•O
.y
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-93/175 f,
August 7993 ff-'
Technologies
Case Studies
cr_
-------
-------
EPA/600/R-93/175
August 1993
INNOVATIVE CLEAN TECHNOLOGIES CASE STUDIES
PROJECT REPORT
EPA Cooperative Agreement No. CR-817670
Project Officer:
Kenneth R. Stone
Office of Research and Development
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
This study was conducted in cooperation with the USEPA Office of Small and
Disadvantaged Business Utilization
Risk Reduction Engineering Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
Printed on Recycled Paper
-------
DISCLAIMER
The information in this document has been funded wholly or in part by the
United States Environmental Protection Agency. It has been subjected to peer and
administrative review, and it has been approved for publication as an EPA document.
Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
-------
FOREWORD
Today's rapidly developing and changing technologies and industrial products
and practices frequently carry with them the increased generation of materials that, if
improperly dealt with, can threaten both public health and the environment. The U.S.
Environmental Protection Agency is charged by Congress with protecting the Nation's
land, air and water resources. Under a mandate of national environmental laws, the
Agency strives to formulate and implement actions leading to a compatible balance
between human activities and the ability of natural systems to support and nurture life.
These laws direct EPA to perform research to define our environmental problems,
measure the impacts, and search for solutions.
The Risk Reduction Engineering Laboratory is responsible for planning,
implementing, and managing research, development and demonstration programs to
provide and authoritative, defensible engineering basis in support of the policies,
programs, and regulations of the EPA with respect to drinking water, wastewater,
pesticides, toxic substances, solid and hazardous wastes, and Superfund-related
activities. This publication is one of the products of that research and provides a vital
communication link between the researcher and the user community.
This report summarizes projects supported by the RREL to promote the
development of innovative pollution prevention technologies and techniques by small
businesses. The reader is encouraged to contact the individual developers listed in
each summary for more information regarding their process or product.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
in
-------
ABSTRACT
The innovative Clean Technologies Case Studies contained herein are the
products of the "Pollution Prevention by and for Small Business" Program (P2SB)
The P2SB was an outreach program directed to small businesses that had developed
innovative concepts for pollution prevention in their industries. The P2SB focused on
high-risk concepts without emphasis on media or industry in order to provide an open
program where ground-breaking concepts were given a fair opportunity.
The P2SB provided awards of up to $25,000 to assist small businesses for
conducting their own demonstrations of pollution prevention techniques and
technologies, and for advancing their products towards a practical stage.
In its first year, the P2SB funded projects in a variety of industries across the?
nation. This publication provides a history of the P2SB and lists case histories of the
projects funded in the first year. A second publication covering those projects funded
in the second (and final) year of the program is currently being finalized.
IV
-------
TABLE OF CONTENTS
Definition of Electrically Conductive Adhesives for the
Replacement of Tin-Lead (Solder) Joints in
Electrical Systems
Williams Werther, Interconnect Systems, Inc. .
Resource Conservation via Closed Insulated Pallet System
for Greenhouse and Nurseries
James Robbins, Briggs Nursery, Inc 11
Reclamation Facility for Waste Lithographic Ink
William Jacob, Ink Engineering Services 21
Total Lubricant Control System for Recycling Used Lubricants
Stephen McCollister, McCollister and Company . . . 28
The Agitair Dispenser as a Substitute for Household Aerosol
Dispensers
John V. Mizzi, Omnific International Limited 34
Recycling Valuable Components from Used Television Cable
Joe Kay, PAC Recycling 43
The Coldcut™ Process to Eliminate the Use of Hazardous
Machining Fluids
Timothy Palmer, Shamrock Industrial, Inc », • • • 52
Recycling Radiation-Curable Organic Waste by Casting
Structural and Decorative Objects
Harry Katz & Radha Argarwal, Utility Development Corporation ......... 64
ling Ink Wastes from Packaging Gravure Printing
William M. Jones, Resource Recycling and Remediation, Inc 72
Hydrocyclone Technology to Reduce Plant Pathogens in Irrigation
Water
Roy D. Lister, Hydro-Separation Systems, Inc. 79
Managing Wood Preserving Waste Streams Using the Enviro-Clean
Process
Tom Lewis, Lewis Environmental Services, Inc 92
Membrane Technology for Pollution Prevention in a Zinc Casting
Tubbing Operation ^
Kristen Whelan, Miniature Casting Corporation 102
-------
Eliminating Waste Discharge in a Reel-to-Reel Electroplating
Shop
Kenneth Marino, Orbel Corporation 113
In-Field, on Board, Dry Granular Herbicide Impregnation
John Brodman, Walton Agri-Service, Inc. 120
Waste Minimization in Electropolishing: Electrodeposition
and Process Control
Thomas Pierpont, Pier-Sol, Inc. 130
vi
-------
ACKNOWLEDGEMENTS
The Office of Research and Development has supported the P2SB in
cooperation with the Office of Small and Disadvantaged Business Utilization and is
grateful for the efforts of Karen V. Brown, EPA's Small Business Ombudsman, who
and coordinated support for this program. Through this office the support of the
following trade associations is acknowledged:
National Small Business United
Small Business Legislative Council
National Automobile Dealers Association
Independent Lubricant Manufacturers Association
American Wood Preservers Institute
Institute of industrial Launderers
National Tooling and Machining Association
Printing Industnes of America, Inc.
International Fabricare Institute
Synthetic Organic Chemical Manufacturers Association
Chemical Specialties Manufacturers Association
National Association of Metal Finishers
Chemical Producers and Distributors Association
National Federation of Independent Businesses
National Fertilizer Solutions Association
National Association of Truck Stop Operators
Society of Plastics Industry, Inc.
Graphic Arts Technical Foundation
American Galvanizers Association
The support to small businesses provided by Angel Martin-Dias at the Center
for Hazardous Materials Research is appreciated. The chapters covering individual
case histories were written by Ms. Martin-Dias, and CHMR retains copies of individual
reports. Support for the commercialization of selected technologies, which was
beyond the scope of P2SB, was provided by National Environmental Technology
Applications Center (NETAC). The advice and expertise provided by the American
Institute for Pollution Prevention (AIPP) was invaluable to the selection process.
This report was compiled and finalized by Dr. Rada Olbina. Her efforts are
greatly appreciated.
VII
-------
INTRODUCTION
In 1989, the U.S. Environmental Protection Agency established a 2% Set-aside
Program to fund pollution prevention initiatives from across the Agency. These set-
asides were instituted to encourage the research, development and demonstration of
pollution prevention concepts, techniques and technologies nationwide.
One such initiative, Pollution Prevention by and for Small Business (P2SB) was
proposed by the Office of Small and Disadvantaged Business Utilization (OSDBU) with
the support of the Office of Research and Development (ORD). This initiative was
selected for -funding under the pollution prevention 2% Set-aside, with co-funding
provided by ORD. The P2SB was managed through a cooperative agreement with
the Center for Hazardous Materials Research (CHMR), and some of the P2SB small
businesses received additional support for the commercialization of their technologies
through the National Environmental Technology Applications Center (NETAC)
Nineteen trade associations supported the program though promotion advise and
information transfer.
The P2SB provided awards of up to $25,000 to assist small businesses for
conducting their own demonstrations of pollution prevention techniques and
technologies, and for advancing their concepts to a practical stage. The P2SB was a
three-year program, ending September 1993, with awards being made in the 1991 and
1992 Fiscal Years of the Federal Government. This publication covers those projects
completed from the 1991 year, and a later volume will be published for the 1992
projects.
The P2SB small business applied their own knowledge and expertise in the
field to structure their projects and data collection activities in a manner they
determined would provide the most effective means of furthering the development of
their concepts. The reader should be aware that the data provided in these
summaries are not the results of third party evaluations.
. ^ ~,T]Vtin~,nouse demonstrations were completed in 14-16 months and reports filed
with CHMR which in turn developed research briefs for Agency review. These
research briefs have been re-organized into the chapters of this publication Of the 15
technologies provided, 8 are considered to be source reduction oriented while the
other 7 are classified as recycling/reuse. The technologies are considered promising
research and development concepts, and while several have advanced towards
commercialization, others require further investigation and testing. All are presented
to provide the reader the opportunity to contact the small business demonstrator for
potential uses.
The success of the P2SB program depends on the involvement of the trade
associations who sponsor presentations by the participating small businesses at
annual conferences and regional workshops. This initiative was developed to support
critical pollution prevention efforts in a variety of facilities and industries that might not
otherwise have the chance or the resources to reduce wastes or to test and
implement their innovative ideas. The P2SB was an attempt to support promising
ventures and encourage further development. It also expanded EPA's knowledge of
pollution prevention needs in different sectors, supporting government, business and
public cooperation in finding ways to prevent pollution.
viii
-------
DEFINITION OF ELECTRICALLY CONDUCTIVE ADHESIVES
FOR THE REPLACEMENT OF
TIN-LEAD (SOLDER) JOINTS
IN ELECTRONIC SYSTEMS
by
William Werther
Interconnect Systems, Inc.
Simi Valley, CA 93065
ABSTRACT
Tin-lead compounds (solder) and fluxes containing hazardous substances are
commonly used in the printed circuit board industry to "connect" or form conductive
electrical joints within electronic packages. This manufacturer of electronic systems
proposes to replace the tin-lead solder joints formed using conductive materials
(adhesives) created by combining organic polymers (epoxies, thermoplastics, etc.) with
conductive fillers. Successful development of this process will eliminate the use of
lead-bearing compounds and hazardous fluxes, as will as eliminate the need for
cleaning solvents such as Freon and methylene chloride commonly associated with
the tin-lead soldering process.
INTRODUCTION
PROJECT DESCRIPTION
Outline of Product
Interconnect Systems, Inc. (ISI) manufactures "packages* which mechanically
protect and electronically interconnect semi-conductor chips as well as passive
components. These packages are used in a wide variety of electronic systems,
including personal computers, automobiles, medical equipment, and
telecommunications equipment.
Typical packages are constructed by mating together an array of metal contacts
(pins), which are molded into a carrier, and a printed circuit board. The printed circuit
board is designed with an array of holes to mate with the array of pins (through-hole
configuration). Electrical, contact is made between the plated hole of the printed circuit
board and the pin via a tin-lead solder and reflow process.
Another type of package involves a molded array of pins and a printed circuit
board, but the circuit board does not have holes into which the pin array is inserted.
Rather, the pin array is mounted to flat pads on the surface of the circuit board. IS!
also produces "adaptor" packages which are designed to convert a surface-mounted
chip to a through-hole configuration.
-------
o>
5?
u.
o
-------
In both cases, tin-lead spider typically provides the "adhesive" to form
conductive electrical joints within the electronic packages. Cleaning solvents, such as
freon and methylene chloride, are used to clean the solder flex from the finished
package.
This project seeks to replace the tin-lead solder and the related hazardous
cleaning solvents with an organic polymer adhesive containing conductive fillers in
this case, silver.
Figure 1 illustrates several views of an electronic package with surface joints
with conductive organic adhesive used to form the joint.
APPLICATION
Process Replaced
Surface soldering is one method for joining and creating the electrical
connection between the pin array and the printed! circuit Attempts to produce
samples of an adaptor package by soldering indicated problems associated with the
differential coefficients of thermal expansion between the molded pin array and the
printed circuit board.
ISI believes that during the soldering process, the solder reflows and quickly
solidifies, thus fixing the two components at a relatively high temperature (about
220°C). The components then contract to their initial dimensions at a differential,
inducing warp into the assembly. Because the solder fixes the components together
the warp is the only way to reduce the stress caused by the differential contraction.
In addition to these soldering difficulties, ISI also recognized several
environmental hazards associated with the use of tin-lead solder compounds.
1. Lead, a heavy metal, needs to be controlled in terms of disposal and
employee exposure.
2. Fluxes used in the soldering process allow the tin-lead to adhere and coat
the surfaces necessary for electrical contact. Typical rosin-based fluxes
contain hazardous substances including organic acids, aliphatic solvents,
and halogens.
3. Flux residues need to be cleaned post-soldering. Typical chemistry used to
clean fluxed include Freon, Freon/alcohol mixtures, and methylene chloride.
Prior to the start of this project, ISI instituted manufacturing and materials
handling procedures to minimize the waste of these hazardous constituents.
1. Stencil printing of solder "paste" (solder + flux) to deposit solder only in
those areas required for the given assembly.
2. Design of solder joint geometry to minimize solder volume.
-------
3. Controlled solder reflow via forced convection heating to eliminate burned
and difficult to remove flux.
4. Use of non-halogenated fluxes, where possible.
5. Gasketed sealing of the flux cleaning solution to minimize evaporation into
the atmosphere.
6. Recycling of Freon/alcohol solution through a continuous distillation
process.
Even with these precautions, the use of this process and materials represents
ISI's only operation involving hazardous materials and wastes.
Wastes Prevented
ISI has replaced the tin-lead solder joints with conductive materials created by
combining organic polymers (epoxies, thermoplastics, or silicones) with conductive
fillers (in this case, silver). This allows the elimination of:
Lead containing compounds
Fluxes
Freon as a cleaning solvent
A measurable waste product
In addition, non-environmental benefits associated with the use of conductive
adhesives include:
Simplified production process
lower process cost
Lower materials cost
Enhanced thermal performance range in the finished product
Cross Segment Uses
Conductive adhesives would be suitable in several types of applications,
including:
1. Any application where the components to be attached are thermally
sensitive, for which the relatively low processing temperatures of organics
provide significant advantages over tin-lead solder.
2. Any application for which the electrical joints need to absorb a significant
amount of mechanical stress.
3. Applications for which the elimination of soldering results in an economic
benefit.
4. Applications for which soldering is not technically feasible.
-------
PROCEDURE
DEMONSTRATION
Testing requirements for adaptor packages are simple: if the electrical
resistance in the part formed between the metal pad on the printed circuit board and
the pin contained in the molded array is less than .3 ohm, the package will function
correctly. Higher resistance values will have an effect on the chip's thermal
characteristics as well as the electrical speed of the chip.
Because the electrical effects of the circuit board have already been thoroughly
characterized and shown to be quite acceptable (resistance values averaging less
than .05 ohm), the testing of the conductive adhesive joint is a simple matter of
placing probes at the tip of the pin and the top side of the circuit board (on the plated
hole directly above certain conductive adhesive joints), and taking resistance
measurements.
The first demonstration focused on the use of conductive adhesives in the
"through-hole" molded pin array to printed circuit board geometry. Because the pin is
inserted into a plated hole, the area of contact between the pin and the metallization
of the printed circuit board is relatively large.
IS! employed a variety of conductive organic adhesives for this type of
application without seeing significant differences in resistance in the electrical joint.
For example, conductive urethanes, a highly elastic material, seemed to react very
similarly to conductive epoxy materials which are fairly rigid. Joint resistance fell in the
range of less than .1 ohm.
ISI found it important that the conductive adhesive fill as much of the interface
between the pin and the plated hole as possible. This can be challenging as the
conductive material can potentially short to adjacent circuit geometry if too much
adhesive is used. This is one disadvantage in using conductive organics compared to
solder: the conductive organics flow during the thermal cure cycle into cavities,
whereas solder will form a fillet on areas of metallization only, and will not tend to
"jump" over areas of insulative separation.
The conductive adhesive was also tested on the adaptor packages as, in
addition to the motivation to eliminate solder for environmental reasons, the use of
solder in adaptor packages was creating a functional problem in the packages.
In using solder on an adaptor package, it is virtually impossible to maintain a
flat package through surface soldering of the pin array to the printed circuit board.
This is because these two component expand at differential rates during soldering,
and are fixed together by the solder before they have a chance to relax to their
original dimensions. This induces a rather significant warp into the package.
The use of a conductive adhesive can solve this warpage in two key ways:
1. The conductive adhesive cures at a much lower temperature than that at
-------
which reflow occurs. The differential expansion between the molded pin
array and the printed circuit board is much less.
2. An adhesive system can be chosen which has some flexibility to it, to take
up any small differential expansion between the pin array and th© printed
circuit. Conversely, a solder joint is very rigid.
The main problem encountered in pursuing a conductive adhesive system for
adaptor products was a lack of consistency in joint resistance due to several factors:
1. Variations in pin height in the molded pin array result in variation in the
distance over which the conductive organic must form an electrical path,
This, in turn, results in resistance variations.
2. If stress is induced in the joint, and the conductive adhesive is flexible
enough, the resistance in the joint can be affected by changes in the
electrical path length, and effectively changes the bulk resistivity of the
conductive adhesive.
3. Cure properties have a significant effect on resistance properties. Higher
cure temperatures induce lower bulk resistance.
ISI made an initial choice of a conductive urethane from APTEK laboratories
(X-95022-A/B) and tested several variations of this material to develop a formulation
compatible with the current stencil soldering process. This process required a
viscosity which allowed the adhesive to dome above the surface of the circuit board
permitting greater contact area between the pin and the pad on the circuit board.
Initial results on the prototype fabrication of the adaptor assembly package
yielded widely varying resistance values from .5 to 4.0 ohms. This is quite high, as
the bulk resistance of these materials has been measured at .1 ohm/cm2.
After a variety of attempts (of limited success) to reduce th© resistance values,
the following factors were identified as potential causes:
1.. "Lubricant" coating on the silver filler used in the adhesive causing added
resistance.
2. Poor alignment of the silver filler.
3. Non-optimal cross-linking of th© polymer structure.
4. Too much flexibility in the adhesive, resulting in added resistance due to
materials elongation.
5. Oxidation/contamination of surfaces to be bonded.
In order to evaluate whether these factors were causing the resistance
problems, ISI assembled another set of adaptor packaged using a "semi-rigid" epoxy,
silver-filled (6500-1-PMF). The epoxy can be cured at higher temperatures than the
urethane materials.
6
-------
Using the epoxy system, 12 sample adaptor packages were evaluated in two
cure trials: an 8 hour cure at 120°C (a relatively low temperature for an epoxy), and a
2 hour cure at 150°C.
The average meter reading meter reading, resistance value in ohms, for the 8
hour cure samples was 1.081 ohms; for the 2 hour cure samples, the reading was
.175 ohms. These values clearly show the effects of cure temperatures on the
resistance values derived in the joints between the pins of the molded array and the
pads of the printed circuit. The average resistance on .175 ohms is not quite optimal,
but is likely acceptable for most relevant applications of this adaptor product.
Subsequent test runs indicated resistance values averaging below .1 ohm for
samples cured at 150°C.
PERFORMANCE RESULTS
Product Success: Product Quality Variance
In many practical applications, the organic adhesive material has significant
benefits over solder. For example, many adaptor packages will be subjected to
thermal conditions for which solder is unacceptable.
Considering that one of the project's goals was to have the resistance in the
electrical joints in the adaptor package be less than .3 ohms, the test results indicate
success.
However, when the number of joints in an adaptor package are considered, ISI
was concerned by the size of the "process window.8 To illustrate, an adaptor package
for the 68030 microprocessor contains 128 joints, each of which must exhibit
reasonable resistance. At the typical tested resistance values in a conductive
adhesive adaptor, even at three sigma statistical limits, there will be a nearly 25
percent defective adaptor condition, when it is considered that a single "bad" joint
renders the entire adaptor defective. As the chip which is attached to the adaptor may
be worth as much as several hundred dollars, this defect rate is certainly
unacceptable. Through the implementation of additional process controls, ISI is
working to reduce this defect rate.
Conditions That Impact Performance
Process control and defect rates reflect the current early stages of this
application. Additional testing should result in a refinement of materials used and
process control parameters for adaptor package applications.
A number of improvements are planned in the overall adaptor package and the
assembly package to further reduce the average resistance values and the standard
deviation of these values. These include:
1. Use of a molded pin base with lower Coefficient of Thermal Expansion
(CTE) to more closely match the CTE of the circuit board. This will reduce
the stress on the electrical joint and make the pin to pad interface
significantly more uniform.
-------
2. Use of point-to-point dispensing to deposit the conductive adhesive material
onto the pads of the circuit board. This will allow for a more "domed" joint
versus stencil printing (stencil printing is limited by the thickness of the
stencil in defining the height of the dome). This will increase the surface
area of attachment.
3. Work to further raise the cure temperature of the epoxy adhesive to allow
for tighter cross-linking of the conductive system, and thus lower bulk
resistivity. This has not been possible to date because of the CTE
problems defined above.
Tabulation of Data for Semi-rigid Epoxy
Data for the adaptor package trials involving variable time and cure
temperatures clearly show the effects of resistance values in the joints between the
pins of the molded array and the pads on the printed circuit. Results of these tests;
are summarized below in Table 1.
TABLE 1. Resistance Values
Sample #
1
2
3
4
5
6
7
8
9
10
11
12
Test Coupon*
Aveiage Ohms
Actual Average
(Subtract 0.6 typ. meter
resistance)
Meter Reading, Resistance Value in Ohms
8 Hours @ 120°C
1.0
2.9
1.6
2.5
1.6
1.0
3.0
1.2
1.3
1.2
0.8
2.0
30.0 @ 2 inches
1.681
1.081 ohms
2 Hours @ 150"C
0.7
0.7
0.9
0.7
0.8
0.7
0.7
0.7
1.3
0.7
0.7
0.7
1.8 @ 2 inches
0.775
0.1 75 ohms
*Not included in calculation of averages.
Each sample is the average of 128 joints.
8
-------
Cost/Benefit Analysis
In order to economically assess the benefits of conductive adhesive versus
solder on adaptor packages, the following data in Table 2 compares the costs
associated with the formation of electrical joints using the two processes.
TABLE 2. Cost Comparison of Solder Process Versus Organic Process
Process
Stencil/
Dispense*
Reflow/
Cure
Degrease
TOTALS
Solder Process Costs
Material
$0.130
0.000
0.170
0.300
L + OH
$0.083
0.140
0.050
0.273
Total
$0.213
0.140
0.220
0.573
Organic Process Costs
Material
$0.240
0.000
0.000
0.240
L + OH
$0.104
0.030
0.000
0.134
Total
$0.344
0.030
0.000
0.374
Basis: ISI P/N A68030-1-A Adaptor for Motorola 68030 Microprocessor 2,500 piece manufacturing lot
Includes solder and adhesive material costs.
L + OH = Labor + Overhead
This analysis assumes that the solder is applied in a paste form via stencil
printing, while the conductive adhesive is applied by point-to-point dispensing. The
solder is fused in the joint by Infrared Reflow; the conductive adhesive is cured in a
batch convection oven. Vapor degreasing is used to clean flux residues from the
soldered part. All costs assume that processes may be performed using existing
equipment.
On a purely economic basis, there is approximately a $.20 per adaptor cost
savings by using the conductive epoxy electrical joint method versus "standard"
soldering techniques. This represents a substantial (greater than 10%) savings on
overall production costs.
POLLUTION PREVENTION ASSESSMENT
Environmentally, ISI is working to eliminate ozone-depleting compounds from
the workplace as well as other materials which may have a detrimental effect on
employees. ISI will continue to pursue the elimination of Freon, lead, and fluxes from
their process.
Phase of Development
Adaptor packages are currently being sold by ISI, some with soldered joints;,
others with conductive adhesives, depending on the particulars of the application.
While most recent sales are of the soldered product, ISI anticipates no functional
limitations in the use of conductive organic adhesives outside of the constraints
-------
previously discussed.
The market for "custom" adaptors is difficult to estimate, as many variables
affect the use of these packages. ISI's best estimate is modest, in the range of $4-5
million.
The market for "standard" adaptors (applicable to many users for a specific
chip) is larger than the "custom" market. When considering the applications and
number of such chips in demand, a market of $50 million or more may be reasonable.
Barriers
Limitations in the use of conductive adhesives in adaptor products revolve
around ISI's ability to fine-tune the materials and processes to produce packages
which are functionally acceptable to a high yield and are reliable in long term use.
This involves two issues:
1.
2.
The maintenance of a reliable assembly in long-term quality control testing.
ISI feels this issue can be resolved, although resources have not yet been
devoted to its testing.
Perhaps the biggest constraint in the use of conductive organics is their
relatively poor mechanical characteristics. This is especially true if the material is
heavily filled with conductive material, silver, in this case;-this substantially weakens
the mechanical integrity of the adhesive. ISI's adaptor packages allow the electrical
joints sufficient mechanical integrity, as each pin contact is anchored into plastic, and
the entire plastic molded pin array is attached to the circuit board portion of the
adaptor via non-conductive adhesive.
For applications without severe mechanical constraints on the electrical joint,
conductive adhesive systems are a viable alternative to solder. While this types of
product may represent a small portion of the electronics industry, it may represent a
substantial volume of manufactured product.
The use of an electrically conductive organic adhesive as a replacement for
tin-lead solder is technically feasible for a variety of joint geometries, both through-hole
and surface mount. Resistance values in a "functionally feasible" region were
obtainable with proper choice of part geometry, adhesive, and processing conditions.
While initial results on long-term reliability look promising, additional work is
necessary before the process is capable of high volume manufacturing. This work is
currently in progress at ISI.
10
-------
RESOURCE CONSERVATION VIA GLOSSED INSULATED PALLET SYSTEM FOR
GREENHOUSE AND NURSERIES
by
Dr. James Robbins
Briggs Nursery, Inc.
Olympia,WA 98501
ABSTRACT
The Closed, Insulated Pallet System (CIPS) is an innovative alternative to the
traditional nursery and greenhouse practices for producing container-grown plants.
The CIPS, originally developed by an interdisciplinary research team, is designed to
eliminate the use of herbicides; eliminate water run-off or leaching in production areas;
reduce and conserve water, fertilizers, and control (growth regulating) chemicals;
reduce the single-use of plastic plant containers and polyethylene plastic film for
overwinter protection covers; and reduce heat energy required in greenhouse crop
production. Fertilizer uptake and movement within the enclosed root matrix of the
CIPS was characterized. In addition, the project examined the efficiency of fertilizer,
water, and energy use in CIPS as compared to the traditional, overhead sprinkler-
irrigated, spaced system.
INTRODUCTION
PROJECT DESCRIPTION
Nursery and greenhouse production of container grown plants involves the
intensive use of energy resources and agricultural chemicals. Inefficient or excess
application and retention of these resources in the plant system results in a relatively
large waste discharge of pollutants and resources from the production area.
The Closed Insulated Pallet System (CIPS) is an innovative alternative to
traditional nursery and greenhouse practices for producing container grown plants.
CIPS is designed to eliminate the use of herbicides; eliminate water runoff (leaching)
in production areas; reduce and conserve the use of water, fertilizers, and control
chemicals; reduce the single use of plastic plant containers and polyethylene film
overwinter protection covers; and reduce heat energy required in greenhouse crop
production.
A closed insulated pallet is most easily likened to an oversized insulated box. A
number of pre-spaced plants are suspended from the pallet lid and irrigated from
below using a capillary watering system. Fertilizer is applied to the media surface
prior to the surface being sealed with a moisture impermeable disc.
Rgure 1 is a cross section of a CIPS pallet showing an array of plant units with
roots enclosed within the closed integrated pallet. Plant snoots extend upward
through a seal in the pallet top that is essentially a continuous, water impermeable,
11
-------
light reflective, solar and thermal radiation opaque, insulating pallet top.
Figure 1. Cross Section of a CIPS Pallet
APPLICATION
A critical component of CIPS is the sealed media surface which protects
fertilizer ions from precipitation. Sealing the media surface establishes a protected ion
diffusion zone, eliminates the need for herbicides, and reduces the need for certain
insecticides and fungicides.
As plants require water, water is drawn up a capillary wick that is suspended in
the pallet reservoir and is subsequently taken up by the plant roots. The timing and
amount of fertilizer needed by the plant is also determined by the plant rather than
depending on elaborate monitoring systems or by guessing the plant's requirements.
A unique aspect of CIPS is that water and fertilizer needs are plant driven.
CIPS may be contrasted with the traditional overhead sprinkler-irrigation system
(TOSS) of plant production in which plants are grown in individual, spaced containers.
Water, often mixed with fertilizer and control chemicals, is applied using overhead
irrigation. Due to the spacing of the plant containers, much of the water falls between
the containers and is wasted. Water and nutrients also leach from the bottom of the
containers.
12
-------
PROCEDURE
DEMONSTRATION
Specific experiments proposed in this project focus on the following areas:
1. Develop budgets (balance sheets) for fertilizer, water, and control
chemicals in CIPS and TOSS.
2. Determine if nutrient movement in CIPS can be explained by diffusion, and
if stable chemical and water gradients are established in the media.
Experiments will utilize the beneficial fungus, Trichoderma harzianum, as a
bioassay to evaluate potential favorable niches within the CIPS media.
Two work plans were designed with the following parameters:
Work Plan #1
Experimental Design: 1 plant species x 1 media x 2 fertilizer rates x 2
production systems x 8 replicates. Experimental period was June 11, 1991 to August
14, 1991.
Plant: Zea mays (Golden Jubilee Corn) was selected as this species gains
biomass quickly, and limited time factors came into consideration in the project.
