Arlington County is seeking a $586,479 grant from the U.S. Department of Energy to study the feasibility of converting its refuse -- nearly 400 tons daily -- into almost 300 tons of fuel.

The county now takes its refuse to a Lorton landfill, said N. Ken Hook Jr., planning supervisor of the Department of Public Works.

"There is a limited capacity at Lorton," Hook said, noting that the landfill is expected to be filled to capacity in 10 to 20 years. "Once it's completely filled, the problems are going to be tremendous of where you go next."

With the program proposed for students, the county hopes it can save the $1.6 million a year it costs to haul refuse to Lorton, as well as generate revenue by selling the refuse-derived fuel (RDF). County officials estimated an RDF plant would cost $10-15 million to build, but said the exact costs and savings to the county would not be known until the feasibility study is completed.

Hook said the county expects the energy grant to be approved by the end of this month. If approved, the 16-month study could begin in March, Hook said, and an RDF plant could be operating by 1985.

The proposed program is similar to 37 other systems now used throughout the country. The major difference in the Arlington plan, Hook said, is that it would be simpler than other U.S. systems.

Under the Arlington plan, garbage, glass, fabric, paper and regular household trash would be shredded and placed in a drum that rotates at four revolutions a minute. Air would be injected into the drum to dry the material, and metal pieces would be removed. The resulting material, Hook said, would be a light, fluffy substance resembling shredded papper insulation, which could be burned.

County officials say the fuel would be odorless and could be used by the county or sold to private or public users, such as Vepco or Pepco.

"It's a process so economical and so technologically simple that even very small municipalities could use it," Hook said. "It's bases on the same process that has been used successfully for many years in Great Britian and numerous European countries, to compost refuse before landfilling."

Hook said one potential site for the RDF plant is the county "transfer station" at S. Eads and 31st streets, where refuse is brought before being transferred to Lorton, although other sites may be considered. Public hearings would be required before a site would be chosen.

Hook said a variety of financial sources are being considered for the plant itself, including private investments.

A spokesman for the Environmental Protection Agency said the EPA favors converting solid waste to fuels and has granted funds for similar projects elsewhere. The spokesman noted that any plant contructed by Arlington would have to comply with federal air-quality standards.