United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-92/052 October 1992
ENVIRONMENTAL
RESEARCH BRIEF
Waste Reduction Activities and Options for a Manufacturer of
Fire Retardant Plastic Pellets and Hot Melt Adhesives
Hanna Saqa and Daniel J. Watts*
Abstract
The U.S. Environmental Protection Agency (EPA) funded a
project with the New Jersey Department of Environmental
Protection and Energy (NJDEPE) to assist in conducting waste
minimization assessments at 30 small- to medium-sized busi-
nesses in the state of New Jersey. One of the sites selected
was a facility that manufactures fire retardant plastic pellets
and hot melt adhesives. The manufacturing process for the
plastic pellets uses a batch procedure in mixers where resins
are combined with flame retardants and other additives. The
mix is albwed to solidify and formed into pellets. The hot melt
adhesive is produced by extruding a polymer with the necessary
additives followed by washing and palletizing. A site visit was
made in 1990 during which several opportunities for waste
minimization were identified. Options identified included changes
in sequencing of production, modifications of wastewater treat-
ment practices, changes in hydraulic oil use and reuse practices.
Implementation of the identified waste minimization opportuni-
ties was not part of the program. Percent waste reduction, net
annual savings, implementation costs and payback periods
were estimated.
This Research Brief was developed by the Principal Investiga-
tors and EPA's Risk Reduction Engineering Laboratory in Cin-
cinnati, OH, to announce key findings of this completed as-
sessment.
Introduction
The environmental issues facing industry today have expanded
considerably beyond traditional concerns. Wastewater, air
emissions, potential soil and groundwater contamination, solid
waste disposal, and employee health and safety have become
increasingly important concerns. The management and dis-
posal of hazardous substances, including both process-related
wastes and residues from waste treatment, receive significant
attention because of regulation and economics.
As environmental issues have become more complex, the
strategies for waste management and control have become
more systematic and integrated. The positive role of waste
minimization and pollution preventbn within industrial operations
at each stage of product life is recognized throughout the
world. An ideal goal is to manufacture products while generat-
ing the least amount of waste possible.
The Hazardous Waste Advisement Program (HWAP) of the
Division of Hazardous Waste Management, NJDEPE, is pursu-
ing the goals of waste minimization awareness and program
implementation in the state. HWAP, with the help of an EPA
grant from the Risk Reduction Engineering Laboratory, con-
ducted an Assessment of Reduction and Recycling Opportuni-
ties for Hazardous Waste (ARROW) project. ARROW was
designed to assess waste minimization potential across a
broad range of New Jersey industries. The project targeted 30
sites to perform waste minimization assessments following the
approach outlined in EPA's Waste Minimization Opportunity
Assessment Manual (EPA/625/7-88/003). Under contract to
NJDEPE, the Hazardous Substance Management Research
Center at the New Jersey Institute of Technology (NJIT) as-
sisted in conducting the assessments. This research brief
presents an assessment of the manufacturing of fire retardant
plastic pellets and hot melt adhesives (1 of the 30 assess-
ments performed) and provides recommendations for waste
minimization options resulting from the assessment.
* New Jersey Institute of Technology, Newark, NJ 07102
Printed on Recycled Paper
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Methodology of Assessments
The assessment process was coordinated by a team of techni-
cal staff from NJIT with experience in process operations,
basic chemistry, and environmental concerns and needs. Be-
cause the EPA waste minimization manual is designed to be
primarily applied by the in-house staff of the facility, the degree
of involvement of the NJIT team varied according to the ease
with which the facility staff could apply the manual. In some
cases, NJITs role was to provide advice. In others, NJIT
conducted essentially the entire evaluation.
The goal of the project was to encourage participation in the
assessment process by management and staff at the facility.
To do this, the participants were encouraged to proceed through
the organizational steps outlined in the manual. These steps
can be summarized as follows:
• Obtaining corporate commitment to a waste minimization
initiative
• Organizing a task force or similar group to carry out the
assessment
• Developing £ policy statement regarding waste minimiza-
tion for issuance by corporate management
• Establishing tentative waste reduction goals to be achieved
by the program
• Identifying waste-generating sites and processes
• Conducting a detailed site inspection
• Developing a list of options which may lead to the waste
reduction goal
• Formally analyzing the feasibility of the various options
• Measuring the effectiveness of the options and continuing
the assessment.
