The Treatment of
Emulsifiable Wastes Prior to Disposal
A. R. BALDEN,   Staff Engineer
Engineering Division
Chrysler Corporation
Detroit, Michigan
The wastes resulting from making an automobile are, in the main,
capable of treatment by known means. Soluble oils, emulsified cleaners, and
water soluble paints are capable of clarification by chemical treatment followed by air flotation. Chemical poisons such as cadmium, chromium and
cyanides can be destroyed or effectively separated from water. There are
means for destroying phenols. Certain bacteria can be developed that live
and thrive on this chemical even though phenols are used to kill bacteria in
oil emulsions. However, the equipment is expensive, so the best way to deal
with phenols is to avoid their use, if possible.
Phenols have been used to prevent the development of odor in emulsified
coolants and cleaners by destroying the bacteria living in this environment.
However, these bacteria thrive best under anaerobic conditions and circulation
and the resultant aeration of the coolant is often sufficient to hold the bacteria
in check. In other instances, non-phenolic but effective bacteriostats and
bacteriocides have been developed.
Another common use of phenols has been as additives in paint strippers.
As long as the only effective paint strippers available contained phenols their
use was allowed. At such time as a stripper became so loaded with paint
sludge that its usefulness was affected the alkali was decanted, the sludge removed and hauled to a dump, and the paint stripper restored to volume and
strength. However, the various suppliers of paint strippers were made aware
of the restrictions on the use of phenols and were requested to develop an
alkaline non-phenolic paint stripper. Approximately a year ago this was accomplished and the specification was rewritten to eliminate phenols.
Another example of the elimination of an unwanted waste involved an
engineering study of the methods for protecting some parts from corrosion.
The method in use was zinc plating using a cyanide zinc plating solution. A
decision had to be made to install facilities to destroy the cyanide or find
another method of protecting the parts in question against corrosion. Some
test work showed that certain components lent themselves well to stamping
from galvanized sheet and others could be phosphate coated and oiled without
losing functional effectiveness. The plating machine was removed a few years
ago and cyanide disposal is not a problem in this plant.
Some industries may re-use water more times than the automobile industry, but not many do. As an example, Chrysler used an average of 41 mgd of
water per day during 1959. Re-use of water was such that had such techniques
as recirculation not been employed an additional 22 mgd of water per day
would have been required. This savings is reflected in reduced waste treatment equipment costs as well as conservation of a valuable resource.
SOURCES OF WASTES
The organic wastes encountered in an automobile plant are many and
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