PB-214960
Baling Solid Waste to  Conserve
Sanitary Landfill Space
a feasibility study
San Diego  City, California
prepared for
Environmental Protection Agency
Office of Solid Waste Management Programs
1973
                     Distributed By:
                     National Technical Information Service
                     U. S. DEPARTMENT OF COMMERCE

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  BIBLIOGRAPHIC DATA  11- Report No.
  SHEET              I   -~^ EPA-SW-44D-73
 4. Title and Subtitle
  Baling Solid Waste  to Conserve  Sanitary  Landfill Space;
  a Feasibility Study
                                                3. Recipient's Accession No.
                                                ^§214-960
                                                5' Report Date
                                                          1973
                                                6.
 7. Author(s)
  City of San Diego
                                                8. Performing Organization Kept.
                                                  No.
 9. Performing Organization Name and Address

  City of  San Diego
  San Diego,  California   92101
                                                10. Project/Task/Work Unit No.
                                                11. JpJttKSeX/Gram No.

                                                       G06-EC-00061
 12. Sponsoring Organization Name and Address

  U.S. Environmental  Protection  Agency
  Office of  Solid Waste Management Programs
  Washington,  D.C.   20460
                                                13. Type of Report & Period
                                                   Covered
                                                          Final
                                                14.
 15. Supplementary Notes
 16. Abstracts      ,

 •In addition to the purpose indicated by the  title, the study was  also designed to:
  (1)  explore the possibilities  of reducing  direct haul  distances;  (2)  study the use
  of solid waste bales  as fill in  reclaiming small canyons near residential  areas;
  (3)  compare the compaction obtained by baling with that achieved  through conventional
  methods; (4)  investigate baling  as an integral feature of possible transfer station
  operations;  (5) develop yardsticks, formulas, and techniques that might be useful to
  other communities in  dealing with their solid waste  collection and disposal problems./
 17. Key Words and Document Analysis. 17a. Descriptors

  *Waste disposal, Urban  areas,  *Baling, Compacting
 17b. Identifiers/Open-Ended Terms
  *Solid waste  disposal,  solid waste  transfer  stations
 17c. COSATI Field/Group
13B
 18. Availability Statement

            Release to public
<=-ORM NTIS-3S (REV. 3-72)
                                    19.. Security Class (This
                                      Report)
                                         UNCLASSIFIED
                                    20. Security Class (This
                                      Page
                                         UNCLASSIFIED
21. No. of Paxes
22. .Price
                                                                                 USCOMM-DC I4952-P72
                                                  \- CL/

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                                                 EPA-SW-MD-73
      BALING SOLID WASTE TO CONSERVE SANITARY LANDFILL SPACE

                        A Feasibility Study
     This publication (SW-44d) reports on work performed under
Federal solid waste management demonstration grant no. G06-EC-00061
               to the CITY  OF SAN  DIEGO, CALIFORNIA,
          and is reproduced as received from the grantee.
               U.S.  ENVIRONMENTAL PROTECTION AGENCY

                              1973

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    This  report  has  been reviewed by the 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 commercial  products  constitute
    endorsement  or recommendation for use by the U.S.  Government,
   An  environmental  protection  publication  (SW-44d)  in  the
   solid waste management  series.
                                111
Preceding page blank

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                                   PREFACE
     Conserving sanitary  landfill space and minimizing transport costs are two
important objectives in the processing of solid waste materials.  Processing--
changing solid wastes in  some fashion—may mean converting the wastes into a
more stable form or into  a different physical state by chemical, thermal, or
biological means.  Or it  may mean mechanical alteration such as by size
reduction and densification.  Baling solid wastes, the subject of this report,
is an example of the latter kind of processing.

     The investigation performed by the City of San Diego, California, and
described in this document has contributed significantly to advancing the
state of the art in the solid waste processing field.  This report, plus the
recently published results of a Federal grant to the City of Chicago entitled
High-Pressure Compaction  and Baling of Solid Waste (SW-32d), constitute prime
literature presently available on the subject of baling solid wastes.

     In the present study the feasibility of baling solid wastes.is examined
to see if the technique could significantly prolong the life of both existing
and future sanitary landfills.  The effectiveness of solid waste baling
under two circumstances is evaluated:  (1) using unshredded solid waste at
a local baling site; (2)  using shredded solid waste baled offsite at a
commercial facility.  The densities achieved are compared to those obtained
using conventional sanitary landfill techniques.  In addition, the possi-
bilities of using a baler transfer station are explored.

     As a follow-up to this study a pilot baling plant is currently in
operation in San Diego with the support of a solid waste demonstration
grant from the U.S. Environmental Protection Agency (EPA).  The facility
has been active since the summer of 1971 and is presently processing
approximately 100 tons of solid waste per day.  A final report covering
the operation of the pilot plant and evaluation of the complete baling-
transport-disposal system is scheduled for completion in late 1973 and
subsequent publication.

     Eric Quartly served as Project Director for the City of San Diego
while David Arella and Keith Grems served as EPA project engineers for the
completed project reported herein.
                                    —JOHN T. TALTY, Director
                                      Processing and Disposal Division
                                     IV

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                                TABLE OF CONTENTS
Chapter
  II      Summary and Conclusions
          Abstract                                                              ix

          Introduction                                                           1

              Nature of the Project   	  .....           1
              Methods of Procedure    	           2
              Evaluation of the Progress of the Project   	           3
              Definition of Terms Used in the Report	           3
              General Description of the City   	           3
              Brief History of Refuse Operations in San Diego    ....           4
              Summary of the Report	           7
              Recapitulation of Conclusions   	           9

 III      Physical Feasibility of Baling Refuse   	          11

              The Baling Process    	          11
              The Baling of Refuse    	          13
              Local Refuse Baling Tests    	  .....          13
              Manufacturer's Refuse Baling Demonstration    .  .  *  .  .  .          23
              Comparison of the Local and Factory Tests      	          30
              Summary of the Chapter	          37

  IV      Economic Feasibility of Baler  Transfer Stations    ......          38

              Conventional Transfer Stations     	          38
              The Proposed Pilot Baling  Transfer Station    	          41
              Cost of the Proposed Pilot Station    	          46
              Conventional versus Baling Transfer Stations     	          46
              Transfer Station Location	          49
              Basis for the Economic Feasibility Study    	          54
              Data for Direct Haul Cost  Study   	          54
              The Economics of Direct Haul	          58
              Comparative Costs of Conventional and  Baling
                  Transfer Stations   	          61
              Cost Comparisons    	  ......          61
              Summary of the Chapter    	          65

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                         TABLE OF CONTENTS  (Continued)
Chapter
   V      A Look Ahead    	         66

              The Proposed Demonstration Project    	         66
              Objectives of the Project     	         67
              Method of Procedure	         67
              Evaluating the Project    	 .......         68
              Areas of Special Interest   	         69
              Factors Contributing to Bale Compaction   	• • •         69
              Limiting the Pilot Plant to City-collected Refuse   ...         70
              Reclamation of Small Canyons  	         71
              Summary of the Chapter	         73

          Appendix

              1.  Comparison of San Diego with Six Selected Citias  . .         75
              2.  Letter of Inquiry and Mailing List of Baler
                     Manufacturers    	         76-79
              3.  Notes on Manufacturer's Demonstration of Refuse
                     Baling   	         80
              4.  Mathematics of Direct Haul Costs    .........         84
              5.  Cost of Pre-shredding Municipal Refuse  	         86

   Bibliography	 .....         88
                                        vi

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                                 LIST OF TABLES
Number                                                                        Page
   1      Summary of Local Baling Test Results	          19

   2      Summary of Ratings of Bale Characteristics, Local
              Baling Test   	          22

   3      Estimated Capital Expenditures for Pilot Baling
              Transfer Station    	          47

   4      Estimated Current Operating Expenses of Pilot Baling
              Transfer Station for One Year   	          48

   5      Factors for Consideration in Location of Transfer
              Stations    	          50

   6      Weekly Round Trip Mileage Increase, Direct Haul to
              Murphy-Shepherd Landfill versus Arizona Landfill  ....          57

   7      Estimated Annual Costs of a Full-scale Conventional
              Transfer Station	          62

   8      Estimated Annual Costs of a Full-scale Baling Transfer
              Station   	          63

   9      Annual Savings in Disposal Costs     .. 	          64

  10      Comparative Annual Costs of Conventional and Baling
              Transfer Stations		          64
                                      vii

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                                 LIST OF FIGURES
Number
 1-4      Design and Operation of the Local Test Facility   ,  . .' . .  .       15-18

   5      Weights, Volumes, and Densities of Bales
              Produced in Local Baling Test   ...... 	          20

 6-9      Views of Local Bale Disposal Experiment	       24-27

10-11     Factory Refuse Baling Demonstration   	       28-29

12-13     Comparison of Raw Materials, Local and
              Factory Tests   .	       32-33

14-15     Comparison of the Finished Product    	       34-35

   16     Baling Pressure versus Bale Density   	          36

   17     Views of a Conventional Transfer Station    	          40

   18     Pilot Baling Transfer Station   	  	          43

19-20     Elevations of Pilot Baling Station	       44-45

   21     Three Views of a Small Canyon   	          51

   22     View of Proposed Baling Transfer Station Site   	          53
                                      viii

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                         ABSTRACT
 Project

 Study and Investigation

 Title

 Investigate and Evaluate Feasibility of Refuse Baling as a Means
 of Conserving Sanitary Fill Space

 Objectives

 To investigate  and analyze the physical and technical feasibility
 of baling municipal refuse and the economic feasibility of using
 this  process in combination with the transfer station concept.

 Procedures

 Municipal refuse was actually baled in a local test program and in
 a demonstration by a baler manufacturer.  Compaction thus obtained
 was compared with that obtained by present landfill methods.  A
 preliminary design for a proposed pilot baling transfer station
 was prepared.   Comparative costs were estimated for (l) longer
 direct haul to  a more remote fill, (2) full-scale conventional
 transfer  station operation, and (3) full-scale baling transfer sta-
 tion  operation.

 Findings

 The process of baling municipal refuse is physically and technically
 feasible with presently available equipment and economically feasi-
ble when  combined with the transfer station concept.  Greater compac-
 tion  can be achieved by baling than by the use of standard compaction
methods (bulldozer or compactor) in sanitary landfills.  Under
 certain frequently met conditions, baling transfer stations are more
 economical than longer direct hauls by collection vehicles.  In the
 station capacity ranges studied, baling transfer stations are more
 economical than conventional transfer stations.  Construction of a
pilot baling station is recommended in order to test the findings
and tentative conclusions of this study and investigation project.
                                 ix

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                               CHAPTER I

                         INTRO D U C T I 0 N
 Increasing national concern about the serious and urgent problem of solid
 waste  disposal  is  shared by the citizens of San Diego and by their municipal
 government.  This  concern has been the principal motivation for the city's
 undertaking, in cooperation with the United States Public Health Service,* the
 project described  in this report..

 San Diego  has its  own unique problems to face in this field aud its own
 special complex of available resources to solve them.  Although the project
 has been primarily oriented toward these local considerations, an important
 secondary  motivation has been the hope that this city's investigations and
 findings may be helpful to other municipalities confronted by similar refuse
 disposal problems.

 Nature of  the Project

 This study and  investigation project, entitled "Investigate and Evaluate
 Feasibility of  Refuse Baling as a Means of Conserving Sanitary Fill Space,"
 was jointly financed by city funds and a grant from the Solid Wastes Program
 of the Public Health Service's National Center for Urban and Industrial
 Health.  It represents the first year of a possible three-year project in
 which  the  initial  study and investigation phase would be followed by a demon-
 stration phase  involving the construction and operation of a pilot baling
 transfer station.

 The purposes of the first phase, reported herein, were not only (as the title
 indicates) to determine the feasibility of refuse baling as a means of con-
 serving the life of sanitary fill sites but also (l) to explore the possibili-
 ties of reducing direct haul distances, (2) to study the utilization of refuse
 bales  as fill in the reclamation of small canyons in close proximity to
 residential areas, (3) to compare compaction obtainable by baling with that
 obtained by conventional methods,  (U) to investigate baling as an integral
 feature of possible transfer station operation,  and (5) to develop yardsticks,
 formulas, and techniques that may be useful to other communities in dealing
 with refuse collection and disposal problems.

 Locally the project received direction and leadership from the Public Works
 Director of the City of San Diego and was coordinated by the Senior Adminis-
 trative Analyst of the Public Works Department.   The full-time staff consisted
 of an Associate Civil Engineer (borrowed from the Engineering Department for
 the duration of the project) and,  assisting him,  an Administrative Analyst and
 an Administrative Trainee.  Other professional members of the Engineering and
 Public Works Departments served part-time as consultants and resource people.
 Clerical workers, equipment operators,  and laborers were provided either on a
 scheduled part-time basis or for temporary periods as required by the progress
 of the work.


    *Federal responsibility for this project now lies with the U.S.  Environ-
mental Protection Agency.

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 In a real sense,  the  city's  Chollas  Sanitary Landfill  served as a practical
 laboratory for certain phases  of  the project -  notably (l) an extensive study
 of refuse compaction  by conventional methods based  in  part on sampling of the
 extent of refuse  dumping at  the fill by private contractors and citizens and
 (2) actual testing of refuse baling  using a  local baler leased for this pur-
 pose .

 Methods of Procedure

 In its investigation  of various methods of refuse baling, the staff sent
 inquiries to a total  of fifty  baler  manufacturers throughout the country to
 learn the types,  characteristics, and capabilities  of  equipment available for
 or adaptable to the baling of  refuse.   Replies  were received from twenty-five
 companies.

 It was found that only a few firms manufacture  equipment that can be readily
 adapted to the baling of municipal refuse.   Still fewer have actually done
 research and.development work  leading toward the production of such equipment
 or the adaptation of  existing  models  to this  purpose.  There is evidence, how-
 ever,  of increasing awareness  on  the  part of  manufacturers that there may be
 a  potential market for balers  specifically designed to process solid wastes.
 The special problems  of baling municipal  refuse economically on a large scale
 and the cooperative efforts,that  have been made by  the City of San Diego and
 an interested baler manufacturer  to  solve those problems are discussed in
 Chapter III of this report.

 The project staff also canvassed  twenty-two local business firms to determine
 the types of balers being used commercially  in this city and to locate balers
 that might  be available and  suitable for  the  initial testing of refuse baling.
 This search resulted  in the  city's finding and leasing a balar which,although
 it had relatively low compression capability  as compared with modern, heavy-
 duty equipment, could be used  for testing purposes  on a systematic basis.  A
 substantial number of bales were produced, their densities were calculated,
 and such characteristics as  shape, ease of handling, and absence of odor were
 evaluated.   A number  of completed bales were  stacked or "nested" in a simu-
 lated landfill situation in  order to investigate the best equipment and
 procedures  for this purpose and to discover the kinds of problems that might
 arise  in the process.   A description of these experiments and their results
 will also be found in Chapter  III.

 Both of  these  approaches--cooperation with a baler manufacturer and the local
 testing  experiment—were  found to be valuable in (l) exploration of the com-
 paction  potentialities  and the technical feasibility of baling municipal
 refuse and  (2) preliminary evaluation of various types of available baling
 and auxiliary  equipment  to determine which is most suitable for1use in a
 possible pilot operation.

 In  order  to  evaluate  the economic feasibility of refuse baling,  the staff con-
 ducted sampling, engineering, and statistical studies of compaction obtained
by  present  sanitary fill techniques and compiled data on costs  of present
methods.

These were compared with the estimated costs of possible alternative opera-
tions involving baling.  Specifically, evaluations were made  of  the economics

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 of a "baling transfer station as  compared with a  conventional transfer  station
 and also with direct haul to the fill  site.   These  studies are presented in
 Chapter IV..

 Also set forth in Chapter IV are (l) design  concepts, preliminary drawings,
 specifications,  and cost  estimates  for a prototype  baling transfer station,
 (2) related equipment and manpower  studies,  and  (3) survey studies to  deter-
 mine the optimum site location for  such a  station.                   -

 Evaluation  of the P^ogess of the Project

 Weekly staff meetings were held  throughout the course of the  project.  These
 were attended regularly "by the Project Director  and the Project Coordinator
 and from time to time by  other officials of  the  Public Works Department, the
 Sanitation  Division,  and  the State  of  California.   At these sessions the prog-
 ress of the work was  appraised,  problems were  discussed, and subsequent steps
 were planned.  Detailed written  progress reports were submitted to the Project
 Director once a  week  and  once a  month  to the National Center for Urban and
 Industrial  Health,  Public Health Service.  The Project Officer for the National
 Center made several trips to San Diego to  discuss concepts and project plans
 and to review progress of the study.

 Definitions of Terms  Used in the Report

 In general  any technical  terminology used  in this report follows the usage and
 definitions of standard reference works in the literature of the field, par-
 ticularly Refuse Collection Practice and Municipal  Refuse Disposal prepared by
 the American Public Works Association with the assistance of the United States
 Public  Health  Service and published by  the Public Administration Service.
 Terms  that  do  not appear  in these sources, or  that  are peculiar to San Diego,
 are defined as they appear in the context  of the report.

 General Description of the City

 San Diego is a coastal southern  California city of 69^,000 population, third
 largest in  the state  and,  according to  the United States Bureau of the Census,
 eighteenth  largest  in the  nation.   It has experienced a rapid rate of growth
 in recent decades and this  trend is expected to continue for the foreseeable
 future.   It  is not heavily industrialized.   In 1960 it had,  for each 100,000
 people,  only nineteen manufacturing establishments of twenty or more employees
 each as  compared with 95  in Cincinnati and 63  in Seattle!    Its central retail
business area  is comparable with that of other American cities of its size,
 and smaller  shopping  centers are scattered throughout the  city.  An extensive
 Naval establishment is clustered in and around its excellent harbor,  and a
large Naval air  station is located in the northern section of the city.  These
 installations together with Marine facilities in the city and its metropolitan
area combine  to give San Diego a strong military flavor.
  See Appendix 1 for a comparison of San Diego with six selected cities of
 comparable size, with respect to population,  housing,  industry,  and climate.

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 The city's subtropical climate,  natural points of interest,  and varied rec-
 reational facilities attract large numbers of tourists  and other visitors,
 particularly but by no means exclusively during the summer months.   Perhaps
 for the same reasons there is a  considerable segment of retired persons in the
 population.

 Transient or relatively transient visitors to the city  are a significant fac-
 tor in shaping the special character of San Diego's refuse problem.   The daily
 average number of visitors in the city is more than 85,000.   According to a
 recent study by the local Economic Research Department  of  Copley Press,  Inc.,
 "the visitor industry is San Diego's third largest source  of basic income.   It
 ranks ahead of agriculture and behind manufacturing and Navy payrolls  as a
 source of new money for San Diego."  Military personnel living  on board ships,
 in barracks, or,  often with dependents,  in housing units at major military
 installations numbered about 60,000 in 196?-   These more or  less temporary
 residents,  together with such smaller groups  as college students living in
 dormitories,  patients at hospitals,  and institutional inmates or prisoners,
 total approximately 150,000 - in themselves the equivalent of a good-sized
 city - and while they are here they produce a substantial  quantity of  refuse.

 Spread over an area of 310 square miles,  San  Diego has  a population  density
 of 2,180 persons to the square mile.   In 1960 this density was  2,944  (the
 decrease since then is due to the annexation  of additional outlying areas to
 the city),  as compared with 15,157 in Boston  and 3,966  in  San Antonio.   The
 city's Planning Department reported in October,  1967, that only 38 per cent
 of San Diego's land area is urbanized (this is  the portion,  incidentally, in
 which the city has established refuse collection routes),  "with most of  the
 remaining land devoted to agriculture and open  livestock grazing."  The
 Department  went on to say that within the city  limits "there are large acre-
 ages of completely vacant or unused land,  much  of it  in steeply sloping  hill-
 sides  and canyons."  Even in those areas  where  there has been urbanized
 development the  terrain is intersected by numerous  canyons and  there is,
 therefore,  more  than the usual proportion of  dead-end streets.

 Seventy per cent of the  city's 215,000  housing  units are single  family dwell-
 ings.   In 1960 this percentage was  71 as  compared with  16 per cent in Boston
 and 56 per  cent  in Pittsburgh.