Not every facility was able to follow these steps as presented.
In each case, however, the identification of waste-generating
sites and processes, detailed site inspections, and development
of options was carried out. Frequently, it was necessary for a
high degree of involvement by NJIT to accomplish these steps.
Two common reasons for needing outside participation were a
shortage of technical staff within the company and a need to
develop an agenda for technical action before corporate com-
mitment and policy statements could be obtained.
It was not a goal of the ARROW project to participate in the
feasibility analysis or implementation steps. However, NJIT
offered to provide advice for feasibility analysis if requested.
In each case, the NJIT team made several site visits to the
facility. Initially, visits were made to explain the EPA manual
and to encourage the facility through the organizational stages.
If delays and complications developed, the team offered assis-
tance in the technical review, inspections, and option develop-
ment.
No sampling or laboratory analysis was undertaken as part of
these assessments.
Facility Background
The facility is a manufacturer of plastic pellets with fire retardant
properties. The pellets are typically used for wire and cable
coating and insulation. The facility also manufactures hot melt
adhesives used primarily for metal-metal bonding.
The facility is located in a rural area and employs about 120
people. In addition to the equipment used directly for production,
there are tanks used for wastewater treatment and a pond
where non-hazardous water is piped.
Manufacturing Processes
The production of the plastic formulation for the wire insulation
pellets takes place in a Banbury mixer. Powdered polyethylene
resins and various combinations of additives including bromi-
nated fire retardants, fillers, and colorants such as antimony
oxide and carbon black are metered in and mixed. The
resulting composition is spread onto a conveyor for hardening
and then mechanically chopped into pellets.
The hot melt adhesive process requires combining and melting
polypropylene, acrylic acid, and an organic peroxide in an
extruder. The specific organic peroxide used changes depend-
ing upon the desired performance characteristics of the final
product. The mixed melt is extruded onto a ventilated con-
veyor and transported to a slurry washing station. The washed
product is palletized and dried before packaging as the finished
product.
Existing Waste Management Activities
The company has already instituted some environmental prac-
tices designed to encourage reuse of materials and to minimize
worker risk. Their willingness to participate in this study indicates
the interest of the management of the facility in strengthening
their pollution prevention activities. The two major product
lines are substantially different in their manufacturing steps; the
waste management practices and requirements for the two
therefore differ.
The plastic pellet process utilizes a low hazard material and is
essentially a mixing process with little or no potential for emis-
sions. There is a potential for dust emission during the mixing
step. This is addressed using hydraulic oil dust seals at each
end of the mixer rotor. This oil, contaminated with mixture
ingredients, drips into 5-gal containers. When these containers
are.filled the accumulated oil is emptied into a 55-gal drum
where the heavier materials settle to form a sludge. Periodically,
the oil is pumped out for recycling and the sludge is mixed with
clay and landfilled. Approximately 3200 gal of waste oil and
200 drums of sludge are generated each year. In addition,
water from housekeeping operations and from cleaning the
mixers is collected in sumps and pumped to tanks to allow
skimming of oil for recycling. The oil-free water, about 50,000
gal/day is pumped to the pond onsite.
The hot melt adhesive production process involves a scrubbing
process for the captured air emissions produced after the
extrusion step. The exhaust from a hood is passed through a
water scrubber. The contaminant which is acrylic acid is
retained by the water. After about one week in the scrubber,
the water is pH adjusted and sent to a storage tank. Water
used in product washing is similarly treated and sent to the
storage tank about once a week. The accumulated wastewater
(about 7,000 gal/wk) is sent offsite for disposal at a cost of
about $0.42/gal. The level of acrylic acid is about 1%. This
process also produces waste peroxide. When product types
are changed, the practice at the facility is to purge the peroxide
metering apparatus with the peroxide material to be used in the
next batch. The collected purge material is then a mixture of
organic peroxides. The quantity of this material varies depending
upon production rates, but about 1-2 quarts is produced with
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each purge. The mixture is accumulated in drums at the site.
