Drone-mounted electronic nose used to assess wastewater plant odor
Wastewater treatment plants generally aren't known for their nice smell, and they have to be monitored in order to ensure that they're not becoming too stinky. An experimental new system uses an "e-nose" and a drone to do the job better.
Currently, panels of human participants assess treatment plant odor by smelling bags of air that were captured at the facilities. Not only does this process involve having to go out and manually fill those bags, but it also requires the sniff-testers to be brought together and put to work. Additionally, it's a fairly subjective process, as the ability to discern different odors will vary from person to person.
Led by Prof. Santiago Marco, scientists at Spain's Institute for Bioengineering of Catalonia set about addressing these problems by developing an electronic nose, or "e-nose" for short. The 1.3-kg (2.9-lb) device utilizes an array of gas sensors and artificial-intelligence-based algorithms to detect and measure levels of unpleasant-smelling airborne chemicals such as sulfur dioxide, ammonia and hydrogen sulfide.
Although the e-nose could simply be carried from place to place, the researchers took the additional step of attaching it to a multicopter drone. That drone was then flown over a wastewater treatment plant, where it hovered at various locations and drew air into the e-nose via a dangling 33-ft (10-m) tube.
As a result, the system was able to assess which foul-smelling compounds were being emitted from which parts of the plant, and in what amounts. Its assessments were found to fall closely in line with those of a human panel, who sniff-tested air samples gathered at the same locations. And because the e-nose collected and analyzed samples over a six-month period, it was possible to predict how the plant's odor output may change over time.
"We are extremely happy with the results, but we need more validation and to make the device more robust for a real plant operation," says Marco. "The work may also have implications for other facilities like landfills, composting plants, or even large farms with cattle and pigs that are also known to produce all types of malodors."
A paper on the research was recently published in the journal iScience.