 Brief  History of  Refuse  Operation in  San  Diego

 The  year 1919 marked the  first assumption by  the  city of responsibility for
 the  solid waste problem  in an organized way.  At  that time the Sanitation
 Division was  created and took over the task of collecting refuse, which had
 previously been either burned on  the  householder's premises or hauled away by
 private  contractors.  Some  of the policies initiated then have remained
 largely  unchanged to  the  present  day.  The Sanitation Division has never had-
 a major  reorganization, although  it was decentralized to a degree in 1952
when, due to  growth of the city,   its work could no longer be handled from a
 single operations  station.  Both the early-morning collection "sweep" through
 the  downtown business area by a fleet of vehicles and the "daily route method"
 of collection  in residential areas, in which a specific  area is  assigned to
 each crew each' day, have been used throughout the intervening period.  The
 Division has been  greatly expanded in personnel, facilities,  and budget over

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.the years  and many technical improvements  have  been introduced, but  the  basic
 principles of administrative organization  and of  scheduling  collection that
 were found to be successful in the  beginning are  believed  to be still valid
 today.

 The physical and mechanical changes in sanitation service  techniques that
 have been  most apparent  to  the average citizen  have been in  the kinds of col-
 lection vehicles used.   There has been a progressive adoption  of  improved
 transportation equipment, as it became available,  for more efficient perform-
 ance, more attractive  appearance, and  better protection of the public health.
 Horse-drawn wagons were  replaced by motorized open-box trucks  in  1926 and  in
 turn by enclosed packer  trucks in 1946.  These  were the cylindrical, side-
 loading type until 1955  when they were replaced by the box type with rear-
 loading hoppers.   In 1965 the city  began a transition from twenty-yard packer
 trucks  with three-man  crews to twenty-five yarders with two-man crews.   This
 change  is  still in progress.

 Until 1958 garbage was collected separately twice  a week and sold to hog
 farms.   Since that date  it  has been integrated  with other  refuse  and collected
 once a  week in residential  areas.   A requirement  has been  in effect  since  1924
 that garbage and,  later, all refuse to be  collected must be  set out  at the
 curb or (in sections of  the city where they exist)  in alleys.

 Refuse  other than garbage was disposed of  by open  burning  at various dumps in
 the city before 1951 when the present  "fill, compact, and  cover"  method  was
 adopted.   The Chollas  sanitary landfill  in the  southeastern  part  of  the  city
 was opened in that year  and is still in  use.  The  other two  existing facili-
 ties, Arizona landfill in the central  section and  Miramar  landfill on the
 north side,  were  opened  in  1952 and 1959 respectively.  In the meantime  the
 Mission Bay Fill  was in  operation from 1952 through 1959.

 By  1958, when it  was integrated with other refuse,  garbage had become so small
 a proportion of the total bulk of solid  waste materials that it posed no
 serious problems  at the  landfills except at the Miramar location.  Since this
 facility is  adjacent to  the Naval Air  Station,  sea gulls attracted by the  gar-
 bage constituted  a hazard to  aircraft  and  have had  to be systematically
 frightened away by the noise  of shotgun  blasts  and  by amplifying  on  a public
 address system the recorded cries of gulls in distress.  This  system has been
 highly  effective  and successful for three  years now.

 In  August,  1966,  the city began to  use a heavy compactor instead  of  a bull-
 dozer to obtain increased compaction at  the Arizona landfill.  Aerial surveys
 have been  utilized in studies  of available volume  and remaining life expect-
 ance of landfills  since  1963.

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                                  CHAPTER II

                           SUMMARY AND CONCLUSIONS
 The  historical development and present character of the refuse collection and
 disposal services provided "by the City of San Diego have been influenced to
 some degree by climate and topography.  In all essential respects> however,
 this operation is comparable with those of many other municipalities.  The
 findings of this study and investigation project, although based primarily on
 San  Diego experience and conditions, are believed to have general applica-
 bility.

 At the present time San Diego is generating more than a half million tons of
 refuse a year or about four and one-third pounds a person a day.  Rapid popu-
 lation growth and gradual increases in the per capita generation of refuse are
 expected to double this tonnage by 1985-  While this growing demand will in
 itself result in higher current expenditures for sanitation service, its im-
 pact will be compounded by the exhaustion of existing favorably located land-
 fills, the necessity for acquiring new, more remote locations, and accelerated
 increases in costs due to longer direct hauls by collection vehicles.  This
 situation, which is expected to become critical in San Diego within seven
 years, has already been or soon will be confronted by many another community.

 For  these reasons a number of new techniques and procedures that give promise
 of mitigating the problem are being explored here and elsewhere under the
 solid waste disposal program of the United States Public Health Service.  Among
 these is  the possibility investigated in this project and described in this
 report -  the baling of refuse.  Each of the findings and conclusions arrived
 at during the course of the project, summarized in this chapter, is more fully
 described and substantiated in the appropriate chapter of the report.

 As part  of the evaluation of the feasibility of refuse baling as a means of
 conserving sanitary landfill space, a major objective of this project, it was
 necessary to compare the compaction (l) now being obtained by conventional
 landfill  methods with (2) that potentially obtainable by baling.  The first of
 these was investigated by making a field survey at one of the city's landfills
 to determine the weight and compacted volume of refuse now being deposited,
 and  the second by actually baling refuse in controlled test situations.

 The  tonnage of refuse brought to the landfill by private citizens and commer-
 cial contractors is not normally weighed.   However,  in the field survey, this
 tonnage was determined by counting and classifying all private vehicles enter-
 ing  the landfill during a fourteen-week test period, weighing a 23 per cent
 sample during the first six-week's phase of the test, and developing average
weight factors for each vehicle classification.  Estimates of private tonnage
 thus  derived were added to the actual recorded tonnage brought in by city col-
 lection trucks.   This combined tonnage was compared with the compacted volume
 of the materials as determined by aerial volumetric  surveys.  In three sepa-
 rate  phases, the study examined differences in densities obtained by using
 different types of compacting equipment and by varying the amount of water
 added manually to the refuse during compaction.
      Preceding page blank

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 It was found that compaction ranged between 1,189 and 1,383 pounds to the
 cubic yard,  that better results were  obtained with a compactor than with a
 bulldozer, and that the application of  larger amounts of water to the refuse
 improved effectiveness.

 The feasibility of baling refuse and  the degree of compaction obtainable by
 this method  were investigated at two  levels:  (l) ah extended local test was
 conducted in which unprocessed refuse was baled in a leased light-duty baler
 installed at a test facility especially constructed for this purpose, and (2)
 arrangements were made  for a demonstration of refuse baling by an interested ;
 baler manufacturer,  using modern, heavy-duty equipment.

 In the local baling test a total of U8.5 tons of typical city-collected refuse
 was processed during a  five-week period into 162 bales averaging 599 pounds
 apiece in weight and 689 pounds to  the  cubic yard in density.  These bales
 were classified as to composition of  the refuse and were rated as to such
 characteristics as shape,  handling  ease, odor absence, fines retention, and
 liquid retention.   As a second phase  of this program, 6k additional bales were
 produced and "nested" in a simulated  landfill situation.

 On January 9,  1968,  at  its plant in Bellevue, Ohio, the American Baler Company
 conducted a  demonstration of baling pre-shredded municipal refuse.  The four
 complete bales  that were produced ranged from 1,500 to 2,^90 pounds in weight,
 from 0.92 to 1.56  cubic yards  in volume, and from 1,U66 to 1,593 pounds to
 the cubic yard in  density.  On the basis of this experience and its background
 of previous  knowledge in the field, ttie company believes that densities
 close to 1,900 pounds to the cubic yard are practicable.  Bale densities of
 this magnitude  probably approach the maximum obtainable without resorting to
 relatively slow, cumbersome, and expensive multiple stage baling presses.

 Findings  in both the local test and the factory demonstration tended to
 supplement and  reinforce  each  other.  The balers used in both tests were of
 the same  basic  horizontal  design which lends itself to more continuous, higher
 production than other types,   Locally it was shown that ordinary city-
 collected refuse can be  successfully processed,  even without pre-shredding,
 into reasonably well-formed bales which generally maintain their integrity
 during transportation and  disposal.  Since the local test involved a larger
 quantity  of materials (an  estimated 65 tons in all as compared with perhaps
 five or six tons at Bellevue) and extended over a period of time,  it estab-
 lished the feasibility  of baling refuse which varies considerably in composi-
 tion and  moisture content from day to day and from one collection area to
 another.  The Bellevue test provided persuasive  evidence of the desirability
 of  shredding the refuse before it is fed into the baler and of using baling
 equipment of high compression capability.   The factory-produced bales were not
 only denser but better shaped, with sharp,  well-defined corners and relatively
 r.mooth surfaces, and they maintained their integrity without appreciable
distortion during handling.

 Densities obtained locally are not competitive with the approximately 1,380
pounds to the cubic yard obtainable by efficient landfill methods, but the
compaction obtained at the factory exceeds  that  level.   Based on  the  compac-
tion actually reached in that test (1,593  pounds  to the  cubic  yard) and
                                      8

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allowing five per cent of volume for voids between bales in place in a land-
fill, the space required per ton for refuse in bales would be 91 Per cent of
that required with our best present landfill methods.  If the greater density
(1,890 pounds to the cubic yard) predicted by the company were reached and the
same allowance for voids made, the space required per ton would be 77 per cent
of that required with conventional methods.  It follows that the potential
saving in landfill life that is realizable by baling can be expected to fall
between 9 and 23 per cent.

It is felt that the potential economic benefits of baling refuse can be fully
realized, however, only in the operational setting of a transfer station.  The
project staff made preliminary studies of the economic feasibility of a full-
scale baling transfer station where the exhaustion of an existing favorably
located landfill would require longer direct haul to a more remote landfill by
collection vehicles.  It was concluded that, under the San Diego conditions
studied, when the additional round-;trip distance required per truck by longer
direct haul exceeds about 10.1 miles the baling transfer station would be more
economical than direct hauling.  It also appears that, in the station capacity
ranges studied (300 to 350 tons a day), a net savings can be realized by bal-
ing despite the baling operating costs because of the reduction in the cost of
land for the station site, in rehaul equipment, and in compaction.equipment
and labor at the landfill.  This would make a baling transfer station (fully
equipped with balers, a hogger, and conveyors) more economical than a conven-
tional station in which refuse is simply transferred from collection to rehaul
vehicles.  However, it should be noted that this conclusion might not be valid
if the comparison were made with a conventional transfer station of larger
capacity and consequently greater efficiency.

A pilot baling transfer station is needed (l) to test these tentative conclu-
sions under actual production conditions, (2) to refine baling techniques and
routines, (3) to ascertain the optimum moisture content of the refuse being
baled, (U) to compare the compaction obtainable with pre-shredded versus
unprocessed refuse, (5) to determine and deal with any possible nuisance
factors or health hazards (such as noise, dust, odor, and vector breeding) that
may be encountered in the operation, (6) to develop effective practices in
placing the bales in a landfill, (7) to explore the feasibility of other means
of bale disposal, such as in the reclamation of small canyons near residential
areas, and (8) to develop accurate cost comparisons.  As a means of implement-
ing and proving out the combined baling and transfer concepts,  a pilot baling
transfer station would in the long view be a potentially rewarding investment.

                      Recapitulation of Conclusions

1.  The problem of disposing of solid waste  materials,  already formidable,  is
    growing in magnitude and complexity as urban populations continue to
    increase and the per capital production  of refuse continues to  rise.

2.  In many communities using sanitary landfills for refuse disposal this
    problem is compounded by the imminent exhaustion of favorably located
    landfill facilities and the prospect of  longer direct hauls by  collection
    vehicles.

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3.  The urgency of the situation has prompted investigation of a number of new
    approaches that might offer alternative solutions to the problem.  Among
    these is the concept of baling refuse.

k.  The process of baling refuse is physically and technically feasible with
    presently available equipment and economically feasible when combined with
    the transfer station concept.

5.  Greater compaction can be achieved by baling than by use of standard com-
    paction methods (bulldozer or compactor) in sanitary landfills.

6.  Under certain frequently met conditions, baling transfer stations are more
    economical than longer direct hauls by collection vehicles.

7«  In the station capacity ranges studied, baling transfer stations  are more
    economical than conventional transfer stations.

8.  A pilot baling station is needed to test the findings and tentative con-
    clusions of this study and investigation project.
                                     10

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                              CHAPTER III

                 PHYSICAL FEASIBILITY OF BALING REFUSE
 A review and appraisal has been made of the background,  present status, and
 expected growth of the tasks of solid waste collection and disposal in San Diego.
 It is evident that both the magnitude and the cost of the city's already for-
 midable task in performing these functions will increase in the future.  San
 Diego is not unique in this respect.  There are few if any municipalities using
 landfills for solid waste disposal that do not face to some degree the prospect
 of mounting quantities of refuse, dwindling space in favorably located disposal
 sites, and greater expenditures for sanitation operations.

, This situation here and elsewhere has led to the exploration and consideration
 of a number of new techniques and procedures that may give promise of allevi-
 ating the solid waste disposal problem.  Among these is  the possibility inves-
 tigated in this project and described in this report - the baling of refuse.
'The physical feasibility of applying this process in the solid waste field is
 discussed in this chapter.   Its economic feasibility, particularly as related
 to the transfer station concept, is examined in Chapter  IV.

 The Baling Process

 Baling may be defined as the process of applying pressure to loose, compress-
 ible materials within an enclosure and binding the compacted mass while it is
 in a confined condition.  The.resultant object is a bale.

 Widely used for many years  in industry and agriculture,  the baling process is
 perhaps the simplest and most economical form of packaging.   In essence no
 encasing or wrapping are required to maintain the integrity of the bale and
 the cohesion of its contents.   The compaction inherent in the process contri-
 butes to the conservation of space and consequently to economies in storage
 and transportation.   In the weights in which they are usually produced on the
 farm arid in the factory, bales  are readily handled by manual or mechanical
 means.   Typically their surfaces are rectangular in shape and relatively
 smooth and they can be stacked  and nested economically without excessive voids
 and waste space.   For these reasons baling is often used in the packaging of
 certain types of  raw materials,  scrap, staple commodities, and manufactured
 products.   The United States Department of Commerce has  listed 53 different
 commodities that  have been  successfully baled for transit.    These range from
 excelsior to textiles and from  feathers to tobacco.
     Quoted  in  Stern,  W.   The package engineering handbook.   Rev.  version.
      Chicago, Board  Products  Publishing Company,  [1949].   p.  38.
                                       11

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 In  most  applications  in  agriculture and  industry, baling  is  used  for  the  com-
 pressing and packaging of  relatively homogeneous materials - cotton,  hay,
 paper  stock, and  rags, for example.   With  such  commodities the  process  is
 relatively standardized  and more or less trouble free because the materials
 are relatively  uniform in  composition and  in  the size and shape of  their
 constituent elements.  They present few  surprises.  Foreign  objects that might
 damage the mechanism  or  require  frequent adjustments in the  process are seldom
 encountered.  Potential  compressibility  is known within reasonable  limits.

 A major  complication  in  adapting the baling process to municipal  refuse is
 that this  material  lacks such homogeneity  and predictability.   It.is  true that
 the composition and character of mixed solid  wastes have  been analyzed  and
 described  in a  general way.  On  the average,  its characteristics  may  be dis-
 tinctive in different parts of the  country, from city to  city,  and  even from area
 to  area  within  the  same  community.   Nevertheless, any given  batch fed into a
 baler  hopper may  differ  markedly from that average, may present unusual prob-
 lems,  and  in the  completed bale  may vary widely from the  norm in  density.
 These  problems  strongly  indicate a  requirement  to investigate and evaluate
 the need for certain  techniques  and procedures preliminary to the actual bal-
 ing process:  (1) some means of  controlling the composition  of  the input, such
 as  by  limiting  it to  city-collected refuse and by imposing certain restrictions
 on  the kinds of materials  that will be picked up, (2) sorting out non-balable
 items, arid (3)  pre-shredding the materials to reduce their heterogeneity.

 Balers are manufactured  in a number  of different types and sizes  to meet the
 special  requirements imposed by  the  quantity  and character of the materials to
 be  baled.   They may be stationary or  portable.  They range in size from small,
 manually operated balers that are suitable for small offices  or .plants  to
 powerful briquetter presses that  can  reduce an automobile to  a  small  cube of
 compacted  metal.

 Heavy, production type balers are hydraulically or electrically operated.  They
 are generally classified into two major  types depending on the  direction of
 movement of  the compressing ram:  (1) vertical stroke balers, which are sub-
 classified  as down-stroke  or up-stroke (so called "pit" type) balers  and (2)
 horizontal  stroke balers.   In vertical stroke balers the materials are  com-
 pressed between a moving ram (a piston with a flat faceplate  or "platen" the
 size of  one  face of the bale) and the  fixed floor or ceiling  of the compres-
 sion chamber.   Vertical stroke balers have the disadvantage  that  time and
 effort are  required to remove the completed bale before the  chamber can be re-
 charged  and  the production of a new bale begun.  This type has  the advantage,
 at  least theoretically, of  greater  compaction for the same expenditure  of
 energy.  Compound or multiple stage balers, in which pressure is  applied
 vertically  and  then horizontally  or vice versa, produce still greater compac-
 tion but are even slower in operation.   In the horizontal stroke baler  the
 ram moves  laterally against the end of the bale being formed  and  in the
 process not only compresses the materials but also pushes the bales (the one
being formed and one or more already  completed) toward ej ection through an
 elongated  chamber and out  its open end.  The  completed bales  still lodged in
 the chamber before ejection act as a plug and 'provide resistance  to the ram

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In  the production of a new bale.  A tension adjustment at the perimeter of the
open  end of  the  chamber allows  this resistance to be increased or decreased as
needed.' The process is continuous in that a completed bale need not be
removed before starting a new one.  A minor disadvantage of this type of baler
is  that it is harder to feed than a pit baler because the material must be
elevated.  The theoretical loss of compacting power inherent in this design is
probably more than offset by the fact that the bale is automatically ejected.
As  a  matter  of fact the horizontal stroke baler appears to be the only type
presently available that has a  production rate high enough to handle the large
quantities of material that are normally involved in a refuse operation.

In  most applications, bales are customarily bound with wire or with flat metal
straps.  In  the  present state of the art, these must be tied or secured manu-
ally  which is time-consuming and expensive for a high production operation.
The chief obstacle in the way of automatic tying appears to be the expansi-
bility of the material and the  spring-back of the compacted bale when the
pressure of  the  ram is relieved.  Another difficulty arises from the clogging
(with compacted  material) of slots in the face of the platen, through which
the wires or straps must be threaded.  The solution of these problems - and
they  do not  seem to be mechanically insurmountable - will be a major break-
through.  There  are indications that one or more baler manufacturers are
developing devices for this purpose and that there is a reasonable prospect of
success in the near future.

The Baling of Refuse

As  part of the evaluation of the feasibility of refuse baling as a means of
conserving sanitary landfill space, a major objective of this project, it is
necessary to appraise and compare the effectiveness of two methods of compac-
tion:  (1) by conventional landfill techniques and (2) by baling.   The first
of  these was investigated by making field surveys to determine the weight and
compacted volume of refuse now being deposited, and the second by actually
baling refuse in controlled test situations.   Other objectives of the tests
were  to investigate the mechanical feasibility of baling refuse and to deter-
mine what problems might be encountered with the disposal of completed bales
in  a  simulated landfill situation.

The feasibility  of baling solid waste materials and the degree of compaction
obtainable by this method were investigated at two levels:  (1) ah. extensive
local test was conducted using a leased light-duty baler installed at a test
facility especially constructed for this purpose, and (2) arrangements were
made  for a demonstration of refuse baling by an interested baler manufacturer,
using modern, heavy-duty equipment.

Local Refuse Baling Tests

Early in the project, local San Diego business firms having balers were sur-
veyed so that arrangements could be made to conduct actual testing of the
feasibility of baling refuse.   Originally it was contemplated that this test-
ing would be done on the baler owner's premises on week-ends or at other odd
times when he was not using the equipment.   When it was found that a baler
could be leased outright for a period of time, however, it was decided to
                                      13

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 install  it  on  city  property  and  thus  create  a  test  situation  that would  be
 better controlled,  more  comprehensive,  and more  realistic  than would have been
 possible under the  original  plan.  Accordingly,  a test  facility was designed
 and  constructed on  city  property near the Chollas sanitary landfill.   The
 criteria for the selection of  a  baling  test  site were accessibility, proximity
 to a disposal  site,  suitable topography, and availability  of  power and water.
 As constructed the  test  facility had,  at an  upper level, a paved dump  area
 adjacent to a  wooden ramp and  chute designed for feeding refuse into the leased
 "Balemaster" horizontal  stroke baler  mounted on  a concrete pad at a lower level.
 It was equipped with a hoist for handling completed bales,  was.provided  with an
 access road and a paved  area for the  maneuvering of mobile service equipment
 (refuse  packer truck, dump truck,, and a leased skip loader),  and was completely
 enclosed by a  chain  link fence.  Power  and water were brought in from  nearby
 sources.  Views showing  the  design and  operation of the test  facility  appear in
 Plates 1 to 4  on pages 15 to 18.

