The growing popularity of modern waste-to-energy (WTE) facilities in Europe and Asia has many in America asking: is burning trash bad?
We're not big burners here in the U.S., but we've been known to light up some litter from time to time. The majority of our waste is buried in landfills, while 31 percent is recycled, but there are currently 90 waste-to-energy facilities operating in the country that torch 14 percent of our trash and convert the heat into electricity.
John Norton, engineering consultant and owner of Norton Engineering LLC, ran a now-defunct WTE plant in Dayton, Ohio for over a decade, and he is familiar with the internal goings-on of waste-to-energy and the misconceptions that often surround the facilities.
“Sometimes people would ask me if the plant was running,” Norton remembers. “When I asked them why, they said ‘because there’s no smoke!’”
“If you see smoke, you can bet that those operating the plant are running around like rats trying to fix something,” he says. “If there is visible smoke of any sort, we have a big problem. The EPA monitors all of the stack emissions all of the time. There’s just no cheating possible.”
Engineers like Norton advocate the cleanliness and safety of WTE facilities and are puzzled why an energy source as renewable as trash has not been explored further here in the states, but many environmental activists are pleased with American skepticism about waste-to-energy.
“There are incinerators in Japan and Europe that are newer than the ones in the U.S. because communities are so successful in questioning the approach of burning all of those resources,” says Monica Wilson, director of the Global Alliance for Incinerator Alternatives (GAIA).
In this hot-button debate, activists like Wilson remain unconvinced that waste-to-energy facilities are free of the hazardous fly ash, human health concerns and environmental impact of their predecessors.
So, how do these plants work, and are they really safe? Could garbage really be the renewable energy solution of the future, or is big-business pulling the wool over our eyes with a fancy new name and a "greener" business model?
The experts weigh in
The EPA points out that “combusting municipal solid waste has a negative public perception in some communities,” and while many are quick to point out the draw-backs of waste-to-energy disposal, there are plenty of voices speaking out on both sides of the issue.
“We all picture a burning 55 gallon barrel in somebody’s back yard, but that’s not what we’re talking about,” says Norton. “We’re talking about very clean combustion under very controlled conditions.”
But emissions are not the only concern for environmental activists like Monica Wilson. Financial burdens and the possible impediment to recycling expansion are also big problems.
“There are so many economic reasons for local governments to look into expanding their recycling programs,” says Wilson. “Recycling programs create local jobs and feed materials back into local, regional and national industry [...] That’s a really important thing to be thinking about instead of spending millions and potentially up to a billion dollars on a new facility."
“It is important to talk about zero-waste in local government and to adopt zero-waste as a goal,” Wilson says. “It doesn’t mean we’re going to be at zero-waste tomorrow, but the only way to reach that goal is to set it.”
“There is a lot that communities can do in the short-term that will have a huge impact,” she adds. “I think we can achieve a lot and a lot faster than the waste industry would say, because their profits come from wasting as much as possible.”
Others argue that with waste constantly streaming in, WTE facilities should be explored as a cleaner alternative to landfills.
“If I had a primary goal, I would not call it zero-waste,” says Norton. “I’d call it zero-landfill.”
The environmental bottom-line
The strict standards of the Clean Air Act significantly reduce the environmental impact of waste-to-energy facilities by controlling the emissions of hazardous organics including dioxins and furans, hazardous metals and acid gases.
A variety of processes are put in place to ensure the clean operation of a WTE plant, including “dry scrubbers,” which use the old gardener’s trick of spraying lime to neutralize acids and electrostatic precipitators, a fancy term for electrically charged plates that capture small particles and fly ash in the same way your TV screen attracts dust.
Federal standards are also imposed on landfills, which must be designed “to protect the environment from contaminants which may be present in the solid waste stream,” says a spokesperson for the EPA.
To comply with these standards, landfills must be methodically constructed to avoid groundwater and environmental contamination. Although both WTE plants and landfills are subject to stringent EPA standards, neither are free of potential environmental and public health problems.
“Emissions of hazardous air pollutants from waste-to-energy combustors and fossil fuel boilers can be controlled to trace levels,” explains the EPA. "However, environmentalists express concerns about these residual emissions.”
Activists such as Monica Wilson point out that residual emission from both landfills and WTE facilities pose a potential threat to public health and may still contain gases harmful to the environment.
“Landfills generate methane, which is a very potent greenhouse gas,” says Wilson. “When you throw waste into an incinerator, no matter how clean it claims to be, greenhouse gases are still produced and so are other potentially harmful emissions.”
The concerns of environmental activists like Wilson are warranted. Both landfills and WTE facilities do emit greenhouse gases.
