A
PB-208 674
Evaluation, Extraction,
and Recycling of Certain
Solid Waste Components
Great Lakes Research Institute
1972
Distributed By:
National Technical Information Service
U. S. DEPARTMENT OF COMMERCE
5285 Port Royal Road, Springfield Va. 22151
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EPA-SW-35D-72
PB 208 674
EVALUATION, EXTRACTION, AND RECYCLING
OF CERTAIN SOLID WASTE COMPONENTS
This final report (SW~35d) on work performed under
solid waste management demonstration grant no. EC-00292
to Erie County, Pennsylvania,, was written by the
GREAT LAKES RESEARCH INSTITUTE
and is reproduced as received from the grantee.
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BIBLIOGRAPHIC DATA
SHEET
1. Report No.
EPA-SW-350-72
3. Recipient's Accession No.
4. Title and Subtitle
Evaluation, Extraction, and Recycling of Certain Solid
Waste Components
5- Report Date
1972
6.
7. Author(s)
Great Lakes Research Institute
8. Performing Organization Kept.
No.
9. Performing Organization Name and Address
Great Lakes Research Institute
155 West Eighth Street
Erie, Pennsylvania 16501
10. Project/Task/Work Unit No.
/Grant No.
Demonstration Grant No.
1-G06-EC-00292-01
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
Office of Solid Waste Management Programs
Rockville, Maryland 20852
13. Type of Report & Period
Stw3yveand Investigation
6/1/70 - 5/31/71
14.
15. Supplementary Notes
16. Abstracts
The constituents of municipal solid waste are identified along with relative weight
percentages typically found. Recycling priorities are established with respect to
realistic criteria. Though the study was performed for Erie,vP**, concepts may be
applied elsewhere. Paper, ferrous metals, aluminum, and rubber tires are listed, in
that order, with respect to desirability of extraction. Tin cans, glass, and plastics
are listed next under additional criteria. A survey of current technology is presentei
that briefly discusses unit processes as well as complete systems under development.
Many unit processes are found to be an outgrowth from mining practices. A device
called the "JJowerman Classifier" is presented and incorporated into a system with
potential to separate preprocessed municipal waste. The device operates on the
principle of Stoke's Law applied to a moving fluid. All else being held equal,
settling velocity will be proportional to density and thus a separation may be
effected. r
17. Key Words and Document Analysis. 17a. Descriptors
*Recycling, *Separation, Surveys
17b. Identifiers/Open-Ended Terms
*Resource recovery, *Municipal waste, Separation device, Recycling criteria
17e. COSATI Field/Group
18. Availability Statement
Release to public
19. Security Class (This
Report)
UNCLASSIFIED
20. Security Class (This
Page
UNCLASSIFIED
21. No. of Pages
110
22. Price
FOI?M NTIS-3B (1O-70)
USCOMM-DC 40329-P71
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TABLE 0_F CONTENTS
PAGE
PREFACE iv
I - INTRODUCTION 1
II - CONSTITUENTS OF SOLID WASTE 4
The Components of Municipal Solid Waste 4
Components which can presently be feasibly
Salvaged 6
Components which should probably be salvaged 9
III - STATE OF TECHNOLOGY 14
Current Solid Waste Disposal 14
Current and Proposed Solid Waste Recovery 17
The Technology of Materials Processing 20
IV - THEORETICAL CONSIDERATIONS 28
Mathematical Analysis 29
Sample Calculations 34
Conclusions 38
V - SCHEMATIC DIAGRAMS OF PROTOTYPE PLANT OPERATION *o
Introduction to Production Flow 40
Diagrams and Explanations of Basic Component
Modules in Operation 48
VI - BOWERMAN CLASSIFIER (As Originally Developed by
the Zurn Environmental Engineers) 65
VII - HEAVY-FRACTION SUBSYSTEM (AS originally Developed
by the ERIEZ Manufacturing Company) 77
VIII - COST ANALYSIS 95
IX - REFERENCES 96
X - APPENDICES
A. Typical Composition of a Composite Municipal
Refuse 105
B. Selected Centers of Relevant Technology 106
C. Alternative Method of Metallic/Nonmetallic
Separation 108
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LIST OF PLATES
1. Pilot Plant Flow Diagram 46
2. Schematic Floor Plan 47
3. Scalping Schematic 48
4. Grinding Schematic 50
5. Sieving Schematic 52
6. Shaping Schematic 54
7. Bowerman Classifier Schematic 56
8. Hydraulic Schematic 58
9. A. Typical Centrifugal Pump Head-Capacity Curve 60
B. Valve Sizing and Throttling Characteristics 61
10. Heavy-Fraction Subsystem Schematic 62
11. Bowerman Classifier, Stage I, Grinder 7%
12. Bowerman Classifier, Stage II, Sorter 76
13. Heavy-Fraction Subsystem, Pictorial Layout 79
14. Heavy-Fraction Subsystem, Overall Dimensional 80
Arrangement
15. Special Magnetic Drum 81
16. Side Discharge Baffle 83
17. Leveler 85
18. Metal Detector Coil 87
19. Plow for Metallic Rejection 89
20. Sorting Conveyor 91
21. Air Classifier 93
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PREFACE
This report is the product of the work performed under Grant No.
1-G06-EC-00292-01 from the Bureau of Solid Waste Management to
the Health Department of the County of Erie, State of Pennsylvania.
A team of experts, which provided competence in the fields of
Solid Waste Management, Civil Engineering, and Mechanical Engi-
neering, was assembled for the study by the Great Lakes Research
Institute (GLRI), under contract to the Health Department. This
team included the following individuals:
Prof. Frank R. Bowerman, School of Engr., Univ. of Southern Calif.
Dr. Ward W. Knockemus, Asst. Prof, of Chemistry, Pennsylvania
State University, Behrend Campus
Dr. Halit M. Kosar, Prof, of Engineering, Gannon College
Dr. David P. Spalding, Senior Research Assoc. in Chemistry,
Pennsylvania State University
This research group pursued three major objectives, as funded by
the research grant:
1) Determination and ranking of constituents contained in
municipal solid wastes in the order of beneficial re-
sults from their extraction, from the standpoint of
major present and projected disposal methods.
2) Survey of current proven methods of extracting constit-
uents from solid waste.
3) Draft of Specification for devices and subsystem for
extraction of constituents from solid wastes; development
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of a proposal for the design of an integrated pilot
extraction system.
The work reported here accomplished these objectives and has pro-
duced the design of a prototype installation for the development
of processes for the efficient recovery of useful components
from municipal solid wastes.
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SECTION I: INTRODUCTION
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This report is the result of a collaboration among the Erie
County Health Department, the Office of Solid Waste Management
Programs, and technical expertise assembled by the Great Lakes
Research Institute.
As the responsible agency for health maintenance in Erie County,
the Health Department has long recognized the importance of the
environment as a major determining factor in the quality of com-
munity health. Although cleaning up the environment is a costly
and long-range goal for a health department to pursue, Erie
County felt it could not afford to deal only with today's health
problems without planning for a better tomorrow.
This general consideration for the effects of the environment on
community health led to a more specific interest in the problem
of solid waste management. The Health Department felt that Erie
County would benefit greatly from a compiled summary of the state
of the art of waste treatment technology as it applied to var-
iously constituted aggregates of solid waste, particularly since
this up-to-date overview might lead to new insights in the treat-
ment and/or recycling of the solid wastes. In conjunction with
this initiative taken by the Health Department, the Office of
solid Waste Management Programs agreed to fund an investigation
under these general guidelines. The Health Department contracted
this investigation to a specialist research and consulting firm
in Erie, Pennsylvania, the Great Lakes Research Institute (GLRI).
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The project research team assembled by the GLRI first met on
August 5, 1970, under the chairmanship of the project manager,
Dr. Spalding, to share their knowledge on solid waste manage-
ment technology, and to develop a working plan with which to
fulfill the funded objectives. While it was agreed that all
members would contribute to the total effort, the prime respon-
sibility for determination and ranking of constituents (Objective
1) was assigned to Dr. Knockemus (see Section II), and the prime
responsibility for the technological review (Objective 2) was
assigned to Dr. Kosar (see Sections III and IV). Prof. Bower-
man assumed the prime responsibility for reviewing and integra-
ting these two efforts and for developing the proposal for the
integrated extraction system (Objective 3; see Preface, above,
and Sections V - VIII). The Plan adopted for accomplishment of
these project objectives was to (a) visit the centers of relevant
technology (b) study and selected references (c) prepare interim
reports on objectives 1 and 2 and (d) hold a project review meet-
ing to plan the accomplishment of objective 3.
As the review of relevant information proceeded, new insights
and ideas did indeed develop. The major inventive contribution
was made by Prof. Bowerman, who suggested a fluid settling tank
classifier which would preform comprehensive fractionation of
mixed solid wastes. Prof. Bowerman's idea has been incorporated
»
into a suggestion that a pilot, or prototype, plant be built to
study and demonstrate the feasibility of the new device. This
suggestion is included in Sections V - VIII.
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While much thought and preparation have been given to this sug-
gestion, in order to make it as detailed and workable a plan as
possible, this report has no pretensions of specifying every
detail of the project as a completely optimized and unalterable
decision. Where there are indicated quite specific building
parameters (brand names of components, power potentials and
the like), the reader should understand that these details are
"for instances," parameters which are recognized as useful pos-
sibilities, but which await the on-going development of the proj
ect for a final decision on their implementation.
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SECTION II: CONSTITUENTS OF SOLID WASTE
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Solid waste consists of practically anything solid that is dis-
carded, whether it comes from a home owner, hospital, restaurant
or corporation. Its domain is as broad as the range of products
man prepares from the raw materials provided by nature. Munici-
pal solid waste is a subclass of this enormous collection. It is
defined here to include garbage, rubbish, bulk wastes, and street
refuse generated by people in their homes and commercial estab-
lishments, but it excludes that generated by industrial operations.
Many studies have been made in this field, and the variation in
composition of such material in modern American cities is sur-
prisingly small (see graph below) (is).
Miscellaneous:
dirt, vacuum catch
adjusted moisture
Other Organic:
rinds7 meats,
fats, leaves,
grass, etc.
Other Manufactured:
plastics, rags,
leather, rubber,
paints, plastic-
coated paper,
wax cartons
CELLULOSE
(Paper products
and wood)
GLASS, ASH,
RAMICS
iTHER MFG'D. 5%
This composition is further broken down in Appendix A; for pres
ent purposes, however, the figures on the graph may be taken as
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typical. Slight regional and seasonal variations from this com-
position would not affect the major design considerations for
the pilot plant proposal (see Sections V, VI, and VII, below).
If the composition of these solid wastes is constant, notes
Richard D. Vaughan, formerly Director of the Office of Solid
Waste Management Programs, E.P.A., the quantities involved are
certainly not. The 360 million tons of solid waste presently
produced by Americans each year (of which 250 million tons
comes from households alone) will double within the next 15
years. Behind this statistic, Vaughan points out, grows the
urgency of two already serious national problems: what to do
with all this garbage, and how to replenish the resources wh'ich
are producing it.
Recycling - turning old wastes into new resources - presents a
neat, virtually ideal solution to both these problems: conser-
vation of resources is achieved, and a place is found for the
inundating mountains of solid waste. Unfortunately, economic
pragmatics, in light of current technological development, makes
complete recycling unattainable at the present time. The estab-
lishment of recycling priorities for various components of
solid waste must therefore continue to develop under the follow-
ing criteria:
1) The component is immediately reusable without altera-
tions or repair.
2) The component is made up of a material that originated
from a natural resource in fixed, short, or dwindling supply.
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3) A known technology can recover the original valuable
material in the discarded item at a reasonable cost.
4) The solid waste component has a chemical composition
that makes it potentially useful as a fertilizer,
soil conditioner, or fuel.
5) Current research indicates that a technology will
be available in the near future to transform the
currently useless item into something of value.
Under the above criteria, current proven technologies and pres-
ent markets establish the feasibility of salvaging the follow-
ing components of solid waste in many regions of the country:
1) Clean, bundled newspapers free of magazines, photo-
copy papers, or other treated papers containing.
clays, resins, starches, hot-melt adhesives, or
other objectionable additives. Though the market
fluctuates, this clean waste paper used for making
newsprint is worth $12-15 per ton.
2) Clean, corrugated cardboard, worth $7-12 per ton.
Of interest here is a recent conclusion by the
National Academies of Engineering and Science: "There
are no major technological limitations to the reuse of
newsprint and paperboard."
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3) Nearly all ferrous metals except "tin" cans (see
below for a discussion of tin cans). The mining of
the low grade iron ore taconite (25-30 per cent iron)
over the past dozen years signals the scarcity of a
high grade iron ore in the United States. Scrap iron
is worth one cent per pound ($20 per ton) , and junked
cars are reclaimed in many cities for ferrous metals.
However, the high capital cost of auto-shredding
plants dictates that they be found only in the large
urban centers that can provide a steady influx of
junk cars. Clean Steel, Inc., for example, in Long
Beach, California, shreds 500-800 cars daily. Although
there presently exists a shredder suitable for auto-
mobile processing in Erie County, residents junk only
16,000 cars yearly, which would not be sufficient to
economically justify the operation.
4) Aluminum, all forms, except possible "mixed" aluminum
cans (can ends are steel). At 1966 prices of 12 to 13
cents per pound an aluminum salvage program was not
economically self-sustaining. During mid-summer, 1970,
Reynolds Aluminum stated publicly that scrap aluminum
was worth $200 per ton (10 cents per pound) and paid 1/2
cent per aluminum can brought to their reclamation plants
Los Angeles collected more than a million aluminum cans
per month to supply some 25 tons of aluminum for reclama-
tion. The U.S. Reduction Company, East Chicago, Indiana,
estimates that a city would have to supply from 50 to
500 tons of aluminum per month before it would be con-
sidered a good source of secondary aluminum.
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Two factors, however, should make aluminum recycling
economically more feasible than in the past: (a) an
increasing amount of aluminum in municipal refuse
(b) a more effective recovery of aluminum cans due to
an increased degree of public awareness of the non-
degradability of cans coupled with a greater public
desire to cleanse the environment.
5) Rubber tires. In 1962, 16 percent (360,000 tons) of
the rubber used for manufacture came from discarded
tires. Each new tire (with a weight of about 20 pounds)
contains 2-5 pounds of reclaimed rubber. (Oddly enough,
government vehicles are required to have tires contain-
ing no reclaimed rubber). Reclaimed rubber is mechani-
cally masticated more quickly than crude rubber and is
well adapted to absorb fillers; other characteristics
make it easier to work with than crude or synthetic
rubber. The bead wire cannot be economically salvaged.
A rubber reclaiming plant in St. Louis pays $14 per
ton, although the price for old tires in Lcs Angeles
is $6.50 less per ton because of their relative abundance
6) Other Metals. Copper, even when surrounded with elec-
trical insulation, seems worth saving with the present
scrap price of 30-40 cents per pound. The copper alloy
brass is worth 25-40 cents per pound and should, along
with zinc and copper, be regarded as too valuable for
burial in a landfill.
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There are some solid waste components' having little or no cur-
rent value, which nevertheless, for the following reasons, should
probably be reclaimed:
1) Current research points to a technological break-
through that will provide a use for the component.
