Abstract: A multi-stage apparatus and a process for recycling used engine coolant employs a combination of filtration, dissolved air floatation, centrifugation (hydrocyclone separation), semi-permeable nano filtration, reverse osmosis, and continuous deionization for separating ethylene glycol, with or without propylene glycol, and water from used engine coolant. The engine coolant is pre-filtered through a series of filters. The filters remove particulate contaminates. This filtered fluid is then subjected to dissolved air floatation and/or centrifugation to remove organic petroleum contaminants. Then, it is pressurized prior to being passed through semi-permeable nano filtration. The nano filtration separates the feed stream into a ultra filtration solution and a concentrated waste solution. The concentrate solution is returned to a centrifuged coolant tank for continuous circulation through the nano filtration device.