Growing urbanisation in the country has increased the pressure on the existing water and wastewater infrastructure. Despite being a crucial survival resource, water is grossly wasted across the world. It is estimated that one-third of the world’s water utilities are losing around 40 per cent water due to leakage. In India, too, more than 40 per cent of the water produced in many cities is wasted before reaching the end consumer due to leakage or theft. This underscores the need for smart, real-time monitoring to strengthen utilities with effective control over water usage. In this context, there is a growing demand for leak detection solutions to improve asset efficiency, reduce non-revenue water (NRW) losses and meet the water conservation goals.
Pipelines are widely used for the transportation of fresh water to domestic, commercial and industrial consumers. The pipelines are designed to withstand several environmental loading conditions in order to ensure safe and reliable distribution from the point of production to the shore or the distribution depot. However, owing to the ageing pipeline infrastructure and lack of proper maintenance mechanisms, leaks are bound to occur. In India, the government and urban local bodies are making constant efforts to reduce pipeline leakages by using the latest technologies, which will allow inspectors to precisely determine the location and the severity of the leakage.
Industries are also becoming receptive to the idea of deploying advanced technologies to treat effluents, as well as recycling and reusing them for industrial purposes and green belt development. Further, they are undertaking a detailed mapping of assets and underground utilities, and deployment of leakage control technologies to curb losses due to the increasing level of NRW.
Many methods have been adopted to detect leakages in the water pipeline network. The external methods mainly involve the use of specific sensing devices to monitor the external part of the pipelines. Among these, acoustic detection is the primary means of detecting and locating pipeline leaks. It is described as the systematic method of using listening equipment to survey the distribution system, identify leak sounds and pinpoint the exact locations of hidden underground leaks. Accelerometers are another type of vibro-acoustic measuring device useful in monitoring low frequency pipe-shell vibrations. The use of both accelerometers and hydrophones for monitoring pipelines has been proposed.
Another widely used method is the fibre optic method, wherein fibre optic sensors are installed along the exterior of the pipeline. They can be installed as distributed or point sensors to extensively detect the physical and chemical properties of hydrocarbon spillage along the pipelines. Further, sensors, ultrasonic flowmeters and bulk meters are installed at all points of the distribution chain for leak detection. Tethered acoustic leak and air pocket inspection technology also helps detect leakages.
Meanwhile, fluorescence methods for the detection of hydrocarbon spills employ light sources of a specific wavelength to excite the molecules in the targeted substance to a higher energy level. The detection of a spill is based on the proportionality between the amount of hydrocarbon fluid discharged and the rate of light emitted at a different wavelength, which can then be picked to detect the occurrence of hydrocarbon spillage.
Several other techniques have also been adopted by Indian cities to detect pipeline leakages. The Kerala Water Authority (KWA) has adopted the Sahara Drag chute and Smart Ball leak detection technologies for easier and more effective detection of leakages. Under this, the equipment is tethered to the surface while the sensor flows along with the water. A certain velocity of water has to be maintained for the functioning of the equipment, which consists of a small drag chute that enables the movement of the sensor. KWA also uses SmartBall technology to detect leakages in the water network. The SmartBall can travel with the flow of the water for up to 12 hours, collecting information about leakages over a long stretch of pipeline in a single deployment. However, due to the condition of pipelines in the city, SmartBall cannot be used for long distance services.
Bengaluru uses WaterOn, an app that allows individual households to keep track of water usage and curb wastage for 45 days. Meanwhile, the Gurugram Metropolitan Development Authority has implemented a centralised integrated water management system to identify the demand for potable water, check illegal supply and analyse incremental supply.
Leakage localisation is an essential component of pipeline monitoring as it speeds up the repair process. Mobile sensor nodes with built-in GPS have been deployed to determine and report the geographical location of pipeline leakages. The use of mobile sensor nodes in pipeline environments is essential as it can enhance coverage and help a network recover from any failure that partitions the whole network into multiple disconnected subnetworks. However, the cost of implementation of these sensor nodes with GPS capability is extremely high.
Metering is another important aspect of a water project. The absence of water meters has been a root cause for issues such as high NRW, unchecked leakages and overflows, and unauthorised and reckless water consumption. Smart water meters enable utilities to detect leakages earlier than usual and monitor usage to aid enforcement efforts. By deploying smart water meters, unnecessary repair/replacement costs can be skipped and more savings can be generated. The city of Pune is adopting smart meters in a big way to enable early leakage detection and significantly reduce water losses. Many smart meters have also been deployed under the 24×7 water supply project in Nagpur. Pimpri Chinchwad is also looking to adopt LoRaWAN technology for smart meters, which enables the collection of real-time data over long distances and helps detect leakages. The Chennai Metropolitan Water Supply and Sewerage Board has already started installing digital water meters with automated meter reading (AMR) in commercial properties across the city. The project is being implemented under the Smart Cities Mission at an estimated cost of Rs 95 million. As of February 2020, 5,300 AMR meters had been provided to commercial properties such as hotels, industries and educational institutions.
Meanwhile, the Municipal Corporation of Greater Mumbai (MCGM) has launched a portal called MCGM GIS, which will give an overall geographical view of the city on a map and allow users to check plot reservations, and the progress of roadworks and pipelines passing through a particular area. At the same time, developers can access information about existing pipeline networks to prevent damages. GIS technology helps find the exact location of faults in pipes and is thus effective in detecting leakages. Cities such as Indore are using supervisory control and data acquisition systems to detect leakages, while Vadodara and Mumbai are using sound-based leak detection technology.
In sum
Controlling leakages is critical to reducing the NRW level of water networks. Advanced equipment and tools such as sensors, ultrasonic flowmeters and bulk meters need to be installed throughout the network to detect leakages. Leak detection is a field that continues to grow and advance with the use of both established technology and emerging methods. The performance of various pipeline leakage detection methods varies depending on the approaches, operational conditions and pipeline networks. Leak localisation and estimation of the leakage rate are both important as they facilitate spillage containment and maintenance at an early stage to avoid any serious damage to the environment.
According to a report by Frost & Sullivan, internet of things sensors, machine learning, artificial intelligence, and cloud- or edge-based data analytics platforms are strengthening the global market for smart water and wastewater leak detection systems. In order to leverage these growth prospects, leak detection solution providers should integrate their technologies and customise services to meet customer demands, and make investments in the development of smart cities and resilient infrastructure