 The  local baler test program began on December 11,  1967, and  ended on  January
 19,  1968.   It  was conducted  on an experimental rather than  a  production  basis.
 On a typical day, three  to four  tons  of refuse were handled and from twelve to
 fourteen bales were  produced.  They were measured and weighed, their densities
 were computed,  they  were classified as  to composition, and  a  number of bale
 characteristics such as  shape, ease of  handling, and absence  of odors  were
 evaluated.

 The  nucleus of  the four-man  crew consisted of an equipment  operator and  a
 laborer  from the Public  Works  Department.  One full-time member of the project
 staff was assigned regularly to  the test program crew and  the other two  full-
 titae members served  alternately  in this capacity, so that  all three became
 thoroughly  conversant with the process  through active participation in the
 work.

 During the  test  period this  crew processed 48.5  tons city-collected refuse into
 162  bales averaging  599  pounds apiece in weight  and 689 pounds to the  cubic
 yard in  density.  The bales  ranged in weight from 335 to 900 pounds, in volume
 from 0.3  to 1.4  cubic yards, and in density  from 370 to 905 pounds to  the cubic
 yard.  A  day-by-day  summary  of weights and densities recorded is shown in Table
 1 on page 19 and  the distributions of weights, volumes, and densities of all
 the  bales produced during the  test period are shown graphically in Plate 5 on
 page 20.

 The  composition  of the refuse baled was classified by visual inspection and
 found to be about 21 per cent  "typical San Diego refuse," about 17 per cent
 "excessive garbage," about 60 per cent "excessive paper," and about two per cent
 "excessive prunings."  None  of the bales were judged to fall in the other two
 composition categories that had been set up for the test - "excessive fines" and
 "excessive water."

 It was found that there were substantial differences in the average densities
of bales  in each of  the three leading categories described above (omitting
 "excessive prunings" as having too few cases to support a valid comparison).
The average density  of those bales judged to be composed of "typical San Diego
                                      14

-------
                 DESIGN AND OPERATION  OF THE LOCAL TEST FACILITY       FIGURE  1
'
                                                             General view of
                                                             test  facility
                                                             during  construction
      Refuse is  dumped
      at the upper level
                                                           A  skip loader  cuts
                                                           into the pile  of
                                                           refuse
                                                                 This page is reproduced at the
                                                                 back of the report by a different
                                                                 reproduction method  to provide
                                                                 better detail.
                                          15

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        DESIGN AND OPERATION OF THE  LOCAL TEST FACILITY
FIGURE 2
End view of upper
ramp leading to
baler hopper
                                                   Refuse "bridging"
                                                   at throat  of  chute
                                                   has tc be  manually
                                                   dislodged
 Water  is applied
 to  refuse as it
 enters chute
NOT  REPRODUCIBLE

-------
         DESIGN AND OPERATION OF THE LOCAL TEST FACILITY    .FIGURE 3

    Baling wires
    are  tied manually
                                                     Refuse descending
                                                     chute into baler
                                                     chamber
                                                    rom "xfyensi.'yr"
                                                   of baler cnamber
NOT  REPRODUCIBLE
17

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    DESIGN AND OPERATION OF THE  LOCAL TEST FACILITY
FIGURE 4
  Bales are pushed
  along roller conveyor
                                                     Hoisting bale
                                                     from conveyor
  Bales are placed in
  dump truck for
  transportation to
  the fill
NOT  REPRODUCIBLE
                                     18

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                                   TABLE 1

                    .  SUMMARY OF LOCAL BALING TEST RESULTS  .
              (WEIGHTS AND DENSITIES ROUNDED TO NEAREST FIVE POUNDS)
Weight of Bales

Weeks
1





Days
Dec.






11
12
13
14
15
Sub -total
2

Dec.

20
21
Sub -total
3


Dec.


26
27
29
Tons of
Refuse
.800
1.775
4.200
3-700
1.225
11.700
2.025
1.125
3.150
4.925
2.150
5.100
No. of
Bales
3
6
13
13
7
42
7
3
10
13
7
20

Max.
575
600
750
800
350
800
615
750
750
780
665
600
(Lbs)
Mln.
450
550
575
335
350
335
550
750
550
735
575
450
Density of Bales
(Lb/Cu.Yd)
Ave.
535
575
645
570
350
555
580
750
630
760
615 .
520
Max.
600
835
675
830
405
835
700
780
780
850
630
600
Min.
475
680
590
575
370
370
620
780
620
700
575
495
Ave,
555
760
630
730
390
635
665
780
700
775
600
450
Sub-total
12.175
40
780   450    610
850    495    615
4 Jan
Sub-total
5 Jan
Sub -total
TOTALS AND
AVERAGES
• 3
4
5

. 8
9
10


5-075
4.075
2.500
11.700
3.650
2.250
3.900
9.800
48.525
16
13
8
37
13
8
12
33
162
750
900
650
900
650
590
690
690
900
600
575
625
575
500
540
625
500
335
635
630
640
630
560
565
650
595
600
895
900
780
900
740
670
905
905
905
560
620
770
560
625
670
795
.625
370
735
785
775
760
670
670
860
735
690
Note:  Bale volumes were determined by individually measuring each bale.   Bales
       were weighed in groups of four and averaged.  This average was used in
       determining density.
                                     19

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70
60
40
30
                                                 FIGURE 5
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                                               '  *>°
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20




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                                     10 i :
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                                                   F
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                                                       i:
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20
                                     4*
                                  «.i$
                                                       :4:
10
                              -Ji4.iit
                                                               i  i i

                                                             :I4|
                                         tin  ::::  :;[: I tri.1Jr4-M-thi
 300      400       500       600       700       800       900      1000


                            POUNDS  per  CUBIC YARD  ,p(, 20  jmb 3-68

-------
 refuse" was  highest at  7^7 pounds  to  the cubic yard, of those with "excessive
 garbage"  next at 700 pounds to  the cubic yard, and  of those with  "excessive
 paper" lowest at 656 pounds to  the cubic yard.  By  statistical  (standard error)
 analysis,  the probabilities that differences between these averages are sig-
 nificant  were found to  be  90 per cent as between  "San Diego refuse" and  exces-
 sive garbage," 99 per cent as between "San Diego  refuse" and "excessive paper,"
 and 95 per cent as between "excessive garbage" and  "excessive paper."  It is
 virtually certain, therefore, assuming that the judgments as to appropriate
 classification were accurate, that the superior eompactibility of "San Diego
 refuse" .as compared with "excessive paper" is significant and not due to
 chance.   The odds are nine to one  that it is also superior to "excessive gar-
 bage" in  eompactibility.

 It  was noted above that "typical San  Diego refuse"  constituted only about -one-
 fifth of  all of the solid  wastes processed during the test-  The reason that
 the composition of solid waste  materials processed  in the test was not repre-
 sentative  is probably that it was  conducted during  the Christmas season When
 the incidence of paper  in  the refuse  is higher than at other tiroes of the year.
 These considerations suggest that  if  the baling test program had been conducted
 throughout the year,  or at a more  representative  season, average densities
 would have been closer  to  the 7^7  pounds per cubic  yard found for "San Diego
 refuse" than to the 689 pounds  per cubic yard actually obtained in the test.

 Certain characteristics of the  bales  were evaluated by a member of the proj-
 ect staff, using a scale from 10 (excellent) to 0 (totally unsatisfactory).
 These appraisals are summarized in Table 2  on page 22.  "Shape of bales" and
 "fines retention" were  judged to be fair to good, and "handling ease," "liquid
 retention,"  and "odor absence"  were rated good to excellent.

 In  the later stages of  the test considerable pre-sorting of non-baleable mate-
 rials was  necessary.  A large number  of Christmas trees, received during the
 two weeks  following the holidays,  and also a number of other bulky or exces-
 sively long  items had to be  separated out manually because they could not be
 fed into the baler.   On some  days  these rejected materials constituted as much
 as  ten per cent of the  volume of the  refuse processed.  This difficulty would
be  minimized by hogging or shredding  the refuse ahead of the baling operation.

 Attempts to  determine the  effect on compaction of adding water to the refuse
 during the baling process  were  inconclusive.  It was found to be virtually
 impossible to apply water with  any degree of uniformity to raw,  unshredded
 refuse.  Densities  obtained during the first seven days of the test,  when no
water was  added,  were almost  identical to those obtained during the  next nine
days, when water was added.  A more significant factor appeared to be the
water content of  the refuse as  it arrived from the collection route.   If it
was relatively wet, as after rainfall, compaction was increased and  the shape
of  the bales was  improved.   The effect of adding water to the refuse  during
baling might well be the subject of future study under better controlled con-
 ditions .

 Two other serious problems  were encountered:   (l) tying the bale wires manu-
ally  was rather  time-consuming and constituted a real bottle-neck in  the opera-
tion  (this can probably be  cured by the development of a workable automatic
                                      21

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                                    Table 2
                  SUMMARY  OF RATINGS OF BALE CHARACTERISTICS
                              LOCAL BALER TEST
Judg-
ment
Scale
10
9
8
7
6
5
4
3
2
1
0
Total
S
Median
Q
Shape of
Bale
No.
0
18
44
46
24
10
13
4
1
0
2
162
8.5
7-6
6.4
JL_
0.0
11.1
27.2
28.4
14.8
6.2
8.0
2.5
.6
0.0
1.2
100.0


Handling
Ease
No.
3*
40
32
19
13
11
3
1
6
0
_3
162
9.8
8.8
7-2
_!_
21.0
24.6
19.8
11.7
8.0
•6.8
1.9
.6
3-7
0.0
1.9
100.0


Liquid
Retention
No.
58
28
24
8
2
0
0
0
0
0
	 0
120a
10.0
9-9
8.9
_i_
48.3
23.3
20.0
6.7
1.7
0.0
0.0
0.0
0.0
0.0
0.0
100.0


Fines
Retention
No.
10
31
44
33
13
16
9
2
1
0
_3
162
9.0
8.1
6.7
_1_
6.2
19.1
27.2
20.4
8.0
9.9
5-6
1.2
.6
0.0
1.8
100.0


Odor
Absence
No.
36
27
38
36
16
5
1
0
0
0
	 0
159*
9-9
8.6
7-5
_L_
22.7
17.0
23-9
22.7
10.0
3-1
.6
0.0
0.0
o.o
0.0
100.0


Note a - 42 bales were not judged on this characteristic,
     b -  3 bales were not judged on this characteristic,
                                     22

-------
 tying device)  and (2)  jams  due  to  "bridging" of the refuse as it was conveyed
 toward and fed into  the baler frequently caused stoppages and had to be broken
 UP "by positive manual  disloging of the material (this problem would be mini-
 mized by pre-shredding).

 After the conclusion of the initial phase of the baler testing program
 described above,  6k  additional  bales were produced and "nested" in a hillside
 shelf dug out  for tLis purpose. A fork lift was used to stack the bales to a
 height of three tiers. Approximately 55 cubic yards of baled refuse were dis-
 posed of in this  manner and covered with earth.  Voids between the bales were
 estimated at 15 per  cent  of their  aggregate volume, so that a total of approxi-
 mately 63 cubic yards  of  space  were required to accommodate the 55 cubic yards
 of refuse.   These voids resulted from the impossibility of nesting the bales
 as close together as desired, partly because of their somewhat uneven surfaces
 and partly because a fork lift  is  not an appropriate device for this purpose.
 To some extent the operator's view of his work is obstructed by the bale it-
 self.   Placing the bales  vertically from above would be more effective than
 moving them laterally  from  the  tines of a fork lift.  Future experiments may
 show  that a better machine  for  this purpose would be a crane of the clamshell
 type  but with  flat jaws.  Bales of higher compaction and consequently of better
 shape,  such as those produced with pre-shredded refuse at the American Baler
 Company's demonstration (see the next section of this chapter), could undoubt-
 edly be stacked more successfully.

 Pictures  of the disposal  experiment described above are shown in Plates 6  to
 9  on pages 24 to 27.

 Manufacturer's  Refuse  Baling Demonstration

 Early  in the course  of the  project, the staff sent a total of fifty letters of
 inquiry to  all known baler  manufacturers in this country as listed in MacRae's
 Blue Book.   Copies of  this  inquiry and the mailing list to which it was sent
 appear in Appendix 2 of this report.  The letter described the purpose and
 scope  of  the project,  requested brochures and information about the manufac-
 turer's baling equipment,  and invited comment and suggestions on the potential
 adaptability of such equipment  to  the baling of municipal refuse.   Twenty-five
 responses were  received.  Four companies were out of business or their forward-
 ing addresses were reported unknown.  Of the number responding,  ten do not
 manufacture any equipment suitable for baling municipal refuse at all and
 eleven manufacture only conventional balers designed for small applications
where  continuous, high-capacity production is not required,.   The remaining four
 appeared  to be promising in that they stated they planned to start or in some
 cases had already started to engineer and construct balers specifically
 designed  for use with municipal refuse.

Follow-up letters were sent to these four firms affirming our interest and
 suggesting meetings  to discuss the equipment they now have or plan to develop.
 In some cases these  invitations were reaffirmed by long distance telephone
calls.  Only one baler firm, the American Baler Company of Bellevue,  Ohio,
responded to the extent of sending representatives to discuss detailed possi-
bilities and problems.
                                      23

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                   VIEWS OF LOCAL  BALE DISPOSAL EXPERIMENT    FIGURE 6
  Hillside  before
  "being cut to
  create  simulated
  landfill
  .

•
             .

                 •
j
                                                          .
                                                        -*-

                                                                          .  •
                                                                                 -
                                                                                         -
                                                           Fill cutting jo'b
                                                           approaches completion
 Some of the bales
 are  dumped on  the
 ground for pick-up
 by the fork lift
This page is  reproduced at the
back of the report by a different
reproduction method  to  provide
better detail.
                                       24

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VIEWS  OF LOCAL BALE DISPOSAL EXPERIMENT
                                       Other bales  are
                                       transferred  directly
                                       from the  truck to
                                       the fork  lift
Fork lift stacks
the bales in the
simulated fill
                                      Stacked bales
                                      are covered
                                      with earth
                                       NOT REPRODUCIBLE
                       25

-------
      t
 f
 o
3 g
•P
       VIEW OF LOCAL BALE  DISPOSAL EXPERIMENT
                                                                                               Stacked bales

                                                                                               ewed from abovt
                                                                                                                   • .


-------
•so
m
T3
90
o
o
c:
O

CO
; j
•-j
                                         ' t     '-t'i   '
                                           '
         VIEWS OF LOCAL BALE  DISPOSAL EXPERIMENT
           ^SSrrtl&SL f.f      :•»''  .  *«*'
           £z£^&-:    -:.V-'  i   >^^tV- v
             •f§T'~- .-•'". ^ -Si*" x          A /  '

             j^>;"';.'^'""  <^'--



ftfiS^'..^! V ••i-^.,'^  \:j&t f-r1'*7-
•' /;   .i*:'-»*
  Si'.*. S*
                                                                                                        Front view of "bales
                                                                                                        "nested" in the fill
                                                                                                                                    N
                                                                                                                                   • M
                                                                                                                                    O


                                                                                                                                   . M

-------
-
                        m
            j.*             ««*
                            -  . AVt^^^^HHB^^S^^n*^
       FACTORY RT,?lr::- BAILING Df24CKSTRATICN


         .




                                                                           Shredded, materials are descending
                                                                           through baler hopper and bales are
                                                                           being compressed and extruded at
                                                                           left.  Note black spacer between bales,


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   FACTORY  REFUSE BALING DEMONSTRATION
I
                               t

A
                                                                      i
                                                                                    •

                                                                                                           ;. <••'',  *

                                                                                    '

                                                                                     !
                                                                                          Completed bale is emerging
                                                                                          from chamber

-------
 As  a result of these conversations,  this  firm offered to conduct, at  its own .
 plant and at its own expense,  preliminary tests  of  the feasibility of baling
 refuse.   This demonstration took place  on January 9> 1968.   It was witnessed
 by  San Diego's Project Coordinator,  by  the Reviewing Officer of the United
 States Public Health Service's Office of  Solid Wastes, co-sponsor of the proj-,
 ect described in this report,  and by other interested observers.  Appendix 3
 is  a verbatim copy of the company's  notes on this demonstration.

 The material baled in the Bellevue test was pre-shredded rather than raw
 refuse.   On the basis of  its long experience with designing  balers for a
 variety  of materials the  company is  convinced that  the baling of refuse can not
 be  accomplished effectively without  pre-shredding.  They believe that unless
 this is  done bale densities will be  lower,  it will  be Impossible to add neces-
 sary moisture to the materials with  any degree of uniformity, an excessive
 amount of fines will be lost,  more pre-sorting will be necessary^ an
-------
 perhaps five or six tons at Bellevue) and extended over a period of time, it
 established the consistent and sustained feasibility of baling refuse which
 may vary considerably in composition and moisture content from day to day and
 from one collection area to another.

 The average compaction obtained in the local test, 689 pounds per cubic yard,
 was only about half as much as would be required to match the approximately
 1,380 pounds per cubic yard obtainable by conventional landfill methods.  How-
 ever, densities exceeding that level were attained at Bellevue with modern,
 heavy-duty equipment.  Based on the compaction actually obtained in the factory
 test and allowing five per cent of volume for voids between bales in place in
 a landfill, the volume required per ton for baled refuse is 91 per cent of that
 required with conventional landfill methods.  If the greater density guaranteed
 by the company were reached (and the same allowance for voids made), the volume
' needed per ton would be 77 per cent of that required with conventional methods.
 It follows that the potential saving in fill life that is realizable by baling
 can be expected to fall between 9 and 23 per cent.

 The marked difference in bale densities obtained in the two tests - more than
 twice as great at the factory as in the local test - was primarily due to (1)
 the amount of pressure applied (approximately 140 as against approximately 20
 pounds to the square inch respectively), (2) the moisture content of the refuse,
 and (3) the pre-shredding of the material.   Pictorial evidence of the impor-
 tance of pre-shredding is shown in Plates 12 through 15 on pages 32 through 35.

 One of the important functions that could be served by a pilot baling transfer
 station such as that described in Chapter IV of this report would be a deter-
 mination, under controlled conditions, of the relative contributions of each
 of these three factors to the high densities attained at Bellevue^  A limited
 amount of experimental evidence has already been built up on the effect of the
 first two factors (pressure and moisture) on the compaction of refuse.   Den-
 sities obtained by increased compressive loads up to 100 pounds to the square
 inch were studied at Chandler, Arizona, as  early as 1954.2  Los Angeles County
 has conducted similar tests and arrived at  comparable findings.  Neither of
 these investigations involved baling directly, and both of them dealt with
 refuse that had not been pre-shredded.   The American Baler Company has assem-
 bled data on the relationship of pressure to density based on the baling demon-
 stration described above and also on some earlier tests made in 1963, applying
 pressures up to 760 pounds to the square inch to pre-shredded refuse, and has
 derived the parameter curves shown in Plate 16 on page 36..!  The curves in all
 of these studies show a characteristic pattern of continued but diminishing
 increments  of density as pressure is increased.   A point is eventually reached
 at which further application of energy is no longer economically feasible be-
'cause of the minimal improvement of density and because the strain such
 pressures impose upon the machine leads to  excessive maintenance costs.   Where
 this point  falls is still a matter of practical judgment rather than of
 scientific  determination because up to now  experience in the baling of  refuse
 has been extremely limited.   Evidence of the efficacy of increased moisture
     2Quoted  and  shown graphically  in  American  Public  Works Association.
     Municipal refuse disposal.  2d ed.   Chicago,  Public Administration
     Service, 1966.   p.  53-54.