2) The component occurs in significant quantities in
the solid waste stream.
3) The component is easily separated from other solid
waste components.
4) The component as it occurs in the solid waste stream
is comparatively uncontaminated or is easily cleaned.
5) The component is valuable in one section of the U.S.
but not in another.
Components which fall into this category include:
1) Tin Cans. Municipal solid waste is about 5 percent
"tin" cans by weight. Erie County's production of
approximately 500 tons per day of municipal refuse*
would therefore yield about 25 tons of tin cans per
day. Cans from Los Angeles residents are separated
magnetically at a landfill site, burned, shredded,
and rail hauled to low-grade copper mining operations
in the Southwest where they are worth $50 per ton. The
high surface-area-to-weight ratio makes the shredded
*Source: "A Solid Wastes Management Plan for Erie County, Pa.'
Prepared by the Zurn Environmental Engineers for the
local governmental agencies of Erie County, through
the Board of the Erie County Commissioners.
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cans an excellent source of iron for the precipation
of copper from the copper sulfate leachate. East of
the Mississippi there are no copper mines, and trans-
portation costs make it unprofitable to haul cans
farther than a few hundred miles. Nevertheless, the
ease of separation (magnetic) and steady production of
a significant tonnage of tin cans make saving them
seem worthwhile.
2) Glass. In 1966, the U. S. packaging industry used
some 50 percent more glass than steel and aluminum
combined: about 8 million tons of glass compared to
5.4 million tons of steel and aluminum (5.2 million
tons steel, 0.17 million tons aluminum). The graph
on page 4 shows glass, ceramics, and ashes together
making up some 8 percent of municipal waste. On this
basis an estimated figure for the daily accumulation
of glass from municipal waste in Erie County is 40
tons. Sixty to eighty percent of the glass in domes-
tic wastes is from bottles of various types, ten to
thirty percent is composed of broken window panes,
and the remainder comes from TV tubes, fluorescent
lamps, and cut glass.
The glass-making industry has regularly used from
10 to 60 percent of salvaged glass or cullet as
a basic raw material (worth $15 a ton in 1967).
About one half of the cullet comes from
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scrap dealers; the rest from bottlers or manufac-
turers who use glass in the making of their products.
Salvaged glass must be free of contaminants, espe-
cially metals, and sorted according to color before
it can be used as cullet. Domestic refuse glass is
heterogeneous with respect to both color and compo-
sition. Current research also indicates that ground
waste glass can be substituted for sand in aerated con-
crete or processed into glassphalt, both used in making
road surfaces.
Inasmuch as the raw materials (sand, limestone, soda
ash) used in glass manufacture are plentiful and
cheap ($10-15 per ton), there is no easy market for ;
salvaged glass. It appears, however, that uses will
be developed to provide some kind of market for re-
claimed glass in the near future.
3) Plastics. Over the past 10 years plastics have taken
over packaging needs dominated for many decades by
paper, glass, wood, and metal. In eight years, from
1958 to 1966, plastics in packaging increased from
333 million pounds to 1.8 billion pounds, an increase
of 550 percent (cellophane is not a plastic and is
not included in these figures). Although the total
tonnage in plastics was only about 2 per cent of the
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total 52 million tons of packaging materials in
1966, plastics accounted for about 10 percent of
the dollar volume in packaging.
Municipal waste consists of about 1 percent plastics
on a weight basis, but the fraction of plastics in
landfills will increase over the years because of
its near indestructability. Most plastic material
does not degrade, disintegrate, or dissolve when left
to the forces of nature.
The two main types of plastic, thermoplastics and
thermo-setting plastics, are distinguished by their
reaction to heat. The former may be reshaped by
heat and pressure, while the latter, once formed,
cannot be melted and remolded. All the large vol-
ume plastics are thermoplastics, and if these can
be separated readily from the thermosets in munici-
pal wastes, recycling may be appropriate. Current
salvaging of plastics is limited to industrial and
"in-house" reclamation of rejects, trimmings, etc.,
where the type is known and the material is uncon-
taminated. Reclaimed plastics from industrial salvage
must be ground, melted, screened, blended, and pellet-
ized before sale. There is not a favorable outlook
for the extensive use of recycled plastics at the
present time.
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A brighter future seems more likely for plastics as
raw material for pyrolysis (see Section IV). Union
Carbide has patented products such as paste waxes,
polishes, lubricants, and adhesives obtained from
the pyrolysis of polyethylene resin. Pyrolysis breaks
down plastic materials into a variety of simpler mole-
cules, similar to those in crude petroleum. It seems
reasonable to save waste plastic, not for recycling as
plastic, but as a feedstock to be pyrolyzed into use-
ful compounds. No demand for waste plastics for
pyrolysis exists presently, but perfection of the
technology is a near certainty, and subsequent con-
sumption of waste plastic seems likely.
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SECTION III: STATE OF TECHNOLOGY
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As recycling has gained wide conceptual acceptance, technology
has responded with a change in its approach to the solid waste
problem from an emphasis on disposal to an emphasis on recovery.
Nevertheless, as the balance begins to tip in favor of recovery,
economic considerations have produced a continuum of treatment
processes which combine recovery and disposal in nearly every
measure. As development proceeds towards recovery, new processes
must be introduced; and one of the most fruitful sources for
these new processes is, of course, the technology already de-
veloped in other fields for materials handling. Thus, following
N. L. Drobny, et. al. (8), we may identify three major areas of
consideration in our technological review:
1) present processes used essentially for solid waste
disposal;
2) present and proposed processes for solid waste recovery;
3) the material processing technology as developed in
other fields.
Current disposal practice for municipal solid wastes follows one
of three procedures: (1) sanitary landfill, (2) incineration,
or (3) composting*. Two unit processes are common to these stand-
ard systems: densification and size reduction. In densification
the weight of the material per unit volume is increased; scrap-
metal baling is an example of such an operation. In size reduc-
tion individual particles of waste material are simply reduced in
size. Rock crushers, mills, and sink-mounted garbage grinders
are examples of standard equipment used to perform this operation.
*See footnote and explanation for this categorization, page 16.
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To date, most municipal solid wastes in the United States have
been disposed of in landfills. Even after other disposal methods
have been applied, a residue remains which must ultimately be
disposed of by landfilling. For this reason, it appears that
landfills will continue to be required to a certain degree in the
future. The main unit process for landfilling is densification.
The volume of the waste must obviously be reduced to maximize the
use of available landfill capacity. In most sanitary landfills,
crawler or rubber-tired bull-dozers have been used for this pur-
pose. In the experimental landfill operation in Madison, Wiscon-
sin, both densification and size reduction are employed. Munici-
pal refuse is first milled by a vertical rotor multi-stage mill,
then densification is applied at the landfill site by a compacting
bull-dozer. The pre-landfill milling produces particulate material
which is readily compacted in the landfill.
For disposal of solid wastes by incineration both densification
and size reduction operations may be applied. Size reduction is
generally used on bulky or oversized items in the municipal waste.
Densification is necessary only if it is desired to produce a
briquette-type fuel from the solid wastes. For such purposes,
the refuse must be sorted to remove non-combustibles, ground
for uniformity, and dried, as well as compacted. Studies con-
ducted on such operations now being tested in Western Europe
(33) show that one ton of incineratable briquettes with a cal-
orific value of approximately 7,500 BTU per pound can be produced
from six tons of normal refuse, leaving five tons to be disposed
of by other means. Heat recovered from incinerators has been
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used to heat schools, offices, and houses, as well as to drive
turbogenerators. Metal recovery from incinerators has also
been developed (38, 24).
Composting, which has been practiced in Europe for many years,
has not seen significant commercial success in the U. S., prob-
ably because the orientation of U. S. agriculture has been
toward faster acting and more specific commercial fertilziers.
Moreover, compost has difficulty meeting the precise chemical
demands imposed by the highly productive and technical agricul-
ture that exists in the United States.*
For composting, densification is not needed. Size reduction,
which is usually desirable, may be effected by shredding the
refuse before it goes into any process to produce compost.
Size reduction processes differ from plant to plant. In some
plants, which use can- and bottle-free input garbage, no sal-
vage is necessary; and the total refuse is milled. In the
Altoona (Pa.) Composting Plant (an experimental station of
the Fairfield Engineering Company, see note 16), for example,
the primary mill is a hammermill, which produces an average
particle size of 0.75 inch. Ferrous particles are separated
from the milled refuse by a magnetic drum separator, and
the residue is converted into fine particle size pulp by a wet
grinder. Other pre-composting separation methods may also be
*It is for this reason that we have presently placed composting
under the methods for solid waste disposal, although an increased
market for compost in the future would justify a reclassification
of composting as a useful process for recovering solid wastes.
The point, in any case, is academic..
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applied for removing non-magnetic metallic particles and glass.
In Europe, for example, hand separation is practiced for the
removal of large sized paper, cardboard, rags, metals, and
bottles. This material may then be converted to compost in
a digester by the action of aerobic thermophilic bacteria,
producing a weight reduction of approximately 30 per cent and
a volume reduction of 80 per cent. The gray-black product
that is produced in 3-5 days is practically odorless and
attracts no insects or rodents.* The removal of shredded plas-
tic (which is easily accomplished after digestion) gives a more
homogenous product; drying and pelletizing produces B-B-sized
particles with a carbon-to-nitrogen ratio of 20 to 1. Such
material is useful as a soil conditioner, but is unsuitable
for marketing as a fertilizer. The compost can be enriched
through the addition of sewage sludge or animal wastes; numer-
ous tests reveal that no pathogenic organisms survive the sus-
tained heat (140-160° F.) of the digester process. The Metro-
politan Waste Corporation in Houston, Texas (39, 42), was able
to process 30 per cent (300 tons per day) of the total waste of
Houston into compost, before it had to be closed down recently
for lack of funds.
Processes which emphasize the recovery of solid wastes have so
far been largely confined by their economic viability to deal-
ing, only with certain components of the wastes. So it is that
individual industries have gone quite far toward regaining a
specific usable input resource from variously constituted col-
lections of solid waste, while the treatment of general, mixed
waste to reclaim a variety of products has lagged behind.
*Source: Private Communication from Altoona FAM, Altoona, Pa.
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The most thoroughly proven recycling operations to date are those
which begin with wastes which never become a part of the general
lump called mixed municipal solid wastes. Thus, while not immed-
iately usable as input for manufactured items, they are already
in a first approximation to purified form; and their consistency
is qualitatively different from that given in the graph on page
4. Scrap cellulose, for example, available in such diverse
forms as corrugated paper boxes, newspaper, magazine paper,
brown paper, mail, paper food cartons, tissue paper, and wood,
has long been reclaimed for making newsprint fiber, such as in
the highly successful operation at the Garden State Paper Company
in Pomona, California (17). Cellulose may also be used as fuel
for the generation of energy, converted to compost (see pages 16-17,
above), or introduced as raw material for pyrolysis units (see
page 1$ below). Scrap metal - brass, copper, aluminum, iron,
steel, etc. - has for many years been a prime resource of the
metals industries.
A few relatively new recycling operations begin with the mixed
municipal solid wastes themselves. Three installations exist in
the United States today which are significant from this point of
view:
THE ALTOONA (PA.) COMPOSTING PLANT (16), mentioned above
(page 16), successfully converts a major portion of
municipal garbage to compost. (This may be justi-
fiably called recovered waste; see note, page 16.)
THE BLACK CLAWSON COMPANY IN FRANKLIN, OHIO (2), has
developed a pilot facility for the city of Franklin,
which is an attempt to provide separation and recovery
of cellulose fiber, ceramics, and certain metallic
materials. This facility is being funded by the
Office of Solid Waste Management Programs of the
Environmental Protection Agency.
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THE U. S. BUREAU OF MINES IN PITTSBURGH, PA., (35) ANP
IN COLLEGE PARK, MP. (6): Studies at the Pittsburgh
Energy Research Center indicate that both municipal
and industrial wastes can be pyrolyzed (heated in
the absence of air) at 900° C to yield oils market-
able as fuels or as sources of such chemicals as
styrene; combustible hydrocarbon gases which can be
used as fuel in the pyrolization plant itself; and
carbon black. Studies in College Park are devel-
oping a process which aims to recover the mineral
components from incinerator residues.
Four systems are in the design or proposal stage which also
begin their operations with mixed solid wastes:
THE ALUMINUM ASSOCIATION OF NEW VORK, N.V. (10), has
designed an integrated municipal refuse recycling
plant which combines the current incinerator and
pyrolysis technology with the Bureau of Mines
mineral recovery unit (6) to produce fiber, heat,
and recovered mineral components.
COMBUSTION POWER, INC., IN MENLO PARK, CALIF. (11),
has completed pilot plant studies and is propos-
ing a full-scale plant for the conversion of
municipal solid waste to electrical energy by
means of a fluid bed combustion chamber feeding a
gas turbine generator. Combustion Power is also
being funded by the Environmental Protection Agency.
HERCULES, INC., IN WILMINGTON, PEL. (13), will uti-
lize both the technology developed by the Fair-
field Engineering Company, Marion, Ohio, for
converting waste cellulose to compost (16), and
the pyrolysis technology of the Bureau of Mines
(35).
MOWSANTO'S ENl/IRO-CHEM SYSTEM IN ST. LOUIS, MO. (20),
the so-called Landgard System, has been developed
through a 35-ton-per-day pilot plant and is a
completely integrated plant based on the Bureau
of Mines pyrolysis technology.
Unfortunately, it is clear from the above that the output of
recycling operations which begin with the mixed wastes does
not in general meet the input requirements of those which
deal with the refinement of selected waste components. The
- 19 -
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tentative links which have been established proceed, for example,
from mixed solid waste to cellulose products, or from mixed
solid waste to ferrous metal products. But much work remains
to be done on the development of a comprehensive fractionator-
classifier which can feed simultaneously into several different
material-specific recycling systems. One such classifier that
comes close to meeting these needs is an air classifier (see
page 23, below), which will separate a uniformly-sized mixture
into two components on the basis of different particle density,
or a uniformly dense mixture into two components on the basis
of different particle size. Another is the system being de-
veloped by Black Clawson in Franklin, Ohio (2), which has, in
effect, placed a number of different single-component sorting
mechanisms under one roof, to finally obtain from the mixed
wastes several different components suitable for input as in-
dustrial raw material.
It still remains true, however, that the widest technological
gap in an economically feasible conversion of mixed municipal
solid wastes to usable resources is precisely at the point of
primary, comprehensive classification. It was toward develop-
ing such a classifier, with large capacity and broad capability,
that the Erie County Health Department directed its attention.
