Where does your recycling end up?

New York City produces around 800 tons of recyclable materials every day. How is it sorted and transformed? Science Friday takes us behind the scenes at New York City’s largest recycling plant.


New York City produces around 800 tons of recyclable materials every day.

How is it sorted and transformed?

Up next, 'Science Friday' takes us behind the scenes at New York City's largest recycling plant.

You know, I think people think of recycling, that it's people bundling their newspaper, and Boy Scouts moving things, and people are kind of fascinated and I guess they're surprised at sort of the large, industrial, highly mechanized nature of the process.

My name is Thomas Outerbridge, and I'm the general manager for Sims Municipal Recycling.

Well, so we're in the business of receiving, processing, and marketing mixed recyclables that are collected by municipalities from their residence.

We service the five boroughs of the city.

It includes all rigid plastic, so everything from a laundry hamper to a toy to a plastic bottle, all glass, and all metal products from tin cans to bed frames.

You know, we have to basically take this mix and -- and sort it to a fairly extensive degree to turn it into a commodity.

If you didn't know what you were looking at, you'd think it's just garbage.

The materials accumulate on the tipping floor, right?

It's dumped there by sanitation or we unload our barges there.

We then have a front-end loader, big front-end loader that feeds a conveyer, and that will transport the material to the liberator.

The liberator is a slow-speed shredder.

Call it the liberator because the idea is really not to cut things up, but to really open bags and disentangle stuff.

People who live in high-rise buildings accumulate these bags in the basement.

Some people think plastic bags just because they're plastic they should be recycled, so they stuff bags full of bags, and then stick those in bags.

And so the liberator rips everything apart so that when we introduce it to the sorting equipment, the sorting equipment can do its job.

Disk screen are these disks, and they spin and they throw the material forwards, and there's gaps between those disks.

So anything that's less than 2 1/2 inches goes through the disk screen, and that is really targeting glass.

So it's removing 95% of our glass.

We send that to our glass plant in Jersey, where then it goes through a whole nother set of sorting steps, and then crush the remaining colored glass into an aggregate.

After removing the glass, the material passes underneath large drum magnets, which are big drums that turn and pick up all the ferrous metals.

Those ferrous metals then go to another trommel screen, where we separate the smaller ferrous metals, like tin cans, from the bigger metal furniture and things we get.

Then after we've removed the glass and the ferrous metal, we introduce everything that's left now on the belt to ballistic separators.

Two-dimensional material will lie flat on these paddles, walk up an incline, whereas three-dimensional material will bounce back.

So, now our three-dimensional material goes into a whole sequence of optical sorters.

Different materials have a different spectrum in near-infrared light that we can distinguish plastics by resin type.

So, it is looking for anything on that conveyor belt that is PET plastic, it's telling the air jets, here comes a PET water bottle.

We use air effectively to blow it off of the conveyor belt and separate it from the balance of the material.

Whatever is not ejected as PET, then travels on to the next optical sorter.

They go very, very fast.

They go much faster than a human being could possibly pick.

They're looking at 7 tons of material an hour.

Each step along the way, you're going after one more item until you're left with ideally nothing, but, of course, odds and ends that shouldn't be in there that end up as residue at the end of the process.

Most products are put into balers that make bales that -- similar to people might think of hay bales.

I mean, basically we compress the material for shipping.

And then as sorted commodities, we then ship out of here to customers.

People are absolutely buying this stuff.

It does go up and down with the market.

Yeah, we can do probably 800 tons a day.

The participation rate, I think, has gone up pretty significantly, so we're seeing more and more material.

We still know there's a huge amount still going to landfill, probably maybe 40% now of the recyclables that are meant to go in the recycling bin are still going into the trash.

So, please recycle.