What happens to the tons of plastic bottles, aluminum cans and cardboard boxes residents of the Birmingham suburbs leave on their curbs each week?

It’s a burning question for those who care about what happens to the recyclables after the waste hauler picks them up.

While many may believe their waste is eventually reborn in another life as new plastic bottles or Amazon delivery boxes, some of it instead may be going up in smoke.

How? In a process that turns the material into “energy feedstock” to be burned as fuel, local officials say.

Glen Adams, the interim city manager in Homewood, said the production of energy feedstock diverts trash away from landfills. “But it doesn’t do what everybody considers true recycling.”

In the suburbs, the trash and recycling are “commingled” in one collection that’s picked up by AmWaste, the private company that contracts with the cities for waste pickup. A spokesperson for AmWaste said the company sometimes takes the commingled collection to Big Sky Environmental, a landfill north of Birmingham. Big Sky determines what is recyclable, and the “highest and best use to do so,” said David Mowery, spokesperson for AmWaste.

The larger items from the commingled collection are sorted out, Mowery said. Then, a combination of solid waste and recyclables are taken to VLS Environmental, an industrial waste provider in Bibb County. VLS turns those items into “energy feedstock.”

Big Sky and VLS did not respond to repeated requests for comment. VLS Environmental advertises on its website its ability to create “alternative engineered fuel” at its Alabama location.

But the “energy feedstock” practice raises questions among environmentalists, and the issue is causing the state to update its recycling rules.

What is ‘energy feedstock?’

Adams in Homewood described the process as cleaning and pulverizing waste, which is then burned as a fuel source.

According to the city of Vestavia Hills, the energy feedstock is used as a fuel source in cement production facilities. The energy feedstock burns “cleaner than coal,” the city claims on its website.

But not everyone is sure it’s the best method for diverting trash from landfills.

Shenghua Wu, a professor at the University of South Alabama and director of the school’s Solid Waste Sustainability Hub, said energy recovery is ideally a “last resort” for waste management.

“This method involves combusting materials such as plastics, paper, and biomass-based recyclables to generate electricity or heat,” Wu said. “While this practice offers potential benefits, it also presents significant challenges and environmental trade-offs.”

In addition to air quality concerns, waste-to-energy also takes recyclables out of use. Some plastics are very recyclable, Wu said, but not if they are burned for fuel or disposed in a landfill.

“Waste-to-energy systems may offer short-term relief by reducing landfill pressure, but without robust emission controls, incentives for material recovery, and public transparency, they risk undermining long-term goals such as zero waste and a circular economy,” Wu said in an email. “Ideally, energy recovery should serve as a last resort, implemented only after all options for waste reduction, reuse, and recycling have been exhausted.”

Last month, AL.com reported that recyclables tracked from Homewood, Vestavia Hills and other suburbs went to Big Sky Environmental, a large landfill northwest of the city, instead of RePower South, a recycling facility in Montgomery.

Normally, the “commingled” collection is supposed to go to RePower South, which has a machine that is supposed to be capable of sorting trash from recycling. Some hard-to-recycle paper and plastics are converted to fuel at RePower South, too.

But when RePower South is closed, AmWaste previously told AL.com they bring the commingled collection to Big Sky, and some of it then goes to VLS Environmental.

Both Big Sky and VLS Environmental have state permits to recycle, but specific permission to convert recyclables to fuel is not required. That’s according to an official from the Alabama Department of Environmental Management.

Kate Cosnahan, board president for the Alabama Environmental Council, said she doesn’t know much about Big Sky’s recycling capabilities. The council frequently received questions from Birmingham metro residents about where their recycling was going, and she and others at the nonprofit researched the topic and didn’t get many answers. She said she has a lot of questions about the “energy feedstock” method.

“I don’t know what kind of fuel they’re capturing, where is the exhaust going, what’s the air quality like around the area?” said Cosnahan, an environmental scientist. “I just don’t know.”

Recycling in the suburbs

AmWaste said the “energy feedstock” method meets the requirements of its contract with the cities.

“It is an approved method of recycling under Alabama law, and it satisfies AmWaste’s obligation to the authority,” Mowery said in an email.

Lynn Battle, a spokesperson for the state’s Department of Environmental Management, said that using recycled materials as fuel is not considered recycling in Alabama.

“In accordance with ADEM Administrative Code … recycling does not include the use of materials as a fuel,” Battle stated in an email. “However, converting recyclable material into a fuel source is considered diversion from the solid waste stream and is an allowable activity by properly registered facilities.”

Still, ADEM is looking closer at the practice.

“The department is currently updating its regulations to include reporting on the utilization of solid waste materials as fuel and to improve the reporting of recycling activities in Alabama,” Battle stated in the email to AL.com.

Waste haulers like AmWaste are not a direct part of this recycling process.

Once the private company drops off the commingled collection, it’s out of AmWaste’s hands, Mowery said.

“What happens at RePower, Big Sky, [Birmingham Recycling and Recovery] or any number of facilities across our footprint is the concern of that company,” Mowery said. “Unless there are state issues with ADEM or other permitting authorities, we will assume these companies perform the duties they say they will, just as we do for them.”

Under the Birmingham suburbs’ contract with AmWaste, the commingled collection must be sent to a facility capable of sorting recycling from the trash and “reducing placement in the landfill.”

In Vestavia Hills, city officials say AmWaste’s program is less expensive and more efficient than the previous way of recycling.

City Manager Jeff Downes recently told the city council that he estimates 2,933 tons of waste from the city is diverted from the landfill under the AmWaste system each year.

Under the old system, the city paid more than $1 million per year for a recycling-only pickup each week, Downes said. And the city’s “effective tonnage,” or the amount of recycling that was actually recycled, was 1,700 tons in the last year of the old system.

“So, more effective if you’re looking at diversion from landfills, not necessarily if you’re a purist and want commodities to be resold,” Downes said during the meeting. “But diversion from landfill, it’s effectively doing what we said it’s going to do.”

Beyond how plastics, cardboard, and cans are “recycled,” city officials in Homewood expressed frustration at what they said was a lack of communication about where recycling from the Birmingham suburbs is going.

Councilman Nick Sims said he, like a lot of other Homewood residents, solely uses the “commingled” collection. He reserves all of his trash for that pickup each week, instead of using the “trash only” pickup, in the hopes that as much will be recycled as possible.

“The lack of communication not only is bad for AmWaste, it’s bad on the city now, because we’re the ones who actually are responsible for providing the service to the residents,” said Sims. “It’s the resident’s taxpayer dollars that they’re paying for this service, and if we’re not providing what we’re saying we are, then that’s a serious problem.”

Ultimately, though, the cities are still sticking with AmWaste for the time being. Adams said AmWaste was trying to “meet the intent” of their contract.

“[AmWaste] just didn’t understand how they need to be communicating,” Adams said. “We could have gotten very adversarial and gone a different route…I don’t particularly want to go that route unless the rest of the cities are wanting to do that. And right now, I don’t know that they are.”