refuse was required. This is equivalent to
3.72 pounds of air per pound of refuse.
The quantity of flue gas, produced by the combustion process, was determined
from the foregoing results:
Carbon burned 0.253 Ib./lb. of refuse
Hydrogen 0.045 Ib./lb. of refuse
Oxygen 0.220 Ib./lb. of refuse
Moisture 0.230 Ib./lb. of refuse
Combustion air (50% Ex. Air) 5.580 Ib./lb. of refuse
Flue gas (WFG) 6.328 Ib./lb. of refuse
The energy available may now be computed if the exit gas temperature is
chosen. A temperature of 600°F was assumed because it is the most common
value found in incinerator design today. It should be pointed out that
this value could be as low as 350°F and that as much as 15 percent more
energy could be made available at this lower temperature.
The heat loss to the stack because of the moisture content of the flue gas
was computed as follows:
0.045 (Hydrogen) x 9 = 0.405 pounds moisture per pound refuse
Moisture in fuel = 0.230 pounds moisture per pound refuse
Neglecting the moisture in the air, the pounds of moisture in the flue gas
(Wm) is:
0.635 pounds moisture per pound refuse
Heat loss in the flue gas (Qm) is:
Qm + wm (Hs600 - Hf8o)
where:
Hs600 = Enthalpy of steam at 600°F and 1 psi
HfgQ = Enthalpy of water at 80°F
/.Qm = 0.635 (1335.7 - 48.0) = 816 Btu per pound refuse
Next the dry gas loss was determined:
Total flue gas = 6.328 pounds per pound refuse
Moisture - 0.635 pounds per pound refuse
Dry flue gas = 5.693 pounds per pound refuse
-5-
-------
The dry gas heat loss (Qdg) is:
Qdg = Wa (Hg600 - Hg80>
where:
H 6Q0 = Enthalpy of gas at 600°F
(approximated as air)
H go = EnlSialpy of gas at 80°F
'Qdg = 5.693 x 126.9 = 720 Btu per pound refuse
The sum of these two losses equals 1,550 Btu per pound refuse. This value
was adjusted for radiation and other unaccounted losses, and the total heat
loss in the flue gas was approximated at 1,600 Btu per pound refuse. The
energy available for use as a by-product may now be determined:
Btu liberated = 4,750 Btu per pound refuse
Flue gas loss - 1,600 Btu per pound refuse
Energy available = 3,150 Btu per pound refuse
This is equivalent to 6.3 x 10° Btu per ton of refuse, and when related to
a 400 ton per day incinerator (16.7 tons per hour), it represents 105
million Btu per hour. Steam generation usually requires about 1,050 Btu
per pound; therefore, the available energy can generate approximately 100,000
pounds of steam per hour. If this steam is used in a steam power cycle,
with an efficiency of 25 percent, it can produce 7,300 kwhr of electricity.
These values indicate that there is the potential of substantial return to
the incinerator operator, i.e., about 6,500 kwhr available for sale after
the incinerator requirements are met. Should the incinerator be in a
municipal complex which could use this electricity, it might be valued at
$.01 per kwhr. At this rate, it would represent a $1,560 per day credit
to the incinerator, and if the incinerator's own power requirement is
included, the value increases to $1,685 per day. If the decision was made
to sell the steam to a nearby district heating system, process plant, or
similar customer, the value might be as much as $.50 per 1,000 pounds.
This would represent a $1,200 per day income or about $360,000 per year.
These are rather attractive figures, and it seems reasonable to assume that
the future will see increasing numbers of heat recovery systems incorporated
into incinerator designs. The remainder of this paper will discuss various
schemes for the utilization of incinerator heat.
-6-
-------
SECTION IV
HEAT UTILIZATION METHODS
By atomizing oil, grading coal, or pulverizing coal, we recognize and
exploit the advantages of selective surface enlargement in terms of the
combustion process. With this surface enlargement, smaller particles can
meet and combine more readily with oxygen. In addition to the advantage of
surface enlargement mentioned above, refuse is taken from a hetrogeneous
mixture to at least a partially homogenized mixture.
Figure 1 illustrates a proposed burning system which provides the unique
features of thermal drying and maximum heat utilization. This system
requires refuse preparation and is based on all refuse being reduced to
2 inches or below (including metals). The refuse may be burned alone or in
combination with other fuels. With this method, the principle of over-feed
firing is employed and the refuse is fed into the furnace through distributors
or burner registers located high enough to allow drying of the refuse
before it reaches the grate at the bottom of the furnace. Turbulence is
provided by blowing tangentially directed streams of preheated air at high
velocity through rows of nozzles at various furnace levels. Overfire air
and underfire air are proportioned in accordance with the volatile content
of the refuse. All of the refuse passes the rows of nozzles at the various
furnace levels. When the refuse enters this highly turbulent high-temperature
gas zone, a portion will burn rapidly in suspension and the larger particles
will be dried and prepared for complete reduction when they fall to the
grate. Figure 2 illustrates the turbulent zone through which the refuse
falls and dries.
The furnace envelope for this method of refuse burning is completely water
cooled and there is a continuous ash discharge grate. The entire burning
process is carried out at temperatures high enough to destroy all of the
noxious odors and putrescible refuse.
The boiler is the conventional once-through type (non-baffled) . To
minimize corrosion and erosion, velocities in the boiler bank must be kept
low. The overall advantages of this system are: (1) permits operation at
lower excess air and (2) takes advantage of the heat absorption in the
furnace. The excess air requirement will be approximately 50 percent as
compared with 150 to 200 percent in the present conventional incinerator
units. With the smaller quantities of air to handle, fan requirements,
boiler draft loss, and fly ash carry-over will be reduced. The selection
of high efficiency air pollution control equipment is, therefore, more
economical and higher burning rates and more complete combustion can be
accomplished. With proper heat recovery equipment, unit efficiencies in
excess of 80 percent can be realized.
Equipment similar to this has been in satisfactory operation for many
years, burning millions of pounds of cellulose materials annually.
-7-
-------
SIDE ELEVATION OF UNIT DESIGNED FOR COMBUSTION
FIRING OF REFUSE, NATURAL GAS, OIL AND COAL
Figure 1
-8-
-------
TURBULENT ZONE OF FURNACE OF REFUSE BURNING BOILER
Figure 2
-9-
-------
Figure 3 illustrates another very similar method of firing; the major
difference, however, is that the refuse must be reduced to a size below
3/4 of an inch. The refuse is fed by high pressure - low volume air to
centrifugal drying towers where hot air from the regenerative type
Ljungstrom air heat dries the refuse. It is then transported and fired
tangentially to utilize maximum heat absorption in the furnace.
As mentioned previously, this system requires preparation of all refuse to
a small size and, in addition, metal recovery prior to injection in the
furnace should be considered. The bottom of the furnace is the well known
Coutant type. A very small grate is available to collect material (less
than 5 percent) which might fall in this zone.
The conveying system is a proven system, capable of transporting properly
sized material. Actual systems are in successful operation conveying cellulose
material, such as wood chips and barks many miles. The ability to convey
this material may also open up the possibility of locating the firing
equipment at a source removed from the refuse inlet position.
Because of the varying nature of refuse, its energy conversion systems are
probably best suited to base-load applications. The irregularity of flow
and variable heat content would impose serious feed and control problems
for process applications. These require close temperature and pressure
control.
Figure 4 is a schematic of a proposed method by which water cooled furnaces
can be used to affect a trade-off with air pollution devices without use of
the by-product steam or hot water. By utilizing a completely water cooled
furnace, low excess air can be achieved. Furnace exit temperatures will
probably be around 1,500°F, thus minimizing the size of other heat absorbing
equipment in the system. Water spraying or a gas turbine could be utilized
to reduce the furnace exit gas temperature from 1,500°F to a manageable
600°F. The quantity of gas requiring temperature reduction is lower,
i.e., 50 percent excess air as compared with 150 to 200 percent in a con-
ventional incinerator and, therefore, if spraying is used, the quantity of
water required is less.
The heat absorbed would be approximately 100 Btu per pound of water
circulated in the water cooled furnace. The heat absorbed in the water
must be dissipated by heat exchangers, such as water to water or water to
air (fin-fan coolers) heat exchangers.
In a simple expansion of the system, convectors may be substituted for the
heat exchangers and we now have a modern high-temperature hot water heating
system. This system is being used to satisfy many heating and air con-
ditioning requirements. It lends itself to large area heating and all
that is proposed here is consideration of the source of energy - refuse
rather than fossil fuel.
-------
PNEUMATIC TRANSPORT SYSTEM FOR FIRING SOLID FUELS
CONVEYOR
HP BLOWERS/
TO
OUST COLLECTOR
AND F. D. FAN
F.O. FAN
Figure 3
-11-
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^WATERWALLS
WATER FLOW SCHEMATIC
EXPANSION TANK
= WATERWALLS
CIRC.
PUMPS
A
I COOLER I | COOLER |
^x^.
Figure
-12-
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SECTION V
STEAM USAGE
In the previous paragraphs, the quantity of heat available and methods for
producing steam with the heat were mentioned. Possible uses of the steam
will now be discussed.
In the section on potential energy available in an incinerator, a few
possibilities were mentioned for the sale of by-product steam. These
included the production of power and the sale of steam to a nearby district
heating system or process plant. Power production is one of the most
obvious and often suggested uses for the incinerators' heat. Incinerator
power generation is not without drawbacks. Knowledge of incinerator
combustion is not complete and there are corrosion problems which are some-
what unpredictable because of inconsistency of the fuel and the frequent
presence of unusual substances in the refuse. Factors such as these raise
questions as to the availability, on a continuous basis, of energy from an
incinerator plant. At the present state of development, down-time might
conceivably limit the application of incinerator heat to straight power
generation.
The power industry is studying these problems and without a doubt, solutions
will be found. It should be recalled that about forty years ago when the
use of pulverized coal was first inaugurated its availability was rather
limited, but at the present time a major portion of the world's power is
generated with it. A parallel development is certainly possible in
incineration.
If it is considered advisable to sell steam to a power company rather than
get involved in electrical distribution systems, certain possibilities
are available, (jlhe steam at a specified temperature and pressure could be
supplied to the steam electrical generating station and used in the regenerative
feedwater heating portion of the power plant cycler/ This would free the
main cycle steam from the heating task and full steam flow could be utilized
in the turbine to generate power. This would isolate the two steam flows
which is particularly attractive because power plant operation requires
very exotic water conditioning, while the incinerator" system does not
impose such severe water restrictions. In a similar scheme, the power
plant could use the incinerator's steam to preheat combustion air. Steam coil
air heaters are not new, but the use of incinerator steam to preheat
combustion air is. The steam air heater could even be enlarged sufficiently
to allow a substantial increase in the economizer. An enlarged economizer
would do all of the feedwater heating, once again releasing the main cycle
steam to power generation.
The use of incinerator by-product steam or hot water in district heating
systems or process plants has been mentioned. This is another possible use
for the steam, and should be given prime consideration.
-13-
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Thinking should not be rigorously restricted to the sale of steam or hot
water. Steam can produce chilled water in an absorption or evaporative
type cooling system, and the sale of chilled water for summertime air
conditioning or year-round refrigeration is a distinct possibility. With
the trend toward air conditioning, a heating and cooling system would have
certain distinct advantages. The same pipes that transport hot water in
the winter could be used for chilled water in the summer.
The modern municipal complex, including the sewage treatment plant,
municipal garage, incinerator, and possibly the office building and water
works, requires both space and water heating as well as some process steam.
Therefore, consideration should be given to the use of incinerator steam to
accomplish these tasks.
Another possibility is condensation of the steam. This would accomplish
the first objective of incinerator steam generation, that of shrinking the
flue gas volume to be handled, but if the incinerator is situated by the sea
this introduces the further possibility of sea water desalination. (This
has been successfully applied so details will not be presented here.)
With fresh water as a by-product, a neighboring power plant could be supplied
with make-up water needed for the steam cycle, saving the cost of producing
such water. Also the municipal complex has a need for considerable fresh
water, and the incinerator-desalinator could be established as this source.
Another logical use of the fresh water produced from an incinerator-
desalinator plant would be the municipal water system. This use of incinerator
heat is most attractive, particularly if unit availability happens to be a
problem. The water system reservoir would then ensure that demand matched
supply. Since desalination shrinks flue gas volume which in turn reduces
the cost of primary incinerator equipment, the marriage of incineration and
water supply seem natural and should be given increased study in the
immediate future.
If the incinerator installation incorporates a scrubber instead of dry dust
collection, the gas shrinking may be partially accomplished by water walls
and convection steam generating equipment. The heat absorbed can then be
used to reheat the cool clean gases leaving the scrubber. In such a system,
however, the scrubber water would have to be cooled in a spray pond or
cooling tower and recirculated to the scrubber ensuring a proper heat
balance around the unit.
Most of the systems discussed here have been suggested before in one form
or another, but convention should not restrict thinking. As an example,
the nuclear power plants presently being designed are penalized because of
the lack of superheating. Separately fired superheaters have been installed,
but fuel costs have been a problem. If waste incinerator heat was used to
superheat nuclear cycle steam, the combination might produce even lower
cost nuclear power.
We have discussed trade-offs in more conventional steam-water systems. A
different approach is considered in the next section.
-14-
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SECTION VI
INCINERATOR-GAS TURBINE
Direct hot gas powering of a prime power might seem possible if the
incinerator were pressurized, except that dust contamination would be
detrimental to the dynamic parts of any prime mover to say nothing of
the corrosion problems inherent in incinerator operation. An easy solution
to these problems might be an extra heat exchanger circuit, such as has
been discussed in the various steam and hot water designs. This may not be the
best solution, but is worth investigation. In the discussion that follows,
the use of gas-to-gas heat exchanger with a gas turbine as the prime mover
will be outlined.
The system (Figure 5) uses a standard incinerator of modern design capable
of good combustion and a gas discharge temperature from the furnace of
1,500°F. An air heater reduces the gas volume and temperature as desired,
with a minimum use of water. To accomplish this and still use a minimum
of water may require that the furnace incorporate waterwall cooling and
steam generation, or a similar solution. What is important here is that
these two requirements complete combustion and approximately a 1,500°F
exit temperature can easily be met with present day technology.
The hot flue gas from the incinerator furnace transfers most of its heat
to the air in the heat exchangers. Gas leaves the heat exchanger at approxi-
mately 600°F, a temperature considered earlier as reasonable, and is routed
to the pollution control equipment. The remainder of the gas circuit would
be similar to a conventional modern unit.
On the air side of this system, ambient air is compressed to about 90 pounds
per inch2 absolute and 500°F. The air is then heated to about 1,100°F
in the incinerator heat exchanger, and flows to the turbine for expansion
to ambient back pressure. The low pressure discharge air from the
turbine, which is still at a very high temperature of about 700°F, can
then be discharged to the atmosphere or used in another heating system.
(A portion of the air may be used in the incinerator furnace as the over-
fired air.) In flowing through the turbine, the air gives up much of its
energy and the turbine develops considerable power. Most of this power
will, however, be used to drive the air compressor and sustain the cycle,
but a small quantity of net energy is available to generate power, or drive
the l.D. fans. If D.C. power is generated, control of fan speed would be
optimum and system conditions could be easily matched with a minimum of
control. It should be noted that the hot air line between the heat exchanger
and the turbine contains a waste gate. This louvered opening can be used
to release some of the hot high-pressure air to the atmosphere to match the
power demand on the turbine. This could be accomplished while still
offering complete gas cooling to the incinerator system.
This system offers certain advantages size, minimum quantity of water
required, and design within the state of the art. For these reasons, the
system offers potential in future incinerator designs. The scheme could
be the forerunner of a completely self-sustained incinerator plant.
-15-
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INCINERATOR - GAS TURBINE
COOLED GASES TO
GAS CLEANING AND
DISPERSION EQUIPMENT
TO
ATMOSPHERE
1
GAS TURBINE
COMPRESSOR
COMPR.
^ATMOSPHERIC
AIR INLET
TURBINE
DISCHARGE AIR
GAS TO AIR
HEAT
EXCHANGER
ATMOSPHERIC
AIR RELIEF
LOUVERED
WASTE GATE
HOT FURNACE
GAS
INCINERATOR
FURNACE
HEATED AIR TO TURBINE
INCINERATOR-GAS TURBINE
HEAT UTILIZATION
Figure 5
-16-
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PART 7
THE EFFECTS OF MUNICIPAL REFUSE VARIABILITY ON
INCINERATOR EXHAUST GAS, WATER AND AIR FLOWS AND BURNING CAPACITY
Prepared
Peter y. Kalika
Project Engineer
Product Diversification Department
November 1, 1967
-------
TABLE OF CONTENTS
Page
I. SUMMARY 1
II. INTRODUCTION 2
III. CONCLUSIONS 4
IV. RECOMMENDATIONS FOR FUTURE ACTIVITIES 5
V. DISCUSSION OF RESULTS
A. METHOD OF ANALYSIS 6
B. EFFECTS OF REFUSE VARIABILITY ON EXHAUST GAS FLOW 9
C. EFFECTS OF REFUSE VARIABILITY ON AIR FLOW 11
D. EFFECTS OF REFUSE VARIABILITY ON WATER FLOW (REQUIRED
FOR GAS COOLING) 12
E. EFFECTS OF REFUSE VARIABILITY ON GAS TEMPERATURE 13
F. EFFECTS OF REFUSE VARIABILITY ON WASTE HEAT UTILIZATION ... 15
VI. REFERENCES 16
VII. NOMENCLATURE AND DEFINITION OF TERMS 17
-i-
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LIST OF TABLES AND FIGURES
Page
TABLE I
TABLE II
TABLE III
FIGURE 1
FIGURES 2 THROUGH 9
FIGURES 10 THROUGH 17
FIGURES 18 AND 19
FIGURES 20 THROUGH 24
FIGURES 25 AND 26
Refuse Composition Used in Refuse
Variability Computer Program is
Typical Computer Output, Refuse
Variability Program 19
Information from Refuse Variability 20
Computer Program on "Million BTU"
Basis
Higher Heating Value Versus Caroon 21
Net Hydrogen Ratio for Various
Percentages of Carbon (Moisture and
Ash Free)
Exhaust Gas Volume and Weight Flow 22
Versus Exhaust Gas Temperature for
Various Values of Excess Air. Higher
Heating Values of 5,200, 5,800, 6,400
and 7,000 BTU/lb. and Heat Loss
Percentages of 2 Percent and 30
Percent.