Media: Equal volumes of Douglas fir bark, peat, and perlite. Dolomite was
incorporated at a rate of 5 pounds / cubic yard.
Fertilizer Treatments: Osmocote®, an 8 - 9 month, coated, slow-release
fertilizer, analysis 18-16-12, was topdress applied in both production systems. Low
and high fertility rates were 10 and 20 grams of fertilizer per container, respectively.
Fertilizer prills were sewn into a nylon mesh bag to facilitate removal at the end of the
experiment.
Production Systems: CIPS and TOSS were compared.
CIPS: The pallet was divided into 16 units by placing a 23 x 23 centimeters white
plastic bucket under each of the 16 holes in the lid. The pallet bottom and individual
buckets were filled with water.
TOSS: Rigid, 1 gallon black, round plastic pots were situated on a gravel bed in a 2x
(1 can space between containers) spacing configuration.
Irrigation Systems: CIPS and TOSS were compared.
CIPS5: Plants were irrigated by a capillary mat irrigation system (plant driven uptake).
City tap water was added to the individual plant reservoirs 3 times during the
experimental period.
13
-------
TOSS: Individual containers were hand watered every 2 to 3 days with city tap water.
To simulate standard nursery irrigation methods, individual plants were irrigated with a
water volume that would result in a 40 percent leaching fraction.
Data Collection: Leachate (or reservoir) -The yolume of container leachate
(TOSS) was measured and a subsample analyzed for nitrate, ammonium, and
phosphate ions. Nitrate and ammonium were analyzed by ion selective electrodes;
phosphate was determined by the calorimetric method of Murphy and Riley. All data
quality was the responsibility of Briggs Nursery, and quality control was not subject to
EPA protocols.
Water Use: CIPS and TOSS were compared.
CIPS: Water use was determined using a clear glass tube in the reservoirs and the
volume calculated using dimensions from the individual reservoirs and the change in
reservoir height.
TOSS: Water use was determined by combining the actual volume of water applied to
the surface of each container with the calculated volumes of water that would fall
between containers in a 2x nursery spacing.
Media: Total nitrogen, ammonium-nitrogen, nitrate-nitrogen, extractable
phosphorus, and total phosphates were analyzed. Media samples were air dried and
sent to the Soils Testing Laboratory at Oregon State University (OSU).
Fertilizer Prills: Prills samples were air dried and sent to OSU Soil Testing
Laboratory for analysis (total N, total P).
Plant: Plant tissue samples were air dried, ground, and transported to the OSU
Plant Testing Laboratory for analysis (total N, total P).
Work Plan #2
Experimental Design: 4 treatments (+ plant / - fertilizer; + plant /+ fertilizer; -
plant / + fertilizer; - plant / - fertilizer) x 5 samples (4 media strata + reservoir) x 4
chemical analysis (K+, NOg., pH, EC) x 5 sample dates x 6 replicates. Media strata
samples: #1 (0-1 inch from surface); #2 (1-2 inches from surface); #3 (2-4 inches from
surface); #4 (4-6 inches - pouch bottom). Experimental period ~ April 21 - August 19,
1991. Experiments conducted in a greenhouse with no supplemental lighting; 18°C
days and 15.5°C nights.
Plant: Zea mays (Golden Jubilee Corn) was selected for the same reasons as
stated in Work Plan #1. Seedlings were watered as needed; no fertilizer was added.
17 day old com seedlings were transplanted into fabric pouches on April 20. The
media in the pouch was saturated with water and the pouch allowed to drain for 24
hours. Pouches were sealed in the pallets on April 21.
CiPS Root Pouches: 3 liter fabric pouches were constructed from lightweight,
spunbound polyolefin, Kimberly Clark NW401. Pouches were coated with a copper
hydroxide / latex paint suspension (100 grams Kocide 101WP per liter of dilute paint)
14
-------
to prevent roots from circling in the bag and from growing out through the fabric wall.
Container Medium: 1:1 (v:v) peatvermiculite mixture. Dolomite was added at
5.1 pounds/yard3.
Trichoderma harzlanunr. This non-parasitic, beneficial fungus was used in
these experiments as a biological assay for chemical and physical gradients (niches)
in the medium. All root medium treatments were inoculated with Trichoderma.
Fertilizer Treatments: Potassium nitrate (2 pounds N/yard3) and single
superphosphate (.3 pounds P/yard3) were divided between 3 fertilizer conservers.
Conservers were constructed from inverted Petri dishes and fabric netting; Polyolefin
fabric was secured to the open surface of the Petri dish by a rubber band. The fabric
chamber (called a fertilizer compartment) separated the fertilizer salts from direct
media contact and aided in retrieving the salts at the end of the experiment. Fertilizer
conservers were positioned near the edge of the container.
Irrigation: Water content of the medium in the fabric pouches was maintained
by capillary flow of water from the individual reservoirs to the fabric pouches by a Troy
Flowthru capillary mat.
Data Collection: The various treatment combinations were compared. The
media in each pouch was divided into 4 strata: the top 1 inch, the second 1 inch, the
next 2 inches, and the remainder of the media. These media samples, plus a 100
milliliter water sample from each reservoir, were analyzed for K+, NO^, pH, and EC.
A quantified recovery of Trichoderma harzianum was done on each media sample.
RESULTS AND DISCUSSION
PERFORMANCE RESULTS - WORK PLAN #1
Water Use: Reduced by 90 percent when com was grown in CIPS versus
experimental overhead irrigation system.
Fertilizer Budget: Overall N budget
CIPS: 87 percent of applied N could be accounted in the low fertility treatment; 80
percent of applied N could be accounted in the high fertility treatment.
TOSS: In the low fertility treatments, 94 percent of applied N could be accounted; in
the high fertility treatment, 91 percent of applied N could be accounted.
Shoot The percent of N based on final shoot weight is similar for TOSS and
CIPS grown plants.
TOSS.
Fertilizer: The amount of residual fertilizer (N) was lower in CIPS than in
15
-------
Media: CIPS had a greater amount of ammonium-N, nitrate-N, and extractable
phosphorus as compared to TOSS.
Leachate: In CIPS, no detectable increase in nitrate, ammonium, and
phosphate ions were noted, as compared to high levels recorded in TOSS.
Plant Growth: At the low fertility rate, pallet grown plants were 37 percent
larger than container grown plants. Under high fertility conditions, pallet plants were
27 percent larger. Plants had not developed to the point of producing seed during the
project period.
Chemicals: Although no chemical pesticides, insect or weed control materials
were applied during the experiment, a reduction in these inputs can be anticipated. In
CIPS, because the media surface is sealed, no herbicides are required.
PERFORMANCE RESULTS - WORK PLAN #2
In comparing data from CIPS and TOSS in nutrient movement by diffusion,
chemical and physical gradients (potassium; nitrate-nitrogen) pH, water content of the
media, and water use, the CIPS grown plants consistently displayed more efficiencies
than the TOSS plants.
One example of the available data sets is the potassium budget comparing CIPS and
TOSS as shown in Table 1. Although this test was not set up as a budget
experiment, calculations account for most of the applied fertilizer.
Table 1. Potassium Budget Comparing CIPS and TOSS (Meq K1)
Da?V-
30
59
88
120
30
59
88
120
120
+P
+P
+P
+P
-P
-P
-P
-P
TOSS
<• «fc % %•>• *"
159.42
105.23
95.99
76.82
179.91
158.18
106.37
91.00
18.92
X fiSSwFSfwjF "
^***&T;
-2.77
-0.89
-0.91
24.42
49.35
87,20
132.48
155.44
NA
;; D&fe?, '*
5&.M " ^ •*•••-
49.06
11.34
1.87
1.32
28.07
12.85
2.03
1.85
NA
^shoia* f
'**'•• - , ,
11.78
55.47
95.58
90.12
71.82
Toteal;jj|
217.49
171.14
192.53
192.68
257.33
258.23
240.88
248.29
90.74
90.62*
71.31
80.22
80.29
107.22
107.60
100.37
103.43
37.81
1 Values are the mean of six replicates with the native K+ subtracted, in meq K+/unit (mecg/pouch,
meq/reservoir, etc.)
2 Treatments:
+P = com plant, +24.3 grams KNO3 fertilizer (240 meq KNOg/pouch)
16
-------
-P = no plant, + fertilizer (240 meq KNO./pouch)
TOSS = plant in open container on bench receiving overhead watering (traditional production
method)
3 Meq K+ in petri dishes were estimated from dry weights (9.89 meq/gram KNO-^pouch)
4 Potassium concentrations in plant shoots were estimated to be 2 percent of shoot dry weights.
5 The quantity of K in the roots was not determined of included in the media analyses. The
unaccounted for K was probably in the roots.
Disease control within CIPS in another area of concern. The potential for crop loss
from soil pathogens in the enclosed root matrix because of the impracticality of
applying sprays or soil drenches after disease occurs necessitates effective methods
of prevention. The non-parasitic fungus, Trichoderma harzianum, offers a biological
means of control which can be incorporated into the media.
Trie objectives of this portion of the study were to learn if nutrient movement can be
explained by diffusion, if stable chemical and physical gradients are established within
the media, and if Trichoderma harzianum can persist is the CIPS environment.
At the beginning of the experiment, there was some concern that the copper
hydroxide-latex coating on the fabric pouches might have an adverse affect on the 7.
harzianum. Myceluim was found growing on the outside of the of the treated fabric
pouches at day 120, and when the mycelium was plated on selective media,
Trichoderma were recovered. Comparing Trichoderma between fabric pouches in
CIPS (copper treatment) and TOSS (no copper) on the bench indicates that
populations on the fungus tend to be higher in CIPS.
COST ANALYSIS
Annual costs for 6 different nursery production models were compared in a
differential cost analysis as shown in Table 2. The six models ranged from the
traditional open container nursery to innovative automated closed production systems.
Models were from the U.S. and the Netherlands and accounted for average local
costs.
The preliminary analysis indicated that the annual differential costs for CIPS with
partial automation are as low as or lower than those for the other 5 production
systems compared. Factors compared include land utilization costs; surface
preparation of production area; mechanization; plant container costs, specific labor
costs; chemical costs; irrigation water costs; and annual plant shelter costs.
Selected annual costs that vary among the six nursery production models were
compared in the differential cost analysis. The six nursery models evaluated ranged
from the traditional, open container nursery to innovative, automated, closed
production systems. Model 1 is the Dutch traditional container nursery (type I) with
overhead irrigation, no recycling of wastewater and structured plant overwinter
protection (tunnels). Model 2 is the U.S. traditional nursery with overhead irrigation,
structured overwinter plant protection (poly-covered quonsets), no recycling of
17
-------
irrigation wastewater. Model 3 is the Dutch traditional nursery (type II) with recycled
wastewater. Model 4 is the U.S. traditional nursery with recycled wastewater. Model
5 is the Dutch "closed" system nursery (type VI) with concrete surfaced production
beds, ebb and flow irrigation, automated gantry for handling pallet-grouped containers
and production area covered by tunnels (Model 5.1) or by a shelter house with four
temperature zones and a convertible top (Model 5.2). Model 6 is the U.S. Closed
Integrated Pallet System (CIPS) with CIPS placed by automated gantries on bare-
earth production blocks; overwinter plant protection provided by structureless
polyethylene film (Model 6.1) or by a shelter house with four temperature zones
(Model 6.2); no waste discharge from closed pallets. Annual costs for systems 5 and
6 are presented for both 1 year's growth and for 2 year's growth in 1 year. The
"shelter house" of Models 5.2 and 6.2 is included with the assumption that it will make
it possible to obtain 2 years of plant growth in 1 year. The annual cost per crop per
pallet-acre is obtained by dividing the total annual cost by 2. Nursery Models #1, #3,
and #5 are based on a study a the Boskoop Research Station for Nursery Stock.
Nursery Models #2 and #4 are based on the study of Taylor, et al.
Annual costs hypothesized to vary significantly by system and compared included:
(1) Land Utilization Costs. The percent of the producton area (plant beds, aisles
roadways, reservoirs) that is in plant beds varies with the selected plant handling
system. The area of land purchased to provide a given area of plant beds is system
dependent. Two land purchase values are used in each model: (a) $1,850 per acre is
representative of land values in the U.S. (b) $25,293 per acre is representative of
land values in the Netherlands. (2) Surface Preparation of Production Area. Costs of
grading, leveling, gravel or.concrete surface, irrigation system, and water
treatment/recirculation system are system dependent. (3) Mechanization required
(e.g., tractors, wagons, gantries, train conveyors) is system dependent. (4) Plant
Container Costs. Pallets, rigid containers, pouches, and the like are system
dependent. (5) Specific Labor Costs for pest management, plant movement,
irrigation/fertilization are system dependent (6) Chemical Costs for fertilizers and
pesticides are system dependent. (7) Irrigation Water Costs. Gallons of water
purchased, variable costs of operating water recycling and water treatment, etc. are
system dependent. The costs for water treatment (i.e., filtering, chlorination, pumping)
are included in Model 4. The cost of water varies with location ranging from (a) $140
per million gallons to (b) $1,200 per million gallons, (8) Annual Plant Shelter Costs.
Shelters such as overwintering tunnels, quonset houses, or 100 percent shelter house
are system dependent.
In this study, all plant beds (bed-acres, pallet-acres) were covered with winter shelter
systems. The comparisons include only cost items that vary significantly among the
systems.
Based on initial assumptions, the preliminary analysis indicated that the annual
differential costs for the CIPS with, partial automation are as low as or lower than
those for the other 5 production systems.
-------
Table 2. Selected Annual Costs Per Bed-acre for Six Nursery Models
Selected Annual costs per bed-acre for six nursery models.
land:
I-S1S5OM
D-S2S293/A
land
mprove-
menta
mecha-
nization .
contuln-
ef»-
pallcta
Modal 1 : Dutch traditional type I. OH Irr a. not rear
la
1$
$179
$2.447
$10.331
$2.950
Model 2: US traditional fTavtor). OH Ma
2a
2b
$359
$4913
$8.035
Model 3: Dutch type II. LinSL
3a
3b
$182
$2485
$15.390
$2.469
beds. OH
$2.950
Model 4: US traditional. OH irrfa runoff i
4a
4b
$362
$4,951
$8,781
$2.469
$6.780
notrecirci
$6,780
irria. recite
$6.780
follection-tr
$6.780
tabor
chemi-
cal*
Irrigation
water
*-$14(VM
b-$l2X/M
plant
shelter
total
annual
co»ts
utated 1 bed-acre/J. 29 production area acres.
$11.496
$5,152
$490
f*,203
$16,441
Tunnels
$53,819
$59,800
fated, 1 bed-acre/2. 59 production area acres.
$11,496
$5,152
$490
$4.203
$6.594
polvhse
$41,375
$49.642
ulated 1 bed-acre/1.31 production area acres..
$11,496
mt-recirct
$11.496
$2,911
$196
$1.681
lation. 1 wrf-acre/2.1
$2,911
$679
trtmt
$245
water
$679
trtmt
$2.102
water
$16,441
Tunnels
$56,346
$60.134
51 production-acres
$6,594
potyhse
$40,317
$46,763
Model 6.1 : Dutch type VI . Ovenutr tunnels, rocirculating ebb n flow, concrete floors, gantry robot.
1 pallet-acre oar 1. 16 Of eduction area acres.
5.1.4
5 1 b
$164
$2237
$20.741
$11.817
$6.780
$9.864
$6,323
$2,911
$147
S1.261
$16,441
tunnels
$75,188
$78,375
Model S.2: Dutch type VI. Heated convertible greenhouse p grow* cydx/yr), rocirculating ebb n flow,
concrete floors, oantrv robot. 1 pallet-acre oar 1. 18 production area acres.
S.Za
5.2.b
$164
$2237
Model 6.1: CIPPS, closed, Insulated pal
Automated oantrv robot, train conveyor,
6.1. a
6 1 b
$146
$1 992
$10.161
$5.176
$13.580
$9.864
$12.645
let production system
planting. 1 pallet-acre
$1.639
$18.053
$2,299
Model 6.2: CIPPS, closed, insulated pallet production system.
cyd«i/yr). Automated aantrv robot, train conveyor, planting. 1 p
6.2 a
6.2.b
$146
$1,992
$3,278
$18,053
$4.598
$5,823
$294
$2.522
$86.406
htdhse
$161.334
($80,667
per crop)
$165.635
($82.818
percroo)
Structureless potyfilm winter protection.
1.05 production area acres.
$1.030
$49
$420
$453
polyfim
Heated, convertible greenhouse
allet-acre/1.05 production area a<
$2,061
$98
$840
$86,406
htdhse
$39,006
$41.223
{2 growth
:res.
$129,977
($64,989
per crop)
$132.565
($66.283
per crop)
19
-------
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
In addition to container grown nursery and greenhouse plants, CIPS could be used
in the production of such high value crops as tomatoes and strawberries. In the U.S.,
thousands of acres of container and field grown crops - woody nursery plants,
horticulture greenhouse crops, and field grown tomatoes, for example - could'be
converted to CIPS. 80 percent or greater reduction in initial quantities of fertilizer
applied and elimination of discharge from the plant root matrix with the CIPS would
significantly reduce the environmental impact of agricultural crop production. While
CIPS was originally proposed to address challenges in container operations, Briggs
Nursery envisions that the concept can be applied to open field, intensive crop
production.
As the production area is completely covered in the CIPS, herbicides for weed
control may be eliminated. Nursery overwintering costs could be eliminated.
Reduction in greenhouse heating costs could approach 80 percent. More reliable
establishment and maintenance of beneficial organisms in the plant root zone is
expected due to the increased stability of the root zone environment in CIPS. The
reduction in temperature extremes can result in increased plant growth. Labor
demands and conditions will be more uniform year-round because of handling of
plants in groups in CIPS rather than moving individual containers. Plastic mulch,
containers, and overwintering covers, fumigation, and herbicides can be eliminated
with CIPS. Fertilizer and water use can be reduced and use-efficiency increased
The disposal or recycling of polyethylene plant containers (10,000 per acre of nursery
product on sales) would no longer be an issue as the GIPS is reusable with the
exception of the plant root pouch.
Barriers
Some questions regarding CIPS still must be addressed. These include:
overwintering and plant acclimation, limitations in the capillary irrigation system, and
general system engineering and design for commercial applications.
Because of the number of changes and the degree of each change, time will be the
most critical factor in gaining industry acceptance and adoption of CIPS. Long term
studies are required to establish the reliability of CIPS in commercial settings
20
-------
RECLAMATION FACILITY
FOR WASTE LITHOGRAPHIC INK
by
William Jacob
Ink Engineering Services
Columbus, OH 43209
ABSTRACT
This project proposed to establish and demonstrate the feasibility of a
reclamation facility for waste lithographic ink generated from the printing industry. Ink
produced by the reclamation facility will be formulated to meet or exceed the
standards of new ink, and is expected in increase waste ink usage from the current 5
percent up to approximately 80 percent. The project involves the establishment of a
closed-loop ink recovery and reuse arrangement with a select number of printers
located in Ohio. The arrangement will include documented transfer of waste ink from
the printer to the reclamation company, processing of the waste ink at the reclamation
facility, and return of the reprocessed ink to the printer for reuse on their web printing
process. The basic reclamation technology exists, however custom modifications
must be made and demonstrated to consistently produce an ink of high quality at a
cost that is competitive compared to the cost of purchasing new ink and disposing of
waste ink.
INTRODUCTION
PROJECT DESCRIPTION
Outline of Process
Today's high volume printers accumulate excess ink through the course of
normal daily operations. Whether the ink comes from overstock, the ink fountains of
the printing press, or are simply discontinued from further use, ink reclamation and
recycling is a viable alternative to disposal.
Inks which are likely to be recycled are HEATSET (for use on magazines),
NONHEAT NEWS (for use on newspapers), and FORMS INKS (for use on business
forms). All of these inks are used in large volumes. They do not contain any
chemical dryers which may cause "skinning" (drying) of the ink during the recycling
process.
This project involves the establishment of a closed-loop ink recovery and reuse
arrangement with a select group of printers in Ohio. Each printer's inks (all colors:) are
recycfed into black ink for their own use. All recycling is performed at the Ink
21
-------
Engineering Services'(IBS) Columbus, Ohio facility.
A schematic of the IES ink recycling process is shown in Figure 1.
Rgure 1. Ink Recycling Process
I.E.S. PROCESS SCHEMATIC
Input: Drum* of vacte ink
drum
drum
drum
Strainer (1/2 inch)
Strainer (1/4 inch)
Strainer ;(1/16 inch)
POMP
Storage Vessel fi
Strainer (1/16 inch)
Strainer (1/32 inch)
PUMP
Filter 0400 micron)
Filter (200 micron)
Filter (100 micron)
Filter (100 micron)
INPUT: Raw Materials
Storage Vessel #2
strainer (1/16 inch)
Strainer (1/32 inch)
PUMP
Filter (200 micron)
Filter (100 micron)
Filter (100 micron)
Filter ( 25 micron)
Output: Recycled Ink
nr
e Vessel f
drum
22
-------
Unique Product Features
All printing inks have very high quality requirements. Ink is produced to precise
tolerances so as to perform will on the printing press (runability) and to print well on
the paper (printability), The fineness of grind (particle size) on the ink must be no
larger than a tenth of a micron in thickness or unacceptable image reproduction will
result.
In waste ink, much larger particles, such as paper dust and other foreign
particles, have entered the ink. These particles must be filtered out to stringent levels
to make the ink usable. The cleaning procedures to produce recycled ink are far more
extensive than to produce virgin ink.
In Ink Engineering's recycling process, waste inks - not just black, but all colors
of ink - are cleaned and reformulated into black ink.
Product Advantages
Using recycled ink not only has an overall cost advantage, in many cases the
recycled black ink has quality advantages over the virgin ink which it replaces.
APPLICATION
Waste ink comes from a variety of sources and reasons in the printing facility.
Ink in the press can become contaminated from airborne particles, primarily paper
dust. Also, rather than risk contaminating fresh ink, any ink remaining in the press
fountain at the completion of a job is discarded. Inks can become overstocks from the
natural process of overestimating ink for a job, and from jobs which have been
canceled after the ink has been purchased.
Virtually 100 percent of the waste ink is recoverable. Only the contaminants,
primarily paper dust, will be trapped in the filter bags during the cleaning process and
removed. In most instances, 30 pounds of clogged filter bags are discarded per 3,000
pounds of processed ink (approximately 1 percent by weight).
The ratio of recycled ink to new materials is also quite high. IES uses additive
materials which enables them to formulate a significant portion of the waste ink into
recycled ink. The quantity of waste ink per batch depends upon the type of ink being
made. For example, for every 10 drums of waste ink sent for recycling, a printer
would receive:
• 12 drums of Nonheat News Ink or
14 drums of Heatset Uncoated Ink or
• 16 drums of Heatset Coated Ink
The waste inks should be of like chemistry to provide the best results. For
example, waste News Ink should be reformulated into recycled Nonheat News Ink,
preferably not Heatset Uncoated or Coated Ink. The quantity difference is made up of
23
-------
new materials, not virgin ink. The waste ink is reformulated with highly concentrated
pigment and varnish to produce the recycled product.
Cross Segment Uses
Such a recycling concept could be adapted to the paint industry, addressing the
unique formulations of the various types and applications of paints.
PROCEDURE
DEMONSTRATION
A sample of the printer's preferred black ink is obtained and a cost estimate is
made to recycle the ink by analyzing its chemical features. From this information, a
proposal is submitted to the printer.
Upon acceptance, a test batch of recycled ink is produced. Several drums of
waste ink are brought to IES and blended. Laboratory analysis is performed on the
blend to construct a sample formula. The blend is then cleaned and contaminants
removed. Virgin materials, such as carbon black pigment and varnish, are added
based on the Tab formula.
A major factor in the success of the demonstration is the ability to clean the waste
ink to a satisfactory state from which it may be reformulated into press-ready black
ink. Multiple straining and filtering steps bring the waste ink to a suitable level of
cleanliness, However, it is vital that contamination at the printers be kept to a
minimum. Severe contamination can lengthen processing time and increase the cost
of the recycling process.
Once the waste ink has been reprocessed, it must pass several quality control
procedures and tests in the lab to ensure its runability and printability characteristics.
These tests include:
• Tack - often referred to as the stickiness of the ink
• Viscosity - the body of the ink; the ink's resistance to flow
• Grind - particle size
• Color - even black ink must meet specifications for color; no tint of any other
color may be present
• Printability - appearance of the ink on coated and uncoated paper
Following additional processing, the final product is returned to the printer for a
press test When the recycled ink prints on the paper and everyone is satisfied with
its appearance and performance, only then will the printer be confident that ink
recycling is a viable alternative to disposal.
24
-------
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
During the project period, IES recovered 75,268 pounds of ink from 5 printers.
Press performance of recycled ink has met the specifications of the most demandjhg
pressrooms. Often the performance of the recycled black ink exceeds that of virgin
ink. Some virgin black inks may be considered "commodity" items and may not be of
the highest quality. The ink may be suitable for the application, but it may be possible
to construct a better quality ink from recycled materials. For example, the recycled
black ink may be comprised of non-commodity red, yellow, and blue inks that contain
some amounts of higher grade ingredients. The resulting recycled black ink will thus
exhibit some of the improved properties of these ingredients (e.g., runability, density).
content
70 percent; .. .
cost increases because of the high quality materials used, by raising the salvage
content, less raw material is required.
In 1991, IES received the (Ohio) Governor's Award for Outstanding Achievement in
Pollution Prevention "for developing an innovative process to recycle a manufacturing
waste into a new product, thereby offering a viable alternative to disposal."
Product Quality Variance
Press performance of the recycled ink has been excellent To maintain this
standard, it is essential that, batch to batch, the ink be of consistent quality. This is
complex, especially considering the blend of recycled ink is comprised of different
colors each time. Extensive lab tests ensure a consistent, high level of performance
results.
Conditions That Impact Performance
A key element to the success of ink recycling is that printers segregate their waste
streams. Standard lithographic paste inks are not currently considered hazardous.
But printers must not mix waste oils and grease, flammable materials, or trash with the
waste inks which will negatively impact the recycling process, or worse, contaminate
the ink, rendering it hazardous and ineligible for the IES recycling program.
/
Cost Benefit Analysis
The examples in Table 1 and Table 2 suggest that a printer must buy new ink for
normal operations, and the need to dispose of 2,200 pounds of waste ink is
necessary.
25
-------
Table 1. Cost Comparison of Incineration and Recycling of Ink for a Large
Columbus, Ohio Inserts Printer
Action
Cost to purchase new ink
Cost to bum waste ink
Transport cost to incinerator
Transport cost to IES (printer
delivers waste ink to IES)
Freight cost of recycled ink to
user (printer retrieves recycled ink
from IES)
Total cost
Total cost per pound of ink
Real savings
Pounds
3,000
2,200
2,200
2,200
3,000
1
Kv^'irgfafiS^"^
I/Pound
1.25
0.61
0.07
0
0
Extended
$
3,750
1,342
154
0
0
5,246
1.75
2,396
"
$/Pound
0.95
0
0
0
0
Extended
$
2,850
0
0
0
0
2,850
0.95
Table 2. Cost Comparison of Incineration and Recycling of Ink for a Large Iowa
Inserts Printer
Action
Cost to purchase new ink
Cost to bum waste ink
Transport cost to incinerator
Transport cost to IES
Freight cost of recycled ink to
user
Total cost
Total cost per pound of ink
Real savings
Pounds
3,000
2,200
2,200
2,200
3,000
1
: ^ "* &>4££fsifT. £•"• '•'^^^C&x. ^ v£"'!§v^v
(t&VjMfajMtitK'' **'
$/Pound
1.50
0.61
0.07
0
0
Extended
$
4,500
1,3426
154
0
0
5,996
2.00
592
$/Pound
1.68
0
0
0.07
0.07
Extended
$
5,040
0
0
-154
210,
5,404
1.80
26
-------
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
In support of the Pollution Prevention By and For Small Business Grant Program,
the National Environmental Technology Applications Corporation (NETAC) conducted
a telephone market survey for IES to characterize the need for waste ink reclamation
services in the lithographic printing markets surrounding Atlanta, Georgia and Chicago,
Illinois.
NETAC estimates that 65 percent of the lithographic printers in the above market
areas dispose of waste lithographic ink; 23 percent reclaim waste ink; and 12% return
waste ink to their contracted ink suppliers.
In the Atlanta area, NETAC estimates that 267,000 pounds of waste lithographic
ink is disposed annually by printers and 1,748,000 pounds of waste lithographic ink
disposed each year by Chicago printers.
Even with the current trend toward minimizing waste lithographic ink by printers, a
great deal of ink is still disposed.
IES returns all reformulated waste lithographic ink to the same customer from
which it originated as black lithographic ink. This reformulated product is typically 80
percent waste ink. As a result, each customer must have a need for black ink that
exceeds its generation of waste ink by at least 25 percent.
