EPA/600/R-94/165
September 1994
COST EVALUATION OF AUTOMATED AND MANUAL
POST-CONSUMER PLASTIC BOTTLE SORTING SYSTEMS
by
Jonathan Burgiel
Wendy Butcher
Ray Halpern
Dan Oliver
Pat Tangora
R. W. Beck
Orlando, Florida 32803
and
Solid Waste Association of North America
Silver Spring, Maryland 20910
Cooperative Agreement No. 81823 8
Project Officer
Diana R. Kirk
Waste Minimization, Destruction, and Disposal Research Division
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
RISK REDUCTION ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
Printed on Recycled Paper
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DISCLAIMER
The information in this document has been funded wholly or in part by the United States Environmental
Protection Agency, under Cooperative Agreement No. CR-818238 to the Solid Waste Association of North
America (SWANA), and by the American Plastics Council (APC). The document was prepared by R.W. Beck.
Facility specific cost and operating information furnished by the study facilities was not independently
verified, and R. W. Beck gives no guarantee of the accuracy of this information.
Mention of trade names or commercial products does not constitute endorsement or recommendation for
use.
11
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FOREWORD
Today's rapidly developing and changing technologies and industrial products and practices frequently
cany with them the increased generation of materials that, if improperly dealt with, can threaten both public
health and the environment. The U.S. Environmental Protection Agency is charged by Congress with protecting
the Nation's land, air, and water resources. Under a mandate of national environmental laws, the agency strives
to formulate and implement actions leading to a compatible balance between human activities and the ability of
natural systems to support and nurture life. These laws direct the EPA to perform research to define our
environmental problems, measure the impacts, and search for solutions.
The Risk Reduction Engineering Laboratory is responsible for planning, implementing, and managing
research, development and demonstration programs to provide an authoritative, defensible engineering basis in
support of the policies, programs, and regulations of the EPA with respect to drinking water, wastewater,
pesticides, toxic substances, solid and hazardous wastes, and Superfund-related activities. This publication is one
of the products of that research and provides a vital communication link between the researcher and the user
community.
This publication is part of a series of publications for the Municipal Solid Waste Innovative Technology
Evaluation (MITE) Program. The purpose of the NOTE program is to: 1) accelerate the commercialization and
development of innovative technologies for solid waste management and recycling, and 2) provide objective
information on developing technologies to solid waste managers, the public sector, and the waste management
industry.
E. Timothy Oppeh, Director
Risk Reduction Engineering Laboratory
iii
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ABSTRACT
This project evaluates, on the basis of performance and cost, two automated BottleSort® sorting
systems for post-consumer commingled plastic containers developed by Magnetic Separation Systems. This
study compares the costs to sort mixed bales of post-consumer plastic at these two facilities with similar
costs developed from a study at a manual sorting facility.
Three months of historical operating data was provided by each facility. This data, along with data
obtained from three-day site visits to each facility, provided the basis for the economic analysis and
comparison among the three facilities. Analysis of product output quality, also obtained at each facility
during the site visits, was the basis for the system performance analyses.
The quality of the materials produced at each facility was similar. The market into which the
plastic is being sold determines the specifications for purchase; each facility provided sufficient sorting to
meet such requirements. Both facilities utilizing the automated sorting systems produced material at lower
costs than the manual sorting facility, based on overall sorting costs per pound of material generated for
sale.
This work was submitted by R.W. Beck to the Solid Waste Association of North America in
fulfillment of Cooperative Agreement No. CR-818238. This report covers a period from April, 1994 to
August, 1994.
IV
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CONTENTS
Disclaimer ii
Foreword iii
Abstract iv
Figures viii
Tables ix
Acknowledgments x
Section 1. Introduction 1
Purpose and Background 1
Project Overview and Key Assumptions 1
Section 2. Key Findings 3
Sections. Sorting Systems Description 4
First Generation MSS BottieSort® Facility 4
Background 4
Sorting Staff' 4
Material Produced by the Sorting Function 4
Equipment and Layout 5
Second Generation MSS BottieSort® Facility 7
Background 7
Sorting Staff 7
Material Produced by the Sorting Function 7
Equipment and Layout 7
Manual Sort Facility 9
Background 9
Sorting Staff 9
Material Produced by the Sorting Function 9
Equipment and Layout 10
Section 4. Economic Comparison of Sorting Systems 12
Introduction 12
Cost Included in the Analysis 12
Cost Analysis Methodology 13
Data Request 13
Spreadsheet Model 13
Review Results with Facility Operators 14
Assumptions 14
Facility Sorting Capacity and Material Composition 14
Labor Rates, Residue Disposal Rates,
and Building Lease Rates 15
Operating Schedule 15
Equipment Capital Cost 15
Maintenance, Supply, and Utility Costs 15
Labor Requirements 16
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Sort Line Space Requirements 16
Equipment Life 16
Cost of Capital 16
Adjustments for System Differences 16
Operating Practices 16
Quality/Purity of Sort Performed 17
Length of Operating History 17
Not an Audit 18
Survey Limitations and Other Considerations 18
Limited Study 18
One Operating Scenario 18
New Systems 18
Changing Feedstocks 18
Changing Regulations 18
Cost Comparison Results 19
Fixed and Variable Operating Costs 22
Sorting Costs by Resin Type 23
Cost Analysis Findings 27
Sections. Field Test Analyses 28
Overview 28
Normal Operations Tests 28
System Definitions 29
Test Parameters 29
Test Results 30
Test Comparison 33
Item Count Machine Accuracy Test 35
System Definitions 35
Test Parameters 35
Test Results 35
Test Comparison 37
Bottle Weight Machine Accuracy Test 38
System Definition 39
Test Parameters 39
Test Results 39
System Sort Quality Testing 41
System Definition... 41
Test Parameters 41
Test Results 41
Test Comparison 41
Field Test Results... 45
VI
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Technical Appendices (data request form mailed to facility operators, economic model spreadsheet, facility test
plans, and raw field test data collection sheets) available upon request at (513) 569-7674.
vu
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FIGURES
Number page
1 First Generation MSS Facility—Illustration of Sorting Process 5
2 Second Generation MSS Facility—Illustration of Sorting Process 8
3 Manual Sort Facility—Illustration of Sorting Process 10
4 Cost Comparison Results 21
Vlll
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TABLES
Number Page
1 Comparison of Key Input Variables by Facility 20
2 Cost Comparison of First and Second Generation MS S Facilities to Manual Sort Facility 21
3 Estimated Fixed and Variable Operating Costs for Sorting Commingled
Plastic Bottles 22
4 Breakdown of Capital and Labor Requirements by Resin Type 24
5 Breakdown of Resin Specific Annual Amortized Capital and Operating Costs 25
6 Sorting Cost by Resin Type 26
7 First Generation MS S Facility—Normal Operations Test Summary 30
8 Second Generation MS S Facility—Normal Operations Test Summary 31
9 Manual Sort Facility—Normal Operations Test Summary 32
10 Comparison of Historical Operating Data to Normal Operations Test 34
11 First Generation MS S Facility—Item Count Machine Accuracy Test Summary 36
12 Second Generation MS S Facility—Item Count Machine Accuracy Test Summary 37
13 Comparison of Item Count Machine Accuracy Tests 38
14 Second Generation MSS Bottlesort® Facility—Bottle Weight Machine
Accuracy Test Summary 40
15 First Generation MSS Bottlesort® Facility—System Sort Quality Test Summary 42
16 Second Generation MS S Bottlesort® Facility—System Sort Quality Test Summary 43
17 Manual Sorting Facility—System Sort Quality Test Summary 43
18 Comparison of Overall Product Quality 44
IX
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ACKNOWLEDGMENTS
This project was funded under the U.S. EPA's Municipal Innovative Technologies Evaluation
(MITE) Program, and by the American Plastics Council. Project management was provided by the Solid
Waste Association of North America (SWANA). The EPA Project Coordinator was Diana Kirk, and
APC's Project Manager was Peter Dinger. SWANA's Project Officer was Charlotte Frola.
The principal system developer was Garry Kenny of Magnetic Separation Systems, Inc. in
Nashville, Tennessee.
R. W. Beck evaluated the technology and prepared the report. The principal authors were
Jonathan Burgiel, Raymond Halpern, and Daniel Oliver, who also served as R. W. Beck's Project Manager.
Report reviewers included Diana Kirk of the U.S. EPA, Charlotte Frola of SWANA, Peter Dinger of APC,
Garry Kenny of MSS, and each facility's chief operating officer.
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SECTION 1
INTRODUCTION
PURPOSE AND BACKGROUND
Differences in plastic resin properties dictate that post-consumer plastic containers be separated by resin
type before they are processed into a form that can be used as a substitute for virgin resin. Sorting post-consumer
plastic bottles has been identified as one of the most costly elements of preparing plastic containers for recycling.
As a result, U.S. post-consumer plastic reclaimers have been placing additional emphasis on improving the cost
effectiveness of their sorting operations. Recently, several plastics reclaimers have installed automated sorting
equipment with the goal of reducing their sorting costs. In addition, automated sorting equipment holds the
promise of reducing sorting errors, to which manual sorting has been susceptible.
The purpose of this study is to compare, on the basis of performance and cost, the BottleSort® automated
sorting system by Magnetic Separation Systems, Inc. (MSS) to the more traditional manual sorting system. This
study was jointly funded by the U.S. Environmental Protection Agency (EPA), through a grant to the Solid
Waste Association of North America (SWANA), and the American Plastics Council (APC).
PROJECT OVERVIEW AND KEY ASSUMPTIONS
The primary focus of this study is the evaluation and comparison of the sorting operation at three
commercial plastic bottle recycling facilities, in terms of performance and cost effectiveness. The first facility
utilizes a first-generation MSS BottleSort® automated bottle sorting system (first generation MSS facility), the
second facility utilizes a second-generation MSS BottleSort® automated bottle sorting system (second generation
MSS facility), and the third facility utilizes a manual sorting system (manual sort facility).
Three months of continuous operating data were requested of each facility to perform the economic
comparison. Individualized field test plans were prepared to gather data for evaluation and comparison of the
three facilities. Field testing was intended to:
• Provide an understanding of the operational similarities and differences between each facility.
• Confirm the historical operating data provided by each facility.
• Provide information and data not normally tracked by the facilities.
• Serve as a "snapshot" of each facility's operations.
The on-site implementation of each test plan was supervised by R. W. Beck personnel. The test duration
at each facility was approximately three days.
The historical operating data received from each facility, combined with the data gathered during the
field testing, were compiled and analyzed. Certain key assumptions were adopted for this study to control
variability in the results due to factors unrelated to sorting technology and to allow for meaningful comparisons
between facilities. These assumptions included:
• Normalized labor rates for similar positions at each facility, regardless of geographic location.
• Normalized disposal costs, regardless of geographic location.
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Normalized building lease costs (so that costs differences reflect only the difference in actual
space for automated versus manual sorting).
Staffing, building, land, and equipment not attributable to sorting were omitted from the
analysis.
Similar feed stream (similar types and proportions of plastic bottle materials coded #1-7).
Normalized input volumes.
Normalized operating hours/day.
Capital costs for sorting equipment were amortized over the equipment's useful life (7 to 10
years) at 8 percent.
