Sensor system hides in the sewer to catch polluters
It can be difficult to determine if a business is illegally releasing toxic substances into the sewer. A new sensor system is designed to find out, however, by sampling and analyzing water within the sewer line.
The technology was developed by scientists at Germany's Fraunhofer Institutes for Integrated Circuits and for Reliability and Microintegration, working with colleagues in the European Union microMole project. At the heart of the setup are three rings, each one of which is equipped with sensors, a battery, an energy-management system, a control and communication system, and a micro-pump sampling system.
A robot places the first ring within the sewer line, just upstream from the outlet of a suspected business. The second ring goes immediately downstream of that outlet, while the third is a little farther downstream.
Utilizing a physical sensor that analyzes water parameters such as temperature, pH and conductivity, the first two rings wirelessly communicate with one another, basically comparing notes. If it's determined that the parameters are changing significantly after the water has flowed past the outlet, then the second ring transmits a signal to "wake up" the third ring.
That ring in turn utilizes chemical sensors to further analyze the water, checking for the presence of specific pollutants. If any of those substances are detected, then the authorities are alerted, plus a sample of the tainted water is saved by the ring, for use as evidence in a court hearing. On the other hand, if no pollutants are detected, then the ring automatically dispenses a cleaning solution that flushes out the chemical sensors, leaving them ready for next time.
The technology has already been successfully tested in the lab, and in a length of sewage pipe. Plans now call for it to be trialled in actual municipal sewer lines, within five European cities.