United States
National Risk Management
Environmental Protection
Agency
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/009 August 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a Manufacturer of
Paints and Coatings
Marvin Fleischman*, Patrick A. Schmidt*,
and Gwen P. Looby**
Abstract
The U.S. Environmental Protection Agency (EPA) has funded
a pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the expertise to do so. Waste Minimization Assessment Cen-
ters (WMACs) were established at selected universities and
procedures were adapted from the EPA Waste Minimization
Opportunity Assessment Manual (EPM625/7-88/003, July 1988).
That document has been superseded by the Facility Pollution
Prevention Guide (EPA/600/R-92/088, May 1992). The WMAC
team at the University of Louisville performed an assessment
at a plant that manufactures paints and coatings. Raw materi-
als are received and staged appropriately for batches of prod-
uct. Processing in this plant includes mixing of raw materials,
filtering, pumping and milling. Additional materials may be
added in letdown tanks prior to product filling, packaging, and
shipping. The team's findings and recommendations indicated
that the plant generated waste wash water and solvent from
equipment cleaning in large quantities and that significant waste
reduction and cost savings could be achieved by removing
more of the product from the letdown tanks prior to cleaning
them.
This Research Brief was developed by the principal investiga-
tors and EPA's National Risk Management Research Labora-
tory, Cincinnati, OH, to announce key findings of an ongoing
research project that is fully documented in a separate report
of the same title available from University City Science Center.
Introduction
The amount of waste generated by industrial plants has be-
come an increasingly costly problem for manufacturers and an
"University of Louisville, Department of Chemical Engineering.
"University City Science Center, Philadelphia, PA.
additional stress on the environment. One solution to the
problem of waste generation is to reduce or eliminate the
waste at its source.
University City Science Center (Philadelphia, PA) has begun a
pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the in-house expertise to do so. Under agreement with EPA's
National Risk Management Research Laboratory, the Science
Center has established three WMACs. This assessment was
done by engineering faculty and students at the University of
Louisville's WMAC. The assessment teams have considerable
direct experience with process operations in manufacturing
plants and the knowledge and skills needed to minimize waste
generation.
The pollution prevention opportunity assessments are done for
small and medium-size manufacturers at no out-of-pocket cost
to the client. To qualify for the assessment, each client must
fall within Standard Industrial Classification Code 20-39, have
gross annual sales not exceeding $75 million, employ no more
than 500 persons, and lack in-house expertise in pollution
prevention.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers and re-
duction of waste treatment and disposal costs for participating
plants. In addition, the project provides valuable experience for
graduate and undergraduate students who participate in the
program, and a cleaner environment without more regulations
and higher costs for manufacturers.
Methodology of Assessments
The pollution prevention opportunity assessments require sev-
eral site visits to each client served. In general, the WMACs
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follow the procedures outlined in the EPA Waste Minimization
Opportunity Assessment Manual (EPM625/7-88/003, July 1988).
The WMAC staff locate the sources of waste in the plant and
identify the current disposal or treatment methods and their
associated costs. They then identify and analyze a variety of
ways to reduce or eliminate the waste. Specific measures to
achieve that goal are recommended and the essential support-
ing technological and economic information is developed. Fi-
nally, a confidential report that details the WMAC's findings
and recommendations (including cost savings, implementation
costs, and payback times) is prepared for each client.
Plant Background
The plant manufactures oil- and water-based interior and exte-
rior architectural coatings, coatings for metal surfaces, and
other specialty coatings. It operates 4,125 hr/yr to produce
over 6 million gal/yr of product.
Manufacturing Process
Bulk liquids, including solvents, liquid resins, glycols, and pow-
ders, including pigment, are received and stored. As customer
orders are received and scheduled for production, the required
raw materials are collected according to a specific batch recipe
and staged.
Appropriate raw materials are mixed in the tank. The proper
particle size distribution in the final product is achieved using
either specially equipped dispersion tanks or mixing tanks in
conjunction with a milling process afterward. Once the proper
particle size is obtained in the batch, it is fed to a letdown tank
directly or indirectly through a filter, a pump, a mill, or any
combination of these pieces of equipment.