General and administrative costs were omitted from the analysis.
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SECTION 2
KEY FINDINGS
Analysis of the data provided by each facility and generated from the on-site testing at each facility showed the
following:
• The MSS facilities were found to be more cost effective than the traditional manual sort
system analyzed. The cost comparison results indicate that the first generation MSS
facility has a 0.7 cents per pound or 15 percent cost advantage over the manual sort
facility while the more sophisticated second generation MSS facility has a 1.1 cents per
pound or 24 percent cost advantage.
• All three facilities produce high quality plastic materials meeting or exceeding market
specifications for sale. However, PET sorted at the manual sort facility must be sold in
whole bottle form to customers with automated PVC sorting equipment in order to achieve
industry acceptable standards for PVC content; the MSS BottleSort® systems already
operated such automated PVC sorting equipment prior to grinding. An adjustment was made to
the cost comparison discussed above to compensate for this difference in operating practices.
• Other improvements which have been identified may potentially increase the cost savings of the
second generation MSS facility over the manual sort facility. These include installation of a
trash conveyor to remove trash from the sorting lines directly to a trash compactor, and
extension of the PVC sorting line to allow for metering of the material ejected onto that line.
These improvements could reduce the second generation MSS facility's labor requirements by
as much as one laborer's time per shift. This would increase the cost advantage over the manual
sort facility by approximately another 4 percent, to approximately 28 percent.
• The increased amortized equipment and maintenance and repair costs experienced by the
MSS facility operators were more than offset by the labor cost savings resulting from the
use of the MSS BottleSort® system.
• Despite the labor cost savings resulting from the use of the MSS BottleSort® system, labor
requirements continue to be a significant budget item at the MSS facilities. Based on the
results of the analysis, labor costs represented 56 percent and 61 percent of overall annual
sorting costs for the first and second generation MSS facilities versus the 83 percent
estimated for the manual sort operations.
• The second generation MSS BottleSort® system appeared to more accurately eject correct
materials by resin/color than did the first generation system, based on the on-site tests
conducted.
• A variation in commingled bale composition occurs on a lot-by-lot basis for material collected
by a single community.
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SECTION 3
SORTING SYSTEMS DESCRIPTIONS
This section describes the general operations of each of the three facilities tested in this study.
FIRST GENERATION MSS BOTTLESORI* FACILITY
Background
This facility has been in continuous operation for twelve years. The facility operates 7 days per week,
and operates commingled bale sorting operations in two shifts from 4:00 am to 2:30 p.m., and 2:30 p.m. to 1:00
a.m., Monday through Thursday.
Sorting Staff
The sorting function employs 6 full-time and 1 part-time staff per shift. Typically, the facility employs
five inspectors, one balebreaker operator/supervisor (who also assists as a "floating" inspector as time permits),
and a mechanic (part-time) per shift.
Material Produced by the Sorting Function
This facility receives on average approximately 24 tons of baled, commingled plastic bottles per day
(based on 4 days per week). During a recent nine-hour operating test, the facility processed an average of 4,620
pounds of material per net hour of operation (excluding downtime due to breaks and equipment malfunction).
Alternatively, based on three months of actual operating data provided by the facility operator, the facility
processed an average of 2,400 pounds of material per hour (including downtime due to breaks and equipment
malfunction).
Sorted post-consumer plastic materials produced by the sorting function of this facility include:
• Clear PET
• Green PET
• Dairy "A" (higher quality natural HOPE)
• Dairy "B" (lower quality natural HOPE)
• Mixed color HOPE
• PP
• PVC
Approximately 2,500 pounds per month of used baling wire is sold for scrap. Additionally,
approximately 60 tons per month of trash and other residue (about 16 percent of total input) from the sorting
process are collected for disposal.
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Equipment and Layout
The sorting function at this facility utilizes a first-generation MSS BottleSort* system, which has been
operating for approximately 3 years. All the sorting and processing equipment is housed in a brick building
measuring approximately 60,000 square feet. The area dedicated to the debaling/sorting function is
approximately 9,600 square feet. Figure 1 illustrates the sorting process at this facility.
Figure 1
FIRST GENERATION MSS FACILITY
ILLUSTRATION OF SORTING FHOCESS
= Inspector
= Balebreaker Operator/Supervisor
(also assists as a floating*
inspector as time permits)
1 st Ejection Point
Clear & Green PET
and
PVC
Primary
Detection
Lines
2nd Ejection Point
Natural HOPE
and
PP
Trash
3rd Ejection Point AH remaining
Mixed Color HOPE containers are
(Not fully utilized) diverted °"to
this line
The basic operating layout of the sorting function begins at the bale table, where the baled, commingled
plastic containers are first deposited by a forklift. The bale wires are cut and removed by the bale breaking
personnel. The bales are conveyed to a debaler, which breaks the bales apart. The material then fells into a
declumper to reduce clustering of bottles. A cleated, inclined metering conveyor feeds the bottles over a vibrating
screen for removal of small contaminants, such as caps and lids, to one of four separate primary detection lines
for scanning by the BottleSort* system. Oversized bottles (mostly natural HDPE and PP) are removed by the
machinery and run through the sorting system at a later time. Oversized bottles are fed directly to the detection
lines due to their tendency to tumble down the feed conveyor.
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The BottleSort® system features four (4) detection sensors (one for each of the primary detection lines)
which utilize X-ray radiation to compare the transmitted light spectrum from an incoming bottle with spectra
from various resin types that are pre-programmed into the computer's memory. When a match is detected, the
computer is programmed to engage air jets that eject the bottle onto the appropriate sorting line conveyor. The
first ejection point ejects PET and PVC bottles from the commingled bottle stream to the first manual inspection
line. The second ejection point ejects natural HDPE and PP bottles from the bottle stream onto the second
manual inspection line.
Additionally, this system has a third ejection point designed to eject mixed color HDPE and other opaque
bottles onto the third sorting line. However, it was found that when this ejection point was used according to
design, approximately 10 percent of the bottles were not identified by the BottleSort® sensors and passed by this
ejection point, falling off the end of the line into gaylords. Since the material in these gaylords required further
manual sorting, diverters have been installed at the third detection unit to remove all remaining bottles onto the
third sorting line. Because the sensors continue to identify the mixed color HDPE in the bottle stream, the air
ejection system at the third ejection point is still active. These air blasts aid in preventing the diverters from
becoming clogged. Some trash escapes past the diverters and falls off the end of the primary detection lines into
trash cans.
Material ejected at the first ejection point is carried away from the BottleSort® system on the first sorting
line conveyor system for manual sorting and quality control. The first sorting line has two inspectors stationed
along the conveyor system. The first inspector is responsible for removing green PET, which is deposited into a
nearby chute, with no further inspection before being ground. Additionally, this inspector removes any natural
and mixed color HDPE and PP bottles mistakenly ejected at the first ejection point. A second chute is used by the
inspector to return these bottles to the third manual sorting line (ejection point for mixed color HDPE).
Therefore, any material remaining on the conveyor after passing this inspector typically consists of clear PET,
PVC, and residues. The conveyor system continues past an automated MSS BottleSort® PVC detection and
ejection unit. A second inspector subsequently utilizes a "black light" to isolate all remaining PVC materials,
which are manually placed into a designated gaylord for recovery. This second inspector also deposits residue to
a trash container. The clear PET remaining on the conveyor system is then ground.
Material ejected at the second ejection point is carried away from the BottleSort® system for manual
sorting and quality control by one inspector dedicated to this line. This inspector removes any PET from the
stream and places it onto a conveyor that returns the bottles to the first sorting line. Additionally, any lower
quality HDPE natural bottles (i.e., with caps, dirt, etc. and referred to as Dairy "B") or mixed color HDPE bottles
are manually returned to the third sorting line. PP bottles are manually removed and placed in designated
gaylords, and residues are placed into trash cans. The remaining high-quality natural HDPE bottles (i.e.,
relatively clean with no caps and referred to as Dairy "A") then continue on the conveyor to be ground.
All material remaining on the four primary detection lines is diverted from the BottleSort® system at the
third ejection point and is conveyed away for manual inspection on the third sorting line. Two inspectors are
dedicated to the third sorting line. PET is removed and placed onto a conveyor that returns the bottles to the first
sorting line, PP is placed into gaylords, and residues are placed into trash cans. Mixed color HDPE is placed
onto a parallel conveyor, where the material is sent to the grinder. Remaining natural HDPE bottles continue on
the conveyor to a grinder. Generally, the two inspectors jointly share the responsibility for performing these
activities.
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SECOND GENERATION MSS BOTTLESORT* FACILITY
Background
This facility has been in continuous operation since September 1993. The facility operates a day shift
from 7:00 a.m. to 3:30 p.m., Monday through Friday, and an evening shift from 5:30 p.m. to 2:00 a.m., Sunday
through Thursday. No processing occurs at the facility from Friday afternoon through Sunday evening.
Sorting Staff
The sorting function of this facility employs 10 full-time and 1 part-time staff per shift Typically, the
facility employs eight inspectors (including one floating inspector), a supervisor, a balebreaker operator, and a
mechanic (part-time) per shift.
Material Produced by the Sorting Function
This facility receives on average approximately 29 tons of baled, commingled plastic bottles per day
(based on 5 days per week). During a recent eight-hour operating test, the facility processed an average of 4,827
pounds of material per net hour of operation (excluding downtime due to breaks and equipment malfunction).
Alternatively, based on three months of actual operating data provided by the facility operator, the facility
processed an average of 3,600 pounds of material per hour (including downtime due to breaks and equipment
malfunction).
Sorted post-consumer plastic materials produced by the sorting function of this facility include:
• Clear PET
• Green PET
• Natural HOPE
• Mixed color HOPE
• PVC rich material
Approximately 4,000 pounds per month of chopped baling wire is sold for scrap. Additionally,
approximately 60 tons per month of trash and other residue (about 10.5 percent of total input) from the sorting
process are collected for disposal.
Equipment and Layout
All the sorting and processing equipment is housed in a metal building measuring approximately 40,000
square feet. This facility utilizes a second-generation MSS BottleSort* system that has been in place for 9
months. The area dedicated to the sorting function is approximately 9,000 square feet. Figure 2 illustrates the
sorting process at this facility.
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Figure 2
SECOND GENERATION MSS FACILITY
ILLUSTRATION OF SORTING PROCESS
Inclined
Metering Singulation
Conveyor Lin€S
1$t Eject ion Point 2nd Ejection Point 3rd Ejection Point 4th Ejection Point
PVC/Trasri Clear PET Green PET Natural HOPE
All remaining
containers are
deposited onto
this line
Inspector
Balebreaker Operator
Supervisor
PVC RICH|
(Baled)
[CLEAR PET|
(Ground)
(Ground)
NATURAL
HOPE
MIXED
COLOR HOPE
(Ground)
(Ground)
Like the first generation MSS facility, the basic operating layout of the sorting function begins at the bale
table, where the baled, commingled plastic containers are first deposited by a forklift. The bale wires are cut and
removed by the bale breaking personnel. The bales are conveyed to a debater, which breaks the bales apart. The
material then fells into a declumper to reduce clustering of bottles. A cleated, inclined metering conveyor feeds
the bottles over a screen for removal of small contaminants, to one of four separate primary detection lines for
scanning by the BottleSort* system.