                                        31

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                            	IPS

                           ' -JiIALS^  LOCAL  -'

-------
50
O
o
CO
 U3
        CCWPARISON  OF RAW MATERIALS,  LOCAL AND FACTORY TESTS
                                                                                              Refuse in shredded form was
                                                                                              used in the factory tests
                                                                                                                               M

                                                                                                                             !  G

-------
COMPARISON OF
FINISHED PRODUCT
                                                                                     These bales were produced
                                                                                     in San Diego's local test
                                                                                                                    H
                                                                                                                    O

-------
t)

50

O

O
CD
                                                                                                                                                                                                                   -
                                                                                                                                                                                                                  i-

                                                                                                                                                                                                                  §
                                                                                                                                                                                                                  pa
                                                                                                                                                                                                                  r

                                                                                                                                                                                                                  H
                                                                                                                                                                                                                  1  •

-------
                                                      FIGURE 16
0  TONS '  10    'PER  201    SQ.  '30   FT

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 content  in  improving  the  density  of  compressed  refuse was  found  in  the  compac-
 tion  tests  in  a  landfill  situation  (but  presumably  also  applicable  to baling).
 It was noted earlier  in this  chapter that  the American Baler  Company's  guarantee
 of high  density  with  their  equipment is  conditioned in part on a 30 per cent
 content  of  moisture in the  material.  Further study of the optimum  percentage of
 moisture is needed.

 The pre-shredding  of  refuse is  also  a condition of  the company's guarantee.
 It is felt  that  this  requirement  is  not  arbitrary or capricious.  It is based
 on the company's own  experience and  the  opinions of three  private firms now
 investigating  the  baling  of refuse who are convinced that  pre-shredding is
 essential for  the  reasons stated  in  the  preceding section  of  this chapter.  One
 of these firms,  the Southern  Railway Company, is reported  to  have estimated
 that shredding costs  will be  approximately 50 cents a ton.  This figure is con-
 sistent  with the findings of  preliminary cost studies made by the project staff
 in connection with its investigation of  the economic feasibility of baling
 transfer stations.  This  aspect of the project  is discussed in. Chapter  IV of
 this report.

 Summary  of  the Chapter

 Although the baling process has long  been  used  for  packaging  a wide variety of
 agricultural and industrial commodities, the concept of  applying it to  the
 solid waste field  is  relatively new  and  presents some technical  difficulties.

 The physical feasibility of this  application and the degree of compaction
 obtainable  by this method were  investigated by  actually baling refuse in an
 extensive local  test  (162 bales)  and  in  a  baler factory demonstration.  The
 findings  of the  two tests tended  to  corroborate each other.   In  the local test
 a large  quantity and  variety  of raw,  unprocessed refuse was successfully baled
 over a period of time, but  the  average density  obtained was slightly less than
 700 pounds  to the  cubic yard.   Although  the factory demonstration was more
 limited  in  scope,  the'four bales  that were produced averaged  about  1,500 pounds
 to the cubic yard  in  density  and were superior  in shape ard integrity.

 Densities obtained locally  are  not competitive with the approximately 1,380
 pounds to the cubic yard obtainable by our best landfill methods.   The  fact
 that compaction  obtained at the factory  exceeds that level is attributable to
 greater  pressure, high moisture content, and the pre-shredding of the material
 before it was baled.   The tests indicate that baling refuse not only is
 physically  and technically feasible but  also has great potential as a means
of conserving landfill space  in San Diego  and elsewhere.

-------
                                  CHAPTER IV

               ECONOMIC FEASIBILITY OF BALER TRANSFER STATIONS
 It was  established in Chapter  HI of this report that it  is  physically and
 technically feasible  to bale city-collected refuse with presently available
 baling  equipment.   It was  shown further that when this equipment has high
 compression capability and when the  refuse  materials  are pre-shredded,  it is
 possible  to obtain significantly  greater  compaction by this means than has
 been obtained by our  best  present landfill  methods.

 It is believed that the potential economic  benefits of baling refuse can be
 fully realized,  however, only  in  the operational setting of a transfer sta-
 tion.  It will be  shown in this chapter of  the report that a functional
 integration of the baling  and  transfer concepts  is the key J;o substantial
 savings when the exhaustion of favorably  located facilities requires longer
 direct  hauls by  collection vehicles  to a  more remote  landfill.

 The essential requirements of  the refuse  baling  process, as described  in
 Chapter IH>  virtually dictate that  it be performed at an intermediate point in
 the collection-disposal sequence.  To produce the degree of compaction neces-
 sary to prove out  economically the baling press  must  have high compression
 capability  and must therefore  be  heavy, massive,  and  stationary.  Since the
 most effective compaction  can  probably not be achieved without pre-shredding,
 another heavy piece of equipment  for this purpose is  also needed.  These
 technical requirements make impracticable,  at this time, some of the ideas
 that have occasionally been advanced:  (l) balers in residences and shops
 (so-called  point of origin processing analogous  to the garbage-grinding dis-
 posal units now  in widespread  use),   (2)  installation of baling devices in
 refuse  collection  vehicles, and  (3)  separate portable balers that might be
 transported from one  collection area  to another.

 The other possible  alternative  - placing  the baling operation at the landfill -
 reduces flexibility (the plant may not be well located for subsequent use when
 the fill  is completed)  and eliminates the possible savings that might be real-
 ized by the strategic  location  of a baling transfer station near the center
 of  a collection  area.   It  is axiomatic that to the extent that more time must
be  spent  in hauling refuse, as the distance increases between the area of
 origin  and  the point  of disposal,  less time is available for actual collec-
 tion.   Therefore, additional vehicles and crews must be placed in service to
 complete  the route.  Formulas developed by the project staff for determining
 the  number and cost of  such replacement vehicles are described in a subse-
 quent section of this chapter.

 Conventional Transfer Stations

 In an earlier period  of sanitation service  history, horse drawn wagons were
 used to collect  and haul refuse to the disposal  site.  In those times, this
 method  worked well for relatively short hauls.  Four miles was the usual
                                        38

-------
maximum distance beyond which it was more economical to use the transfer con-
cept.1    In early transfer operations, refuse was removed from the collection
wagons  at central locations and placed in larger wagons for re-haul to the
landfill.  The system had the advantages of decreasing the time, distance,
and cost  of hauling by collection vehicles and increasing the time available
for collection.

The motorized vehicles that replaced horse drawn wagons had sufficient speed
to overcome the problems of additional haul time.  The economics of direct
haul became more favorable and the advantages of transfer diminished or dis-
appeared.  As urban areas continued to expand, however, problems of additional
haul time began to reappear with increasing frequency as the distances between
collection areas and disposal sites increased.  This new cycle is resulting in
a revival of and economic justification for the old transfer idea, but in
terms of modern equipment and practices.

Although  there is considerable variation in the designs of individual trans-
fer stations now in use, the basic concept of removing refuse from collection
vehicles to supplementary transportation vehicles remains unchanged.  Most
conventional transfer stations can be categorized as either direct dump sta-
tions or  storage-type stations.2   In direct-dump stations, collection vehi-
cles at an upper level empty refuse into re-haul vehicles positioned at a
lower level.  In the transfer stations of this type operated by the Sanitation
Districts,  Los Angeles County and "by Orange County, California, a loader
equipped with a "clamshell" type bucket distributes solid waste materials in
the re-haul vehicle and effects some compaction by tamping the refuse.3   New
York City operates a water-side station where collection vehicles dump their
loads into barges which are then towed to the disposal site.4   Storage-type
stations  involve various methods of rehandling the material.  Cranes or der-
ricks are sometimes used for transferring an accumulation of dumped refuse to
the re-haul vehicles.  Another arrangement utilizes a conveyor belt and hopper
system.   "The material is dumped from the collection trucks into pits so
shaped that the refuse falls by gravity to the conveyor.  The hopper is con-
structed high enough to permit the transfer vehicles to drive underneath to
be loaded."'   In other variations of this type, workers pick salvageable
materials off a slowly moving conveyor belt or electromagnetic devices remove
the ferrous metals.
     1American Public Works Association.   Refuse collection practice.   3d ed.
      Chicago, Public Administration Service,  1966.   p.  203.

     2Ibid., pp. 213-215.

     3Pictures of the transfer station operated by the Sanitation Districts
      of Los Angeles County appear in Plate 17 on page 40.

     4Ibid., pp. 21U-215.

     5Ibid., p. 214.
                                        39

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               VIEWS  OF A CONVENTIONAL TRANSFER STATION     FIGURE 17
 Refuse vehicles
 weigh in at the
 scale house
                 They proceed to the
                 upper level of the
                 station
Loads are dumped
into re-haul vehicles
stationed below
   NOT REPRODUCIBLE
                 This loader is used
                 to  spread and tamp
                 refuse in the trailer

     (Courtesy of Sanitation Districts,
      Los Angeles County, California )
40

-------
The simplicity of the design of these transfer stations makes for easy,
expeditious operation with relatively few stoppages due to equipment failure.
They have the disadvantage that in the transfer process much of the compac-
tion obtained in modern collection vehicles is lost due to fluffing and
spring-back of the materials when they are extruded from the packers.  Greater
volume per unit of weight is thus required in the re-haul vehicles than would
be needed if the refuse had the same density as in the packer truck.  For this
reason it is usually necessary to use both a semi-trailer and a full trailer
in order to haul efficiently with tonnages approaching legal load limits, thus
increasing costs and reducing maneuverability.  This is a major inherent weak-
ness and it can be eliminated only by introducing into the transfer station
some more effective form of compaction process than simple temping.      i

The net savings realizable by conventional transfer stations are limited to
those related to collection and haul costs.  Operations at the disposal site
receive  no direct economic benefit.  The compacting methods that must be used
there are identical whether the refuse is received from re-haul vehicles or
from packer trucks.  The incorporation of baling in the transf&r station oper-
ation, on the other hand, is a promising means of realizing additional net
savings not only by effecting significant reductions in disposal costs but by
reducing the number of trailers needed for re-haul.  With baling, the legal
load can be carried in one trailer instead of two.

The Proposed Pilot Baling Transfer Station

A pilot baling transfer station is needed (l) to test the baling process
under actual production conditions,  (2) to refine baling techniques and
routines,  (3) to compare the compaction obtainable with pre-shredded versus
unprocessed refuse,  (k) to ascertain the optimum moisture content of the
refuse being baled,  (5) to determine and deal with any possible nuisance fac-
tors or health hazards (such as noise, dust,  odor, and vector breeding) that
may be encountered in the operation,  (6) to develop effective practices in
placing the bales in a landfill,  (7) to explore the feasibility of other
means of bale disposal, such as in the reclamation of small canyons near
residential areas, and  (8) to develop accurate cost comparison under actual
operating conditions.

Certain preliminary comments are necessary,  however,  before the pilot baling
transfer station which has been proposed to serve these purposes is described.
The fact that the proposed station is a prototype has a number of specific
implications:

    A.  Since some of the mechanical procedures involved have not been vali-
        dated for the purposes contemplated,  the station layout described in
        this chapter was based on the design theory of staff engineers and
        the opinions of consultants familiar with the individual items of
        mechanical equipment.
                                       41

-------
     B.   The designs and sketches presented herein describe  a pilot "baling
         transfer station rather than a full-scale plant.  This  j,s the prudent
         approach to any new operational procedure,  however  promising, that
         involves a substantial capital outlay.   In previous experience, baling
         municipal refuse (as discussed in Chapter III)  has  been experimental in
         nature and limited in scope.  It should be thoroughly tested and
         evaluated on a reasonably large scale under actual  operational condi-
         tions.  Because of its specialized purpose and  smaller  capacity,  how-
         ever,  a pilot plant is somewhat at a disadvantage in economic compari-
         sons with (l) present methods of landfill operations (because it  would
         disrupt present large-scale  operations),   (2) a conventional transfer
         station, and  (3) a full-scale baling transfer  station.

     C.   The pilot station design should be realistic.   It should include  not
         only «O1 of the basic essential elements  but also,  if possible, some
         of  the desirable features that will - if  the pilot  operation is
         successful - be incorporated in a subsequent full-scale  plant.  The
         purpose is to reduce labor cost,  which  in any such  undertaking consti-
         tutes  the major portion of estimated annual expenditures, and to  mini-
         mize possible problems that  might be associated with human error
         during the operation.

In general,  the refuse baling transfer station  differs  from the  conventional
transfer station in three distinctive respects:   (l) the presence of special-
ized processing equipment,   (2)  a more sophisticated system of conveying  the
materials from one stage to the  next,  and  (3)  the  state of the  refuse at the
completion  of  the operation.

A plan drawing of the proposed pilot baling station, which would be capable of
processing  150 tons  of refuse a  day, appears in^ Plate is on page 43   and eleva-
tions are shown in Plates  19  and 20  on pages 44  and 45 .  As designed, the
functional  point of  refuse  entry into  the  actual plant  operation is a dumping
pit  large enough to  accept  up to four  packer trucks at  a time which will also
serve as temporary storage  space for up to 100  cubic yards of refuse.  Two
belt type conveyors  in the bottom of the pit, each four feet wide, transport
the  refuse  into the  plant.   Since these belts are designed to "be operated
independently  and at either  simultaneous or differing speeds by remote con-
trol within the station, they can be manipulated to break up bridging of
refuse that might  occur  in the storage  pit.  For purposes of safety,  hand-
operated trip mechanisms would also be  installed at strategic locations.

At the inbound  ends  of  the twin belt conveyors,  refuse is fed into a rectan- .
gular hopper leading to the hogger (shredder) for the first phase of  refuse
processing.  Immediately above the hopper near the ends of the pit belt con-
veyors, a separate breakdown conveyor operates to expedite and meter the flow
of refuse into  the hopper  (see Plate 19 on page 44). It is expected that this
device will tend to  feed refuse  into the hogger at a uniform rate and prevent
surges in the operation.
                                        42

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                                                         1 FIGURE 18
                Roller   conveyor
Belt  conveyor
(baler feed)
Twin  belt or roller conveyors for  plant storage
                  (12  bales)

           Loading   dock


Verticol  conveyor


            Subterrean  hogger  room

             Hogger



           oth  of   packers	.---


            Dump  this  side  only

                     62'
                                 Dumping   pit

                                -Twin  belt  conveyors  alternate use.
                                pathof
                                                                  •o
                                                                   o
                                                                   o
                   Emergency
                     dump
                     or ea
                                 Scale  l" =  20'



  PILOT    REFUSE    BALING    TRANSFER     STATION

               Design    Capacity   150 tons/day
                            43

-------
            Enclosed
             belt  conveyor
                 B
      Baler  hopper-,1
grd.  line
xVerticol
  bucket
   conveyor
                                                                                C conveyor    belt
                                                                                                       PIT
                                                                                 sump
                                                                                                                 I
                                                                                                 I" = 10'
                             ELEVATIONS    OF    PILOT    BALING   STATION

                                              Sheet  I   of  2
   jmb 2-20-68

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 RoMer   conveyer  or  trai'le/
 I—{—j   1  I   with  roller  bed
 Bojles;   j  J     	_J
                                 —Same  point
                                       at  90°
 roller
, convey or-g
                                                                         B
                                                                                Bucket  conveyor
                                                                              Belt  conveyor
                                                                             • Baler hopper
Ba ler
                                                                         B
                                                                                           HKtttff
                  ELEVATIONS    OF    PILOT    BALING   STATION

                                     Sheet   2  ot  2
                                                                                      I"  =  10'

jmb  2-20-68

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 The subterranean location of the concrete building housing the hogger and its
 hopper has the advantage of tending to contain dust and "fly" refuse from the
 hogger and to suppress the noise of the operation.

 After being processed through the hogger the refuse materials, now in frag-
 ments no larger than from four to six inches, fall onto a belt typeiconveyor,
 are transported^ to an enclosed vertical bucket type conveyor, elevated therein
 to a height of fifty feet, fall onto another short belt conveyor, and finally
 drop into the baler hopper for the second phase of processing (see Plate 20
j on page 45).

 The baling press, housed in an enclosed structure to permit operation during
 inclement weather, produces uniform bales at an estimated potential rate of
 one every three minutes.   Experience in this field shows that this interval is
 long enough for two men |to hand-tie the bales (if automatic tying devices
 become available some of this labor cost could be saved).   The bales emerge
 from the press onto a roller conveyor and are then mechanically pushed 90
 degrees onto  twin roller conveyors.  They move on these to the end of the
 loading dock  and directly onto the re-haul vehicle, the bed of which is it-
 self equipped with rollers.   This vehicle (a semi-trailer) is positioned on an
 incline, so that the bales roll into place by the force of gravity.  As soon
 as one vehicle is fully loaded and departs for the disposal site, another is
 parked at the dock and the loading process continues.

 Cost of the Proposed Pilot Station                              !

 It is estimated that the  proposed pilot baling .transfer station described in
 the preceding section of  this chapter can be built on  city owned land and
 completely equipped, including the hogger, baler and all necessary appurte-
 nances, for $201,000.   An itemized breakdown of  capital investment costs is
 presented in  Table 3 on page 47.

 Estimated current operating  costs for one year,  totaling $127,200, are given
 in Table 4 on page 48.  The  estimated cost of hauling  completed bales to the
 landfill is shown as part of plant expense,  and  the cost of equipment and
 labor for the actual disposal of  the bales at the fill is  shown separately.
 Because of the specialized,  evaluative purpose of the  pilot plant and its
 presumably short  life expectancy, computation of annual costs of amortization
 would not be  appropriate.

                Conventional  versus Baling Transfer Stations

 Conventional  Transfer Station

 The chief advantages of a conventional transfer  station are:   (1)  it  is  rela-
 tively easy to plan and construct,  (2)  its basic operating procedures are
 simple and direct,  (3)  it can accept a wide  variety of refuse materials  in- .
 eluding certain problem items that normally  can  not be shredded or baled,  (4)
 transfer of the refuse  is accomplished quickly,  and (5)  the absence of  com-
 plex machinery minimizes  the possibility  of  a complete station shutdown  due  to
 equipment failure.
                                      46

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                              TABLE 3

   ESTIMATED CAPITAL EXPENDITURES FOR PILOT BALING TRANSFER STATION
1.
2.
4.
  Item

Site Preparation
    Site Grading
    Paving  (8,000 sq. ft.)
        Contingencies
Dumping Pit
    Structural Excavation
    Concrete Pit (34 cu. yd.)
    Hardware
    Pit Conveyors w/motors
        Contingencies
                                                   Amount
                                                  $    500
                                                     2,88C
                                                       320
                                    Sub-total        5,800
                                                       30C
                                                     4,000
                                                     3,000
                                                    28,000
                                                     3,500
                                    Sub-total     $ 38,300
Hogger Pit Building
    Concrete Building
    Structural Excavation and Backfill
    Breakdown Conveyors (2)
    Hammer Mill
    Coupler, Hopper, Motor and Starter
        for Hammer Mill
    Bucket Conveyor for 50' Lift
    Sump Pump and Drain Line
    Air Blower with Conduit
    Ladder
    Lighting
    10$ Contingencies*
                                Sub-total

Baler Building
    525 sq. ft. Building
    Earthwork
    Truck Dock 340 sq. ft.
    Baler
    10' Belt Conveyor
    60' Roller Conveyor
    Lighting
    Electrical Service and Power Panel
    Water Service (by City Forces)
    10$ Contingencies*
                                Sub-total
                                                  $  8, ooo
                                                       800
                                                     3,000
                                                    32,000

                                                    21,475
                                                    10,000
                                                     1,500
                                                     1,000
                                                       450
                                                     1,000
                                                     2,575
                                                  $ 81,800
                                                  $  5,250
                                                       600
                                                     2,800
                                                    35,500
                                                     2,000
                                                     6,000
                                                     1,000
                                                    18,000
                                                     1,800
                                                     3,750
                                                  $ 7b,700

                     TOTAL CAPITAL INVESTMENT     $201,100
    Contingencies not computed on heavy machinery.

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                               TABLE 4

                  ESTIMATED CURRENT OPERATING\]XPENSES

             OF PILOT BALING TRANSFER STATION FOR ONE YEAS
    Item

Plant Operation Costs

1.  Re-haul equipment                                          $ 15,$60

2.  Plant Labor
        2 heavy truck drivers                    $  17,7^0
        1 utility foreman                           10,26?
        2 laborers                                  15,322     $ ^3,329

3.  Maintenance and repair                                        6,^76

k.  Electrical power and water costs                              7,000

5.  Bale ties and supplies                                       10,000



Bale Disposal Costs

1.  Crane rental                                                10,200

2.  Labor (equipment operator and laborer)                      15,^50

3.  Bulldozer for covering (l,000 hrs @ $lVhr)                  14,000

U.  Bulldozer operator (1,000 hrs)                               5,185

              TOTAL ANNUAL OPERATING COSTS                   $127,200
                                 48

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 As  compared  with  a full-scale baling  transfer station,  the  disadvantages  asso-
 ciated  with  the conventional  station  include:   (1)  higher station total opera-
 ting  costs  (including  re-haul costs),   (2)  larger  land  area required,   (3)  loss
 of  much of  the  compaction obtained  in the collection packer truck,   (4) larger
 number  of re-haul vehicles for comparable tonnages  of refuse transferred, and
 (5) higher  cost of disposing  of raw refuse  at the  landfill  (see Table  9   on
 page  6.4).

