It takes about 20 people to process the trash at Prince George’s County’s recycling facility. (Harrison Smith/The Washington Post)

In a noisy warehouse in Capitol Heights, Maryland, the waste of more than 900,000 people zooms along a maze of conveyor belts. There is shredded paper, dirty plastic, old aluminum and shattered glass. Smashed soda cans bob amid coat hangers, telephone books and discarded lawn chairs — all of it hurtling through a sorting system that will allow most of these ratty old things to be recycled into new materials.

This high-tech, government-run facility is known as the MRF (pronounced “murph”), the Materials Recycling Facility. There are hundreds of places like it around the country, taking the waste you toss into recycling bins and sorting it into immense bales of paper, plastic, glass and aluminum that manufacturers buy and use to create new objects.

“We use recycled products all the time without even realizing it,” says Desmond Gladden, an environmental planner who oversees the MRF for Prince George’s County. “The carpet we’re standing on right now” — nothing fancy, the kind of woven carpet you might see at school — “is made from recycled plastic materials.”

Plastic goods such as soda and water bottles are separated at the MRF, Gladden explains, and then ground into tiny chips by the manufacturer, cleaned with an acid solution and woven into a polyester fiber to become carpeting. Glass bottles, broken or whole, can be melted down and turned into new bottles. Aluminum cans can be used to make new cans and other products.

It’s an almost magical transformation that helps the environment in two big ways: by reducing the amount of materials that are needed to make new products, and by reducing the amount of waste that ends up incinerated (burned to ashes) or sitting in a landfill.

One of the MRF’s resulting products: a bale of aluminum. (Harrison Smith/The Washington Post)

Different cities and counties recycle in different ways, accepting some recyclable items and not others. The Capitol Heights MRF sorts about 230 tons of waste each day, drawing from an ever-present pile created by dump trucks carrying discarded items. Most of the waste comes from Prince George’s residents, schools and businesses, but the MRF also serves Charles County and other area businesses.

In recycling lingo, it’s called a single-stream facility: Recyclables are dropped into one bin instead of being separated by material. That makes recycling easier: Gladden says that since the MRF converted to single-stream in 2007, adding supersmart sorting equipment, recycling has increased by about 30 percent.

You can recycle almost anything with a recycling symbol on it, Gladden says. Look for the three arrows that form a triangle: a symbol that the item is usually recyclable. On plastic goods, you might also see a number inside the arrows: “That refers to the type of plastic that’s being recycled,” he says. The numbers go from 1 to 7.

Last year, the MRF decided it would no longer accept plastic with the number 4, technically known as low-density polyethylene (polly-ETH-el-een). You probably know it as flimsy grocery bags.

An estimated 1 trillion plastic bags are used worldwide each year, and many of them end up in places such as the ocean, where they are harmful to the environment. It would be good if we could put them in the recycling bin, but Gladden says the bags jam the MRF’s sorting machines, and because they quickly become dirty, they can’t be sold to manufacturers to make new products. The best thing to do, then, is to reuse them — or buy reusable bags and avoid them altogether.

It takes about 20 people — manual sorters and machine operators — to keep the trash flowing at the MRF, moving it from dump trucks to sorting lines to bales of sorted goods and off to manufacturers.

The toughest job may be that of the presorters, says Jerald Boyd, who leads the facility’s operations. They’re the ones who are “armored up” with heavy gloves and face masks to pull things that can’t be recycled off the conveyor belts. What they find often isn’t pretty: toilet seats and cinder blocks, barbells and bowling balls. “But mostly,” Boyd says, “it’s just plastic bags.”

Correction : An earlier version of this story incorrectly reported the source of waste processed by the Prince George’s County Materials Recycling Facility. The majority of waste comes from Prince George’s, but the facility also processes discarded items from Charles County and other area businesses. This story has been updated.