At- an early stage of its exploratory work into the technology
of material processing in other fields, the GLRI research team
recognized the potential significance of mining techniques
applied to solid waste extraction. Indeed, once the analogy
is made, it is difficult to understand that it was ever ignored:
- 20 -
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Solid waste might well be considered an impure ore, which must
be mined and refined (i.e., recycled) before it can be used
as raw material for manufacturing. And solid waste recycling,
like mining, will always be a matter of separating the desired
materials to some statistically approximate degree of refine-
ment, to produce a material salable for maximum profit at an
overall minimum cost. From exhaustive sourcebooks on mining
technology (4) numerous methods of ore separation and refine-
ment which might also be applied to solid wastes have been
identified. These methods are based on inherent or induced
differences in the physical properties of the components of
the solid mixture. The major variable properties of the com-
ponents which may be exploited in separation processes are
color, luster, size, shape, strength, brittleness, structufe,
texture, surface characteristics, specific gravity, magnetic
susceptibility, electrical conductivity, radioactivity, and
susceptibility to decomposition by the action of various
agents. These properties of individual components may also be
changed to varying extents by physical and chemical treatments
such as drying, oxidation, and the like. Applicable separation
methods are as follows:
Crushing
Crushing is normally done in two or three stages, depending
•upon the reduction necessary to attain grinding-mill feed-size
and upon the capacity of the crusher. Jaw and gyratory crush-
ers are the usual primaries. Metallic ores are, in general,
too hard for other types. Various gyratory and cone-type
- 21 -
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crushers are almost universally found as secondaries.
Hammermills are also used as secondary crushers for rocks
ranging in hardness from soft limestones to clay, but they
can as well crush harder rocks for concrete aggregates.
Grinding
Grinding is the final stage in size reduction; the grinder
must reduce material to a limiting size. The most economical
way to grind rock is to rub it in a thin layer between hard
surfaces, under pressure sufficient for cracking.
Screening
Screening is a separating process primarily based on particle
size. Screening efficiency is measured in two general ways:
One method compares the proportion of over-sized material
that will pass through a given operating screen, with the
proportion of the same material from some dried standard
test lot that will pass through a test screen of the same
aperture. Alternatively the comparisons are made on propor-
tions of undersized material. Commercial screens are class-
ified by their respective methods of effecting relative
motion between the feed bed and the screening surface, as
follows: (a) Fixed Screens, (b) Revolving Screens, (c) Shaking
'Screens, and (d) Vibrating Screens.
Fluid Classification
In fluid classification separations are effected by the
colinear opposition to gravity of drag forces produced on a
particle by its relative motion through a fluid. Settling
- 22 -
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velocities (positive or negative) are a function of size,
shape, and specific gravity. One typical design for fluid
classification incorporates a cylindrical tube, or sorting
column, through which particles fall relative to a rising
current of water. Whether the particles fall or rise rela-
tive to the column wall depends upon the parameters of the
individual particles and on the rising velocity of the water.
Another, more recent design is the Air Classifier developed
by the Stanford Research Institute (1), which separates par-
ticles on the basis of density by dropping them through a
horizontal crosscurrent of air (see page 20).
Fluid - Solid Separation
For the separation of fluids from solids, filters and dust
collectors may be employed. Filtration performs separation
by causing the fluids to pass through a finely perforated
septum that will not pass the solids. Essentially this is
ultrafine screening. As in screening, friction is the prin-
cipal force resisting passage. The driving force may be
gravity, but usually it is a differential fluid pressure on
the two sides of the separating filter. Vacuum filters are
generally used in handling wet pulps, while dry filters are
employed in dust collection. Centrifuges and cyclones may
also be applied to fluid-solid separation.
Washing and Scrubbing
Washing and scrubbing are used to remove minor, fine constitu-
ents from the main particles, so that the latter may be accur-
- 23 -
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ately sorted.
Sorting
Both hand sorting and mechanical sorting may be used on solid
waste, although hand sorting was abandoned years ago in the
mining industry. In either case, the materials must be loose
and clean enough to be picked out according to the given dis-
tinguishing property. For this reason, crushing, grinding,
screening, fluid classification, and washing may all be nec-
essary prior to the sorting. Mining technology has a variety
of specialized mechanical sorters or pickers which may find
application in solid waste recovery, including:
1) The Spiral Picker, used for separating anthracite
from flat slate;
2) Slotted - Screen Pickers, used for separating
anthracite from flat slate and middlings;
3) Ziegler Pickers, used for separating flat slate
from rounded particles;
4) The Ayers Picker, also used for separating flat
slate from rounded particles.
Mechanical sorters utilizing color or radioactivity have
recently been introduced. Color differences or radioactiv-
ity is detected by a sensing device, which may operate an
air blast to move a particle to a desired location.
Gravity Concentration
Separation of material according to specific gravity may be
accomplished by jigging*, tabling*, spiralling*, and heavy
media separation, as well as by fluid classification (see
pages 22-23, above).
*Mining terminology
- 24 -
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Magnetic Separation
Magnetic separation can be employed dry or wet, and it is
the most effective separation method for ferrous materials.
A mixture of particles which respond differentially to a
magnetic field is introduced into the field so that all the
particles are equally subjected to the field and to another
force or forces, such as gravity, friction, inertia, centrif-
ugal forces, or fluid resistances, directed at an angle to
the magnetic field. Pulley-or drum-type magnets are used for
relatively coarse feeds of highly magnetic materials. Weakly
magnetic materials, on the other hand, require high intensity
machines and slow, even feed rates to attain the small airgap
necessary for separation. Non-magnetic and weakly magnetic
minerals containing iron can be separated by a magnetic drum,
but in such cases particle diameters should be less than 3/4
inch.
Electrostatic Separation
Electrostatic separation depends upon differences among minerals
in the mobilities of their free electrons when the mineral
particles are in an electric field. Materials are classified
electrostatically as conductors (high electron mobility),
insulators, or dielectrics (low electron mobility), or semi-
conductors (much higher electron mobility than the dielectrics,
but materially less than that for the conductors). Within
each of these categories there is a range in the electron
mobilities of various materials; but, for separating applications,
- 25 -
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this range is sufficient only for the dielectrics. Minerals
are conductors, while most other materials are dielectrics.
Because of the direct relationship between field force and
particle volume, the larger particles of a given mineral de-
viate more than do the smaller; and a rough sizing can be
obtained. The application of electrostatic separation is
presently limited to particles passed by 10- to 150-mesh screens
Flotation
Flotation is a process for rendering a mixture of finely
ground minerals (capable of passing through a 20-mesh screen)
susceptible to gravitational separation. This is done by
inducing selective attachment of gas bubbles to one mineral
species while the mixture is submerged in water. Although,
theoretically, there is no limit to the number of different
kinds of minerals that can be separated by flotation, exper-
imentation has proved that the only naturally flotable min-
erals are the solid hydrocarbons. Air bubbles adhere to clean
surfaces of these minerals in pure water. When bubbles adhere
to other minerals in water, organic contamination of the par-
ticle surfaces is positively indicated. The minerals that can
be coated with pure hydrocarbon oil in water are hydrocarbon
minerals such as coal, sulphur, graphite, and a group of sul-
phides. Although flotation is quite complex in operation, it
is one of the most modern, efficient, and widely applicable
methods of separation.
- 26 -
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Having taken the proceeding account into consideration, the
GLRI research team (see Introduction, Section I) proposed the
incorporation of some of the above elements into the design of
a pilot plant for the study of the comprehensive fractionation
of municipal solid wastes. The major innovation and key feature
of this design is the primary, or Bowerman Classifier, so named
in honor of Frank R. Bowerman, the member of the study team who
contributed the design. The output material from this fluid
classification process can serve as input material to fiber,
metal and glass recovery, composting, energy production, and
pyrolysis systems. Thus, this output will be compatible with
the significant other proposed pilot facilities in the nation.
- 27 -
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-------
SECTION IV: THEORETICAL CONSIDERATIONS
7 A
-------
The Bowerman Classifier makes use of a physical phenomenon des-
cribed by Stoke1s Law. This law states that particles having
the same size and shape but different densities will have differ-
ent settling velocities according to these densities while fall-
ing through a quiescent fluid. The principle may be extended to
particles falling through a fluid flowing with a low velocity.
Therefore, particles of similar size and shape falling through
a fluid flowing at low velocity in a settling tank will be depos-
ited on the bottom in different locations. All other factors
remaining constant, this scattering of the settled particles will
be governed by the densities of the particles and by the velocity
and the density of the flowing fluid.
A more precise technical analysis follows.
- 28 -
-------
In falling freely through a quiescent fluid, a particle accel-
erates until the frictional resistance, or drag, of the fluid
equals the impelling force acting upon the particle. There-
after, the particle settles at a uniform rate.
The impelling force is equal to the effective weight of the par-
ticle, i.e., its weight in the suspending fluid.
Therefore,
Fj - (P s - P) gV, (1)
where F is the impelling force, g the gravity constant, V the
volume of the particle, and p and p are respectively the mass
density of the particle and fluid.
The drag force F of the fluid, on the other hand, is a function
of the dynamic viscosity p and mass density p of the fluid and
of the velocity V and a characteristic diameter d of the par-
~>
ticle. To be fully representative, this diameter must reflect
(1) the orientation of the particle with respect to the direction
of its motion, represented, for example, by the area of the pro-
jection of the particle cross-section onto a plane at right angles
to the direction of the particle motion, and (2) the relative
frictional surface of the particle in contact with the fluid
- 29 -
-------
represented, for example, by its surface area in relation to its
volume. Dimensionally , therefore, Fp = (vs, d, p, y) or,
designating dimensional relations by square brackets,
[FD] - [vfdY PP y«].
Introducing the fundamental units of mass m, length i , and time t,
of the various parameters into this equation,
and solving for x, y, and p in terms of q,
FD = vs2d2p(vsdp/y) - vs2d2q
-------
(Ps-P)gV = CDAcPVs2/2,
2g P^-Q V
v . [ Jf . tls__p . _
CD P Ac
Thus, for spheres,
V = Trd3/6 and AC = Trd2/4,
so that
4 g P -P 1/7
vs - [ - - - • -a- • d]1/2. (5)
3 CD p
For eddying resistance at high Reynolds numbers (R - 103 to 105),
Crj becomes practically constant with values of 0.4 or 0.5 over
wide domains of R,* and
r g jT c^
v_ = [ — • • -s— • d]1/^, (6)
5 3 0.4 p
or,
3 0.5
*Zahm, A.F., and Roshko, A. "Experiments on the Flow Past a
Circular Cylinder at Very High Reynolds Number." Jour. Fl
Mech., Vol. 10 (1961), p. 345.
- 31 -
-------
For viscous resistance at low Reynolds numbers (R <0.5),
Cn = 24/R, and n D -
U ^ M - H *v , i /
vs =
(8)
y
Equation 8 is the Stoke's law.
For particles having same size and shape, but different mass den-
sities, falling through the same fluid flowing at a uniform velocity,
the terms Cn, V and Af in Equation (4) will be constant and it reduces
to
(9)
where,
K-
1/2
= constant.
D
Therefore, two particles of same size and shape having different
densities will have different settling velocities and their inter-
relationships may be represented by the following expression
1/2
V
sl
s2
(PS2-P)
(10)
where, v and v 9 are the settling velocities of particles hav-
s 1 s /
ing densities psl and ps2, respectively.
Figure 1
d
Figure 2
32
-------
The paths taken by discrete particles of same size and shape but
different densities, settling in a horizontal- flow basin are shown
in Figure 1. They are determined by the vector sums of the settling
velocity vg of the particle and the displacement velocity v^ of
the fluid in the basin as shown on the free body diagram in Figure 2.
Settling time of the particle
h
t = v7~ (11)
The horizontal distance travelled by the particle in this time,
S = t x vd (12)
h x
(13)
for any flowing fluid with uniform velocity of flow in the settling
basin, both v^ and h are constant, and, therefore,
S = K'/vs, where K' = hvd> (14)
1/2
Hence, fl_ _ Vs2 _ (Ps2 (15)
S2 ~ VS1 " (Psl-P) 1/2
where, si and s2 are the horizontal distances traversed .by two
particles of same size and shape having densities psj and PS2»
respectively in a fluid of density p.
The distance s may be increased by increasing either the depth of
the settling basin h or the velocity of the fluid flow, v,. But,
for ideal settling basin (where all the particles are arrested
within the basin) v , ^ v . Therefore, s should be manipulated
mainly by h, whereas v, should be controlled by the minimum of the vs
" 33 " -
-------
and settling basins with greater depth are expected to give a
better scatter of the particles of same size and shape but hav-
ing different densities.
SAMPLE CALCULATION
Let us assume that the municipal solid wastes have been crushed,
shaped, and separated into uniform spheres of 2-inch diameter and
allowed to drop into a rectangular settling tank with dimensions
20' x 5' x 5' deep. The fluid in the tank is water at 20° C, which
has a density of 62.4 Ibs./ft. and a kinematic viscosity of 1.0105
-22
x 10 cm /sec., and which we assume is moving with a displacement
velocity of 2 ft/sec. Let us further assume the induced particles
move together with the water, i.e., there is no relative motion
of the particles and the water in the direction of current flow.*
Selected components of solid wastes and their densities are given
in Table I.
TABLE I
Densities of Selected Components of Solid Waste
Component Density in Ibs/ft.
Glass 125
Paper 44-75
Ferrous Metal 488
Brass § Copper 532
Aluminum 169
Plastic 56-100
*This is an experimentally valid simplification, since accelera-
tion of the particles to the velocity of the current takes place
in a very small fraction of a second (see A. F. Taggart, "Sedi-
mentation Method of Mining," in Reference 4-a).
- 34 -
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SOLUTION
vs . d
The Reynolds number, R = .
Here d = 2 inches = 2 x 2.5 = 5 cm.
v = 1.0105 x 10"2 cm2/sec.
For high Reynolds numbers (see page 31) C for spheres becomes
practically constant with a value of
CD = 0.4 for R = 2,000 to 10,000, and
CD = 0.5 for R = 20,000 to 200,000.
For these Reynolds numbers, the corresponding limit velocities
= ^LJ
s d
v R
would be given by v —r-, so that
for C = 0.4,
vg » 4.04 cm/sec = 0.135 ft/sec to 20.21 cm/sec = 0.675 ft/sec;
for CD = 0.5,
v = 40.4 cm/sec = 1.35 ft/sec to 404 cm/sec = 13.5 ft/sec.
The settling velocity for the particles of any one of the compon-
ents may be calculated from Equations (6) and (7), while the set-
tling velocities for the particles of other components may be found
out utilizing the relationship shown in Equation (10).
Let us find out the settling velocity for glass. By iterative
examination one may observe that C = 0.5 should be used, and
- 35 -
-------
v (glass) = [-1 x ^ x 125^J2'4 x -^]~- 3.8 ft/sec
To get a better scatter, let us assume a depth of 10 ft. for the
tank instead of 5 ft.
The time taken by the glass particles to reach the bottom of the
tank is
t = =~ = 2.63 sec.
g 3.8
The horizontal distance traversed by these glass particles in
time t in a fluid moving at 2 ft/ sec. is
o
S = 2.63 x 2 = 5.26 ft.
g
The horizontal distances traversed by particles of other solid
waste components may be obtained from Equation (15).
DISTANCES TRAVERSED BY PARTICLES OF OTHER DENSITIES
1/9
PAPER (most dense): 5.26 x [l^"6.^] = 11.75 ft.
•t / O
FERROUS METAL: 5.26 x [125"62'4] - 2.02 ft.
1 / 9
BRASS, COPPER: 5.26 x tHo'' 1>92 ft'
125-6241/2
ALUMINUM: 5.26 x [ " f' A " 4.04 ft
169-62.4
PLASTICS (most dense): 5.26 x [125'62'4] = 6.80 ft
J L100-62.4J
- 36 -
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Simple sedimentation rate studies were conducted and indicate
that the shape factor is indeed significant (34). Particles of
various density and configuration, as described in the table and
notes below were introduced into a glass tube 45 inches ( = 3.75
feet) high and 1-1/2 inches in diameter, containing approximately
one quart of water. Their settling times tg , in seconds, are given
in Table II (25).
