Original Date: 11/03/1996
Revision Date: 01/18/2007

The Oak Ridge Y-12 Plant has implemented a recycling program for its primary water-based coolant for machining operations. The Y-12 Plant identified the problem of disposal of its coolants for machining operations in the mid-1980s. A search was conducted for a general purpose coolant without the problems of nitrosamines that were declared to be carcinogenic, and the replacement had to be recyclable. The coolant selected (not applicable to carbide grinding operations) was Trim Sol made by Master Chemical. Since this coolant could be used in 95% of the operations, the previously used five coolants could be consolidated into one.

Each machine has its own sump and undergoes periodic cleaning with the coolant recycled through a centrifugal system. The recycling produces sludge and tramp oil that must be disposed of as hazardous waste. The system also incorporates skimmers to remove oil from the coolant to reduce the bacterial growth.

The coolant undergoes quality assurance testing to ensure that it still meets the concentration, concentration ratios, pH, and corrosion criteria. Microbial contamination density and identification is performed. The measurements are simple but more sophisticated than most machining industries perform.

The coolant vendor is required to notify Oak Ridge Y-12 of any changes in the formulation of the coolant. Technical Support teams, consisting of Process Engineering, Chemical Engineering, a Corrosion Engineering Specialist, Microbiologist, and Industrial Hygienist, also have the support of the vendor for any problem resolution. The coolant eventually breaks down biologically or is contaminated and must then be disposed of. The recycling efforts reduce the amount of coolant that would have been disposed of from almost 5,000 gallons to 500 gallons per month resulting in substantial savings in replacement and disposal costs.

For more information see the Point of Contact for this survey.