Exhaust Gas Volume Flow Versus 30
Exhaust Gas Temperature for Constant
Values of Furnace Exit Gas Temperature.
Higher Heating Values of 5,200, 5,800,
6,400 and 7,000 BTU/lb. and Heat Loss
Percentages of 2 Percent and 30 Percent.
Exhaust Gas Volume Flow at TG Versus 38
Furnace Exit Gas Temperature (TQ) for
Various Higher Heating Values. Heat
Loss Percentages of 2 Percent and
30 Percent.
40
Exhaust Gas Volume Flow at TQ Versus
Higher Heating Value for Various Heat
Losses. Furnace Exit Gas Temperatures
of 1,500°F, 1,600°F, 1,700°F, 1,800°F
and 1,900°F.
Exhaust Gas Volume Flow at TG, 500°F 45
and Saturation Versus Higher Heating
Value for Various Constant Values of
Furnace Exit Gas Temperature. Heat Loss
Percentages of 2 Percent and 30 Percent.
-ii-
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FIGURE 27
FIGURE 28
FIGURES 29 AND 30
FIGURES 31 AND 32
FIGURES 33 AND 34
FIGURES 35 AND 36
Air Weight Flow Versus Percent Excess 47
Air for Various Higher Heating Values.
Air Volume Flow Versus Percent Excess 48
Air for Various Higher Heating Values.
Air Volume Flow Versus Furnace Exit 49
Gas Temperature for Various Higher
Heating Values. Heat Loss Percentages
of 2 Percent and 30 Percent.
Percent Excess Air Versus Furnace Exit 51
Gas Temperature for Various Higher
Heating Values. Heat Loss Percentages
of 2 Percent and 30 Percent.
Water to Quench from TQ to 500°F Versus 53
Furnace Exit Gas Temperature for
Various Higher Heating Values. Heat
Loss Percentages of 2 Percent and
30 Percent.
Water to Quench from TQ to Saturation 55
Versus Furnace Exit Gas Temperature
for Various Higher Heating Values. Heat
Loss Percentages of 2 Percent and 30
Percent.
-iii-
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SECTION I
SUMMARY
The results of a computer study to assess the effects of the variability of
municipal refuse are presented in the form of graphs, tables and detailed
discussion.
It was determined that the probable variability of the characteristics of
municipal refuse can potentially cause large increases in required air,
gas and water flows at a given incinerator burning rate. These required
increases are likely to exceed the growth potential included for these
factors in today's incinerator designs, and can therefore cause potentially
serious reductions in the burning rate capacity of large incinerators.
Heat absorption equipment, if designed to provide variable absorption,
offers a potential means for compensating the effects of refuse variability.
It is recommended that a study be conducted to develop the means to project
changes in refuse composition and heating value.
1
-------
SECTION II
INTRODUCTION
A large, well designed Incinerator, incorporating the latest air pollution
control equipment must be considered one of the best means available for
the safe and economical disposal of the large quantities of refuse generated
in densely populated areas. Incinerators such as these are actually
sophisticated fuel burning systems. The compacted incinerator residue
requires far less landfill volume, and a properly processed residue
requires no cover material to assure control of insects and rodents.
One of the many problems encountered in the design of such fuel burning
systems is the variability of municipal refuse. It is a mixture of
virtually every imaginable object discarded by society and can be considered
one of the most difficult fuels to burn effectively. The refuse composition
and heating value vary from day to day and exhibit trends over periods
of time.
The design calculations leading to the sizing of the fuel burning system
include heat and material balances1 which depend upon the chemical com-
position of the refuse and on the heat content. The chemical composition
and the refuse burning rate determine the rate of combustion gases which
are released (carbon dioxide, sulfur dioxide and water vapor) and the
theoretical rate at which combustion air is required. The heat content
and the refuse burning rate determine the quantity of excess combustion air
required to maintain the temperature of the combustion gases at predetermined
levels. Thus, both characteristics of the refuse influence the quantities
of the exhaust (flue) gas and combustion air. The quantity of air or
water required for cooling of the exhaust gases is also influenced by the
refuse characteristics.
The designer usually sizes the incinerator and its auxiliary equipment on
the basis of some "typical" refuse, which may or may not be truly typical
of the region where the system will operate. The characteristics he assumes
will usually not be based on actual test, but more than likely will be
"national averages" perhaps "adjusted" for local conditions. The designer
uses this assumed refuse in conjunction with the desired burning rate, or
capacity, and bases the size of the combustion system, furnace, ducts,
fans3 pumps, valves, controls and air pollution control equipment
on the calculated air, water and gas flows which result.
The designer expects that, when refuse departs markedly from these assumed
characteristics, the incinerator operator will adjust the burning rate to
compensate for these occasional, or even day-to-day variations. Thus, if
the refuse is either excessively wet or dry as compared to the design
conditions, the operator must lower or raise the burning rate, and in
effect, change his capacity. These fluctuations are expected to be temporary,
and when conditions are normal, full capacity is expected to be restored.
-2-
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The procedure described would be entirely satisfactory, if the refuse
characteristics used were truly a typical average (plus or minus some
reasonable tolerance) for the refuse to be delivered to the incinerator
and if these characteristics were constant over the entire life of the
system. Since actual sampling of refuse characteristics is the exception,
rather than the rule, and since there has been a definite uptrend in the
combustible portion of the refuse in the past twenty years, many incinerators
may be operating today at burning rates significantly below the design
capacity established, for example, ten years ago. Projections as to
future increases in heating value are largely guess work, but increased
use of plastics could push the average heating value to as high as 7,000
Btu/pound.
The graphs and tables presented and discussed in this report are based on
the results of a computer program developed in part under Combustion
Engineering auspices and partly under Contract #Ph 86-66-163. They explore
the effects of variations in the composition and heating value of municipal
refuse in terms of exhaust (flue) gas weight and volume flow, air weight
and volume flow, excess air, heat loss by radiation and waste heat
utilization and quench water flow. The extent to which these effects
influence incinerator capacity is discussed. The results are based on an
assumed table of refuse compositions and heating values which are considered
typical of current and projected municipal refuse.
The work presented in this section was conducted by Peter W. Kalika of the
Product Diversification Department. The computer program was prepared
by Myron Holmes of the Programming Department.
-3-
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SECTION III
CONCLUSIONS
A. The probable variability of the characteristics of municipal refuse
can result in potentially serious reductions in the burning rate
capacity (tons per hour) of large incinerators.
B. Potential increases in the required combustion airflow, exhaust gas
flow, and quench water flow due to refuse variability, are likely to
exceed the growth potential included for these factors in today's
incinerator designs. The only compensation the operator can apply to
maintain operation within design limits is a reduction in burning rate.
C. Heat absorption equipment offers a potential means for compensating
the effects of refuse variability, if the equipment is designed to
permit a controlled variation of the quantity of heat absorbed.
D. The procedure described, and the resultant computer output, graphs
and tables may be used as valuable design tools in assessing the effects
of refuse variability. The sizing of fans, ducts, stacks, pumps,
valves, controls, air pollution control equipment and heat absorption
equipment may be significantly aided by the techniques described. If
an estimate of the variation of refuse composition with time is avail-
able, the designer can weigh his selections in terms of their significance
over the operating life of the system.
-4-
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SECTION IV
RECOMMENDATIONS FOR FUTURE ACTIVITIES
Although the techniques described in this report are a valuable aid in
assessing the effects of the variability of municipal refuse, they do not
provide a means to predict such variability. It is recommended that the
feasibility of providing a means to project the changes in refuse composition
and heat content be studied.
-5-
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SECTION V
DISCUSSION OF RESULTS
A. METHOD OF ANALYSIS
In order to assess the interrelationships among incinerator design
variables such as refuse heating value and composition, percent excess
air and percent of total heat release lost by radiation or absorbed
by waste heat utilization, a large number of calculations were made.
Hand calculations were made initially for a number of cases, and the
procedure was programmed for computer evaluation to permit consideration
of sufficiently narrow increments of refuse characteristics. In order
to provide the results which are independent of incinerator size, the
calculations were based on a burning rate of one ton per hour
(2,000 lb./hr.). Larger capacities may be evaluated by direct
multiplication. All parameters were given in percentages to maintain
generality.
A table of refuse higher heating values and compositions was developed
in increments of 200 Btu per pound between 43000 and 8,000 Btu per
pound. The carbon (C), hydrogen (H), oxygen (0), moisture (H20),
and non-combustibles (nonC) were determined for each heating value by
means of equation:
Eq. (1) HHV = 141 (%C) + 610 (%H - %0/8)
where:
(%C) = the percentage carbon on the "as fired basis"
(%H) = the percentage hydrogen on the "as fired basis1'
*(%0) = the percentage oxygen on the "as fired basis"
*(Assumed to be entirely combined with hydrogen to form
moisture.)
This equation is based on the individual heating values of the carbon
and hydrogen in the refuse, and is similar to the well known Dulong
formula3 except that it neglects the contribution to heating value by
any sulfur present in the fuel. Since the sulfur content of refuse is
usually low, the potential error incurred by this assumption is
insignificant. The Dulong formula has been shown to be an accurate means
for approximating the heating value of most coals, probably within 2 to
3 percent, but its application to other fuels, even to some coals, has
resulted in significant deviations. Deviations are caused by a number
of factors, including the combination of the hydrogen and carbon as
hydro-carbons. The heating value of such combinations can be
significantly different from what it would be if the carbon and hydrogen
existed separately, because the heat of combination or of dissociation
-6-
-------
would have to be considered. The value of the constants in the Dulong
equation would then have to be adjusted to account for this factor.
An example of this consideration is given by cellulose, C6H1Q05, whose
chemical composition is such that there is not net hydrogen, and
whose percentage of carbon by weight is 44.4 percent. The heating value
of cellulose is 7,526 Btu/pound. If these facts were inserted into
Equation 1 with the coefficient for carbon as the unknown quantity, it
would be calculated at 169.5, instead of the 141 given in the equation.
Mr. Elmer Kaiser^ has suggested that since municipal refuse contains
substantial quantities of cellulose, an empirical relationship similar
to Equation 1 be used for refuse, with a coefficient of 160 to 162
used for the carbon percentage. Mr. Kaiser has conducted several
sampling analyses of refuse > -* and if the suggested procedure is
applied to the heating value and chemical composition results of these
analyses, a coefficient for the carbon percentage between 150 and 160
is obtained. However, this procedure assumes that the heat released
by the dissociation of the carbon-hydrogen bonds may be entirely
lumped into the coefficient for the carbon percentage. There is no
experimental basis for this assumption. Johnson and Auth^ indicate
that the presence of the heat of dissociation makes questionable the
heat value of a portion of the carbon and probably all of the hydrogen.
There doubtless exists for typical municipal refuse an equation of the
form of Equation 1, with different values than those shown for the
carbon and hydrogen coefficients. The empirical establishment of such
an equation will require the accumulation of substantial data on refuse
chemical composition and heating values. Equation 1, based on the
individual heating values of carbon and hydrogen, permits the convenient
development of refuse compositions and will provide results which are
conservative in predicting gas, air and water flows.
Table I lists the assumed refuse compositions and heating values based
on Equation 1. The results presented by this report are based on these
characteristics. Increasing heat content is achieved primarily through
reduction in moisture and non-combustibles, with a steady increase in
both the net hydrogen (hydrogen which is not combined with oxygen in
the fuel, but which is burned with the oxygen in the air) and carbon.
The decreasing carbon to net hydrogen ratio indicates that the net
hydrogen increases more rapidly than the carbon. The use of "as fired"
compositions, as opposed to the moisture-free or moisture-and-ash-free
versions was used because it is what is actually placed in the furnace.
A trial computer run, using a factor of 162 substituted for the 141 in
Equation 1, and using the same moisture, non-combustible and net
hydrogen percentages as for the compositions in Table I, gave new
compositions with lower carbon and higher oxygen percentages. Gas,
air and water flows calculated on the basis of these new compositions
were 5 to 10 percent lower than those based on Equation 1. Equilibrium
gas temperatures were up to 7 percent higher. These deviations are not
excessive. Thus, Equation 1 may be used to develop preliminary estimates
of the relationship between refuse composition and heating value, and
-7-
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it provides a basis for analyzing the effects of the potential
variability of refuse. The computer program can, of course, be used
to analyze the air, gas and water flows and temperatures for known
refuse compositions and heating values, as well as for hypothetical
ones as discussed.
Equation 1 also neglects the heat released by the oxidation of metals
in the non-combustibles. Mr. Kaiser^ has indicated that this could
amount to approximately 2 to 3 percent of the total heating value.
Although the heating value calculated by Equation 1 will be slightly
low due to the exclusion of this contribution, the analysis is
simplified by the assumption and the important trends are unaffected.
This was verified by a trial run on the computer, using heating values
200 Btu/pound higher than those given by Equation 1. The results indicate
that a one percent change in higher heating value will result in, at
most, a one percent change in temperature and gas flows, a"nd a 1.2
percent change in quench water requirements.
Figure 1 is a moisture-and-ash-free plot of higher heating value
versus the C/(H) (carbon to net hydrogen) ratio for constant percentage
values of carbon. The compositions developed as input (Table I) to the
computer program are shown with x's; note that there is only approximately
a 5 percent range in the moisture-and-ash-free percentage of carbon.
Thuss the increasing heating value is primarily due to increases in
net hydrogen as shown by the decreasing C/(H)' ratio. This is an
expected trend in municipal refuse due to the addition of greater
quantities of plastics and other hydrogen bearing materials. The pro-
posed table of higher heating values and municipal refuse compositions
is considered typical of current and expected municipal refuse com-
positions.
The computer program, given a refuse composition and heating value, a
percent excess air, and a percent heat loss, calculates the products
of combustion for a 2,000 pound per hour burning rate. It then generates
a table of specific heats and enthalpies for the products, and performs
a heat balance to determine the equilibrium gas temperature. This
calculation assumes complete combustion, except for an assumed per-
centage of unburned carbon in the residue, and that equilibrium
conditions are achieved. Sensible heat in the residue and fly ash is
relatively small and is neglected. The hot gases are then water
quenched to 1,000°F, 750°F, 500°F, 250°F, and to saturation. The pro-
gram calculates the quench water requirements for each of these steps,
and determines the weight and volume flow at each point. The quench
water calculated is the theoretical quantity and assumes complete
evaporation. The program is also given as input characteristics of
the combustion air and quench water characteristics are incorporated
within the program by means of the heat of vaporization. Table II
illustrates a typical computer output.
Twenty-one refuse compositions are considered; eleven values of excess
air from 40 to 300 percent, and ten heat loss percentages from 2 to
60 percent. Thus, 2,310 separate cases are considered, leading to some
70,000 items of information for the twenty-one refuse compositions
calculated.
-------
A typical means for presenting this type of information is to plot air,
gas and water quantities in terms of "millions of Btu input", or as it
is referred to in this report, "millions of Btu, total heat release".
Thus, the 2,000 pounds per hour burning rate assumed in the study,
multiplied by the higher heating value, gives the total heat release
in Btu/hour. If this is then divided into the gas, air and water
quantities, information such as pounds of air per million Btu, or
pounds of exhaust gas per million Btu can be developed. This
representation has become the accepted procedure in furnace design
practice, because it permits general information to be developed
independent of specific fuel compositions.
Since this study was primarily undertaken to investigate the effects
of very specific variations in fuel composition and heating value,
the "million Btu" representation of data was not used. In this study,
gas, air and water quantities were plotted against higher heating
value, temperature and heat loss percentage for the assumed one ton per
hour burning rate.
However, the relationship of these quantities to millions of Btu of
heat released may readily be obtained from the curves which are plotted.
This is illustrated by Table III. Conversion of any of the curves to
the million Btu basis is easily accomplished by simple manipulation of
the given conditions.
B. EFFECTS OF REFUSE VARIABILITY ON EXHAUST GAS FLOW
Figures 2 through 9 illustrate one means by which the bulk of output
information can be greatly reduced. These figures are plots of exhaust
gas weight and volume flow versus temperature. All percentages of
excess air are included on one graph, but each combination of heating
value and percent heat loss will require a separate graph.
Exhaust gas weight and volume flows are plotted on the ordinates and
exhaust gas temperatures on the abscissas. Furnace exit equilibrium
temperatures are the extreme right ends of the curves and are circled.
Saturation conditions are the extreme left ends of the curves and are
boxed. Saturation is achieved entirely by water quench and no other
form of cooling is introduced between the furnace exit and the saturation
condition. Note that the circled points at the right extremity of each
curve form a "locus" of furnace exit conditions. If it is desired to
maintain a furnace exit temperature which falls between two of the
points, then the required value of excess air percentage and the
corresponding cooling curve may be interpolated.
Examination of several of the curves will serve as an example of their
use. Note that the ordinate are in "thousands" of pounds per hour or
CFM.
Figure 2 provides the weight and volume flow versus temperature for the
combustion of one ton per hour of the 5,200 Btu/pound refuse when the
heat loss is 2 percent. This is considered typical of current practice
with uncooled refractory furnace enclosures. If 100 percent excess air
-9-
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is used, the furnace exit gas temperature will be 1,840°F and the gas
flow will be 17,400 pounds per hour or 16,800 CFM. If the temperature
is reduced to 600°F by means of water quenching, the weight flow
increases to 22,300 pounds per hour, which means that 4,900 pounds per
hour or 9.8 GPM of quench water have been added to achieve the 600°F
temperature. The volume flow, however, has been reduced to 11,700 CFM.
