Material Recovery Facilities for Municipal Solid Waste


         United States
         Environmental Protection
         Agency
Office of
Research and Development
Washington, DC 20460
EPA/625/6-91/031
September 1991
EPA     Handbook
         Material Recovery
         Facilities for
         Municipal Solid Waste

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                                    EPA 625/6-91/031
                                      September 1991
               HANDBOOK
     MATERIAL RECOVERY FACILITIES
       FOR MUNICIPAL SOLID WASTE
                  by

        PEER CONSULTANTS, P.C.
          Dayton, Ohio 45432
                  and

          CalRecovery,  Inc.
          Richmond, CA 94804
       Contract No.  68-03-3490
         Work Assignment 3-13
           Project Officer

            Edwin F.  Earth
 U.S.  Environmental Protection Agency
    26 W.  Martin Luther King Drive
         Cincinnati,  OH 45268
U.S.. Environmental Protection Agency
  Office of Research and Development
        Washington,  D.C. 20460
                                   Printed on Recycled Paper

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                              NOTICE

     This document is intended to assist regional,  state, and local
community  personnel,  as  well  as  individuals  or  corporations
considering  the establishment  of a  material recovery  facility
(MRF) .   This document is  not a regulation and should not be used as
such-.  The users of this handbook must  exercise their discretion in
using the  information  contained herein  as  well  as other relevant
information when evaluating MRFs.  The development and compilation
of the  guidance and information contained in this handbook has been
funded  wholly  or  in  part by  the United  States  Environmental
Protection Agency through Contract 68-03-3490 to PEER Consultants,
P.C. .
     Mention  of  trade  names  or  commercial products
constitute endorsement or recommendation for use.
does  not
                               11

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                             ABSTRACT

     The purpose of this document is to address the technical and
economic aspects of material  recovery facility  (MRF) equipment and
technology in such a manner that  the document may be of assistance
to solid waste planners and engineers at the  local community level.
This  document points  out what  technically  can  be  done,  what
material specifications  can  be achieved,  and  what the  different
manual and mechanical materials separation and recovery approaches
can cost.

     This handbook is designed for use primarily by engineering or
other technically trained personnel who  are  engaged in some aspect
of  design,  specification, purchase, or implementation  of  MRFs.
Sources  of  information   for  this  document include  the  design
engineering community,  vendors of equipment, and  various studies
funded by the U.S. EPA.   Of course,  many presently operating MRFs
also served as prime sources  of information.
                               111

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                             CONTENTS
Notice	ii
Abstract	iv
Figures	vii
Tables	viii
Acknowledgement 	 ..... x

  1  Introduction	1-1

  2  Specific Approaches to Materials Recovery  	 2-1
     2.1  Introduction	2-1
     2.2  Concept Description 	 2-1
          2.2.1   Basic MRF	2-2
          2.2.2   Variations from the Basic MRF	2-5
     2.3  Technical	2-5
          2.3.1   Waste Characterization  	 2-5
          2.3.2   Mass Balance	2-7
          2.3.3   Technology Considerations for a Basic MRF . 2-9
          2.3.4   Finished Product Specifications 	 2-9
          2.3.5   Flow Chart and Mass Balance—Low
                  Technology	2-9
          2.3.6   Flow Chart and Mass Balance—High
                  Technology—Paper Line	2-16
          2.3.7   Flow Chart and Mass Balance—High
                  Technology—Commingled Container Line .  .  2-16
          2.3.8   Flow Charts/General Comment 	  2-23
          2.3.9   Material Densities  	  2-23
          2.3.10  Fixed Equipment 	  2-25
          2.3.11  Rolling Equipment 	  2-55
          2.3.12  Human Factors 	  2-57
          2.3.13  Acceptable Waste  	  2-64
          2.3.14  Raw Material Storage  	  2-64
          2.3.15  Product Storage 	  2-66
          2.3.16  Building  	  2-66
     2.4  MRF Management	2-66
          2.4.1   Organization	2-66
          2.4.2   Operating Schedules 	  2-68
          2.4.3   Job Descriptions	2-68
          2.4.4   Health and Safety Considerations  ....  2-71
     2.5  MRF Economic Analysis	2-71
          2.5.1   Introduction	2-71
          2.5.2   Composition of Recyclables  	  2-72
          2.5.3   Capital  Costs	2-72
          2.5.4   Operating Costs	2-79
          2.5.5   Sensitivity of Capital and Operating
                  Costs	2-82
     2.6  Performance Guarantees  	   2-82
          2.6.1   Facility Availability  	   2-82
          2.6.2   Facility Capacity 	   2-82
          2.6.3   Environmental  Guarantee 	   2-83
                               v

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                       CONTENTS (Continued)
     2.7  Marketing	2-83
          2.7.1   Market Concerns for Recovered Wastepaper   2-83
          2.7.2   Market Concerns for Recovered Steel
                  Containers	2-84
          2.7.3   Market Concerns for Recovered Glass .  .   .  2-87
          2.7.4   Market Concerns for Recovered Aluminum   .  2-90