Flat (20 x 20 mm)
Spherical
Crumbled Sheet
Ribbon Twisted
(7 x 50 mm)
lead2
7
2
2
4
TABLE II
zinc^
17
no data
4
5
aluminum** glass"
43
2
6
31
36
3
6
36
20 x 20 mm piece crumbled for all trials
lead sheet 8/1000 inches thick
zinc sheet 6/1000 inches thick
v
tin foil 1/2000 inches thick
aluminum sheet 5/1000 inches thick
4-mm spheres weighing 0.092 grams each
By utilizing the proceeding data, the distances traversed by
these particles in a settling tank of depth h with current velocity
V may be computed from the following formula:
S = C^-4-) (V) (16)
Here S is the distance in feet. This is clear, since the settling
time from any height is just
- 37 -
-------
37.4
10.7
10.7
21.2
91
no data
21.2
26.6
230
10.7
32
165.4
192
160
32
192
£ • 3-7T7T ' »V3-75'
S S
where v is the settling velocity (assumed constant).
o
Thus for example, in a settling tank 10 feet deep with a current
velocity of 2 ft/sec, the particles in Table II would traverse
the following distances (in feet):
lead zinc tin aluminum glass
Flat
Spherical 10.7 no data 10.7 160 160
Crumbled Sheet
Ribbon Twisted
The preceeding mathematical analysis, as well as the calculations
based on the preliminary experimental work described above, indi-
cate that:
1) The proposed Bowerman Fluid Classifier will work to
effectively separate organic from heavier inorganic
fractions. Depending on the sizing operations that
can be developed, the fractionation of the heavy frac-
tions on the bottom of the classifier will be more
or less efficient. It may be difficult, however, to
separate the ferrous and brass § copper from each
other due to their close densities. It was decided,
therefore, that a subsystem would be needed for com-
pletion of the fractionation of the heavy residue
(i.e., magnetic separation of the ferrous metal, etc.).
- 38 -
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2) The tank length must be quite large to allow the
paper particles to get settled. Paper and plastic
particles should be allowed to flow out from the
tank with the effluent and separated from water by
screening.
3) Particles spherical i'n shape traverse similar hori-
zontal distances and settle in similar stations if
they are of similar densities. Particles other than
sperical in shape traverse dissimilar horizontal dis-
tances whatever their densities, and settling stations
overlap. Although it is not possible to reduce solid
wastes into perfect and uniform spheres, the minimizing
of flat shapes and the sieving of particles into size
categories would reduce the "drag" effects on flat
shapes to a minimum.
- 39 -
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-------
SECTION V: SCHEMATIC DIAGRAMS OF PROTOTYPE PLANT OPERATION
-------
This section is intended to give the general reader a reasonably
thorough, though unmathematical description of the possible opera-
tion of the various components of the proposed pilot plant, making
use of the theoretical considerations outlined above. What follows
should in no case be construed as an engineering diagram from
which to build, or even as a finalized guideline from which these
engineering specifications might be directly developed. Indeed
the description does not necessarily represent all our latest
thinking on details of the operation, though many specifics which
are here included would undoubtedly find their way into a final
design. Nevertheless, these schematics do incorporate our gen-
eral, fundamental conceptions of what we intend to do and how we
intend to go about doing it. When we become less than specific,
it is invariably because the technology of the system is not com-
pletely understood--obviously, the entire rationale for a prototype
plant stage would be removed if this were not the case. What we
do build in now is a large measure of flexibility, and it is our
desire to make this flexibility a meaningful building block that
has motivated us to identify the form it takes at every turn.
The careful reader will note from comparison of the schematics
with other sections (VI and VII) of this report that we have not
always allowed our continuing thinking to be constrained by com-
plete consistency of detail. Indeed, such constraint would be
most unwise and misleading at a point when no component of the
design can be considered final. Thus, for example, a "scalping"
- 40 -
-------
step has been schematized (Plate 3) and added to the operational
flow chart (Plate 1), which is not provided for in the plan on
page 75. This sorting of the largest and smallest objects of
refuse may prove to be a desirable first operation, or it may
turn out to be redundant. So with the variable-speed pump as
specified on page 70: the hydraulic schematic of the Bowerman
Classifier in this section (Plate 8) proposes an alternative
solution to the problem of providing for different current velo-
cities in the Classifier tank (see Plate 7). One of these systems
may suffice by itself, or it may be the most effective scheme will
incorporate both systems in tandem. A number of different sieving
methods have been proposed (compare Step II in this section and the
diagram on page 75). Finally, all these variations imply a multi-
tude of possibilities for the final setup configuration of the
pilot plant as a whole. Plate 2 furnishes one possibility; pages
75-76 provide another.
The reader is encouraged to follow the flow diagram (Plate 1) as
the exposition proceeds and refer to the tentative floor plan
(Plate 2) for a general understanding of how this sequence might
be set up. The general account given here is followed by a more
complete, step-by-step series of diagrams showing the components
of the pilot plant as they will function in operation.
It has been noted above (Section IV) that solid waste particles
must be carefully sorted with respect to size and given an approx-
imately spherical configuration, before the Classifier can be
expected to perform well-defined segregations based on density. In
- 41 -
-------
the prototype plant this may be carried out in up to four differ-
ent preliminary steps. Most particles of the raw, mixed refuse are
first introduced into a trommelling device (Step I, Scalping) where
they are roughly segmented into three size-categories. Particles
in the two largest size-categories proceed to a grinder (Step II),
where they are ground small enough to join the smallest particles
from Step I for more precise sizing in a vibratory screen (Step
III, Sieving). The very largest particles entering the prototype
plant, such as automobile tires, will initially be fed directly
to the grinder; and this grinder output will then move on with
the rest of the wastes to the vibratory screen. This sieving step
produces a second output branching. The largest particles return
to the grinder (Step II), while most of the others continue to a
shaping mill (Step IV). Since, however, the tolerances of varia-
tions from spherical shape permitted by the Bowerman Classifier are
not precisely known, some sieved particles may skip directly to the
Classifier instead of going through the shaping mill. Particles
which are shaped in the mill may require a second sizing in the
vibratory screen before moving on to the Classifier (Step V) .
Before the particles are introduced into the Classifier, the flow
speed of the tank fluid is checked by introducing colored dyes
or, perhaps, merely floating wood chips. Particles of roughly
homogeneous size are then placed at the top of one end of the tank
and allowed to settle to the bottom while being carried along by
the current. Materials of different density--except those too
light or too fine to sink into the fluid--settle along the bottom
in different locations. Some of the particles carried beyond the
- 42 -
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tank area by the current may be deposited in subsequent runs of
the Classifier at lower tank-fluid velocity.
A post-Classifier step is included in the pilot plant for further
sorting of high density "heavy" material (Step VI, Heavy-Fraction
Subsystem). Particles collected from the end of the Classifier
tank nearest the input (see graph below) are sent to a subsystem
designed by the ERIEZ Magnetics Corp., which will separate the
input material into quantities of ferrous metals and nonferrous
metals, and two different-density groups of nonmetallic substances.
HEAVY FRACTION
(Percentages of mixed, municipal solid waste by weight) (18)
TIN CANS 5%
HEAVIES
15%
OTHER METALS 2*
GLASS 2%
STONE, CERAMICS 1%
OTHER
WASTES
ASHES, DIRT 5%
85%
Although the individual principles of operation have been proved
in other applications and configurations, this step is an integral
and legitimate part of the pilot plant both for its novel config-
uration of the components to provide great flexibility of adjust-
ment for handling a wide range of experimental input material,
and for its demonstration value as one of many subsequent refine-
ment operations which may proceed after the initial separations
of the Bowerman Classifier.
- 43 -
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A few final observations are necessary before we commence with a
closer look at each of these steps. First of all, while each of
the basic components of the essential equipment is listed and
briefly described in the schematics, we make no attempt to show
such auxiliary equipment as electrical switch gear, power supply,
water supply, drainage, lighting, ventilation, safety protection
and the like. Such installations must, of course, be taken into
careful consideration in the final engineering specifications for
the pilot project.
Secondly, each of the modules in the flow diagram (Plate 1) must
not be thought of as a unique and nonrepeatable step, but rather
as a schematic step which may in practice represent a multiple
series and/or parallel application of the step. This applies
especially to the Bowerman Classifier, which, on account of its
many variably-controlled parameters, may be used to produce out-
put material with a number of different characteristics. Thus,
for example, particles dropping into the basket nearest the input
conveyor on the first run might be fanned across the entire tank
bottom on a second run merely by increasing the fluid velocity in
the tank. Or, the Classifier might be run with fluids which
would impart special useful properties to the output material.
If, for example, the Classifier tank was filled with a fuel oil
such as kerosene, separated paper, plastics, and fiber would have
uniquely beneficiated properties as slurried fuel, due to their
immersion in the liquid.* Bottles, cans, and other metals collected
* This may also be accomplished by spraying the fuel oil onto the
material on the traveling screen with the shower pump.
-------
from the same tank might be run through a rotary kiln furnace,
where the oil wetting their surfaces would probably provide
sufficient fuel to burn off labels, burn out liquid or solid
residues in the containers, and make the reclamation of steel
by magnetic separation or aluminum by ballistic separation from
the glass a more feasible procedure. Similarly, the use of a
nonexplosive solvent such as trichloroethylene as either tank
fluid or liquid spray at the traveling screen (see Step V, page
57) would degrease the collected paper and thus make it more
amenable to reuse in reconstituted newsprint or in other improved
paper products. The vast array of fluids having widely varying
specific gravities, viscosities, and other properties makes for
a great potential for studying unique applications of the Classi-
fier to many different kinds of solid wastes.
Since the operation of the prototype plant is in all cases inter-
mittent rather than continuous, analysis and re-evaluation may
be made at each step; and any of the above measures may be tested,
The more detailed flow diagrams of each step follow.
- 45 -
-------
BOWERMAN
CLASSIFIER
HEAVY
FRACTION
SUBSYSTEM
V
VARIOUS LIGHTER
CLASSES OF !
COMPONIfilTS
FCRROUS METALS
NON-FERROUS M6TALS
NOW - MET.flLS
MIXED
SOLID WASTE
PREPARATIONS
CLASStFICATtOKj
SEPARATION
SEGREGATgP
EWD PRODUCTS
PLATE f SOLID WASTE PILOT PLANT FLOW DIAGRAM
-------
STOKAGi
&1HS
(FOK fitttUNS)
HEAVY-FRACTION
PLANT FLOW SCHEMATIC
(Corapare Plate 1)
Scalper
A. Largest particles
B. Middle-sized par-
ticles
C. Fine particles
Grinder
D. Ground particles
Vibratory screen
E. No. 1 sized particles
F. No. 2 sized particles
G. No. 3 sized particles
H. Oversized particles
Shaping mill
I. Shaped particles
ready for Classifier
J. Shaped particles
needing resizing
Bowerman Classifier
K. High-density particles
L. Low-density particles
M. Particles from
traveling screen
Heavy-fraction Subsystem
N. Ferrous metals
0. Nonferrous metals
P. Heavy nonicetals
Q. Light nonmetals
2\ SOLID WASTE PILOT PLANT \ FLOOR PLAN
-------
(?)—(o)
/ Q'I '. V^' » \ « iJ £X
^'-^vi •',• r i ;* r i '1.1 r
'^1 k--.| ^JH
£J L_i_i_J_!
rera X
;^oppc,c_ j^
5TO«/5o5 &'N5
2.
3.
4.
30- or 40- gallon drums
General-purpose forklift
Feed hopper
Feed conveyor with drive
5. Trommel and drive
6. Storage bins for grinding
(See Step II)
9. Storage bins for sieving
(See Step III)
PLATE 3 SOLID WASTE PILOT PLANT
SCALPI'NG
-------
STEP I: SCALPING - PLATE 3 ABOVE
The mixed solid wastes are collected in the usual manner by a city or county agency
and stored at the pilot plant in covered 30- to 40-gallon drums (1). For certain
experimental purposes it may be desirable to preseparate such waste components as
steel cans, aluminum cans, glass, plastic,and paper by hand; but the bulk of the
pilot operation will preclude such action on the grounds that the input should sim-
ulate wastes as they would be received from municipal collecting vehicles.
A general-purpose forklift (2) conveys the drums to a hopper (3), from where they
are fed by conveyor (4) to a trommel (5). The trommel will probably consist of
two concentric drums rotating on an inclined axis. Material is fed into the inner
drum, which is pierced with holes large enough to allow all but the largest parti-
cles of waste to fall through to the outer drum. Smaller holes on the outer drum
allow particles below a certain size to pass to a chute, from where they are stored
in bins (9) for immediate passage to Step III, Sieving. These large- and middle-
sized particle segments, which reach only the inner or the outer drum, are stored
in bins (6) for grinding.
-------
l/l
o
2.
6.
7.
8.
9.
General-purpose forklift
Storage bins
Slat feed-conveyor with drive
Grinder and drive
-Storage bins
PLATE 4 SOLID WASTE PILOT PLANT
GRINDING
-------
STEP II: GRINDING - PLATE 4 ABOVE
The very largest particles received at the prototype plant (such as automobile
tires and the like, which have been identified by inspection and separated by
hand), as well as the middle- and large-sized-particle segments of the mixed
solid wastes already separated by the trommel (see Step I), are transported
from the storage bins (6) by the forklift (2) to the grinder-feed conveyor (7).
This slat conveyor feeds the grinder (8), which pulps, shreds, tears, breaks, and
reduces the materials to smaller size particles. The ground waste is added to
the storage bins (9), already containing the smallest particles separated by the
trommel, until a sufficient amount is accumulated for the sieving operation
(see Step III, below).
-------
REJECT HOPPER
2. General-purpose forklift
10. Feed hopper
11. Vibratory screen and drive
12. Receiving baskets
13. Storage bins
14. Reject hopper
PLATE 5 SOLID WASTE PILOT PLANT
SIEVING
-------
STEP III: SIEVING - PLATE 5 ABOVE
Output waste from Steps I and II must now be further classified according to size.
The most efficient device for accomplishing this is a vibratory screen, which will
not "blind," or close-up, with small, wetted particles of paper, garbage, etc. A
series of vibratory screens either on line or one above the other has been suggested
as a possible alternative to a single screen, for by then employing a graduated re-
duction in the size of the screen perforations a complete, single-run sizing could
be made. Smaller particles may proceed from the screen in their respective size
categories directly to the Bowerman Classifier (see Step V), while particles larger
than a certain size will require additional shaping (see Step IV). Experience will
in large measure determine the necessary capacity of this subsequent step.
In the diagram the forklift (2), delivers the ground waste to a feed hopper (10),
from which it is fed to the vibratory screen (11) with its successively smaller
perforations. Receiving baskets (12) at the end of each series of screen plates
accommodate the separated materials by size. These are periodically dumped into
separate storage bins (13) for retention until shaping or Bowerman Classifier opera-
tion. Particles too large either for shaping or for immediate Bowerman classifica-
tion are caught in a reject hopper (14) and recycled through the grinder (Step II,
above) . Experience may show that only one or two screen-perforation sizes are
necessary in this separation.
