5 minute read
Pumping for perfection
As the global need for water continues, urban water loss is an increasing challenge for water distribution networks around the world. At Grundfos, efforts to deliver smart and cost-effective solutions to ensure stable and efficient water supplies never stops. Pipes, Pumps and Valves Africa finds out more.
Clean water scarcity is a major issue in today’s world. Considering that the world’s population is expected to increase by 2 billion persons in the next 30 years, from 7.7 billion currently to 9.7 billion in 2050, a 22 to 24% increase, the strain on water systems is inevitable. Krzysztof Myslinski, IMEA development manager at Grundfos, a global leader in the supply of pumps and controls, when it comes to water distribution systems it is essential to never compromise on the quality of pumps, always using the most optimal equipment available. Speaking during a recent online conference, Myslinski said as the global need for water continued to increase, improving pumping system performance to prevent water leaks and reduce utility operating costs would increase. Using a general example of a water supply system he said optimal equipment was needed at the water intake site as well as for the transmission and distribution. “Some of the main considerations for a water supply system include that it should be capable of supply water at all the intended places with sufficient pressure heat and it should be capable of supplying the requisite amount of water at all times – even during events such as firefighting.” He said the layout of water supply systems was of critical importance as no consumer should ever be left without water, for example, when any section of the system needed maintenance or repairs. “All the distribution pipes should be preferably laid away or above the sewer lines. Water quality should not get deteriorated in these pipes.” And it should all happen while keeping the energy cost to a minimum and avoiding any or all water loss. Every year, 45 million cubic meters of drinking water are lost daily through water leakage in the distribution networks. This is enough to serve nearly 200 million people. “We have to reduce the yearly non-revenue water (NRW),” says Myslinski. NRW is water that has been produced but is lost before it reaches the customer.
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Beat the leaks
Leaking pipes and equipment are a global problem experienced in the most developed and least developed regions of the world. It remains true that one of the surest ways to reduce water loss and address cost is to use optimal quality pumps and equipment, says Myslinkski. He also advises the water network to be divided into sections as this makes it far easier to cope with problems as they arise than trying to address an entire distribution network in one go. “At the start of the network one has the main pumping station and the treatment works. There are some typical arrangements.
These pumps that supply water to the distribution system are located near the water treatment facility or potable water storage facility and will pump directly into the distribution system or transmission lines. Normally they are rated for high flows and high heads and are operational 24 hours a day,” says Myslinkski emphasizing the need for quality. By using pumps and systems specifically designed for durable use and variable flows one ensures the right balance between self-contained systems and pressure zones in the water distribution system. “Overall efficiency of your pumps and systems is highly dependent on the controls. This means controlling the entire system is of critical importance. Proven reliability lies in best quality and process control.” Compromising on quality comes at a price and one must look at delivering high standard performance. According to Myslinkski, the importance of pumps cannot be overemphasized in delivering optimal solutions. Whilst a wide range of pump types and sizes are available, using the correct pump delivers benefits such as lower costs, ease of use, safer operations and less maintenance. Using the pump correctly delivers a longer operating life. “A horizontal split case pump, for example, is very reliable but also a very simple pump design that is easy to operate and use. It offers high energy efficiency and low life-cycle costs from the easy to service split case design. The double suction minimizes axial load, extending the life of the wear rings, shaft seals and bearings. The double volute reduces radial forces and minimizes noise and vibration. Another option at pumping stations that is often used is single-stage, end-suction, close- and long-coupled pumps. These pumps offer benefits such as optimized hydraulics in housing and impeller for unimpeded liquid flow. “Housing, impeller and wear ring in different materials for improved corrosion resistance and sticking elements also add benefit, while the back pull-out design for easy dismantling for service is also worth mentioning.”
Manage the pressure
Another important element to remember is that of pressure management – especially in water supply networks, says Rajesh Sunkarineni, a product manager at Grundfos. “A lot of the infrastructure being used is old and that results in increased leaks and bursts. It is also part of the reason why it is so difficult to make systems more efficient. There is also the fact that many systems are still maintained and operated in old-fashioned ways sometimes.” He says there is a need to optimize the pressure management systems to provide more intelligence to the system itself and to control the pumps in an improved fashion. “The primary focus has to be operational efficiency. The overall efficiency curve for a pump system is important and pumps must be operated at the most efficient level.” He says many pumping stations are equipped with a system that starts and stop pumps and regulate the speed of the pumps, but often the operational efficiency of the pump is ignored. Improving this efficiency can allow for serious gains and benefits across the system. Sunkarineni and Myslinski maintain that improving system performance and reducing water loss requires a two-fold approach – good quality pumps selected correctly and operational efficiency. From having the correct size pump in place to the right number to operating them correctly it is all part of an ongoing process where the overall monitoring and maintenance of the system is just as important to stop loss and achieve savings.
