Currently, pipelines are inspected using “smart pig” technology, which uses an electronic sensor that travels through the pipe detecting cracks or welding defects. Despite regular such inspection using this approach, leaks still occur.
Now researchers say they are developing a biosensor that would complement this process by providing additional information about the integrity of the pipes. The sensor adheres to the outside of the pipe, and takes advantage of the metabolic process of bacteria to detect gas leaks in real time.
“The advantage with our sensor is that it can detect very small leaks, and operators can take quick action to repair them,” says Veera Gnaneswar Gude, Ph.D., and leader of the project. “We no longer have to wait until the leak is out of hand. Plus if we are able to develop this system on a larger scale, the same unit would be able to treat the waste and to remediate the soil and water that has been contaminated.”
The new biosensor technology uses an “electrogenic” bacteria that releases electrons to its environment through metabolic processes. Gude is currently testing bacteria that will elicit an adequately measurable cathode voltage while also being able to survive in a marine environment for the application of offshore oil spill detection. For this to work, the bacteria have to remain robust through a range of alkalinity, pressure and pH conditions.
An organic sensor was created comprising an electrogenic anode made up of bacteria that consume carbon-based material – gas or oil – and expel electrons, which then travel across a resistor to a cathode. A different set of bacteria – which are “hungry” for electrons – resides at the cathode encouraging electron flow. An increase in the metabolic processes of the anode bacteria will correspond to a voltage increase in the sensor – alerting a technician to a potential leak.
“The sensor is not difficult to implement,” says Gude. “Placing the sensor onto a pipe is not a big challenge. It is a very versatile technique.”
Currently, the researchers are looking for a medium in which to immobilize the bacteria. Possible candidates include high-porosity plastics and bio-based films that optimize the surface area that the electrogenic bacteria can cover.
Once rugged bacteria are identified and immobilized, they can be used as leak detectors in a range of oil transport and drilling applications, including fracking. In the future, say the researchers, it is possible that the sensor could be sprayed as a coating on the exterior of pipes enabling the entire length to be continuously monitored.
The research will be presented at a meeting of the American Chemical Society, and covered at a press conference held on Monday, March 19 at 11 AM CST. A video of the event will be available at ACS Press Conferences.
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