Waste vegetable oil (WVO) is vegetable oil which is left over from other uses, most typically uses in the restaurant industry, such as deep fryers. There are a number of applications for WVO, ranging from rendering it for use in animal feed to processing it so that it can be used in alternative fuel vehicles. Although “waste” makes it sound as though this product is traditionally simply thrown away, waste vegetable oil is in fact a highly useful substance, and it can be quite valuable.
The most abundant source of WVO is restaurants, which typically collect WVO in large drums provided by rendering companies. When the drums are full, the rendering companies collect them and process the vegetable oil for use in cosmetics, animal food, and other products. Usually, the restaurant pays the company a small fee for the service, and the rendering company can generate a substantial profit from the oil it collects.
People who drive alternative fuel vehicles are interested in WVO as a source of fuel. It can theoretically be filtered and used as a straight fuel in vehicles which are equipped to run on vegetable oil, and it can also be processed to make biodiesel. Some conflict has arisen in some areas as a result of people collecting WVO without permission or authorization, and in a few cases people have been taken to court for theft as a result of taking oil from collection drums which belong to rendering companies.
In the case of an alternative fuel vehicle, WVO is most commonly used in “greasecars” which are designed to run on vegetable oil or a vegetable oil and diesel blend. These vehicles are usually custom fitted by their owners, and they require special maintenance to ensure that the engine stays in good shape. Waste vegetable oil can be used as fuel as long as it is from a good source, and it is treated properly.
Some drivers are under the impression that filtration to remove particulates is enough. However, WVO can also contain other impurities which can lead to engine problems, including water, acid, and chemicals. These substances are more difficult to filter out, and they can cause engine damage, incomplete combustion which leads to more air pollution, and other problems. For this reason, some drivers prefer to buy WVO which has been processed by companies which specialize in fuels for greasecars and other alternative fuel vehicles.
Recycling used vegetable oil for fuel may seem like a positive and logical step to take to improve the environment, but in fact using WVO can lead to increased demand for other oil products in other industries. This is because a sudden vacuum in the supply of waste vegetable oil can cause problems for companies which rely on it, forcing them to seek oils from other sources. This issue highlights one of the major problems with alternative fuels, with increased demand for alternative fuel causing unintended consequences in other areas.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.