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I was a partner in the study done by Katy Wolf and Mike Morris of IRTA evalua-
ting Water-Based Cleaners in the Auto Repair Industry. I am with the
Pollution Prevention and Technology Development in the Dept of Toxic
control. Other partners included the south Coast Air quality Management
District(SCAQMD) and the City of LA's Bureau of Sanitation. After this
was initiated, SCAQMD started to evaluate whether to change an existing air
regulation, Rule 1171, that would require the use of cleaning
materials containing no more than 50 grams of volatile organic compounds
(VOC) per liter. As it turned out, SCAQMD changed the regulation to require
just that which will go into effect 1/1/99.
Overall, Katy and mIke found that water-based cleaners worked effectively in
auto repair shops and were a viable option to mineral spirits. They tested
traditional sink-on-a-drum remote reservoir configuration, an immersion system
with a false sink, an enzyme unit, and a spray cabinet. The units were
steel, plastic, or stainless steel with a reservoir size from 15 - 40 gallons.
Tradeoffs: the water must be heated to make the cleaners more effective.
means increased electrical costs. Temperatures of 110 degrees F are common in
the immersion units and higher temperatures -- ranging from 140-180 F-- are
used in the spray cabinets. Mechanical action is more important in water
cleaning than mineral spirits. Most of the water-based immersion systems need
stronger pump pressure for mechanical action. The spray cabinet delivers pres-
sure of 15-60 psi.
Corrosion of parts was not a problem because there are rust inhibitors in the
water based cleaners. Drying of parts was not considered a problem. Katy's
study was a test and demonstration project during a time when there were not
many cleaning units available but still, most of the participants in the study
found that the units did a good job when the proper concentration of formula-
tion was used, i.e., 25-30 percent in immersion equipment and 10-15 percent in
spray cabinets. The equipment is now second generation, not traditional
mineral spirit sink-on-a-drums with an add on heater, which means they are
designed for water usage and thus work more efficiently.
One of the big pluses of using the aqueous cleaning systems is that workers
not exposed to mineral spirits via respiratory or dermal routes. Also, with
water-based systems that are formulated to reject oil, the oil can be removed
and the life of the bath can be extended beyond what if could be for mineral
spirits as the oil dissolved in mineral spirits eventually renders it useless
as a cleaner. Also, there does not appear to be a need to use an aqueous
cleaner with any VOC additives as they seem to work fine without them.
As to the management of the spent aqueous cleaning systems, there are a number
of issues that must be addressed.... at least here in California. The major
waste streams include the spent aqueous cleaners, oil skimmed from the units,
and the oil filters removing the oil from the units to extend the bath life.
Based on the lab results from Katy's study it was determined that most of the
time the spent aqueous cleaner will be considered a hazardous waste (RCRA and
non-RCRA, i.e., California only wastes) due to metals. Other contaminants
include PERC, xylene, and toluene from aerosal cans of brake cleaners used
the aqueous cleaning systems that end up contaminating the baths. So, in CA
the spent aqueous based cleaners must be manifested as a hazardous waste and
hauled by a registered hazardous waste transporter who must then deliver it a
TSD facility. This was routinely done before by the service delivering the
mineral spirits and picking up the old spent mineral spirits for recovery.
The oil filters were determined to be hazardous most of the time due to
So, these must be manifested and managed as a hazarous waste. The oil removed
from the aqueous cleaning systems however can be picked up by an oil recycler.
The sludge in the bottom of the cleaning units was also found to be hazardous
due to metals and would also have to be managed as a hazardous waste.
If anyone would like to receive a copy of the IRTA report entitled "Parts
Cleaning in Auto REpair Facilities: The Conversion to Water" Executive
#613, or the report (same title) #614 please send your mailing address via
fax (916)327-4494 or e-mail to Robert Ludwig, OPPTD/DTSC, P.O. box 806,
Sacramento, CA 95812-0806. If you have any questions, give me a call at
(916) 324-2659.The raw laboratory data is available but since there are only
a limited number, you will have to convince me why you need a copy.
E-Mail: HW1.RLudwig@ HW1.CAHWNET.GOV
*** Forwarding note from OWNERP2T--HWSMTP 07/31/98 11:11 ***
Subject: Parts Washers
There appears to be some options between the extremes of LOW FLASH
solvent based cleaners and aqueous cleaners. The low flash
cleaners seem to be preferred but are generating hazardous waste
and emissions. The big complaint with aqueous cleaners, as
mentioned in another message, is that they can create other
problems...corrosion on parts, slow drying time, poor cleaning
I would like to point-out some middle road options, as well as
advocate keeping one eye on new cleaning solutions. An important
element is the specific use for which the cleaning solution is
needed. One should definitely take this into account...even
aqueous solutions can become a hazardous waste in some situations.
There are some high-flash (>140) solvents that reportedly perform
very well and MAY eliminate the need for hazardous waste
management. (Sorry but I don't have specifics.) There are
reportedly solvent blends that accomplish the same purpose, again
pending actual use. I would think that the higher flash solvents
help to minimize VOC's. HAP's may be another issue on which to
keep one eye.
If there are multiply units in a facility NOT being used for the
same purpose, there may be an option on using different cleaning
solutions. Also, if multiple units are employed, there may be
options for reducing both the size and number of units, and
Change-out frequency can also be a problem if performed routinely.
Unit usage should be evaluated to determine if monthly change-outs
are needed, or perhaps a longer service interval. In several
cases, users extended change-outs to nearly double usage, and one
facility extended change-outs from every 4 weeks to nearly three
months. (I'm not quite sure how beneficial this may be for
emission reduction, but I'd like to think it is a positive
Some units are available with built-in filters that reportedly
extend the useful life of the cleaning solution. One type of unit
reportedly only requires periodic filter changes and the addition
lost fluid. Although I've heard the claim the filters can be
managed as non-hazardous, I still believe the actual usage would
determine the status of the filter. Again, emission reduction
still may be an issue.
I realize much of this does not address VOC issues. On a larger
than parts-cleaner scale, GE Transportation Systems, in Erie PA,
eliminated a solvent-based cleaning station (for train engines) in
favor of an aqueous-based cleaning system. VOC minimization was
one of the benefits. You may get additional information from the