New York City is an island built on garbage. Dutch settlers constructed much of the southern tip of Manhattan by extending the shoreline with landfill. But today, waste management is a major issue--and we’re running out of room. New Yorkers generate at least 10,000 tons of solid waste per day, much of which is hauled out of the city by greenhouse gas puffing biodiesel trucks. It’s not exactly cost effective either, at $300 million spent on this export process annually. That’s why, as part of the city’s effort to double the amount of waste diverted from landfill, Mayor Bloomberg called for proposals earlier in the week for a “state of the art conversion technology facility” that didn’t feature mass trash incineration. So, what does “conversion technology” even mean? Here’s a list of 10 ways, some real and some imaginary, one might convert waste to energy, from oil rendered from denatured turkey guts to Back to the Future’s Mr. Fusion.
1) Anaerobic digestion
While burning municipal solid waste may be the most popular way of converting garbage to energy, it's certainly not the best idea for air quality. Anaerobic digestion breaks down garbage into fuel by making our bacteria friends do the dirty work for us. The result of this process is sludge (sometimes used as fertilizer), as well as a biogas combo of methane and carbon dioxide that can then be used to produce electricity and heat. As with most other progressive things, like eating normal-sized meals and providing healthcare to its citizens, Europe is way ahead of the game on this one, as Germany, the UK, Denmark, Spain and France already have successful anaerobic digester programs in place.
Also known as "plasma arc waste disposal," gasification is the process by which trash is zapped and vaporized at 10,000 degrees Fahrenheit in a "plasma converter" to produce a synthetic gas ("syngas" if you're hip to the eco-lingo), which powers a turbine and creates steam to produce electricity. It's kind of like a big, complex microwave with superpowers. A really big, complex microwave with superpowers.
3) Thermal Hydrolysis
Garbage gets boiled to generate a biogas, then used to produce electricity. The good news about thermal hydrolysis is that it rids the sludge of pathogens in the process, and it's often used as a precursor to anaerobic digestion.
4) Mr. Fusion Home Energy Reactor from Back To The Future III
Doc made a serious, environmentally conscious upgrade when he decided to power his time-traveling DeLorean with garbage instead of stolen plutonium from the Libyans. The only logistical problem with this is that Mr. Fusion's 1.21 gigawatts "only powers the time circuits and the flux capacitor, but the internal combustion engine runs on ordinary gasoline." Well, fuck. There goes our energy independence.
We've had this technology around forever--we've just been using it to get drunk. Fermentation of biomass waste (biological matter from plants/plant material) to create ethanol is the same process by which we make wine, where sugar is converted to carbon dioxide and alcohol.
6) Thermal Depolymerization or Thermal Conversion
Thermal Depolymerization (sheesh, that's a mouthful) or TDP works the same way that natural, geological processes do over millions of years, by breaking down organic waste into oil--only TDP does it in hours. Plants in Philadelphia and Missouri have already used TDP near turkey factories to break down turkey guts into fuel. Gross.
Another kind of thermal technology, pyrolysis heats up trash in an oxygen-depleted environment to decompose waste and produce a gas that can be used as fuel.
8) Garbage Powered Cars
Huddersfield, in the UK, was one of the first locales to have its own garbage-powered garbage truck. The retrofitted Ford Transit was powered by a lithium-ion battery pack that was charged at the town's Energy From Waste Center.
9) Robots With Artificial Guts
Two years ago, a robotics lab created the Ecobot-III Bio-Regulation and Energy Autonomy with Digeston (or BREADbot). The BREADbot featured an artificial stomach that included decomposer bacteria in something called a 'microbial fuel cell.' Every 24 hours, the BREADbot crapped out carbon dioxide and liquid waste, while the microbial fuel cell created enough energy to power the bot itself. It's not too efficient unless you have an army of these guys, but the idea is pretty cool.
10) Monsters With Imaginary Guts
New York natives Ickis, Oblina and Krumm from the old Nickelodeon show Ahh! Real Monsters lived on the scrumptious garbage they found at what was presumed to be Fresh Kills Landfill. Time to track down these little buggers and give them city jobs.