This story was updated at 9:17 a.m.
ALEXANDRIA, Va. -- About 10 miles outside of Washington, D.C., on a road dotted with storage units, parking lots and the occasional townhouse community, Covanta Energy's "resource recovery" facility looks like just another nondescript office building.
But enter the front door, take a sniff and its purpose becomes clear: This is where trash comes to burn.
More specifically, it's where Congress sends its trash -- about 5,000 tons every year of discarded coffee cups, empty chip bags, dirty plates and almost all the other refuse lawmakers, staffers and visitors toss daily. The 28-year-old facility then turns that into enough electricity to power about 250 homes.
The decision by House and Senate leaders to support such a facility has shone new light on an industry that has had trouble finding its niche. Is its place with conservatives, who are more likely to embrace established forms of energy production? Or liberals, who are pushing for more renewable energy use -- yet often shun waste-to-energy as too dirty?
"I'm not going to say we're perfect. But we're awful darn good," said Paul Gilman, a senior vice president with Covanta and the company's chief sustainability officer. "We set out to make energy from waste the cleanest, most reliable source of electricity."
Gilman, who was U.S. EPA's science adviser from 2002 to 2004, used graphs and statistics to set the stage for a plant tour and make a pitch: The country has a waste management problem, and facilities like Covanta are part of the solution.
Indeed, Americans generate about 250 million tons of trash each year. Eighty-seven million tons of that is recycled or composted. Most of the rest goes to landfills.
EPA considers burning waste for energy a better alternative to the landfill -- and a tool to combat climate change. A 2008 study from the agency found that turning trash into energy reduced carbon emissions by offsetting the need for energy from other sources -- like coal -- and reducing the amount of methane that trash produces when left to rot.
Gilman has turned that research into a tidy factoid: A ton of trash processed at a Covanta facility offsets a ton of greenhouse gas emissions.
But environmentalists aren't convinced. Several groups argue that trash-burning power plants emit pollutants such as mercury and lead, endangering those in the neighborhoods around them.
In 2011, the nonprofit Environmental Integrity Project released a report arguing that two facilities in Maryland -- one of which is run by Covanta -- emit more mercury, lead and other pollutants per hour of energy than the state's major coal-fired power plants.
On the whole, waste-to-energy facilities, which are small operations, emit far less particulate matter than large coal plants. In 2009, for example, three waste-to-energy facilities emitted 114 pounds of mercury of the 1,538 pounds emitted in Maryland.
'A question of material flow'
Allen Hershkowitz, a senior scientist at the Natural Resources Defense Council, is one of the more moderate opponents to waste-to-energy facilities. His outlook parallels that of Covanta; namely, waste-to-energy facilities may have a place in the waste management, alongside recycling.
But he pushes back against the notion that the government should invest in them or that they are the primary solution to the landfill problem.
First, he said, the country needs to address the fact that 80 percent of what people throw away is recyclable -- and not very combustible.
"This is a question of material flow," he said. "What material do we have, and where do they belong?"
He points to a 2009 EPA study that found that municipal solid waste is primarily made up of materials that can be either recycled or composted.
Plastics, for example, take up about 12.3 percent of waste, while food scraps are 14.1 percent. Paper is 28.2 percent. Waste also includes significant amounts of metals, glass and yard waste.
"Waste incinerators, waste combustion should be reserved for nonrecyclable, noncompostable material," Hershkowitz said, later adding: "We have to just stop just taking oil and gas, turning it into a product, using it once and burning it."
But Gilman's outlook is that Americans today still send most of their refuse to landfills, which emit more greenhouse gases than waste-to-energy facilities and often require long-distance hauls from home to burial.
"Do we need more sustainable waste management? Yes. We're the first to say yes to that," he said.
But waste-to-energy is the best solution now, he said.
"Is there a perfect energy producer?" he said. "Everything has its downside."
Company plays up recycling
On a recent visit to the Covanta plant here, Mike Ranga, the facility's business manager, showed off the plant like a proud father -- one who was used to giving tours. He passed around a heavy pipe used to hold steam, invited visitors to look down on the flames of a 2,000-degree fire and took off his hard hat to demonstrate the suction of an air vent.
The company aims to engage communities, getting ahead of any negative perception. It not only offers tours to anyone interested, but also donates to local charities and sends employees to volunteer to pick up trash.
It's a policy that has proven successful in Alexandria; earlier this year, the Arlington County Board unanimously approved a new contract with the plant with the possibility of an extension until 2038.
The facility's process is straightforward on the surface: Trucks dump trash into a large room, where workers use giant claws to feed it into one of three combustion chambers. The heat produces steam, which powers turbines, which in turn produces electricity and returns it to the grid.
But all along the way are pollution controls, from dry-activated carbon for mercury to fabric filters that remove particulates.
In all, it's a noisy, hot, smelly process, albeit one that stays within the confines of the facility.
The trash that comes in is varied. Compact discs, tree branches, food, bottles: All were evident. In a small room, a 6-foot magnet separated a propane tank from the trash, dropping it into a large dumpster. On an average day, it pulls out four dumpsters of metal, which the company then sells.
Covanta officials tout the importance of recycling, asserting that the existence of waste-to-energy plants encourages recycling rather than replaces it. Indeed, in other countries like Germany, the two work hand in hand. And Alexandra has a high recycling rate compared to the national average.
That didn't, however, apply to Congress when it decided in 2011 to send most of its waste to Covanta. The House canceled a composting program put in place when the chamber was run by Democrats and reintroduced polystyrene containers, which are thrown away rather than recycled.
Former Rep. Dan Lungren (R-Calif.), who was then chairman of the House Administration Committee, pointed out that stocking the House's cafeterias with corn-based utensils and lugging waste to an on-site pulper cost $475,000 annually, while saving the carbon footprint equivalent of one car annually.
"EPA and several others have said that this kind of energy recovery is among the cheapest and most efficient there is," Lungren said at the time. "This is one of the woefully underutilized technologies in America. And if we can give a boost to a technology that is underutilized, that's an added benefit."