  3  General MRF Concerns 	 3-1
     3.1  Siting and Permitting Concerns  	 3-1
     3.2  Contracting Issues	3-4
          3.2.1   Contractual Arrangements  	  .3-5
          3.2.2   Flow Control	3-8

Appendix A - Glossary	 A-l
Appendix B - List of Material Grades and Specifications .   .  . B-l
Appendix C - Examples of Maintenance Procedures 	 C-l
Bibliography  	  BB-l
                               VI

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                             FIGURES
Number

 2-1
 2-2
 2-3

 2-4

 2-5

 2-6

 2-7
 2-8
 2-9
 2-10
 2-11
 2-12
 2-13
 2-14
 2-15
 2-16
 2-17
 2-18
 2-19
 2-20
 2-21
 2-22

 2-23
 2-24

 2-25
 3-1
 Flow  Chart  Source  Separated Materials  	  2-3
 Summary  Flow  Chart and Mass Balance	2-10
 Flow  Chart  and Mass Balance—Low Technology—
 Paper Line	2-13
 Flow  Chart  and Mass Balance—Low Technology—
 Commingled  Container Line  	   2-14
 Flow  Chart  and Mass Balance—High Technology—
 Paper Line	2-17
 Flow  Chart  and Mass Balance—High Technology—
 Commingled  Container Line  	   2-18
 Flow  Chart—High Technology—Ferrous Module . .  .   2-19
 Flow  Chart—High Technology—Glass Module  ....   2-21
 Flow  Chart—High Technology—Plastics Module  .  .   2-22
 Flow  Chart—High Technology—Aluminum Module  .  .   2-24
 Trough Type Belt Conveyor	2-29
 Belt  Conveyor with  Skirtboards	2-29
 Multiple Magnetic  Drum   	   2-36
 Magnetic Head Pulley	2-36
 Magnetic Belt	2-37
 Disc  Screen	2-37
 Trommel Screen  	   2-39
 Vibrating Screen   	   2-39
 Vertical Air Classifiers   	   2-41
 Typical Range of Dimensions for Can Densifiers   .   2-43
 Typical Range of Dimensions for Can Flatteners   .   2-44
 Typical Range of Dimensions for Glass Crushers
 (with Infeed Conveyor)   	  2-46
 Baler	2-46
Typical Range of Dimension for Single Ram
 Balers	2-48
Typical Range of Dimension for Two Ram Balers .   .  2-48
The Three-Phase Siting Framework  	 3-2
                              Vll

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                              TABLES


Number                                                       Page

 2.1      Example of Composition of Residential Curbside
          Recyclables	2-6
 2.2      Common Design Considerations of Low Technology
          Systems	2-11
 2.3      Common Design Considerations of High Technology
          Systems	2-12
 2.4      Factors Affecting Material Recovery Rate  ....  2-15
 2.5      Average Densities of Refuse Components  	  2-26
 2.6      Fixed Equipment Which May be Employed in a
          Materials Recovery Facility 	  2-27
 2.7      Approximate Conveyor Belt Capacities (20° Trough)
          (TPH)	2-30
 2.8      Approximate Conveyor Belt Capacities (35° Trough)
          (TPH)	2-31
 2.9      Approximate Conveyor Belt Capacities (Flat Belt)
          (TPH)	2-32
 2.10     Approximate Conveyor Belt Capacities (Flat Belt
          with 6-in. High Skirtboards) (TPH)  	  2-33
 2.11     Typical Production Rates (Ib/hr) and Horsepower
          for Aluminum Can Densifiers	2-43
 2.12     Typical Production Rates (Ib/hr) and Horsepower
          for Aluminum Can Flatteners	• .   '.  2-44
 2.13     Typical Production Rates (TPH)  and Horsepower
          for Glass Crushers	2-46
 2.14     Typical OCC Production Rates and Horsepower for
          Horizontal Balers 	  2-48
 2.15     Typical Densities and Weights (45"x30"x62")  for
          Baled Materials	2-49
 2.16     Material Recovery Efficiencies for Separating
          Equipment	  2-52
 2.17     Examples of Front-End Loader Capacities 	  2-56
 2.18     Approximate Range of Staffing Requirements for
          Material Recovery Facilities  	  2-58
 2.19     Manual Sorting Rates and Efficiencies 	  2-58
 2.20     Recommended Maximum Sorting Belt Widths 	  2-60
 2.21     Flat Belt Capacity	2-60
 2.22     Materials to be Collected for Recycling Newspaper,
          White Office Paper,  Corrugated Cardboard, Glass,
          Tin Cans,  Aluminum,  and Plastic 	  2-65
 2.23     Number of Full-Time Equivalent (FTE) Employees   .  2-67
 2.24     Operating Schedules of MRFs	^  . .   .  2-69
 2.25     Assumed Recyclables Composition 	  2-73
 2.26     Typical MRF Construction Costs ($/sq ft
          Floor Area	   .  2-73
 2.27     Typical MRF Floor Area Requirements by Throughput
          Capacity	2-74
                              Vlll

