What happens to a can, jar, bottle or box as it travels from your home to the recycling plant and beyond? Follow along as Knowable explores the opportunities and challenges facing the recycling industry today, speaking with Michael Taylor, who runs the Waste Management recycling collection facility in Elkridge, Maryland; researcher Marco J. Castaldi, chemical engineer at City College of New York; and a visit to the Covanta waste-to-energy plant in New Jersey.

Read more: Recycling meets reality

Video Transcript:

Marco J. Castaldi (professor of chemical engineering, City College of New York): “When you think about garbage, you and me, everybody in America, generates about four pounds per person per day — 300 million tons that gets generated a year. Then, right now the majority of it, more than half in the US, about 80 to 90 percent in other places, goes directly to landfill — and that’s crazy. If you look at what’s in the garbage, there’s energy there, there’s materials, and if you put them to a landfill, you don’t recover any of that.

“While there are these movements of zero waste, all data is showing that the waste is going to go up, and it’s not just because of population growth. Because of lifestyle, because we collect a lot of stuff. Prehistoric man — they couldn’t carry a lot of stuff, right? They didn’t have a house, it’s nomads — just take what you can carry. So therefore, if you look at, you know, what you consume, what you waste, that’s very much in balance a long time ago. Today, the stuff that we have is immense. Furniture, clothes and so on. And the point is, at some point, that will turn to waste.”

The waste stream

Marco J. Castaldi: “The waste stream is basically anything that nobody wants. The stuff that you and I throw away. So, typically it’s made up of plastic material, textile material, rubber, paper, glass, metal, food waste — organic waste — as well. And, you know, scientifically what we look at when we look at that is we say it’s pretty much everything in the periodic chart. So you could find gold in there, silver, copper. You find magnesium, sodium from salt, carbon. But you and I, who generate the garbage, we don’t separate it properly. So now that’s why the idea is, OK, well, we’ll just collect all of it and then we’ll bring it to a central facility and that central facility can then do the sorting.”

Materials recovery facility (MRF)

Michael Taylor (director of recycling operations, Waste Management, Elkridge, Maryland): “Most people don’t think about this aspect when they put their bin out at the curb. It just disappears. Well, this is what happens to it. We’re hardcore manufacturing, except we do it in reverse. We’re taking this sort of mixed-up stream of material and we’re de-manufacturing. So we’re breaking it down into individual components.

“We try to grab any material of value we can. We have basically 35 tractor-trailers worth of materials that we’re selling out of the back end of this plant every day. I view this operation much like somebody would view a Ford or Chevrolet manufacturing operation. They’re building cars. I’m building bales. I’m building bales of newspaper, bales of aluminum cans, bales of PET water and soda bottles. That’s our product, but that product is somebody else’s resource that they’re purchasing. So, I have to present them with a raw material that meets their standard.

“So behind you is the material basically presented as it’s come off of the truck — all mixed up. Up here, we’re looking for items that shouldn’t be here in the first place: plastic film, plastic bags. This is our probably best area of defense.

“Top 3 challenge would be contamination, contamination and contamination. Getting the right material in the bin. You would get a plastic grocery bag to start wrapping on one of those cogs, and it would like build up like a snowball. Plastic film, a garden hose, rope, propane tanks, helium tanks, medical materials — people put hypodermic needles in a milk jug, and then put the milk jug in the recycling bin. So we have those kinds of hazards that our employees are facing.

“We have difficulty with food contamination. An unemptied ice cream container that has melted tends to have the melted ice cream go across all the paper and it might be contaminating the entire load of recyclables that we’re trying to process. So if it’s a three-quarters-full yogurt container because you don’t like the taste, don’t put it in the recycling bin.

“Some of the biggest hazards for us are, really, the batteries. Why? Are the batteries recyclable? Sure! Batteries are recyclable, but not in this setting. A battery on these machines that gets crushed causes a spark, shorts it out and causes a fire. We have fires in our plants more than what we would ever like to see.

Newscaster: “Hundreds of firefighters still battling the blaze at a Willimantic [Connecticut] business that processes garbage and waste materials.”

Michael Taylor: “And everything has a battery. Your phone has a battery. Greeting cards — if you still use greeting cards, they have batteries. They make noise, they sing… Those sorts of things present such a fire hazard. It’s the flammable explosive that could shut this business down and hurt a lot of people.

“We’ve added more and more employees to manage the contamination that shouldn’t be there in the first place. Half of the people are there to remove the items that shouldn’t be there, not to make them go where they should go.

“You got four lines of paper, so paper goes over the top. Bottles and cans are going to drop through the screen, kind of like a pinball machine. There’s an overhead magnet grabbing all the tin cans. A fair amount of cardboard; I mean, that’s increased as people have done home shopping online and that sort of thing.”

A changing waste stream

Marco J. Castaldi: “The composition of the waste stream, it’s actually variable. Over the years, plastics have gone up huge amounts. Before the internet, everybody read their news on newspapers, everybody printed stuff out. Today, we get all of our news electronically, so the amount of paper mix has changed.”

Michael Taylor: “Eighty percent of what we received back in 2006 was newspaper. Now, today, that’s less than 50 percent of everything that we handle. There’s less readership, so there’s less newspaper out there, and it’s been replaced by plastics, by bottles and cans, by more cardboard. So a system that was designed around 80 percent newspaper is now receiving something that looks different than that, and we’ve had to adapt to that.

