A COMPANY is using ice to slice through sediment in pipes used to supply water to homes in the North East.
Northumbrian Water is investing £66m to clean 400 kilometres of trunk water mains, which are large pipes ranging between 12 and 49 inches in diameter.
They transport water around the region’s 10,000-mile network, and smaller diameter pipes feed off trunk water mains to supply homes and businesses across the region.
Over time, harmless sediment can build up and stick to the inside walls of trunk water mains. When it is disturbed this sediment can cause discoloured water.
Graham Neave, Northumbrian Water’s operations director, said that the company was currently trialling the use of ice to clean trunk mains in what is the most comprehensive operation of its type to be carried out in the UK.
He said: “Using ice is much quicker as we don’t have to empty the section of pipe we are cleaning, and refill it, as with other cleaning methods. The holes we dig to access water pipes, to enable the cleaning, are much smaller, resulting in less disruption to customers.
“It usually takes up to three weeks to clean a two-kilometre section of pipe using pressure jetting, but it takes just a few hours to clean the same amount of pipe using ice.
“As well as being more cost effective, the process also uses less water than other types of cleaning, so it is more environmentally friendly.”
A section of pipe is isolated by turning off valves at each end of the length of main to be cleaned.
Water is emptied out to make room for slushy ice which is injected into the pipe. The valves are then reopened enabling the water to start flowing again.
The pressure of water on either side of the slush compacts the ice and it scrapes the sediment off the pipe walls. The dirty ice is then flushed from the water main and the water is sampled and put back into supply.
The trial has involved inserting 25,000 litres of ice into the network, at minus seven degrees, to clean a two kilometre section of pipe between Pegswood, near Morpeth, and Ashington.
“We are very pleased with the results of the trial, and this will hopefully revolutionise the way we clean our trunk water mains in the future,” said Mr Neave.
The first phase of mains cleaning work began in 2007 and has seen the cleaning of 100 miles of pipe in South East Northumberland, North Tyneside and the north of Newcastle.
The second phase, which is under way and due to be completed early in 2015, will involve cleaning 135 miles of water main in parts of the lower Tyne Valley, Newcastle, North Tyneside and Gateshead.
The majority of cleaning work carried out by Northumbrian Water, so far, has been done by using pressure jetting.
A section of pipe is isolated, emptied and cleaned by a machine that travels through the pipe and sprays high-pressure jets of water on the inside pipe walls, removing sediment. The pipe is then flushed, disinfected, re-filled and put back into service after a range of water quality samples are taken.
Northumbrian Water is currently cleaning trunk water mains in the Newburn, Lemington and Scotswood areas of Newcastle and will soon begin on 13 miles pipe between Newburn Bridge and Gateshead.
This will hopefully revolutionise the way we clean our trunk water mains in the future