Used oil is the single largest non-watery liquid waste stream in New Zealand. An estimated 30 million litres are generated each year. (Approximately 60 million litres of lubricating oil are sold each year. About 50% is leaked, burned or otherwise lost during use.)
During use, oil becomes contaminated with a range of substances that are hazardous to human health and the environment, including heavy metals and polyaromatic hydrocarbons, some of which are potential carcinogens. Good management is required to ensure effective control.
Used oil recovery programmes have been in place for some years. The major oil companies operate nationwide collection networks and supply used oil to Milburn, New Zealand's Westport cement kiln, where it is burned at high temperatures. The burning of used oil in high temperature kilns is good practice environmentally because it deals effectively with contaminants. In some areas, local operators collect oil for low temperature burners (which often do not require resource consents), burning in asphalt plants and road oiling. An unknown but possibly small quantity of used oil is landfilled or dumped illegally in the environment.
The Ministry has worked on several projects dealing with used oil:
For more information:
Last updated: 17 September 2007