 Baling  Transfer Station

 In  the  main,  the  disadvantages and  advantages  of the baling transfer station
 are the converse  of  those set forth above.  Disadvantages of the  baling trans-
 fer station  include:   (1)  more difficult to plan and construct,   (2) greater
 complexity  in operating procedures,   (3) greater vulnerability to stoppages
 due to  equipment  failure,   (4)  slower  process  at transfer station although
 offset  by less  time  required  at fill  site,  (5) greater possibility of public
 objection to  the  noise of  the machinery, and   (6) the character of the refuse
 must  be controlled due to  technical limitations of  the hogger.6

 As  compared with  the conventional transfer station,  the baling transfer sta-
 tion  offers  the advantages of:   (1) lower annual operating  costs  (including re-
 haul  costs),  (2)  smaller  land  area required,   (3)  fewer re-haul  vehicles needed,
 (4) lower cost  of  disposing of  bales at the landfill, as compared to raw refuse,
 (5) extension of  fill  life through  greater compaction, and   (6) utility of  refuse
 in baled form for  constructive  purposes such as small canyon reclamation.7

 Transfer Station Location

 Regardless of type, the transfer station "should:   (1) be located as near as
 possible to the center of  production of the collection area which it serves,
 (2) be  convenient  to the secondary  or  supplementary means of  transportation,
 (3) be  so placed that  there will be a minimum of public objection to the
 transfer operations, and   (4) be located at points where the  construction and
 operation will be most economical."8

These and other criteria for  the choice of a location for a  transfer station
 are set forth in Table 5   on  page 50 which was developed by the project staff.
These considerations are chiefly oriented to permanent,  full-scale stations
   6 For this reason, the proposed pilot baling transfer station would process
    only city-collected refuse.  Installing heavier-duty hoggers in subse-
    quent full-scale stations might permit acceptance of privately transported
    materials which, although they are more heterogeneous in character, con-
    stitute 60 per cent of the city's refuse.  In any case, convenient close-
    in landfills would be available to such private transporters for a longer
    period because of the extended fill life resulting from baling city-
    collected refuse.

   7 As pointed out in Chapter I,  San Diego has many such canyons which can be
    surveyed and evaluated for conversion by this means into useful and
    attractive park and recreational areas.  See Chapter V   for a discussion
    of small canyon reclamation.
   8 Ibid.,  p.  210
                                       4-9

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                                  TABLE 5

           FACTORS FOR CONSIDERATION IN LOCATION OF TRANSFER STATIONS

I.  GENERAL LOCALE OF SITE(s)

    A.  Proximity to theoretical center of the collection areaa served.
    B.  Proximity to population movements as they affect collection areas.
        1.  Probability of present routes served being reduced.
        2.  Probability of new collection routes being added to the transfer
            operation.
        3.  Location of future transfer stations.
    C.  Character of the area in relation to possible public objection to a
        transfer station.
        1.  Residential development.                                         ,
        2.  Commercial development.
        3.  Industrial development.
        k.  Miscellaneous (recreational,  hospitals, etc.)
    D.  Accessibility from collection routes and availability of exit routes for
        re-haul vehicles.
        1.  Expressways.
        2.  Major and minor streets.
    E.  Present and possible zoning ordinances governing Iwid use in the  area
        (to avoid conflict).

II. SPECIFIC AREA OF SITE(S)

    A.  Location should be at points where the construction and operation will
        be most economical.
        1.  Capital outlay for land.
        2.  Site preparation needed before construction.
        3.  Proximity to utility services  (e.g.,  gas,  power,  water,  etc.).
    B.  Character of area (zoning) bordering site in relation to possible
        public objection.
    C.  Accessibility to the specific site.
        1.  Major and minor streets  (e.g.,  street widths,  pavement thickness,
            traffic).
    D.  Zoning ordinance governing land usage at  the site.
    E.  Specific characteristics of  site.
        1.  Spacial dimensions.
        2.  Existing structures.
        3.  Other improvements.
    F.  Proximity to supplementary means of transportation.
        1.  Water-ways.
        2.  Railroads.
                                      50

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    THREE VIEWS OF A SMALL CANYON PROPOSED FOR RECLAMATION
       FIGURE  21
                                                         This canyon  is  too small
                                                         and too near a  residen-
                                                         tial area for a conven-
                                                         tional fill  operation
But it could be box-cut
and filled with nested
bales of refuse and
covered with earth
                                        51
                                                        Making possible  a valuable
                                                        extension of a city golf
                                                        course's present cramped
                                                        parking lot
hi Pf?u is rePr°duced at the
back of the report by a different
reproduction  method to pro-ide
better detail.

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 rather than pilot  stations  which by  definition  are  temporary  arrangements
 designed primarily for  evaluation rather  than for production  purposes.   The
 criteria for the selection  of  a site for  the  proposed  pilot baling  transfer
 station that appear to  be most relevant  to  this testing  and validation  func-
 tion  are:   (1)  avoidance of land costs by location  on  property  presently owned
 by  the city, (2) minimal site  preparation,  (3)  suitability'of site  for
 construction,  (4)  proximity to existing utility services,  (5) possibility  of
 obtaining  adequate supply of refuse  materials without  undue disruption  of
 regular collection routes and  routines,  (6) ease of access, and (7) prox-
 imity to a Small canyon which  can be filled with bales for reclamation  pur-
 poses.   Plate  21 on page 51 shows a  canyon  that could  be used for this  pur-
 pose.   The possibility  of future expansion of the pilot station into a  full-
 scale station was  not overlooked, but this was  not  a major factor in site
 selection.

 Two areas  were  considered for  the location of the proposed pilot baling trans-
 fer station:   (1)  the general  area of San Diego known  as Old  Town and (2)  the
 specific area within the boundaries  of the city's Central Operations Station
 at 20th and  B  Streets.

 The Old Town area  is strategically located not  only in relation to  the  Cen-
 tral  collection  district now served  by the Arizona  landfill (approximately 50
 per cent of  the  district's  collection mileage is in that area)  but  also' in
 relation to  some of  the Rose Canyon  operations  district now served  by the
 Miramar landfill.   In field surveys  of the area several possible sites  were
 identified and  evaluated.   The  project staff  concluded, however, that in the
 light  of the criteria described  above, this locale  is  probably  better situ-
 ated  for a possible  future  full-scale baling  transfer  station than  for  a
 pilot  station.

 The specific site, selected on  city-owned property  at  the Central Operations
 Station, is  pictured in Plate 22  on  page 53.  Located  at the  foot of a  steep
 earth bank to  the  east,  this site would not be  visible from residential area
 or from a  municipal  golf course  to the north.   Its  visibility from  a Naval
 hospital located about  a third of  a mile away and at a higher elevation might
 require landscape  screening.  It  will be recalled that'the suppression  of
 noise was  one of the important considerations in the design of  the  station.

 Access  to  the proposed  site is excellent.  Three major highways  radiating
 through  heavily populated areas of the city converge near the operations sta-
 tion.   Access to the specific site is by a road within the station.   Proximity
 to the  Arizona landfill would permit  easy re-routing of collection vehicles
 in the  event of emergency breakdowns  at the pilot plant.   Existing water,
 sewer,  and power lines  are  nearby, while lavatories and shower facilities are
within  easy walking  distance.
                                      52

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 U)
3
  f
H
3 *9 2
        Aerial view of small canyon proposed
        for reclamation (upper arrow) and
        proposed site for pilot station at the
        Central Operations Center (lower arrow)
                                                                                                                               o
                                                                                                                               3
                                                                                                                               M
                                                                                                                               tv
                                                                                                                               K)

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 These advantages,  together with the site's  proximity  to  a  small  canyon which
 could be filled with baled refuse as a model reclamation project -(perhaps
 leading to further exploitation of this idea in  the future),  appear  to make
 this  location the  best and most economical  choice as  a site for  the  proposed
 pilot baling transfer station.

 Basis for the Economic Feasibility Study

 Actual experience  with a pilot  baling transfer station would  undoubtedly con-
 tribute to a better appraisal of the economic feasibility  of  a full-scale bal-
 ing transfer station operation  than is now  possible.   Nevertheless it is
 prudent to make the best possible estimate,  on the basis of information
 presently available, of the cost of this approach to  a refuse disposal prob-
 lem that is becoming critical in San Diego  and elsewhere,  as  compared with
 other available alternative solutions.   For  a municipality that  is committed
 to the landfill method of refuse disposal,  the basic  alternatives are either
 longer direct hauls to more remote landfills  or  the operation of transfer sta-
 tions with or without an element of refuse processing, such as baling.  The
 refuse baling process is technically feasible and can produce greater compac-
 tion  than normal landfill methods.   In combination with  the'transfer concept
 it appears to offer great promise of substantial  savings.  It would be futile,
 however,  to make the necessarily large investment in  such  a system if careful
 and objective preliminary analysis  revealed  that  savings could not actually
 be realized in a specific situation.

 The economic feasibility analysis  described  in the remainder  DJ:  this chapter
 was based on data  derived from  a study of this city's  Central Operations Sta-
 tion  at 20th and B Streets.  This  location was chosen  for  this purpose prima-
 rily  for three reasons:   (1) its collection  area  is probably  comparable to
 those of the typical American city,  (2)  it produces substantially larger
 tonnages  of city-collected refuse  than do either  of the  other two major col-
 lection areas,  (3)  the exhaustion  of its Arizona  landfill, situated as it is
 in the heart of the city,  will  present  a more critical and costly situation
 than  will the completion of  the other  existing or available landfills.  In
 the course of the  study,  although  it was based on localized data, certain
 generalized concepts  and techniques  were developed which can  be  used to
 advantage in future investigations  of  this kind here and elsewhere.  Esti-
 mated comparative  costs  were determined  for  (1) longer direct haul to the
 disposal  site,  (2)  conventional transfer station  operation, and  (3) baling
 transfer  station operation.

 Data  for  Direct Haul  Cost  Study

 It will be  recalled  that  the present  collection fleet at the  Central Operations
 Station  consists of  twenty-three packer  trucks having twenty  cubic yard capacities
 and three-man crews  each  and one sixteen-yard, three-man packer  truck which oper-
 ates  in  the beach  areas.   At its other  two operations stations the city has replaced
 all twenty-yard, three-man packers with twenty-five-yard, two-man trucks and plans
 to do  so  at  the Central  Station within a few years.  The sixteen-yard vehicle will
 remain  in  service because  of the restricted street widths in  the beach areas.
 For purposes  of this  study it is assumed that these larger capacity vehicles will
be in  operation by  the time a full-scale baling transfer station could be con-
 structed  and  put into operation.


                                       54

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 The factors  which determine  the  cost  of  direct haul are:   (l) the average
 hourly cost  of  operating,  staffing, and  supervising each collection packer,
 (2) the average amount of  refuse transported per packer during direct haul,
 (3) the average mileage traveled per  packer in the direct  haul,  (4) the aver-
 age round trip  speed of a  packer while hauling, and   (5) the average time it
 takes  to complete the direct haul and return to the collection route.

 Hourly Cost

 As  computed  by  the Equipment Division of the Public  Works Department, cost of
 operating a  collection vehicle reflects  depreciation, overhead, repairs, tow
 calls,  minor modifications,  painting, fuel, overtime pay when necessary, and
 standby packer  trucks as needed.  Normally shown as per mile unit charges in
 the city's cost accounting practice,  these costs were converted to charges per
 hour for purposes of  this study.   The  average equipment cost of operating a
 twenty-five  cubic yard packer truck for  one hour was found to be $4.64.

 San Diego's  Sanitation Division  has three classifications  of collection per-
 sonnel:   Crewmen I,  II,  and  III.  All of these classifications perform col-
 lection duties  but only Crewmen  II and III are authorized  to drive packer
 trucks.    Therefore,  in the  twenty-five  cubic yard, two-man crew arrangement,
 in  which the men alternate in collecting and driving, only Crewmen II and III
 are assigned..  To obtain the present  average hourly labor  cost, it was neces-
 sary to determine the average pay steps  that Crewmen II and III have actually
 reached.   Average hourly base pay rates  at these points were found to be $4.4y
 and $4.72 respectively,  including fringe benefits.

 The hourly cost of collection supervision at the foreman level was found to be
 $ 0.82  per packer including  fringe benefits.

 Based on these  elements, the total hourly cost of operating a packer truck may
 be  summarized as  follows:

                 Item                                 Hourly Cost

        Equipment -  25-yard  packer                      $ 4.64

         Labor - Crewmen  II and III, including
                fringe benefits

        Supervision  - foreman level, per packer

                              Total

Average Mileage and Tonnage

Average mileage traveled per packer during direct haul is the quotient of the
total mileage traveled by all packers divided by the number of packers opera-
ting.  Since the present fleet of twenty-yard, three-man crew packers will be
replaced by twenty-five-yard, two-man crew trucks at the Central Operations
 Station, it was necessary to determine the number of the larger vehicles that
would be needed to replace the present fleet.   Records show that at the Cen-
tral Station the average amount of refuse collected and hauled is approximately
fourteen tons per day per packer, normally requiring three trips to the land-


                                      55

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 fill (occasionally four  trips are necessary when the refuse contains large
 proportions  of bulky items which occupy more volume in the packer).  The
 average  load on  the  basis of fourteen tons and three trips is U.65 tons per
 packer.   On  the  other hand, study of  collection records at the Chollas Opera-
 tions Station showed that on the average a twenty-five-yard packer transports
 6.5  to 7 tons of refuse  per trip.  This average has been increasing and
 Sanitation officials feel that ultimately 7«5 "tons per packer can be reached.
 For  purposes of  determining the tonnage transported during direct haul with
 the  twenty-five-yard packer, it is assumed that seven tons per load is a good
 average  and  that the amount of refuse collected per truck per day could vary
 between  thirteen and fifteen tons.  On this basis, the twenty-yard packers at
 the  Central  Station  can  be replaced with twenty-five-yard packers on a one-to-
 one  basis.

 In order to  obtain the total round trip mileage to be traveled during future
 direct haul,  it  was  necessary to determine the mileages between individual
 collection routes  and the proposed Murphy-Shepherd landfill to which it is
 assumed  Central  Station  packers would haul at the completion of the Arizona
 landfill in  1975-  For this purpose the approximate center (centroid) of each
 route and the most direct haul route  from that point to the landfill were
 determined.   Mileages  were found by map measurements, checked by driving the
 route by automobile.   Combined daily  and weekly mileages were computed for
 the  entire fleet.  A similar procedure was used to establish the round trip
 mileage  for  present  direct haul to the Arizona landfill.  The difference in
 mileage  between  the  haul to the proposed Murphy-Shepherd site and that to the
 Arizona  landfill is  the  base from which the additional cost of longer direct
 haul was calculated  (see Table 6.  on  page 57 for a summary of these mileages).
 The  average  mileage  increase in the round trip to the more remote landfill was
 found to be  9-9  miles  per packer.9

 Average  Speed and  Haul Time

 As part  of a  three-week  study to determine the average speed of a packer dur-
 ing  direct haul,  collection crews reported time and odometer readings for
 (l)  departure from the collection route,   (2) arrival at the landfill,   (3)
 departure from the landfill,  and  (h) arrival at the collection route.   The
 complete round trip was  recorded to take into account the difference in speed
between a loaded and an  empty packer.  Average speed during a complete  round
 trip was found to "be twenty-two miles an hour.

Average increase in haul time  per packer for one round trip to the proposed
Murphy-Shepherd landfill was  found to be twenty-seven minutes (by dividing
 the average round trip increase of 9-9 miles by the average packer speed of
 twenty-two miles  an hour and multiplying this quotient by sixty minutes).
     9The project staff's studies showed that,  in the specific  San Diego
      situation examined, the break-even extra  distance at which the  costs
      of direct haul and of a full-scale baling transfer station would be
      equal was about  10.1 miles.

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                                                  TABLE 6

                                     WEEKLY ROUNDTRIP MILEAGE INCREASE
                      DIRECT HAUL TO MURPHY-SHEPHERD LANDFILL VERSUS ARIZONA LANDFILL
Route
Col-
lection
Day
Mon.
Tues.
Tues.
Tues.
Wed.
Wed.
Wed.
Thurs.
Thurs.
Thurs.
Pri.
Fri.
Fri.
Number
of
Route Packers ,
Collected Required
LA PLAYA
OCEAN BEACH
LOMA PORTAL
OLD TOWN
SO. CENTER CITY
SOUTH PARK
WEST LOGAN HTS.
HILLCREST
WEST NO. PARK
MIDDLETOWN
NO. NORMAL HTS.
SO. NORMAL HTS.
EAST NO. PARK
Ik
6
1
8
8
8
6
9
7
6
8
7
6
100
Mileage
to
Murphy-
Shepherd
26.0
25-4
23-8
17.6
21.2
19-2
20.2
I6.lt
13.6
23.0
11.0
12A
12.8
Mileage
to
Arizona
16.8
19.8
15.0
9.2
6.8
4.6
8.6
5.6
k.O
9.4
6.6
5.4
3.2
Total
Mileage to
Murphy- d
Shepherd
364.0
152.4
166.6
140.8
169.6
153-6
121.2
147.6
95-2
138.0
88.0
86.8
88.8
1912.6
Total
Mileage
to d
Arizona
235.2
118.8
105.0
73-6
54.4
36.8
51.6
51-3
28.7
56.4
53-6
37-8
19.2
922.4
Total Mileage
Increase to
Murphy-Shepherd
128.8
33.6
61.6
67.2
115.2
116.8
69.6
96.3
66.5
81.6
3^.2
49.0
69.6
990. 2e
a.  Four of the station's twenty-four trucks (including the 16  cubic  yard packer)  have special schedules
    that vary from day-to-day during the week,  but this does not  appreciably affect the mileage figures.
b.  Twenty-five cubic yard vehicle.
c.  One round trip, collection route to landfill and return to  route.
d.  Number of packers times mileage for one round trip.
e.  Average increase per packer:  990.2 7 100 = 9«9 miles.

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 The Economics  of  Direct  Haul

 In standard practice,  estimates  of the cost of transporting quantities of
 materials  have been based on unit costs calculated from actual experience.
 These  units are usually  expressed as cost per ton mile if the emphasis is on
 the distance to be  traveled or as cost per ton  minute if the duration of the
 trip is  of primary  importance.   The distance basis is the older and more
 common concept and  is  suitable for use when conditions of travel are rela-
 tively uniform and  constant.  Under modern urban travel conditions encountered
 in transporting municipal refuse in trucks, however, the time concept is more
 appropriate.   Travel to  and from the disposal site may be on fast expressways,
 on congested city streets,  or on a combination of both.  It. is quite conceiv-
 able that  the  travel time of a refuse truck from a distant collection area to
 the landfill could  be  less,  if the route is on an expressway, than that of a
 packer hauling from a  closer area over city streets.  Moreover., all or most
 of the expense of operating refuse vehicles, consisting largely of labor costs,
 is normally accounted  for on a time basis or can readily be converted to it.

 The standard method of computing cost per ton minute is to divide the average
 total  hourly cost of operating the vehicle by the average payload in tons and
 to convert this quotient (cost per ton hour) into minutes by dividing by
 sixty.

 Cost estimates based   on the ton minute unit (or on the ton mile unit) are
 valid  only in  static situations  where changes in haul time (or distance) are
 not involved.  Gross errors result when this approach is used, as it some-
 times  has  been, to  estimate the  cost of the additional direct haul time (or
 distance)  required  by  the  closing of a favorably situated landfill and the
 consequent necessity of  transporting to a more remote location.  This common
 fallacy arises from attempting to apply to a changing situation a cost unit
 that is inherently  a constant, and overlooking the fact that the extra time
 spent  on the longer haul occurs  at the expense of time available for route
 collection.

 This point  can be illustrated by a local example based on the data contained
 in the preceding  section of this chapter:   the situation that will exist when
 the Arizona landfill is  completed and longer direct haul to the proposed
Murphy-Shepherd landfill "becomes necessary.