Like the first generation MSS facility, the BottleSort* system at this facility features four (4) detection
sensors, one for each primary detection line, except that four (4) PVC detection units are included in each primary
sorting line. Also, the BottleSort* system at this facility utilizes four ejection points. The first ejection point is
designed to eject PVC. The PVC detection settings on the BottleSort* system can be set to various sensitivities,
dependent on the operator's tolerance for potential PVC contamination in the other material streams. This facility
has decided to set the sensitivity at a level high enough to ensure that the vast majority of PVC will be ejected at
this point. Of the 6.8 percent of input material ejected on the PVC line during the bottle weight machine accuracy
test (see Table 15), it was estimated that 2 percent was PVC and 4.8 percent was primarily loose and "clumped"
HOPE and PET bottles and metal that the sensor detected as PVC. The second, third, and fourth ejection points
are set to eject clear PET, green PET, and natural HDPE. Any remaining material (designed to be mostly mixed
colored HDPE) travels to the end of the detection lines.
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Material ejected at the first ejection point (PVC) currently is not being subjected to any further sorting.
The facility operator currently has a market for this PVC-nch material and does not feel the cost of adding an
inspector on this line is economically worthwhile. Material ejected at the other ejection points and material
remaining at the end of the primary detection lines are manually sorted to remove trash or material that was
incorrectly ejected. Seven inspectors on these sorting lines transfer incorrectly ejected bottles to the appropriate
line through a cross-conveyor unit. Additionally, trash (and other non-processable material) are removed and
placed in trash containers beside each inspector. There are two inspectors located on the clear PET line, one on
the green PET line, two on the natural HOPE line, and two on the mixed color HDPE line. A secondary PVC
detection unit is located on the clear PET line just prior to granulation to further reduce the potential for PVC
contamination. Finally, the sorted PET and HDPE streams are transported by inclined conveyors to grinders.
The eighth "floating" inspector assists the other inspectors when required as well as with the removal of
trash from the containers along the sorting lines.
MANUAL SORT FACILITY
Background
This facility has been in continuous operation since 1990. The facility normally operates a day shift
from 7:00 am to 3:30 p.m. and evening shift from 3:00 p.m. to 11:00 p.m. Monday through Friday. The facility
utilizes a manual sorting separation system. The shifts overlap somewhat to allow for cleanup time and provide
for a smooth transition between shifts.
Sorting Staff
The sorting function of this facility employs about 14 full-time and 1 part-time staff per shift. Typically,
the facility employs approximately nine sorters, three inspectors, a supervisor, a balebreaker operator, and a
mechanic (part-time) per shift.
Material Produced by the Sorting Function
This facility receives on average approximately 24 tons of baled, commingled plastic bottles per day
(based on 5 days per week). During a recent eight-hour operating test, the facility processed an average of 3,915
pounds of material per net hour of operation (excluding downtime due to breaks and equipment malfunction).
Alternatively, based on three months of actual operating data provided by the facility operator, the facility
processed an average of 3,000 pounds of material per hour (including downtime due to breaks and equipment
malfunction).
Sorted post-consumer plastic materials produced by the sorting function of this facility include:
• PET (clear and green, not separate)
• Natural HDPE
• Mixed color HDPE
• PVC
• PP
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Approximately 3,000 pounds per month of chopped baling wire is sold for scrap. Additionally,
approximately 50 tons per month of trash and other residue (about 10.5 percent of total input) from the sorting
process are collected for disposal.
Equipment and Layout
The sorting and processing equipment is housed in several concrete warehouse buildings measuring
approximately 400 feet by 200 feet The area dedicated to the sorting function is approximately 10,000 square
feet Figure 3 illustrates the sorting process at this facility.
Figures
MANUAL SORT FACILITY
ILLUSTRATION OF SORTING PROCESS
Vibratory
Screen
Inclined
Conveyors
/o
00
"i i
* i
£ f
ft
dear*
Cffc^n
PET
•*> 1
Ik 1
c f
5
Mixed
Color
HOPE
s |
* 1
cf
30
PVC
(
Trash
V
Conveyer
to Trash
Compactor
(+) = Manual Sorter
(££) = Inspector
: Batebreaker
•Supervisor
The basic operating layout of the sorting function begins at a staging area where the commingled plastic
materials are first deposited by a forklift. While this facility has automated bale breaking equipment, it was found
mat the current machine is not capable of sufficiently breaking the bales. Therefore, this facility currently utilizes
a manual system to break the bales. The bale wire is cut, and the forklift is used to drop the bales back to the
floor. This process breaks up the bales somewhat, and the material is pushed into a pit. Bale breaking personnel
manually break the bales further apart, to separate the bottles as much as possible. An inclined conveyor carries
material out of the pit and transports it over a vibratory screen, where small contaminants such as caps and lids
fall through the screen and further separation of any clumped bottles occurs. Another inclined conveyor
transports the commingled materials from the vibratory screen to the main sort conveyor, situated approximately
20 feet above the floor of the facility.
Sorting personnel on either side of the main sort conveyor remove their assigned materials and toss them
into chutes which deposit into one of nine large (60 cubic yard) holding bins. Each bin is open-topped at the main
conveyor level, and has a conveyed bottom with an outlet at floor level. These bins offer the flexibility to store
10
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different materials, depending on the composition of die incoming feedstock. Ten sorters are typically stationed
along the elevated manual sorting conveyor. Three sorters initially remove natural HOPE from the belt, placing
the material into one of two dedicated storage bunkers for natural HDPE. Two sorters are then responsible for
separating out PET (both green and clear) into the third bunker, where the material is later removed and baled.
One sorter separates out mixed color HDPE into a bunker, while the remaining three sorters are responsible for
recovery of the PP and PVC bottles and any remaining PET and HDPE containers. A single return line for PET
is located underneath the main sorting line for use by the sorters for recovery of PET that is not removed by the
PET sorters. Therefore, as the incoming material stream progresses toward the end of the conveyor, more and
more product material is removed, until nothing but trash and undesirable materials remain. The trash is
conveyed off the end of the main conveyor to a trash compactor for disposal.
Sorted materials are collected in the holding bins until there is enough material to process. The bins are
opened from the ground level, and their contents discharged onto adjacent conveyors. Inspectors at this point
check for any "mistake" bottles not belonging to the sorted material type. These mistakes are put into gaylords
for resorting. Correctly sorted materials are conveyed, depending on material type, to either a granulator for
further processing, or to a baler for baling.
11
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SECTION 4
ECONOMIC COMPARISON OF SORTING SYSTEMS
INTRODUCTION
As mentioned earlier in this Report, a cost comparison of the three test facilities was performed to
determine the relative cost effectiveness of each facility's sorting operation, particularly focusing on the relative
cost differences associated with the manual versus automated sorting of commingled plastic bottles. For
purposes of this cost analysis, sorting was defined as the process of physically separating a stream of commingled
plastic bottles by resin type as well as the removal of trash from a facility's incoming stream of baled commingled
plastic bottles.
The sorting function typically included debaling the commingled bales of post-consumer plastic bottles
and separating this mixed bottle stream into natural HDPE, mixed-color HOPE, green and clear PET, PP, and
PVC bottles using conveyors and automated and/or manual sorting. After sorting, the bottles were typically
conveyed either directly to a baler or granulator or to holding bunkers for later baling or bulk granulation.
For the three month historical period analyzed, the three facilities processed materials from different
post-consumer sources. Yet, based on the breakdown of the sorted output, the composition of materials
processed was generally similar.
The remainder of this section of the Report is organized into the following areas:
• Costs included in the analysis;
• Cost analysis methodology;
• Key assumptions used in the analysis;
• Limitations of the analysis; and
• The cost comparison results.
COSTS INCLUDED IN THE ANALYSIS
The following costs were included in the analysis. Because technologies varied at each facility, not all
costs applied to all facilities.
Sorting costs included capital, operating, and maintenance costs for all activities from the point at which
bales were placed on the bale table for bale breaking to the point at which sorted bottles were ready to be fed to
the baling or granulating function or to holding bunkers. These sort related costs included:
• Labor costs (with taxes & benefits) for manually sorting materials from belts,
debaling/declumping materials for processing, controlling sorting equipment, maintaining
sorting equipment, and supervising sorting operations;
• Depreciation and amortization of debalers/declumpers, screens, inclined feed conveyors,
horizontal sorting conveyors, bottle singulating conveyors, automated sorting systems, and take
away conveyors for quality control inspection and sorting, including costs for equipment
engineering, installation, and startup;
12
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Pro-rata share of facility disposal costs;
Pro-rata share of facility electricity costs;
Pro-rata share of building lease costs;
Gloves, safety glasses, and other protective equipment used by sorting personnel; and
Replacement parts and samples such as bearings, belts, motors, x-ray tubes, sensors, and motor
controls associated with the sort function.
Assumptions used in this analysis regarding labor rates, building lease rates, and disposal rates were
based on averages of actual cost data provided by the three facilities to remove regional cost differences, thereby
allowing for a more accurate comparison of each facility's sorting operation cost
COST ANALYSIS METHODOLOGY
Each of the following steps were performed in preparing the cost analysis and are described in separate
paragraphs which follow below.
• Preparing the data request;
• Spreadsheet modeling of the data obtained from each facility; and
• Allowing each facility to review its own cost analysis for additions/deletions or modifications.
Data Request
A data request form was designed to gather sorting related operating cost information for the three month
period ending June 30,1994. The data request was sent to each facility operator during the study to complete and
mail back to R. W. Beck. Sorting related information requested in the data request consisted of the following:
Sort line operating schedule
Sort line related utility costs
Input feedstock quantities
Sort line output and waste quantities
Sort line related waste handling costs
Fixed equipment list and capital costs (sort related)
Sorting equipment operation, maintenance & supply costs
Building space requirements for sort line
Sort line personnel
Random incoming lot data
Spreadsheet Model
Using the data obtained as a result of the data request as well as operating data obtained during the site-
tests, R. W. Beck developed a computer spreadsheet that evaluated sorting related costs at the three facilities.
The spreadsheet addresses:
• The amount of material handled (both input and output) as part of the sorting function
13
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• Residue disposal amounts and associated costs
• Equipment capital, operations, and maintenance costs
• Engineering, installation, and startup costs
• Supplies
• Building lease costs
• Utilities
• Labor and benefits
Since the cost analysis was intended to focus specifically on comparing the cost of automated and
manual sorting technologies, the sorting function was isolated from other operating functions that had the
potential to impair the cost comparison. As a result, the cost analysis focused specifically on the equipment and
activities associated with debating, declumping and screening material, and sorting material along the horizontal
conveyors at the manual sort facility and the comparable MSS BottleSort* equipment and activities at the
automated sorting facilities.
The analysis did not include costs for purchased materials, inclined conveyors following the sorting
function (typically feeding grinders or baling equipment), storage bunkers, or revenues from the sale of finished
products. The cost analysis also excluded administrative and general expenses.
