The global urban population is expected to nearly double to 6.4 billion by 2050. Meanwhile, the number of urban slum dwellers is projected to increase to 2 billion in the next 30 years (Global Water Partnership, 2013). In India, the number of people living in urban areas is expected to more than double to reach around 800 million by 2050. Such a significant increase is expected to pose unprecedented challenges for water management in urban India.
Many water utilities continue to struggle with providing clean drinking water to their consumers owing to the growing urban population. One of the major challenges faced by them is the high level of water losses in distribution networks.
Meeting consumer demands is difficult if a large proportion of supplied water is lost. Non-revenue water (NRW), defined as the difference between the amount of water put into the distribution system and the amount of water billed to consumers accounts for 41 per cent of the total water distributed in the country. However, it is not only water that is lost; it is also the energy used to produce and distribute that water which is wasted. Since this water yields no revenue, heavy losses make it more difficult to maintain water tariffs at a reasonable and affordable level. In fact, the current percentage of water leakage in Delhi is 45-50 per cent.
NRW is an important component of commercial water system management. It is the result of ageing networks, growing urban networks, insufficient network visibility, pipeline leakages, and improper and illegal service connections, among others.
Municipal corporations have been undertaking various measures to reduce NRW and improve efficiency. The concept of smart technologies involves sensors, instrumentation, advanced networking and specialised data management software. In this regard, technological initiatives revolve around two parameters – leakage detection and localisation for water transmission and distribution networks. Leakage detection systems enable operators to monitor, manage and localise losses throughout the pipelines of a water transmission system. They help in bringing down NRW levels and energy costs, besides reducing the consequential damages with instant mitigation strategies.
Designed for branched (tree structure) distribution networks with district metering areas, such systems help detect, alert, report and provide real-time information on leaks, bursts and other water network inefficiencies, thereby improving network performance.
GIS and demand forecast
Geographic information systems (GIS) have become a standard in planning and visualising the structural information in distributed water, district heating and cooling networks. The tight integration of GIS into the supervisory control and data acquisition (SCADA) system allows for an easy and interactive exploration of spatial data. It also helps process the information of the utility’s network. The ABB Group’s SCADA System S+ Operations offers an integrated GIS that combines real-time process data with geo-coded maps. GIS-based solutions help in establishing a proper water supply system and measuring NRW, besides ensuring control over leakages and water wastage.
Water companies have also started using artificial technologies to deal with water leakages and reduce energy wastage.
Along with reducing NRW and energy wastage, public utilities and industrial corporations are under constant pressure to reduce life cycle costs, optimise their operations and increase plant availability.
Water leakage is an important component of water losses. There are many methods of controlling leakage from urban water supply systems. However, this is quite a challenging task in developing countries, especially those with intermittent water supplies. Leakage control remains an effective tool for reducing water losses.
Specific methods have been developed for such systems, which are used in combination with other conventional methods. One such method is the pump efficiency monitoring system (PEMS). ABB’s patented PEMS provides detailed real-time information on mechanical pump efficiency using the thermodynamic measuring method. This, in turn, helps in finding the best balance between reactive and predictive maintenance and reduces the duration of unplanned shutdowns and costs. In addition, PEMS provides detailed information on pump efficiency, optimises maintenance intervals, reduces plant shutdown periods, and saves time and costs as compared to conventional methods. Further, it helps utilise investments in an optimal manner by getting the best out of the equipment.
Operators are responsible for operating the pumps efficiently within the upper and lower flow limits and with sufficient net positive suction head (NPSH). Sometimes the control system does not even provide the actual flow value or total operating hours. Usually, the control system displays the pump’s upper and lower flow limits and the NPSH, which are valid for full pump speed as plain values.
To this end, an alternative, which has been developed for optimising the number of running pumps, is pump group control solution (PumpFit). PumpFit is a control solution that enhances the usual automation of variable speed pump groups to always operate the pumps within the actual upper and lower flow limits and NPSH. It finds the optimum number of running pumps for the lowest electrical power consumption. PumpFit also calculates all actual limits depending on the pump’s actual speed and head to ensure fully automatic pump protection.
Conclusion
NRW is a good performance indicator of water utilities. High levels of NRW typically indicate a poorly managed water utility. For many cities, reducing NRW should be the first option while addressing low service coverage levels and increased demand for piped water supply. Expanding water networks without addressing water losses will only result in waste and inefficiency in the water management. In addition, a high rate of NRW is closely related to poor energy efficiency since water transported in networks is loaded with energy during the distribution and treatment processes.
To this end, technology solutions, both advanced and conventional, have assisted service providers in identifying leakages. However, the full potential of these technologies can be realised only if civic agencies deploy skilled workers on a regular basis.
Based on a presentation by Ramesh Kasinathan, Sales Director, Power Generation and Water, ABB India Limited, at the India Smart Grid Week 2018