-------
KNURLED- SURFACE
V R°I-L CRUSHER
iX;». ~
STORAGE 9IKI.
15. Feed hopper
16. Knurled-surface rolls
17. Discharge chute
PLATE 6 SOLID WASTE PILOT PLANT
SHAPING
-------
STEP IV: SHAPING - PLATE 6 ABOVE
Sized material is fed from the top of the shaping mill into a feed hopper (15)
with a 4" x 4" safety grid and passes between two knurled-surface rolls (16)
under high compression. The rolls may be operated at a speed differential to
obtain grinding action. The gap between rolls is variable to permit experimenta-
tion at different loading rates and also to optimize size of the output material,
depending on experience in subsequent classifying. A discharge chute (17) delivers
the crushed, shaped material to a point above floor level, where it can be collected
for resieving or for Bowerman classification.
It may prove in operation that smaller particles segregated in Step III above will
need no further shaping and may proceed directly to the Bowerman Classifier; but
it is virtually certain that larger particles will require the more refined shaping
they will receive in this step than they will have already acquired in Steps I, II
or III. Experience must be gained for an understanding of the influence of the
rolls, particularly on metal particles. Since frangible materials such as glass
will be further broken and powdered by the heavy-pressure mill, it may prove desir-
able to re-sieve the material to separate some of the very fine particles.
-------
SLflT
COUVEYOR
CONNECTION
18. Feed hopper
19. Classifier tank (8' x 3' x 17«)
20. Slat feed conveyor with
variable-speed drive
21. Perforated baffles
22. Spray pump and drive
23. Distribution manifold
24. Removable collection baskets
25. Overhead monorail lift
26. Traveling screen with
variable-speed drive
27. Flat belt conveyor and chute
28. Mesh-cleaning spray and nozzles
29. Flanged connection of Classifier
tank (19) to traveling screen
tank (31--Plate 8)
PLATE 7 SOLID WASTE PILOT PLANT
BOWERMAN CLASSIFIER
-------
on
-o
STEP V: BOWERMAN CLASSIFYING - PLATE 7 ABOVE
In the pilot plant project, operation of the Classifier is to be stepwise rather
than continuous. Shaped solid wastes are dumped, one size-category at a time,
into a watertight feed hopper (18), where they may be pre-wetted with the same
fluid that is being used in the Classifier tank (19) • An inclined slat conveyor (20)
delivers the material to a carefully isolated discharge point just beyond the per-
forated upstream baffles (21). To ensure submergence, the particles may be further
wetted here by fluid in a line from the spray pump (22). The perforated baffles,
staggered with the distribution manifold (23), provide for uniform laminar flow of
the tank fluid, necessary for proper Classifier operation.
As the particles fall through the fluid, the current carries them along until they
collect in baskets (24) at the bottom of the tank. In general, heavy particles
(ferrous metals, brass, copper, etc.) drop into the upstream baskets, while the
lighter components (glass, aluminum, some plastics, etc.) are carried further down-
stream. It is unlikely, however, that the uniform separation of ihe baskets pro-
posed for the initial runs of the pilot plant will produce segregated batches of
material of nonoverlapping composition. Experience with the settling rates will
correct this deficiency. An overhead monorail lift (25) removes the baskets so
that the collected material can be evaluated.
The least dense components of the solid waste (especially floating particles of
cellulose and plastics) are carried out of the tank with the fluid and removed
by a traveling screen (26). This screen deposits them onto a flat belt conveyor,
from which they are chuted (27) to a collection point at floor level. A final de-
sign which will accomplish this latter suboperation while simultaneously wringing
fluid from the particles for return to the tank must await operational experience
with the Classifier. The shower pump (22) and spray nozzles (28) continuously keep
the mesh of the returning traveling screen open for drainage.
A separate schematic of a possible method of fluid flow control and instrumentation
of the Bowerman Classifier follows on Plate 8.
-------
en
CO
AIR VENT
CLASSIFIER TANK
DISTRIBUTION
HEADER
19. Classifier tank (81 x 3' x 17')
21. Perforated baffles
23. Distribution Manifold
30. High-capacity, low-head pump
and drive
31. Traveling-screen tank
32. 18-inch geared gate valve
33. 6-inch control valve
34. Flow meter
35. 4-inch level control makeup line
36. Air vent
37. Automatically controlled, variable-speed
traveling-screen drive
PLATE 8 SOLID WASTE PILOT PLANT HYDRAULIC SCHEMATIC
-------
STEP V: BOWERMAN CLASSIFICATION, CONTINUED: HYDRAULIC SCHEMATIC - PLATE s ABOVE
Plates 9a and 9b (following) demonstrate the nonlinear head-capacity and throttling
characteristics fo.r the low-head pump (30--Plate 8) and gate valve (32) arrangement,
such as might be employed to control the circulation of the fluid through the Classi-
fier tank (19), pastthe flanged connection (29--Plate 7), and through the traveling
screen tank (31), for piping back to the distribution manifold (23). The pump design
includes nonoverload characteristics, i.e., power cannot exceed the rated horsepower
of the driving unit.
Any flow less than the maximum-rated 12,000 gpm at 20-foot head would require less
power and might be attained by introducing in-cycle resistance in the form of a gate
valve (32). Because the large gate valve can give neither proportionate nor precise
control, a six-inch control valve (33) may be inserted in parallel with the main flow-
cycle. This valve provides a vernier control of flow for the system which the large
gate valve cannot accomplish by itself. Any required pumping rate from 12,000 to
1,200 gpm may thus not only be attained, but may also be reproduced by reference to
a flow meter (34) in the line. Streamlined flow may be improved by placing a second
partition of baffles (21) on the downstream end of the classifier tank, particularly
when the classifier is used for the finer separation of settled materials collected
in a prior run. These baffles must be removed when classifying prepared solid wastes
with a high percentage of floating paper and plastics.
A four-inch makeup line (35) is automatically controlled for filling the system and
maintaining level. An air vent (36) is placed at the high point of the piping to pre-
clude air entrainment and subsequent air binding of the pumping system. The speed of
the traveling-screen (37) is variable with head, i.e., as resistance builds up due to
screen mesh becoming clogged, the increase in head on the upstream side (of screen)
speeds up the screen travel and cleaning operation.
A typical start-up procedure follows:
1) Fill system with makeup valve opened.
2) Throttle gate valve to 1/4- to 1/2-open position.
3) Start pump at low rate of flow and evacuate all air from system.
4) Check flow rate on meter and gradually open large gate valve until
approximate desired flow is attained.
5) Throttle six-inch vernier control to attain precise flow rate desired;
the automatic makeup valve will now maintain the system in equilibrium.
6) Start spray pump to keep mesh of travelling screen open for free drainage.
7) Start conveyor feeding wastes to classifier tank.
8) Start reject belt conveyor on screen.
-------
ki 3:
70 35
60 30
50 25
40 20
30 15
10
0
2000
4OOO
6000
n,0!"0 I2/';')0
FLOW PATE
TYPICAL CENTRIFUGAL PUMP
HEAD-CAPACITY CURVE
PLATE9-A SOLID WASTE PILOT PLANT PUMP CAPACITY CURVES
-------
PLATE 9-B<
metal seated valves (round port)
FLOW CHART-Valve Wide Open
1,000.000
•00.000
600.000
.. .2 A .4.5.6 .8 1 2 3 4 56 8 10
PRESSURE DROP (PSD
*Source: DeZurik Corporation, Sartell,
Minn. Bulletin 30 .00-1, "Series
L, Knife Gate Valves,"
1971, page 4.
"February,
Cv VALUES
(Flow in GPM of water
at 1 psi pressure drop)
HEADLOSS-
(Feet of Pipe)
AREA OF
OPENING
2"
3"
4»
6*
8"
10*
12"
14"
16"
18"
20"
24"
30*
36"
240
565
1040
2440
4460
6250
9400
12500
16500
21400
27000
39700
62000
93000
2.5
3.6
4.4
6.8
8.7
14.0
15.0
16.0
18.0
20.0
22.0
26.0
34.0
41.0
3.14
7.07
12.60
28.80
50.30
69.00
102.0
133.0
174.0
227.0
280.0
411.0
619.0
911.0
•Pressure drop in equivalent length (feet) of standard
weight steel pipe.
Sizing based on discharge into conduit rather than atmo-
sphere.
THROTTLING CHARACTERISTIC
j J « 5 10 IS 10 SO 40 M
FIOWTORU VALUE - » OF MAXIMUM
100
61
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FEED HOPPER
38. Feed hopper
39. 20-inch magnetic drum
separator
40. Variable-speed drive
41. Ferrous-metals container
42. Scraper blade
43. 24-inch flat belt 48.
conveyor
44. Variable-speed drive 49.
45. Leveling curtain 50.
46. Metal-detection coil 51.
47. Adjustable plow 52.
Plow actuator (on signal
from coil, 46
Nonferrous metals container
High-pressure air nozzle
"Light nonmetallics" container
"Heavy nonmetallics" container
PLATE io SOLID WASTE PILOT PLANT ^-IEAVY FRACTION SUB SYSTEM
-------
STEP VI: HEAVY-FRACTION CLASSIFICATION - PLATE 10 ABOVE
The "heavy" (i.e., most dense) fraction of the material segregated in the Bower-
man Classifier is now given additional refinement. A feed hopper (38) controls
the delivery of the input material to a magnetic drum separator (39). A station-
ary permanent magnet holds ferrous particles onto a concentric rotating drum,
powered by a variable-speed drive (40), until the particles move out of the mag-
netic field and are scraped off the drum into a container (41) by a scraper blade
(42).i Nonmagnetic particles drop over the drum without clinging to it and onto
a belt conveyor (43), also provided with variable-speed drive (44). This material
is flattened and spread as it moves along the belt by an adjustable leveling cur-
tain (45), prior to passing a metal-detection coil (46).
The coil is "tuned" to detect fragments of nonferrous metal larger than a certain
size, which are plowed (47) on signal (48) off the conveyor belt and into a con-
tainer (49).
The smaller particles of nonferrous metals remain on the belt, along with other
residues of plastics, glass, etc., and travel to the discharge point of the con-
veyor. As this material drops from the belt, it is met by a high-velocity jet
of air (50), which is adjusted to blow less dense particles aside into a "light
nonmetallics" container (51), while allowing the denser particles to fall through
into a "heavy nonmetallics" container (52).
-------
POSTSCRIPT
The proceeding schematic account of the proposed prototype plant
has been included for the clarity of this report. It is based on
preliminary specifications developed by the Zurn Environmental
Engineers and the ERIEZ Manufacturing Company prior to the actual
drafting of the report. Yet while they are similar to these speci-
fications, the schematics do not pretend to conform in every detail
several discrepancies have already been noted on pages 40-41. Such
present recognition of alternative methods of dealing with various
technical problems will undoubtedly serve to speed implementation,
should the proposed project be given approval. It reflects some
of the intensive critical evaluations in each area of the project,
which have continued since the specifications were released. These
original preliminary specifications are included for completeness
below in Sections VI and VII.
- 64 -
-------
SECTION VI: BOWERMAN CLASSIFIER
(As ORIGINALLY DEVELOPED BY THE ZURN ENVIRONMENTAL ENGINEERS)
A
-------
-------
This section contains preliminary specifications developed by
the Zurn Environmental Engineers of Zurn Industries, Inc., for
the assembly of the grinding, sieving, shaping, and Bowerman
Classifying units of the proposed pilot plant. As with the sche-
matic diagrams of Section V, these specifications should in no way
be considered^final; indeed, variations between these designs and
several ideas incorporated into the schematics have already been
noted (see pages 40-41). In the drawings prepared by the Zurn
Environmental Engineers the components mentioned above are arranged
on two moveable skids, the "Stage One, Grinder" Skid (Plate 11)
and the "Stage Two, Sorter" Skid (Plate 12). The reader is encour-
aged to refer to these plates as the narrative proceeds.
- 65 -
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PART I; General
The Stage One, Grinder Skid consists of grinder, sieve, travel-
ing screen, spray pump, tank, structural steel base, rolls, and
miscellaneous electrical and mechanical support. The Stage Two,
Sorter Skid consists of pump, drive, conveyor, baskets, accessor-
ies, piping, tank, skid, and electrical and mechanical support to
the operation. As shown in the two plan views, the right end of
the Bowerman Classifier in Stage II will be mated to the left
end of the Stage I assembly by bolting the two gasketed connec-
tions together to make one integral hydraulic unit. A similar
gasketed and bolted connection will be made between the twenty-
inch pipe, connected to the valve on the Stage I platform, and
the pump on the Stage II platform. The in-line connection of
the two stages, rather than an L-shaped connection, was decided
upon to maintain as uniform a flow as possible with velocity
streamlines remaining nearly parallel up to the traveling water
screen on the Stage I platform.
To place the assembled unit in service, the tank will be filled
with an appropriate fluid to a depth of six feet, maintaining
a free-board of two feet to the top of the tank. Inasmuch as
the maximum impediment to fluid flow would occur at the upstream
face of the water screen, the excessive clogging of that water
screen with materials such as paper or plastic would simply cause
the suction line to the pump to draw down the water level behind
the screen, perhaps to a point of shutoff. Nevertheless, there
- 66 -
-------
is sufficient surge capacity in the two feet of free-board in
the Classifier (Stage II) to prevent overflow of fluid even if
the pump for the traveling water screen were slowed down to a
point of shutoff. When filled with water, kerosene, or tricholor-
ethylene, the system requires a 200 KVA external power supply to
fulfill complete operating requirements specified herein.
The work under these specifications shall include the furnish-
ing of all materials, labor, and equipment to construct and
test the two skid-mounted units capable of being connected in
the field, each consisting of mechanical, structural, and elec-
trical equipment. This equipment is described in the following.
PART 2: Mechanical
2-01. Stage One, Grinder. Skid shall consist of one skid
on which shall be mounted the grinder, the sieve, the traveling
screen, spray pump, tank rolls, necessary access, power, lights,
mechanical, and electrical support to the operation.
a. Grinder. An Eidal International Corporation solid
waste reduction Model 75 Mini-Mill, or equivalent, shall be installed
on the skid. Mini-Mill shall be complete in operating order with
75-horsepower, 460-volt, 3-phase, 60-Hertz motor for 460-RPM
operation.
b. Sieve. The Contractor shall provide one Hewitt-
Robins Model 16-30 contractor's sieve, or equivalent, complete
with stainless steel perforated screens. The Hewitt-Robins sieve
- 67 -
-------
shall be modified to readily receive one of four 20-gauge stain-
less steel perforated screens constructed as follows:
1. Screen Number 1 shall be provided with
•
1-1/4-inch holes on 2-inch centers staggered throughout the
active area of the screen.
2. Screen Number 2 shall be perforated with
5/8-inch holes on 1-inch centers staggered throughout the
active area of the screen.
3. Screen Number 3 shall be constructed with
3/16-inch holes on 3/4-inch centers staggered throughout the
active area of the screen.
4. Screen Number 4 shall be perforated with
3/32-inch holes on 1/2-inch centers staggered throughout the
active area of the screen.
