Environmental Protection Technology Series
EVALUATION OF
SOLID WASTE RECOVERY SYSTEM
Part i • Summary of Environmental
Emissions: Equipment, Facilities, and
Economic Evaluations
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
I. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-'
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-77-205
November 1977
EVALUATION OF THE AMES SOLID WASTE RECOVERY SYSTEM
Part I - Summary of Environmental Emissions:
Equipment, Facilities, and
Economic Evaluations
by
J. C. Even, S. K. Adams, P. Gheresus,
A. W. Joensen, and J. L. Hall
Iowa State University
Ames, Iowa 50011
D. E. Fiscus and C. A. Romine
Midwest Research Institute
Kansas City, Missouri 64110
Grant No. R803903010
Project Officer
Carlton C. Wiles
Solid and Hazardous Waste Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement or recommendation for use.
ii
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FOREWORD
The Environmental Protection Agency was created because of increasing public
and government concern about the dangers of pollution to the health and welfare
of the American people. Noxious air, foul water, and spoiled land are tragic
testimony to the deterioration of our natural environment. The complexity of
that environment and the interplay between its components require a concentrated
and integrated attack on the problem.
Research and development is that necessary first step in problem solution
and it involves defining the problem, measuring its impact, and searching for
solutions. The Municipal Environmental Research Laboratory develops new and im-
proved technology and systems for the prevention, treatment, and management of
wastewater and solid and hazardous waste pollutant discharges from municipal and
community sources, for the preservation and treatment of public drinking water
supplies, and to minimize the adverse economic, social, health, and aesthetic
effects of pollution. This publication is one of the products of that research,
a most vital communications link between the researcher and the user community.
The combination of the growing unacceptability of traditional methods of
waste disposal along with the need to conserve the nation's resources has
spurred efforts to exploit solid waste. The current energy shortage helped
stimulate a further awareness that the high percentage of combustible material
in solid waste represents an energy resource.
On August 30, 1975, the first continuous full-scale, solid waste recovery
system for the processing and burning of municipal solid waste as a supplementary
fuel for power generation commenced operation in the City of Ames, Iowa. This
plant was designed using experience gained from the operation of the Environ-
mental Protection Agency - City of St. Louis - Union Electric Company refuse
demonstration plant.
This report provides the cumulative results of the Ames, Iowa refuse proces-
sing plant experience during its first full year of operation (1976). It provides
basic data on the economics of operating the plant, the operating experience, and
the characterization of refuse derived fuel, and will add to the knowledge required
for future successful utilization of the resources contained in solid waste.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
iii
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ABSTRACT
This report describes the results of the following tests and evaluations
of the Ames, Iowa, refuse processing plant during the year 1976: characteri-
zation of the refuse derived fuel (RDF) produced; equipment and plant perfor-
mance evaluations; an analysis of plant maintenance and manpower requirements;
and an analysis of plant operating costs. Also included is a brief summary
of the'boiler environmental emissions and boiler performance when mixtures of
coal and RDF are burned. Complete discussion of the boiler emissions and per-
formance will be available in separate reports. During the year the plant
processed 37,136 Mg of municipal solid waste. Average as received heating value
of the RDF produced was 13,050 kj/kg at 23.0% moisture and 17.4% ash. The net
cost of operating the refuse processing plant after credits were given for the
RDF, recovered metals and dump fees was $18.90/Mg of municipal solid waste
received. The economic model of the plant showed that a volume increase is
the most attractive method of reducing the net cost.
This report was submitted in fulfillment of Grant No. R803903010 by the
City of Ames under the sponsorship of the U.S. Environmental Protection Agency.
Research studies were conducted by Iowa State University and Midwest Research
Institute in cooperation with the Ames Laboratory, Energy, Research, and Devel-
opment Administration. This report covers the period from February 1976 to
February 1977.
iv
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CONTENTS
Foreword ill
Abstract lv
Figures vii
Tables ix
Acknowledgments .................. ..... xiv
1• Summary...... ... ...... 1
2. Introduction ................. 3
3. Summary of Environmental Emissions and Performance of the
Stoker-Fired Boilers ... 5
Power plant description ................. 5
Experimental design, sampling locations, and analytical
methodology ..... ............ 5
Boiler performance. ................... 13
Environmental emissions ................. 13
4. Refuse Processing Plant Monthly Production .. 28
5. Characterization of RDF. 31
Moisture and heating value of daily samples of RDF taken
by the City of Ames during the year 1976. ....... 31
RDF bulk density, proximate and ultimate analysis,
screen size, and ash chemical analysis and fusion
temperature . . . .............. 35
6. Refuse Processing Plant Equipment and Facility Evaluations . . 53
Refuse processing plant activity. ............ 55
Raw refuse received ................... 72
Processing plant labor 75
Processing and downtime ................. 80
Electric power utilization. ...............
Refuse derived fuel (RDF) conveying system and storage
bin 86
Other plant evaluations 89
7. Economic Evaluation. .......... ..... 95
Capital investment. .. ............ 96
Economic operating experience 99
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CONTENTS (continued)
Appendices
A. Monthly production-refuse processing plant. ••••••••••••
B. Daily values of RDF moisture content and heating value Ill
C. Tabulation of information on equipment and facilities evaluation. . 116
D. Capital expenditures Ames, Iowa, solid waste recovery system. ... 196
vi
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FIGURES
Number
1 Boiler units nos. 5 and 6 sampling locations 7
2 Percent excess air as a function of RDF heat input. ....... 14
3 Particulate emissions as a function of RDF heat input ...... 15
4 Particulate collector efficiency as a function of RDF heat input. 16
5 Cumulative particle size distribution of stack emissions as a
function of RDF heat input. .................. 17
6 NOX stack emissions as a function of RDF heat input 18
7 Sulfur stack emissions as a function of RDF heat input 19
8 Chloride stack emissions as a function of RDF heat input. .... 20
9 Formaldehyde stack emissions as a function of RDF heat input. . . 21
10 Cyanide stack emissions as a function of RDF heat input ..... 22
11 Phosphate stack emissions as a function of RDF heat input .... 23
12 Monthly amount of raw refuse received .............. 29
13 RDF and Fe-metal as percent of raw refuse 30
14 Daily values of RDF moisture and heating value. 33
15 Monthly average value of RDF moisture and heating value ..... 34
16 Procedure for determination of bulk density 37
17 Heating value of refuse derived fuel (RDF) versus moisture and
ash content for daily samples ...... ...... 52
18 Refuse processing plant flow diagram, City of Ames, Iowa 54
vii
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FIGURES (continued)
Number Page
19 Air separation chamber. 62
20 Modification to air separation chamber • 63
21 Air density separator ... ............ 65
22 Air density separator feeder modification •••••••••••• 66
23 Number of private vehicles delivering raw refuse to the refuse
processing plant versus day of the week ••••»••••••• 74
24 Total .direct man-hours worked in refuse processing plant 79
25 Dimensions of shredder hammers. 90
viii
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TABLES
Number
1 Characteristics of Ames Municipal Power Plant Stoker-Fired
Steam Generators. ...................... 6
2 Summary of Experimental Design. ................ 8
3 Test Summary of Environmental Sampling ..•••• 9
4 Summary of Sampling and Analytical Procedures for Boiler
Environmental Emissions ................... 11
5 Organic Compounds in Stack Emissions 24
6 Calculated Trace Elements in Uncontrolled Particulates. .... 25
7 Comparison of Daily Samples of RDF Taken over 1 Year Period,
St. Louis - September 1974 Through September 1975, Ames -
January Through December 1976 ... ........ 36
8 Sampling Schedule Random Sampling of RDF at Storage Bin
Discharge ............ 39
9 Bulk Density, and Proximate and Ultimate Analysis of RDF Dis-
charged from the Storage Bin. ................ 40
10 Size Distribution of RDF Discharged from the Storage Bin. ... 41
11 Laboratory Analysis of RDF Ash 42
12 Fusion Temperature of RDF Ash 43
13 Variability of Daily Values of Characteristics of RDF Dis-
charged from Storage Bin ........... 45
14 Test of Significant Difference in Variability Between Daily
Samples of RDF Produced at Ames and St. Louis ........ 47
ix
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TABLES (continued)
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Comparison of Ames and St. Louis Mean Values of Daily Samples
Moisture Free and Ash Free Values of Daily Samples of RDF
Processing Plant Daily Operating Hours, June - December 1976. .
Plant Operating Hr Downtime and Refuse Processed/Operating Hr .
Weekly Electric Power Consumption for Refuse Processing Plant
Electric Consumption Ratios (June 1 through December 31, 1976).
RDF Conveying System-Operating Hr and Combustion Rate
Summary of Downtime for Pneumating Conveying Lines and
Summary of Capital Investment for the Ames Solid Waste
Monthly Operating Expenses and Cost Per Mg of Refuse Received
~ • "- -
49
51
56
73
76
77
82
84
85
87
87
88
93
94
96
98
100
103
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TABLES (continued)
Number Page
33 Analysis of Salaries and Wage Expense. .».. 104
34 Allocation of Salary and Wage Expense by Plant Operation . . • 105
35 Summary of Financial Operating Results 106
36 Net Cost Per Kilowatt-Hour of Net Electric Power Generated . . 108
A-l Monthly Production - Ames, Iowa, Refuse Processing Plant . . . 109
A-2 Monthly Production - Ames, Iowa, Refuse Processing Plant ... 110
B Moisture and Heating Value of Daily Samples of RDF Discharge
from Storage Bin * Ill
C-la Daily Record of Refuse Processing Plant Activity for the Month
of June 1976 117
C-lb Daily Record of Refuse Processing Plant Activity for the Month
of July 1976 121
C-lc Daily Record of Refuse Processing Plant Activity for the Month
of August 1976 126
G-ld Daily Record of Refuse Processing Plant Activity for the Month
of September 1976 131
C-le Daily Record of Refuse Processing Plant Activity for the Month
of October 1976 136
C-lf Daily Record of Refuse Processing Plant Activity for the Month
of November 1976 142
G-lg Daily Record of Refuse Processing Plant Activity for the Month
of December 1976 «• . . 146
C-2 Raw Refuse Delivered by Private Individuals 154
C-3 Processing Plant Work Station Job Description. 156
XI
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TABLES (continued)
Number Page
C-4a Daily Processing Hours—Refuse Processing Plant for the
Month of June 1976 158
C-4b Daily Processing Hours—Refuse Processing Plant for the
Month of July 1976 159
C-4c Daily Processing Hours—Refuse Processing Plant for the
Month of August 1976 160
G-4d Daily Processing Hours—Refuse Processing Plant for the
Month of September 1976 161
C-4e Daily Processing Hours—Refuse Processing Plant for the
Month of October 1976 162
C-4f Daily Processing Hours—Refuse Processing Plant for the
Month of November 1976. ••••• ......... 163
C-4g Daily Processing Hours—Refuse Processing Plant for the
Month of December 1976. ...... ...... 164
G-5 Weekly Electric Power Consumption for Refuse Processing Plant
and Storage Bin ........................ 165
C-6 Major Electric Motors—Refuse Processing Plant and Storage
Bin 167
C-7a Pneumatic Conveying from Storage Bin to Boilers Operating Hours
and Amount of RDF Burned - June 1976. 169
C-7b Pneumatic Conveying from Storage Bin to Boilers Operating Hours
and Amount of RDF Burned - July 1976. 170
C-7c Pneumatic Conveying from Storage Bin to Boilers Operating Hours
and Amount of RDF Burned - August 1976. 171
C-7d Pneumatic Conveying from Storage Bin to Boilers Operating Hours
and Amount of RDF Burned - September 1976 . 172
C-7e Pneumatic Conveying from Storage Bin to Boilers Operating Hours
and Amount of RDF Burned - October 1976 .* 173
C-7f Pneumatic Conveying from Storage Bin to Boilers Operating Hours
and Amount of RDF Burned - November 1976. ........... 174
xii
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TABLES (continued)
Number
C-7g Pneumatic Conveying from Storage Bin to Boilers Operating
Hours and Amount of RDF Burned - December 1976 175
C-8a Daily Record of Pneumatic Conveying Downtime and Maintenance -
June 1976 176
C-8b Daily Record of Pneumatic Conveying Downtime and Maintenance -
July 1976 180
C-8c Daily Record of Pneumatic Conveying Downtime and Maintenance -
August 1976 182
C-8d Daily Record of Pneumatic Conveying Downtime and Maintenance -
September 1976 184
C-8e Daily Record of Pneumatic Conveying Downtime and Maintenance -
October 1976 187
C-8f Daily Record of Pneumatic Conveying Downtime and Maintenance -
November 1976 190
C-8g Daily Record of Pneumatic Conveying Downtime and Maintenance -
December 1976 ..... 191
C-9 Daily Record of Storage Bin Downtime and Maintenance. ..... 193
D Capital Expenditures - Ames, Iowa, Solid Waste Recovery System. 196
xiii
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ACKNOWLEDGMENTS
This report was prepared for the Environmental Protection Agency under
Grant No. R803903010. It describes the work carried out by the Engineering
Research Institute of Iowa State University and Midwest Research Institute
concerning characterization of refuse derived fuel and performance and eco-
nomic evaluations of the Ames, Iowa refuse processing plant.
This EPA sponsored program was directed by Mr. Carlton G» Wiles of the
Municipal Environmental Research Laboratory} Solid and Hazardous Waste Re-
search Division, Office of Research and Development and Mr. Robert Olexsey,
Industrial Environmental Research Laboratory, Office of Energy, Minerals and
Industry.
Dr. John C. Even, Dr. S. Keith Adams, and Mr. Petros Gheresus of the In-
dustrial Engineering Department, Iowa State University, Professor Alfred W*
Joensen and Dr. Jerry L. Hall of the Mechanical Engineering Department, Iowa
State University, Mr. Charles A. Romine and Mr. Douglas E. Fiscus of Midwest
Research Institute were the principal authors of this report. Many other
Iowa State University personnel, Mr. Terry McKeighan, Mr. Kharoen Kosolcharoen,
and Ms. Lari Larson of the Industrial Engineering Department, Iowa State Uni-
versity assisted in compilation and analysis of the data.
Much of the laboratory analysis of the refuse samples and environmental
emission samples was conducted by the ERDA - Ames Laboratory under the super-
vision of Dr. Velmer A. Fassel and Mr. Howard Shanks. Also, the conduct of
these tests would not have been possible without the excellent cooperation and
assistance provided by the City of Ames personnel; Mr. Arnold 0. Chantland
(Director of Public Works), Mr. J. Keith Sedore (Director, Electric Utility),
Mr. Jerry Temple, Mr. Merlin Hove, Mr. Paul Hinderaker, Mr. Donald Riggs,
Mr. Carl Baker, and Mr. Kenneth Moravetz.
xiv
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SECTION 1
SUMMARY
The major observations regarding refuse derived fuel (RDF) characteriza-
tion and economic evaluations made during the first year of the Ames study are
highlighted in the following paragraphs.
In 1976 the refuse processing plant received 37,136 Mg of raw refuse. Of
this amount, 7% was recovered Fe-metal scrap and 84% was RDF plus plant mate-
rial loss. There appears to be no seasonal volume trend on a monthly basis
with the possible exception of April having higher volume. The heating value
of the RDF averaged 13,050 kj/kg (as received heating value). In general, the
Ames RDF is of a higher heating value than the RDF produced at St. Louis. A
statistical analysis showed that although mean values were different, there
was no difference in daily variability between Ames and St. Louis RDF. Some
seasonal trends were observed. At Ames, the RDF moisture free heating value
is lowest during the spring and summer months, and moisture content of RDF is
highest during the spring months.
There is considerable variability in the bulk density, proximate and ulti-
mate analysis and screen size of the Ames RDF. While the mean values of these
constituents were different between RDF produced at Ames and that produced at
St. Louis, there was no statistically significant difference in variability
about the mean. The composition of RDF is just as variable from day to day, at
least for the above named constituents, at Ames as it was at St. Louis. This
result is a very important conclusion which could affect future material sam-
pling programs at refuse processing plants.
The work force went through a "learning curve" in operating the refuse
processing plant, storage bin and firing facility. However, except for a
shredder bearing failure and two fires at the processing plant, the plant
operated regularly and RDF was burned almost daily. The air classifier was
a major maintenance area. During the study of electric power consumption it
was discovered that the second stage shredder uses almost twice as much elec-
tric power as the first stage shredder. A major disappointment was the alumi-
num recovery system which produced only minor amounts of marketable aluminum
scrap during 1976.
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The net cost of operating the refuse processing plant (net cost of refuse
disposal) for the total year 1976 was $18.90/Mg of raw refuse received. This
net cost is the cost after credits are given for the RDF, dump fees and recov-
ered metals. Improvtnents in net cost can be achieved by reducing operating
expenses and increasing the volume of raw refuse received. The economic model
of the plant shows that volume increase is the most attractive method of re-
ducing net cost. Improvements in the revenue received for recovered materials
will occur in future years primarily due to a projected annual 10% to 1570 in-
crease in coal costs at Ames. This increase in fuel cost at the Ames Municipal
Electric Utility will increase the credit given to RDF produced at the refuse
processing plant. In future years there will undoubtedly be increases in such
items as the cost of maintenance parts due to inflation and higher wage rates.
However, the refuse processing plant has the capacity to process more than twice
as much refuse as was processed during 1976. If additional large amounts of
refuse can be obtained from nearby communities it is predicted that a dramatic
reduction in the net cost of operating the refuse processing plant will result.
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SECTION 2
INTRODUCTION
The grant for the first year of research was awarded February 5, 1976.
The work plan was submitted in March 1976• Characterization of RDF was con-
ducted March 17 through June 14, 1976. Boiler environmental emission sam-
pling, boiler performance and boiler tube corrosion studies and economic eval-
uation of the refuse processing plant and the RDF firing facility commenced
in June 1976. In addition, the City of Ames made available the results of their
sampling and analysis of RDF heating value and moisture for the full year 1976.
Results and conclusions from the boiler environmental emission studies and
the boiler performance and corrosion studies conducted on the two stoker boilers
are being prepared in separate reports suitable for publication and will be
available at a later date.
This final report of the first year's activities presents a summary of the
environmental results and the results and conclusions from the economic eval-
uation of the resource recovery facility and the characterization of RDF pro-
duced.
Objectives of the portion of the research work reported in this report
were as follows:
• Evaluate the stoker boilers for the effect on environmental emissions
and boiler performance of burning coal plus RDF versus coal only.
• Evaluate the refuse processing plant monthly production records for
possible trends and report the amount of refuse processed and the
amount of recovered material.
• Characterize the RDF produced for bulk density, proximate and ulti-
mate analysis, screen size, ash chemical composition, and ash fusion
temperatures.
. Evaluate the operation of the resource recovery facility in terms of
start-up experience, labor and maintenance required, power consumption,
plant downtime and malfunction of equipment.
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• Evaluate the capital investment required to build the resource re-
covery facility and evaluate the operating expense and revenues re-
ceived from recovered materials.
The findings from the first year's evaluations and a discussion of the
results and conclusions are presented in the following sections.
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SECTION 3
SUMMARY OF ENVIRONMENTAL EMISSIONS AND PERFORMANCE OF
THE STOKER-FIRED BOILERS
This section provides a synopsis of the major results and conclusions to
date of the environmental emissions and boiler performance investigations on
the stoker-fired steam generator units Nos. 5 and 6, at the City of Ames, Iowa.
Complete reportsil^/ of the environmental investigations, including anal-
yses of the boiler bottom-ash, fuel inputs, and all of the test data are cur-
rently in the process of being prepared for publication. The analysis and
interpretation of results, including statistical analysis is not yet complete,
so the following excerpts must be considered preliminary.
POWER PLANT DESCRIPTION
Three boiler units, 5, 6, and 7, at the Ames Municipal Power Plant have
been modified to burn solid waste as a supplemental fuel with coal. Boilers
5 and 6 are stoker-fired boilers and boiler 7 is a pulverized coal suspension-
fired boiler. Because of boiler unit availability at the power plant, major
research emphasis was on the environmental evaluation and boiler performance
of the stoker-fired units Nos. 5 and 6 while firing coal and coal plus RDF.
The characteristics of the two stoker-boiler units are summarized in Table 1.
EXPERIMENTAL DESIGN, SAMPLING LOCATIONS, AND ANALYTICAL METHODOLOGY
A block diagram showing the sample locations is included in Figure !•
All of the sampling was conducted on a regular basis according to the test sum-
mary of environmental sampling shown in Tables 2 and 3, except heavy organic
species which were sampled on intermittent days as manpower, instrumentation,
and equipment would allow.
Table 4 summarizes the sampling and analytical procedures used.
I/ Special Report - Part II, "Evaluation of the Stoker-Fired Steam Generators
at the City of Ames, Iowa," (draft). EPA No. R803903-014.
2/ Special Report - Part III (with appendices), "Environmental Evaluation of
the Stoker-Fired Steam Generators at the City of Ames, Iowa," (draft).
EPA No. R803903-014, ERDA No. W-7405 ENG - 82.
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TABLE 1. CHARACTERISTICS OF AMES MUNICIPAL POWER PLANT STOKER-FIRED
STEAM GENERATORS
Manufacturer
Electrical output - MW
Installation date
Pressure/ temperature
pKa/°C
(psi/°F)
Nominal steam output capacity
kg/hr
(Ib/hr)
Coal firing equipment
Furnace pressure
Dust collection equipment
Stack height
meters
(feet)
Heat input at nominal capacity
MJ/hr
(Btu x 106/hr)
5
Riley
7.5
1951
4895/441
(710/825)
43,100
(95,000)
Spreader
Stoker
Traveling
Grate
Balanced
Draft
Western
Multiple
Cyclone
61
(200)
154
(146)
Unit
6
Union Iron Works
12
1958
4999/441
(725/825)
56,700
(125,000)
Spreader
Stoker
Traveling
Grate
Balanced
Draft
American Blower
Multiple
Cyclone
61
(200)
202
(191)
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Flow Rate
Ultimate Analysis
Heating Value
Chemical Analysis & Trace Elements
Ash Softening Temperature
Emission Rates of Particulate
Filter Particulate Trace Elements
Impinger Water Trace Elements
Emissions to Atmosphere
Humidity
Barometer
Intake
Temperature
Coal
Air
Volume Flow
Density
Ultimate Analysis
Heating Value
Chemical Analysis &
Trace Elements
Ash Softening
Temperature
RDF
Feedwater
Boiler Unit
Temperature
Flow Rate
Emission Rates of Particulate
and Gaseous Species
Particulate Trace Elements
Impinger Water Trace Elements
Particulate Sizing
Grate Ash
(Bottom
Ash)
Hopper Ash
(Collected
Fly Ash)
Flow Rate
Chemical Analysis &
Trace Elements
Ash Softening Temperature
Steam
Flow Rate
Chemical Analysis &
Trace Elements
Softening Temperature
•Denotes Sampling Location
Figure 1. Boiler units nos. 5 and 6 sampling locations.
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TABLE 2. SUMMARY OF EXPERIMENTAL DESIGN
(Numbers shown are test numbers referenced in the following Table 3.)
Stoker boiler No. 6
Stoker boiler No. 5 coal used: mixture of
coal used: Iowa 50% Iowa, 50% Wyoming
Xs^^ % Load
% RDpX. 60
4A, 4B
20
0 36i'
8
20 9A, 9B
33
1
50 34
35
80
5
16
17
6
12
13
2
10
15
100
11
31^'
32b/
7
14
19
3
18
c/
X. % Load
% RD>\^ 80^
24
0 29
30
25
20 26
27
22
50 23
28
a/ Test 21 conducted while pulling ash from boiler to determine any change in
performance and/or emissions due to ash removal.
b_/ Bottom ash not weighed because of ash removal difficulties (slagging in
boiler and clinkering of ash).
£/ Boiler No. 5 cannot operate at 100% steam load and 5070 RDF without severe
ash problems due to lack of excess air. Therefore, the third test in series
was not conducted.
d/ Load was changed from the originally planned 100% to 80% steam load to be
more typical of capability of boiler and air supply for refuse burning.
This change was essential from experience gained during testing of Boiler
No. 5.
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TABLE 3. TEST SUMMARY OF ENVIRONMENTAL SAMPLING
Date
6- 8-76
6-10-76
6-15-76
6-17-76
6-21-76
6-23-76
6-25-76
6-28-76
6-30-76
7- 2-76
7- 6-76
7- 8-76
7- 8-76
7-16-76
7-17- 7u
7-19-76
7-19-76
7-23-76
7-24-76
8- 2-76
8- 2-76
7-26-76
Unit
15
15
IS
j5B-Bd/
15
15
15
15
#5B-Bd/
15
t5
#5»-Bd/
#5B-U<1/
15
15
#5B-fld/
#5B-B<1/
05
t5
ff^-aai
#5B-Bd/
15
ZLoad
60%
80%
100%
60%
80%
80%
100%
60%
60%
80%
10QZ
80%
SOX
100%
80%
80%
80%
100%
100%
60%
60%
60%
Fuel I/
C+RDF
C+RDF
C+RDF
C
C
C+RDF
C+RDF
C+RDF
C+RDF
C+RDF
C
C+RDF
C+RDF
C+RDF
C+RDF
C
C
C+RDF
C+RDF
C
C
C+RDF
ZRefuse
50%
50%
50%
0%
0%
20%
20%
20%
20%
50%
0%
20%
20%
20%
50%
0%
0%
50%
20%
0%
0%
50%
Teat
Designation
EPA 1
EPA 2
EPA 3
EPA 4i/,A & I
EPA 5
EPA 6
EPA 7
EPA 8
EPA 9l/A 8. U
EPA 10
EPA 11
EPA 12^'
EPA 13-^
EPA 14
EPA 15
EPA 16Jl/
EPA 17-'
EPA 18
EPA 19£/
EPA 20^
EPA 2l4il/
EPA 1-Supp.
Bui torn
/
/
/
//
/
/
/
/
//
/
/
/
/
/
/
/
/
J
J
/
/
—
Collector
Ash
/
/
/
//
/
/
/
/
//
J
J wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
—
Pan leu 1 ai i£/
BPC
/
,/
/
//
/
/
/
/
//
/
/
/
/
/
/
/
/
/
J
/
/
—
S
/
/
/
/,
/
/
/
/
/.
J
J
-------
TABLE 3. (continued)
Date
'•B~ 5-76
8- 6-76
8- 9-76
8-10-76
8-11-76
8-12-76
8-13-76
8-16-76
8-18-76
8-24-76
8-24-76
8-25-76
8-26-76
'8-26-76
8-27-76
Unit
16
06
*6
•16
16
16
»6
06
(6
#5B-Bd/
#5B-Bd/
*5
#5B-Bd/
#5B-Bd/
J5
ZLoad
BOX
802
80?
80Z
80Z
80Z
80Z
80Z
80Z
100Z
100Z
60Z
60Z
602
60Z
Fuels'
C+RDFi
C+RDF
C
C+RDF
C+RDF
C+RDF
C+RDF
C
C
C
2
C+RDF
C+RDF
C+RDF
C
ZRefuse
50Z
50Z
OZ
20Z
20Z
20Z
50Z
OZ
OZ
OZ
OZ
20Z
50Z
50Z
OZ
Test
Designation
EPA 22
EPA 23
EPA 24
EPA 25
EPA 26
EPA 27
EPA 28
EPA 29
EPA 30
EPA 31
EPA 32
EPA 33
EPA 34
EPA 35*
EPA 36
Bottom
Ashfe/
/
/
/
^
/
/
/
/
/
,/£/
/*'
J
/
/
/
Collector
Ash
/ wt
/ wt
/ wt
J wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
/ wt
Particulatecy
BPC
/
/
/
/
/
J
J
/
/
/
/
^
/
/
/
S
/
/
/
/
J
/
/
/
J
J
/
/
/
/
/
Sizing
/
/
/
/
/
y
/
/
/
,/
/
/
/
/
/
Orsat
BPC
/
/
J
/
J
/
/
/
/
/
/
/
/
/
/
S
/
/
/
/
/
/
J
/
/
/
/
/
/
/
/
!!i
ore
s
^
/
/
/
/
/
/
/
/
/
/
/
/
/
/
so
X
BPC
S
/
/
/
/
/
/
/
^
/
/
/
/
/
/
J
Aldehydes
Ketones
BPC
S
/
/
/
/
J
/
/
/
/
/
/
/
/
/
/
Chlorides
Org. Acids
BPC
S
/
/
J
/
/
/
/
/
/
J
/
/
/
/
/
llg.Be.Se
BPC
S
/
/
/
/
/
/
/
/
/
J
/
y'
/
/
J
Heavy
Organ t_M
BPC
S
HC & N,0
BPC
S
/
/
/
/
/
/
/
J
/
a/ Coal for tests on Boiler No. 5 is Iowa coal; on No. 6, 507. Wyoming and 50% Iowa coal.
b/ Bottom Ash and Collector Ash weighed together after completion of test and removal of ash to ash silo except where special weights are noted.
c/ BPC - Before Particulate Collector; S = Stack; Sizing = Sizing on stack.
$/ B-B indicates back-to-back testing.
e/ Boiler load dropped and test terminated early*
fj Test conducted while pulling ash to determine if boiler performance and emissions change when ash is pulled.
gj Bottom ash not weighed due to ash removal difficulties.
-------
TABLE 4. SUMMARY OF SAMPLING AND ANALYTICAL PROCEDURES
FOR BOILER ENVIRONMENTAL EMISSIONS
Sampling technique
Analytical procedure
Fuel into boiler
. Coal
. RDF
Combustion
. Air
Ash
Grate (bottom
ash)
Collected fly
ash (hopper
ash)
Hourly samples combined
to form single composite
sample
Thermometry
Grab samples combined
to form single com-
posite sample
Steam
Fly ash
Before par-
ticulate
collector
Stack
Andersen im-
pactor
EPA Method 5
Trace elements via x-ray
fluorescence (XRF)
Ash via ASTM method
Moisture via ASTM method
HHV via ASTM method
Wet bulb and dry bulb tem-
perature
Trace elements via x-ray
fluorescence (XRF) or ap-
propriate ASTM method
Ash via ASTM method
Moisture via ASTM method
HHV via ASTM method
Trace elements in grab sam-
ple composite taken from
particulate collector hop-
per ash)
Flow rate
Temperature
Pressure
Size distribution via im-
pactor (stack only)
Trace elements in material o
on filter via XRF
Trace elements in impinger
solutions via an Inductively
Coupled Plasma Analytical
System (ICP)
(continued)
11
-------
TABLE 4. (continued)
Sampling technique
Analytical procedure
Flue gas
. Stack
Orsat
EPA Method 7
EPA Method 6
Modified EPA Method 5
Modified EPA Method 5
Modified EPA Methods
5 and 6
Modified EPA Method 5
Grab sample
Aspiration across col-
umn of macro-reticular
resin
C02, CO, 02, N2
NOX
so2
Aldehydes and ketones via
method of Carotti and
Kaiser
Organic acid via ion chro-
matograph
Cyanide via ion selective
electrode
Phosphorus via spectro-
photometer
Chlorides via colorimetric
and spectrophotometric
analysis of part of im-
pinger solutions from SOX
and cyanide train
Mercury, arsenic, antimony
and beryllium via ICP
Ci and Cg hydrocarbons via
gas chroraatography
Organics (PCB, POM, etc.)
via gas chromatograph-mass
spectrograph (intermittent
days)
12
-------
BOILER PERFORMANCE
RDF in combination with coal was successfully fired in the stoker boilers
with some difficulty but with no major problems. A high refuse fuel utiliza-
tion rate was encountered. There was no significant direct effect of burning
RDF on the measured boiler thermal efficiency. There was no significant dif-
ference in the percent of the heat input leaving as combustibles in the ash,
the average being approximately 57o for both coal and RDF. However, based on
the current method of RDF injection, high excess air flow rates were encoun-
tered which resulted in an indirect effect on boiler thermal efficiency. The
RDF pneumatic feeders and the additional over fire air increased the secondary
air (excess air).supplied. The increase in excess air required to burn RDF
reduced the boiler thermal efficiency. There was general consensus among the
boiler operators that more combustion air through the grate is necessary when
firing RDF to prevent slagging and to maintain a proper fire bed.
Ultimate fouling of the superheater section of boiler No. 5 was experi-
enced. Calculation of the fuel fouling index correlates with this behavior.
The most significant influence is the higher sodium content of RDF which has
a detrimental effect on the fouling index. Soot blowers will be installed to
reduce this fouling behavior. In addition, an alternate method of RDF injec-
tion might reduce this effect.
At most boiler loads, bottom ash tended to increase somewhat and fly ash
tended to decrease with increasing percent RDF.
Ash fusion temperatures of RDF are typically 60 to 100°C lower than for
coal. However, no specific correlation of boiler performance to ash fusion
temperatures has been determined.
ENVIRONMENTAL EMISSIONS
In coal plus RDF firing applications, there are a variety of air pollu-
tion control devices that could be used, such as multiple cyclones, scrubbers
and electrostatic precipitators* Therefore, the change in uncontrolled emis-
sions due to burning RDF is of great interest to the designer of future refuse
burning installations. The following discussion presents a summary of the un-
controlled emissions due to burning coal only and to burning coal plus RDF.
Excess air before the particulate collector (BPC) particulate, stack par-
ticulate, particulate collector efficiency, stack particle size distribution,
NOX, SOX, chloride, formaldehyde, cyanide and phosphate emission rates, all
as functions of RDF input, are given in Figures 2 through 11, respectively.
13
-------
1601-
140
120
100
80
8
u
X
UJ
60
40
20
Boiler 5
-A - A-
Boiler 6
60% Steam Load
80% Steam Load
100% Steam Load
—• •-- 80% Steam Load
I
I
I
20 40
RDF Heat Input -%
Figure 2. Percent excess air as a function of RDF heat input.
60
14
-------
5.or
4.0
Q.
c
o
V
o 3.0
&
o
6
I
4)
O
| 2.0
o
L.
o
1.0
Uncontrolled
Emissions Before
the Parti cu late
Collector
Boiler 6
60% Steam Load
80% Steam Load
100% Steam Load
80% Steam Load
Stack Emissions After the
Particulate Collector
I
I
20 40
RDF Heat Input - %
60
Figure 3. Particulate emissions as a function of RDF heat input.
15
-------
100 r-
90
I
0s 80
c
V
« T; i
.2 E
O Uul
1°-= 70
:E o
3 U
2 «
O
S 60
a.
50
Collector Efficiency
Ames Power Plant
Boilers 5 and 6
Boiler 5
-• ••
-• B
-A A
Boiler 6
60% Steam Load
80% Steam Load
100% Steam Load
—• •— 80% Steam Load
20 40
RDF Heat Input - %
60
Figure 4. Particulate collector efficiency as a function of
RDF heat input.
16
-------
in
e
o
i
o
10
O
10
9
8
7
6
5
4
to
V
~o 2
£
1.0
i
i
i
Boiler 5
Avererage of All
Steam Loads
0% RDF
20% RDF
50% RDF
10 20 30 40 50 60 70 80
Cumulative Pet. Less Than D
-------
Boiler 5
O O-
D a-
A A-
Boiler 6
60% Steam Load
80% Steam Load
100% Steam Load
— B B— 80% Steam Load
I
20 40
RDF Hear Input - %
Figure 6» NOX stack emissions as a function of RDF heat input.
60
18
-------
3.0
60% Steam Load
80% Steam Load
100% Steam Load
Boiler 6
a.
o
0)
X
.9-
"o
O)
o
6
V>
VI
• ^
E
3
co
2.0
— B g— 80% Steam Load
I
I
0
20 40
RDF Heat Input -%
60
Figure 7. Sulfur stack emissions as a function of RDF heat input,
19
-------
Boiler 5
—8 o— 60% Steam Load
— H a— 80% Steam Load
—A A— 100% Steam Load
Boiler 6
—Q a— 3Qo/0 steam Load
I
20 40
RDF Heat Input, %
Figure 8. Chloride stack emissions as a function of RDF heat input.
60
20
-------
3
0_
O
I
O)
8
v>
O
LU
0)
0)
\
E 4
0
Boiler 5
® ©— 60% Steam Load
B B— 80% Steam Load
± ^— 100% Steam Load
Boiler 6
B Q— 80% Steam Load
\
0
20 40
RDF Heat Input -%
60
Figure 9. Formaldehyde stack emissions as a function of RDF heat input
21
-------
0.4
D
QL
c
D
X
-5 0.3
o_
"o
O)
E
D
0>
0.2
c
o
0.1
-------
Boiler 5
60% Steam Load
80% Steam Load
100% Steam Load
20 40
RDF Heat Input, %
Figure 11. Phosphate stack emissions as a function of RDF heat input.
23
-------
In addition, organic compounds in stack emissions and trace elements in BPC
particulate (fly ash) are given in Tables 5 and 6, respectively.
TABLE 5. ORGANIC COMPOUNDS IN STACK EMISSIONS
Compound
Stack gases
(ug/1,000 m3)
Particulates
(ng/g)
Naphthalene
Acenaphthalene
Fluorene
Anthracene
Fluoranthene
Pyrene
Benzof luorenes (1,2 and 2,3)
1,2-Benzanthracene
a- and e-Benzyprenes and perylene
20-Methylcholanthrene
Dibenzanthracenes (1,2-3,4 and A,H)
Dibenzanthracene (2,3-6,7)
Coronene and 3,4-9,10 dibenzopyrene
Aliphatic hydrocarbons
BDL3./
BDL
36.5
BDL
119
36.5
54.7
BDL
72.9
BDL
BDL
BDL
BDL
31,700
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
0.42
BDL
BDL
BDL
BDL
340
Detection limits
35 ug/1,000 m3
0.35 ng/g
a/ BDL - Below detection limit.
24
-------
TABLE 6. CALCULATED!!/ TRACE ELEMENTS IN UNCONTROLLED PARTICULATES
Concentration (mg/MJ) for boiler No. 5 and 1007, load
Element
Aluminum
Potassium
Calcium
Titanium
Vanadium
Chromium
Iron
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Rubidium
Strontium
Lead
Al
K
Ca
Ti
V
Cr
Fe
Ni
Cu
Zn
Ga
Ge
As
Se
Rb
Sr
Pb
0% RDF
306
50.4
374
15.7
2.65
0.822
398
0.368
0.375
13.8
0.55
1.5
0.57
0.056
0.406
1.36
8.71
20% RDF
104
32.2
176
8.74
1.21
0.375
150
0.121
0.376
13.3
0.49
0.39
-
0.037
0.0724
0.362
13.6
50% RDF
106
24.6
216
10.79
1.31
0.553
181
0.099
0.598
11.2
0.34
0.20
-
0.039
0.1012
0.451
9.61
a/ Calculated from sum of stack emission particulates and collected fly ash.
All values reported in Tables 5 and 6 and Figures 2 through 11 are aver-
ages of results from the test replications of each boiler load and percent
RDF. The number of replications for each test condition is shown in Table 2.
Table 6, trace element analysis of the uncontrolled particulate emissions,
was devised by combining the analysis of the stack emission particulates and
the analysis of the fly ash samples from mechanical particulate collector ash
hoppers.
The results show trends based on calculated averages. The decision as to
whether or not these trends are statistically significant must wait until the
ongoing statistical analysis of the results is complete. Also, at 100% steam
load and 50% RDF, boiler No. 5 experienced a lack of combustion air due to in-
sufficient induced draft fan capacity with resulting boiler operational prob-
lems. Therefore, this test condition may not be typical of normal boiler
operation.
25
-------
No significant hydrocarbon emissions in the C^ to 65 range have been found
to date. Results from the organic acids analysis and the mercury train are not
yet available.
Both uncontrolled particulate emissions before the particulate collector
and stack particulate emissions to the atmosphere did not have clear overall
trends as a function of RDF heat input. Particulate emissions either in-
creased with percent RDF depending on boiler unit and boiler load. Particulate
collector efficiency initially increased with increasing percent RDF then de-
creased with additional RDF input. While no particulate sizing was done be-
fore the particulate collector, it is believed that the particles in the flue
gas are larger when burning RDF. Therefore, the multiple cyclone particulate
collector efficiency increases with increased RDF. However, the increased air
flows with RDF help carry more particulate through the collector, thus de-
creasing its efficiency after optimum flow rate is reached.
NOX and sulfur emissions both have trends of decreasing emissions with
increased percent RDF. The major exception is sulfur emissions for boiler
No. 5 at 60% steam load and 20% RDF. This condition had sulfur emissions com-
parable to coal only at higher boiler steam loads. The reason for this high
sulfur emission at this test condition is believed to be due to an unusually
high amount of sulfur in the coal for this particular test.
During these tests, boiler No. 5 used Iowa coal only. Boiler No. 6 used
a mixture of one-half Iowa and one-half Wyoming coal. Wyoming coal is lower
in sulfur content than Iowa coal and thus sulfur emissions for boiler No. 6
are lower, and the effect of RDF is not as pronounced.
