Making fancy fertiliser

"AMERICANS chuck out an enormous amount of food. In 2012, more than 36m tonnes went into the rubbish bin, according to the U.S. Environmental Protection Agency. The vast majority of this ended up in landfills—just five percent was composted. But now two former Microsoft executives think they can make good use of rotting vittles. Their firm, WISErg, has started giving food retailers previously unobtainable insight into their waste by using clever composting machines called Harvesters (pictured above). At the same time, tossed items become fancy fertiliser sold to organic farms.

Understanding precisely why food is thrown out is hard. Store managers know what they order and what they sell, but not what exactly happens to the difference. For instance, did a kilogram of tomatoes go bad and need chucking, or did deli managers add them to a salad that never sold? Typically a supermarket knows how many times a week the dumpsters behind the store are emptied—but they aren't sure why workers toss food or even how full the dumpsters get.

WISErg’s Harvesters generate data on a shop’s food-disposal habits. Seven Whole Foods stores around Seattle have signed up to try one, according to Larry LeSueur, one of the firm’s founders. The company has also "presold" 50 additional Harvesters to a different grocery chain (the name of which it is keeping close to its chest).

Employees will pitch food scraps into these machines after inputting information about exactly which department they work in, what they are throwing out and why. The Harvesters, which can process as much as 1,800kg of food per day, collect additional information including the temperature, the time and the weight of the food scraps. They also take photos. Findings are then sent to a cloud-computing platform for analysis, which generates reports for store managers on rubbish levels and composition. The shops are willing to pay for the machines because they cut waste, and therefore costs, says Mr LeSueur. "

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