Sorting costs generally were calculated as the facilities' actual cost of sorting as practiced at the facility,
although labor rates, building lease rates, and disposal rates were averaged for the three facilities to compensate
for regional cost differences in these input values. Operating schedules were also standardized (two eight hour
shifts per day, seven days per week) to remove potential cost advantages for a facility that may arise purely as a
result of the number of hours operated per week.
Review Results with Facility Operators
The individual spreadsheet analysis and results for each participating facility were provided to each
respective operator for their review. Comments provided by the facility operators were incorporated into the
analysis as appropriate. Facility operators received information relating only to their own operation prior to
release of the Report.
ASSUMPTIONS
It should be noted that the following assumptions were made by R. W. Beck in preparing the results of
the cost analysis.
Facility Sorting Capacity and Material Composition
The composition of each facility's commingled plastic bottle feedstock and the rate at which each facility
could sort these materials were based on actual operating data provided by each facility for the three months
ending June 30, 1994. The information provided was adjusted for non-productive downtime due to lack of
feedstock and converted to pounds per operating hour for use in the analysis. In general, the composition of the
incoming baled commingled post-consumer plastic bottle feedstock was somewhat consistent from facility to
facility, although an adjustment was made to the first generation MSS system's trash/contaminants estimate (from
16.5 percent to 10.5 percent) for consistency with the other two facilities' estimates of 10.5 percent of gross
system inputs.
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Labor Rates. Residue Disposal Rates, and Building Lease Rates
Due to regional differences in costs which were considered to be external to the evaluation of the two
sorting technologies and may have interfered with the cost comparison, a decision was made to use standardized
labor rates, residue disposal rates, and building lease rates in the analysis. The analysis assumes mat labor rates
(including benefits) for sorting/inspection personnel were as Mows:
Line Sorters/Inspectors $7.00 per hour
Sort Line Supervisors $11.00 per hour
Debaler Operator $8.00 per hour
Sort Line Mechanics $10.00 per hour
Disposal rates were assumed to be $50 per ton plus an additional $100 fee per pull. Building lease rates
were assumed to be $3.00 per square foot per year. These standard values were based on input from the facility
operators as well as R. W. Beck project staff.
Operating Schedule
In general, the three facilities' operating schedules during the three month test period varied in terms of
the number of operating hours per shift and the number of shifts per week.
To allow for an unbiased side by side comparison of the facilities, it was necessary to use a standardized
operating schedule of two eight hour shifts per day, seven days a week for a total of 14 shifts per week. Material
throughput, labor usage, and applicable operating expenses were also adjusted as appropriate. Based on R. W.
Beck's previous experience with similar facilities, all three facilities were judged to be capable of operating on a
two shift per day basis with a third shift for maintenance and cleanup as required. It was felt that operating at
higher operating rates would likely reduce the estimated useful life of the equipment and potentially the quality of
the end product produced.
Equipment Capital Cost
Capital cost estimates for sorting equipment used by each of the facilities were based on the actual
capital cost incurred during sort line purchase, engineering, installation, and startup or on estimates for new
equipment if the installed equipment was purchased used.
Maintenance. Supply, and Utility Costs
Maintenance and supply cost estimates for each facility were based on actual historical cost data
provided by the facility operators when available as well as input from the R. W. Beck project staff based on
maintenance and supply costs for similar types of operations.
It should be noted that the second generation MSS system's parts and supplies costs provided for the
analysis were adjusted higher to compensate for the fact the facility is currently under warranty and me facility
operator will likely incur higher maintenance and repair costs over the remaining life of the system when the
warranty expires.
15
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Labor Requirements
Labor requirements for each facility's sort line were based on actual operating data for the three month
period ending June 30, 1994 as well as information collected by R. W. Beck staff during site-tests and
discussions with facility operators. The cost associated with laborers performing multiple tasks were allocated
based on the estimated percentage of time spent performing each task.
Sort Line Space Requirements
Building space requirements were based on facility operator estimates as well as site-visit estimates
prepared by R. W. Beck project staff. In general, each facility required approximately ten thousand square feet
of industrial type building space to house its respective sort line operation.
Equipment Life
The facilities typically depreciated their fixed equipment over 5 to 10 years. For purposes of this
analysis, the equipments' depreciable life was based on R. W. Beck's estimate of the equipment's useful life
assuming that care is taken to maintain the integrity of the equipment through normal scheduled maintenance and
repairs. The useful life of the equipment was also determined based on input from the facility operators and the
MSS equipment vendor.
Cost of Capital
The cost of capital to a facility is based primarily upon the borrower's ability to repay the loan amount
plus interest. Factors that affect the cost of capital can vary greatly with determinants such as company size,
tangible asset value, and cash flow being key considerations. Since this analysis is not intended to evaluate each
companies financial wherewithal, but rather the cost effectiveness of its sorting operation, the cost of capital for
this analysis has been standardized for all three facilities at 8 percent per year.
Adjustments for System Differences
Differences in operating practices, seasoning of sort operations staff, quality/purity of the sort being
performed, and length of operating history make comparison of the facilities on an "as is" basis less than ideal for
determining which system is more cost effective in practice. In an attempt to present as close to an "apples to
apples" comparison of the systems as possible, the cost comparison was prepared to take into account the
following system differences.
-Operating Practices—
As discussed in Section 3, to ensure the removal of PVC and any clustered or clumped bottles from the
commingled bottle stream, the PVC detection line at the second generation MSS facility was set at a very low
tolerance level which resulted in the ejection of approximately 4.8 percent of primarily PET and HOPE bottles on
the PVC line. These PET and HDPE bottles were not removed from the PVC stream, but rather sold with the
PVC in bale form. Alternatively, the first generation MSS facility and the manual sort facility sorted, for all
practical purposes, all PET and HDPE bottles into their respective homogeneous streams. For purposes of this
cost analysis, it was assumed that one half of one inspector's time per shift would be required on the PVC sorting
line if the second generation MSS facility were to sort these PET and HDPE bottles.
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-Quality/Purity of Sort Perfbrmed-
Several differences in the quality/purity of the sort were adjusted for in die cost comparison results.
First, PET at the manual sort facility is sorted into a single commingled stream of clear and green PET
bottles and sold in a baled form. Alternatively, bom of the MSS facilities sort PET into separate clear and green
streams to capture the higher value associated with the color sorted PET material. The first generation MSS
facility manually separates green and dear PET, while the second generation MSS facility uses separate ejection
lines for this purpose. Although the manual sort facility sorters currently handle each PET bottle, it is still
expected that some level of additional labor would be required if the sorters were required to separate the PET
into clear and green color streams. For purposes of the cost comparison, it was assumed that this additional PET
separation would require the addition of one half of one sorter's time per shift
Second, the manual sort facility, unlike the MSS facilities, attempted to remove all caps from HOPE
natural bottles to improve the purity of the output stream. It was assumed that this additional quality control
procedure added one half of one sorter's time per shift to the manual sort facility's operation. Labor requirements
for the manual sort facility were reduced by this amount in the cost analysis for comparison to the two MSS
facilities.
Third, the manual sort facility and the first generation MSS facility separated polypropylene (PP) bottles
from the commingled bottle stream, whereas these bottles were removed as trash by the second generation MSS
facility. However, it was assumed that separation of PP bottles for recovery at the second generation MSS
facility could be accomplished using existing labor, so adjustments to the labor requirements at the second
generation MSS facility for recovery of PP were not made.
Fourth, the manual sort facility baled PET whereas the MSS facilities granulated the PET soled at their
respective facilities. For the manual sort facility to upgrade the purity level of PET sorted at its facility to allow
for grinding of the PET material, it was assumed that one half of an additional laborer's time and PVC detection
equipment would be required. For purposes of the cost comparison, it was assumed mat the manual sort facility
would need to purchase an automated PVC detector at a cost of $100,000 with a useful life of seven years.
Operation and maintenance costs associated with the automated PVC detection equipment were assumed to be
$1,000 per year.
-Length of Operating History-
Unlike the other two facilities, the second generation MSS facility had only been in operation for
approximately nine months at the time of this analysis. Alternatively, the manual sort facility and the first
generation MSS facility had each been operating at least three years. As a result, it is likely that the second
generation MSS facility will improve its operating performance once operating personnel have had sufficient time
to learn to operate and maintain the system more effectively. It is anticipated that such improvements in operating
efficiency may result in a more optimal use of the inspection personnel on each of the sorting lines, as well as an
increase in the facility throughput per hour. For purposes of the cost comparison, it was assumed that labor
requirements would be reduced by one half of one inspector's time per shift to account for operational
improvements. The second generation MSS facility has targeted mis labor savings to oflset the anticipated labor
increase associated with the recovery of PET and HOPE on the PVC sorting line as discussed above.
17
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Not an Audit
In conducting the cost analysis, R. W. Beck relied on technical and cost information furnished by the
participating facility operators. Each facility supplied three months of historical operating and production data,
as well as capital costs and operations and maintenance costs for their equipment, as well as labor usage in terms
of staff-hours utilized for the sorting function. R. W. Beck did not independently verify the information provided
or examine each facility's books. We believe the information provided by the facility operators was reliable, but
cannot guarantee the accuracy of the information.
SURVEY LIMITATIONS AND OTHER CONSIDERATIONS
Persons using the results of this cost analysis should be aware of the following limitations and other
considerations.
Limited Study
Three facilities were evaluated. Other facilities perform the same functions evaluated in this survey,
using various processing methods. Although it is believed that these facilities represent a reasonable cross-section
of the industry, other operations may be more or less costly than those studied here.
One Operating Scenario
Costs for each facility were based on recent operating histories. Plastic sorting/recycling facilities
operate in a rapidly changing marketplace, and future costs can vary from the historical costs reported in this
evaluation for many reasons. The sort line operating productivity at the facilities can change based on changes in
technology, work force motivation and training, attention to equipment maintenance and repairs, seasonal
variations in feedstock composition, and other factors. Costs are likely to change over time with improvements.
All the participating facilities had made improvements in recent months and/or had plans for plant and operating
modifications in the near future.
New Systems
Many facilities use relatively new systems or new applications of older systems (i.e., MSS BottleSort*
system). Long-term operating experience, and thus long-term operating costs and equipment life-spans, are not
well defined at this time.
Changing Feedstocks
Introduction of new plastic containers can affect sorting costs. For example, widespread use of yellow
HOPE for 1-gallon milk jugs or the introduction of blue PET bottles could increase sorting costs at these
facilities.
Changing Regulations
Future regulatory changes could impact the cost of sorting operations. For example, if state regulations
were passed that required all plastic containers and/or packaging to be collected and recycled, the cost to process
this highly fractionalized mix of materials would likely be significantly higher than the costs reflected in this
report.
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COST COMPARISON RESULTS
Key input variables used in the cost analysis and the overall cost comparison results are shown in Tables
1 and 2, respectively. The cost comparison results are also depicted in Figure 4.
Table 1 lists the input variables used in performing the cost analysis, broken down between standardized
variables and hems that were allowed to vary from facility to facility for comparison purposes. As mentioned
previously, operating schedule, labor, disposal, and building lease rates were standardized to alleviate regional
cost differences.
Alternatively, sorting capacity per hour, as determined from three months of each firm's operating data,
equipment useful lire, and personnel, utility, maintenance/supplies, building space and capital requirements were
considered to be variable based upon the type of sorting technology in use. As a result, actual facility specific
data was used for these items.