Survey participants in Atlanta and Chicago indicate that price and reformulated ink
quality are key considerations when evaluating the potential usefulness of an ink
reclamation process.
IES has already successfully taken their recycling service to the marketplace and is
still working to gain industry acceptance. Through education and demonstration of
recycled ink quality, IES hopes to make ink recycling as common as paper recycling.
27
-------
TOTAL LUBRICANT CONTROL SYSTEM
FOR RECYCLING USED LUBRICANTS
by
Stephen McCollister
McCollister and Company
Council Bluffs, IA 51502
ABSTRACT
This project proposed to establish and demonstrate the Total Lubricant Control
(TLC) system for recycling used lubricants. Expanded voluntary used oil recycling has
been hindered as a result of recent increased scrutiny and concern for quality control
to protect against improper mixing of other wastes (e.g., chlorinated solvents) with
used oil that is to recycled or otherwise beneficially used. Unique aspects of this
project center on the establishment of a systematic approach to the collection,
consolidation, testing, and reuse/recycling of used lubricants that maintains superior
control, and in turn ensures ample supply of high quality feedstock for used oil re-
refiners and other beneficial users. A successful project which demonstrates that
used lubricants can be economically recycled under strict environmental controls will
go a long way towards promoting nationwide acceptance of environmentally sound
recycling practices for used oil.
INTRODUCTION
PROJECT DESCRIPTION
McCollister and Company's Total Lubricant Control (TLC) provides a systematic
approach to the collection, consolidation, testing, and recycling of used lubricants.
Voluntary used oil recycling has been hindered as a result of increased scrutiny and
concern for quality control to protect against improper mixing of oil with other wastes
The TLC approach provides McCollister and Company with control over the lubricants
which ensures ample supply of high quality feedstock for used oil re-refiners and other
beneficial reusers.
Outline of Process
A strength of the TLC plan is its ability to be measured and evaluated. The
quantities of used lubricants that are recycled or reused can be documented to the
gallon.
This control stems from a comprehensive collection system which includes:
1. Source Control - correct management of the used lubricants by the
generator at the generator's facility.
28
-------
2. Collection - collecting from the generator, transporting, and testing of the
lubricants.
3. Disposition - marketing the used lubricants to beneficial reusers and
recyclers.
4. Recordkeeping - tracking of used lubricants according to the preceding
points.
Unique Process Features
The systematic nature of the TLC plan minimizes contamination concerns and
the inconsistencies often associated with used oil collection.
APPLICATION
The TLC system has eliminated the uncontrolled disposal of waste oil by over
40 vendors.
The primary customer for McCollister's demonstration is United Parcel Service
(UPS). The waste lubricants received are a mix of engine oils; transmission fluids,
gear oils, and hydraulic fluids. UPS's prior waste lubricant management system was
through numerous contractors, thus offering little control over the disposition of the
lubricants.
The collected waste oil is destined to be "recovered fuel." It is primarily crank
case oil from diesel engines and often contains unburned diesel fuel and carbon which
enhances combustion in an industrial boiler. When properly blended with #5 heating
oil, it lowers the pour point of the fuel, enhances combustion, and increases the BTU
value of the fuel for the boiler.
The re-refining market for waste oils is very small. Demand for re-refined oil by
commercial entities and the public is limited.
Cross Segment Uses
The TLC plan could be adapted for the collection and management of other
material (e.g., paint or solvents) which may not be recovered for reuse or recycling. A
systematic collection plan encourages the generator to revise their waste handling
practices towards waste segregation and minimization.
PROCEDURE
DEMONSTRATION
McCollister and Company originally entered into an agreement with UPS to
29
-------
manage waste oils at operations in Missouri and Iowa. Operations in Kansas,
Nebraska, Minnesota, and South Dakota were soon added.
McCollister modified an existing waste oil transport vehicle to accommodate the
simultaneous delivery of new lubricants and the collection of waste oil. It was
necessary to guarantee that contamination of new product and waste product did not
occur. The resulting vehicle was compartmentalized with dual pumps, meters, hoses,
and assemblies. Trial and error resulted in refinements to strainer size, pumping
speeds, suction pipes, and suction hoses. Refinement of equipment continued
throughout the demonstration.
The modified transport has four compartments: two .2,500 gallon
compartments; one 2,200 gallon compartment; and one 1,300 gallon compartment.
The 2,200 gallon compartment is dedicated to waste oil. The common manifold in the
tank area of the truck was removed so each compartment could be modified to have
its own segregated load/unload valve and adaptor.
To fully understand their waste oil situation, McCollister and Company visited
UPS district operations in Sioux Falls, South Dakota; Minneapolis, Minnesota; Des
Moines, Iowa; Kansas City, Kansas; and Omaha, Nebraska. Through discussions with
the regional managers, McCollister learned the following:
1. UPS in the west region, which comprises nine states in the midwest,
utilizes over 40 different contractors to collect waste oil.
2. A systematic approach to waste oil collection does not exist at UPS.
3. Some UPS locations have EPA generator permits. With some of the
automotive materials.utilized, and under certain state jurisdictions, EPA
generator permits are required.
4. The issue of third party liability for improper disposal is of great concern to
UPS. Thus a systematic program for waste oil management is of great
interest to UPS.
UPS designed a questionnaire for its service centers in the west region to
better understand and document waste lubricant handling procedures and needs.
McCollister compiled the data from the questionnaires and developed a routing
schedule to service these locations based on monthly usages and volumes.
A pre-testing program for each site was performed. This identified any
contamination problems that could then be remedied with the cooperation of site
management. Waste lubricant testing was fairly extensive at some sites and included
analysis for total halogens, flash point, water content, and heavy metals. It was also
found that some waste oil collection tanks were outside, most were not locked, and
some were open to collect rain water.
Based on this information, McCollister designed a route which served 25
facilities in 6 states, with tanks ranging from 200-3,000 gallons. To reconcile the
varying requirements in the states served, McCollister established procedures with the
regional manager to standardize UPS procedures. Also, Missouri required manifesting
30
-------
the used oil. McCollister used Missouri's manifest as a model for use in other states
to standardize recordkeeping.
Collected oil was delivered to a fuel blending facility which performed further
tests on the oil to determine its suitability for use as a fuel. No oil was found to
contain contaminant levels which would render it hazardous, and thus inappropriate for
this end-use.
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
After one full year of waste/used oil collection from UPS locations in 5 states,
the following data have been accumulated as shown in Table 1.
Table 1. Waste/Used Oil Collection from UPS Locations
''','"'4,' 'I'-l", -'f 'f^f-'-iff '& ™% ,^
.|&~ 11^ ./*«-;»....
Missouri
Iowa
Kansas
Minnesota
Nebraska
^^i«S&iv^
40,891
26,838
30,264
30,502
15,401
^a^ori^^RW>vlr«d
17,145
10,980
22,337
23,584
7,554
~-'&M^«krH
41.93%
40.91%
73.81%
77.32%
49.05%
Data Analysis
1. Total sales of new petroleum products to UPS was 143,896 gallons.
2. Total used oil collected from UPS was 81,600 gallons. The company
believes that the collection of waste lubricants is most efficient when done
at the time that new product is delivered to the customer.
3. The 56.7% overall recovery rate is slightly lower than expected due to the
delayed participation of several of the larger UPS centers until the second
quarter of 1992. All sites produced the same grade of.used oil.
4. The national average for recovery from new oil to waste oil is 60-65
percent, which is McCollister and Company's goal for 1993.
5. The used oil is delivered directly from McCollister's transport vehicle to a
registered blender of heavy oils for reformulation into boiler fuels for an
31
-------
asphalt plant.
Product Quality Variance/Conditions That Impact Performance
The quality of waste oil is variable. While McCollister could prevent
contamination through training and control, the amount of bilge, sediment, and water is
variable according to location, weather, types of vehicles serviced, and local
management. Quality of the waste oil is controlled, and contamination is prevented by
limiting the number of customers (to a few large volume customers) and establishing
management procedures for handling the used oil. Oil was primarily tested for
halogens; tests for PCBs and dioxin contamination were unnecessary because UPS
only operates a fleet of vehicles and would not be recycling oil from potential PCB
sources such as transformers. If any problems are discovered in any batch of used
oil, McCollister's recordkeeping system can trace the load back to the source.
In the UPS program, no waste oil was contaminated with hazardous
constituents or materials that made it unusable. While rocks, metal washers, dirt, and
especially water in the oil storage tanks can cause difficulty in handling the waste oil,
they do not render the batch "off spec" or hazardous. The value of the batch is simply
reduced.
In additional to the used oil collection, McCollister and Company has included
the collection and recycling of used oil filters. Many large lube oil customers expect
the waste oil vendor to collect filters, as well as the waste oil. The filters are drained
and crushed prior to being hauled to a steel smelting operation in eastern Nebraska to
be recycled into new steel products. Before McCollister and Company initiated the
collection of oil filters, state laws and regulations regarding used oil filters were
thoroughly researched. Many state regulations can be inconsistent and complex.
Minnesota, for example, considers crushed filters a hazardous waste, but not the oil.
Missouri, conversely, considers waste oil hazardous, but not the filters.
Cost/Benefit Analysis
While the technology for reuse and recycling is readily available, or at least
known, the major limitation beneficial reuse of waste lubricants is cost. McCollister's
collection cost (April 1992) for of waste lubricants for fuel blending is over $0.33 per
gallon; this includes payment to the customer, transportation, supplies, testing, delivery
to the fuel blender, ana administration.
Collecting the waste lubricants for re-refining adds $0.15 to the above costs.
This covers the additional handling steps of storage, water separation, and
transportation to a re-refiner.
New virgin base oils in the quality and technical range of re-refined base oils
are commonly marketed for under $1.10 per gallon. Assuming waste feedstock is
delivered to a refiner for $0.48 per gallon (which does not include overhead and
profit), the refiner would need to process and sell the refined oil for under $0.62 per
gallon. Thus the economics for re-refining are marginal.
32
-------
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
According to surveys of the lubricant market hundreds of millions of gallons of
lubricants are sold in the United States each year. Much of this oil is improperly
disposed, making the potential for waste oil recovery significant
As a fuel, used lubricating oil can substitute for virgin products safely and
economically.
An organized systematic used oil collection program ensures the proper
disposition of this material and helps to enhance the market for used lubricants.
Limitations
As previously discussed, cost is a major limiting factor in used oil collection,
especially for the re-refining market. Presently, insufficient demand for a re-refined
lubricating product has kept the market quite small. Trust and acceptance of a
re-refined product, and modification to industry and government specifications to
permit the use of re-refined oil must occur before the bulk of waste oil utilization shifts
from a fuel end-use to a re-refining end-use.
33
-------
THE AGITAIR DISPENSER AS A SUBSTITUTE
FOR HOUSEHOLD AEROSOL DISPENSERS
by
John V, Mizzr
Omniffc International Limited
Poughkeepsie, NY 12603
ABSTRACT
This project involved the C9nstruction of 5 demonstration prototypes of an
AGITAIR dispenser, an aerosol dispenser which used compressed air as the
propellant. The adoption of this dispenser as a substitute for ordinary household
aerosols would eliminate the use of chemical propellants such as chlorofluorocarbons
or hydrocarbons, and possibly convert the aerosol product market into one that uses at
recyclable product module or a nondisposable refillable dispenser thereby eliminatina
the "throw away" aerosol can. AGITAIR uses air as the propellant, which is generated
by the natural act of shaking the dispenser a few times before using Air is
compressed with a small pump located inside the unit. The project involved detailed
design improvements or earlier prototype models, fabrication of new prototypes usina
improved materials, testing, and evaluation. XH »»•«
INTRODUCTION
PROJECT DESCRIPTION
The AGITAIR container is a self-pressurizing aerosol dispenser that uses air as
the propellant. This dispenser technology has a built-in, inertia-coupled air
compressor that is activated simply by shaking the unit. The propeilant is replenished
with every use by following the familiar regimen of "shake before using." During this
project, five working models of this technology were constructed. Each prototype was
different to illustrate various applications of this technology. The objective was to
demonstrate operation, not to produce detailed manufacturing prototypes.
Unique Product Features and Advantages
AGITAIR can be configured as a reusable/refillable dispenser. It also can be
incorporated into recyclable, one-use product modules that couple to a reusable
activator (pump) module. Unlike manual pump sprayers that provide only an
intermittent "burst" spray, AGITAIR provides a long duration, steady spray. The
AGITAIR container can be "recharged" prior to use by a quick, one-handed shake.
AGITAIR has several advantages over chemically propelled products The
principal advantage is solid waste reduction by virtue of refillability or recycling of the
34
-------
metal or plastic modules. Another advantage is economy: savings may be realized in
product containers (thinner walls, lower pressure operation); no propellant use/cost;
low filling costs (ambient condition filling); and insurance costs associated with filling,
warehousing, and transporting. In addition, AGITAIR may be used in cold
environments unlikeja conventional aerosol can, which stored in cold surroundings
may fail because of temperature-dependent vapor pressure depression.
Product Drawings
Figure 1 shows a side-coupled, two module AGITAIR dispenser using a piston
compressor. (Another model of this type using a bellows compressor has also been
built.)
Figure 1. Side-coupled AGITAIR With Piston Compressor
;
35
-------
Figure 2 shows a cross section of the "metal model," which used a piston and
cylinder compressor where the cylinder is part of the recyclable product container. In
this model, the actual liquid product is part of the activating weight assembly to
achieve higher pressure capability without excessive additional weight. Thus, while
the product module is full, the increased pressure that is generated when the
container is shaken creates a reserve of compression, which reduces the need for
shaking when the product level is low. The objective of this model is to illustrate the
adaptability of the AGITAIR Aerosol technology to conventional container standards.
Rgure 2. Metal Model - Piston Version
36
-------
Figure 3 shows a cross section of a piston and cylinder pump AGITAIR
dispenser. In this design for a reusable/refillable dispenser, a plastic housing contains
the product and the pump mechanism, which is attached to the screw-on cap
containing the valve and nozzle.
Figure 3. Refillable AGITAIR With Piston Compressor
37
-------
APPLICATION
Products Replaced
AGITAIR is a replacement for chemically propelled aerosols as well as manual
pump sprayers.
Because of the size constraints imposed by the driving weight and compressor
assembly, the smallest practical size limit for the container, would be approximately 2
inches in diameter and 4 inches high with about one-half the volume devoted to a
liquid product. At the other end of the scale, a dispenser with about 16 ounces of
liquid product would be the practical volume limit, since the entire container must be
shaken to pressurize.
Wastes Prevented
Standard aerosol dispensers are a source of solid waste. Because of their
pressurized propellants, they are not always accepted for recycling. AGITAIR can
minimize sofid waste in two ways:
• As a refillable container
• As a side-by-side, two-module dispenser with sectionattached to a recyclable or
factory filled product module
Since AGITA9R uses air as a propellant, it eliminated the use of chemical propellants.,
Cross Segment Uses
The AGITAIR system is appropriate for use in both household and industrial
applications. AGITAIR can tolerate a wide range of temperatures, as the temperature
tolerance depends on the properties of the liquid contents. The lower temperature
limits is a function of the product's freezing point, whereas typical aerosol containers
do not function well below 30°F if using liquified hydrocarbon propellants. The
AGITAIR's upper temperature limits also depend on the properties of the contents.
Pressure in the AGITAIR will not rise with temperature, and the container may safely
be punctured. A traditional aerosol can's upper temperature limits are approximately
130°F.
The AGITAIR has a long storage life. Leakage of propellant is not an issue, as
loss of pressure in the container can easily be restored by shaking the container.
The side-by-side dispenser offers convenience in "compressor sharing" because
the compressor module may be easily removed from one product module and
snapped onto another. Such an application is useful for certain classes of products
such as paints or cleaners where a compressor module would serve numerous
product modules. As each product module has its own discharge valve and nozzle,
no contamination occurs. Different classes of product modules stored in proximity
could also be accommodated in this way.
38
-------
PROCEDURE
DEMONSTRATION
The original intent of the demonstration was to build five identical working models
using tapered bellows as compressor elements. As the project progressed, this
objective evolved into the fabrication of three models ~ the side-coupled version, the
metal model, and the plastic model - with bellows or piston and cylinder elements.
Maintenance of pressure and spray quality were indications of success in the
demonstration. In all trials, water was used as the "liquid product" and was dispensed
from the models. Commercially available spray nozzles were utilized in all cases. To
maximize spray dispersion, custom nozzles could be designed for specific liquid
products.
Compressor Development
Previous limited success with a dip-molded vinyl bellows led to plans for a rubber-
transfer-molded bellows. The geometry of the original design was discovered to be
incompatible with the bellows manufacturing technique, but a bonded two-part bellows
or an injection molded-bellows would be suitable for this application. With the cost of
injection molding, the limited budget for conducting the project, and uncertainties over
the performance of a liquid casted bellows, development was redirected to a piston
ancl cylinder compressor design while also pursuing alternate bellows fabrication
techniques.
Metal Model
Using a piston and cylinder compressor, the first metal model was built using a
commercially available 10.5 ounce aluminum aerosol can housing and an inner 6-
ounce steel juice can as the product container. The aluminum aerosol can was cut
one-third from the bottom and a fabricated twist closure collar was applied to each
section for ease in opening the can. The juice can containing an integral compressor
cylinder was then slipped over a piston that had been attached to the bottom of the
housing. An outlet hose was attached to the top of the product container, facilitating
the liquid connection to the dispensing valve.
This model performed well once initial problems were solved. For example, while
testing pump performance by manually pumping the product container (instead of
shaking the container), higher than normal pressures resulted, causing the cylinder
head to separate from the check valve housing by rupturing the solder joint. When
the product container was disassembled to resolder all parts, the inside of the product
container was found to have several rust spots. The inside and outside of the
container was then coated with rust-inhibiting primer and paint. In addition, a
bottle-type valve on a removable fixture was fitted to the top of the metal can housing
to more securely fasten the hose from the pressurized product chamber.
While the metal model worked well and retained pressure for several days, a very
slow leak from the outlet check valve was discovered. Rubber "duck bill" check valves
were successfully substituted.
39
-------
Plastic Model
A second model was constructed from a commercially available non-aerosol
plastic package, which utilized the product container, nozzle, closure, and dip tube A
housing containing a "shake activated" compressor was added to the unit. The
housing was designed to accommodate either a piston and cylinder or a bellows air
compressor that would simply be screwed onto the bottom of the housing.
A silicone bellows version was initially constructed in the plastic model. At low
pressures, the bellow's performance indicated the need for reinforcing rings. While
the bellows withstood adequate pressures of 15 psig, the nylon rings ultimately
interfered with pump operation. Subsequent trials with silicone and dip-molded
bellows were also unsuccessful as these bellows developed leaks or could not
withstand the pressures generated.
An additional problem occurred in the form of a leaky check valve. The rubber
duck bill check valves were again substituted with good results.
Omnific elected to shift the focus to a piston and cylinder application for the plastic
model as this technology had been successful in the metal model.
A piston version with a duck bill check valve was fabricated and installed in the
plastic model. The weight to activate the piston was a piece of brass and activation
weight did not include the weight of the inner product container or its contents This
version performed well.
As bellows research progressed, this version was again attempted. The plastic
model with a dip-molded and reinforced bellows plus duck bill check valves was
unsuccessful, as the bellows collapsed on intake and tore. Another dip-molded
bellows without internal metal rings was installed along with a new low-restriction ball
check valve. This valve was added after realizing the bellows did not produce enough
vacuum upon extension to operate the duck bills. The performance of this version
equalled that of the piston and cylinder plastic model.
Side-Coupled Model
The side-coupled model with a piston and cylinder outperformed the bellows
version. Pressure and spray quality were excellent.
Again, difficulties in design and construction resulted in bellows failures. In this
instance, the silicone bellows was abraded by the brass wire reinforcing rings and
developed leaks. Omnific believes that an injection molded bellows would address
many present limitations of the bellows; however, tooling costs preclude this approach
at this time. K
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
In all three AGITAIR models, the piston and cylinder versions outperformed the
4Q
-------
bellows versions, as bellows design and fabrication have not been perfected. All
models have worked with varying degrees of success. At the conclusion of the
project, the bellows version of the side-coupled model was not operational, as the
bellows had developed a puncture. Such a problem was recurrent with the various
bellows designs and materials tested.
Product Quality Variance
At the time of publication, best performance was achieved by the metal model. All
piston and cylinder models outperformed the bellows models.
Conditions That Impact Performance
The fabrication of custom bellows for this application has proven more difficult
than anticipated. During the project, the bellows versions suffered from inlet check
valve leakage and inlet restrictions. (Since the end of the project period, limitations in
inlet check valve design have been analyzed, and a special design for use with
bellows has been defined.) Budget constraints also limited design and materials
selection to one design for liquid casting. Omnific believes injection molding of
thermoplastics will yield an appropriate bellows model with a greater design flexibility
than the piston model. While Omnific believes a bellows component would have
certain performance advantages over cylinder and piston models in terms of reduced
friction losses, better space utilization, quicker pressure build-up, and higher terminal
pressure, design and materials engineering will require additional research.
Actual spray performance was affected by the nozzle. Commercially available
nozzles were utilized throughout the project. A nozzle designed specifically for the
characteristics of the product being dispensed and the pressures generated would
enhance the performance of the dispenser.
Tabulation of Data
All trials were conducted using manual shaking of the dispensers. Variations in
how vigorously the dispensers were shaken would affect pressure results. A
programmable shake table with repeatable stroke frequency and displacement should
be used for such testing, but was not available for the project.
The metal model is the best performer by virtue of the high pressure achieved (18
psig or 124 kPa) by combination of the heavy driving weight (piston weight plus liquid
product weight) relative to piston diameter.
The two models built into the plastic, non-aerosol dispenser have the poorest
performance in terms of spray dispersion, as they only generate a pressure of about 8
psig (55 kPa) and the nozzle is designed for approximately twice that pressure.
The two side-coupled models have a median performance generating pressure of
approximately 11 psig (76 kPa).
These performance parameters have been developed in a simple adiabatic
compression model; performance testing verifies model validity.
41
-------
Cost/Benefit Analysis
An accurate product cost analysis of the various AGITAIR models has not been
performed, as key full-scale manufacturing designs have not been investigated^
However, from the Omnific's general knowledge with similar devices, a pump section
would be priced from $0.20-0.50. The containers or product modules should be
comparable in cost to other low pressure, high volume containers. Once designed,
custom nozzle variations should be no more costly than the standard aerosol valves
and nozzles used in the project. Since the pump section is reusable, a refillable
AGITAIR dispenser would likely have a higher initial cost than a comparable
disposable aerosol package, but would ultimately be less expensive on a product life
basis.
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
The AGITAIR container is still in the model development stage. The feasibility of
the technology has been successfully demonstrated and is ready for refinements for
commercialization. The commercially manufactured version will be designed to
minimize solid waste in production.
The aerosol container market is significant The current aerosol can market is
estimated to be 3.6 billion units annually.
In addition, the AGITAIR technology eliminates the release of chemical propellents
into the atmosphere, as air is the propellant
Limitations
The AGITAIR technology is too expensive as a disposable product. That is, a
complete AGITAIR dispenser would be somewhat more expensive than an ordinary
aerosol container if pump cost is included.
The maximum practical pressure achievable is approximately 20 psig (138 kPa).
Some products may oxidize or otherwise deteriorate if stored in contact with air under
pressure.
The AGITAIR system is designed for reuse - either the entire dispenser can be
reused by refilling, or by reusing the pump in the case of the side-coupled or internal
module types. The overall lifetime cost of the AGITAIR dispenser is therefor© quit©
low.
A pressure of 10-20 psig (69-138 kPa) should be adequate to provide a high
quality spray for liquids or to generate foams. A separating membrane may be used
to isolate a product from contact with the air propellant to prevent oxidation or
deterioration of the product.
42
-------
RECYCLING VALUABLE COMPONENTS
FROM USED TELEVISION CABLE
by
Joe Kay
PAC Recycling
Maryville, TN 37804
ABSTRACT
A mechanical process to separate valuable components from used television
cable was researched and developed. The cable television industry is now beginning
to replace thousands of miles of television cable installed over the past two decades.
This type of cable is a composite os aluminum, plastic, and copper which, when
separated, are valuable materials that can be recycled and reused. The aluminum-
plastic bond inherent with this cable is very strong and requires mechanical processing
to separate the components. The results of initial research to identify processing
steps have been promising. This project explored innovative approaches to machine
and process design in order to develop a continuous separation process.
INTRODUCTION
PROJECT DESCRIPTION
PAC Recycling has devised an innovative mechanical process to separate the
components of CATV cable - the type of cable strung from one utility pole to another.
The cable television industry replaces 200-400 miles of cable every 3-5 years. The
waste cable is typically landrilled, however handling of the cable at the landfill can be
difficult. Waste cable is not usually re-rolled onto a spool and is delivered to the
landfill in tangled sections. This cable in this condition occupies additional landfill
space. Also, during landfill compaction, the cable can easily become entangled in the
tracks of the bulldozers and other equipment
Television cable is a "bundle" of components comprised of:
1. Support Cable - a 1/i inch diameter galvanized steel cable which carries the
load or weight of the CATV cable,
2. CATV Cable - the main component targeted for recycling, the cable is
made up of an outer aluminum sheath over plastic dielectric and an
aluminum core. (Figure 1)
3. Lashing Wire - a small diameter wire that binds the CATV cable to the
support cable.
43
-------
4. Miscellaneous Connectors and Fasteners
In order to effectively recycle the CAW cable, it must be separated into its
components. The bundle is untangled and straightened, the CAW cable is isolated
and this cable is mechanically separated into its individual elements.
Rgure 1. Cross Section of CAW Cable
CROSS SECTION THRU A
CATV CABLE SCALED/
OUTER ALUMINUM
SHEATH,
* ,^>-^->^Kj^^vi-MlHj-< H>o^^^v/y
^m^H^s^yy^ess^^
Y^-^^^^-^^K^H^^Jr'./
X/x-<_X_w W w^-j"~w~Ww\_
44
-------
The greatest proportion of this project centers on steps 3, 4, and 5 as outlined in
Figure 2.
Figure 2. Process Flow Diagram
NO. 2
NO. 1 + 1
+ +
LOCATE AND ACQUIRE ! TRANSPORT THE CABLE
CABLE WHICH IS BEING + -> TO PLACE OF PROCESSING + >
REPLACED BY CATV J
COMPANIES !
+ »-»—• — -»..-•»«« — _»•—«•—•—• — —• — —•_«-»^ A _ . « _...._.,...._ «»•»••«.•• «*____.»-• A
NO. 4
NO. 3 + +
+ + INITIAL PROCESS OF CATV |
-->! SEPARATE THE "BUNDLE" +-> CABLE - SEPARATE AND CHOP +->
i INTO THE COMPONENTS ! THE OUTER ALUMINUM SHEATH |
+ __ . + PROM THE INNER COMPONENTS !
NO. 5
+ «««»«^«^««av«» * 1&f^ C
; 1- MO . D
SECONDARY PROCESS OF j + : +
> CATV CABLE - SEPARATE + >! WIND-UP CORE INTO A +—>
THE PLASTIC DIELECTRIC! ! COMPACT PACKAGE J
FROM THE ALUMINUM CORE i + +
NO. 7
>! SHRED PLASTIC INTO A !
i SELLABLE FORM !
45
-------
APPLICATION
The CATV cable is available for reclamation in two forms:
1. Old cable which is being replaced.
2. Short ends which are left on new spools of cable.
Labor to prepare the "short ends" for recycling is minimal However, the old
cable which has been removed from the utility poles is bound and tangled with the
galvanized steel support cable and lashing wire, and significant processing time is
required to prepare the old cable for separation into its components.
Wastes Prevented
CATV cable is a composite before processing and is virtually worthless in this
form. Separating the cable into recyclable components yields "raw materials" for
remanufacturing which must be as free of contamination as possible.
The application for each component of the used cable are as follows:
• The galvanized stranded support cable has slight value for scrap purposes only.
The galvanized coating makes this an undesirable metal for remelt Resale
value is small, and at best, freight costs for shipping the material to a recycler
may be recovered. While the economics are poor, the cable can be recycled
instead of landfilled.
• The lashing wire is stainless steel and is more desirable for recycling. This
component is clean and pure, and lends well to remelt. The total weight of the
wire is small - less than 2 percent when compared to the whole cable. Again,
although income from the sale of the wire is low, the wire is being recycled
instead of landfilled.
• The CATV cable is the major recyclable component of the cable "bundle". The
cable sheath is high grade aluminum which is desirable for remelt. The plastic
dielectric is a recyclable thermoplastic. The aluminum core may also be
reclaimed.
Market Values
The market values (spring 1992) of the components are:
• Lashing Wire - $.10-. 12 per pound. This is less than half the present value of
stainless steel.