Sieve shall be mounted on the skid and connected
for operation. Chutes shall be provided as shown on the plans.
c. Traveling Screen. The Contractor shall provde
a 6-feet-wide by 12-feet-high shaft traveling water screen such
as that manufactured by Rex Chainbelt, Inc., complete with all
operating accessories, and a 1-1/2 horsepower variable-speed drive
for 0.2 to 2 feet-per-minute screen travel. The 32-mesh screen
and chain assembly shall be corrosion resistant;, a spare set of
8-mesh screen trays shall be provided for replacement. Buna N or
wood seals shall be installed to provide 1/32 inch clearance in
the fluid stream.
- 68 -
-------
Spray header shall have a throttling valve. The trash collecting
trough shall be integral with main assembly. Pressure grease lub-
rication shall be provided to all points, from the variable drive
adjustment position at tank top. Fluid drive and shear pins shall
be used to protect the equipment. Screen shall operate from 6 feet
normal depth to 7-1/2 feet flow depth but shall be capable of
operating with a 5 feet intake water head.
>d. Spray Pump. The Contractor shall provide one all
iron worthington 1-1/2-CNF-74 open impeller, end suction Monobloc
centrifugal traveling screen spray pump, or equivalent, for 150
gpm, 220 feet total dynamic head operation. Pump shall be equipped
with 20 horsepower motor and protected by a suction strainer.
e. Tank. The 6 feet by 11 feet tank and traveling
water screen enclosure on the Stage One, Grinder skid shall be
constructed per these specifications.
^- Rolls. The Contractor shall provide an adjust-
able variable speed rolling mill consisting of two 6-inch diam-
eter by 2 feet long Hastelloy knurled surface rolls, or equiva-
lent, with a nontouching adjustable gap of 3/16 inch to 3 inches
positioned by a 2,000 pound spring compression and protected by
a shear pin arrangement. Feed shall be downward and discharge
shall be outward. Feed hopper shall have 4 inch by 4 inch safety
grid and discharge at least 2 feet above base. Variable 20:1,
10 horsepower electric drives shall be provided to obtain 0.75
to 15 feet per second peripheral speed on one roll and 0.5 to 10
.feet per second peripheral speed on the other roll.
- 69 -
-------
g. Miscellaneous. Butterfly valve shall be 20 inch
water type tight shutoff. The necessary metering, pressure guages,
and temperature guages shall be provided-.
2-02. Stage Two, Sorter shall consist of one skid on which
shall be mounted the pump, drive, conveyor, accessories, piping,
tank, motor control center, and electrical and mechanical support
to the operation.
"a. Pump. The Contractor shall provide one 20-inch
horizontal, single-stage, axial flow Cascade propeller pump of
all iron, bronze fitted construction with stainless type 416
pump shaft. Pump performance shall be 12,000 gpm water at 20
feet total dynamic head and 80 percent efficiency; pump shall be
capable of 1,200 gpm at a lesser head and efficiency (see Plates
9-A and 9-B). Packing shall be compatible with the various fluids
specified.
b. Pump Drive. The Contractor shall provide one
100-horsepower 440-volt, 3-phase, 60-Hertz motor drive connected
to a 10:1 manually adjustable variable speed drive with all ac-
cessories complete and operating on a continuous baseplate with
the pump above to provide 1,200 to 12,000 gpm pump capacity.
c. Conveyor. A portable inclined conveyor approxi-
mately 20 feet long and 30 inches wide shall be provided with
the variable speed motor, alowing belt speeds of 50 to 20 feet
i
per minute. Belt shall be of natural rubber with 1-1/2 inch
flights on 12 inch centers. Feed shall be through a 25 cubic
feet open water tight hopper at grade. Motor connection shall be
through a Grouse Hinds waterproof connector to skid. Conveyor
shall have sufficient rigidity to be relocated by crane.
" 70 '
-------
d. Accessories.
1. A 1/2 ton Yale and Towne chain hoist, or equivalent,
with 20 feet of chain and hook shall be mounted on monorail
above tank.
2. The necessary metering, pressure guages,
and temperature guages shall be provided.
3. The Contractor shall provide four (4)
2 feet 9 inch by 6 foot high baffle plates of ;/4 inch 316
stainless steel with 3 inch diameter holes in staggered rows
to provide at least 50 percent open area. Offset row pattern
is to be reversed on two of the baffle plates.
e. Piping. Piping shall be ASTM A-120 black
welded pipe, Schedule 40 for 5 inch diameter and smaller Schedule
20 for 6 inch diameter and larger. All welded construction with
ASA 125 pound flange connections is permitted for 3 inch diameter
and larger at pump, valves, etc. If a piping assembly exceeds
20 feet in length, a flanged union shall be provided. Screwed
fittings with appropriate unions shall be used for smaller sizes.
Part 5: Structural Steel
a. The work covered by -this section includes the
furnishing and installation of the tank, skids, machinery support,
access platforms and ladders, inspection windows, and miscellaneous
metal.
b. Tank. The structural steel water tank shall con-
sist of two sections each constructed of 1/4 inch steel plate rein-
forced with 4-inch by 4-inch I-beam columns which are extended to
become the overhead chain hoist support. The Stage Two, Sorter
- 71 -
-------
skid tank is 3 feet wide by 8 feet high by 17 feet long. The
Stage One, Grinder skid tank is 3 to 6 feet wide by 8 feet high by
11 feet long. The 4-inch by 4-inch I-be'am columns become tank
reinforcing and traveling screen support.
c. Skid. The Contractor shall provide two rigid
structural steel bases for support of the tank and equipment.
Appropriate dimensions are 6 feet by 28 feet long and 6 feet by
17 feet long. Necessary eye bolts for hoisting and slots for
forklift truck lifting shall be provided. Nonskid floor plates
shall cover entire machinery area.
d. Machinery Bases. The Contractor shall provide
machinery bases as required for rigid mounting of machinery.
Stowage shall be provided for rail or truck transportation.
e. Inspection Windows^. Four inspection windows
approximately 12 inches by 12 inches shall be provided on the side
of the tank opposite the lights.
f- Walkway. A 24-inch walkway shall be provided
along the full length of the tank and both sides of traveling
screen. Handrails shall be provided as required for safety.
8- Baskets. The Contractor shall provide five
baskets approximately 33 inches by 33 inches by 5 inches deep.
Baskets are to be constructed of 3/8 inch rod and rigid to a
loading to 20 pounds per square foot of a 32 mesh on bottom
of the basket. Sides shall be solid; baskets shall be provided
with stabilized handle lift.
- 72 -
-------
Part 4: Electrical
4:01 General Requir'eirients. The work covered by this sec-
tion consists of furnishing all labor, materials, and equipment
required to install a complete operable electrical system on
each of the skids from a 440-volt, 3-phase, 60-Hertz, external
source. System shall include 3-phase service pole, transformer,
electric motors, starters, lighting panel, and power panel on the
Stage Two, Sorter skid,with lighting and power system for com-
plete operation.
a. Panel. The NEMA IV, or equivalent, control panel
shall contain motor starters, transformer, lighting panel, meter-
ing station, main disconnect with voltmeter and ammeter, instru-
ments and controls. All integral motor starters shall have a
load ammeter. All motor starters shall have "off" and "run"
lights. Circuit breakers shall be of the molded case type.
b- Motors. Electric motors shall be the squirrel
cage induction type of weatherproof construction with weather-
proof start-stop push button stations at each motor location.
Motors 1/3-horsepower and above shall be designed for 440-volt,
3-phase, 60-Hertz operation. Smaller motors shall be the 120-volt,
single-phase, type.
c. Lighting. Twenty-five foot candles of overhead
lighting shall be provided at each work station. All lighting
fixtures shall be sealed, dust-tight construction.
d. Outlets. One 440-volt, 3-phase, 60-Hertz, 60-
ampere welding receptacle with cover shall be provided at the
motor control center and one duplex 110-volt, single-receptacle
with cover shall be provided for each skid.
- 73 -
-------
e. Connectors. Power connections between skids
and between skid and portable equipment shall be of weather-
proof lock tight connectors with three feet of cable to each
half.
f- Conduit. All conduit shall be PVC coated metal.
•>•"
Part 5: Painting
All wetted and splash areas shall be unpainted carbon steel
except where otherwise specified. Remaining exterior surfaces
shall be sandblasted to near-white condition, primed with Koppers
Zinodic-0 and finished with Koppers Dynacol 35 HB.
Part 6: Test and Operations
System shall be field assembled at the manufacturer's shop,
filled with water and all operable machinery tested with one ton
of sample material.
- 74 -
-------
Part 4: Electrical
4:01 General Requirements. The work covered by this sec-
tion consists of furnishing all labor, materials, and equipment
required to install a complete operable electrical system on
each of the skids from a 440-volt, 3-phase, 60-Hertz, external
source. System shall include 3-phase service pole, transformer,
electric motors, starters, lighting panel, and power panel on the
Stage Two, Sorter skid,with lighting and power system for com-
plete operation.
a. Panel. The NEMA IV, or equivalent, control panel
shall contain motor starters, transformer, lighting panel, meter-
ing station, main disconnect with voltmeter and ammeter, instru-
ments and controls. All integral motor starters shall have a
load ammeter. All motor starters shall have "off" and "run"
lights. Circuit breakers shall be of the molded case type.
b. Motors. Electric motors shall be the squirrel
cage induction type of weatherproof construction with weather-
proof start-stop push button stations at each motor location.
Motors 1/3-horsepower and above shall be designed for 440-volt,
3-phase, 60-Hertz operation. Smaller motors shall be the 120-volt,
single-phase, type.
c. Lighting. Twenty-five foot candles of overhead
lighting shall be provided at each work station. All lighting
fixtures shall be sealed, dust-tight construction.
d. Outlets. One 440-volt, 3-phase, 60-Hertz, 60-
ampere welding receptacle with cover shall be provided at the
motor control center and one duplex 110-volt, single-receptacle
with cover shall be provided for each skid.
- 73 -
-------
e. Connectors. Power connections between skids
and between skid and portable equipment shall be of weather-
proof lock tight connectors with three feet of cable to each
half.
f- Conduit. All conduit shall be PVC coated metal.
y *t
Part 5; Painting
All wetted and splash areas shall be unpainted carbon steel
except where otherwise specified. Remaining exterior surfaces
shall be sandblasted to near-white condition, primed with Koppers
Zinodic-0 and finished with Koppers Dynacol 35 HB.
Part 6; Test and Operations
System shall be field assembled at the manufacturer's shop,
filled with water and all operable machinery tested with one ton
of sample material.
- 74 -
-------
Part 4: Electrical
4:01 General Re qu 1 rentents . The work covered by this sec-
tion consists of furnishing all labor, materials, and equipment
required to install a complete operable electrical system on
each of the skids from a 440-volt, 3-phase, 60-Hertz, external
source. System shall include 3-phase service pole, transformer,
electric motors, starters, lighting panel, and power panel on the
Stage Two, Sorter skid,with lighting and power system for com-
plete operation.
a. Panel. The NEMA IV, or equivalent, control panel
shall contain motor starters, transformer, lighting panel, meter-
ing station, main disconnect with voltmeter and ammeter, instru-
ments and controls. All integral motor starters shall have a
load ammeter. All motor starters shall have "off" and "run"
lights. Circuit breakers shall be of the molded case type.
b. Motors. Electric motors shall be the squirrel
cage induction type of weatherproof construction with weather-
proof start-stop push button stations at each motor location.
Motors 1/3-horsepower and above shall be designed for 440-volt,
3-phase, 60-Hertz operation. Smaller motors shall be the 120-volt,
single-phase, type.
c. Lighting. Twenty-five foot candles of overhead
lighting shall be provided at each work station. All lighting
fixtures shall be sealed, dust-tight construction.
d- Outlets. One 440-volt, 3-phase, 60-Hertz, 60-
ampere welding receptacle with cover shall be provided at the
motor control center and one duplex 110-volt, single-receptacle
with cover shall be provided for each skid.
- 73 -
-------
e. Connectors. Power connections between skids
and between skid and portable equipment shall be of weather-
proof lock tight connectors with three feet of cable to each
half.
f. Conduit. All conduit shall be PVC coated metal.
"j***
'- .' f
Part 5; Painting
All wetted and splash areas shall be unpainted carbon steel
except where otherwise specified. Remaining exterior surfaces
shall be sandblasted to near-white condition, primed with Koppers
Zinodic-0 and finished with Koppers Dynacol 35 HB.
Part 6: Test and Operations
System shall be field assembled at the manufacturer's shop,
filled with water and all operable machinery tested with one ton
of sample material.
- 74 -
-------
Part 4: Electrical
4:01 General Requirements. The work covered by this sec-
tion consists of furnishing all labor, materials, and equipment
required to install a complete operable electrical system on
each of the skids from a 440-volt, 3-phase, 60-Hertz, external
source. System shall include 3-phase service pole, transformer,
electric motors, starters, lighting panel, and power panel on the
Stage Two, Sorter skid,with lighting and power system for com-
plete operation.
a. Panel. The NEMA IV, or equivalent, control panel
shall contain motor starters, transformer, lighting panel, meter-
ing station, main disconnect with voltmeter and ammeter, instru-
ments and controls. All integral motor starters shall have a
load ammeter. All motor starters shall have "off" and "run"
lights. Circuit breakers shall be of the molded case type.
b. Motors. Electric motors shall be the squirrel
cage induction type of weatherproof construction with weather-
proof start-stop push button stations at each motor location.
Motors 1/3-horsepower and above shall be designed for 440-volt,
3-phase, 60-Hertz operation. Smaller motors shall be the 120-volt,
single-phase, type.
c. Lighting. Twenty-five foot candles of overhead
lighting shall be provided at each work station. All lighting
fixtures shall be sealed, dust-tight construction.
d. Outlets. One 440-volt, 3-phase, 60-Hertz, 60-
ampere welding receptacle with cover shall be provided at the
motor control center and one duplex 110-volt, single-receptacle
with cover shall be provided for each skid.
- 73 -
-------
e. Connectors. Power connections between skids
and between skid and portable equipment shall be of weather-
proof lock tight connectors with three feet of cable to each
half.
f. Conduit. All conduit shall be PVC coated metal.
*v
•..•e
Part 5; Painting
All wetted and splash areas shall be unpainted carbon steel
except where otherwise specified. Remaining exterior surfaces
shall be sandblasted to near-white condition, primed with Koppers
Zinodic-0 and finished with Koppers Dynacol 35 HB.
Part 6: Test and Operations
System shall be field assembled at the manufacturer's shop,
filled with water and all operable machinery tested with one ton
of sample material.
- 74 -
-------
-J
t/J
STMt I e*»ID fit
BOWERMAN CLASSIFIER
Gft£AT LAKE3
SCl£l>iCC <*C,
•Of" tUtftenfitl t* &«W fff JMC
Plate 11
-------
•» COMHCCT/OM TO
STtCCJ
EMO
ELEVATION
BOWERMAN CLASSIFIER.
G/tetr L*iffs RcsttitCH
lUXH
Plate 12
r
-------
SECTION VII: HEAVY-FRACTION SUBSYSTEM
(As ORIGINALLY DEVELOPED BY THE ERIEZ MANUFACTURING COMPANY)
-------
-------
This section provides the detailed specifications and drawings
of the heavy-fraction subsystem produced by the ERIEZ Manufactur-
ing Company. The overall system is represented pictorially by
Plate 13 (page 79) and dimensionally by Plate 14 (page 80).