As shown in Table 2, the results indicate that the second generation MSS facility has the most cost
effective commingled plastic bottle sorting operation with an overall cost of 3.7 cents per pound of material sorted
(excluding trash for disposal). The comparable figures for the first generation MSS facility and the manual sort
facility are 4.1 and 4.8 cents per pound, respectively. Based on these estimates, the second generation MSS
facility has a 0.4 cents per pound or 11 percent cost advantage over the first generation MSS facility and a 1.1
cents per pound or 24 percent cost advantage over the manual sort facility.
The figures clearly indicate that the need for additional sorting labor at the manual sorting operation is
the principal reason for its high cost relative to the two MSS facilities. As shown in Table 2, the manual sort
facility's labor requirement amounts to 4.0 cents per pound of material sorted as opposed to 2.3 cents per pound
for the first generation MSS facility and 2.2 cents per pound for the second generation MSS facility. Labor
requirements represent 83 percent of total costs for the manual sort facility, while labor requirements represent 56
and 61 percent at the first and second generation MSS facility', respectively. While the first and second generation
MSS facilities using the BottleSort* system are more capital intensive (requiring between 1.0 and 1.2 cents per
pound in amortized equipment cost, respectively, as compared to 0.4 cents per pound for the manual sort facility'),
the difference in capital costs is not enough to counter the substantial labor savings provided by the automated
sorting system.
The remaining operating costs (Parts & Supplies, Utilities, and Building Lease), although varying
slightly, are similar enough for all three facilities to be considered of little impact in determining the outcome of
the analysis. Clearly, the results indicate that the comparison is focused on the trade off between labor and
capital equipment.
Startup costs for the first generation MSS system were found to be somewhat higher than the second
generation system primarily due to higher installation and engineering costs. These higher startup costs were
mostly attributable to the prototype nature of the system.
It should be noted that other improvements have been identified which could potentially increase the cost
savings of the second generation MSS facility over the manual sort facility. Installation of a take-away conveyor
to remove trash from the sorting lines directly to a trash compactor would reduce the need for a laborer to
manually remove the trash from the sorting line. Additionally, extension of the first (PVC) sorting line to allow
for metering of the material ejected onto this Line would make it possible to staff mis line with a part time
inspector (as opposed to a full time inspector as assumed in the cost analysis). In total, these improvements might
reduce labor requirements at the second generation MSS facility' by as much as one full time laborer, thereby
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improving the cost advantage of this system over the manual sort facility by approximately an additional 5
percent
Table 1
COMPARISON OF KEY INPUT VARIABLES BY FACILITY
First Generation MSS
Facility
Second Generation MSS
Facility
Manual Sort
Facility
Standardized Inputs
Hours/Shift
Shifts/Week
Tip Fee/Ton ($Aon)
Fee/Pull
Building Lease/sq.ft./yr.
Cost of Capital
8
14
50
100
$3.00
8.0%
8
14
50
ioo
$3.00
8.0%
8
14
50
100
$3.00
8.0%
Labor Rates incl. benefits
($/Hour)
Sorters
Supervisors
Mechanics
$7.00
$11.00
$10.00
$7.00
$11.00
$10.00
$7.00
$11.00
$10.00
Variable Inputs
Sorting Capacity/Hour '
Capital Requirements2
Annual Maintenance &
Supply Costs
Building Space
Requirements
Annual Utilities ($/year)
2,400 Ibs
$156,539
$24,000
9,600 sq ft
$15,521
3,600 Ibs
$189,191
$45,000
9,000 sq ft
$11,160
3,000 Ibs
$59,907
$25,000
1 0,000 sq. ft
$15,274
Personnel per shift
Sorters/Inspectors
Supervisors
Bale Breaker/Operator
Mechanics
Equipment Useful Life
5.00
0.25
0.75
0.63
7 years
7.70
0.75
0.90
0.25
7 years
12.20
1.00
1.00
0.25
7 years
1 Based on three months of operating data, sorting capacity/hour includes actual downtime due to breaks
and equipment malfunctions for the three month period.
2 Capital requirements include annual amortization costs of fixed sorting equipment, including debalers,
conveyors, screens, PVC detectors, BottleSort* separation lines, and installation/setup.
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Table 2
COST COMPARISON OF FIRST AND SECOND MSS GENERATION FACILITIES
TO MANUAL SORT FACILITY
(Data Excludes Trash For Disposal)
Cost Category
Labor & benefits
Equipment
depreciation &
amortization
Parts & supplies
Utilities
Building Lease
Total
First Generation MSS
Facility
cents/lb
2.3
1.2
0.2
0.1
0.2
4.1
% of Total
56.4%
30.3%
4.7%
3.0%
5.6%
100%
Second Generation MSS
Facility
cents/lb
2.2
1.0
0.2
0.1
0.1
3.7
% of Total
60.6%
27.4%
6.5%
1.6%
3.9%
100%
Manual Sort
Facility
cents/lb
4.0
0.4
0.2
0.1
0.2
4.8
% Total
82.7%
8.0%
3.3%
2.0%
4.0%
100%
Note: Values may not add due to rounding.
Figure 4
COST COMPARISON RESULTS
o.o
1st Generation MSS
System Costs:
2nd Generation MSS
Manual Sort
D Labor &
Benefits
Equipment
Amortization
Parts*
Supplies
Utilities
Building
Lease
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FIXED AND VARIABLE OPERATING COSTS
Sorting costs were also divided into fixed and variable operating costs. Fixed operating costs included
amortization of fixed equipment and property lease costs. Variable operating costs included costs for personnel,
parts, supplies, and utilities associated with the sorting function. Table 3 summarizes the fixed and variable costs
for the three facilities.
As would be expected, fixed operating costs of the two MSS facilities were generally higher than that
reflected for the manual sort facility due to the increased amortized equipment cost associated with the MSS
BottleSort® equipment. As shown in Table 3, fixed costs of the first and second generation MSS facilities were
estimated to be 1.5 and 1.1 cents per pound, respectively. Fixed costs associated with the manual sort facility
were estimated to be only 0.6 cents per pound.
Variable operating costs, alternatively, were estimated to be significantly higher for the manual sort
operation, primarily as a result of the increased labor requirements for the facility. As shown in Table 3, the
manual sort facility's variable costs per pound were estimated to be 4.2 cents, of which 4.0 cents were associated
with labor costs. The first and second MSS facilities' variable costs per pound were estimated to be 2.6 and 2.5
cents, respectively, of which 2.3 and 2.2 cents, respectively, were labor related.
Table 3
ESTIMATED FIXED AND VARIABLE OPERATING COSTS
FOR SORTING COMMINGLED PLASTIC BOTTLES
(All values in cents per pound of material sorted excluding trash for disposal)
First Generation MSS
Facility
Second Generation MSS
Facility
Manual Sort
Facility
Fixed Operating Costs:
Amortization-Fixed Equip.
Building Lease
Total Fixed Operating Costs
1.2
0.2
1.5
1.0
0.1
1.1
0.4
0.2
0.6
Variable Operating Costs
Labor and Benefits
Parts and Supplies
Utilities
Total Variable Operating Costs
2.3
0.2
0.1
2.6
2.2
0.2
0.1
2.5
4.0
0.2
0.1
4.2
Note: Values above may not add due to rounding.
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SORTING COSTS BY RESIN TYPE
A cost analysis was also performed to estimate the cost to sort plastic bottles by resin type at each
facility. Capital and operating costs used in the cost analysis were based on those used to perform the
overall sort cost analysis described above. Table 4 summarizes the breakdown of capital and labor
requirements by resin type.
As shown in Table 4, the first step in die resin specific cost analysis was to determine which costs
were directly allocatable to specific resin categories sorted at each facility. Based on field test observations
made by R. W. Beck personnel and input from the individual facility operators, certain capital and labor
personnel were allocated directly to specific resin categories, as shown in Table 4. In particular, capital
costs associated with the secondary PVC separators used by each of the MSS facility's and die assumed
automated PVC detection equipment used by the manual sort facility were allocated directly to the clear
PET resin category. All other capital related costs at the three facilities were considered to be non-resin
specific in nature and, therefore, allocated to all resin categories based on total volume sorted.
Additionally, labor requirements were allocated in a similar fashion to each resin category, as
shown in Table 4. The labor requirements associated with sorters sorting multiple resins were allocated
based on the volume of each resin type processed by each sorter. Labor requirements considered non-resin
specific in nature (including supervision, bale breaking, and mechanical repair related labor) were allocated
to all resin categories based on total volume sorted. The actual allocation of costs to each resin category is
shown in Table 5.
The allocated resin specific costs generated for each facility were then used to estimate an average
cost per pound to sort by resin type. As shown in Table 6, the cost per pound to sort the various resin
categories was found to be somewhat higher at the manual sort facility. Of particular interest is the
relatively high cost to sort PVC and PP at the manual sort facility when compared to the two MSS
facilities. The results indicate that recovery of minority streams is performed more cost effectively when
automated separation is used. Yet, it should be noted that due to the relatively small quantities of PVC and
PP processed by each facility, estimation of the cost to process these two resin streams is difficult at best
without performing an extensive time and motion analysis to estimate the exact quantity of labor used by
each facility to recover PVC and PP. It should also be noted that the cost to process PVC specifically at
the second generation MSS facility is slightly understated due to the fact that a certain quantity of PET and
HDPE are ejected on the PVC line and are included in the calculation of the cost per pound to sort PVC.
The PET and HDPE ejected on the PVC line are sold in the PVC-rich product at a lower price than is
received for pure HDPE and PET products generated further down the processing line.
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Table 4
BREAKDOWN OF CAPITAL AND LABOR REQUIREMENTS
BY RESIN TYPE
1st Generation MSS
Facility
2nd Generation MSS
Facility
Manual Sort
Facility
Capital Costs Allocated to:
Natural HOPE
Colored HOPE
Clear PET1
Green PET
PVC
PP
Non-Resin Specific Capital Costs
Total Capital Costs
$0
$0
$75,000
$0
$0
$0
$740,000
$815,000
$0
$0
$100,000
$0
$0
$0
$885,000
$985,000
$0
$0
$100,000
$0
$0
$0
$211,900
$311,900
Labor Requirements Allocated to: (sorters/shift) — all sorting staff, not just sorters
Natural HOPE
Colored HOPE
Clear PET
Green PET
PVC
PP
Non-Resin Specific Labor
Total Labor Requirements
2.40
0.80
1.30
0.35
0.10
0.05
1.63
6.63
2.10
0.85
2.80
0.75
0.20
O.OO2
2.90
9.60
4.50
2.10
3.553
0.953
0.55
0.55
2.25
14.45
1 Capital costs associated with secondary PVC detection system used on clear PET line at first and second
generation MSS facilities and assumed automated PVC detection system at manual sort facility.
