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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 That document has been superseded by the Facility Pollution Prevention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 Louisville performed an assessment at a plant

that manufactures rotogravure printing cylinders from new stock

and customer returns. Used cylinders and new cylinders undergo surface preparation, plating, and image transfer operations. The team’s report, detailing findings and

recommendations, indicated that process wastewater and wastewater treatment sludge are generated in large quantities and

that significant cost savings could be realized by recovering

plating chemicals from wastewater.

This Research Brief was developed by the principal investigators and EPA’s National Risk Management Research 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

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 also have 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 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 pollution prevention assessments require several site visits to each client served. In general, the WMACs follow the

procedures outlined in the EPA Waste Minimization OpportuWaste Minimization Assessment for

Rotogravure Printing Cylinder Manufacturing

United States

Environmental Protection

Agency

National Risk Management

Research Laboratory

Cincinnati, OH 45268

ENVIRONMENTAL

RESEARCH BRIEF

Research and Development EPA/600/S-95/007 July 1995

Marvin Fleischman*, LaTres Jarrett*,

Clay Hansen*, and Gwen P. Looby**

* University of Louisville, Department of Chemical Engineering

** University City Science Center, Philadelphia, PA

E AP
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nity 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 manufactures rotogravure printing cylinders from

new stock and customer returns. It operates approximately

7,500 hr/yr to produce over 5,000 engraved cylinders annually.

Manufacturing Process

Chrome-plated engraved copper-plated steel cylinders for rotogravure printing are produced by the plant. The principal raw

materials used are new and used steel cylinders and various

chemicals for stripping and plating. The processes involved are

cylinder preparation by nickel and copper plating, image processing, engraving or etching, and chrome plating.

Used Cylinders

Used cylinders requiring only re-chroming (approximately 10%

of the returned cylinders) are stripped of their existing chrome

layer using an acid stripping-solution. Then they are top-etched

with ferric chloride and/or re-chromed.

Used cylinders that are returned for a new design or are

otherwise uncorrectable are lathed to remove both the chrome

and the copper layers and are designated as “cutoffs”. The

cutoffs are then processed in the same manner as new cylinders.

New Cylinders

New steel bases and cutoffs are first degreased in a caustic

bath and rinsed. Following cleaning, the cylinders are nickel

plated and then copper plated. (Initial nickel plating enhances

the bond between copper and steel during subsequent copper

plating). After copper plating, the cylinders are polished using a

water-cooled grinding wheel.

While the cylinders are being plated, customer provided artwork is prepared for image processing in another area. Black

and white artwork is photographed and then scanned electronically. Negatives are produced for each color to be printed.

Further processing is determined by the manner in which the

image will be transferred to the cylinder.

If mechanical engraving is the transfer method to be used, the

negatives are developed onto bromide films which are attached to an optical scanning drum in tandem to the cylinder to

be engraved. The other method used is direct transfer etching

which requires photoresist application followed by acid etching.

After engraving or etching, the cylinders are inspected for

defects. Then a complete ink proof is made from the finished

cylinder. The cylinders that are deemed acceptable after proofing are chrome plated and then shipped. If the cylinders are

deemed unacceptable, they may be top-etched to add necessary depth for proper image transfer, proofed again, and, if

acceptable, chrome plated. Otherwise, the rejected cylinders

are lathed and the entire process is repeated.

An abbreviated process flow diagram for new cylinders is

shown in Figure 1.

Existing Waste Management Practices

This plant already has implemented the following techniques to

manage and minimize its wastes:

Rejected

cylinders Lathing Cleaning Nickel

plating

Copper

plating

Lathing,

polishing,

grinding

Proofing Finishing

Direct transfer

or

electronic engraving

Top

etching

Inspection

Chrome

plating

Image

processing Shipping

Artwork

Figure 1. Abbreviated process flow diagram for new cylinders.

New cylinders
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• An effort is made to collect copper scrap and send it offsite for

recycling.

• High-speed copper electroplating tanks are used to prevent

process and plating chemicals from clinging to the cylinders,

thereby extending bath life.

• Deionized water is used in all of the plating line rinses. Its use

eliminates the presence of calcium and magnesium ions and

thus reduces sludge formation.

• Diversion tanks are used to segregate the plating baths from

the rinse waters to prevent dilution and maintain bath composition.

• Silver is reclaimed from solution overflow in the developers

through a vendor-sponsored ion-exchange program. Silver

is also reclaimed from waste film by an offsite recycler.

• Dry-film photoresist is used in the direct transfer process thus

eliminating the chlorinated solvents frequently used in photoresist applications.

• Direct transfer is being completely replaced by electronic

engraving for image transferring. The direct transfer process

generates hazardous wastes such as xylene and ferric

chloride but electronic engraving generates only copper

dust, waste sandpaper, and towels.

• Fumes and mist from the chrome-plating tank are scrubbed

and recirculated to the plating bath.

• Raw materials are purchased in returnable containers and

finished products are shipped in customer-provided returnable boxes.

