Sensors in sewage tunnels can detect bomb makers EMPHASIS system was created by the Swedish Defense Research Agency Sensors are placed in sewers to detect chemicals used in bomb making Chemicals are detected either because they have been poured down the drain or ingested into the terrorist's blood stream and then excreted Once detected, the information is sent to a command centre A mobile unit then uses infrared lasers to scan the areas for gas molecules These molecules can help further pinpoint the location of a bomb maker Plans for the next stage in the fight against terrorism could be in the toilet - quite literally. Swedish scientists have developed sensors that can be fitted inside waste tunnels and used to detect bomb making chemicals in sewage. If suspect chemicals are detected, the sensor alerts the authorities who can carry out infrared laser "sweeps" above ground to locate the precise location of the bomb-making factory. The Swedish Defence Research Agency has developed sensors fitted inside tunnels, such as the one in this stock image, that detect bomb making chemicals in waste. It uses 'ion-selective electrodes' to determine trace elements. If the level of ions is high enough to arouse suspicion, the system alerts the authorities EMPHASIS is made up of a "network" of sensors plotted above and underground that can detect chemicals in liquid waste, and detect gas vapours. Each sensor contains "ion-selective electrodes" that sit in the flow of waste water in sewage tunnels. If a bomb-maker flushes chemicals down the toilet, or the chemicals and gases from bomb making are ingested into the person's blood stream and ultimately enter their urine or faeces, these chemicals will pass through the sensors. The ions that are found in these chemicals will travel through the electrodes and change a resistor's voltage. This change is recorded and tracked using software designed to seek out even the smallest traces of suspect ions. The system is called EMPHASIS, which stands for Explosive Material Production Hidden Agile Search and Intelligence System. Developed by the Swedish Defence Research Agency (FOI), it is made up of a "network" of sensors plotted above and below ground that can detect chemicals in liquid waste, and detect gas vapours. Each sensor contains "ion-selective electrodes" which are around four inches long and sit in the flow of waste water in sewage tunnels. If a bomb-maker flushes chemicals down the toilet, or the chemicals from bomb making are ingested into a person's blood stream and ultimately enter their urine or faeces, these chemicals will pass through the sensors. The ions that are found in these chemicals travel through the electrodes and change the built-in resistor's voltage. This infographic explains the concept behind the EMPHASIS sewage detection sensor network. If a bomb-maker flushes chemicals down the toilet, or the chemicals from are ingested into the person's blood stream and ultimately enter their urine or faeces, these chemicals will pass through the sensors If the ions are found in "elevated amounts," data about the type of ions, the approximate location based on the proximity of the sensors, the time and the level of ions detected are sent to a command centre. Mobile units armed with infrared lasers then carry out a scan of the nearby area in a bid to detect suspect gas molecules and narrow down the target area. As the target area is narrowed, extra sensors are placed in the sewers around that area to pinpoint the precise location. If ions are found in 'elevated amounts', data about the type of ions, the approximate location of based on the proximity of the sensors, the time and the level of ions detected are sent to a command centre. Mobile units armed with infrared lasers, pictured, then carry out a scan of the nearby area in a bid to detect suspect gas molecules and narrow down the target area EMPHASIS is an EU-funded project for the "detection of production of explosives." The objective of the EMPHASIS project is to test a system for detecting 'ongoing illicit production of explosives and improvised explosive devices in urban areas.' According to the FOI website: "The goal of the EMPHASIS project is to test a system concept for the surveillance tool of tomorrow for detection and localisation of illicit bomb factories in urban areas." The team have already successfully tested the sensors in waste water inside a lab and intend to trial the sensors in sewers next year.