If Figure 3 is consulted, the conditions are for 5,200 Btu per pound
refuse and 30 percent heat loss. In this case, 100 percent excess air
results in a furnace exit temperature of 1,290°F, a volume flow of
12,800 CFM and a weight flow of 17,500 pounds per hour. Note that the
use of heat absorption equipment to the extent of 30 percent heat loss
has greatly reduced the temperature and volume flow of gases leaving
the furnace. This is an excellent illustration of the saving in the
size of ducts and air pollution control equipment available from waste
heat utilization, since this equipment must be sized on the basis of
volume flow. Note that as expected, weight flow leaving the furnace is
unaffected by heat loss. The conditions at 600°F are 10,000 CFM and
20,000 pounds per hour. Thus, the water requirement is reduced to 2,600
pounds per hour or 5.2 GPM from 9.8, also a saving attributable to the
waste heat utilization.
Referring to Figure 4, the conditions are for 5,800 Btu/pound refuse and
2 percent heat loss. Examination of the 100 percent excess air case
for this combination will give us an indication of the effects of a
significant increase in contemporary heating values on incineration
equipment typical today. The furnace exit temperature is 1,890°F,
the volume flow is 18,900 CFM, and the weight flow is 19,200 pounds
per hour. At 600°F, the volume flow is 12,800 CFM and the weight flow
is 24,700 pounds per hour. Thus, 5,500 pounds per hour, or 11 GPM
of water was added to quench to 600°F. Comparison of these results
with those described for Figure 2 indicates that the 600 Btu/pound
increase in HHV (11.5%) results in an increase of 50°F (2.7%) in furnace
exit gas temperature, a 2,100 CFM (12.5%) increase in volume flow at
Tg, and an 1,800 pound per hour (10.3%) increase in weight flow at TG-
At 600°F, there is a 2,400 pound per hour (10.8%) increase in weight
flow and a 1,100 CFM (10.3%) increase in volume flow. The water
requirement increases by 1.2 GPM (12.3%). Thus the assumed increase
in heating value can cause significant increases in the load on the
exhaust gas handling and quench water systems, and could necessitate
a lower burning rate if the over-capacity is not built into fans, etc.
Since furnace exit gas temperature is usually maintained at a constant
value by dilution with excess combustion air, the exhaust gas volume
and weight flows would be increased even further if the exit temperature
were to be maintained at the original 1,840°F. Examination of the locus
of furnace exit conditions of Figure 4 shows that the excess air would
have to be increased to approximately 110 percent.
Since furnace exit gas temperature is usually maintained at some
constant value by dilution with excess air, a more realistic repre-
sentation of the data is a plot of gas flows versus temperature for
-10-
-------
constant values of furnace exit gas temperature rather than constant
values of percent excess air. In order for the computer program to
accomplish this, the excess air corresponding to assumed values of 1,500,
1,600, 1,700, 1,800 and 1,900°F furnace exit temperatures were determined
by iteration, and then all desired data were calculated at these new
values of excess air. Figures 10 through 17 illustrate this
representation of the data. From these graphs it is possible to deter-
mine the effects of heating value and heat loss variations while furnace
exit gas temperature is maintained constant.
Another example will illustrate the value of these graphs. Figure 14
gives the conditions of 2 percent heat loss and a 6,400 Btu/pound
refuse. If it is desired to maintain 1,600°F at the furnace exit, the
gas volume flow is 22,900 CFM and the flow at 600°F is determined by
following the 1,600°F curve down to 600°F where the volume flow is
seen to be 16,400 CFM. Comparisons with the results at different
heating values and heat losses may be accomplished in the same manner
as was described for the other graphs. The effects of increasing or
decreasing the setting of the temperature controller is immediately
evident by merely moving from one constant temperature graph to another.
Thus, at 6,400 Btu/pound, an increase in the temperature setting from
1,600°F to 1,700°F causes a decrease from 22,900 to 22,300 CFM.
The information shown on Figures 10 through 17 may be represented in
other ways to illustrate the relationships among the variables.
Additional graphs may be cross-plotted to show other characteristics
not clearly evident from the original curves. Figures 18 and 19 show
the exhaust gas volume at TG plotted versus furnace exit gas temperature
for various constant higher heating values, and each graph is for a
constant heat loss percentage. Figures 20 through 24 show the exhaust
gas volume at TQ plotted versus higher heating value for various per-
centages of heat loss, and each graph is for a constant furnace exit
gas temperature. Figures 25 and 26 show the exhaust gas volume at TQ,
at 500°F, and at saturation plotted versus higher heating value for
various constant furnace exit gas temperatures, and each graph is for
a constant heat loss.
EFFECTS OF REFUSE VARIABILITY ON AIRFLOW
Figures 27 and 28 give the air weight and volume flow (at 80°F)
corresponding to each of the heating values given on Table I, plotted
versus excess air percentages. These curves represent the entire data
for airflow since they are independent of heat loss percentage. In
the example given in Section B, at 100 percent excess air, the increase
in airflow when heating value increases from 5,200 to 5,800 Btu/pound
is from 3,500 to 3,900 CFM. This is an 11.4 percent increase in the
output required from the combustion air fans. If constant temperature
were to be maintained, an additional increase is required. This is
shown on Figure 29. At 5,200 Btu/pound, the furnace exit gas temperature
was 1,840°F. If this were maintained when the heating value was raised
to 5,800 Btu/pound, the air volume flow is increased to 4,050 CFM,
compared to 3,900 CFM if the temperature had been allowed to increase
-11-
-------
to 1890°F. Thus the increase in air volume flow would actually be
550 CFM or 15.7 percent. The excess air percentages corresponding to
these conditions may be read from Figure 31. As expected for 1,840°F
and 5,200 Btu/pound, the excess air is 100 percent; for 5,800 Btu/pound
and 1,840°F, it is 107 percent.
Note that airflow and excess air percentage are not independent of
heat loss percentage when gas temperature is constrained to constant
values. Increased heat loss allows the constant temperature to be
maintained with less cooling (excess) air, thereby illustrating that
waste heat utilization reduces gas volume by reducing temperature
without air or water quenching. For example, at 5,200 Btu/pound, and
at a constant temperature of 1,840°FS the increase in heat loss from
2 percent to 30 percent reduces the required air volume flow from 4,050
CFM to 2,300 CM, a reduction of 41.7 percent. Excess air is reduced
to less than 30 percent (see Figures 30 and 32).
The curves of airflow versus the constant values of TQ for various
values of heating value and heat loss percentage also give the
opportunity to evaluate to some extent, the combination of air quenching
and waste heat utilization. If at a given heating value gas temperature
is achieved by a certain airflow, the gas temperature may be reduced by
air quenching by following the line of constant HHV to the lower
temperature. Figures 29 through 32 limit this procedure to a bottom
temperature of 1,5000FS but Figures 2 through 9 allow for lower
temperatures corresponding to a maximum dilution of 300 percent excess
air. Further cooling may then be assessed on the basis of water
quenching, following the excess air curve which gave the required
amount of air quenching.
D. EFFECTS OF REFUSE VARIABILITY ON WATER FLOW
As discussed in Section B, Figures 2 through 17 assume that cooling
below the furnace exit gas temperature is accomplished by water
quenching. The water quantities required to achieve any temperature
between TQ and saturation may be deduced by subtraction on the weight
flow versus temperature curves (Figures 2 through 9). The water
quantities involved are theoretical, assuming complete evaporation,
whereas in actual practice, greater quantities will be required,
depending upon the means used to inject the water. The use of
Figures 2 through 9 to determine water requirements is limited in that
interpolation between the given values of excess air will often be
required. Figures 33 through 36 do away with this difficulty by
plotting water requirements against furnace exit gas temperatures
between 1,500°F and 1,900°F for various heating values and each graph
is for a constant heat loss percentage. Figures 33 and 34 give the
water requirement to quench to 500°F and Figures 35 and 36 the water
requirements to quench to saturation.
Examination of the graphs for quenching to 500°F shows that, as expected,
the quench water increases with increasing heating value. As the
furnace exit gas temperature is controlled at higher values, the water
-12-
-------
requirement increases further, despite reduced airflow requirements
at the higher temperatures. As the heat loss percentage is increased,
this effect is less evident and the curves flatten out. The heat
absorption reduces the airflow requirement more strongly than does the
increasing furnace exit gas temperature.
The graphs for quenching to saturation show that the water required is
essentially independent of the furnace exit gas temperature. This is
due to a balance between the reduction in gas weight flow arid the
increase in gas enthalpy with increasing temperature. The number of
Btu's which must be absorbed by the quench water is relatively constant.
As expected, increasing heat absorption reduces the quench water
requirement substantially. For example, with 5,800 Btu/pound refuse
(Figure 35) , the quench water requirement (to saturation) per ton
burned is 17.6 GPM at 2 percent heat loss. At 30 percent heat loss
(Figure 36)> it is 11.7 GPM. This is a reduction of 33.4 percent.
The reduction in quench water to 500°F from a TQ of 1,800°F is from
12.3 GPM to 8.2 GPM, also 33.4 percent. On an incinerator with a 240
ton per day, or 10 ton per hour capacity, this is a saving of 59,000
gallons of water per day. The use of the quench water graphs in con-
junction with the other information discussed in Sections B and C will
permit "trade-off" studies to be accomplished among waste heat
utilization, water quenching and air quenching.
E. EFFECTS OF REFUSE VARIABILITY ON GAS TEMPERATURE
The results already discussed under Sections B and C indicate that
variations in refuse characteristics tend to have a marked effect on
the temperature of the gases exiting from, the furnace. This temperature
is normally controlled to a constant value by air dilution, and these
effects are not always apparent in operation. However, when refuse
characteristics suddenly exhibit a drastic change, as would occur if
an excessively dry charge enters the furnace, the temperature controller
often cannot compensate quickly enough, and a large increasing temperature
excursion may occur. The combustion air dampers would open to their
maximum area in an effort to exert control. As the charge burns down,
this excess air provides too much cooling and an under temperature
excursion occurs. If the operator continues to charge the dry
material, the cycle repeats and the temperature-recorder shows a
highly cyclic pattern, and the excursions could reach 200 to 300°F.
If a sufficiently dry refuse is charged continuously-, the temperature
controller may be incapable of exerting sufficient control, and the
temperature may increase despite maximum airflow. Under these
conditions the operator may find it necessary to reduce the burning
rate and mix his charge with wetter refuse. It may even become necessary
to deliberately wet the refuse.
Figures 2 through 9 may be used to illustrate the effects of increased
refuse heating value on furnace exit temperature when excess air
percentage is held constant. For example, at 2 percent heat loss, if
heating value increased from 5,200 Btu/pound to 6,400 Btu/pound at
120 percent excess air, the furnace exit temperature increases from
-13-
-------
1,720°F to 1,800°F, and the airflow from 3,900 to 4,790 CFM. If the
air system must increase airflow further to hold temperature at 1,720,
the excess air setting would be increased to 133 percent, and the air-
flow to 5,040 CFM (See Figures 29 and 31). Thus, in order to maintain
the constant temperature with the sudden charge of dry refuse, the
combustion air system must increase its output from 3,900 to 5,040
CFM, an increase of 1,140 CFM, or 29 percent. If the incinerator had
originally been designed for normal operation with 5,200 Btu/pound
refuse, it is unlikely that the designer would have built an over-
capacity of almost 30 percent into the air system.
It is more likely that the air system will not even be capable of
maintaining the original 120 percent excess air. For example, assuming
that an overcapacity of only 15 percent was designed into the air
system, the maximum output would be 4,490 CFM. This will result in a
furnace exit gas temperature of 1,890°F (See Figure 29), or 172°F
hotter than normal, and corresponds to 106 percent excess air for the
6,400 Btu/pound refuse (See Figure 31). If the operator persists in
running the system under these conditions, he will probably encounter
severe slagging and rapid deterioration of his refractory walls. His
only means for compensating is to reduce the burning rate. It should
be noted that the foregoing discussion has assumed that sufficient
overcapacity exists in his exhaust gas system to handle the additional
gas volume flow at TQ which has increased by 23 percent (See Figure 18).
The hypothetical situation described is based on a sudden, rather severe
change in refuse characteristics, to which the operator usually will
respond by temporarily depressing his burning rate. It also illustrates
clearly the potential effects of long term variations. When the burning
rate is permanently reduced below the design value to maintain safe
operating conditions, the operator is faced with accumulating refuse due
to increasing refuse quantitiesy additional shifts, weekend operation,
and ultimately, acquisition of additional equipment must result.
If the designer decides to include a certain increment of overcapacity
to accommodate the long term increases, he must provide different over-
capacity factors for each of the gas air and water handling systems.
This was illustrated in the example, where a 15 percent overcapacity
in the air system resulted in a requirement for a 23 percent over-
capacity in the exhaust gas handling system.
The output data from the computer study also gave the exhaust gas
flows at various temperatures below the furnace exit gas temperature,
down to saturation. These intermediate temperatures of 1,000°F.
750°F, 500°F and 250°F were achieved entirely by water quench. Of
these, 500°F is probably of greatest interest, since mechanical and
electrostatic air pollution control equipment is most likely to operate
at about this temperature. Saturation conditions are of interest in
systems that use scrubbers for air pollution control equipment. At
500°F, there is a progressive increase in volume flow of exhaust gas
with increasing heating value, while increasing heat loss reduces the
volume flow. The lower the controlled furnace exit gas temperature,
the higher the gas flow at 500°F. These relationships are well
-14-
-------
illustrated by Figures 25 and 26. For example, at 5,200 Btu/pound
and 2 percent heat loss and TG = 1,600°F, the volume flow at 500°F
is 12,100 CFM. With 5,800 Btu/pound refuse at the same conditions,
the volume flow becomes 13,800 CFM. If heat loss percentage is increased
to 30 percent, the volume flow at 5,200 Btu/pound would be 8S000 CFM.
If TQ were increased to 1,700°F, the volume flow at 5,200 Btu/pound and
2 percent heat loss would be 11,600 CFM and at 5,800 Btu/pound it would
be 13,100 CFM. At 30 percent heat loss these figures would be 7,600 CFM
and 8,700 CFM.
Saturation temperature does not vary drastically over the range of
heating values and other conditions studied. However, this is
primarily due to the steep slope of saturation line on a humidity
versus temperature chart. There will be a large variation in saturation
humidity of the gases, but only a slight variation in the saturation
temperature. For example, over the practical range of conditions
studied, the saturation temperature does not fall outside the range
from 165 to 185°F, and the saturation humidity varies from .35 to .85
pounds water vapor per pound of dry gas.
F. EFFECTS OF REFUSE VARIABILITY ON WASTE HEAT UTILIZATION
Waste heat utilization (or waste heat absorption without subsequent
utilization) offers many advantages in addition to the obvious ones
involved in reclaiming some of the energy in the refuse. If heat
absorption equipment is capable of varying the amount of heat it removes
from the gases, then compensation for the effects of refuse variability
is possible. Decreases in heating value cause increases in air and
gas volume flows and quench water requirements. The removal of more
heat from the gases can compensate for these increases. Examination
of Figures 20 through 24 shows that a constant exhaust gas volume flow
at Tg may be maintained by progressive increases in heat loss per-
centage, regardless of increases in refuse heating value. Similar
graphs may be cross-plotted from data already presented to illustrate
how volume flow at other temperatures, airflow and water requirements
may also be held constant with increasing heating value, by approximate
manipulation of the waste heat absorbed. The data with regard to heat
absorption within the furnace while furnace exit gas temperature is
maintained between 1,500 and 1,900°F, does not account for further
heat absorption equipment which may be installed downstream of the fur-
nace and which can be used to replace the water quenching equipment to
achieve various temperatures below TQ. This option was not considered
in the computer study except to the extent that Figures 2 through 9
illustrate the combinations that result in furnace exit gas temperatures
below 1,500°F.
-15-
-------
SECTION VI
REFERENCES
1. Kaiser, E. R. Combustion and Heat Calculations for Incinerators.
Proceedings of 1964 National Incinerator Conference.
2. Kaiser, E. R. Refuse Composition and Flue Gas Analyses from Municipal
Incinerators. Proceedings of 1964 National Incinerator Conference.
3. Johnson, A. J. and G. H. Auth. Fuels and Combustion Handbook. 1951.
4. Kaiser, E. R. to P. W. Kalika. Personal Communication.
5. Kaiser, E. R. Chemical Analyses of Refuse Components. Proceedings of
1966 National Incinerator Conference.
-16-
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SECTION VII
NOMENCLATURE AND DEFINITION OF TERMS
HHV
%C
%H
7,0
%H20
% Non-comb.
%NH
TG
T
sat
CFM
CFM
air
GPMquench
Higher heating value Btu per pound
Percentage by weight carbon, as fired
Percentage by weight hydrogen, as fired
Percentage by weight oxygen, as fired
Percentage by weight moisture, as fired
Percentage by weight non-combustibles, as fired
Percentage by weight net hydrogen
Equilibrium exhaust gas temperature °F
Saturation temperature of exhaust gas °F
Volume flow of exhaust (flue) gas cubic
feet per minute
Volume flow of combustion air cubic feet
per minute
Volume flow of quench water gallons per
minute
Percent Heat Loss
Carbon to Net Hydrogen Ratio
Percentage Unburned Carbon
in Residue
Exhaust Gas Flow
Percentage of total heat release (higher heating
value x burning rate) which is lost by radiation
and/or absorbed by heat recovery equipment.
The ratio of the percentage by weight of carbon
(%C) to the percentage by weight of net
hydrogen (%NH). The ratio equals %C/(%H-%0/8).
The percentage of the non-combustibles which
are made up of unburned carbon.
The weight or volume flow of all gaseous
products of combustion, including moisture in
the fuel and in the combustion air, moisture
resulting from combination of oxygen and hydrogen
and all quench water added to achieve any
particular temperature.
