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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. In an effort to assist these manufacturers Waste Minimization Assessment Centers (WMACs) were

established at selected universities, and procedures were

adapted from the EPA Waste Minimization Opportunity Assessment Manual (EPA/625/7-88/003, July 1988). That document has been superseded by the Facility Pollution Prevention

Guide (EPA/600/R-92/088, May 1992). The WMAC at the University of Tennessee performed an assessment for a plant that

manufactures lacquers and paints. Raw materials, including

additives and solvent or water, are blended at mixing stations.

The resulting mixture may be ground in a sand-mill or a

pebble-mill. Next, the mixture is pumped to the let-down tanks

where additives, tints, resins, and solvent or water are added.

After testing and any required adjustments, the product is

packaged. The team’s report, detailing findings and recommendations, indicated that waste solvent is the waste stream

generated in the greatest quantity and that significant cost

savings could be achieved by implementing a computer-based

system for batch scheduling, inventory, and waste documentation.

This Research Brief was developed by the principal investigators and EPA’s Risk Reduction Engineering Laboratory, 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 become an increasingly costly problem for manufacturers and an

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

Risk Reduction Engineering Laboratory, the Science Center

has established three WMACs. This assessment was done by

engineering faculty and students at the University of

Tennessee’s (Knoxville) WMAC. The assessment teams have

considerable direct experience with process operations in manufacturing plants and also have the knowledge and skills needed

to minimize waste generation.

The waste minimization 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 waste minimization.

The potential benefits of the pilot project include minimization

of the amount of waste generated by manufacturers and reduced 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.

Waste Minimization Assessment for a Manufacturer

of Paints and Lacquers

United States

Environmental Protection

Agency

Risk Reduction

Engineering Laboratory

Cincinnati, OH 45268

ENVIRONMENTAL

RESEARCH BRIEF

Research and Development EPA/600/S-94/007 September 1994

Richard J. Jendrucko*, Rebecca A. Bachschmidt*,

and Gwen P. Looby**

* University of Tennessee, Department of Engineering Science and Mechanics. ** University City Science Center, Philadelphia, PA.

E AP
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Methodology of Assessments

The waste minimization assessments require several site visits

to each client served. In general, the WMACs follow the procedures outlined in the EPA Waste Minimization Opportunity

Assessment Manual (EPA/625/7-88/003, 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 supporting technological and economic information is developed. Finally, 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

This plant manufactures lacquers and consumer and industrial

water-based and solvent-based paints. It operates 4,000 hr/yr

to produce approximately 1.5 million gal of paint and lacquer

annually.

Manufacturing Process

The raw materials used by this plant include pigments, resins,

fillers, plasticizers, dryers, preservatives (for water-based paints),

solvents, and water. Water-based paints represent about onethird of the total production; the remainder is solvent-based.

The production processes for water-based and solvent-based

products are very similar; the major distinction between the

processes is the use of water or solvent.

Specified amounts of raw materials are prepared for batches of

product in the pre-batch area. Those ingredients, other additives, and solvent or water are blended at one of several

mixing stations. Pigment dispersion is checked and if it is

unacceptable the mixture is ground in a sand-mill or a pebblemill. If lacquer is being manufactured, the liquid from the mills

is sent to a separate building where additives are incorporated

and the resulting mixture is pumped into drums.

For products other than lacquers, the mixture is pumped from

the mixing station or from the mills to one of several letdown

tanks where additives, tint, resins, and solvent (or water) are

added. The viscosity, dry gloss, translucency, color, and other

physical properties of the product are tested in the laboratory

and adjustments are made as needed. The product is pumped

from the letdown tanks through filters to an automated filling

unit or gravity-fed to drums and tankers.

An abbreviated process flow diagram is shown in Figure 1.

Existing Waste Management Practices

This plant already has implemented the following techniques to

manage and minimize its wastes:

• When possible, cleaning solvents are reused in paint formulation.

• Plastic liners are used in steel pails to reduce cleaning

wastes.

• Obsolete products and products returned by customers are

blended into new products when feasible.

• Plant personnel are evaluating the possible purchase of a

distillation unit for the recovery of spent solvents that are

currently shipped off-site.

Waste Minimization Opportunities

The type of waste, 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 waste minimization that the

WMAC team recommended for the plant. The minimization

opportunity, the type of waste, the possible waste reduction

and associated savings, and the implementation cost along

with the simple 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 financial savings of the minimization

opportunities result from the need for less raw material and

from reduced present and future costs associated with waste

management. Other savings not quantifiable 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 for each opportunity

reflect the savings achievable when implementing each waste

Solvents

Pigments,

resins

Liquid

pre-batch

Dry

pre-batch

Solvents & resins Mixing or water Additives

Letdown,

tint, make-up

Sand-mill or

pebble-mill

Lacquer

production

Gravity

fill

Filtration and

automatic filling

Product to

shipping

Product to

shipping

Product to

shipping

Nitrocellulose

Ethylcellulose

Additives

Figure 1. Abbreviated process flow diagram.
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Table 1. Summary of Current Waste Generation

Waste Management Annual Quantity Annual Waste

Waste Generated Source of Waste Method Generated (lb) Management Cost1

Spills and leaks Various processes including

 batching and mixing Harden onto floor 6,320 $3,160

Contaminated solvents Various processes including

 lacquer production and letdown Shipped offsite 325,950 187,540

Evaporated solvents Pre-batch and mixing Evaporates to plant air 25,300 12,130

Off-specification paint Letdown Air dried; landfilled 2,200 4,215

Latex sludge Tank cleaning Shipped offsite 208,330 22,780

Solvent-based paint sludge Tank cleaning Shipped offsite 17,520 4,200

Reclaimed solvents Various processes including

 lacquer production and letdown Reused in process 180,000 2,150

Raw material storage bags Pre-batch Landfilled 49,000 430

Spent filter cartridges Filtration and filling Air-dried; landfilled 18,000 320

Raw material drums Pre-batch Reused in process 12,000 320

1 Includes waste treatment, disposal, and handling costs, and applicable raw material costs.

Table 2. Summary of Recommended Waste Minimization Opportunities

Annual Waste Reduction

Net Annual Implementation Simple Payback

Minimization Opportunity Waste Stream Reduced Quantity (lb) Percent Savings Cost (yr)

Implement a computer-based system for Spills and leaks 3,162 50 $114,000 $60,000 0.5

 batch scheduling, inventory, and waste Contaminated solvents 162,960 50

 documentation to reduce waste generation. Evaporated solvents 12,649 50

Latex sludge 104,160 50

Solvent-based paint sludge 8,760 50

Cover portable tanks whenever

 possible to eliminate solvent evaporation. Evaporated solvents 20,240 80 9,700 16,600 1.7

Extend the time for settling and decanting.

 Air-dry sludge in outdoor pools. Install a

 direct-heat countercurrent rotary dryer to

 reduce the volume of latex sludge

 hauled offsite. Latex sludge 124,160 60 6,450 12,000 1.6

Prevent drying of residual paint in

 portable tanks to reduce the

 need for caustic washing. Solvent-based paint sludge 5,840 33 960 0 Immediate
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minimization opportunity independently and do not reflect duplication of savings that would result when the opportunities

are implemented in a package.

This research brief summarizes a part of the work done under

Cooperative Agreement No. CR-814903 by the University City

Science Center under the sponsorship of the U.S. Environmental Protection Agency. The EPA Project Officer was Emma

Lou George.

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/600/S-94/007

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35