MIT Senseable City Lab

Urban sewers are rich repositories of information on human health and behavior, MIT researchers believe.

Show some love for your sewer system. Besides seamlessly handling your waste (most of the time), sewers fight disease. Cholera, typhoid, dysentery, and many other fatal infections that once spread rampantly via poor sanitation no longer plague cities of the developed world, thanks to underground pipes and treatment plants.

We’ve been enjoying these luxuries long enough to forget that they’re luxuries. Now, at the cusp of the “smart city” era, our underground networks are beginning to take on new duties as servants to public health.

“You can tell a lot about a person by sampling their microbiome: presence of illness, certain genetic tendencies, and overall health,” says Carlo Ratti, architect, engineer, and director of MIT’s Senseable City Lab. Those invaluable biomarkers live on in our sewage, which is why Ratti has been decoding microbes in the sewers of Cambridge, Massachusetts, for more than a year, alongside MIT computational microbiologist Eric Alm, other researchers, and city officials.

The pilot project has sometimes been messy; at first, researchers shimmied down manholes to manually collect waste. Known as Underworlds, the initiative now involves a network of automated robotic samplers stationed throughout the city in residential neighborhoods, industrial areas, and at Harvard and MIT. In almost real time, the robots relay data back to MIT, where Ratti and Alm’s labs decode it for biochemical information and visualize it online.

There are still kinks to be worked out, but so far, the results are impressive. A single sample of sewage, for example, has been found to contain more than 58,000 viruses, many of which are hosted by bacteria associated with gastroenteritis, skin warts, and the common flu.

Collected at a large scale and with fine space-time resolution, this information could be used to predict outbreaks of infectious disease and to note the presence of new viral strains. Think about how useful this could be for something as common as the flu: “[It] could significantly reduce a community’s medical costs, save lives and help prevent pandemics,” Ratti says.

The Underworlds platform could also be used to chart new kinds of demographic information. For example, neighborhoods with more antibiotics in their wastewater might have larger populations of children or elderly people, or higher rates of health care access. Data like that could lead to a new type of population census (it’s worth noting that stuff in sewage samples can rarely be traced back to individual sources).

Underworlds is a “proof of concept” project—it’ll take more investment and scale to see its full potential. Right now, operations are expanding to Kuwait, where Ratti says the platform’s ability to detect enterovirus outbreaks will be of particular interest.

In Cambridge, the robots will continue to sample and analyze waste through 2017. Who knows what else they’ll turn up? Besides gallons of information on human health, perhaps they’ll help the city find sources of industrial chemicals, or even leaky pipes—a major problem across America’s aging wastewater systems.

Sewers, we love you, but it’s time for a upgrade. Underworlds may point the way.

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