FEATURE FLOW & LEVEL CONTROL CUTTING LEAKS IN A WATER STRESSED WORLD
ABB explains the impact of water leaks and suggests ways of dealing with the issue using technologies such as flowmeters with built-in data loggers
W
ater scarcity is one of the major challenges of our age. As the
climate changes and many landscapes become hotter and dryer while others see more rainfall, the distribution and availability of usable water becomes ever more important. With a global population set to reach
9.8 billion by 2050, and which is becoming increasingly urbanised, getting potable water to these growing numbers of people, efficiently and sustainably, is a major challenge. Fresh water use has risen rapidly over
the last century, rising six-fold since 1900 to reach some four trillion cubic meters per year by the early 21st century and yet the amount of freshwater available has not changed1
. With water sources being increasingly
overused, it’s vital to ensure that the water treated and distributed at so high a cost, is not wasted.
NO ROOM FOR COMPLACENCY Despite the relatively high rainfall in the UK, we have no cause for complacency about our use of water. A staggering 3.2 million cubic metres of water a day, escapes through leaks. Across the globe it is estimated that around 126 billion cubic metres of water are lost through leaks every year. For water companies, this represents an annual revenue loss of $40 billion a year that could otherwise be investmented in water infrastructure. These enormous water losses have
to be replaced, treated and pumped again to maintain supplies to customers. This in turn uses more energy and resources, cutting the sustainability of water operations. Part of the challenge is that most
pipework leaks remain hidden underground. Losses stemming from relatively small but steady leaks from a joint or fitting, can be hard to detect. A big cause of these ‘background leaks’
is elevated supply pressures. While pressure is high, water is forced out into any existing leaks. New leaks can be generated at any points of strain such as joints in the pipework. In fact, a 50 per cent reduction in pressure gives a 65 per cent reduction in leak flow rate2
.
Ofwat requires water companies to fix leaks and reduce them by 16% over the
8 OCTOBER 2020 | PROCESS & CONTROL
next five years. It does not require that 100 percent of leaks be repaired, which would be an impossible demand due to the significant costs of fixing leaks compared to the costs of not fixing them. For water utilities, the cost of not fixing a leak includes environmental damage, as well as the cost of developing new water resources to compensate for the water lost through leaks. This approach is called the ‘sustainable economic level of leakage’ or SELL and ensures consumers get the best value for money.
SNIFFING OUT THE LEAKS In order to control flow rates and pressures and thus leaks, we need to know where they are. Electromagnetic flowmeters
offer improved accuracy over a
Ofwat requires water companies to fix leaks and reduce them by 16% over the next five years
Measurement of flows was a major
factor in the ability of Scottish Water to reduce its leakages, saving a staggering 1,000 pipe bursts in three years. New thinking and technologies are
shaking up how water companies find leaks. One such technique is acoustic loggers. Each unit incorporates a sensor block, which ‘listens’ to vibrations from the pipe, and the logger itself. Each unit is tagged with its GPS location, so the information it provides can appear on a map. Alarms from two loggers are a good indication that a leak exists somewhere in the few hundred meters between their locations. Other techniques involve laser beams
transmitted through fibre optics. Vibrations caused by water leaving the pipe alter the refection of the laser beam pulse, signaling a leak.
range of flows and are suited to measuring the
low flow seen at night and spot any unexpected increases that might indicate a leak. In fact, modern meters could even detect a toilet flushing they are so sensitive to increases in flowrate.
TOTAL FLEXIBILITY An example is ABB’s AquaMaster4. Its built-in Data Logger runs at high speed, giving the user total flexibility to download logged data frequently, every fifteen minutes if needed. The user can then investigate, in precise detail, flow and pressure activity during a period of interest, at even higher time resolution. Such high-resolution data aids step testing, leakage detection and water network analysis.
ABB’s AquaMaster4’s built-in Data Logger runs at high speed, giving the user total flexibility to download logged data frequently, every fifteen minutes if needed
SPACE DETECTION TECHNIQUES Utilities are also turning to space detection to combat leaks. A technique originally designed to detect water on other planets can capture detailed images covering 3,500 square km at once. The imagery is analysed to detect leaks and unusual amounts of water. Positions of incidents are sent to a team of technicians on the ground, for follow up investigations and repairs. We as consumers must all do our bit
[1]https://ourworldindat
a.org/water-use-stress
[2]https://www.waterwo
rld.com/international/pot able- water/article/16201852/l eakage-reductions-the- fundamental-role-of- pressure-management
too. If we could cut personal consumption to just 100 litres a day and reduce leaks by 50 percent, we would have enough water for 20 million more people, without taking any more from the environment. Being prepared to detect leaks in new
ways with new techniques shows commitment to solving the problem of water stress and helps convince customers that they should also play their part in solving it.
ABB
www.new.abb.com
/ PROCESS&CONTROL
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