Antifreeze is used as an engine coolant and commonly consists of ethylene glycol or propylene glycol. Antifreeze breaks down over time and forms acids that corrode a vehicle’s cooling system. During normal use, antifreeze may become contaminated with traces of fuel, metal particles, and grit. Benzene, lead, and other hazardous constituents may cause used automotive antifreeze to be characterized as a hazardous waste.
DES believes that recycling is the preferred option for managing waste antifreeze and that the Universal Waste Rule will promote the recycling and proper management of waste antifreeze. Recycling methods for waste antifreeze include filtration, distillation, and ion exchange. Distillation and ion exchange restore the antifreeze to a high level of purity and some major vehicle manufacturers allow antifreeze recycled by these methods to be used in vehicles under warranty. Check with your vehicle manufacturers for more information. Simple filtration processes are not designed to remove dissolved contaminants. However, use of very fine filters or a series of filters, followed by the addition of chemicals, such as corrosion inhibitors, acid neutralizers and anti-clogging, to refortify the antifreeze can result in a useable product that meets American Society of Testing and Materials (ASTM) standards.