-17-
-------
TABLE I
REFUSE COMPOSITIONS USED IN REFUSE VARIABILITY
COMPUTER PROGRAM (PARTIAL LISTING)
(PERCENT BY WEIGHT)
Carbon to
HHV
Btu per Ib .
4,000
4,600
5,200
5,800
6,400
7,000
7,600
8,000
C%
24.0
27.3
30.4
32.5
35.7
37.7
39.8
40.5
H%
3.5
4.0
4.5
5.25
5.5
6.0
7.0
7.5
0%
20.0
22.0
24.0
26.0
26.0
26.0
30.0
30.0
H20%
30.0
24.2
21.1
18.3
16,0
16.0
12.0
11.0
NonC%
22.5
22.5
20.0
18.0
16.8
14.3
11.2
11.0
Net Hydrogen
Ratio
C/(H)
24.00
21.82
20.26
16.23
15.84
13.72
12.25
10.80
-18-
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TABLE II
TYPICAL COMPUTER OUTPUT, REFUSE VARIABILITY PROGRAM
Influence of Refuse Characteristics
Refuse HHV = 5,400 Btu per pound
Moisture Carbon Hydrogen
18.3% 30.7%
Carbon unburned
Excess air
Air flow
Combustion Rate = 2,000 pound/hour
Oxygen Non-Combustible
5.0% 26.6% 20.0%
= 4.0% (of non-combustible)
= 100.0%
Heat loss (absorption
and radiation)
= 16,170 pound/hour or 3,665 CFM (at 80°F)
= 10.0%
Equilibrium gas temperature = 1,706. 7°F
Saturation temperature = 175.3°F
Total dry products = 16,488 pound/hour
Saturation humidity
Temperature
Wet exhaust gas,*
Ib./hour
Wet exhaust gas,*
CFM
Moisture content,*
lb./hour
Moisture content,*
GPM
Quench water added,
Ib/hour
Quench water added,
GPM
= 0.535 pounds/pound DG
1,706.7°F 1,000°F 750°F 500°F 250°F 175°F
17,964 20,508 21,668 23,010 24,595 25,316
16,325 14,078 12,611 10,867 8,759 8,150
1,476 4,020 5,179 6,522 8,106 8,827
2.95 8.04 10.36 13.04 16.21 17.65
2,544 3,703 5,046 6,631 7,351
5.09 7.41 10.09 13.26 14.70
Water at 80°F necessary to quench from 500°F to saturation at 100 percent
efficiency = 2305 pounds/hour or 4.62 GPM.
* Including quench water, moisture from air and from refuse combustion.
-19-
-------
TABLE III
INFORMATION FROM REFUSE VARIABILITY COMPUTER
PROGRAM ON "MILLION Btu" BASIS
HHV
Btu/lb.
4,000
4,600
5,200
5,800
6,400
7,000
7,600
8,000
Fuel
(lb./10b Btu)
250
218
192
172
156
143
132
125
Theoretical Air
~ (lb./106 Btu)
(Figure 27)
751
751
755
745
749
747
740
738
% Excess Air
To Maintain
1,600°F
(Figure 31)
118
133
143
150
156
161
165
168
Actual Air
(lb./10b Btu)
1,637
1,751
1,835
1,863
1,917
1,951
1,960
1,976
Exhaust Gas
(lb./10b B^l
(Figure 21J_
1,830
1,920
1,990
2,004
2,047
2,073
2,077
2,086
-20-
-------
HIGHER HEATING VALUE (MOISTURE g ASH FREE)
VS C/G-0 (CARBON TO NET HYDROGEN RATIO) _
FOR VARIOUS PERCENTAGES CARBON (MOISTURE & ASH I-REE)
X REPRESENTS AS FIRED REFUSE COMPOSITIONS
BETWEEN 4000 g 8000 BTU/LB (HHV AS FIRED)
USED IN COMPUTER STUDY.
-------
COMBUSTION OF MUNICIPAL REFUSE - ONE TON PER HOUR
EXHAUST GAS VOLUME (CFM) AND WEIGHT (LB/HR) FLOW VS
EXHAUST GAS TEMP. FOR VARIOUS VALUES OF EXCESS AIR (%)
COOLING FROM TG BY WATER QUENCH WITH 80F WATER
HIGHER HEATING VALUE CONSTANT AT 5200 BTU/LB
HEAT LOSS CONSTANT AT 2% OF TOTAL HEAT RELEASE
-22-
-------
COMBUSTION OF MUNICIPAL REFUSE - ONE TON PER HOUR
EXHAUST GAS VOLUME (CFM) AND WEIGHT (LB/HR) FLOW VS
EXHAUST GAS TEMP. FOR VARIOUS VALUES OF EXCESS AIR (%)
COOLING FROM TG BY WATER QUENCH WITH 80F WATER
HIGHER HEATING VALUE CONSTANT AT 5200 BTU/LB .
HEAT LOSS CONSTANT AT 30% OF TOTAL HEAT RELEASE
-23-
-------
COMBUSTION OF MUNICIPAL REFUSE - ONE TON PER HOUR
EXHAUST GAS VOLUME (CFM) AND WEIGHT CLB/HR) FLOW VS
EXHAUST GAS TEMP. FOR VARIOUS VALUES OF EXCESS AIR (%)
COOLING FROM TQ BY WATER QUENCH WITH 80F WATER
HIGHER HEATING VALUE CONSTANT Af 5800 BTU/LB
HEAT LOSS CONSTANT AT 2% OF TOTAL HEAT RELEASE
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-24-
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COMBUSTION OF MUNICIPAL REFUSE - ONE TON PER HOUR
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-28-
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COMBUSTION OF MUNICIPAL REFUSE - ONE TON PER HOUR
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COMBUSTION OF MUNICIPAL REFUSE
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VALUES OF FURNACE EXIT GAS TEMPERATURE (TG)
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;:::::::::-::i;;:::::..:::'--::i:
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BE
) VS
CONSTANT
EMPERATURE (Tg)
TOTAL HEAT RELEASE
T AT 5800 BTU/LB
NCH. WATER AT 80F
..-.-.:.-..-:
...
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-32-
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fflrPwfl
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f! {jj -^\ '^-~~r^r\\ <\
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i |iH tjjMiFjffl Wf -ffitf Ij lj:J 1 1'lfrjttjtll | J t II 1 HI 1 1 1 1 { | ] 1
i p^t-fi ^_li?-; i Ji?£ j.-- ^ Iti -f- T j
1 IT "I H -- ilL- ill T+JJ;- -r i^l - -' j_ ---------- [I - | - --
nTFTlT j T^ "F TrT :+F:~^:Tlt tl+i "TT":"T"r~:^"'+"T:"
Mh !i|{ h-f| i-r| -J| 1 H-t \M M H|hj 1 ffl H f^H[! -1 -
me %Mffl^ |4[ [|"[] Ipfill III
ifl Hffl [mil mlilffi^
' ill :' Hi - J- -T---:tiri-:::--+::::::::-:::::
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1 " f "11 f
I j| COMBUSTION OF MUNICIPAL REFUSE
i -|T "H - i ONE TON PER HOUR
: - EXHAUST GAS VOLUME FLOW (CFM) V
'-"-' :; ±- EXHAUST GAS TEMPERATURE FOR CON
'--I .-"- IJ" VALUES OF FURNACE EXIT GAS TEMP
: ::'-~-~ - : "-- HEAT LOSS CONSTANT AT 30% OF TO
.-"-."-:: ;!- - HIGHER HEATING VALUE CONSTANT A
'-' ---- '~^-^:--'-'- COOLING FROM Tr BY WATER QUENCH
"-""--"-- " i i-p- 1 -iTTTITTTT" t 1 1" ' M ~ ' 11T "T1111f ~
-- -- -- --- -- -.-- -- :t-- -- --- £
--T-- -- - T--- -'- ~ - "
i .'±~ --.- -;::[: :;- ::_: ;-.-::.- -" ..-.-:::: . ::-":-. ::::.:::::-
. :^ J.--J:: V"-;v":::::rl:::.-r-:::::::::::::v F ::|' :.iii:
If-^--,|j.]fF|T;||._:|-.::|:|;: -|-_; : ^.: ...
il"" ' V ' ; i'tl ! "" T r " \\~ \ " ill "'"pi
F" ! I;1-'" i - i]- -! Il- H t - \ I "
I ^ "H-iJ 1fJffH UlS -if t"- 1 - ".-
!j|j|jtt|.|.|W||||pM
jii llli lihlltlfJIfflH
-- -'4--
...:-T ..;::.:. :::::::.::;:;
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5
STANT
ERATURE CTG)
TAL HEAT RELEASE
T 5800 BTU/LB
. WATER AT 80F
-"- 4
::: '.- ... .' L ; .-
i:r:"::-:r-i:.";i "" -1 it
if:" - - " .."- ' " .-:"._
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': i" - .-:_.. - + :!-T"-.:":;i
-33-
-------
^HR'B^Fff^Wff^PW
ffipffiffijp^
i i - J *( LI; ....... - - ......_ i (
....: 1 J./. ./
^^^^^BHiy
;; j]j -1.-t-r- A -jf - ... .._
::::^::::~::::3cS: ::::!!:::. :^-.-.i:u:t;f .:::::. :.::::::: cCf1
^S^B^ffliffp |^fflJS^s^₯n: |H[ 1 liitfjti EXI~
::::::-::::::: ::=: -::"":^:j"?:^"::::-fP - + |:-:: EXI~
:-:::::.:.- :;-;:: ?-,:;'::::.::.:: ":;:::: VAL
EiE;E;E:f E;;|y; :E:E::;:i.||?E|;E::EEE::p:E:E;;;EE HE/
EEEEEEiE^lEEiEEEE: -:::::-:;'/-::::::.:::::::::::::::: HIG
:::::::::::::::j-t; -.::::::::.:::::::::::::::::"::::::::: COC
". ^_::::: :::;":_ i__: -. ;__^i.
:::::..:.--::; ::;!-: I '::::. .. -::--.:::::::::::::::::::::::;:::::
..-_ ._ j _ . ...
i:"!:!EEEr"E EEE::EE5J|Wf^:ljlEEE!*5*|E^-":p:E
EEE ^:^-^:;:t^^lj:^i^^^^fe-ipff^S
- 4 ...---)-__ |_L i f 4 ~\~ " 1 r. - J- j. 4'f" "H~ ij' ""H~|
"^" ^'-' n-H- -T-i :ffl"Tft-l - t-l"Ti: t}::-"T":i -I'T ;--T U
^::BliIlB-"U'Sil-:i-l::-MEffiS
ffi||j||Mffitjj|ll;[^
EEE- :|:|:L:::f F^"- : -..| ^.Jt -' E :;::
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[[[h.;;
r ' ' r - "
ftfMplH^^^^^^^B
til ii pMsH^^^^^^M
BUSTION OF MUNICIPAL REFUSE :
ONE TON PER HOUR
AUST GAS VOLUME FLOW (CFM) VS
AUST GAS TEMPERATURE FOR CONSTANT
.UES OF FURNACE EXIT GAS TEMPERATURE (TG)
0" LOSS CONSTANT AT 2% OF TOTAL HEAT RELEASE
,HER HEATING VALUE CONSTANT AT 6400 BUT/LB
)LING FROM TG BY WATER QUENCH. WATER AT 80F
:-:::;:::::::::::::::"::::;:::;:--::-::;;:::::::;;:;:;:-;:-:;
::::::::;::::. .;.:::::::. ::::::::--::::::::: ::::-.-:.- ; " "- - - "
... .- - - ]t - - - --- - - - - - ....i
.::i;t-::r:::lJ::::::tt;::-". .^t.-.:.---^ :-:-;-|-:.-. - " ; ; ;':;.
- - 1- i? _ . _ .L^' _
Hj-!|::-:4-f:E:f^^
--U . .- . - - , . . - - . }. . - . - . - - -
-------
-ffW7
tt
.
1
-111
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
EXHAUST GAS VOLUME FLOW (CFM) VS
EXHAUST GAS TEMPERATURE FOR CONSTANT
VALUES OF FURNACE EXIT GAS TEMPERATURE (TG)
HEAT LOSS CONSTANT AT 30% OF TOTAL HEAT RELEASE
HIGHER HEATING VALUE CONSTANT AT 6400 BTU/LB
COOLING FROM TG BY WATER QUENCH. WATER AT 80F
H-
-35-
-------
T-- - !TT..:prT..TT.T jrajT.j n:..T-.. J-T-
: : ::::::::::: : it:. : tl i±h -::± ::±ri:± it: :i:: : i::± -
'-- j+--.|| ,-±- --I -.{--f -fl -l-F--f -T-T.- + -
:± :±::£fia it:: i±b:::ii-iiiit tit :i-fii_: +«I
===-:-;:==: iE;;:;;-==;:-f;=:;E|E-:-:E:E.;-=:
" ~ " t- i " ' " '
I::::::.:::::::::: ::::::::::::::::::;:..; . t.
|^ - 'f---1 f~ f f
, . . . | , | .
----;<; ; 3 - . - - - - - - - f - . f f
' \ 1 ' (
^^^^^^^^^^^^^^M^M. COM
:::::::![[::::::::.. :::::::::::: -.-' /.-,:/: ;-:.:.:r EXH
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f----,--1-j-
::..::::::::::::;:: ::::: .:::::l:t: :i.t'. :t::: .::::.:::;:::: HEA
I::::-:-::-:::::::: ::::::::::?: j::!:i:j ':::: ::::-:::::::: |-|lg
..... .- ,.J^. . J( . ,.. -
:::::;:;:::[:::l:l: E:::::E:::|i:i^:::::;::::::::::::::::; COO
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: . . : . : : : : : . .
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- - - - -
:_::'.:::.... . . - ... . : :
:.::. -:::.:1:::::- .-.:::.::::: :::::::;;:::: ::: -::.:: t ::: .
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. . - 2 > - - D < ' - - -
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+ t - + i . .. -. t. ---
- ' ' - T " ~ " ;
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jSISSptlfflfppjl^^^^^
;:EEE?:EEE^:;:-"-?!f^:-^;;-;:;-i^;!?E^;EE;":-f T--E;;:;EE;:
+ / t.- f^f - if- 'f
::::::::::;?:::::-:. .;r.:::.:::--:;;::':||i :.:: ' .: .:.'. .::.: ::::
' - - - - - - -. . ' ' j | , -
BUST ION OF MUNICIPAL REFUSE
ONE TON PER HOUR
AUST GAS VOLUME FLOW (CFM) VS
AUST GAS TEMPERATURE FOR CONSTANT
UES OF FURNACE EXIT GAS TEMPERATURE (TG)
T LOSS CONSTANT AT 2% OF TOTAL HEAT RELEASE
HER HEATING VALUE CONSTANT AT 7000 BTU/LB
LING FROM TG BY WATER QUENCH. WATER AT 80F
:::-- --;- :
-- - -- --
- -
.----. - -
' ' ' --...-..- ..-..--..
":;:::;--":: ":...:. : : : . : : . ~ ~ : ..,":. . ' .
- -- B .,..,.
- ~ .::::.:_:. ::::... : : . . . - :.-.-:: : ; ; ; . . : ':,.:;: :.:;...:::
:l(l::::::l; .::::. "L -'.::: :".,[l ::: ;:...::: "'.!!,. :. :".: :..-:
- - _.-,,.-- T .. ...
Ki(i|::|;. :;::'::: = :..:: :j: -:-.'. :.:;--:: .".:::..::"
....._._.. T ............ T! .. - _ .
: : : : ~ : : : ..""'.". :;;::'::." v . " ~ . ; " ; ' : " : * : '. " : " . ; . "~ :
:::::!. -:::::::.:::"::::--::::::-'-:.:.::. ":. ": ~: :::::. . v: " .':
-36-
-------
:--- \\ : : +:: J-:|pg::T-:::-::p'H:::::"
: E- --...- - -
HHjj 1 Hfj] 1 ftliHHj III Iftliill Ifflff Irlrff-r P T ' ^ ~
: : ; < : : : :::::::::::::::::?: ,::,' r / . .
: : : 1 : : :::::::: :::;- r^'- ,'.- ' ,' ,
- - i - - -- J-r-A't- -
: : j : : : :: :::: --j:^:. ::::.-:::::::.- :::::: COME
: : E| : : : :::::: ::?::::::::::::::::::: :::::::: EXH£
: : : : : : : 1 I:::::::::::::::::::.::::. ::::;: EXHyfi
: : ; 4 : : : ::::::;-;- :: ::::::: ::::::: VALL
SlriwfM^ HEAT
: : ::: : ::: ::: ----"- ::-" :;:;:: HIGH
^fflSsETTD^ffi^^^Hffifflj^S COOL
: : : : ::::::] * ^ :::::::::: ::r:::::t ::-::
^^fflTflfflWnTrffkflTOrtffl LH+ffiHWiTlli+fff
::;::::::;::::r:::-;:-:^-T-j:T--T. |.. T_:|::; --..._.- .-_-.
^^HififiSii iiii 1
-: F-'- + : F-":-L- -::-::::-:::: -.:::- : ['-' -'- |::::
-._-._- . j . -__ ._- .
.. . . _ _ . ____ | _ _ . . . __ _
ffij|ffiffl-ffi | |-[ jj
?..::::::-:;;:.-:::..:::.;::;..] -:::::::::::::: :
tffl ffl^lfff RJ3t[^ f j \\
/-- --£< -- -,*' ;-=-- -?'- -
trlr|"::i::4:^::^;i:^T :~-m - 1
iilpi^^^^^^^^W! 1
fj -^ |T .:-:.:r:;:EEE:|EE.:EEEE:EEEE;EEE:;EEEEEEEE:E::f-: l| |T
II lf|f ffl fflffflfflffl^^^^EBiffll-|l I ! 1 i 1 ! 1
Fl if jltn ' j^^^^^^^^plrf {i r ! ' M
+ - ---T -- ---- [ i r
1 1 -- - - i
USTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
UST GAS VOLUME FLOW (CFM) VS
UST GAS TEMPERATURE FOR CONSTANT
ES OF FURNACE EXIT GAS TEMPERATURE (TG)
LOSS CONSTANT AT 30% OF TOTAL HEAT RELEASE
ER HEATING VALUE CONSTANT AT 7000 BTU/LB
ING FROM TG BY WATER QUENCH. WATER AT 80 F
- ::--::..::::::::::::-::+:::::::.-. ..-.-.. ^\. .' |f !
