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Pipe dream: Overcoming waste in water distribution

Region's water transmission systems are highly prone to leakage

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Middle east, Water, Water networks, ANALYSIS

Water transmission systems are prone to leakage, in the Middle East and elsewhere. In spite of a relatively young infrastructure, providers of leak detection equipment are looking at a growth market.

In a region in which water is a scarce, and precious, commodity, the onus is on utilities to minimise non revenue water (NRW), water lost before it reaches the end user. Not only does a great proportion of potable water stem from desalination, a costly and energy intensive process, providers also carry the burden of enabling industrial expansion and catering for
population growth.

This is good news for companies providing leak detection services. “The Middle East is absolutely a growth market for the leak detection business,” says Kevin Laven, solutions manager at the Pressure Pipe Inspection Company (PPIC). “The region fits the three criteria of the profile for an ideal market: high water loss rates, scarcity of available water, and the availability of funds to allow for the detection and repair of the leaks.”

“The Middle East is one of the most attractive markets due to scarcity, demographic and economic development, water linkage to power, recovery for oil and gas and importance for other industries,” agrees Maurizio Selmi,
manager at ABB’s Center of Excellence Onshore.

This is reflected in business growth rates, “Sales of Bentley’s water products have been growing at approximately 25 percent compound in the Middle East in recent years,” says Perrine Parrod, water product marketing manager at Bentley.

The biggest causes of leaks are corrosion, joint failure, and pressure transients, according to Laven. (see box) Because water transmission systems in the region tend to be fairly new, leaks are less common than elsewhere in the world.

According to data recently submitted to the International Water Association, transmission systems in the Middle East and North Africa region have about 60 leaks per 100 kilometre of pipeline.

This is substantially less than the worldwide average of 112 leaks per 100 kilometre. But, as Laven points out, “with each leak losing an average of 150,000 liters per day of water, this amounts to millions of liters every day for many
transmission systems.”

The case for investing in preventing leakage cannot be made better than by research into the cost effectiveness of detecting leaks in large diameter transmission pipes, he believes: “A program of locating and repairing leaks on 100 kilometres of transmission mains will recover, on average, about 17 million gallons per day. This is equivalent to adding a small water treatment plant that costs nothing to operate, at a small fraction of the cost.”

So are utilities in the Middle East doing enough to prevent water, and pecuniary, loss? “While many are not yet, there is definitely a trend towards this. Many cities in the Middle East have water loss levels of over 40 percent. There is a rapidly growing awareness of how big the problem is, and of how great the benefits can be of solving it,” says Laven.

Best practice?
While the need for effective leak detection is clear, determining the best technology and method is a complicated task, given the range of options.

“For water pipelines the technologies used are multiple,” says ABB’s Selmi. “There is acoustic and video technology, there is ground penetrating radar, gas sensing and active network modeling for leak management normally used in oil and gas. It is difficult to establish the best.”

Acoustic technologies are the most economical, according to Selmi, while other technologies and approaches will be used according to the type of network and the requisite cost benefit analysis.

Parrod thinks that flow monitoring is the most effective way of finding out about new leaks.

“Monitoring minimum night flow is the way to determine if there is a new leak in a system,” she says. Once operators are aware of the problem “other techniques, including model-based methods such Bentley’s Darwin calibrator and acoustic devices in combination, can be applied to locate exactly where the leaks are .”

According to Laven, the diameter of the pipeline determines the best way of detection.

“For large diameter pipelines, inline inspection using either our Sahara or SmartBall solutions is unquestionably the most effective. These pipelines tend to hold large numbers of high-volume leaks, and there are simply no other technologies available that can find them reliable.”

“For smaller pipelines and distribution networks, leak noise correlators are the most effective techniques for finding leaks. Of the external technologies available, these are the most sensitive and can simultaneously detect and locate the leaks,” he adds.

Trends?
Do the experts see a trend towards some of the options available?
“Not yet,” says Parrod. “But the model-based method is a growing trend. Bentley expects all larger utilities to be conducting some form of model-based leak detection in the long term.”

Detecting trends is difficult with the multitude of scenarios encountered by operators, thinks Selmi. Factors that have to be taken into account are material, size, whether a pipeline is above ground or buried, and the age of the infrastructure.

Laven does believe that there are certain trends for water detection and water loss prevention.

“There are three major trends. The first is towards the use of pressure reduction, so that the leaks that are present in a system will lose less water. The second is towards external leak monitoring technologies, known as data loggers, which are a type of correlator that is permanently mounted on the pipeline to detect leaks as they occur, thereby minimising the duration of time for which the leak flows. The third is towards inline leak detection programs on transmission mains.”

Prevention strategies
To minimise water loss, utilities should adopt a comprehensive and proactive approach, believes Parrod. “One-off investments in fixing leaks and replacing meters are not enough. Being reactive is much less efficient than being proactive. This entails identifying hidden leaks, optimising repair functions and upgrading distribution infrastructure before its useful life ends.” (see box)

She recommends applying the International Water Association (IWA) best practices, which combine four strategies to address water leakage: active leakage control, pressure management, speed and quality of repairs, and infrastructure management.

And there are other factors that help keep a pipeline in good nick. “In general everything can help to improve pipeline integrity,” thinks Selmi.

“An efficient design of the system is important. Cathodic protection and other integrity methods are common ways to delay
pipeline aging.”

Amongst other things, using the right sort of material is crucial. “The best things that can be done are to select materials that are less prone to leakage, ensure that only qualified contractors install the pipelines, implement good corrosion control programs, and employ a rigorous water accounting system known as a water audit to make leakage problems apparently quickly,” says Laven.

Utilities in the Middle East have made much use of prestressed concrete pipe, which leaks at much lower rates than metallic pipes, he adds. Accordingly, there are fewer corrosion-related leaks, and more leaks from the joints of pipes.

Material difference
Choosing the right material can also be a tricky task, as there is no certainty as to which material actually are the most corrosion resistant. It is clear which materials have been found to have the least leaks: plastic pipes are best in class, followed by concrete, then steel and ductile iron, with cast iron being the most leaky.

There is no clarity, however, whether those rankings are due to the quality of the material, or their time in use.

“It isn’t entirely clear whether the newer materials have fewer leaks because they are resistant to leakage, or if these lower levels of leakage are the result of improved construction practices and less time to degrade,” says Laven. “Only time will tell.”


Prevention is better than the cure
Bentley’s Perrine Parrod thinks a comprehensive prevention strategy includes: 

  • Investment in and utilisation of modern technology to locate and size water loss
  • Development of a District Metered Area strategy
  • Managing assets using historical data for water leakage
  • Making long-term plans for repair, renewal, and rehabilitation
  • Planning investment strategically, using scenario management and cost-benefit analysis

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