 In this illustration,   the basic  starting point is the following "standard"
 allocation  of  time during the working day of the collection forces:

                3*4-0  minutes for actual collection (productive)

                 80  minutes for hauling (subsidiary)

                 60  minutes for early morning preparation,  driving to
                     the route,  lunch and rest breaks,  and return to the
                	  station (subsidiary)

                     minutes or eight hours
                                      58

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During the actual productive time of 3^0 minutes the packer crew now collects
an average of fourteen tons of refuse.  The collection rate is therefore 2^.3
minutes per ton  (3*1-0 minutes divided by Ik tons) and the total daily weight
of refuse collected by a fleet of twenty-four packers is 336 tons.  In the
new  conditions imposed by the closing of the Arizona landfill, however, each
round trip haul would increase in distance by 9«9 miles and, in time required,
by twenty-seven minutes.  With two such trips a day, the total time lost would
be fifty-four minutes, and the time available for collection would drop from
3^0  to 286 minutes (assuming that time for preparation and rest breaks would
remain constant).

At the collection rate of 24.3 minutes per ton, a packer crew would now col-
lect only 11.8 tons per day and the fleet would collect 283 tons per day
instead of the normal 336 tons.  The deficit of fifty-three tons which could
not  be collected in the time available would require either that the crews
work overtime or that additional packers and crews be placed in service.
Since a policy of requiring continual overtime work (in effect a permanent
lengthening of the working day) would not be a practical alternative, an
enlargement of the fleet would be required.

In these circumstances the number of additional packers required depends on
the  tonnage to be collected and the daily rate of collection per packer.  In
the  example being considered, the addition of U.5 packers to the fleet would
be needed (53 tons divided "by 11.8 tons daily rate) or actually, since the
operation of half a truck would not be practicable, five additional packers.
The  expanded fleet of twenty-nine packers would be needed to collect the
required tonnage and haul it to the new Murphy-Shepherd landfill.

In this specific case, failure to take into account the factor of lost col-
lection time would result in an error of $ 0.03 in the ton  minute unit cost
and  an underestimate of $70,000 in annual expenditures.  The mathematics of
these serious discrepancies is shown below:

                Cost Estimates Without Lost Time Correction

     In the standard formula for computing ton minute unit haul costs -

                                Total Hourly Packer Operating Cost
        Cost per Ton Minute  =
                                60 minutes x Average Payload (tons)
    substitute the appropriate data for a twenty-five cubic yard packer:
    $1^.65 hourly cost, seven-ton payload:

        Cost per Ton Minute  =    *    ^     « $ 0.03^8

                                  60 x 7

The estimated annual cost for direct haul is then obtained by multiplying the
above unit cost by the annual tonnage hauled and this product by the extra
haul time in minutes.  The annual tonnage figure is 87,360 (336 daily tonnage
                                     59

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times  260 working  days  in the year).  By this estimate, therefore -

     Annual  Increased Cost » $ 0.03^8 x 87,360 tons x 27 minutes » $ 82,083.^6

                 Cost Estimate With Lost Time Correction

On the basis  of  $1^.65  per hour for operating a twenty-five cubic yard, two-
man-crew  packer, the daily cost of operating (eight hour day) is $117.20 per
packer and  the five  additional packers required would thus cost $586* a day.
It follows  that  -

     True  Annual  Increased Cost = $586. x 260 working days = $152,360

This estimated annual cost, approximately $70,000 higher than that found by
the other method,  reflects the true increased cost due to increased haul time
(subsidiary work)  at the expense of collection time (productive work).

The true  cost per  ton minute in terms of this specific situation can now be
calculated  as follows:

     True  Cost per  Ton Minute = $^2,360 annual cost increase

                               87,360 annual tons x 27 minutes

                             = $ 0.065 for 27 minutes extra haul time for
                                 this size fleet

It  is  important to note that this unit cost per ton minute is not constant.
It  will vary  with any changes in fleet size and minutes per round trip.  Al-
though this method of estimating costs has general applicability, the amount
shown  relates only to the specific direct haul situation described and also
involves the  assumption that the problem would be met by adding packers to the
fleet  rather  than by continual overtime work, which would probably be even
more costly.:

To  summarize, the "standard" procedure often used for determining cost per ton
minute reflects only cost "on the road" and involves the erroneous assumption
that all other conditions will remain constant.   It does not take into account
the additional costs resulting from lost collection time.   In the true cost
shown  above for a specific San Diego situation,  this important factor has been
included in the computations.10 The annual extra cost of direct haul found in
that situation,  $152,360. will be compared with the costs  of two alternative
solutions of this particular problem:   (l) operation of a  conventional trans-
fer station and  (2) operation of a baling transfer station.
      See Appendix k for a presentation of the development of mathematical
      formulae with general applicability to direct haul studies.
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         Comparative Costs of Convention and Baling Transfer Stations

 Conventional Transfer Stations

 It is estimated that the cost of building a conventional transfer station
 having a nominal capacity of 350 tons  of refuse  a  day  (the approximate weight
 of refuse now being received by the Arizona Fill)  would be $95,750  and the
 cost of land for the site would be $1*2,360. The annual costs of amortizing
 these outlays are estimated at $6,858  and $2,ll8 respectively.  It is
 expected that annual current expenses  of operation,  including re-haul to the
 landfill, would be $196,630 and that the total cost for one year, including
 amortization of land and capital improvements, would be $205,6o6.  Details of
 the estimates are shown in Table 7 on page 62.

 The unit cost of this operation would  be $2.26 a ton on the basis of an annual
 nominal plant capacity of 91,000 tons  (350 tons  a  day for 260 days).  It
 should be noted that 350 tons a day is not the optimum capacity for a conven-
 tional transfer station and that this  unit cost  would undoubtedly be lower in
 a  larger station.

 Baling Transfer Stations

 The cost of  building and equipping a baling transfer station (see Table  8  on
 page  63) is estimated at $298,100 - three times as much as the capital outlay
 for construction required for a conventional transfer station.  Only a little
 more than a  third as much land is  required,  however, and this cost is esti-
 mated at $15,000 for the baling station.   Current  operating expenses are
 expected to  be  $166,698 for  one year (as  compared with a conventional station,
 it will be noted by comparing Tables  7 and 8,  plant labor and supplies and
 services are higher,  re-haul labor and equipment are lower, and certain types
 of "housekeeping"  plant  equipment  needed  in the conventional transfer station
 are not required in the  baling station).  As a result,  current operating
 expenses are almost $30,000  a  year lower  in the baling station than in the
 conventional station.  The  $192,996 total cost for a year,  including amorti-
 zation,  is about $13,000 lower.

 On the basis  of  91,000 tons  nominal capacity (the same as for the conventional
 transfer station),  the gross unit  cost of the baling transfer station opera-
 tion would be  $2.12 a ton.

 Cost Comparisons

 Before  a legitimate  comparison can be made between the  estimated annual costs
 of  the  conventional  transfer station and the baling transfer station (and
between both of these and the extra cost of longer direct haul to the  land-
fill),  it is necessary to examine the substantial savings that can be  effected
at  the  fill when the refuse is brought there in baled form.   As  shown  in Table
 9   on page  64,, these estimated savings amount to $35,6?2 in the  specific  San
Diego example being considered in this  chapter.
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                                  TABLE 7

      ESTIMATED ANNUAL COST OF A FULL-SCALE CONVENTIONAL TRANSFER STATION

                        (350 TONS NOMINAL DAILY CAPACITY)

                                                              Amount
      Item                                              Total          Annual*

Capital Investment Costs

  1.  Plant construction

         300 lin. ft. Ik'  high concrete retaining
             wall @ $125/ft.                          $ 1*1,250       $  2,163
       4,800 cu. yd. embankment @ $2/yd.                 9,600           480
       5,000 sq. ft. 5" concrete pavement @ $-70/sq.ft.  3,500           175
      30,000 sq. ft. 6" A.C. pavement @ $.60/sq. ft.     18,000         1,800
           1 each 40' truck scale                       12,000         1,200
         950 lin. ft. 8' chain-link fence @ $12/ft      11,400         1,140
                                                      $ 95,750       $  6,858

  2.  Land - 42,360 sq.ft. @ $l/s.q.ft. value            42,360         2,118

          TOTAL CAPITAL INVESTMENT COSTS              $138, HO       $  8,976

Current Operating Expenses

  3.  Plant labor
      1 equipment operator III                        $ 10,786
      1 equipment operator I                             6,500
      1/2 utility foreman                                 5,134       $22,420

  4.  Plant equipment
      1 sweeper ($3/hr)                                  6,240
      2 crane booms ($5/hr.  - 1 standby)                20,800       27,040

  5«  Re-haul labor and equipment
      3 heavy truck drivers                              26,6lO
      3 truck-tractor diesels ($5/hr)                    31,200
      6 sets gondola trailers ($7/hr.  set)               87,360       145,170

  6.  Supplies and services                                             2,000

          TOTAL CURRENT OPERATING EXPENSES                          $196,630

          Amortization (items 1 and 2  above)                            8,976

          TOTAL ANNUAL COST                                         $205,606

  ^Amortization computed on  the basis  of twenty  years for land, buildings, and
   earthwork and seven years for mobile  equipment.
                                      62

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                                    TABLE 8

           ESTIMATED ANNUAL COSTS OF A FULL-SCALE BALING TRANSFER STATION

                           (350 TONS NOMINAL DAILY CAPACITY)

                                                                  Amount
      Item                                                  Total        Annual*

Capital Investment Costs

  1.  Site preparation                                   $  3,800      $   350
  2.  Dumping pit with equipment                           73,800        6,866
  3.  Hogger with equipment                                81,800        6,551
  4.  Baler building with equipment                       126,700       10,581
  5.  One 40' truck scale                                  12,000        1,200

                                                         $298,100      $25,548

  6.  Land - 15,000 sq. ft. @ $l/sq. ft. value             15,000          750

          TOTAL CAPITAL INVESTMENT COSTS                 $313,100      $26,298

Current Operating Expenses

  7.  Plant labor
      1 utility foreman                                  $ 10,268
      5 laborers                                           38,300
      1 electrician (25% time)                              2,600      $51,168

  8.  Re-haul labor and equipment
      3 truck drivers                                    $ 26,610
      3 truck-tractors ($5/hr.)                            31,200
      6 trailers ($1.50/hr.)                                18,720      $76,530

  9.  Supplies and services
      Wire ties                                          $ 20,000
      Electrical power                                     15,000
      Water                                                 2,000
      Miscellaneous                                         2,000      $39,000

          TOTAL CURRENT OPERATING EXPENSES                            $166,698

          Amortization (Items 1-6 above)                                26,298

          TOTAL ANNUAL COST                                           $192,996


  *Amortization computed on the basis  of twenty years for building and
   earthwork, fifteen years for the hogger,  ten years for major
   machinery (including the baler)  and paving,  and seven years for
   mobile equipment.

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                                    TABLE 9

                       ANNUAL SAVINGS IN DISPOSAL COSTS


 1.   Present methods  of landfill operations cost an average of $0.81*2 a ton.*
2.  Estimated  annual  cost  of bale disposal:
         1 mobile crane @ $5/hr
         1 equipment operator III
         1 equipment operator III (30$)
         1 'bulldozer @ $l4/hr (30$)
         1 laborer

                              Total

3.  Cost per ton for bale  disposal = 	$40,819
                                                      $ 10,400
                                                        10,786
                                                         3,236
                                                         8,736
                                                         7,661
                                                      $ 1*0,819
                                                      	 = $0.448
                                     91,000 nominal tonnage**

4.  Present disposal cost ($0.842) minus estimated bale  disposal cost
    ($0.448) = $0.394 savings per ton, or $35,854 per year.
    **350 tons per day for 260 working days in the year.
                                   TABLE  10

  COMPARATIVE ANNUAL COSTS OF CONVENTIONAL AND BALING TRANSFER STATIONS
        Cost Item

1.  Amortization of station

2.  Amortization of land

3.  Plant costs (labor and equipment)

4.  Supplies and services

5-  Re-haul (labor and equipment)

              Total

    Disposal savings at $0.39/ton  (see Table 9)

    Total annual net costs
                                                 Conventional
                                                   Station

                                                 $   6,858
                                                    2,118
                                                   49,460
                                                    2,000

                                                 1^5,170
                                                 $205,606


                                                 $205,606
  Baling
  Station

$ 25,5^8
     750
  51,168

  39,000
  76,530
$192,996

  35,672
$157,324
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When these savings are taken into account the estimated net annual cost of
the haling transfer station operation is reduced to $1^7,964, which is
        a year lower than the cost of the conventional transfer station and
       less than the cost of direct haul (see Tablem  on page 64 ).  The
estimated unit costs per ton are $1.63 (baling station), $2.26 (conventional
station), and $1.67 (direct haul), under these specific conditions.

Summary of the Chapter

The potential economic benefits of baling refuse can probably be fully real-
ized only in the operational setting of a transfer station.  ?3ae transfer
concept, although not new, is receiving increasing attention as a means of
avoiding the expense of longer direct hauls by refuse collection vehicles to
more remote landfills when favorably located fills are exhausted.  A baling
transfer station would differ from a conventional transfer station chiefly in
(l) the presence of specialized processing equipment,  (2) a more sophisti-
cated system of conveying the materials from one stage to the next, and  (3)
the state of the refuse at the completion of the operation.

It is proposed that a pilot baling transfer station be built and operated
under realistic production conditions in order to evaluate technical and
economic aspects of the operation.  This station would cost $201,100 to build
and $127,200 to operate for a period of one year.

Economic feasibility studies based on information presently available indicate
that where the exhaustion of an existing favorably located landfill requires
longer direct haul to a more remote landfill,  and when the additional round-
trip distance required per truck exceeds about 9-5 miles,  a full-scale baling
transfer station would be more economical than direct hauling.  In the station
capacity range studied (350 tons a day),  a baling transfer station would be
substantially more economical than a conventional transfer station.
                                       6S

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                                 CHAPTER V

                                A  LOOK  AHEAD
 The purposes of this  chapter are  to place  in a larger frame of reference the
 one-year study and investigation  project which is described in the preceding
 chapters of  this report and to sketch briefly the follow-up study and possible
 eventual action that  are envisaged for  the future.

 As  was  pointed out in Chapter I,  it was planned that this study would repre-
 sent the first year of a possible three-year project in which the initial
 study and investigation phase would be  followed by a demonstration phase
 involving the construction and operation of  a pilot baling transfer station.
 This in turn,  if it proves successful,  is  expected to lead to practical
 changes in refuse disposal practice and procedures - in effect, to a realiza-
 tion of the  potential benefits of refuse baling that now seem to be promised
 by  the  initial studies.

 It  is believed that the two major objectives of the first phase have been met.
 In  the  first place, as outlined in Chapter m of this report, baling municipal
 refuse  is physically  and technically feasible in experimental situations.
 This was true even when (as in the local baling operation described in that
 chapter) conditions are not ideal.   A pilot  baling station is needed, however,
 to  test that feasibility under actual day-by-day production conditions with
 large quantities of material.   Secondly, Chapter IV provides theoretical
 evidence of  the economic  feasibility of using this process in combination with
 the transfer station  concept.   Here  again, the experience that can be gained
 with a  pilot station  is  needed as  a basis  for confirming or revising present
 tentative conclusions.

 Beyond  these major  objectives  the  first phase of the study had certain sub-
 sidiary purposes (set forth at the beginning of Chapter I) which were met with
 varying degrees of  comprehensiveness  during  the course of the project.   Limi-
 tations  imposed by  the  time available and by the size of the staff prevented
 the  exploration of  some of these in the depth that might have been desirable
 or  that  was  originally planned for the total three-year project.   In other
 cases the  conclusions  reached were tentative  1 n  nature because of the -theo-
 retical  and  experimental basis  for the investigation.   It may be  noted that
when this  study was undertaken  the baling of municipal refuse was a new and
unexplored field with virtually no basis of previous experience.   Some of
these areas which have not yet been fully investigated are discussed in a
 later section of this chapter.

 The  Proposed Demonstration Project

Based on the tentative conclusions set forth in the  body of  this  report,
construction of a pilot refuse baling transfer station is proposed in order to
demonstrate the technical and economic feasibility of  the process.  Prepara-
tion of  design plans and specifications and construction of  the facility are
scheduled for completion within nine months.   During the remaining three months
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 of the first demonstration year and throughout  the  second year primary
 emphasis will be directed toward gathering data for evaluating the operational
 and environmental effects of  baling refuse.

 Objectives  of the Project

 During the  first year  of  demonstration  and investigation, staff work will be
 directed toward developing final plans  and specifications for construction of
 the test facility.   Additional  work will  include preparation for plant opera-
 tional procedures and  staffing  and development  of techniques for data evalua-
 tion and for investigation of environmental effects of bale disposal in
 conjunction with efficient methods of bale landfill operations.

 Objectives  during the  second  year will  relate to the implementation of plans
 and procedures developed  in the first year.  The main emphasis will be:  (l)
 to develop  and evaluate data  on economics and techniques of pilot operation,
 (2) to develop and evaluate techniques  for efficient and effective disposal
 of refuse bales,  and (3)  to evaluate operational and environmental effects of
 baling refuse and to develop  standards  for comparison with conventional
 transfer station and landfill operations.

 Method of Procedure

 Final plans and specifications  for the  proposed 150-tons-a-day facility will
 be the responsibility  of  technical personnel assigned to the staff.  Addi-
 tional personnel from  the City  of San Diego's Engineering Department will be
 available for special  tasks as  required.   These special tasks will include
 obtaining the engineering survey of the pilot station site, preparation of
 design plans,  advertising of  construction bids*, awarding the contract, and
 supervision of plant construction and installation of equipment. .The Public
 Works and Purchasing Departments  will also provide personnel for plant staff-
 ing and for purchase of necessary equipment.

 At the completion of station  construction, tentative operational procedures
 established during the design phase will be initiated.  Preliminary plant
 staffing will require the  services  of a foreman, two laborers, and a heavy
 truck driver.   Prior to full-capacity operation, initial trials will be
 conducted to develop experience and, if required, effect correction of equip-
ment  performance.  Time schedules will be developed for delivery of incoming
 refuse,  processing of the refuse, and delivery to the disposal site.   Stress
will  be  placed on the analysis and  correction of operating problems (e.g.,
breakdowns,  procedures, noise factor, dust, sanitary methods) and the develop-
ment  of  effective and efficient rehaul  techniques (e.g., equipment, schedul-
 ing,  loading and unloading).

Continuing operation will provide data for developing and evaluating the
economics and techniques of the pilot operation.  Emphasis will be  placed on
the establishment of record keeping procedures (weights, densities, time and
motion studies, equipment performance,  costs,  etc.).  Data will be  used for
comparing the economics of a baling transfer station with direct haul and with
other transfer stations.
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 Further investigation is  planned in the area of developing and evaluating
 techniques for effective  disposal of refuse bales.  Experimentation with
 different types of  landfill equipment and bale handling procedures will be
 conducted at a selected test site.   This  investigation will be concerned with
 the determination of landfill preparation, cover dirt and finished slope
 requirements,  and the feasibility of small canyon bale disposal.  Supportive
 cost data for evaluation  purposes will be maintained.

 Operational investigation will include:   (l)  comparing densities obtained
 with shredded and unshredded refuse and with varying sizes of shredded par-
 ticles,  (2) determination of optimum water content to be added during baling,
 (3) experimentation to find optimum length of bales, and (U) procedures for
 separating ferrous  metals.   Technical data will be gathered for comparing and
 evaluating the baling landfill environment with that of conventional land-
 fills.   The areas of investigation will include:  (l) extent of gas production,
 (2)  odor production at the transfer station and in the landfill, (3) degree
 of  settlement or expansion,  (*»•) extent of temperature rise, (5) control of
 vector breeding both at the transfer station and at the landfill, and (6)
 extent  of water percolation.   It is expected that technical data will be com-
 piled over a period of several years in order to determine the long range
 effects  of landfilling with baled refuse.

 Evaluating the Project

 Plans and specifications  will be reviewed and approved, construction will be
 supervised during progress, and all work  done and equipment furnished will be
 inspected and checked against specifications, with testing where appropriate
 before acceptance.   Performance of  the heavy equipment (hogger, baler, and
 conveyors)  during the operation phase  of  the project will be Judged on the
 basis of direct observation and production and maintenance records.