Marco J. Castaldi: “And this is now what becomes difficult, because all systems that try to process something need to be designed based on what’s the input. So if I’ve got a pure input of anything, I can design a system to extract what I need from it, and so on. But if that input is changing, well, now you have a little bit of an issue. Those material recovery facilities aren’t sitting still. They’re trying to adapt to it, but you can’t predict it.”

New sorting technology

Michael Taylor: “The technology that we’re using today is really optics-based, so we’re using near-infrared scanners, optical scanners to identify plastics. Program it for PET, it shoots the PET bottles off with an air jet when it sees it on the conveyor belt. Another optical scanner, that’s firing on HDPE [high-density polyethylene] does the same thing. Our newer plants that are being built are being equipped with AI-based robotics to do sorting technology.

“A flattened aluminum can is going to have an infinite kind of shape when it’s smashed. They’re not all going to look the same, so you have to let the technology learn what you want to be selecting on.

Economic factors

Marco J. Castaldi: “Let’s face it. Market forces and economics dictate what happens, so if a facility here or in Europe or anywhere takes in garbage, they get paid to take that in. Then they do their separation, and they get to sell the recycles. Whether that’s metal, glass, plastic, they sell that, so another stream of revenue. What they have left over, they can’t just pile it up. So if they’re going to send that to a landfill, they’ve got to pay to dispose of it. So that’s a revenue loss. But if someplace else says, ‘Ship it to me. I’ll buy it,’ and even if it’s a dollar a ton, well, that’s better than paying $20 a ton to dispose of it, right? You’ve saved $21 a ton.”

Michael Taylor: “Eight-four percent of what we process and manage today is actually material that’s going to go to a mill, get recovered and turn into a different product. About 16 percent of material that shouldn’t be here in the first place ends up going to disposal. In this particular operation, we’re a zero-landfill-based facility. Our residual — that material that shouldn’t be here in the first place — goes to a waste-to-energy facility in Baltimore.”


Marco J. Castaldi: “What everybody thinks, then, is: reduce, reuse, recycle, and I agree with that 100 percent. The problem is, practically, you can’t stop there, because not everything could be recycled. That’s where the energy extraction comes from. The waste to energy, if you will.”

Voiceover: “This is a couple days of people’s garbage in a community on Long Island.”

James F. Regan (Covanta Thermal Conversion Plant): “All that garbage that’s generated, we combusted in a boiler to produce electricity, and here we make enough power for about 75,000 homes. So the garbage you put to the curb is put to good use to generate electricity around the clock to power your home.”

Marco J. Castaldi: “The scale of garbage that we generate, the rate of garbage that we generate, can only be handled by two processes today: landfill and thermal conversion. People are against thermal conversion. And the perception in New York City and in many large municipalities and cities is waste-to-energy is bad — ‘it’s an incinerator.’ Incinerator is different than waste-to-energy, but ‘it’s bad, I don’t want this.’ And they think, ‘You’re going to burn the garbage? Are you crazy? That was what done so many years [ago]. We stopped ... didn’t we stop that?’

“Yes, and this burning is in a much more controlled environment. We’re extracting the energy, we’re getting the materials, we’re cleaning the emissions. So, very different.”

[screen blurb]

While waste-to-energy does produce emissions, the EPA concluded that it generates electricity with less environmental impacts than almost any other source.

Marco J. Castaldi: “People don’t make that connection. They don’t see their garbage going hundreds of miles to a landfill and then just sitting in a landfill. And I’m not disparaging the landfill industry. They didn’t make the garbage. You did and I did. They’re managing it for us. So I think if people see the scale and all of this going into a landfill, then they will appreciate [it]. You need systems and technology that can manage it at the scale that we generated at.

The residual stream

Marco J. Castaldi: “All the garbage that we make, not everything burns, not everything is going to gasify, and so on, so you will always have a residual stream. You will always have an ash. And the question then is, what do you do with it? So one black bag that we would throw away would result in maybe about this much ash. So you could send this to the landfill and it’s basically like putting dirt. You’ve extracted almost as much value as you can of everything, and so now instead of sending that last bits that have no value to the landfill, well, maybe it could be put in building materials.”

Anna Naumova (mechanical engineering research associate, City College of New York): “For example, we can use it for pavement. Even for low and for high traffic pavement, which is going to be perfect there. Instead of going in the landfill, we can sell it to construction companies.”

Marco J. Castaldi: “You know in the US, we only do about 12 percent in waste-to-energy, and you know we landfill about 55 to 60 percent. I mean that should be completely reversed, because every ton of garbage that you make energy from, that’s a ton of CO2 offset. That’s a ton of fossil fuel coal that you’re not using. The garbage that you and I throw away is two-thirds biogenic. It’s renewable. So it’s renewable energy. And not only is a renewable energy, but it’s quite steady renewable energy. It’s not like wind or solar.

“We’re going to throw away four pounds per person per day, and we’re going to do that every day. If we have the ability to do a better environmental job and there’s been an established technology that has been demonstrated over 40 years of operation, why won’t you use it, when that has been shown to have lower environmental impact than other options?”