Americans generate more than 250 million tons of trash every year, which amounts to more than 1,600 pounds per person annually. We recycle or compost just over a third of it. Most of the rest goes to landfills, with all their environmental problems. What are alternatives to landfills?
Basically, we can either bury it or burn it. Nowadays, burning it means using waste-to-energy (WTE) technology.
It has been remarkably difficult to find any useful data about the history of waste incineration in the US. The first incinerator began operation in 1885 in New York City. Since then, I gather, incinerators have gone in and out of fashion. They appear to have worked less well and less economically than anticipated.
The Clean Air Act of 1970 forced existing incinerators either to undergo expensive upgrades or cease operation. EPA rules regarding emissions of mercury and dioxins in the 1990s had the same effect.
The first incinerators were not WTE plants, but most waste incinerators produced electricity by the early 1990s.
According to the EPA, burning garbage releases more carbon dioxide (CO2) than burning coal. But most of it is biomass. It releases both CO2 and methane in landfills. That is, if burning it doesn’t release greenhouse gasses, landfilling it will. Burning fossil fuels releases less CO2 and no methane. On the other hand, it does not help manage solid waste.
But the EPA further warns that burning municipal solid waste produces nitrogen oxide, sulfur dioxide, dioxins, mercury compounds, and other toxins.
Opponents of waste incineration have successfully played the NIMBY card. No one wants to live near a power plant. No one wants to live near a landfill, either. What’s more, so many incinerators, landfills, hazardous materials processors, etc. are located in impoverished areas that they raise questions of environmental racism.
WTE technology in the US
In 2015, a WTE plant built in West Palm Beach, Florida became the first new one constructed in the US in 20 years. A plant proposed for Baltimore was running into stiff opposition. The ZIP code where it was proposed to be built already had some of the worst air pollution from toxic emissions in the country.
Baltimore also had the highest emissions-related mortality rate in the country. And the proposed facility would have been permitted to add 240 pounds of mercury and 1,000 pounds of lead to Baltimore’s air every year. It was never built.
But Wheelabrator operates a WTE facility in Baltimore built in 1985. The largest contributor to the city’s air pollution, it emits tons of toxins into the air. Yet in 2011, it helped write state legislation that qualifies WTE facilities to receive subsidies intended to promote renewable energy. Fewer than a dozen states consider WTE as a “green” technology deserving of subsidies.
Wheelabrator points out that it meets or exceeds hundreds of air quality standards. Yet it emits 64% of the nitrogen oxides from Baltimore’s smokestacks and 82% of the city’s sulfur dioxide. A similar plant in Montgomery County emits less than half the amount of nitrogen oxides.
Elsewhere, installation of expensive WTE plants helped push other cities, including Camden, New Jersey, Detroit, Michigan, and Harrisburg, Pennsylvania toward insolvency. As of April 2017, 86 WTE facilities operated in 25 states, mainly along the east coast.
WTE technology in Sweden
WTE technology isn’t controversial everywhere. Sweden relies on it.
Sweden sends less than 1% of its trash to landfills. Instead, its 32 WTE incinerators burn trash to produce steam that runs turbines at electric plants. Swedes also recycle about half of their household waste. Swedish law makes the process of reuse, reduce, recycle more efficient than anywhere else in the world.
Its success at recycling coupled with its reliance on WTE results in a trash shortage. Sweden must actually import trash from other European countries that lack its recycling infrastructure in order to have enough to produce its electricity.
Filters and scrubbers at WTE plants clean the emissions, so the plants produce little air pollution. They do emit high levels of carbon dioxide.
Three key differences between Sweden and the US explain the acceptance and success of incineration there:
- Swedes produce less trash: just over 1,000 pounds per person annually, compared with more than 1,600 pounds in the US.
- Swedes recycle much more of their waste than do Americans. Apparently, they remove all valuable metals and plastics from the waste stream before they reach the incinerators.
- Swedish law imposes much more stringent air-quality standards on its incinerators than does US law.