• Aluminum Sheath - $.40-.42 per pound. Approximately 12 feet of 3/4 inch
cable produces 1 pound of aluminum. With the separating machine running at
75% capacity, approximately 1 pound per minute can be obtained.
• Plastic Dielectric - $.06-.08 per pound.
46
-------
• Aluminum Core - $.24-.25 per pound. This value is approximately 60 percent of
the aluminum sheath because the core is not only copper clad which renders it
less pure, it also has a small amount of plastic on the outside after separation
which lowers the quality of the aluminum.
• Galvanized Steel Support Cable - This component is almost worthless as its
galvanized coating makes it undesirable for remelt. However, the $.01-.02 per
pound price may pay for freight.
Cross Segment Uses
Other utilities, such as telecommunications and electric, use cable for their
transmissions. These cables are usually plastic or rubber coated covering multiple
wires. The composition of the cable dictates recycling potential and monetary worth.
PROCEDURE
DEMONSTRATION
PAC Recycling mailed questionnaires t6 75 cable television companies in easit and
central Tennessee requesting infqrmatidn on their disposal methods for discarded
cable. Fifteen companies returned the questionnaires. Responses indicated that 47
percent of the companies landfill their cable, 40 percent sell it, and 13 percent dispose
of the cable in other ways.
Additional research indicated that most cable is discarded during system rebuilds
versus day-to-day maintenance.
In the first phase of technology development, PAC developed a prototype of a
"Scrap Chopper" with 4 main components.
1. Guide Roller and Slitter - The cable enters the Chopper through a four jaw
scroll chuck which is fitted with guide rollers and slitting knives. The hook
shaped knives slit each side of the cable. The chuck may be adjusted to
accommodate diameter of the cable which is being processed.
2. Pull Rollers and Separators - Two pairs of rollers grip the split aluminum
sheath, peeling it from the plastic and core. The rollers are made from
hardened tool steel with 64 pitch straight knurls on the outside for enhanced
gripping and pulling of the sheath.
3. Sheath Chopper - As the sheath exits the pull rollers, it is flattened and
chopped into 6 inch pieces by rotating knives cutting against a stationary knife.
The chopped pieces fall into a storage container below the machine.
4. Frame - Components 1-3 are bolted to a rectangular welded tube frame.
electric motor and gear box are mounted to the top of this unit.
An
47
-------
In the second phase of development, PAC designed a Pulling Unit to pull the
cable through the Chopper, separating the plastic dielectric from the center core and
directing the plastic to an off-line grinder. Two specially developed rollers grip the
core and crush the plastic which then easily separates from the core. See Figure 3.
Rgure 3. Scrap Chopper.Components
SCROLLING TYPE
LATHE CHUCK
TO NEXT
MACHINE
INCOMING CABLE
GUIDE ROLLER ..
KNirE TO SLIT SHEATH
SDHEATH HALF
STEEL ROLLER
STATIONARY KN*FE
ROTATING KNIVES
PLASTIC JHELECTmC
AND COW
CHOPPED SHEATH
10 .MACHINE STAND
;U SIDE PLOTE
48
-------
Manual operational trials of the Chopper tested cutting ability, drive mounting and
chain configuration, and sheath slitting knives. These trials led to the following design
changes:
1. The slitting knives were redesigned, as forces applied to the sheath during
slitting resulted in breakage of the sheath. The original knives were designed
like miniature "pizza cutters". This design required high pressure on the knives
and rollers to penetrate the sheath, thus causing the breakage. A hook design,
similar to a seam ripper, allowed reduction of tension in the guide rollers, and
the sheath could then sliced with much less pulling force.
2. The original gear box mount deflected at the time of the cut causing extreme
vibration in the unit. A redesigned, heavy duty mount and a change of the gear
box drive chain from one to two chains solveci the problem.
3. Guides were placed between the flattening rolls and the cut-off knives to
eliminate a "wrapping around" of the sheath and properly guide it to the cut-off
knives.
4. A lead-in guide was installed to straighten and center the cable as it was fed
into the slitting blades of the Chopper.
5. The gears on the cut-off knives were changed to allow the knives to run faster
than the linear speed of the sheath. Prior to this change, the sheath buckled
which jammed to machine.
6. The main control panel was modified so the Chopper could be reversed or
"paused" to permit threading and startup.
7. A swing-into-positton hand winch and pulley mechanism was added to thread
the cable through the slitter.
RESULTS AND DISCUSSION
PERFORMANCE SUMMARY
The "Chopper" successfully separates the components of the CAW cable for
reclamation. The actual separation stage of the process is fairly consistent; how€»ver
the condition of the scrap cable as received by PAC has a major impact on the
process.
Product Quality Variance
The cleanliness of the scrap components - aluminum sheath, plastic, and center
core - directly affects the resale potential and value of these materials. Contamination
reduces acceptability and price of the components. Marketing has focused on the
1100 series aluminum sheath; quality of the aluminum has been high, and scrap
buyers have been pleased with the condition of the components and virtual lack of
49
-------
contamination.
Conditions That Impact Performance
As stated earlier, the condition of the cable when received has a great impact on
processing efficiency. When cable is removed from the poles, it is usually handled
quickly. This often results in permanent kinks in the cable. The chopping process
must be interrupted at each sizable kink as the cable is fed into the Chopper. Cable
which is relatively free of kinks can be fed continuously into the Chopper, saving
handling time.
The fluctuation of scrap aluminum prices will affect economic performance. Scrap
aluminum prices have fallen since the project began, and thus it is vital to minimize
handling the cable prior to separating the components.
Performance Data
Cable is currently uncoiled from the reels by hand; it takes approximately one hour
to prepare 800 feet. A mechanical device to uncoil the cable and feed it into the
Chopper will soon be developed.
The maximum speed of the cable through the Chopper is 18.5 feet per minute.
Approximately 11 feet of cable will produce one pound of chopped aluminum sheath.
Therefore, at maximum speed, the output is 1.68 pounds of aluminum per minute, or
100.0 pounds per hour. The amount of recoverable components increases as the
cable size, diameter, and aluminum sheath thickness increase,
PAC applies a correction factor of ,5 to account for inefficiencies (e.g. start-up,
switching to other cables, kinking of cable). As the scrap arrives at PAC in fairly short
jengths, continuous operation is not possible. Thus, an output of 50 pounds per hour
is the maximum expectation.
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
The Chopper technology is ready to process cable at a permanent site. PAC has
found that the collection of scrap cable is best done when cable companies are
replacing major sections of a system; this allows for larger quantities of cable to be
collected at one time.
As the technology is perfected, a mobile unit may be developed such that cable
companies could process scrap cable as it is removed from the pole. This would
eliminate transportation to the permanent site, minimize the large storage area
required at the permanent site, reduce handling, and enhance profits.
50
-------
Scrap dealers can also benefit from a portable unit. Most scrap dealers currently
bale the stranded cable and export it at minimum prices. Processing the cable into its
components would allow resale of the materials at a higher price to. domestic markets.
Fiber optic cable is being introduced into the industry. As cable systems
continuously upgrade, older aluminum-clad cable will become available for recycling.
Limitations
As scrap market prices fall, materials handling and processing time must be
minimized to maximize profits.
Some cable is manufactured with various sealing compounds between the
components which makes them difficult to separate, or leaves a residue. Another
processing step could be added to separate and clean the components. Should this
step be necessary, a non-hazardous solvent must be identified so as not to utilize any
hazardous materials or create hazardous waste.
Underground television cable is becoming more common. Its different composition
renders it more difficult to recycle.
51
-------
THE COLDCUT™ PROCESS
TO ELIMINATE THE USE OF HAZARDOUS MACHINING FLUIDS
by
Timothy Palmer
Shamrock Industrial, Inc.
Sierra Madre, CA 91024
ABSTRACT
It is estimated that between 260 and 800 million gallons of machining fluid
(lubricant/coolant applied to metal parts being drilled, cut, or otherwise "machined") is
used annually by U.S. manufacturers. Most machining fluids used today are chlorine,
sulphur, or petroleum based and contain additives which make them hazardous. The
Coldcut Process seeks to eliminate the need for hazardous machining fluids by
substituting the use of cold air and a non-hazardous vegetable based lubricant.
Coldcut Process units of varying characteristics were constructed and tested in various
machining applications. ;
INTRODUCTION
PROJECT DESCRIPTION
It is estimated that between 260 and 800 million gallons annually of machininq
fluid - lubricant/coolant applied to mostly metallic materials being cut on machine tools
by machining processes such as drilling, tapping, milling, and turning. Most machining
fluids used today are chlorine, sulphur, or petroleum based and contain additives
which make them hazardous. These fluids are traditionally applied in large volumes
by flooding or spray-misting the machining tools.
The Coldcut Process is an alternative lubricating/cooling method using an
extremely small amount of synthetic/vegetable-based cutting tool lubricant combined
with cold air. The technology enhances: productivity through increased cutting tool
feedrates; cutting tool life by reducing machining temperatures; and geometrical
tolerances by reducing thermal changes in the workpiece.
Unique Product Features
The Coldcut Process utilizes chilled air and a precision cutting tool lubricant
delivery system. The chilled air replaces water or oil as the principal cooling agent.
The application of the cutting tool lubricant is infinitely adjustable between zero and
four ounces per eight hour shift. The cutting tool lubricant is a clean, non-hazardous
synthetic/ vegetable-based oil; traditional coolants typically contain unhealthy or
environmentally unfriendly components. A representative machine tool consumes
52
-------
about 600 gallons of traditional coolants annually; the Coldcut system consumes about
12 gallons. This is a 98 percent reduction in the use of machining fluids and the
elimination of all hazardous machining fluids.
The Coldcut applicator's precision delivery system combines a biodegradable
cutting tool lubricant and chilled air. Ambient temperature airjs forced through a
vortex tube (also known as a Hilch tube or cold air gun) which separates air
molecules, generating cold air at one end and hot air at the other end. The cutting
tool lubricant is contained in a reservoir which is above the Coldcut applicator. The
lubricant is gravity fed into a pneumatic pump in which the pump's adjustable piston
stroke controls the volume of lubricant. The pump is interfaced with an adjustable
timer which controls the number of pump cycles per minute.
The lubricant and cold air travel in separate tubes within a hose to the nozzle.
The lubricant and cold air are mixed at the nozzle which delivers the chilled
air/lubricant to the interface of tie cutting tool and the workpiece (part). The nozzle
must be within one inch of this interface.
The vegetable-based cutting tool lubricant is a highly lubricous fluid that can
significantly reduce friction when the cutting tool is in the cut. However, the lubricant
will vaporize at the relatively low temperature 600° F. The lubricant's ability to last
through the cutting process is greatly enhanced by the cold air, The chilled air cools
the part and cutting tool, thus prolonging the life of the lubricant before vaporization
occurs.
The output of lubricant is so small that only a little residue remains on the
workpiece; most of the lubricant is consumed in the cut. In traditional flooding or
spray mist methods, more residue is left on the parts which may be more difficult to
clean.
With the Coldcut Process, the resulting scrap is dry and clean. In many cases,
because the scrap is not contaminated by ingredients found in traditional coolants, the
scrap can be sold at a higher value per pound.
Typical consumption of lubricant in the Coldcut Process is one to two ounces
per eight hour shift. A thin molecular coating of the lubricant is delivered to the cutting
tool edge while the edge is exposed outside of the cut. The vegetable-based cutting
fluid's high lubricity factor reduces friction more than mineral oils or water based
coolants, and eliminates the need for hazardous, extreme pressure additives
containing chlorine or sulphur. The latter is a major advantage, as thousands of
gallons of hazardous spent coolants are eliminated which are costly to dispose.
53
-------
XDOM- uix
VX--
a.
s
Z3
a.
\\
v.\
\v
0 ^
=> cr
i iti
u. c/)
UJ
UJ:
Of
or
I
O)
iT
54
-------
APPLICATION
Process and Products Replaced
The Coldcut Process can replace most traditional spray mist and flood systems.
Each single nozzle spray mist system consumes several hundred gallons of coolants
each year; a single nozzle Coldcut applicator would typically consume only four
gallons of vegetable-based cutting fluids in the same period. Coolants used in
traditional systems may contain harmful chemicals, whereas the vegetable-based
product is quite clean and fairly benign. Traditional spray misting systems can
suspend chemicals in the air, causing potential inhalation problems. The
vegetable-based fluid is heavier than air, and the minute amount which is not
consumed in the machining process quickly settles to the ground.
A typical machine tool sump consumes .about 600 gallons of coolants per year,
much) of which must be disposed of as hazardous or lands on the shop floor to be
collected by absorbent materials and subsequently disposed. A Coldcut applicator,
consuming only about five to ten gallons of vegetable lubricant each year, prevents
this waste.
Cross Segment Uses
The Coldcut application may be utilized to reduce wear on friction parts. It may
also enhance assembly operations - for example, those dealing with rivets and similar
functions. The vegetable lubricants may have several applications in food processing
or other industries where cleanliness with high lubricity are needed.
PROCEDURE
DEMONSTRATION
Lubricant Selection
Several water-based coolants, synthetic fluids, mineral oils, and
vegetable-based lubricants were evaluated for use in the Coldcut Process. The
selection of a vegetable-based cutting tool lubricant was determined by the criteria
described below:
Pour point
Lubricity (pin and vee block tests)
Compatibility with workplace material
Environmental cleanliness
Employee protection .
Pour point is an issue, as the vortex tube can reduce the air temperature to
below 0° F. Therefore, the cutting fluid must stay liquid below freezing. Water-bassed
coolants were eliminated due to the high pour point - about 32P F. Mineral oils were
not as clean nor were they as lubricous. Some synthetic fluids stayed liquid at low
55
-------
temperatures and had good lubricity characteristics; however, they were not as clean.
Vegetable-based fluids had the best combined characteristics considering the criteria
described.
The vegetable-based product with the best performance and application data is
supplied by Product Solutions. It is compatible with all materials and is safe to
humans. Pour point is approximately 5° F. It is heavier than air so it will not create a
mist or fog in the machine shop. The pin and vee block test, a national lubricity
measurement standard, is 2100 load value to foot pounds (test ASTM D3233A).
Test Parameters/QA Controls
Tests compared the parameters of the following machining processes using
either spray misting or flood cooling:
• Cutting tool life.
• Machine tool productivity - feedrate in inches per minute (IPM).
• Finish - geometrical tolerance and RMS finish of the machined product. RMS is
the Root Mean Square - a2+bz+c2... - and is used to determine the
smoothness of the surface finish by measuring the distance above and below
the mean reference line.
Keeping constant the cutting tool, machine tool, and workpiece as control factors,
the cutting tool life, feedrate, and finish were measured. Cutting tool life was
monitored for increases or decreases. Machine tool productivity was measured by the
metal removal rate to create the part - an increase or decrease in feed rate measured
in IPM. Geometrical tolerance was determined by measuring instruments and
comparing measurements of the control group to the Coldcut group. RMS finish of the
product is quantitative.
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
Described below are several machining applications comparing the Coldcut
Process to traditional processes.
Tapping
Application - Excellent
Material - 8/40 steel; 90,000 PSI
Coolant Replaced - Chlorinated mineral oil-based lubricant
Tool Life - Increased 238 percent
Feedrate - Same
Finish - Slightly improved
Comment - One of the best applications
Payback -1-6 months
Taps are cylindrical or conical thread cutting tools used to produce internal
tads. Tapping combines rotary and axial motion to cut or form the thread. The
56
threads
-------
Coldcut Process works extremely well in thread cutting applications, but does not
perform well in thread forming operations. In thread forming, threads are formed by
pushing metal into the desired shape rather than cutting the desired sl-.ape. Forming
uses pressure rather than a cutting action, and the Coldcut Process cannot handle the
internal heat generated in some forming applications. However, Coldcut may work in
some forming operations such as with mild strength carbon steel.
Drilling
Application - Excellent
Material - A286 stainless
Coolant Replaced - Flood, water soluble
Tool Life - Increased 700 percent
Feedrate - Increased 100 percent
Finish - Improved
Comment - One of the best applications
Payback - Approximately 4 weeks
Drilling is one of the most economical means of machining a hole. It is done with
a tool with one or more cutting lips that transcend to flutes for chip evacuation
Drilling is one of the best Coldcut applications, as traditional cooling methods have
great difficulty accessing the cutting tool's point when the hole depth equals three or
more drill diameters. As a depth of cut increases to this level, the more effective the
Coldcut Process may prove to be.
Boring
- Average
Material - 15/5 stainless
Coolant Replaced - Chlorinated, water soluble
Tool Life - Increased
Feedrate - Increased
Finish - Constant ,
Comment - A good Coldcut application
Payback - Approximately 2 months
Boring is a machining function in which the internal diameter of a hole is
generated in a true position of the centeriine of the machine tool spindle. Most boring
is done with a straight sing|e point cutting tool, and may inhibit the Coldcut Process
When the amount of material to be removed is not very thick (less than .002 inch -thick
metal chip), the metal chip is not thick enough to help draw heat out of the workplace
In this situation, Coldcut relies more on th© cold air than the cutting tool lubricant to
remove heat
Milling
Application - Excellent
Material -15/5 stainless
Coolant Replaced - Chlorinated, water soluble
Tool Life - Increased 100 percent
Feedrate - Increased 40 percent
57
-------
Finish - Constant
Comment - Excellent application
Payback - Approximately 2 weeks
Milling uses a rotating, multiple tooth cutter which removes a small amount of
metal with each revolution of the spindle. Important to the Coldcut Process is that the
miller's cutting edge usually exits the workpiece for a short period of time permitting
reapplication of the lubricant before the tool again enters the cut.
Machining Center
Application - Good
Material -15/5 stainless
Coolant Replaced - Chlorinated, water soluble
Tool Life - Increased 100 percent
Feedrate - Increased 80 percent
Finish - Constant
Comment - Tool changer hits nozzles
Payback - Usually less than 6 months
Machining Centers are CMC (Computerized, Numerically Controlled) machining
tools that provide multiple machining operations. It can function unmanned, employing
an automatic tool changer. Typical Machining Center operations include milling
drilling, tapping, and boring. While the Coldcut Process has great potential with
Machining Centers, it is currently a difficult application. When a tool change is made
the automatic tool changer usually knocks the Coldcut applicator nozzle out of
position. The nozzle may also have to be repositioned to accommodate for the
different cutting tool positions.
Bandsawing
Application - Failure
Material - stainless steel, 12" diameter
Coolant Replaced - Flooded mineral oil
Tool Life - No data
Feedrate - No data
Finish - No data
Comment - Nozzle could not get close enough to the intersection of the cutting
tool/workpiece
Payback - Not applicable
The horizontal bandsaw blade - a long circular band with teeth on the edge -
submerges itself in the workpiece and does not allow room for the Coldcut nozzle to
be close enough to the cutting tool/workpiece. intersection. However, in many
bandsaw applications, an ambient temperature applicator, not employing the vortex
tube, is all that is necessary.
CNC (Computerized Numerical Control) Drilling and Tapping
Application - Excellent
Material - Brass and stainless steel
58
-------
Coolant Replaced - Flood, water soluble
Tool Life - Doubled
Feedrate - Improved
Rnish - Constant
Comment - Nozzle could get close enough to the intersection of the cutting
tool/workpiece and not be hit by the tool changer.
Payback - 6 months
The CMC Drilling and Tapping machine is a simplified CNC Machining Center. Its
tool changer system permits easier access and better placement of the Coldcut
nozzles.
Surface Grinding
Application - Good
Material - Tool steels and stainless steel
Coolant Replaced - Sulphurized mineral oil
Tool Life - Increased 2-3 times
Feedrate - Constant
Finish - Improved
Payback - Improved finish/justified purchase
In surface grinding, minute metal chips are removed from the workpiece by the
mechanical action of irregularly shaped abrasive grains. The Coldcut process works
well with grinding, but various operational issues need to be considered. For example,
the metal chips are very small and light, and if too much lubricant is used -1 ounce
per 8 hour shift is too much - some of the metal chips will stick to the grinding wheel
causing a burn on the workpiece. 1/2 to 1/10 ounce of lubricant per 8 hour shift is
sufficient. In another issue, traditional flood cooling flushes away the swarth (chips) to
the coolant sump. With the Coldcut Process, there is not enough volume of liquid to
carry the swarth away from the cutting tool and workpiece. A vacuum system could
evacuate the grinding dust created during this operation.
Combination Drilling and Countersinking - Drivematic Wing Assembly Machine -
Aircraft
Application - Excellent
Material - Aircraft aluminum
Coolant Replaced - Freon
Tool Life - Increased 100 percent
Feedrate - Remained constant
Finish - Improved to acceptable
Payback - Immediate payback because of improved finish
This was one of the best successes of the Coldcut Process. When Freon - a
chlorofluorocarbon which cools by rapid evaporation - was first replaced, the aircraft
company had difficulty in attaining the desired part tolerance and finish. As the
Coldcut applicator can be adjusted to deliver a precise amount of lubricant, no extra
cutting tool lubricant residue remained on the part which would otherwise cause
problems in the subsequent manufacturing processes.
59
-------
CONDITIONS THAT IMPACT PERFORMANCE;
The various factors discussed below impact performance of the Coldcut Process*.
Air Quality and Supply .
Clean, dry air delivered at the optimum pressure and volume are crucial to the
performance of the Coldcut Process. Dirty air adds foreign particles to the process.
Wet air ices and clogs the applicator nozzle, hampering delivery of chilled air and
cutting fluid. The Coldcut applicator needs a minimum air supply of 18 CFM (cubic
feet per minute) delivered with a minimum of 90 PSI (pounds per square inch). At 90
PSI, 18 CFM in dry, mild weather conditions, the applicator usually produces chilled air
in the low 40°s F.; at 100 PSI, 18 CFM, temperatures in the mid-30°s F. can be
obtained. On hotter, more humid days, it is difficult to optimize cold air delivery,
Coolants and Lubricants
Coolants and lubricants function differently in machining processes. Coolants
control the heat generated in the machining process by quenching with water or oil
based coolants, usually containing sulphur, chlorine, or other additives. Lubricants
reduce friction in machining, thus minimizing heat build-up.
Vegetable based lubricants have different characteristics than traditional coolants.
Clean vegetable fluids no not have any high temperature or extreme pressure
additives, so the range of speeds and feeds in which they work is very narrow.
Cutting Tool Speed and Feedrates
Regulating cutting tool speeds (SFM) and feedrates (IPM) is different in the
Coldcut Process than in flood or spray mist coolants. Relative to flood machining
conditions, speed is usually no more than 50-70 percent, and feedrate is,can be
increased 30-200 percent in the Coldcut Process. Reducing cutting tool speed usually
reduces its temperature; increasing feedrate usually reduces heat in the part.
Nozzle Positioning. Plumbing, and Adaptation
Nozzle placement involves several key issues. The nozzle must be as close to
the cutting tool/workpiece interface as possible, ideally within one inch.
Rexible Machining Cells, CNC Machining Centers, and CNC Turning Centers pose
difficult plumbing issues, as their automatic moving components displace the Coldcut
nozzles. The machine tool programmer must account for nozzle location, positioning,
and automation.
The length of the hose/nozzle extension from the vortex tube should be as short
as possible. The chilled air warms rapidly after leaving the vortex generator,
especially as the hose/nozzle length increases over 5 feet; it should never be over 10
feet.
60
-------
Chip Evacuation
Flood cooling easily flushes metal chips away from the workpiece. Coldcut
Process requires an air vacuum system. Applications where chip evacuation is critical
negates the use of the Coldcut Process, because part quality is impaired.
Human Resources
Machine tool operators' attitudes is a significant issue. Feedrate increase equals
a productivity increase which may mean a loss of overtime pay, a primary concern to
workers. Machine operators and programmers may not realize how critical and
radically different speed and feed set-ups are, and may be reluctant to change these
parameters. If speed and feed adjustments are not made, the Coldcut Process will
fail, creating a negative image which is not easily overcome.
COST/BENEFIT ANALYSIS
The economic viability of the Coldcut Process is best described in a "number of
days" payback period - the number of days to earn the $2,000 cost of the applicator
through productivity rate increases, tool life savings, maintenance clean-up, and
disposal costs. The following formula may be applied:
# days payback = Coldcut Cost Factors
Savings
Coldcut Cost Factors = applicator cost + lubricants + air costs
Savings = (machining time x feedrate increases) + (cutting tool life savings) -t-
(maintenance clean-up and disposal savings)
The following example may be cited:
Milling 15-5 stainless on a Mori Seiki v40 Machining Center
Cutting Tool Usage/Day
$50.00
Machining Time ($50/hour x 4 hours/day)
$200.00
Maintenance (t/3 hour x $12/hour)
$4.00
Coolant Use/Day
$0.50
Coolant Recycling/Disposal Costs/Day
$2.00
Tool Life Increase
100%
Feedrate Increase
40%
61
-------
Maintenance (5 min. x $12/hour)
Cutting Tool Lubricant
Air Cost ($0.375 x 4 hours/day
Dollar \fe$i» ^a^ngs^w'Day"^. *'*'*^€"\ * s ,? * *, -^ \C, * '
Cutting Tool Usage (50% tool life improvement x tool
costs)
Machine Time (40% feedrate increase x 4 hours)
Clean-up Savings ($4 traditional vs. $1 Coldcut)
Cutting Ruid Savings (Traditional: $0.50 coolant +
$2.00 disposal vs. Coldcut: $1 .00 coolant + $1 .50
air)
Total Daily Savings
Cost of Coldcut Applicator/Total Daily Savings =
Number of Payback Days
$1.00
$1.00
$1.50
' ' /"••^ Vj. ^*%-?xC ' ';'''••
\ ^ - , '\"f\ \4j- '" -- ^" 1
$25.00
$80.00
$3.00
$0.00
$108.00
$2,OOO/$108 =
1.8.52 days
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
A basic portable applicator was developed, manufactured, sold, and proven in the
industrial manufacturing process. Cutting tool lubricants were discovered in the
market place that lend themselves well to the Coldcut Process. The technology
reduces cutting tool costs, increases productivity and product quality, and solves
several costly environmental issues.
Machining industry potential is excellent for this following tooling operations-
tapping, drilling, milling, countersinking, counterboring, spot surfacing, and surface
grinding. Potential is very good for: turning, boring, reaming, shaping, and planing
(considering improved processes and the likely development of more appropriate
machining fluids). For conventional machine tools performing dedicated tasks, the
Coldcut Process is excellent; however, dedicated machines probably comprise less;
than 10 percent of the machine tool market. For multi-function machine tools, the
potential is greater, but the application more challenging; further development is
required to successfully replace traditional coolant delivery systems on complex tools.
Barriers
The limitations of the Coldcut Process have been discussed throughout this report.
To summarize, they encompass four key areas:
62
-------
• Air - Quantity, volume, pressure, and consumption.
• Mechanical Location - Length of hose/nozzle from the vortex generator to the
workpiece/cutting tool intersection; nozzle must be repositioned for multi-function
tools.
• Lubricants - Improved lubricants will enhance performance.
• Human Resources - A lack of understanding and resistance to change hinders
implementation of the new technology.
Potential Solutions
• Air - Measuring and tracking volume, pressure, temperature, and quality will
optimize air consumption and Coldcut performance.
• Mechanical Location - The applicator nozzle must be kept 1 inch or less from
the workpiece/cutting tool intersection. The length of the hose should be less
than 5 feet. The Coldcut Process can be integrated in the design of a
multi-function complex machine tool; a computerized robotic nozzle manipulator
interfaced to the machine tool controller would optimize nozzle positioning and
placement.
• Lubricants - Environmental concerns are causing development of new coolants
' and lubricants, some of which will significantly enhance the Coldcut Process.
• Human Resources - A multi-level educational program on the Coldcut Process
can inform machine tool operators, programmers, engineers, and management
about the technology's benefits.
Issues to be addresses include:
— Environmental and health concerns
— Productivity enhancements
— Tool life increases
— Nozzle location and placement requirements
— Speed and feedrates
— Traditional versus Coldcut techniques
63
-------
RECYCLING RADIATION-CURABLE ORGANIC WASTE
BY CASTING STRUCTURAL AND DECORATIVE OBJECTS
by
Harry Katz & Radha Argarwal
Utility Development Corporation
Livingston, NJ 07039
ABSTRACT
Radiation curable coatings (e.g., overprint varnishes used by the printing
industry) are replacing the old solvent based coatings and formulations in the chemical
and pnnting industries. The production of radiation curable coatings generates liquid
polymer waste that is difficult and expensive to dispose. Utility Development tested
vanous chemical catalyst systems and fillers to produce useful molded decorative and
structural products (e.g., park bench supports, parking lot bumpers) using liquid
polymer wastes generated in the production of radiation curable coatings. During the
research and development program, appropriate catalyst systems were selected and
optimized. Type of filler, filler ratios, cure rate, type of molds, and mold release
materials were determined. The strength and weathering properties of cured test
samples were optimized, and large castings were made. i
INTRODUCTION
PROJECT DESCRIPTION
A cun-ent major focus in the chemical formulation and printing industries is the
production of "radiation curable" coatings - overprint varnishes on various substrates -
to be used as a substitute for the old solvent-based coatings. The production of
radiation curable coatings generates considerable quantities of liquid polymer waste)
that is difficult to dispose. This project tested various fillers and chemical catalyst
systems for the purpose of producing useful molded decorative or structural products
(lawn ornaments, parking lot bumpers) from these liquid polymer wastes. Strength
and weathering properties of cured samples were also determined.