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                       TABLES  (Continued)
Number

 2.28     Estimated Construction Cost Range by Throughput
          Capacity  	
 2.29     Typical Unit Equipment Costs  	 . .
 2.30     Estimated Equipment Cost by Throughput Capacity .
 2.31     Estimated Total Capacity Cost Range by Through-
          put Capacity  	
 2.32     Typical MRF Labor Requirements  	
 2.33     Typical MRF Unit Operating and Maintenance Costs
 2.34     Estimated Annual O&M Costs by Throughput
          Capacity  	 •
 2.35     Waste Paper Recovery Figures  	 .
 2.36     U.S. Aluminum UBC Recycling Rates 	 .
 3.1      Sample Table of Contents for an RFP (To Receive,
          Process, and Market Household Recyclable
          Materials)  	
 3.2      Sample Table of Contents for a Proposal .  .   . .
2-75
2-76
2-77

2-78
2-80
2-80

2-81
2-85
2-90
 3-6
 3-9
                                IX

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                          ACKNOWLEDGEMENT

      This document was prepared in partial fulfillment of Contract
 68-03-3490,  Work Assignment  3-13  by  PEER Consultants,  P.C.,  under
 sponsorship  of the U.S.  Environmental  Protection Agency.   Edwin
 Earth of _ the  Center  for  Environmental  Research  Information,
 Cincinnati,  Ohio, was the Technical Project Manager responsible for
 the  preparation of this  document.   Acknowledgement  is given  to
 Steven J. Levy of the Office  of Solid Waste and Lynnann Hitchins of
 the  Risk Reduction Engineering Laboratory, who provided  guidance
 and  support.  Special acknowledgement is given to:

          Ms.  Darlene Snow  and  Mr.  Jack  Legler,  National  Solid
          Waste Management Association;
          Mr. James Meszaros and Mr.  Robert Davis;  Browning Ferris
          Industries;
          Mr. Jessie Buggs,  Prince Georges County,  MD, Residential
          Programs;
          Mr. Chaz Miller, the Glass Packaging Institute;
      -    Mr. Richard Kattar, New England, CRInc.;
          Mr. Bill Moore and  Mr. Dan Kemna, Waste Management,  Inc. ;
          and
          Mr. Mike McCullough, Ohio EPA,

all of whom  served as advisory committee members and/or technical
reviewers and contributors.

Participating in the development of this document were Dr. Joseph
T. Swartzbaugh and Mr. Donovan S.  Duvall  of PEER Consultants, P.C.,
and Dr.  Luis F. Diaz and Mr.  George M.  Savage of CALRecovery Inc!

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                            SECTION 1

                           INTRODUCTION

   The purpose  of this document is to  address  the technical and
economic aspects of material  recovery  facility (MRF) equipment and
technology in such a manner that the document may be of assistance
to solid waste planners and engineers at the local community level.
This  document points  out what technically  can  be  done,  what
material specifications  can  be achieved,  and what the different
manual and mechanical materials separation  and recovery approaches
can cost.

   This technology transfer document is a handbook intended for use
primarily (but not exclusively) by engineering or other technically
trained personnel who are engaged  in some aspect of specification,
purchase, or implementation of MRFs.   It should be  noted that this
handbook  offers  some  design-related  information,  but  is  not
intended to be a design guide.  For this document,  a MRF is defined
as a  central operation where  commingled and/or source separated
recyclables  are  processed  mechanically or manually.    Here,  a
separation  and/or beneficiation of recyclables prepares  them to
meet market  specifications for sale.   Sources  of information for
this document include the design engineering community, vendors of
equipment, and U.S. Environmental  Protection Agency (U.S. EPA) and
other federal agency documentation of process evaluations for MRFs.
Of  course,  many  presently  operating MRFs also served  as  prime
sources of  information.

   This document focuses primarily on equipment and methods for the
separation  and handling of separable or  already source-separated,
recyclable  constituents  in   the  typical  municipal solid  waste
stream.   For any single  recyclable constituent  within the solid
waste stream, alternative approaches are identified for separation
and recovery (namely,  manual versus  fully automated  versus some
kind  of  combined  approach utilizing  both  manual  and mechanical
methods) .    For  each  piece   of  equipment   in  any  approach,  the
document  addresses:   the  basis of design;  theory of operation;
sizing; and equipment  needs  such  as  shredders,  balers,  etc.  The
document descriptions include any limitations on materials in the
feed to  the equipment,  area  requirements,  building requirements,
possible  citing  and permitting requirements,   industrial health
concerns, and level of operator experience  and training needed for
proper  operation.    In addition,  economic  factors are discussed:
purchase  price;  utility  requirements;   maintenance  costs;  labor
costs;   auxiliary   equipment   purchase   needs;   sizing;   space

                                1-1

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 requirements;  redundancy  requirements;  and all aspects necessary
 for the  development of performance and equipment specifications.
 The key  focus  is  on the percent waste reduction (efficiency) and
 costs.  The document is intended to give guidance to the engineer
 as to what should be incorporated  into startup, implementation and
 acceptance testing  of any equipment and systems to be included in
 the MRF.