It appears that, in the US, WTE technology is losing ground both to natural gas and such renewables as wind and solar. None of these energy sources deal with solid waste. The author of the Slate article in the list of sources suggests trying to sell WTE as a Swedish innovation. He even advocates adopting the Swedish word, förbränning, for incineration. It sounds better.
Less facetiously, it appears that WTE would make a better case by comparing itself to greenhouse gasses from landfills rather than to other methods of generating electricity. And submitting to regulations as stringent as those in Sweden.
WTE technology beyond incineration
Conventional WTE incineration relies on ordinary combustion, much like a fireplace or camp fire. The fuel burns with oxygen at a few hundred degrees. The process releases various gases and lots of heat. It leaves behind ash. Incomplete combustion produces dioxins. If the fuel contains any heavy metals, they remain in the ash.
So unlike an ordinary fire, WTE incineration requires combustion in a closed container. The incinerator operates at a higher temperature than most fires in order to destroy as many toxins as possible. It has a very tall smokestack, with scrubbers to trap particulate matter. The plant captures the heat generated by burning the waste and uses it to boil water to drive a steam turbine and generate electricity.
Environmentalists often exaggerate the toxicity of coal ash. Ash from incinerators, which burn batteries, electronic waste, and toxic chemicals, is more hazardous.
Pyrolysis works on plastics and biomass by subjecting it to high heat in absence of oxygen. The lack of oxygen prevents combustion. Not all plastics are suitable for pyrolysis, however.
PVC (no. 3 in the recycling triangle) produces chlorine when heated, and the chlorine corrodes the reactor. PET (no. 1), releases oxygen into the chamber, which, at best, slows the reaction time. PET, however, is easily recoverable from mixed plastic and valuable as a raw material for many products.
The heat in a pyrolysis reactor breaks long plastic molecules into shorter ones. Pyrolysis produces coke, synthetic gas, and a liquid oil that can be used all the same ways as crude oil. It reduces the volume of the waste by 50-90%.
Pyrolysis is a proven technology, known as both sustainable and profitable.
Plasma arc technology
Plasma arc recycling heats the waste to thousands of degrees instead of hundreds. It vaporizes the waste. When it cools, only gasses remain of organic waste, mostly carbon monoxide and hydrogen. Inorganic waste, including heavy metals, cools back to chunks of glass-like solids.
The heat from a plasma arc waste plant can operate a steam generator. The carbon monoxide can be burned like natural gas. The hydrogen can be collected and used for fuel cells. The glass-like solid residue makes a suitable aggregate for construction and roadbuilding.
In principle, therefore, plasma arc technology produces no air pollution, ash or dust. The vitrified aggregate traps heavy metals so they won’t leach out into the environment.
The human race has a long history of embracing new technology and learning of the hazards only later. Plasma arc technology is so recent that any drawbacks haven’t had time to show up yet. We don’t know that toxins can never leach from the aggregate. But we do know that dioxins remain in the gas. No one knows if plasma arc technology is economical, either.
Look for plasma arc technology to become more common and hope someone is watching the outcomes very carefully.
Three WTE technologies, therefore––incineration (subject to regulation comparable to that used in Sweden), pyrolysis, and most likely plasma arc technology––appear to provide viable alternatives to landfills. We should quit bickering and learn to use them effectively.
Energy recovery from the combustion of municipal solid waste (MSW) / US EPA
Förbränning for all! The sensible Swedes burn a lot of their garbage. Why can’t we? / Daniel Gross, Slate. July 21, 2014
Garbage incinerators make comeback, kindling both garbage and debate / Timothy Williams, New York Times. January 10, 2015
Plasma arc recycling / Chris Woodford, Explain That Stuff! February 20, 2017
Power struggle: How a trash incinerator — Baltimore’s biggest polluter — became ‘green’ energy / Scott Dance, Baltimore Sun. December 15, 2017
Sweden’s strange problem: not enough trash / Lauren Murphy, Earth 911. January 3, 2017
Capped landfill. Public domain from Wikimedia Commons
Incinerator combustion. Public domain from Wikimedia Commons
Swedish WTE plant. Public domain from Wikimedia Commons
Pyrolysis. Source unknown