Water & Wastewater Treatment Magazine
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24 | APRIL 20XX | WWT | www.wwtonline.co.uk At the other end of the spectrum are in-pipe inspection technologies: devices that are inserted into water mains and pipelines and move along them providing data on the condition of the pipe wall. One company gaining a lot of attention in this field is Pure Technologies, which markets both a free-swimming, spherical device (SmartBall), and a system that remains tethered to the surface (Sahara). Both are capable of identifying very small leaks, within 1.8m of their location, and can also pick up air pockets which might cause problems in future. SmartBall can remain in the pipe for up to 17 hours at a time, allowing inspection of long pipeline sections; it was recently used by WRc for a United Utilities pipeline inspection in Cumbria, its first use in the UK. Technologies that help tackle leakage generally fall into one of three categories: those that help locate leaks, those that help mend them once they are found, and those that help prevent leaks in the first place. One technology in the first category is helium injection, whereby helium gas is inserted into working large-diameter pipes. Helium is lighter than air and rises naturally to the surface, and will only be able to exit the pipe through a leak or breach; detecting its presence on the surface can therefore indicate with high accuracy where the leak is below. A system using this method – iDroloc – was developed by Suez Environnement Water Advanced Solutions UK (formerly Aqualogy) and has been used in Spain, Saudi Arabia, the USA and France. It has not yet been used on a significant scale in the UK, although Dee Valley Water has recently started using it for the testing of new pipelines. Other tracer gases have been used in the past for leak detection, but one big advantage of helium is that it can safely be mixed with the pipeline water so there is no need to take the pipeline out of service while carrying out the test. Another area of development for leak detection is satellite imagery. Technology available from Israeli company Utilis, adapted from a tool used to search for water on other planets, can seek out the 'spectral signature' of pure water in imagery captured from a satellite survey of an area. When this data is combined with geographical information systems (GIS) showing the location of pipelines, and subjected to algorithmic analysis, the technology can identify the presence of leaks with a high degree of accuracy. Thousands of kilometres can be covered at once and the method can be used to produce a survey report of likely leaks on a monthly, quarterly or half-yearly basis. Innovation Zone: Leakage Locating the leaks ● Minimising leakage from the pipe network is a perennial challenge for water utilities. In the first in a series of WWT Innovation Zone specials, we take a look at the latest technologies that can help zero in on hard-to- locate leaks THE CHALLENGE Leakage of treated water from the pipes in the distribution system is a reputational as well as a financial issue for the water industry; customers do not appreciate seeing valuable water going to waste, especially when they themselves are being asked to use water resources efficiently. Leakage is calculated by working out the difference between the amount of water going into supply and the amount used by the customer (so- called non-revenue water) and targets for reducing it have been set since privatisation. In 2014-15, the industry lost 19.6% of all water put into supply. Some of the largest water and sewerage companies have the biggest leakage problems: United Utilities (26%), Severn Trent (25%) and Thames Water (25%) all leak around a quarter of water put into supply. Improvements to leakage rates have been made over the years, but since 2011-2 they have been creeping up again. Because percentage figures for leakage can be misleading, Ofwat sets targets for each water company in terms of megalitres lost per day. The industry as a whole leaked 3,135 megalitres per day in 2014-15 and if all the water companies met their targets by 2020, this would fall to 3,042 megalitres. Leakage creates two other related risks for water company performance. First, mending bursts and leaks might entail taking customers temporarily out of supply, which hits another important performance metric; second, leaking pipes can lead to water quality incidents if surrounding contaminants are allowed to enter the pipes. With a vast network of ageing pipes in the UK a proportion of leakage is inevitable, and some leaks do not currently make economic sense to fix. However, a recent UKWIR research group has challenged the industry with the aspirational target of achieving zero leakage by 2050. 3,135 Million Litres a day of treated water are lost to leakage Utilis's technology uses satellite imagery Helium leak detection Pure Technologies' SmartBall