["^:\""-"-"":"l"'" '^'":"'-'"':'-~i'-'~-'-''T^
-37-
-------
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
EXHAUST GAS VOLUME FLOW (CFM) AT TG VS
FURNACE EXIT GAS TEMPERATURE (TG)
FOR VARIOUS HIGHER HEATING VALUES (HHV)
HEAT LOSS CONSTANT AT 2% OF TOTAL HEAT RELEASE
T
0(
-38-
-------
|TW|4|j:j|;j||^ l||:ttH^J+pj4Wj|
5 - - "'--",
. - i . i
. j;; :: : :::::::::.;:;:::;.:. L .:: ... 1...
: ;; E ; ;;;;i :;:;;::: :;; ==:;;;;;;;,
.::;-:.-: . .. . .
rf >.:;: :: : : :::::::::;:;. :::; . . .-..,.;:. -_
3 .:--:: : :::. ::::::::::--;.;; : ...-.it:..-. ....:
£ - - ] --- - -,.. ._
;|S ; \ - \ :: j : E:E:E:EE::::E !!:|;. ';i:.^ .." ^: ^;; J.::
:::: :: ;f ! :: :::::::i::::: :::i::":/ I::::: : ::::"::::::
": J " " I:'.:;;;"':::"".":.:'-::::. .::.::::":"::-. .:"
:'.: ' : : : : :::-::::::::- """ ::-;. ::;;- :: i.::.::. .:
'l'I r " ' '. '- " "~-~- -'. ~. -~~. ~.~ ^.~-~-
-- ---
::; ff '--'--- E:E::;E::::-. COMBUSTION OF MUN
t . . ~ : ::-~- ::: UNt IUiN rth
^ I', '-'-- | :" "-- --'-:' :^ "-- EXHAUST GAS VOLUN
--:; H ' 1 -_- ::::;.; :|:; FURNACE EXIT GAS
^-r_i_4:." - - - "X" PHD \/AP T ni IQ HT PHF
;::; M ill U:l li T't^- ^ HEAT LOSS CONSTA|v
: bHI'Tt 1 T-^iBOPT- ' - !-tl"r " ~3;^? ^' ~$-~\ ^?
::: .. :jj i 1- -jj I-'|:JHT iTl f4i jj L^ i'Ji'EtttI EL
;~:; ; i Jt Li! '". ii:iTJ rv"fM liSB^I
HEftfffl-tt }||j|jffl|tt1:j lt|j-|:[UJ Lttfj l-tj 1 Ifl-ttl j | jflj-f [ 1 1 1 j ffl'fflSI
"i ~ 1
t:. :!:::. :.::::.±.:....i.::::| :i:..^: ::...;-:..:.::
"-.n;- ^F"l] 1 1 ^
::::-: :::::::::::::::::::;=::::: :":; :ij: :;-:::::::
-T ::j r J. j: J...
:- :-.;:;;;EE;;;;EE;;;;;E;;E;;E;M=:;;i![;]3;E::;;E:E;E-:;EEE:::E.;
f - t -
111 iff II II lltlTFlrflfflffl^^ 1 1 1 1 11
- - - -- -j-
. : : - ...
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_n~_- -- - ...... ..
::: VL: ::::::;:==_::."_::.:..:: :::. . . :"
jJ.LiJ.LLi L . UJ^JJjJJjJL Tnj Li.^4j4lLLl |tiftH-U Ml 1 i !
-E:-:E:|EEEEEEEEE:::E:E:.:E - '.-- ::- .-.- :-f |H
r:: ------------ ----- ------- -----
EEEEEEE;:::E:::!EEE--=;..:.E.;;.;'.'-: ; , , ^
-------------
JICIPAL REFUSE 1
( nUUK T r-
1E FLOW CCFM) AT TG VS
TEMPERATURE (TG) I
-K MtAI 1Mb VALUtb LnnVy
JT AT 30% OF TOTAL HEAT RELEASE
|P:f ':".:fll' |:"i"-i-"-: :-f:J-" - I
S||||-:f| J--E| [;-,: 1 - . j ]
"39-
-------
; E E| E :E::E ;|E|||E
: : 1 : . :. ;..:... .:: .
^ffiffil^ilfflRfBfflwtlffit
|EEEEEE:Ei:| ipEEEfiE; E = EEEE:::^|::|:::EE-::i:p:ffi-:::
ffl^BB&Hfffi^EffiBimlBwwMflffl
EH$ti44#t^ffi4-tt^^4#^
^^E^^^^^E^^^^^^ffi^ffiSliH
::;;. .-;;;. -['. .:!-- I.::::::::::::::::::::::
:.... .|.....J,|. H I. ll^.+ig.. .:.....|. .....:..
:-:::::::: COMBUSTION OF MUNICIPAL REFUSE
::::::::::: ONE TON PER HOUR
::::::::::} EXHAUST GAS VOLUME (CFM) AT Tg VS
;i;;::;;;E2 HIGHER HEATING VALUE (HHV)
::::::::::? FOR VARIOUS HEAT LOSSES (PERCENT
j||||]lfHf OF TOTAL HEAT RELEASE)
::::::::::: FURNACE EXIT GAS TEMPERATURE CTg)
::::::::::: CONSTANT AT 1500F
;!is;;;;;;;!i::;;;|;ii;;;;;;;; ii;;;:;;;iii;;;;;;;;;i;!;;;;;;;;;;;;;;;£
IW-Pfflil
lui^^p
;i!:|J;!!::!L^=;;;
, -Jj- - f L*]. (-4- .
.-;:::,.t::,:.::.....J.
^i1:-:i:h;;L J
::::----, +--
-40-
-------
-41-
-------
:!:::: ::::::::::::::::::: ::: ::::::::::: r± ::::::
-- J - ? - - ,- ,' -- - - --
;'--;' ' : ,-
I:::::::::::::::::::;:::::::::::::::::::::::: COMBUST
jiff TB| iip^^ a
nir IMrTiMB^ EXHAUST
::-::::: I::::::::::::::::::::::::::::::::::: HIGHER h
nffrnmn-nTrrrrr^ FOR VARI
::-:- ." :.:::::::::::::::::::::::::::::::::; QF TOTAI
[fftf lijJIjHjOT FURNACE
---------- .I::::::-::::::::::::::::::::::-:::: CC
r " in FT Irrn^niTTiTTTTnTn TlTniTTTinTTTrntt1t11"H"H'fH'11~H
~ - ! --- -~ :-
::::.... IT -' --? -->'- ----^- !H'::
. ..--.--... _ -
":"::::i^:;^::^:::;;:i!:ii:llf:T"
iSfrlffl ffffljffiffiffmqTffffli^ 1 1 1 1 1 1 11 ffl-tlTI rrnffiH
::::: :::::r: j ^TITT:^: T |":: |+ t' : "r :- ' ' "T "
-:T | T ::
: : : : :::.:::::::::::::::;:::._::::::: ^ ; !
:::::::::::::::: ::::::::::::::::::::::::: :::; ::::: :-
ON OF MUNICIPAL REFUSE :::::.... -
C TON PER HOUR fmffffll If 1 \\\\\\M \M
GAS VOLUME CCFM) AT TG VS : : - :
^EATING VALUE (HHV)
[OUS HEAT LOSSES (PERCENT ffljiml wJi|ill '
. HEAT RELEASE) - : - : !
EXIT GAS TEMPERATURE Or;) f[fl|ffl fj |[ I jjl^Milw
)NSTANT AT 1700F ' - -
-~" ::-: :::^:~- ::"\ :\: : : - . -
r - -- ,-
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-42-
-------
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rr^lRI IQTTHM OF MIB\ITrTPAI RFFll^F
. ONE TON PER HOUR ::~
EXHAUST GAS VOLUME (CFM) AT TG VS -]
UTpupp HFATTMT \/AI IIP ('HHV/^ --
:.. FOR VARIOUS HEAT LOSSES TPERCENT :.:
' .-_ OF TOTAL HEAT RELEASE) ;
- : FURNACE EXIT GAS TEMPERATURE (TG)
: CONSTANT AT 1800F
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4-i-
U III
-43-
-------
i-l
::j
f
fi
m
Mil
j- !
ffli
; i
^
f
if
ill
TTi
4
ur
ft
U
t'c
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
EXHAUST GAS VOLUME CCFM) AT TG VS
HIGHER HEATING VALUE (HHV)
FOR VARIOUS HEAT LOSSES (PERCENT
OF TOTAL HEAT RELEASE)
FURNACE EXIT GAS TEMPERATURE
CONSTANT AT 1900F
wmm
-44-
-------
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
EXHAUST PAS VOLUME FLOW (CFM) VS
HIGHER HEATING VALUE (HHV)
FOR VARIOUS CONSTANT VALUES OF
FURNAGE EXIT GAS TEMPERATURE (TG)
HEAT LOSS CONSTANT AT 2% OF TOTAL
HEAT RELEASE
iHr
-45-
-------
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
EXHAUST GAS VOLUME FLOW (CFM) VS
HIGHER HEATING VALUE (HHV)
FOR VARIOUS CONSTANT VALUES OF
FURNACE EXIT GAS TEMPERATURE
HEAT LOSS CONSTANT AT 30% OF TOTAL
HEAT RELEASE
-46-
-------
-~k
I
3 COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
AIR WEIGHT FLOW (LB/HR) VS
EXCESS AIR
VARIOUS HIGHER HEATING VALUES (HHV)
COMBUSTION AIR SUPPLIED AT 80F AND
50% RELATIVE HUMIDITY
i
TtTT
rait
-n1
-rl-
\
--
*
W
;
I
':
ff
S
Figure 27
-------
H
ffi
T
1
t
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
AIR VOLUME FLOW CCFM) VS PERCENT
EXCESS AIR
FOR VARIOUS HIGHER HEATING VALUES (HHV)
COMBUSTION AIR SUPPLIED AT 80F AND
50% RELATIVE HUMIDITY
f
-48-
-------
Si
Hfif
m
I
f
J:
IT-'
I
lit
--J
I-K
1
TTR
1-U
LL COMBUSTION OF MUNICIPAL REFUSE
tj ONE TON PER HOUR
[j AIR VOLUME FLOW (CFM) VS FURNACE
U EXIT GAS TEMPERATURE - TG - (F)
|i FOR VARIOUS HIGHER HEATING VALUES (HHV)
HEAT LOSS CONSTANT AT 2% OF TOTAL
HEAT RELEASE
AIR SUPPLIED AT 80F AND 50%
RELATIVE HUMIDITY
til
N-
i
-49-
-------
-50-
-------
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
AIR FLOW REQUIREMENT - PERCENT EXCESS
AIR VS FURNACE EXIT GAS TEMPERATURE
FOR VARIOUS HIGHER HEATING VALUES (HHV)
HEAT LOSS CONSTANT AT 2% OF TOTAL
HEAT RELEASE
-51-
-------
BJi
M
K
F
m
00
I
GA
Trn
IT""
if
-Mil
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
AIR FLOW REQUIREMENT - PERCENT EXCESS
AIR VS FURNACE EXIT GAS TEMPERATURE
FOR VARIOUS HIGHER HEATING VALUES (HHV)
HEAT LOSS CONSTANT AT 30% OF TOTAL
HEAT RELEASE
If"
r
"T
4-L
.MPERAT1JR
^ttrf
F
-TTT
hi-
[ill.
ff?
-52-
-------
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
WATER TO QUENCH FROM TG TO 500F (GPM) VS
FURNACE EXIT GAS TEMPERATURE (TG)
FOR VARIOUS HIGHER HEATING VALUES (HHV)
QUENCH WATER AT 80F
OF TOTAL HEAT RELEASE
HEAT LOSS CONSTANT AT
-53-
-------
COMBUSTION OF MUNICIPAL REFUSE
ONE TON PER HOUR
WATER TO QUENCH FROM TG TO 500F (GPM) VS
FURNACE EXIT GAS TEMPERATURE (TG)
FOR VARIOUS HIGHER HEATING VALUES (HHV)
QUENCH WATER AT 80F
HEAT LOSS CONSTANT AT 30% OF TOTAL HEAT RELEASE
-54-
-------
$r
- -H-!
m
w
i
l
|
COMBUSTION OF MUNICIPAL REFUSE - ONE TON PER
WATER TO QUENCH FROM TG TO SATURATION (GPM) VS :
FURNACE EXIT GAS TEMPERATURE (Tg) '-
FOR VARIOUS HIGHER HEATING VALUES (HHV) QUENCH WATER AT 80F-
HEAT LOSS CONSTANT AT 2% OF TOTAL HEAT RELEASE
il
-55-
-------
COMBUSTION OF MUNICIPAL REFUSE - ONE TON PER HOUR £
WATER TO QUENCH FROM TG TO SATURATION (GPM) VS :
FURNACE EXIT GAS TEMPERATURE CTQ) :
FOR VARIOUS HIGHER HEATING VALUES (HHV) QUENCH WATER AT 80F\
HEAT LOSS CONSTANT AT 30% OF TOTAL HEAT RELEASE '
-56-
-------
PART 8
THE COSTS OF CONVEYING SOLID WASTES BY RAIL
Prepared by
Dr. L. Koenig
Louis Koenig Research
San Antonio, Texas
November 1, 1967
-------
TABLE OF CONTENTS
At TRANSFER STATIONS
I. INTRODUCTION 1
II CONTAINER AND CRANE COSTS 3
III, RESULTS WITH FIXED PARAMETERS 10
B. FREIGHT COSTS ....................... 17
C, UTILIZATION FACTOR ..................... 23
IV, COMPUTATION METHOD ....................... 25
Vo SELECTED EXEMPLARY RESULTS . . . . .............. 38
VI. REFERENCES ........... . ............... 41
-------
SECTION I
INTRODUCTION
A parametric cost study was undertaken on the conveyance of solid wastes
ty rail. This was preliminary in nature in order to establish the general
levels of the costs involved and the effect of certain parameters on these
costs. The method generated in the study is capable of more intensive
application to assess the effect and importance of various parameters and
cost components, but only a few of these assessments are worked out in the
present report.
The conveying of solid waste by rail is a quite new development and the
New York Central Railroad has been pioneering the concept,, Grateful
acknowledgement is made to the New York Central for the information and
data supplied and for access to their plans and certain cost figures While
the physical concept was developed by the New York Central in conjunction with
a progressive solid waste contractor, and while some of the basic price data
and physical relationships are those of the New York Central system, the costs
and conclusions reached in this report may or may not reproduce in specific
Instances the quotations which the New York Central Railroad might tender
for those situations The pricing of railroad operations is extremely
complicated and noted for discontinuities in prices which arise because of
the rules of regulatory agencies or the procedures set up with labor unions,,
As a simple example, there is a discontinuity in labor costs for mainline
hauling which arises from the rule that eight hours or 100 miles constitutes
a day's work for the crew. This means that the labor cost for 110 miles
might "be twice the labor cost for 90 miles. In the present study, these
discontinuities were not taken into account because the computations would
become extremely complicated.
The basis of the New York Central system, explored here, comprises a
unitized train service originating at transfer stations and having as
destination an ultimate disposal or reduction facility (UDR) located along
the railroad line. The transfer station receives the refuse from the
collection vehicles and compresses It into long containers of rectangular
cross-section which are transferred by overhead crane to a train of flat
cars. The train departs at a regular time each day, conveying the full
containers to the ultimate disposal sitp where they are unloaded from the
train and the empty conlainers from the day before's haul are put back on
the train. The train then returns to the transfer station In time for the
next day's operation. At the ultimate disposal site, during the next day
the loaded containers are emptied, cleaned and placed back in position for
loading onto that evening's train. The present concept is that the community
will own the transfer station and the containers, the ultimate disposal
contractor will own the disposal facility Including the unloading equipment
at the site, and the railroad will supply the train of flat cars, locomotives
and crew, plus a few gondola cars for bulky Items. The community will pay
a freight charge to the railroad and an unloading and disposal charge to the
refuse contractor. In addition, they will Incur the costs of owning and
operating the transfer station and the containers. The operations studied
in this report start with the delivery of collected wastes to the transfer
-1-
-------
station and end at the unloading and loading siding just short of the
disposal facility itself. The costs for the sanitary landfill or the
incinerator at the destination must be added to the rail haul costs
presented in this report. The study is geared to the viewpoint of the
community so that charges incurred by virtue of owning and operating in
community owned facilities are termed "costs" while charges incurred by the
community by virtue of using the facilities of others are termed "prices".
Where prices are arrived at by the route of computing the operator's costs,
an appropriate mark-up is added to convert operator's costs to customer's
prices.
-2-
-------
SECTION II
CONTAINER AN& G&Sfl.B GO$TS
The container cost and the crane cost must be considered together for they
are interrelated via a derived parameter the return interval:
T = return interval, hours-time elapsed between departure of train
from transfer station with loaded containers and return of the same
train to transfer station with empty containers.
The return interval is composed of the outgoing haul time between train
departure from transfer station and train arrival at UDR facility, the
container unloading time, the loading time for the empty containers, and the
Incoming haul time.
