Scientists at the University of Essex have helped design a robotic fish capable of monitoring pollution. The fish, which measures about 1.5m long, may be a little larger than its real-life counterparts, but the movements closely mimic them. This construct of carbon fibre and metal, dubbed ‘robo-fish’, is a machine capable of autonomously hunting down contamination in the water, and feeding this information back to the shore for analysis. These robotic police are currently being developed for use in harbours, but their use will eventually expand into other areas such as coastal waters, estuaries and rivers.

Ports and harbours a can be challenging places to routinely monitor. The use of these robotic patrols will aid not only recognising when waters have been contaminated, but will also help determine the source of contaminants. For example, a ship entering a harbour could leak some dangerous chemicals, unbeknown to anyone, and depart to other waters, continuing to spread pollution unchecked. Under commonly used old fashioned methods, such as those currently employed by environmental agencies and consultancy companies, many areas of water are only monitored periodically, and even then often in the same locations; with lengthy time periods between sampling, transport and lab analysis,  an accurate picture of the conditions of water in different areas, depths and times remains unknown.

The Department for the Environment Food and Rural Affairs (Defra) has estimated that in England and Wales alone, the cost of water pollution in rivers, canals, lakes and coastal waters is approximately £1.3bn per annum. The concept to use remotely operated robot fish, which can be quickly and easily deployed in shallow waters, and which can constantly patrolling the harbour, will enable constant checking for pollution, rapid response for decision making and counteractive action to be taken.

The fish use micro-electrode arrays to sense contaminants; In their current form they can detect phenols and heavy metals such as copper and lead, as well as monitor oxygen levels and salinity. The team have also tried to build flexibility into the design, including a removable chemical sensor unit, which can be replaced with an alternative sensor, such as one that monitors sulphates or phosphates, depending on the environment. Once the robotic fish has detected a problem, it uses artificial intelligence to hunt down the source of pollution. They can work alone or in a team, communicating with each other using acoustic signals and they can continuously report back to the port.

"When we have our prototype, then we'll know what needs to be done to make this a complete commercial system. We hope it could happen in the next few years," said Dr Speller. "In the future, what I'd also like to see is not just a single task robot, but robots that can multitask - robots that can do search and rescue, monitoring for underwater divers, at the same time as tracking pollution."

By Will Matthews

Photo courtesy of Elsie esq.