US scientists look to bacteria to detect hydrocarbon leaks from pipelines
21 March 2018
Scientists from Mississippi State University (MSU) in the US are looking to develop live sensor systems using electrogenic bacteria which could help identify leakages in oil pipelines in real time, and a larger version of the sensor could be deployed to help clean-up efforts.
"Certain microorganisms degrade or eat contaminants and, in the process, produce some electrical voltage," said Veera Gnaneswar Gude, an environmental engineer at MSU. Speaking at a meeting of the American Chemical Society (ACS) in New Orleans, he said a team he was leading was looking into whether bacteria-based sensors attached to the exterior of pipes could work in tandem with existing equipment to improve detection and response time.
At the moment, pipeline operators monitor their infrastructure a number of different ways. They may hire technicians to walk along the conduits with handheld sensors that search for gas emissions from hairline cracks. They may scan the network from the air, using drones, planes or helicopters equipped with lasers or infrared cameras. Or they may send a cylindrical, sensor-laden machine called a "smart pig" through the pipe to inspect it internally.
But still, accidents happen. According to the Pipeline and Hazardous Materials Safety Administration, more than 11,700 oil and gas pipeline incidents occurred in the continental United States between 1998 and 2017, costing the industry more than $7 billion and resulting in 1,296 injuries and 334 deaths.
Scientists already know that some microorganisms that live naturally in soils and ocean water can feed on hydrocarbons like methane, ethane, butane, propane and pentane. Colonies of them bloomed and thrived on the oil spilled from BP's Macondo well during the Deepwater Horizon disaster in April 2010. Other microbes that take in chemicals and produce electrons as a byproduct have been well studied for use in microbial fuel cells that remove pollutants from wastewater and at the same time generate electricity.
Gude's new sensor works like a battery based on microorganisms that live in marine waters and sediments. On one side is an anode made from a porous membrane that contains a concentration of hydrocarbon-loving microbes. When molecules from hydrocarbons pass through the membrane, the organisms eat them and send electrons across a resistor that regulates and measures the flow of electrons as they move toward the cathode. At the cathode, a colony of electron-eating bacteria enjoy a meal.
Under normal circumstances when there is no leak, the microbes feed naturally on organic compounds in the water or soil. But when they find a hydrocarbon feast, their metabolisms increase, causing a spike in the electrons. This spike can be measured by the resistor or a tiny circuit in the cathode. If the spike goes over a threshold, the sensor could emit a wireless signal that notifies a technician.
Gude said that he would like to develop a sensor that works not just on pipes, but also on tankers, trucks and storage tanks. Eventually, he wants to develop a larger system that would also gobble up spills to reduce cleanup efforts.