Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/515382
34 | JUNE 2015 | WWT | www.wwtonline.co.uk In the know Digging deeper: leak detection an innovative leakage solution that offers a more precise and effective alternative to conventional acoustic methods. iDROLOC detects water leaks in both long-distance, large-diameter pipelines and in small distribution pipes and connections, where acoustic systems are not a feasible option. The new technology substitutes sound waves for helium gas. It operates on the basis of two premises: that helium is lighter than air, therefore it tends to rise naturally to the surface; and that the helium concentration in the earth's atmosphere has a constant value. These two principles make helium gas a unique tool to detect leakages in pipes. The system is able to trace leaks with no interference to noise vibrations. Furthermore, it is also suitable for any kind of pressure condition. This means that when iDROLOC is operating, the pipes can remain in service throughout the process, without the need for any preparatory operations such as closing valves or modifying pumps; the final consumers are therefore the ones who benefit the most from its implementation. First stages In 2009, Suez Environnement Water Advanced Solutions began working hard to design a tool for inspecting leakages in large diameter pipes. At that time, the market offered other tracer gases as an alternative to acoustic methods, but these gases always meant having to put pipelines off-line, implying long interruptions to the water service. Engineers at Suez Environnement Water Advanced Solutions realized that helium's qualities could be very valuable when applied to tracer-gas techniques. They would not require cutting the water service. AŠer several trials, the first pilot was carried out in 2010 in Alicante, Spain. The results were promising and, months later, Jeddah in Saudi Arabia became the first international city to take advantage of iDROLOC's benefits. Many countries around the world are now using it for detecting leaks, including Spain, the USA, France, Mexico and Colombia. It has yet to be Five advantages of helium leak detection used in the UK, although Drinking Water Inspectorate (DWI) regulations do allow for the injecting of helium into the main drinking water network, in service, to pinpoint leaks. How iDROLOC works iDROLOC operates through two main phases: injection and aspiration. A stainless-steel injection kit ensures that liquid helium is correctly inserted upstream of the section to be inspected. This system calculates the amount of gas needed, depending on the water volume and pressure. The helium is absorbed by the water, which transports it at a uniform concentration. It flows through the pipes without causing contamination or affecting the water's smell and taste. Helium releases naturally from the water as a gas, and rises because it is lighter than air, making it easy to detect in the subsoil. If there is a leak, the helium will be released from the water, which soaks through the soil. A robot works continuously and takes samples every three metres to detect even the smallest leak. It drills a hole in the area selected and a series of suction cups extract air from the sub-soil. The gas analyser examines the air, looking for the presence of helium. As the concentration of helium in the atmosphere is stable, any increase indicates an anomaly that iDROLOC pinpoints as a problem area. This detection stage can be carried out for up to five days as the helium is retained in the soil for this period. 1 It is unaffected by interference from sounds or vibrations, which can impede the detection of leaks using traditional acoustic systems 2 Pipelines can remain in operation while it is working and there is no need to modify water volumes or pressure 3 Leaks can be detected in pipes of any size and material, from large pipes, where acoustic methods cannot be applied, to individual mains- connection pipes . 4 The equipment can be used by a single operator with fully portable equipment (at a rate of 1km of piping per operator per day) 5 Inserting helium into pipes has no effect on public health or on the quality of water. iDROLOC uses portable equipment to detect helium leaking from the pipes About the author: Nick Haskins is Business Development Manager at Suez Environnement Water Advanced Solutions UK, previously known as Aqualogy.