CNN News:美国食物垃圾占供应量40% 新技术将垃圾变为电力

AZUZ: According to the United Nations, food waste is defined as food that's initial safe for people to eat, but it doesn't get eaten because it's left to spoil or it's thrown out. The U.S. government estimates that food waste in America could be as high as 40 percent of the food supply.
But there is a process that ensures that food left to waste doesn't stay that way.
REPORTER: Americans send more than 30 million tons of food to the landfill every year. But as the saying goes, "One person's trash is another's treasure" — really smell treasure.
BOB YOST, A1 ORGANICS, VICE PRESIDENT: We're not dealing with the Bed, Bath and Beyond. These are the smells of nature.
REPORTER: Welcome to Heartland Biogas, a facility in rural Colorado that takes food waste from all over the state and turns it into electricity.
YOST: The waste comes from grocery stores, from cafeterias, from restaurants, packing houses, meat preparation, dog food or pet food manufacturing facilities, food processors, just about any place that has a food-based waste.

REPORTER: The process Heartland uses is called anaerobic digestion, and as the name implies, it works just like our human digestive systems, by breaking down food into energy, in this case, electricity.
The food waste that comes into the facility is separated from any packaging, chewed up into a more digestible state, and mixed with bacteria, in one of Heartland's 1.7 million gallon holding tanks. And while in human digestion, gas is far from being the goal. Gas is exactly what Heartland is after.
Remember the smell from before? It's methane and it's a great source of renewable energy.
YOST: We create three things: gas, liquid soil amendment, and solid soil amendment of peat moss like material.
The digester is just like your stomach's bacteria. The bacteria eat the organics and then they create gas. Not unlike what we do.
REPORTER: Methane is a powerful greenhouse gas. So, when food rots in a landfill and sends gas into the atmosphere, it's bad news for the environment. In fact, if global food waste were a country, it would be the world's third largest emitter of greenhouse gases. The methane made in Heartland's digesters is pumped into an interstate pipeline where it can be accessed as a source of clean renewable power, all while cutting on harmful emissions.
YOST: The vast majority of the materials that we processed were originally landfill or disposed of. We can process up to 1,200 tons a day. That's really good size landfill. If you're doing 240,000 tons a year into a landfill, that's a lot of waste. This is a very efficient and impactful way to be capturing that resource.