United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-93/009 September 1993
&EPA ENVIRONMENTAL
RESEARCH BRIEF
Waste Minimization Assessment for a Manufacturer of
Rotogravure Printing Cylinders
Man/in Fleischman*, F. William Kirsch**
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 (EPA/625/7-88/003, July 1988).
The WMAC team at the University of Louisville performed an
assessment at a plant manufacturing cylinders for rotogravure
printing. A considerable amount of waste is generated by the
various plating operations in the plant. The plant operates its
own wastewater treatment system. The team's report, detailing
findings and recommendations, indicated that the most signifi-
cant cost savings could be realized by installing a batch still
onsite to recover xylene.
This Research Brief was developed by the principal investiga-
tors and EPA's Risk Reduction Engineering Laboratory (RREL),
Cincinnati, OH, to announce key findings of an ongoing re-
search 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
additional stress on the environment. One solution to the prob-
lem of waste 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
University of Louisville, Department of Chemical Engineering
University City Science Center, Philadelphia, PA 19104
who want to minimize their formation of waste but who lack the
inhouse expertise to do so. Under agreement with EPA's
RREL, the Science Center has established three WMACs.
This assessment was done by engineering faculty and stu-
dents at the University of Louisville's WMAC. The assessment
teams have considerable direct experience with process op-
erations 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 inhouse expertise in waste minimiza-
tion.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers, reduced
waste treatment and disposal costs for participating plants,
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 proce-
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 support-
Printed on Recycled Paper
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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
Chrome-plated, engraved, copper-plated steel and aluminum
cylinders for rotogravure printing are manufactured by this
plant. Approximately 70 employees operate the plant 6,240
hr/yr to produce nearly 4,000 engraved cylinders annually.
Manufacturing Process
The manufacturing processes used in this plant and the wastes
generated are described below.
Preparation of Used Cylinders
Customer-provided used cylinders are heated by a warm water
rinse over an open rinse tank. Next, rust and some of the
chrome plating are stripped from the cylinders in an acid
stripping tank which contains muriatic acid. The cylinders are
rinsed again over the open rinse tank. Then, the engraved
design, including the rest of the chrome and most of the copper
plating, is cut out of the cylinders using a lathe.
The waste rinse water is sent to the plant's onsite wastewater
treatment plant (WWTP). Spent stripping acid, which contains
heavy metals, is disposed of offsite as hazardous waste. Cop-
per shavings and turnings generated by the lathe are sold to a
recycier.
Preparation of New Cylinders
Purchased steel cylinders are cleaned with a detergent and
then degreased with a heated sodium hydroxide solution. Cyl-
inders are rinsed with deionized water. Spent rinse water is
drained to the plant's water treatment facility.
The purchased aluminum cylinders are washed with an en-
zyme cleaner and rinsed with a mixture of tap and deionized
water. Then the aluminum cylinders are rinsed with hydrofluoric
acid to make them less reactive prior to plating and rinsed with
water. Spent rinse water and acid are sent to the onsite water
treatment plant.
Nickel Plating of Steel Cylinders
Steel cylinders are nickel-plated in order to promote the bond-
ing of copper to steel during subsequent copper plating. The
heated plating bath contains copper sulfate, nickel chloride,
boric acid, and water. After the cylinders are plated, they are
rinsed with deionized water; spent rinse water goes to the
WWTP. The spent plating bath is disposed of as a hazardous
waste every two years.
Zinc Plating of Aluminum Cylinders
The aluminum cylinders are zinc-plated so that the copper will
bond to the cylinders during subsequent copper plating. So-
dium hydroxide, zinc oxide, and water make up the zincating
bath. Tap water which is used to rinse the cylinders following
zinc plating is sent to the plant's WWTP. The zincating bath is
dumped every three years and disposed of as hazardous
waste.
Cyaniding of Aluminum Cylinders
Aluminum cylinders are also treated with cyanide prior to cop-
per plating. The cyanide bath contains copper cyanide, sodium
cyanide, potassium sodium tartrate, and water. The cylinders
are cleaned with a brass brush, dipped in the cyanide bath,
and rinsed over a rinse tank with warm tap water. Wastewater
is sent to the plant's treatment facility. The cyanide bath is
dumped only as it becomes contaminated (about once every
four to five years).
