Optimising Water Operations
Insufficient pressure caused by high flow during peak demand can lead to customer complaints. Boosting pressure to address these issues can have a significant negative impact on leakage levels, burst frequency and energy consumption.
Insufficient pressure caused by high flow during peak demand can lead to customer complaints. Boosting pressure to address these issues can have a significant negative impact on leakage levels, burst frequency and energy consumption. Manila Water in the Philippines chose a solution that helped to not only save 580 m3/day but saved operator time.
By Andrew Burrows
Manila Water is one of many water utilities that has started using new smart network management technologies to understand pressure flow relationships and optimise the pressure of water in their distribution networks. This is helping to improve customer service, achieve environmental savings and improve the resilience of its network.
The utility provides water and wastewater services to more than 6.2 million people in the East Zone of the Philippines' capital city. The area comprises one million households, served by more than 800,000 water service connections.
Since its formation in 1997, Manila Water has spent more than USD$85 million on infrastructure improvements, which have increased water availability and improved the service levels to customers across the city.
Manila Water wanted to improve pressure control across its network to significantly reduce energy use, minimise leakage and reduce the need for manual intervention.
The region covered by Manila Water's network includes areas of high demand, which have required pumps to keep water pressure high to compensate for pressure losses. The company operates 26 pumping stations to supply water to its customers and to feed storage facilities.
Pumping all of this water requires a significant amount of energy which, combined with some of the most expensive power rates in Asia, mean that pumping costs are one of the company's biggest operating expenses.
As a result, Manila Water was keen to find a way to improve efficiency, reduce its energy use, optimise pressure across the network, reduce volumes of non-revenue water and improve customer service levels. N. Domingo Pump Station supplies a wide range of domestic and commercial customers, including hospitals, hotels, schools and colleges.
As a result, the area has very high and very variable demand for water, with flows ranging from 40 litre/second (l/s) at night, up to 175 l/s during peak demand. Pressure variations were leading to excessive wear and tear on the network, resulting in bursts and high water loss. As well as high levels of leakage, the area was failing to meet its agreed customer service levels for pressure on a daily basis.
N. Domingo Pump Station has a 54,000 m3/day MLD capacity with three 100 HP pumps, one fitted with a variable speed drive (VSD) and two with fixed speed drives. However, the pumps require manual intervention via SCADA interface to manage pressure and demand.
"We decided to pilot i2O's Pump Pressure Optimisation solution in the N. Domingo Pump Station, one of our newly rehabilitated pump stations," says Jalil B. Madueño, manager of production planning and control at Manila Water.
The i2O Pump Pressure Optimisation solution was installed at the N. Domingo Pump Station. The pump controller was housed in the programmable logic controller cabinet, and a pressure sensor was installed at the critical point in the network. Service levels had been set to a minimum of 18m and a maximum of 25m.
Prior to the installation of the system, pressure at the critical point was variable, dropping below the minimum of 18m for 12% of the time, and further dropping to 15m during peak periods. In contrast, for eight hours a day pressure was typically 5m too high.
The pump solution was configured to automatically control the VSD pump, and to switch the two fixed speed pumps on and off as required, to ensure customer service levels were consistently achieved without creating excess pressure in the network.
A primary requirement for the technology was that it could manage the complex pump set-up without compromising customer service. To ensure the system operated smoothly, 24 hours a day, the i2O solution was fully integrated with the existing SCADA system, with real-time alarms to notify the plant manager of any issues.
Continuous, automatic optimisation delivers a stable target pressure to the customer, driving out excess pressure from pressure managed zones.
Minimising average and maximum pressures reduces leakage and burst frequency, and associated costs for operational tasks, such as repairs and leakage control. In pump-fed network zones, the automatic optimisation of pressure also directly reduces energy consumption.
Lowering pressures and calming pressure fluctuations also extends the lifetime of mains and service connections. The precise control of pressure delivers a consistent service level to the customer, further enhanced by the automatic re-adjustment of pressures in response to network events or changes in demand characteristics.
As well as Automatic Optimisation of both PRVs and pumps, these solutions also provide network visibility and intelligence, and remote control of PRVs and pumps to improve operational efficiency and customer satisfaction.
By pumping at lower pressures and with less water pumped into leaks, the N. Domingo Pumping Station now uses significantly less energy, which in turn lowers the company's operational costs. Energy use has been reduced by 283kWh per day, which equates to annual savings of £12,866 (827,000 PhP) for this one pump station.
Weekday leakage has been reduced by 14% and weekend leakage by 22%. This equates to an average of 580,000 litres per day, with an average overall saving of 18%. This has reduced costs by £7,200 (480K PhP) per annum. Burst rates have also been reduced due to lower maximum pressures and smoother control of pressure.
The company now achieves its daily customer service levels for pressure 99.8% of the time, compared to just 88% of the time before the system was installed. The total combined savings resulting from lower leakage levels and lower energy consumption are £20,066 (1.3 million PhP) per annum.
Manila Water says that using the technology, the utility has unlocked around 30% of its operators' time.
"As a result, they are able to spend more time on strategic issues, such as maintenance, checking stocks and planning," says Madueño. "The fact that we can access and view the system 24 hours a day means we can react faster and improve our response time, which in turn is further increasing our customer service levels."
He adds: "With wider deployment, we estimate that it could extend the life of our infrastructure by around five to ten years. This will not only help us safeguard our assets, but also lower capital expenditure over the longer term."
Manila Water has now identified another eight pump stations as potential sites for the systems, which the company expects to deploy in the coming months.
Andrew Burrows is a director and founding member of the Smart Networks Forum and founded i2O Water in 2005.
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