Atlantic Research Corp. of Alexandria is hoping to clean up financially by cleaning up PCBs.

Judith Kitchens, manager of ARC's environmental science and engineering department, has invented what the company calls the LARC process.

LARC stands for "light-activated reduction of chemicals." The process uses hydrogen and ultraviolet light to render PCBs, or polychlorinated biphenyls, harmless.

PCBs are suspected of causing cancer. But until that problem was uncovered in the early 1970s, PCBs were used in transformers, capacitors and related equipment because they are the best dielectric and heat-transfer fluid known. Dielectrics can sustain an electric field but do not conduct electricity.

Although PCBs no longer are used in transformers, equipment activated before the 1970s retains some of the PCBs even after they are drained and replaced, and the PCBs gradually contaminate the new dielectric fluid, according to Ed Kobylinski, ARC's senior environmental engineer.

Kitchens began working on the LARC process in 1976 and patented it in 1978. "We were looking at trying to clean up Kepone from the environment--specifically from the sediment of the James River," she said. The planned dredging of the river was canceled, so the LARC process couldn't be used there, but it is applicable to all halogenated organics--compounds treated with chlorine, bromine and iodine, including PCBs. So Kitchens turned her attention to the PCB problem.

The LARC process uses ultraviolet light and hydrogen bubbled through PCB-containing liquid to replace chlorines on the PCB molecules with hydrogen. This process, known as reductive dehalogenation, yields biphenyl--a powder that is toxic but can be disposed of or safely left in the dielectric--and sodium chloride, which is ordinary table salt. LARC-cleaned dielectrics can be reused.

The National Aeronautics and Space Administration wanted to solve the PCB problem in its transformers, said Charles Henderson, ARC's vice president in charge of research and technology. So, NASA awarded Atlantic Research a contract to build a LARC demonstration unit that can be transported by truck and treat at least 1,000 gallons of PCB-contaminated dielectric a day. The unit will be assembled over the next six months and then moved to Kennedy Space Center to be demonstrated for NASA and the Environmental Protection Agency. EPA then may grant ARC a permit to treat PCB-contaminated dielectrics.

Henderson said the company plans to construct more mobile units and sell a PCB-removal service.

According to Kitchens and Kobylinski, the pilot LARC unit works as follows:

* Solvents are mixed with the dielectric to draw out the PCBs.

* The solvents are run through a distillation column to concentrate the PCBs. Most of the solvent then is recovered to be used again.

* Small amounts of the dielectric remain with a high concentration of PCBs. This concentrated dielectric and a second solvent are exposed to ultraviolet light and hydrogen gas.

* The liquid is distilled again to recover the second solvent and the remainder of the decontaminated dielectric.

Henderson said ARC hopes the LARC process will generate $5 million to $15 million a year in revenue. an average money-maker for the company. Environmental work is less than 1 percent of ARC's revenue, "but we'd like to see it grow," Henderson said. About 15 of ARC's 2,000 employes work on environmental matters now, but construction and operation of four or five LARC units after completion of the NASA contract would double or triple that work force. He said that the company has invested $500,000 in LARC research and another $400,000 in the NASA contract.