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A review of data in Table 8-1 suggests that an estimated 7,302 tons of wastes treatable by oil recovery are projected to be generated in the year 2000. Approximately 90 percent of this is generated by small quantity generators such as service station and printing shops. Wastes suitable for recycling include used motor oil from autos, marine crafts, agricultural and industrial machinery; industrial lubricating oils used for machinery; industrial "slop" oils from cleaning field storage tanks; and diesel oil used as fuel . As noted in DHS's third Biennial Alternative Technol -y Re ort (July 1986) , approximately 60 percent of the waste oil shipped off site in California is recycled. The primary use of recycled oil is as fuel ; a small amount is purchased for lubricant. As disposal costs rise and as recycling technology improves, recycling of used oil is becoming more economical . The costs of recycling a particular stream of used oil depends on the nature and concentrations of contaminants. Oil Recycling Methods Used oil can be recycled by one or more of the following technologies: • Ong-We Di ration - Typically oil is allowed to settle and is then subjected to screen filtration. Next, water and low molecular weight hydrocarbons are removed by dis- tillation. The final step involves sequential filtration processes. In general , water and low molecular weight hydrocarbons are removed by fractional and flash distil - lation. For special purposes, the oil may be volatilized and collected in a vacuum fractional distillation. Oil that is refined in this manner is generally used as a lubricant. • Chemical ireatment - This method involves chemically treating the oil to desolubilize metals and other contam- inants. One technique uses an aequeous solution of diammonium phosphates to remove metals from oil . The metals precipitate as metallic phosphates, which are insoluble in water and oil . Following filtration, the PJ9 9390502D.00D 11-12 Rev. 1 11/08/88