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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 That document has been superseded by the Facility Pollution Prevention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 printed labels and flexible packaging. Operations performed by this plant include printing cylinder

plating, printing cylinder etching, printing plate production, printing, and extrusion-coating-laminating. The team’s report, detailing findings and recommendations, indicated that waste

solvents are generated in large quantities and that the greatest

cost savings could be realized by installing a second distillation

unit to recover solvents from ink solids.

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 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.

Methodology of Assessments

The waste minimization assessments require several site visits

to each client served. In general, the WMACs follow the proceWaste Minimization Assessment for a Manufacturer

of Labels and Flexible Packaging

United States

Environmental Protection

Agency

Risk Reduction

Engineering Laboratory

Cincinnati, OH 45268

ENVIRONMENTAL

RESEARCH BRIEF

Research and Development EPA/600/S-95/004 April 1995

Richard J. Jendrucko*, Brian T. Hurst*, 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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dures 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 printed spiral wound labels for commercial use and flexible packaging for foods. It operates 6,240

hr/yr to produce over 14 billion units of product annually.

Manufacturing Process

The operations used by this plant include printing cylinder

plating, cylinder etching, printing plate production, printing, and

extrusion-coating-laminating. Each process is described briefly

below.

Cylinder Plating and Etching

Chrome is removed from used cylinders in an electrolytic dechrome unit and then the cylinders are lathed to remove the

previous copper-plated pattern. New cylinders and used cylinders accidently lathed beyond the nickel layer are then nickel

plated.

The cylinders are cleaned and copper plated. Next, the cylinders are lathed, polished, and cleaned prior to etching. A thin

coating of photoresist chemical is sprayed onto the copperplated cylinders. A plastic positive pattern is manually wrapped

around the cylinder which is then exposed to high intensity

ultraviolet light.

To develop the design onto the cylinder surface, dye is poured

over the cylinder. Cylinders are rinsed and dried. The cylinders

are then inspected for irregularities and hand-coated with staging lacquer.

Patterns are etched into the cylinders by immersing them in a

chemical solution. Lastly the photoresist and dye solutions are

removed with solvent-laden rags. Photoresist stripper is applied as a final step to remove all remaining solvents and

etching solution.

Once the design has been etched into the cylinder, the cylinder

is inspected and chrome plated. A set of printed samples is

produced for approval before printing runs in the rotogravure

printing line.

An abbreviated process flow diagram for cylinder plating and

etching is shown in Figure 1.

Printing Plate Production

For flexographic printing, another type of cylinder is prepared.

Used cylinders are reprocessed by first removing the previous

pattern and adhesive backing from them.

Multiple positive patterns of the desired pattern supplied by the

customer are aligned on a grid to insure proper position on a

photopolymer sheet. The pattern/grid combination is cut and

trimmed to fit the photopolymer sheet. Then, the sheet is

exposed to ultraviolet light on both sides sequentially.

Each sheet is washed in solvent to remove the areas of the

sheet not exposed to the ultraviolet light. Then, each plate is

positioned onto a steel-based cylinder and attached using an

adhesive backing. Printing samples from each cylinder are

produced, and accepted cylinders are transferred to the

flexographic printing area.

An abbreviated process flow diagram for flexographic printing

plate production is shown in Figure 2.

Printing

Rotogravure printing and flexographic printing are similar except for the type of ink and the printing cylinder used. Ink

concentrate is mixed in-house with various solvents (alcohol

for flexographic printing) by the supplier. The mixed ink is then

poured into a reservoir located on the press.

A printing cylinder is partially immersed in an ink-filled trough

and excess ink is removed. A continuous sheet of paper rolls

across the cylinder. After each ink application, the paper passes

through a heated tunnel to dry the ink prior to subsequent

printings. Varnish is applied to products that require it in a

similar manner.

The finished product is wound onto a core and removed from

the press. The roll of product is then rewound so that the

printed label will be on the outside. The roll is then placed onto

a slitter to cut large rolls that are several labels wide into

smaller rolls. The smaller rolls are reverse-wound again, packaged, and stored.

An abbreviated process flow diagram for printing is shown in

Figure 3.

Extrusion-Coating-Laminating

In the extrusion-coating-laminating line a flexible packaging

composed of up to five layers of material is produced. Various

combinations of paper and foil are combined to form the multilayer product. Plastic pellets for laminating are melted in extruders which are positioned over the paper in a laminating

machine. This process yields an outer lamination coating on

the other various layers. The paper is then cooled as it rolls

across a water-cooled cylinder. Once the product is removed

from the press, the roll is packaged and stored.

An abbreviated process flow diagram for this line is shown in

Figure 4.

Existing Waste Management Practices

This plant already has implemented the following techniques to

manage and minimize its wastes:

• Mixtures of ink solids and solvents are separated by distillation; recovered solvents are sold to an outside company.

• Plant personnel are evaluating a clean-up program utilizing

a water-based cleaner instead of alcohol for alcohol-based

ink printing runs.

• An onsite incinerator is used to oxidize volatilized ink solvents

so that evaporative emissions to the atmosphere meet federal guidelines.

• A computerized monitoring system for press set-up is used

to reduce paper waste.
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Waste Minimization 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 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

minimization opportunity independently and do not reflect duplication of savings that would result when the opportunities

are implemented in a package.

Additional Recommendations

In addition to the opportunities recommended and analyzed by

the WMAC team, several additional measures were considered. These measures were not analyzed completely because

of insufficient data, implementation difficulty, or a projected

lengthy payback. Since one or more of these approaches to

waste reduction may, however, increase in attractiveness with

changing conditions in the plant, they were brought to the

plant’s attention for future consideration.

