Pressure group

Water companies struggling to keep to leakage reduction targets set by industry regulators could soon be assisted by a new pressure controlling system developed in the UK.

Southampton-based i20 Water has designed an electronic system featuring a self-learning algorithm that allows it to regulate the pressure of a water network. The company claims its technique, due for launch later this year, is the cheapest and fastest way to reduce leakage, compared with existing methods, which involve digging up the road to fix leaks or to replace pipes.

'Both methods are very expensive and also a lot of leaks are very small, so it is not cost-effective to dig up the road and fix these little leaks. Really the only way of tackling that leakage is by managing the pressure better, which is what our system does,' said i20 Water's managing director Adam Kingdon.

The company's business plan is to achieve an average of 11 per cent reduction in leakage, depending on factors such as the size of leakage and existing water pressures, but it says that recent trials have exceeded this goal.

'We have been trialling [the system] with one major water company since January on part of its network and we have reduced the leakage on that bit by over 25 per cent,' claimed Kingdon.

This result is significant when considering how water companies in England and Wales, according to Kingdon, lose 3.6 billion litres of water a day — the equivalent of 149 litres per property, per day.

At the moment, pressure in the water network varies greatly — from very low in the day and early evening when many people are using water, to very high at night when no-one is using water. The new technology aims to smooth the pressure out and at the same time reduce the average pressure in the pipe and reduce leakage by constantly controlling the pressure to keep it at just the right level depending on the area's needs.

For the technology to work, one part of the company's system is installed at the entrance (or inlet) to a distribution network area (a zone that would typically have up to 2,000 houses) and another component is fitted at what the company refers to as the 'critical point' — that is the point in the network that is furthest away from the inlet, at the highest ground level and where pressure is lowest.

'At the entrance to the network you have an existing pressure reducing valve (PRV) that is at the moment fixed at a certain pressure using a big spanner. They have to have that pressure high enough so that during the middle of the day when everyone is using loads of water, it does not fall below the legal minimum pressure of 15m, particularly at the critical point,' said Kingdon. Without the new technology, Kingdon said companies find that they go below the stipulated minimum pressure several times each day, resulting in an unstable service to customers.

Thus at the inlet, a pilot valve is attached to the PRV, and this is connected to a stainless-steel encased electronic controller that measures the flow rate into the PRV and contains a self-learning algorithm that electronically regulates the pressure.

At the critical point, a monitoring device comprising a pressure transducer measures the pressure at least once every minute (some water companies measure the pressure every 15 minutes on average) and the flow rates, and stores this data.

'Every day, the controller PRV side and the monitor at the critical point connect to our server using GPRS and download the day's data. Our software calculates a new algorithm based on the data and it automatically downloads a new algorithm to the controller. So the longer it is installed, the more data it has and the better the algorithm,' said Kingdon. The information can then be made available to water companies either through i20 Water's website or directly through its own management information system.

A lack of power sources at the PRV means that the most challenging aspect of the project for Kingdon was to make a system with very low power consumption.

'The system is powered by a battery with a five-year life. Most of the time the device is switched off and a little part of the device monitors the flow rates. If it goes outside certain parameters it wakes up the rest of the device and calculates what the new pressure should be. If the pressure does drop below a fixed level or if there is a burst, it would send an alarm to the server and we alert the company,' he said.