In the developed world, the chances of drinking contaminated water are slim, and even if we do drink some that's stale, usually the most we'll get is a bit sick. But industrial accidental do happen and if the water of a food processing plant or drinking water facility is tainted then the consequences can be catastrophic. If contamination is suspected the technical experts are brought in to take samples, which are sent back to a lab for testing. All of this takes time, and during this period the plant is shut down at huge expense. Weeks later, when the results come back, there may not have even been anything wrong.
Now there may be a solution to this issue. Graduate students at the Technical University of Denmark, have developed a bio sensor which detects microbial contamination in real-time. Students from the university have gone on to create their own company, SBT Aqua.
The bio sensor works by using the impedance flow cytometry, which as the website explains works thus: "A liquid sample is continuously injected into a microfludic channel with integrated electrodes over which a multi-frequency voltage signal is applied. Bacteria and particles transition across the electrodes which results in a changes in impedance. The impedance change for bacteria is uniquely different compared to other non-organic particles, and it is therefore possible to provide a very accurate estimate of both the bacteria and particle count in the sample in real-time. The working principle detects all bacteria species in the liquid sample, as every bacteria will result in a corresponding impedance change when they enter the system."
In the food & beverage and pharmaceutical industries, where huge amounts of water are used and then disposed of, there is increasing pressure to recycle and reuse waste water. However, due to the length of time and the expense of testing this rarely done and it's cheaper and more convenient to use fresh water.
In drinking water reservoirs, governments often require testing of drinking water several times a year and even in the most stringent of countries, water testing is only required once every seven days, thereby leaving a minimum gap of six days in which the water can become contaminated.
But with bio sensors placed wherever the water runs, the water can be continuously monitored 24 hours-a-day, seven days-a-week. The results of which can be sent to a central computer where graphs detailing the biological composition can be analyzed or trigger an alarm.