INDUSTRY FOCUS WATER & WASTE TREATMENT SMARTER TOOLS LOWER LEAKAGE
Alick MacGillivray, senior consultant at NEL, outlines the modern measurement and network management techniques that can be applied to meet the challenges facing the water industry today
metering and network analysis. As they are connected to a modern
M
uch of the UK’s water distribution pipe network is ageing and leaking.
For water supply companies, effective network management is a must, and the industry is investing substantial sums to repair the infrastructure. Alongside these challenges, water companies must also satisfy the demands of the regulator, and must perform annual water balance calculations. The water balance is a set of calculations that compare the volume of water drawn, from sources of supply, to the demand. Water companies must also independently calculate a Service Incentive Mechanism score, which is part of the process for setting the price and the service package they must deliver. There is no single solution that can address these challenges, but there are a range of modern measurement and network management techniques that can be applied, which include smart
Smart metering and network analysis should be used in combination to achieve the
improvements necessary to meet the challenges facing the water industry today, one of which is leakage
communications network, smart meters remove the need for water company staff to physically inspect the flow meter, reducing the cost of maintenance and customer billing. They can also assist in the identification of leaks and, because they transmit a large volume of data, they allow the water company to manage their network more efficiently. However, smart meters should be augmented by smart network analysis techniques. In water networks, flow meters are
Alick MacGillivray is senior consultant at NEL, part of the TÜV SÜD Group
subject to a wide range of conditions, and potentially to electromagnetic or acoustical interference, as well as mechanical damage. To manage this, the water industry has developed analytical methods to detect when this happens, such as the use of mass balances techniques to estimate the level of leakage in systems. The development and application of data analysis tools takes this a stage further by helping to identify the individual instrumentation that is mainly responsible for the imbalance. Data validation is the most basic of these tools, which is used to assess the
THE BUILDING BLOCKS OF WATER QUALITY
ACWA Emirates, part of the ACWA Group, has been selected to design and implement the water recirculation and treatment facilities for the new LEGOLAND Water Park at Dubai Parks and Resorts. Led by main contractor ARCO General Contracting, ACWA was responsible for the design, installation and commissioning of the complete water treatment and circulation solution. This ensures hygienic recreational quality water throughout the water park and provides continuous filtration for approximately 1.4 million cubic metres of water per day. The solution comprises three plant rooms and three propulsion turbine pump stations with more than 35
water pumps, together with an array of strainers and nine regenerative media filters, Ultra-violet treatments, twin chemical dosing systems and 14 heat exchangers to ensure a constant water temperature is maintained. These ensure consistent high quality water for the water features and pools, which includes over 15 water slides, a LEGO wave pool, a Build-A-Raft-River plus a DUPLO Splash Safari play area. Water quality and water conservation are both important factors and
ACWA has specified mechanical strainers followed by special regenerative media filters which can remove particles down to one micron in size, exceeding the capability of traditional sand filters which can typically only filter down to 20 micron. At the same time no backwash is required which saves water, reduces energy consumption and means no downtime. This, together with a smaller footprint plus user friendly maintenance, makes it a suitable solution for the water park. From the filtration system, water passes through the UV treatment
system to remove any remaining pathogens and then through the 14 heat exchangers. As a final polishing step, the water is dosed with chemicals to correct the pH balance before it circulates around the park. ACWA
www.acwa.co.uk
quality of the acquired data and detect gross-errors. For example, it is possible to set upper and lower limits on measured flows and to reject data that are outside this range. Another technique is to set limits on the rate of change of measured quantities to detect spikes and other transient behaviour in the network. Often analyses are not based on
individually acquired points, but on data that has been smoothed or averaged over a period, which allows the operators to determine longer term trends in the data, assisting in demand forecasting. This technique can be taken further by the application of neural networks or generic algorithms which learn the behaviour of a metering network in order to alert operators to anomalies. The use of simple mass balance techniques to estimate the amount of leakage in networks has now been taken a stage further by Data reconciliation (DR), which identifies the flow meters most likely to be responsible for imbalances, so that water companies can focus maintenance on where it’s required most. It can also be used to determine the level of leakage in a network. The calculations are normally performed
using DR software installed as part of the water company’s data historian. It is common that the calculations are triggered during the minimum nightline period, usually on a daily basis. In this way, it can act as an early warning system for instruments that are drifting out of calibration, or the development of leaks in the trunk mains. Companies using this technique have
more confidence in their trunk main flow data, as it is continuously being checked for consistency against the rest of the network. It can also reduce OPEX due to a reduction in maintenance levels. Optimising data utilisation is an
operational imperative for water companies under environmental, regulatory and resource pressure. Failure to protect metering investments, by not complementing them with data analysis techniques, risks increased capital and operational expenditure.
NEL
www.tuvnel.com 32 SEPTEMBER 2017 | PROCESS & CONTROL
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