Chloride emissions increased with increasing percent RDF for all boiler
loads. Chloride emissions were substantially lower for coal only than for
coal plus RDF, being approximately 0.02 g/megajoules or less. The coal plus
RDF emissions therefore appear to be a function of the chlorine in the RDF.
Formaldehyde, cyanide, and phosphate emissions were quite variable, with
no clear trends of emissions as a function of percent RDF. Emissions at 20%
RDF were either lower, or only slightly higher than the coal only emissions,
the major exception being cyanide emissions from boiler No. 6 which showed
a relatively sharper increase in emissions at 20% RDF than for the other test
conditions. However, at 50% RDF, the increases and decreases from the 20%
RDF test condition were variable enough to make it difficult to establish a
trend based on percent RDF.
The heavy organic compounds in the stack emissions are shown in Table 5.
Many of the heavy organic compounds analyzed were below the laboratory detec-
tion level and the majority of the organics found were in the stack gases and
26
-------
not In particulate form. These data are the results of only two stack samples
performed to assess the potential presence of such compounds. Therefore, no
comparisons of emissions as a function of percent RDF can be made at this time.
Table 6 presents the trace element analysis for the uncontrolled particu-
lates (BPC fly ash) as a function of percent RDF. There were increases due to
burning RDF in only two of the 19 elements analyzed. Only copper and lead showed
increases.
27
-------
SECTION 4
REFUSE PROCESSING PLANT MONTHLY PRODUCTION
The amount of refuse processed during the year 1976 and the amount of RDF
and recovered materials derived from this raw refuse are summarized below:
Raw refuse processed 37,136.53 100.0
RDF (by difference)^/ 31,261.08 84.18
Fe-metal 2,594.69 6.99
Non Fe-metal 4.67 0.01
Wood chips 295.69 0.79
Glass and grit 217.30 0.59
Rejects to landfill 2,763.10 7.44
a/ Raw refuse less Fe-metal, non-Fe-metal, wood chips,
glass and grit, and rejects to landfill. Includes
any plant material loss.
Appendix Tables A-l and A-2 contain the monthly production records in terms of
actual weight and the conversion to percentages.
Figure 12 is a graphical presentation of the monthly amount of raw refuse
received. The month of November is low because of 10 days of lost production
due to a fire at the processing plant. There is little variation from month
to month in the amount of raw refuse received except that April is higher than
any of the other months. Whether or not this is a seasonal trend due to spring
cleaning, etc., will be verified by comparison to monthly volume in future
years.
The two major volumes of products produced by the refuse processing plant
were RDF and ferrous metal scrap. Figure 13 shows the amount of RDF and ferrous
metal as a percent of the raw refuse received. There is little variation in
the monthly percentages. The plant is operating consistently in terms of the
amount of these two major products produced.
28
-------
4000
NJ
VO
3000
2000
1000
Plant not in Operation
for 10 Days Due to Fire
I
M
M
J A
Month, 1976
O N
D
Figure 12. Monthly amount of raw refuse received.
-------
ioo r
90
80
0)
u
p
&
I
70
20
RDF by Difference
(Incoming Raw Refuse Less
Recovered By-Products
and Rejects)
Recovered Ferrous Metal By-Product
10
0
M
M J J A
Month, 1976
O
N
j
D
Figure 13. RDF and Fe-metal as percent of raw refuse.
30
-------
SECTION 5
CHARACTERIZATION OF RDF
RDF was characterized by two separate methods. The first method included
daily samples of RDF taken by the City of Ames on 286 different days through-
out the year 1976, and analyzed for moisture and heating value. The second
method included 14 days of samples analyzed for bulk density, screen size,
proximate and ultimate analysis, ash chemical analysis and ash fusion tempera-
ture. Results from these samples show the range of RDF moisture and heating
value over the whole year along with a very detailed analysis of RDF for a
few days during the year.
MOISTURE AND HEATING VALUE OF DAILY SAMPLES OF RDF TAKEN BY THE CITY OF
AMES DURING THE YEAR 1976
Daily values of moisture and heating value of RDF for 286 days from
January 2 through December 31, 1976, are contained in Appendix Table B-l.
These samples were taken by the City of Ames to determine heating value of
RDF so that proper credit could be given the refuse processing plant for the
fuel it produces. The City of Ames has made this information available to
show the daily variability of RDF.
Sampling Procedure
Daily samples were taken from the discharge of the storage bin as RDF
was being fed to the boilers. The storage bin bottom is fitted with drag con-
veyors which discharge into a chute leading to the pneumatic conveying system
which delivers RDF to the boilers. Once per day, between 7 and 9 a.m., a
1 liter (1 qt) sample of RDF was manually taken from the top of a selected
drag conveyor using a 1 liter scoop. This 1 liter sample was placed in a
plastic bag, sealed airtight and sent to the laboratory for analysis. As
shown in Appendix Table B-l samples were taken generally every workday, with
exceptions for some weekend days, holidays, etc.
31
-------
Results
Table B-l in the Appendix shows the date the sample was taken. However,
because the samples are the discharge from the storage bin they cannot be cor-
related to any specific day of the week. The storage bin has a storage capac-
ity of 456 Mg (500 tons) of RDF. Plant production of RDF is approximately 120
Mg/day. Normal operation is for continuous burning of RDF in the boilers so
that RDF consumed during a week matches the RDF produced for the week. How-
ever, for any particular day the RDF being discharged from the storage bin
could be RDF produced that day or a previous day, or a mixture of RDF from
two or more days of plant production.
Appendix Table B-l shows the normal daily variation in RDF moisture and
heating value. Figure 14 is a graphical presentation of daily moisture and
heating value over the total 1 year period. Moisture free heating value is
plotted versus days because as received heating value is obviously affected
by moisture content. An analysis of Figure 14 reveals that daily values of
moisture and heating value vary considerably and this variability appears to
be random. A statistical test of correlation between moisture and day of the
year, and heating value and day of the year was conducted. The results of
this indicate no significant statistical correlation between daily values and
day of the year.
However, when the monthly average values are compared, there are some
seasonal trends present. Statistical analysis of variance tests revealed
significant differences between some of the monthly average values. Figure
15 presents the monthly mean values. During 1976, moisture free heating value
was lower in the spring and summer months. November had the highest mean
value. However, the November data include only 13 days of samples because
of plant unavailability due to a fire.
Variation of RDF moisture content by month is not as pronounced as is the
heating value variability. Moisture content was highest during the spring
months which is what would be expected due to spring yard cleanup, etc. How-
ever, all the reasons for seasonal trends, if present, are not known from the
study thus far. The composition study of RDF planned to be conducted during
1977 may present information allowing a greater understanding of the reasons
for the seasonal trends.
For a 1-year period extending from September 1974 through September 1975,
the St. Louis Refuse Processing Plant was evaluated.I/ This evaluation
I/ Fiscus, D. E., P. G. Gorman, M. P. Schrag, L. J. Shannon. St. Louis Demon-
stration Final Report: Refuse Processing Plant Equipment, Facilities,
and Environmental Evaluations. Prepared for U.S. Environmental Protec-
tion Agency by Midwest Research Institute, Kansas City, Missouri, April
15, 1977.
32
-------
20
AMES, IOWA
CO
OJ
17
2
I
16
'5 15
13
3s"
30
20
u. 15
JAN
FES
MAR
APR
MAY
JUN
JUl
AUG
SEP
OCT
NOV
DEC
Figure 14. Daily values of RDF moisture and heating value.
-------
19
CO
o
^ 18
I X
0) O)
-------
included daily samples of RDF analyzed for heating value and moisture. There-
fore, a comparison can be made between the RDF produced for 1 year at St.
Louis and the RDF produced for 1 year at Ames. This comparison is shown in
Table 7. These results represent 28,053 Mg of municipal solid waste processed
at St. Louis during the 12-month period and 37,137 Mg processed during 12
months at Ames. Since daily samples of RDF discharged from the storage bin at
St. Louis were taken for only 10 days, the only year long period that can be
compared to Ames are daily values of RDF entering the storage bin at St. Louis.
A statistical analysis of the St. Louis data showed that there was no signifi-
cant difference between RDF entering or being discharged from the storage bin.
Therefore, comparison of RDF entering the storage bin at St. Louis versus RDF
leaving the storage bin at Ames is valid. Mean values were compared utilizing
the test of statistical difference between independent samples. All three
means were significantly different.
RDF BULK DENSITY, PROXIMATE AND ULTIMATE ANALYSIS, SCREEN SIZE, AND ASH
CHEMICAL ANALYSIS AND FUSION TEMPERATURE
Values of moisture and heating value of RDF for a full year on the basis
of samples taken by the City of Ames were presented in the preceding section
(4). To provide a more complete characterization of RDF, 14 daily samples of
RDF discharged from the storage bin were taken by personnel of the Iowa State
Engineering Research Institute during the period March 17 through June 14, 1977.
Samples were analyzed for bulk density, proximate and ultimate analysis and
ash analysis. Samples from nine of these 14 days were sized, using a labora-
tory sieve machine. This was done to check out the sizing procedure and
laboratory equipment.
Sampling Procedure
Figure 16 shows the procedure used for sampling and determination of
bulk density. Once per hour, the 16.8 liter sampling container is placed in
the discharge chute below the drag conveyor discharge. The container is al-
lowed to fill with RDF and then is removed from the discharge chute. The con-
tainer is leveled off and the amount of RDF in the container weighed. After
the weight is determined, a portion of this collected RDF is placed in a
separate container to form a daily composite sample. The storage bin has
four drag conveyors. If more than one conveyor is in use, the above proce-
dure is repeated for each conveyor being used.
A minimum of four samples per day were taken. The bulk density reported
each day is the total weight of RDF collected divided by the total volume
collected:
35
-------
TABLE 7. COMPARISON OF DAILY SAMPLES OF RDF TAKEN OVER 1 YEAR PERIOD, ST. LOUIS - SEPTEMBER
1974 THROUGH SEPTEMBER 1975, AMES - JANUARY THROUGH DECEMBER 1976
Heating value (kj/kg)
Moisture %
Characteristic
Mean X
Maximum value
Minimum value
Number of samples, n
Standard deviation, Sx
St. Louis
26.55
42.2.
2.3
97
7.275
Ames
22.23
36.38
4.31
286
4,864
As received
St. Louis
10,636
13,613
6,932
97
1,370.3
Ames
13,188
16,970
9,678
268
1,297.2
Moisture
St. Louis
14,494
16,816
10,503
97
1,400.5
free
Ames
16,967
20,239
13,023
268
1,141.0
-------
Handle-
Bulk Density
Sample Container
Volume =0.0167749m3
(0.5924ft3)
Inner Cone of Atlas Bin
RDF Conveyed in
Trough in Bin Floor
Bin Floor
Drag Bars
Drag Conveyor
-Discharge Chute
To Airlock Feeder
for Pneumatic
Conveying System
PROCEDURE
Sample container placed below drag conveyor discharge, container filled
and then removed from discharge chute. Container then leveled off and
weight determined.
Two or more conveyors normally used for conveying refuse. Above procedure
repeated for each conveyor in use. Bulk density reported is total weight
of RDF collected divided by total volume.
_ ,, _ . £ sample container weight
Bulk Density = — v ,., 0
(Number of samples) (0.0167749 m3)
Figure 16. Procedure for determination of bulk density.
37
-------
_ ., _, . S: sample container weight
Bulk density =
(Number of samples) (0.0167749 m3) = kg/m3
This procedure is different from that used by the City of Ames as described
previously. The primary difference is that the RDF is sampled in a free fall
condition while the City of Ames samples were taken from the top of a con-
veyor. Also, the laboratory analysis sample is the composite of a minimum of
four individual daily samples taken 1 hr apart. This procedure is unlike the
daily sampling of RDF by the City of Ames, which used only one daily sample
for analysis.
Laboratory Results
Table 8 shows the sampling schedule and the identification of each sample
number as to the date and day of the week it was taken. The data in Tables 9
through 12 use only the sample number for identification.
Table 9 presents the values of bulk density and proximate and ultimate
analysis. The screen size distribution is reported in detail in Table 10. To
make comparisons easier, the geometric mean diameter and the geometric stan-
dard deviation were calculated. This method assumes a straight line logarith-
mic distribution of particle size. The geometric mean diameter is the size at
which half the particles are larger than the mean and half are smaller. The
geometric standard deviation is the dispersion about the mean. A value close
to 1 indicates a small dispersion, while a large value indicates that par-
ticles are widely distributed over a large size range.
In early March 1976, the second stage shredder was taken out of service
due to a bearing failure and was not placed back in service until March 28,
1976. Therefore, Samples Nos. 1 and 2 are single shredded RDF. The major ef-
fect of single versus double shredding is on particle size. Therefore, the
particle size mean values were calculated only for the double shredded RDF.
Table 11 shows the chemical analysis of RDF ash and Table 12 lists the
fusion temperatures of RDF ash. The major constituent of RDF ash is silica
(SiC>2), one of the important items used in determining the slagging charac-
teristics of an ash. It is desirable to have low silica content. However,
interpretation of these ash analyses results, as well as the ash fusion tem-
peratures, can best be made after the same categories of data are available
for the specific coals used at Ames.
38
-------
TABLE 8. SAMPLING SCHEDULE RANDOM SAMPLING OF RDF AT STORAGE
BIN DISCHARGE
Sample number Day of week Date (1976)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Wednesday
Tuesday
Friday
Wednesday
Thursday
Monday
Tuesday
Thursday
Wednesday
Thursday
Tuesday
Friday
Monday
Monday
March 17a/
*^ m
March 23^'
April 2
April 7
April 15
April 19
April 27
May 6
May 12
May 20
May 25
June 4
June 7
June 14
a/ Single stage shredding due to second stage shredder out of service be-
cause of bearing failure. Second stage shredder back in service on
March 28, 1976, and Tests 3 through 14 are double shredded refuse.
39
-------
TABLE 9. BULK DENSITY, AND PROXIMATE AND ULTIMATE ANALYSIS OF RDF DISCHARGED FROM THE STORAGE BIN
(As received, all percents by weight ASTM Method D271 for all values except bulk
density)
Sample No.
(test day)
1
2
3
S 4
5
6
7
8
9
10
11
12
13
14
Bulk
density
(kg/m3)
134.7
97.0
152.2
104.4
129.5
157.0
127.8
122.5
156.0
137.6
122.4
116.1
125.5
113.8
Heating
value
(kj/kg)
13,328
12,406
11,475
13,812
13,120
12,084
11,875
13,948
15,219
13,099
11,909
13,413
13,914
13.104
Moisture
(%)
22.00
19.38
29.24
18.65
19.71
31.77
28.32
20.97
19.92
25.61
25.10
20.82
20.92
20.05
Ash
(%)
11.12
17.44
21.38
15.24
17.99
19.39
15.61
13.74
19.48
13.55
22.52
18.25
18.77
13.76
Volatile
matter
(%)
57.54
58.21
48.56
59.21
56.69
46.57
52.48
57.22
55.55
54.56
51.12
56.16
54.99
56.32
Fixed
carbon
(%)
9.34
4.97
0.82
6.90
5.61
2.27
3.59
8.07
5.05
6.38
1.26
4.77
5.32
4.87
Carbon
a)
32.58
32.27
28.36
33.59
32.41
27.98
29.41
33.90
32.66
31.33
26.57
30.23
31.03
29.72
Hydrogen
(7.)
4.91
4.36
4.21
4.61
4.88
4.64
4.98
5.08
4.96
4.68
4.20
5.08
4.95
5.18
Oxygen
a)
28.32
25.40
15.84
27.14
24.02
14.92
19.94
25.21
21.99
24.00
20.51
24.56
23.38
25.10
Sulfur
(%)
0.46
0.60
0.23
0.29
0.33
0.64
0.88
0.60
0.44
0.30
0.27
0.29
0.36
0.26
Chlorine
(7.)
0.25
0.26
0.20
0.16
0.17
0.25
0.22
0.14
0.21
0.20
0.26
0.32
0.19
0.59
Nitrogen
(%;
0.36
0.29
0.54
0.32
0.49
0.41
0.64
0.36
0.34
0.33
0.57
0.45
0.40
0.34
Mean
128.3
13,050 23.03
17.37 54.65
4.94
30.86
4.77
22.88 0.43
0.24
0.42
-------
TABLE 10. SIZE DISTRIBUTION OF RDF DISCHARGED FROM THE STORAGE BIN
(As received, all percents by weight)
Size (mm) standard ASTM E-ll designation
Sample No.
(test day)
22/
-£/
8
9
10
11
12
13
14
Mean£/
% Larger than
63
1.4
3.2
0.8
1.2
0
1.1
3.3
3.8
0.1
1.7
63
98.6
96.8
99.3
98.8
100.0
98.9
96.7
96.2
99.9
98.4
% Smaller than
38.1
79.9
85.2
88.5
93.9
91.1
93.2
89.0
84.3
95.1
88.9
19.0
18.7
65.5
67.7
81.5
75.8
71.0
73.3
66.2
68.9
65.4
9.5
14.5
38.2
40.4 *
58.1
58.0
48.6
50.9
41.5
38.4
43.2
4.8
10.3
22.2
22.5
35.1
28.6
26.5
23.3
24.5
25.3
24.3
Geometric
Mean
diameter
22.6
12.4
11.7
8.4
9.2
10.2
10.5
12.0
11.1
12.0
Standard
deviation
2.17
2.56
2.46
2.36
2.42
2.42
2.47
2.64
2.3.5
2.42
a/ Single stage shredding due to second stage shredder out of service because of bearing failure.
Second stage shredder not back in service until March 28, 1976.
b/ Extra sample taken April 22, 1976.
c/ Mean does not include single stage shredding data from March 23, 1976.
Note: First stage shredder grate size - 229 x 229 mm (9 x 9 in.).
Second stage shredder grate size - 76 x 127 mm (3 x 5 in.).
-------
TABLE 11. LABORATORY ANALYSIS OF RDF ASH (Ash of RDF discharged from
the storage bin ASTM Method D2795 (% by wt))
Sample No.
(test day)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Si02
42.54
41.82
49.95
46.80
50.20
51.60
44.25
54.10
54.00
43.22
51.41
49.18
48.27
47.32
11.90
13.53
10.20
13.30
11.70
11.60
10.40
8.45
11.30
18.17
9.39
11.61
11.73
11.20
Fe203
3.91
2.99
8.13
3.69
3.93
3.76
3.65
4.46
4.45
3.46
2.91
4.28
4.57
5.90
Ti02
1.42
1.76
1.11
1.41
1.68
1.67
1.20
1.07
1.35
1.30
1.28
1.47
1.55
1.96
P205
1.12
0.99
0.66
0.52
0.70
0.28
0.78
0.36
0.96
0.88
0.73
1.25
0.99
0.85
CaO
14.75
15.48
11.60
12.90
12.90
11.80
15.30
11.90
10.45
10.40
13.72
12.14
12.52
12.02
MgO
2.49
2.26
3.19
2.55
2.19
2.18
1.95
2.46
2.13
2.04
2.57
2.63
2.37
2.30
Na20
4.83
3.68
3.46
3.88
3.90
4.60
3.73
5.08
4.19
4.07
5.22
4.86
4.59
5.13
K20
1.70
1.52
2.16
1.64
1.57
1.73
1.54
1.65
1.87
2.26
1.67
2.10
2.04
1.75
Mean
48.19
11.75
4.29
1.45
0.79
12.71
2.38
4.37
1.80
-------
TABLE 12. FUSION TEMPERATURE OF RDF ASH
(Ash of RDF discharge from
Atlas bin)
Temperature (°C)
Sample No*
(test day)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Reducing atmosphere
IT
1110
1121
1127
1132
1127
1127
1127
1154
1149
1038
1032
1038
1121
1082
ST
1116
1127
1138
1143
1138
1132
1132
1171
1160
1138
1154
1166
1166
1116
HT
1121
1132
1143
1154
1149
1138
1138
1199
1171
1176
1176
1188
1182
1149
FT
1127
1138
1149
1160
1160
1143
1143
1249
1182
1210
1204
1221
1216
1182
Oxidizing atmosphere
IT
1121
1132
1149
1143
1138
1138
1138
1171
1166
1149
1166
1182
1188
1104
ST
1127
1138
1154
1154
1149
1143
1143
1204
1193
1193
1188
1204
1193
1132
HT
1132
1143
1160
1166
1160
1149
1149
1238
1210
1216
1210
1227
1221
1149
FT
1138
1149
1166
1171
1171
1154
1154
1282
1227
1243
1227
1249
1232
1188
Mean
1106
1143
1158
1177
1149
1165
1181
1197
ASTM Method D-1857
Nomenclature
IT = Initial deformation temperature
ST = Softening temperature (H = W)
W\
HT = Hemispherical temperature (H = -r)
FT = Fluid temperature
H = Gone height
W = Gone width
43
-------
Variability of Results
As expected there was considerable variation from day to day in the sam-
ple results. Table 13 is the range of data (maximum and minimum values) en-
countered, as well as the mean or average value and the standard deviation and
confidence interval for the complete spectrums of constituents (i.e., bulk
density, proximate analysis, etc.).
Also listed is the total number of samples in the mean and the standard
deviation. The coefficient of variation was also calculated. Coefficient of
variation (GV) is a measure of variability because it expresses the standard
deviation as a percent of the mean. As the absolute value of one characteris-
tic increases over that of a different characteristic, the standard deviation
may also increase.
A larger standard deviation does not necessarily mean larger variability,
and thus GV is a method of accommodating this restriction. The formula for
CV is as follows:
Sx
CV (%) =— (100)
where X — mean, and
S__ = standard deviation.
X
An analysis of Table 6 shows that the variability expressed as CV often
becomes quite high when the mean values are very low, such as sulfur, chlorine,
nitrogen, ash P2^5» an(* sc^een size larger than 63 mm.
In ranking analysis constituents on a basis of the least to the highest-
variability, the coefficient of variation is as follows:
RANKING - LOWEST TO HIGHEST VARIABILITY
- RDF ash
Volatile matter (smallest SiC>2 (smallest
variability) variability)
Hydrogen CaO
Carbon MgO
Heating value KjO
Geometric mean particle
diameter
Bulk density
Oxygen F«2°3
Ash P2<")5 (highest vari
Moisture ability)
Nitrogen
Sulfur
Chlorine
Fixed carbon
Particle size larger than
63 mm (highest vari-
ability)
44
-------
TABLE 13. VARIABILITY OF DAILY VALUES OF CHARACTERISTICS OF RDF
DISCHARGED FROM STORAGE BIN (As received all percents
by weight)
Range
Item
Analysis of RPF
Bulk density (kg/m3)
Heating value (kj/kg)
Moisture (%)
Ash (%)
Volatile matter (7.)
Fixed carbon (")
Carbon (%)
Hydrogen (%)
Oxygen (%)
Sulfur (7.)
Chlorine (7.)
Nitrogen (X)
Particle size
Geometric mean diameter anr
Percent larger than 63 nm
Analysis of RDF ash
Si02 (%)
A1203 (7.)
Fe203 CO
Ti02 (%)
P20; (7.)
CaO (7.)
MgO (%)
Na20 (7.)
K20 (7.)
Maximum
value
157.0
15,219
31.77
22.52
59.21
9.34
33.90
5.18
28.32
0.88
0.59
0.64
12.4
3.8
54.10
18.17
8.13
1.96
1.25
15.48
3.19
5.22
2.26
Minimum
value
97.0
11,475
18.65
11.12
46.57
0.82
26.57
4.20
14.92
0.23
0.14
0.29
8.4
0
41.82
8.45
2.91
1.07
0.28
10.40
1.95
3.46
1.52
X
Mean
128.3
13,050
23.03
17.37
54.65
4.95
30.86
4.77
22.88
0.43
0.24
0.42
12.0
1.7
48.19
11.75
4.29
1.45
0.79
12.71
2.38
4.37
1.80
n
number
of
samples
14
14
14
14
14
14
14
14
14
14
14
14
8
9
14
14
14
14
14
14
14
14
14
• Sx
standard
deviation
18.14
1021.6
4.212
3.170
3.702
2.405
2.224
0.324
3.903
0.190
0.110
0.106
1.392
1.421
4.059
2.288
1.332
0.256
0.276
1.608
0.312
0.598
0.244
Variability
about the
mean
at 957.
confidence
coefficient
10.5
589.8
2.43
1.83
2.14
1.39
1.28
0.19
2.25
0.11
0.06
0.06
1.2
1.1
2.34
1.32
7.69
0.15
0.16
0.93
0.18
0.35
0.14
CV
coefficient
of variation
(%)
14.1
7.83
18.29
18.25
6.77
48.64
7.21
6.79
17.06
44.77
45.12
25.44
13.02
85.85
8.42
19.47
31.04
17.74
34.86
12.66
13.10
13.68
13.56
Fusion temperature of RDF ash -°C
Seducing atmosphere
Initial deformation
Softening (ST)
Hemispherical
Fluid
Oxidizing atmosphere
Initial deformation
Softening
Hemispherical
Fluid
(IT)
(ST)
(HT)
(FT)
(IT)
(ST)
(HT)
(FT)
1154
1171
1199
1249
1188
1204
1238
1282
1032
1116
1121
1127
1104
1127
1132
1138
1106
1143
1158
1177
1149
1165
1181
1197
14
14
14
14
14
14
14
14
41.
18.
23.
37.
23.
28.
37.
45.
47
15
57
42
48
62
10
53
72
31
41
65
41
50
64
79
3.
1.
2.
3.
2.
2.
3.
3.
75
59
04
18
04
46
14
80
a/ Particle size does not include high value on March 23, 1975, due to single stage shredding.
45
-------
Comparison to Daily Samples Taken by the City of Ames
Various comparisons can be made of these 14 daily samples to the City of
Ames daily results of RDF moisture and heating value discussed in the preceding
section*
A statistical treatment of the data compared the mean value of the 14
daily samples to the mean value of 286 daily samples taken by the City of Ames
for the year 1976. There was no statistically significant difference at the
95% confidence level in these mean values of moisture and heating value as
shown below:
As-received
Moisture (%) heating value
by weight (kj/kg)
Standard Mean Standard
deviation value deviation
14 Daily samples 23.03 4.212 13,050 1,021.6
286 Daily samples over 22.23 4.864 13,188 1,297.2
year 1976
% Difference (14 samples 3.6 1.1
versus 286 samples)
Comparison of Ames and St. Louis RDF
The preceding section discussed the RDF heating value and moisture content
data determined for RDF at St. Louis. Bulk density, proximate and ultimate
analysis and screen size were also determined for RDF produced at St. Louis.
A comparison of all of these values between St. Louis RDF and the 14 daily
samples of Ames RDF was made.
Table 14 shows one of the very important conclusions of the statistical
analysis of the data. The Statistical F Test was employed to compare the vari-
ability of RDF between Ames and St. Louis. The results are shown in Table 8.
There is no statistically significant difference in variability about the mean
except for percent sulfur. This is an important conclusion which could affect
future material sampling programs at refuse processing plants. Ninety-seven
daily samples of RDF produced at St. Louis were analyzed for proximate and
ultimate analysis, screen, size, metals by chemical analysis, and composition
by visual means, and 10 samples were analyzed for bulk density. Therefore,
the daily variability is well known. This variability apparently does not
differ between these two plants, at least for the comparisons that could be
46
-------
TABLE 14. TEST OF SIGNIFICANT DIFFERENCE IN VARIABILITY BETWEEN DAILY SAMPLES
OF RDF PRODUCED AT AMES AND ST. LOUIS
Item
Analysis of RDF
Bulk density (kg/m3)
Heating value (kj/kg)
Moisture (%)
Ash (%)
Volatile matter (%)
Fixed carbon (%)
Carbon (%)
Hydrogen (%)
Oxygen (%)
Sulfur (%)
Nitrogen (%)
Particle size
Geometric mean diameter (mm)
n Number
of samples
Ames St. Louis
14
14
14
14
14
14
14
14
14
14
14
8
10
97
97
97
97
97
97
97
97
97
97
97
Sx
Standard
deviation
Ames St
18.14
1,021.6 1,
4.21
3.17
3.70
2.41
2.22
0.32
3.90
0.19
0.11
1.39
« Louis
12.9
370.3
7.28
4.61
5.07
4.13
2.75
0.46
3.68
0.06
0.08
1.87
Variance
ratio K
(Sxf/Sxi)
1.98
1.80
3.00
2.11
1.88
2.94
1.53
2.07
1.12
10.03
1.89
1.81
Significant difference
in sample variability^/
No
No
No
No
No
No
No
No
No
Yes
No
No
a/ Snedecor, G. W., and W. G.
Cochran,
Statistical Methods
, 6th edition, Iowa State
University
Press, Ames, Iowa.
F at 99% = 3.27 for nx = 97, n2 = 14 (99% = 1 - a)
F at 99% = 5.75 for KI = 97, n2 = 8
No significant difference if F ^ FQ.QI
-------
made, including bulk density, proximate and ultimate analysis, and mean par-
ticle size.
The variability in sulfur content was lower at St. Louis than at Ames
but the reasons for this lower variability are at present unknown.
A comparison of mean values between Ames and St. Louis is presented in
Table 15. A statistical analysis was next used to determine if any differ-
ence between means exists. Since there was no significant difference in
variability, a pooled standard deviation was calculated and the difference
between means examined using the t-distribution for all items except sulfur.
Because there was a significant difference in variability between Ames and
St. Louis for sulfur, the standard t test could not be used. For sulfur, the
treatment developed by Welch as reported by Brownleel/ was used to test for a
significant difference between means.
The statistical analyses of these comparisons showed that at the 95% con-
fidence level, there was a statistically significant difference between Ames
and St. Louis mean values of RDF characteristics except for bulk density and
oxygen content, which had no statistically significant difference between
means. The conclusions from this comparison are as follows:
Ames values higher than Ames values lower
.St. Louis than St. Louis
Heating value Moisture
Volatile matter Ash
Carbon Fixed carbon
Hydrogen Nitrogen
Sulfur
Geometric mean
Diameter particle size
The Ames RDF samples are of the discharge of the storage bin while the
St. Louis RDF is that entering a storage bin, except for bulk density. Ninety-
seven samples of RDF entering a storage bin were taken at St. Louis and analyzed
for many items including bulk density. However, because of the compressibility
or packing factor, RDF bulk density is higher leaving a storage bin. Therefore,
bulk density of RDF leaving the storage bin at St. Louis was used for a valid
comparison to the Ames RDF. Unfortunately, only 10 samples were taken of RDF
leaving the St. Louis storage bin.
I/Brownlee, K. A.Statistical Theory and Methodology in Science and
"~ Engineering. John Wiley and Sons, New York, 1965.
48
-------
TABLE 15. COMPARISON OF AMES AND ST. LOUIS MEAN VALUES OF DAILY SAMPLES OF RDF
(Number of samples: St. Louis - 97 except 10 for bulk density*
Ames - 14 except 8 for particle size.) (Results as received, all 7,
by weight.)
Item
Analysis of RDF
Bulk density (kg/m3)
Heating value (kj/kg)
Moisture (%)
Ash (%)
Volatile matter (%)
Fixed carbon (%)
Carbon (%)
Hydrogen (%)
Oxygen (%)
Sulfur 00
Chlorine (%)
Nitrogen (%)
Particle size
geometric mean diameter (mm)
Ames
128.3
13,050
23.03
17.37
54.65
4.94
30.86
4.77
22.88
0.43
0.24
0.42
10.7
Mean values
St. Louis
130.1
10,636
26.60
21.70
43.60
8.10
26.00
3.79
21.20
0.18
a/
0.53
7.4
% Difference
(Ames versus St. Louis)
- 1.4
+ 22.7
- 13.4
- 20.0
+ 25.3
- 39.0
+ 18.7
+ 25.9
+ 7.9
+138.9
a/
- 20.8
+ 44.6
a/ Chlorine not determined during St. Louis tests.
-------
There is an expected, but important, relationship of increasing heating
value with decreasing moisture and ash content. Therefore, heating value of
RDF was calculated on both a moisture free and a moisture and ash free basis.
The statistical standard deviation Sx and the coefficient of variation
(CV) were calculated for the daily sample data to determine if variability
of RDF heating value changes when expressed on a moisture free or moisture
and ash free basis. Table 16 shows the results of these calculations. Vari-
ability as expressed by CV had only one definite trend. The CV for heating
value was substantially less than for moisture and ash.
Figure 17 shows the relationship between heating balue and moisture con-
tent and ash content. There was a 71% correlation between heating value and
moisture. There was not a good statistical percentage correlation between
heating value and ash content due to the scatter in the data.
Figure 17 shows that the Ames RDF heating value is inherently higher
than what was observed during the St. Louis tests. The boiler sees RDF heat-
ing value as is, with the moisture and ash content that is actually present.
The higher as-received heating value at Ames is not entirely due to lower
moisture and ash content. The heating value of the combustibles (moisture
and ash free heating value) in the Ames RDF is also higher than the St. Louis
RDF. The reasons for this may be answered when processing plant tests are
conducted and an analysis for RDF or percent paper, plastic, etc., is con-
ducted.
50
-------
TABLE 16. MOISTURE FREE AND ASH FREE VALUES OF DAILY SAMPLES OF
RDF DISCHARGED FROM THE STORAGE BIN (All percents
by weight)
Sample No*
(test day)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
^^^•»
n
y
Sx
cv %
Moisture
% as
received
22.00
19.38
29.24
18.65
19.71
31.77
28.32
20.97
19.92
25.61
25.10
20.82
20.92
20.05
14
23.03
4.212
18.29
Ash
As
received
11.12
17.44
21.38
15.24
17.99
19.39
15.61
13.74
19.48
13.55
22.52
18.25
18.77
18.76
14
17.37
3.170
18.25
7
to
Moisture
free
14.26
21.63
30.21
18.73
22.41
28.42
21.78
17.39
24.33
18.21
30.07
23.05
23.74
23.46
14
22.69
4.685
20.64
Heating value (kj/kg)
As Moisture Moisture and
received free ash free
13,328
12,406
11,475
13,812
13,120
12,084
11,875
13,948
15,219
13,099
11.909
13,413
13,914
13,104
14
13,050
1,021.6
7.83
17,087
15,388
16,217
16,978
16,341
17,711
16,567
17,649
19,005
17,609
15,900
16,940
17,595
16,390
14
16,956
922.8
5.44
19,929
19,635
23,237
20,891
21,061
24,743
21,180
21,364
25,116
21,530
22.737
22,014
23,072
21,414
14
21,995
1,619.4
7.36
51
-------
22,000 r.
Average of Moisture &
Ash Free Heating Values
Ames RDF Best Fit Curve
-kj/kg = 21,995- 227. 1 (% Moisture Free Ash)
St. Louis RDF
Best Fit Curve
10
15 20
% ASH (Moisture Free)
25
30
35
<
_*
18,000 T
16,000
14,000
> < 12,000
a""
z
10,000
Average of Moisture Free Heating Values
Ames RDF Best Fit Curve
71% Correlation
= 17,002 - 171.6 (% Moisture)
•^ •
St. Louis RDF
Best Fit Curve •
I
10
15 20
% MOISTURE
25
30
35
Figure 17. Heating value of refuse derived fuel (RDF) versus moisture
and ash content for daily samples.
52
-------
SECTION 6
REFUSE PROCESSING PLANT EQUIPMENT AND FACILITY EVALUATIONS
This section of the report provides an operating history of the Ames
solid waste processing plant from a technical point of view, that is, as dif-
ferentiated from an economic viewpoint. It is divided into eight parts as
follows:
Plant start-up experience - A summary of plant operations. The actual
daily log is included as Appendix Table C-l.
Refuse received - A summary of volumes, types and methods by which refuse
is delivered to the processing plant. Refuse delivered by private vehicles
is shown in Appendix Table C-2.
Plant labor - Operating history of the labor segment of the plant opera-
tion. A job description of the plant labor force is contained in Appendix
Table C-3.
Processing hours - A summary of the operating hours and downtime of the
plant and an assessment of plant utilization. Daily operating data are in-
cluded as Appendix Table C-4.
Plant electric power consumption - A summary of electric power consump-
tion for the processing plant. Weekly data are presented in Appendix Table
C-5.
Refuse derived fuel (RDF) conveying and storage - This part of the re-
port is separated from the rest of the material because it involves the sub-
system which transports processed refuse from the plant to the Ames electric
generating plant. The information presented here provides operating experi-
ence of this part of the operation.
Figure 18, supplied by Henningson, Durham and Richardson, Consulting
Engineers, who designed the plant, shows a layout of the refuse processing
plant to provide the reader with a conceptual idea of the various subsystems
of the plant. Essentially, raw refuse first enters the plant system via in-
feed Conveyor C-l into the first stage shredder, then, via Conveyor C-3
53
-------
£f" u '|f -^—
' LOW DI*GPAM
^PABAflON
Figure 18. Refuse processing plant flow diagram, City of Ames, Iowa.
-------
through the second stage shredder. A magnetic belt separator removes ferrous
metal from the material flow-stream between the first and second stage shredder.
Conveyor C-6 transports the material from the second stage shredder into the
air density separation subsystem. Light material is transported via a pneuma-
tic conveying system to a storage bin prior to transport to the electric power
generating plant. The heavy material drops out of the air density separator
onto conveying belts where it is transported through a series of magnetic pulley
separators, a trommel screen and an electrical eddy current nonferrous metal
separation system. In this process, the material is segregated into glass,
aluminum metal, other nonferrous metal, ferrous metal and oversized material
that is rerouted back through the system.
REFUSE PROCESSING PLANT ACTIVITY
This section contains a description of the major events which occurred at
the refuse processing plant, including those prior to the actual beginning of
this study (June 1, 1976), and extending through December 31, 1976. Even
though the EPA grant investigations did not include the time prior to June 1,
the start-up period for the processing plant may be important for other similar
plants, since there is very little information available in the literature con-
cerning refuse plant start-up experience. A review of the activities since the
plant began operating (August 30, 1975) is a valuable addition to the litera-
ture. Since June 1, 1976, a daily activity log has been maintained; this is
included as Appendix Table C-l.
The following discussion of operating experience at the Ames plant is
presented in 11 categories. Typically, the plant has operated on one 8-hr
shift per day, 5 days per week. A schedule of these operating hours is presented
in Table 17. A work shift strictly for maintenenace and repair was insti-
tuted in September 1976 from 2 p.m. until 10:30 p.m., Monday through Friday.
The work crew consists of four people. Consequently, the operating hours and
one shift are not an exact description.
Shredder
On August 30, 1975, the first refuse was fed through the plant. Approxi-
mately 2 Mg was fed through the system at a very slow rate of only 9 Mg/hr (10
ton/hr). This procedure was to ensure that the various components of the sys-
tem actually functioned. All equipment performed satisfactorily. Although
minor spillage was noticed, it was not judged to be a major problem. Normal
manual cleanup procedures could accommodate the spillage.
This successful first day's operation was then followed by the production
amounts shown below for 4 months in 1975.
55
-------
Ul
TABLE 17. PROCESSING PLANT DAILY OPERATING HOURS, JUNE - DECEMBER 1976
(Plant operating hours include the elapsed time between
plant start-up and plant shutdown for the day.)
Hours by month
Day
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
June
9.3
7.9
11.0
9.6
0
0
4.5
6.7
6.3
7.1
7.5
0
0
0
7.6
0
6.7
0
3.9
0
2.1
2.8
3.7
4.4
4.0
July
8.2
8.5
0
0
0
8.3
4.7
4.9
5.4
0
0
5.1
8.1
6.0
7.0
6.1
0
0
4.8
7.0
7.0
5.6
4.3
0
0
August
0
0.7
2.7
11.7
10.9
10.5
0
0
7.1
6.7
4.2
10.4
7.4
0
0
7.8
7.0
0
10.6
3.5
0
0
9.5
11.3
3.7
September
0
9.8
12.3
0
0
0
0
3.1
10.0
13.8
0
0
8.5
3.4
10.0
9.8
7.9
0
0
8.8
7.5
6.0
7.5
6.1
0
(continued)
October
9.6
0
0
8.3
7.3
3.6
8.7
9.0
0
0
7.0
8.4
7.6
4.9
6.7
0
0
8.2
5.8
7.5
5.5
7.5
0
0
8.4
November*?/
7.6
9.3
7.1
7.1
8.5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3.8
2.0
8.1
0
December
10.0
8.6
8.2
0
0
6.7
9.0
3.6
8.3
6.1
0
0
7.4
8.1
3.0
8.9
6.5
0
0
12.7
9.2
5.3
7.2
3.3
0
-------
TABLE 17. (continued)
VMI«MMaiVHM^»a^V«MHMB^^^
Day
26
27
28
29
30
31
Totals
Avg./day
^BMHaHHHBIIIHBI^HHIVtHHIIIBVBIBBIBHnBv^HH
June
0
0
8.7
6.4
5.0
_
125.2
6.3
••••••V*MHIVHIIIBIWHB^HIV^*allBMriqH«*4lfl|lm
July
7.0
8.5
3.4
5.7
8.0
0
133.6
6.4
V^^BM^MMWVlaMtflMIIV^kM^^^alHIHMI
August
6.5
5.5
0
0
8.5
11.2
157.4
7.5
Hours by month
September
0
7.0
5.5
2.8
1.4
-
148.2
7.8
^^•HIH(B-(IHM^^HII«WIIII^HH«*IIIIIIIBIV^I*l>«^-VVW«VIIIIIIII^HIII
October
4.8
4.8
7.1
1.3
0
0
142.0
6.8
i i
November—'
7.4
0
0
6.6
9.5
-
77.0
7.7
-J-TT-----
December
0
5.6
7.5
6.2
6.0
5.7
163.1
7.1
Ui
a/ Does not include 10 days of cleanup and repair work resulting from November 6 fire damage.
