Table 1. Summary of Current Waste Generation

Annual Quantity Annual Waste
Waste Stream Generated Source of Waste Waste Management Method Generated (Ib) Management Cost '
Solvent-soaked clean-up rags Equipment cleaning Shipped offsite as hazardous
waste for incineration 11,690 $37,010
Evaporated organic solvents Ceramic tape production Ducted to incinerator 19,610 37,080
Evaporated organic solvents Equipment cleaning Evaporates to plant air 500 190
Contaminated toluene Equipment cleaning Shipped offsita as hazardous waste 1,090 2,770
Evaporated organic solvents Tungsten paste production Evaporates to plant air 4,260 1,800
Evaporated organic solvents Laminating Evaporates to plant air 4,760 16,620
Jars containing dried tungsten paste Screening Shipped to landfill 2,140 2,460
Evaporated citric cleaner Screening Evaporates to plant air 980 2,140
Contaminated 1,1,1-trichloroethane Screen cleaning Shipped offsite as hazardous waste
for fuels burning 2,410 8,420

Evaporated 1,1, 1-trichloroethane Screen cleaning Evaporates to plant air 3,340 1,940
Cleaning rags Screen cleaning Washed onsite; raused 3,180 0
Waste adhesive/solvent Laminating Shipped offsite as hazardous waste 1,000 2,730
Rinse water Nickal plating and gold plating Treated in onsite WWTP; sewered 19,469,030 68,400
Spent acid solution Nickel plating and gold plating Treated in onsite WWTP; sewered 777,100 2,730
Spent plating solution Nickel plating Treated in onsite WWTP; sewered 5,910 20
Evaporated FreonTM Cleaning in nickel-plating and

gold-plating lines Evaporates to plant air 33,740 97,040
Contaminated FreonTM Cleaning in nickel-plating and

gold plating lines Shipped offsite as hazardous waste 4,930 34,330
Alkaline solution Nickel plating Treated in onsite WWTP; sewered 74,950 260
Spant gold solution Gold-plating Shipped offsite for gold raclamation 26,700 (152,740)?
Spent gold filters Gold plating Shipped offsite for gold raciamation 110 140
Rinse water and photochemicals Screen production Treated in onsite WWTP; sawared 374,950 1,320
Wastewater treatment sludge Wastewater treatment plant Shipped offsite as hazardous waste 35,610 18,010
Miscellaneous solid waste Various processes Shipped to landfill 8,790 6,050

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

2 Net credit received.


+ Rags wetted with citric-based cleaning solution are washed
in-house and reused.

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 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 pos-
sible 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 in-
clude a wide variety of possible future costs related to chang-
ing 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 du-
plication 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 consid-

ered. These measures were not completely analyzed because
of insufficient data, minimal savings, 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.

+ Compact the contaminated nickel plating solution fitters prior
to disposal to reduce the volume of space they occupy and
the associated removal cost.

Install a natural gas-fired dry-out oven to reduce the amount
of water contained in the sludge from the onsite wastewater
treatment plant.

Automate the measuring and delivery process of solvents to
the mixing chambers in the tape production area to reduce
evaporative losses.

Recover evaporated solvents from tape production, tungsten
paste mixing, and clean-up for reuse.

Substitute a nonhazardous cleaner for the solvent cleaners
used in the tape production and tungsten paste mixing lines.

Substitute a nonhazardous cleaner for 1,1,1-trichloroethane
used for clean-up in the screening area.

This research brief summarizes a part of the work done under
Cooperative Agreement No. CR-914903 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.