Copper Plating of All Cylinders
All cylinders are plated with copper after processing as de-
scribed above. The plating bath contains copper sulfate, sulfu-
ric acid, and water. The copper anodes are enclosed in cloth
filter bags to reduce contamination of the bath with accumu-
lated sludge. Spent anodes are reclaimed offsite.
Plating bath wastes, residue from the baths, and spent plating
baths are disposed as hazardous waste.
After plating, the cylinders are rinsed with warm tap water over
a rinse tank; spent rinse water goes to the WWTP.
Lathing and Polishing of Cylinders
The cylinders are then processed in the lathe room. Imperfec-
tions in the copper plating are cut off with a lathe and the
plating is polished with a stone grinder. Copper shavings are
sold to a recycier.
The cooling and lubrication of the stone grinder with water
generates a colloidal copper sludge. The sludge is processed
in a settling tank where sodium hydroxide is used to precipitate
dissolved copper. The settled wet sludge is sent to a nonhaz-
ardous industrial waste landfill. Decanted water from the set-
tling tank and water from the grinder are sent to the WWTP.
Image Processing
While the cylinders are plated, customer-provided art work is
prepared for etching. First the artwork is photographed. Then
the colors in the artwork are separated, using graphic arts film
to produce one negative per color. The method used for further
processing the film depends upon the process by which the
image will be etched on the cylinder. If mechanical engraving is
to be used, the negatives are developed onto bromide films.
For the "direct transfer" process, positives are made from the
negatives.
Both liquid and solid wastes are generated by image process-
ing. Silver and some cadmium are removed from the film
emulsion when the negatives are washed in the fixing agent
solution. Rinse water from the film processors goes to the
electrolytic silver recovery units. Water from two of the proces-
sors goes directly to the sewer; silver levels in the effluents are
below the POTW limits. Overflow water from the other three
processors goes to the WWTP.
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Silver removed from the anodes in the electrolytic silver recov-
ery units is sent offsite to a reclaimer. Used films and used
negatives are also sent to the reclaimer.
Mechanical Engraving
Images are processed onto some of the cylinders using me-
chanical engraving. In this process, the bromide film is at-
tached to a scanning drum in tandem to the cylinder to be
engraved. A scanning device reads the image from the rotating
scanning drum and sends electronic impulses through a com-
puter to a diamond stylus which etches the rotating cylinder.
The completed cylinder is then sent for proofing. A small
amount of fine copper dust is generated and sold to a recycler.
Direct Transfer
Images are processed onto most of the cylinders using a
"direct transfer" method. Cylinders are scrubbed with an en-
zyme cleaner and rinsed with muriatic acid and softened water.
Then the cylinders are coated with a photoresist solution. The
positives produced are retouched to fill in any flaws and are
wrapped around the cylinders and exposed to a mercury lamp.
Light from the lamp exposes bare copper to create an image
on the cylinder. Cylinders then go to a bath where a xylene-
based developer is poured over the cylinders while they rotate
over a collecting basin. Blue dye is then poured over the
cylinders and the cylinders are rinsed with softened water,
dried briefly with compressed air, and wiped dry with paper
towels.
Wastewater from the initial rinse drains to the plant's WWTP.
Rinse water containing xylene is collected in a tank for phase
separation. The xylene phase is disposed of offsite as hazard-
ous waste and the water phase is sent to the WWTP.
Staging and Etching
Cylinders which were processed in the direct transfer area are
then sent to the staging area where an asphalt paint is brushed
onto the cylinders to protect areas which will not be etched.
Next, the cylinders are cleaned with a muriatic acid-methanol
mixture. The acid removes tarnish and the methanol provides
quick drying. Waste acid/methanol goes to the WWTP.
