M-STEP Practice Test 9

Audio transcript: Where Your Recycling Goes

Welcome to the Riverside Recycling Center. Most people think recycling ends when the truck drives away. Really, that's where it starts.

Everything you put in your blue bin arrives here mixed together, and our job is to sort it. First, workers pull out things that don't belong, like plastic bags, which can wrap around our machines and shut down the whole line. Next, the materials pass over spinning screens. Flat items like cardboard and paper ride over the top, while bottles and cans fall through.

Then the machines get clever. A strong magnet lifts steel cans out of the stream. Aluminum isn't attracted to magnets, so we use a machine with a rapidly changing magnetic field that pushes aluminum cans off the belt into their own bin. Finally, optical sorters use light to identify different kinds of plastic and blast each one with a puff of air into the right container.

Here's why that matters to you: one greasy pizza box or one plastic bag can contaminate a whole batch. When that happens, the material may end up in a landfill after all. So recycle carefully. The machines are smart, but they can't fix everything.