winter 2013/2014
s c i e n c e b u s i n e s s n a t u r e t e c h n o l o g y c u l t u r e p o l i t i c s
breaking it all down for us
B illustration by Otto Steininger; STATISTICS: gwe biogas
by elizabeth royte
Anaerobic digestion enlists microbes to gobble up the organic waste that typically goes into landfills. Could it also turn our rotten melons into fresh megawatts?
neighbors Vermont and Connecticut in requiring that large amounts of organic waste go somewhere other than landfills. (New York City garbage trucks in Massachusetts might smell a little mayor Michael Bloomberg has expressed his wish to enact a similar less putrid than usual, thanks to a new regulation requirement before he leaves office at the beginning of next year.) that would prohibit any generator of more than a Should these regulations have their intended effect, the Northeast ton of food scraps per week from hauling those will likely see a major surge in the technology of scraps to the dump. As the state anaerobic digestion (AD). finally gets serious about divertFor more about waste and reuse, The AD process starts when organic material is ing food waste, it expects to be read Elizabeth Royte’s column at dumped into an enclosed tank and seeded with hunsending much of it elsewhere: to onearth.org/upstreamanddown gry bacteria. As microbes devour this nutrient-rich hungry people, animal-feed producers, commercial material, they produce sugars, fatty acids, and amino acids. Successive composters, and the high-tech contraptions known as anaerobic waves of bacteria then convert these products into carbon dioxide, digesters, which convert waste to energy and fertilizer. hydrogen, ammonia, organic acids, and methane. The biogases With the passage of the new regulation, Massachusetts will join its eginning next summer, landfill-bound
50k
.org
tons of food waste digested anaerobically each year by GWE Biogas, a U.K. facility
2.1
megawatts of energy generated per 50k tons of food waste
3.2k
estimated number of homes that could be powered by 2.1 mW of energy
winter 2013/2014
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