Maria Goetz
U.S. Army Tank-Automotive and Armaments Command
Warren, MI 48397-5000

One of the top ten chemicals found in the Toxic Release Inventory is ethylene glycol. Because of this statistic the United States Army has established a reduction goal for ethylene glycol disposal of 100%. One method of accomplishing this reduction goal is to recycle used antifreeze. Recycling antifreeze exists in the commercial sector and is gaining popularity in the Department of Defense (DoD) due to Executive Order 12856 which calls for improved recycling and reductions in waste generation. The Mobility Technology Center - Belvoir (MTCB), the qualifier for petroleum, oils, and lubricants within the DoD, approved two antifreeze recycling systems for DoD use that meet the specifications of MIL-A-46153. These systems were tested in a laboratory environment but not extensively tested in the field. To improve existing guidance and develop additional documents, the U.S. Army Environmental Center has funded the MTCB to select four Army sites and test these approved systems at the maintenance unit level for a period of one year. The goal at the conclusion of the test period is to develop installation, testing, training, maintenance and operating guidance documents that are easy to follow for users at the unit level. Purchasing and using the two approved antifreeze recycling systems has a payback period of approximately two years with minimal hazardous waste disposal.

In 1993 the MTCB evaluated commercial off the shelf antifreeze recycling machines to see if the processed coolant mixed with the required inhibitors meet the specifications of MIL-A-46153. Five different process types were evaluated at the MTCB including an ion exchange process, a vacuum distillation process, a chemical and pretreatment filtration process, an ultra-filtration process, and a reverse osmosis process. Each system was analyzed in the laboratory and two out of the five processes were compatible with MIL-A-46153. The systems compatible with MIL-A-46513 are the KFM Corporation Cool’r Clean’r Coolant Purification System ion exchange process and the Finish Thompson BE-Series Coolant Reclaimer Systems vacuum distillation process.

Four participating Army installations were given one approved antifreeze recycling system for the one year field evaluation searching for methods to make antifreeze recycling a simple as possible. Two installations received the KFM Corporation Cool’r Clean’r Coolant Purification System and the remaining two received the Finish Thompson BE-55C Coolant Reclaimer System along with the required inhibitors necessary for recycling antifreeze. Each participant was trained on how to operate the system by a sales representative from the respective corporation. During the one year evaluation, four vehicles from the installation’s maintenance motor pool were selected for the evaluation. These vehicles were drained of their existing antifreeze, the used antifreeze was recycled, and then poured back into the vehicle. A sample was taken before the antifreeze was put back into the vehicle and the characteristics of the recycled antifreeze were compared to fresh antifreeze. Samples were then taken every three months and were tested for reserve alkalinity, pH, freeze point, formate, glycolate, and total dissolved solids and again compared to characteristics of fresh MIL-A-46153.

During the one year field evaluation each participating installation kept records regarding suggestions on how to make recycling antifreeze as simple as possible. Each participating installation submitted comments to the MTCB that could help other installations starting up an antifreeze recycling program. Some suggestions included a start-up kit containing pH strips, a batter tester, drum stirrers, and clear plastic drums.

KFM Corporation Cool’r Clean’r Coolant Purification System (formally BG Products):

The Cool’r Clean’r Coolant Purification System (CCCPS) was tested by MTCB and verified to meet the specifications of MIL-A-46153. Formerly called the BG Products Cool’r Clean’r Coolant Purification System, this system operates as an ion exchange process. The CCCPS is a similar design to a kidney dialysis machine and removes all dissolved solids from the used antifreeze. The coolant is processed through the system at approximately 180 gal/hr and once processed, the waste coolant returns to pure ethylene glycol and deionized water. The only hazardous waste generated is from the spent filters. A sketch of the CCCPS is as follows in Figure 1.

Figure 1. Sketch of the CCCPS

During the one year site demonstration, samples were taken to see how the characteristics of the recycled antifreeze performed against characteristics of fresh antifreeze. With the CCCPS tests completed, the recycled antifreeze has met the MIL-A-46153 specification for reserve alkalinity, pH, and freeze point. Table 1 gives a breakdown of the quarterly samples.

Table 1. CHEMISTRY DATA FOR ONE CCCPS EVALUATION

Finish Thompson BE-Series Coolant Reclaimer Systems:

The BE-Series Coolant Reclaimer Systems were tested by MTCB and verified to meet the specifications of MIL-A-46153. The BE-Series comes in two different size units, BE-15C and BE-55C. The BE-55C

system was tested in this field evaluation at two Army installations. The BE Series Coolant Reclaimers operate as vacuum distillation units. Waste coolant is processed at flow rates between 1-3.2 gal/hr. Hazardous waste generated from this process is the distillation bottoms.

An Air Force installation discovered a process to reduce their hazardous waste disposal using the BE-Series Reclaimers. This installation purchased a BE-55C Coolant Reclaimer for recycling used coolant. The distillation bottoms from the BE-55C were collected and placed in a drum. This installation also purchased a BE-15C Coolant Reclaimer and recycled the distillation bottoms using this system. After each distillation bottom batch was processed, the installation collected the distillation bottoms from the prior batches and continued to recycle the distillation bottoms until there was no usable quantity left to process. This Air Force installation only disposed of 3 gallons of hazardous waste in one year using this process.

Figure 2. Sketch of the BE-Series Coolant Reclaimer

A sketch of the BE-Series Coolant Reclaimer System is found in Figure 2. Chemistry data for the BE-Series Coolant Reclaimer System is not available at the present time.

Antifreeze recycling is a cost effective alternative to purchasing and disposing antifreeze. With improved guidance for field use, installations should have no trouble recycling antifreeze on-site. The KFM Corporation Cool’r Clean’r Coolant Purification System and the Finish Thompson BE-Series Coolant Reclaimers generally have a payback period of 1-2 years depending on the amount of use.