Unique Product Features
Products were cast from liquid organic wastes that would otherwise be disposed
as hazardous. The waste was rendered non-hazardous by polymerizing the
unsaturated monomers and oligomers. The polymerization forms a very high
molecular weight polymer that is cross-linked, thereby making it stable and
non-hazardous. The polymerization was accomplished through a selected method for
catalyzing the curing material. The catalyzed materials were then cured in molds to
make the castings. See Figure 1.
64
-------
Figure 1. Process for Converting UV-Curable Waste Into Decorative and Structural
Castings
UV-Curable
Waste
Inert
Fillers
Catalyst
System
Mix
Thoroughly
Pour Into
Open Mold
Ambient
Temperature
Cure
Various Types of Molds
Such as Aluminum Castings
Can Be Varied From,
1 to 16 Hours
Remove
From Mold
Mold Usually Consists of
a Number of Assembled
(Bolted) Parts
Surface
Coat
And Decorate
Casting
65
-------
APPLICATION
Products Replaced
The products made from the scrap coating liquids are traditionally produced
from concrete or plaster. Products such as park bench supports, highway markers or
dividers, and lawn statues can be cast from organic UV-curable coating liquids. These
equivalent castings from waste, which usually require expense to remove or dispose,
are much lower in cost than standard commercial products.
Wastes Prevented
Radiation curable coatings are reactive polymer systems that cure rapidly by
exposure to radiation such as industrial ultraviolet (Uv) lamps or electron beams. The
coatings may be used for a variety of applications, including:
Decorative coatings for paper, plastic, and wood
Abrasion resistant coatings for lenses and optical fibers
Solvent resistant coatings for labels
Fluorescent coatings and many novelty coatings, such as for holograms
These products are solvent-free, cure rapidly, and consume small amounts of
energy.
Waste coating materials result from storage beyond the recommended shelf life,
contamination, or error in coatings preparation. These waste coating liquids are
typically disposed of as hazardous waste. Combining the. waste coating liquids with
fillers and a catalyst system for casting purposes eliminates the need (and the
associated liability) for disposing of the waste.
Cross Segment Uses
Other industries that generate reactive liquid waste products can use this
process technique, however the appropriate catalyst and filler materials must be
selected. Companies that generate certain types of solid wastes (e.g., fiberglass
molding) may be able to use an analogous process: pulverize the waste, and use an
inexpensive thermoset or thermoplastic resin as a binder to make an end product.
Moreover, the resin binder chosen could be a waste product itself.
PROCEDURE
DEMONSTRATION
Utility Development selected and studied various catalyst systems^ fillers, and
filler levels to determine the proper materials and formulation for a satisfactory casting
and an acceptable cure time.
66
-------
Catalyst Systems
MEK peroxide was used as the main catalyst, as the waste coating is an
unsaturated resin. Peroxide catalysts require an accelerator to provide a convenient
room temperature, overnight cure.
A number of peroxides were studied, and most castings were made with
Lupersol DDM-9, manufactured by ATOCHEM of Buffalo, NY.
Accelerators evaluated included Hex-Chem 977 and Nap-All (4 percent
calcium), Mooney Chemical, Inc.; 15 percent potassium naphthenate (Nuodex, Inc.);
and 6 percent cobalt naphthenate.
Initial catalyst/accelerator trials showed the best results with MEK peroxide and
6 percent cobalt. A catalyst system containing cumene hydroperoxide and 4 percent
vanadium Hex-Chem was also effective, but produced a too rapid cure rate. Another
system containing 4 percent Calcium Nap-All and MEK peroxide provided good results
and eliminated the heavy metal cobalt from the process. Calcium naphthenate is not
usually effective in this type of system; the presence of aluminum fiber in the filler may
facilitate a suitable exothermic reaction with the calcium material.
This final combination provided a cured part in about ten hours at room
temperature. This is sufficient time for air bubbles generated during the mixing and
pouring of the material to rise to the surface of the casting before the cure is
complete. This provides a stronger casting with fewer trapped bubbles and surface
voids.
Fillers
Fillers evaluated include Englehard ASP-170 clay; a -325 mesh Periodite
weathered mica, calcium carbonate (Thompson-Weinman Atomite); Nyco's
Wollastonite G and Wollastokup; and Malvern Minerals' 325 Novakup 1100 and 325
Novacite. Fillers were added to the waste coating materials to the point where the
material was still at pourable viscosity. The high filler content was necessary to
minimize shrinkage cracks in large castings.
The main fillers for recent castings were 325 Novakup 1100 and 325 Novacite.
A typical formulation is shown in Table 1.
Table 1. Casting Formulation
ff ff f ffff ff f S ~" f"* ~"fff ffffff s ;-..-. ff f '
ff ff f fjff f fff f f f ff f fff Vf f f -SfS •_' *°*° i \, £ *° i' *•"••"•• •_ f f .
'£-,?;,-,;'./,>< ?,<«' V':'\W88M- ±^'v, ':%-''!
Malvern Minerals'325 Novakup 1100 or 325 Novacite
Meadowbrook Inventions' Silver IE (aluminum) Fibers
Radiation Curable Waste
Mooney Chemical's Ca Naphthenate (4%)
Lupersol DDM-9 MEK Peroxide (ATOCHEM)
' <-%WibhtV ".,"'"•••
57.0
2.0
38.0
1.5
1-5
67
-------
Surface Coatings
Castings were coated to improve appearance and to provide an odor barrier for
the trace amount of unreacted monomers.
Initial coating trials with commercial acrylic paint provided good cosmetic results
but not a good permeation barrier for the residual odor.
A number of water-based acrylics were then evaluated. These did not provide
a good permeation barrier for traces of unreacted monomer as indicated by a slight
residual odor. Talc filler was unsuccessfully added to improve barrier properties;
adhesion quality was also compromised.
The focus turned to epoxy-based coatings. To obtain an easily applied coating
without the use of solvents, a reactive dilutent, Ciba Giegy 1,4 butanediol digiycedol
ether, was added. Various colorants and talc filler were also added. The coating
hides minor surface pitting and other defects. The main coating formulation is shown
in Table 2.
Table 2. Coating Formulation
,1, : ^^f^tr:^^
Shell Chemical's Epon 826
Henkel Corporation's Versamid 140
Ciba Gieg/s 1,4 Butanediol Digiycedol Ether
Cyprus Mistron Vapor Talc
Cabot Corporation's Cab-O-Sil
Perm Color's 18W286 White Epoxy Pigment
:-i*r *j*.M&%fcr% * * l
30
30
15
20
5
2
Ornamental castings were prepared using commercially available molds.
Castings and their approximate weights are shown in Table 3.
Table 3. Ornamental Castings and Approximate Weights
Cat
Rabbit
Duck
Dog
Lion
14
120
68
-------
Structural castings, including a highway marker and a parking lot bumper, were
also made. One key requirement of such products is a compressive strength of at
least 2,000 pounds per square inch (psi). Utility Development castings have a
compressive strength of 7,000 psi.
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
Utility Development successfully developed a formulation to cast structural and
decorative objects from radiation curable organic waste materials.
Product Quality Variance
Product feasting) quality can vary, as the starting waste material is not the
same from batch to batch and will have different cure characteristics. Initial screening
tests can allow the formulation to be adjusted to the appropriate ration of fillers and
catalysts.
Filler type and loading, catalyst system and configuration, additives, mold type
and size, molding process, and cure cycle also affect product quality.
Conditions That I mpact Performance
Formulations and moldings variations caused some initial problems in obtaining
a quality product. Due to the multi-functional acrylates in the waste product, castings
without the addition of fillers resulted in severe cracking .due to cure shrinkage. The
final cure rate was often influenced by the type of filler used. Also, some filler
formulations exhibited oxygen inhibition of cure which resulted in a tacky surface after
the bulk of the casting solidified. Of the fillers used, mica prevented curing, and clay
considerably slowed cure rate; other fillers did not inhibit the cure.
During the final two months of the project, castings using the calcium
accelerator were prepared which had only slight surface porosity and possessed good
compressive strength. Initial surface hardness was low, and the surface could be
indented by fingernail pressure. A slight surface tack was also noted. After one to
two weeks storage at room temperature, hardness increased such that the surface
could not be readily scratched and was non-tacky. When the casting was placed
outdoors in the sun, the surface became scratch-resistant and tack-free within one to
two hours. Compressive strength of these samples ranged from 6,000-7,000 psi.
Cost/Benefit Analysis
The starting material is a waste product, and the fillers are low cost. The
catalysts, although expensive, are used at very low concentrations. Molds can be
purchased at moderate costs and are suitable for casting many parts.
Utility Development's sister company, Rad-Cure Corporation, disposed of
69
-------
approximately thirty, 55-gallon drums of radiation curable waste in 1988 at a cost of
$225 per drum for liquid waste and $900 per drum for gelled material.
The cost analysis per pound of finished material is shown in Table 4.
Table 4. Cost Analysis Per Pound of Finished Material
C^rtalM!a^l.^%-i
Filler
Aluminum Fibers
Radiation Curable Waste
Ca Naphthenate (4%)
DOM-9 MEK Peroxide
^Totai MateflsJOwt^Ar*' "^ ^
^Jx&^ljffiS
57.0
2.0
38.0
1.5
1.5
.^S^ei&frvf^
.15
3.00
0
5.00
5.00
.08
.06
0
.07
.07
$0.28/lb.
The cost for surface coating is shown in Table 5.
Table 5. Surface Coating Cost
. ..r :.. Suii&SiiSl^^
Epon 826
Versamid 140
1,4 Butandeiol diglycedol ether
Vapor Talc
Cab-O-Sil
18W286 White Epoxy Pigment
S. j^i^:^;
30
30
15
20
5
2
"***"',*„ Mfc^-*1***-?
2.50
2.50
1.00
.15
.15
4.00
.75
.75
.15
.03
.007
.08
Since only a thin layer of the coating is used, the following estimate is made:
Casting Material + Surface Coating Cost = $0.35./lb.
Labor Charges = $0.20/lb.
Total Labor + Material Cost = $0.55/lb.
70
-------
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
Utility Development successfully demonstrated the practicality of recycling
radiation curable waste. Additional development is necessary to define all parameters
for efficient conversion of the variety of scrap materials being generated by the rapidly
expanding radiation curable industry. The resulting product is strong and of low cost.
The product meets strength requirements (when such a comparison is necessary) of
similar products, although it is not necessarily of superior quality. The main benefit is
th© beneficial use of a material that is normally disposed at a significant cost.
Large or small firms that produce or use radiation curable liquids can recycle
their waste through this process. Little initial investment is required to begin such a
recycling program.
Liability associated with the disposal of hazardous waste is eliminated.
Barriers .
Because waste quality and characteristics vary widely, one specific formula or
handling procedure cannot be established for all lots of radiation curable wastes.
Incoming quality control and testing will allow catalyst systems and filler adjustment for
suitable end results. For example, it may be desirable to blend some liquid from a
poorly reactive lot of waste with waste which readily cures to a hard and tack-free
surface.
71
-------
RECYCLING INK WASTES
FROM PACKAGING GRAVURE PRINTING
by
William M. Jones
Resource Recycling and Remediation, Inc.
Pittsburgh, PA 15222
ABSTRACT
Resource Recycling and Remediation, Inc. (3R) demonstrated the commercial
and technical feasibility of recycling a substantial volume of hazardous waste ink from
the packaging and product gravure segments of the printing industry - versus the
standard industry practice of incineration. 3R has already developed recycling
technology and demonstrated the feasibility for recycling publication gravure ink waste
However, the research must be repeated, as packaging and product inks are
dissimilar. The technology will be useful to the estimated 900-plus gravure plants
throughout the U.S., and more than 120 product gravure printers, the success of the
project will mean that millions of pounds of hazardous ink wastes will be recycled
annually, thereby eliminating their environmental impact and reducing disposal cost to
generators,
INTRODUCTION
PROJECT DESCRIPTION
Resource Recycling and Remediation (3R) demonstrated the commercial and
technical feasibility of recycling hazardous waste ink from both the packaging gravure
and product gravure segments of the printing industry. The Company has already
developed recycling technology and demonstrated the feasibility for publication qravure
ink waste. However, packaging and product gravure inks are dissimilar from
publication inks, and the research and demonstration must be repeated Publication
inks are four colors: red, blue, yellow, and black. Packaging and product inks are
blended to the exact color specified by a client.
Following analysis of waste ink from a particular printer, 3-R brings mobile
recycling equipment to the printer to reformulate the waste ink on site. All waste ink
(of any color) is currently recycled into black ink and returned to the printer.
Unique Product Features/Advantages
1.
Ink Quality - Waste inks, which are considered substandard, are returned to
original quality, while variations in color are effectively negated throuah
dilution into black. *
72
-------
2. Market - Packagers are actively exploring how to recycle their spent inks as
well as buy inks that contain a percentage of reclaimed materials to meet
market demand for a recycled product.
3. Value Added Products - Typical black ink costs $12 per gallon; other colors
are more expensive. Waste ink disposal costs approximately $5 per gallon.
Thus reclaimed inks have added value, as they cost $12 to otherwise
purchase and save $5 through reuse. The cost of a gallon of recycled ink
is $9.09.
Process Schematic
Figure 1 shows a process schematic for the ink recycling process.
Figure 1. Ink Recycling Process
Process Schematic
Adjust Strength
with extender and/or
viscosity with solvents
PURCHASED
JOB
PRESS READY
INK
PROPOSED
Waste Ink Residue
i
Filtration
to Reuse
Wash Solvent
4>
Clarification
to Reuse
Solvent vapors to
incinerator or
solvent recovery
t
PRINTED JOB
I
Unused ink (press returns)
stored for next job
i
Press equipment (cylinders,
pans, etc.) to wash up
4
PARTS WASHER WASTE
Waste Ink
Residue
Wash
Solvent
73
-------
APPLICATION
Process Replaced
J.W. Ferguson and Sons' (JWF) was the participating printer in this
demonstration project. Standard procedure for JWF involves washing a number of
ink-laden press parts and containers in a mechanical parts washer. Prior to washing,
free ink is scraped into a drum to minimize contamination of the washing solvents.
The parts washer is purged every two days of 250 gallons of ink-saturated solvents*.
Both the purged solvents and ink are collected in drums and shipped off-site for
treatment and disposal.
Changes to the above procedures can be implemented in two steps:
Prior to parts washing, inks are segregated according to their type or
application.
Purged washer solvents are processed for reuse (intervals between purges
may change).
Wastes Prevented
Generation of waste package gravure "C" type inks (comprised of modified
nitrocellulose and an ester class of solvent) and waste solvent - F005 hazardous
wastes - will be reduced through reclamation.
JWF generates the following waste materials each month.
275 gallons solid inks (scraped from parts)
5,000 gallons solvents (purged from parts washer)
250 - 500 gallons liquid ink suspended in waste solvent (ink removed from
parts in parts washer)
Cross Segment Uses
|nk recycling can be applied to the many printing markets and ink types. 3R
has enjoyed success in recycling "B" type gravure inks and similar results have been
found with "C" type gravure inks (the difference is the type of solvent used in the ink).
The market in non-gravure printing is significant as seen in Table 1.
Table 1. Non-Gravure Industry Applications
Type1 - *-
Cold Web
Heatset
l?^^*&&*i.\^^;f ~*>
Newspapers, telephone directories, advertising
supplements, books
Magazines, books, brochures, catalogs,
advertising supplements
' •• - -.^ % - ^' *»"•;• "')
&* ' # I&SK &&$& , \'\
2,200
600
74
-------
Ink recycling concepts can be transferred to the coatings industries. Solvent
recovery is already widely practiced, and this excellent example can serve to further
the acceptance of this practice.
PROCEDURE
DEMONSTRATION
Ink Recovery
Before being placed in the parts washer, each press part is manually scraped
of ink, and the semi-solid residues (inks, coatings, adhesives, and grease) are placed
in 5-gallon metal kits. The scraped parts are placed in the washer for 30 minutes and
the remaining sludge residues from the parts washer are removed and disposed of as
hazardous. (Eventually this sludge may also be reclaimed.) Approximately five
55-gaJlon drums of this sludge are generated each month.
The solids level of these scrapings is high since they are comprised of polymers
and pigments (ink components) with relatively little solvent. Ink recycling trials were
conducted as follows:
A recovered semi-solid residue sample was taken at random from a 5-gallon
"parts scraping kit," making certain no adhesive, metallic ink, or grease was
included. By mixing ink residue with recovered solvent at a ratio of 2:1, a high
viscosity (35-40 seconds/#2 Zahn) material was produced. Lab drawdowns
showed the sample to have good color strength with a dark purple tint. Further
dilution with recovered solvent (estimated final ratio of 1:1) brought viscosity to
press conditions (approximately 20 seconds/#2 Zahn). Color strength
weakened as expected. Addition of 30 percent black ink extender varnish to
the fluid ink residue increased gloss.
Side-by-side drawdowns were made of the diluted extended ink residue,
press-ready black high gloss ink, and a blend of the press-ready black ink with
approximately 5 percent diluted extended ink residue. A slight color and gloss change
was noted in the blend versus the black control ink. JWF technical personnel
suggested that the recovered adjusted ink residue be added at 5-10 percent to the
virgin (not yet extended) black ink. This was successfully accomplished with no
difference seen in quality.
Ink Reformulation
Semi-solid residue scrapings were shown to be useful in extending black inks in
th© JWF laboratory. Two 1-gallon randomly selected ink residues were used in the
final phase of the study - one ink was dark yellow, the other a blue-black. The only
precaution was to ensure that no machine grease, adhesives, or metallic inks were
present in the samples. The residues were combined yielding a greenish black
mixture. This is called RB - recycled black.
75
-------
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
In the JWF laboratory, a variety of blends of RB with virgin commercial black
ink (VB) used by JWF were made. These were compared with both extended (2 parts
VB and 1 part extender varnish) and unextended VB. Laboratory evaluation included
initial viscosity values of the blends, dilution to 17-20 seconds on a #2 Zahn cup using
isopropyl acetate, and color strength and shade assessment of drawdowns.
While initial lab screenings were largely compared to extended VB, the press
trial was on a production job where unextended VB was used at a viscosity of 17
seconds/#2 Zahn. To prepare for this, the two gallons of RB were blended with four
gallons of VB and filtered under pressure. This VB:RB 2:1 blend had a viscosity of 89
seconds/#2 Zahn, and was free of extraneous particles when examined as a
"washout" on a 45 micron screen. By comparison, the unfiltered RB showed
particulate residues when examined as a "washout" on the 45 micron screen.
Various blends of the filtered VB/RB material were made with VB, diluted with
isopropyi acetate to press viscosity, and evaluated as lab drawdowns versus the VI3
being run on a production job at JWF. The most acceptable blend for color strength,
gloss, and shade was 91.5 percent VB and 8.5 percent RB. This shade was judged
slightiy better (by JWF personnel) than the VB control.
Press Trial
A 16-inch wide Chestnut Engineering Gravure press was running the above
cited job. The press has eight stations, with blue, gold, black, and clear overprint
varnish applied. Oven temperature was 125° F (web temperature approximately 85°
F), with a web speed of 390 feet per minute.. After several thousand feet of
production, the VB ink was replaced with the above-described VB/RB blend which was
adjusted to the same press viscosity of 17 seconds/#2 Zahn with isopropyl acetate.
Production continued with a marker placed in the take-up roll to indicate the change.
Several thousand square feet were produced to allow sampling versus the control.
High resolution scanning of the roll by JWF experts indicated identical quality to the
control. Off-line evaluation confirmed the material to be identical in quality and
salability. Each gallon of the VB/RB printed over 10,000 square feet of material for
this job. Approximately 4 gallons of VB/RB (10 percent RB) were used for the trial
press run.
Steps taken to control product quality include segregation of waste inks
according to ink type, filtration, dilution of reclaimed inks with virgin black inks, and
laboratory analysis to ensure quality.
Should it be determined that inks extracted from the parts wash are
recoverable, it will become necessary to wash parts laden with different types of inks
separately. Parts segregation to this extent would mean a significant change in
operating procedures for the printer.
76
-------
Cost/Benefit Analysis
As Figure 2 illustrates, three key factors dictate the project's cost effectiveness:
Disposal cost
Ink value or replacement cost
Recycling cost
Second only to quality of the ink, cost savings is a key element in gaining
customer acceptance in ink recycling. 3R learned that printers will not recycle at any
cost; recycling costs must be less than the cost of new ink, not merely competitive.
For significant waste minimization to occur, research must continue to explore
efficient methods of extracting inks from parts washing solvent without damaging the
ink. Each month, JWF ships an average of 5,000 gallons of purged wash solvent for
disposal which contains 5-10 percent ink. This ink, if recoverable, has a value of
$3,000-$6,000 per month.
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
The recycling of publication gravure ink wastes is feasible; the main incentive to
printers is saving money. The high value of packaging inks (currently $1.50 per
pound) and the rising cost of disposal add up to significant potential savings.
Target industry potential is high if cost factors can be conveyed. Consumer
product demand for recycled materials may promote manufacturers' use of recycled
inks.
Barriers
Factors such as risk reduction and environmental concerns, in general, do not
yet engender commercialization. Monetary issues are the main driving force towards
acceptance of ink recycling.
77
-------
£2
to
s
I
- E E
|| |
- JS §>
l§ 8
s 1 I
&tt
z | r
1 * «
Iff
J3 -O «
"5
l
t
f
a:
CM
£
o>
il
78
-------
HYDROCYCLONE TECHNOLOGY TO REDUCE
PLANT PATHOGENS IN IRRIGATION WATER
by
Roy D. Lister
Hydro-Separation Systems, Inc.
(A Modular Protection for the Environment Company)
Houston, TX 77077
ABSTRACT
Plant pathogens in irrigation water is a serious problem and source of damage
to crops and turf (especially seedlings) in the agriculture, nursery, and commercial
lawn maintenance (e.g., golf course) industries. The problem of plant pathogens has
historically been controlled by the application of chemical fungicides. This project
proposes to evaluate the effectiveness of hydrocyclone technology to eliminate the
problem at the source by reducing the presence of plant pathogens in irrigation water,
and thereby eliminate or substantially reduce reliance on chemical fungicides.
INTRODUCTION
PROJECT DESCRIPTION
Hydrocyclone technology has been employed by Hydro-Separation Systems to
improve the quality of irrigation water by reducing the source of damping-off disease,
namely plant pathogens such as pythium, in irrigation water.
Damping-off disease is prevalent world wide, affecting many types of plants.
The greatest damage is done to seeds and seedling roots. The fungus also may
attack the fruits of older plants, causing the fruits to spoil in the field or in storage.
Fungicides are typically used to control this plant disease. However,
misapplication of fungicides or certain conditions, such as heavy rains, can spread the
chemicals to streams and groundwater supplies. Thus, the project's goal is to reduce
the use and environmentally negative effects of fungicides by reducing or eliminating
the presence of plant pathogens. The improved quality of the water feed diminishes
the need for the use of fungicides, thus reducing the amount of fungicide in the
eventual run-off from the crop field.
79
-------
Hydrocyclone technology is fairly simple. Pressure energy supplied to a water
slurry by a pump is converted into centrifugal force due to the inside geometry of the
hydrocyclone. A hydrocyclone is shown in Figure 1.
Figure 1. Hydrocyclone
CONE
APEX
SOLIDS DISCHARGE
As the water spins, the heavier materials, such as dirt, are forced to the walls of
the cone where they move down and out through the bottom opening. Clean water is
displaced to the cone's center and exits through the top of the hydrocyclone. Up to
3000 g's of force are exerted on the particles at the bottom of the cone. This high
sheer, it is believed, is responsible for the destruction of the plant pathogen population
in the water.
80
-------
Several benefits to the irrigation water were realized during the project:
1. The majority of plant pathogens were removed or destroyed;
2. Most bacteria were removed or destroyed;
3. Silt was removed, so that soil drainage was improved; and
4. Water was oxygenated for healthier plant growth.
Figure 2 illustrates the irrigation system retrofit for cyclonic silt removal.
Figure 2. Irrigation System Retrofit for Cyclonic Silt Removal
IRRIGATION SYSTEM RETROFIT FOR CYCLONIC SILT REMOVAL
CVCLOMC ruw
mur * WJTCH
OWCTO) MTAKE KMCEN
Solids can be discharged to the water source, as depicted, or may be collected
separately.
81
-------
APPLICATION
The hydrocyclone process is intended to reduce the need for fungicides in
irrigation water, thus reducing environmental and health hazards associated with their
use.
Industries which could benefit from this technology include agriculture, turf
farms, golf courses, and nurseries. All these industries intensely use water and
management chemicals. Introducing a hydrocyclone into the irrigation system can
greatly reduce the need for fungicides.
PROCEDURE
DEMONSTRATION
Eleven test sites were part of this study: 8 golf courses (water sources: Trinity
River, ponds, and city water); a peanut farm (water source: well water); a sod farm
(water source: well water); and a nursery (water source: pond water fed by a well).
Plant pathogens were found in water samples from all sites, while the pythium fungus
was found at 7 of the 9 sites selected for that fungus.
Hydro-Separation Systems constructed a mobile test unit for sampling
procedures. It consisted of a trailer with both a gas powered and an electric driven
pump, flexible hoses, and an aluminum test stand which supported a 3 inch
hydrocyclone.
At the test site, water was pumped for several minutes through the hoses from
the source into the hydrocyclone at 45 pounds per square inch (psi). 2 gallons each
of FEED water (water pumped into the hydrocyclone), OVERFLOW (clean processed
water from the top of the hydrocyclone), and UNDERFLOW (approximately 5 percent
of the feed volume plus dirt, silt, and debris) were taken to Texas A & M University's
(TAMU) Dallas laboratory for analysis. The principal investigators at TAMU were
Phillip F. Colbaugh, Ph.D., and Kirk Bond.
Fungi Tests
At TAMU, 15 centimeter petri dishes were used for all fungal tests. For each
10 plates, 500 milliliters of corn meal agar was prepared. To the prepared agar was
added 10 milligrams Primaricin, 200 milligrams Ampicillin, and 25 milligrams Rifamycin
SV.
82
-------
For each water sample, either 15 or 30 plates were prepared. (This number
was dependent on the number of samples taken in a given week and the number of
plates available.)
5 milliliters of the water sample was pipetted into each plate. The agar was
poured over the water sample and quickly swirled to mix. The plates were allowed to
set for 2 to 4 days until data was taken. Figure 3 depicts cumulative fungus data.
Figure 3. Cumulative Fungus Data
Cumulative Fungus Data
10
8
Colony Mean Per Plate
1
1a 1b 2a 2b 3 4 5 6 7 8 9 10 11 12
Site Identification Number
Feed
Over
83
-------
Data were varied from each site. Values from the FEED ranged from 0 2
fungus colonies per plate to 8.3 colonies per plate. OVERFLOW values ranged from
0 to 24 colonies per plate. UNDERFLOW ranged from 0 to 120 colonies per plate.
The total data mean demonstrated a decrease in fungal colonies per site mean from
FEED to OVERFLOW of 16.0 to 6.0, or a decrease of 62.5 percent. However, using a
mean percent decrease, the reduction was 45 percent due to an unusually high data
set from one of the sites. This decrease, although significant, does not follow the 20-1
concentration factor expected by Hydro-Separator. The high data variation suggests
that multiple factors, including fungus size, determine what portion of fungi are
removed.
Pvthium Tests
In examining Pythium removal, the percent decrease from FEED to
OVERFLOW was 54.5 percent. The data suggests that on a larger scale Pythium
removal is no different than that of other fungi. The Hydro-Separator does not select
for a specific fungus type.
Bacteria Tests
The Hydro-Separator was also tested for bacteria removal. For each sample
FEED, OVERFLOW, and UNDERFLOW, a separate dilution chain was set up. 10 '
milliliters of sample were placed in an autoclaved graduated cylinder with 90 milliliters
autoclaved deionized water. The top was covered with parafilm and the mixture
shaken. 2 milliliters of this 1:10 mixture were added to 18 milliliters of water in a test
tube to yield a 1:1000 mixture. The 1:500 dilution was obtained by adding 1 milliliter
of the mixture to 4 milliliters of water in a test tube.
From each dilution, 1 milliliter of sample was pipetted into the bottom of a
disposable petri dish. Plate count agar was poured directly into the plates which were
then inverted to inhibit fungus growth. Readings were taken after 2 to 3 days and
dilutions which quantitatively fell between 30 and 300 bacteria per plate were used for
analysis.
