The city of Minneapolis is experimenting with a unique method for detecting problem areas in its collections system — drones.

This fall, when the city conducts its annual smoke testing, drones will be circling the skies getting images of hard-to-access rooftop vents. Katrina Kessler, the city’s director of surface water and sewers, told the Minneapolis Star-Tribune that 99 percent of the city’s sanitary and stormwater sewers are separated and the search for any leftover connections — accomplished through the annual smoke testing — is about three-quarters of the way done. Pumping smoke into the sanitary system then watching it come out of exhaust vents (versus a curbside storm sewer) is a good sign that all is well. That’s straightforward in residential areas where the rooftop vents are easy to spot from the ground, but it’s a much more difficult task in areas with large apartment buildings or other large industrial structures.

“In order to actually see if it’s working, you have to get up on the roof to see,” Kessler told the Minneapolis Star-Tribune. “And that involves a lot of coordination, and it also can be a safety risk because often those areas are not meant for human habitation.”

The drones will provide that rooftop view instead, and crews can examine the photographs later for signs of smoke.

“We can actually track how long it takes us to do the work and whether or not we’re more efficient,” Kessler says. “This could inform other uses going forward.”

Source: Minneapolis Star-Tribune