EVALUATION OF A TREATMENT SYSTEM FOR
SPENT MACHINE COOLANTS AND OILY WASTEWATER
William D. Alexander, Manager
New Product and Market Development
American Colloid Company
Peter L. Maul, Engineer
Technical Services
Colloid Piepho, Inc.
Skokie, Illinois 60077
INTRODUCTION
In the United States alone there are many thousands of sources of oily wastewater. They
present an environmental problem of huge proportions, not only because of the sheer numbers of firms generating this type of waste but also because so many different industries
generate it. The largest volume producers are in the metalworking, food processing, and
vehicle washdown industries, but they account for less than half of the total volume [1).
One might anticipate that an oil pipeline company or an oil refiner would generate oily
wastewater, but who would suspect the same of tobacco companies, paper products companies, glass manufacturers and engine parts rebudders? Oily wastewater is generated by
virtually every major industry.
Generation of petrochemical wastewater is equally widespread. Many petrochemicals
form highly stable emulsions just as oil does. If petrochemical wastewater is included in the
total picture, sources now involve furniture producers, any manufacturers of products which
must be painted, plastics producers, even herbicide and insecticide manufacturers.
In all these industries there are, of course, large and small firms, but the small ones greatly
outnumber the large ones. Large numbers of small firms, coupled with the fact that processes generating typical oily wastewater tend to be small, results in flows per installation
in the 500- to 50,000-gpd range. Treatment systems involving heavy equipment are not
cost effective at such low gallonage levels [2].
Multiple step chemical processes are equally undesirable since most of them require specialized personnel, a luxury not affordable by small firms and not very cost effective for the
larger ones. Most oily wastewater or petrochemical wastewater generators would benefit
from a system which minimizes the use of equipment so that capital costs are held down,
and employs a minimum of treatment steps.
A treatment system has been developed that utilizes conventional equipment, designed
into a single compact unit, where complete treatment and sludge dewatering can take place.
The unique characteristic of the system is a montmorillonite-base rcactant which sequentially breaks emulsions, adsorbs, flocculates and then encapsulates the od or petrochemical
in one mixing vessel. The components of the formulation are compatible over a wide pH
range (pH 2 to 10) eliminating the need for acid or base additions as a pre-treatment. The
sludge resulting from treatment is highly stable and can usually be disposed of in ordinary
refuse landfills.
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