The cylinders then undergo an etching process in which cop-
per is removed by a reduction-oxidation process. A ferric chlo-
ride/bentonite clay slurry is applied to the rotating cylinders to
remove the exposed copper plating. Waste slurry is disposed
of as hazardous waste. Cylinders are then rinsed with tap
water; wastewater drains to the WWTP.
After etching, excess asphalt paint is removed with a naphtha-
wetted rag and excess photoresist is removed with citric-based
solvent on a rag. The rags are laundered and returned to the
plant by an outside company. Cylinders then undergo a quick-
drying rinse with a muriatic acid-methanol mixture. Waste rinse
solution goes to the WWTP.
Proofing
All engraved and etched cylinders go through the proofing
process. Lithographic ink is applied to the cylinders for one-
color proofs. Full-color proofs are then made for the customers
to check the accuracy of the cylinders. If necessary, a cylinder
may be re-etched using the same processes described previ-
ously. Between colors, ink is wiped off of the cylinders with
paper towels which go to a nonhazardous waste landfill. Waste
ink is disposed with waste xylene generated in the direct
transfer process.
Following the printing of full-color proofs, the cylinders are
cleaned with ethyl acetate and glycol thinner using rags. Rags
are cleaned by a local cleaning service and reused.
Chrome Plating
All cylinders are chrome-plated as a final process step. Cylin-
ders are first washed with an enzyme cleaner and rinsed with
hot tap water over an open drain. Wastewater goes to the
WWTP.
Tape is then placed over the cylinders' shafts to prevent them
from being plated. Cylinders are submerged in the heated
chrome bath which is composed of chromic acid, sulfuric acid,
and water. An exhaust hood over the plating tank carries
fumes and mist to a water spray scrubber. Wastewater from
the scrubber goes directly to the WWTP.
The cylinders are removed from the bath and rinsed with tap
water which drains into the tank. Cylinders are then immersed
in a second tank filled with tap water. Overflow from the rinse
tank goes to a chrome reduction tank.
Hydrazine is added to the chrome reduction tank to reduce
chromium (VI) to chromium (III) which then precipitates as a
hydroxide. The settled sludge is shipped offsite as hazardous
waste. Wastewater from the chrome reduction unit is treated in
the plant's WWTP. Plating bath correction waste is disposed
offsite.
The chrome-plated cylinders are then polished with fine polish-
ing paper, inspected and shipped.
An abbreviated process flow diagram for printing cylinder manu-
facturing is shown in Figure 1.
Wastewater Treatment Plant
The plant's wastewater treatment plant processes wastewater
to meet pretreatment requirements prior to discharging the
effluent to the POTW. The first treatment step is the addition of
sodium hydroxide to precipitate heavy metals. Next a flocculant
is added to promote the settling of metal hydroxide precipitates
in the settling tanks; overflow water goes to the POTW. The
sludge from the settling tank is disposed of as a hazardous
waste.
Existing Waste Management Practices
This plant has already taken the following steps to manage and
minimize its wastes:
• Copper shavings from the lathes, grinders, and polishing
machines are collected and sold to a recycler.
• Air agitation and constant circulation are used in all of the
plating tanks except for the zincating tank to minimize drag-
out.
• Cyaniding of steel cylinders has been replaced by nickel
plating because of concerns over cyanide in the effluent
going to the POTW.
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Oeionized water is used in nickel plating in order to minimize
the amount of sludge generated.
Dry-film photoresist is used instead of chlorinated solvents in
the image processing area.
A brand of film containing a small amount of cadmium is used
to reduce the amount of cadmium in wastewater.
Silver is reclaimed from the anodes in the electrolytic silver
recovery units and waste film by a recycler.
Chromium (VI) is reduced to chromium (III) before disposal.
The plant operates its own wastewater treatment plant.
Waste Minimization Opportunities
The waste streams currently generated by the plant, the man-
agement methods applied, the quantities of waste, and the
annual treatment and disposal costs are given in Table 1.
Table 2 shows the opportunities for waste minimization that the
WMAC recommended for the plant. Current plant practice, the
proposed action, and waste reduction, savings, and implemen-
tation cost data are given for each opportunity. The quantities
of waste currently generated by the plant and possible waste
reduction depend upon the production level of the plant. All
values should be considered in that context.