The following different plating dilutions and counting techniques were used.
The correction factors account for the use of two different sizes of petri dishes.
Method 1 - No dilution. Since plate counts were so high, a 4 square
centimeter on each plate was measured and the number of colonies found in
that square was multiplied by 38.47 to get the correct plate area of 153 86
square centimeters.
Method 2 - Three replications each of 1:100 and 1:500 dilutions were made.
All but one set were full plate counts. One set with a high number of colontes,
84
-------
used a partial plate count of 4 square centimeters. The count was multiplied by
19.6 to get a total area of 78.5 square centimeters.
Method 3 - Five replications each of 1:100 and 1:500 dilutions were made.
Certain sets were partial plate counts of 4 square^ centimeters. These numbers
were multiplied by 19.6 to get a total area of 78.5 square centimeters.
Method 4 -- Five replications each of 1:100 and 1:500 dilutions were made. All
were total plate counts.
Discussion
In accordance with standard microbiological principles, the data chosen was the
set with values which fell closest to the range of 30 to 300. The means found suggest
that the OVERFLOW had 74 percent of the bacteria removed. However, computed on
a mean percent, it was 50 percent; the 74 percent, as in the fungus report, is inflated
due to unusually high date sets. The decrease of 50 percent is very close to the 45
percent decrease found in the fungus experiments. Likewise, the UNDERFLOW was
concentrated 680 percent, however not all sites had concentrations and removals to
these degrees. Further study is necessary for conclusive results on the
Hydro-Separator's potential to remove bacteria from the water supply.
Dissolved Oxygen Content
The violent action of the Hydro-Separator suggests the machine could be used
to enhance the dissolved oxygen content of water samples.
From each site, three standard samples were taken: FEED, OVERFLOW, and
UNDERFLOW. Measurements were done at either the laboratory or on site using a
Cole-Parmer 5946-50 Oxygen Meter. For each sample, three replications were done,
and a mean taken. The original measurement was in parts per million dissolved
oxygen which was taken after the meter was calibrated using air temperature. From
this, the percent saturation of dissolved oxygen could be taken using the water
temperature.
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
It is technically feasible to use hydrocyclones to remove pythium from irrigation
water. The average removal (all test sites) was 70 percent.
85
-------
From material balances, approximately 60 percent of the original pythium was
actually destroyed, about 10 percent of the original number of pythium colonies being
discarded with the silt, while the remaining 30 percent left the hydrocyclone with the
"clean" water.
Other plant pathogens are affected by the hydrocyclone. A material balance of
the total fungi counts indicates that 54 percent of the original total fungi are destroyed.
70 percent of the total fungi are removed from the "clean" water, with 16 percent
discarded with the solids in the underflow.
The hydrocyclone has a pronounced effect on bacteria, probably due to the
combined effects of high shear and the saturation of the water inside the hydrocyclone
with oxygen. From a mass balance perspective, 74 percent of the bacteria are
destroyed, with only about 1 percent of the original bacteria exiting the cone with the
solids and the remainder staying with the "clean" water.
The hydrocyclone causes the water to become saturated with oxygen - an
average level of 98.6 percent for the 12 sites tested. This finding is significant in the
application of the hydrocyclone technology to areas such as agriculture and waste
water treatment.
The resulting data suggests that the Hydro-Separator is beneficial to water
samples whose dissolved oxygen is below 95 percent. For sites categorized as LOW
oxygen (80 percent or less), sites experienced a mean 27 percent increase in oxygen
content INTERMEDIATE samples (80 percent to 95 percent dissolved oxygen)
showed a mean increase of 14 percent. Samples in the HIGH category (above 95
percent) showed no increase in oxygen saturation. One sample was significantly
higher in initial saturation (137.2 percent), and the action of the Hydro-Separator
seemed to cause an equilibrium effect, bringing the reading close to the 100 percent
level.
Product Quality Variance i
In fungi removal from different test sites, there was a wide variation in the
efficiency of the hydrocyclone, from complete removal of fungi in the "clean" stream, to
only 10 percent removal at one of the sites.
Hydro-Separation believes this variation is due to the difficulty in obtaining
consistent biological samples. For example, the two extremes are related to very low
fungi populations in the feed water samples, so that any effects have extraordinary
weight on the results.
86
-------
Conditions That Impact Performance
A number of process variables, such as pump pressure, underflow orifice size/
percent solids in the feed water, water temperature, and water viscosity (concentration
of clays) could affect the efficiency of the hydrocyclone in destroying or removing
fungi.
Tabulation of Data
Taking TAMU's data and adjusting it to account not only for the concentration,
but also for the relative amounts of fungi present in the FEED, OVERFLOW (OF), and
UNDERFLOW (UF), based on a flow split, where 90 percent is OF and 10 percent is
UF, Table 1 presents a clearer picture of the fate of the fungi.
Table 1. Fungi Removed or Destroyed
T;***'*''.*,
7
1a
2a
9
3
10
11*
12
8*
4
6
5
2b
1b
Total
Mean
,-^frilijMi
400
400
8,300
2,400
4,000
300
400
200
2,400
i.ioo
200
900
300
1,900
23,200
1,657
^,:W«e|>;i
180
180
450
1,260
1,080
90
270
90
1,530
270
0
270
270
900
6,840
489
; '"'fJRtftQKC
0
140
1,200
300
820
30
60
180
340
70
0
70
150
270
3,630
259
' 'S.ttt,
*' '»*'«!&'„ i
180
320
1,650
1,560
1,900
120
330
270
1,870
340
0
340
420
1,170
10,470
748
87
-------
Percent fungi destroyed = (1.657-748) x 100 = 54% of original
1,657
Percent fungi removed from OF (clean water) = (1.657-489) x 100 = 70%
1*657
Percent fungi in UF = 259x100 = 16%
1,657
Percent fungi in OF (clean water) = 489 x 100 = 30%
1,657
*Feed and OF data have been reversed from TAMU report because of sample misidentification.
Table 2 treats the data related to pythium in the same manner as
previously shown.
Table 2. Pythium Removed or Destroyed
< , SH$?K$s<;\
7
1a
9
10
11
12
4
1b
Total
Mean
:;^f^^lSO}v ,j
200
200
100
300
0
0
500
800
2,100
263
-, 3K*fc*\ ,*
90
90
0
0
0
0
180
270
630
79
"v^uF$tHt ; j
0
70
10
0
10
20
30
70
210
26
4, OF*UF ;% .
90
160
10
0
10
20
210
340
840
105
Percent Pythium destroyed = (263-105) x 100 = 60% of original
263
Percent Pythium removed from OF (clean water) = (263-479) x 100 = 70%
263
Percent Pythium in UF = 26 x 100 = 10%
263
88
-------
Percent Pythium in OF (clean water) = 79 x 100 = 30%
263
Usable bacteria data were calculated as shown in Table 3.
Table 3. Useable Bacteria
Site "": '
9
3
6
5
2a
1b
Total
R»e6{Kt$*: J
614
536
45
49
327
427
1,998
^WQP&O^"-
39
271
35
36
15
90
486
% %%\ 5 s''«, ', ? ^&
-«rUF|flMK^~i
5
2
7
2
10
6
32
J. •• ,&',^kf '}' '/v*i
^y<*+tifei
44
273
42
38
25
96
518
Percent bacteria destroyed = M.998-518^ x 100 = 74% of original
1,998
Percent bacteria removed from OF (clean water) = M.99.8-486) x 100 = 75%
1,998
Percent bacteria in UF
36 x 100 = 1%
1,998
Percent bacteria in OF (clean water) = 486 x 100 = 25%
1,998
Cost-Benefit Analysis
As this project did not involve a product or process improvement, quantifying a
cost benefit is elusive.
A 70 percent reduction in plant pathogens does not necessarily mean a
corresponding 70 percent reduction in fungicide use. However, it is possible that less
fungicide would be needed. As plant pathogens develop resistance to the various
fungicides, alternate methods of plant disease control will become necessary;
89
-------
hydrocyclone technology to improve water quality could be a beneficial tool in plant
disease control. Consequently, a reduction in the use of fungicides decreases
fungicide run-off from fields.
While a cost-benefit analysis to estimate the use of hydrocyclone technology to
supplement fungicide use is beyond the scope of this project, it appears that
thousands of dollars from reduced fungicide use could be saved each year. The cost
range for equipment ranges from $10,000 to $50,000 with a payback in 3-5 years.
For example, according to the Golf Course Superintendent's Association of
America, there were 13,004 courses in the United States in 1992 that each spent an
average of over $8,000.00 on fungicide or $104,000,000.00. If fungicide use could be
halved using a hydrocyclone system, the savings in fungicide could average i$4,000.00
per year per course or over $50,000,000.00 for 1992. Projections of fungicide usage
in 1993 are $140,000,000.00, thus the potential savings are $70,000,000.00. This
savings in fungicide costs is in addition to extending the life of the greens by reducing
the amount of silt deposited. Considering approximately half of the 13,000 courses
have silt problems, which require them to replace their greens on an average of five to
ten years, a savings of $25,000.00 to $50,000.00 per year for 6,500 courses would
translate to $162,500,000.00 to $325,000,000.00 per year for the industry.
In addition to the monetary payback is the reduced risk of pollution and health
problems by reducing the use and dependency on fungicides.
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
The hydrocyclone can be used to reduce plant pathogens in irrigation water. A
measure of the actual effects on the health of seeds and seedlings is needed. Does
an immediate reduction of the quantity of fungi in irrigation water allow a significant
reduction in the amount of fungicide applied without adverse effects to the seeds and
seedlings? Controlled, documented studies may allow the application of this
technology to improve yields, reduce crop losses, lessen health hazards, and reduce
fungicide pollution in the environment. !
Industries, such as agriculture, turf, and golf course maintenance, which depend
on irrigation water, would benefit from this technology.
The publicity resulting from Hydro-Separation System's grant spawned a new
Texas corporation, AGKONE. This company uses hydrocyclone technology to
manage wash water from dairy barns that is typically sent to holding lagoons.
90
-------
AGKONE pumps this water through a hydrocyclone before sending it to the lagoons.
The lagoons with hydrocyclone treated water are odor-free, with water quality similar
to stock ponds. The solids removed from the water are also odor-free. The solids
can be used as fertilizer, burned as fuel, or even re-fed after further enhancement.
Hydro-Separation Systems has employed hydrocyclones in such industrial
applications as cleaning foundry and sawmill scrubber water, extending coolant life in
metalworking shops, and removing solids from oil drilling muds. The Company's focus
has recently shifted to environmental concerns, including agriculture wastewater from
dairy, swine, and poultry operations, the aquaculture industry, and irrigation water.
91
-------
MANAGING WOOD PRESERVING WASTE STREAMS
USING THE ENVIRO-CLEAN PROCESS
by
Tom Lewis
Lewis Environmental Services, Inc.
Pittsburgh, PA 15233
ABSTRACT
Lewis Environmental Services, Inc. has developed the ENVIRO-CLEAN
PROCESS, a patent pending process for the reclamation of heavy metals - such as
chromium, copper, zinc, and cadmium - from process wastewater streams. This two
step recovery process utilizes granular activated carbon and electrolytic recovery to
produce a saleable metallic by-product. The process has effectively demonstrated
that it can treat a matrix of multiple metals in a single stream with positive results.
This process can treat waste sources from the wood preserving, metal finishing, and
painting industries.
INTRODUCTION
PROJECT DESCRIPTION
Lewis Environmental Services and Hickson Corporation, a major producer of
wood preserving chemicals, are working together to remediate a growing hazardous
waste problem: copper, chromium and arsenic (CCA) contaminated soil. Currently,
Hickson offers a service to their licensees to dispose of their contaminated soil. It is
anticipated that the cost to dispose of this material will increase dramatically,
impacting Hickson's ability to continue offering this service. The current disposal
technique of stabilizing the contaminated soil by combining it with cement is expensive
and relies on the availability of landfill space.
Lewis Environmental Services proposed managing the contaminated soil using
a two step process. The contaminated soil first would be leached with sulfuric acid to
remove the contaminants. This acid leachate could then be returned to Hickson for
incorporation into the virgin CCA wood treatment bath. In the second step, the soil
would be washed with water to remove any trace contaminants. This secondary
leachate water would then be sent through the ENVIRO-CLEAN PROCESS to capture
the remaining metals. The water could be recycled for subsequent soil washings.
92
-------
Process Advantages
Wood preserving operations gain the following environmental benefits by
utilizing the ENVIRO-CLEAN PROCESS:
1. It allows a wood treating site or chemical manufacturer to perform
closed-loop recovery of valuable chemicals and water.
2. The production and handling of Chromated Copper Arsenate (CCA) treated
wood products generates a hazardous waste in the form of CCA
contaminated soil. This soil is "treated" and reclaimed, eliminating the need
to dispose of the soil.
3. Chromium, copper and arsenic from the initial leach acid are recycled back
into the wood preserving process. The water used to wash the soil is
processed through the ENVIRO-CLEAN PROCESS to remove trace
metals, and the rinse water is used as a source of clean water.
The ENVIRO-CLEAN PROCESS operates in a very simple manner similar to a
filter; the system consists of a tank, pump, and two carbon filters. The system design
and sizing makes it applicable to both small and medium size waste generators. In
addition, the granular activated carbon is reusable and capable of recovering heavy
metals over numerous treatment cycles. Figure 1 is a flow diagram of the ENVIRO-
CLEAN PROCESS. ,
Figure 1. Enviro-Clean Flow Diagram
CCA WASTE STREAM
Cr3> Monitor
93
-------
APPLICATION
Wastes Prevented
The objective of this demonstration project was to verify that CCA contaminated
soil could be successfully processed with a leaching step followed by the
ENVIRO-CLEAN PROCESS. The goal was to develop an acid leaching technique to
sufficiently clean the soil where it would pass the U.S. EPA Toxic Characteristic
Leaching Procedure (TCLP) and be reclassified as nonhazardous waste. The volume
of leach acid with the recovered chromium and copper metals would then be recycled
back into the virgin CCA wood preserving bath. Any rinse water required to clean the
processed soil is processed by the ENVIRO-CLEAN PROCESS. The implementation
of this combined process scheme eliminates the need to dispose of CCA
contaminated soil, which is a hazardous waste, as well as recover valuable metals
such as copper and chromium.
Cross-Segment Uses
This process is directly transferable to other solid waste industries. This
treatment process can be utilized in other industries such as Superfund clean-up,
electroplating, metal finishing, painting, and tanneries. Listed below are some
applications:
1. Superfund: Lewis Environmental Services has received strong interest to
treat chromium contaminated sites with their process in the north-eastern
U.S. These sites contain chromium slag located in industrial, light
industrial, and residential sites.
2. Painting: Waste streams from painting operations utilizing a chromate
phosphate conversion coating. This industry requires the chromate coating
for superior paint adhesion. This technology can help improve this
industry's environmental compliance.
3. Tanning Industry: Raw leather hides are processed with a chromium
sulfate solution. This generates a significant waste volume requiring
treatment and disposal. The recovery of this material may be recycled
back into the tanning operation eliminating waste disposal and possibly
decreasing chemical usage.
94
-------
PROCEDURE
DEMONSTRATION
Soil Cleaning - The objective of this set of experiments was to simulate a four
stage countercurrent leaching operation. Hickson supplied a five gallon container of
contaminated soil which was divided into 5 equal samples. (The number of samples
was limited by economics.) Soil samples weighing 800 grams after screening to
remove large debris and stones were leached with 250 - 300 milli liters of 20 percent
sulfuric acid solution. The second soil sample received the acid that was decanted
and recovered from the first soiMeaching stage; the third soil sample would receive
the acid from the second leaching stage. In basic terms, the "dirty" soil samples were
leached with clean acid. This countercurrent leaching technique yields the maximum
metals concentrations in the smallest volume, of acid. This metals-rich acid is returned
to the virgin CCA wood preserving bath.
The processed soil samples then received a three stage water wash with 300
milliliters of clean water in each stage. The water was decanted and the soil samples
air dried and weighed. The processes soil samples were analyzed for metals and
TCLP testing. The metal levels in the combined water wash sample was 41.1, 94.9,
and 3.0 milligrams/liter for chromium, copper, and arsenic respectively. The soil
samples were air dried and weighed. There was an average soil weight loss of 25-40
percent
ENVIRO-CLEAN Testing ~ Wash water generated from the final cleaning of
processed soil was treated through an activated carbon system. The carbon system
consisted of two filters each containing 180 grams of activated carbon. About 2,000
milliliters of wash water was treated at a flowrate of 15 milliliters/minute. The effluent
was crystal clear. Effluent samples were collected and analyzed for chromium,
copper, and arsenic. Table 1 highlights the results of the carbon treatment test.
Table 1 - Carbon Treatment Data
- '-; ' ," Sample " C" ';:
Feed
30 min.
60 min.
90 min.
120 min.
150 min.
' * * -.^
" " {SferdmTant Qngfo^ ,,
41.1
0.01
0.02
0.01
0.01
0.01
', %00pf»r {jn&g$ -'-,
94.9
0.01
0
0
0
0
•• v 'V.V.V. -. Sr s f >f-.v $ t ""> >
\^J~AKt!&W%f>>S$li \J
3.0
0.22
0.30
0.22
0.17
0.14
95
-------
The carbon has not been regenerated to date, as the volume of solution
processed during the test period was insufficient to perform the carbon regeneration
and electrolytic recovery. Lewis Environmental has regenerated carbon from heavy
metal processes in other applications by treating the carbon with mineral acid to
remove metals from the carbon surface allowing the carbon to be reused. Metals in
the mineral acid can be reclaimed through electrolytic metal recovery (EMR). Thus,
the "lighter" application of soil washing should pose no problems for the carbon
regeneration.
Electrolytic Metal Recovery ~ Electrolytic Metal Recovery (EMR) experiments
were conducted with acid leach solution (which would normally be returned to the
wood preserving CCA bath). 2,000 milliliters of solution was pH adjusted to 3.5-4.0.
A precipitate formed and the mixture was filtered and decanted. The remaining
solution (500 milliliters) was EMR processed under a direct current of 3.5 amps @ 3.5
volts. Experiments ranged in length from 1V6-5 hours. Iridium coated anodes and
stainless cathodes were used. A copper deposit was obtained on the cathode and
removed and weighed. Two EMR experiments yielded recovered metal weighing 0.16
and 0.35 grams. Less than 4 percent of the chromium was deposited. The results
are presented in Table 2.
Table 2 - EMR Recovery Data
\ Sarat^ %
Feed
68min.
128 min.
188 min.
258 min.
^vCii^iiam {*n0$.
1910
1930
1890
1900
1850
V Copper $&g}\)"'
1340
923
960
1020
655
&»es$&twgiffy/
1340
1340
1310
1320
1310
Quality Assurance Controls
Quality control of demonstration tests were performed to current laboratory
standards. pH measurements were checked on a routine basis with buffer solutions
and standard solution checks. Analytical tests for metals were performed using an
Induced Coupled Plasma unit with a Mass Spectrometer for metals analysis. This
provided a high degree of accuracy for metal species analysis. Lewis Environmental
achieved excellent repeatability in the soil cleaning experiments which they attribute to
their quality assurance controls.
96
-------
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
The major objectives outlined for this demonstration project were to:
1. Verify that CCA contaminated soil could be successfully processed with a
leaching step followed by the ENVIRO-CLEAN PROCESS.
2. Develop an acid leaching technique to sufficiently clean the soil where it
would pass the EPA TCLP test and be reclassified as nonhazardous waste.
3. Process rinse waters required to clean the soil with the ENVIRO-CLEAN
PROCESS.
Assessment Summary
All the customer soil samples (5 samples) passed the TCLP test. The two main
leachate constituents, chromium and arsenic, averaged 3.8 milligrams/liter and 1.07
milligram/liter respectively over various TCLP tests. There was an average 25-40
percent reduction in total sample weight after acid leaching. The initial moisture
weight of the soil samples was not determined so this is not a true weight reduction
value. The leach acid analysis from a second stage sample contained 3,330, 13,300,
and 22,990 milligram/liter of chromium, copper, and iron. The water wash solutions
contained moderate levels of chromium, copper, and arsenic; the resulting
concentrations of the combined wash waters were 41.4, 94.8, and 3.0 milligram/liter
respectively. There was consistent repeatability of leaching based on TCLP test
results. All samples passed based on the standardized leach procedure.
Soil Cleaning
This objective was successfully completed. It was demonstrated that CCA
contaminated soil can be acid leached and upgraded to a nonhazardous level. The
acid leaching technique is simple and does not require elaborate equipment design or
process conditions. Lewis Environmental Services utilized sulfuric acid and a
countercurrent processing design to yield consistent, positive results. The reuse of the
acid leachate solution in the CCA wood preserving bath appears to need further
investigation; the presence of trace metals such as iron and aluminum may hinder the
reuse of this solution. More tests need to be completed with the generated leach acid
and analyzed for trace metal constituents. Hickson must determine the acceptable
level of leach acid "contamination" for incorporation into the CCA bath.
97
-------
ENVIRO-CLEAN Processing Results
The activated carbon system processes 2,000 milliliters of wash water
producing a U.S. EPA acceptable effluent based on chromium, copper, and arsenic
levels. The effluent contained on average 0.01, 0.01, and 0.22 milligrams/liter
respectively for chromium, copper, and arsenic. More wash water samples will be
required to perform an extended dynamic carbon column test, perhaps up to 40 to 50
gallons to exhaust the carbon column.
EMR Test Results
The EMR operation is pH sensitive. While adjusting the pH to a range which
would offer efficient electrical operation, the acid leach solution formed a precipitate
which appeared to be copper and chromium hydroxide. Analysis showed that the
precipitate contained chromium, copper, and arsenic; concentrations were 17.5,13.0,
and 56.8 grams/kilogram respectively. A technique for removing the arsenic/iron
precipitate and leaving the remaining metals will be investigated in future research.
The EMR test results showed that copper was preferentially removed over
chromium based on the amounts removed from the feed solution. As the copper
concentration levels dropped, chromium started to be deposited. The copper
concentration in the starting solution was reduced by 50 percent and the chromium
concentration was reduced by 3.7 percent Arsenic levels dropped by 2.2 percent
The metal deposit had a copper color appearance which later turned dark brown
during the later stages of the experiments. More investigative work will be performed
in the area of electrolytic recovery to address the system of operating parameters and
the purity of the metal deposit.
Process Variance
There was no major variations in soil quality in the sample provided. All soil
samples passed the TCLP test without difficulty. The acid leaching technique was
reliable for the batch of soil as supplied by Hickson Corporation. Cost factors
prevented a wider range and number of soils from being tested.
Conditions That Impact Performance
Two major conditions impacted the process:
1. Soil Cleaning ~ Excessive foaming occurred in the first acid leach stage.
This was assumed to be carbon dioxide gas forming from the acid and
limestone present in the soil. The problem was easily solved by using a
larger reaction vessel for the first stage.
98
-------
2. EMR Process -- In the pH adjustment of the acid leach solution, an
arsenic/iron precipitate formed which was filtered out. Additional research
will be conducted to investigate the reuse of this precipitate in the EMR
unit.
Data Tabulation
Table 3 illustrates the soil cleaning analysis from the wood treating industry.
Table 3. Soil Cleaning Analysis from Wood Treating Industry
Chromium
(mg/kg)
6,070.0
58.6
99.03
57,500.0
1,004.0
98.25
Copper
(mg/kg)
4,370.0
221.0
94.94
23,060.0
192.0
99.17
Cost/Benefit Analysis
The driving force for the implementation of this technology is the rising cost for
waste disposal. Based on market figures supplies by the National Environmental
Technology Applications Corporation (NETAC) in their report, Market Survey for the
Enviro-Clean Process, the U.S. CCA Wood Treating Market, prepared in November
1991, reported tiiat there are about 575 sites performing CCA treatment in the United
States. These sites dispose of 1.5-2, 55 gallon drums per month of CCA
contaminated soil. The cost for disposal averaged $200-$500 per drum. This cost
analysis is based on using 400 drums per month with each drum weighing about 600
pounds. If an average disposal cost of $300 per drum is assumed, annual disposal
costs would total $1,440,000 with 2,880,000 pounds of soil disposed.
Based on a total dollar market of $1.44 million, the cost of the ENVIRO-CLEAN
PROCESS to treat the same amount of material can be compared. Based on
laboratory results, 25 pounds of soil can be treated with one gallon of 20 percent acid.
If a plant is designed to process 2.88 million pounds per year, based on a 350 day/24
hours per day operation schedule, 342 pounds of soil must be processed per hour.
Lewis estimates a $500,000 plant cost, with a 3 year payback, yielding an average
cost of $14,000 per month. Operating costs for the plant are estimated at $13,000 per
month, and monthly disposal costs for the soil are $8,600 based on a cost of $100 per
ton.
99
-------
The total monthly operating cost is estimated at $35,600 per month as
compared to $120,000 for soil disposal. The monthly cost to operate this plant and
pay off the equipment in three years needs only 25 percent of the assumed volume or
disposal cost to make this a positive analysis. Also no credit is given for the
recovered metals and positive environmental impact. Lewis conservatively estimates
an additional $400,000 per year of recoverable material. Table 4 outlines the total
cost to run such a plant.
Table 4. Monthly Operating Cost for Soil Cleaning Plant
$500,000 based on a 36 month payback
$14,000.00
Labor, 2 workers @ $150/day each
, 9,000.00
Chemicals - acid @ $150/day
1,500.00
EMR electricity @$150/ day
2,500.00
Total Operating Cost
13,000.00
$100Aon, 70% net weight reduction after cleaning
8,600.00
35,600.00
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
The laboratory evaluation phase is completed for the soil cleaning tests. A field
demonstration has not been conducted because additional soil handling equipment is
needed.
Wood Industry interest seems high. The two largest CCA producers have
expressed an interest in joint venturing a central plant to process the CCA
contaminated soil. Remediating CCA contaminated soil will eliminate the soil disposal
problems of over 600 wood preserving operations in the United States, the majority
being small and medium size waste generators. Also, significant quantities of heavy
metals could be recycled back into the manufacturing process.
100
-------
Limitations
More work may be required in the EMR area to better utilize the acid leachate
solution and to verify if the acid leach solution can be recycled back into the process
formulation.
The EMR needs improvements in the pH adjustment step. The precipitate was
very high in metals, and further investigation is required to enhance or eliminate the
precipitate formation. Lewis plans to further develop the technique to increase the
metal concentration of the leach acid. Current concentrations of 2-3 grams/liter is
borderline for electrolytic recovery. An order of magnitude increase in concentration is
desired. It is expected that chromium recovery will require additional EMR steps.
Arsenic recovery requires different reclamation techniques and must be further
researched.
101
-------
MEMBRANE TECHNOLOGY FOR POLLUTION PREVENTION
IN A ZINC CASTING TUBBING OPERATION
by
Kristen Whelan
Miniature Casting Corporation
Cranston, Rl 02920
ABSTRACT
This manufacturer of precision miniature zinc die-castings proposes to
demonstrate the effectiveness of membrane technology, namely nanofiltration, to
decrease reliance on sewer discharge for wastewaters generated from zinc casting
tubbing operations. The project demonstrated nanofiltration membrane.technology to
recycle water for reuse in the manufacturing process, and recover the aqueous based
cleaner that is substituted for mineral spirits commonly used in the industry.
INTRODUCTION
PROJECT DESCRIPTION
Miniature Casting Corporation Is a manufacturer of precision miniature zinc
diecastings utilizing a tubbing/vibratory operation, common in many manufacturing
industries, especially the electroplating industry. The company sought to reduce their
various waste streams - including zinc waste and waste water - through the use of
membrane technology. Elimination of 60,000 gallons per year of metal-bearing
wastewater and recovery of zinc for recycling are among the results of a successfully
reconfigured zinc casting operation.
Before the project was initiated, all process water was discharged into the
sewer system through ten micron cartridge filters. Two hundred to three hundred
gallons per day of vibratory waste solution had been diluted with approximately one
thousand gallons per day of non-contact cooling water. Hydrochloric acid (HCI) had
been used only occasionally when necessary to pH-adjust the solution. Mineral spirits
had also been used to preclean heavily contaminated parts. Figure 1 shows the
original plant operation prior to implementation of process modifications.
102
-------
Figure 1. Original Plant Operation
occasional HCl
soap
40 gals/month
r \
Tubb
Open
finished
product
-10 tons/month
tap vtter
200-300 gal/day
'- u. ]
ing
itibn
* . ..
P7!
*'-
monthly change
\ /
- 1 ton/me
'reclean r
- 9 tons/month
)nth. \
non-cont
cooling i
-l,000g
^
Die Cast
Operation
to sever
•* -1,200 gal/day
act
rater
al/day
- 10 tons/
x month
Zinc alloy
While original objectives had relied on the use of acids and filtration methods to
minimize waste discharges, development, testing, and improvements obtained during
the year long project indicate that acid is no longer needed and the need for
membrane filtration is much less than originally anticipated. Figure 2 shows the
modified tubbing line.
