What lies beneath ... 'Smart Sewage' could spot epidemics before they happen

A city's sewers could hold the secrets of its residents' health.

Story highlights

  • "Underworlds" project will analyze sewage to spot diseases
  • Monitoring city sewage could reveal infections circulating in the population
  • The project could one day be applied to create individual "smart toilets"
Valuable insight into our health is lurking beneath our city streets. "We can reveal the invisible in a city. The underworld we don't see every day," says architect Carlo Ratti.
The underworld Ratti is referring to is our sewers -- home to the most personalized waste a city has to offer. As director of the Senseable City Lab at MIT, his "Underworlds" project is using this waste to open up a new world of information on human health and behavior through a platform he calls "Smart Sewage."
"New techniques in biology allow us to characterize bacteria and viruses leaving our bodies. [This is] the microbiome of us," explains Ratti. His team is currently designing prototype smart platforms that collect sewage, filter it and use computational techniques to analyze any genetic material present to identify any viruses and bacteria, as well as spotting specific chemicals using a technique known as mass spectrometry.
Ratti aims to characterize a city's microbiome (the vast community of microbes that lives in the human body) and ultimately "see epidemics before they happen."
Detecting infections
The main benefits lie in the real-time aspect of the technology, providing insight into the diseases circulating in a community before the people affected know for themselves. "The steps involved in disease diagnosis are slow," Ratti explains. First, people need to notice symptoms of illness, and then they have to begin the process of doctors' appointments and tests to get a diagnosis. Testing sewage could be a faster way to predict the presence of infections among the population.
To begin with, the project will primarily look for influenza and gastroenteritis-related outbreaks, such as salmonella and rotavirus infections, but the potential public health benefits go beyond outbreak prediction and surveillance.
"Most of what's going in and out of a city is the water going in and sewage coming out," says Eric Alm, professor of Biological Engineering and Civil and Environmental Engineering at MIT, who runs the Underworlds project alongside Ratti. "The change in water in and out reflects a broad array of human activity going on in a city," he adds. But Alm admits there are many challenges ahead and that it's not as straightforward as getting DNA from the sewage and sequencing it. "It's only useful if we can figure out what kind of sewage water it is," he says.
The water in our sewers is a mix of water from showers, toilets and rain, and the resulting chemicals and microorganisms will vary depending on the source. "The second challenge is, who has contributed to that water?" explains Alm.
But he believes his team can build a robust platform to not only monitor changes in health, but also see what chemicals are being released into the water by industries, a