Ice making capacity in the UK— the territory with the highest output— is now 125 tonnes of ice per week.
Suez
Going large: ice pigging developments mean that the technology can now clean pipes up to 700mm in diameter.
diameter. This is only possible with the use of vast quantities of ice slurry, with a number of UK water companies requesting ice loads of 35 000 litres in a single operation.
Ice making capacity in the UK— the territory with the highest output— is now 125 tonnes of ice per week; a major increase on the initial capacity of 35 tonnes per week when the process was first introduced. This scaling up has been enabled by the use of new methods of ice slurry production, since ice slurry has a shelf life and can only be made within 24 hours of the planned operation.
Ever since the original ice delivery truck was put on the road in 2009, many improvements to the design and function of ice delivery equipment have occurred. Despite greater control over ice quality, mechanisms to rejuvenate older ice have been introduced, which tends to form larger ice crystals as it ages.
Another major development in ice delivery equipment has been a reduction in the cost to roll out the service. Quoted prices are now on average 21 % lower than in 2010, despite inflation, thanks to cost reductions introduced with the scaling up of the equipment and teams required to deliver the specialist service.
Case studies
Northumbrian Water and Affinity Water are two UK water companies that have used the technology extensively and over a number of years. The commonality between these two companies is that before adopting the process, both had a recognised need to control sediments within their pipes.
Northumbrian Water used ice pigging instead of an invasive alternative process to reduce pipe interruptions from a few weeks to a few hours. Several benefits were realised from the process. For Northumbrian, there was a significant reduction in disruption to road traffic compared with invasive techniques of pipe cleaning where major enabling works are required, and minimal interruptions to water supply, as most ice cleaning operations were performed in a four-hour window period during the night.
Another example is Yarra Valley Water in Melbourne, Australia— one of the first to use ice pigging and for some time the largest user of the technology in the world, cleaning 400km of drinking water pipe each year. The utility recently published a detailed‘ before and after’ study showing the effect on water quality complaints after 12 months of ice pigging, entitled“ The Performance of Ice Pigging”. The study concluded that ice pigging caused a significant reduction in water quality customer complaints.
In the UK, one company who has not yet published results but report similar benefits showing water quality complaint reductions of 18 % year-on-year, and 40 % over three years. Another UK company reports a 77 % reduction in complaints following a threemonth project to clean strategic mains. The benefits of technologies like ice pigging in the wider context of a developing water industry with ever-increasing consumer expectations can only be appreciated after some years.
The future
Ice pigging was initially launched as a commercial service to the water industry. Many other applications for the core solution have been tabled since the technology was patented more than 10 years ago. For example, the food industry has strong potential for the application of ice pigging as a way of improving processing efficiency. Within the factories of large food producers, where multiple products with different varieties and flavours are produced, lost product at the point of product changeover can often have high value, create high volumes of effluent, and use high volumes of water when cleared from pipes. Ice pigging offers the potential to save much of this previously lost product and in the process reduce water consumption and effluent
32 Water Sewage & Effluent January / February 2017