-------
Month Raw refuse processed
(1975) (Mg) (tons)
August 30 1.8 (2)
September 513 (565)
October 1,529 (1,685)
November 1,712 (1,887)
December 2,647 (2,918)
During the first 5 months of operation the average maximum processing
rate was only 23 to 32 Mg/hr of actual processing time (25 to 35 tons/hr). The
desired and planned-for production rate is 45 Mg/hr (50 tons/hr).
The first stage shredder performed well. However, when a processing rate
of 23 Mg/hr was exceeded, the second stage shredder experienced motor current
surging, by which periodically a high amperage draw occurred for a few moments.
Once during this period, the amperage was high enough for a long enough period
of time that the motor overload circuit cut the electric power to the shredder
motor. Thus, the second stage shredder was identified as a potential restric-
tion to faster processing rates.
Shredder specifications during this 5-month period were as follows:
Weight of
each
Shredder No. of hammer Grate size
(stage) hammers kg^ (Ib) mm (in.)
1 48 69 (152) 229 sq (9 sq)
2 96 24 (52) 67 x 76 (2-5/8 x 3)
Because the first stage shredder worked well, the first conclusion was
that the second stage shredder grate size was too small. Each grate opening
was separated from the next grate opening by a 25.4 mm (1 in.) grate bar. In
late January 1976, on one-fourth of the grates, every other bar was removed,
resulting in 67 x 178 mm (2-5/8 x 7 in.) openings. This resulted in some im-
provement in shredder performance but not enough to reach the desired 42 Mg/hr.
Next, it was hypothesized that the shredder was volume limited. Due to
the low bulk density of the refuse, it was thought there was not enough space
inside the shredder to accommodate the desired volume of refuse. Therefore,
early in February 1976, one-half of the hammers were removed. This also showed
some improvement in shredder performance but again the desired processing rate
was not achieved.
58
-------
In February 1976, new grates purchased from the factory were installed.
These grates were 76 x 127 ran (3 x 5 in.). These new grates plus using only
48 hammers instead of the original 96, increased the shredder rate to 45 Mg/hr
(50 tons/hr) without excessive motor amperage surging. The effect on particle
size is not known because no particle size measurements were made at this time.
Shredder specifications following this modification became:
Weight of
Shredder No. of each hammer _ Grate size
(stage) hammers k£ (lb) mm (jn.)
1 (unchanged) 48 69 (152) 229 sq (9 sq)
2 48 24 (52) 76 x 127 (3 x 5)
Because the system worked well, it was left as is, and the new grates were
not operated with the original 96 hammers installed. Therefore, it is not known
what the shredder performance would be with 96 hammers and 76 x 127 mm grates.
The plant personnel have found through experience that by allowing the ham-
mers to wear down and increasing the clearance between the hammer and the grate,
motor current surging is reduced. Secondly, it has been observed (although not
verified by detailed tests) that the kilowatt hour per megagram of refuse pro-
cessed is also reduced when the hammers are allowed to wear down. This situ-
ation is the opposite of the St. Louis experience where it was accepted that
the hammers must constantly be retipped and hardfaced to build up the material
worn away from the hammer face.
The Ames plant is not a research pilot plant, but a commercial facility.
There was a desire by the city personnel to achieve good production rates.
Therefore, once this goal was reached, there was no need to experiment further
with the shredders. The result is that no information was recorded concerning
the effect of hammer wear on RDF size and quality and plant operating costs.
The only implication in this discussion is that increased clearance between the
hammers and the grate resulted in a smoother operating shredder. The effects
on other operations in the system such as metal separation and air classifica-
tion are unknown.
Literature is available on shredding municipal solid waste.i' However,
the area of shredder internal volume, grate size,number of hammers, and ref-
use bulk density appears to be a desirable field of investigation for future
work a± Ames.
If Ananth, K. P., and J. Shum. "Fine Shredding of Municipal Solid Waste."
EPA-600/2-76-208, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina 27711, July 1976.
59
-------
Another problem on the second stage shredder was the fan effect (windage)
caused by the hammers, which flow material out of the in-feed chute* This
situation was improved by welding steel plates on the back side of the shredder
throat, thereby reducing the clearance between the hammers and the shredder
housing.
Information on shredder maintenance is presented in a later section en-
titled "Other Plant Evaluations."
Shredder Bearing Failure
The only major shredder maintenance item that has occurred to date was
failure of one of the second stage shredder bearings in early March 1976. This
was caused by breakage of the bearing oil sump sight glass. The broken sight
glass resulted in rapid drainage of oil from the sump and subsequent bearing
failure. The shredder was out of operation for 2-1/2 weeks because the bear-
ing failure had scored the shaft. The shaft had to be built up and turned
down before the new bearing could be installed. However, the refuse processing
plant was out of service for only 2 days. Plant operations continued by plac-
ing some of the second stage shredder grates in the first stage shredder and
operating the plant with one shredder. The plant did not perform well with
single stage shredding, but it was able to continue operating. The single
stage shredding described above resulted in approximately twice as large a
mean particle size of RDF. The mean RDF particle diameter for the normal
double stage shredding was 12.0 mm versus 22.6 mm for single stage shredding
(Table 4 in preceding section). This large particle size tended to cause plug-
gage of the plant material hauling equipment.
Fire in the Shredders
At 3:15 p.m., on July 12, 1976, a fire occurred in the shredders. It is
theorized that at least 19 liters (5 gal.) of gasoline in glass or easily
breakable containers entered the first stage shredder undetected and a spark
from the hammers striking metal in the refuse caused ignition.
In any event, what is known is that flames shot upward out of the first-
stage shredder in-feed opening and set off the sprinklers and fire alarm in
the raw refuse receiving area. Flames then traveled along the conveyor belt
from the first stage shredder to the second stage shredder.
No damage was done other than shutting down the processing plant for the
balance of the work day. The fire was considered dead by 5:30 p.m. The pad
of the refuse on the rubber conveyor belt prevented it from being burned and
no damage was done to the shredders.
60
-------
Even though flames were present in the enclosed processing area, no dust
explosion or flash fire occurred due to suspended particulates in the process-
ing plant atmosphere. Processing commenced at 10:10 a.m., the next day, July
13, 1976.
In-Feed Conveyor for the First Stage Shredder
The raw refuse from the receiving floor is fed to the first stage shredder
by a Z pan conveyor. The drop height from the in-feed conveyor to the shredder
is approximately 1 m. Some material is thrown back out of the shredder feed
opening, caught on the return section of the conveyor and dragged out of the
shredder.
This problem was solved by building a metal chute termed a "dribble chute"
to catch this material and route it to the vibrating pan receiving conveyor un-
derneath the shredder.
A second problem that occurs is that long metal parts such as metal rods
and shafts are sometimes thrown back out of the shredder in-feed opening. If
these are caught in the hinge section of the Z pan conveyor, the conveyor be-
comes jammed. No solution has yet been found for this problem, and it remains
one of the most frequent causes of downtime.
Vibrating Pan Conveyors
Generally, the plant personnel feel that all the vibrating conveyors are
undersized for 45 Mg/hr (50 tons/hr).
The height of the discharge opening from the first stage shredder to the
receiving vibrating conveyor was increased 76 mm (3 in.) to allow a thicker
depth of shredded refuse on the conveyor to achieve 45 Mg/hr flow rate.
Air Density Separator (ADS)
Air Separation Chamber (See Figure 19)—
At first a zig-zag or Z-shaped adjustable throat chamber arrangement was
tried, but this did not prove successful. The manufacturer adjusted the throat
dimension, resulting in a straight-walled, wedge-shaped throat area.
There was still too much oversized or heavy material in the light fraction
(RDF). It was determined that some material was not falling straight down out
of the rotary airlock but was being thrown out with a horizontal component of
velocity. This allowed some shredded refuse to be picked up by the upward
moving airstream before the material could enter the adjustable throat separa-
tion chamber (see Figure 20).
61
-------
Hinge Points'
Figure 19. Air separation chamber.
62
-------
ADDED
BRPFLE
Hinge Points'
Figure 20. Modification to air separation chamber.
63
-------
The problem was solved by installing a 254-mm (10-int) long baffle at the
exit of the airlock (see Figure 20), This prevented any shredded refuse from
being thrown with a horizontal component of direction, and ensured that all
material fell downward before entering the air stream.
Air Flow Adjustment—
The ADS air flow is usually manually adjusted several times each week,
especially in rainy weather. Dampness tends to affect the ADS performance, re-
quiring air flow adjustment to maintain the same efficiency.
The ADS air flow is adjusted until small amounts of paper appear in the
ADS heavies. This criterion is based on the theory that small amounts of
paper in the heavies mean the minimum amount of noncombustibles are contained
in the lights (RDF).
Metal Fatigue Failure—
Shredded refuse is fed to the ADS rotary airlock and air separation cham-
ber by a vibrating pan feeder. Some vibration from this vibrating feeder is
transmitted to the rest of the ADS equipment. Some metal plates failed due to
metal fatigue and had to be reinforced.
Surge Bin Dust Emissions—
The ADS drag conveyor has a surge bin ahead of the drag conveyor to receive
material from a belt conveyor leading from the second stage shredder (see Figure
21).
This surge bin was installed with the top open. Shredded refuse falling
from the belt conveyor discharge to the bottom of the surge bin caused heavy
dust emissions from the surge bin top. Fine dust particles were dislodged
from the shredded refuse due to the impact of the refuse on the bottom of the
surge bin and also the impact on the refuse already in the bin.
C. L/JL11 ClllU CU- k?VS L.J.1C J-IU£/C**—1_ Wil 1.J.IC JL C*. U>?C Cl.LJ_ CdVJ-jr J-ll (.J.LC U JLtl 9
This problem was solved by covering the surge bin top with
_ »_ • _ W _ _ J T> 1 .
canvas.
Vibrating Feeder Pluggage--
The vibrating pan conveyor feeding shredded refuse to the ADS air separa-
tion chamber receives material from the ADS drag chain conveyor (see Figure 21).
Design capacity of the ADS system is 41 Mg/hr (45 tons/hr). Actual Mg/hr
capacity of the vibrating feeder was not high enough,so that at high processing
rates, material built up between the vibrating feeder and the drag conveyor dis-
charge chute, plugging the drag conveyor. In early January 1976, this problem
was solved by installing a sloping steel plate in the vibrating pan bottom (see
Figure 22). This increased the effective slope of the conveyor and increased
the throughput capacity of the conveyor.
64
-------
Scalp
Belt Conveyor
from Second
Stage Shredder
Surge Bin-
Top Covered |
with Canvas
Lights to
Cyclone
Air
Separation
Chamber
Heavies
to Belt
Conveyor
Figure 21. Air density separator.
65
-------
Steel Plate
Installed to
Increase Slope
of Vibrating
Feeder I
Perforated
Metal Screen
Drag Conveyor
Discharge
To ADS
Fines to
ADS Heavies
Belt Conveyor
Figure 22. Air density separator feeder modification.
66
-------
Vibrating Feeder Screen Section Pluggage—
White goods such as stoves, refrigerators, etc., were normally stockpiled
on the raw refuse receiving floor and shredded at the end of the work shift.
The vibrating pan feeder has a perforated metal screen section to remove fine
particles from the shredded refuse (see Figure 22).
When white goods were shredded, small metal particles not separated out by
the magnetic belt separator would plug the perforated metal screen. This plug-
gage resulted in the bottom of the screen section of the pan having a rough,
irregular surface instead of a smooth surface as in the case of unplugged
holes. This rough surface caused shredded refuse to not slide along the vi-
brating pan. Instead, shredded refuse would build up on the pan and eventually
plug the ADS drag conveyor discharge chute.
The solution to this problem was more frequent cleaning of the vibrating
feeder screen. The screen is now cleaned every time after white goods are
shredded. Also, some stockpiled white goods are being sold, nonshredded, to a
metal scrap dealer, which reduces the percentage of white goods requiring shred-
ding in the plant.
Drag Chain Conveyor Scalping Roll Pluggage—
The ADS drag conveyor has a scalping roll whose function is to level off
and even out the volume of shredder refuse being pulled along by the drag chain.
This is done to ensure a feed rate as even as possible to the ADS air separation
chamber. The scalping roll is a round metal cylinder fitted with steel rods
projecting outward. These rods act as fingers to dig into and level out any in-
stantaneously large volume of refuse.
The problem is that long pieces of refuse such as rubber hose, nylon stock-
ings, plastic tape, etc., can pass lengthwise through the shredder grates.
Lengths in excess of 1 m often occur although their percentage in terms of
weight of RDF is small. These long materials tend to wrap around the metal
rods on the scalping roll, clogging up the roll, and making it ineffective.
Also, when clogged, the scalping roll motor becomes overloaded and the
motor overload circuit will disconnect the electrical power to the motor.
The only solution to this problem found to date is frequent manual clean-
ing of the scalping roll. Cleaning must be done at least once per week.
Drag Chain Breakage-
Eight times between start-up and the end of July 1976, the flights on the
drag chain have become bent and have broken loose from the chain on each side
of the conveyor. This jams the conveyor. The plant must then be shut down,
the drag conveyor cleaned out and new flights welded in place. The bottom re-
turn sprocket assembly and the chain take-up sprocket assembly were reversed in
67
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the original installation. This allowed shredded refuse to fall into the take-
up assembly, causing jamming and eventual chain breakage. In early August 1976,
the ADS system manufacturer installed new sprocket assemblies. Now, both the
return and take-up sprockets have solid cylindrical drums instead of the pre-
vious open sprocket and shaft. These drums prevent refuse from falling through
and clogging the take-up assembly. Plant personnel believe that this will al-
leviate drag chain breakage.
Cyclone Separator—
The separation efficiency of the ADS cyclone appears to be good based on
visual observations. Only a very small amount of particulate matter is ob-
served in the cyclone exhaust. The air intake filter for the pneumatic con-
veyor blower located adjacent to the cyclone exhaust has plugged only once
since the start of operations. Pluggage was due to large pieces of plastic
from plastic bags and wrapping material.
This cyclone exhaust is ducted back to the ADS air separation chamber
inlet so that a recirculating air flow exists and no air emissions to the
atmosphere occur. However, some dust from this recirculated cyclone exhaust
is blown out into the processing plant basement.
Plans are to build an enclosed room around this cyclone exhaust and air
separation air intake area, to prevent blowback into the rest of the process-
ing area.
Ferrous Metal Separation
The ferrous metal recovery system has worked reasonably well from the first
day of plant start-up. Although no sample data are presently available concern-
ing overall efficiency of the system, the plant personnel believe that over 90%
of the ferrous metal is picked up by the magnetic belt separator installed be-
tween the first and second stage shredders. The balance of the ferrous metal
is then removed by the belt conveyor magnetic head pulley and two belt conveyor
magnetic tail pulleys in the plant material handling system.
The only operational problem to date has been occasional clogging due to
mattress springs.
Aluminum Separation
The processing plant commenced operation on August 30, 1975. However, in-
stallation of the aluminum separation system was not completed until January
1976. At first, there were a series of material handling problems. Some of the
conveyor belts broke, and several vibrating pan conveyors and feed chutes had
pluggage problems. Some of these conditions have been corrected. However,
there remain problems of dissimilar metal corrosion, excessive cooling water
68
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usage because of lack of automatic cooling water flow controls, and material
catching between Conveyors C-22 and C-23.
A major end product problem is that other nonferrous material such as cop-
per, zinc, brass, etc., is also removed with the aluminum, resulting in a low
purity aluminum scrap product. The aluminum separation system manufacturer
and Alcoa are now working on this problem. Presently, consideration is being
given to an air separation system to further purify the aluminum scrap. Flat-
tened aluminum cans, for example, could be aerodynamically removed from the
heavier particles of copper, zinc, and brass.
As of the end of December 1976, the problem of the aluminum scrap by-
product has not been solved. Aluminum separation is still considered to be in
the start-up and shakedown mode.
Pneumatic Conveying Systems
Pneumatic Conveying from Processing Plant to Storage Bin--
This pneumatic line is 366 mm (14 in.) diameter in size and 213 m (700 ft)
long, containing two 60-degree elbows.
In October and November 1975, this line was plugged three times due to very
wet material entering the system. The pluggage could not be removed by the
usual "Roto-Rooter" technique used for cleaning clogged sewers. Instead a
"Sewer-Jet" was employed to clear the lines. A "Sewer-Jet" is a flexible hose
line pushed through the pneumatic conveying line to the plugged section and
water at approximately 4,100 kPa (600 psi) pressure ejected from the pipe tip.
This plugging problem has been solved by an operating procedure. Any
masses of wet material are spread out and mixed with the other refuse on the
raw refuse receiving floor by the front end loader operator. Therefore, the
wet material is distributed with normal moisture content refuse before it is
pushed onto the first stage shredder feed conveyor by the front end loader.
This procedure requires alertness by the front end loader operator.
Another problem was uneven RDF distribution into the rotary airlock feed-
ing RDF into the pneumatic conveying line. RDF is fed to the airlock by a
screw conveyor which drops the RDF into one side of the airlock. RDF would
then tend to build up on one side of the drop out portion. This condition was
eliminated by changing the sheave size on the blower supplying the pneumatic
conveying air on the basis of manufacturers' literature of blown air flow
versus RPM. This increased air flow by approximately 10%, eliminating the
uneven drop out problem. Although air velocities were not measured, the in-
creased air flow was eventually at a high enough velocity to pick up and carry
away the RDF, even though the distribution into the air stream from the air-
lock feeder was uneven.
69
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Pneumatic Conveyor Line Elbows--
All the pneumatic lines, both from the refuse processing plant to the
Atlas bin and from the Atlas bin to the boilers were installed with replace-
able wear back liners in the elbows. The first liners were ordinary mild
steel. Since start-up, all of the original steel liners have worn out. The
wear back liners are being replaced with higher wear resistant liners which
are giving much better performance. Both Astroloy and the GR 25 wear resist-
ance metal alloys have been used. The CR 25 alloy is currently showing good
wear resistance, but it is also the most expensive. It is too early to pre-
dict what will be the most cost effective liner at Ames. This will be deter-
mined as the plant gains more experience.
Various liner materials for pneumatic liner conveying RDF were tried by
the Union Electric Company during the St. Louis tests. The results of these
tests are reportedi/ and indicate that glass fiber reinforced epoxy resin
lined with alumina ceramic or R35 abrasion resistance cast metal were suit-
able materials to reduce elbow wear. However, the Astroloy and CR 25 mate-
rial being used at Ames were not tried at St. Louis and therefore no direct
comparisons can be made.
Pneumatic Conveying from Storage Bin to Boilers-
There are four lines from the Atlas bin to the boilers. These are 203 mm
(8 in.) diameter in size and an average 137 m (450 ft) long. Actual lengths
of the lines vary depending upon the boiler to which the pneumatic conveying
line is directed. The number of elbows varies from four to seven, depending
again upon which boiler is fed.
From start-up to the end of July 1976, a period of 11 months, approximately
200 pluggages have occurred. This is an average of nearly once per day. Plug-
gage occurs both in the pneumatic conveying lines and the airlock feeders.
A great number of pluggages occurred in the airlock feeders during a 2-
1/2 week period in March 1976, when the second stage shredder was out of ser-
vice due to a bearing failure and a single stage shredding was used. Down-
time for any particular conveying line and airlock feeder is approximately
1 hr to clear the plug.
Plant personnel feel that the new higher resistance wear back liner dis-
cussed in the preceding section is helping to reduce the number of plugs and
that the pluggage problem should improve as more elbow liners are replaced.
\l Gorman, P. G., L. J. Shannon, M. P. Schrag, and D. E. Fiscus. "St. Louis
Demonstration Final Report: Power Plant Equipment, Facilities, and En-
vironmental Evaluations," Prepared for U.S. Environmental Protection
Agency by Midwest Research Institute, Kansas City, Missouri, July 1977.
70
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As the original steel elbows wore, they became rough inside, and when a hole
was worn through, it was often patched. The rough inside surface and the
jagged edges of a patched hole tend to catch and hold RDF as it passes around
the elbow. The new liners being installed should remain smooth much longer
and should not cause as much catching of RDF and ultimate plugging of the
pneumatic conveying lines. However, time will tell if this theory is correct.
Since May 14, 1976, a record has been kept showing the location and exact
nature of each pluggage. Tabulation of these data are presented in Appendix
Table G-8.
Although conveying line pluggage is a serious problem requiring labor
man-hours to clear plugs, the time available for burning RDF has not been ad-
versely affected. While one line is being cleared, RDF conveying can be con-
tinued on the other lines.
Storage Bin
The bottom of the Atlas bin is 25 m (83 ft) in diameter. RDF is moved to
the four drag chain conveyors feeding the four pneumatic conveying systems by
a sweep conveyor operated by a large flexible member roller assembly installed
on the circumference of the Atlas bin. This roller assembly is in turn powered
by two variable speed motors located 180 degrees apart.
This flexible member roller assembly is supported on rollers moving in a
track installed on the circumference of the bin. By June 1976, this roller
assembly had stretched enough due to use so that its rollers came in contact
with some of the supporting structural steel members of the bin, causing ex-
cessive wear of the rollers and structural steel, and jamming of the assembly.
Two days of downtime were experienced due to this situation. The problem was
solved by having the bin manufacturer adjust and thighten the roller assembly.
The point of this discussion is that in future such installations, adjust-
ment of the Atlas bin sweep conveyor should be made early after start-up and
could require periodic adjustment thereafter.
In July 1976, a second period of downtime of 1 day occurred due to break-
age of the roller chain drive between the sweep conveyor roller assembly and
one of the variable speed motors.
Major Fire in the Processing Plant
On Saturday morning, November 6, 1976, at approximately 4 a.m., a fire
was discovered in the processing area of the plant. Firemen arrived within
minutes and had extinguished the fire by 6 a.m. The exact cause of the fire
is unknown, though spontaneous combustion is considered to be the likely cause.
The most serious damage was sustained by electrical wiring, necessitating a
2-week period to complete electrical repairs. Several electric motors,
71
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insulation on water pipes,and control room equipment were severely damaged.
The plant was not operational until November 22, 1976. During the 2 weeks,
employees cleaned and repaired much of the damage. All refuse received dur-
ing this period was diverted to the landfill. A further discussion of the
damage caused by the fire is contained in Appendix Table C-lf •
RAW REFUSE RECEIVED
Raw refuse is delivered to the processing plant by a variety of vehicles
including private cars, pickups, and trucks. The City of Ames does not pro-
vide citizens with municipally controlled refuse pickup service; hence, private
commercial operators of refuse pickup are the major delivery system. Figure
18 shown earlier in this section provides a schematic of the plant. Deliveries
of refuse are unloaded at the tipping floor. At this point, certain refuse
items are segregated such as large appliances, paper, and wood which is sub-
sequently sold. The balance of the refuse is processed. Deliveries in com-
mercial trucks are weighed prior to dumping and after unloading to obtain a
net load weight. This procedure is not practical for deliveries in cars and
a separate entrance and egress is provided for them. Private cars enter the
tipping floor through a gate, after depositing the $0.50 charge into the meter.
Private Car Deliveries
Since private car deliveries are not weighed, part of the study test pro-
gram involved weight sampling on several days to provide an estimate of refuse
quantities delivered from this source. The procedure used involved deposit of
the refuse in a special location on the tipping floor. From this point, the
plant front end loader scooped up the material and put it into a dump truck
which was then weighed. The number of truck loads weighed each day was totaled,
then divided by the number of private cars through the metered gate, yielding
a daily average weight per private car.
During the period between June 14 and August 30, 1976, private car de-
liveries were monitored on 51 days. These data are presented in Appendix
Table C-2, showing the average weight of 92.4 kg/private vehicle and the ex-
pected range of weights. The value of 92.4 kg/private vehicle has been used
to determine incoming quantities from this refuse source.
Statistical analysis shows that variability from day to day results in
an expected range of + 14.2 kg/vehicle which is 15% of the mean value of 92.4
kg/vehicle. However, since the total private refuse per day is less than 10%
of the total daily raw refuse delivered to the processing plant, a 15% range
in the average weight of raw refuse per private vehicle would not have less
than a 1.5% effect on the total plant material balance.
Statistical analysis of Table C-2 for any trends present revealed that
there was no correlation between kilogram per vehicle and day of the week.
72
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Therefore, no adjustment between kilogram per vehicle and day of the week
need be made, and the average value of 92.4 kg/vehicle can be applied uni-
formly, regardless of day. However, including all the data, there was an
80% statistical correlation between the number of private vehicles and day
of the week. This relationship is shown in Figure 23. The 4th of July week-
end data are not typical of the rest of the data. The 4th of July was Sunday
and Monday, July 5th was an official holiday. Deliveries on Saturday, July
3rd were unusually low for Saturday while deliveries on the Friday preceding
and the Tuesday following the holiday weekend were more typical of Saturday
deliveries. When July 2nd, 3rd and 6th data were discounted, the statisti-
cal correlation became 88% for a parabolic curve of the type Y = Ao + A^X +
A2X2.
The important conclusion is that the differences between days Monday
through Friday, the normal 5-day workweek, are small. However, as would be
expected, there is a sharp increase in the number of private vehicles on
Saturday, presumably because individuals have free time on Saturday to make
the trip to the refuse processing plant. Days immediately preceding or fol-
lowing holidays are special cases and do not necessarily correspond to what
could be normally expected for that day of the week.
Truck Deliveries
Truck delivery accounts for the majority of the total refuse received
at the processing plant by weight. It includes refuse that comes from a
variety of sources. Table 18 below provides a percentage breakdown of ref-
use sources during the months of June through November 1976.
TABLE 18. PERCENT OF RAW REFUSE WEIGHT BY SOURCE
Source (%)
Commercial licensed haulers 61
Nonscale refuse 17
City of Ames > 11
Private industry 6
Private commercial haulers 1
All others _4
Total 100
73
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too
X
D
Q
- 150
0)
Q_
V)
~O
_Q
£ 50
D -«"
Z
0
— Data for Period
June 14 through August 30, 1976
- (Correlation curve discounts July 2, 3, 6. 4th of *
_ July is Sunday,
_ holiday. )
—
—
July 6
K
_
•mMh
_ • •
- **S^^^
- * ^N*""""""""---»— *
• I — —
m^
m^m
1 1
Mon Tue
and Monday July 5 is official
88% Correlation Curve
• ^^>
-- . — !-^^"^
i :
i i
Wed Thu
•
.
0
July 2 /%
A /
/
/
\/
*S
^\ ^
\ July 3
1 1
Fri Sat
Day of the Week
Figure 23. Number of private vehicles delivering raw refuse to the refuse processing
plant versus day of the week.
-------
Summary of Refuse Received
A summary of the monthly incoming refuse is presented in Appendix Tables
A-l and A-2, and Figure 12. There is no recognizable significant pattern.
The reason for the low figure in November is because of the 2-week downtime
resulting from the fire that month.
An analysis of daily incoming refuse during June through October indi-
cates that Tuesdays and the last 4 days of each month tend to be the heaviest
receiving days. Wednesdays and Thursdays are days of the week which are the
lowest in Mg of refuse received, typically by about 10 to 15%. There do
not appear to be any other discernible patterns.
The volume of refuse received at the plant for the period January 1
through December 31, 1976, was 37,136 Mg. The design of the plant was
planned to accommodate nearly 94,000 Mg/year, operating on a one-shift 5
day workweek.
In 1976, 37,137 Mg of raw refuse was processed, and therefore, clearly,
the plant has the capability to process additional volumes of refuse. Con-
sideration is being given to alternatives that will increase refuse deliver-
ies and plant throughput, such as the establishment of agreements with addi-
tional communities to process their wastes.
PROCESSING PLANT LABOR
Fourteen people are required to administer and operate the refuse
processing plant as listed in the following manning table (Table 19).
Twelve of the 14 are direct labor, though not all are full-time employees.
Job Descriptions
Job descriptions for each work station in the processing plant are pre-
sented in Appendix Table C-3. Almost all full-time personnel are frequently
required to work at more than one station, as required, during a typical
operating day. Training for virtually all stations is conducted on-the-job.
The notable exception is specialized maintenance (electrical, hydraulic,
etc.), and operation of the plant control panel. Typically, only the chief
operator and the plant superintendent work at the control panel, since special
training and a thorough knowledge of the total system are required.
Analysis of Labor Allocation
The distribution of direct plant labor among 20 categories of work is
presented in Table 20 on a monthly basis for the period June 1 through
December 31, 1976. Totals for this period indicate that the bulk of the
75
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TABLE 19. MANNING TABLE FOR REFUSE PROCESSING PLANT
No. of Full- or
employees Title part-time Category
1 Public works director^/ Part Administration
1 Plant superintendent Full Direct supervision
1 Chief operator Full Direct labor
1 Front-end loader operator Full Direct labor
1 Truck driver Full Direct labor
2 Maintenance I Full Direct labor
1 Maintenance II and electrician Full Direct labor
1 Maintenance II Full Direct labor
4 Clean-up Part Direct labor
^ Secretary and tour guide Part Direct labor
14 (8 full-time - 6 part-time)
a/ 1570 of public works director's time assigned to refuse operations.
76
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TABLE 20. SUMMARY OF PROCESSING PLANT DIRECT LABOR HOURS
(Does not include plant superintendent)
Operat ion
Operating front-end loader
Tipping floor
Control room
Secretarial and tours
Shredders and hammers
General operations and
shredder grates
ADS
ADS drag conveyor
Screw feeder
Fe-metal magnets
Al-tnetal system
Conveyors
Wood chip system
Recovered metal
Rejects
Landfill
Maintenance
Cleaning process area
Janitorial
Miscellaneous
Total
June
Hr
261.5
215.25
203.5
97.5
46.0
424.25
30.0
74.25
19.5
4.0
32.5
41.5
11.5
48.5
73.0
35.0
42.0
341.25
84.0
31.0
2,116.0
%
12.4
10.2
9.6
4.6
2.2
20.2
1.4
3.5
0.9
0.2
1.5
2.0
0.5
2.3
3.4
1.7
2.0
16.1
4.0
1.5
100.0
July
Hr
247.0
224.75
91.0
83.5
90.0
433.75
6.0
95.5
0.0
0.0
82.5
8.0
15.75
24.5
46.25
52.75
104.5
326.75
60.25
44.25
2,037.0
August
X
12.1
11.0
4.4
4.1
4.4
21.3
0.3
4.7
0.0
0.0
4.1
0.4
0.8
1.2
2.3
2.6
5.1
16.0
3.0
2.2
100.0
Hr
241.0
207.25
216.5
64.0
126.0
454.0
6.0
122.5
0.0
65.5
25.0
6.0
12.0
34.5
64.25
37.5
5.0
259.0
74.0
35.5
2,055.5
'I.
11.7
10.1
10.5
3.1
6.1
22.2
0.3
6.0
0.0
3.2
1.2
0.3
0.6
1.7
3.1
1.8
0.2
12.6
3.6
1.7
100.0
September
Hr
216.0
147.0
179.0
70.0
60.0
473.0
0.0
0.0
0.0
0.0
0.0
0.0
9.0
14.0
75.0
19.0
128.0
414.0
79.0
53.0
1,936.0
"1,
11.2
7.6
9.2
3.6
3.1
24.4
0.0
0.0
0.0
0.0
0.0
0.0
0.5
0.7
3.9
1.0
6.6
21.4
4.1
2.7
100.0.
October
Hr
229.0
194.0
179.0
78.0
43.0
401.0
0.0
21.0
0.0
16.0
29.0
27.0
84.0
10.0
60.0
437.0
33.0
12.0
1,853.0
'/.
12.1
11.0
10.0
4.0
2.0
21.2
0.0
1.0
0.0
0.8
1.5
1.4
5.0
0.5
3.0
24.2
1.7
0.6
100.0
November
Hr
108.0
60.5
100.5
37.0
37.0
321.5
9.0
3.0
2.0
0.0
2.5
22.3
6.5
0.0
55.3
3.5
16.5
204.0
45.5
44.4
4,079.0
7.
10.0
5.6
9.3
3.4
3.4
27.8
0.8
0.3
0.2
0.0
0.3
2.1
0.6
0.0
5.1
0.3
1.5
18.9
4.2
4.2
100.0
Hr
242.0
211.0
221.0
94.0
132.0
401.0
111.0
29.0
0.0
32.0
44.0
40.0
13.0
0.0
79.0
25.0
58.0
203.0
57.0
41.0
2,033.0
7.
11.9
10.5
10.9
4.6
6.5
19.8
5.6
1.4
0.0
1.6
2.2
2.0
0.2
0.0
3.9
1.2
2.9
10.0
2.8
2.0
100.0
Total
Hr
1,544.5
1,259.7
1,190.5
524.0
534.0
2,908.5
162.0
324.3
42.5
101.5
202.5
117.8
96.7
148.5
476.8
182.7
414 0
2,185.0
432.8
261.2
13,109.5
%
11.8
9.6
9.1
4.0
4.1
22.2
1.2
2.5
0.3
0.8
1.5
0.9
0.7
1.1
3.6
1.4
3.2
16.7
3.3
2.0
100.0
-------
labor requirement is devoted to general operations and shredder grates (22.2%),
followed by cleaning of the process area (16.7), operation of the front-end
loader (11.8%), and tipping floor (9.6%), and the control room operation
(9.1%). These categories account for nearly 70% of the total work performed
at the plant. Prior to September, maintenance was unscheduled, i.e., con-
ducted only after breakdown. Beginning in September, a program of regularly
scheduled preventative maintenance was begun. This included scheduled lubri-
cation, adjustment when necessary of mechanical drives, conveyor belt ten-
sion, etc., and most importantly careful inspection of equipment for loose or
worn parts which are then tightened or replaced as necessary.
Data are presented in Figure 24 comparing overtime, regular and total
hours of work at the plant. While regular working hours have remained rela-
tively stable over the period, overtime has diminished, indicating improved
management and increased working efficiencies.
During the period June 1 through December 31, 1976, the labor hours of
input per Mg of refuse processed at the plant averaged 0.61 hr/Mg. For each
month, the figures were: June - 0.63; July - 0.64j August - 0.62; September -
0.61; October - 0.54; November - 0.62; and December - 0.65.
Labor Turnover and Working Conditions
Labor turnover experience at the processing plant has been extremely low
for full-time employees, with the exception of the Maintenance I position. A
considerable degree of employment loyalty exists among full-time employees,
undoubtedly because of the uniqueness of the processing plant and the atten-
tion it has received within the community. Full-time employees appear to be
satisfied with the work and demonstrate a high degree of willingness to share
work responsibilities, particularly in the area of maintenance.
Part-time employee turnover has been high, with the exception of the
position of the secretarial and tour guide position. The janitorial position
has changed on the average of two to three times per year. Reasons given for
the high turnover among part-time employees are two-fold: (a) most part-time
employees consider the job as only temporary and leave when better positions
are found or when no longer needed at the plant, and (b) most of the part-
time employees have been students at the university, who leave due to gradua-
tion or changes in class schedules.
Working conditions at the processing plant vary. Personnel who work in
the control room are afforded the conveniences and comforts of inside work.
The remainder of the plant can be divided into two working areas and working
conditions are discussed in each as follows:
78
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2500
2000
-o
-------
Tipping Floor--
The most serious factor is exposure to cold weather in the winter. Large
doorways permit windchill as well as low temperatures. To quote an operator,
"When it's 20 below outside, it's 22 below on the floor." This has been cited
as a reason for turnover in one of the Maintenance Man I positions. During
the summer the air is occasionally somewhat dusty, but the plant personnel do
not feel this is a serious problem. Noise levels are occasionally high; noise
surveys are planned for 1977. Ultraviolet light fly traps are used to control
flies during the summer.
Processing Plant—
The conditions inside the processing plant contains several significant
features. These include: dust, noise, and occasional flying debris. Precau-
tions include the use of hard hats, dust filter masks, safety glasses, gloves,
and specified monitoring locations on steel grates. All grates and ladders
have safety railings.
One important provision is assuring the safety of operating personnel in
the processing plant is readily accessible and reliable communication with
the chief operator. Telephones are located at many stations in the process-
ing plant, including all monitoring areas. In addition, there is a P.A. sys-
tem which is clearly audible over the noise created by process machinery.
Operators monitoring the process are never out of immediately available con-
tact with the chief operator. They can give or receive a message at any
time. Battery-powered, portable radios are also kept for this purpose.
In accordance with OSHA requirements, a siren has been provided which
sounds when each major item (primary or secondary shredder, etc.) or set of
items (group of conveyors) is started up. In starting up the process, the
siren sounds 10 times altogether. The siren is coupled to start-up controls
on the console and sounds automatically as equipment is started.
PROCESSING AND DOWNTIME
This part of the report provides information about plant operating hours
and the amount of downtime incurred. The first section will discuss process-
ing, the second downtime, and finally, a comparison of the two.
Plant Processing
During the months of June through December 1976, records have been main-
tained on plant operations. Detailed data are presented in Appendix G. The
raw refuse in-feed conveyor (Conveyor C-l) run-time is recorded giving the
actual time raw refuse was being shredded each day. The feeder for the pneu-
matic conveying system, which carries the refuse derived fuel (RDF) from the
processing plant to a storage bin is also recorded. The processing plant
80
-------
cannot operate unless the pneumatic conveying system is in operation. There-
fore, this last meter records the total time the plant was in operation.
From June 1 through December 31, 1976, total plant operating time was
946.5 hr or 7.01 hr/day. Total operating time for the raw refuse in-feed
conveyor (actual processing time) was 736.1 hr, or 5.45 hr/day. A use fac-
tor can consequently be calculated by dividing in-feed hours by total operat-
ing hours. For the entire period, the use factor was 77.8%.
The in-feed conveyor daily hours are less than the plant operating hours
due to downtime on the various items of equipment. During normal processing,
the in-feed conveyor is stopped when downtime occurs. The balance of the
plant is left in operation except for the particular component of machinery
causing the downtime, which may, or may not, be shut down depending on the
nature of the problem.
The use factor will never be 100% even without any downtime because the
pneumatic conveying system must be started first before any of the plant con-
veyors can be operated. Also, when the plant is shut down at the end of each
day, a timer allows the pneumatic conveying system to continue operating for
a few minutes to clear the pneumatic conveying pipeline.
Downtime
Records have been maintained at the plant on the number of hours the plant
was not operating because of subsystem malfunctions. This information in-
cludes a breakdown of downtime by subystemsj e.g., shredders, ferrous metal
separation, nonferrous metal separation, the air density separation (ADS) sys-
tem, the associated conveyors of each, and the tipping floor.
Table 21 presents the total monthly downtime for the period from June 1
through December 31, 1976, and the percent of this total attributable to each
of the five subsystems. Downtime is defined as the time the total system can-
not be operated because a subsystem is malfunctioning, considering as well,
the amount of refuse delivered to the plant for 1 day. For example, if only
50 Mg are delivered to the plant, downtime is only the amount of time needed
to process 50 Mg, not the full 8 hr. Further, necessary maintenance is not
considered downtime; e.g., hammer changes, and the time required to change
the trailer which collects recovered metals. Also, if a subsystem is inopera-
tive, but does not affect the operation of the rest of the system, the time
is not considered downtime.
From Table 21, it is clear that the ADS subsystem is the largest contri-
butor of downtime, accounting for nearly 58% of the total. Most of the prob-
lems with the ADS subsystem are caused by the ADS drag conveyor. The second
major contributor is the shredder subsystem which accounts for 30% of the
total.
81
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TABLE 21. MONTHLY SUMMARY OF PLANT DOWNTIME BY SUBSYSTEM
oo
to
Shredder
Month
June 1976
July
August
September
October
November—'
December
Total-^
a/ Does not
November
Hours
7.26
14.07
15.55
9.04
2.96
5.80
7.62
62.30
include
85.80
Percent
19.4
41.8
49.3
34.0
13.1
34.6
20.0
30.1
downtime
20.6
ADS
Hours
28.58
15.40
10.05
13.09
17.54
7.51
26.82
118.99
Percent
76.4
45.8
31.9
49.2
77.3
44.8
70.3
57.5
attributable to
87.51 21.0
Ferrous
Hours
0.50
1.94
3.93
1.48
2.18
3.46
2.05
15.54
the fire.
