Wednesday, June 12

Electric Feel: Special Bacteria Help Detect Water Pollutants

What happens when scientists and governments know that a body of water is polluted, but can’t test for toxins due to the expensive equipment?

The University of Bath brings in their electric bugs to test the waters.

Scientists from the university’s Department of Chemical Engineering have recently developed a low-cost and effective device that is intended to be used by developing countries in order to help them monitor their drinking water in real time. This real time data feedback will omit the need for expensive lab equipment.

Water pollution cause by industrial waste is a serious problem in developing countries as many governments dismiss the need to monitor environmental impact as production takes top priority to improve the nation’s economic standings. More developed countries already have water remediation systems in place as a way to keep sanitary conditions for citizens — yet these systems are often pricey (though very effective).

In the United States the remediation and environmental cleanup industry generated around $18 billion.

Current methods for detecting water pollutants are very time-consuming and require a specialist with years of in-the-field experience. Yet this new device, created using 3D printing technology, can be used directly in rivers and/or lakes and is able to give continuous feedback on water quality.

The University of Bath worked alongside with Bristol Robotics Laboratory at the University of West England to create the device that contains special bacteria that give off an electric current when they feed and grow. When placed in a polluted water source, these bacteria have been found to decrease their electric current output, signifying that there are pollutants.

“We found that when we injected a pollutant into the water there was an immediate drop in the electric current [the bacteria] produced,” said Dr. Mirella Di Lorenzo, Lecturer in Chemical Engineering at Bath. “The drop was proportional to the amount of toxin present and the current is recovered once the toxin levels fell.”

Although the device can monitor pollutants, water remediation techniques and systems may still be needed to remove such toxins. Right now, primary and secondary waste treatments remove 85% to 95% of pollutants from wastewater before it is disinfected and discharged back into local waterways. However, the invention is still a big step to water monitoring.

“This means we are able to monitor the level of pollutants in the water in real time without having to collect multiple samples and take them to a laboratory,” said Di Lorenzo. “Because this system uses live bacteria, it acts a bit like a canary in a mind, showing how these chemicals affect living organisms.”

Only 3% of the Earth’s water is fresh water, and at the moment using methods such as mass spectrometry to determine if toxins are present is very costly. With nearly 400 billion gallons of water being used in the U.S. alone, these electric bacteria could be useful for any nation suffering from severe water pollution.

So far, the device is able to detect trace amounts of cadmium, a polluting material used in the electronics industry. The team hopes to improve the toxin-detecting spectrum in the next few years.

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