An army of bacterial robots has been working overtime to purify some of Cincinnati’s water supply and generate renewable energy in the process.

The genetically enhanced microorganisms—dubbed bactobots—were dispatched in early March as part of a $1.7 million pilot project at an Environmental Protection Agency testing facility housed at the Metropolitan Sewer District of Greater Cincinnati.

The project goal is to determine how the technology can be commercialized for use by a range of industry sectors, including municipal wastewater plants and food and beverage companies.

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Stella Sung, CEO of Tauriga Sciences, the company behind the bactobot technology, said, “There’s a huge need for better ways” to clean water for disposal or return to a city’s potable water system. “And there’s a lot of international need, so we’re working to get [bactobots] to China, Hong Kong, India, and the European Union.”

During the pilot program, the bactobots, so named because they labor like machines encoded to perform precise tasks, will be placed in an electrogenic bioreactor, or fuel cell. Wastewater is run through the fuel cell and treated inside it. When oxygen is present, clean water emerges from one end of the reactor; without oxygen, hydrogen gas is produced and throughout the whole process the bacteria are producing electricity.

At laboratory scale, when a mini-reactor is treated with approximately 10 gallons of water, the bactobots generated 5 watts per square meter of anode surface area—or, in laymen's terms, about enough energy to trickle charge a cell phone. An industrial-size reactor would hold millions of gallons of water, Sung said.

Untreated wastewater is a global problem. Each year, 2 million tons of sewage and industrial and agricultural waste is dumped into the world’s waterways, according to the United Nations Environment Program. This contributes to the deaths of 1.8 million children annually from waterborne disease. Even in the United States, thanks to broken pipes, equipment failure, or system overload, untreated sewage is discharged approximately 40,000 times a year, the EPA estimates.

Because Cincinnati processes one of the largest volumes of wastewater in the U.S.—300 million gallons a day, much of it coming from the industrial sector, including Procter & Gamble—the pilot project is ideally located. The waste stress is higher in Cincinnati compared with other locations, said Ting Lu, an environmental engineer working on the project with the sewer district, which means the city has to spend more money and use more resources to treat the detritus.

“If you are using a biological treatment system, it uses more oxygen and increases energy use as well as operation costs, so Cincinnati’s mission is really to find innovative approaches to cost-effectively treat wastewater,” Lu said. “Since we’re looking to save energy and remove high-strength waste, bactobots can bring us a lot of value,” she added.