83.46
Percent
1.3
5.8
12.5
5.6
9.6
20.6
5.4
7.5
Downtime
20.0
Non ferrous
Hours
0.25
0
0
0
0
0
0
0.25
caused
80_.00
Percent
0.7
0
0
0
0
0
0
0.1
by the fire
19.2
Tipping floor Totals
Hours Percent Hours
0.83 2.
2.23 6.
2.01 6.
3.00 11.
0 0
0 0
1.68 4.
9.75 4.
is presented
80.00 19
2 37.42
6 33.64
3 31.54
2 26.61
22.68
16.77
4 38.17
7 206.83
below.
.2 416.77
Percent
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Total
142.30
23.4 198.99
32.8 95.54 15.7
80.25
13.2 89.75
14.8 606.83
100.0
-------
For descriptive purposes, downtime caused by the fire at the processing
plant in November is presented as a footnote to the table. This incident is
considered extraordinary, however, and should be used accordingly.
Summary of Plant Processing and Downtime
During the period of the study (June through December 1976), the plant
was manned and operational 946.5 hr. Actual processing time was 736.1 hr,
or 77.8% of the time. The amount of refuse processed during the period was
21,360 Mg. As shown in Table 22, the average Mg of refuse processed was 22.6/
available hour of time, and 29.0/hr of actual processing time.
Also during the period of the study, records indicate that the plant was
down 21.9% of the time, in accordance with the definition of downtime pre-
sented above and relative to the total hours the plant was manned and opera-
tional. Not included in Table 22 is the number of hours when the plant was
not operational because of the fire between November 6 and 21. The inclu-
sion of these hours, which raises the total to 606.83 hr of downtime, results
in a downtime factor of 39.1%.
ELECTRIC POWER UTILIZATION
Electric power consumption has been recorded for the total plant and
seven individual major items of equipment for the period June 1 through
December 31, 1976» These data are summarized by month in Table 23. Weekly
electricity consumption figures are included herewith as Appendix Table C-5.
For purposes of comparison, consumption of electricity is presented by major
equipment piece and indirect plant (i.e., lighting, ventilation, heat, etc.)
both in terms of kilowatt hours of use and relative percentages. A listing
of the major electric motors installed in the plant is presented in Appendix
Table C-6.
As expected, the shredders and storage bin were the major electricity
consumers, accounting for 26.3 and 18.6%, respectively. The single largest
consumption category, however, was indirect. This item increased signifi-
cantly during the months of November and December primarily because of the
use of electric resistance heating and the decision to maintain lighiting
in the plant 24 hr/day to allow visual plant inspection of night watchmen
checking for possible fire.
The Shredders
The second stage shredder uses almost twice as much power as the first
stage shredder. The weight of refuse shredded per day is less in the second
stage shredder by the amount of ferrous metal removed by the magnetic belt
between the first and second stage shredders. Both shredders are operated
by 746 kw (1,000 hp) motors. Therefore, the question is raised: Can the
83
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oo
TABLE 22. PLANT OPERATING HR DOWNTIME AND REFUSE PROCESSED/OPERATING HR
(June 1 through December 31, 1976)
Mon th
June
July
August
September
October
November
December
To tall/
Average
Total plant
operating
hr
125.2
133.6
157.4
148.2
142.0
77.0
163.1
946.5
Downtime
hr
37.42
33.64
31.54
26.61
22.68
16.77
38.17
206.83
7,, of downtime to
plant operating hr
29.9
25.2
20.0
18.0
16.0
21.8
23.4
21.9
Actual
processing
hr
98.1
99.1
121.5
120.6
112.2
54.1
130.5
736.1
Refuse
processed
(Mg)
3,354
3,194
3,314
3,198
3,420
1,739
3,141
21,360
Process
Mg/operating hr
26.8
23.9
21.1
21.6
24.1
22.6
19.3
22.6
Rate
Mg/processing hr
34.2
32.2
27.3
26.5
30.5
32.1
24.1
29.0
a/ Excludes the downtime due to the fire in November.
-------
TABLE 23. WEEKLY ELECTRIC POWER CONSUMPTION FOR REFUSE PROCESSING PLANT AND STORAGE BIN
M. 'nth
June
kw-hr
•/.
July
kw-hr
%
August
kw-hr
%
September
kw-hr
00 X
Ul
October
kw-hr
%
Novcmbe r
kw-hr
^
December
kw-hr
7.
Totat
kw-hr
%
First stage
shredder
19,594
10.3
23,567
10.7
21,486
10.4
21,840
9.8
21,420
10.8
16,520
9.4
25,620
8.5
150,047
9.9
Second stage
shredder
36,371
19.4
42,509
19.3
40,314
19.5
48,137
21.6
30,660
15.4
15,400
8.8
36,680
12.1
250,371
16.5
ADS fan
14,003
7.4
14,096
6.4
15,277
7.4
15,377
6.9
12,810
6.5
8,190
4.7
16,870
5.6
96,623
6.4
Pneumatic
conveying blower
(to Atlas bin)
12,184
6.4
11,894
5.4
12,381
6.0
12,703
5.7
11,060
5.6
6,720
3.8
12,810
4.2
79,752
5.3
Processing plant
indirect^/
65,953
34.8
86,340
39.2
77,560
37.5
82,010
36.8
79,715
40.1
102,520
58.5
163,325
53.9
657,423
43.3
Storage bin
(storage and pneumatic
conveying to boiler)
41,125
21.7
41,849
19.0
39,902
19.3
72,788
19.2
42,960
21.6
26,000
14.8
47,760
15.8
282,384
18.6
Total processing plant
and storage bin
189,530
100.0
220,255
100.0
206,920
100.0
222,855
100.0
198,625
100.0
175,350
100.0
303,065
100.0
1,516,600
100.0
% by month
12.5
14.5
13.6
14.7
13.1
11.6
20.0
100.0
Includes heat, light, ventilation, maintenance (e.g., welding, tools), conveyors, feeders and metals recovery.
-------
work load be more uniformly distributed between the two shredders by install-
ing smaller grate sizes in the first stage shredder? Smaller grate sizes in
the first stage shredder will increase its power consumption. What is not
known is the exact relationship of particle size to power usage for the sec-
ond stage shredder. It would be undesirable to increase total kilowatt-hours
for both shredders (Shredder No. 1 plus Shredder No. 2). However, if an elec-
tric power use increase for the first stage shredder due to smaller grate size
were followed by a corresponding decrease in the second stage electric power
consumption, then this would be a desirable operating condition from a power
standpoint.
Another question is what would be the effect on hammer wear. The pre-
ceding section on shredder maintenance shows that the first stage hammer
working life is slightly less than twice the working life of the second stage
shredder hammers. Also, it requires more man-hours per Mg of refuse processed
to change and balance hammers in the second stage shredder than in the first
stage shredder. Therefore, a decrease in the first stage hammer life, if it
resulted in a corresponding increase in the second stage shredder hammer life,
would be beneficial to the shredder system operations.
Electric Power Consumption
The data provided in Table 24 are presented to establish a basis for com-
parison with other processing plants. Power consumption averaged 2,060 kw-hr/
actual processing hour. This figure drops to 1,602 kw-hr of consumption/hour
the plant was manned and operational. Electric power consumption per Mg of
refuse processed during the period averaged 71.0 kw-hr.
REFUSE DERIVED FUEL (RDF) CONVEYING SYSTEM AND STORAGE BIN
This part of the total operation is, at least in part, unique to the
Ames facility because of the nearby proximity of the processing plant to the
electric power generating plant. RDF transport is by pneumatic conveying
from the processing plant to the storage facility and also from the storage
facility to the electric power plant boilers.
Table 25 presents a monthly summary of the operation of the RDF pneuma-
tic conveying system, drawn from daily figures included in Appendix Table C-
7. The period covered is from June 2 through December 31, 1976.
The use factor derived at the bottom of the table provides an indication
of the reliability of the conveying system and storage bin or 84.2% of the
total available operating hours during the period not including the November
fire downtime. The resulting downtime for the system may be caused by mal-
function of the pneumatic line system or the equipment in the storage bin.
Daily records of the causes of downtime and maintenance for the pneumatic sys-
tem and the storage bin are presented in Appendix Tables C-8 and C-9. A sum-
mary of this information is presented on a monthly basis in Table 26.
86
-------
TABLE 24. ELECTRIC CONSUMPTION RATIOS (June 1 through December 31, 1976)
(in icv-hr)
Month
Electric consumption/
operational hr
Average
1,602
Electric consumption/
processing hr
2,060
Electric consumption/
Mg of refuse
June
July
August
September
October
November
December
1,514
1,649
1,315
1,504
1,399
2,277
1,858
1,932
2,223
1,703
1,848
1,770
3,241
2,322
56.5
69.0
62.4
69.7
58.1
100. &i'
96.5
71.0
a/ Includes electric power used in maintenance activities associated with fire
damage repairs.
Note: Increases in November and December are partially attributable to addi-
tional space heating requirements. The plant is heated with electric
resistance heat.
TABLE 25. RDF CONVEYING SYSTEM-OPERATING HR AND COMBUSTION
RATE MONTHLY SUMMARY
Pneumatic conveying line
hr of oceration
Month
June
July
August
September
October
November
December
Total
Use factor
tf/
A
537.5
567.9
578.2
575.7
625.9
300.8
600.0
3,786.0
79.3
B
9.1
0.2
3.2
0.0
0.0
0.0
0.0
12.5
0.3
c
0.4
0.3
3.9
0.0
0.0
0.0
0.0
4.6
0.1
D
513.0
566.2
507.9
632.1
619.3
308.2
609.2
3,755.9
78.6
Hr RDF
burned^/
568.9
623.5
600.1
643.9
634.8
312.6
636.3
4,021.1
84.2
RDF
burned
(Mg)
2,079.1
2,445.5
2,597.7
2,464.4
2,684.0
1,396.4
2,289.6
15,956.7
Average
burned rate
(Mg/hr)
3.7
3.9
4.3
3.8
4.2
4.5
3_.6
4.ok/
aj Maximum hour total system was in operation on daily basis.
W Total Mg/total hour. Not arithmetic average of column.
£/ Percent of available hour. Available hour = 199 days (24 hr/day = 4,776)
excluding 14 days downtime resulting from fire in November.
87
-------
oo
oo
TABLE 26. SUMMARY OF DOWNTIME FOR PNEUMATING CONVEYING LINES AND STORAGE BIN
(June 1 through December 1976)
Pneumatic conveying system downtime
Month
June
July
August
September
October
November-
December
Total
Line A
59.8
73.3
39.7
68.6
21.6
14.1
62.3
339.4
Line D
69.7
58.2
105.6
21.4
24.1
8.6
53.3
340.9
Hr when both
lines down
simultaneously^/
20.6
21.4
7.2
7.9
0.7
0.3
19.3
77.4
Storage bin
% of available
operating hrk'
3.3
2.9
1.0
1.1
0.1
0.1
2.6
1.6
Hr
55.4
21.8
75.5
1.3
15.9
0.0
4.4
174.3
% of available
operating hr_'
8.0
2.9
10.1
0.2
2.1
0.0
0.6
3.6
Grand total
of downtime
76.0
43.2
82.7
9.2
16.6
0.3
23.7
251.7
7. of
available
operating hr
10.9
5.8
11.1
1.3
2.2
0.1
3.2
5.30
a/ Since four lines are available for use, the pneumatic system can remain operational unless all lines
are not functional. Hence, the pneumatic subsystem downtime is counted only when all lines are not
operational.
b/ Days per month refuse could have been burned x 24 hr.
£/ Reduced hours resulting from November 6 fire in processing plant.
-------
Of the problems encountered with the pneumatic conveying system, the
most prevalent cause of downtime is stoppage of the feeder with pieces of
wire, rubber and wood, accounting for slightly more than 50% of the failures.
Plugged lines are another source of problems, as are repairs to elbows in the
line. Downtime of the storage bin is not very prevalent, although the bin
was down several days in June. The most usual occurrence is problems with
the sweep drive. For both subsystems, the amount of downtime has shown evi-
dence of decreasing during the year.
The hours of labor required to repair and maintain the pneumatic convey-
ing system for the June through December period totaled 1,184.3 hr, 430.8
of which were paid on an overtime basis. Similarly, hours of labor for re-
pairing and maintaining the storage bin totaled 544.5, 92 of which were paid
at overtime rates.
OTHER PLANT EVALUATIONS
This part of the report presents four items which individually are not
lengthy enough to warrant a section unto themselves, but are considered per-
tinent to the study. Specifically, shredder maintenance, refuse throughput,
plant water consumption, and net electric power generation are discussed.
Shredder Maintenance
During the course of the study, the hammers on Shredder No. 1 were re-
placed once, and three times on Shredder No. 2. Each shredder has 48 hammers,
whose dimensions are shown in Figure 25. Cost and working life experience
to date for these hammers are as follows:
First stage
shredder
Second stage
shredder
Number of hammers
Weight of each hammer (kg)
New cost of each hammer ($)
Cost ($/kg)
Number of working faces/hammer
Useful life
Mg each face
Total (Mg)
48
69
146
2.12
2
10,000
20,000
48
24
49
2.04
4
3,000
12,000
89
-------
FIRST STAGE SHREDDER HAMMERS
101.6
(4)
190.5
(7.5)
60.3
(2.375)"
95.3
(3.75)
476.3
(18.75)
(5)
Front View
I
Side View
Dia. 88.9
(3.5)
SECOND STAGE SHREDDER HAMMERS
~*"
•
*~
1
10
/ ,
('
44.5
(1.75) I -*•
i
IV
*;
495
(19
1
' T~
12.7
(0.5)
.3 ,
.5)
F
Front View
-J
/
V
(
55.6
(2.188)
1
p'"— >
^~-S
S-***
X
^_x
^-J
1
T
1
k
\
/
f
f
19.1
(0.75)
174.6
(6.875)
Dia. 76.2
"*^ r*~(3.688)
Side View
Note: All Dimensions in mm and (Inches)
Figure 25. Dimensions of shredder hammers,
90
-------
Time required to change and
balance hammers
Date Plant time Labor
changed (hr) (man-hr)
First stage shredder 8/7 and 9/11 22.4 89.5
Second stage shredder 7/30 12.4 49.5
9/14 4.1 16.5
12/8 3.0 12.0
As the above information shows, plant maintenance personnel have become
considerably more proficient in changing the shredder hammers. When the
first stage hammers were changed for the first time, the excessive labor
hours required to perform the task were partially attributable to difficulties
in removing the hammer shaft from the shredder. Maintenance personnel be-
lieve that the hammers were used too long, causing the shaft to warp.
In July 1976, the curtains in both shredders were replaced with new rub-
ber curtains. Following are the material costs and labor hours to do this
work.
First stage Second stage
shredder shredder
Material Number Total ($) Number Total ($)
Curtains 3 780 2 600
Hangers 3 54 2 36
Hanger rod 1 6 1 6
Total 840 642
Total Total
Number of men man-hours Number of mean man-hours
Labor 6 16.5 3 16.5
The total for both shredders was $1,482 and 33 man-hours labor.
Summary of Plant Mass Balance
The purpose of this section is to present some idea about processing
plant input and output, that is, an estimated mass balance for refuse. Un-
fortunately, the system is not equipped with a scale to weigh the actual
amount of RDF after processing. However, a means was provided to allow
91
-------
periodic sampling on a mass-density basis. The problem with such a measure is
that the mass-density of RDF undoubtedly varies significantly, if visual ob-
servation is reliable. Nevertheless, the data presented in Table 27 provide
a rough approximation of refuse mass measurement error. The average for the
period June 1 through December 31, 1976, is about 11%. Some of this loss may
be a problem of inaccurate measurement rather than material loss. For ex-
ample, incoming refuse delivered by private automobiles is an average figure
based on sampling (see Appendix Table G-2) and can vary significantly. In
addition, commercial vehicles tare is a one-time measurement and vary because
of fuel carry. This compares with a loss factor at the St. Louis pilot plant
of 6%. The refuse processing plant at Madison, Wisconsin, experienced a loss
factor of 2 to 5%.
Another possible reason for the apparent discrepancy is that monthly
"inventory" carryover figures are unavailable. The period under study is
not sufficiently long for this difference, if any, to average out.
Net Electrical Power Generation
Table 28 presents information relevant to determining the net energy ef-
ficiency of the refuse processing plant. During the period June 1 through
December 31, 1976, the refuse processing plant consumed slightly more than
1.5 million kw-hr, of electricity. The generation of electric power directly
attributable to RDF for the period was 11.97 million kw-hr, yielding net
power generated of 10.45 million kw-hr. For the period, this amounts to an
average electricity content per Mg of refuse received of 489.1 kw-hr of power.
If the electric power content is calculated on the actual amount of RDF fed
into the boilers (15,957 Mg), the power content increases to 654.6 kw-hr/Mg.
92
-------
VO
CO
TABLE 27. SUMMARY OF PLANT MASS BALANCE
(June 1 through December
31, 1976)
Month
June
July
August
September
October
November
December
Total
Refuse
received
(Mg)
3,354
3,194
3,314
3,198
3,420
1,739
3,141
21,360
Recovered
materials
(Mg)
547
537
478
471
600
268
498
3,399
Refuse derived
fuels by difference
(Mg)
2,807
2,657
2,836
2,727
2,820
1,471
2,643
17,961
Refuse derived
fuel by measure
(Mg)*/
2,079
2,446
2,598
2,464
2,684
1,396
2,290
15,957
Apparent
error/loss^/
Mg %
728 26
211 8
238 8
263 10
136 5
75 5
353 13
2,004 11
a/ Density sampling at storage bin.
b/ Difference between RDF by difference (theoretical) and measured RDF.
changes in monthly carryover or moisture and other losses.
Does not consider
-------
vo
.£-
TABLE 28. NET ELECTRICAL POWER GENERATION (June 1 through
December 31, 1976) (in kw-hr)
Month
June
July
August
September
October
November—'
December
Total
Processing plant
electric power
consumption
189,530
220,255
206,920
222,855
198,625
175,350
303,065
1,516,600
Electric power
generation
attributable to RDF^/
1,680,224
1,849,345
1,765,991
2,001,168
2,057,143
985,485
1,633,061
11,972,417
Net electric
power generated
1,490,694
1,629,090
1,559,071
1,778,313
1,858,518
810,135
1,329,996
10,445,817
Net electric power
generated/mg of
raw refuse received0.
444.5
510.1
470.5
556.2
543.4
465.9
432.4
489.1
a./ Based on plant records of monthly amounts of RFD and coal used.
b/ Excludes 2-week period of downtime after fire November 6.
c/ Based on amounts of raw refuse received at processing plant, not Mg of RDF burned.
-------
SECTION 7
ECONOMIC EVALUATION
The economic and financial aspects of the refuse processing plant at
Ames are presented in this section of the report. Major areas of analysis
include total plant investment and operating revenues and expenses. Most
of the analyses cover the entire year of 1976. Operations prior to that time
have been considered as start-up expense. Detailed expense analyses on each
subsystem in the plant cover only the period from June 1 through December 31,
1976, since this is the term of the study.
The total capital investment in the Ames facility was $6.3 million, as
defined for this study. First-year operating expenses were $1.15 million;
revenues were $448,000. Based upon the amount of raw refuse received at the
plant, the net cost per megagram of refuse received was $18.90.
Consideration of operating expenses and revenues should include the fact
that this was the first full year of operating the plant. Though detailed in-
formation is not available to determine total effects of the learning curve,
discussions with administrative personnel indicate that the experience gained
to date will be advantageous in the future. Also, individual monthly expense
data should be viewed as approximate. The City of Ames uses a cash account-
ing method, i.e., expenses are not recognized until paid. This accounts for
unusually large expenses in some months, and correspondingly low expenses in
other months. Standard accounting practice suggests use of the accrual method
of accounting, i.e., recognizing expenses at the time they are incurred. In
spite of this minor shortcoming, the totals for the year are valid.
The total expenses figures presented herein differ from those published
by the City of Ames. The difference lies primarily in the method of account-
ing for interest, principal payments on the municipal bond issue used to fi-
nance the project, and depreciation. The City of Ames does not consider
depreciation; rather, they are expensing the principal payments on the bonds.
Also, they are expensing the full amount of interest paid on the debt. For
this analysis, estimates of equipment useful life are considered and a depreci-
ation schedule used to amortize the capital cost over the useful life. Also,
the total interest on the indebtedness over the full 20 years has been an-
nualized, i.e., evenly distributed.
95
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CAPITAL INVESTMENT
The total initial investment in the solid waste processing project
reached a level of $6,3 million as summarized in Table 29. A more detailed
identification of individual cost elements is provided in Appendix Table D.
Not included in the figures of Table 29 are: the cost of the plant feasibil-
ity study, working capital to operate the plant, nor initial inventory of
supplies and replacement parts. Estimates on the last item could not be ex-
tracted from the accounting data. The city has used its general operating
fund as a working capital source. The cost of the original feasibility study
was about $20,000. The acquisition of a supplies and replacement parts in-
ventory apparently was expensed within the first few months of operation,
though the accounting records do not clearly reveal this. Hence, some of the
inventory may be included in the "start-up expense" figure. Some basic as-
sumptions used in developing the investment classifications are discussed
below:
TABLE 29. SUMMARY OF CAPITAL INVESTMENT FOR THE AMES
SOLID WASTE RECOVERY PLANT AND SYSTEMS
Investment category Investment cost
Land for plant site $ 82,841
Improvements on plant site (sewers, etc.) 10,227
Land for landfill 15,000
Processing plant and equipment 4,084,207
Auxiliary equipment, tools and parts inventory 164,827
RDF storage, firing equipment, and boiler modifications 1,599,127
Start-up expense 321,578
Total invested capital $6,277,807
Land
This category includes the actual plant site at acquisition cost (pur-
chased a few years prior to project commitment), 10 acres of landfill, and
plant site improvements (street, sewer, etc.). The inclusion of improvements
as part of land investment is made in accordance with generally accepted ac-
counting principles.
96
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Start-Up Expenses
Included within this category are all operating expenses, training, and
interest expense incurred from start date through December 31, 1975, a period
of about 4 months.
A 4-month start-up period may be considered longer than usual for some
industries, but is not unreasonable, considering the unique character of the
refuse processing plaut. At the time the Ames plant went into operation in
the fall of 1975, the St. Louis demonstration plant had ceased operations
and no other refuse processing plants were in commercial operation. The Ames
plant was applying a new technology, resulting in a 4-month start-up period.
Future new plants, relying on a body of knowledge gained from existing plants
such as Ames, may very well have shorter start-up periods.
Plant and Equipment
This classification is divided into three subclasses, i.e., the actual
processing plant and operable equipment housed therein; the investment in
auxiliary equipment, such as the front-end loader, tools, and spare parts;
and the processed refuse storage bin, pneumatic conveyance, firing equipment,
and power plant boiler modifications. This subclassification provides a logi-
cal systems breakdown according to use.
Depreciation and Amortization
The purpose of establishing such schedules recognizes the need to allo-
cate investment costs over the estimated useful life of the equipment, or in
the case of start-up expense, over a reasonable period of expected benefit
accruing therefrom. Such allocations are not typically done for a public
project, since no taxation benefits are involved. In reality, however,
depreciable assets do have a finite life and investment cost should be allo-
cated over the period of usefulness. Internal Revenue Service general guide-
lines have been used because no prior experience guidelines are available.
Total annual depreciation is calculated to be $353,878, or $29,489 per month,
using straight line methods.
Engineering Design
Expenses are shown separately where applicable in the detail schedules
for each investment category. All other cost items have been detailed to
the extent data were available.
The Ames system design was based upon the perceived needs of the com-
munity. However, in larger cities with higher daily volumes of refuse re-
quiring larger refuse processing plants, certain economies of scale could
97
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possibly be achieved. For example, at Ames the installation of 50 Mg/hr
shredders to process only 200 Mg/day of refuse at first seems expensive. How-
ever, municipal solid waste contains a sufficient amount of large bulky items
which cause excessive maintenance and process downtime for shredders smaller
than 50 Mg/hr. Therefore, the shredders at Ames are the smallest practical
size that could be used, even though their capacity is not fully utilized.
A comparison of actual with estimated investment costs is presented in
Table 30. Consideration should be given to the difficulty in developing
cost estimates for a project of this size.
TABLE 30. COMPARISON OF PLANNED AND ACTUAL COSTS
Capital investment Estimated Actual
Processing plant
Pneumatic conveyors
Storage bins
Electric work
Boiler modification
Land
Engineering
Subtotal
Minor equipment and start-up
$3,898,000
150,000
687,000
114,000
179,000
156,000
275,000
5,459,000
100,000
$4,116,526
164,388
551,292
314,020
178,988
108,068
376,896
5,810,178
486,405
To tar investment $5,559,000 $6,296,583
The most significant cost element difference is for minor equipment and
start-up expense. For purposes of accountability, all operating expenses
accrued from August 30, 1975 to January 1, 1976, were arbitrarily considered
start-up expenses. The decision to do so is based on year-end accounting
convenience and the time necessary to learn to operate the plant and achieve
a regular operating schedule after that time period. The total project esti-
mate was exceeded by $737,583 or 13.3% which is a relatively low increase con-
sidering the newness of refuse processing technology. However, as shown in
Table 30, much of this increase is start-up expense which could not accurately
be predicted before the plant was constructed. When the minor equipment and
start-up is removed, the difference between estimated and start-up is
$351,178 or 6.4%. Of this amount, $200,020 is extra electrical work. The
electrical portion of the project was expanded beyond the original estimate
due to lack of appropriate electrical information from equipment suppliers,
and addition of some electrical circuits. If the increased electrical work
98
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is removed, the increase in actual versus estimated project cost is only
$151,158 or 2.8%.
A "rule of thumb" in many construction projects is that a 10% cost over-
run is "normal" or acceptable increase. The estimated project cost was estab-
lished during 1971 through 1973. Due to an unforeseen strike in the construc-
tion industry, the plant start-up date was delayed approximately 6 months and
full production did not begin until January 1976. This time delay contributed
to increased costs. In summary, considering the time span between when the
estimate was made and when full production was achieved at the processing
plant, the estimate of plant investment costs is as accurate an estimate as
could have been expected.
ECONOMIC OPERATING EXPERIENCE
This section of the report presents the financial operating results of
the Ames solid waste processing plant. Though the study did not begin until
June 1, 1976, an effort has been made to provide results for the entire cal-
endar year. First consideration is given to revenues, including income
derived from the cash sale of recovered resources, dump fees, and noncash in-
come obtained from the combustion of processed refuse used to generate elec-
tric power at the municipally owned electric generating plant. The second
part of this section is devoted to an analysis of operating expenses.
In most instances, the term ". . . per Megagram of Refuse Received" is
used as the basic common denominator of presenting comparative data. Speci-
fically, this term refers to the amount of refuse delivered to the plant,
prior to processing. The reason for selecting this term as a standard of mea-
sure is that it is the most accurately recorded measure of refuse volume and
also it can be used for comparison with data from other plants irrespective
of plant configuration, operating efficiencies, etc.
Cash Revenues
Cash revenue sources include the following:
1. Dump fees collected at the refuse processing plant from private
citizens, commercial firms, and contract refuse haulers.
2. Sales of recovered resources extracted from the solid waste stream
including metals, wood chips, and paper.
Table 31 provides a monthly breakdown of revenues for 1976. For the year,
cash sales of recovered metals account for 78% of the total, followed by dump
fees at 19%, wood chips at 2%, and paper at 1%. Monthly totals indicate vir-
tually no pattern, though the summer months are moderately higher. However,
99
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TABLE 31. PROCESSING PLANT REVENUE
Cash revenues
Month
January
February
March
April
May
June
July
August
September
October
November
December
Metals
$ 5,269
7,357
8,013
6,104
10,941
9,075
11,499
9,932
8,683
9,937
9,447
4,258
Dump
fees
$ 1,216
987
2,437
1,893
1,790
2,663
1,780
2,133
3,049
2,930
1,709
1,494
Wood
chips
$ 38
264
146
241
258
322
135
249
161
120
79
229
Paper
__
$ 469
371
296
399
341
-
_
mm tmrnm
-
_
•• «M
Total
$ 6,523
9,077
10,969
8,534
13,388
12,401
13,414
12,313
11,892
12,987
11,789
5,981
Noncash
Revenue
for
Refuse
received
(Mg)
2,895
2,719
2,786
3,900
3,476
3,354
3,194
3,314
3,198
3,420
1,739
3.141
revenues
credit
RDF
Dollar
value
$ 29,321
19,215
25,974
38,874
23,766
22,170
24,124
22,674
34,983
39,527
14,735
24,090
Total $100,515 $24,081 $2,242 $1,876 $129,268 37,136 $319,453
100
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part of the increase may be attributanle to increased public awareness and
use of the waste processing plant.
Most of the recovered metal sales (75%) is derived from the sale of
scrap ferrous metal extracted by the ferrous metal separation subsystem. The
remaining 25% of metal sales include the sale of "white goods," i.e., refrig-
erators and other discarded appliances, separated from the waste stream prior
to processing. Operating history indicates that scrap metal accounts for
about 7% of the total waste stream, while white goods represent only about
0.75%. During the year, white goods brought about $9.07/Mg. Scrap ferrous
metal is sold on a contract basis to a firm in Gary, Indiana, at prices
quoted in the magazine Iron Age. Prices received trended downward during
the year, from a high of about $40.82/Mg to $34.50/Mg, f.o.b. Gary, Indiana.
Freight charges have approximated $15.42/Mg, resulting in a net price at Ames
of $25.40 to $19.08/Mg.
Fees collected from deliveries to the processing plant are based upon
the type of vehicle used. Single rear-axle vehicles are charged $0.50 per
load, and multiple rear-axle vehicles are charged $1.00 per load. These
rates are applicable to all deliveries, regardless of source. From the data
in Table 30 there is some indication that fee collections are higher during
the warmer months, apparently attributable to increased deliveries by private
individuals rather than commercial trash haulers.
Noncash Revenues
This revenue item is derived from the valuation of the refuse burned as
a source of fuel. It is a noncash item since the refuse is delivered to the
municipally owned electric power generating plant that is adjacent to the ref-
use processing plant. Table 30 provides monthly revenue figures for the
amount of RDF used to generate electricity.
The derivation of a value for the RDF is difficult because of several fac-
tors. First of all, the Ames plant uses a bulk-density method of measuring
the amount of RDF delivered to the power plant; consequently precise measure-
ments of actual weight are not available. Second, the combustion efficiency
of the RDF versus coal is an essential element in arriving at a value, and
boiler test results on this subject are not yet complete. Finally, the
valuation of the RDF requires that consideration be given to the dollar
value of the regular fuel (in this case, coal) that the RDF replaces. This
entire matter will be given more detailed consideration during the course
of the study for the year 1977. Clearly, the many factors involved indicate
that RDF valuation will be unique to every operation and geographic location
and that the dollar valuation presented in this report should be used with
discretion for application to other locations.
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Summary of Revenue Credits
The average value of the RDF for the year was $8.60/Mg of refuse received
at the processing plant, or a total of $319,453. Cash revenues totaled
$128,714, an average of $3.47/Mg of refuse received at the processing plant.
Hence, total revenue credit was $448,167 for 1976, or $12.07/Mg of refuse
received by the solid waste processing plant. Comparison of these actual
figures with estimates developed prior to plant construction is shown below:
ACTUAL VERSUS ESTIMATED REVENUES PER MEGAGRAM
OF REFUSE PROCESSED
Estimated Actual
Fuel value of RDF $10.00 $8.60
Recovered materials $3.45-$6.30 $3.47
Megagrams of refuse processed 49,660 37,136
The value of ferrous metal scrap is at a low point in the market place. Prior
years have seen higher prices for scrap. As business activity increases,
value received for recovered material may improve due to increased ferrous
scrap prices. Also, the value of fuel credits per megagram of raw refuse
processed will increase due to an estimated 10 to 15% annual increase in coal
costs at Ames, Iowa. Also, the projected estimate of refuse volumes was made
during 1971 to 1973. This estimate was made using the best data available at
that time which showed refuse to be generated at the rate of 2.03 kg/capita.
Although population in the City of Ames and Story County, the county that in-
cludes Ames, has increased, the amount of refuse generated per capita has de-
creased. City of Ames data from 1971 show that nearly 1,000 Mg of refuse per
week was generated in the county. Data for 1976 show this amount to be ap-
proximately 715 Mg/week. Reasons for this significant decrease are unknown,
but it conforms with decreases being experienced across the nation.
Operating Expenses
Operating expenses incurred during 1976 by the refuse processing plant
are presented in Table 32. Also, presented in this table are operating cost
information, megagrams of refuse received, and calculations of operating
costs per megagram of refuse received.
The average operating cost per megagram received during the year, $30.98,
is considerably higher than the $16.91 estimated before the processing plant
was constructed. The critical factor here, though, is the volume of refuse
processed. Indeed, had the volume of refuse reached the expected level of
49,660 Mg, the cost factor would have been $23.00/Mg of refuse received, as-
suming no change in operating costs.
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TABLE 32. MONTHLY OPERATING EXPENSES AND COST PER MG OF REFUSE RECEIVED
AMES, IOWA, WASTE RECOVERY SYSTEM
1976
Month
January
February
March
April
May
June
July
August
September
October
November
December
Salaries^/
$ 10,611
10,961
12,051
14,409
10,853
12 , 14'.
13,676
13,571
14,563
12.160
10,480
8,194
All otherli/
$ 25,01)
43 , 188
40,040
30,195
59,720
34,541
1,856
13,451
24,207
41,717
30,551
23,915
Depreciations'
$ 29,489
29,489
29,489
29,489
29,489
29,489
29,489
29,489
29,489
29,489
29,489
29,489
Interest!/
$ 23,716 $
23,716
23,716
23,716
23,716
23,716
23,716
23,716
23,716
23,716
23,716
23.716
Total
88,827
107,354
105,296
97,809
123,778
99,890
68,737
80,227
91,975
107,082
94,236
85,314
Refuse
received
(Mg)
2 , 895
2,719
2,786
3,900
3,476
3,354
3,194
3,314
3,198
3,420
1,739
3,141
Operating
cost per
mcgag ram
$30.68
39.48
37.79
25.08
35.61
29.78
21.52
24.21
28.76
31.31
54.19
27.16
Total $143,673
$368,392
$353,868
$284,592 $1,150,525 37,136
$30.98
a/ Included within these figures are all employee wages paid during the year, plant management sal-
aries, and some allocation of salaries of the Public Works Department of Ames personnel based
on estimates of time devoted to the processing plant.
b_/ Includes all outside services retained, supplies, repairs to equipment, uniforms, etc. Data are
not available for a more specific breakdown.
£/ Departure from the accounting methods used by the City of Ames to develop total operating expense.
The city makes no allowance for the estimated useful life of the operating equipment, but rather,
expenses the annual principal payment on the debentures sold to finance the plant. Our opinion
is that the depreciation more accurately reflects the true expense of plant amortization. Depre-
ciation is calculated on a straight line basis.
df Not the actual interest paid by the City of Ames on the debenture financing, but is the annualized
total interest resulting therefrom, i.e., total interest to be paid over the life of the indebt-
edness divided by the number of years the debt will exist. In our opinion, this more realisti-
cally reflects the interest obligation. The use of actual-interest-paid would otherwise be con-
siderably higher during the first several years, then gradually diminish as the debentures are
redeemed.
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Detailed Analysis of Operating Expenses
This section of the report will include two separate parts. First, a
discussion on the fixed and variable expenses of plant operations will be
presented. Secondly, operating costs will be analyzed on each subsystem of
the plant.
Fixed and variable expenses, for purposes of this analysis--deprecia-
tion, equipment rental, insurance premiums, plant lighting, administrative
salaries, and interest charges are considered to be fixed; that is, the
absolute amount of expenses will remain unchanged relative to changes in vol-
ume throughput. All other expenses and salaries are considered to be vari-
able; that is, they can be expected to change directly proprotional to changes
in throughput volume.
For the year 1976, variable expenses were $411,049 or $8.88/Mg of refuse
received at the processing plant* Unfortunately, a completely detailed break-
down of the "all other" expenses is unavailable, but this expense category
accounted for 87.5% of the total operating expense. Salaries and wages were
$143,673, or 12.5% of the total operating expense. Based upon the amount of
refuse processed, the total labor portion of the expenses resulting in $3.87/
Mg of refuse processed.
An analysis of labor expenses for the period of June 1 through December
31, 1976, is presented in Table 33. For the entire year, the labor cost,
both direct and indirect, was $89.58 per plant operating hour and $115.19 per
actual processing hour. Obviously, the data are skewed upward because of the
2-week downtime period during the month of November after the fire.
TABLE 33. ANALYSIS OF SALARIES AND WAGE EXPENSE
(June 1 through December 31, 1976)
Month
June
July
August
September
October
November
December
Total
Total
salaries
and wages
12,144
13,676
13,571
14,563
12,160
10,480
8,194
84,788
Total
operating
($) hours
125.2
133.6
157.4
148.2
142.0
77.0
163.1
946.5
Actual
processing
hours
98.1
99.1
121.5
120.6
112.2
54.1
130.5
736.1
Cost per
operating
hour ($)
97.00
102.37
86.22
98.27
85.63
136.10
50.24
89.58
Average
Cost per
processing
hour ($)
123.79
138.00
111.70
120.75
108.38
193.72
62.79
115.19
Average
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An allocation of salary and wage expense by specific plant operation is
presented in Table 34* In this case, expense is allocated on the basis of
the average percent of labor hours during the study period to each operation.
Obviously, the allocated expense includes administrative labor as well as di-
rect. Figures of actual labor costs for each operation are unavailable, but
the figures in the table provide some indication of the proportionate share
of labor expense for each operation.
TABLE 34. ALLOCATION OF SALARY AND WAGE EXPENSE BY PLANT OPERATION
(June 1 through December 31, 1976)
Operation
Percent of
total direct
labor hours
Total
100.0
Attributable
salary and wage
expense ($)
General operations and shredder grates
Cleaning process area
Operating front- end loader
Tipping floor
Control room
Shredders and hammers
Secretarial and tour
Recovered metal
Janitorial
Maintenance
All other
22.2
16.7
11.8
9.6
9.1
4.1
4.0
3.6
3.3
3.2
12.4
18,823
14,160
10,005
8,140
7,716
3,476
3,392
3,052
2,798
2,713
10,513
84,788
A breakdown of the all other expense categories per hour of operation is
not presented in monthly tabular format because of the disparity between when
an expense was incurred and when it was paid, as in the case in the City of
Ames cash accounting procedure. However, using just the totals for the period
between June 1 and December 31, 1976, results in an all other cost of $179.867
hr of operation, and $231.27 per actual processing hour.
In total, including both labor and all other expense, the cost per hour
of operation was $269»44, and the cost per hour of actual processing was
$346.56. Unfortunately, these figures cannot be compared with other facili-
ties because of the unavailability of information.
Summary of Revenue and Expense
Table 35 presents a summary view of the financial operating results of
the processing plant for the year 1976. Total operating expenses for the year
105
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were $1,150,525 and revenue credits during the period were $448,721. The
quantity of refuse received at the processing plant was 37,136 Mg. For the
entire year, the net operating cost per megagram received averaged $18.90
varying from a low of $9.77 in the month of July, to a high of $38.94 in
November. If the November figures are not considered, because of the fire
that month, the average for the year is $17.07/Mg.
TABLE 35. SUMMARY OF FINANCIAL OPERATING RESULTS
Month
January
February
March
April
May
June
July
August
September
October
November^/
December
Total
Operating
cost ($)
88,827
107,354
105,296
97,809
123,778
99,890
68,737
80,227
91,975
107,082
94,236
85,314
1,150,525
Revenue
credit ($)
35,844
28,292
36,943
47,408
37,154
34,571
37,538
34,987
46,875
52,514
26,524
30,071
448,721k/
Refuse
received
(Mg)
2,895
2,719
2,786
3,900
3,476
3,354
3,194
3,314
3,198
3,420
1,739
3,141
37,136
Net operating
cost per
Mg of refuse ($)
18.30
29.08
24.53
12.92
24.92
19.47
9.77
13.65
14.10
15.96
38.94
17.59
18. 9(£/
a/ Fire in processing plant. Plant not processing for 2 weeks during cleanup
and repair.
bf Includes credits for RDF, dump fees, and recovered materials.
c/ $1,150,525 less $448,721 -f 37,136.
The net cost of disposal figure of $18.90 compares with an estimated
range of $0.96 to $1.89 calculated in 1974 during design and projected cost
studies, or 10 times higher than anticipated. To some extent, the differ-
ence can be attributed to the typically high expenses of any new facility
during early periods of operation. In addition, fire damage incurred dur-
ing the month of November not only ceased operations for 2 weeks, but re-
quired extensive extraordinary expenses to put the facility back into opera-
tion.