    MRFs are relatively new in the solid waste management field, but
 their popularity is fast increasing.  In the early 1980s, the first
 MRF was  established in Groton,  Connecticut.  This  facility was
 primitive  by  today's  standards  (not  full  scale).   The  Groton
 facility today is operational,  but  it does not accept any of the
 paper or plastic streams,  which are vital and integral components
 of any full-scale MRF.  Recently  104  MRFs  were identified in the
 U.S.  with about one-third operational, about half (51 percent)  in
 early  or   advanced   stages    of   planning,  11 percent   under
 construction,   and  4 MRFs  temporarily  shutdown  or  undergoing
 significant retrofitting (GAA,  1990) .

    An  obvious  question to many parties  is  the sudden  increased
 interest in the MRF as  an approach  to  processing  solid  waste
 Interest stems from:

        desire to reduce MSW going to  landfill;
        achieve this reduction by maximizing  recycling; and
        MRFs simplify generator requirements,  and thus  increase
        participation in recycling.

 The probable principal reason is that as solid waste disposal costs
 keep rising, a greater impetus develops in the favor  of recycling
 and the development of more MRFs. For example, when landfill costs
 were less than $10 per ton, recycling most of the waste stream was
 not economically attractive to the waste industry.   However, now
 with  tipping fees in some  areas approaching, or even exceeding,
 $100 per  ton,  waste managers are willing to spend more time and
 money  on  recycling.

    The appeal of MRFs seems to fall into three principal categories
 (Biocycle,  1990):

        the feedstock of most MRFs  is commingled recyclables;
        collection needs can be simplified,  and
        materials processed through MRFs  are more marketable.

 Citizens are encouraged to participate in a MRF operation, and as
 a result of this success of citizen participation, higher volumes
 of materials will be taken  from the solid waste stream.   Second
 because of the commingled nature of recyclables,  collection vehicle
 needs  can be  simplified.   Need  for  multicompartment vehicles is
 reduced; normally only two compartments are required.  Collection
times and costs can also be  reduced,  because less time is spent at

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the  curb  sorting  materials  or  emptying  several  containers.
Finally, most advocates believe  that  materials processed through
MRFs are more marketable.   They feel that the products of MRFs are
cleaner,  can  better  meet  industry  standards,  and  that  the
consistent volume  of material that  they  can  generate  helps  to
assure a market.

   The design of MRFs must be such that commingled recyclables can
be separated,  and the separated materials processed into marketable
commodities.   Most MRF vendors have their own basic design concept,
but they maintain the flexibility to modify their design depending
upon the  specific  requirements of the individual MRF.   In other
words, vendors can respond to the needs of  the community and try to
provide a system that will process the recyclables that are common
to that community.

   Even though many of the MRF systems are highly mechanized, there
are still many  jobs that  are best done by  humans.   For example,
nearly  all  of the  systems presently in use  hand sort  glass  by
color.   This  approach is  still  the  most  reliable way  to ensure
quality.   In  any  case,  the trade-off  between  the manual  and
mechanical MRFs is capital cost versus operating cost.  The highly
mechanical systems have a capital cost that ranges from 75 to 100
percent higher  than those for the manual  systems.   A life-cycle
cost analysis over  the operational life of the facility may show
that  the higher  operational costs  for  labor  intensive  manual
systems will become more important than the  initial higher capital
costs for mechanical  systems.  However, operating experience for
either  type  system  is  still  too limited  to allow independent
evaluation of the actual useful life of such facilities.

   The chief processing problem in any MRF  is separating the mixed
bottles and cans.  Most of the MRF systems  utilize a magnet to pull
the steel cans from the mixed materials.  Once the ferrous material
is separated it can be either shredded or baled, depending upon the
market.  The remaining fraction then includes the glass, aluminum,
and plastics.   At this point in the process,  mechanical systems can
be used to either  separate the  lighter  fraction,  aluminum and
plastics, from the glass.  The more manual systems normally utilize
workers to perform this function as well as to separate the glass
by colors.  The mechanical systems,  however, still normally use a
manual  sort  for  separating  glass  colors;  after  the glass  is
separated it can be crushed and stored for  market.  Aluminum can be
separated from the mixed materials either manually or  with aluminum
separating  equipment  such  as  eddy  current   separators.    When
plastics are accepted at  the MRF,  they  are normally separated by
type.