The model of the operating system comprises that collection trucks will
begin delivery to the transfer station in the morning, utilizing some of a
reserve supply of containers later to be mentioned. The bulk of the delivery,
however, will occur between some morning deadline and some afternoon dp-adline,
so that it is required that the empty containers from the UDR site be on the
side track at the transfer station by the morning deadline of each day. The
filled containers resulting from transfer station operation will depart the
transfer station at the p»m« deadline and will arrive at the UDR facility
at an hour given by the p0m. deadline plus the one-way haul time, by
definition. The containers are immediately unloaded from the train and
simultaneously the cleaned empty containers from a previous trip are loaded
onto the train The train departs the UDR facility at such an hour as to
arrive back at the transfer station by the morning deadline. During the
daylight hours of the second day in this model the full containers at the
UDR facility are emptied, cleaned, and returned to position for reloading
on an Incoming train
This system of operation requires a number of containers in service, that Is
being conveyed in any one day's train load, sufficient to contain one day's
waste,, If the train leaving at the p.m. deadline can bring back a set of
empty containers by the a.m. deadline the next day, then there will be
required two sets of containers. If the train cannot make the deadline then
the system requires that there be an empty set of containers ready at the
transfer station at noon. This means that three sets of containers would
be required, and one additional set of containers for each additional 2k
hours in the return interval.
Let?
D = haul distance miles, and
V = average origin-to-destination on-line velocity for train,
miles/hour
O~P\ f\ -r\
Then the haul-time portion is Obviously, if Is greater than 2k
hours minus the a.m. to p.m. deadline interval, the system cannot get by
-3-
-------
with only two sets of containers, but must have three or more. If 2 D/V is
greater than h-Q hours, minus the deadline interval, it must have four or
more sets.
Let:
B = number of containers in one set, i.e. to handle the one day
solid waste design quantities
T = average time required for unloading one container from cars,
taken equal to average time required for loading one empty
container back onto cars, hours, = 1/2 time to load and uniuad
a set of containers on the car.
N = number of unloading cranes in service at UDR facility required
for design day solid waste quantities
Then:
2 BT/N,
Then:
time required for unloading and loading operation for one
day's containers at UDR facility, hours.
T = 2 D/V + 2 Bi./K , hours
k
We have already shown that if the haul time alone is greater than a definable
critical duration it is not possible to get by with two sets of containers,.
However, if the haul time is less than this, there is a possibility that two
sets of containers will suffice if the loading and unloading time at the UDR
facility is small enough such that the return interval is less than the
critical value,, In the model to be taken, the unit loading time, T. , is one
of the fixed parameters but the total loading and unloading time can be
varied by varying N^ the number of cranes. It is in this way that the cost
of containers and the cost of cranes are interrelated.
Define:
L =
Then:
inter-deadline interval, hours
interval,.
- in the a.iru to p-,m, deadline
The critical return intervals are:
2l|-L, kQ-L, _ . etc.
Consider what happens as the haul distance increases. As the distance
increases, the return interval will increase- When the return interval
reaches (2U-L) hours, then the next increment of haul distance would
require an additional set of containers. However, this necessity can be
-4-
-------
held off to a certain extent by increasing the number of cranes in service
and thus reducing the unloading time. Consider firt the case in which the
annual cost of a set of containers in several fold the annual cost
associated with the operation of a single crane. Then at some distance
slightly over a (2k-L) hour return interval it would be possible to reduce
this return interval to less than (2k-L) hours by adding a single crane, and
this would avoid the necessity of adding a complete set of containers,, Thus
it would be economic
If the distance is then again increased, it would come about that even with
the. additional crane the return interval becomes greater than 2^-L hours when
the same decision is again faced.
A series of critical times may be mathematically expressed as:
T = 2MS-1)-L hours
where:
S - Sets of containers in service - 2, 3, sets.
Now:
T + L- * *
S = (l + pIT~) where (X) signifies "the least integer equal to or
greater than "X", or in words: X if X Is an integer, the next
integer higher than X if it is not.
Regardless of the haul time, or of the inter-deadline interval, there must
be at the minimum enough cranes to perform the unloading-loading operation
in a span of 2k hours. Otherwise each day's consignment could not be handled,
Thus there is a minimum number of cranes:
1\T = fpT"R/pli)*= f r "R / 1 P ) *
lN/,-0 \ \ £ 1, U / t'-t j \ I -D / J_ £L )
k(Min, )
The load-unload time with say 2 sets of containers and this minimum number
of" cranes will be 2t B/N, /.. , and the return interval will be:
k(Min.),
2 D/'V +2B T/W ,, v
k(Min0}
Suppose this happens to be less than the critical interval 2k (S-l) - L,
or in this illustration with 2 sets (2U-L). Then consider what will happen
as the distance, that is the in-and-out haul time 2 D/V is increased. As
this is done, there will come a point at which 2 D/V + 2 B T/N /,,. v becomes
greater than 2k-L, Then the train could not meet the morning fieaalineo
This situation could be remedied bv increasing the number of sets of
containers to 3. But considering for the moment a case in which the cost of
-5-
-------
a set of containers is much greater than the cost of a single crane, then the
situation could be remedied by adding a single crane. This would augment
the cost by less than the cost of a set of containers and yet would reduce
the value 2iB /N, ,,., . to 2tB /(N, ,.,. , + l) .
k(Miru ) k(Min.)
As the distance now continues to be hypothetically increased this process could
be repeated adding 1 additional crane each time. But finally there would come
an additional crane which would bring the total cost of the cranes added to
a figure greater than the cost of an additional set of containers which could
operate now on a 2-day cycle with only N / ^ cranes.
New Let:
a = annual incremental cost of owning and operating 1 set of
containers, $/yr.-.
a = annual incremental cost of owning and operating 1 crane
under the intended conditions of service, $/yr.
Then the maximum number of cranes that may be added and still remain economic
over the alternative of an additional set of containers is:
where the symbol [[Xl], read "double bracket X" signified "the greatest
integer X", or in words: X if X is an integer, the next integer lower than
X if it is not.
There is no need to add a. number of cranes greater than this limit, since the
cost would be greater than adding an extra set of containers and dropping
back to N, /, , cranes.
k(Min»)
In the original working out of this concept there was included in the
incremental cost of owning and operating cranes a variable to account for a
number of shifts of crane operation per day and also the concept that
operating labor would amount to 8 hours per shift regardless of the length
of the shift. This is indeed likely to be the real situation, but it
presented difficulties in computation which were insurmountable without an
electronic computer whereas the amount of computation to be carried out in
this preliminary study did not warrant the use of an electronic computer.
Accordingly, the concept was relieved of the labor and it was taken that
labor costs would be incurred only during the actual hours in which the
cranes were in operation, in this being mathematically similar to fuel and
supplies., Accordingly, there remains in the a and a, terms only the fixed
costs.,
Let:
P = investment for 1 container
c
P, = investment for 1 crane
-------
The parameters for translating investment into annual cost are as follows:
i = interest rate, fraction/year
j = insurance rate, fraction/year
g = tax rate, fraction/year
m = maintenance repair and minor replacement, fraction/year
r = capital recovery factor, year-end repayments, corresponding
to i and V, fraction/year
V = amortization period, years, taken as equal to useful life
(rjgm) = fixed cost rate on capital equipment =r+j+g+m,
fraction/year
Then:
AN
k(Max.)
(rjgm)
k
When the computations are performed for a series of increasing distance,
relations are obtained as shown in Figure 1. All the terms used in this
Figure, as well as in the actual computations, have been reduced to one-way
haul time D/V, for ease in the computations, with corresponding changes to
"hall return interval", half load-unload time (which equals load time), etc.
The bottom portion of the Figure shows the relation with respect to the
number of cranes, taking N min. as 1. Starting at D/V = 0, the number of
sets of containers used is two, with one crane. This condition continues
for an extended period until at the time 12 (S-l)- !L - Br.. it is
2 Nk(Min.)
necessary to add a second crane in order not to exceed the critical half-
return interval. As D/V increases cranes are added stepwise until there is
reached the time :
- BT
V ~ -- ~
,,,. v k,M ,
K(Min. ) R(Max. )
At this point the mathematics dictates to add still an additional crane, in
this illustration the fourth addition crane. However, the economics dictates
that it would be cheaper to add a third set of containers and revert to a
single crane. This operation is diagramed by the vertical line falling back
to % = 1. In the next interval three sets are used rather than 2 and the
stepwise pattern is identical with the first stepwise pattern. Thereafter
the whole diagram is repetitive, both in D/V intervals and in % intervals,
following that for three sets.
The upper portion of the diagram indicates the cost of these steps. The cost
of adding each additional crane is a uniform amount. But when it comes to
the step of adding the fourth crane, the diagram shows at the point labelled
see text" that the cost of going to an additional set and dropping back to
one crane is less than the cost of adding another crane. The cost now with
three sets of containers again plateaus for a long interval of D/V before
repeating the stepwise pattern in cost. The cost pattern is also repetitive
both in D/V and in cost except of course that each starting point is higher
than the last, incidentally by an amount equal to the cost of adding one set
of containers .
i
-------
OPTIMUM NUMBER OF CRANES
AND CONTAINER SETS IN
SERVICE, Nkmin = l
ct:
o
a
<
to
O
O
o
u
z
z
250
200
150
12(S-1) - -
BT
2 Nkmin+ANkmax
H
12(S-l)-^
See Text
Cost of Adding (
One Crane '
12 Hours
BT
A Nk
max min
Nk
Cost of Adding One
Set of Containers
UJ
z
or
(J
LL.
O
2 Sets of
Containers
3 Sets of
Containers
BT
ML
_ "kmin
V « i
^ ^
,
ONE-WAY HAUL TIME, - - MRS.
Figure 1
-------
Adding the following parameters not previously defined:
E = men per crew on crane, number
01 = cost of fuel and supplies per hour of crew operation, $/hr
g - fraction of one set of containers In reserve (/,'
the cost quantities of interest are as follows:
Number of set of containers in use, S =
' L_ -*- D + BT + 12 Y
2 V N"~ . , + AN. ,., «
k (Min.) k(Max.)
i:
Number of cranes in use, N =
(L2 (P-1) - L, - r
2 VI
Ciane price at 20',':' markup, $/ton handled =
Fixed Labor and Supplies
1,20 N, P, (iM,^mV + o2H U BT (P,E + a )
k k ' K l
" 7x12 Q.[i~
Container cost, #/ton handled =
B(S + g)r (ri^m)
c c
312 Q.U
-------
SECTION III
RESULTS WITH FIXED PARAMETERS
In working out the exemplary cases for this report, the fixed parameters
have been given the values listed below. By fixed parameters are meant
those parameters in the equations which are maintained fixed from case to
case as the situations parameters are varied. Such fixed parameters include
container prices, labor prices, etc. As distinguished from these fixed
parameters, there are the variable or situation parameters which are primarily:
Q daily capability
U utilization factor
D haul distance
Certain of the fixed parameters are included as variable parameters on
occasion principally in order to demonstrate the relative insensitivity of
the costs to variations in values of certain fixed parameters. The price
of land is one of these. The equations provide for any set of values for
both the fixed and the variable or situation parameters, but in the exemplary
cases, the following values have been taken for the fixed parameters:
t tonnage capacity of container = 30 tons
P price of such containers, $6,000
P price of crane, $100,000
K
T one-half of load - unload time at UDR facility - 0.0333 hrs,
r capital recovery factor on containers, 0.1666 corresponding to
C 7 years life at h%
j insurance rate on containers, 0.01
g tax rate on containers, 0=01
m maintenance and minor repair rate on containers, 0.05
r capital recovery factor on cranes, 0.1666 corresponding to 7 years
k at k%
g tax rate on cranes, 0.01
k
ni maintenance and minor repair rate on crane, 0.05
P labor price, 3-50 $/man-hr.
E number of men on crane crew = 2
±k insurance rate on cranes, 0.02
-10-
-------
ak cost of supplies and fuel for cranes =1.25 $/hr.
3 reserve containers, fraction of one set =0.50
L inter-deadline interval = 7.0 hours, i.e. transfer station to "be
in operation from 9 a.m. to k p.m.
Mark-up on crane costs, fixed, labor and supplies = 20%
Mark-up on turn-around costs = 25%
The results of the numerous cases computed are too many for presentation
here since the final costs are presented in the section of this report
entitled "Computation Method", container costs being shown as Cost Schedule 2,
and crane price as Cost Schedules 3 and U. The price for the siding at the
UDR facility is shown as Cost Schedule 5
A, TRANSFER STATIONS
The transfer station comprises the installation at which the refuse is
transferred from the collection vehicles to the containers and the
containers loaded on the train. It consists of access way, building,
loading floor, hoppers into which the refuse is dumped, hydraulic
mechanism to compress the dumped refuse into the containers, and overhead
crane to transfer containers to the train, 'a siding to hold the train
being loaded, and winch or other mechanism for moving the train along
as loading proceeds. The hourly capability of an individual hopper-press
unit is remarkably high, but the daily utilization factor is low, so that
a single hopper-press unit has a capability of 125 tons per day (td).
Cost estimates on these transfer stations have been made in the range
from four hoppers to twelve hoppera. -*-
The investment in the New York area for such stations is well represented
by the equation:
CIS = 300,000 + 253,33 Q Q
where C = New York region investment for transfer station
_LO
Q = capability of station, td
Q
This equation becomes somewhat higher than the reference data above
QS = 2,000, but the equation is taken as preferable over the reference
because the reference shows an incremental unit cost for the 13th and
iVth units which is substantially less than the incremental cost for
units 11 and 12 in which themselves the trend is rising.
-11-
-------
The acres of land required is given in Reference 1 for Qg = 500, 1,000,
and 1,500,, These figures are approximated by the equation:
L = (Qg/100)
0.5
where:
L = acres of land required
Reference 1 estimates do not include a fence around the installation.
Provision is made in this study for a 6 foot chain link fence Assuming
the land is in the shape of a rectangle with one side twice the other,
the perimeter is 885-1*0° 5 Thus, the fence investment is:
0.25 ^
= 885 (Qs/100)
where:
CTTn = fence investment
-Lr
P..., = unit price of fence $/Dinear feet
r
This reduces
CIF = 28° PF
using subscripts as follows:
S = station
L = land
F » fence
The total investment then is:
C1SLF = 300'000
0.25
+P
L (
10
280
The annual costs are:
station
land
fence
,dollars
ASLF
where:
C
ASLF
^300,000 + 253.33
10
= annual cost, $/yr.
,dollars/yr,
-12-
-------
Since the purpose of the present study is primarily to explore the effect
of tonnage and distance on the rail haul cost, for most cases the capital
fractions will be standardized as follows. Capital recovery on the
station since it is to be owned by the municipality will be taken as 20
years and \% for capital recovery factor TQ = 0.0736. Insurance and
taxes or payments in leiu of taxes will be taken at 1% for fractions
js = 0.01, gs = Oo010 Maintenance will be taken as 5% per year, mg = 0.05,
The total (rjgm)s is 0,1^36. The same values will be used for the fence.
For the land there is no depreciation, but the interest is taken at H%,
for i - O.OU. Taxes or payments in lieu of taxes are taken at 0.01, gL,
and insurance at 0,005. The (ijg)L is 0.055-
With capital cost parameters fixed in this way, the annual fixed cost
on capital becomes:
C = il3,080 + 36,3T8 Qq station
o
181.82 ' land
1,0,208 P (Q-25
The relative importance of these three cost components may be assessed
by inserting certain values for price of fence and price of land. If
price of fence is taken at 7-5 $/linear foot which is a proper estimate
for the type of fence planned, and if land is taken at $1,000 per acre
in order to maximize the contribution of fence, it is found that the
fence contribution is only of the order of 1 - 2.% of the total of the
fixed costs on capital for the transfer station installation, being at
the lower figure for the maximum capability and at the higher figure
for the minimum capability. Likewise, if land is taken at the highest
reasonable price of $UO,000 per acre, it is found that the contribution
of land is in the range h - 6% being the lower at the lower capability,,
Since these percentage contributions will be diluted even further when
the costs other than for the transfer station installation are added,
such as crane and container cost, rail freight, etc.,, it is clear that
fence can be neglected as a cost component and taken care of by
adjusting the station component upwards by 1.5% giving:
C.QTT, - U3,726 + 36.92U Q station
AD.br o
_L_
181.82
-13-
-------
The same argument applies to land contribution; this is discussed in
Section V.
In addition, there will toe required at the transfer station a siding
for handling the cars, in length twice the length of the train. This
cost will probably have to be borne by the community.
As discussed in the section on cranes and containers, if each car handles
three containers, the number of cars required is:
Thus, with 89 foot cars, the length of the siding is:
«
2 x 89 x(|-J , feet
With a 20 foot right-of-way, the acres required for the siding is:
*
.08172
If it is taken that this siding land may be purchased for the same price
as the main acreage and that the annual fixed factor is the same as the
main land, then the annual cost of land for the siding becomes:
PL
1000
The cost of the track for the siding itself is taken as $7 per foot-l-
and with the annual cost factor the same as for the station itself (i.e,
0.1^36) the annual cost for the siding track becomes:
*
178.9 l£)
It is noted that the same length of siding will be required as part of
the facilities at the UDR site, taken as a cost of the UDR contractor,-,
This completes the fixed costs for the transfer station. The operating
costs are derived from basic data in Reference 1 which provides estimates
of labor type and cost for 500, 1,000 and 1,500 ton per day stations in
New York City area. The labor breakdowns and the utilities cost were
extended by estimation at 125 and 2,000 tons per day. The utilities
include light, water, gas, phone, heating and electric energy for
compression and hoisting. The labor comprises superintendent, crane
operator, loader and winch operator, hopper operator and general laborers.
-14-
-------
Because the larger stations do not require all of these categories in
proportion to the capability the labor mix varies with Q, as does the
average price of labor per man-hour of the labor mix. These basic
figures are shown in Table I for information. However, only the totals,
labor dollars per 312 days and utilities dollars per year, were used in
the computations at the discrete Qg values computed. The estimates and
extentions were plotted on log - log paper and extrapolated to the 3,000
and 6,000 tons per day.
Recognizing the difficulty of achieving a variable labor load in a
municipal type operation, it will be taken that the labor requirement is in-
dependent of U. The utilities cost will be only slightly influenced
by U, here taken as proportional to uO-25.
The results for the transfer stations including the station itself, the
land, the siding and the fencing are shown in the section- of this report
entitled "Computation Method" as Cost Schedule 1.