106
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If the net disposal cost is to be reduced, it is clear that operating
expenses need to be reduced while simultaneously increasing the volume of
refuse throughput. For example, a 10% reduction in operating expense would
reduce the net disposal cost to $15.80. If throughput volume were simulta-
neously increased 10%, net disposal cost could be further reduced to $14.36.
Significant inroads toward reducing the net disposal cost, cannot be achieved
until throughput volume is increased.
Reducing operating expenses must take into consideration the relatively
high proportion of fixed charges, however. Of the $1.15 million in 1976 ex-
penses, $739,476 are considered to be fixed, including annualized interest on
the debentures, equipment rentals, administrative salaries, insurance, equip-
ment depreciation, etc., or 56% of the total. Since nothing can be done to
reduce the fixed portion, any reductions must come from the variable portion
which is $411,049, including wages and variable operating expenses. As such,
a 20% reduction in total operating expense ($228,360), would necessitate a
45% reduction in the variable portion, a near impossibility.
Increases in the volume of throughput can have a dramatic impact on net
disposal costs, primarily because of its effect on reducing the per unit
fixed cost. The Ames plant was designed for a maximum capacity of about
725 Mg/day, operating on a two-shift per day basis. This translates into
about 362 Mg/day for a single shift, i.e., 8 hr/day. During the year of 1976,
the Ames plant averaged only 143 Mg/day (assuming 260 working days per year).
Hence, the plant was only operated at 20% of maximum capacity (at 725 Mg/day),
or just 40% of capacity on a single shift basis.
Net Cost of Net Electricity Generated
During the period of the study (June 1 through December 31, 1976), re-
cords were maintained enabling a calculation of the cost of the net electric-
ity generated by the refuse. The "net cost" figure is total costs less
revenues. The "net electricity" figures are electricity generated by the RDF,
less the amount of electricity consumed by the refuse processing plant. A
summary of the results reveals that the value of the RDF on a per kilowatt
hour basis was 3.37£, not including the operating cost of the power generating
plant. This compares to an equivalent cost of coal of about 1.40^/kw-hr which
the Ames power plant is presently paying. If the figures for the month of
November are omitted because of the extraordinary occurrence of the fire, the
net cost per kilowatt-hour for the period is 2.950. Table 36 presents the
values used to calculate these figures.
107
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TABLE 36. NET COST PER KILOWATT-HOUR OF NET ELECTRIC POWER GENERATED
June
July
August
September
October
November
December
Total
Net cost
of producing
RDF£/
$ 52,983
31,199
45,240
45,100
54,568
67,712
55,243
$352,045
Net electricity
generated
(kw-hr)
1,490,694
1,629,090
1,559,071
1,778,313
1,858,518
810,135
1,329,996
10,445,817
Cost per
kw-hr
(in cents)
4.38
1.92
2.90
2.54
2.94
8.36
4.15
3.37
Average
a/ Total operating cost, less revenue from the sale of recovered materials
and credit on the fuel value of RDF.
The 3.37^/kw-hr cost of fuel to generate electricity compares with the
rule of thumb figure for operating a electric generating plant of 2.0$/kw-hr
total cost including fuel maintenance, labor, etc. Two factors should be
considered, however: (a) this period of the refuse processing plant was the
first full year of operation, and (b) the plant is operating at only 407., of
capacity. Improvements in either of these two areas could reduce the cost
of the electricity generated by RDF.
108
-------
APPENDICES
o
v£>
APPENDIX A - MONTHLY PROUDCTION-REFUSE PROCESSING PLANT
TABLE A-l. MONTHLY PRODUCTION - AMES, IOWA, REFUSE PROCESSING PLANT
Weight (Mg)
Month
(1976)
January
February
March
April
May
June
July
August
September
October
November
December
Total
Raw Refuse
Processed
2,894.79
2,719.42
2,785.70
3,900.30
3,476.43
3,354.01
3,193.80
3,314.41
3,197.65
3,419.85
1,739.29
3,140.88
37,136.53
Glass
and Grit
28.31
7.24
16.92
56.06
14.08
4.20
56.29
7.67
4.52
22.01
0.00
0.00
217.30
Rejects to
Landfill
136.22
165.83
278.36
301.42
274.58
261.10
210.40
236.65
237.85
276.41
134.29
249.99
2,763.10
Fe -Metal
183.47
176.50
157.75
251.01
236 . 18
253.43
244.61
226.65
215.98
279.01
133.61
236.49
2,594.69
Non Fe -Metal
0.00
0.00
1.65
1.26
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.08
4.67
Wooden ips
67.80
39.45
29.28
28.96
23.14
28.43
25.06
7.69
12.66
22.06
0.00
11.16
295.69
RDF (by
Difference)^
2,478.99
2,330.40
2,301.74
3,261.59
2,928.45
2,806.85
2,657.44
2,835.75
2,724.96
2,820.36
1,471.39
2,643.16
31,261.08
a/ RDF by difference is incoming raw refuse less glass and grit, rejects, Fe-metal, Non Fe-metal, and
woodchips. Therefore, the RDF by difference also includes any plant material losses.
-------
TABLE A-2. MONTHLY PRODUCTION - AMES, IOWA, REFUSE PROCESSING PLANT
Month
(1976)
January
February
March
April
May
June
July
August
September
October
November
December
Average—'
Raw Refuse
Processed
100
100
100
100
100
100
100
100
100
100
100
100
100
Glass
and Grit
0.98
0.27
0.61
1.44
0.41
0.13
1.76
0.23
0.14
0.64
0.00
0,00
0.59
Rejects to
Landfill
4.71
6.10
9.99
7.73
7.90
7.78
6.59
7.14
7.44
8.08
7.72
7.96
7.44
Percent
Fe -Metal
6.34
6.49
5.66
6.44
6.79
7.55
7.66
6.84
6.75
8.16
7.68
7.53
6.99
Non Fe -Metal
0.00
0.00
0.06
0.03
0.00
0.00
0.00
0.00
0.05
0.00
0.00
0.003
0.01
Woodchips
2.34
1.45
1.05
0.74
0.67
0.85
0.78
0.23
0.40
0.65
0.00
0.36
0.79
RDF (by
Difference)-/
85.63
85.69
82.63
83.62
84.23
83.69
83.21
85.56
85.22
82.47
84.60
84.15
84.18
a/ RDF by difference is incoming raw refuse less glass and grit, rejects, Fe-metal, Non Fe-metal, and
woodchips. Therefore, the RDF by difference also includes any plant material losses.
b/ Average percent is calculated from total weight and is not an average of the individual months.
-------
APPENDIX B - DAILY VALUES OF RDF MOISTURE CONTENT AND HEATING VALUE
TABLE B. MOISTURE AND HEATING VALUE OF DAILY SAMPLES OF RDF
DISCHARGE FROM STORAGE BIN
(Samples taken by City of Ames and analysis by Ames Laboratory ERDA)
Heating Value
January ?
January 5
January 6
January 7
January £
January 9
January LO
January 12
January 14
January 15
January 16
January 17
January 19
January 20
January 21
January 22
January 23
January 24
January 23
January 26
January 27
January 23
January 29
January 30
January 31
February I
February 2
February 3
February 4
February 5
February 6
February 7
February 9
February 10
February 11
February 12
February 13
February 14
February 15
February 16
February 17
February 19
February 20
February 21
February 23
February 24
February 25
February 26
February 27
February 29
March 1
March 2
March 3
March 4
March 5
March 8
March 9
March 10
March 11
March 13
March 17
March 18
Marcn 23
March 25
Moiscure "
24.60
18.36
20.42
14.89
25.22
24.63
25.49
24.83
24.29
27.73
25.00
21.24
24.45
23.31
20.06
22.44
21.00
23.02
24.16
22.94
23.10
19.77
19.89
22.07
22.13
22.95
20.65
24.55
22.68
21.11
20.99
18.87
24.26
24.72
16.76
20.38
19.02
18.60
18.63
24.45
27.93
24.59
19.99
20.77
25.06
27.89
29.85
30.80
25.00
31.35
20.35
25.60
25.21
25.98
23.43
18.20
26.92
26.51
24.81
24.17
31.76
19.15
22.19
16.99
kJ/kg
As Received
13,891
14/544
14,931
13,607
13,007
13,105
13,479
13,921
13,637
12,874
13,656
14,103
13,735
13,975
15,538
14,175
14,898
13,823
14,070
13,549
14,424
14,996
14,947
15,540
13,493
13,591
13,723
12,853
13,514
13,816
15,289
14,440
12,484
13,340
14,168
13,500
13,791
13,388
13,877
12,728
12,260
12,314
13,837
13,840
14,019
11,797
11,530
11,374
13,030
13,786
15,380
13,047
12,093
12,651
13,342
13,898
12,111
12,239
14,130
13,093
10,939
15,826
13,309
13,575
kJ/k,i
Moist';r-T Free
18,423
17,815
18,762
15,938
17,394
17,388
18,090
18,519
18,012
17,814
18,208
17,906
18,180
18,222
19,137
18,276
18,358
17,957
18,552
17,712
18,756
18,691
18,656
19,941
17,328
17,639
17,295
17,036
17,478
17,514
U,350
' 17,798
16,482
17,720
17,020
16,956
17,029
16,448
17,054
16,847
17,012
16,329
17,295
17,463
13,707
16,360
16,436
16,436
17,374
20,082
19,937
17,536
16,169
17,091
17,424
16,990
16,573
16,655
18,793
17,266
16,030
19,575
17,105
16,353
(continued)
111
-------
TABLE B. (continued)
Date 1976
March 26
March 28
March 29
March 30
March 31
April 1
April 2
April 5
April 7
April 3
April 9
April 10
April H
April 12
April 13
April 14
April 15
April 17
April 18
April 19
April 20
April 21
April 22
April 23
April 24
April 26
April 27
April 28
April 29
April 30
May 1
May 2
May 3
May 4
May 6
May 8
May 9
May 10
May 12
May 13
May 14
May 15
May 16
May 17
May 19
May 20
May 21
May 24
May 25
May 26
May 27
May 28
May 29
May 30
June 1
June 2
June 3
June 5
June 6
June 9
June 10
June li
June 12
June 13
Moisture "7f
20.32
16.89
17.78
28.47
32.85
28.89
25.00
17.76
19.79
16.51
19.36
20.32
18.56
18.91
25.00
25.00
25.00
22.77
18.23
36 38
31.94
27.70
34.41
31.08
29.25
24.63
22.53
29.98
30.00
27.51
25.94
27.92
31.47
21.27
19.94
14.25
17.45
20.28
20.48
21.63
23.02
23.35
21.69
29.26
32.00
26.55
26.42
26.14
26.44
30.25
21.73
21.34
19.27
17.33
22.86
19.99
13.49
15.37
19.36
18.74
25.22
22.04
23.01
21.52
Heat
kJ/kg
As Received
13,395
14,142
14,175
11,972
10,725
11,770
13,886
14,012
13,156
13,321
12,153
13,130
12,551
12,405
11,530
12,398
13,449
12,300
12,523
11,093,
11,772
11,421
10,748
11,574
12,844
12,944
14,847
11,302
11,262
12,093
11,679
11,423
10,404
12,495
13,170
14,431
13,114
13,091
13,305
13,912
12,984
12,370
12,777
10,397
10,148
11,351
11,423
12,912
12,532
10,576
12,849
12,888
14 , 6 10
12,753
12,779
12,125
14,475
14,163
10,502
13,542
12,893
13,128
12,781
13,437
i-ia Vilue
kJ/kg
Moisture Free
16,312
17,016
17,240
16,737
15,972
16,551
18,515
17,038
16,402
16,554
15,071
16,533
15,411
15,297
15,373
16,530
17,932
15,926
15,315
17,436
17,296
15,796
16,387
16,794
18,154
17,174
19,165
16,141
16,039
16,682
15,769
15,348
15,182
15,371
16,450
16,829
15,886
16,421
16,731
17,751
16,366
16,138
16,316
14,698
14,924
16,135
15,525
17,481
17,037
15,163
16,416
16,385
18,097
15,427
16,566
15,135
16,732
16,735
13,023
16,665
17,241
16,839
16,601
17,122
(continued)
112
-------
TABLE B. (continued)
Heating Value
June 14
June 15
June [0
June 20
June 22
June 23
June 24
June 25
June 26
June 27
June 28
June 29
June 30
July I
July 2
July 3
July 4
July 5
July J
July 3
July 9
July 10
July 11
July 13
July 14
July 16
July IS
July 20
July 21
July 22
July 23
July 24
July 25
July 26
July 27
July 28
July 29
July 31
August 1
August 4
August 5
August 6
August 7
August 3
August 9
August 10
August 11
August 12
August 13
August 14
August 15
August 16
August 19
August 20
August 21
August 22
Moisture '
22.04
12.30
23.24
23.41
15.02
21.92
26.23
22.93
24.97
21.32
22.81
29.12
16.52
21.20
21.38
21.75
18.37
16.69
17.46
19.58
18.85
17.91
24.89
24.21
21.63
18.69
18.37
21.74
26.18
20.87
23.27
20.95
20.10
25.81
34.21
24.37
24.35
32.99
31.29
19.12
24.20
19.71
19.82
23.55
21.67
21.18
18.69
23.02
23.42
29.77
24.46
23.89
23.43
25.75
24.04
29.99
kJ/kg
As Received
12,195
15,140
13,033
11,553
15,540
13,249
12,177
12,495
12,500
12,377
11,904
11,656
13,900
13,037
13,200
13,198
13,268
15,061
13,572
13,356
14,137
14,242
11,865
12,116
13,579
14,198
12,342
12,419
11,723
13,447
12, '377
12,623
12,307
12,419
10,407
12,614
12,765
10,381
10,751
14,382
12,016
13,465
12,635
12,132
13,512
12,965
14,282
12,958
11,956
11,153
12,207
12,779
13,475
11,881
12.935
11,251
kJ/kg
Koisture Free
15,643
17,263
16,978
15,084
18,287
16,968
16,506
16,213
16,660
15,730
15,422
16,444
16,651
16,545
16,790
16,866
16,253
13,078
16,443
16,608
17,421
17,349
15,797
15,986
17,327
17,461
15,119
15,868
15,881
16,993
16,130
15,969
15,403
16,739
15,818
16,678
16,874
15,492
15,647
18,400
15,852
15,771
15,758
15,870
17,250
16,449
17,564
16,833
15,612
15,881
16,159
16,790
17,598
16,002
16,989
16,070
(continued)
113
-------
TABLE B. (continued)
Heating Value
August 23
August 25
August 26
August 27
August 28
August 29
August 31
September 1
September 2
September 3
September 4
September 5
September 6
September 7
September 8
September 10
September 11
September 12
September 13
September 15
September 16
September 17
September 18
September 19
September 20
September 21
September 22
September 23
September 24
September 25
September 26
September 27
September 28
September 29
September 30
October 1
October 2
October 3
October 4
October 5
October 7
October 8
October 9
October 10
October 11
October 12
October 13
October 16
October 17
October 18
October 19
October 20
October 21
October 22
October 23
Moisture
26.93
20.88
12.45
20.16
23.00
21.21
19.il
22.84
21.33
21.03
16.61
24.15
18.12
20.20
28.94
17.50
18.30
22.39
21.57
20.14
10.31
22.02
24.93
24.19
21.66
21.26
20.86
17.56
13.84
23.05
21.88
15.73
23.18
17.97
18.07
16.25
19.03
19.71
13.28
27.65
24.09
31.23
26.73
19.56
6.88
30.49
19.66
8.10
14.76
23.50
26.37
28.02
27.52
28.47
4.31
kJ/kg
As Received
12,414
13,388
14,742
13,137
12,607
12,774
14,217
12,923
13,475
12,139
13,926
12,398
13,668
13,426
11,932
15,210
14,296
11,128
13,784
14,230
15,866
13,654
12,437
11,996
13,516
13,607
13,216
14,407
14,386
12,670
13,135
15,205
12,284
15,261
14,528
14,163
13,714
13,551
15,731
11,974
13,451
11,604
12,125
14,007
16,970
9,678
14,198
15,584
15,598
13,014
13,477
11,607
12,307
11,470
14,177
kj/ki.
Moisture Free
16,989
16,922
16,839
16,454
16,373
16,213
17,641
16,749
17,128
15,372
16,700
16,345
16,692
16,324
16,792
18,436
17,498
14,431
17,575
17,319
17,689
17,509
16,567
15,823
17,253
17,281
16,700
17,476
16,697
16,465
16,814
18,043
15,990
18,604
17,732
16,911
16,937
16,878
18,140
16,550
17,720
16,874
16,549
17,413
18,224
13,924
17,672
16,958
18,299
17,012
18,303
16,125
16,980
16,035
14,816
(continued)
114
-------
TABLE B. (continued)
Dace 1Q76
October 24
October 25
October 26
October 27
October 23
October 29
October JO
October 31
November 2
November 3
November 4
Noveaber 5
November 6
November 7
November 23
November 24
November 25
November 26
November 27
November 29
November 30
December 1
December 2
December 3
December 4
December 5
December 6
December 3
December 9
December 10
December 11
December 12
December 13
December 14
December 15
December 16
December 19
December 20
December 22
December 23
December 24
December 25
December 27
December 28
December 29
December 30
December 31
Mean "K
Number of samples, n
Standard deviation, Sx
Moisture "
19.65
19.83
27.14
16.67
25.32
23.32
17.39
27.94
17.85
18.60
26.40
26.62
23.63
29.19
11.72
16.04
12.63
16.97
25.38
20.25
24.04
18.34
26.56
24.35
23.40
22.63
.17.77
12.05
26.24
21.35
26.35
23.97
17.97
24.12
12.97
22.40
25.33
16.50
17.25
21.93
18.56
25.32
13.40
9.78
21.95
15.78
20.40
22.23
286
i.864
Hejtine
kJ/kg
As Received
13,754
14,598
12,079
14,842
11,844
12,646
13,568
10,758
15,500
14,130
14,896
14,489
13,193
13,963
16,645
14,493
15,912
13,528
13,407
13,775
14,077
12,584
11,642
13,091
13,040
11,856
15,279
16,052
12,677
12,947
11,770
12,721
15,361
13,093
14,589
13,312
10,962
16,301
14,603
13,637
11,302
11,239
14,475
15,712
12,860
14,891
14,019
13,188
286
1,297.2
VAlue
kj/kg
Xoisture Free
17,117
18,209
16,578
17,854
15,860
16,493
16,424
14,929
18,863
17,359
20,239
19,745
17,275
19,719
18,855
17,262
18,223
16,293
17,967
17,272
18,532
15,505
15,852
17,304
17,023
15,323
18,581
18,251
17,186
16,461
15,980
16,731
18,726
17,255
16,763
17,154
14,681
19,522
17,647
17,468
13,878
15,050
16,715
17,415
16,477
17,894
17,612
16,967
286
1,141.0
Doefficient of variation,
CV '£/
21.88
9.34
6.72
•;'/ is the standard deviation expressed as a percent of the nean.
115
-------
APPENDIX C - TABULATION OF INFORMATION ON EQUIPMENT
AND FACILITIES EVALUATION
GLOSSARY OF TERMS—USED IN DAILY ACTIVITY LOG-TABLE C-l
RDF
(C-l); (C-2), etc.
High-Pressure Limit Switch
Change Trailers
Refuse-derived fuel.
The letter and number in the parentheses
refer to the designation on the flow di-
agram.
The pneumatic conveying line from the
processing plant to the storage bin is
fitted with a pressure sensor adjacent
to the blower. If a clog of RDF in the
line starts to form there will be an
increase in the pneumatic conveying line
pressure. This increase in line pressure
is detected by the sensor which activates
a switch to stop all conveyors. This
prevents the rotary air lock from feed-
ing more RDF into the pneumatic line
which could cause a major plug in the
line. The conveyors cannot restart un-
til the conveying line has cleared it-
self and the pressure is lowered. Set
point on the sensor is approximately
17.2 kPa (2.5 psi).
Fe-metal is conveyed to bulk material
trailers. When a trailer is full, the
plant is shut down to remove the full
trailer and replace it with an empty
trailer. Glass, non-Fe-metal, and re-
ject material are stored in holding
bins, and no plant downtime is necessary
to load out these materials.
116
-------
TABLE G-la. DAILY RECORD OF REFUSE PROCESSING PLANT ACTIVITY FOR THE MONTH OF JUNE 1976
Hay ll.-iy of Processing
(June 1"76) Week nay-Hours^' Clock Time
1 Tuesday 17.0 8:00 a.m.
3:00 p.m.
20 min
1:00 a.m.
2 Wednesday 9.0 8:00 a.m.
8:00-9:30 a.m.
20 min
5:00 p.m.
3 Thursday 11.0 7:00 a.m.
6:00 p.m.
4 Friday 11.0 7:00 a.m.
6:00 p.m.
7 Monday 9.0 8:00 a.m.
5:00 p.m.
8 Tuesday 8.5 8:00 a.m.
20 min
20 min
3:00-4:00 p.m.
4:30 p.m.
9 Wednesday 8.5 8:00 a.m.
10:20 a.m.
20 min
1:50-2:20 p.m.
4:30 p.m.
10 Thursday 8.5 8:00 a.m.
4:30 p.m.
L)e *scr i ft i on
Pi ant start. -up •
ADS drag conveyor drive motor burned out and taken to shop for rewinding. This is first time
thi s has happened .
ADS motor reinstalled and processing started.
Changed trailers-
Plant shutdown .
Plant start-up.
Bearing temperature sensor on shredder 1 indicated hot temperature. Plant shutdo-.n to ch^c-'. out
bearing and sensor.
Changed trailers.
Plant shutdown.
Plant start-up.
P I an t shu t down .
Plant start-up.
Plant shutdown.
Plant start-up.
Plant shutdown.
Plant start-up-
Changed trailers
Front-end loader used to load scrap metal in dump truck.
Pneumatic conveyor rotary air lock feeder plugged.
Plant shutdown .
Plant start-up- Not enough raw refuse accumulated to start processing.
Processing commenced.
Changed trailers.
Vibraring conveyor (C-2) receiving shredder I discharge plugged.
Plant shutdown.
Plant start-up.
Plant stmi xlovn •
(continued)
-------
TABLE C-la. (continued)
M
oo
Day
(Jung 1976)
11
14
15
16
17
18
19
21
•"•^•^ ^ ««^ •MB^BBM^.W.MMMWHnMMBI^HMM^H^HMIW^BMIM
Day of Processing
Week Day Hours- Clock Time
Friday 15.5 8:00 a.m.
8:25 a.m.
4:30 p.m.
10 mln
5 min
7:30-7:50 p.m.
11:30 p.m.
Monday 0 8:00 a.m.-
4:00 p.m.
Tuesday 8.7 6:00 a.m.
2:40 p.m.
Wednesday 0
Thursday 7.5 5:00 p.m.
7:30 p.m.
3:00 a.m.
Friday 0
Saturday 3.9 1:35 p.m.
5:30 p.m.
Monday 1.7 10:30 a.m.
12:10 p.m.
""""•"""•^•'''•'^""""^'•'•"^^ — ~-~ — ' ' • • - H i • -
l)(";cr ipL ion
Pl.mt .start-up.
Firr in ADS Can motor. Processing slopped.
Processing resumed.
Feed hopper to belt conveyor (C-3) from shredder 1 to 2 plugged.
Pneumatic conveyor high-pressure limit switch activated three Limes.
Changed trailers.
Plant shutdown.
Decision not to process refuse to allow Atlas bin to be emptied and cleaned. Lubrication and
maintenance check of plant.
Plant start-up.
ADS drag conveyor drive motor burned out and taken to shop for rewinding. Second time for this
occurrence. Plant shutdown for balance of day.
Ho operation because waiting £or ADS motor from shop. Atlas bin shutdown due to loose rollers
on sweep conveyor.
ADS drag conveyor motor repaired.
Plant start-up.
Seven flights came loose from ADS conveyor and drag conveyor motor burned out for the third time.
Believe motor burnout due to motor overload thermal relay not tripping circuit breaker. Plant
shutdown. Motor sent to shop for repair.
No processing. Repair of ADS drag conveyor and motor.
Plant start-up. Processing backlog of refuse.
Plant shutdown.
Plant start-up.
Screw conveyor feeding pneumatic convoyor system plugged and drive motor burned out. Motor sent
to shop to bo rewound, plant shutdown. Raw retuse trucks routed to landfill.
(continued)
-------
TABLE G-la. (continued)
Bay
(June 1"76)
22
Tuesday
Processing
Day-Hours-^
19.7
I-1
VO
23
Wednesday
8.0
Clock Time De-script Ion
10:30 ;i.m. Screw conveyor motor repaired and rcinsLallrd.
11:00 a.m. Plant start-in.-.
1:35 p.m. Slopped proc
-------
TABLE C-la. (continued)
(June l°76)
J3
Wrok
Friday
Processing
Day-Hours-' Clock Time
Drscr i pi i on
Prior lo start -up, p/'tiornl c 1 r.inup, maintenance on aluminum separ-tt £01
i systems, an-) cleaned
3.8
26
28
Saturday
Monday
9.0
29
Tuesday
8.5
30
Wednesday
4.5
12:10 p.m.
12:35-12:50 p.m.
1:40-1:45 p.m.
2:10-2:20 p.m.
3:05-3:20 p.m.
4:00 p.m.
5 min
8:30 a.m.
30 min
25 min
10:00-11:00 a.m.
11:10-11:15 a.m.
1:50-2:30 p.m.
3:15-4:15 p.m.
5:30 p.m.
8:30 a.m.
9:00-9:10 a.m.
5 min
9:40-9:45 a.m.
11:00-12:30 p.m.
20 min
12:30 p.m.
5 min
20 min
5:00 p.m.
11:45 a.m.
11 :55-12:00 p.m.
Z« min
15 min
4:15 p.m.
and aligned screw conveyor motor.
Plant start-up.
ADS heavies bolt conveyor (C-13) jammed.
Emergency stop button in-pi.-int activated by pile-up oC rclusc.
Raw refuse in-foed conveyor (C-l) jammed.
Changed trailers.
Plant shutdown at request of power plant due to loose roller on Atlas bin sweep conveyor.
Plumbing contractor changed galvanized water pipe to copper because of hardness of water.
No processing. General maintenance and all motors cleaned.
172 private automobiles delivered raw refuse.
Five employees in work ere'*
prior to start-up. Pumped up low tire on end loader.
Plant start-up.
Magnetic belt down seven times.
Raw refuse in-feed conveyor (C-l) jammed five times.
Repaired flight on conveyor (C-l) which had sheared two bolts.
Fueled front-end loader.
Atlas bin had plugged drag conveyor.
Changed trailers and fueled front-end loader (loader had run out of fuel).
Plant shutdown.
Plant start-up.
Replaced thread on raw refuse in-feed conveyor (C-l) bearing.
Shutdown due to pneumatic conveyor high-pressure limit switch.
Conveyor (C-l) jammed.
Repaired conveyor (C-l) due to bent flight caused by sheared bolt and repaired front-end
loader hydraulic system.
Wood chipper jammed.
Commenced processing again.
Conveyor (C-l) jammed three times.
Pneumatic conveyor high-pressure limit switch activated 15 times.
plant shutdown.
Prior to start-up replaced bol.h existing metal shredder curtains with rubber curtains.
Constant impact of refuse against metal curtains caused them to open occasionally. Felt
that rubber would be a better curtain material.
Plant start-up.
Hopper feeding belt convryor (C-1) from shredders 1 to 2 plugged.
Pneumatic conveyor hi f.ii-prcssure limit switch activated.
Haw refur.e in-feed conveyor (C-1) jammed.
Plant shutdown due to broken flight on ADS drag conveyor and broken "A" frame 4t bottom eF
conveyor.
a/ Processing day-hours is time span from first plant start-up to last plant shutdown, which is the time period the plant tmtsl be fully staffed. Process-
ing day-hours docs not include maintenance and cleaning hours prior to plant start-up and after plant shutdown. Also actual hours spent shredMinj;
refuse is less than processing day-hours due to various categories of downtime.
-------
TABLE C-lb. DAILY RECORD OF REFUSE PROCESSING PLANT ACTIVITY FOR THE MONTH OF JULY 1976
(
n.iv
.July 1";c>>
O.w
Hi;
nf
k
Process!
ll.i^--!lour
nf
•d' Clock Tune
Oc^cript ) on
I 'ItiursUay l'rf->r to start-up two workmen aligned chain on ADS drag conveyor.
7.9 12:35 p.m. I'l.iut start-up.
1:35-2:15 p.m. changed trailers.
5:40-6:00 p.m. Changed trailers.
15 min Raw refuse in-feed conveyor (C-l) jammed three times.
10 min Pneumatic conveyor high-pressure limit switch activated twice.
8:30 p.m. Plant shutdown.
2 Friday 9.9 6:35 a.m. plant start-tip.
20 min Raw refuse in-feed conveyor (C-l) jammed four times.
7:35-7:40 a.m. ADS feeder motor overload relay activated.
8:25 a.m. Plant shutdown due to lack o£ raw refuse and metal and reject trailers full.
10 min Loaded scrap metal into dump truck with front-end loader.
10:30 a.m. Resumed processing.
10 min Conveyor (C-l) jammed three times.
10:50-11:15 a.m. Repaired two broken bolts on conveyor
-------
TABLE C-lb. (continued)
Pay O.iy of
(July 1976) Week
8 Thursday
Friday
Procossi np
4.7
5.6
Clock
12
Monday
7.3
NJ
13
Tuesday
8.0
11:40 n.m.
1:10-1:15 p.m.
1:25-1:55 p.m.
4:20 p.m.
10:45 a.m.
11:05-11:10 a.m
11:45-12:55 p.m
1:05-1:15 p.m.
3:15-4:20 p.m.
15 min
4:20 p.m.
8:00 a.m.
8:10-8:20 a.m.
8:25-9:15 a.m.
9:15-11:45 a.m.
1:45-1:50 p.m.
5 min
3:15 p.m.
5:30 p.m.
10:15 p.m.
11:00 p.m.
10:10 a.m.
12:10-12:25 p.m.
1:10-1:13 p.m.
20 min
3:00-3:40 p.m.
3:40-3:55 p.m.
4:25-5:00 p.m.
6:10 p.m.
riant start-up.
Pneumatic conveyor high-pressure limit switch activated four times.
Changed trailers.
Plant shutdown.
Plant start-up.
ADS feed belt conveyor (C-6) motor overload relay activates.
Repaired raw refuse in-feed conveyor (C-l) and broken drive pin on conveyor (C-l).
Cleaned screen on ADS vibrating feeder.
Changed trailers. Delay due to plant personnel working on paper baler construction.
Conveyor (C-l) jammed four times.
Plant shutdown.
Plant start-up.
Feed hopper to belt conveyor (C-3) from shredders 1 to 2 plugged.
ADS feeder plugged.
Repaired hole in pneumatic conveyor line.
ADS feeder plugged.
In-feed conveyor (C-l) jammed.
Explosion in Shredder 1 . Plant shutdown. Flames passed along belt conveyor (C-3) to shredder 2
causing second explosion in shredder 2. Flames continued to ADS drag conveyor. Plant employees
immediately fought fire with hoses. Ames Fire Department arrived in approximately 5 min. Raw
refuse delivery trucks routed to landfill.
Fire declared dead. All raw refuse pulled out of in- feed conveyor (C-l) and thoroughly soaked with
water and later hauled to landfill. Work continued to clean up area and unclog refuse filled
plant drains. No damage found.
Plant equipment started and checked out. All worked well.
All personnel left plant except for one man to maintain fire watch with pump.
Raw refuse delivery trucks routed to landfill from 3:15 to 4:00 p.m.
Plant start-up.
Shear pin broke in raw refuse in-feed conveyor (C-l).
Pneumatic conveyor high-pressure limit switch activated.
Conveyor (C-l) jammed 17 times due to brush in raw refuse.
Change trailers.
Realigned magnetic belt relay.
AliS feeder motor overload activated.
Plant shutdown.
(continued)
-------
TABLE G-lb. (continued)
flay
(July 1976)
14
Wednesday
Processing
Day-Hours'^
6.3
15
Thursday
6.9
CO
U>
16
Friday
6.8
19
Monday
8.4
Clock Tlmr
Description
H):(K) a.m. Plant start-up.
11:30-12:10 p.m. Repaired two broken bolts on raw refuse in-feed conveyor (C-l); lost two bolts.
12:55-11:10 p.m. Belt conveyor (C-6) to ADS Jamned due to steel in refuse.
1:10-1:25 p.m. Stopped operation to unload freezer from delivery vehicle.
3:55-4:10 p.m. Vibrating conveyor (C-2) receiving refuse from shrrddnr 1 plugged.
4:20 p.m. Plant shutdown.
(Records analyzed show front—olid loader consumos an average 2.5 p/ll. of dicsrl fuel por lir)
9:30 a.m. Plant start-up.
9:55-10:20 .i.m. Vibrating conveyor (C-2) receiving refuse from shredder 1 plugged due to large pieces of cardboard.
5 min pneumatic conveyor high-pressure limit switch activated.
20 min Raw refuse in-feed conveyor (C-l) jammed eight times.
2:45-3:10 p.m. Change trailers.
3:15-3:45 p.m. Belt conveyor (C-3) from shredder 1 to shredder 2 plugged at shredder 2.
4:25 p.m. Plant shutdown.
9:50 a.m.- Plant start-up.,
10:15-10:27 a.m. Refuel front-end loader.
10:34-10:39 a.m. Magnetic belt separator plugged.
10:46-10:58 a.m. Cleared wire caught in Fe-metal system belt conveyor (C-ll and C-12).
11:46-11:49 a.m. Cleared wire caught in conveyor (C-12).
2:20-3:15 p.m. Change trailers.
3:50 p.m. ADS vibrating feeder plugged.
15 min Raw refuse in-feed conveyor (C-l) jammed seven times.
4:35 p.m. Plant shutdown.
8:20 a.m. Plant start-up.
8:27-8:41 a.m. Fe-metal belt conveyor (C-13) plugged.
9:00 a.m. ADS heavies belt conveyor (C-7) plugged.
9:18-12:55 p.m. Shutdown to check shredder 1 bearing.
2:13-2:46 p.m. Shutdown to check equipment.
3:00 p.m. Fe-metal belt conveyor (C-13) plugged.
10 min In-feed conveyor (C-l) plugged five times.
3:40-3:45 p.m. Ans heavies felt conveyor (C-7) plugged.
4:45 p.m. Plant shutdown.
(continued)
-------
TABLE C-lb. (continued)
Day
(July 1976)
20
Day o f
Ui-ck
Tuesday
Processing
Day-Hours^/
9.0
21
Wednesday
8.8
22
26
Thursday
Friday
Monday
6.7
4.3
8.0
Clock Time
9:55 a.m.
10:55-11:04 a.m.
11:55-12:00 p.m.
12:10-12:15 p.m.
1:55 p.m.
2:48-5:10 p.m.
6:20-6:25 p.m.
6:55 p.m.
6:55 a.m.
9:25-9:30 a.m.
9:40-10:02 a.m.
10:17-12:47 p.m.
1:45-2:07 p.m.
3:00-3:20 p.m.
4:18 p.m.
9:40 a.m.
17 min
1:40-2:49 p.m.
3:00-3:45 p.m.
4:23 p.m.
7:10 a.m.
7:10-7:20 a.m.
7:30-7:32 a.m.
8:00-10:00 a.m.
5 min
7 min
23 min
3:15-3:40 p.m.
4:10 p.m.
IH-sr.ripLion
Prior to plant n La rt. -up welded repairs on front end loader bucket, r--p ' ' i '--I h.in'IriiH on t.i-v
refuse in-feed conveyor (C-l), aluminum separation system belt convoyur «;-?Oi, nnd leaks in wat^r
system.
_Plant start-un.
ADS drag conveyor motor overload relay activated.
Magnetic belt separator stalled.
Stopped operations to remove gasoline can from raw refuse.
Iioadcd dump truck.
Repair ADS drag conveyor. Seven flights lost.
Pneumatic conveyor high-pressure limit switch activated.
Plant shutdown.
Plant start-up.
Fc-mct.il belt conveyor (C-13) plugged tail pulley.
Repaired loose bolt in front-end loader bucket.
Bearing manufacturer checking bearings.
ADS drag conveyor motor overload relay activated. ADS feeder plugged.
Changed trailers.
Plant shutdown.
Plant start-up.
Pneumatic conveyor high-pressure limit switch activated six times.
Check out equipment.
ADS drag conveyor plugged.
Plant shutdown.
Plant operated with no difficulty. Start and stop times not recorded.
taken from shredder running hours meter.
Plant start-up.
Conveyor belt (C-3) shredder 1 to 2 had difficulty in starting.
Magnetic belt separator plugged.
Changed trailers. Repair hydraulic hose on front-end loader.
Magnetic belt separator plugged three times.
Raw refuse in-feed conveyor (C-l) jammed three times.
Pneumatic conveyor high-pressure limit switch activated 17 times.
Changed trailers.
Plant shutdown.
Processing time
(continued)
-------
TABLE G-lb. (continued)
Day
(July 1976)
27
My of
Week
Tuesday
Processing
Day-Hours-^
12.8
28
Wednesday
4.3
Ul
29
Thursday
7.9
30
Friday
18.3
Clock Tlmr II.-M rl|.l ion
10:10 a.m. Plant start-up.
4 min Pneumatic conveyor high-pressure limit switch activated twice.
11:00 a.m.- Shutdown plant to work on Atlas bin. Sweep conveyor loose and mistracking.
3:00 p.m.
5 min Raw refuse in-feed conveyor (C-l) jammed twice.
5:29-6:55 p.m. Shutdown plant for dinner.
6:55-7:05 p.m. Fe-metal rejects belt conveyor (C-l) jammed at tail pulley.
10 min Conveyor (C-l) jammed five times.
15 min Pneumatic conveyor high-pressure limit switch activated seven times.
8:30-9:00 p.m. Changed trailers.
9:00-9:15 p.m. ADS feeder plugged.
5 min Fe-metal belt conveyor (C-13) plugged.
11:00 p.m. Plant shutdown.
11:47 a.m. Plant start-up.
9 min Raw refuse in-Ceed conveyor (C-l) jammed five times.
12 min Pneumatic conveyor high-pressure limit switch activated eight times.
3:07 p.m. Plant shutdown.
ADS inspected by manufacturer. Discovered that the drag conveyor constructed wrong. The re-
turn sprocket and belt tension adjustment sprocket had been reversed, allowing shredder refuse
to pack in the feeder and force the chain flights out of alignment. This misalignment over-
stressed the flights and caused their eventual breakage. Replacement with the correct sprockets
by the manufacturer was scheduled for Saturday, July 31, 1976.
8:38 a.m. Plant start-up.
9:05-9:20 a.m. ADS vibrating feeder plugged.
9:43-9:50 a.m. Magnetic belt separator plugged and pneumatic conveyor high-pressure limit switch activated.
10:15-10:20 a.m. Pneumatic conveyor high-pressure limit switch activated.
11:20-11:30 a.m. Belt conveyor (C-6) to ADS stalled.
11:47 a.m.- Plant shutdown for lunch and repair of fire protection system piping.
2:20 p.m.
2:30-2:35 p.m. Fe-metal belt conveyor (C-13) plugged.
2:50-3:00 p.m. ADS heavies bucket elevator (£-1) plugged.
3:15-3:30 p.m. Pneumatic conveyor high-pressure limit switch activated.
21 min Raw refuse in-feed conveyor jammed nine times.
15 min Pneumatic conveyor high-pressure limit switch activated.
3:40-3:45 p.m. ADS heavies belt conveyor (C-7) plugged.
3:55-4:00 p.m. Belt conveyor (C-6) to ADS stalled.
4:30 p.m. Plant shutdown.
8:20 a.m. Plant start-up
8:50-9:05 a.m. ADS draj* conveyor plupRp.d.
10:30 a.m. Plugged shredtlcr 2. Cleaned out plug and changed hammers. Changed trailers. Plant shutdown.
9:07 p.m. Plant start-up.
2:35 a.m. Plant shutdown on Saturday, July 31.
a/ Processing day-hours is time span from first plant start-up to last plant shutdown, which is the time period the plant must be fully staffed. Process-
~~ ing day-hours does not Include maintenance and cleaning hours prior to plant start-up and after plant shutdown. Also actual hours spent shredding
refuse is less than processing day-hours due to various categories of downtime.
-------
TABLE C-lc. DAILY RECORD OF REFUSE PROCESSING PLANT ACTIVITY FOR THE MONTH OF AUGUST 1976
Day
(August 1976)
Day of
Week
Monday
Tuesday
Wednesday
Day-Hours^
Processing
-Hour
0.5
2.1
11.8
rO
Thursday
11.3
Clock Time
9:25 a.m.
