INTERNATIONAL
CLEANER
PRODUCTION
INFORMATION
CLEARINGHOUSE
INTERNATIONAL
CLEANER
PRODUCTION
INFORMATION
CLEARINGHOUSE
CASE STUDY # 199
1. Headline: 1,1,1-Trichloroethane is eliminated from the
Production Process by Aqueous-based Cleaning at A
Fastening Parts Manufacturing Facility.
2. Background: See below.
3. Cleaner Production Principle: Process modification.
4. Description of Cleaner Production Application: The clean
technology involved initially reducing
1,1,1-trichloroethane use and finally eliminating its use
by installing aqueous cleaning systems.
Case Study Summary
Process and Waste Information: This facility manufactures
nails, staples, and the tools to drive these fasteners.
The fastening tools are made of aluminum, magnesium and
carbon steel. To produce these fastening parts, grinding,
milling, drilling, lathe working, heat treatment and metal
finishing operations are employed. Prior to many of these
operations, parts are cleaned in a cold application using
1,1,1-trichloroethane (TCA). TCA was being discharged in
the wastewater at levels twice as high as the allowable
limit. Absorbents used around the machine tools also
showed levels of TCA that prevented disposal in the
regular trash. The company decided to attempt to
eliminate the use of TCA from the manufacturing of
fastening tools.
A task force identified for potential causes for excessive
TCA cleaning wastes: too much availability of cleaners,
unnecessary dumping of TCA, lack of operator awareness,
and unnecessary parts cleaning. Initially, the firm
reduced the number of cleaning stations from 37 to 27.
Costs associated with dumping of cleaners were make the
responsibility of each department. Operators were
surveyed to identify TCA use and determine opinions for
alternatives.
The selected pollution prevention measure was to use a
heated tank with liquid agitation, provided the necessary
chip removal and oil removal systems were present. In the
machine maintenance areas, two mineral spirit cleaners
were installed and the company is in the process of
installing aqueous-based cleaning systems. At the time of
this case study, they had installed 13 aqueous washing
systems and two (2) mineral spirits cleaning systems.
They expect to have a total of 15 aqueous systems, which
are centralized within departments which will replace 37
former TCA locations.
Other processes implemented in addition to the processes
for reducing TCA included treating soapy water by oil
separation, and in-house pH neutralization. Also, a
precision grinder was replaced by an older piece of
grinding equipment which does not require virgin material.
A "procedure" (not further described) was also recommended
that would prevent the spoilage of coolants.
Scale of Operation: Approximately 6500 gallons per year of
TCA were used. No other measure of the scale of
operations was provided.
Stage of Development: The clean technology is in the
implementation stages - all equipment is not yet fully
installed.
Level of Commercialization: The technology is fully
commercialized
Material/Energy Balances and Substitutions:
Quantity Quantity
Material Category Before After
Waste Generation:
1,1,1-trichloroethane 400 ppb in waste- not
water discharge detectable
Feedstock Use:
1,1,1-trichloroethane 6500 gallons 0
Water Use: N/A N/A
Energy Use: N/A N/A
5. Economics
Investment Costs: The anticipated capital expenditures
during 1990-1991 on this project are $80,000. This
includes costs for aqueous cleaning systems, waste water
collection equipment, and equipment installation.
Operational & Maintenance Costs: $15,000 in utility costs
are required for heating and pumping aqueous fluids.
Payback Time: With an approximate annual savings of
$56,500 and $80,000 in capital costs, the pay back period
is approximately 1.4 years.
6. Advantages
A net savings of $7,000 is expected from reduced disposal
costs, since the disposal costs in 1988 were $9,000 and
they expect that the cost for disposal of separated oils
will be $2,000. In addition, the annual cost saving
associated with the disposal of absorbents no longer
contaminated with TCA is $34,000.
A net savings from replacing virgin TCA and aqueous
cleaners will be $7,000. This was calculated from the
difference in the 1988 cost of virgin TCA ($27,000) and
the 1991 costs for aqueous cleaning solution ($20,000).
Other processes implemented, in addition to the processes
for reducing TCA, included treating soapy water by oil
separation and in-house pH neutralization. The annual
savings from segregation and in-house treatment are
$20,000. The savings from changing to an older grinder
lead to an annual savings of $1,200 from reuse of the
coolant. The annual savings from preventing spoilage of
coolants are $1,300.
Overall, the potential savings from eliminating TCA is
approximately $56,500 per year (including the extra
utility costs presented below in 8.0).
There are also regulatory advantages that cannot be
directly quantified. Permit concerns associated with TCA
discharge were greatly diminished by successfully
negotiating with the regulatory agencies to tie the metal
finish discharge into the nearby town sewer system. The
company will no longer have to report under SARA for TCA
which will save considerable time. Eliminating TCA will
also allow the company to present a strong example to the
State and local communities that they are doing their part
to decrease overall emissions, thus increasing community
relations. Finally TCA air discharges will be eliminated.
This may be especially important since TCA has come under
intense scrutiny and regulation because of its ozone
depletion and air toxics potential.
7. Constraints
There is an extra electrical cost associated with heating
and pumping aqueous cleaning fluids equal to $15,000 per
year. TCA cold cleaning had no utility cost.
8. Contacts and Citation
Type of Source Material: EPA Conference Proceedings
Citation:
American Electroplaters and Surface Finishers Society,
Inc., and the Environmental Protection Agency; "12th
AESF/EPA Conference on Environmental Control for the
Surface Finishing Industry"; January, 1991; pp. 165-181.
Level of Detail of the Source Material: Additional
information is provided on the identification of the
problem and task force that decided on the solutions.
Industry/Program Contact and Address:
Kevin P. Vidmar, Div. Manager, Environmental Affairs,
Stanley Fastening Systems, Route 2, East Greenwich, RI
02818, United States.
9. Keywords: United States, USA, metal, plating, process
modification, trichloroethane, TCA, tank, coolant,
electroplating, ISIC 3400, ISIC 3471, water saving.
10. Reviewer's Comments: This case study was originally
abstracted form the document cited above for the US EPA's
Pollution Prevention Information Clearinghouse. In 1994
it underwent a UNEP IE funded review for quality and
completeness. It was edited for the ICPIC diskette in
August 1995.
DOCNO: UNEP 14 Document No.: 222-003-001C