   While  theoretically all the materials coming into a MRF should
be recyclable,  it has been  shown  that systems  always  have some
residues.   Such residues  include contamination that is  mixed in
with the recyclables,  some nonrecoverable materials (such as broken

                               1-3

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mixed  glass  in a  commingled,  source-separated stream)  and some
materials which cannot be properly recognized by the sort mechanism
used in_the MRF.   The amount of residue depends heavily upon the
processing efficiency of the facilities,  and this is governed in
many  instances by how  well  the  community  has separated  its
recyclables,  and by what collection method is used.   For example,
if residents  persist in disposing of nonrecyclable material in the
system, then understandably the amount of residue increases.
                              1-4

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                            SECTION 2

            SPECIFIC APPROACHES TO MATERIALS RECOVERY

2.1  INTRODUCTION

     The purpose of this section is to provide the reader with a
basis for  understanding,  comparing, and  evaluating  the relative
merits of  different  approaches and solutions to  the problems of
materials recovery.  The information presented herein should be of
value to those public officials charged with review and decision-
making responsibilities as well as to those individuals responsible
for MRF planning and design.

2.2  CONCEPT DESCRIPTION

     Several approaches have been  proposed for  the recovery of
materials  from municipal wastes  over  the  past  40  years.   The
proposed schemes  range from low-technology  (i.e.,  low capacity,
relatively simple, labor-intensive,  minimum  hardware) processes to
high-technology   (i.e.,  high   capacity,   relatively _complex,
mechanical-intensive, high  capital  and operation and maintenance
costs)  concepts.     Similarly,  a  myriad  of devices   have  been
suggested  for  segregating one  or  more materials  from the waste
stream.  The decision to select one  approach versus another one is
affected by a  number of factors.   Some of these  factors include:
size;  cost;   location;  environmental   impacts;  and  economic
conditions of  the particular area.   There  are  a  large number of
conceptual designs and combinations  of equipment that could be
described, designed, and implemented.  The scope  of  this document
does  not  permit  lengthy  descriptions  of  all  possibilities.
Consequently,  the specific  approaches  and  concepts  described in
this document have been limited  to only some options.  In addition,
in order to avoid misunderstandings, definitions of important terms
used in the document are provided in Appendix A.  Descriptions of
the concepts and conditions used in the document  follow.

2.2.1  Basic MRF

     The discussion of design and operating  procedures  for MRFs is
based on a "conceptual" or  "basic" MRF.   Some variations from the
basic design are used to focus  on some  specific points.

     The  basic MRF  discussed  in this  document  is  one which is
designed, constructed, and operated  under  a few sets of  conditions.
The conditions apply to the  incoming waste  and to the  storage,

                                2-1

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processing,  and  shipping  of  the  recovered  materials.    The
conditions for each of these items are as follows:

     1.   Incoming Waste

               The  facility   receives  only   source   separated
               materials.   The  materials  are  delivered  in  two
               distinct forms.  One  stream consists  of paper and
               the other of commingled containers.

               Materials that would  be delivered  to  the facility
               in the  commingled container stream include: ferrous
               metals, aluminum,  glass,  PET,  and HDPE.

               Recyclable materials are delivered to  the facility
               via commercial  collection vehicles.

               The  facility  is  not  designed   to  accommodate
               self-haul vehicles.

     2.    Storage,  Processing,  and  Shipping

               For  each  of   the   two  incoming  fractions   of
               recyclable materials,  the facility will provide raw
               materials  storage,    means   for  separation   and
               processing,  storage   for  finished  products,   and
               means  for shipping  the finished  products in  the
               most_ appropriate  form.    A  description  of these
               conditions is presented in Figure 2-1.

          •.    The  types of finished products  from the  incoming
               paper stream include:  newspaper; mixed paper;  and
               some corrugated.

               The types of products from the commingled container
               stream  include:    ferrous  containers;   aluminum
               containers; PET bottles; HDPE containers; and glass
               jars and bottles.

              The forms and conditions in which finished products
              are  to  be  shipped   (and  thus,  the  processing
              necessary  to  produce  those  forms and to  prepare
              them for shipment)  are  dependent upon the economics
              of processing as well as upon the specifications of
              the ^markets.     Financial  viability  and  market
              requirements  are  two  major  considerations  that
              affect  the design of  a  MRF.    it  would  not  be
              financially  feasible,   for example,  to   increase
              product   quality  beyond   that  which  would   be
              necessary  to  market  the  entire  output  from  the
              facility.
                              2-2

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Currently markets do not exist for all of the materials that can be
recovered from the waste stream.  In those markets that do exist,
the market  specifications  are  varied.   Some  of the  forms  and
conditions applicable to the finished products include:

     •     Paper
               Separated by grade
               Baled (bale size  and/or  weight specified), or loose
               Dry (or may include wet)
               Clean (or contaminated or not weathered)

          Ferrous Containers
               Flattened, unflattened,  or shredded
               Labels removed (or not)
               Clean (or with limited food contamination)
          -     May or may not include bimetal
               Loose, baled, or densified into biscuit  form  with
               bale or biscuit size and/or weight specified

          Aluminum Containers
               Flattened,   shredded,   baled,   or  densified   into
               biscuit  form  with  bale  or  biscuit  size and/or
               weight specified
               Free of moisture,  dirt, steel, foil, lead, plastic,
               glass,   wood,  grease,   oil,   or  other   foreign
               substances

