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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 That document has been superseded by the Facility Pollution Prevention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 team at the

University of Tennessee performed an assessment at a plant

that manufactures gravure-coated metalized paper and film.

White coated paper purchased as a raw material is coated with

a water-based or solvent-based mixture, and a thin layer of

aluminum is deposited on the coating. Another coating is applied on top of the metalized surface. Rolls of film bought by

the plant also receive a thin layer of aluminum. The team’s

report, detailing findings and recommendations, indicated that

a large quantity of solvent evaporates from the plant’s processes and that a large quantity of unused coating mixture is

wasted. The greatest cost savings can be achieved by the

plant through the installation of an automated system for mixing and diluting coating mixtures.

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 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 reduction 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.

Waste Minimization Assessment for Manufacturer

of Gravure-Coated Metalized Paper and Metalized Film

United States

Environmental Protection

Agency

Risk Reduction

Engineering Laboratory

Cincinnati, OH 45268

ENVIRONMENTAL

RESEARCH BRIEF

Research and Development EPA/600/S-94/008 September 1994

Richard J. Jendrucko*, Thomas N. Coleman*,

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

The plant produces gravure-coated metalized paper and metalized polypropylene and polyester film for use in labeling and

wrapping food products. It operates 8,760 hr/yr to produce > 14

x 106 lb/yr of product.

Manufacturing Process

The plant’s products are manufactured from raw paper and film

received in bulk rolls. Other raw materials include water-based

and solvent-based coating mixtures, aluminum wire (for vapor

deposition coating), liquid nitrogen, and diluting solvents.

Diluting solvents (three different organic-solvent-based coating

mixtures and a water-based coating mixture) are received in

bulk quantities and stored. The organic-solvent-based coating

mixtures are diluted with methyl ethyl ketone (MEK) as required and transported to the pre-coater. Water-based coating

mixture is diluted with isopropanol and transported to either the

pre-coater or top-coater.

Raw white coated paper is processed in the pre-coater where

a coating is applied to enhance the gloss of the paper and

provide a good surface for aluminum adhesion during later

vacuum metalization. Two coatings are applied to the paper,

and in some cases, both sides of the paper are coated. One of

the three organic-solvent-based coatings or the water-based

coating is used for each coating application; the first and

second coating applications may or may not use the same

coating mixture. Following coating, the paper is dried in the

pre-coater oven.

Each coated paper roll from the pre-coater is transported to

one of two vacuum metalizers. Rolls of polypropylene and

polyester film are processed in a specialized vacuum metalizer.

A thin layer of aluminum is deposited on the paper and film

through vapor-deposition. About half of the metalized film is cut

to specification in the metalizer and sent directly to shipping.

The rest of the film is sent to the finishing, rewind, and slitting

area of the plant prior to shipping.

The metalized paper is transported to the top-coater where a

coating is applied to the metalized surface in the same manner

that the initial coating was applied in the pre-coater. The top

coat (supplied by the water-based coating) acts as a printing

primer and provides a clear protective layer. The coated paper

is dried in the top-coater oven and sent to the finishing, rewind,

and slitting area prior to shipping.

An abbreviated process flow diagram is shown in Figure 1.

MEK

isopropanol

Water-based and

solvent-based

coating mixtures

White coated

paper

Polypropylene

film, polyester

film, Al wire,

liquid N2

Metalized

paper and film

Top-coating

Mixing

Solvent

storage

Coating

mixture storage

Pre-coating

Vacuum

metalization

Finishing,

shipping

Figure 1. Abbreviated process flow diagram.

Existing Waste Management Practices

This plant operates an onsite solvent recovery still to recover

MEK from solvent wastes. Recovered solvent is used for diluting coating mixtures and cleanup.

Waste Minimization Opportunities

The type of waste currently generated by the plant, the source

of the waste, the quantity of the waste, the waste management

method, 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, 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

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 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.
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Table 1. Summary of Current Waste Generation

Annual Quantity Waste Management Annual Waste

Waste Generated Source of Waste Generated (lb) Method Management Cost*

Isopropanol spills and leaks Solvent storage 440 Shipped offsite $420

Organic solvent evaporation Mixing and supply drums in pre-coating 24,750 Evaporates to plant air 9,650

Water-based coating mixture spills and leaks Coating-mixture storage 680 Shipped offsite 720

Off-specification water-based coating mixture Mixing of coating mixture 6,250 Shipped offsite 6,760

Waste paper Pre-coating 960,000 Baled; sold to recycler 621,1801

Organic solvent evaporation Drying during pre-coating 1,740,000 Ducted to onsite incinerator; vented 940

Isopropanol evaporation Drying during pre-coating 489,000 Ducted to onsite incinerator; vented 260

Isopropanol evaporation Drying during top-coating 489,000 Evaporates to plant air 0

Isopropanol evaporation Supply drums in pre-coating and top-coating 3,560 Evaporates to plant air 1,070

Unused water-based coating mixture Cleaning of pre-coater and top-coater 5,360 Shipped offsite 5,790

Solvent-soaked cleaning rags Cleaning of pre-coater and top-coater 11,680 Shipped offsite; incinerated 26,640

Spent isopropanol cleaning solvent Cleaning of pre-coater and top-coater 17,460 Shipped offsite 18,440

Scrap aluminum Vacuum metalizer 45,000 Sold to recycler 64,030

Nitrogen gas Vacuum metalizer 9,631,320 Vented from plant 402,240

Polypropylene and polyester film scrap Vacuum metalizer 150,000 Shipped to landfill 289,210

Cardboard cores Vacuum metalizer 98,280 Shipped to landfill 840

Organic solvent evaporation Cleaning of pre-coater and top-coater 15,180 Evaporates to plant air 6,550

Spent organic solvent Cleaning of pre-coater and top-coater 3,560 Shipped offsite 2,570

Recoverable solvent Spills and leaks and off-specification 12,900 Reused onsite 1,500

 and unused coating mixture

Still bottoms Onsite distillation unit 30,110 Shipped offsite 35,790

Dry coating residue Onsite distillation unit 1,760 Shipped offsite 4,420

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

1 Net cost of waste stream. (Includes cost of handling waste plus raw material cost less revenue received.)
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Annual Waste Reduction

Net Annual Implementation Simple

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

Install a system to automate the Off-specification water-based coating mixture 6,250 100 $35,200 $45,000 1.3

 mixing and diluting of coating Unused water-based coating mixture 5,360 100

 mixtures to reduce unnecessary Still bottoms 8,140 27

 waste and solvent evaporation. Dry coating residue 480 27

Organic solvent evaporation 24,750 100

Isopropanol evaporation 3,560 100

Contract with an outside firm to Solvent-soaked cleaning rags —-1 —- 19,500 0 Immediate

 clean rags and return them to

 the plant for reuse.

Cover drums containing coating Organic solvent evaporation 12,380 50 5,360 250 0.1

 mixture during pre-coat and top- Isopropanol evaporation 1,780 50

 coat operations to reduce

 evaporative losses.

Extend distillation run time to Still bottoms 27,100 90 12,600 0 Immediate

 maximize solvent recovery

 onsite.

1 No waste reduction will result from implementation of this opportunity.

Table 2. Summary of Recommended Waste Minimization Opportunities
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United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

Official Business

Penalty for Private Use

$300

EPA/600/S-94/008