Other pollution prevention opportunities may be available through commercial antifreeze recycling companies, check with you local or state pollution prevention office. The sludge that is filtered out is disposed of as hazardous waste. You can buy filtration units in several sizes depending upon your use. Distillation units heat the antifreeze and separate the water from the ethylene glycol. Through condensation, contaminants end up in a sludge that has to be disposed of as hazardous waste, and the solution is made into new antifreeze.
Most distillation occurs off-site and generally produces higher quality antifreeze than filtration.