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RE: Parts Washers -Reply
I have been following this ongoing discussion of parts washers with
great interest. I am beginning to think that this would make a great topic
to start a P2 "CHAT ROOM ". I believe there are several hundred
thousand parts washers in small and medium sized businesses across
the country and eventually all will be affected by regulations.
The disruption of the classical sink on a drum degreasers is also
providing opportunities for the new entrepreneurial startup firms. The
enzymatic and bioactive aqueous units look very interesting as do the
low maintenance membrane aqueous technologies. It seems that the time
has come to introduce cleaner technologies to these small/medium
businesses, especially if it is at a reasonable cost.
Some solvent vendors are offering "closed loop " solvent parts cleaners
that reduce a facilities VOC emissions. These systems also have build in
solvent recycling abilities that extends the working life of the original
In terms of tradeoffs, I think the traditional sink on a drum business was
dominated by a few major companies that bundled reverse distribution
with their service offering - picking up the used solvent for recycling
and reclaiming the greases/oils etc for re-refining or use as fuel additives
and proper disposal of hazardous residuals. Assuming that this solvent
driven, reverse distribution network will deteriorate, alternative disposal
management schemes that service these small businesses are needed.
The tradeoff being : switching to low/no voc degreasers, but losing the
established solvent driven reverse distribution network. Both offer
significant environmental benefit.
A few technical comments:
Of the common chlorinated solvents, PERC is not a VOC (at least on the
Federal level) because it was delisted in the last few years. Likewise,
methylene chloride is exempt. TCE is a VOC. All are HAPs and OSHA has
issues with them as well. I don't think many - if any - aqueous cleaners
use sodium or ammonium molybdate as a rust inhibitor, but Moly/NO2 is
used for this purpose in cooling towers. The most common rust
inhibitors in aqueous formulas are amines of carboxylic acids and boric
The typical aqueous cleaner will have surfactants, water conditioners,
rust inhibitors and coupling agents. Some contain water soluble solvents
like glycol ethers and terpenes. I think ingredients to be discouraged
- alkyl phenol ethoxalate surfactants
- water soluble organic solvents. These are VOCs too.
- some glycol ethers are problematic worker exposure/human health
- EDTA and other strong chelates. These tend to hold heavy metals
over a wide pH range, alkaline and acid, and interfere with
precipitation in waste treatment. Gluconates may be a better
- in direct discharge to lakes, river and streams terpenes may not
volatilize and could create a aquatic toxicity problem. Hopefully,
one discharges their degreasers in this manner.
Other concerns and local issues could expand this list.
My contribution. end.
John O. Sparks
Design for the Environment
401 M St. , SW
Washington, DC 20460