Right now, detecting contaminated water can take days, and that puts humans and animals at serious risk. But a new biosensor developed by grad students in Denmark promises to spot unclean water in an instant, and whether it's used in a village well in a rural community or a huge food production factory in the city, being able to spot contamination without lab tests or technical experts ensures the problem is caught before it has the chance to do damage. 

"I believe that our product will revolutionise the way microbiological water quality measurements are made," said Erik Gustav Skands, a graduate students from the Technical University of Denmark and CEO of the tech startup, SBT Aqua. The team behind the invention hopes to bring it to market some time next year.

The new sensor works through a technique called impedance flow cytometry: liquid is monitored via electrodes that carry multi-frequency voltage signals, and when bacteria and particles hit the electrodes, the impedance is affected. Because the impedance change for bacteria is uniquely different from other non-organic particles, the sensor can indentify with a high degree of accuracy whether or not the water is contaminated. What's more, the whole system requires very little in the way of maintenance.

"Today, all commercialised technology to detect bacteria requires either staining, incubation, or manual sample-handling," explains the SBT Aqua team. "SBT Aqua will offer a product, which can perform online and real-time measurements of the bacteria level in aqueous solutions with no pretreatment of the sample, no incubation time, and no manual sample handling."

Sensors can be placed throughout a particular network to detect problems at any particular point, and of course, there's no need to stop the flow of water to take samples - everything happens in real-time. You can think of it working in the same way as a smart sensor in a home, where conditions are continually monitored and an alert can be generated as soon as something doesn't look right.

The biosensor developers cite the example of their own home country of Denmark, where water samples are only taken once a week at best - leaving a seven-day window where people could be at risk. Having already won several awards for their work, the three graduates behind SBT Aqua are now working hard on product development and testing, ready for a commercial launch in 2016.