9:40-9:42 a.m.
9:45 a.m.
7:10 a.m.
8:55-9:00 a.m.
N.R.
9:15 a.m.
6:10 a.m.
6:55-7:00 a.m.
7:30-7:50 a.m.
9:30-9:40 a.m.
10:40-11:05 a.m.
12:40-12:45 p.m.
4:05-4:30 p.m.
N.R.
N.R.
5:55 p.m.
N.R.
8:20 a.m.
9:20-9:40 a.m.
11:20-12:00 p.m.
12:25-12:27 p.m.
12:57-1:00 p.m.
1:43-1:45 p.m.
1:53-3:05 p.m.
3:10-4:50 p.m.
5:45-5:50 p.m.
6:50-6:55 p.m.
N.R.
N.R.
7:40 p.m.
Description
Plant start-up.
ADS scalping roll motor overload relay activated.
Plant shutdown. ADS drag conveyor became misaligned and nine flights broken. Shut-
down for the day to repair drag conveyor. Also, maintenance performed on Atlas bin
sweep conveyor.
Plant start-up.
Magnetic belt separator plugged.
Raw refuse In-feed conveyor (C-l) jammed six times.
Plant shutdown.
Time not recorded.
Plant start-up.
Raw refuse In-feed conveyor (C-l) motor overload relay activated.
Fe-metal belt conveyor (C-10) plugged with paper.
Magnetic belt separator stopped.
Changed trailers.
Belt conveyor (C-6) to ADS tall pulley Jammed.
Changed trailers.
Pneumatic conveyor high-pressure limit switch activated eight times.
Conveyor (C-l) jammed 42 times.
Plant shutdown.
Time not recorded.
Plant start-up.
Fire in primary metals trap.
Plant shutdown.
Magnetic belt separator stopped.
Magnetic belt separator stopped.
Magnetic belt separator stopped.
Belt conveyor (C-6) to ADS motor overload relay activated and tail pulley jammed.
Changed trailers. Removed bed spring wound around front-end loader axles.
Magnetic belt separator stopped.
Magnetic belt separator stopped.
Pneumatic conveyor high-pressure limit switch activated four times. Time not recorded.
Raw refuse In-feed conveyor (C-l) jammed nine times. Time not recorded.
Plant shutdown.
(continued)
-------
TABLE C-lc. (continued)
.(August
nay of
Week
Friday
Process Inp,
12.6
Saturday
Monday
7.6
N>
10
Tuesday
6.5
11
Wednesday
4.2
Clock Time Description
6:10 a.m. Plant start-up.
6:40-6:45 a.m. Magnetic belt separator stopped.
7:10-7:45 a.m. Raw refuse in-feed conveyor (C-l) motor overload relay activated.
7:20-7:25 a.m. Magnetic belt separator stopped.
7:45-7:50 a.m. Magnetic belt separator stopped.
8:50-11:30 a.m. Conveyor (C-l) motor overload relay activated. Replaced loose bolts in conveyor (C-l).
Repaired hole In magnetic belt separator. Loaded scrap metal truck.
12:30-1:20 p.m. Changed trailers.
1:20-1:30 p.m. Added oil to front-end loader.
N.R. Conveyor (C-l) jammed 28 times. Time not recorded.
N.R. Pneumatic conveyor high-pressure limit switch activated three times. Time not recorded.
6:45 p.m. Plant shut down.
Worked 3.5 hours changing some of the hammers in the first stage shredder.
8:30 a.m. Plant start-up.
10:00-10:30 a.m. Changed trailers.
1:00-1:45 p.m. Shut down at request of power plant.
d.R. Pneumatic conveyor high-pressure limit switch activated five times. Time not recorded.
N.R. Raw refuse in-feed conveyor (C-l) Jammed 10 times. Time not recorded.
4:05 p.m. Plant shutdown.
7:05 a.m. Plant start-up.
7:25-7:55 a.m. Changed trailers.
11:40-12:05 p.m. Refueled front-end loader.
1:05-1:20 p.m. Fe-metal belt conveyor (C-12) jammed.
N.R. Raw refuse in-feed conveyor (C-l) jammed eight times.
1:35 p.m. Plant shutdown.
Before plant start-up Installed a screen around the second stage shredder motor. Also,
changed some of the hammers in the first stage shredder. This was a lengthy job because
the hammers and the shaft seemed to be rusted together. Hammer change required 3.5 hr
Saturday and 4 hr Wednesday for 7.5 hr total.
1:35 p.m. Plant start-up.
1:45-1:55 p.m. ADS heavies belt conveyor (C-14) jammed.
2:30-2:55 p.m. Changed trailers.
4:45-5:00 p.m. Replaced broken shear pin on raw refuse in-feed conveyor (C-l).
5:00-5:25 p.m. Removed wire wound around front-end loader drive shaft.
5:25-5:45 p.m. Bent fliRht on ADS drag conveyor.
5:45 p.m. riant shut down.
(continued)
-------
TABLE C-lc. (continued)
00
D8)r OB/ Of Processing
(August. 1976) week Day-Hours'1 Cl»l'k Time
12 Thursday 10.3 6:10 a.m.
7:40-7:50 a.m.
9:25-9:50 a.m.
2:20-2:25 p.m.
4:00-4:10 p.m.
30 mln
5 min
4:25 p.m.
13 Friday 6.3 9:10 a.m.
9:30-9:35 a.m.
9:40-9:45 a.m.
11:45-12:55 a.m.
10 mln
15 mln
4:30 p.m.
16 Monday 7.7 8:20 a.m.
3 mln
9:00-9:25 a.m.
10:20-11:05 a.m.
12:30-12:35 p.m.
1:30-1:35 p.m.
2:50-2:55 p.m.
3:05-3:20 p.m.
3:25-3:35 p.m.
20 mln
4:00 p.m.
17 Tuesday
7.7 11:20 a.m.
11:20-12:20 p.m.
1:05-2:05 p.m.
6:35-6:40 p.m.
20 mln
N.R.
7:00 p.m.
Description
IM.int Atnrt-np.
SrraiRht-ened bent flight on r.iw refuse in-feed conveyor (C-l).
Changed trailers.
Magnetic belt separator stopped.
Refueled front-end loader.
Conveyor (C-l) jammed 24 times.
Pneumatic conveyor high-pressure limit switch activated seven times.
Plant shutdown.
Plant start-up.
Fe-metal belt conveyor (C-ll) jammed.
ADS heavies belt conveyor (C-7) plugged.
Belt conveyor (C-6) to ADS jammed.
Raw refuse in-feed conveyor (C-l) jammed seven times.
Pneumatic conveyor high-pressure limit switch activated seven times.
Plant shutdown.
Plant start-up.
Pneumatic conveyor high-pressure llratt switch activated once.
Changed trailers.
Belt conveyor (C-3) shredders 1 to 2 jammed due to piece of wood stuck in head pulley.
Conveyor (C-3) plugged.
Conveyor (C-3) plugged.
ADS heavies belt conveyor (C-14) jammed.
Conveyor (C-3) plugged.
Conveyor (C-3) plugged
Raw refuse in-feed conveyor (C-l) jammed 14 times.
Plant shutdown.
Before plant start-up changed wear back elbow on pneumatic conveying line at Atlas bin
cyclone. Also, worked on shredder 2 curtain In In-feed throat because believe this to
be cause of conveyor (C-3) pluggage (refuse backing up on conveyor).
Plant start-up.
Cleaned ADS surge bin of wet material.
Changed trailer. Delivery blocked by crane.
Raw refuse In-feed conveyor (C-l) motor overload relay activated.
Conveyor (C-l) jammed 12 times.
Pneumatic conveyor high-pressure limit switch activated once. Time not recorded.
Plant shutdown.
18
Wednesday
No processing. Changed chain and flights in ADS drag conveyor. Cleaned plant.
Drag conveyor work completed hy 3:00 p.m. and ran equipment check. Welded angles
in primary shredde-r until 1:00 a.m.
(continued)
-------
TABLE C-lc. (continued)
my pay of
(August 1976) Week
19
Thursday
Process tng
Day-Hours^'
10.2
20
Friday
3.8
N>
23
Monday
8.7
Tuesday
11.3
7:20 a.m.
7:25-7:40 .i.ni.
9:05-9:15 a.m.
1:20-1:55 p.m.
2:45-2:50 p.m.
3:05-3:20 p.m.
3 min
15 mln
4:10-4:25 p.m.
5:30 p.m.
8:45 a.m.
8:55-9:05 a.m.
10:20-10:25 a.m.
11:05-11:30 a.m.
11:45-12:05 p.m.
12:10-12:25 p.m.
12:30 p.m.
6:15 a.m.
6:20-6:35 a.m.
6:37-6:50 a.m.
6:50-7:10 a.m.
8:15-8:40 a.m.
12:55-1:30 p.m.
2:15-2:35 p.m.
2.5 mln
15 mln
3:55 p.m.
6:10 a.m.
6:20-6:25 a.m.
9:15-10:15 a.m.
10:45-11:15 a.m.
1:15-1:25 p.m.
3:05-3:07 p.m.
3:15-3:40 p.m.
N.R.
N.R.
4:55-5:30 p.m.
5:10 p.m.
Pl.int start-up.
Vibrating conveyor (C-2) receiving shredder 1 discharge plugged.
Vibrating conveyor (C-2) plugged.
Changed trailers.
Belt conveyor (C-1) shredders 1 to 2 plugged.
Belt conveyor (C-3) plugged.
Raw refuse In-feed conveyor (C-1) Jammed once.
Pneumatic conveyor high-pressure limit switch activated five times.
Belt ripped on magnetic belt separator. Shut off shredder 1.
Plant shutdown.
Plant start-up.
ADS vibrating feeder plugged.
Belt conveyor (C-3) shredders 1 to 2 jammed.
Sweep conveyor In Atlas bin broken.
Belt conveyor (C-3) plugged.
Belt conveyor (C-3) plugged.
Plant shutdown.
After plant shutdown, changed belt In magnetic belt separator. This work required balance
of the day. Also checked Installation of curtains In shredder.
Plant start-up.
Belt conveyor (C-3) shredder I to 2 plugged.
Belt conveyor (C-3) plugged.
Cut out remaining curtain In shredder 2 in-feed throat.
Changed trailers.
Vibrating conveyor (C-2) receiving discharge from Shredder 1 plugged.
Changed trailers.
Raw refuse In-feed conveyor (C-1) Jammed once.
Pneumatic conveyor high-pressure limit switch activated six times.
Plant shutdown.
Have started new maintenance shift of one man 3:00 p.m. to 11:00 p.m.
Plant start-up.
Vibrating conveyor (C-2) receiving shredder 1 discharge plugged.
Changed trailers.
ADS heavies belt conveyor (C-7) plugged. ADS reverse air trap plugged.
Hopper feeding belt conveyor (C-3) shredder 1 to 2 plugged.
Emergency stop on belt conveyor (C-3) tripped by pile up of refuse.
Changed trailers.
Raw refuse in-feed conveyor (C-1) jammed once. Time not recorded.
Pneumatic conveyor high-pressure limit switch activated once. Time not recorded.
ADS plugged. Motor overload relay nctivated.
Plant shutdown.
(continued)
-------
TABLE C-lc* (continued)
Day
(August 1976)
25
26
27
Day of
Week
Wednesday
Thursday
Friday
3.6
7.1
6,5
30
Monday
9.2
u>
o
31
Tuesday
11.1
Clock Time Description
2; 25 p.m. Plant start-up.
2:50-2:55 p.m. Broken shear pin en raw refuse tn-feed conveyor (C-l).
12 min Conveyor (C-l) jammed five times.
6:00 p.m. Plant shutdown,
9:25 a.m. Plant start-up.
9:25-9:45 a.m. Belt conveyor (C-6) to ADS jammed at tail pulley.
9:55-10:35 a.m. Flight broke loose in raw refuse In-feed conveyor (C-l).
2:20-2:25 p.m. Belt conveyor (C-6) jammed at tall pulley,
2 mln Conveyor (C-l) jammed once.
6:30 p.m. Plant shutdown,
6:30 a.m. Plant start-up.
8:55-9:00 a.m. Belt conveyor (C-6) to ADS plugged, In turn causing vibrating convevor (C-5) to pl«"g.
10:25-10:30 a.m. Broken shear p{n on raw refuse in-feed conveyor (C-l).
10:35-11:15 a.m. Broken bolt on conveyor (C-l).
11:15-11:50 a.m. Not enough refuse accumulated to process. Shutdown for lunch.
12:10-12:40 p.m. Broken bolt on conveyor (C-l).
1:00 p.m. Plant shutdown at request of power plant.
6:10 a.m. Plant start-up-
6:40-6:45 a.m. Hopper feeding belt conveyor (C-3) shredder 1 to 2 plugged.
7:40-7:45 a.m. Magnetic belt separator stopped.
7:55-8:00 a.m. Fe-metal bolt conveyor (C-12) Jammed by wire.
6:15-8:40 a.m. Changed trailers.
9:10*9:30 a.m. APS feeder plugged.
9:50-9:55 a.m. Belt conveyor (C-3) plugged.
10:35-10:40 a.m. Fe-metal belt conveyor (C-13) jammed.
10:45-11:50 a.m. Cleaned reverse air trap on ADS.
12:05-12:10 p.m. Magnetic belt separator stopped.
1:45-1:50 p.m. Raw refuse in-feed conveyor (C-l) stopped.
3:05 p.m. ADS feeder stopped,
3;20 p.m. Plant shutdown,
6:15 a.m. Plant start-up.
6:55-7:05 a.m. ,ADS motor overload relay activated.
11:50-12:05 p.m. Fe-metal conveyor (C-10) Jammed.
12:40-1:00 p.m. Changed trailers.
4:55-5:20 p.m. Hopper to belt conveyor (C-3) shredders 1 to 2 plugged.
5:20 p.m. Plant shutdown.
a/ Processing day-hours is time span from first plant start-up to last plant shutdown, which is the time period the plant must be fully staffed, Process-
Ing day-hours does not include maintenance and cleaning hours prior to plant start-up and after plant shutdown. Also actual hours spent shredding
refuse la less than processing day-hours due to various categories of downtime.
-------
TABLE C-ld. DAILY RECORD OF REFUSE PROCESSING PLANT ACTIVITY FOR THE MONTH OF SEPTEMBER 1976
Pay
(September 1976)
Day of
Week
Wednesday
Processing
Day-Hours!/
7:00 a.m.-7:30 p.m.
Description
No processing.
Changed all the hammers in the primary shredder. This required use of the front-end
loader which was out of service for 45 min due to a broken hydraulic line to the
bucket. At this point In time estimate hammer life for the total of all working
faces as follows:
Primary shredder - 20,000 Mg.
Secondary shredder - 12,000 Mg.
Thursday 10.3 6:15 a.m. Plant start-up.
6:20-7:15 a.m. Belt conveyor (C-6) to ADR tall pulley jammed and vibrating conveyor (C-5) under
Shredder 1 plugged as a result.
9:25-10:05 a.m. Changed trailers.
1:05-1:45 p.m. Shutdown to repair pneumatic conveying line elbow.
2:00-2:05 Magnetic belt separator stopped.
4:15-4:25 Vibrating conveyor (C-2) under shredder 1 plugged.
4:30 p.m. Plant shutdown.
Friday 12.4 6:10 a.m. plant start-up.
7:25-7:30 Fe-metal belt conveyor (C-10) plugged by bed springs and wire.
9:35-9:40 Raw refuse In-feed conveyor (C-l) stopped.
12:05-12:35 p.m. Changed trailers and cleaned out reverse air trap of the ADS blower.
4:45-5:00 Rotary feeder on ADS plugged.
6:35 p.m. Plant shutdown.
Monday 0 Holiday - Labor Day.
Tuesday 0 Plant not operated to allow power plant to empty surge bin.
Wednesday 4:40 p.m. Plant start-up.
Magnetic belt separator stopped four times because of high steel content of refuse for
a total of 26 min downtime. Raw refuse feed conveyor (C-l) stopped once for added down-
3 min time of 3 min.
7:35 p.m. Plant shutdown.
Thursday 12.8 5:00 a.m. Plant start-up.
7:35-7:50 Change trailers.
9:05-9:35 Tall pulley on raw refuse feed conveyor (C-l) broken.
9:50-12:00 Primary shredder (1) plugged by rolls of smooth wire.
N.R. Magnetic belt separator stopped three times, raw refuse feed conveyor (C-l) once, and the
pneumatic high-pressure limit switch three times. Times not recorded.
5:45 p.m. Plant shutdown.
(continued)
-------
TABLE C-ld. (continued)
Day
(September 1976)
10
Day of
Week
Friday
Process! ng
Day-Hours—
13.7
u>
13
14
15
Monday
Tuesday
Wednesday
9.2
3.5
10.9
16
Thursday
9.3
Clock Time Description
5:15 a.m. Plant start-up.
9:45-10:40 Front-end loader inoperable.
11:05-11:15 Feed hopper for belt conveyor (C-3) shredder I to 2 bridged.
12:15-12:30 Trailer changed.
3:45-4:05 ADS vibrating feeder plugged.
4:05-4:10 Front-end loader stopped.
5:15-5:50 Front-end loader stopped.
N.R. Pneumatic conveyor system high-pressure limit switch activated three times.
6:55 p.m. Plant shutdown.
7:20 a.m. Plant start-up.
2:10-3:10 Change trailers and clean motor of secondary shredder (2)
N.R. Magnetic belt separator stopped twice. Time not recorded.
4:30 p.m. Plant shutdown.
12:30 p.m. Plant start-up.
12:55-1:05 ADS rotary feeder breaker switch went off.
N.R. Pneumatic conveyor high-pressure limit switch activated twice. Time not recorded.
2:30-2:40 Air compressor stopped.
4:00 p.m. Plant shutdown.
5:05 a.m. Plant start-up.
7:15-7:45 Changed trailers in error, load 1 ton light.
8:15-8:40 Changed trailers.
9:15-9:25 Vibrating conveyor (C-2) under primary shredder plugged.
12:25-2:30 ADS heavies bucket elevator (F.-1) chain broke.
N.R. Magnetic belt separator stopped twice. Time not recorded.
4:00 p.m. Plant shutdown.
6:10 a.m. Plant start-up.
6:20-6:25 In-feed conveyor (C-l) jammed.
10:00-10:15 Change trailers.
11:40-12:00 Rotary feeder on ADS stopped because of thermal overload.
H.R. Magnetic separator stopped five times. Time not recorded.
3:30 p.m. Plant shutdown.
Time not recorded.
(continued)
-------
TABLE C-ld. (continued)
CO
10
Day Day of Processing
(September 1976) Week Day -Hours*/ Clock Time
17 Friday 7.8 6:20 a.m.
7:00-7:20
8:00-8:35
11:40-11:45
N.R.
N.R.
N.R.
2:30 p.m.
20 Monday 7.5 8:00 a.m.
8:15-8:20
9:50-9:55
1:25-2:15
N.R.
N.R.
N.R.
3:30 p.m.
21 Tuesday 8.0 N.R.
12 mln
9:05-9:20
20 min
N.R.
22 Wednesday 6.2 7:05 a.m.
8:30-8:40
9:25-9:40
10:05-10:15
11:10-11:40
12:10-12:15
12:50-1:00
N.R.
N.R.
1:15 p.m.
Description
Plant start-up.
Change trailers.
In-feed conveyor (C-l) lost some bolts.
Vibrating conveyor (C-2) under primary shredder plugged.
In-feed conveyor (C-l) stopped five times. Time not recorded.
Magnetic belt separator stopped once. Time not recorded.
Pneumatic conveyor high-pressure limit switch activated eight times. Time not recorded.
Plant shutdown.
Plant start-up.
Heavies conveyor under ADS (C-7) plugged.
Shear pin in in-feed conveyor (C-l) drive sheared.
Changed trailers. Excessive time due to split heater hose on semitractor repair.
Pneumatic conveyor high-pressure limit switch activated seven times. Time not recorded.
In-feed feed conveyor (C-l) stopped once. Time not recorded.
Magnetic belt separator stopped once. Time not recorded.
Plant shutdown.
Plant start-up. Time not recorded.
Pneumatic conveyor high-pressure limit switch activated three times (12 min). Time not
recorded.
Belt conveyor (C-6) to ADS jammed.
In-feed conveyor (C-l) stopped four times.
Plant shutdown. Time not recorded.
Plant start-up.
Feed hopper for belt conveyor (C-3) bridged.
Change trailer.
ADS heavies belt conveyor (C-7) plugged.
ADS return air duct plugged.
ADS heavies belt conveyor (C-7) plugged.
ADS heavies belt conveyor (C-7) plugged.
In-feed conveyor (C-l) stopped once. Time not recorded.
Pneumatic conveyor high-pressure limit switch activated three tltnes. Time not recorded.
Plant shutdown.
(continued)
-------
TABLE C-ld. (continued)
u>
-P-
Day Day of Processing
(September 19761 Week Day-Hours^' Clock Time
23 Thursday 7.8 7:00 a.m.
N.R.
2 mln
8:05-8:55
9:05-9: 10
10:10-10:30
11:45-12:00
1:55-2:00
2:45 p.m.
24 Friday 5.9 9:45 a.m.
N.R.
N.R.
N.R.
9:50-10:00
11:10-11:15
12:00-12:25
12:45-12:50
1:20-1:50
3:20-3:30
3:40 p.m.
27 Monday 7.8 6:TO a.m.
15 mln
N.R.
8:55-9:15
9:25-9:35
10:20-10:25
12:25-12:29
2:00 p.m.
28 Tuesday 4.4 7:05 a.m.
7:10-7:15
8:40-8:45
9:00-9:05
10:55-11:00
N.R.
N.R.
11:30 a.m.
Description
Plant start-up.
Pneumatic conveyor high-pressure limit switch activated twice. Time not recorded.
Stop to check operation of vibrating conveyor (C-2) under primary shredder.
Primary shredder (1) plugged.
ADS heavies bucket elevator (E-l) bridged at discharge point onto belt conveyor (C-14).
Change trailers.
ADS rotary feeder plugged.
ADS heavies belt conveyor (C-7) jammed.
Plant shutdown.
Plant start-up.
In-feed conveyor (C-l) stopped twice. Time not recorded.
Pneumatic conveyor high-pressure limit switch activated once. Time not recorded.
Magnetic belt separators stopped twice. Time not recorded.
Feed hopper for belt conveyor (C-3) bridged.
Conveyor belt (C-7) plugged.
Change trailers.
Conveyor belt (C-7) plugged.
ADS air return screen blocked.
In-feed conveyor (C-l) jammed.
Plant shutdown.
Plant start-up.
Pneumatic conveyor high-pressure limit switch activated four times. Time not recorded.
Magnetic belt separator stopped three times. Time not recorded.
Change trailers.
By-pass chute on secondary shredder inadvertently opened.
In-feed conveyor (C-l) jammed, activating breaker switch.
Pneumatic conveyor high-pressure limit switch activated.
Plant shutdown.
Plant start-up.
ADS rotary feeder breaker switch activated.
Vibrating conveyor (C-2) under primary shredder plugged.
In-feed conveyor (C-l) plugged.
In- feed conveyor (C-l) jammed.
In-feed conveyor (C-l) stopped. Time not recorded.
Pneumatic conveyor high-pressure limit switch activated twice. Time not recorded.
Plant shutdown.
-------
TABLE C-ld. (continued)
Day
(September 1976)
29
Day of
Week
Wednesday
Processing
Day-Hours8.'
1.8
Clock Time
7:10 a.m.
8:00-8:20
9:15-9:20
9:30-9:35
Description
Plant start-up.
Change trailers.
Conveyor belt C-7 plugged.
Conveyor butt C-7 plugged.
Plant shutdown. Link belt orator burned out.
30
Thursday
9.4 6:00 a.m. Plant start-up.
6:00-7:45 a.m. ADS drag conveyor bridged and row refuse In-feed conveyor (C-l) stop control accidentally hit
by front-end loader. By-passed local stop control to operate conveyor.
S:'i5-9:20 a.m. AHS surge bin bridged and belt conveyor (C-6) feeding surge bin jammed at head pulley.
12:30-12:50 Changed trailers.
2:15-2:20 Vibrating conveyor (C-2) under shredder 1 plugged due to light paper.
2:25-2:35 p.m. ADS surge bin plugged.
N.R. Pneumatic conveyor high-pressure limit switch activated five times. Time not recorded.
3:25 p.m. Plant shutdown.
00
Ul
a/ Processing day hours Is time span from first plant start-up to last plant shutdown, which Is the time period the plant must be fully staffed. Processing
day»hours does not Include maintenance and cleaning hours prior to plant start-up and after plant shutdown. Also actual hours spent shredding refuse Is
less than processing day-hours due to various categories of downtime.
-------
TABLE C-le. DAILY RECORD OF REFUSE PROCESSING PLANT ACTIVITY FOR THE MONTH OF OCTOBER 1976
Day
(October 1976)
Day of
Week
Friday
Process! ng
Day-HoursA'
9.2
Monday
8.3
OJ
Tuesday
8.3
Wednesday
3.7
Time not recorded.
Clock Time Description
7:00 a.m. Plant start-up.
8:25-8:35 a.m. ADS surge bin bridged.
9:50 a.m. Conveyor belt (C-7) receiving ADS heavies plugged.
9:55-10:20 a.m. Fe-mctal belt conveyor (C-12) jammed due to tin cans.
11:30-11:50 a.m. Changed trailers.
1:40-1:50 p.m. Conveyor belt (C-7) plugged.
2:50-3:10 p.m. Conveyor belt (C-7) plugged.
3:30-4:10 p.m. Conveyor belt (C-7) plugged.
N.R. In-feed conveyor (C-l) jammed once. Time not recorded.
N.R. Magnetic belt separator jammed once. Time not recorded.
N.R. Pneumatic conveyor system high-pressure limit switch activated once.
4:10 p.m. Plant shutdown.
6:10 a.m. Plant start-up.
6:20-6:40 a.m. Feed hopper for belt conveyor (C-3) shredder 1 to 2 bridged.
8:00-8:20 a.m. Changed trailers.
8:30-8:50 a.m. Vibrating conveyor (C-2) under shredder 1 plugged.
11:50-12:05 ADS heavies belt conveyor (C-7) plugged.
2:30 p.m. Plant shutdown.
7:10 a.m. Plant start-up.
8:15-8:30 a.m. ADS heavies belt conveyor (C-7) plugged.
9:40-10:00 a.m. ADS return air duct plugged.
1:00-2:00 p.m. Shutdown at request of power plant.
3:25 p.m. Plant shutdown.
Storage bin manufacturer Is changing storage bin control center so that speed can be
changed on storage bin sweep conveyor. Estimated time of completion Is 3 days. Process-
Ing plant will continue to operate and RDF will be placed in the storage bin even though
sweep conveyor is inoperative.
11:45 a.m. Plant start-up.
1:00-1:05 p.m. Vibrating conveyor (C-2) under shredder 1 plugged.
H.R. Raw refuse In-feed conveyor (C-l) jammed once. Time not recorded.
U.R. Pnrumatlc conveyor high-pressure limit switch activated once. Time not recorded.
3:25 p.m. Plant shutdown.
(continued)
-------
TABLE C-le» (continued)
i-o
Day Day of Processing
(October 1976) Week Day-HoursS/ Clock Time
7 Thursday 7.8 6:10 a.m.
10:30-10:40 a.m.
10:40-10:45
11:20-12:50 p.m.
1:10-1:30 p.m.
2:10-2:15 p.m.
N.R.
N.R.
N.R.
3:00 p.m.
8 Friday 11.7 7:05 a.m.
7:22-10:35 a.m.
4:00-4:25 p.m.
N.R.
6:45 p.m.
11 Monday 7.2 8:15 a.m.
11:45-12:15 p.m.
3:15-3:20 p.m.
30 min
5 min
3:25 p.m.
Description
Plant start-up.
ADS heavies belt conveyor (C-7) plugged.
Broken shear pin in raw refuse in- feed conveyor (C-l).
Changed trailers.
Belt conveyor (C-7) plugged.
In- feed conveyor (C-l) jammed.
Pneumatic conveyor high pressure limit switch activated twice. Time not recorded.
In-feed conveyor (C-l) stopped five times. Time not recorded.
Magnetic belt separator stopped once. Time not recorded.
Plant shutdown.
Plant start-up.
Motor burned out on ADS vibrating feeder.
Changed trailers.
Raw refuse in feed conveyor (C-l) stopped three times. Time not recorded.
Plant shutdown-
Plant start-up.
Changed trailers*
Removed tree stump from raw refuse in-feed conveyor (C-l).
Pneumatic conveyor high-pressure limit switch activated 12 times.
Raw refuse in-feed conveyor (C-l) stopped twice.
Plant shutdown.
mf Processing day.hours is time span from first plant start-up to last plant shutdown, which is the time period the plant must be fully staffed.
Processing day-hours does not include maintenance and cleaning, hours prior to plant start-up and after plant shutdown. Also actual hours
shredding refuse is less than processing day-hours due to various categories of downtime.
-------
TABLE C-le. (continued)
Day
(October 1976)
12
Day of
week
Tuesday
Processing
day-hoursJL'
8.3
13
Wednesday
7.3
OJ
oo
14
Thursday
4.9
15
Friday
5.3
Clock t ime
7:10 a.m.
B:05-8:30
9:50-10:35
11:05-11:10
3:25 p.m.
7:05 a.m.
7:45-8:15
9:50-10:00
12:45-1:30
1:40-1:45
N.R.
N.R.
2:25 p.m.
10:30 a.m.
2:30-2:40
K.R.
3:25 p.m.
7:05
7:45-8:10
11:20-12:00 p.m.
Description
Plant start-up.
Clean ADS air trap.
Changed trailers.
Feed hopper for belt conveyor (C-3)shreddcr 1 to 2 bridged.
Plant shut down.
Note: Combustion power maintenance person has worked for 3 days adjusting
speed switches on conveyors. Also Installed automatic shut-off switch
on magnetic belt separator to prevent belt damage.
Plant start-up.
Changed trailers.
Vibrating conveyor (C-2) under shredder 1 plugged.
ADS airlock screen blocked.
Removed heavy steel from ferrous metal belt conveyor (C-12).
Pneumatic conveyor system higji pressure limit switch activated once. Time not
recorded.
Raw refuse in-feed conveyor (C-l) jammed once. Time not recorded.
Plant shut down.
Note: Start-up delayed at request of power plant. Cause attributed to silica
slag buildup directly above fire ports in spreader-stoker boiler No. 5,
reducing air intake and improper air:fuel mixture.
Plant start-up.
Ferrous metal belt conveyor (C-ll) came off tracks.
Magnetic belt separator stopped once. Time not recorded.
Plant shut.down.
Plant start-up.
Changed trailers.
ADS heavies belt conveyor (C-7) plugged.
(continued)
-------
TABLE C-le. (continued)
Day
(October 1976)
D«y of
week
Processing
day-hour s8-
18
Monday
8.3
I-1
U>
vo
19
Tuesday
8.4
20
Wednesday
7.6
Clock time
12:00-12:20
12:20
N.R.
N.R.
N.R.
12:20 p.m.
6:10 a.m.
7:05-7:20
11:00-11:25
11:50-12:05
N.R.
N.R.
2:30 p.m.
7:05 a.m.
9:00-9:10
9:10-9:40
10:50-11:10
11:35-1:45
N.R.
N.R.
N.R.
3:30 p.m.
7:00 a.m.
8:25-8:30
9:10-9:25
N.R.
N.R.
Description
Cleaned out ADS r.-verse air trap.
Cyclone bridged when system restart attempted.
Raw refuse in-feed conveyor (C-l) jammed once. Time not recorded.
Magnetic belt separator stopped three times. Time not recorded.
Pneumatic conveyor system high pressure limit switch activated once.
recorded.
Plant shut down.
Time not
Plant start-up.
Changed trailers.
Changed trailers.
Cleaned out ADS reverse air trap.
Magnetic belt separator stopped twice. Time not recorded.
Pneumatic conveyor system high pressure limit switch activated 14 tiroes.
not recorded.
Plant shut down.
Times
Plant start-up.
ADS feeder motor overload relay activated.
Changed trailers.
Cleaned out ADS reverse air trap.
Screw conveyor feeding pneumatic conveying system plugged.
In-feed conveyor (C-l) plugged twice. Time not recorded.
Magnetic belt separator stopped twice. Time not recorded.
Pneumatic conveyor system high pressure limit switch activated four times. Time
not recorded.
Plant shut down.
Plant start-up.
Feed hopper for belt conveyor (C-3) shredder 1 to 2 bridged.
Changed trailers.
In-feed conveyor (C-l) stopped once. Time not recorded.
Pneumatic conveyor system high pressure limit switch activated eight times.
Time not recorded.
(continued)
-------
TABLE C-le. (continued)
Day
(October 1976)
Day of Processing
week day-hours—
20 (Concluded)
21 Thursday 5.5
22
Friday
25
Monday
26
27
Tuesday
7.7
8.3
5.0
Wednesday 5.3
Clock time Description
2:35 p.m. Plant shut down. Combustion power not running.
7:0') a.m. Plant start-up.
9:00-9:15 Ferrous metal belt conveyor (C-12) jammed.
12:35 p.m. Plant shut down. Ivow on refuse.
7:30 a.m. Plant start-up.
8:30-8:35 Hopppr feeding belt conveyor (C-3) shredders 1 to 2 bridged.
1:15-1:35 Changed trailers.
2:05-2:25 Vortical section of ADS drag conveyor plugged.
3:00 Primary shredder jammed with telephone wire.
3:10 p.m. Plant shut down.
7:05 a.m. Plant start-up.
10:50-11:15 Changed trailers.
N.P. In-fced conveyor (C-l) jammed five times. Time not recorded.
N.R. Magnetic belt separator stopped four times. Time not recorded.
N.R. Pneumatic conveyor high pressure limit switch activated 10 times. Time not
recorded.
3:25 Changed trailers.
3:25 p.m. Plant shut down.
10:00 a.m. Plant start-up.
11:10-11:20 Vertical section of ADS drag conveyor plugged.
N.R. Magnetic belt separator stopped three times. Time not recorded.
N.R. Pneumatic conveyor high pressure limit switch activated three tiroes.
3:00 p.m. Plant shut down.
10:10 a.m. Plant start-up.
11:45-12:25 ADS heavies belt conveyor (C-7) plugged. Cleane
-------
TABLE G-le. (continued)
Day
(October 1976)
27 (Concluded)
Day of Processing
week day-hours8/
Clock time
2:55-3:20
3:20
3:25
Description
Rotary feeder on ADS plugged.
Screw conveyor feeding pneumatic conveying system plugged.
Plant shut down.
28
Thursday
10.9
29
Friday
1.3
7:10 a.m.
7:35-9:A5
9:45-9:50
11:05-11:10
11:25-12:45
12:45-1:05
2:30-2:35
N.R.
6:05 p.m.
7:00 a.m.
N.R.
8:20 a.m.
Plant start-up.
Screw conveyor feeding pneumatic conveying system plugged.
ADS heavies belt conveyor (C-7) plugged.
Ferrous metal belt conveyor (C-12) jammed.
Screw conveyor feeding pneumatic conveying system plugged.
Changed trailers.
Vibrating conveyor (C-2) under primary shredder plugged.
Combustion power did not run.
Plant shut down.
Plant start-up.
Magnetic belt separator stopped once.
Plant shut down.
Time not recorded.
Processing day-hours is time span from first plant start-up to last plant shutdown, which is the time period the plant must be fully staffed. Process-
ing day-hours does not include maintenance and cleaning hours prior to plant start-up and after plant shutdown. Also actual hours spent shredding
refuse is less than processing day-hours due to various categories of downtime.
-------
TABLE G-lf. DAILY RECORD OF REFUSE PROCESSING PLANT ACTIVITY FOR THE MONTH OF NOVEMBER 1976
Day
(November
1976)
Day of
week
Monday
Processing
day-hours—'
8.3
Tuesday
10.0
Wednesday
6.3
Clock time
8:25 a.m.
10:35-11:20
1:35-2:20
4:20-4:40
N.R.
N.R.
N.R.
4:45 p.m.
6:00 a.m.
6:15-6:20
9:05-9:25
2:25-2:45
N.R.
N.R.
N.R.
4:00 p.m.
7:00 a.m.
10:50-11:00
11:20-11:50
12:25-1:00
N.R.
N.R.
N.R.
1:20
1:20 p.m.
Description
Plant start-up.
ADS return air duct plugged.
Changed trailer.
Belt conveyor (C-3) stopped to replace broken drive belt.
In-feed conveyor (C-l) jammed once. Time not recorded.
Magnetic belt separator stopped six times. Time not recorded.
Pneumatic conveyor high pressure limit switch activated 20 times.
recorded.
Plant shut down.
Time not
Plant start-up.
Hopper feeding belt conveyor (C-3) between shredders 1 and 2 bridged.«
Changed trailers.
Changed trailers.
In-feed conveyor (C-l) stopped four times. Time not recorded.
Magnetic belt separator stopped once. Time not recorded.
Pneumatic conveyor high pressure limit switch activated six times. Time not
recorded.
Plant shut down.
Plant start-up.
ADS heavies belt conveyor (C-7) plugged.
Changed trailers.
Vibrating conveyor (C-2) under shredder 1 jammed.
In-feed conveyor (C-l) stopped eight times. Time not recorded.
Magnetic belt separator stopped twice. Time not recorded.
Pneumatic conveyor high pressure limit switch activated once. Time not recorded.
Shredder I jammed with a log.
Plant shut down.
(continued)
-------
TABLE C-lf. (continued)
Day
(November 1976)
Day of Processing
week day-hours^'
Thursday
7.3
Friday
8.6
-P-
UJ
Saturday
Clock time Description
7:05 a.m. Plant sta'rt-up.
9:55-10:15 Replace drive belts on (C-3) conveyor.
11:05-11:25 Changed trailers.
11:50-12:15 Cleaned ADS return air trap.
N.R. In-feed conveyor (C-l) plugged seven times. Time not recorded.
N.R. Magnetic belt separator stopped five times. Time nol recorded.
N.R. Pneumatic conveyor system high pressure limit switch activated four times. Time
not recorded.
2:20 p.m. Plant shut down.
7:05 Plant start-up.
8:00-8:15 Vibrating conveyor (C-2) under shredder 1 plugged.
9:45-10:00 Belt conveyor (C-3) threw belt, replaced.
10:40-10:55 Changed trailers.
N.R. In-feed conveyor (C-l) jammed seven times. Time not recorded.
N.R. Magnetic belt separator stopped three times. Time not recorded.
N.R. Pneumatic conveying system high pressure limit switch activated five times.
Time not recorded.
Fire discovered at about 4:00 a.m. in the plant processing area. Firemen broke
through skylight and extinguished fire by 6:00 a.m. Considerable smoke damage
In office areas; one TV camera destroyed. Electrical wiring melted In many
places. Conveyor C-6 melted and hydraulic system of shredder 2 melted. Con-
trol room windows broken, C-6 hopper Inner liner burned, C-6 drive motor burned/
melted, In-feed hopper from C-5 to C-6 warped beyond repair. Wall-hung vacuum
line destroyed, all insulation on water pipes above C-6 conveyor burned off,
two telephones melted, and all outside air controls burned out. Several light
fixtures burned, and styrofoam Insulation burned.
(continued)
-------
TABLE C-lf. (continued)
Day
(November 1976)
8-19
22
Day of
week
2 weeks
Monday
Processing
day-hours—
4.0
4.0
23
Tuesday
1.8
24
Wednesday
8.3
Clock time
6:00 p.m.
8:10-8:20
9:50-9:55
N.R.
N.R.
N.R.
10:05 p.m.
12 Noon
12:50-1:05
1:50
N.R.
N.R.
1:50 p.m.
7:00 a.m.
10:00-10:20
1:40-1:55
N.R.
N.R.
N.R.
3:20 p.m.
Description
Plant not operational because of fire damage and repair efforts. Plant personnel
engaged in cleaning up operating areas. Total operating time of approximately
4 hours involved in testing equipment and repairs prior to resuming full-scale
operations.
Plant start-up for test run.
Feed hopper for belt conveyor (C-3) shredder 1 to 2 bridged.
In-feed conveyor (C-l) shear pin broken.
In-feed conveyor (C-l) jammed four times. Time not recorded.
Magnetic belt separator stopped seven times. Time not recorded.
Pneumatic conveying system high pressure limit switch activated once. Time
not recorded.
Plant shut down.
Plant start-up.
Cleaned ADS air return trap.
ADS drag conveyor lost several flights.
In-feed conveyor (C-l) jammed twice. Time not recorded.
Magnetic belt separator stopped once. Time not recorded.
Plant shut down.
Plant start-up.
Changed trailer.