Table 2, Summary of Recommended Waste Minimization Opportunities

Annual Waste Reduction
Waste Stream —_—__ Net Annual Implementation Simple Payback
Minimization Opportunity Reduced Quantity (Ib) Per cent Savings Cost yn
Further purity the effluent + Wastewater 9,372,780 50 $28,750 $136,760 48
from the wastewater
treatment plant and
reuse it in the
plating rinses.
Install a tight-fitting lid Evaporated FreonTM 16,870 50 48,020" 10,200 0.2
and st
refrigeration coils on
FreonTM tanks to re-
duce evaporative losses.
Contract with an outside Solvent-soaked 0 0 18,190" 0 Immediate
firm to clean rags and clean-up rags
return them to the plant
for reuse. Spent clean-
ing rags will continue to
be generated but the
related costs incurred bj
the plant will decrease.
Install a distillation unit Contaminated 2,170 90 8,480 15,980 1.9
for the onsite recovery 1,1, 1-trichloroethane
and reuse of solvents. Waste adhesive/solvent 900 90
Contaminated toluene 980 90
Clean tungsten paste Jars containing dried 2,140 100 1,680" 3,070 1.8
jars and reusa them. tungsten paste

1 Total savings have been reduced by an annual operating cost required for implementation of this opportunity.


United States
Environmental Protection
Agency

Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268

Research and Development

EPA/600/S-94/012 September 1994

“EPA

ENVIRONMENTAL

RESEARCH BRIEF

Waste Minimization Assessment for a Manufacturer of Mountings
for Electronic Circuit Components

Richard J. Jendrucko’, Kelly L. Binkley’,
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. In an effort to assist these manufactur-
ers Waste Minimization Assessment Centers (WMACs) were
established at selected universities and procedures were
adapted from the EPA Waste Minimization Opportunity As-
sessment Manual (EPA/625/7-88/003, July 1988). That docu-
ment 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 ceramic mountings for electronic circuit com-
ponents. Several types of mountings, varying in size and num-
ber of ceramic layers and connectors, are manufactured by the
plant. Ceramic sheets are manufactured onsite and coated
with tungsten paste. The sheets are scored or cut, cured,
inspected, and nickel-plated, gold-plated, and brazed as re-
quired. The team’s report, detailing findings and recommenda-
tions, indicated that the waste stream generated in the greatest
quantity is wastewater from the plating lines and that significant
cost savings could be achieved by purifying and reusing the
effluent from the onsite wastewater treatment plant.

This Research Brief was developed by the principal investiga-
tors and EPA's Risk Reduction Engineering Laboratory, Cincin-
nati, 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.

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

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
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 gone by
engineering faculty and students at the University of
Tennessee's WMAC. The assessment teams have consider-
able direct experience with process operations in manufactur-
ing 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 minimiza-
tion.

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 participat-
ing plants. In addition, the project provides valuable experi-
ence for graduate and undergraduate students who participate
in the program, and a cleaner environment without more regu-
lations and higher costs for manufacturers.

&D Printed on Recycled Paper

>> D>


United States

Environmental Protection Agency

Center for Environmental Research Information
Cincinnati, OH 45268

Official Business
Penalty for Private Use
$300

EPA/600/S-94/012

BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No, G-35



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 identity 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 tech-
nological and economic information is developed. Finally, a
confidential report that details the WMAC's findings and recom-
mendations (including cost savings, implementation costs, and
payback times) is prepared for each client.

Plant Background

This plant produces ceramic mountings for electronic circuit
components. Approximately 600,000 mountings are produced
each year by the plant, which operates 4,160 hr/yr.

Manufacturing Process
Several types of mountings or “packages”, varying in size and
number of ceramic layers and connectors, are manufactured
by the plant. The unit operations used to produce the plant's
products are described below.

Ceramic Tape Production

A ceramic slurry is mixed from dry and liquid ingredients such
as alumina, talc, clay, silica, and solvent and then deaerated.
The slurry is then poured into a thin film on a conveyor to form
a tape and cured in an oven. As the tape exits the drying oven,
it is slit into strips of various widths, rolled onto cardboard
cores and stored until testing. Tape rolls that pass inspection
are pressure- and heat-stabilized. The rolls of tape are trans-
ported to a punch-and-cut machine in which a series of holes is
punched into the tape and the tape is cut into rectangular
sheets.

