Could ice pigs solve the problem of water discolouration?

Sensemaking / Could ice pigs solve the problem of water discolouration?

Little more than plugs made out of molten ice, 'ice pigs' could be the cheapest and most effective means of cleaning the water industry's pipes.

By Ian Randall / 11 Dec 2012

Little more than plugs made out of molten ice, 'ice pigs' could be the cheapest and most effective means of cleaning the water industry's pipes.

For water companies, “the biggest single complaint is discolouration”, says Joe Quarini, a Professor at the University of Bristol. Someone opens the tap, pours a glass of water, holds the glass up to the light and they can see little specks in it.” This harmless discolouration is caused by little bits of grit and dirt, which can come from the pipe system, and collect in it. Quarini has developed a highly flexible system to clean pipes (used for water and other purposes) which can be employed quickly and efficiently without the need for harsh chemicals or digging up pipework.

A plug of partially molten ice – similar in composition to an iced beverage – is placed into the pipe through a hydrant, and pushed along by regular water flow. This plug, known as an “ice pig”, scours the pipes through which it travels. The pig and the unwanted particulate material it collects can then easily be ejected further down the pipe.

As the pig is made primarily of water, it leaves no residue behind itself – and, should it get stuck, users merely need to take a quick break and wait for the pig to melt.

“Ice Pigging offers our clients an innovative, simple, low risk and highly effective technique for cleaning water distribution mains and pumped sewers”, says David Corke, a director at Aqualogy, the global company which holds the license to use ice pigging in commercial, water based applications.

Previous pigs were made of foam, and required some work to set them off and get them out again. They were also liable to get stuck, or take a wrong turn – none of which is a problem with ice. According to reports from Aqualogy’s clients, ice pigging can remove 20 times as much sediment and biofilm as can flushing, and is as effective as traditional foam pigs, minus their complications.

Water pipes are far from the only possible use for ice pigs. In fact, Quarini first envisaged the pig for cleaning pipes in the food processing industry: “The applications are limited only by your imagination,” he says. ‘Beer pigs’, for piping in pubs and breweries, are planned for the near future. Other uses might include distributing biocide within plants, in decommissioning oil rigs, and even cleaning out urinary catheters to reduce the chance of infection. - Ian Randall

Photo: Aqualogy/Water Efficiency Awards

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