• Clean solvent-laden rags onsite instead of shipping them

offsite for cleaning.

• Reuse treated wastewater in the preliminary stations of the

cylinder plating line prior to sewering.

• Minimize dragout from the plating bath by installing an array

of rinse spray nozzles above a “dead rinse” tank following the

plating bath. Install drag-out boards around the plating tank

to return dripping solution as cylinders are lifted out of and

moved away from the plating tank.

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.

Used cylinders

New Cylinders

Application

of

patterns

Photoresist

coating

De-chrome

unit Lathing Copper

plating Lathing

Nickel

plating Polishing

Ultraviolet

light

exposure

Cylinder

preparation

Staging Chemical

etching

Cleaning

and

stripping

Chrome

plating

Cylinders to Proofing

rotogravure printing

Figure 1. Abbreviated process flow diagram for cylinder plating and etching.
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Multiple positive patterns

Grids Photopolymer sheet

Alignment Cutting

and

trimming

Ultraviolet

light

exposure

Washing

Used cylinders Cleaning

Proofing Attachment Positioning

Cylinders to Floxographic Printing

Figure 2. Abbreviated process flow diagram for flexographic printing plate production.
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Ink,

solvents

Ink

blending

Varnish,

solvents

Varnish

blending

Ink

application Drying

Varnish

application Drying

Roll Slitting Rewind

inversion

Packaging Printed rolls

to storage

Printing

Figure 3. Abbreviated process flow diagram for printing.

Paper, foil Plastic pellets

Extrusion - coating - laminating

Lamination Cooling Printing

(if desired)

Edgetrimming

Packaging

Finished product to storage

Figure 4. Abbreviated process flow diagram for extrusion - coating - laminating.
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Table 1. Summary of Current Waste Generation

Annual Quantity Annual Waste

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

Copper and nickel turnings Lathing of cylinders Sold to recycler 3,900 $7,170

Evaporated solvent Cylinder plating and mixing of inks and varnish Evaporates to plant air 35,780 23,140

Solvent-laden paper towels Cylinder plating and etching Shipped offsite to landfill 560 30

Evaporated dye Etching of cylinders Evaporates to plant air 70 4,410

Obsolete patterns Etching of cylinders and flexographic printing Shipped offsite to landfill 5,670 300

 plate production

Solvent-laden cloth rags Various processes Shipped offsite and laundered for reuse 119,400 11,000

Adhesive backing Flexographic cylinder recycle Shipped offsite to landfill 1,200 60

Photopolymer trim Flexographic printing plate production Shipped offsite to landfill 1,200 60

Evaporated solvent Ink and varnish application in various lines Incinerated onsite 712,500 370,540

Ink-laden filters Printing in various lines Shipped offsite to landfill 11,440 620

Waste paper Various processes Compacted; shipped offsite to landfill 3,166,960 69,740

Evaporated alcohol Ink mixing in flexographic printing line Evaporates to plant air 1,790 1,790

Waste plastic logs Extrusion-coating-laminating Shipped offsite to landfill 178,420 9,260

Ink-laden solvent Various printing lines and parts washing Shipped offsite as hazardous waste 346,080 302,400

Ink-laden solvent Various printing lines and parts washing Distilled onsite; recovered solvent is 260,000 86,490

 sold to another plant for use as fuel

Decantation sludge Onsite solvent recovery system Shipped offsite as hazardous waste 37,490 $24,150

Still bottoms Onsite solvent recovery system Shipped offsite as hazardous waste 16,070 10,350

Extracted polymer Onsite distillation of spent plate wash solution Shipped offsite to landfill 1,060 4,690

Wastewater Various processes Treated in onsite wastewater 917,600 7,390

 treatment plant; sewered

Wastewater treatment plant sludge Onsite wastewater treatment plant Shipped offsite as hazardous waste 32,900 64,500

Spent lubricant Printing presses Shipped offsite 1,640 3,160

Miscellaneous solid waste Various processes Shipped offsite to landfill 96,310 5,000

*

Includes waste treatment, disposal, and handling costs, and applicable raw material costs.
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Table 2. Summary of Recommended Waste Minimization Opportunities

Annual Waste Reduction

Net Annual Implementation Simple

Minimization Opportunity Waste Reduced Quantity (LB) Per cent Savings Cost (yr)

Install a second distillation unit to recover all Ink-laden solvent —- 1 - $129,110 $21,480 0.2

solvent from ink solids for sale and to reduce

cost of offsite shipments of hazardous waste.

Install pumps, piping, valving, and computer Ink-laden solvent 54,030 16 88,940 2 288,800 3.2

hardware and software to automate ink and Evaporated solvent (not incinerated) 20,310 57

solvent mixing to reduce unnecessary waste Evaporated alcohol (not incinerated) 1,340 75

and evaporative losses.

Install a natural gas-fired sludge drying Wastewater treatment plant sludge 17,770 54 28,510 2 40,700 1.4

oven in the onsite wastewater treatment

system to further dry sludge for volume

reduction prior to shipment offsite.

Use recovered solvent for most cleaning Ink-laden solvent 204,120 79 11,560 2 0 Immediate

and discontinue use of virgin solvent

except for final wiping.

Use copper lathing waste instead of Copper and nickel turnings 2,920 75 1,510 2 0 Immediate

purchasing nuggets for copper plating tank.

Utilize existing cleaning tank lids to minimize Evaporated solvent (not incinerated) 600 2 900 0 Immediate

solvent evaporation. Evaporated alcohol (not incinerated) 1,200 67

1 The same total quantity of waste will be generated.2 bTotal annual savings have been reduced by an annual operating cost required for implementation.
BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/600/S-95/004