Our May issue of Water Efficiency has just appeared in print and will be available digitally any day, but I want to make sure readers saw the feature on an innovative means of cleaning pipes that we ran in March/April. It makes me think of the expression, “The hair of the dog that bit me,” because it is a means of cleaning water’s residues with water—frozen water.
Basically, buildup happens due to biofilm, sediment and minerals. Flushing and pigging with various materials aren’t always effective means of removing the grit, and if a sponge or cleaning disc gets stuck in a line or lost, the pipe may need to be dug up. (Pigging, by the way, got its name because tight fitting metal discs pushed through metal oil or gas lines with a rod to remove paraffin accruing on the pipe walls made the sound of a squealing pig. It was found the pressure of whatever the pipe is transporting could also push the pig along). Lyn Corum’s article “Cleaning Pipes Made Easier—With Ice” discusses ice pigging, a safe, clean way of moving buildup out of pipes. You can watch a video about the process here, and below is an excerpt from the article.
Ice Pigging Is Invented To address the problem of stuck pigs, a professor at the University of Bristol in the United Kingdom developed ice pigging technology in 2000. By 2010, the university and Bristol Water had commercialized the technology. It was introduced in the US in 2012 when Utility Service Group obtained an exclusive, 10-year license. The technology is rather simple—it uses system pressure to push an ice slurry into a main through a hydrant or a two-inch fitting and down to the other end of the pipe and out through another hydrant or fitting. Ice pigging can clean any material pipe, says Paul Treloar, Utility Service Group (USG)’s product manager for ice pigging. He says the technology was designed for potable water mains and adapted for sewer force mains. Ice pigs cannot be used in gravity fed sewers (they need the force of pumped water to drive them forward). “Ice pigging will remove iron, manganese, and biofilm buildup as well as fats, oils, and grease, but not hard tubercules,” he says. The types of problems found in pipes vary, says Treloar. For example, where water is sourced, whether it is ground or surface, will produce different kinds of sediments and biofilm buildup in the pipe, and the types of treatment will vary. “If you don’t use Chlorine, there could be biofilm problems,” he says. Treloar says the traditional metal pigging requires cutting pipes open to get the pigs in if pigging launch stations have not been installed. Cutting pipes open can create problems with contamination, he says. Then, once it is closed, it should be disinfected. Foam sponges or swabs are inserted through hydrants and also use water pressure to get pushed through, says Treloar. But they can get lost. However, ice pigs melt if they get lost and the problem disappears without further intervention, he says.
Ice Pigging Is Invented
To address the problem of stuck pigs, a professor at the University of Bristol in the United Kingdom developed ice pigging technology in 2000. By 2010, the university and Bristol Water had commercialized the technology. It was introduced in the US in 2012 when Utility Service Group obtained an exclusive, 10-year license.The technology is rather simple—it uses system pressure to push an ice slurry into a main through a hydrant or a two-inch fitting and down to the other end of the pipe and out through another hydrant or fitting.
Ice pigging can clean any material pipe, says Paul Treloar, Utility Service Group (USG)’s product manager for ice pigging. He says the technology was designed for potable water mains and adapted for sewer force mains.
Ice pigs cannot be used in gravity fed sewers (they need the force of pumped water to drive them forward). “Ice pigging will remove iron, manganese, and biofilm buildup as well as fats, oils, and grease, but not hard tubercules,” he says.
The types of problems found in pipes vary, says Treloar. For example, where water is sourced, whether it is ground or surface, will produce different kinds of sediments and biofilm buildup in the pipe, and the types of treatment will vary. “If you don’t use Chlorine, there could be biofilm problems,” he says.
Treloar says the traditional metal pigging requires cutting pipes open to get the pigs in if pigging launch stations have not been installed. Cutting pipes open can create problems with contamination, he says. Then, once it is closed, it should be disinfected.
Foam sponges or swabs are inserted through hydrants and also use water pressure to get pushed through, says Treloar. But they can get lost. However, ice pigs melt if they get lost and the problem disappears without further intervention, he says.