ADS feeder plugged.
In-feed conveyor (C-l) jammed eight times. Time not recorded.
Magnetic belt separator stopped six times. Time not recorded.
Pneumatic conveying system high pressure limit switch activated four times.
Time not recorded.
Plant shut down.
(continued)
-------
TABLE C-lf. (continued)
Ln
Day Day of Processing
(November) week day-hours— Clock time
25 Thursday -0-
26 Friday 7.3 8:05 a.m.
9t20-9:35
9:50-9:55
10:45-11:15
2:05-2:15
N.R.
N.R.
N.R.
3:20 p.m.
29 Monday 8.2 8:10 a.m.
9:30
11:05
11:55-12:05
1:40-1:50
N.R.
N.R.
N.R.
4:20 p.m.
30 Tuesday 9.3 7:10 a.m.
8:05-8:10
8:15-8:45
10:20-10:30
10:40-11:05
11:40-1:05
1:10-1:25
2:50-3:05
N.R.
N.R.
N.R.
4:25 p.m.
Description
Thanksgiving holiday.
Plant start-up.
Belt conveyor (C-6) to ADS jammed.
In-feed conveyor (C-l) jammed, activating breaker switch.
Clean ADS return air trap. Ferrous metal belt conveyor (C-13) Jammed.
Changed trailer.
In-feed conveyor (C-l) Jammed 11 times. Times not recorded.
Magnetic belt separator stopped 16 times. Time not recorded.
Pneumatic conveying system high pressure limit switch activated four times.
Times not recorded.
Plant shut down.
Plant start-up.
Stopped operations, no reason provided.
Operations restarted.
Belt conveyor (C-6) to ADS Jammed.
Belt conveyor (C-6) to ADS bridged.
In-feed belt conveyor (C-l) plugged once. Time not recorded.
Magnetic belt separator stopped 17 times. Time not recorded.
Pneumatic conveying system high pressure limit switch activated five times.
Times not recorded.
Plant shut down.
Plant start-up.
Latch on hopper feeding belt conveyor (C-3) broke.
Vibrating conveyor (C-2) plugged.
In-feed conveyor (C-l) jammed activating breaker switch.
In-feed conveyor (C-l) broken bolt repair.
ADS heavies belt conveyor (C-7) jammed.
Vertical section of ADS drag conveyor plugged.
Changed trailers.
In-feed conveyor (C-l) plugged eight times. Times not recorded.
Magnetic belt separator stopped once. Time not recorded.
Pneumatic conveying system high pressure limit switch activated three times.
Times not recorded.
Plant shut down.
t shutdown, which is the time period the plant must he fully staffed. Process-
ITIR day-hours does not include maintenance and cleaning hours prior to plant start-up and after plant shutdown. Also actual hours spent shredding
refuse la less than processing day-hours due to various categories of downtime.
-------
TABLE C-lg. DAILY RECORD OF REFUSE PROCESSING PLANT ACTIVITY FOR THE MONTH OF DECEMBER 1976
Day
(December 1976)
Day of Processing
vcck day -hour s—'
Wednesday
9.3
Thursday
8.6
Friday
8.2
Clock time
7:05 a.m.
7:30-7:40
8:30-8:45
10:30-10:35
12:25-12:30
1:00-1:55
2:30-2:50
2:50-3:00
N.B.
N.R.
N.R.
4:25 p.m.
6:00 a.m.
6:45-6:50
8:10-8:20
9:25-9:40
N.R.
N.R.
N.R.
2:35 p.m.
7:05 a.m.
7:10-7:20
8:00-8:15
8:40-8:45
12:05-12:50
1:05-1:10
N.R.
N.R.
3:15 p.m.
Description
Plant start-up.
Vibrating conveyor (C-2) plugged.
Adjusted magnetic belt separator raised one link.
In-feed conveyor (C-l) activated breaker switch.
In-feed conveyor (C-l) broken shear pin.
Hydraulic hose on front end loader split.
Changed trailers.
Repaired leaking hydraulic hose on front-end loader.
In-feed conveyor (C-l) plugged 21 times. Times not recorded.
Magnetic belt separator stopped 16 times. Times not recorded.
Pneumatic conveying system high pressure limit switch activated six times.
Times not recorded.
Plant shut down.
Plant start-up.
Door on hopper feeding (C-3) belt conveyor opened.
Vibrating conveyor (C-2) plugged.
Changed trailers.
In-feed conveyor (C-l) stopped 11 times. Time not recorded.
Magnetic belt separator stopped nine times. Time not recorded.
Pneumatic conveying system high pressure limit switch activated 10 times.
Time not recorded.
Plant shut down.
Plant start-up.
Vibrating conveyor (C-2) motor would not start due to extremely cold temperatures.
Stopped to clear primary shredder.
Stopped to clear jammed primary shredder.
Changed trailers.
ADS heavies belt conveyor (C-7) Jammed.
In-feed conveyor (C-l) plugged nine times. Time not recorded.
Magnetic belt separator stopped twice. Time not recorded.
Plant shut down.
(continued)
-------
TABLE C-lg. (continued)
Day
(December)
Day of
week
Monday
Processing
day-hours8-'
7.5
Tuesday
11.6
Clock time Description
6:00 a.m. Plant start-up.
8:25-8:30 Vibrating conveyor (C-5) jammed activating breaker switch.
8:55-9:25 Changed trailers.
9:30-9:40 Vibrating conveyor (C-5) jammed activating breaker switch.
11:10-11:20 Pneumatic conveyor high pressure limit switch activated.
12:05-12:15 ADS drag conveyor plugged In vertical section.
12:50-1:30 PSI blower switch activated.
N.R. In-feed conveyor (C-l) jammed 10 times. Times not recorded.
N.R. Pneumatic conveyor high pressure limit switch activated seven times. Times
not recorded.
1:30 p.m. Plant shut down.
Note: Aluminum metal separator Inoperable since November fire. Water pipes
are frozen, needs a few electrical repairs. Hot water reclrculatlng
system In pipes being considered.
7:05 a.m. Plant start-up.
7:20-7:30 Vibrating conveyor (C-2) activated breaker switch.
7:30-7:55 Front-end loader stopped running.
11:10-11:30 Changed trailer.
12:25-12:30 Vibrating conveyor (C-5) activated breaker switch.
12:50-3:05 PSI blower Inoperable, pipeline plugged at bin wear-back.
N.R. In-feed conveyor (C-l) plugged nine times. Time not recorded.
N.R. Magnetic belt separator stopped twice. Time not recorded.
N.R. Pneumatic conveyor system high pressure limit switch activated nine times. Times
not recorded.
6:40 p.m. Plant shut down.
Note: Temperature outside -12T today.
(continued)
-------
TABLE C-lg. (continued)
Day
(December 1976)
Day of
Week
Wednesday
Processing
day-hours0/
8.5
Thursday
8.4
00
10
Friday
9.4
Clock time Description
7:00-11:00 a.m. Hammers In shredders 1 and 2 replaced.
12 Noon Plant start-up.
1:30-1:50 Changed trailers.
3:15-3:20 Vibrating conveyor (C-5) activated breader switch.
N.R. In-feed conveyor (C-l) plugged once. Time not recorded.
N-R. Pneumatic conveying system high pressure limit switch activated once. Time
not recorded.
3:30 p.m. Plant shut down.
Outside temperature up to +38°F today. All fire and water lines thawed. Pipes
began falling down and water poured onto floor. Plant design specifications
did not include insulated pipes so most have been frozen in past few days.
7:05 a.m. Plant start-up.
7-10-7:30 Belt conveyor (C-3) would not start and ADS heavies belt conveyor (C-7) plugged.
11:45-11:50 Vibrating conveyor (C-5) stopped.
12:15-12:35 Changed trailers.
12:45-12:50 ADS feeder jammed.
N-R- In-feed conveyor (C-l) jammed five times. Times not recorded.
N_R- Magnetic belt separator stopped once. Time not recorded.
N]R] Pneumatic conveying system high pressure limit switch activated twice. Time
not recorded.
3:30 p.m. Plant shut down.
7:05 a.m. Plant start-up.
8-30-11:55 Shut down plant to thaw frozen water pipe.
2:00-2:25 Change trailer.
N^R. In-feed conveyor (C-l) jammed once. Time not recorded.
N'R Magnetic belt separator stopped once. Time not recorded.
N^R| Pneumatic conveying system high pressure limit switch activated twice. Time
not recorded.
4:30 p.m. Plant shut down.
(continued)
-------
TABLE G-lg. (continued)
Day
(December 1976)
13
Day of
week
Monday
Processing
day-hours—
8.3
14
Tuesday
8.3
15
Wednesday 3.2
16
Thursday 8.3
Clock time
6:50 a.m.
7:25-9:05
9:55-10:10
12:35-12:55
2:30-3:00
N.R.
N.R.
3:10 p.m.
7:00 a.m.
7:20-7:25
9:10-9:15
9:20-9:30
10:25-10:45
2:45-2:53
3:10-3:20
N.R.
N.R.
N.R.
3:20 p.m.
10:10 a.m.
11:10-11:30
1:20
N.R.
N.R.
1:20 p.m.
7:10 a.m.
N.R.
Description
Plant start-up.
Vertical section of pneumatic conveying pipe inside plant from cyclone to
ADS screw feeder plugged.
Fe-metal belt conveyor (C-10) plugged.
Changed trailer.
ADS return air plugged.
In-feed conveyor (C-l) jammed four times. Time not rer'-rded.
Magnetic belt separator stopped twice. Time not recorded.
Plant shut down.
Plant start-up.
Hopper feeding belt conveyor (C-3) plugged with wire.
ADS heavies bucket elevator (E-l) plugged.
ADS return air cleaned.
Changed trailer.
Heavier conveyor (C-7) under ADS jammed.
Front-end loader stopped. Wire entangled around driveshaft.
In-feed conveyor (C-l) plugged five times. Time not recorded.
Magnetic belt separator stopped once. Time not recorded.
Pneumatic conveying system high pressure limit switch activated seven times.
Times not recorded.
Plant shut down.
Plant start-up.
Changed trailer.
Bearing out on oscillating link belt conveyor
In-feed conveyor (C-l) jammed twice. Time not recorded.
Pneumatic conveying system high pressure limit switch activated three times.
Time not recorded.
Plant shut down.
Plant start-up.
Front-end loader brakes Inoperable, one-half day for repair.
loader.
Used Hough
(continued)
-------
TABLE C-lgt (continued)
Day
(December 1976)
16 (Continued)
Day of
week
Processing
day-hours^
17
Friday
9.3
Ui
O
20
Monday
16.0
Clock time Description
9:35-9:50 Cleaned ADS air return.
11:00-11:15 Changed trailer.
N.R. Magnetic belt separator stopped once. Time not recorded.
N.R. Pneumatic conveying system high pressure limit switch activated seven times.
Times not recorded.
3:30 p.m. Plant shut down.
7:10 a.m. Plant start—up.
7:40-8:35 Heavies conveyor (C-7) under ADS jammed; cyclone plugged.
9:00-10:35 Cyclone plugged, adjusted rotary feeder blades.
10:45-11:00 Changed trailers.
12:35-12:40 Fe-metal belt conveyor (C-10) jammed with wire.
1:10-3:00 Vertical section of flight conveyor plugged and motor on vibrating screen
broke loose from mounts.
N.R. Pneumatic conveying system high pressure limit switch activated three times.
Times not recorded.
N.R. Baled corrugated boxboard in afternoon.
4:30 p.m. Plant shut down.
6:00 a.m. Plant start-up.
7:10-7:40 Changed trailer.
8:40-9:00 ADS feeder plugged and surge bin bridged.
10:05-11:00 Oscillating conveyor stopped, adjusted setting.
11:35-2:10 Repair motor wiring.
2:40-3:10 Repair controls on air compressor for instrument air.
4:25-4:30 In-feed conveyor (C-l) jammed activating breaker switch.
4:40-4:50 ADS surge bin bridged.
5:05-5:10 In-feed conveyor (C-l) jammed activating breaker switch.
5:20-6:05 Changed trailers.
6:15-6:40 ADS surge bin bridged.
10:00 p.m. Plant shut down.
(continued)
-------
TABLE C-lg. (continued)
Day
Day of Processing
(December 1976) week day-hours—'
I/
21
Tuesday
9.3
22
h-1
-------
TABLE G-lg. (continued)
Day
(December 1976)
27
Day of
week
Monday
Processing
day-hours—'
8.1
28
Ui
to
29
Tuesday
Wednesday
8.1
6.3
30
Thursday 6.0
Clock time
7:00 a.m.
7:45-10:10
10:50-11:40
12:15-12:20
1:25-1:35
2:10-2:30
3:05
N.R.
N.R.
3:05 p.m.
7:15 a.m.
9:30-10:00
N.R.
N.R.
3:10 p.m.
10:15 a.m.
11:05-11:35
2:05-2:10
3:15-3:35
N.R.
N.R.
4:30 p.m.
10:20 a.m.
11:05-11:40
2:40-3:25
N.R.
4:25 p.m.
Description
Plant start-up.
Vibrating screen motor broken from base. Rewelded.
Heavies conveyor (C-7) jammed.
Heavies conveyor (C-7) jammed.
Heavies conveyor (C-7) jammed.
Cleaned ADS return air screen.
Fire In primary shredder. Plant shut down and fire exlinglshed by 3:30 p.m.
Shredder cleaned out.
In-feed conveyor (C-l) plugged twice. Time not recorded.
Pneumatic conveying system high pressure limit switch activated once. Time
not recorded.
Plant shut down.
Plant start-up.
Changed trailer.
In-feed conveyor (C-l) jammed twice. Time not recorded.
Magnetic separator stopped once. Time not recorded.
Plant shut down.
Plant start-up.
Change trailer.
Vibrating conveyor (C-5) activated breaker switch.
Cleaned ADS return air screen.
In-feed conveyor (C-l) stopped seven times. Times not recorded.
pneumatic conveying system high pressure limit switch activated once.
not recorded.
plant shut down.
Time
Plant start-up.
Changed trailer.
Heavies conveyor (C-7) jammed and cyclone bridged.
In-feed conveyor (C-l) jammed six times. Times not recorded.
Plant shut down.
(continued)
-------
TABLE C-lg. (continued)
Day Day of Processing
(December 1976) veek day-hours*' Clock time
31 Friday 6.0 10:40 a.m.
12:30-12:45
N.R.
4:45 p.m.
Description
Plant start-up.
Changed trailer.
In-feed conveyor (C-l) stopped six times. Time not recorded.
Plant shut down. Ho refuse to process.
Ul
u>
al Processing day-hours Is time span from first plant start-up to last plant shut down, which Is the time period the plant must be fully staffed.
Processing day-hours does not include maintenance and cleaning hours prior to plant start up and after plant shutdown. Also actual hours
shredding refuse Is less than processing day-hours due to various categories of downtime.
-------
TABLE C-2. RAW REFUSE DELIVERED BY PRIVATE INDIVIDUALS
(Private automobiles and pickup trucks)
Day
fHummmuAim
(June 1976)
9
10
11
12
14
15
16
17
18
23
24
25
29
(July 1976)
1
2
3
6
7
8
9
10
12
13
14
15
16
17
19
20
21
22
23
24
Day of
Week
Wednesday
Thursday
Friday
Saturday
Monday
Tuesday
Wednesday
Thursday
Friday
Wednesday
Thursday
Friday
Tuesday
Thursday
Friday
Saturday
Tuesday
Wednesday
Thursday
Friday
Saturday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Total
Refuse
Delivered
(kg)
3,852
3,978
4,563
11,799
3,973
9,317
8,391
5,062
5,851
1,860
2,440
3,057
3,438
3,565
7,530
4,618
10,414
3,810
3,193
4,944
11,703
6,858
5,770
3,946
4,354
6,096
12,619
15,966
12,147
6,323
5,153
5,924
11,331
Number
of Private
Vehicles
72
60
68
126
74
84
63
55
82
69
74
66
53
70
115
70
115
70
41
65
139
63
53
43
54
62
119
53
52
44
46
53
180
Average
Weight
(kg/vehicle)
53.5
66.3
67.1
93.6
53.7
110.9
133.2
92.0
71.4
27.0
33.0
46.3
64.9
50.9
65.5
66.0
90.6
54.4
77.9
76.1
84.2
108.9
108.9
91.8
80.6
98.3
106.0
301.3
233.6
143.7
112.0
111.8
63.0
(continued)
154
-------
TABLE C-2. (continued)
Day
Day of
Week
Total
Refuse
Delivered
(kg)
Number
of Private
Vehicles
Average
Weight
(kg/vehicle)
(July 1976) (Concluded)
26
27
28
29
30
31
(August
11
12
13
14
16
17
21
25
26
27
28
30
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
1976)
Wednesday
Thursday
Friday
Saturday
Monday
Tuesday
Saturday
Wednesday
Thursday
Friday
Saturday
Monday
10,687
4,799
7,003
17,382
6,840
8,020
5,815
6,677
6,051
9,344
8,355
4,745
12,628
4,835
7,824
6,822
13,535
10,287
70
64
48
72
75
139
47
53
75
151
80
52
139
44
51
76
183
82
152.7
75.0
145.9
241.4
91.2
57.7
123.7
126.0
80.7
61.9
104.4
91.3
90.8
109.9
153.4
89.8
74.0
125.5
Total
365,494
3,954
Standard deviation
Confidence interval at 95% confidence level
Number of days in survey =51
92.
50.66
+ 14.2
a/ Total refuse delivered divided by total vehicles.
155
-------
TABLE C-3. PROCESSING PLANT WORK STATION JOB DESCRIPTION
Title
No.
Employees
Full-Time Bnplovees
(Regular Shift 8:00-4:30;
Maintenance Shift 2:00-10:30)
Plant Superintendent
(Professional, managerial)
Chief Operator
End Loader Operator
Maintenance Man II
Work Station and Job Description
Work Station; Office and Control Room
Reeutar Shift Job Description; Plans, assigns, and super-
vises -11 plant operations and operations at landfill-
Recommends and directs changes in plant operation and
methods. Assists in scheduled visits and in safety of
visitors and employees. Inspects and supervises mainten-
ance and major overhaul of equipment. Maintains records
and prepares reports on plant operation, mass flow income,
and expense records, etc. Schedules work shifts. Responds
to emergency calls regarding plant equipment breakdowns
and power outages. Maintains good public relations. (See
City of Ames data for education and skill requirements and
for experience needed.
Work Station; Main Station - Control Panel located in control
room. Other areas in plant as needed for maintenance or
supervision.
Regular Shift Duties;
1. Operates plant machinery
2. Supervises all operating and maintenance employees
3. Supervises cleaning, maintenance, and repair of build-
ing and equipment
4. Trains new employees
5t Reviews plant records, meters
6. Keeps records and prepares daily and monthly reports on
plant operations
7. Assists in planning and designing changes in plant and
equipment
8. Schedules work shifts of operating personnel and assists
in selecting new operations and maintenance personnel.
Work Station; Front End Loader located on tipping room floor -
Landfill.
Regular Shift Duties a
I. Pushes solid waste up onto pile. Pushes solid waste onto
2-pan conveyor (C-l).
2. Visually inspects solid waste for hazardous items
3. Assists in directing traffic through the plant
4. Covers material in landfill - demolition material once
per week, 3M material once per day. Requires 2 hr in
morning (8-10 a.m.)
Man No. li Electrical Maintenance
Work Station; Process Plant
Maintenance Shift; 2:00-10:30 p.m.
Duties: General maintenance on electric motors, wiring, and
related equipment as required.
Man Wo. 2; Mechanical Maintenance
Work Station; Process Plant
Maintenance Shift: 2:00-10;30 p.m.
Duties;
It Performs mechanical maintenance on process equipment
and conveyors as required
2. Determines ways of minimizing maintenance workload
through planned replacement of parts, adjustment of
operating speeds, etc.
Man No. 3;
Welding
Station; Process Plant
2:00-10:30 p.m.
(continued)
Work
Maintenance Shift;
Duties;
I. Welds hammers
2. Assists when other Maintenance Men Il's are unable to
perform a job because of other work being done in paint.
156
-------
TABLE C-3. (continued)
Title
Maintenance Man I
No.
Bnolovees
Work Station and Job Description
Man No. I: General Maintenance
Itork Station;
1. Tipping Room Floor
2. Paper Baler Room
3. Log Chipper
Regular Shift Duties;
1. Assists customers on tipping room floor
2. Operates paper baler
3. Keeps floor clean (operates sweeper)
4. Operates log chipper
5. Assists in looking for hazardous waste material
6. Minor maintenance work (misc.)
Man No. 2; General Maintenance
Work Station; Tipping Room Floor
Maintenance Shift; 2:00-10:30 p.m
Duties;
!• Greasing equipment
2. Assist Maintenance Men II*s as needed
Truck Driver
Work Station; Truck or Tipping Room Floor
Regular Shift Duties;
1. Haul material to landfill
2. Change ferrous trailers (30 ft, 4 wheel)
3. Assist in cleaning heavy metal storage area of
tipping floor
4. Occasional maintenance (as a Maintenance Man I)
Total Full-Time Bnolovees in Plant; Supervisory: 1
, Full-time hourly: 8
Total full-time: 9
Part-Time Bnplovees
Tour Guide
Work Station: Office and Control Room, also Conference Room
Regular Shift; (Half time)
Duties:
!• Conducts tour of plant
2. Explains operation of plant to visitors, shows
film cassette description of plant history and function
Janitor-Office
Work Station;
1. Office and Control Room
2. Occasionally tipping floor
Regular Shift; (half time, 8-12 a.m.)
Duties;
1. Clean up office and control room
2. Assist if needed on tipping floor to direct customers,
etc.
Janitor-Plant
Work Station; Process Plant
Shift; (Half time, 4-8 p.m.)
Duties: Clean up processing area of plant.
Total Part-Time Bnplovees in Plant; 5
157
-------
TABLE C-4a.
DAILY PROCESSING HOURS—REFUSE PROCESSING PLANT
FOR THE MONTH OF JUNE 1976
Day
June 1976
1
2
3"
4
7
8
9
10
11
14
15
16
17
18
19
21
22
23
24
25
28
29
30
Total
Average
Day of
Week
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Raw
Refuse
In-Feed
(hr)£/
6.4
6.9
8.1
8.6
3.6
4.7
5.7
4.9
6.2
0
5.7
0
3.2
0
3.0
1.4
2.0
2.4
3.6
3.3
4.7
5.5
3.0
98.1
4.91
Plant
Operating
(hr)— '
9.3
7.9
11.0
9.6
4.5
6.7
6.3
7.1
7.5
0
7.6
0
6.7
0
3.9
2»1
2.8
3.7
4.4
4.0
8.7
6.4
5.0
125.2
6.26
Use Factor
(in-feed hours as
percent of plant
operating hours)
68.8
87.3
73.6
89.6
80.0
70.1
90.5
69.0
82.7
General maintenance
75.0
ADS drag conveyor down
47:8
ADS drag conveyor repair
76.9
66.7
71.4
64.9
81.8
82.5
54.0
85.9
60.0
73.4
§_/ Recorded hours from running time meter on in-feed conveyor (C-l) .
b_/ Recorded hours from running time meter on pneumatic conveying feeder.
158
-------
TABLE C-4b.
DAILY PROCESSING HOURS—REFUSE PROCESSING PLANT
FOR THE MONTH OF JULY 1976
Day
July 1976
1
2
5
6
7
8
9
12
13
14
15
16
19
20
21
22
23
26
27
28
29
30
Day of
Week
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Raw
Refuse
In- feed
(hr)£/
6.6
6.2
0
6.3
3.9
3.9
3.5
3.2
5.5
4.5
5.1
4.1
3.4
5.1
5.8
4.4
2.4
5.8
6.5
3.0
3.7
6.2
Plant
Operating
(hr)k/
8.2
8.5
0
8.3
4.7
4.9
5.4
5.1
8.1
6.0
7.0
6.1
4.8
7.0
7.0
5.6
4.3
7.0
8.5
3.4
5.7
8.0
Use Factor
(in- feed hours as
percent of plant
operating hours )
80.5
72.9
Holiday
75.9
83.0
79.6
64.8
62.7
67.9
75.0
72.9
67.2
70.8
72.9
82.9
78.6
55.8
82.9
76.5
88.2
64.9
77.5
Total
Average
99.1
4.72
133.6
6.36
74.2
a/ Recorded hours from running time meter on in-feed conveyor (C-l).
b/ Recorded hours from running time meter on pneumatic conveyor feeder.
159
-------
TABLE C-4c.
DAILY PROCESSING HOURS—REFUSE PROCESSING PLANT
FOR THE MONTH OF AUGUST 1976
Day
August 1976
2
3
4
5
6
9
10
11
12
13
16
17
18
19
20
23
24
25
26
27
30
31
Total
.Average
Day of
Week
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Raw
Refuse
In-Feed
(hr)a/
0.2
1.9
9.9
6.4
8.4
6.0
6.0
2.5
9.3
5.7
5.6
5.2
0
7.1
2.3
7.2
8.4
3.4
5.8
4.3
6.2
9.7
121.5
5.79
Plant
Operating
(hr)b/
0.7
2.7
11.7
10.9
10.5
7.1
6.7
4.2
10.4
7.4
7.8
7.0
0
10.6
3.5
9.5
11.3
3.7
6.5
5.5
8.5
11.2
157.4
7.50
Use Factor
(in-feed hours as
percent of plant
operating hours)
28.6
70.4
84.6
58.7
80.0
84.5
89.6
59.5
89.4
77.0
71.8
74.3
ADS drag conveyor maintenance
67-0
65.7
75.8
74.3
91.9
89.2
78.2
72.9
86.6
77.2
a/ Recorded
b/ Recorded
hours from
hours from
running
running
time meter on
time meter on
in-feed conveyor (C-l).
pneumatic conveying feeder.
160
-------
TABLE G-4d.
DAILY PROCESSING HOURS—REFUSE PROCESSING PLANT
FOR THE MONTH OF SEPTEMBER 1976
September 1976
1
2
3
6
7
8
9
10
13
14
15
16
17
20
21
22
23
24
27
28
29
30
Total
Average
Day of
Week
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Raw
Refuse
In-Feed
(hr)£/
0
7.5
11.1
0
0
2.7
7.9
11.9
7.5
2.8
7.7
8.2
6.5
6.5
6.4
4.5
7.0
4.3
6.5
3.6
1.8
6.2
120.6
6.35
Plant
Operating
(hr)b/
0
9.8
12.3
0
0
3.1
10.0
13.8
8.5
3.4
10.0
9.8
7.9
8.8
7.5
6.0
7.5
6-1
7.0
5.5
2.8
9.4
148.2
7.8
Use Factor
(in-feed hours as
percent of plant
operating hours)
Change shredder hammers
76.5
90.2
Labor Day holiday
Shutdown at request
of power plant
87.1
79.0
86.2
88.2
82.4
77.0
83.7
82.3
73.9
85.3
75.0
93.3
70.5
92.9
80.0
64.3
66.0
81.4
&l Recorded hours from running time meters on in-feed conveyor (C-l).
j>/ Recorded hours from running time meter on pneumatic conveying feeder
161
-------
TABLE C-4e.
DAILY PROCESSING HOURS—REFUSE PROCESSING PLANT
FOR THE MONTH OF OCTOBER 1976
Day
October 1976
Day of
Week
Raw
Refuse
In-Feed
(hr)£/
Plant
Operating
(hr)b/
Use Factor
(in- feed hours as
percent of plant
operating hours)
1
4
5
6
7
8
11
12
13
14
15
18
19
20
21
22
25
26
27
28
29
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
7.0
6.6
6.2
3.1
6.5
7.4
5.7
6.8
5.5
4.5
3.7
6.3
4.3
6.8
4.6
6.4
6.8
4.2
3.0
5.7
1.1
9.6
8.3
7.3
3.6
8.7
9.0
7.0
8.4
7.6
4.9
6.7
8.2
5.8
7.5
5.5
7.5
8.4
4.8
4.8
7.1
1.3
72.9
79.5
84.9
86.1
74.7
82.2
81.4
81.0
72.4
91.8
55.2
76.8
74.1
90.7
83.6
85.3
81.0
87.5
62.5
80.3
84.6
Total
Average
112.2
5.34
142.0
6.76
79.0
a/ Recorded hours from running time meter on in-feed conveyor (C-l).
b/ Recorded hours from running time meter on pneumatic conveying feeder.
162
-------
TABLE C-4f.
DAILY PROCESSING HOURS—REFUSE PROCESSING PLANT
FOR THE MONTH OF NOVEMBER 1976
Day
November 1976
1
2
3
4
5
6-21
22
23
24
25
26
29
30
Total
Average
Day of
Week
Monday
Tuesday
Wednesday
Thursday
Friday
Plant not
Monday
Tuesday
Wednesday
Holiday
Friday
Monday
Tuesday
Raw
Refuse
In-Feed
(hr)£/
5.1
8.0
4.8
5.2
6.9
operating
2.9
1.4
6.2
5.0
3.4
_^2
54.1
4.92
Use Factor
Plant
Operating
(hr)£/
7.6
9.3
7.1
7.1
8.5
because of fire
3.8
2.0
8.1
7.4
6.6
9.5
77.0
7.00
(in-feed hours as
percent of plant
operating hours)
67.1
86.0
67.6
73.2
81.2
damage
76.3
70.0
76.5
67.6
51.5
54.7
70.3
.a/ Recorded hours from running time meter on in-feed conveyor (C-l).
b/ Recorded hours from running time meter on pneumatic conveying feeder.
163
-------
TABLE C-4g. DAILY PROCESSING HOURS—REFUSE PROCESSING PLANT
FOR THE MONTH OF DECEMBER 1976
Day
December 1976
Day of
Week
Raw
Refuse
In-Feed
Plant
Operating
Use Factor
(in-feed hours as
percent of plant
operating hours)
1
2
3
6
7
8
9
10
13
14
15
16
17
20
21
22
23
24
27
28
29
30
31
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Mond ay
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
Monday
Tuesday
Wednesday
Thursday
Friday
6.6
6.9
6.3
5.1
7.5
2.9
7.3
5.1
5.3
6.6
2.6
8.1
3.7
7.7
8.5
4.8
4.4
2.9
3.8
6.8
5.0
8.7
3.9
10.0
8.6
8.2
6.7
9.0
3.6
8.3
6.1
7.4
8.1
3.0
8.9
6.5
12.7
9.2
5.3
7.2
3.3
5.6
7.5
6.2
6.0
5.7
Total
Average
130.5
5.67
1 163.1
7.09
80.0
al Recorded hours from running time meter on in-feed conveyor (C-l).
b/ Recorded hours from running time meter on pneumatic conveying feeder.
164
-------
TABLE C-5. WEEKLY ELECTRIC POWER CONSUMPTION FOR REFUSE PROCESSING PLANT AND STORAGE BIN
Ui
Meter No. i1
Week
(June 1976)
1-5
6-12
13-19
20-26
27-30
June total
(July 1976)
1-3
4-10
11-17
18-24
25-30
July total
(August 1976)
1-7
8-14
15-21
22-28
29-31
August total
(September 1976)
1-4
5-11
12-18
19-25
26-10
i
First
Stage
Shredder
5,600
4,200
3,220
4,060
19,600
2,520
4,200
4,620
4,760
7.560
23,660
4,060
7,280
3,920
4,340
1.820
21,420
3,360
3,500
5,180
4,760
5 . 040
2
Second
Stage
Shredder
11,620
7,700
6,020
7,420
3.920
36,680
4,620
6,020
8,820
9,100
14.000
42,560
6,020
11,340
7,000
11,760
4.200
40,320
5,600
11,900
12,460
9, 240
8.960
3
ADS Fan
3,640
3,150
2,100
3,290
1.820
14,000
1,680
2,660
3,010
2,870
3.780
14,000
2,240
4,550
2,800
4,140
1.330
15,260
1,960
3,010
3,710
3,1.50
3.43'1
4
Pneumatic
Conveying
Blower (to
Storage Bin)
3,150
2,660
1,680
3,010
1.680
12,180
1,330
1,960
2,730
2,450
3.290
11,760
1,680
3,780
2,430
3,220
1.190
12,320
1,610
2,450
3,150
2,94"
-2i*2!i
Electric Power Us<
5.
Storage Bin
and Processing
PI an' indirect
13,890
21,990
15,680
41,300
14.210
107,070
18,095
24,690
23,765
28,840
32.885
128,275
18,550
27,955
29,670
37,050
, 4.375
117,600
20,370
28,700
25,385
25,865
24.515
-d: kw-hr
5-7
Processing
Pl.int
Illllirr;, 1 -'
7,330
10,870
7,440
32,180
,8.130
65,950
13,135
16,330
13,925
20,200
22.845
86,435
9,590
18,515
21,030
28,010
535
77,680
13,810
18,220
16,105
15,945
17.>75
Total
Processing
Plant
31,340
28,580
20,460
49,960
17.440
147,780
26,120
25,080
39,720
35,040
55.640
181,600
17,920
50,200
30,840
48,080
15.480
162,520
20,320
39,920
44,480
17,120
34.61)0
7_
St orage Bin
(Storage and
Pneumatic
Conveying
to Boilers)
6,560
11,120
9,120
6.080
41,120
4,960
9,360
9,840
8,640
9.040
41,840
8,960
9,440
8,640
9,040
3.840
39,920
6,560
10,480
9,280
9, yw
6,StO
l+2+3+»+S
Toi -it
Processing
Plant an d
Stor-iEe Bin
37,900
19,700
28 700
59.0SO
189,530
28,245
39,530
42,945
48,020
220,255
32,550
54,90".
61,71"
206,970
12,900
49,560
49,885
^Ci'iSS
Sept ember total
21 ,S40
16. ISO
12.4.8SS
41.800
Z2Z.H5S
(continued)
-------
TABLE C-5. (continued)
_/
Meter No.-
Wcck
(October 1976)
1-2
3-9
10-16
17-23
24-31
October total
(November 1976)
1-6
7-13
14-20
21-27
28- JO
November total
(December 1976)
1-4
5-11
12-18
19-25
26-31
_!
First
SL.IRO
Shredder
280
4,3'.0
5,460
5,600
?'740
21,420
8,400
-0-
-0-
5,320
2.800
16,520
5,040
7,840
4,480
4,480
3.780
2
Second
St.ipe
Shredder
980
7,420
8,120
8,400
5.740
30,660
8,400
-0-
-0-
4,060
_Ji24Q
15,400
8,400
7,140
7,280
7,280
6.580
a
APS Fan
420
3,150
3,220
3,430
2.590
12,810
4,200
-0-
-0-
2,030
1.960
8,190
2,870
3,430
3,640
3,850
3.080
A
Pneum.lt.ic
Convey ing
Blower (to
SLor.ifie Bin
420
2,500
2,660
3,080
2.310
11,060
3,500
-0-
-0-
1,960
1.260
6,720
2,170
2,520
3,010
2,800
2.310
Electric Power
ji
Storage Bin
nnd Processing
.Plant Indirect
4,200
30,625
22,225
32,725
32,900
122,675
21,735
21,490
44,310
25,165
15.820
128,520
36,295
43,295
41,790
48,230
41.475
Used: KW-hr
5-7
Processing
Plant
Indirect^'
1,000
20,865
15,025
23,605
19.220
79,715
12,695
17,490
42,150
17,565
12.620
102,520
29,415
31,455
32,110
37,110
33.235
(1 + 2 -f i + 4 + 3) - 7)
Tot.il
Processing
Pi.int
3,100
38,365
34,485
44,115
35.600
155,665
37,195
17,490
42,150
30,935
21.580
149,350
47,895
52,385
50,520
55,520
*8.985
2
Stor.ir.f Btn
(Stor.ipp nnd
Pneiim.it ic
Conveying
to Roilcrs)
3,200
9,760
7,200
9,120
13.6SQ
42,960
9,040
4,000
2,160
7,600
3.200
26,000
6,880
11,840
9,680
11,120
8.240
1 + 2 + J -tjfj + ')
Total
Processing
PI. inf. ,inH
Stor.icc Bin
6,300
48,125
41.685
53,235
.49.280
198,625
46,235
21,490
44.310
38,5.35
24.760
175,350
54,775
64,225
60,200
66,640
57.225
December total
25,620
36,680
16,870
12,810
211,085
163,325
255,305
47,760
J03.065
n/ Ki lowaLL-hour mefer number or per plant clesijvi.it ion.
b/ Heat, ll^ht, vent i l.ir ion, air contli t i oni nn, m.iinr.en.incn, conveyo
ry systems.
-------
TABLE C-6. MAJOR ELECTRIC MOTORS—REFUSE PROCESSING PLANT AND STORAGE BIN
Conveyor
No.-'
Cl
C2
C3
C4
C5
C6
C7
C8
C9
CIO
Cll
C12
C13
C14
CIS
C16
C17
El
E2
E3
E4
E5
F2
F3
C19
C20
C21
C24
C25
C27
C28
F6
F7
C29
C31
C32
Lquigintnt Served
3-Phase 4.160-v motors
First stage shredder
Second stage shredder
ADS tan
Pneumatic conveying blower--plant to, storage bin
3-Phase 460-v motors
Raw refuse in-feed conveyor
Shredder No. 1 discharge conveyor
Shredder No. 2 feed conveyor
Backup raw refuse feed conveyor
Shredder No. 2 vibrating feeder conveyor
Shredder So. 2 discharge conveyor
Magnetic belt separator
ADS flight conveyor
ADS surge bin scalping roll
ADS vibrating feeder
ADS rotary airlock
Screw conveyor
Rotary airlock feeder for pneumatic conveying to storage
Vane Pump No. 1
Vane Pump No. 2
ADS heavies conveyor
ADS heavies conveyor to El
Fe-metal conveyor to C13
Rejects conveyor to Cll
Rejects conveyor to C3
Fe-metal conveyor to C13
Fe-.metal conveyor to storage
Conveyor from El to CIS
Conveyor to rejects conveyor C16
Rejects conveyor to storage
Glass or rejects to storage
ADS heavies bucket elevator
Rejects bucket elevator
Glass and rejects bucket elevator
Aluminum bucket elevator
Copper and brass bucket elevator
Chicago pump
Air compressor
Equipment hoist
Equipment trolly for hoist
Equipment bridge for trolly
Live bottom Hopper No. 1
Live bottom Hopper No. 2
Trommel screen drive
Aluminum separation conveyor
Aluminum separation conveyor
Nonferrous separation conveyor
Aluminum separation conveyor
Aluminum separation rejects conveyor
Aluminum separation conveyor
Nonferrous separation conveyor
Nonferrous rejects conveyor to C28
Nonferrous rejects conveyor to E2
Nonferrous separation conveyor
Nonferrous separation conveyor
Glass conveyor to E3
Secondary aluminum separation conveyor
Nonferrous conveyor
Motor generator (exciter 30 v 5 amp, alternator 222 KVA
0.8 power factor 120/208 v 61.5 amp)
(continued)
167
b/
kv-'
746
746
149.2
149.2
5.60
5.60
7.46
3.73
7.46
1.12
3.73
11.19
2.24
7.46
11.19
14.92
29.84
2.24
2.24
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
2.24
1.12
1.12
1.12
1.12
1.12
11.19
11.19
0.75
2.24
3.73
3.73
11.19
0.25
0.25
0.25
0.37
0.37
0.25
0.37
0.37
0.56
0.25
0.25
0.25
0.25
0.25
37.30
h£
1,000
1,000
200
200
7.5
7.5
10
5
7.5
1.5
5
15
3
10
15
20
40
3
3
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
3
1.5
1.5
1.5
1.5
1.5
15
15
1
3
5
5
15
0.33
0.33
0.33
0.5
0.5
0.33
0.5
0.5
0.75
0.33
0.33
0.33
0.33
0.33
50
Wane plate
Amperage
151
151
25.3
26
11
11
14
6.7
11
2.5
7.6
19.5
4.15
14
21
24.7
49
4.5
4.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
4.8
2.5
2.5
2.5
2.5
2.4
20.5
20.5
1.8
4.8
7.6
7.6
18.7
0.75
0.75
0.75
1
1
0.8
1.1
1
1.4
0.8
0.8
0.8
0.8
0.8
60
-------
TABLE C-6. (continued)
Conveyor
No. 3/
C22
C13
C30
NonferrouE system
Nonferrous system
Nonferrous system
Nonferrous system
Nonferrous system
n
Equipment Served
Storage bin fluffing roll A
Storage bin fluffing roll B
Storage bin fluffing roll C
Storage bin fluffing roll D
Storage bin rotary airlock feeder A
Storage bin rotary airlock feeder B
Storage bin rotary airlock feeder C
Storage bin rotary airiock feeder D
Blower for pneumatic conveyor to boiler-line A
Blower for pneumatic conveyor to boiler-line B
Blower for pneumatic conveyor to boiler-line C
Blower for pneumatic conveyor to boiler-line D
Paper bailer
Paper bailer conveyor
Wood chipper
Wood chipper feed
Wood chipper conveyor
Single-Phase 120-v Motors
Aluminum separation conveyor
Aluminum separation conveyor
Secondary aluminum separation conveyor
Nonferrous separation conveyor No. 1
Nonferrous separation conveyor No. 2
DC 240-v Motors
Storage bin sweep, conveyor - Drive No. 1
Storage bin sweep conveyor - Drive No. 2
Storage bin drag conveyor A
Storage bin drag conveyor B
Storage bin drag conveyor C
Storage bin drag conveyor D
DC 90-v Motors
Long belt drive No. 1
Long belt drive No. 2
Long belt drive No. 3
Short belt drive No. 1
Short belt drive No. 2
Nonferrous system conveyor 100/200 V
, b/
kir-
2.24
2.24
2.24
2.24
5.60
5.60
5.60
5.60
44.76
44.76
i,.76
4t.76
37.30
3.73
93.25
0.56
18.65
0.37
0.37
0.37
0.37
0.37
29.84
29.84
5.60
5.60
5.60
5.60
0.37
0.37
0.37
0.37
0.37
0.75
h£
3
3
3
3
7.5
7.5
7.5
7.5
60
60
60
60
50
5
125
0.75
25
0.5
0.5
0.5
0.5
0.5
40
40
7.5
7.5
7.5
7.5
0.5
0.5
0.5
0.5
0.5
1
Mair.fe Hatt,
Amperage
4.5
4.5
4.5
4.5
11
11
11
11
77
77
77
77
62.5
6.7
140
1.1
32.0
9.8
9.6
9.8
9.8
9.8
138
138
25.8
25.8
25.8
25.8
5.5
5.5
5 ,5
5.5
5.5
1.2/0.6
Subtotal
Power
Nonferrous svsteni
Rectifier for magnetic belt separator
Total
2,460.66 3,298.47
15
2,475.65
a/ Conveyor Ko. refers to processing flow diagram.
b/ kv Basis 0.746 ku/hp. ASTM Standard E380-74, Metric Practive Guide.