          PET and  HOPE  (handled  similarly)
               Baled,  granulated, or  loose
          -     Separated by  color or  type or mixed
               With or without caps

          Glass
               Separated by color and/or mixed
               Size of cullet (maximum  and/or minimum) specified
              Nature  and amount of  allowable  contamination   if
              any, specified

    •     General
              Available markets  for secondary materials typically
              specify the  means of packaging and shipping  each
              product.  The specifications depend upon location
              and end-use.  The  specifications often include the
              following:
              o
              o
              o
              o
              o
Skids or pallets
Bundles, bins, boxes, cartons, or drums
Trailer loads
Roll-offs
Rail cars
                              2-4

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2.2.2  Variations from the Basic MRF

     In the text to follow, references and comments will be made to
designs of MRFs which vary from the  "basic" MRF.  The comments are
made because there are some facilities that have been designed in
that manner.   In addition, the current climate  in  the  industry
points in those directions.  These variations include:

     1.   The facility receives only source separated materials in
          a single incoming waste stream.

     2.   The  facility  also  receives  other  source  separated
          materials  such  as  yard  waste,   wood  waste,  tires,
          corrugated,  mixed metals,  used  motor  oil,   lead  and
          batteries,   used clothing, appliances,  other  plastics,
          etc.

     3.   The facility receives mixed municipal solid waste (MSW)
          in addition to source separated materials.

     4.   The facility receives only mixed MSW.

     5.   In  addition to receiving recyclables  and/or mixed MSW
          from commercial haulers, the  facility receives mixed MSW
          from self-haul vehicles.

     6.   In addition to the recovery of  recyclables, the facility
          produces a refuse derived fuel (RDF).

     7.   In addition to the recovery of  recyclables, the facility
          prepares a compostable feedstock.

2.3  TECHNICAL

2.3.1  Waste Characterization

     In order  to properly design a MRF  it  is advisable  (in some
states necessary to comply with legislation), among other tasks, to
perform   an   analysis  of  the  waste   stream,   i.e.,   a  waste
characterization study, so that the variety and relative quantities
of  incoming materials can be identified and  determined.   Actual
field measurements are the preferred method  of waste analysis.  An
example of the composition of residential curbside recyclables is
presented in Table 2.1.  These  relative quantities are influenced,
for each community,  by various factors including:

     1.   State "bottle bills" which offer a  financial  incentive to
          the  consumer  to  return  the  container  (metal,  glass,
          and/or  plastic)  to  the  seller  thereby reducing  the
          quantity of the item(s) from the incoming waste stream.
                               2-5

-------
    TABLE 2.1.  EXAMPLE OF COMPOSITION OF RESIDENTIAL
                CURBSIDE RECYCLABLES*
             Material
% by weight
  Newspaper

  Mixed Paper

    Total  Paper

  Glass Bottles
    Clear
    Green
    Brown

  Tin Cans

  Aluminum Cans

  Plastic  Containers
    PET
    HOPE

    Total Commingled Containers

    TOTAL
    33

    41

    74



    11
     4
     4

     4

     1



     1
     1

    26

   100
* Not to be considered as either average or typical
2.   Community demographics which, as a result of its urban,
     suburban or rural nature, income level, reading habits,
     residential/commercial/industrial mix, and other factors
     increase or decrease the relative quantity of any item(s)
     in the incoming waste stream.

3.   Significant variations  in the relative  quantity  of an
     item(s) in  the  waste  stream may occur  due  to seasonal
     influences  (beverage  containers  in  resort areas,  for
     example).     In  addition,   changes  in  population,  as
     experienced at seasonal resort areas,  may have a marked
     consequence on the amounts and types of wastes generated.

4.   Community recycling education programs.
                          2-6

-------
     5.   Community mandated and enforced recycling programs versus
          voluntary recycling programs.

     6.   Relative  ease  (or  difficulty)  of  participating  in  a
          curbside recycling program.

     7.   Tipping  fee  differentials  between  those at  disposal
          facilities  and  at  a MRF  and/or the  banning of  some
          components  (e.g.,  tires,  yard  waste)  from  disposal
          facilities may bias the composition of the incoming waste
          stream at those facilities.

2.3.2  Mass Balance

2.3.2.1  Introduction and Preliminary Considerations—
     In addition  to determining the relative quantities  of the
various components in  the incoming  waste streams  in order  to
provide for  the storage,   separating,  and  processing of the raw
materials  as  well  as  for  the  handling of  residue and for the
storage and  shipping of  finished  products,  it  is  necessary  to
determine the anticipated amounts of each of these components.
The  process  by  which  this is  accomplished   is  called a  "mass
balance" analysis.  A proper mass balance  analysis  considers the
nature of the incoming waste streams, the level of technology to be
employed in the separation and processing of materials, the market
specifications for the end products,  the economic  justification for
separating and processing  materials,  and the legislated or project
designated waste diversion levels which must be met.  An important
factor to consider before  beginning  the mass balance analysis and
the  subsequent sizing  of  the MRF  and its  subsystems,   is  the
anticipated total tonnage  which the facility will  be  called upon to
handle.  It is  imperative that this total be identified and defined
as  accurately  as  possible.    Lacking  such   identification  and
definition, it is highly improbable  that the facility will perform
as designed.

