Reprinted from:
MODERN MACHINE SHOP Magazine
In just a few years, the disposal of spent coolants has become a significant factor in the operational cost of a plant. Shops which previously focused on the cost of buying coolants are now frequently paying more for disposal than they did for their purchase. Especially hard hit are small to medium sized shops, since they frequently lack the space, the capital or the technical personnel to utilize the exotic recycling or treatment capabilities which larger companies have turned to. Yet, their costs and liabilities are proportionately the same or greater.
One surface grinding and precision machine shop, Samco Incorporated, Anaheim, CA utilized a mobile coolant recycling service. In practice, an equipped truck would come to Samco about every 90 days and recycle the used coolant which had been collected. After recycling, the purified coolant would be returned for reuse.
At a charge of about $1,000 for each 1500 gallons, the service was not cheap, but it was less costly than the combined expenses of paying for disposal and replacement. However, after utilizing the service for some time, they realized that the recycled product really did not have the same properties as the original coolant. All too often, the processes which remove contaminant also remove or alter key elements of the coolant's formulation. In this case, they soon began to encounter significant deterioration in belt life, had to do an excessive amount of handwork, and were encountering a good deal of foaming.
At this point, E&K Sales, a local manufacturer's representative, presented an entirely different approach to the problem. It was pointed out that the used coolants are normally 97% water. If the water could be removed, the amount requiring disposal would be reduced to a mere 3% of the original volume.
To achieve this goal, a piece of equipment known as the WATER EATER was recommended. It is capable of removing from three to six gallons of water per hour from waste fluids. The equipment operates electrically, using either one- or three- phase 220 VAC (440 VAC is available as an option). The waste fluids are heated through the floor of the unit. At the same time, a power exhaust system continuously draws air across the surface of the heated liquid to speed evaporation and carry the water vapor out of the unit's stack. Should the unit run dry, an automatic shutoff prevents damage.
A unique feature is that it allows almost complete reduction of the liquid waste. The dry residue is simply scraped from the obstruction-free bottom of the unit periodically or the highly concentrated liquid which remains after many reductions may be taken out before becoming totally dry.
At Samco, the practice is to simply load the machine every 24 hours and boil down whatever waste fluids had accumulated. Having done this for more than a year now, they have realized a savings of $8,000. The company notes that it costs about 20 cents per gallon to eliminate the water content.
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