With millions of litres of water seeping out from the world’s pipes every day, Ian Randall finds out about a sure way to reduce leaks and bursts.
Across the world, millions of litres of water are seeping out from supply networks every day before they even reach our taps. Replacing pipes is enormously capital intensive, while digging up the road to fix all of the small leaks which together add up to big losses is costly and disruptive. A cost effective alternative is to optimise the pressure of the water in the pipes, keeping it high enough to meet customer needs, but eliminating the excess, which causes leakage and burst
Technology from the UK-based company i2O uses sophisticated software and a network of sensors and controllers to do just this. Its novel systems are already saving over 75 million litres of water each day around the world.
“Leakage is a worldwide problem”, says Adam Kingdon, the CEO of i2O. “Optimising the pressure in the network seems like a very obvious thing to do. If you manage the pressure correctly, you can reduce both leakage and the number of new bursts as well as reducing operating costs and energy bills.”
Most major water networks are divided up into District Metered Areas (DMAs), each covering a few thousand homes or buildings. A pressure reducing valve (PRV) is usually installed at the inlet of each DMA. These PRVs are set to a fixed pressure and are currently adjusted manually by technicians visiting site.
The problem with this approach is that the pressure required fluctuates with demand, throughout any given day and over the course of a year. As the PRVs are difficult to adjust, they are normally set at the maximum pressure that might ever be needed. This means that for the rest of the time, they are set far too high.
The excess pressure increases leakage, which is proportional to pressure. It also causes additional stress in the pipes leading to bursts and reduces the service life of the pipe. Pumping at too high a pressure is also enormously wasteful of energy.
This waste can be avoided through the use of i2O’s solution, which is both simple and effective. So, how does it work?
The company retrofits each PRV with a patented pilot valve and remote controller. Sensors placed downstream in the pipe network – at the ‘critical point’ where pressure is lowest – gather data on demand, which is transmitted via the mobile phone network, together with data from the PRV controllers, to i2O’s server. Software is then used to set the PRVs automatically and continuously to the optimum pressure, without the need for, and costs of, manual interventions.
This way, the whole network can be regulated to ensure not only that customers always receive the pressure that they need, but that the pressure (and therefore the amount of leakage, risk of bursts and cost of pumping) is kept to a minimum. This lowers operating costs, enhances the lifetime of the pipes and reduces the service disruption to customers through lengthy repair jobs.
As there is rarely mains electricity at the PRV site, i2O developed an innovative pilot valve, which is retrofitted to the PRVs and uses minimum power, supplied either by a local battery or by a micro-turbine inserted into a bypass pipe.
The company’s 2010 installation on Veolia’s network in the UK reduced leakage by approximately 15% (around 2.5 million litres of water a day) – while actually improving customer service levels and eliminating customer low-pressure complaints. In addition, Veolia estimated that, due to a reduction in bursts, operating costs fell by as much as 80%.
One of i2O’s most successful installations has been in Malaysia, in partnership with the water services companyJalur Cahaya. Here, 205 systems on the Syabas network save 40 million litres of water a day, or 12% of the total volume. In addition, the rate of new pipe bursts has fallen by 40%.
“On [zones] with i2O, once we have fixed a leak, it stays fixed,” says Sheikh Mazlan of Jalur Cahaya.
“Using smart systems to actively manage pressure in a water network has huge advantages”, says Jacob Tompkins, Managing Director at Waterwise, an independent UK based non-profit organisation which works to promote water efficiency and conservation. “[This] isn’t just a fit-and-forget approach”, he adds: “It is a tool that can aid in network management, [by providing] the ability to vary pressures in distinct parts of the network in real time.”
Ian Randall is a journalist working at CERN.