Sometime today, a visitor to the Capitol will throw away a plastic foam coffee cup. Next week, a Virginia homeowner will turn on a coffeemaker.

Those two events will be linked by more than java: The Capitol trash will help power the Virginia home.

Starting today, Congress will send 90 percent of its nonrecyclable solid waste to an Alexandria, Va., power plant run by Covanta Energy, where it will be burned to create electricity.

It’s the latest chapter in an ongoing fight between Republicans and Democrats in the House over handling the Capitol’s trash. Since taking over the chamber this year, the GOP has ended former Speaker Nancy Pelosi’s composting program and replaced biodegradable dishware with plastic foam.

Advocates of the trash-burning initiative known as “waste-to-energy” say it’s a “win-win” that costs less while creating energy and reducing the need for landfills. These proponents include the Architect of the Capitol and leadership in the Republican House and Democratic Senate, who signed a contract last month with a vendor to haul waste to Covanta.

But not everyone’s convinced. Many House Democrats reacted lukewarmly to the proposal, saying that burning trash will inevitably put harmful toxins into the atmosphere, or that no program will ever be as effective as Pelosi’s “Greening the Capitol” sustainability program.

Paul Gilman, chief sustainability officer for Covanta, agreed a little with both sides, praising the Democrats composting but lamenting that their plan still used landfills.

“In an ideal world, you would have all three: recycling, composting and waste-to-energy,” he said.

The fight revolves around the approximately 5,300 tons of garbage produced each year in the Capitol. According to a formula provided in a report by BioCycle and Columbia University, that’s equivalent to the trash of a town with just more than 4,000 residents.

The trash will be taken to a plant in Alexandria that produces 180,000 megawatt hours of renewable electricity per year, which is used by Dominion Virginia Power to serve as many as 20,000 homes.

The modern-looking plant, built in the mid-1980s, is visible from the Van Dorn Street Metro station and is positioned within walking distance of an elementary school. It looks inconspicuous enough, and it’s hard to imagine that just 48 people work there full time, disposing of 350,000 tons of trash per year.

In fact, while cocooned within a quiet administrative office and conference room, a visitor might not realize that just past another door is the deafening noise of a mostly self-operated factory with many moving parts, including a fiery incinerator.

Hundreds of trucks come to the plant each day, parking on a loading dock of sorts, called the “tipping floor,” where they unload their cargo and drop them from a small height into a vast pit of garbage — the “holding pit.”

It’s reminiscent of a carnival game, except instead of a pit of multicolored plastic prizes to drown in, there are thousands of plastic trash bags overflowing with every kind of waste imaginable.

A machine-operated claw of massive proportions lowers into the pit and scoops up garbage — yes, like a claw scooping candy in an arcade game — and drops its loot into a refuse feed chute, where gravity pulls the trash down into the combustion chamber.

The plant looks much like the scene in the Pixar film “Toy Story 3,” during which Woody, Buzz Lightyear and friends have a near miss with fiery death in a waste-to-energy plant. In fact, another Covanta facility provided the sound effects for those scenes.

The burning trash is used to boil water, and the resulting steam drives a turbine, which generates electricity. The gases emitted through smokestacks are all filtered and cleaned before entering the atmosphere.

It’s hard to see this part of the process from within the heart of the plant, a maze-like structure with a drab green-and-yellow brick-and-concrete color scheme with metal grate stairs and blue linoleum floors.

But it’s happening all around and just with the switch of a lever. There are only five employees monitoring the plant’s activities at any given time, one of whom is stationed in the control room.

There, a chamber filled with computer monitors tracks in real time the levels of the various emissions produced at the Alexandria facility. If the levels ever go above safe limits, an alarm sounds and steps are taken to bring them down.

Toward the end of the process, any metals that were thrown away and brought to the plant — forks from a dining hall, bicycle wheels and car hubcaps, scrap materials from a construction site, among other things — are extracted from the waste-turned-ash by a spinning magnetized wheel. Visitors to the plant can see metal objects rise from the soot and attach themselves to the wheel with an incessant, clanging din. They are then taken to the plant’s “backyard,” where containers are filled with the scrap metal, waiting to be taken away to be repurposed.

This is the story of where Congress burns its trash. But for the people who run the Covanta plant in Alexandria, which also takes in the trash of nearby Arlington, it’s a story of a technology that they believe should be the premier form of sustainable trash removal in the United States.

They are very proud of their plant, the winner of local and industry awards. They give regular tours to school groups, environmental journalists and professionals, among them the Democratic and Republican staffers on the House Administration Committee.

Panel Republicans first planted the seed of going into business with a waste-to-energy provider, and in preparation for signing the official contract, staffs on both sides of the aisle took a grand tour of the Alexandria facility.

Salley Wood, the Republican spokeswoman for the committee, had just one word for the tour: “Impressive.”