Water, Sewage & Effluent January-February 2017 - Page 34

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