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Sewer work may spell end of contraflows

Waterflow workers Neil Douglas, left, and Dave Jennings use the new technology on a sewer in woods near Collins Bank, Knaresborough. Picture: Mike Cowling

Published 11th June 2009 within the Yorkshire Post
Written by Brian Dooks

FORGET holes in the road – Yorkshire Water is using a new technique to re-line sewers which means contractors do not have to dig disruptive trenches.

The new technology was used for the first time in Knaresborough yesterday by specialist firm Waterflow, employing remotely-controlled computers to guide a hi-tech light train through a sewer using ultra-violet rays to seal a new lining in place.

It means Yorkshire Water can maintain sewers without having to dig trenches and it is much faster and more environmentally-friendly.

As well as reducing disruption, the new method is particularly useful in areas which are difficult to reach using more traditional repair techniques.

The work in Knaresborough has also brought benefits to a group who do not have to pay for their water – a sett of badgers.

If the sewer had been renewed traditionally, the badgers would have had to move because parts of the site would have been dug up to allow work crews to reach the pipes.

Sewer pipes can date back to the Victorian times and were built to last, but many are now reaching the end of their life and need replacing or relining.

Yorkshire Water project engineer Colin Sinclair said: "Using the new method allows us to upgrade sections of the sewer network which would normally have been very difficult to reach and today's work is a great example of the benefits it can bring.

"By being able to remotely-control the ultra-violet light train while it's inside the sewer, we can get a perfect seal on the pipe without having to disrupt traffic by digging up large sections of the road."

Waterflow contracts manager Robert Nugent added: "This new technology is faster and more cost-effective than excavating and replacing old pipes.

"We hope this method of renovating old pipes and sewers will be adopted by all forward-thinking water companies such as Yorkshire Water."

Meanwhile, Yorkshire Water has also developed so-called platelet technology with Edinburgh-based partner Brinker, using small cubes of silicon to plug leaking water mains without having to dig down to the pipe.

The technique mimics the natural behaviour of platelets in the blood stream which find cuts and abrasions and help to prevent further bleeding.

Relining sewers helps to reduce damage caused by tree roots which can grow through the pipes, either blocking them underground or prompting a collapse.