Example:   A waste characterization  study and  landfill  records
indicate  that  a   community currently  generates 46,500  TPY  of
residential recyclables.  Also, through the use of pilot programs
and  or knowledge  of  experiences in  similar  communities,   it  is
estimated that 70% of the households may be  expected to participate
in a curbside collection program, then:

               46,500    TPY residential recyclables generated
               x   0.7    household participation rate
               32,500    TPY   maximum   available   for   curbside
                         collection
                               2-7

-------
 However,  it is also realized that within each participating average
 household,  only  80% of  the possible  recyclable materials  will
 actually  be placed at curbside for collection,  then:
                32,500
                x  0.8
                26,000
TPY maximum available
household internal participation rate
TPY collected at  curbside  and delivered
to facility.
     A MRF may be planned to operate 52 weeks per year,  5 days  per
week, or 260 days per year.  When a holiday falls on a weekday that
day may be made  up  on the weekend, then:
           26,000  TPY
           260  days/yr
     100 TPD collected at curbside and
     delivered to MRF.
Care must  be taken that anticipated growth in the population and
the probable corresponding change in the waste stream quantities
are allowed for.  This  does not mean that  the  facility must be
built to deal with the waste stream 20 years  from  now, but  it does
suggest that some planning needs to be carried out for that future
requirement.  Scheduled legislated waste diversion rates  also have
a bearing  on facility sizing.

     If the facility is to  be  properly  sized,  then the facility
capacity must be defined for the tipping floor as well as for the
processing  lines (schedule  for receiving  may be different from
processing).   In addition, the intended number of hours per day
(e.g., 8,12,16) and days per week  (e.g., 5,6,7) for receiving and
processing waste must be defined.  Further,  the size of the product
areas should reflect the  frequencies  of the shipping schedules.
Also,  the peak throughput  capacity of the facility must be set to
compensate  for surges  in  throughput  experienced  after special
events,  long weekends, major holidays, etc.

     From   a  purely   economic  standpoint,   it   is   generally
advantageous to utilize a  facility as continuously as possible at
its design capacity.   However,  there are  considerations  which
dictate that the facility  be operated  less than 24 hours per day
and/or 7 days per week,  including:

          traffic to and from the facility;
     *     noise;
     •     time allocated for preventive maintenance;
          loss of efficiency on  second  and third shifts (if normal
          operation depends upon two or three  shifts, there is less
          opportunity to make up for the inevitable down time) ; and
          substantial changes in waste deliveries  during the year
          (e.g., at resort areas).
                               2-8

-------
2.3.2.2  Process Flow Chart and Mass Balance—
     For the purpose  of  example,  it is assumed that the facility
will receive 100 TPD of paper  and  commingled recyclable containers
in the proportions according to Table 2.1.  The overall flows and
mass  balance  may  be  represented  on  a  summary  flow chart  as
illustrated in  Figure  2-2.  A 90% recovery rate has been assumed
which results in 10 TPD of residue to be landfilled.  The designer
should  realize  that  the  greater the   separation  of  material
categories  that occurs  at  the source,  the higher  the probable
recovery rate of those recyclables at the MRF.

2.3.3  Technology Considerations  for a Basic MRF

     The separation and processing steps required or desired at a
MRF are influenced by market requirements, by the characteristics
of the feedstock, and by  the economics associated with separation,
processing,  and transportation.   Additionally,  in  geographical
areas where labor wages are historically low and unemployment high,
there is greater reason  to  favor  a labor intensive approach than
there is in those areas where labor is scarce and labor wages high.
The total  quantity  of materials  and the  relative percentages of
material grades or categories  will have an effect upon the methods
employed for recovery and processing,  and most certainly upon the
equipment selected to recover and process the various materials.

     Tables 2.2  and 2.3 address  some  of the  more  common design
considerations   of   low-  and  high-technology   systems.     The
combinations of  low and high technologies  are virtually without
end.

2.3.4  Finished Product Specifications

     A select list of grades and definitions adapted from the Scrap
Specifications Circular  1990  as issued by the Institute of Scrap
Recycling Industries Inc. (ISRI)  is presented in Appendix B.  The
material in Appendix B provides specifications  for  tin and aluminum
cans.   Finally, Appendix  B  presents  examples  of actual  buyer
specifications for various recyclable materials.

