Pure Water
Case Studies
SAAB, a Swedish automobile manufacturer, uses a high-pressure cold water spray to clean aluminum engine
cylinder heads after machining. No detergent additives are used to aid cleaning. The water does contain a small
amount of corrosion inhibitor. The water is filtered and reused. The water is pressurized to 4,000 psig and exits
the nozzles at 500 mph. The cleaning system produces one clean, dry cylinder head every 48 sec.
Cold Water Cleans Machined Parts, Tooling & Production, pp. 38-39, June 1989.
ITT Telecom, Raleigh, NC, has eliminated TCA and methylene chloride based photoresist and replaced it with a
photoresist that can be clean with water. The new photoresist is glycol ether based and miscible in water. ITT
Telecom finds the new process reduces disposal cost, raw material cost, and operating cost. ITT is also benefiting
from improved product quality and production time.
Hunt, Gary, et al, eds., Elimination of Solvent-Based System Reduces Costs and Improves Product Quality at
Telecommunications Plant, Case Summaries of Waste Reduction by Industries in the Southeast, North Carolina
Department of Natural Resources and Community Development, July 1989, p. 49.
A manufacturer of brass keys (1.5 million/day) was using 1,1,1-trichloroethane (TCA) in a vapor degreaser to
remove a "medium grade cutting oil." They switched to a custom system using hot water high-pressure spray as
the wash. The keys are dried using high-pressure air. The system uses no surfactants or other additives. The water
is recirculated and cleaned with an oil skimmer. Annual consumption of TCA was 200,000 lb. The washer cost
$119,327 and had a payback of 1.08 years. The project is saving about $110,000 per year; $60,000 per year is
saved by the elimination of TCA and its associated disposal costs.
Case Study, Ilco Unican Corp., North Carolina Department of Environment, Health, and Natural Resources,
Office of Waste Reduction, Raleigh, NC.
Seagate Technology's Normandale facility manufactures read/write heads to be used in disc drives. Trays and
machine tooling are now cleaned using high-pressure deionized water, followed by hot air drying. This change in
cleaning saves over $130,000 annually in CFC-113 costs and reduces the CFC-113 discharge by about 23,000 lb.
Total capital cost to implement the aqueous system was roughly $100,000.
O'Keefe, Gene. Partial Elimination of CFC-113 Usage with the Use of Aqueous Cleaning at the Normandale
Facility of Seagate Technology, Application for the 1992 Governor's Awards of Excellence, Provided by
Minnesota Technical Assistance Program (MnTAP), Minneapolis, MN.
The Northwest Airlines Atlanta Maintenance Base is using high-pressure
water to remove the plasma coating from Pratt and Whitney JT8D turbofan
engine components. Previous methods involved premachining, abrasive
blasting, and chemical stripping. Using the high-pressure (20,000 to
55,000 psig) spray, 100% of the outer ceramic coating is removed. The
spray removes approximately 85% of the thermal barrier bond coat. Final
cleaning of the components still utilizes a chemical stripping solution.
Benefits include:
- Much faster (50-85%) removal of the plasma coating.
- Fewer parts are "out of round" than from the previous method.
- Elimination of 1,000 lb/month of aluminum oxide waste.
- Doubled the useful life of the thermal barrier strip solution.
- Eliminated a 700-gallon cyanide strip solution entirely.
- Low water consumption, approximately 2 gal/min during cleaning.
- Increased service life of the components due to minimal base metal
removal during cleaning.
Keene, Richard. 1992. Plasma Coating Removal via High Pressure Water
Stripping at Northwest Airlines Atlanta Maintenance Base, presented at
the 13th AESF/EPA Conference on Environmental Control for the Surface
Finishing Industry, Orlando, Florida.
Northern Telecom eliminated the use of CFC-113 for cleaning printed
circuit boards (PCB) at its Santa Clara, CA, facility. Semiaqueous,
saponified water, and 100%-aqueous (deionized) systems were evaluated.
The following factors led to the selection of deionized water as the
replacement cleaning solution:
- The 100%-aqueous cleaning system costs less to purchase, operate,
and maintain.
- The flux residues are completely water soluble.
- Soldering process yields are improved.
- Recycling the process effluent is simpler.
In 1992 the savings at the Santa Clara facility were approximately
$8,000 per machine per month.
Borek, Kevin. 1992. A Clean Break from CFC's, Circuits Assembly, 3(2):
43-46.
A manufacturer of miniature industrial controls in Geneva, Switzerland is now using water to clean its surface
mount assemblies. The old system used a stabilized CFC-113/methanol azeotrope in a vapor degreaser. The new
water only cleaning uses a high throughput batch system. The company has switched to a water soluble flux to
make water cleaning possible. No wastewater treatment is necessary and production costs (soldering, cleaning,
drying, and maintenance have been reduced 40%.
Conversion from CFC-113/Methanol Cleaning to Aqueous Cleaning for Medium- Sized Surface Mount Device
Assembler, Aqueous and Semi-Aqueous Alternatives for CFC-113 and Methyl Chloroform Cleaning of Printed
Circuit Board Assemblies, EPA/400/1-91/016, June 1991, pp. 74-75.
DuPont Chambers Works of Deepwater, NJ achieved a 98% reduction in a waste stream generated by washing a
process vessel with a flammable solvent. The DuPont Chambers Works site produces several grades of polymer.
During processing, polymer accumulates on the vessel walls, agitator blades, and baffles. Opening the vessel for
cleaning is difficult and time-consuming. In December 1991, the solvent was replaced by a high-pressure water
jet. The spray system consists of a special nozzle and lance connected to a high pressure water source (10,000 psi
at 16 gal/min) inserted through a flange at the bottom of the vessel.
This change reduces the incinerated hazardous waste load from .013 lbs/ lb of polymer product to 0.0001 lbs of
non-hazardous waste per pound of polymer produced. Barriers to implementation of the high-pressure spray
included concerns over safety. The system had to be designed to operate remotely and to completely enclose the
water jet. A specialized nozzle is used to reach all interior spaces. This system has been fully implemented.
Capital costs: $125,000. Net present value (EPA method) is $2,720,000 at a 12 percent discount rate; internal
rate of return is 181 percent.
Case Study #: 115. DuPont Chambers Works, Deepwater, NJ. 08203.
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