 The project will be  evaluated on the basis of costs, compaction achieved,  dust,
 odor, handling and disposal problems, and on technological problems and pro-
 cedures  required in  the refuse  baling process.  Special studies will be
 designed (to be conducted insofar as is feasible during the course of the proj-
 ect and  to  be  followed up in  the  future) to evaluate the characteristics of
 baled refuse in the  landfill  as  compared to raw refuse compacted by standard
 methods, with  respect  to  decomposition, settlement,  gas production,  odor,  and
 vector breeding.  The  advice  of professional consultants in the field of sani-
 tary  engineering will be utilized in setting up these studies.

 During the  course of the  study  on solid waste disposal by the refuse baling
 method,  the  necessary  information and technology will be developed and in-
 cluded as part  of appropriate preliminary and final reports.   Conferences  will
be  held periodically with Federal and State officials and with private author-
 ities in the field to evaluate the effectiveness of the project and for mutual
 exchange of  information.
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 Areas of Special Interest

 During the course of the first phase of the project certain ramifications of
 the study were opened up which could not be fully explored due to limitations
 of time, staff, or financial resources.  Although resolution of these problem
 areas was not essential to the accomplishment of the study's tvo major objec-
 tives (determination of technical and economic feasibility), they are of
 sufficient interest and importance to justify special consideration in this
 chapter and special plans for follow-up studies in the second phase of the
 project.

 Factors Contributing to Bale Compaction

 In Chapter III it was reported that bales of refuse produced in the factory
 demonstration had markedly greater density than those produced in the local
 baling test (see page 3l).   In the absence of pertinent experimental evidence,
 the staff theorized that this difference could be attributed primarily to the
 amount of pressure applied by the two balers,  to the moisture content of the
 refuse,  and to pre-shredding of the material used in the factory demonstration.
 The known factors were the relative amounts of pressure exerted by the two
 balers and a reasonable assurance that the composition of the refuse  materials
 baled at the two locations was not dissimilar.   It was not possible,  however,
 either to process raw refuse in the factory baler or shredded refuse  in the
 local baler.   At the factory, moisture content was judged (on the  basis of one
 sample)  to be 30-0 Per cent.  In the local test it was not feasible to make
 accurate field measurement of moisture content.  It was therefore  suggested in
 the report that the contribution of variable factors to compaction be  deter-
 mined under controlled conditions in the second phase of the study.

 It should be  emphasized that these uncertainties in no way invalidate  the
 study's  basic conclusion that by baling refuse  under favorable  conditions it
 is feasible to obtain considerably greater compaction than is obtainable by
 conventional  landfill methods.  This was accomplished in the factory  demon-
 stration.   The point is  that accurate  evaluation of all of the  major contribu-
 tory factors  can help assure consistent realization of favorable results and
 perhaps  even  improve them at minimum cost.

 The two  factors which will be emphasized in  the tests  during the proposed
 pilot operation will be  moisture  content and pre-shredding,  rather than compo-
 sition of  the refuse or  pressure  applied by  the baler.   Composition of  the
 refuse is  expected to be reasonably constant (see Chapter II of this report).
 If necessary,  uniform batches will be  prepared  to insure uniformity for test
 purposes.   Baler  pressure will be held constant from bale to bale.  Plate 16
 on page  3 6 of the report shows the general relationship  between pressure  and
 compaction.

 Moisture content  of  the  incoming  refuse  varies  with the  season  and depending
•on the amount of  garbage and other wet material present.   Preliminary investi-
 gation indicates  that the  optimum moisture content  is about  30  per  cent and
 that additional water will generally have to be applied  to reach this level.
 The staff believes that  pre-shredding of refuse is  needed to prepare the
 material for more uniform absorption of  the  added moisture,  to  facilitate the
                                      69

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 movement of refuse on conveyor systems  (by reducing bridging), and to present
 a mechanically more homogeneous material  to the baler.  Pre-shredding breaks
 long,  tough fibers into shorter lengths and reduces paper to small pieces
 which when pressed together hold the  fines within the formed bale.

 It is  expected that in the  controlled tests contemplated, with refuse composi-
 tion and baler pressure held constant,  optimum moisture content parameters can
 be established for both raw and pre-shredded refuse.  With refuse composition,
 baler pressure,  and water content held  constant, the effect of pre-shredding
 or density can be determined.

 Limiting the Pilot Plant to City-collected Refuse

 It was noted on page 49 of  this report  that the character of refuse to be
 processed in the proposed baling pilot  station "must be controlled due to
 technical limitations of the hogger."   For this reason it was planned to
 process only City-collected refuse at this stage.

 This approach applies only  to the pilot station and not necessarily to a possi-
 ble future full-scale baling transfer station.  It is recognized that local
 government has the responsibility of insuring  that adequate disposal facilities
 are available for commercially and privately transported refuse.  Whether these
 are publicly or  privately operated and  whether the facilities are identical
 with,  or as favorably located as,  disposal sites for City-collected refuse are
 matters of municipal policy.   This need could  conceivably be met by insuring
 the continued availability  of  sanitary  landfills for commercial and private
 use, by setting  up dual type transfer stations, by installing heavier-duty
 (and considerably more expensive)  hoggers  in subsequent full-scale baling sta-
 tions,  or by other means.

 Neither the present report  nor the detailed proposals for a pilot baling sta-
 tion (described  in a preceding section  of  this chapter) are intended either to
 espouse or to prejudice  any particular  eventual solution to the problem of
 adequate refuse  disposal sites  for commercial and private carriers.  The opera-
 tional conception of a transfer station may be internal (jurisdictibnal vehi-
 cles only)  or external (both jurisdictional and public) or combinations thereof
 (i.e.,  jurisdictional and large  commercial haulers).  Local conditions in any
 City would determine  the  necessity of the type of transfer station service to
be  provided.

Neither are  the report's  cost comparisons between a full-scale baling transfer
station and a  conventional transfer station of the same size intended to imply
a permanent  policy  of  restriction  of input to City vehicles (see pages 61-65).
Direct haul  costs were figured in terms of available cost data.   Private haulers
will find different cost values for direct haul,  as will other cities,  when they
compute  their  costs.   The intent of the report was to show method rather than
constant unchanging values.

In addition  to the cost, however, there were certain definite  considerations
that led the staff to propose limiting the pilot  plant to City-collected refuse.
                                      70

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 First,  as previously stated in the  report,  there  is control over the type of
 refuse  coming in.

 Second,  during initial operation, breakdowns and  mechanical difficulties can
 be expected to halt production for  varying  lengths of time.  With the proposed
 location of the pilot station and with limitation to City collection vehicles,
 a plant breakdown would require only a short detour to our nearby Arizona
 Landfill.  Since Arizona Landfill is open only to City collection forces, how-
 ever, any private truck arriving at the baling station during a halt in opera-
 tions would have to be detoured to  Chollas  or Miramar Landfills which are
 approximately nine  miles away.

 Third,  it will be possible  to schedule City collection vehicles so as to insure
 a smooth flow of materials,  while private trucks  arriving at unscheduled times
 could create a supply of materials  far in excess  of the input storage capacity
 of the  plant.
 Reclamation  of gn»ll Canyons

 In this report the feasibility of utilizing small canyons as disposal sites
 for baled refuse was examined in a preliminary way.  It was pointed out that
 the baling process may open up this intriguing and potentially rewarding possi-
 bility because (l) it would permit the use of canyons which are too small for
 conventional, large-scale landfill operations and (2) it would be more accept-
 able to nearby householders since with refuse in baled form the operation would
 be cleaner,  quieter, and less odorous.

 Limited experimentation was conducted in the stacking or "nesting" of bales in
 a  simulated  landfill situation by means of a forklift (see discussion on page
 23 and pictures on pages - 24-27.) •  .These tests were inconclusive because (l)
 relatively few bales were disposed of in this manner, (2) since the locally
 fabricated bales were not well-shaped, it was impossible to "nest" them close
 together and consequently there were excessive voids between them, and (3) the
 forklift was found to be an inappropriate tool for this purpose.  A small can-
 yon site has been selected for bale disposal during the proposed demonstration
 phase of the project on a larger scale and under more realistic conditions than
 were possible during the study and investigation phase Just completed.  This
 canyon is located on City park land near the proposed pilot baling transfer
 station (see picture on page 53).
The basic operating procedure in the disposal of baled refuse in small canyons
will consist of four steps:  (l) bulldozers will "brush-off" the disposal area,
(2) bulldozers will "bench" the initial area and stockpile all earth removed,
(3) a traveling crane will pick up bales deposited from the re-haul vehicle and
ne»t them in one or more layers on the levelled area, and (k) a bulldozer will
cover the nested bales with earth as required.  Alternative procedures for
cover will also be investigated during the project.  The basic steps outlined
above dp not include compaction since that will have been accomplished by the
baler.
                                        71

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 It was pointed out in Chapter  I  of  this report that the topography of San
 Diego is characterized by the  presence of many large and small canyons.  Most
 of the larger canyons have been  preempted for freeways, arterial streets, or
 major drainage channels.   Many of the smaller canyons are located in close
 proximity to residential  districts.  Aot all of them are suitable or available
 for baled refuse  disposal sites, however, because of (l) a lack of accessi-
 bility to the canyon by disposal equipment, (2) an excessive number of drain-
 age structures emptying into the canyon, (3) a lack of adequate streets
 feeding the  area,  (k) the desirability of completing neighborhood fills of
 this type in a reasonably short  period of time, and (5) a multiplicity of own-
 erships within the canyon, making satisfactory lease or purchase negotiations
 impractical.

 Nevertheless,  the  staff's survey indicates thit approximately fifty small can-
 yons would meet all of the criteria implied by these limitations and probably
 could successfully be negotiated for and put into operation.  All of these
 fifty canyons  considered  suitable and available for this type of development
 have certain features in  common.  All of them have fairly steep sides and are
 in the order of eighty feet  deep.  Variations occur chiefly in the bottom
 slope and in the width between sides.  Due to these differences, they range
 from 70,000  to 350,000 cubic yards in total capacity.  In almost all cases a
 reasonable amount  of earth cover is available from the top of the canyon
 sides.

 Preliminary  studies  indicate that, because of these differences in capacity
 and depending  on quantities, unit disposal costs may vary markedly from can-
 yon to canyon  and  could probably range from an estimated $0.^5 to $2.00 a ton.
 It  should be noted that this may be considerably more than the cost of bale
 disposal in a  large  landfill operation (see Table  9 on page 64 ) because of
 the  different  conditions  that would be encountered in the small canyon opera-
 tion and the increases  in unit'costs that are inherent in a small operation.
 However,  the potential  advantages of filling the close-in sites as well as
 possible  transportation savings should justify the increased costs.   Firmer
 estimates  can be made after a basis of experience is built up during the
 demonstration phase  of  the project.

 It  is  estimated that the fifty suitable canyons would average about 200,000
 cubic yards in  capacity.  The total potential capacity that could be made
 available by disposing  of baled refuse in small canyons,  therefore,  is esti-
mated at approximately  10,000,000 cubic yards  - most of it favorably located
with  respect to collection area centroids.   Moreover,  the finished fills
would create a  total of approximately five  hundred acres  of attractive "green
belt" areas at precisely the points where they could contribute most to the
enhancement of urban living.   The need for  small "green areas" throughout  the
City has long been recognized by planning groups,  but the cost of developing
them by conventional earthfill methods  has  usually been prohibitive.   "The
fact  should not be overlooked that great benefit to  the community would result
from a planned program for acquiring and developing  many  such areas.   The
 small spaces of a city are equally important,  if not more so,  to  the people  of
a community,  as they are in constant everyday  contact with  these  areas."^

   The general  plan for San Diego—1985; presented by the Citizens' Advisory
   Committee  on the General Plan.


                                   72

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 The speed of filling these small canyons would depend on the number of baling
transfer stations in operation.  A 150-tons-a-day station would fill approxi-
mately ^5,000 cubic yards a year.

Summary of the Chapter

In reviewing this report and in looking ahead to the future it should be borne
in mind that the economic feasibility of baling as tentatively developed in
the study and investigation project is by no means the only or, in the long
view, the most compelling reason for constructing and operating a pilot baling
transfer station.  As long as the economics appear reasonable, economics should
be considered secondary to technology.  It is important, for example, to test
and evaluate, under realistic conditions, such technical aspects of refuse bal-
ing as (l) compaction obtainable, (2) optimum moisture content for effective
baling, and (3) possible hazards in bale disposal, such as gas production and
vector breeding.

It is also important to explore, under realistic conditions, the feasibility
of using bale disposal to reclaim small canyons near residential areas, where
full-scale landfill operations or the disposal of raw, unbaled refuse would
not be acceptable because of odor, dirt and noise.  There are many such canyons
in San Diego, some of them situated near the centroids of refuse collection
areas.

It is believed that this new and yet untried technique may be found to have
great potential not only in conserving sanitary landfill space and reducing
direct haul distances,  but also in contributing to the beautification of the
community and creating usable land for park, recreational and similar purposes.
Some of these benefits are intangible but they are no less worthwhile because
precise monetary values cannot be assigned to them.
                                      73

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APPENDIX
     74

-------
Ui
                                             CHARACTERISTICS OF  SAN DIEGO

                                   AND SIX SELECTED CITIES  OF COMPARABLE SIZE, I960
     Items

Population and Housing

  Total population
  Population density
    per square mile
  Percentage of housing in
    one-family units

Industry

  Number manufacturing estab-
    lishments of 20 or more
    employees per 100,000
  Number hotels, motels, tourist
    courts, camps, per 100,000

Climate

  Mean temperatures
    January
    July
  Mean annual precipitation
  Percentage possible sunshine
                                            San
                                           Diego
Boston
Buffalo
Cincin-
 nati
Pitts-
"burgb.
  San
Antonio
Seattle
                                          573,22U   697A97   532,759    502,550   60^,332   537,718   557,087

                                            2,9^    15A57    12,869     6,569    10,968     3,966     6,810

                                               71.1      16.U      28.3       37.1;       56.1      83.7      63.3
19.2
45.2
55.5
69.6
10 A
67

106.0
7.2
29-9
73.7
1+2.8
60

66 .k
11 A
23.5
69.8
35 e7
53

95.1
11.7
33-7
76.9
39-5
58

57-1
9-3
28.9
72.1
36,1
55

32.2
32.7
52.0
Qk.O
27.8
62

63.2
53-1
4l.2
65.6
3^.1
N.A.




I
       Source:  United States Bureau of the Census Reports,  I960

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                                                                          Appendix 2A
                          LETTER  OF  INQUIRY TO BALER MANUFACTURERS
THE  CITY  OF
SAN DIEGO
CITY ADMINISTRATION BUILDING • COMMUNITY CONCOURSE • SAN DIEGO • CALIFORNIA 92101
     PUBLIC WORKS
     DEPARTMENT

     LRIC QUARTLY
     DIRECTOR
                 213/990

                 August 21, 1967
                 Gentlemen:

                 Under a Federal Grant, the City of San Diego is  undertaking a  rather
                 thorough investigation of the feasibility of baling refuse  as  a means
                 of preserving our critical sanitary fill space.   Refuse  disposal  is
                 recognized as a nation-wide problem and accordingly our  project is
                 being jointly sponsored by the City of San Diego and the U.  S. Depart-
                 ment of Health, Education and Welfare under the  Solid Waste  Disposal
                 Act.  At the conclusion of our study, a detailed written report will
                 be prepared and printed for distribution to the  Department  of  Health,
                 Education and Welfare and other cities and counties in the  nation.

                 San Diego, like many other cities,  has undergone a  period of rapid
                 growth which is expected to continue for some time.  Our present  pop-
                 ulation of over 670,000 currently generates an estimated 350,000  tons
                 of solid waste refuse for disposal at our sanitary  fills each  year.
                 Over half of this refuse is municipally collected by our fleet of 65
                 packer trucks.  Based on current projections,  it is estimated  that
                 our annual tonnage generated will have doubled to about  700>000 tons
                 per year by 1985-  We estimate that we shall have to dispose of a
                 total of some 48 million tons of solid waste refuse in the next thirty
                 year period.  The problem of finding adequate space for  disposal  of
                 this refuse by sanitary fill method is becoming  an  increasingly
                 critical one.

                 Our first year of study will be primarily devoted to an  investigation
                 of the feasibility and economics of baling municipal refuse  and will
                                              76

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 Page 2
 August 21, 1967

 Federal Grant Baling Study
  include some preliminary testing of balers.  For this preliminary
  testing, we anticipate limiting our baling to refuse collected in
  our City packer trucks (25 yard capacity), therefore no salvaging
  or sorting is planned.  If baling appears to be practical, we intend
  to proceed with our plans to construct a pilot baling plant for more
  intensive testing during the second year of our project.

  We foresee several possible advantages in baling refuse :

     A.  Extending the life of our sanitary fills by obtaining
         greater compaction.

     B.  Shortening or eliminating the mid-day haul to the sanitary
         fill site with construction of baling/ transfer stations.

     C.  Possible cost reduction in handling refuse by bales.

  To our knowledge, there has been very little if any experimentation
  in the baling of refuse.   Since this is a new and as yet unproven
  application of baling equipment,  we are anxious to evaluate as many
  different types of balers as possible.  We would appreciate any
 brochures and information you may have on your baling equipment as
  well as your comments or suggestions on the potential adaptability
  of your equipment to the  baling of municipal refuse.

  Thanks in advance for your prompt attention.

       very truly,
  '-'       K" ......... )
"iric QuarTly"
 Project Director
                             77

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                                                            Appendix 2B
                     MAILING LIST OF BALER MANUFACTURERS
Adamson United Co.
730 Carroll  Street
Akron,  Ohio

Adco Manufacturing  Co.
726 Gay Street
Columbus, Ohio

American Baler Co.
26kQ Ohio Street
Bellevue, Ohio

American Baler Machines Co.
839 39th Street
Brooklyn, New  York

Apex Foundary  Division
 of Comet Industries Corp.
6lH South Eastern
Los Angeles, California

Apex Steel Corporation, Ltd.
6920 E.  Slauson Avenue
Los Angeles, California

Arnold  Hughes  Co.,  Inc.
6600 Mt. Elliott Avenue
Detroit, Michigan

Baldwin-Lima-Hamilton Corp.
 Eddystone Division
Philadelphia,  Pennsylvania

Balemaster Division
 East Chicago Machine Tool Corp.
4811 Railroad Avenue
East Chicago,  Indiana

Bemis Company,  Inc.
850-M Northstar Center
Minneapolis, Minnesota

Boland Machine  & Mfg. Co.
1000 Tchoupitoulas  Street
New Orleans, Louisiana

Boiling & Co.,  Inc.
3200 E. 65th Street
Cleveland,  Ohio
 M.  E.  Canfield Co.
 1+19 East 3rd
 Los Angeles,  California

 J.  I.  Case  Co.
 700 State Street
 Racine,  Wisconsin

 Cardwell Machine  Co.
 19th & Franklin Streets
 Richmond, Virginia

 Chattanooga Welding & Machine Co.
 Chestnut &  13th Streets
 Chattanooga,  Tennessee

 Consolidated Baling Machine Co.,
 ho6 Third Avenue
 Brooklyn, New York

 Consolidated Baling Machines
 3690 South  Santa Fe
 Vernon,  California

 Cox &  Sons  Co.
 Water  £  Hampton Streets
 Bridgetown, New Jersey

 Dempster Bros., Inc.
 Springdale  Ave. & South R.R.
 Khoxville,  Tennessee

 Dover  Corporation
 Elevator Division
 P.  0.  Box 2177
 Memphis,  Tennessee

 Dunning  & Boschert  Press Co.
 379 W. Water  Street
 Syracuse, New York

 Economy  Baler Co.
 1032 McDonald Street  .
 Ann Arbor, Michigan

 Galland-Henning Mfg. Co.
 2761 South 31st Street
Milwaukee, Wisconsin
                                      78

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                                                          Appendix 2B
 General Hydraulics  of
 1*11  South Flower
 Burbank,  California
Calif., Inc.
Nichols Baling Presses
2646 Downey Road
Los Angeles, California
 Jules  D.  Gratiot  Co.
 3423 Verdugo Road
 Los Angeles, California

 H-P-M  Division, Koehring Co.
 840 Marion Road
 Mt. Gilead, Ohio

 T. W.  Hall Co.
 59 Sunnyside Avenue
 Stamford, Connecticut

 Harris Press & Shear Corp.
 Simmons Building
 Cordele,  Georgia

 Harris Waste Paper Baler
 4551 East Gage
 Bell,  California

 Johnson Manufacturing Co.
 P. 0.  Box 311
 Chippawa  Falls, Wisconsin

 Lake Engineering  Co.
 310 Gostlin Street
 Hammond,  Indiana

 E. W.  Loeser Co.
 1355 Genesee Street
 Buffalo, New York

 Logemann Brothers Co.
 3225 North Pierce Street
 Milwaukee, Wisconsin

 Maren  Engineering Corp.
 16246  School Street
 South  Holland, Illinois

Minnich Machine Works
 1607 Ridgely Street
 Baltimore, Maryland

National Balers
 1071 E. 48th Street
Brooklyn, New York
                    Rapids Machinery Co.
                    875 llth Street
                    Marion, Iowa
                      Inc,
                    Salem-Brosius, Inc.
                    P. 0. Box 2222
                    Pittsburgh, Pennsylvania

                    Schick Baler Corp.
                    433 York Avenue
                    Philadelphia, Pennsylvania

                    Steel Equipment Co^
                    P. 0. Box 737-M
                    Cleveland, Ohio

                    Tamaker Corp.
                    6411 Ventura Boulevard
                    Ventura, California

                    Taylor-Wilson Mfg. Co.
                    1603 Keenan Building
                    Pittsburgh, Pennsylvania

                    Ther Electric & Machine Works
                    17 South Jefferson Street
                    Chicago, Illinois

                    Tonawanda Engineering Co.
                    Tonawanda, New York

                    Turner Manufacturing Co.
                    Statesville,  North Carolina

                    Watson-Stillman Press Division
                      Farrel-Birminghara,  Inc.
                    565 Blossom Road
                    Rochester, New York

                    Wenzelman Manufacturing Co.
                    1172 North Broad Street
                    Galesburg, Illinois
                   West Engineering Co.
                   Dill Road & Vawter
                   Richmond,  Virginia
                      Inc.
                                      79

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                                                           Appendix 3
    THE AMERICAN BALER COMPANY
TELEPHONE AREA 419, 483-5790
               BELLEVUE, OHIO
         January 12, .1968
                  NOTES ON BALING TEST RUN
           BY THE AMERICAN BALER CO. AT ITS PLANT
         IN BELLEVUE, OHIO. TUESDAY,  JANUARY 9,  1968
 In view of the size of the current problem in handling solid -wastes, and
 particularly the transportation and disposition of such materials,  it
 seems important.to analyze what can be done with existing techniques,
 and to inquire into the possibility of  improving these techniques either
 as to capacity or results.