It should be noted that the economic savings of the Waste
Minimization Opportunities (WMOs) address only the raw ma-
terial cost avoidance and reduction of present and future costs
associated with waste treatment and disposal. Other savings
not quantifiable by this study include a wide variety of possible
future costs related to changing emissions standards, liability,
and employee health.
New cylinders
Aluminum
cylinders
Steel .
cylinders
Used cylinders
I
Rinsing
t
Zinc
plating
t
Cyaniding
Nickel
plating
i
r
Acid
stripping
I
r
Lathing
Copper
plating
.
Polishing,
r-**
Direct
transfer
Mechanical
engraving
»»
Staging
*•
Etching
t
Proofing
i
Finished **-
cylinders
Polishing
Chrome
plating
J
Additional Recommendations
In addition to the opportunities recommended and analyzed by
the WMAC team, several additional measures were consid-
ered. These measures were not analyzed completely because
of insufficient data, implementation difficulty, or a projected
lengthy payback as indicated below. 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.
• Recover copper plating chemicals from rinse water using
evaporation or ion exchange. High operating and implemen-
tation costs were predicted for this measure.
• Recover zinc from plating rinse water using electrodialysis. A
high implementation cost and low cost savings were pre-
dicted for this measure.
• Recover naphtha solvent from the rags used for wiping
cylinders. The amount of solvent recovered probably would
not justify the investment required.
• Investigate the possibility of using a cyanide-free solution
prior to copper plating
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. Environmen-
tal Protection Agency. The EPA Project Officer was Emma Lou
George. She can be reached at:
Figure 1. Abbreviated process flow diagram.
Pollution Prevention Research Branch, MS466
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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Table 1. Summary of Current Waste Generation
Waste Stream Generated Waste Management Method
Cylinder preparation
Spent acid stripping solution
Wash and rinse water
Nickel plating
Spent nickel-plating solution
Contaminated nickel-plating
solution/sludge
Rinse water
Zinc plating
Spent zinc-plating bath
Rinse water
Cyaniding
Spent copper cyanide bath
Rinse water
Copper plating
Spent copper-plating
solution and residue
Solution corrections
Spent copper anodes
Rinse water
Chrome plating
Solution corrections
Chromium sludge
Rinse water and fume
scrubber water
Polishing and lathing
Copper shavings
Copper sludge
Cooling and lubrication water
Image processing
Overflow water from developing,
rinsing, and silver recovery
Overflow water from developing,
rinsing, and silver recovery
Negatives and recovered silver
Direct transfer
Waste xylene and ink
Wash and rinse water
Etching
Hydrochloric acid/methanol rinse
Spent ferric chloride etch bath
Rinse water
Rags containing ink
and photoresist
Off site disposal
Treated onsite and sewered
Offsite disposal
Off site disposal
Treated onsite and sewered
Offsite disposal
Treated onsite and sewered
Offsite disposal
Treated onsite and sewered
Offsite disposal
Offsite disposal
Sold to a reclaimer
Treated onsite and sewered
Offsite disposal
Offsite disposal
Treated onsite and sewered
Sold to a recycler
Offsite disposal as non-
hazardous waste
Treated onsite and sewered
Sewered
Treated onsite and sewered
Sold to a reclaimer
Offsite disposal
Treated onsite and sewered
Treated onsite and sewered
Offsite disposal
Treated onsite and sewered
Cleaned and reused through
offsite service
Annual Quantity
Generated
495 gal
77, 500 gal
175 gal
110 gal
27,000 gal
18 gal
2, 600 gal
14 gal
2,600 gal
2,900 gal
1,430 gal
1,000 Ib
19,500 gal
550 gal
400 gal
320,000 gal
6,200 Ib
6,000 Ib
52,000 gal
338, 000 gal
507,000 gal
3,600 Ib
1,200 gal
52, 000 gal
3, 600 gal
2,730 gal
52,000 gal
104,000 units
Annual Waste
Management Cost
$760
990
690
440
350
70
30
380
30
5,350
2,750
(1,800)"
250
3,070
2,530
4,110
(11,160)*
**
670
370
6,5/0
(6,480)"
2,950
670
1,740
4,350
680
**
Mechanical engraving
Copper dust
Proofing
Paper towels containing ink
Rags containing ink
Waste water treatment plant
Sludge from settling tanks
Sold to a recycler
Conventional landfill
Cleaned and reused through
offsite service
Offsite disposal
1,872 boxes
78,000 units
11,000 gal
22,070
(Revenue received)
Cost not available
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Table 2. Summary of Recommended Waste Minimization Opportunities
Present Practice Proposed Action
Savings
Rinsing is done with open garden hoses.
