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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
solvent charge.  

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
acid.  

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
include:
      - alkyl phenol ethoxalate surfactants
      - water soluble organic solvents.  These are VOCs too.
      - phosphates.
      - some glycol ethers are problematic worker exposure/human health  
         issue.
      - 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
     
         choice.
       - in direct discharge to lakes, river and streams terpenes may not
   
        volatilize and could create a aquatic toxicity problem. Hopefully,
no   
         one discharges their degreasers in this manner.

Other concerns and  local issues could expand this list.

My contribution. end.

John O. Sparks
USEPA
Design for the Environment
MC 7406
401 M St. , SW
Washington, DC 20460
Telephone 202-260-1682
FAX 202-260-0981
e-mail sparks.john@epamail.epa.gov