The system is designed to give most efficient separation on dry,
shredded particles up to three inches in diameter into magnetics,
non-magnetic metallics, and two different-density groups of
nonmetallics. Material up to five inches in diameter will, how-
ever, be permitted to pass.
In order to achieve this separation the input material must be
fed uniformly, without surges, into the entry point of the system,
The system is designed to process the particles at a rate of one-
half ton per hour. Although all separate functions are tied to-
gether into one continuous feed belt, each is variable in speed,
wipers and deflectors are variable in rigidity, and the quantity
of material run can be varied. Thus a true pilot study of the
system can be made.
GENERAL SPECIFICATIONS
CONTAINERS - must be light weight and portable. Material is
reinforced plastic. Quantities of each size re-
quired are given below:
QUANTITY SIZE
2 24" sq. x 24" high
1 16" sq. x 24" high
2 16" sq. x 20" high
- 77 -
-------
UTILITIES - approximately 4 cubic feet per minute of 75 to 150
psi air is required. Electric power should be 220/
440 volts, AC, 60 cycle.
•
Specifications and descriptions as well as operating variables for
the separate functions of the system follow.
An alternate device for the separation of nonmagnetic metallics
from nonmetallics has been proposed, and the drawings and specifi-
cations are included as Appendix C.
- 78 -
-------
PICTORIAL LAYOUT
REFUSE SORTING SYSTEM
Htl'tffO ro*
GRCAT LtxCS KCSfltltCH IHSnTUTC
ERIEZ MAGNETICS
HefoaM*rc*s
Emu UAHijf/icrunme Co.
Plate 13
r
-------
00
o
i
fc^=i
\
ntfiaoa
&
~-1.-
SFT
THIS Sftcf mo ccrminea
tOJIO
L/l
-' /9V. '-
{HTAO &JLLTY-
•r~
frt
OVERALL APftANOEUEKT
REFUSE SORTING SYSTEM
f*t***e0 FQ*
SRCAT LAKES frcse*nCH INSTITUTE
ERIEZ MAGNETICS
CO.
Plate 14
-------
JL
>C*MM
A
(
K >
5
— — 4
/
\ '
n
j
K I
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VCNfjf
k
1
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/ROM
1
t
n
to
33*i
ffOK
,
.
KX*. HCI6MJ
IHOH •cota»n
(SHCXVM fOa KEFEfXNCe OULY)
.ERiEZ.:jaDtA*.2dJFncE.
MAGNETIC' DRUM W SPECIAL. HOUSING
SUf>l=>OF*r BASE TO
Plate 15
SPECIAL MAGNETIC DRUM
REFUSE SORTING SYSTEM
GREAT LAKE RESEARCH INSTITUTE
ERIE2 MAGNETICS
HEADQUARTERS
ERIEZ MANUFACTURING Co.
r
-------
SPECIAL MAGNETIC DRUM - PLATE is ABOVE ,
^
The unit is self standing and driven independently of any other area of the system.
Therefore, it can be moved away from the system so that other methods of feed to
the belt conveyor can be studied and so that other methods of magnetic separation
can be evaluated. (A suspended self-cleaning magnet over the conveyor is a method
of magnetic separation worth consideration,although its merit will depend on space
limitations, etc.)
The magnetic drum in housing has been selected as most applicable to this system
considering all variables. Permanent magnetic material is Erium 25, stable between
zero and 150 degrees F. Drive speed is variable and allows drum rotation speeds
00 between 20 and 60 rpm. (Normal fixed speed of magnetic drums of this size is 35 rpm.)
tsj
Nonmagnetics will be discharged directly onto the sorting conveyor belt and magnetics
into a portable container set under the iron discharge opening.
A feed regulation deflector is provided to prevent material fed onto the drum from
bouncing out of the magnetic influence field of the drum. The regulation deflector
is not to meter material out of the feed hopper, as the material to be run will not
feed in this manner. It must be kept moving or it will pack.
Adequate access panels are built into the drum housing to allow internal adjustments
on deflectors and to visibly examine flow through the drum housing. Construction
material for the drum and housing is further described in ERIEZ Bulletin SB-340..
-------
PLAN VIEW OF SCftrtNG OONVEVOF* BETWEEN
t METAL DETECTOR
+ 4-
W- +
« Of ILL
-notes /A/ «>vwr>o
-------
SIDE DISCHARGE BAFFLE - PLATE 16 ABOVE
When multiple stage magnetic separation is to be studied and evaluated, the side
discharge baffle will be mounted as shown in the area between the discharge of
the magnetic drum and the metal detector coil. In this area of the conveyor it
will be necessary to remove short lengths of skirts on both sides of the conveyor.
Material deflected by the baffle will discharge into a portable container.
-------
I
I*
* »
*— o
- CJ
r - •• « ^J
/
00
SLIT,
FLEXIBLE
BL»ST
DETECTOR
~\
Ji^JLll
^ y
r
Jf, uiM.n MIM . ..•»..» . -r^
Plate 17
LEVELER
REFUSE SORTING SYSTEM
GREAT LAKES RESEARCH INSTITUTE
ER1EZ MAGNETICS
HEADQUARTERS
MANUFACTURING Co,
-------
LEVELER - PLATE 17 ABOVE
^i
While the magnetic drum will spread out the material on the sorting belt, some
items may bounce and lie on others, particularly when either the drum or conveyor
belt is operating at or near its highest speeds. For best operations from the
metal detector and rejection station the material reaching this area should be
as level and spread out as possible. Experimentation and adjustment with the
leveling curtain and air blast will perfect this function. Items are described •
on the plates. The curtain material and its degree of stiffness can be final-
ized only after actually running the system. It is advisable to furnish several
curtains of different length and stiffness with the initial unit.
Structural items and piping are steel and should be mounted so that they can be
easily moved (or removed, if the nature of the operation does not warrant them).
Air for the leveler system is 75 to 150 psi and is from the source also supplying
the plow cylinder further down the belt.
-------
(1src. -«r
(A StV AT JZO F**t)
Plate 18
METAL DETECTOR SEARCH COIL
LOCATION
REFUSE SORTING SYSTEM
METAL. O£TfC7Oft SEMTCH
GREAT LAKES RESEARCH INSTITUTE
AOjACEMT TO OOTTOM & SLiOEK PLAT&-.
ERIEZ MAGNETICS
HEADQUARTERS
ERIEZ MANUFACTURING Co.
-------
METAL DETECTOR COIL - PLATE is ABOVE
Detection and rejection arrangements of the type necessary for this sorting system
always require on-the-job initial adjusting and tuning. The actual mounting posi-
tion of the coil can be fixed, but because the conveyor belt will have a variable'
speed, it will be necessary to reset the detector coil with belt speed changes.
A control box is to be furnished with the coil and it contains the necessary adjust-
ments to tune the detector coil strength and to set the time lag of the signal to
the plow that follows the coil.
-------
00
<£>
aer/in. x. '_
FLANGED 'OJO.
ROLLER
POtLO*veF9
CO, /S\
' THICK f?EI*JF&?CEC>
27E£Z
SUPPORT
- SfESi. .
' THICK M/OOO.
Plate 19
PLOW FOR METALLICS REJECTION
REFUSE SORTING SYSTEM
PREPARED fO*
GREAT LAKES RESEARCH INSTITUTE
ERIEZ MAGNETICS
HEADQUARTERS
ERIEZ MANUFACTURING Co.
r
-------
PLOW FOR METALLIC REJECTION - PLATE 19 ABOVE
*
Discharge of metallics will be over both sides of the belt. The plow (upon signal
from the detector coil control box) will move across the belt and remain there
until it receives another signal to return. Both directions of plow travel are
rejection strokes, so that the metallics container under this section of the con-
veyor must be wide enough to receive both these discharges.
If the plow receives a second signal during its travel across the belt, it will
immediately return to ensure that no metallics get past this position.
Maximum plow width is 18 inches. The speed of the belt conveyor will determine wheth-
er a narrower plow can be used. Assuming a 60 fpm (1 fps) belt velocity and a
time of one-third second for the plow to travel across the belt, a 12-inch-wide
plow will suffice. Only the minimum width plow necessary to ensure that no metallics
can get by the rejection station should be used. In this way, the discharge of
nonmetallics along with metallics will be minimized.
Plate 19 above lists the main components of the plow assembly.
The air cylinder is to be furnished with all necessary valves, filters, etc., to
make only a connection to the 75- to 150-psi air source necessary.
-------
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ALL. trsMS
7ff/S LCH6TH MUST
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COJVCVOI* 3t£>& FfUUS,
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Plate 20
SORTING CONVEYOR
REFUSE SORTING SYSTEM
GREAT LAKES RESEARCH INSTITUTE
ER1EZ MAGNETICS
HEADQ.UAFt7E.RS
MANUFACTURING Co.
-------
SORTING CONVEYOR - PLATE 20 ABOVE
Material burden is minimal and can be ignored in conveyor construction design.
Most important to successful operation of the system is a conveyor construction
which allows easy and quick adjustments to the various allied assemblies.
The belt is 14 inches wide and has a smooth surface. A teflon-coated belt is
recommended. The belt should be endless or laced with nonmetallic lacing.
The skirt assemblies should be short (approximately two feet) sections and ar-
ranged so that no material being conveyed can snag and hang up at the joints of
skirt sections.
Overall construction will be per Plate 20,but all drawings covering this system
should be studied so the conveyor manufacturer can fully understand what is ex-
pected.
The head pulley is eight inches in diameter and should be rubber lagged.
motor is 220/440 volts, AC, 60 cycle.
The drive
-------
f
UfT-
, DEFLECTOR HOGO.
33
L
I]
uttn'i \*it
Plate 21
AIR CLASSIFIER.
REFUSE SORTING SYSTEM
GREAT LAKES RESEARCH INSTITUTE
ERIEZ MAGNETICS
HEADQUARTERS
MANUFACTURING Co.
-------
AIR CLASSIFIER - PLATE 21 ABOVE
This area, like the other sorting functions of the system, will require "tuning"
to the conveyor speed and to material being handled. The air blast header pipe
should be mounted so that it can be moved horizontally and vertically and tipped.
The hopper (container) positions will require some changing to find their most
efficient separation location.
Air for the classifier is 75 to 150 psi and is from the source supplying the plow
cylinder.
-------
SECTION VIII: COST ANALYSIS
A-
-------
-------
Total projected costs for the three-year funded period of the
solid waste prototype project herein described are $688,600.
•
Of this amount, $172,070 is projected as funds to come from the
resources of the applicant. The remaining projected $516,530
are funds which would be requested from the Environmental Pro-
tection Agency. Cash flow has been determined as follows:
First • Second Third
Total Year Year Year
Amount from Applicant's source $172,070 $114,870 $ 30,050 $ 27,150
Amount requested from EPA 516,530 344,820 90,170 81,540
TOTAL $688,600 $459,690 $120,220 $108,690
The First-Year projected costs include approximately $250,000
start-up and construction costs.
- 95 -
-------
-------
SECTION IX: REFERENCES
With the exception of numbers 3**, 38, and k],
all references have been verified and restyled by
the Office of Solid Waste Managment Programs,
U.S. Environmental Protection Agency,
A
-------
1. Boettcher, R. A. Air classification for reclamation of solid
wastes. Compost Science, ll(6):22-29, Nov. -Dec. 1970.
2. Black Clawson Company. Unpublished data, Dec. 1969.
3. Personal communication. F. R. Bowerman.
A. [HjS.- Bureau of Mines - Mining technology review]:
Taggart, A. F. Elements of ore dressing. New York, John
Wiley & Sons, Inc., 1951. 595 p.
Taggart, A. F. Handhook of mineral dressing; ores and
industrial minerals. New York, John Wiley & Sons, Inc.,
1945.
Peele, R. , and J. A. Church, eds . Mining engineers'
handbook. 3d ed. New York, John Wiley & Sons, Inc., 1941.
2 v.
Camp, T. R. Sedimentation and the design of settling tanks
Transactions of the American Society of Civil Engineers,
111:895-936, 1946.
Cservenyak, F. J., and C. B. Kenahan. Bureau of Mines
research and accomplishments in utilization of solid
wastes. U.S. Bureau of Mines Information Circular No.
8460. Washington, U.S. Department of the Interior, 1970.
29 p.
Gulp, R. L. Wastewater reclamation at South Tahoe Public
Utilities District. Journal. American Water Works
Association. 60 (1) : 84-102 , Jan. 1968.
Drobny, N. t. , H. E. Hull, and R. F. Testin. Recovery
and utilization of municipal solid waste; a summary of
available cost and performance characteristics of unit
processes and systems. Public Health Service Publication
No. 1908. Washington, U.S. Government Printing Office,
1971. 118 p.
Einstein, H. A. The bed-load function for sediment
transportation in open channel flows. U.S. Department
of Agriculture Technical Bulletin No. 1026, Sept., 4950.
Washington, U.S. Government Printing Office, 1951. 80 p.
-------
10. A solid waste recovery system for all municipalities.
Environmental Science & Technology, 5(2):109-111, Feb.
1971.
11. Converting solid wastes to electricity. Knviron»ental
Science & Technology. 4(8):631-633, Aug. 1970.
12. Pyrolysis of refuse gains ground. Environmental Science
& Technology. 5(4):310-312, Aprill971.
13. Reclaiming solid wastes for profit. Environmental
Science & Technology» 4(9):729-730, Sept. 1970.
14. Personal Communication. Erie County Health Department.
15. Sedimentation. In 0. M. Fair, J. C. Geyer, and D. A. Okun.
Water and wastewater engineering. v.2. Water purification
and wastewater treatment and disposal. New York, John
Wiley & Sons, Inc., [1968]. p.25(1-18).
16. Fairfield Engineering Company. Unpublished data.
17. Personal communication. Harden State Paper Company.
18. Golueke, C. G. Solid waste management: abstracts and
excerpts from the literature. \y 1 and 2, PubHc Health Service
Publication No. 2038. Washington,,U.S. Government
Fringing Office, 1970. U7 p.
19. Hansen, S, P., and G. L. Culp. Applying shallow depth
sedimentation theory. Journal, American Water Works
Association. 59(8):1134-1148, Sept. 1967.
20. Hatch, L. P. Flow of fluids through granular material:
filtration, expansion, and hindered settling. Transactions
of the American Geophysical Union, pt.2:536-547, 1943.
21. Hazen, A. On sedimentation. Transactions of the American
Society of Civil Engineers. 53:45-71, 1904.
22. Htmsaker, J. C., and B. G. Rightmire. Engineering applications
of fluid mechanics. chap.10. Drag. New York, McGraw-Hill
Book Company, Inc., 1947. p.182-216.
23. Ingersoll, A. C., J. E. McKee, and N. H. Brooks.
Fundamental concepts of rectangular settling tanks.
Transactions of the American Society of Civil Engineers,
121:1179-1204, 1956.
97
-------
24. Kenahan, C. B., P. M. Sullivan, J. A. Ruppert, and E. F.
Spano. Composition and characteristics of municipal
incinerator residues. U.S. Bureau of Mines Report of
Investigations No. 7204. [Washington], U.S. Department
of the Interior, Dec. 1968. 20 p.
