Engine coolant is the liquid that cools off an internal combustion engine. It is commonly known as antifreeze because it is made with chemicals such as propylene glycol that are resistant to freezing in subzero temperatures. Although not considered toxic waste in the strictest definition of such, in virtually all cases, unless otherwise specified by a public waterworks utility, engine coolant must be recycled and cannot be poured into and disposed of in a residential drain or sewer system.
Drain used engine coolant into an empty container that can be sealed. Many councils have recycling programs available that will pick up sealed containers left out next to your regular rubbish bins.
Take a sealed container full of engine coolant to a hardware shop or car repair garage. Although many of these businesses will accept used engine coolant for disposal, call ahead to be sure.
Call your local council to find out about businesses or collection centres that will dispose of engine coolant.
Never pour engine coolant into septic systems or directly onto the ground.