However, when you compare the two, there is a difference.
According to a report by P. Ozge Kaplan, Joseph DeCarolis and Susan Thornloe, “Burning one ton of waste in a waste-to-energy unit saves between 0.5 and one ton of greenhouse gas emissions compared to landfilling the same amount of waste.”
How recycling fits into the equation
When a WTE facility is constructed contracts are formed between the company operating the facility and the municipality, which mandate the flow of trash into the facility.
From a business standpoint, this means that the operating company and the municipality are shelling out millions to construct the plant. So, they want to make sure enough electricity will be produced to make it worth their while.
The EPA admits that “WTE facilities may be an impediment to further waste reduction, reuse and recycling given that the economic viability of the WTE facility is based on a given supply of wastes.”
For this reason many environmental activists like Wilson express concern that WTE plants may prove to be a disincentive to recycling, composting and reuse.
“If a community has a facility that must receive a certain amount of tons per day, they can’t build a recycling program that’s bigger than that,” says Wilson. “Often times the amount of waste that is required to go into the incinerator cancels out a community’s recycling goals. It’s simply not possible to recycle what the community wants to recycle and still feed the incinerator enough waste per day.”
But according to Norton, most waste-to-energy plants don't need your recyclables to meet their bottom-line.
“When you take all bottles, cans and paper out of a load of waste and study what’s left, the combustion characteristics haven’t changed at all,” Norton says. “Recycling programs are no threat to a waste-to-energy plant. When one of these plants is proposed you often find that the plant itself becomes the agency that encourages recycling.”
A 2009 study conducted by Eileen Brettler Berenyi examined the recycling rates of more than 500 communities with waste-to-energy facilities and seems to prove Norton’s theory. The findings of this study were that communities with waste-to-energy facilities had a higher recycling rate than the national average.
Recycling also takes place within the plants themselves. After residual ash cools, magnets and other devices remove metal scrap. These scraps of metal, usually iron and steel, can be as small as paper clips and staples, but add up to thousands of tons over time.
Why burn trash in the first place?
The average American tosses 1,600 pounds of trash per year, which is enough to take up two cubic yards of landfill space.
At that rate, our purple mountain majesties could turn into an Appalachian Trail of trash. So, it's no wonder that facilities that can decrease the volume of waste and provide renewable energy are so attractive to the U.S. government.
After being burned in an incinerator, residual ash is only about 15 percent of the original load of waste. Translation: after incineration your 1,600 pounds of trash becomes 240 pounds of ash, which is much more manageable for waste management workers.
Some incineration facilities, called solid waste incinerators, only exist to serve this purpose. They don't produce electricity. They only burn your trash to make it smaller, easier to dispose of and less space-consuming in landfills.
On the other hand, waste-to-energy facilities shrink trash and use the heat to produce steam and electricity. These facilities have the added benefit of producing energy from material that would otherwise be landfilled.
U.S. WTE plants dispose of the waste of 40 million people and generate enough electricity for nearly 3 million households.
What about that ash?
The amount of residual ash varies depending on the waste being used. It usually represents between 15 and 20 percent of the original load of waste, which sounds great. Less landfills the size of Mount Everest, right?
Right, but there's a catch. Disposing of ash can be problematic, and the issue of residual fly ash is huge with environmental activists.
Ash can contain high concentrations of various metals once present in the original waste. For example, printer inks and textile dyes can release iron and cadmium into the residual ash.
Sorting trash before incineration significantly reduces this problem. The major culprits of metal residue are batteries and paints. Removing these materials before loading the boilers reduces metal concentration in the ash.
Don't worry, the EPA isn't simply taking a plant-owner's word for it. They test the ash from WTE plants to make sure it is safe. Tests are generally looking for chemicals and metals that may contaminate groundwater if placed in a landfill, and once ash is pronounced safe, it is landfilled or used for a number of applications.
About one-third of all the ash produced by WTE facilities is reused in landfills as a daily or final cover-layer or to build roads and make cement.
The final verdict
According to the EPA, “The decision to build a waste-to-energy facility depends on many factors, including geography and population density, the willingness of citizens to accept the technology, the willingness of investors to support it, and on state and local officials who determine how solid waste is handled in a particular area of the country.”
While environmental activists and the waste management industry disagree about whether the U.S. should burn or bury its trash, all agree that recycling is still the No. 1 disposal option.
The EPA promotes a waste reduction hierarchy that encourages reducing waste at its source, then recycling. Recycling is preferable to waste-to-energy and landfilling for materials.
The waste-to-energy debate will likely rage on, America, but at least we’re all on the same page in our knowledge that the chasing arrows are still our best disposal bet.
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