Nickel plating rinse water is discharged
to the onsite waste water treatment plant.
Nickel plating rinse water is discharged
to the onsite waste water treatment plant.
Hydrochloric acid-methanol rinse from
the etching process is sent to the plant's
waste water treatment facility and causes
high biological oxygen demand
(BOD) surcharges.
Xylene waste from the direct transfer
process is drummed and sent off site for
disposal through a fuels program.
Xylene waste from the direct transfer
process is drummed and sent off site
for disposal through a fuels program.
Chrome-plating rinse water goes to a
chrome reduction unit which generates
sludge that is drummed and sent
offsite for disposal.
Install hand-held spray rinse guns for
rinsing in conjunction with acid stripping
nickel plating, zincating, copper cyaniding,
copper plating, direct transfer, etching,
and chrome plating. Reduced water usage
and increased return of solutions to
appropriate baths will result.
Use a reverse osmosis system to
recover plating chemicals; recycle
them to the plating bath. Use the
purified water for rinsing or make-up.
Rinse cylinders directly over the plating
bath to return drag-out to the bath.
Following the application of hydrochloric
acid, rinse the cylinders with hot
deionized water and dry them with
an air knife.
Ship waste offsite for xylene recovery.
Purchase a small batch still to recover
and reuse xylene. Ship still bottoms
offsite for disposal.
Install an ion-exchange unit to remove
bath impurity metals from the rinse water.
Recycle purified water containing
chromic acid back to the plating bath.
Estimated waste reduction = 90,200 gal/yr
Waste management cost savings = $1,160/yr
Raw material cost savings = $120/yr
Operating cost = $10/yr
Total cost savings = $1,270/yr
Implementation cost = $330
Simple payback = 0.3yr
Estimated waste reduction = 25,650 gal/yr
Waste management cost savings = $330/yr
Raw material cost savings = $2,520/yr
Operating cost = $540/yr
Total cost savings = $2,310/yr
Implementation cost = $5,000
Simple payback = 2.2 yr
Estimated waste reduction = 23,590 gal/yr
Waste management cost savings = $310/yr
Raw material cost savings = $1,110/yr
Operating cost = $20/yr
Total cost savings = $1,400/yr
Implementation cost = $60
Simple payback = 0.1 yr
Estimated waste reduction = 510 mg/l BOD
Waste management cost savings = $1,620/yr
Raw material cost savings = $2,000/yr
Operating cost = $2,400/yr
Total cost savings = $1,220/yr
Implementation cost = $410
Simple payback = 0.4 yr
Estimated waste reduction = 0
Waste management cost savings = $670/yr
Implementation cost = 50
Simple payback is immediate.
Estimated waste reduction = 1,050 gal/yr
Waste management cost savings = $1,900/yr
Raw material cost savings = $8,450/yr
Operating cost = $300/yr
Total cost savings = $10,050/yr
Implementation cost = $6,000
Simple payback = 0.6yr
Estimated waste reduction = 39,950 gal/yr
Waste management cost savings = $6,100/yr
Raw material cost savings = $2,660/yr
Operating cost = $670/yr
Total cost savings = $8,090/yr
Implementation cost = $9,240
Simple payback = 1.1 yr
•A-U.S. GOVERNMENT PRINTING OFFICE: I993 - 7S047I/MMI
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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
EPA/600/S-93/009
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
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