-15-
-------
TABLE ;
Man-Hours
Mixed Labor Per Day
124 D .160
300 D .103
501 D ,080
1002 D .0563
1500 D .0461
3000 D .0326
6000 D .0230
UTILITIES AND LABOR COSTS
TRANSFER STATIONS
$ Per Man-Hour Labor
Labor Mix $/362
4.10 25
^.10 39
4.10 51
4 00 70
3.92 84
3.62 110
3.29 i4i
Cost
Days
,789
,^99
,271
,3*0
,708
,448
,710
Utilities Cost
$/Year
2,000
2,500
3,000
4,000
4,900
6,900
9,700
-------
B. FREIGHT COSTS
2
When the subject of hauling waste solids was studied in 1961 , it was
observed that railroads would be included to assess ICC Class 13 rates
to this service, but that possibly commodity rates could be negotiated.
In the 1967 investigation of this project1, it was confirmed that the
railroads would tend to assess something of the order of Class 13 rates.
However, for municipal refuse, rail hauling in general seems to have
such an economic advantage over other methods that it appears unlikely
that the railroads would be agreeable to a lower commodity rate.
The general method of constructing a rate table is described in Reference 2
and is shown here for the Eastern rail territory in Table II.
Rate base miles (also termed short-line miles) is the official mileage
established by the ICC between any two railroad points and on which
the quoted rates are based. It is the actual railroad distante by the
shortest combination of connecting lines between the two points. Route-
miles is the actual mileage traveled by the train between the two points.
In many cases, this is the same as the short-line miles, but in some
cases it is more convenient for the railroads to use a longer route in
order to take advantage of a heavily traveled line. Straight-line miles
is the straight-line distance measured on a map between the two points.
Straight-line miles is the datum used in the present study since it is
the statistical geographical parameter which can be easily measured
for any situations. An analysis for a few dozen actual rates showed
that for the nation as a whole, the average ratio of rate base or short-
line miles to straight-line miles was 1.30.
-17-
-------
TABLE II
RATE TABLE FOR EASTERN TERRITORY* GLASS 13
By actual quotation:
Rate Base Miles Straight Line Miles
1309 10^0
999 760
778 560
632 1*10
1*77 280
89 89
By ICC Schedules:
300 253
200 168
100 8k
0 0
Smooth Curve :
0
25
50
75
100
150
200
250
275
275
300
1*00
500
(1961)
Dollars per Ton
15.00
12 ,,50
10,90
9.70
8,30
IK 10
5.8^
I*, 92
3»7l*
l.8l
1.80
2.65
3.20
3.60
3.95
U.15
5»25
5.80
6.10
8.10
8.30
9.55
10,65
-18-
-------
Some judgement must be used in assigning straight-line miles for long
routes in reading the table. For example, if one were concerned with a
New York City - Utica trip, one would probably more closely approximate
the correct rate by taking the sum of the straight-line distance New York
Albany and Albany - Utica rather than the hypotenuse New York - Utica,,
From a plot of the data in Table II there have been taken smooth curve
values shown in the bottom portion of that table. The curve has a break
at 275 miles honoring the ICC schedule below this and the actual
quotation above.
The rail rates actually used in the computations were those shown in
Table IIL These are derived from two schedules, Schedule A and Schedule
B. Schedule A is the ICC and actual quotation Class 13 rates just
discussed. Schedule B was constructed from quotations made by the New
York Central Railroad in particular instances and for particular
distances and tonnages using the unitized train, plus a statement that
for X tons per day, the incremental cost of the next 100 miles would
be Y<^/ton0 This figure, Y, was adjusted upwards by 25% to include
overhead and profit Then it was adjusted to different ton/day figures
by assuming that the incremental cost in dollars on the additional 100
miles changed very little with reasonable changes in tonnage. In other
words, the cost of operating the unitized train was almost the same
regardless of the number of cars. It had been indicated that the railroad
could not afford to undertake a unitized train operation with less than
1,000 tons/day. Nevertheless, this limit was extended downward to
cover 510 tons/day in a unitized train using some judgement to place the
rates at certain mileages corresponding to the mileages estimated for
the other tonnages.
The resulting rates from Schedule B obtained by this method were plotted
on the same sheet with the Schedule A rates, and from these plots the
figures in Table 'III were read off at round number mileages. The two
figures given at 275 miles in the Class 13 rates section represent the
break which occurs in Schedule A at about that distance, below that
distance being from ICC schedules and above that distance from actual
quotations for long distance service on solid waste in regular trains
It is re-emphasized here that these possible rates are entirely the
construction of the author based on the indicated information and do
not represent figures which can be compared with actual quotations that
individual railroads may give. Various railroads may have different
cost structures than those upon which Table III is based, and furthermore,
as has been explained rail rates between particular points are highly
dependent upon the individual characteristics of the run, and are
subject to arbitrary discontinuities.
Furthermore, rate making for unitized train service on refuse conveyance
is a new art on which little experience is available. As experience is
gained in the future such rates as assigned here may either increase or
decrease. The rates in Table III are based on design capability, tons/day,
-19-
-------
TABLE III
POSSIBLE RAIL FREIGHT RATES FOR CONTAINERIZED SOLID WASTE HAULING
$/ton handled
UNIT TRAIN RATES
Schedule B
Tons /Day
Miles
10
i 50
N>
O
20
100
150
200
250
275
300
400
500
3000
6000
1.50
1.95
2.15
2.35
2.65
2,95
3.30
3 = 60
4,20
4.90
1500
1.50
2.05
2.25
2.65
3.25
3.90
4.50
5.10
6.25
7.75
990 510
1.50 1.80
2.10 2.55
2.35 3.00
2.90 4.15
3.80 5.95
4.20 7.65
5.65 9.50
6.15
8.50
10.65
510
3.95
4.15
5.25
5.80
6.10, 8.10
8.30
9.55
10.65
CLASS 13 RATES
Schedule A
300
2.10
3.20
3.50
3.95
4.15
5.25
5.80
6.10, 8.10
8.30
9.55
10.65
124
2.10
3.20
3.50
3.95
4.15
5.25
5.80
6.10, 8.10
8.30
9.55
10.65
-------
on the grounds that the railroad has to have the cars, locomotives
and crew available to meet the peak day regardless of the actual
tonnage hauled. After the railroads have gained some operating
experience with this as a regular feature, they may find that the rates
can "be reduced to reflect some of the savings, whatever their magnitude
may "be, brought about by hauling an average tonnage which is of the
order of one half the design tonnage, taken throughout an entire year.
It should also be mentioned that if a community seeks to use a single-car
conveyance system on a regular way train, it must have a situation in
which there is a regular way train leaving each day at the proper time,
that is, in the late afternoon, and another regular train returning from
the UDR facility at some proper time during the night Furthermore, the
interval between the arrival and the departure at the UDR facility must
be at least equal to the full turn-around time required for the unloading-
loading operation on the containers
1. TURN-AROUND PRICE
An uncertain factor in the total price charged by the railroad is
the turn-around time,, This is the time during which the engine and
train crew are waiting at the UDR facility for the unloading and
loading process to be completed. This turn-around time varies from
situation to situation depending on the optimization of the crane-
container system. A certain amount of this turn-around time is
presumably contained in the freight rates already developed, but
the railroads would probably have to increase these rates in
situations where the turn-around time becomes excessive Accordingly,
this turn-around time is costed as a separate item.
An 89 foot flat car will take three 27 foot 30 ton containers and
accordingly, the number of cars in a unit train is:
c =i-
A single 2,500 HP diesel unit will handle 50 cars, and one additional
will be required for each fraction of 50 beyond this. The number
of diesel units involved therefore is:
The full turn-around time is:
2 Bt.
-21-
-------
While idling a 2,500 HP diesel will consume 7-5 gallons of fuel
per hour^ and the average price bid by railroads for diesel fuel
in 1965 was 9.37 c/gal.5
The working life of such a diesel unit is 15 years with an average
of 335 days per year operating, 30 days "being taken out for regular
and special maintenance. The capital recovery factor will be taken
for 15 years at 6%, insurance at 3%, taxes at 1% and maintenance at
1%, taken when idling. The total fixed cost factor is 0.1530
fraction per year. This computes to a fixed cost of ^.758 $/hr.
per unit, or with the fuel 5-^6l $/hr. There is a five-man crew
on the train irrespective of the number of diesel units and this
becomes 5 P-, dollars per hour per train for labor.
To the total of the fixed cost and labor cost for turn-around time,
there is added 25% for general overhead and profit to yield a price
for turn-around of:
= 1,25 [5.U61 ( (Tel +1) + 5 PJ (2 Bix_312)
II en 1 -VT
Year
Ton " [5.1*61 ( Ic + 1) + 5 P, ] BT
Nk
2, SWITCHING PRICE
When the conveyance system comprises a single car or a group of
single cars hauled on a regular way train a charge will be incurred
for switching the car on to and off of the train. There will be
four such switching events, one to switch the car on to the train at
the transfer station, one to switch it off the train at the UDR
facility, one to switch it on to the train returning the empty,
and one to switch it off of the train at the transfer station. A
normal charge for this switching operation accomplished in a way
train having a switching crew is $7- 50/switch. However, this can
vary considerably with the switching circumstances. For example,
if an inter-line switch should be involved in a large city, the
cost might be as much as $90/switch. However, assuming that the
situations covered here involve transfers between an origin point
and a destination point on a single rail line, the unit price will
be taken as $30 - (k- x $7-50) per car.
The switching price will be incurred only for cars actually trans-
ferred; that is, it will be approximately proportional to U. On
any particular day characterized by a tonnage Q and a number of
cars (B/3)*, the switching price will be:
Switching price, $/ton = 301-
~u
or Switching price, $/ton = 30 /QU\
QU (
Q
t
3t/
-22-
-------
With 30 ton containers and without the integer restrictions, this
quantity equals 0.333 $/ton for any tonnage. However, with the
integer restrictions the quantity varies with Q and also with U,
where U indicates the utilization factor for a particular day.
Table IV shows the switching price at the various Q values and at
U = 0.3, 0.5 and 1.0.
TABLE I.V
SWITCHING PRICE, $/TON HANDLED
[at $7.50 per switch, 30 ton containers)
120
300
510
990
1500
3000
6000
0.3
.833
.333
.382
.333
.333
.333
0.5
.500
.1*00
.353
.361*
.360
.31*0
.3^0
1.0
,500
,1*00
.353
.333
.31*0
.31*0
.335
Average
of 3
.611
.366
.367
.338
.336
If in achieving an overall annual utilization factor, U = 0.5 the
U on each day were 0.5, then the switching prices would be as
shown in the 0.5 column.
However, an annual U of 0.5 is composed of individual days having
various daily utilization factors some probably as low as 0.3 and
others possible as high as 1.0. The actual overall average
switching price per ton handled depends upon the frequency distri-
bution of daily tonnage and can only be accurately obtained by
integrating such a relation. However, this relation is not known,
was not explored in this study and will be approximated by caking
the integral as equal to the average of the three U values in the
table.
C. UTILIZATION FACTOR
No general study on utilization factors for refuse systems was available
so the choice of a typical parameter value for U was made from informa-
tion made available in Reference 1. The utilization factor involved
is the daily utilization factor:
U = average daily genration throughout the year, tons/day = Q^
design capability, tons/day Q
The design capability,
in the year.
must be such as to accommodate the peak day
-23-
-------
From the available information, for Westchester County, 196^ - 1965, the
highest days occurred in June and July, several days having ratios Q
Q
such as 1.72, 2.24, 1.77, 2.13, etc. If the installation is designed to
handle peak days of the order of 2.0 x the average generation, then over
the entire year it will operate at a utilization factor U = 0.50. This
figure applies to a system designed to handle this year's load and
operated under this year's conditions.
Subject to the conclusions of the overall project if it "be assumed that
the installation is set up now with a capability to handle the load ten
years from now and the increase in waste generation over that period is
30%, then that system designed for ten years hence would in its first
year be operating at U = 0.38, in its tenth year at 0.50 and over the
ten year period at something a little less than O.HU.
-24-
-------
SECTION IV
COMPUTATION METHOD
On the following pages, there is reproduced a form sheet for computing rail
haul costs according to the system herein developed, and to be used in
conjunction with the cost schedules, numbered 1 to 8, which provide the
information on the various cost components in terms of the variable para-
meters Q, U, D. The form as a computing program is self-explanatory. It
includes adjustments for the price of land, and for utilization factors
different from the standard 0.5.
One example is worked out in Table V so that the reader may follow the
procedure step-by-step.
-25-
-------
TABLE V
SAMPLE CALCULATION
FORM SHEET FOR COMPUTING RAIL HAUL COSTS
Variable parameters given Line No_.
Capability £, tons/day* 3,000 (2)
Utilization factor U, fraction '4 ,~t
Distance D, miles -^QQ *,,
Travel velocity V, miles/hour 3Q ,^
Land price PL, $/acre 20,000 (6)
Derived variable parameter DV, hours 3 333 rj\
Transfer facility. Read Cost Schedule 1 @ Q and PL=1000 >592 (9)
PL adjustment: PL -1000 x (9) .019 x .592 ]007 ^J
106
Adjusted for PL: (9) + (10)_ .599 (12)
Adjusted for U: (12) x 0.5/U .750 (13)
Containers. Rea.d Cost Schedule 2 @ Q and D/V .758 (14)
Adjusted for U: (14) x 0.5/U .945 (15)
SUB-TOTAL: COMMUNITY'S COSTS (13) + (15) 1.695 (16)
Cranes. Labor and supplies. Read Cost Schedule 3 .022 (17)
Adjust for non-integer: (17) x fl + /Q\* - (£1 .022 (18)
Fixed. Read. Cost Schedule_4 @ Q and D/V .063 (19)
Adjust for U: (19) x 0.5/U .079 (20)
UDR siding._ Read Cost Schedule 5 @ Q .017 (21)
Adjust for U (21) x 0.5/U .021 (22)
SUB-TOTAL: UDR CONTRACTOR PRICE: (18) + (20) + (22) .122 (23)
Freight. Freight rate price. Read cost schedule 6 @ Q + D 2.350 (24)
Turn-around (unitized only) Read cost schedule 7 @ Q + D/V .127 (25)
Adjusted for U: (25) x 0.5/U .159 (26)
Switching (waytrain only) Read cost schedule 8 @ Q (27)
SUB-TOTAL: RAILROAD PRICE: (24) + (26) or (27) 2.509 (28)
TOTAL RAIL HAUL COST (16) + (23) + (28) 4.326 (30)
*For values of Q not given in the schedules obtain appropriate approximate values
by interpolating between tabulated values.
-26-
-------
COST SCHEDULE 1
TRANSFER FACILITY COST
Variable parameters controlling: QUP
j_j
For use where U = 0.5 and P = 1,000 and 1^0,000
Q
12^
300
510
990
1500
3000
6000
PT = 1,000
Li
3.910
1.077
1.VT7
989
.817
592
.^57
PT = U0,000
J_J
U.170
2.158
1.5^0
1.060
.85^
.618
.176
To adjust approximately for land prices, subtract from the above H0,000
figures :
U0,000 -PT 4. 4, 4.T, 4. -u -, 4. ,, i
___ _ L percent of the tabulated value
10,000
or add to the 1,000 figures:
_L _ ' percent of the tabulated value
10,000
Example: For PT = 20,000 at 510 tons per day:
J_J
0
- .031 = 1.50U $/ton
The correct computed value for P = 20,000 is 1.508 dollars per ton.
Li
To adjust quite accurately for U, multiply the tabulated costs by 0.5/U,
Example: Q = 510 , P = 1|0,000, U = .hO and U = .60
lj
^-y- = 1.925; the correct computed value is 1.922
U T-
^-r- = 1.283; the correct computed value is 1.
-27-
-------
COST SCHEDULE 2
CONTAINER COST
Variable parameters controlling: Q, U, D expressed as Q, U, D/V
Values at U = 0.5, $/ton handled
Q = 120 tons/day
D/V Range 0 to 8.367 to 20.367 to 32.367 to
8.367 20.367 22.367 44.367
Cost, $/Ton 0.758 1.062 1.365 1.668
Q = 300 tons/day
D/V Range 0 to 8.167 to 20.167 to
8.167 20.167 32.167
Cost, $/Ton .758 1.062 1.668
Q = 510 tons/day
D/V Range 0 to 7.934 to 19.934 to 31.934 to
7.934 19.934 31.934 42.934
Cost, $/Ton .767 1.067 1.374 1.677
0 - 990
D/V Range
0 to
7.950
7.950 to
19.950
19.950 to
31.950
Cost, $/Ton .763 1.066 1.369
Q = 1.500 tons/day
D/V Range 0 to 7.945 to 19.945 to
7.945 19.945 31.945
Cost, $/Ton .758 1.062 1.366
-28-
-------
COST SCHEDULE 2. Cont.
Q = 3.000 tons/day
0 = 6,000 tons/day
D/V Range
Cost, $/Ton
0 to
7.834
.758
7.834 to
19.834
1.061
19.834 to
31.834
1.364
Precise values of $/ton at other U's: Multiply above by 0.5
U
-29-
-------
COST SCHEDULE. 3
CRAKE PRICE
Crane Price, Labor and Supplies
Q *
Variable parameters controlling: Q but only via B, i.e. ( ) . For values
of Q such that Q/t is an integer crane labor and supplies is independent of
Q and has the value 0.022 $/ton. For other values of Q it is:
0.022 (1 + (V - & , $/ton
"G u
a term which varies linearly with Q between 0.022 and O.O^U.
-30-
-------
COST SCHEDULE 4
CRANE PRICE. FIXED
Variable parameters controlling: Q, U, D expressed as: Q, U, D/V
Values at U = 0.5
D/V Range
Crane Price, Handled $/Ton
Q = 120
0 to co
1.581
Q = 300
0 to oo
0.632
Q = 510
0 to oo
.372
Q r.