25. Knockemus, W. K. Unpublished data.
26. Personal Communication. W. K. Knockemus.
27. Krumbein, W. C. Settling-velocity and flume-behavior of
non-spherical particles. Transactions of the American
Geophysical Union. p.621-633. 1942.
28. Kynch, G. J. A theory of sedimentation. Transactions of
th« Faraday Society. 48tl66-176, 1952.
29. Maude, A. D., and R. L. Whitmore. A generalized theory
of sedimentation. British Journal of Applied Physics,
9:477-482, 1958.
30. McNown, J. S., and J. Malaika. Effects of particle shape
on settling velocity at low reynolds numbers. Transactions of the
American Geophysical Union. 31(l):74-82, Feb. 1950.
31. Personal communication. Midwest Research Institute.
32. Merrill, A. B. Sedimentation basin research and design.
Journal of the American Water Works Association. 24(9):
1442-1463, Sept. 1932.
33. Rogus, C. A. Refuse collection and disposal in western
Europe; [w4 parts]. Public Works, 93(4):98-103; Apr. 1962,
93(5):99-104, May 1962; 93(6):139-143, June 1962; 93(7):
71-76, July 1962.
3*« Rouse, H., "Fluid Mechanics for Hydraulic Engineers"
a) Flow Around Immersed Bodies (pp 209-231)
b) Transport of Sedtment Xpp 327-350)
35. Sanner, W. S., C. Ortuglio, J. G. Walters, and D. E. Wolfson.
Conversion of municipal and industrial refuse into useful
materials by pyrolysls. U.S. Bureau of Mines Report of
Investigations 7428. [Washington], U.S. Department of the
Interior, Aug. 1970. 14 p.
36. Golueke, C. G. Solid waste management: abstracts and
excerpts from the literature. v.l and 2. Public Health
Service Publication No. 2038. Washington, U.S. Government
Printing Office, 1970. 147 p.
98
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37. Solid waste management: a list of available literature.
(Cincinnati), U.S. Department of Health, Education, and Welfare,
Dec. 1969. 27 p.; June 1970. 18 p.; Jan. 1971. 17 p.
38. (Solid waste research.) College Park, Md., U.S. Bureau of Mines.
39. Summer studies on management of solid wastes; final report v. 1.
Cambridge, Urban Systems Laboratory, Massachusetts Institute of
Technology, Sept. 1968. 54 p.
40. Thomas, H. A., Jr., and R. S. Archibald. Longitudinal mixing
measured by radioactive tracers. Transactions of the American
Society of Civil Engineers. 117:839-850, 1952.
41. Villemonte, F. R., G. A. Rohlich, et al. Hydraulic and removal
efficiency in sedimentation basins. Proceedings; Third International
Conference on Water Pollution Research, Munich, 1966.
42. Reclaiming refuse; efforts to save, reuse waste products slowed by
variety of problems. Wall Street Journal. 175(122):!, June 23, 1970.
99
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ADDITIONAL' SOURCE MATERIAL
This list of supplemental literature has been prepared from the
updated (October, 1971) master bibliography, Solid Waste
Management: A List of_ Available Literature, Report SW-58.12 of
the Environmental Protection Agency. Items cited here contain
information particularly relevant to the material in this report.
*
The numbering adopted herein corresponds to that employed in
Report SW-58.12. ,
2. Applying technology to unmet needs; report on the solid waste
problem. Technology and the American economy; report of the
Commission. National Commission on Technology, Automation,
and Economic Progress. Appendix v. 5. Washington, U. S.
Government Printing Office, 1966. 12 p.
8. Composting developments in the United States. J. S. Wiley and
0. W. Kochtitzky. Compost Science, 6(2):5-9, Summer 1965.
- 11. Development of construction and use criteria for sanitary land-
fills; an interim report. County of Los Angeles, Department of
County Engineer. Cincinnati, U.S. Department of Health, Education,
and Welfare, 1969. [267 p.]
\ 15. Experimental composting research and development; joint U.S.
Public Health Service — Tennessee Valley Authority Composting
Project, Johnson City, Tenn. Washington, U.S. Government
Printing Office, 1968. Flyer. 6 p.
16. The Federal solid waste demonstration program. D. M. Keagy.
[Cincinnati], U.S. Department of Health, Education, and Welfare,
[1968]. 13 p.
>
17. Gainesville compost plant; an interim report. Gainesville
Municipal Waste Conversion Authority, Inc. Cincinnati, U.S.
Department of Health, Education, and Welfare, 1969. [345 p.]
- 100 -
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26. The national solid wastes survey; an interim report. R. J.
Black, A. J. Muhich, A. J. Klee, H. L. Hickman, Jr., and R. D.
Vaughan. [Cincinnati], U.S. Department of Health, Education,
and Welfare, [1968]. 53 p.
28. Preliminary data analysis; 1968 national survey of community
solid waste practices. A. J. Muhich, A. J. Klee, and P. W.
Britton. Public Health Service Publication No. 1867. Washington,
U.S. Government Printing Office, 1968. 483 p.
32. The public health aspects of solid waste disposal. R. J.
Anderson. Public Health Reports, 79(2):93-96, Feb. 1964.
>
33. Quad-City solid wastes project; an interim report, June 1, 1966
to May 31, 1967. Cincinnati, U.S. Department of Health, Education,
and Welfare, 1969. [181 p.]
i
41. Research activities of the solid wastes program of the Public
Health Service. A. W. Breidenbach. [Cincinnati], U.S. Department
of Health, Education, and Welfare, [1968], 16 p.
43. A review of sanitary landfilling practices in the United States.
R. J. Black. In Proceedings, Third International Congress,
International Research Group on Refuse Disposal, Trento (Italy).,
May 24-29, 1965. [Temi Press.] p. 40-47. [Published in English,
German, French, and Italian editions.]
53. Solid waste handling in metropolitan areas. [W. E. Gilbertson,
.. R. J. Black, L. E. Crane, and P. L. Davis.] Public Health Service
Publication No. 1554. Washington, U.S. Government Printing Office,
1966. 41 p.
55. Solid waste management/composting; European activity and American
potential. S. A. Hart. Public Health Service Publication No. 1826,
Washington, U.S. Government Printing Office, 1968. 40 p.
57. Solid waste reduction/salvage plant; an interim report; City of
Madison pilot plant demonstration project, June 14 to December
31, 1967. Cincinnati, U.S. Department of Health, Education, and
. Welfare, 1968. 25 p.
61.
Some specialized equipment used in European compost systems. J.
S. Wiley. Compost Science, 4(1):7-10, Spring 1963.
- 101 -
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69. The Tezuka refuse compression system; a preliminary report.
American Public Works Association Research Foundation. Cin-
cinnati, U.S. Department of Health, Education, and Welfare,
1969. 47 p.
97. Analysis of solid waste composition; statistical technique to
determine sample size. D. E. Carruth and A. J. Klee.
[Cincinnati], U.S. Department of Health, Education, and
Welfare, 1969. 25 p.
102. Air classification for reclamation processing of solid wastes.
R. A. Boettcher. ASME Paper No. 69-WA/PID-9. Presented at
Winter Annual Meeting, American Society of Mechanical Engineers,
Los Angeles, Nov. 16-20, 1969. 12 p.
103. Economics of solid waste investment decisions. R. M. Clark.
Journal of the Urban Planning and Development Division, Proc.
ASCE, 96(UPI):65-69, Mar. 1970.
108. The Federal solid wastes program. R. D. Vaughan. Civil
Engineering, 39(2):69-71, Feb. 1969.
112. Policies for solid waste management. National Academy of Engi-
neering- -National Academy of Sciences. Public Health Service
Publication No. 2018. Washington, U.S. Government Printing
Office, 1970. 64 p.
"114. Solid waste processing; a state-of-the-art report on unit opera-
•-., tions and processes. R. B. Engdahl. Public Health Service
Publication No. 1856. Washington, U.S. Government Printing
Office, 1969. 72 p.
\ 116. Process in solid waste management and needed developments. L. W.
Lefke. In Proceedings; 8th Annual Environmental and Water
Resources Engineering Conference,. Nashville, June 5-6, 1969.
Technical Report No. 20, Vanderbilt University, p. 107-118.
Reprinted, [Cincinnati], U.S. Department of Health, Education,
and Welfare, 1970. 16 p.
119. Reuse of solid wastes: a major solution to a major national prob-
lem. R. D. Vaughan. Waste Age, 1(1):10, 14-15, Apr. 1970.
126. Cellulolytic activity in municipal solid waste composting. F. J.
Stutzenberger, A. J. Kaufman, and R. D. Loss in. Canadian Journal
of Microbiology, 16 (7):553-560, July 1970.
- 102 -
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128. Comprehensive studies of solid waste management; first and
second annual reports. C. G. Golueke and P. H. McGauhey.
Public Health Service Publication No. 2039. Washington, U.S.
Government Printing Office, 1970. 245 p.
132. Financing municipal solid waste management systems. R. M. Clark
and R. 0. Toftner. .Journal of the Sanitary Engineering Division,
Proc. ASCE, 96(SA4):885-892, Aug. 1970.
ii>
133. Sample weights in solid waste composition studies. A. J. Klee,
and D. Carruth. Journal of the Sanitary Engineering Division,
Proc. ASCE, 96CSA4) :945-954, Aug. 1970. '.
>
169. American composting concepts. P. H. McGauhey. Public Health
Service Publication No. 2023. Washington, U.S. Government
Printing Office, 1971. 23 p.
170. The role of nonpackaging paper in solid waste management, 1966
to 1976. W. E. Franklin. Washington, U.S. Government Printing
Office, 1971. 76 p.
177. Recovery and utilization of municipal solid waste; a summary of
available cost and performance characteristics of unit processes
and systems. N. L. Drobny, H. E. Hull, and R. F. Testin. Public
Health Service Publication No. 1908. Washington, U.S. Government
Printing Office, 1971. 118 p.
"178. Comprehensive studies of solid waste management; third annual
report. C. G. Golueke. Washington, U.S. Government Printing
Office, 1971. 201 p.
179. Plastic wastes in the coming decade. H. H. Connolly. Washington,
U.S. Government Printing Office, 1971. 26 p.
180. St. Louis power plant to burn city refuse. F. E. Wisely, G. W.
Sutterfield, and D. L. Klumb. Civil Engineering, 41(l):56-59,
Jan. 1971.
187. Rubber reuse and solid waste management. R. J. Pettigrew, F. H.
Roninger, W. J. Markiewicz, and M. J. Gransky. pt. 1 and 2.
[Public Health Service Publication No. 2124.] Washington, U.S.
Government Printing Office, 1971. 120 p.
- 103 -
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JL."
196. Resource recovery--a new solid waste management philosophy and
technology. J. T. Talty. Presented at the 10th Annual
Environmental and Water Resources Engineering Conference,
Vanderbilt University, Nashville, June 1971. [Cincinnati], U.S.
Environmental Protection Agency. 11 p.
212. Composting of municipal solid wastes in the United States. A. W.
Breidenbach. Washington, U.S. Government Printing Office, 1971.
103 p.
222. New chemical concepts for utilization of waste plastics. M. E.
Banks, W. D. Lusk, and R. S. Ottinger. Washington, U.S.
Government Printing Office, 1971. 129 p.
- i fU -
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SECTION X: APPENDICES
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APPENDIX A
TYPICAL COMPOSITION OF A COMPOSITE
MUNICIPAL REFUSE (18)
PERCENTAGE BY WEIGHT
garbage
tin cans
other metals
glass
stone, c
ashes, dirt
paper
rags
grass*
15%
5%
Is 2%
2%
amics 1%
t 5%
54%
0.6%
4.0%
brush*
greens*
ripe leaves
wood*
leather*
rubber*
plastics*
oils, paint*
linoleum*
1.5%
1.5%
5.0%
2..4%
0.5%
0.6%
0.7%
0.8%
0.1*
*These categories have been taken from am expanded table
in the same source document. Their inclusion here accounts
for the failure of this breakdown to total exactly 100%.
. 105 -
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APPENDIX B
SELECTED CENTERS OF RELEVANT-TECHNOLOGY
NAME AND CITY
Visited by members of the project:
Altoona Composting Plant
Altoona, Pennsylvania
B. J. Fibres, Inc.
Santa Anna, California
Black Clawson Company
Middletown, Ohio
Bureau of Mines
College Park, Maryland
Clean Steel, Inc.
Long Beach, California
Garden State Paper Company
Pomona,. California
Hercules, Inc.
Wilmington, Delaware
Los Angeles By-Products
Los Angeles, California
Public Works Department
Madison, Wisconsin
Stanford Research Institute
Irvine, California
USDA Forest Products Laboratory
Madison, Wisconsin
TECHNICAL COMPETENCE
Composting of municipal solid
wastes (see page 18)
Fiber reclamation from fiber
products
Fractionation of municipal
solid wastes (see page 18)
Pyrolysis of solid wastes
(see page 19)
Steel recovery from junk
cars (see page 7)
Newsprint manufacture from
recovered fiber (see page 18)
Composting and pyrolysis of
solid wastes (see page 19)
Tin can recovery from land-
fills (see page 9)
Preparation of solid wastes
for open landfill (see page 15)
Dry separation of solid wastes
(see page 23)
Manufacture of paper from fiber
recovered from solid wastes
Other Relevant Centers:
The Aluminum Association
New York, New York
Incineration and pyrolysis of
solid wastes with mineral
recovery (see page 19)
- 106 -
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NAME AND CITY
Battelle Memorial Institute
Columbus, Ohio
Bureau of Mines
Pittsburgh, Pennsylvania
Combustion Power, Inc.
Menlo Park, California
Metropolitan Waste Conversion Corp
Houston, Texas
Monsanto's Enviro-Chem System
St. Louis, Missouri
TECHNICAL COMPETENCE
Market identification for
materials recovered from
solid wastes
Mineral recovery from
incinerator residues
(see page 19)
Production of electricity from
solid wastes (see page 19)
Composting of municipal solid
wastes (s.ee page 17)
Pyrolysis of solid wastes (see
page 19)
- 107 -
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A P P E N D I X C
ALTERNATIVE METHOD OF METALLIC/NONMETALLIC SEPARATION
As an alternative for the separation of metallic particles
from non-metallic particles, the following system is suggested.
It is hoped that, because of the limitation on the metal
detecting area, this separation system will be-more effective.
After the separation of ferrous particles, the remaining
part of the feed material will be narrowed on the belt. In a
limited area, depending on the detection of a metal or non-metal
particle, air jets over the solonoid valves can be controlled so
that metals and non-metals will be separated to either side of
the sorting conveyor.
The plate-type search coil of Applied Electronics can be
the metal detector if sensitivity adjustment permits. Otherwise
the Proxi-Tron Electronic Proximity Detector of Automation Devices,
Inc., or the Proximity Sensing Head of Electro Products Lab, Inc.,
may be used.
For particle detection, the Lite-Ton Photoelectric or Beam-
tron proximity detector of Automation Devices, Inc., may be used.
On the solonoid valves, for more economical and dependable
operation, Magnelatch types are recommended.
For more reliable operation solid-state-type relays should
be selected.
- 108 -
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