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Used Oil Recycling

Used oil recycling

Used oil recycling is a procedure that involves reprocessing used motor oil so that it can be used again. Motor oil can be recycled indefinitely because the lubricant does not wear out. Recycled oil is cleaned of contaminants such as dirt, water, used additives, and fuel. Used oil may also contain toxic substances such as lead , benzene , zinc, and cadmium .

Recycling saves oil and helps the environment . According to the United States Environmental Protection Agency (EPA), 2.5 qt (2.4 l) of rerefined oil can be processed from 1 gal (3.8 l) of used oil. If not recycled, the gallon of lubricant from an oil change can ruin 1 million gal (3.8 million l) of fresh water, representing the annual water supply for 50 people. One pint (0.5 l) of used oil can create an approximately 1 acre (0.4 ha) oil slick on the surface of water, according to the California Integrated Waste Management Board. Crankcase oil accounts for more than 40% of the total oil pollution in harbors and waterways in the United States.

There are several markets for recycled oil. According to the American Petroleum Institute (API), a trade organization that joins with government agencies to promote the recycling of used motor oil from cars, trucks, motorcycles, boats, recreational vehicles, and lawn mowers, 75% of recycled oil is processed for use in industry, and 11% is used in space heaters in automotive bays and municipal garages. The remaining 14% is rerefined, returned to its virgin state, and again used as motor oil. The API reported that more than 640 million gal (2,422 million l) of motor oil were sold in 1997. People who changed their own oil bought 345 million gal (1,306 million l).

The API's Recycled Oil Web site includes instructions about collecting oil and where to take it for recycling. Oil should be drained from the car engine when it is warm (so that sludge flows out smoothly) into a pan that holds twice as much the crankcase. The drained oil should be poured through a funnel into a clean plastic bottle that has a tightly closing lid; the API recommends using a milk jug and cautions against using bottles that held bleach, cleaners, or automotive fluids such as anti-freeze (residue in those containers will contaminate the oil). The used oil should then be taken to a collection station. The API Web site has links to recycling information in every state and some Canadian provinces. Recycling services are provided by states, cities, and private companies. In addition, oil may be accepted at some service stations and oil change shops.

The next step in the recycling process is the collection of used oil by transporters who vacuum oil from service bays and collection center storage containers. The collected oil is tested for hazardous components. Oil that passes the test is mixed into a holding tank and taken by tanker truck to a recycler or a transfer station . At the transfer station, oil is held until it is taken to processors, rerefiners, or burners for heating.

Processors treat about 750 million gal (2,839 million l) of used oil each year, according to the API. About 43% of reprocessed oil is used by asphalt plants, 14% by industrial boilers at factories, 12% by utility boilers at electric power plants , 12% by steel mills, 5% by cement and lime kilns, 5% by marine boilers, 4% by pulp and paper mills , and less than 1% by commercial boilers that generate heat for offices, schools, and other facilities. The remaining 5% is marketed for other uses.

Rerefined oil is produced by a process that involves cleaning the lubricant of contaminants. After vacuum distillation, oil is hydrotreated to eliminate any remaining chemicals , then combined with additives to make virgin oil. Consumers who purchase rerefined oil should check the product for the API certification mark.

Used oil designated for specially designed space heaters helps to reduce heating costs at service bays and garages (it is not recommended for home use). In the United States, 75,000 space heaters are fueled by approximately 113 million gal (428 million l) of used oil each year.

Statewide recycling programs include Alabama's Project R.O.S.E. (Recycled Oil Saves Energy). It started in 1977 and is one of the nation's oldest programs. Project accomplishments include the collection of 9 million gal (34 million l) of used oil in 1993. In 1995 California's program was expanded to include an oil filter recycling program. More than 20 million filters are recycled annually in the state; recycling 1 ton (907 kg) of used filters yields 1,700 lb (771 kg) of steel and up to 60 gal (227 l) of oil.

[Liz Swain ]



American Petroleum Institute, 1220 L Street, NW, Washington, DC USA 20005-4070 (202) 682-8000, <>

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