2 Resins were not sorted into the category shown.
3 Manual sort facility adjusted to reflect separation of clear and green PET per cost analysis.
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Tables
BREAKDOWN OF RESIN SPECIFIC ANNUAL AMORTIZED
CAPITAL AND OPERATING COSTS1
1st Generation MSS
Facility
2nd Generation MSS
Facility
Manual Sort
Facility
Amortized Capital Costs:
Clear PET Related2
Non-Resin Specific
Total Amortized Capital Costs
$14,405
$142,134
$156,539
$19,207
$169,984
$189,191
$19,207
$40,700
$59,907
Operating Costs:
Labor Related:
Natural HOPE Related
Mixed Color HOPE Related
Clear PET
Green PET
PVC
PP
Non-Resin Specific Labor
Total Labor Related Costs
Other Non-Resin Specific Costs
Total Amortized Capital and
Operating Costs
$97,843
$32,614
$52,998
$14,269
$4,077
$2,038
$87,360
$291,200
$68,321
$516,060
$85,613
$34,653
$114,150
$30,576
$8,154
$o4
$145,309
$418,454
$83,160
$690,806
$183,456
$85,613
$144,6483
$38,8083
$22,422
$22,422
$125,216
$622,586
$70,274
$752,766
Values may not add due to rounding.
2 Amortized capital costs associated with secondary PVC detection systems used on the clear PET line at
first and second generation MSS facilities and assumed automated PVC detection system at manual sort
facility.
3 Manual sort facility adjusted to reflect separation of clear and green PET per cost analysis.
Resins were not sorted into the category shown.
25
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Table 6
SORTING COST BY RESIN TYPE1
(in cents per pound)
1st Generation MSS
Facility
2nd Generation MSS
Facility
Manual Sort
Facility
Resin Specific Sorting Costs2
Natural HOPE
1.9
1.3
2.7
Colored HOPE
1.2
1.3
3.1
Clear PET
1.9
2.1
3.9'
Green PET
2.4
1.5
3.73
PVC
1.6
0.7
6.4
PP
1.3
0.0*
6.1
Non-Resin Specific Sorting Costs5
2.4
2.1
1.5
Total Resin Sorting Costs
Natural HOPE
4.2
3.4
4.2
Colored HOPE
3.5
3.4
4.6
Clear PET
4.3
4.3
5.43
Green PET
4.8
3.7
5.23
PVC6
4.0
2.8
7.9
1 Values may not add due to rounding.
2 Amortized capital and labor costs directly allocatable to the resin category shown.
3 Manual sort facility adjusted to reflect separation of clear and green PET per cost analysis.
4 Resins were not sorted into the categories shown.
5 All other sorting costs that were not directly allocatable to a resin category.
6 Second generation MSS facility PVC output included certain quantities of PET and HOPE (to ensure the
quality of the PET shown) which necessarily lowers the average cost per pound to process PVC.
26
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COST ANALYSIS FINDINGS
The results of the cost analysis generated the following findings.
• The first and second generation MSS facilities were found to be more cost effective than the
traditional manual sort system analyzed. The cost comparison results indicate that me first
generation MSS facility has a 0.7 cents per pound or 15 percent cost advantage over the manual
sort facility while the more sophisticated second generation MSS facility has a 1.1 cents per
pound or 24 percent cost advantage.
• The increased amortized equipment and maintenance and repair costs experienced by the
MSS facility operators were more than offset by the labor cost savings resulting from the
use of the MSS BottleSort® system.
• Despite the labor cost savings resulting from the use of the MSS BottleSort® system, labor
requirements continue to be a significant budget item at the MSS facilities. Based on the
results of the analysis, labor costs represented 56 percent and 61 percent of overall annual
sorting costs for the first and second generation MSS facilities versus the 83 percent
estimated for the manual sort operations.
27
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SECTION 5
FIELD TEST ANALYSES
OVERVIEW
The objective of the facility testing was two-fold: (1) to obtain comparative data for use in supplementing
an economic evaluation of the MSS BottleSort® systems versus a manual bottle sorting system, and (2) to obtain
information on the accuracy of the MSS BottleSort® systems.
Individual test plans varied in the number and duration of each test performed, based upon the operating
method at each facility, and the types of data which were obtainable and would allow for reasonable comparisons
among the facilities. Data were sought from the following categories:
• Data obtained from all three facilities representing "normal operations";
• "Machine accuracy" data obtained from the first and second generation MSS facilities to
estimate the quality of the sort performed by the MSS BottleSort® equipment only, excluding
labor; and
• Overall "system sort quality" data obtained from all three of the facilities to estimate the quality
of the sort including both equipment and labor.
The same basic test apparatus was required for the testing at all three facilities. Test apparatus included:
(1) a platform scale capable of weighing bales of commingled plastic containers and gaylords filled with flake or
whole bottles, (2) a forklift and forklift operator for moving bales, gaylords, and other containers, (3) operations
personnel to assist in sorting of gaylords of "mistake" bottles according to resin types and color, and (4) R. W.
Beck personnel supplied with watches and logbooks, to observe operations, direct mistake sorting, and record test
results.
The following is a brief summary of the methodologies utilized for the field testing.
NORMAL OPERATIONS TESTS
Many factors can affect day-to-day sorting operations. One goal of this study was to provide data that
reflected long-term average operations, not just one test shift which may be particularly "bad" or particularly
"good." Therefore, the normal operations tests at each facility were intended to supplement and highlight the
three months of operating data provided by each facility and summarized in Section 4.
Two key factors that affect day-to-day normal operations at these facilities are interrelated: the quality
of the baled, commingled containers, and the hourly throughput of the sorting line. The quality of bales varies
with (1) the level of contamination with film plastic and other non-bottle materials, (2) the composition of the
incoming bales (the type and number of bottles in the bale), (3) the level of compaction in the bales, and (4)
whether the containers were recovered from mixed waste or from source-separated materials. Therefore, it was
decided that commingled bales from a common source would be used during the normal operations test at all
three facilities. As a result, approximately 35,000 pounds of material collected and baled by one community was
provided for processing by each test facility during the normal operations test. The material was selected by the
three facility operators as representative of their "typical" average feedstock streams.
28
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Besides being affected by the quality issues mentioned above, the throughput of the systems are also
affected by the feed conveyor speed, how rapidly jams or machine faults are corrected, and die aggressiveness of
the personnel performing manual separation at each of the facilities.
Therefore, the purpose of the normal operations test was to (1) verify the reasonableness and provide
context for data which is routinely measured by the facility, (2) obtain data which is not routinely measured by
the facilities, such as individual input bale weights and/or individual product gaylord weights, and (3) allow for
close observation of the benefits and limitations of each facility's system.
System Definitions
The normal operations tests take into consideration the entire sorting system used at each facility,
including bom equipment and operators. In the facilities utilizing BottleSort* equipment, the automated
equipment provides an important separation function with its automated detection and ejection points. However,
the equipment alone does not provide the quality of separation desired Manual inspectors are needed to perform
additional separations, check lor quality, feed materials, and dear faults.
The components of the systems evaluated consisted of system inputs, outputs, labor requirements, and
various physical equipment System inputs included baled commingled containers. System outputs included
sorted products, byproducts (such as used baling wire) and residues (such as unders from the disc screens and
film plastics). For the two MSS facilities, physical equipment included debating and declumping equipment,
conveyors, manual sorting stations and BottleSort* system components. For the manual sort facility, the physical
equipment included the debaler, conveyors, bale table, disc screen and elevated sorting lines. Granulation and/or
baling systems were not considered to be part of the systems. However, since in most instances the sorted
product Lines were further processed immediately after sorting, baled or granulated material was used to estimate
the quantity of product sorted. Labor was based on the actual number of system operators required to operate
each system during normal operations.
Test Parameters
The normal operations tests were performed over a time period approximately equivalent to a single
normal operating sort shift Operations staffing utilized the usual complement of operators. Operations personnel
proceeded with their regular routines, including routine record keeping operations, breaks, and responses to
problems such as blocked conveyors. The only change from "normal operations" was (1) weighing each bale of
incoming commingled containers prior to their reaching the system, (2) weighing any product (bales or gaylords
containing ground material) which would not otherwise be recorded, and (3) weighing all residues and trash prior
to disposal.
During the test period, R. W. Beck staff gathered information on (1) input product types and weights, (2)
output product types and weights, (3) the timing of various events, (such as BottleSort9 system start and stop
times), and (4) unscheduled downtime. Additional operational observations, such as shift changes and conveyor
speed changes and setpoints were also recorded.
At the end of the test periods, any partially filled containers were weighed and logged, and the weight of
any partially-fed bale on the feed platform was visually estimated by experienced facility employees (bale breaker
operators).
29
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Test Results
Tables 7 through 9 summarize the raw data gathered during the normal operations tests at the first
generation MSS facility, the second generation MSS facility, and the manual sort facility, respectively.
Table?
FIRST GENERATION MSS FACILITY
NORMAL OPERATIONS TEST SUMMARY
Input/Output
Total Inputs to System
Net Weight (Lbs)
31,341
% Input
100%
Outputs from System
Clear PET Bottles
Green PET Bottles
Dairy "A" (Clean Natural HOPE Bottles)
Dairy "B" (Other Natural HOPE Bottles)
Mixed Color HDPE Bottles
PVC/Other Bottles/Trash
Bale Wire
Total Outputs from System
Difference from Inputs
Category
Gross Normal Operations Test Time
7,139
1,304
8,138
5,148
4,320
4,206
147
30,402
939
Time
8 Hours 50 Minutes
23%
4%
26%
16%
14%
13%
<1%
97%
3%
% of Total
100%
Less Down Time Due to:
Equipment Malfunction
Breaks
Total Down Time
Net Operating Test Time
40 Minutes
1 Hour 23 Minutes
2 Hours 3 Minutes
6 Hours 47 Minutes
7%
16%
23%
77%
Input Pounds Sorted Per Hour:
Based on Gross Operating Time
Based on Net Operating Time
3,548 Lbs/Hour
4,620 Lbs/Hour
30
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Tables
SECOND GENERATION MSS FACILITY
NORMAL OPERATIONS TEST SUMMARY
Input/Output
Total Inputs to System
Net Weight (U*)
31,941
% Input
100%
Outputs from System
Clear PET Bottles
Green PET Bottles
Natural HOPE Bottles
Mixed Color HOPE Bottles
PVC/Other Bottles/Trash
Bale Wire
Total Outputs from System
Difference from Inputs
Category
Gross Normal Operations Test Time
8,127
1,940
11,841
4,878
4,689
129
31,604
337
Time
8 Hours 2 Minutes
25%
6%
37%
15%
15%
<1%
99%
1%
% of Total
100%
Less Down Time Due to:
Equipment Malfunction
Breaks
Total Down Time
Net Operating Test Time
Input Pounds Sorted Per Hour
Based on Gross Operating Time
Based on Net Operating Time
21 Minutes
1 Hour 4 Minutes
1 Hour 25 Minutes
6 Hours 37 Minutes
3,976 Lbs/Hour
4,827 Lbs/Hour
4%
13%
17%
83%
31
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Table 9
MANUAL SORT FACILITY
NORMAL OPERATIONS TEST SUMMARY
Input/Output
Total Inputs to System
Net Weight (Lbs)
29,035
% Input
100%
Outputs from System
Clear and Green PET Bottles
Natural HOPE Bottles
Mixed Color HOPE Bottles
PVC/Other Bottles/Trash
Bale Wire
Total Outputs from System
Difference from Inputs
Category
Gross Normal Operations Test Time
Less Down Time Due to:
Equipment Malfunction
Breaks
Total Down Time
Net Operating Test Time
Input Pounds Sorted Per Hour
Based on Gross Operating Time
Based on Net Operating Time
8,270
9,443
3,800
2,885
114
24,512
4,523
Time
8 Hours 1 5 Minutes
0 Minutes
50 Minutes
50 Minutes
7 Hours 25 Minutes
3,519 Lbs/Hour
3,915Lbs/Hour
28%
33%
13%
10%
<1%
84%
16%
% of Total
100%
0%
10%
10%
90%
It should be noted that the line titled "Difference from Inputs" in Tables 7 through 9 represents the
amount of input material which was not accounted for in the weights recorded for all the output material. This
difference is significant for the normal operations test conducted at the manual sort facility. The main cause of
this difference was visual estimation of the weight of bottles sorted during the test which were not processed
(baled or granulated) and, as a result, not physically weighed during the test It should also be noted that a shift
changeover occurred at the first generation MSS facility during the normal operations test. Adjusting for this
feet, down time due to breaks would have actually been 10 percent (versus 16 percent), while overall down time
would have been only 18 percent (compared with 23 percent as shown in Table 7).
