Smart Sensors for Water Leaks

Smart Sensors Warn Instantly of Citywide Water Leaks

IN MAY, a water main sprung a leak under downtown Singapore. In a dense island city with scarce water resources, an undetected leak could have been a disaster, damaging underground infrastructure like subways and sewers, possibly even eating its way up to street level before anyone noticed. But a network of sensors, the first of its kind, spotted the sudden drop in water pressure, traced its location and scrambled a team of engineers before damage could spread.

Designed by a company called Visenti, a spin-out of the Massachusetts Institute of Technology, the Waterwise network is distributed across the Singaporean water grid. About 130 sensors take readings every millisecond, sampling the pressure far faster than existing systems, which typically sample once every few minutes. When a pipe springs a leak, the pressure change sweeps through the whole mains network. Visenti's sensors pick up changes at multiple points across the network, sending the data to a central server that triangulates the signal back to the leak's source.

The system can often tell more about what's going on than on-site engineers. Ami Preis, a co-founder of Visenti, says the system measured the Singapore leak as a big one. "But when engineers got to the site they said the leak is not that big. Then they started digging there, and they saw the leak was as bad as we told them."

"Singapore is quite ahead of the game in managing water distribution," says Jean-Pierre Bardet, director of the Urban Water Institute at the University of Texas at Arlington. "They are on an island without much water, so they have to be creative about managing it."

Visenti's sensor technology is now being rolled out to other big cities in Asia and Australia. Hong Kong and Melbourne have just installed their own networks, and Visenti is gathering data in Sydney as part of an upcoming deployment there.

As urban populations swell in the face of water supplies that are roughly static in quantity and geographical distribution, water grids need technology like this to keep up with demand.

There is plenty of room for improvement. In the US, many pipes date back to the mid-19th century. Water mains in Philadelphia, Pennsylvania, leaked a third of what they carried in 2009. In Cleveland, Ohio, the figure was 29 per cent.

Ireland is blessed with abundant fresh water resources, which may explain why it can afford to lose about 350 millilitres for every litre entering the grid. Many other countries face similar losses due to poor infrastructure.

By catching leaks before they get out of hand, technology like Visenti's can conserve water and save on the energy required to pump it.

Visenti also has sensors that go beyond keeping tabs on leaks: they measure pH, temperature, electrical conductivity and other properties that can be used to sniff out water contamination.

Nearly all urban water systems do this kind of monitoring as water enters the network, but almost none of them do so as it reaches the tap. Bardet says monitoring across a network can help assure customers that their tap water is safe and good to drink, something that's especially important as desalinated and directly recycled waste water become an essential part of supply in growing cities.

Much of the world can't readily have a water system with the same efficiencies as Singapore's, Bardet says. "Infrastructure is not ready for it," he says. "It's ageing. It's really hard to do new things with old pipes." Large amounts of money were spent to build water mains in developed countries, often more than a hundred years ago, but the same level of investment is not going into maintaining that infrastructure."One of the big challenges with water in the US is that it's too cheap," says Eric Williams, a water engineer at the Rochester Institute of Technology in New York. "There's no economic incentive to care how much you use."

Not all solutions need to be high-tech, though. Situated in the Nevada desert, the city of Las Vegas has always been on a tight water budget. Its response has been to build a system that recycles nearly all water used indoors. Waste water is captured, treated, then pumped into a specially created marsh - called the Las Vegas Wash - which serves as a giant natural filter, before emptying intoLake Mead. The city then draws "new" water from the lake, treats it, pumps it to homes and businesses, and the cycle continues.

Real-Time Pipe Breakage Detection

Advanced High-Rate Pressure Sensing Integrated with Cloud based Analytics

Visenti's LeakIntel™ system is comprised of high-rate (250 samples/sec) pressure sensors installed at optimal locations. These sensors transmit continuous information about the condition of the pipe network to a Cloud-based data management and analytics engine.

The LeakIntel™ system identifies the pressure transients generated by potential pipe breakage and localizes the event to the faulty pipe with high likelihood.

High-Rate Pressure Sensors catch pipe break events 24/7 in Real-Time

When a pressurized pipe breaks, it releases a high-rate pressure transient that propagates along the pipes in very high velocity. LeakIntel™ is a unique system that can capture these short-term leak related transients before they are dampened. It localizes to the faulty pipe and prioritizes the pipe failure criticality (leak magnitude & impact on consumers) to allow immediate & timely response with minimum impact on network integrity. Distractions are minimized, because this real-time intelligent machine learning system filters out false alerts.

Real-Time Notifications

LeakIntel™ is an automated system supported by Visenti's 24/7 Control Center. Once a critical leak event is identified, Visenti's Control Center is activated to respond to the alert and the most relevant network operators are notified.

Pipe Repair Operation Simulation and Impact Assessment on Mobile Plateform

A leaking pipe can be difficult to isolate and repair. In dense pipe networks, it can take significant amount of time to identify an appropriate set of valves needed for isolating the leaking pipe. It can also be tough to assess the impact of the unexpected pipe isolation on the rest of the network.

LeakIntel™ incorporates the network GIS data, pipe network model and live pressure data to automatically identify the locations of the valves needed to be shut-off in order to isolate the leaking pipe. And if a valve is faulty or stuck, LeakIntel™ instantly identifies alternative valves to shut off.

This system also notifies in case there is a negative impact on the rest of the network such as low pressure or interruption of supply to key customers. This prevents unintended consequences of the repair operation.

LeakIntel™ is available on mobile devices too; all the simulations can easily be done while in the field, during the operation. This saves time, money and minimizes damage to the environment from trial and error.

Source: NewsScientist

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Taxonomy

• Technology
• Sensor Systems
• Leakage Reduction