Once a batch from a dispersion tank is transferred to a letdown
tank, additional solvent and rheological additives are added in
order to adjust the batch's viscosity. Additives for other desir-
able product properties are also added in the letdown tank.
After the batch is approved by the quality control department, it
is sent to a filling machine.
Large batches are packaged automatically and small batches
are packaged semi-automatically or manually.
Lower quality paint is manufactured using waste products such
as quality control samples and customer returns. This paint is
used when color matches are not critical or when the presence
of metal-containing compounds does not pose a significant
hazard.
An abbreviated process flow diagram for this plant is shown in
Figure 1.
Existing Waste Management Practices
This plant already has taken the following steps to manage and
minimize its wastes:
• Most metal drums are returned to the supplier, sent to be
reconditioned, or used for hazardous waste disposal.
• Pallets from raw material shipments are reused, returned to
the supplier, or given away.
• Bulk liquid storage tanks are equipped with conservation
vents.
• Process equipment is dedicated to either oil-based or water-
based production in order to minimize cleaning waste.
• Long runs and light-to-dark runs are scheduled sequentially
to minimize cleaning waste.
• Mercury-containing paint has been phased out of production.
• Caustic and alkaline cleaners are not used by the facility.
• Pigment dust from three of the baghouses is returned to the
appropriate batch.
• Buckets are reused as long as possible in the prebatching
area.
• Equipment is cleaned immediately after a batch is finished in
order to reduce the amount of water or solvent required.
Some of the wash solvent and water is incorporated into the
batch being made.
• Foam plugs or "pigs" are used for cleaning some of the lines
and recovering product.
• Cardboard layers separating the cans used for the product
packaging are used as spill absorbents, reducing the quan-
tity of absorbents purchased. A portion of the separators is
returned to the supplier for reuse.
• Oil-based and water-based wastes are segregated.
• Reusable wire strainers are used for filtration instead of
cartridge filters.
• Several potential waste streams are reused in formulating
lower-quality paint.
• Damaged dry metal product cans are recycled offsite.
• Waste cardboard and office paper are recycled offsite.
• Styrofoam "popcorn" received with shipments is reused in
outgoing shipments.
Pollution Prevention Opportunities
The type of waste currently generated by the plant, the source
of the waste, the waste management method, the quantity of
the waste, and the annual waste management cost for each
waste stream identified are given in Table 1.
Table 2 shows the opportunities for pollution prevention that
the WMAC team recommended for the plant. The opportunity,
the type of waste, the possible waste reduction and associated
savings, and the implementation cost along with the payback
time are given in the table. The quantities of waste currently
generated by the plant and possible waste reduction depend
on the production level of the plant. All values should be
considered in that context.
It should be noted that the economic savings of the opportu-
nity, in most cases, result from reductions in raw materials and
waste treatment and disposal costs. Other savings not quantifi-
able by this study include a wide variety of possible future
costs related to changing emissions standards, liability, and
employee health. It also should be noted that the savings given
are for each pollution prevention opportunity independently and
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Products shipped to customers
Figure 1. Abbreviated process flow diagram for paint formulation.
