Water & Wastewater Treatment Magazine
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The Works: Leakage ● The roll-out of 20,000 acoustic loggers is the most by any water utility globally For its roll-out of permanent acoustic log- gers in its network, A nity Water is using HWM's PermaNET+ loggers. Launched just over a year ago, this equipment has been deployed in many water companies internationally - with some large deploy- ments in the USA and Hong Kong in particular - although A nity's application of 20,000 units represents the largest use of this kind of equipment anywhere in the world. The loggers are intended to be ˆ tted at 200-400 metre intervals on distribution mains and are located entirely below ground (an advantage for water companies, as above- ground infrastructure usually requires consultation with local authorities or other stakeholders). Each unit consists of a sensor block, which is positioned on a valve spindle where it can 'listen' to vibrations from the pipe, and the logger itself which is secured in the chamber nearby. Data is automatically sent to the control room from the logger via a combination of GPRS cellular communication and SMS, so once installed, there is no need to visit the unit again apart from to change the battery every 5 years. Each unit is tagged with its GPS location, so the information it provides can appear on a map and feed into the " KIT user's GIS system. Its analysis, conducted at night when – ows are low, is aimed at detecting a loud and consistent noise which may be a leak; when such a noise is detected, it sends an alarm together with an audio ˆ le to the user. Because the units are deployed at such regular intervals, simultaneous alarms from two loggers is a reliable indication of a leak between the two points, and the relative sound level can give a good indication of where on the pipe the leak is. Using permanent loggers in this way is vastly less labour intensive than moving mobile loggers around your network, and it is also the only way of being sure that you are picking up leaks of all sizes, according to Mike Tennant, Director of Sales and Business Development at HWM. "If you do a sweep through an area using acoustic loggers you will ˆ nd some leaks, but you will also miss some – essentially, you will ˆ nd the loudest leaks, which aren't necessary the biggest ones. A pipe under pressure with a small hole in it will make a louder noise than a pipe that's actually split in two, but more water is being lost in the second case. A permanent device is the best way of picking up those secondary, quieter leaks that are oœ en the biggest leaks, and therefore driving your leakage down to lower levels." HWM were able to assist A nity with the quick roll-out of the technology (20,000 installed in four months) by developing an app for the installers to use on their mobile phone, explains Tennant. "All the devices were pre-conˆ gured, so they just needed to swipe them with a magnet to switch them on automatically, swipe the barcode on the unit which contains all its details, and take a couple of photographs of the location. The GPS is automatically tagged - that's all done through the app - and the information is all sent up to the database where it loads up automatically. It all enables them to move very, very quickly," he said. Information from the loggers can be easily married up with those from – ow meters in the network, so operators can quickly ascertain how much water is being lost to a new leak and therefore how much of a priority it should be. Operators are able to enter comments about particular locations or leaks, so the company builds up a history of the problems in its network and gains intelligence that can feed into its future programme of improvements. The rapid detection and pinpointing of leaks also means that repair teams can be dispatched quickly, so the total water loss from each leak will be much reduced. An additional beneˆ t is that more targeted repair will ease disruption to the public caused by frequent streetworks. 24 | JUNE 2017 | WWT | www.wwtonline.co.uk ● Using aerial imagery - whether from drones or satellite – for leak detection is another area of innovative technology which Affi nity, and other water companies, have explored and trialled. Last year Affi nity partnered with a company called Utilis, which analyses satellite imagery to detect leaks using advanced algorithmic analysis to track the spectral "signature" of potable water in the ground. This has been used eff ectively by Melbourne Water in Australia among others; aerial imagery may help complement the information provided by permanent acoustic loggers in the network in future. " The Future again apart from to change the battery (20,000