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 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 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 pollution prevention 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, 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.

• Install a sewer meter to measure the actual volume of

wastewater discharged from the plant.

• Extend the life of the acid-stripping solution by using an acid

purification unit.

• Regenerate spent ferric chloride etchant onsite or offsite by

electrolysis of the copper.

• Reblend waste inks offsite into a black ink that can be reused.

• Recycle containers in which copper anodes are received.

• Filter and reuse caustic cleaning solution.

• Reduce volume of trash discarded using a compactor.

• Recover spent butyl acetate used for cleaning in the proofing

process.

• Reduce drag-out losses to the onsite wastewater treatment

plant by using multistage countercurrent rinsing following

plating.

• Use an alternate reagent to complex the soluble metals in the

wastewater to obtain a reduced volume of sludge.

• Install a filmless electronic camera system that can transfer

images directly, eliminating the need for film developing and

finishing.

• Reduce drag-out losses by removing protective cones on the

cylinder ends directly over the plating tanks.

• Remove copper anodes from plating bath when not plating.

• Remove chromium (VI) from process waste streams using

granular activated carbon units.

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.
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Table 1. Summary of Current Waste Generation

Waste Generated Source of Waste Waste Management Method Annual Quantity Annual Waste

Generated (lb/yr) Management Cost1

Scrap copper Cutting and lathing of cylinders Bundled; sold to scrap recycler 16,000 -14,950

(revenue received)

Scrap copper Cutting and lathing of cylinders Mixed with trash; shipped to 16,000 170

nonhazardous landfill

Recovered silver from ion Image processing Sold to recycler 140 -1,780

exchange unit and waste film (revenue received)

Waste ink, xylene, and dye Proofing of cylinders and photo- Shipped offsite for fuels blending 7,150 7,700

resist development

Ferric chloride sludge Etching tank Shipped offsite for disposal as 1,420 1,100

hazardous waste

Wastewater treatment sludge Onsite wastewater treatment plant Shipped offsite for disposal as

hazardous waste 33,150 8,500

Evaporated solvents Cylinder cleaning Evaporated to plant air 18,490 0

Used filters Plating baths Shipped to nonhazardous landfill 4,220 included in waste managefilters/yr ment cost for miscellaneous

solid waste

Grinding sludge Grinding of cylinders Shipped to nonhazardous landfill 470 same as above

Miscellaneous solid waste Various plant operations Shipped to nonhazardous landfill 2,592,000 27,030

Process wastewater Cylinder preparation and plating Treated in onsite wastewater 1,003,000 29,9302

treatment plant; sewered

Process wastewater Grinding, etching, image process- Sewered 8,689,000 29,9302

ing, direct transfer, and polishing

Domestic wastewater Domestic uses Sewered 9,765,000 29,9302

1 WMAC estimates total administration and record-keeping costs associated with waste management of $2,400/yr, excluding wages. 2 Includes operation of onsite waste water treatment plant, sewer costs, and water purchase cost.
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Table 2. Summary of Recommended Waste Minimization Opportunities

Annual Waste Reduction

Pollution Prevention Opportunity Waste Reduced Quantity Per cent Net Annual Saving Implementation Simple

(lb/yr) ($/yr) Cost Payback (yr)

Improve collection of copper scrap

for offsite recycling. Currently, half

of the copper scrap generated is

disposed of trash. Scrap copper mixed with trash 01 —- $12,370 0 0

Install an electric furnace for

melting and ingoting of copper

scrap for reuse as anodes on-site.

(Degreasing of copper scrap may Scrap copper recycled 16,000 100 47,150 49,300 1.1

be required.) Scrap copper mixed with trash 16,000 100

Reuse the acid stripping solution

used for chrome removal before

treating it in the onsite Process wastewater (cylinder

wastewater treatment system. preparation) 5,860 50 2,960 0 0

Use a hot deionized water rinse

followed by drying with an air Process wastewater (etching

knife in place of alcohol for drying. and direct transfer) negligible —- 800 1,100 1.4

Replace cotton filters used in

conjunction with copper plating

with reusable ceramic cartridge

filters. Used filters 1,900 filters 45 36,530 400 .1

Collect, filter, and reuse cooling

water used for grinding. Process wastewater (grinding) 3,829,000 44 810 1,260 1.6

Concentrate copper-plating rinse

water and reuse as plating bath Process wastewater (cylinder

make-up. Recover and reuse plating) Wastewater 144,470 14 6,840 24,210 3.5

evaporated water. treatment sludge 4,590 14

Concentrate nickel-plating rinse

water and reuse as plating bath

make-up. Recover and reuse Process wastewater (cylinder plating) 165,110 16 4,900 24,210 4.9

evaporated water. Wastewater treatment sludge 1,100 3

Recover nickel from plating rinse

water using reverse osmosis and

reuse as plating bath make-up. Process wastewater (cylinder plating) 165,110 16 5,480 10,200 1.9

Reuse water. Wastewater treatment sludge 990 3

1 The same quantity of waste will be generated onsite.
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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-95/007