Figure 2. Flow Scheme for Vibratory Recycle After the Year-long Project
tsp vtier make-up for evap.
-20 gal/month I
soap
- 3 eaVmonth
finished product
Tubbing
Tubbing
Solution
Recycle
ag
bion
Zn die-casts
/
(every 6 veeJu)
as
Periodic sludge
removal for off
site reclamation
(every 6 veeks)
Membrane
100(t Filter
103
-------
APPLICATION
As the demonstration project progressed, additional pollution prevention
opportunities - as compared to the original objectives - became apparent. These
included:
1. The elimination of HCI to settle and remove sludge. Less sludge is created
without the addition of acid, as opposed to conventional chemical treatment
technology where pH adjustment chemicals and flocculants are constantly
used. The treatment chemicals themselves contribute to the overall sludge
volume.
2. The elimination of 60,000 gallons per year sewer discharge of metal
bearing waste water.
3. Water conservation through process and non-contact cooling water reuse.
Additional pollution prevention benefits were also realized:
1. The elimination of mineral spirits to preclean parts by; this was
accomplished by utilizing an increased strength of a caustic,
aqueous-based soap.
2. The recycling of aqueous based soap.
3. The recovery of zinc metal for off-site recycling.
The only filtration needed is for occasional make-up water that is generated by
the membrane system. Except as a prefilter for the membrane, cartridge filters are no
longer used, and the rinsing step has been eliminated. Microfiltration, ultrafiltration
and nanofiltration membranes have been demonstrated to clean spent vibratory
solution for the make-up water.
Membrane technology, a purely mechanical means of separation, has been
demonstrated to be a powerful pollution prevention tool for toxic solvent degreaser
replacement. Membranes have been successfully demonstrated in many companies
to clean and recycle aqueous cleaners, thus reducing pollutants and costs even
further.
104
-------
PROCEDURE
DEMONSTRATION
The objective of the year-long program was to minimize waste generation and
discharge with membrane technologies. The project was divided into three Phases:
1. Ultrafiltration (UF) membrane technology with HCI and citric acid used for
, sludge settling (1/91-6/91).
2. Nanofiltration (NF) membrane technology with only HCI used for sludge
settling (7/91-11/91).
3. Simplified process using NF membrane technology without any acid use
(11/91-3/92).
The flow schemes for each Phase are shown in Figures 3 and 4.
Figure 3. Phases 1 and 2 Flow Scheme for Vibratory Solution Recycle
Tubbing
Solution
Rccycl*
m M. «„_.. « Weekly Staite Removal
Weekly Sludge Removal for Off Site Reclamation
for Off Site Reclamation
105
Membrane-
100(1 Filter
-------
Rgure 4. Phase 3 Flow Scheme for Vibratory Solution Recycle
Eliminate*
Solution
JUcycl*
\
I0n Miter
Eliminated
Membrane
Stodge Removal for
Off Site Reclamation
(every 6 veeto)
In Phase 1, two alternating tanks were used for recirculation of tubbing solution
(pH of around 11) through 10 micron cartridge filters with the other used for settling
out the solids with acid. The best solid settling characteristics were observed at a pH
of 9.7, and solids could be removed through pH adjustment with acid. Approximately
every two weeks, one tank would be isolated from the production loop and treated
with acid while the other tank would serve as the tubbing solution holding tank. The
tank that was treated with acid would then contain the settled solids. The clear upper
water layer was transferred to the membrane process tank, and the sludge scooped
into filter bags for drying. For two months, HCI was used; citric acid was used for the
following two months.
The recycled tubbing solution, albeit effective in cleaning, became very dark as
it was continuously recirculated through the 10 micron cartridges. During the two
month period when HCI was used, no unusual problems occurred in the tubbing and
recycling operations. Zinc tests on the UF permeate revealed low parts per million
(ppm) levels of zinc.
106
-------
In order to reduce the amount of hazardous materials in the operation,
non-hazardous citric acid was tested. While preliminary results with citric acid
appeared satisfactory, a build-up of slimy suspensions and solids made it difficult to
remove sludge from the system. Slime also collected on top of the membrane module
which could clog membrane flow channels and reduce flow rates. Miniature Casting
suspects that the chelating properties of citric acid in the closed-loop system resulted
in high concentrations of zinc chelate, which contributed to the slime build-up. Zinc
tests on the UF permeate from this phase revealed very high solubilized zinc levels
(almost 1,000 ppm). This high reading was attributed to the chelating action of citric
acid and possible interferences in the test method from build up of other minerals in
the permeate.
At the end of Phase 1, all the solution that had been treated with citric acid was
processed with a nanofilter, the effluent sewered, and the sludge concentrated. This
step was necessary to remove citric acid from the operation and continue to the next
experimental Phase.
In Phase 2, NF with HCI, two process changes were introduced:
1. A NF membrane was used instead of a UF membrane to generate
rinsewater.
2. Only HCI was used to pH adjust the fluid. Rlter cartridges were changed
twice per week. .
•i
Sludge was collected through filter bags and sent to the zinc supplier for
smelting and reclamation.
The final phase, NF without acid, was conducted to further simplify the process.
The 10 micron filter cartridges were eliminated from the recirculation loop.
Approximately every three weeks, sludge was manually removed from the tanks, dried
in filter bags, and shipped to the zinc supplier with other scrap metal from the
operation. The rinsing step was also eliminated. The membrane system was used
only to generate make-up water for the closed-loop operation. When the sludge was
removed, the spent solution was dumped into the membrane process tank and new
solution made up with membrane permeate.
In all Phases, the cleanliness of the parts were monitored in-house through
qualitative visual and physical examinations. In general, cleanliness standards -
dictated by the application of the zinc parts - are set by the customers.
107
-------
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
Implementation of this simplified process was successful. A summary of the
results may be seen in Table 1.
Table 1. Summary of Project
fwwi
1'
II 2f
1 3-
II
lii C*
11
II **•
\vto*
1*
N o
H
I 3.
PrW
1.
II 9
II
3.
riruit«a^i^*^in^^A^'^
< ^"-^A^^^^— x'$- ^ *
Mineral spirits eliminated
Ten micron filters used to clean
recirculated vibratory solution
HCI used to pH-adjust recycled solution
once per week from 1 1 to 9
Citric acid used to pH-adjust recycled
solution once per week from 1 1 to 9
Uttrafiltration used to generate rinse
water
Nanofiltration used to concentrate and
dispose of citric acid-laden water
*g H^fesof libpr^ -> :/ ^v^*
Ten micron filters used to clean
recirculated vibratory solution
HCI used to pH-adjust recycled solution
once per week from 1 1 to 9
Nanofiltration used to generate rinse
water
>$'&': N8fl$fP&^$ft''V$&0&$ Acf$ » f*r&£$$&.3»
Acid use eliminated
Ten micron cartridge filters eliminated
Rinsing step eliminated
;^:v;* '^r>^:Jv:^\^?"lVr
s * v* ^- ^ui^^rv^i^rV';;,;1/ - - :
Stronger soap concentration used to clean more
heavily contaminated parts
Solution reusable; filters changed twice per
week '
Good sludge settling; however, HCI is a
hazardous material
Good sludge settling; however, even though
non-hazardous, citric acid created slime build-up
and rendered the operation labor-intensive
Adequate rinsing results; 20-30 gallons per day
of permeate required
Necessary to clean system for next phase
" r ; >~ , ^ ' ^ *. ..**...*.« ~..±.^^.1.
Solution reusable; filters changed twice per
week
Good sludge settling; however, HCI is a
hazardous material
Adequate rinsing results; 20-3- gallons per day
permeate required
fci*8«&i6*~'^K ^x" ^ \''":v-V/i ' . ' , :; ; i
Solution reusable for approximately 6 weeks;
HCI no longer required; less sludge generated
Solution reusable for approximately 6 weeks;
filter costs lowered
Parts cleaner without rinsing; membrane system
used 90% less; permeate used for make-up
water approximately every 6 weeks |
108
-------
Rinsing Step Elimination
UF was used in Phase 1 to generate clean rinsewater which adequately
cleaned the zinc parts. Since NF pores are smaller than those of UF, the permeate
was even cleaner, and as found in Phase 2, also adequately cleaned the zinc parts.
While the product rejection rate was acceptable with membrane permeate used as
rinsewater, it was observed in Phase 3 that an even lower rejection rate could be
obtained without rinsing the soap solution. It is hypothesized that the solid fines from
the vibratory operation exhibit greater adhesion to the plastic and ceramic stones (in
the vibratory tub) without rinsing. As soon as "clean" rinsewater is introduced, some
adhesion loss occurs and the metal parts become tainted. The chemistry of the
solution may have also changed because acid was no longer used, possibly affecting
the solid adhesion characteristics. The solution appears black/gray, probably due to
metal oxidation. Despite the dark color, the solution cleans very effectively.
The elimination of the rinsing step has reduced the operation of the membrane
system from approximately 500 gallons per month to less than 50 gallons per month,
greater that 90 percent reduction. Because the weekly acid addition was eliminated,'
the solution could be recirculated longer. The 10 micron filters were eliminated when
it was observed that filtering had no effect on product quality; using cartridges only
served to unnecessarily increase operating costs. In addition, less caustic soap is
used to "charge" the solution since acid is no longer used. Thus, the unfiltered soap
solution only can be reused for up to six weeks due to the solution's inability to
properly clean parts. (This is likely attributable to the solids build-up.) At the end of
the six week cycle, the tanks are emptied into the membrane process tank, settled
sludge is removed, and clean water from the membrane system is used for make-up.
Acid Elimination
Citric acid, a known metal chelator, appeared to create a slimy build-up on the
filters and piping, rendering the operation somewhat labor intensive. Even though
citric acid is non-hazardous, and therefore preferable, the operation became
unacceptably tedious. In order to prove the hypothesis concerning citric acid and
slime build-up, HCI was reintroduced for use in Phase 2; HCI has also been
successfully used in Phase 1 prior to the testing of the citric acid.
During Phase 2 - with HCI - no slime build-up was observed. While the solution
had been filtered and disposed at the end of Phase 1 to remove citric acid, no such
step was taken at the end of Phase 2. Phase 2 fluid, where HCI was used, was
carried over into Phase 3 where no acid was used.
/
One of the objectives of Phase 3 was to determine the effect of eliminating acid
from the entire operation. As expected, more solids remained in suspension.
Nevertheless, product quality did not suffer and improvements have been noted. It is
109
-------
not known which of the factors in Phase 3 has caused the zinc parts to be cleaner:
the elimination of the rinsing step; or the elimination of acid use and cartridge filters
which leaves more solids in suspension. Perhaps it is a combination of th© two.
Sludge samples were analyzed for metal content and compared as shown in
Table 2.
Table 2. Sludge Analyses (Total Metals)
Aluminum
15,600
16,500
18,900
Cadmium
3.5
1.6
Copper
938
398
1,090
Lead
85
44
32
Zinc
135,000
144,000
16,800
Except for zinc, the relative percentages of metals varied little in relation to the
type of acid used (HCI or citric) or lack of acid. Less sludge was removed in Phase 3
when no acid was added; more zinc solids remained in suspension, thus decreasing
the amount of sludge created. All sludge, along with scrap metal, was sent to the
metal supplier for reclamation. ,
Additional Pollution Prevention Accomplishment - Mineral Spirits Elimination
In Phase 1, it was discovered that heavily contaminated zinc parts that were
once cleaned with mineral spirits could now be cleaned with a stronger concentration
of the caustic aqueous soap, Oakite M3, at a pH around 11. The sewer discharge
limitations for pH (10.0) and zinc (1.0 ppm) were not factors in the process when
recycling was implemented. Cooling water is recycled so that no discharge
whatsoever is taking place, thus the aqueous soap can successfully replace the
mineral spirits.
Product Quality Variance
Overall, product quality did not suffer throughout the project. In Phases 1 and
2 occasional "pitting" of the zinc parts was observed. It was determined that this was
due to accidental overuse of the caustic soap; more controlled procedures corrected
the situation. In Phase 3, the rejection rates of zinc parts actually decreased as
compared to before the start of the project when no soap and water were recycled, as
well as during Phases 1 and 2. !
110
-------
Cost/Benefit Analysis
Table 3 compares the direct cost of the present (1992) recycling operation with
the old non-recycling operation (1990). Not included in Table 3 are costs incurred by
the test program itself (e.g., subcontractor and test costs). Also not included are
savings obtained by increased productivity which resulted from fewer rejected lots of
product and less rework of dirty product.
Table 3. Economic Analysis of Vibratory/Cleaning Operation
Y^rf*AJ'#«t*fe«**i*' - ''",'?'* W"V""" ', ' ;
i^a|HtE8 fci$|wlpflfw{ » g ,. , ' •f^,'- St:"' ' • '«•
Membrane system
Tanks
Pumps
Filers/housings
As^^*4afeel,'''H
$5,500
(Anticipated)
$100
0
400
300
negligible
1,700
0
0
0
$2,500
$9,157 - $2,500 = $6,657
l^bafifc., ^^<#5£^x* ysar*^ |
111
-------
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
The project has demonstrated success in the recycling of vibratory solution in
the zinc die-cast industry. A second company which also manufactures zinc die-cast
parts has already directly benefitted from this project and has been successfully
recycling with no sewer discharge for nine months. Similar test programs at other-
Rhode Island facilities have begun. While the vibratory/tubbing operation is
ubiquitous, many parameters exist which render each individual operation unique. The
type of metal to be cleaned, the type of soap used, the desired finish on the metal, the
type of vibratory media used, and even the incoming tap water supply all have to be
considered.
Barriers
While the economic analysis displays a favorable payback, the figures do not
include EPA grant funds that paid for employee time, consultant work, and
supplemental analytical tests. Total project cost may prohibit other companies from
implementing such technologies. However, it is anticipated that date obtained from
this project will facilitate programs at other companies such that developmental work
and costs are minimized.
A hydrocyclone was tested near the end of the project to facilitate the
separation of the zinc particulates from the solution more conveniently than in the
present operation where manual labor is required to remove the settled sludge. Initial
results indicate that this direction will be beneficial.
112
-------
ELIMINATING WASTE DISCHARGE
IN A REEL-TO-REEL ELECTROPLATING SHOP
by
Kenneth Marino
Orbel Corporation
Phillipsburg, NJ 08865
ABSTFWTT
Orbel Corporation, a reel-to-reel electroplating facility, implemented several
source reduction practices to reduce water usage. Wastewater remaining after source
reduction was processed to reclaim metals and oils, and purified to produce water of
the high quality needed for reuse in the reel-to-reel electroplating process. Similar
systems have been successfully employed in the rack and barrel segments of the
electroplating industry, however the reel-to-reel process requires a higher quality waiter
supply. This project is intended to demonstrate both the technical and economic.
feasibility of eliminating wastewater discharge to the POTW through source reduction
practices and waste rinse water treatment for process reuse.
INTRODUCTION
PROJECT DESCRIPTION
Orbel Corporation is an electroplating company specializing in plating strip foil
and reel-to-reel piece parts. Clients include both commercial and military customers.
A 45% reduction in hourly water use and the elimination of zinc from wastewater have
been realized by Orbel Corporation in their reel-to-reel electroplating operation.
In the process of electroplating, the use of clean water is critical. The goal of
this project was to implement a system to purify contaminated water from the plating
process and return the water to the plating line. Metal, salts, and oils are removed
from the water, and contaminants are addressed separately to render them easily
recycled.
113
-------
PROCEDURE
This project involves the logical management of the plating line process witriout
the use of complex and expensive equipment. It was the result of ideas generated at
Orbel's weekly production meeting. Several days were required to implement the
suggested changes. System refinements were conducted over the following three to
four weeks at which time satisfactory data were obtained. Two key methods were
implemented to the process depending on the contaminant in the plating cell prior to
rinsing. '. '
1. Plating tank rinses were modified into three rinse stations, cutting water
flow by 95 percent. This water flow is small enough to allow all rinse water
to be circulated back into the plating tank.
2. Following the cleaner and acid tanks, water is counterflowed from the acid
rinse to the cleaner rinse. This permits management of the water within
the plating line.
Figures 1 compares the original and modified plating cells; Figure 2 compares
the original and modified cleaning lines.
APPLICATION
The introduction of counterflow rinsing into the plating line has many
advantages.
1. Caustic consumption was reduced by 7,000 pounds per year and
eliminated acid for waste treatment
2. With the reduction of water consumption, additional time Is available to
manage the wastewater.
3. Counterflow into the nickel plating tank has completely eliminated nickel
from the waste stream.
Water is considered a renewable resource within the plant, and a number of
materials may be recovered from the wastewater. Metal is recycled through a local
metal smelter. Oils will be utilized as fuel at a licensed facility. Salt water is the only
true waste product, and is sent to a deep well facility for treatment and disposal.
114
-------
Figure 1. Plating Cells: Comparison of New and Old Systems
Plating Cells
Old System
Nickel Plating Cell
Nickel
Sump
Product Row
1GPM
Fresh
Water
Rinse
To Waste
Treatment
16 hours of operation per day
Per Hour Per Day Per Week
Old System
New System
60 G
960 G
4,800 G
00 0
Yearly water savings 249,600 gallons
Plating Cells
New System
Nickel plating cell
Nickel t
Sump
"
^
Rinse
J
^
F
1
1
/50HP
'ump
No was
p.'
Rinse
2
q
tewater to
1
1
1/50
Pum
dra
HP
p
n
^~
Fresh
1 Water
A. {
Rinse
1
1 1/sn HP
Pump
Product Flow
115
-------
Figure 2. Cleaning Lines: Comparison of New and Old Systems
Cleaning Line
Old System
Cleaner
Water
Rinse
I
To Waste
Treatment
Cleaner
Product Flow
1 1 GPM
Fresh
Iwater
Rinse
_ «/«,«.«-
To Waste
Treatment
Acid
1 GPM
Fresh
Water
Rinse
To Waste
Treatment
Cleaning Una
New System
1 Cleaner 1
"
Rinse
i
1
1
r
oWasU
"reatmer
1
J
1/50 HP
Pump
j
it
Cleaner
: : —•»•
Product Row
~X
Rinse
c;
i_
Acid
j
Pump
^L,
Rinse
C
1/2
GPM
Fresh
Water
1/50 HP
Pump
1 6 hours of operation per day
Per Hour Per Day Per Week
Old System
New System
180 G
30 G
2,880 G
480 G
; 14,400 G
2,400 G
116
-------
Similar process changes may be easily implemented in metal
operations. In addition, this basic "rethinking- of process fnanMemen
pollution prevention is applicable to almost any industry. Such process
changes 'mplemented at '°W Cost to the comP^ ^require no major
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
were applied to determine the success of the process
Table 1. Water Test Summary
: Standard for
Table 2. Water Consumption
Sept-Nov. 1991
6,821 running 24
hours
284
NJ NPDES Standard*
8,281 running 16
hours
1,705,250
117
-------
top of the tank.
Host/Benefit Analysis
Table 3. Cost Comparison of the Old and New Systems
" •~
...Nil I I ' •"-
CompHance Testing
Water Purchases^
Sewer
—n. •• —
Electricity
————
Labor
—
Treatment Chemicals
Maintenance/Repairs^
a i
ANNUAL TOTAL
Old System ($)
1,820.00
~
4,037.00
—i
4,900.00
'•
16,800.00
—,
7,488.00
_
5,000.00
—
9,300.00
"-
49,345.00
New System
—ii i --•
1,820.00
1,816.65
__..
2,205.00
• ii 'I.—
16,800.00
—..
6,500.00
2,000.00
—
10,500.00
_—.————•
41,641.65
118
-------
Similar process changes may be easily implemented in metal finishing
operations. In addition, this basic "rethinking" of process management towards
pollution prevention is applicable to almost any industry. Such process changes may
often be implemented at low cost to the company and require no major technology
changes.
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
Simple test parameters were applied to determine the success of the process
changes. Nickel, copper, and zinc levels, and water consumption were measured as
shown in Tables 1 and 2.
Table 1. Water Test Summary
NJ NPDES Standard*
September 1990
September 1991
October 1990
October 1991
November 1990
November 1991
Nickel (ppm)
2.38
.05
.05
.21
.05
.74
.10
Copper (ppm)
2.07
.38
.63
.43
.40
1.10
.21
Zinc (ppm)
1.48
.13
.032
.10
.013
.25
.19
*New Jersey National Pollutant Discharge Elimination System: Electroplating Effluent Guidelines,
Pretreatment Standard for Existing Sources Greater Than 10,000 Gallons Per Day
Table 2. Water Consumption
Sept- Nov. 1990
Sept -Nov. 1991
Daily (gal.)
8,281 running 16
hours
6,821 running 24
hours
Hourly (gal.)
517
284
Yearly (gal.)
2,070,250
1,705,250
117
-------
Water consumption was measured via the plant water meter. All water in th®
plant is controlled by one switch. Since the plant operates the same number of hours
each day, water consumption is consistent as daily water flow is started and stopped
by one switch at approximately the same times. Figures shown represent a 45
percent reduction in hourly plant consumption of water.
Upon implementation of the changes within the plating line, spotting and
oxidation of the work pieces were noted. When the volume of water was reduced in
the tanks, chemical concentrations increased. Agitation of the water in th© final rinse
cells evenly distributed the chemicals throughout the tank without the need for
additional fresh water. Also, agitation dispersed and settled the layer of "scum" on the
top of the tank.
The materials which are being separated from the wastewater do have potential
value. However, due to the complex nature of waste regulations and the small
amounts of materials generated, no income has been realized as yet from the
reclaimed materials. Table 3 compares costs for the old and new systems.
Cost/Benefit Analysis
Table 3. Cost Comparison of the Old and New Systems
Compliance Testing
Water Purchases
Sewer
Electricity
Labor
Treatment Chemicals
Maintenance/Repairs
ANNUAL TOTAL
Old System ($)
1,820.00
4,037.00
4,900.00
16,800.00
7,488.00
5,000.00
9,300.00
49,345.00
New System ($)
1,820.00
1,816.65
2,205.00
16,800.00
6,500.00
2,000.00
10,500.00
41,641.65
The old system used city water delivered under pressure. The new system, which
recircujates water, must have its own pumps. The increased maintenance costs in the
new system are attributed to the repair cost of these pumps.
118
-------
CONCLUSION
POLLUTION PREVENTION ASSESSMENT
While an ideal goal of zero discharge to the sewer system was not realized,
many positive changes were implemented within the plating line. These process
changes will be further refined; however, present modifications can be easily
implemented in other plating and metal finishing operations.
A major challenge to this project is the management of dissolved solids in the
water which can hinder water reuse. Short term solutions include the use of sand and
carbon filters to allow additional water cycles within the line prior to discharge. While
these filters generate solid waste that requires disposal, Orbel is investigating the
regeneration and reuse of the.filters.
119
-------
IN-FIELD, ON BOARD, DRY GRANULAR
HERBICIDE IMPREGNATION
by
John Brodman
Walton Agri-Service, Inc.
Upper Sandusky, OH 43351
ABSTRACT
Walton Agri-Service, an independently'owned and operated agricultural supply
business demonstrated and evaluated the effectiveness of a new technique of
chemical herbicide application involving the use of dry granular herbicides in
conjunction with dry fertilizer. Dry herbicide application holds promise to be a cost
effective, environmentally sound improvement over the current practice of applying
liquid herbicides in a water solution. Dry chemical application can be controlled to
reduce over-application, unused chemicals can be readily stored, and spilled material
can be easily recovered and reused. The economic advantages of combining
herbicide and fertilizer applications in a single pass over a field was also
demonstrated.
INTRODUCTION
PROJECT DESCRIPTION
Outline of Process
In-field, on board dry granular herbicide impregnation involves ©quipping a
pneumatic fertilizer spreader with separate bins and metering devices to apply dry
granular herbicides along with dry fertilizer.
Walton Agri-Service retrofitted a 1990 model 1603 Terra-gator Air Spreader
manufactured by Ag-Chem Equipment Company of Minnetorika, MN. The Air
Spreader is a self-propelled off-road vehicle designed to use the air stream from two
hydraulically driven fans to evenly spread an application of dry fertilizer across the
width of the sixty foot wide boom mounted on the rear of the machine. A dry granular
metering system along with a Raven SCS 700 control console (also from Ag-Chem
120
-------
Equipment Company) was installed on the Air Spreader.
The granular unit consists of two herbicide boxes, each with 1,000 pounds
capacity, designed to be mounted on the rear of the Spreader. In the bottom of each
box is a set of metering wheels driven by separate 12 volt DC current, variable speed
motors. The Raven control console mounted in the cab regulates the speed at which
the metering wheels dispense the dry herbicide, based on vehicle speed and
pre-determined application rates. From the metering wheels, the herbicides drop onto
the dry fertilizer stream leaving the fertilizer box. Together, the two dry chemicals are
carried up a vertical auger to the distribution head, where the air stream carries both
materials through the booms and onto the soil. The result is an even spreading of
particles onto the fields. Figure 1 shows the Air Spreader operating in the field.
Figure 1. Air Spreader
121
-------
Unique Product Features/Advantages
Dry chemical application has a number of advantages over traditional liquid
applications:
Spills are easily handled.
Employee exposure is reduced, as all blending and tendering of herbicide
and fertilizer is done mechanically in the field.
Residue in plant blending equipment is eliminated.
Plant odors are minimized.
Potential for over-application of chemicals is reduced, as application can be
made precisely according to soil type and weed pressures.
Disposal of left-over impregnated fertilizer granules is eliminated.
Rinsate disposal is minimized.
APPLICATION
Process/Products Replaced
Most liquid agricultural chemicals are applied by first diluting with water or liquid
fertilizer; this mixture is then sprayed onto fields requiring treatment. Handling of liquid
herbicide solutions present several environmental concerns:
When a tank load of herbicide solution for a given field is mixed, some
liquid herbicide is usually left over after treating the field. If the next field
calls for a different chemical mix, the leftover solution must be returned to
the plant for storage until it can be reused. When changing herbicides or
the crop to be treated, the tank, pump, hoses, and booms on the
application equipment must be cleaned and rinsed. The rinsate contains
dilute amounts of herbicides which also must be stored until applied to a
field. In Walton's high volume operation, storage and management of
leftover herbicide solution and rinsate can be problematic.
Because liquid herbicide solutions are applied to fields under pressure, a
certain amount of fine spray particles can drift off-target.
122
-------
Even though liquid herbicides are stored in tanks enclosed by dikes, and
in-plant loading of herbicides is done on a concrete pad designed to catch
and contain spills, the possibility of spills is present. Cleaning up a liquid
spill is difficult, and any contaminated soil must be removed.
The seasonal nature of the herbicide application business requires the
storage and handling of large volumes of chemicals over a brief time span.
At the end of the season, Walton's 40 mini-bulk liquid herbicide tanks and
associated equipment must be cleaned and rinsed, thus creating additional
rinsate to dispose.
Wastes Prevented
During the project, Walton Agri-Service used the in-field, on board dry granular
herbicide impregnation technique on 3,405 acres (77 fields) with 44 farmers and
landowners participating. On these acres, 57,740 pounds of dry granular herbicide
was applied with an average application rate of 16.96 pounds per acre. The dry
herbicide replaced 2,165 gallons of liquid herbicide. As with any applied herbicide,
rainfall or irrigation is required to efficiently dissolve and carry the herbicide through
the soil. Although the herbicide in the project was dry, no additional water was
required to carry the chemical into the soil (as compared to liquid herbicide).
Water savings realized through the use of dry granular herbicides was as
follows:
3,405 acres x 20 gallons water per acre not required = 68,100 gallons
water
77 fields x 50 gallons water / load rinsate & rinsewater not required = 3,850
gallons
Total water saved = 71,950 gallons
No leftover liquid herbicide needed to be stored or reused, and no rinsewater or
rinsate was generated.
While no herbicide was spilled during the project, spilled dry herbicide could be
easily swept or vacuumed for recovery and reuse.
Cross Segment Uses
Industries which use or apply liquid chemicals may find a dry alternative.
Simplified storage of dry chemicals (in bulk or sacks) and reduction of water use may
result.
123
-------
PROCEDURE
DEMONSTRATION
Three objectives were established for the project:
1. Evaluate the storage, handling, transportation, and application equipment
required to handle and apply dry granular herbicide.
2. Demonstrate to customers, other applicators, and other interested parties
the environmental benefits of dry versus liquid herbicides.
3. Evaluate the overall performance and cost effectiveness of dry granular
herbicides.