2.3.5   Flow Chart and Mass Balance—Low Technology

     Using  the  proportions of  recyclable materials  as  shown  in
Table 2.1,  the flow chart and mass balance for the paper line are
shown in Figure  2-3.   Similarly,  Figure 2-4 is a  flow chart and
mass balance for the commingled  container  line.  With reference to
either of these two  figures the reader will note that more or fewer
separations may take place at  the  sorting  station.  In the case of
the paper line,  Figure 2-3, it  is possible that  the  only product
desired is  "mixed  paper" in which  case  it is only  necessary  to
remove whatever material is considered to be contaminating to the
product.  Or,  as markets develop or change, it may prove to be of
value to separate corrugated,  office paper, or mixed paper

                               2-9

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TABLE 2.2. COMMON DESIGN CONSIDERATION OF LOW TECHNOLOGY SYSTEMS
Material
Paper
Commingled
Containers
Basic
Feedstock
Mixed wet &
dry paper,
including
newsprint,
old corrugated
containers
(OCC), high-
grades, books,
magazines, &
contaminants
Tin, bimetal, &
aluminum cans,
plastic, & glass
containers, &
contaminants
Tipping
Floor
Handpick
OCC&
contaminants
Handpick
contaminants
Infeed
Conveyor
Handpick
OCC&
contaminants
Handpick
contaminants;
magnetic
separator for
ferrous
Sorting
Conveyor
(or room)
Handpick
OCC,
magazines,
high-grades,
mixed paper,
etc.
Handpick
plastic,
aluminum,
contaminants
Interim
Storage
In piles on
processing
floor or in
bins
In piles, bins,
or containers
Preparation
for Shipping
Ship loose, as
is, or baled
Ship loose,
as is
Finished
Product
Storage
In piles on
processing
floor, in bins,
or compacted
or baled in
transport
vehicles
In piles, bins,
containers, or
transport
vehicles
2-11
-------
TABLE 2.3. COMMON DESIGN CONSIDERATIONS OF HIGH TECHNOLOGY SYSTEMS
U»'.ttU
pjp«
tfaillttt
CommbgVxl
ConU'ntrs
IMitttl
Ferrous
(Binwul)
Petrous
(Til fens)
MaiirUI
Aluminum
Material
Ptajsc(PET)
Ibtiriil
PtiSX:
POPE)
Mjieriit
GUss
Basic
Feedstock
Mixed wot& dry
papor. including
novrtpal, old
corrugated con-
UinefstOCq,high
grades, books.
magazines &
contaminants
Btste
Feedstock
Tn. bimetal, &
aluminum cans.
plastic and gbss
containers, &
contaminants
Sort
Mania! separation
ol tin cans and
birwu! (7 required)
Manual separatnn
ol (in cam and
b'nwul {I required)
Septraie
Eddy current
apparatus
separates
alurnintjm tram
plane
Sort
Manual son ol
PET, HOPE, other
Sort
Manual sort ol
PET. HOPS, othaf
Sort
Tipping
Floor or
Sptclal Station
HandpkfcOCC
& conuminams
assisted by a
grapploUor
Iron-end loader
Tipping Floor
or Sptclal
SUilon
Handpfck
conuminants
Bait
Vfthauto-tio
babr
With aixo-tio
bater
Flattin
Wihcan
llattener
Interim
Storage
In overhead
hoppers
Interim
Storage
In overhead
hoppers

Optical automatic son or hand sort by
color
lnle«d Trommel
Conveyor
Grapple ol front- Separates
end loader oversize OCC
S/or newspaper
from mixed
paper
Infeed Conveyor
Handp'ck contaminants; magnetic
separator lor ferrous
Biscuit Shred
With can
densferand
palletize
With can With can
denslierand shredder
paEetize
Store Bale
Pneumat'eaBy With auto-tie
convey to baler
outside trans-
pon vehicte
Perforate
Drop from overhead hopper or
pneumaticafty convey to perforator
Granulate
Drop from overhead hopper or
pneumatically convey to granulator
Crush
To meet market specifications
Sorting Interim Preparation Finished
Conveyor Storage for Shipping Product
(or room) Storage
Handpkk Accumulated in Auto-tie baler In slacks or
remaining OCC, bins or bunkers bales on
magazines, high- before being processing floor
grade. & mixed selectively or stacked in
paper, etc. conveyed to transport vehicle
baler
Screen Traveling Chain Curtain
Broken glass recovered as undersized Separate aluminum and plastic from
materials glass
Air Classify Store
In stacks on processing floor,
outdoors, or in a transport vehicle
To remove Convey shredded ca ns u outside
labels transport vehicle, or bales or biscuits
in stacks on processing floor,
outdoors, or in a transport vehicle
Store Biscuit Store
In bales on Compress 'm a In stacks on the processing floor or
processing floor densifier and outdoors or in a transport vehicle
or outdoors palletize
Bale Store
Mechanically or pneumatically from In stacks or bales on processing Ikwr
perforator to auto-tie baler or outdoors in transport vehicles
Bale Store
Mechanically or pneumatically convey Granulated in gaylords on processing
from hopper to auto-tie baler floor before loading into transport
vehicle, baled in stacks on processing
floor or outdoors in transport vehicles
Upgrade Store
Remove paper labels, metal (ids, & In bunkers lor loading by front-end
other contaminants by trammel and/or loader, or in overhead bins for
air classifier selectively conveying to transport
vehicles
2-12
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