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Table 1. Summary of Current Waste Generation
Waste Generated Source of Waste
Pigment bags and residual powder
Fiber drums, paper bags, and buckets
Metal drums
Solvent drum heels
(lost with drums shipped offsite)
Dispersed pigment dust
Evaporated solvent
Packaging/shipping wastes
(shrink wrap and binding straps)
Pallets
Cardboard
Raw material samples
Raw material sample cans
Drip bucket liquid
Drip buckets
Wash water/paint solids
Supernatant from metal-containing
wash water
Sludge from metal-containing
wash water
Spent wash solvent/paint solids
Solvent-based filter/strainer solids
Water-based filter/strainer solids
Clean-up waste (rags, floor
sweepings, pigment dust)
Damaged metal containers
Damaged plastic containers
Damaged cardboard boxes
Damaged packaging material
Miscellaneous wastewater
Raw materials handling
Raw materials handling
Raw material handling
Raw material handling
Raw material handling
Raw material handling
Received with raw materials
Received with raw materials
Received with raw materials
Quality control sampling
Quality control sampling
Leaks from product formulation
Used to contain leaks
Equipment cleaning for
water-based paint
Equipment cleaning for metal-
containing water-based paint
Equipment cleaning for metal-
containing water-based paint
Equipment cleaning for
oil-based paints
Filtering during solvent-based
paint production
Filtering during water-based
paint production
Clean-up
Product handling
Product handling
Product packaging
Product packaging
Various sources
Waste Management
Method
Compacted; shipped
offsite to landfill
Shipped offsite to landfill
Shipped offsite for reconditioning
Shipped offsite
Collected in baghouses;
shipped offsite to landfill
Evaporated to plant air and
atmosphere
Shipped offsite to landfill
Reused onsite, returned to
supplier, or given away
Shipped offsite for recycling
Blended into maintenance paint
Shipped offsite to landfill
Blended into maintenance paint
Shipped offsite to landfill
Sewered
Decanted from sludge; sewered
Blended into fence paint
Shipped offsite to be
used as fuel
Shipped offsite as hazardous
waste; landfilled or burned
Shipped offsite to landfill
Shipped offsite to landfill
Shipped offsite to landfill
or for recycling
Shipped offsite to landfill
Shipped offsite for recycling
Shipped offsite to landfill
Sewered
Annual Quantity
Generated (Ib/yr)
507,000
5,100
683,000
272,000
750
2,000
55,000
1,400,000
n/a
14,400
1,600
2,500
100
11,300,000
280,000
271,800
967,000
12,000
37,200
16,300
513,000
184,000
77,000
40,400
20,800,000
Annual Waste
Management Cost
$225,000
3,810
125,000
42,600
770
300
1,160
-
n/a
30
negligible
358,320
8,680
-
2,877,000
20,300
780
340
353,820
143,880
850
5,140
'Includes waste treatment, disposal, and handling costs, and applicable lost raw material value.
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do not reflect duplication of savings that would result when the
opportunities are implemented in a package.
Additional Recommendations
In addition to the opportunities analyzed by the WMAC team,
several additional measures were considered. These mea-
sures were not completely analyzed because of insufficient
data, minimal savings, implementation difficulty, or a projected
lengthy payback. Since one or more of these approaches to
pollution prevention may, however, increase in attractiveness
with changing conditions in the plant, they were brought to the
plant's attention for future consideration.
The measures considered include the following:
• Obtain raw materials in dissolvable bags to reduce packag-
ing wastes.
• Use pastes orslurries instead of powdered pigmentto reduce
the quantity of waste paper bags generated.
• Purchase raw materials in reusable containers.
• Reuse "empty" powder bags in prebatching instead of ship-
ping them to landfill.
• Find an appropriate method of recycling empty paper bags.
• Reduce pigment dust losses by installing deflector curtains
on the tank lids attached to the mixers.
• Use currently discarded pigment dust in fence paint when
possible.
• Recover solvent losses by using chillers, adsorbers, or
compressors on the bulk storage tank vents.
• Install and use lids on process tanks to prevent evaporative
losses.
• Replace splash filling of tanks with submerged filling.
• Install high-pressure low-volume nozzlesto reduce the amount
of cleaning water used.
• Use hydrocyclone to remove suspended solids from wash
water thereby reducing water quality surcharges.
• Use countercurrent solvent rinsing of tanks for cleaning.
• Investigate the possibility of sending damaged labels back to
the supplier for recycling.
This research brief summarizes a part of the work done under
Cooperative Agreement No. CR-814093 by the University City
Science Center under the sponsorship of the U.S. Environmen-
tal Protection Agency. The EPA Project Officer was Emma
Lou George.
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United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use
$300
EPA/600/S-95/009
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