Tungsten Paste Mixing
Tungsten paste is produced from dry and liquid ingredients
including tungsten powder and solvent. The ingredients are
mixed together and the resulting mixture is dried overnight in
an oven. Finished paste is poured into small jars for storage
until required for production.

Screening

Ceramic tape that has been cut into sheets and punched as
described previously is loaded into a screening machine. A
vacuum is used to pull tungsten paste through the holes that
have been punched in the tape, thereby coating the holes’
inner surfaces. The sheets are then stacked and transferred to
another screening machine where a circuit pattern is automati-
cally screened onto the parts. The screened sheets are dried
with an ultraviolet light. About 85% of the product repeats
these last two steps up to three times to produce double-sided
and multi-layer packages.

The screened sheets proceed to a metal press where they
receive a dielectric coating as needed to prevent plating in
certain areas in subsequent operations. After receiving the
coating, some of the sheets undergo lamination. Some of the
sheets proceed directly to laminating after screening.

After lamination (to be described in the next section), the
products are scored for later separation or cut completely into
individual packages. (Products that do not require lamination
also undergo scoring or cutting.) The products are then con-
veyed through a high temperature kiln for several hours of
curing. After curing, the packages are inspected and those that
pass inspection proceed to the nickel-plating area (to be de-
scribed in a following section).

Laminating

Those sheets that require laminating are moved through a
booth where they are sprayed with adhesive. The individual
screens are stacked into groups of two or three, indexed, and
heat- and pressure-treated. Multi-layer packages are automati-
cally conveyed to a lamination press where heat and pressure
are again applied to bond the layers together. As described
previously, the products are then scored or cut.

Nickel Plating

The packages are nickel plated using one of three automated
operations—electrolytic, vapor deposition, or electroless. Pack-
ages that have been electrolytically nickel-plated are trans-
ferred to electrolytic gold plating, brazing, or to a sintering
furnace followed by electrolytic gold plating. The packages that
undergo vapor deposition are transferred to electroless gold
plating or to brazing. After electroless nickel plating, packages
are transferred to electroless gold-plating.

Gold Plating

Packages are gold-plated in one of two electroless plating lines
or in an electrolytic plating line. After electroless gold plating,
packages are taken to brazing or to inspection and shipping.
Packages from brazing and packages from electrolytic nickel-
plating are gold-plated electrolytically, brazed, and inspected
and shipped.

Brazing

Whether or not a package is brazed and at what stage it is
brazed depends on the product being produced. Pins and/or
seal rings are attached to packages which are then moved
through a brazing oven.

An abbreviated process flow diagram that depicts this plant's
processes for production of mounting for electronic circuit com-
ponents is shown in figure 1.

Existing Waste Management Practices

This plant already has implemented the following techniques to
manage and minimize its wastes.

+ Acitric-based cleaning solution is used instead of toluene for
clean-up in the screening area.

+ Most of the off-specification ceramic tape and cuttings from
ceramic tape is recycled onsite.

+ Toluene is decanted and reused in the cleaning processes.

+ Sodium hydroxide from alkaline cleaning tanks in the plating
process and hydrochloric acid solutions from plating are
used to adjust wastewater Ph levels in the onsite wastewater
treatment system.


Ceramic Punch Tungsten
‘p90 > and paste
production cut mixing
Hole ; Dielectric
filing Curing >| coating
| ry
—t} Screening Laminating
Scoring
4 Inspection = jg —____} Curing }<—_—_—_—} and
cutting
Electrolytic Ly) Sintering TF
Ly nickel- -
plating |—_—__—_—_——p|  Flectrolyse
gold-plating
am Lt
|+-—>| {¢—_———
Vapor
(am | TRC
—— Elect in
gole-plating §— [P| (sPeeton
jt Pe
. Packaging/
plating

Figure 1. Abbreviated Process Flow Diagram for production of mountings for electronic circuit components.