Why an MIT robot is collecting poop from our sewers

Luigi's job is to gather what we flush so that researchers can learn about our habits and our health

January 19, 2017
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by Cynthia Graber

Newsha Gaeli didn’t come to MIT to study sewage, but on a chilly November morning, she’s staring into an uncovered manhole near campus, watching water churn below her colleague Luigi as Luigi is raised from the sewer by another MIT researcher, Shinkyu Park. Ghaeli and Park occasionally wince as the scent of rotten eggs penetrates their protective masks. “This is worse than anywhere we’ve ever sampled,” Ghaeli says. Luigi doesn’t notice — Luigi is a robot.

On-board sensors tell Luigi — a plastic-encased tubular tangle of wires, batteries, and electronics — when it’s below the waterline, the water temperature, whether the water is flowing, and how much is in the 250-milliliter bottle (about 8.5 fluid ounces) it carries. The bottle is sterile and empty when Luigi is lowered on 60-pound fishing wire the 10 feet or so into the sewage stream. But when Luigi returns, the bottle is filled with a gray-brown liquid, a broth of flushes and drains from neighboring homes and businesses. And it is covered with clumps of an unwanted substance: toilet paper.

Ghaeli grimaces. “There’s a lot of toilet paper here,” she says as she gingerly wipes away the wet muck from the bottom of the robot. Toilet paper is enough of a problem that Ghaeli and Park’s research team, dubbed “Underworlds,” built a fake flowing toilet to help determine which kind of mesh cover would best keep it from gumming up Luigi’s works, but still let in tiny bits of solid fecal matter for useful data. “We’ve designed multiple versions,” says Ghaeli. “The one we have currently works nine times out of ten.”

Read the full story via The Boston Globe