168
-------
TABLE C-7a.
PNEUMATIC CONVEYING FROM STORAGE BIN TO BOILERS OPERATING
HOURS AND AMOUNT OF RDF BURNED - JUNE 1976
Hours of
Operation
Pneumatic
Day Day of
(June 1976)
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
Monthly Total
c/
Use Factor %-
Week
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Conveying Line
A B
13.3
16.0
18.0
20.0
23.5
13.3
23.5
(24)i/
23.8
18.3
24.0
24.0
21.2
15.2
13.4
3.9
9.1
24.0
24.0
6.8
14.0
22.0
13.3 9.1
12.4
24.0
23.4
23.2
22.7
23.2
537.5 9.1
77.2 1.3
C D
14.0
18.0
22.0
24.0
21.8
14.0
24.0
(24)^
24.0
20.2
23.5
23.8
17.7
20.2
6.3
2.3
5.2
24.0
18.2
6.7
13.0
11.6
0.4 17.8
19.0
24.0
15.7
18.6
24.0
15.4
0.4 513.0
0.06 73.7
Hours
RDF
Burned
14.0
18.0
22.0
24.0
23.5
14.0
24.0
24.0
24.0
20.2
24.0
24.0
21.2
20.2
13.4
3.9
9.1
24.0
24.0
6.8
14.0
22.0
17.8
19.0
24.0
23.4
23.2
24.0
23.2
568.9
81.7
RDF
Burned
(Mg)
41.9
71.1
94.0
74.6
80.2
65.9
96.5
78.3
87.8
68.6
91.1
112.3
85.6
75.2
21.4
5.8
41.5
97.0
90.8
25.4
50.7
71.4
70.9
55.1
109.6
81.6
70.9
97.9
66.0
2,079.1
Average
Burn
Rate
(Mg/hr)
3.0
4.0
4.3
3.1
3.4
4.7
4.0
3.3
3.7
3.4
3.8
4.7
4.0
3.7
1.6
1.5
4.6
4.0
3.8
3.7
3.6
3.2
4.0
2.9
4.6
3.5
3.1
4.1
2.8
T&
a_/ Data not recorded. Estimated 24 hr.
b_/ Total Mg/total hours. Not arithmetic average of Mg/Hr.
c/ % of available hours. Available hours = 29 days (24 hr/day)
696 hr.
169
-------
TABLE C-7b.
PNEUMATIC CONVEYING FROM STORAGE BIN TO BOILERS OPERATING
HOURS AND AMOUNT OF RDF BURNED - JULY 1976
Day
(July 1976)
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
31
Monthly Total
Use Factor^/
Day of
Week
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Hours of Operation
Pneumat ic
Conveying Line
ABC
20.9
24.0
22.3
22.2
23.9
2.7
15.3
19.5
19.3
24.0
17.6
11.9
22.0
18.6
22.6
22.1
24.0
23.4
2.6
22.2
17.4
4.5
22.6
20.8
22.2
11.6
11.1
23.9
21.3
9.2 0.3
22.2 0.2
567.9 0.2 0.3
76.3% 0 0
D
23.6
23.1
23.1
24.0
0
24.0
24.0
23.9
18.7
23.9
24.0
11.9
23.0
24.0
15.8
17.8
24.0
23.7
2.7
24.0
17.6
4.4
22.7
21.4
20.6
11.3
10.7
23.9
9.4
7.5
17.5
566.2
76.1
Hours
RDF
Burned
23.6
24.0
23.1
24.0
23.9
24.0
24.0
23.9
19.3
24.0
24.0
11.9
23.0
24.0
22.6
22.1
24.0
23.7
2.7
24.0
17.6
4.5
22.7
21.4
22.2
11.6
11.1
23.9
21.3
9.2
22.2
HHIMIIHIM^BIH
623.5
83.8
RDF
Burned
(Mg)
84.4
99.8
86.4
97.3
95.7
16.2
97.6
76.3
91.9
103.3
105.5
36.9
100.4
84.8
95.1
83.2
121.3
115.9
9.3
85.6
64.7
29.9
111.4
83.4
84.5
36.4
32.7
117.6
71.4
45.0
81.6
2,445.5
Average
Burn
Rate
(Mg/hr)
3.6
4.2
3.7
4.1
4.0
0.7
4.1
3.2
4.8
4.3
4.4
3.1
4.4
3.5
4.2
3.8
5.1
4.9
3.4
3.6
3.7
6.7
4.9
3.9
3.8
3.1
3.0
4.9
3.4
4.9
3.7
3. 9 a/
aj Total Mg/total hours. Not arithmetic average of Mg/hr.
b_/ Percent of available hours. Available hours = 31 days x 24 hr/day = 744 hr.
170
-------
TABLE C-7c.
PNEUMATIC CONVEYING FROM STORAGE BIN TO BOILERS OPERATING
HOURS AND AMOUNT OF RDF BURNED - AUGUST 1976
Hours of Operation
Day
(August 1976)
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
31
Monthly Total
Use Factor^/
Day of
Week
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Pneumatic
Conveying Line
A J5_ C
24.0 0.4
9.3 0.2
0.1
23.8
14.8
16.6
21.3
23.0
13.1
22.5
22.6
24.0
24.0 0.5 0.5
17.3
24.0
9.7
24.0 0.3 0.3
8.3 0.2 0.1
23.8 0.1
15.0 0.2
23.4
19.0
18.0
3.8
15.5
23.9
13.8 2.2 2.7
23.9
23.7
22.3
23.7
578.2 3.2 3.9
77.7% 0.4% 0.57.
D
24.0
7.2
6.7
23.8
14.6
23.5
21.6
22.8
14.0
13.9
9.7
9.8
24.0
23.8
24.0
9.5
24.0
9.1
23.9
12.2
23.4
24.0
18.0
4.2
11.1
23.3
14.2
23.7
19.8
0.1
4.0
507.9
68.3%
Hours
RDF
Burned
24.0
9.3
6.7
23.8
14.8
23.5
21.6
23.0
14.0
22.5
22.6
24.0
24.0
23.8
24.0
9.7
24.0
9.1
23.9
15.0
23.4
24.0
18.0
4.2
15.5
23.9
14.2
23.9
23.7
22.3
23.7
600.1
80.7%
RDF
Burned
(Me)
110.3
30.8
9.5
102.6
78.0
106.5
103.7
115.8
57.9
109.5
126.3
126.9
159.6
101.6
172.3
68.0
124.4
34.9
103.6
50.4
96.0
106.1
64.1
14.9
31.9
88.4
39.5
79.3
93.1
43.9
47.9
2,597.7
Average
Burn
Rate
(Mg/hr)
4.6
3.3
1.4
4.3
5.3
4.5
4.8
5.0
4.1
4.9
5.6
5.3
6.7
4.3
7.2
7.0
5.2
3.8
4.3
3.4
4.1
4.4
3.6
3.5
2.1
3.7
2.8
3.3
3.9
2.0
2.0
4.3
a/ Total Mg/total hours. Not arithmetic average of Mg/hr.
b/ Percent of available hours. Available hours =31 days x 24 hr/day = 744 hr.
171
-------
TABle C-7d.
PNEUMATIC CONVEYING FROM STORAGE BIN TO BOILERS OPERATING
HOURS AND AMOUNT OF RDF BURNED - SEPTEMBER 1976
Hours of Operation
Pneumatic
(September 1976)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
25
26
27
28
29
30
Monthly Total
Use Factor^/
Day of
Week
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Sat
Sun
Mon
Tues
Wed
Thur
Conveying Line
A B
13.7
19.0
23.0
16.1
20.9
19.4
21.3
22.1
22.3
23.8
24.0
14.5
13.3
16.1
22.7
23.9
24.0
24.0
15.0
15.0
19.6
24.0
22.6
20.2
16.8
16.7
23.9
7.4
6.2
575.7
80.07.
C D
23.7
21.6
23.0
23.6
23.7
14.6
17.2
24.0
23.1
23.1
24.0
14.4
13.7
16.2
22.6
23.9
24.0
24.0
15.0
13.1
22.7
23.9
23.6
24.0
16.8
16.7
24.0
24.0
24.0
632.1
87.87.
Hours
RDF
Burned
23.7
21.6
23.0
23.6
23.7
19.4
21.3
24.0
23.1
23.8
24.0
14.5
13.7
16.2
22.7
23.9
24.0
24.0
15.0
15.0
22.7
24.0
23.6
24.0
16.8
16.7
24.0
24.0
24.0
643.9
89.4%
RDF
Burned
(Ma)
103.4
86.0
101.6
89.6
96.9
78.2
85.2
127.0
82.7
97.3
105.1
46.5
79.3
49.5
90.0
101.0
105.6
92.9
54.8
53.9
86.1
93.0
93.2
93.7
55.5
60.2
69.0
65.0
28.9
2,464.4
Average
Burn
Rate
(Mg/hr)
4.4
4.0
4.4
3.8
4.1
4.0
4.0
5.3
3.6
4.1
4.4
3.2
5.8
3.1
4.0
4.2
4.4
3.9
3.7
3.6
3.8
3.9
4.0
3.9
3.3
3.6
2.9
2.7
1.2
3.8S/
a/ Total Mg/total hours. Not arithmetic average of Mg/hr.
b/ Percent of available hours. Available hours = 30 days x 24 hours/day = 720 hours.
172
-------
TABLE G-7e.
PNEUMATIC CONVEYING FROM STORAGE BIN TO BOILERS OPERATING
HOURS AND AMOUNT OF RDF BURNED - OCTOBER 1976
Hours of Operation
Pneumatic
Day of
(October 1976)
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
31
Monthly T
Week
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
Tues
Wed
Thurs
Fri
Sat
Sun
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Monthly total
Use factor
V
Conveying Line
A B
22.3
24.0
20.2
14.9
19.9
15.7
21.7
24.0
24.0
23.9
19.7
22.8
24.0
3.7
0
2.4
14.8
22.1
24.0
23.6
22.7
23.4
23.4
23.5
24.0
23.7
24.0
24.0
23.5
22.2
23.8
625.9
84.1
C D
23.6
24.0
20.2
14.0
19.8
15.6
24.0
24.0
24.0
23.9
19.7
23.4
24.0
4.6
1.3
3.0
13.0
23.8
24.0
23.6
21.0
23.6
23.4
23.3
24.0
23.3
24.o
23.0
20.5
15.9
23.8
619.3
83.2
Hours
RDF
RDF
Burned
Burned (MR)
23.6
24.0
20.2
14.9
19.9
15.7
24.0
24.0
24.0
23.9
19.7
23.4
24.0
4.6
1.3
3.0
14.8
23.8
24.0
23.6
22.7
23.6
23.4
23.5
24.0
23.7
24.0
24.0
23.5
22.2
23.8
634.8
85.3
" ••^^^vvaM-B^^v
94.6
83.1
64.8
53.6
65.8
52.0
76.9
113.6
119.4
97.5
64.2
88.9
101.9
14.4
2.0
5.0
49.8
99.7
107.2
109.5
101.9
109.5
120.19
104.8
119.0
118.3
121.6
116.1
86.4
88.6
133.8
2684.0
Average
Burn
Rate
(Mg/hr)
4.0
3.5
3.2
3.6
3.3
3.3
3.2
4.7
5.0
4.1
3.3
3.8
4.2
3.1
1.5
1.7
3.4
4.2
4.5
4.6
- 4.5
4.6
5.1
4.5
5.0
5.0
5.1
4.8
3.7
4.0
5.6
/
4.2S/
&l Total Mg/total hours.
b/ % of available hours.
Not arithmetic average of Mg/Hr.
Available hours = 31 days (24 hr/day) = 744 hr.
173
-------
TABLE C-7f.
PNEUMATIC CONVEYING FROM STORAGE BIN TO BOILERS OPERATING
HOURS AND AMOUNT OF RDF BURNED - NOVEMBER 1976
Hours of Operation
Pneumatic
Day of
(November 1976) Week
1
2
3
4
5
6
7
8
9-22
23
24
25
26
27
28
29
Mon
Tues
Wed
Thur
Fri
Sat
Sun
Mon
: Conveying Line
ABC
14.2
23.9
23.7
23.2
24.0
24.0
24.0
8.0
System down for fire damage
Tues
Wed
Thur
Fri
Sat
Sun
Mon
30 Tues
Monthly total
Use factor^/
Use factor^/
10.1
12.4
23.6
23.3
24.0
6.8
11.7
23.9
300.8
41.8%
78.3%
D
14.0
23.8
23.8
22.8
24.0
24.0
24.0
7.9
and repair
10.0
23.6
24.0
23.4
24.0
6.8
11.0
21.1
308.2
42.8%
80.3%
Hours
RDF
Bu rn e d
14.2
23.9
23.8
23.2
24.0
24.0
24.0
8.0
10.1
23.6
24.0
23.4
24.0
6.8
11.7
23.9
312.6
43.4%
81.4%
RDF
Burned
(Mg)
62.5
86.5
100.4
98.5
121.0
121.7
106.9
24.7
30.2
74.1
93.7
175.7
135.9
35.0
38.7
90.9
1,396.4
Average
Burn
Rate
(Mg/hr)
4.4
3.6
4.2
4.2
5.0
5.1
4.5
3.1
3.0
3.1
3.9
7.5
5.7
5.1
3.3
3.8
4.5^
j/ Total Mg/total hours. Not arithmetic average of Mg/Hr.
b/ % of available hours. Available hours = 30 days (24 hr/day) = 720 hr.
_c/ % of available hours less downtime for fire damage 16 days (24 hr/day)
384 hr.
174
-------
TABLE C-7g.
PNEUMATIC CONVEYING FROM STORAGE BIN TO BOILERS OPERATING
HOURS AND AMOUNT OF RDF BURNED - DECEMBER 1976
Day of
(December 1976) Week
1 Wed
2 Thur
3 Fri
4 Sat
5 Sun
6 Mon
7 Tue
8 Wed
9 Thur
10 Fri
11 Sat
12 Sun
13 Mon
14 Tue
15 Wed
16 Thur
17 Fri
18 Sat
19 Sun
20 Mon
21 Tue
22 Wed
23 Thur
24 Fri
25 Sat
26 Sun
27 Mon
28 Tues
29 Wed
30 Thur
31 Fri
Monthly totals
Use factor^
A
24.0
24.0
24.0
21.2
23.6
21.2
24.0
24.0
21.1
24.0
21.5
8.6
10.9
18.6
20.8
23.9
15.5
21.8
23.5
17.9
19.3
15.6
14.4
12.2
22.4
6.0
10.9
22.9
21.2
17.0
24.0
600.0
80.6%
Hours of Operation
Pneumatic
Conveying Line
BCD
24.0
24.0
24.0
23.2
24.0
24.0
24.0
<- 24.0
21.7
24.0
24.0
8.9
1.2
11.7
22.4
23.8
23.6
23.0
23.6
19.8
24.0
17.4
14.5
16.7
23.1
5.9
9.3
21.4
14.0
20.0
24.0
609.2
81.9%
Hours
RDF
Burned
24.0
24.0
24.0
23.2
24.0
24.0
24.0
24.0
21.7
24.0
24.0
8.9
10.9
18.6
22.4
23.9
23.6
23.0
23.6
19.8
24.0
17.4
14.5
16.7
23.1
6.0
10.9
22.9
21.2
20.0
24.0
636.3
85.5%
RDF
Burned
(Ms)
98.9
88.9
122.1
106.4
112.4
90.9
127.4
84.2
99.5
104.8
103.0
30.0
21.8
56.1
73.8
79.4
61.6
62.5
24.7
34.7
72.9
51.2
101.7
53.3
83.9
18.5
41.0
78.5
65.6
56.7
83.2
2,289.6
Average
Burn
Rate
(Mg/hr)
4.1
3.7'
5.1
4.6
4.7
3.8
5.3
3.5
4.6
4.4
4.3
3.4
2.0
3.0
3.3
3.3
2.6
2.7
1.0
1.8
3.0
2.9
7.0
3.2
3.6
3.1
3.8
3.4
3.1
2.8
3.5
3.6S'
.a/ Total Mg/total hours.
b/ % of available hours.
Not arithmetic average of Mg/Hr.
Available hours = 31 days (24 hr/day) = 744 hr.
175
-------
TABLE C-8a. DAILY RECORD OF PNEUMATIC CONVEYING DOWNTIME AND MAINTENANCE
JUNE 1976 (Lines A, B, C, D from storage bin to boilers)
Day Line
(June 1976)
2 A
3 A
D
4 A
A
D
D
5 A
D
6 A
D
7 A
D
8 A
A
D
9 A
A and D
Location
Feeder
Feeder
Elbow D2
Before
Boiler 6
Elbow A8
Elbow Dl
Line
Fluffing
roll
Elbow Al
Elbow Dl
Diverter
Feeder
Before
Boiler 6
Elbow A2
Feeder
System
Description
Jammed
Jammed twice (piece of
rubber tire)
Leak
Leak
Leak
Plugged due to piece of
wood
Airlock feeder jammed
Replace V-belt drive
Plugged due to 457 x
914 mm piece of sheet
metal
Jammed
Leak
Leak
Repaired and installed
new feeder knife
Installed new feeder
knives
Leak
Plugged
Leak at diverter
Jammed
Change wear plate
(continued)
176
-------
TABLE C-8a. (continued)
Day
(June 1976)
10
11
12
13
14
15
16
17
18
19
20
21
Line
A
D
A
A
A
A
A
D
A
D
D
A
D
D
D
D
D
Location
Feed chute
Elbow D2
Elbow A2
Drive
Drag conveyor
System
Line
System
Line
Feeder
System
Feeder
Diverter
Line
Line
Elbow D4
Diverter
(continued)
177
Description
Plugged
Plugged
Replaced elbow
New rubber spider installed
in direct coupling
Zero-speed switch malfunctioned
Leak
Plugged between elbows A2
and A3
Leak
None
Plugged
Jammed
Plugged. Motor overload
circuit activated
Jammed due to roller from
sweep conveyer
Plugged
Leak
Storage bin down
Sweep conveyor off
Leak
Leak
Plugged three times due to
large pieces of plastic
Storage bin down
-------
TABLE C-8a. (continued)
Day
(June 1976)
22
Line
23
24
25
26
27
A
A
A
A
D
D
D
A
D
Location
Flange on
spool
piece at
Boiler 7
Feeder
Feeder
System
System
Feeder
Line
Diverter
Elbow A6
System
Line
System
Diverter
System
Diverter
Description
Leak
Jammed and motor over-
load circuit activated
Jammed (twice)
Leak (twice) shut down to
repair holes
Plugged
Jammed due to tire inner-
tube
Install new length of
line at storage bin
Plugged due to large
pieces of plastic and
cloth
(Note: Both A and D lines
shut down twice due to
low boiler steam pressure)
Plugged
Line shut down due to
poor boiler combustion
Install new length of
line at storage bin
Plugged
Leak
Jammed
Plugged due to plywood,
plastic and wire
(continued)
178
-------
TABLE C-8a. (continued)
Day Line Location Description
(June 1976)
28 A System Plugged due to plastic
and wood
A Elbow A6 Hole
D Line Leak
29 A System Off for maintenance
A Elbow A7 Plugged
A Line Leak
D Drag conveyor Roller on drag conveyor
froze
30 A System Off for maintenance
D Feeder Fluffing roll not operative
New knife installed in
feeder
D System Plugged
179
-------
TABLE C-8b. DAILY RECORD OF PNEUMATIC CONVEYING DOWNTIME AND MAINTENANCE
JULY 1976 (Lines A, B, C, D from storage bin to boilers)
Day Line
(July 1976)
1 A
D
D
2 D
3 A
D
4 A
A
D
5 A
A
D
6 A
A
7 A
D
8 A
D
D
9
Location
Feeder
Feed conveyor
Diverter
Feed conveyor
Feeder
Elbow A7
Diverter
Feeder
Elbow A7
Line
Elbow A7
Elbow A7
Line
Elbow A7
Diverter
Elbows A2
and A3
Line
Elbow A7
Feeder
Diverter
Storage bin
(continued)
180
Description
Installed new knife and
new flange gasket
Motor overload circuit
activated
Lubrication and patch
two holes
Motor overload circuit
activated
Installed new knife blades
Plugged twice
Plugged
Jammed
Plugged due to wood and
plastic
Plugged twice
Plugged
Leak
Plugged
Leak
Plugged
New experimental elbow in-
stalled at A2 and old A2
elbow installed at A3
Leak
Plugged three times
Plugged
Plugged
Changed elbow immediately
before receiving cyclone
on pneumatic line from
processing plant to
storage bin
-------
TABLE C-8b. (continued)
Day Line
(July 1976)
10 D
11 A
A
A
12
13 A and D
A
14 A
A
15 A
D
16 D
17
18
20 A
A
Location
Line
Elbow Al
Diverter
Elbow A7
Processing
plant
Feeder
Elbow A6
Elbow A9
Before
Boiler 6
Elbow A7
Diverter
Before
Boiler 5
Elbow Al
Elbow A9
Description
Leaks
Leak
Plugged
Plugged due to wood and
plastic
Leak in elbow at processing
plant
Replace feeder knife
Plugged four times
Plugged four times
Leak
Replaced wear back
Plugged twice due to wood
Hole in chute into boiler
None
None
Leak
Plugged
21
System
Shut down for general
maintenance
22
None
"(continued)
181
-------
TABLE C-8c. DAILY RECORD OF PNEUMATIC CONVEYING DOWNTIME AND MAINTENANCE
AUGUST 1976 (Lines A, B, C, D from storage bin to boilers)
Day
(August 1976)
2
3
4
6
7
9
10
11
Line
A
A
A and D
D
A
A
D
A
D
A
A
D
A
D
D
A and D
Location
Elbow A9
Feeder
System
Elbow before
Boiler 6
Before
Boiler 6
Feeder
Elbow D8
Feeder
Line
Diverter
Instrumenta-
tion
Line
Line
Line
Elbow A8
Line
Instrumenta-
tion
Feeder
Description
Maintenance
Plugged
Shut down for maintenance
Leak in wear back plate
Leak
Plugged
Leak
Plugged
Leaks
Replaced diverter with
straight length of pipe
Counter not working. Shut
down for 1 hr to check
counter
Plugged
Leak
Plugged
Repair
Plugged
Counter not working
Installed new feeder
knives
12
13
14
D
A and D
Elbow D8
System
(continued)
182
Leak
None
Shut down for maintenance
-------
TABLE C-8c. (continued)
Day
(August 1976)
15
16
17
19
21
22
23
24
25
26
27
28
29
30
31
Line
•^••••^••v
A
D
A
D
A
D
A and D
A
D
A
A
A
D
A
A
A
D
D
A
A
A and D
Location
Elbow A4
Elbow D8
System
Line
Feeder
Line
System
Line
Line
Line between
elbows A7
and A8
Feeder
Feeder
Feeder
Line
System
Feeder
Fluffing roll
Feeder
Feeder
Feeder
Feeder
Description
None
Repair
Leak
None
0.3 hr downtime for
maintenance
Plugged (0.1 hr
downtime)
Jammed
Plugged twice
General maintenance
Leak and plugged 3 times
Plugged by piece of rubber tire
Plugged
Maintenance and installed new
feeder knives
Jammed twice
Jammed
Plugged
Plugged
Jammed
Out of service
Jammed 4 times
Jammed
Jammed
Jammed
183
-------
TABLE C-8d.
DAILY RECORD OF PNEUMATIC CONVEYING DOWNTIME AND MAINTENANCE -
SEPTEMBER 1976 (Lines A, B, C, D from storage bin to boilers)
Day Line
(September 1976)
1
2 A
A
A
D
3 A
A
A
4 A
A
A
D
D
5 A
A
D
6 A
A
A
A
D
D
D
7 A
A
A
D
.«M^BMB^MM**»M^*V«B*«M*.M«^ta^V>**««
Location
Feeder
Line
Feeder
Elbow D7
Line
Feeder
Feeder
Feeder
NA
Feeder
Line
Elbow D3
Feeder
Feeder
Feeder
Feeder
Feeder
Feeder
Feeder
Feeder
Feeder and
line at
bin
Feeder
Feeder
Feeder
Feeder
Feeder
Description
None
Jammed with rubber
Jammed with rubber
Jammed
Leak
Jammed
Plugged with board
Plugged
Jammed
Plugged with tire
Jammed with wire
Leak
Leak
Plugged with tire
Plugged with rubber
Plugged with tire
Jammed
Plugged with tire
Plugged with rubber
Jammed
Jammed
Plugged with rubber and wood
Jammed
Plugged with rubber
Plugged with rubber
Plugged with tire and wire
Plugged with rubber
(continued)
184
-------
TABLE C-8d. (continued)
Day
(September 1976)
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Line Location
A Feeder
A Feeder
A Feeder
A Feeder
A Elbow A4
D Elbow D3
A Feeder
D Line
A Feeder
D Feeder
D Line
(continued)
185
Description
Plugged with wire
Plugged with rubber
Jammed with wire
Jammed
Maintenance: welded elbow
None
None
None
None
None
None
None
None
None
Jammed with belting
Leak
Jammed with rubber
Jammed causing motor over-
load
Leak
-------
TABLE C-8d. (continued)
Day Line Location
(September 1976)
23
24 D Feeder
Description
None
Installed new knife
blade
25
26
27
28
29
30
A
A
A
A
Feeder
Feeder
System
System
Jammed
Jammed with rubber
None
None
None
General
General
maintenance
maintenance
186
-------
TABLE C-8e. DAILY RECORD OF PNEUMATIC CONVEYING DOWNTIME AND MAINTENANCE -
OCTOBER 1976 (Lines A, B, C, D from storage bin to boilers)
Day Line Location
(October 1976)
1 A Line
2
3
4 D Feeders
5
6
7 A Instrumenta-
tion
A Line
D Instrumenta-
tion
8 A Feeder
9
10 A Out -feed
conveyor
11
12 A A3 Elbow
D Line
A Line
13
14
15
16
Description
Leak
None
None
Jammed with steel bar
None
None
Adjust new set point
system
Plugged due to electrical failure
Adjust new set point
system
Jammed
None
Stopped, restarted
None
Leak
Plugged with rubber
Plugged with tires
None
None
None
None
(continued)
187
-------
TABLE C-8e. (continued)
Day
(October 1976)
17
18
19
20
21
22
23
24
25
26
27
28
29
Line
A
D
D
A
A
D
A
A
D
A
D
D
A
A
D
A
D
A
A
A
A
D
Location
Line
Line
Feeder
Line
Line
Line
Feeder
Feeder
Feeder
A7 Elbow
D4 Elbow
D4 Elbow
Feeder
D8 Elbow
A8 Elbow
Line
Feeder
A8 Elbow
D4 Elbow
D8 Elbow
(continued)
188
Description
Plugged with rubber
Plugged with rubber
Jammed
Plugged with rubber
Plugged with carpeting
Plugged
Jammed with steel
Jammed with rubber
Jammed with rubber
None
Leak
Leak
Leak
Jammed
Off for repair
Leak
Off for general maintenance
Off for general maintenance
None
None
Leak
Plugged
Jammed
None
Replaced
Plugged
Plugged
-------
TABLE C-8e. (continued)
Day Line Location Description
(October 1976)
30 A Conveyor Jammed with wire and wood
D Hi/Lo pressure valve tripped
D Line Plugged
31 A Line Plugged with innertube
A Feeder Plugged with rubber
D Jammed with wire
D Jammed with sticks
189
-------
TABLE C-8f. DAILY RECORD OF PNEUMATIC CONVEYING DOWNTIME AND MAINTENANCE -
NOVEMBER 1976 (Lines A, B, C, D from storage bin to boilers)
Day
(November 1976)
1
2
3
4
5
6-21
22
23
24
25
26
27
28
30
Line
A
D
D
A
D
A
A
D
D
All
A
A
A
D
A
D
A
D
Location
Feeder
Elbow D-3
Feeder
Out- feed
conveyor
Line
Feeder
Fluffing roll
Feeder
Fluffing roll
System
Feeder
Feeder
A4-A5
Feeder
Feeder
At boiler
No. 6
Elbow A- 9
Out-feed
conveyor
Description
Jammed with rubber
Leak
Jammed
Jammed
Leak
Replace knife blades
Cleaned
Replace knife blades
Cleaned
None
Not operating because of November 6
fire in processing plant.
None
None
Jammed
Replace knife blades
New spool
Replace knife blades
Jammed
None
None
Leak
Leak
Jammed
190
-------
TABLE G-8g. DAILY RECORD OF PNEUMATIC CONVEYING DOWNTIME AND MAINTENANCE
DECEMBER 1976 (Lines A, B, C, D from storage bin to
boilers)
••^•feV0MB**^HHMM*4MMMCll*^HW^tMMM0MVHIIBll*M
Day
(December 1976)
1
2
4
6
8
9
10
11
13
14
15
17
20
•••••••••••••••••'•^•^•M
Line
D
0
D
A
D
A
A
A
A
A
A
D
A
A
D
A
A
A
D
A
A
A
A
D
A
A
A
A
Location
System
Feed conveyor
System
Line
Line
Line
System
Feeder
Feeder
System
Feeder
Feeder
Feeder
System
System
Feeder
Feeder
Line
System
System
Feeder
Feeder
Feeder
System
Feeder
Feeder
Feeder
Feeder
Description
Shut down for general maintenance
Jammed
Shut down for general maintenance
Plugged
Plugged
Repair leak
Shut down for general maintenance
Jammed
Jammed
Shut down for testing purposes
Installed new feeder knives
Installed new feeder knives
Jammed due to rubber tire
Jammed
Not operating properly
Jammed
Jammed due to wire
Plugged
Not operating properly
Shut down for adjustments
Jammed with rubber
Jammed with wire
Jammed with wire
Shut down for adjustments
Jammed
Jammed with rubber
Motor overload circuit activated
Motor overload circuit activated
(continued)
191
-------
TABLE C-8g. (continued)
Day Line
(December 1976)
Location
Description
21
A
A
Line
Feeder
Chute into No. 6 boiler plugged
Jammed
22
A
A
23
24
25
27
28
29
30
A
D
A
D
A
D
Feeder Jammed
System Shut down to replace feeder knives
and to divert RDF to No. 6 boiler
from No. 5
System Shut down to replace feeder knives.
Installed new spool at bin wall and
repaired elbow D-8.
Line Plugged
Line Plugged
Feeder Jammed
Elbow A-8 Repaired
Elbow D-8 Repaired
Line Plugged
System General maintenance
System General maintenance
System Down. No reason given.
192
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TABLE G-9. DAILY RECORD OF STORAGE BIN DOWNTIME AND MAINTENANCE
Day
(June 1976) Description
16 Sweep drive broke down. Replaced cam follower.
17 Sweep drive broke down. Replaced 4 verticle rollers.
18 Sweep drive broke down. Replaced thrust wheel.
21 General maintenance on sweep drive.
23 Clean up.
24 Clean up and general maintenance.
25 Problems with sweep drive.
26 General maintenance on sweep drive.
27 Problems with sweep drive.
28 Clean up and general maintenance.
29 Clean up.
30 Clean up and general maintenance. Electrical maintenance
on sweep drive.
(July 1976)
1 Repaired lubricators.
2 Installed cat-walk on top of bin.
6 Clean up. Repaired cat-walk on top of bin.
7 Clean up.
9 Clean up.
12 Clean up and full inspection of storage bin.
13. Clean up.
14 Cleaned trap in pneumatic conveying blower.
15 Clean up and full inspection of storage bin.
(continued)
193
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TABLE C-9. (continued)
Day
(August 1976)
1
2
3
5
6
7
8
10
16
18
20
22
29
(September 1976)
8
9
12
13
14
15
19
20
23
26
27
Description
Sweep drive broke down
Sweep drive stopped, timer off
Repair sweep drive
Sweep drive broke down, weight fell off tension pulley
Repair weight cable on sweep drive
Weight cable on sweep drive broken
Weight cable on sweep drive broken
Weight fell off cable on sweep drive
Sweep drive maintenance
Sweep drive maintenance
Broken chain on sweep drive
Sweep drive off 5 cm on out feed conveyor
Sweep drive down
Minor fire from welding
Bin empty
Bin empty
Bin empty
Bin empty
Bin empty
Bin empty
Bin empty
Bin empty
Repair balance cable on sweep drive
Bin empty
Bin empty
(continued)
194
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TABLE C-9. (continued)
Day
(October 1976) Description
5 Modification to system
6 Sweep drive timer went out
18 Sweep drive stopped for maintenance
(November 1976)
No failures occurred this month
(December 1976J
8 Leak in storage bin
12 Bin empty
13 Bin empty part of day
18 Sweep drive weight fall off
19 Bin empty part of day
20 Bin empty part of day
24 Stopped to clean clinkers from No. 6 boiler
25 Shut down for reasons other than equipment malfunction
26 Bin empty part of day
27 Bin empty part of day
28 Maintenance on sweep drive deflector plate
29 Bin empty part of day
30 Shut down to change diverter from boiler No. 6 to No.5
195
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APPENDIX D - CAPITAL EXPENDITURES AMES, IOWA, SOLID WASTE RECOVERY SYSTEM
TABLE D. CAPITAL EXPENDITURES - AMES, IOWA, SOLID WASTE RECOVERY SYSTEM
Refuse Processing Plant ($)
Equipment:
Shredders, 5 conveyors associated with shredders and ferrous
metals separator 373,282
Air density separator system 182,854
Pneumatic conveying system to storage bin 30,017
Raw refuse scale system 32,769
Plant conveyors other than 5 units associated with the
shredders 104,600
Nonferrous metal separation system 251,130
Plant hoist to move equipment 24,520
Electric substation including 4160 V. transformer 44,636
Motor starters and electrical disconnectors for 4160 V motors 52,707
Wood chipping machine 32.319
Total equipment 1,128,834
The estimated useful life of this class of assets is considered
to be 12 yr, with no salvage value, in accordance with guide-
ft I
lines established by the Internal Revenue Service.— Annual
depreciation is $91,376, or $7,615/month, on a straight line
basis.
Building and Apparatus:
Excavations, foundations, concrete, and plant building 1,515,589
Reinforcing steel 250,934
Masonry 5,727
Miscellaneous metal 164,768
Carpentry 20,534
Doors and frames 23,112
Mechanical 414,105
Electrical 314,020
Subtotal 2,708,789
Engineering 278,903
Total capital cost - refuse processing plant 4,116,526
(continued)
196
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TABLE D. (continued)
Refuse Processing Plant ($)
The estimated useful life of this asset is 45 yr, in
accordance with Internal Revenue Service guidelines.
The asset is considered to have no salvage value.
Annual depreciation is $90,760, or $7,563/month on
a straight line basis.
RDF Storage and Firing Facility
Equipment:
Storage bin 413,353
Pneumatic conveying systems to boilers 120,068
Boiler modifications 178,989
Electric substation 28.797
Total equipment 741,206
Construction:
Storage bin excavation and concrete 137,939
Pneumatic conveying vault excavation and concrete 14,303
Reinforcing steel 83,645
Masonry 1,909
Miscellaneous metal 8,672
Carpentry 5,133
Doors and frames 5,778
Mechanical 188,479
Electrical 314.070
Subtotal 759,928
Engineering 97,993
Total capital cost RDF storage and firing facility 1,599,127
This class of assets is considered to have an estimated
useful life of 20 yr, with no salvage value, in accordance
with Internal Revenue Service guidelines. Annual deprecia-
tion is $79,956, or $6,663/month on a straight line basis.
(continued)
197
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TABLE D. (continued)
RDF Storage and Firing Facility ($)
Miscellaneous Equipment:
Tools, front end loader, trailers, etc. 164,827
These assets are considered to have an estimated useful
life of 6 yr with no salvage value in accordance with
Internal Revenue Service guidelines. Annual deprecia-
tion is $27,471, or $2,289/month on a straight line
basis.
Land:
City block for processing plant 82,841
Additional 10 acres at existing city landfill 15,000
Land improvements (streets, sewers, etc.) 10,000
Total land 108,068
Start-up expenses:
Operating cost (July 1-December 31, 1975) 71,603
Interim financing cost (interest only) 21,511
Cost of bond insurance 10,139
Interest expense on bond issue^' (March 1-December 1, 1975) 218,325
Total start-up 321,578
This asset class is considered to be amortizable over a period
of 5 yr. There is no known Internal Revenue Service guide-
line; the period selected is based upon accepted industry
practice. Annual amortization is $64,315, or $5,359/month
on a straight line basis.
Grand total capital cost 6,310,126
a/ Debentures: $5,300,000 principal amount at 5.37, interest, serialized
for redemption over a 20-yr period, City of Ames Municipal Bonds
Redemption Schedule. Principle payments are due annually on December
1 in accordance with the following schedule:
1976-1979 $200,000
1980-1994 $300,000
Interest is payable semiannually on June 1 and December 1.
198
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-6QO/2-77-205
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
EVALUATION OF THE AMES SOLID WASTE RECOVERY SYSTEM;
Part I - Summary of Environmental Emissions:
Equipment, Facilities, and Economic Evaluations
5. REPORT DATE
November 1977 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
J. C. Even, S. K. Adams, P. Gheresus, A. W. Joensen,
J. L. Hall, D. E. Fiscus, and C. A. Romine
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
City of Ames
Ames, Iowa 50011
1O. PROGRAM ELEMENT NO.
EHE 624
11. CONTRACT/GRANT NO.
Grant No. R803903010
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory—Gin.,OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Interim,Feb.5,1976-Feb.4,1977
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Part I of a three part report.
Project Officer: Carlton C. Wiles, 684-7881
16. ABSTRACT
This report describes the results of the following tests and evaluations of the Ames,
Iowa, refuse processing plant during the year 1976: characterization of the refuse
derived fuel (RDF) produced; equipment and plant performance evaluations; an analysis
of plant maintenance and manpower requirements; and an analysis of plant operating
costs. Also included is a brief summary of the boiler environmental emissions and
boiler performance when mixtures of coal and RDF are burned. Complete discussion of
the boiler emissions and performance will be available in separate reports. During
the year the plant processed 37,136 Mg of municipal solid waste. Average as received
heating value of the RDF produced was 13,050 kJ/kg at 23.0% moisture and 17.4% ash.
The net cost of operating the refuse processing plant after credits were given for
the RDF, recovered metals and dump fees was $18.90/Mg of municipal solid waste
received. The economic model of the plant showed that a volume increase is the most
attractive method of reducing the net cost.
17.
KEY WORDS AND DOCUMENT ANALYSIS
a.
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Refuse
Evaluation
Combustion
Air pollution
Economic analysis
Maintenance
Operating costs
Municipal wastes
Particulates
Stationary sources
Capital costs
13B
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report}
Unclassified
20. SECURITY CLASS (This page}
Unclassified
21. NO. OF PAGES
213
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
199
ft U.S. GOVERNMENT PRINTING OFFICE 1977- 757-140/6590
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