32
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The residues found during the normal operations test at all the facilities consisted mainly of caps,
lids, and labels. During die testing, the bottles coming out of the debating equipment appeared to be in
relatively good condition; that is, the bottles were mostly whole and separated. Overall, based on
discussion with each facility manager, the quality of the bales used during the normal operations test at all
three facilities represented material which was very representative of commingled bales normally sorted by
these facilities.
Test Comparison
The main objectives of the normal operations test were to verify the reasonableness and to provide
context far the three months of historical operating data to be provided by each fecility. Table 10 summarizes the
throughput in terms of pounds of resin sorted per hour at each ^ility during the nonnal operations test as vvell as
similar qiiantities detemuiied fhxn three The values
shown in Table 10 for the normal operations tests ("Normal Ops") are shown in pounds sorted per hour for
comparison with the three months of historical operating data.
Total amounts sorted were actually higher during the normal operations tests than the historical
three month period. Please note that the normal operations tests were one time events conducted during
only one operating shift per facility, and therefore can vary greatly when compared to the average of three
months of data.
As shown in Table 10, it was determined that during the normal operations tests, the average
processing capacity for the BottleSort* first and second generation MSS systems was 3,548 and 3,976
pounds per hour, respectively. However, by netting out the amount of time during the tests that the
BottleSort* equipment was not actually operating (for breaks and equipment malfunction), the NET
average speed for the BottleSort" system at the two facilities increases to 4,620 and 4,827 pounds per hour,
respectively (see calculation in Tables 7 and 8, respectively). The nameplate line capacity for both
facilities is 5,000 pounds per hour, suggesting that during the normal operations tests, the BottleSort*
system was running at near its nameplate tine capacity.
33
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Table 10
COMPARISON OF HISTORICAL OPERATING DATA
TO NORMAL OPERATIONS TEST
(Pounds Sorted Per Hour)1
MbedOear
+GreenPET
Clear PET
Green PET
Natural
HOPE
Mixed Color
HOPE
PVC
PP
Trash/
Other
Difference4
Total
First Generation MSS
Facility
Normal
Ops
See Note 2
808
148
1,504
501
14
11
456
106
3,548
3 Mo*.
Data
See Note 2
605
102
902
476
43
28
411
2,567
Diff.
+34%
+45%
+67%
+5%
-67%
-61%
+11%
+38%
Second Generation MSS
Facility
Normal
Op.
See Note 2
1,012
241
1,474
607
296 3
See Note 2
304
42
3,976
3 Mo*.
Data
See Note 2
1,067
339
1,161
464
206 3
See Note 2
381
3,618
Diff.
-5%
-29%
+27%
+31%
+44%
-20%
+10%
Manual Sort
Facility
Normal
Ops
1,002
See Note 2
SeeNote2
1,145
461
30
30
303
548
3,519
3 Mo*.
Data
900
SeeNote2
See Note 2
1,185
477
60
63
315
3,000
Diff.
+11%
-3%
-3%
-50%
-52%
-4%
+17%
1 For comparison purposes, the data shown is based on a pounds sorted per hour basis including downtime
due to breaks and equipment malfunction.
2 Bottles were not sorted into these categories for the facilities shown.
3 For the second generation MSS facility, the material stream being characterized as "PVC" actually
contained certain amounts of other resin types, including PET and HOPE.
4 Represents the difference in the amount of input material and the sum of all the output material.
During the normal operations test at the second generation MSS facility, there were three instances
where bales on the infeed conveyor turned sideways, causing delays in the processing of those bales. Based
on our observations, each occurrence causes approximately a 10 minute delay. The facility manager
explained that this was a fairly common occurrence, and that this problem occurred when other bales were
not kept in back of the bale which was currently being fed to the debater. This problem was not
experienced by the operators of the first generation MSS facility, which has the same debating equipment.
Therefore, it is suggested that MSS review the operation of such equipment at the second generation MSS
facility to determine the cause of the problem. The normal operations test data shows that productive
operating time could be increased by approximately 5 percent if this problem was alleviated.
34
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ITEM COUNT MACHINE ACCURACY TEST
The objective of the item count machine accuracy test was to measure and compare the efficiency of the
first and second generation MSS BottleSort® systems in identifying and separating post-consumer plastic bottles
by resin type and color without benefit of human intervention to correct for ejection mistakes. This test
represented a significant change from routine operations in that the BottleSort® equipment was allowed to operate
without human intervention.
System Definitions
The components of the systems that were evaluated as part of the item count machine accuracy test
consisted of physical equipment, inputs, and outputs. Physical equipment included only the BottleSort® system
components. System inputs consisted of baled, commingled plastic bottles. System outputs consisted of correctly
and incorrectly ejected plastic bottles.
Test Parameters
The test duration for each facility was approximately ten minutes. Prior to the test period, commingled
baled materials typical of those normally processed at each facility were selected. During the test period,
operations personnel proceeded with normal operations, including routine record keeping operations and
responses to problems, such as blocked conveyors. However, no manual sorting was performed during this test.
Rather, sorting personnel were requested to remove all materials ejected at each line and place them into separate
empty gay lords.
After the test period was completed, the collected bottles were categorized into either correctly or
incorrectly ejected bottle categories, and counted. Additionally, a visual characterization of the resin type of the
incorrect bottles was conducted. Bottles coded #5 and #7 with opacity similar to natural HOPE were considered
correct when ejected at the fourth ejection point. Similarly, opaque containers coded other than #2 found on the
last sorting line were considered correct ejections. It should be noted that the sensitivity of the primary PVC
detection unit (Ejection Point No. 1) at the second generation MSS facility was set to a very high level, thus
ejecting approximately 4.8 percent of materials input to the system other than PVC, primarily HOPE and PET
bottles and some metal. Therefore, it was decided that no analysis of this ejection point would be performed.
Test Results
Tables 11 and 12 summarize the raw data gathered during the Item Count Machine Accuracy Tests at
the first and second generation MSS facilities, respectively.
35
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Table 11
FIRST GENERATION MSS FACILITY
ITEM COUNT MACHINE ACCURACY TEST SUMMARY
(values shown are in number of bottles counted)
Material Line
No. 1 - Clear & Green PET / PVC
No. 2 - Natural HOPE 1
End of Line - Mixed Color HOPE 2
Total
Total
Number
of Ejections
1,379
3,468
2,301
7,148
Correct Ejections
Number
1,038
3,120
671
4,829
%of
Total
75%
90%
29%
68%
Mistake Ejections
Number
341
348
1,630
2,319
%of
Total
25%
10%
71%
32%
Bottles coded #5 and #7 with opacity similar to natural HOPE were also considered correct ejections. Due to
time constraints, only two of the five gaylords produced on this line during the test were sorted. The number of
remaining unsorted bottles was estimated, and allocated as correct and mistake ejections based on the
percentages calculated for the sorted containers.
Opaque bottles coded other than #2 were also considered correct ejections. Due to time constraints, only two
of the three gaylords produced on this line during the test were sorted. The number of remaining unsorted
bottles was estimated, and allocated as correct and mistake ejections based on the percentages calculated for
the sorted containers. Other analyses have indicated that up to 70 percent of the "mistake" ejections on this line
are bottles such as PET smashed into base cups, PET twisted into "sticks", or dirty natural HOPE bottles. MSS
considers this a correct sort in that is assures the purity of the clear and colored PET and natural HOPE bottles.
36
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Table 12
SECOND GENERATION MSS FACILITY
IHM COUNT MACHINE ACCURACY TEST SUMMARY'
(values shown are in number of botdes counted)
Ejection Point
No. 2 - Clear PET Line
No. 3 - Green PET Line
No. 4 -Natural HOPE Line2
End of Line - Mixed Color HOPE 3
Total
Total
Number
of Ejections
2,318
439
1,798
868
5,423
Correct Ejections
Number
2,143
294
1,574
483
4,494
%of
Total
92%
67%
88%
56%
83%
Mistake Ejections
Number
175
145
224
385
929
%of
Total
8%
33%
12%
44%
17%
Ejection Point No. 1 (PVQ was not analyzed due to the high sensitivity setting used by this facility which
resulted in the ejection of a certain quantity of PET and HOPE on this line. Non PVC ejections (primarily
consisting of PET and HOPE bottles and small quantities of metal) on the PVC line were estimated to be 4.8
percent of the material input to the system.
2 Bottles coded #5 and #7 with opacity similar to natural HOPE were also considered correct ejections.
3 Opaque bottles coded other than #2 were also considered correct ejections.
Test Comparison
The objective of this test was to measure and compare the efficiency of the first and second generation
MSS BottleSort* systems in identifying and separating post-consumer plastic bottles by resin type and color
without benefit of human intervention to correct for sorting mistakes. Table 13 compares the item count machine
accuracy tests conducted at bom the first and second generation MSS facilities in terms of percentage of correct
ejections to the total number of ejections at each ejection point.
During the item count machine accuracy test at the first and second generation MSS facilities, the overall
rate of correct ejections for the entire BottleSort* system was 68 percent and 83 percent, respectively. While it
would appear that the second generation BottleSort* system provided a significant improvement in sorting ability,
it is important to note that the entire remaining material stream, including PET and natural HOPE bottles which
were not ejected at their appropriate ejection points, is diverted out of the system at the third detection point at the
first generation MSS BottleSort* facility. If instead, the third ejection point was to eject mixed color HOPE (as
designed), the accuracy rate of 29 percent for mixed color HDPE would likely have been higher. "Mistake"
ejections included PET smashed into base cups, PET twisted into "sticks", and dirty natural HDPE bottles, all of
which MSS considers correct sorts required to maintain product quality. These "mistakes" however, do still
represent a technical sorting limitation of the system.
