Innovative Solutions
Advanced technologies deployed by KWA for leak detection
Managing the level of non-revenue water (NRW) has become a prime concern of water authorities. In urban India, a significant quantum of water provided by the service utilities remains unaccounted for because of illegal connections, water thefts and leakages in the distribution system. Faced with similar issues, the Kerala Water Authority (KWA) has started adopting advanced technology solutions for easier and more effective detection of leakages. While some of the solutions, such as SmartBall and Sahara, are based on highly advanced leakage detection technologies, conventional tools are also being deployed by the water authority.
Current scenario
Presently, the KWA manages a total of 2.6 million domestic water connections as against a population of 30 million. Other than street pumps, all the water connections in the state are metered. Further, of all the water meters, 95 per cent have been working efficiently.
One of the main issues faced by the authority is low coverage of water connections. Further, it lacks the capability of tracking water from the production side, resulting in the NRW level being as high as 40 per cent. Of the water supplied in the state, 40-50 per cent is not billed for. Another issue is with respect to the dated pipeline network. Because of the aged water network, about 50 per cent of the leaked water does not reach the ground surface, making it virtually impossible to detect the exact location of the leakage. Other challenges include intermittent water supply and recurring operations and maintenance costs.
Initiatives taken
The KWA embarked upon a pilot leak detection study in 2004, with the primary aim of reducing NRW levels in the state. The study was conducted in Coimbatore and Kozhikode, with assistance from the Japan International Cooperation Agency. It showed high NRW levels in both the cities, primarily due to under-reading by the installed meters. In order to address the problem, the KWA purchased equipment for detection of leakages in pipes in 2008, following which a dedicated NRW unit was set up in 2012.
Since then, the KWA has been using a variety of innovative methods for identifying the sources of leakages. In the case of a major leak at Trivandrum, the acoustic leak detectors deployed at the time were not able to locate the location of the leakage. The authority then used the sequential valve closing and controll of flow method for identifying the leak source. In a similar instance, a water shortage was reported in Nattika village of Thrissur district. Suspecting unidentified leaks, survey works were carried out in the main distribution pipeline which showed inadequate inflow of water at a nearby water plant. Repeated measurements at various points revealed leakage of 3 million litres per day in the main pipeline. Leak detectors were then deployed to identify the exact location of the leakages so as to rectify them.
The KWA has also been instrumental in deploying advanced leakage detection tools for easier and faster detection of leakages in water distribution pipelines. SmartBall is one such technology being deployed. It is a free-swimming foam ball with instruments inside an aluminium alloy core. It calculates the location of a leak by detecting acoustic pulses emitted by the ball at receivers attached to pipe appurtenances. The location of the leak relative to the receiver position is determined by analysing the arrival time of the pulses. This survey method has been deployed by the KWA in a number of other instances for identifying leakages.
Another technologically advanced method adopted by the KWA is the Sahara pipeline inspection system. The Sahara system can be deployed for detecting leaks, air pockets, inline valves, branches, and redundant and illegal connections. The system can also detect structural issues such as corrosion, tuberculation, presence of debris and partial blockages in waste and sewage mains. Utilities can track the sensor through a precision locator known as the Sahara locator, which is equipped with an extremely low-frequency transmitter that can be detected by sensors inside the pipeline. This enables easy communication and accurate data collection through pipelines.
Currently, the KWA boasts of a variety of equipment for detecting leakages, ranging from mechanical listening sticks to electronic listening sticks, ground microphones (Omikron) and leak noise correlators (ZetaCorr). It is also equipped with flow and pressure measurement instruments (ultrasonic flow meters and flow and pressure loggers) and underground asset detection and mapping instruments (metal valve locators, metallic pipe locators, non-metallic pipe locators and ground penetrating radar).
The way forward
Water authorities in the country have started taking initiatives, using both conventional and advanced techniques, to reduce NRW levels and plug leakages. Going forward, the full potential of the advanced technologies can be realised only when the concerned agencies deploy skilled manpower as well.
Based on a presentation by Praveen K.S., Executive Engineer, Operations, KWA, at a recent India Infrastructure conference