Storage and Handling
At the onset of the project, DuPont's Extrazine II dry granular herbicide was
planned to be purchased in 1,000 pound mini-bulk sacks and managed by a sack
handling system developed and marketed by Murray Equipment Company to empty
the sacks into the herbicide bins on the Air Spreader. During the course of the
project, the 1,000 pound sacks were discontinued by the manufacturer. A shift to
Monsanto's CropStar was made, and due to the large volumes of material to be
handled, Monsanto offered to install a bulk hopper bottom storage tank specifically
built to handle CropStar. The bulk tank holds 100,000 pounds in an enclosed system
designed to accept delivery from pneumatic unloading trucks and incorporated an air
return and filtering system to contain herbicide dust generated during the unloading
process. From the storage tank, CropStar granules are elevated through a closed 6"
diameter auger into the herbicide boxes on the Air Spreader.
Bulk handling of the granules eliminated the handling and disposal of the
mini-sacks, and operator exposure to the herbicide was mostly eliminated, as the
system is almost totally enclosed. Rgure 2 illustrates the tank model for storing and
handling the bulk herbicide.
124
-------
Figure 2. Tank Model
ENVIRONMENTAL ADVANTAGES VS
IN-PLANT IMPREGNATION
• Reduces employee exposure
- No in-plant mixing, less clean out
« Closed system handling from delivery to application
*
•»
•»
-*•**•»•*«•*•*•* ±4 *«*.«..«.«*«
Transportation
Original plans called for the purchase and installation of a hopper bin on a
fertilizer delivery truck to deliver the CropStar and fertilizer to the Air Spreader
operating in a field. Problems in the hopper design delayed delivery until too late in
Walton's use season.
Other transport systems are being investigated to eliminate the need to return
the Air Spreader to the plant for refills.
Monsanto anticipates the availability of a concentrated form of CropStar which
would allow more areas to be treated in a single fill-up.
Overall Performance
To evaluate weed control performance of the dry herbicide compared to a liquid
equivalent, four fields were dedicated to a side-by-side comparison, In each field, half
was treated using dry granules, with the other half treated with a liquid herbicide. All
participating farmers evaluated weed control in the CropStar treated fields with their
125
-------
other fields treated conventionally. Weed control performance using granulated
CropStar was as good or slightly better than in conventionally sprayed fields. Dry
granules tend to fall through any plant residue lying on the field; liquid herbicide
sprayed onto the residue are thus unavailable for weed control.
Daily Workings
At the start of each day, the Air Spreader's herbicide boxes were loaded with
2,200 pounds of CropStar. Fertilizer was also mixed and loaded. Upon arriving at the
field to be treated, the Air Spreader operator entered the appropriate data and
application rate into the control console. After spreading the field, the operator turned
off the metering system, recorded the pounds of CropStar applied as displayed on the
monitor, and proceeded to spread any leftover fertilizer onto the field.
At the next field, a Walton fertilizer delivery truck loaded that field's fertilizer
requirements onto the Air Spreader. For fields not requiring GropStar, the operator
turned off the herbicide metering system, and simply spread the fertilizer.
Using this system, approximately 125 acres could be treated with CropStar
before the Air Spreader returned to the plant for refilling. On an average day,
between 400 and 500 acres could be treated with fertilizer and herbicide.
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
Product Quality Variance
In addition to the outlined application method, Walton also applied 625 pounds
of Extrazine II DF dry flowable herbicide on 148 acres. The Extrazine granules were
added directly to the fertilizer in the fertilizer blender instead of applying it through the
herbicide unit. The fertilizer ingredients in the blender were moistened with 2-4 quarts
of liquid fertilizer per ton of dry fertilizer and blended with the required amount of
Extrazine. The fertilizer and herbicide mixture was spread as if straight fertilizer.
This application method was not as acceptable. The fertilizer blender was
difficult to clean after the blending process. Concern existed over the possible
separation of ingredients during transportation and application. Also, any remaining
mixture needed to be stored.
126
-------
Conditions That Impact Performance
The on-board Impregnation unit performed without major problems.
On one occasion, moisture seeped through a seam on the herbicide boxes and
dampened the CropStar, causing the material to bridge-over and prevent the metering
wheels from dispensing any material. After seams were caulked, the damp CropStar
was allowed to dry and mixed with new material before reuse.
The CropStar is never weighed during handling. Since the metering wheels are
metering volume, any change in flowability or density of the product will affect the
pounds of material actually applied. In addition, the operator cannot know if material
is being dispensed without periodically monitoring the herbicide level in the boxes.
Errors in calibrating the metering unit affect application rates.
Data Tabulation
Project statistics include:
Granular herbicide applied:
— 57,740 pounds CropStar granules over 3,405 acres
— 625 pounds Extrazine II DF granules over 148 acres
Liquid herbicides replaced by dry granules:
— 2,165 gallons liquid Lasso replaced by CropStar
— 142 gallons liquid Extrazine replaced by Extrazine granules
Water saved with dry herbicides
— 68,100 gallons (3,405 acres x 20 gallons/acre)
— 3,850 gallons (77 fields x 50 gallons/field)
— 71,950 gallons water not used
Packages replaced.with bulk system
— 58 1,000-pound mini-bulk sacks
Participating farmers and landowners
— 44
127
-------
Cost / Benefit Analysis
Equipment and start up cost for the in-field on board dry granular herbicide
impregnation technique totaled $21,889.32 excluding labor, cost of CropStar,
insurance, taxes, and cost of the bulk storage tank. Amortized over an expected
useful life of seven years provides an annual cost of $3,127.05. Additionally, 30% of
the original cost - $938.12 - per year is allowed to cover repairs, maintenance, interest
expense, and future updates to the system.
An annual total cost of $4,065.17 divided by an expected 4,500 acres per year
on which the unit will be used gives an approximate cost of $.90 per acre to own and
maintain the system.
Walton presently charges an extra $.50 per acre for applying granular herbicide
along with the regular fertilizer application. Monsanto Company is allowing a rebate of
$.04 per pound of CropStar to help defray the cost of equipment and maintenance.
With an average application rate of 17 pounds per acre, this additional revenue totals
$.68 per acre. Total income per acre is $1.18, less costs of $.90, yielding a $.28 per
acre investment return.
No additional labor charges or costs of owning and operating the Air Spreader
were factored into the previous calculations; costs are similar whether the machine
applies straight fertilizer, or fertilizer and herbicide. Also, profit margin for the!sale of
CropStar was not calculated, as the margin for the sale of an equivalent amount of
liquid herbicide is similar.
While customers are paying an additional $.50 per acre for the granular
herbicide application, they actually save $3.50 per acre. One $4.50 per acre
application pass across a field replaces two separate $4.00 per acre trips for fertilizer
and herbicide applications.
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
This process has proven to be successful in the marketplace. Both custom
applicators and farmers need to increase efficiency in their operations, and this
application method can save time, better utilize equipment, save money, and provide
equivalent or improved weed control and crop performance.
128
-------
The ability to control application rates of both fertilizers and herbicides
according to soil types and fertility levels is a major advantage. Soil need variations
across a field (such as when an old pasture or feed lot is incorporated into a larger
field) can be easily accommodated by changing application rated as the machine is
operated across a field.
The industry is beginning to recognize the importance of this concept.
Agencies and individuals are working towards the best techniques for "prescription
farming" or "farming by the grid".
Barriers
Variations in product density or fiowability affect the actual rate of herbicide
applied. With the bulk system, there is no opportunity to weigh the herbicide, as it is
transferred directly from the storage tank to the Air Spreader. One solution is to install
load cells under the legs of the storage tank such that the weight of herbicide removed
can bet calculated. This would allow confirmation of the impregnation unifs calibration,
monitoring of actual application rates, and improved inventory control.
The present system permits the application of only one herbicide at a time.
Those interested in this application technique may need to use one herbicide for all
situations when an alternative herbicide is preferable.
initial start-up costs for equipment and overhead may be limiting. Each dealer
must eivaluate his situation, mindful of the increased efficiency, additional service
provided, and environmental benefits to be gained by handling and applying granular
herbicides.
The increased technological complexity in the on-board impregnation unit and
the Air Spreader requires a brief period of additional operator training to efficiently
calibrate and troubleshoot the system.
129
-------
WASTE MINIMIZATION IN ELECTROPOLISHING:
ELECTRODEPOSITION AND PROCESS CONTROL
by
Thomas Pierpont, Project Manager
Allen P. Davis, University of Maryland, Principal Investigator
Pier-Sol, Inc.
Baltimore, MD 21222
ABSTRACT
Electropoiishing is the process of passing a current through a metal work piece
that removes a thin layer of the work piece and produces a bright, corrosion resistant
finish. This process results in the release of iron, nickel, and chromium from the work
piece to the acid bath. A stainless steel electropolisher proposes to develop an
electrochemical process to recover these metals from the electropolishing acid bath
thereby prolonging the life of the acid bath and decreasing sludge production. The
metals will be plated onto an appropriate electrode in the metallic form. Initial
development work will be conducted on the laboratory scale, and then demonstrated
on an actual electropolishing acid bath in a working situation.
INTRODUCTION
PROJECT DESCRIPTION
Electropolishing is the process of passing a current through a metal work piece
- in this project, stainless steel - removing a thin layer of the work. Metals are
electropolished to produce a bright, corrosion-resistant finish and for efficient
sterilization. During the process, a small portion of the work is oxidized, dissolving the
piece, thus releasing iron, nickel, and chromium. The most effective polishing is
achieved in an acid bath, of which several chemical mixtures are used.
Pier-Sol currently dissolves about 3,800 pounds of stainless steel per year.
The dissolved metal accumulates in the polishing tank until either the depth of
accumulation, or the concentration of metals in solution reduces operational
efficiencies to unacceptable standards. This dense sludge is removed from the
polishing tanks and disposed of as hazardous waste due to its heavy metal content.
130
-------
However, since approximately 23-36 percent by weight of the sludge is
non-hazardous iron, this project concentrated on separating the iron from the acid
bath/rinsewater system to reduce the volume of the sludge and reclaim the iron for
recycling.
Pier-Sol currently operates a primary electropolishing line consisting of an
electropolishing bath mixture of sulfuric and glycolic acids, followed by two dead water
rinse tanks and one spray rinse tank. See Figure 1.
Figure 1. Electropolishing Line
WORK / DRAGOUT
maKe-uo
wwffll'
ileciroDOlishing
3atn
EP2A
SOP gal.
Dead Rinse
EP2B
700 gal.
Dead Rinse
EP2C
400 gal.
Spray rinse
800 gal.
In each tank, daily liquid losses are replenished from the succeeding tank, with
losses from the second rinse tank make up with fresh water. This counter-flow
process creates a closed loop system that builds up metal impurities in the first two
tanks. In fact, the primary rinse tank has been measured at higher concentrations of
iron and copper than the electropolishing bath. Because of the chemical difficulties of
electrodepositing iron under very acidic conditions, this study investigated controlling
metal concentrations in the electropolish bath through management of the primary
rinse tank (which would subsequently be returned to the electropolishing bath).
Following a literature search on the electrodeposition of iron, laboratory testing
of electropolishing solutions were conducted to determine a range of optimal values
for variables considered to be most critical to the electrodeposition of iron: pH, voltage,
and iron concentration.
131
-------
The final phase of the study was originally designed to construct a bench scale
system to measure metal removals under various voltage conditions and plating
durations. However, based on the conclusions of the second phase of testing, the
investigation was redirected towards waste minimization via process control. This was
accomplished by regulating electropolishing time relative to the age of the polishing
bath to minimize the amount of metal removed from the surface of the work piece.
APPLICATION
The successful process change decreased the amount of metal in the polishing
bath, thus increasing bath life. Removal of metal sludge from the polishing tank would
be required only 2.5 times per year - down from 5.5 times per year - which in itself
saves time and labor. Yearly waste disposal costs for the sludge would shrink to
$4,680, less than half the current cost of $10,400,
The examination of process time in relation to the age of process bath and
product quality is applicable to a variety of metals processing operations. In addition,
the counter-flow sequence in the process line is also applicable to metals processing
to reduce water usage and minimize waste production.
PROCEDURE
DEMONSTRATION
In Phase I of the project, a thorough literature review found numerous
references of electrodeposition for iron production, but found no applications of iron
plating to wastewater treatment/metal recovery. Valuable information, however, was
found on industrial iron plating and electrolyte recovery of other metals, plus other
possible treatments for electropolishing baths.
During Phase II, four types of laboratory experiments were conducted to
determine the optimal pH and voltage for plating.
In the first series of experiments, current versus potential curves were
generated for sulfuric and glycolic (hydroacetic) acid solutions with controlled pH and
Iron concentrations. The pH of sulfuric acid (97 percent) was adjusted to 0, 1, 2, and
3 by dilution with distilled water, based on acidity constants of sulfuric acicl. Glycolic
acid (70 percent) was adjusted to pH 0, 1, 2, and 3 by addition of sulfuric acid and
distilled water based on the acidity constants of glycolic acid. The pH of each solution
T32
-------
was confirmed using both a titration of sodium hydroxide (NaOH) and an industrial pH
meter. For a given pH, 140 milliliter samples of 0, 10, 20, 40, and 60 grams per liter
iron were made by the addition of FeSO4 7H2O (iron sulfate, Fisher Scientific). Each
solution was placed in a 250 milliliter beaker and mechanically stirred at a rate of 80
revolutions per minute. A potential sweep at a rate of 20 millivolts per second was
applied to the solution using an EG&G Model 362 potentiostat. The cathode was
mad® of 20 mil stainless steel, 4 cm2 square. A piece of carbon was used as the
anode and a saturated calomel electrode (SCE) used as the reference electrode. The
current measured by the potentiostat for three consecutive cyclic potential sweeps was
recorded on an X-Y recorder. The current range, as limited by the potentiostat, was
set at the maximum of 1 A. All potentials were presented versus SCE (SCE potentials
equal normal hydrogen electrode - NHE - potentials plus 0.2415 volts). For each
solution measured, qualitative information about the deposits was recorded. Between
solutions, the stainless steel cathode was cleaned and polished with coarse emery
paper. In addition to the synthetic acid solutions, a current versus potential plot was
generated for a 140 milliliter sample of untreated primary rinse water. An analysis of
this rinsewater is shown in Table 1.
Table 1. Analysis of Electropolishing Primary Rinsewater (Total Metals)
-------
using a Perkin Elmer R100 Strip Recorder advancing at a rate of 5 minutes per hour.
The final series of experiments were conducted to determine the effect of pH on
the current at a constant applied potential. A constant voltage of 0.4 volts was applied
to primary rinsewater samples of 140 milliliters with 0, 10, 16, and 23 grams per liter
of NaOH added and the current over time recorded.
Both the sulfuric and glycolic acid solutions at pH 3 (pH's measured for these
solutions were 2.92 for the sulfuric and 2.88 for the glycolic) had a yellowish color and
formed precipitates, suggesting that the iron had been oxidized to the ferric form. The
presence of ferric iron is undesirable for plating, and therefore no tests were
performed on these solutions. However, it is possible to conclude thai: the optimal pH
for plating in these solutions is at a pH lower than 3.
In sulfuric and glycolic solutions with no iron added, the current generated by
hydrogen production was found to increase with decreasing pH. At a pH close to 0
(pH was measured at 0.13 for sulfuric and at -0.04 for glycolic), the production of
hydrogen was observed to be so rapid and violent at voltages above 0.6 volts that it is
not expected that good iron deposits will form and adhere to the cathode at these
voltages. This observation was expected from a comparison of the standard electrode
potentials for iron formation and hydrogen production:
Fe2* + 2e' -> Fe E° = -0.44 V (NHE)
2H+ + 2e' -> H2(g) E° = 0.00 V (NHE)
Comparing curves of sulfuric acid solutions with an iron concentration of 40
grams per liter at pH values of 0, 0.97, and 1.82 demonstrate that, at a pH of 0, the
hydrogen production is the dominant reaction. Therefore, it seems likely that the
optimal pH for plating in these acids will be at a pH higher than 0.
At all pH values, the carbon anode was observed to dissolve significantly in the
acid solutions, it is likely that in any working system using a carbon anode, the anode
would have to be separated from the working solution using a membrane or a salt
bridge.
When comparing current-voltage curves of sulfuric and glycolic acid with varying
iron concentrations at a pH near 1, increasing the iron concentration increases the
current passed. For the sulfuric acid solutions, an anodic current develops during the
return sweep, indicating dissolution of the plated material. This dissolution was also
visually observed in the sulfuric acid solutions. Except at a pH of 1.87 and iron
concentrations of 40 and 60 grams per liter, no anodic current was recorded for any of
the glycolic solutions. Iron deposits in the sulfuric acid solutions at pH 1 and 2 (actual
134
-------
pH measured 0.972 and 1.82) were significant and "hairy" at iron concentrations of 40
and 60 grams per liter. Little hydrogen production was observed. At iron
concentrations of 10 and 20 grams per liter, iron deposits in the sulfuric acid solution
were only noticeable as a slight discoloration on the cathode, with little hydrogen
production. Hydrogen gas bubbles formed at the cathode were not readily dislodged.
This agrees with published information on iron plating, which states that at least 40
grams per liter is required for an adequate current density. For all sulfuric acid
solutions, observation of the cathode after removal from the test solution showed that
iron powder was retained at the cathode. No iron plating was visually observed in any
of the glycolic acid solutions. It is likely that the iron forms a complex in this acid.
The approximate pH of the rinsewater from Pier-Sol was measured at -0.39.
Estimates of the pH of this rinsewater after known additions of sodium hydroxide
indicate that about 150 grams per liter of sodium hydroxide are needed to raise the pH
of this solution to 1, and about 200 grams per liter of sodium hydroxide are needed to
raise the pH of this solution to 2. The current passed in the sweep out to 1.5 volts
decreases with increasing NaOH additions. This is to be expected, because additions
of NaOH raises the pH indicating a decrease in hydrogen production. This trend was
also noticed in the synthesized solutions when the pH was raised. However, on the
return sweep, the anodic current that may indicate the dissolution of a plate increased
slightly as the NaOH concentration is increased in solution.
The rinsewater solution is very dark (opaque) making visual observation of the
reaction at the cathode impossible. After current/voltage sweeps, the cathode retained
a black slime approximately 1 millimeter thick. Initial cathode weights were taken
before each current-voltage sweep. The "plate" was allowed to air dry until no excess
water was observed (10-20 minutes). The cathode was reweighed for a gross
approximation of the amount of loose plate collected. The cathode was then rinsed
with distilled water. In all cased the primary adherent layer was uniformly copper as
evidenced by a shiny copper color. The plate was again allowed to air dry until no
excess water was observed and the weight of the cathode with the adhered plate
remeasured. Table 2 lists the approximate pH, the gram per liter weight of NaOH
addition, the weight of the loose plate, and the weight of adhered plate.
The oven weights indicate that approximately 50 milligrams of metals could be
plated during the roughly 4 minutes that it takes to run 3 sweeps.
(Comparison of the current-voltage sweep for the untreated rinsewater with
sulfuric and glycolic acid solutions at pH 0 and at iron concentrations of 40 and 60
grams per liter indicate that the untreated rinsewater plated more than each
synthesized solution, since the anodic current is greater. This result is expected since
the untreated rinsewater contains other metals, such as copper, nickel, and chromium,
which are also expected to be plated. While the concentration of iron in the untreat€>d
rinsewater may be 40 to 60 grams per liter, the total metals concentration is expected
135
-------
to be significantly higher.
Table 2. Loose and Adhered Plate Weights
« ~ \ - j*v>\ ^v£^w*
-------
during the plating process; this is seen only at 0.2 and 0.3 volts. At 0.4 and 0.5 volts
there may be a transition where the hydrogen product-ion reaction begins to
significantly compete at the cathode.
Measurements of cathode weight accumulated over the one hour run of each of
these tests indicate that approximately 100 milligrams of plate/slime can be recovered
from solution. Testing to determine how much metal could be removed from solution
using an 8 centimeter* electrode at an applied voltage of 0.4 volts (SCE) showed that
after 12 hours of plating and scraping, metals were still being removed from solution.
Metal concentrations before and after the base addition were within 2 to 20 percent,
indicating that the base addition did not affect metal concentrations. After the
electrolytic treatment, the concentrations of chromium, iron, and nickel were again
within 'this range of accuracy. The copper concentration decreased by about 75
percent. These results support analysis that copper is the primary metal removed
from the rinsewater.
While the literature and the results from the synthesized solutions suggest thatt
an optimal pH range for iron plating is between 1 and 2, and iron concentrations
above 40 grams per liter, the conditions of the actual solution show that optimal metal
plating from the primary rinsewater can be achieved with as little as 10 grams per liter
(a pH of less than 0) to as much as 16 grams per liter (a pH of approximately .37).
This is best explained by the results of an EDAX elemental analysis which show that
although the concentration of copper, chromium, and nickel are much lower than iron,
they are all plated together and in proportion to their standard electrode potentials.
Thus, the predominant metal plated is copper. Approximately 50 milligrams of a slimy
plate could be recovered from the solution in a 4 minute potential sweep, while 100
milligrams were recovered after 1 hour when a constant voltage was applied. The
optimal voltage for plating metals from primary rinsewater was found to be 0.4-0.5
volts.
Although it would seem that significant metals can be removed from the primary
rinsewater through electrodeposition, this study was unable to determine the exact
nature of the deposits formed. The slime retrieved from the cathode did not easily dry
and instead formed a sludge. It was not determined if the metals detected by EDAX
are in their elemental states or in some hydroxide or other, complexed state. Only ilf
the metals are in their elemental state could the plate be considered non-hazardous
and be easily managed. Further analyses of the sludge are required to determine the
stability and nature of the deposits formed.
Because the results of Phase II testing indicated that electrolytic recovery may
not be an appropriate management alternative, Phase III of this project investigated
waste minimization via process control.
The primary parts electropolished by Pier-Sol are mouse cage lids for medical
137
-------
research supply companies. Estimates of metal removal from those parts by
electropolishing were done by measuring stainless steel thickness and by weighing the
part before and after electropolishing. Results from both methods are in close
agreement and suggest that approximately 34 kilograms of steel are removed from the
parts and added to the polishing tank system every normal work week. Details of
these calculations are presented in Table 3.
Table 3. Calculation of Metal Removal During Electropolishing
Part Mass
Before Electropolishing
367.0 grams
After Electropolishing
357.4 grams
Difference
9.6 grams
Part Volume*
Before Electropolishing
2.595 in3
After Electropolishing
2.517 in3
Difference
0.078 in3
Conversion from in8 to cm3
x 16.39 cm3/in3 • 12.78 cm3
Typical Steel Density
x 7.85 g/crn3
Total Mass of Steel Removed
Average of 2 Values
10.0 grams
9.8 grams steel/week
Estimated Throughput
3,500 parts/week (16 hrs/day,
5 days/week)
Total Metal Removal
34 kg steel/week
x 50 weeks/year
1,700 kg steel/year
* Determined using micrometer
Consequently, the metal removal process to be designed should be capable of
handling the same metal mass. The iron released for any product throughput can be
calculated by changing the appropriate part throughput value in the above Table and
continuing the calculation.
138
-------
It was also found that the amount of stainless steel removed by a typical
electropolishing treatment strongly depends on the age of the polishing bath. In an
examination of metal removal rates, it was determined that mouse cage lids polished
using an old bath ready for desludging (sludge removal with subsequent addition of
fresh acids) removed as little as 0.3 percent of the total cage weight during
electropolishing with little variations among lids. In contrast, electropolishing the same
lids using a fresh bath removed an average of 4 percent of the stainless steel from the
cages with a variation of 2 to 6 percent. All of the cages were polished to acceptable
quality. The electropolishing time is approximately 10 minutes, regardless of bath age.
Mouse cage lids have been collected and monitored over a 4 month period
encompassing portions of 4 electropolishing bath cycles. The cages were weighed
and the metal removal calculated based on the average difference in mass between
the polished and unpolished cages. Table 4 shows the results from this investigation
during which two types of cages were processed.
Table 4. Weights of Electropolished Cage Lids at Various Bath Ages
Un|X)lished Cages
409.1
408.7-409.5
approx. 9
408.0
407.2-408.8
B
approx. 1/2
391.8
384.2-399.4
1.9
393.6
386.6-400.6
4.6
399.7
396.6-402.8
5.7
397.4
395.1-399.7
1.6
395.0
392.7-397.4
9.1
404.6
403.8-405.4
Unpolished Cages
619.5
614.9-624.1
3.3
604.0
601.8-606.2
On average, 17 grams of stainless steel from the cages were removed in new
baths, while this value approached 1 gram in spent baths.
139
-------
RESULTS AND DISCUSSION
PERFORMANCE RESULTS
Electrodeposition of iron for iron recovery was not successful. Although it
would seem that significant metals can be removed electrolytically, the adhered plate
is a slime that dries to a sludge suggesting that the metals may not be present in their
elemental non-hazardous form. An elemental analysis of the plated material showed
that much of the plate is copper and other metals rather than iron. Further analyses
of the sludge are needed to determine the forms of the metals deposited.
Controlling electropolishing time based on the "freshness", or current metal
content, of the electropolishing tank (a solution low in metal content polished a piece
more quickly) has great promise in waste minimization. The current electropolishing
time is about 10 minutes; thus if polishing time is decreased during the initial weeks of
the bath, the metal removal will be less, and the bath life extended. A minimum
electropolishing time may be used in fresh baths, and the time can be extended up to
the full 10 minutes as the bath ages.
Tabulation of Data
The rate of metal removal in a fresh bath is approximately 1.9 grams per
minute for the small cages. A removal target of, for example, 4 grams would reduce
the initial electropolishing time to about 2.1 minutes. Consequently, during this initial
week, the metal input to the bath would decrease from about 17 grams per cage to 4
grams per cage. At 3,500 cages per week (estimated), this corresponds to a
reduction from 131 to 31 pounds of stainless steel added to the polishing bath, with
similar reductions in sludge production during the first week of a fresh bath. Less
significant reductions would result in subsequent weeks of the bath life. Such a
process control system based on metal removal is more efficient than one based on
electropolishing time; however, this control is more difficult. A precision balance may
be used to monitor removed stainless steel from the lids.
Cost/Benefit Analysis
An in-depth economic analysis for the electrodeposition process was not
performed, as it was determined from the experimental work that it would be too costly
or personnel intensive for a small facility such as Pier-Sol. Electrodeposition may be
feasible on a large scale. However, the question of the stability of the plated material
must be addressed. If the plated sludge-like material is hazardous, no advantage
would be realized from the electrodeposition process. In addition, while iron is readily
precipitated as FePO4 with H3PO4, the pH needed to plate iron requires a significant
140
-------
volume increase with caustic solution.
The two most recent desludgings at Pier-Sol have each taken place after 91/2
weeks of electropolishing. The desludgings produced 4 and 5 drums of sludge
respectively. Current disposal costs $370 plus $50 transportation per drum. Thus at
5.5 desludgings per year (52/9.5), 41/2 drums per desludge, and $420 per drum,
Pier-Sol is paying $10,400 per year in sludge disposal costs from this electropolishing
line.
The average amount of stainless steel removed during a bath life is estimated
to b© 9 grams per lid. Thus:
(9 grams/lid)x(3,500 lids/week)x(9.5 weeks/bath) = 300,000 grams steel/bath
This number predicts 1,650 kilograms of steel removed per year.
If, via process control procedures, all lids were equally polished to a 4 grams
per lid removal, a bath would polish 75,000 lids and, consequently last 21 weeks at
the same throughput - more than double the current bath life. The desludging would
be required only 2.5 times a year (which in itself saves time and labor), resulting in a
yearly waste disposal cost of $4,680 - less than half the current cost. This estimate
assumes that electropolishing throughput remains constant.
The value of 4 grams per lid was chosen arbitrarily, assuming that acceptable
electropolishing can be accomplished with this 4 gram metal removal. The exact
amount of metal removed, electropolishing efficiency, and process controls will be
further examined.
CONCLUSIONS
POLLUTION PREVENTION ASSESSMENT
Incentives
Process changes - such as Pier-Sol's alteration of electropolishing time based
on the "freshness of the bath - are very economical to integrate into an operation.
Equipment investments are often minimal. Pier-Sol also found that labor and
maintenance time decreased, and disposal costs for hazardous materials dropped.
Determining the minimum metal removal for maximum product quality, and fine tuning
processing time to the age of the bath will enhance the economics of this process
change.
141
-------
Barriers
The electrodeposition and reclamation of iron was not successful for this
operation. The variety of metals which were plated in the sludge-like material must be
further analyzed to determine the nature of these metals.
Through the literature and analysis of working conditions at Pier-Sol, other
methods may be explored for controlling or reducing metal accumulation in the
electropolishing tank. Several methods of note are: investigating the patent for
microporous media that selectively removes iron, and directly pumping sludge from the
bottom of the tank to a drying bed to reduce operational downtime.
142
U-S- GOVERNMENT PRINTING OFFICE: 1993 - 750-002/80<>76
-------
-------
-------
-------
rn
I
o
o
•£
SP
§11
=
~ CD
< CO
a> co
03
o o
ii
* 3
00 CD
5T
-a
I
o^
5'
J3 >
CD CQ
£ §
§-5
CO
£ &=
------- |