D/V Range
Crane Price
0 to
7.401
.192
7.401 to
7.950
.383
7.950 to
19.401
.192
19.401 to
19.950
.383
19.950 to
31.401
.192
31.401 to
31.950
.383
Q = 1,500
D/V Range
0 to
6.835
6.835 to
7.667
7.667 to
18.835
18.835 to
19.667
19.667 to
19.945
19.945 to
30.835
Crane Price
.127
.254
.380
.254
.380
.127
Q = 3,000
D/V Range
0 to
5.170
5.170 to
6.835
6.835 to
7.390
7.390 to
7.667
7.667 to
7.834
7.834 to
17.170
17.170 to
18.835
18.835 to
19.390
19.390 to
19.667
Crane Price
.063
.126
.190
.253 .316 .063
repetitive at D/V + 12
.126
.190
.253
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COST SCHEDULE 4, Cont.
Q = 6.000
D/V Range 0 to 1.840 to 5.170 to 6.280 to 6.835 to 7.168 to 7.390 to 7.549 to 7.668 to 7.760 to 7.834 to 13.840 to
1.840 5.170 6.280 6.835 7.168 7.390 7.549 7.668 7.760 7.834 13.840 17.170
Crane Price .032 .063 .095 .126 .158 .190 .221 .253 .285 .316 .032 .063
etc. repetitive at D/V + 12
Precise values of crane price, handled for other U's: Multiply above $/ton by 0.5 .
U
i
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NJ
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COST SCHEDULE 5
UDR SIDING PRICE
(track only, not land)
Variable parameters controlling: Q, U
Values for U = 0.5
.Q $/ton
120 .02h
300 .020
510 .018
990 .017
1500 .017
3000 .017
6000 .017
Precise values for other U's: multiply at>ove Toy 0. 5
U
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COST SCHEDULE 6
FREIGHT RATE PRICE
Variable Parameters
D
10
50
70
100
150
200
250
275
275
300
1*00
500
Q 120
2.10
3.20
3-50
3-95
U.15
5-25
5.80
6.10
8.10
8.30
9.55
10.65
Controlling: Q, D
$/TON HANDLED
SINGLE CAR
300
2,10
3.20
3.50
3.95
^. 15
5-25
5.80
6.10
8.10
8.30
9-55
10.65
UNITIZED TRAIN
510 510 990
1.80 1.50
2.55 2.10
3.00 2.35
3.95 ^. 15 2.90
it. 15 5-95 3.80
5.25 7.65 i*.70
5.80 9-50 5.65
6.10
8.10
8.30 6.15
9-55 8.50
10.65 10.65
1500
1.50
2.05
2.25
2.65
3.25
3.90
it. 50
5.10
6.25
7-75
3000
6000
1.50
1.95
2.15
2.35
2.65
2.95
3.30
3.60
it. 20
it. 90
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I
Co
Ln
I
COST SCHEDULE 7
TURN-AROUND PRICE
Unitized Train Only
Variable parameters controlling: Q, U, D expressed as Q, U, D/V
Values at U = 0.5.
Pattern between vertical lines repetitive by adding 12 hours to each listed D/V value.
Q = 120 Q = 300 (I =510
D/V Range 0 to °° 0 to » 0 to °°
Price, $/Ton 0.127 0.127 0.127
Q = 990
D/V Range 0 to 7.401 to 7.950 to 19.401 to
7.401 7.950 19.401 19.950
Price, $/Ton .127 ,064 .127 .064
Q = 1^500
D/V Range 0 to 6.835 to 7.667 to 7.945 to 18.835 to 19.667 to
6.835 7.667 7.945 18,835 19.667 19.945
Price, $/Ton .127 .064 .042 .127 .064 .042
Q = 3,000
D/V Range 0 to 5.170 to 6.835 to 7.390 to 7.667 to 7.834 to 17.170 to 18.835 to
5-170 6.835 7.390 7.667 7.834 17.170 18.835 19.390
Price, $/Ton .127 .064 .042 .032 .025 .127 .064 .042
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COST SCHEDULE 7, Cont.
Q = 6.000
D/V Range 0 to 1.840 to 5.170 to 6.280 to 6.835 to 7.168 to 7.390 to 7.549 to 7.668 to 7.760 to 7.834 to 13.840to
1.840 5.170 6.280 6.835 7.168 7.390 7.549 7.668 7.760 7.834 13.840 17.170
Price, $/Ton .158 .079 .053 .040 .032 .026 .023 .020 .018 .016 .158 .079
Precise values of $/ton for other U's: Multiply above by 0.5 .
U
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ON
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COST SCHEDULE 8
SWITCHING PRICE
.applicable to way train service, not unitized train]
Variable parameters controlling: Q and frequency distribution of daily
utilization factor, the latter unknown
and approximated here.
$/ton
120 .611
300 .hhk
510 .366
990 .367
1500 . 3^
3000 .338
6000 .336
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SECTION V
SELECTED EXEMPLARY RESULTS
The computing form and cost schedules have "been used to compute a limited
number of complete situations at varying capabilities and at two distances,
100 and 50 miles, at a utilization factor of 0.5. The results thereof are
shown in Table VI and plotted in Figure 2.
Referring to the figure, it is seen that the unit cost per ton handled
decreases with capability. The economic breakpoint between way train and
unitized train occurs in the neighborhood of ^00 tons/day capability, being
a little higher at 100 miles than it is at 50 miles.
The unit cost is definitely sub-proportional to the distance. For example,
at 1,000 tons/day capability (500 tons/day average conveyed) the cost of
conveying a hundred miles is only 19% more than the cost of conveying 50
miles.
As to the disbursement of the total costs incurred, in most situations the
larger share becomes revenue to the railroad, next in order being the
community's own expenses for containers and transfer stations, and lowest
in order the contractor revenue for the unloading operation at the UDR
facility.
The computation method and the basic data of this report may be used for a
variety of comparisons. These include the assessment of the sensitivity
of costs to various values of the fixed parameters for example labor prices,
as well as of the situation parameters, for example utilization factor.
Also such computations may be used to fix the locus in distance and
capability of the economic breakpoint between way trains and unitized trains.
Because this study is preliminary in nature, the opportunity is not given
to explore these various relationships here.
However, one exploration will be made because it has been left unresolved
from an earlier section. There it was indicated that the cost was
insensitive to price of land even to very high land prices of the order
of $^0,000 per acre, and therefore, the price of land was not an important
determinant of the cost of rail hauling. This fact is demonstrated in the
last rows of Table VL For 120 tons/day the land cost is 6.6<£ out of a
total cost of over $10,000 land at $20,000 per acre, therefore, contributing
0.65% to the total cost. At the other end of the scale, at 6,000 tons/day
land cost is 1<£ out of a total cost of $3-50 to $H.70 per ton, a contribution
of 0.29% at the most to the cost of rail haul.
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TABLE VI
RESULTS OF EXEMPLARY COST COMPUTATIONS
Q. ton/day_
120
300
510
990
1500 3000
Total
6000
$/Ton @ U = 0.5, D = 100 miles, V = 30 MPH, PT = 20,000 $/acre
J_J
Community It. 7^2 2.8?^ 2.272 1.771 1-590 1.36l 1.223
Contractor 1.627 .67^ .Ul2 .231 .166 .102 .071
Railroad ^.561 H.391* H.277 3.027 2.777 2.^77 2.1+29
10.930 7-9^2 6.961 5-029 ii.533 3.9^0* 3.723
$/Ton @U=0.5,D=50 miles, V = 30 MPH, P* = 20,000 $/acre
L
Community U.7^2 2.87*1 2.272 1.771 1-590 1.36l 1.223
Contractor 1.627 .67^ .^12 .231 . l66 .102 .QUO
Railroad 3.811 3.6W 2.677 2.227 2.177 2.077 2.256
Total
10.180 7-192 5.361 U.229 3.933 3-5^0 3.519
Land Cost
Land % of Total
0.066
O.i
0.010
0.29$
*Compare this case in the exemplary computation, Table V
@ U = O.h where the cost is H.326 $/ton
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CALCULATED COSTS OF CONVEYING
SOLID WASTES BY RAIL
zu
15
-O
=1 10
-S 9
I 8
S 6
o
u
5
4
3
5
1C
::xx
f>r*~^ A"-
~^ ..
// v-o^ «**//._
^ Way Train 4 ^~L
C^
^
f^- S>n^^?
^J:
'^/.. "^^ X"-..
-
, , 1
0 150 500 1500 30C
AVERAGE CONVEYED, QU, tons/day
i i i
0 300 1000 3000 601
CAPABILITY, Q, tons/day
Figure 2
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SECTION VI
REFERENCES
1. New York Central Railroad, Private Communication, 1967.
2. United States Public Health Service. Ultimate Disposal_of Advanced
Treatment Waste. Part I, Injection; Part II, Placement in
Underground Cavities; Part III, Spreading. Publication No. 999-WP-10,
Washington, May 1964.
3. Southern Pacific Company, San Antonio, Texas, Private Communication,
June 1967-
4. Association of American Railroads. Statistics of Railroads of Class 1 in
the United States Years 1955 to 1965. AAR Washington, Sept. 1966.
-41-
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PART 9
MUNICIPAL BUYING PRACTICES
Prepared by
Leo J. Cohan
Product Supervisor
Industrial Sales & Marketing Department
November 1, 1967
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MUNICIPAL 'BUYING PRACTICES
Improved performance of incinerators and other types of waste reduction
equipment is severely limited by the present practices used by municipalities
in buying incinerator components instead of total systems. The following
material describes the problem in more detail and recommends a possible
solution.
The following list of different buying influences indicates the complexity
of marketing waste reduction facilities to municipalities:
A. Turnkey
1. Municipality synonymous with regional refuse disposal authority.
Town Engineer
Town Mayor or City Manager
Town Council
2. Consulting Engineer
3. General public (who must accept the concept that the specific
waste reduction process is desirable).
B. Integrated Systems (Burning System)
1. Architect - Engineer
2. General Contractor
3. Municipality
4. Consulting Engineer
C. Equipment Components (Stoker, Fans, Furnaces, etc.)
1. Sub-Contractor (incinerator)
2. General Contractor
3. Architect - Engineer
4. Consulting Engineer
D- Service Contract
1. Municipality
Town Engineer
Town Mayor
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City Manager or Politician
2. Consulting Engineer
The turnkey approach which has been used in the past provides one supplier
to perform the role of general contractor, incinerator contractor, equip-
ment supplier, manufacturer of certain proprietary equipment, and guarantor
of system performance. This supplier will sub-contract all work he cannot
handle.
The integrated system approach provides a standard burning system of
tested design with quaranteed performance and quaranteed price with
estimated or demonstrated operating costs. This would require more than a
straight performance specification because bids on the system would be
accepted on an evaluated basis.
Equipment components provide for the sale of proprietary items supplied to
detailed specifications.
The present concept of supplying equipment to detailed specifications
precludes the very important item of system engineering. Incineration is
a process and as such is a series of dependent variables. The performance
of one component is affected by the performance of others. Adequate hard-
ware may be selected and integrated into an incompatible system. This
results in poorly designed and performing plants. The lack of emphasis or
attention to a properly worded performance specification has been apparent
in the past and a complete review of this field is required. Trends in
procurement legislation and practice will encourage objective performance
specifications.
A Federal procurement officer has made this observation:
"The tightness of a specification must be justifiable, and should
be in the form of performance requirements rather than component
descriptions ..."
"The modern concept of specification writing in procurement differs
completely from the patent-type specification. The invitation bid
must state clearly and concisely what is required. It must provide
a basis for rejecting bids on items not meeting the needs of the
service. It must provide a necessary 'hammer' to enforce per-
formance under the contract, which includes guarantees, service
policies, maintenance facilities. Performance requirements,
properly stated, will control this more effectively than penalty
clauses or component details." (R. G. Wessells, American City,
April 1961)
The performance guarantees, demonstrated costs, and system integration
contemplated in a burning system seem ideally suited for the future trends.
If system analysis is to be advocated as the means by which we are to solve
our solid waste disposal problems, then it is logical to infer that the
system approach should also be used when contemplating specific pieces of
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waste reduction equipment. By firmly fixing the responsibility for design
and selection of the system with one group, the probability of meeting
performance goals is increased. The performance specification, properly
evaluated, which involves a system concept offers municipalities a
combination of benefits that are not only needed, but should have a high
probability of being widely used.
It is recognized that considerable resistance to standardized burning
systems can be initially expected from many engineers. Naturally, options
among non-proprietary components must be considered in line with objective
requirements of optimum technical performance.
Although refuse incineration technology needs further development, it has
reached a state where considerable standardization of burning systems is
feasible. Standard burning system modules could be developed now without
much risk that they would be quickly obsoleted by a basic new advance.
Standardization is compatible with technological progress. A basic burning
system could be designed to accommodate future improvements in stokers,
air pollution control systems and equipment, instrumentation and control
systems, etc.
Standardization is compatible with adaptability. The particular needs and
preferences of most communities can be met through options to the basic
burning system modules, for example, needs and preferences with respect to
total plant capacity, number of furnaces per plant, degree of air pollution
control, degree of automation, type of stack (stub or regular), etc.
Standardization is compatible with future improvement of individual plants.
Retrofitting or replacement can be a design consideration in both the basic
modules and the advances that are achieved in stokers, air pollution control
equipment, etc.
Options can be compatible with profitability serving a major share of the
market. The number and character of the options should be kept within
limits that will prevent dissipation of the technical and economic benefits
and the competitive advantage and profitability afforded by standardization
In design, components, and construction.
Buildings can benefit from standardization of basic layout and sub-systems.
Compared with a custom-designed building, a standardized building would
offer lower first cost, usually lower maintenance costs, and assure con-
venience and efficiency of layout, facilities, and sub-systems. A reasonable
number of options could adapt the building to the individual requirements
of most municipalities.
A standardized plant built from options to the municipality's
individual requirements would offer a decisive combination of advantages
over a custom-designed plant. There would include guaranteed burning
performance, system integration, and operating characteristics at lower net
ultimate cost to the community. Standardization makes it possible to
guarantee initial price, burning performance and pollution control, and to
reliably demonstrate total annual operating and maintenance costs.
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Economic and technical advantages of standardized modular plants will
make it unnecessary and wasteful to custom-engineer each of the 100
incinerator plants that will be erected in the next five to seven years.
Present attitudes toward the idea of standardized plants, designed and
supplied by manufacturers, are largely negative. It is widely believed
that this practice in the past from the 1920's to the 1950's was
mainly responsible for holding back the development of incineration
technology. Progress in recent years is attributed to the growing capa-
bility of city engineers, and consulting architect engineers, and their
initiative in taking responsibility for the basic design of individual
incinerator plants.
While there are some negative attitudes toward standardized systems, they
have persisted largely because no company with the requisite technical
capability, financial resources, and stature has undertaken to serve the
municipal market's need for standardization combined with technological
progress. Some city engineers and consulting firms have an understandable
preference for custom-engineered plants.
The introduction of standardized systems, even by a highly regarded company,
would encounter some initial resistance and suspicion and a "thousand
reasons" why it won't work.
Resistance to standardized modular plants can be overcome if a company
earns and gains acceptance of the following four propositions:
1. The company's adaptable standardized plants are decisively
advantageous to the municipality compared with custom-designed
plants.
2. The company is capable of making substantial contributions to
incineration technology, and will undertake a program to do so.
3. The company will incorporate proven technological advances in its
standardized modules and, where feasible, contract to incorporate
improvements in modules that are already in service.
4. The company's development program will seek not only improvements
to its existing standard systems, but also fundamental advances
that could require basic redesign of those systems.
The market acknowledges that there has been considerable progress in
incineration technology. But it expects that there will be more. The
market will not "buy" the idea of standardized systems until it is convinced
that standardization will be utilized not to impede progress, but to make
progress available in the most economical form.
The four propositions above must be demonstrated to be believed by buying
influences. Many will simply state they "haven't seen it yet".
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In their role as independent, outside experts ostensibly free from
biasing relationships with municipalities or equipment manufacturers
consulting and architect engineers perform functions that are almost
universally valued by municipal buying influences. High among these
functions is the protective one of providing municipal officials with
outside rebuttal of actual criticism, or prevention of potential criticism
from the public or other officials. An equipment manufacturer can seldom
perform this protective function, in the face of presumed economic interest.
The independent consultant also helps enlist public support and gain
required approvals from state agencies.
The consultants protective role, together with the valuable engineering
work done by capable consultants, indicates that they are an extremely
active and influential force in this market. The most prevailing attitude
is that projects like incinerator plants require a great deal of survey
work, detailed engineering, evaluation, and coordination. These have to
be done by somebody, and it should be done by qualified consultants who
can also lend protective and support-enlisting authority to the project.
Consulting and architect-engineers are essential professional allies of
both the municipality and the equipment manufacturers. To regard them
otherwise is to attack their profession and the judgment of those who value
the functions they perform, including their participation in the specification
for bids and awarding of contracts.
Some consultants would be opposed, initially, to the idea of standardized
plants. But they could be convinced that it is professionally untenable
to oppose such plants, once their advantages to municipalities are
demonstrated by actual installations and operating results.
Major engineered systems such as incinerator plants are less subject to
questionable buying practices than are products like parking meters and
sewer pipe.
Modern incinerator plants have many characteristics of electric generating
stations, and are increasingly taking on the character of municipally-owned
utilities and, potentially, of regulated investor-owned utilities.
Socio-economic factors such as higher standard of living, urban renewal,
higher literacy, etc. will focus attention on the incineration process.
Federal and state legislation will force sound system practices.
Finally, leadership itself could be a factor increasing the proportion of
sound incinerator business. This would come about not as a separate project,
but by conducting the business in the mutual best interests of private
business and the communities it would be serving.
In summary, certain legal requirements may restrict purchasing practices,
however, cognizant committees should advocate modifications and changes in
legislation where they are not compatible with the best technical interest
of the public.
Jn the integrated burning system, the responsibility for the performance
°i the above factors must ultimately rest with one major guarantor.
AU. S. GOVERNMENT PRINTING OFFICE : 1969 O - 352-813
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