Out of empty plastic detergent bottles, old scouring pads, dead rose bushes and discarded paper plates, Arlington County and the City of Alexandria are set to begin a $75.6 million joint venture to produce electricity.

The coffee grounds, Fudgsicle wrappers and orange peels that homeowners dump in their kitchen garbage cans today may be lighting the kitchen by the fall of 1987, officials from the two localities say.

What will make this eggshells-to-electricity transformation possible is a new high-tech facility the county and city will begin building May 3 on a 3.5-acre site on Alexandria's Eisenhower Avenue that now houses the city's old incinerator.

The new facility will devour 975 tons a day of almost everything but steel and glass at a blistering 1,450 degrees Fahrenheit to produce energy that will be sold to the Virginia Power Co.

Both the Arlington and Alexandria incinerators were closed in the 1970s, casualties of toughened federal and state air pollution standards, but the plants are still used as transfer stations where trash is compacted before being trucked to the Lorton landfill in Fairfax County.

By the early 1990s, the landfill will reach capacity if refuse continues being dumped there at the current rate of 1.3 million tons annually, including the 134,000 tons sent by Arlington and the 80,000 by Alexandria. Fairfax County, which is developing plans for its own "waste-to-energy" facility, Falls Church and the District of Columbia also truck their compacted trash there.

"We knew something was going to have to be done about Lorton 10 years ago, so we began looking at alternatives. If we had the luxury of good landfill sites which would meet needs for the next 30 or 40 years, we wouldn't need this new facility ," said N. Ken Hook, chief of Arlington's solid waste division. "But in urban areas, landfills are harder to find. So we will find more and more jurisdictions doing this as landfills become limited."

The 15-mile trek to Lorton is an expensive one. As a result, the closer-in new plant on an industrial site is expected to cut costs for consumers over its life expectancy of 35 to 40 years.

"Over the life of the project," said Dayton L. Cook, director of Alexandria's transportation and environmental services, "it will lower costs and provide an environmentally safe way to dispose of solid waste because the landfill sites are running out."

In Arlington, where the average annual cost to homeowners is just under $80 for trash pickup and disposal, Hook said, "If everything goes as well as expected, that bill will not increase and could, in fact, go down. It's hard to say at this time, though."

In Alexandria, Cook said, the homeowners are not charged separately for trash disposal because it is included in services provided through taxes. As of last Monday, however, the city had to begin paying a "tipping fee" to dump its waste at the Alexandria transfer station, which might cause a slight increase in costs for a while, Cook said.

That is because Alexandria is turning over ownership of the transfer station to Clark-Kenith Inc., the Atlanta-based contracting and engineering firm that is designing and building the new waste-to-energy facility, one of several it has done. A temporary transfer station will be built a block away to take refuse until the new plant opens in the fall of 1987, Cook said.

Cook and Arlington's Hook said that, upon completion of construction, a third-party equity will buy the building, but not the land, from the Arlington Solid Waste Authority and the Alexandria Sanitation Authority, the localities' oversight boards for the new facility. The building will then be leased to Clark-Kenith for about 30 years, and eventually returned to the ownership of the two localities. The third party is being involved to take advantage of tax laws so costs can be further cut. The new plant, which will actually cost $54.1 million to build, is being financed through the sale of industrial revenue bonds issued by Alexandria's industrial revenue authority. It would be the third such facility in Virginia, outside of Norfolk and Harrisonburg. Baltimore has a similar facility.

With the sale of the bonds last December, one of the last obstacles to the new facility was cleared. Earlier last year, the two localities had to clear a political hurdle few anticipated: getting an antitrust exemption from the Virginia legislature to run the plant.

In order to make the new facility successful and win financial backing, Arlington and Alexandria had to secure a "monopoly" on the disposal of garbage within their borders to assure there would be enough refuse to make the plant viable. Eventually, local legislators succeeded in quashing the effort of private refuse-haulers to deny the exemption.

Thomas M. Barnett, manager of business development for Clark-Kenith, said the new plant will not handle hazardous wastes, and will try to separate recyclable materials such as newspapers from combustible debris.

In the early years of operation, Barnett said, the daily load is expected to be around 700 tons, well below the plant's 975-ton capacity. As a result, other jurisdictions may be invited to truck their refuse to the new plant, thus reducing the overload on Lorton and extending its life.

Once the trucks begin rolling up to the new plant seven days a week, Barnett said, steam and electricity will be produced through the plant's waterwall mass-burn system in the following manner: the walls of the plant's three furnaces have water-filled tubes that will cool the furnaces as they incinerate trash and produce steam and hot water. The steam will turn the turbines that produce the electricity.

A byproduct of the system will be ash residue that will be trucked to Lorton. Importantly, Barnett and the local officials point out, by trucking ashes instead of compacted refuse there, the volume of refuse at Lorton will be reduced 90 percent. This could extend the landfill's useful life, now projected at less than 10 years, another 50 years. It would give the other local jurisidictions that dump their trash at Lorton more time to work on long-range plans for their own facilities, Alexandria's Cook said.

A 1978 federal law requires power companies to purchase, at reasonable costs, the energy produced at such plants, said Jim Burch, spokesman for the Virginia Power Co., formerly the Virginia Electric & Power Co. (Vepco).

The two localities and the power company are still negotiating prices. The steam, or hot water it produces, also could be sold in the private market. Officials say they don't expect the project to significantly reduce electric bills.

Still to be resolved in Arlington, said Hook, is the future use of the transfer station in Crystal City, which nearby homeowners consider an eyesore. Homeowners made nearly 18,000 trips there last year to dispose of their refuse personally, Hook said, so a smaller transfer facility may be considered to accommodate them.

"This is a very good solution" to the waste disposal problems urban areas are experiencing, said John G. Milliken, who, as chairman of Arlington's County Board also chairs the county's solid waste authority. "It will allow us to dispose of trash at less cost than might otherwise have been."

"Our commitment to this new plan is a commitment to the wave of the future," said Alexandria Mayor Charles E. Beatley. "I have little doubt that virtually every city in the country which is not undertaking such an activity will be very envious of our foresight in tackling this large problem with a long-range plan."