37
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Table 13
COMPARISON OF ITEM COUNT MACHINE ACCURACY TESTS
(Correct Bottle Ejection Percentages Per Line)
Material
Clear PET
Green PET
Clear and Green PET
Natural HOPE
Mixed Color HOPE
Overall System
First Generation MSS
Facility
Total
Ejections
1,379
3,468 3
2,301 3
7,148
Correct
Ejections
1,038'
3,1 20 3
671 3
4,829
%
Correct
75%
90%
29%
68%
Second Generation MSS
Facility
Total
Ejections
2,318
439
2,757 2
1,798
868
5,423
Correct
Ejections
2,143
294
2,43 7 2
1,574
483
4,494
%
Correct
92%
67%
88%
88%
56%
83%
Difference
••-17%
-3%
+91%
+23%
In addition to clear and green PET, PVC is also correctly ejected at this station, and thus has been
included in the figure shown.
2 These figures represent the sum of clear and green PET.
3 Quantities as determined in Table 11.
The above comparison illustrates that changes made to the BottleSort* system from the first to the
second generation MSS facilities may have resulted in improvements in the system's ability to distinguish between
various plastic resins/colors. However, it should be noted that this comparison is as a result of only one ten-
minute test conducted at each facility. A more rigorous test plan would be required to conclude with certainty
that the second generation MSS BottleSort* system is more accurate than the system used at the first generation
MSS fecilfty.
BOTTLE WEIGHT MACHINE ACCURACY TEST
Tne objective of this test was to measure the efficiency of the second generation MSS BottleSort* system
in identifying and separating post-consumer plastic bottles by resin type and color without benefit of human
intervention to correct for sorting mistakes. This test differed from the Item Count Machine Accuracy Test in
that it fully characterized the bottles (by resin type) being incorrectly ejected at each ejection point. Operational
and space limitations did not allow for this test to be conducted at the first generation MSS facility. TTiis test
represented a significant change from routine operations, in that sorters deposited mistake and trash materials
(recovered from the belts downstream of the BottleSort* system) into gaylords instead of returning those
materials to their correct sort line.
38
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System Definition
The components of the system evaluated consisted of physical equipment, inputs, and outputs. Physical
equipment included only the BottleSort® system components. System inputs included baled, commingled plastic
bottles. System outputs included correctly and incorrectly ejected plastic bottles and residues.
Test Parameters
The test duration was approximately one and one-half hours and took place between about 7:30 a.m. and
9:00 a.m. The MSS BottleSort conveyor speed was set at 5.0 which represented throughput equivalent to nearly
5,000 pounds per hour. Prior to the start of the test period, two empty containers were placed by each of the
sorting personnel. Sorting staff were instructed to throw all bottles that were incorrectly ejected onto their
respective sorting lines into one of their two empty containers. The other container was used for trash (such as
lids, cups and film) removed from their respective sorting line. Additionally, one or more empty gaylords were
placed nearby each sorting line to accumulate all of the material from these lines.
Facility personnel proceeded with normal operations, including routine record keeping operations and
responses to problems, such as blocked conveyors. Filled mistake and trash containers were replaced with empty
containers as needed by R. W. Beck staff.
During the test period, R. W. Beck staff gathered information on input product types and weights, output
product types and weights, the timing of various events, such as BottleSort® system start and stop times, and
unscheduled downtime. Additional operational observations, such as the origin/sorting line of each filled gaylord,
BottleSort® system fault indications, and conveyor speed changes and setpoints were also recorded.
R. W. Beck staff directed and participated in sorting and weighing each mistake gaylord. The contents
of each gaylord were sorted into the following categories:
Clear PET bottles
Green PET bottles
Amber PET bottles
Blue PET bottles
Natural HOPE bottles
Blue tinted natural HOPE bottles
Colored HOPE bottles
HOPE injection molded containers
PVC bottles
LDPE containers
PP bottles
PS containers
Trash which was not discarded by sorting personnel during the test
The contents of each sorted gaylord were then weighed and recorded. Additionally, each gaylord
containing trash removed by the sorting personnel during the test period was weighed.
Test Results
Table 14 summarizes the raw data gathered during the bottle weight machine accuracy test conducted at
the second generation MSS facility.
39
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SYSTEM SORT QUALITY TESTING
The system sort quality test was used to determine how effectively different resins and colors are sorted
by each facility. The test was also performed to measure and compare the overall quality of plastic material
output produced by each facility.
System Definition
The components of the systems evaluated consisted of inputs, outputs, and various physical equipment
System inputs included baled commingled plastic bottles. System outputs included sorted products, byproducts
(such as used baling wire) and residues (such as unders from the disc screens and trash sorted along the line(s)).
For the two BottJeSort* facilities, physical equipment included debating and declumping equipment, conveyors,
manual sorting stations and BottleSort* system components. For the manual sorting facility, the physical
equipment included the debaler, conveyors, bale table, disc screen and elevated sorting lines.
Test Parameters
During each system sort quality test, facility operations proceeded normally (with the exception of the
second generation MSS facility, as discussed below). The test was performed lor two test periods at each
product line at each facility (other than the second generation MSS facility). During each test period, R. W. Beck
staff tallied the number of incorrect containers after all normal sorting had taken place (automated and/or
manual). Additionally, ground or baled material produced (on the line analyzed) during each test period was
weighed.
Test Results
Tables 15 through 17 summarize the raw data collected during the system sort quality test conducted at
tile first generation MSS facility, the second generation MSS facility, and the manual sort facility, respectively.
Test Comparison
The system sort quality test was used to determine how effectively different resins and colors are
separated by each facility and to measure and compare the overall quality of plastic material produced by one
facility with the product quality produced by the other two facilities. Based on the available markets for the
material they produce, a company may allow for different levels of contaminants in their product.
Table 18 summarizes the overall quality of the plastic materials (bales and flake) produced at the three
facilities. For those resins or color types that were tested twice (the tests at the manual sorting facility and the
first generation MSS facility), the overall quality is based on the weighted average of the two tests.
With the exception of the mixed color HDPE material produced at the first generation MSS facility, all
products generated at the facilities exceeded a 99 percent purity level. The mixed color HDPE material produced
at the first generation MSS facility does meet market specifications, however.
41
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Table 15
FIRST GENERATION MSS BOTTLESORT* FACILITY
SYSTEM SORT QUALITY TEST SUMMARY
Test/Material Tested
Contamination NOT
Removed by Inspectors
(Number of Containers)
Product Produced
During Test (pounds)
Test No. 1
Clear PET '
Green PET 1
Dairy A (Clean Natural HOPE)
Dairy B (Other Natural HOPE)
Mixed Color HOPE
Overall
1
2
16
5
49
73
123
41
95
66
106
431
Test No. 2
Clear PET 1
Green PET 1
Dairy A (Clean Natural HOPE)
Dairy B (Other Natural HOPE)
Mixed Color HOPE
Overall
2
0
3
6
23
34
143
37
139
197
124
640
None of the 5 mistakes on the PET line during the test were PVC bottles.
42
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Table 16
SECOND GENERATION MSS BOTTLESORT* FACILITY
SYSTEM SORT QUALITY TEST SUMMARY
Test/Material Tested
Contamination NOT
Removed by Inspecton
(Number of Containers)
Product Produced
During Test (pounds)
Test No. 1
Clear PET 1
Green PET
Natural HOPE
Mixed Color HOPE
Overall
3
0
3
See Note 2
6
227
41
544
See Note 2
812
Test No. 2 - See Note 2
1 None of the three mistakes on the clear PET line during the test were PVC bottles.
2 Because the primary system PVC detector malfunctioned during testing, a complete set of system
sort quality tests could not be completed for the second generation MSS BottleSort* facility.
Table 17
MANUAL SORTING FACILITY
SYSTEM SORT QUALITY TEST SUMMARY
Test/Material Tested
Contamination NOT
Removed by Hand Sorters
(Number of Containers)
Product Produced
During Test (pounds)
Test No. 1
Clear and Green PET
Natural HOPE
Mixed Color HOPE
PP (bales from Canada)
Overall
31
10
7
6
26
815
768
903
553
3,039
Test No. 2
Clear and Green PET
Natural HOPE
Mixed Color HOPE
PP (bales from Canada)
Overall
61
9
4
15
34
810
901
848
558
3,117
1 Four of the nine mistakes identified during the test were PVC bottles.
43
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Table 18
COMPARISON OF OVERALL PRODUCT QUALITY
(Based on ppm PVC ' in PET)
Material Line
# of Total
Mistakes/PVC
Mistakes
Weight of
Product (Lbs.)
# of Bottles
in Product 2
Mistake %
Parts Per
Million of
PVC1
First Generation MSS Facility
Clear PET
Green PET
Clear and Green PET
Natural HOPE
Mixed Color HOPE
pp3
Overall
3/0
2/0
30
72
107
266
78
497
230
1,071
2,128
750
3,288
1,285
7,786
0.1%
0.3%
0.9%
5.6%
1.4%
0
0
Second Generation MSS Facility
Clear PET
Green PET
Clear and Green PET
Natural HOPE
Mixed Color HOPE5
PP
Overall
3/0
0/0
3
~
6
227
41
544
~
812
1,816
394
3,599
—
5,809
0.2% 4
0.0%
0.1%
—
0.1%
0
0
Manual Sorting Facility
Clear PET
Green PET
Clear and Green PET
Natural HOPE
Mixed Color HOPE
PP
Overall
9/4
19
11
21
60
1,625
1,671
1,751
1,111
6,158
13,320
11,066
9,782
8,888
43,056
0.1%
0.2%
0.1%
0.5%
0.1%
300
See Notes on following page.
44
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Notes for Table 18:
1 Overall product quality as based on PVC contamination of PET in parts per million (ppm). Values above 100
ppm are not acceptable for end-use without additional automated PVC inspection. A value of 100 ppm
equates to less than one PVC bottle per gaylord of ground PET.
2 Weight of product in pounds converted to number of bottles based on average conversion factors developed as
part of machine accuracy test Number of bottles per pound: Clear PET - 8.00, green PET - 9.61, natural HOPE
- 6.62, mixed color HOPE - 5.59, clear/green PET - 8.20, PP - 8.00.
3 While this facility does produce PP flake, during the testing period, no PP flake was produced. Therefore, a
system sort quality test for PP could not be conducted.
4 Overall percentage is higher; this test was conducted prior to secondary PVC detector.
5 MSS BottleSort* system shut down early due to primary PVC detector failure; thus completion of this test did not
occur. This fault occurred after tests on the three ejection points listed were completed.
Field Test Results
It is critical to note that at the manual sort facility, four of the nine "mistakes" that were not identified by
the PET inspector were PVC bottles, which would be unacceptable to a potential buyer planning on using the
material without further sorting. As a result, PET product produced by the manual sort facility still requires
additional automated PVC detection by die customer purchasing this product material.
Alternatively, no PVC bottles were identified in the PET produced at the automated sort facilities.
Interestingly, at the second generation MSS facility, inspection of the material produced on the clear PET line
was conducted even before automated secondary PVC detection. The quality of PET produced at both MSS
facilities requires no further PVC detection by the end user and, as a result, has a much higher market value. The
cost comparison in Section 4 reflects the additional capital and operating costs that would be required if the
manual sort facility were to upgrade it's PET to an end user ready "PVC free" stream (typically less than 50 to
100 parts per million PVC) similar to the PET stream produced by either of the MSS facilities.
GOVERNMENT PRINTING OFFICE: WM - S5»4«1/MIM
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