Presently, the facility is seeking an effective disposal practice
for this mixture of wastes. The manufacturer recommends
disposal by incineration, after mixing with oil to a level of
peroxide no greater than 5% of the mixture.
The appearance of the facility shows that the management and
employees recognize the waste reduction value of careful
movement of raw materials, good maintenance of equipment,
and spill control and spill prevention activities.
Waste Minimization Opportunities
The type of waste currently generated by the facility, the
source of the waste, the quantity of the waste and the annual
treatment and disposal costs are given in Table 1.
Table 2 shows the opportunities for waste minimization recom-
mended for the facility. The type of waste, the minimization
opportunity, the possible waste reduction and associated sav-
ings, and the implementation cost along with the payback time
are given in the table. The quantities of waste currently
generated at the facility and possible waste reduction depend
on the level of activity of the facility.
ft should be noted that the economic savings of the minimiza-
tion opportunity, in most cases, results from the need for less
raw material and from reduced present and future costs asso-
ciated with waste treatment and disposal. It should also be
noted that the savings given for each opportunity reflect the
savings achievable when implementing each waste minimization
' Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
opportunity independently and do not reflect duplication of
savings that would result when the opportunities are imple-
mented in a package. Also, no equipment depreciation is
factored into the calculations.
Regulatory Implications
There are potential regulatory implications of pollution preven-
tion initiatives at this facility. Any changes in the scrubbing
system may be impacted by the requirements of the air permit.
If any permit conditions need to be changed then implementa-
tion of pollution prevention concepts may be delayed. The
pond at the facility which currently receives non-hazardous
aqueous streams may be impacted by changing water discharge
regulations. In that case additional operational changes may
be required to address new regulations. The accumulation of
mixed organic peroxides at the facility must be done in accor-
dance with RCRA and state regulations. Overall, a facility
such as this should encourage implementation of additional
pollution prevention practices.
This Research Brief summarizes a part of the work done under
cooperative Agreement No. CR-815165 by the New Jersey
Institute of Technology under the sponsorship of the New
Jersey Department of Environmental Protection and Energy
and the U.S. Environmental Protection Agency. The EPA Project
Officer was Mary Ann Curran. She can be reached at:
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
Table 1. Summary of Current Waste Generation
Waste Generated
Source of Waste
Annual Quantity
Generated
Annual Waste
Management Costs
Waste Hydraulic Oil
Oil Sludges
Oil dust seals on Banbury
mixers
Process residues captured by
oil in the mixer
Acrylic Acid Contaminated Air scrubber from adhesive hood
Water and washing of product
Mixed Peroxides Material used to purge raw material
metering system
3200 gal
200 drums
364,000 gal
20 drums
(estimated)
$1,600
40,000
153,000
120,000
(based on estimated
incineration costs
as recommended by
manufacturer)
&U.8. GOVERNMENT PRINTING OFFICE: 1994 - SSfr«i7/MllS
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Table 2. Summary of Recommended Waste Minimization Opportunities
Waste Stream
Reduced
Minimization Opportunity
Annual Waste Reduction
Quantity Percent
Net Implementation Payback
Annual Savings Cost Years *
Waste OH Filtration or centrifugation 1600 gal
of oil allowing reuse
Wastewater Evaluate scrubber water 109,000 gal
Containing and wash water to determine
Acrylic Add which has the tower level of
acrylic acid. Use the one
with the lower level as the
makeup for the other. This will
reduce the total volume of water
used.
Removal of acrylic acid from 328,000 gal
water by ion exchange or reverse
osmosis allowing water reuse and
producing another type of waste stream
with higher levels of acrylic add.
Mixed Organic Use air purge capability 18 drums
Peroxides designed into equipment.
Keep separate the air-purged
peroxides and use them in the
next batch. Some washing with
solvent such as hexane of critical
mechanical parts may be desired,
generating a much smaller waste
stream.
50 $3,200 $10,000
30 45,800
200 immed.
90 67,000
90 110,000
75,000
1.1
100 immed.
* Savings result from reduced raw material and treatment and disposal costs when implementing each minimization opportunity independently.
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
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EPA/600/S-92/052
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