 We arranged to send a packer truck  to Louisville, Kentucky, where Mr.
 Charles Bennett at the Department of Sanitation,  Incinerator Plant, gra-
 ciously took the time to prepare two  packer loads of typical refuse.  He
 reports that one load was brought in  from a fairly affluent section of the
 town and another one from a less affluent, where the percentage of gar-
 bage was relatively high.  Both samples contained significant amounts
 of bottles,  cans and  plastic containers.  Measured free density of the
 stock as fed to the baler was 11.4 p.c.f.   In 1956, the City of Louisville
 had installed a Williams Model 445 No-Knife Hog for reducing large
 pieces of lumber and automobile and truck tires,  etc. and the above two
 loads were processed through this hog and loaded into our chartered
 packer truck and brought to the plant in Bellevue. The effects of being
 in the packer truck were removed by running through our shredder and
 air system. At this  plant we maintain.a demonstration system including
 a standard model continuous heavy duty horizontal baler.   This baler,
 however,  is equipped with a larger main hydraulic cylinder so that tests
 can be run at greater pressures than normally used in collection of
 secondary fibers for return to the paper mills.  Plans were made  for
 adding water to this  material.  However,  this proved unnecessary as the
 moisture content of one sample taken at about the middle  of the test was
 30.0%.  Four complete bales were made and measured as follows:
       1.    26" x 36" x 75"
       2.    26" x 36" x 78"
       3.    26" x 36" x 48"
       4.    26" x 36" x 71"
2,210#
2,, 490#
1, 500#
2, 125#
54.3 pcf
59.0 pcf
57.7 Dcf
55.3 pcf
                              80

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Then, two smaller bales were  made, one of which was taken back to the
United States Public Health Service  in Cincinnati by Mr.  Donald A.
Oberacker, and the other was opened for inspection.  A  section of this
was dropped into a tank of water,  and predictably floated about 92%  sub-
merged.  These  densities were then checked on the pressure density
curve made in connection with  some earlier tests in 1963,  indicating the
final densities wen.' as great or greater than the more favorable of the
two curves plotted at that time. A copy is attached marked Figure 1.
One possible explanation of this is that moisture content  had been  lower
on  the earlier  test.   Figures 2A and 2B  show respectively the particle
size of the loose material (this can be compared with the 10-foot rule
illustrated in the circle).   Figure  2B is  a view of the  discharge end of
the baler showing the nature of the continuous operation.  Figure 3 is
a picture of the above Bale #1.   Note:  Corrugated end pads were used
during part, of  the test, but in our  opinion would not be necessary in actual
practice on a production  basis with this  product.

After seeing the above  results and comparing these densities, it can  be
safely predicted that the  method can be used to produce bales of t>5 to
70  p. c. f.  A baler of this type is feasible to run at a rate of up to  25  tons
per hour.  Baler capacity might be pushed somewhat  beyond this,  but. it
is probable that two men tying the  bales would find the above figure a
comfortable operating rate.

On  checking the extension produced without tying the bale, the resultant
density was 45 p. c.f.   If these  "pads11 were  removed  by  conveyor  to
trucks or railroad cars,  and loaded  random., we would estimate load
density at about. 35 p.c. f.   By  1500  Friday,  January  12,  a probe ther-
mometer in Bale #4 read 98° F. in 70° room temperature.

After the baling tests,  a  general discussion was held  about the nature
of the equipment.  Tin- shredder actually used for this test has been in
service  11 years and questions  regarding maintenance cost, if any,
could be  obtained directly from Mr.  Bennett. Similar shredders have
been used in paper stock processing plants for over 15 years,  and the
current trend in such plants is  to convert to  the shredder-continuous
baler method.

Preliminary  discussions  as to the  general cost of this type of system
indicate  the equipment  cost for  a plant to run at 50 tons an hour might
run between $125,000 to $140,000.   However, no absolute predictions
are-possible  because of local conditions,  the'distance to  proposed  land-
fills, the possibility of requiring the extra density to  insure the bale
                                  81

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will sink in saltwater,  and the question of how much overdesign should
be provided in the slm-dder to reduce the discipline required in elimi-
nating particularly bothersome items,  for  instance, heavy water heaters.
All will effect the final result.  The above  estimate was based on a
heavy duty shredder  that would accommodate most of the usual metallic
items, but should be  protected from heavy water heaters.  The resultant
discipline required Tor this type of equipment would not be onerous in
any well-organized .system.

Here at American Baler we came  to the conclusion that this method is
completely feasible and offers a high probability of economic success.
This conclusion is bricked up by our decision to proceed with the manu-
facture of a Model 12375  Baler,  which we are prepared to guarantee to
produce 25 gross tons per hour on properly shredded material run  at a
moisture rate of approximately 30%.  Density will run  65  to 70 p.c.f. --
bale weight 3200# to  3500#.

                                   THE AMERICAN BALER CO.
                                   R.  E. Seltzer
                                   President
                                 82

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                             T.   le u if
-55"
mr    so
                                      ss
Bo    8$
                                     83
                               Figure 1
                                                                  -/^.^ 3

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                                                                Appendix
                      MATHEMATICS OF DIRECT HAUL COSTS

 In Chapter  IV of  this report  it was shown  that the true cost of the extra
 distance to a more  remote location that refuse collection vehicles must
 travel when close-in landfills are exhausted must reflect the reduction in
 collection  time resulting from extra time  on the road (see page 60  ).  Since
 it is usually not practicable to compensate for this lost collection time by
 constant overtime (in effect  a permanent lengthening of the working day), the
 number of collection vehicles must be  increased.

 The purpose of this appendix  is to describe the mathematics of determining
 the necessary fleet size (and thus the true additional cost) under the new
 conditions.
First, certain constants were developed in general terms:



    1.  Daily collection minutes per ton =
                                          Present collection minutes
                                              per day per truck
                                                Present average tons
                                                 per day per truck
    n   _  .,   _,   .   '          /Present number x   . .      /Average daily tons
    2.  Daily  fleet tonnage .   (               )  times   (
                              Qf

3.  Daily reduced    _  /Present collec- \         /Extra minutes %
                     ~  *                '  — ^-^-
                         _
         collection time ~   * tion minutes   '  — ^-^-  ^of. daily haul

        _       , .       n .          Daily reduced collection time
        Long haul tons collec-
         tion ability per truck ~

    5.  Long haul fleet size =
                                Daily collection minutes per ton

                              Daily total fleet tons (No. 2 above)

                             Long haul tons per truck (No. h above)
Substituting in No. f> with original values, it is found that:

        Long haul fleet size equals (present number of trucks) times
        (average daily tons per truck) divided by the quantity
        (present collection minutes minus extra minutes of daily
        haul divided by the quantity {present collection minutes per
        day per truck divided by average daily tons per truck ~] )

Or:
        (Present number of trucks)  times  (Average daily tons per truck)

         Present collection minutes  minus  Extra minutes of daily haul

              r- Present collection minutes per day per truck  ~j

              ^-          Average daily tons per truck


                                      84

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                                                              Appendix 4
                                                              (continued)
Collecting the terms, it is found:

         _,     ,     ,             .        ,  . _           Present collection
         present number}        (Average daily  }       ( minuteg          }
         x  of trucks   ' 	  xtons per truck7 	 v       .    ,    J  '
                                     *                    per truck

         /Present collection minutes minus\  , .     /Average daily tons\
           extra minutes of daily haul      	       per truck

Canceling  (Average daily tons per truck) the formula becomes:

                                          Present collection minutes
  Long haul     Present number   ,.            per day per truck
   j^-i  j_  j   =    n ,    i        times
   fleet size     of trucks     	
                                         (Present collection minutes)
                                        minus (Extra minutes of daily haul)

If the number of trucks factor is omitted, a simple ratio develops by which
the present fleet size may be multiplied to determine the size of the new
longer haul fleet size.  Whether to round up or round down to the next higher
or lower whole truck, when a fractional truck results from the formula, is a
practical administrative decision which must take into account such factors
as fleet size, labor conditions, overtime rates, and "swing crew" policy.


To determine the true cost of the longer direct haul, multiply the annual
cost of a truck with crew by the number of extra trucks needed.

Example:

    Assumptions:   30-truck present fleet carrying 15 tons per day each
                    7-5 tons collected per truck per trip
                  340 minutes collection time
                   18 miles addition per round trip
                   22 miles per hour travel speed
              $30,000 annual cost per truck with crew


    Computation:   18 miles @ 22 M.P.H. equals 49 minutes per trip
                   or 98 minutes per day lost from collection time
                   (30)
   340	  _  42.15 (say 42) trucks needed
340 - 98      "                for the longer haul
                   42 - 30 = 12 additional trucks
                   12 ($30,000) = $360,000 extra annual cost of  long haul

                   30 (15) 260  =  117,000 annual tons  to be handled

                 117?000°(49)   = $0.0628 cost  per ton/minute
                                      85

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                                                                Appendix 5
                    COST OF  PRE-SHREDDIWG MUNICIPAL REFUSE


 The estimated pre-shredding costs presented  in this Appendix include   (l)
 depreciation on the plant and equipment,   (2) power, and   (3) maintenance on
 the hogger (shredder).   Other elements of  cost are considered to be negligi-
 ble .

 Estimates  of maintenance costs for the hogger being considered for the pro-
 posed pilot baling station  are based on the  experience of a present user of
 the same equipment (same manufacturer and  same model) for the same purpose
 (shredding municipal refuse).  An excerpt  from a letter written on March 25,
 1968,  by Mr. Gerald T.  Vaughn, Sr., Plant  Manager of Lone Star Organics, Inc.,
 Houston, Texas,  in response to our inquiry,  appears below:

              We  are grinding our total intake of 330 tons or more
              per day with this shredder.   It is being powered by
              a  500 H.P.  motor  at 900 R.P.M.  with a capaicty of up
              to  50 tons  per hour.

              The hammers are removed and resurfaced every 1200 to
              1500  tons,  or  every fourth day.  There does not
              appear to be a great deal of wear on the shredder
              itself.  Removal  of the hammers and replacing with
              rebuilt ones requires an average of 6 man hours - we
              use a 3 mau crew for an average time of 2 hours -
              this  was somewhat higher before the crew learned the
              proper procedure.  The average resurfacing time is
              about 10-12 man hours.  You should be able to arrive
              at  some cost factors with this  information using
              your  labor  rates in the San Diego area.

Multiplying  the  total of 18 man hours required per 1,500 tons (6 hours to
remove and replace  and 12 hours to resurface hammers) by San Diego's hourly
cost of $6.10 for  this kind  of work yields $109.80.   Adding $U0.20 to this
for necessary materials  and  overhead brings the total maintenance cost to
$150 per 1,5OO tons  or $0.1O a ton.

In the table  on page 87  this unit cost is added to  depreciation and power
costs to arrive at a total cost for pre-shredding in a pilot baling transfer
station and  in a full-scale station.   The only difference in capital invest-
ment needed for a full-scale station versus a pilot  station is  in the size of
the hogger motor, estimated to cost an additional $100 per year.   The full-
scale station requires a 500 H.P.  motor to process 50 tons an hour and the
pilot plant a 300 H.P. motor for a capacity of 30 tons  an hour.
                                      86

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                                                               Appendix 5
                                                               (continued)
         PRE-SHREDDING COSTS IN PILOT AND FULL-SCALE BALING STATIONS

                                                   C  o  s  t  s
                                               Per        Per         Per
 Items                                          Year       Day         Ton.

 Pilot Baling Station  (150 tons per day)

   Depreciation
     - on $50,000 for hogger, motor, and
          appurtenances @ 10 years            $ 5,000
     - on $25,000 for building and con-
          veyors @ 20 years                     1,250

   Power                                        7,000

              Total                           $13,250    $51.00a    $ 0.3^b

   Maintenance  (see page 86)                                          0.10

              Total                                                 $ O.kk


 Full-scale Station (350 tons per day)

   Depreciation
     - on $51,000 for hogger, motor, and
          appurtences @ 10 years              $ 5,100
     - on $25,000 for building and con-
          veyors @ 20 years                     1,250

   Power                                       12,000

              Total                           $18,350    $70.58C    $ 0.20d

   Maintenance  (see page 86)                                          Q.IQ

              Total                                                 $ 0.30
a - $13,250 divided by 260 working days in the year.

b - $    51 divided by 150 tons.
c - $18,350 divided by 260 working days in the year.

d - $    70.58 divided by 350 tons.
                                       87

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                              SELECTED  BIBLIOGRAPHY
American  Public Works  Association.   Municipal  refuse  disposal.   2d  ed.   Chicago,
      Public Administration Service,  1966.   526 p.

American  Public Works  Association.   Refuse  collection practice.   3d ed.   Chicago,
      Public Administration Service,  1966.   525 p.

Analysis  of refuse  collections  and hauling  operations, June—November  1958.
      Pasadena, Engineering-Science,  Inc.,  [1958],   [92 p.]

Barail, L. C.  Packaging  engineering.  New  York, Reinhold Publishing Corporation,
      1954.  407 p.

Bugher, R. D.  Solid wastes research needs.  APWA Special Report  24.  Chicago,
      American Public Works Association, May 1962.   80 p.

Department of Public Works.  Refuse disposal site survey; [part 3].  Sacramento
      County,  [1966].   [89 p.]

Engineering Foundation Research Conference; Solid Waste Research  and Development,
      University School, Milwaukee, Wis., July  24-28,  1967.   [185  p.]

Financing municipal refuse collection operations.   City of San Diego, Feb. 20,
      1968.  20 p.

Master plan of refuse disposal.  Santa Ana, Orange  County Highway Department,
      1959.  58 p.

Mendoza, E.  Factors in an efficient refuse collection system.  Public Works,
     94(1):128-129, Jan. 1963.

[Mimeographed appendix.]  I_n_ The general plan  for San Diego—1985; presented by
     the Citizens' Advisory~~Committee on the General  Plan.  Adopted on March 24,
      1965, by the San Diego City Planning Commission.  Adopted on April  22, 1965,
     by the San Diego City Council.  [227 p.]

The Orange County refuse disposal program.  Santa Ana, Orange County, 1965.  44 p.

Proceedings;  National Conference on Solid Waste Research, University of Chicago
     Center for Continuing Education, Dec.  1963.   American Public Works Associ-
     ation, Feb.  1964.   228 p.

-------
Pyrolysis of solid municipal wastes.  City of San Diego, Feb.-1970.   [35 p.]

Report on refuse collection and disposal, Los Angeles, California.   [Kansas City,
     Mo.], Black § Veatch, 1960.  201 p.

Size reduction of bulky metal objects by compression presses.  In Day §
     Zimmermann, Engineers and Architects.  Special studies for~he Government
     of the District of Columbia, Department of Sanitary Engineering.  Public
     Health Service Publication No. 1748.  Washington, U.S. Government Printing
     Office, 1968.  p. 47-53.

Size reduction of oversize burnable waste.  In Day § Zimmermann, Engineers and
     Architects.  Special studies for incinerators for the Government of the
     District of Columbia, Department of Sanitary Engineering.  Public Health
     Service Publication No. 1748.  Washington, U.S. Government Printing Office,
     1968.  p. 39-46.

Solid waste disposal study; phase one.  A staff report to the Regional Solid
     Waste Committee of Clinton, Eaton and Ingham Counties.  Lansing, Tri-County
     Regional Planning Commission, Dec. 1966.  59 p.                      ;.

Stern, W.  The package engineering handbook.  Rev. version.  Chicago, Board
     Products Publishing Company, [1949].  175 p.

[The visitor industry.  San Diego, Copley Press, Inc., 1962.  11 p.]

Waste management and control; a report to the Federal Council for Science and
     and Technology.  Publication 1400.  Washington, National Academy of
     Sciences—National Research Council, 1966.  257 p.
                                                                uo-374
                                       8!

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     THE  FOLLOWING  PAGES ARE DUPLICATES OF





  ILLUSTRATIONS APPEARING ELSEWHERE IN THIS






 REPORT.   THEY HAVE BEEN  REPRODUCED HERE BY





A DIFFERENT METHOD TO PROVIDE BETTER DETAIL.

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          DESIGN AND OPERATION OF THE LOCAL TEST FACILITY
FIGURE  1
                                                       General view of
                                                       test facility
                                                       during construction
Refuse  is dumped
at the  upper level
                                                      A  skip loader  cuts
                                                      into the pile  of
                                                      refuse
                                                            This page is reproduced at the
                                                            back of the report by a different
                                                            reproduction method to provide
                                                            better detail
                                     15

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                  VIEWS OF LOCAL BALE DISPOSAL EXPERIMENT     FIGURE 6
 Hillside  before
 being  cut to
 create simulated
 landfill
'
                                                                 '


                                                          Fill cutting job
                                                          approaches completion
 Some  of the bales
 are dumped on the
 ground for pick-up
 by the fork lift
This page is  reproduced at the
back of the report by a different
reproduction method  to provide
better detail.
                                       24

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  ON
II
8 8
      '
 rf

 ff8
 3 g»R
         VIEW OF LOCAL BALE DISPOSAL EXPERIMENT
                                                                                                      Stacked bales

                                                                                                    viewed from above
                                                                                                                           M
                                                                                                                           o
                                                                                                                           oo

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COMPARISON OF RAW MATERIALS.  LOCAL AND FACTORY TESTS
                                                                                    Unprocessed refuse was used
                                                                                    in the local baling tests
                                                                                                                     ro

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       COMPARISON OF THE FINISHED PRODUCT
                                                                                            These bales were produced
                                                                                               San Diego's local  test
B*
                                                                                                                           H

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   THREE VIEWS OF A SMALL CANYON PROPOSED FOR RECLAMATION
                                                                  FIGURE 21


                                                         This canyon  is  too small
                                                         and too near a  residen-
                                                         tial area for a conven-
                                                         tional fill  operation
But it could be box-cut
and filled with nested
bales of refuse and
covered with earth
                                                        Making possible a valuable
                                                        extension of a city golf
                                                        course's present cramped
                                                        parking lot
                                         51
This page is reproduced at the
back of the report bv a different
reproduction  method to provide
better detail.

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Aerial view of small canyon proposed
for reclamation (upper arrow) and
proposed site for pilot station at the
Central Operations Center  (lower arrow)
                                                                                                                      ro
                                                                                                                      ro

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