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Water special project profile: Asset International

NCE profiles the sewerage upgrade scheme responsible for controlling pollution in the River Rea

Project description

Severn Trent Water is using the largest plastic pipe available on the market to help reduce pollution as part of a sewer improvement project in south Birmingham.

Severn Trent, in consultation with Barhale Construction has chosen Weholite, the high density polyethylene (HDPE) pipe manufactured by Asset International, to reduce the risk of pollution to the River Rea.

The £3.3M large-scale project upgrades the existing sewerage system through Cannon Hill Park near Edgbaston, Birmingham. This includes improving its resilience in storm conditions by rebuilding an overflow chamber and adding a storage tank.

This will reduce the amount of overspill into the river during storm conditions and improve the water quality of the River Rea. Five hundred metres of 3.5m diameter Weholite pipe has been laid in 47m long rows, interconnected by nine manifold sections to form a storage tank during periods of bad weather.

The end pipe will act as the primary entry point for the water. The inlet will then release the water into eight adjacent pipelines. The tank incorporates a sewage pumping station to return flows into the sewerage system.
Severn Trent’s original design considered a concrete storage chamber.

The project in figures


Value of the sewerage upgrade scheme


Amount of CO2 saved by using Weholite instead of concrete

But to save on construction time and cost the company looked for an alternative material. By using Weholite instead of concrete, the project saved 2,600 tonnes of CO2 when the overall process, including manufacture, transportation and the laying of the pipes, is considered.

This helped to contribute to Severn Trent’s carbon reduction targets. Barhale laid the pipes for Severn Trent. “Weholite pipes are lightweight and therefore easy to lay and by using plastic rather than the original concrete specification we were able to reduce the time spent on site by six months,” said Barhale site manager Roger Light.

“Also a number of health and safety issues were removed for us as there was much less requirement for heavy-lifting machinery on site for installation.”

The overall project was completed in March 2010. “Our sewerage system through Cannon Hill Park had been serving the community for many years. However, it was no longer able to cope with modern demands,” said Severn Trent Water project coordinator Wayne Ellis.

“During heavy rainstorms an overflow of sewage and rainwater spilled into the River Rea and caused pollution. We wanted to reduce these occurrences and are committed to helping clean up the river by reducing pollution from our sewers.”

Asset managing director Simon Thomas said: “We have worked successfully with Severn Trent on many projects, all of which have used our Weholite pipes.

“This project was the largest order to date for our new 3.5m diameter pipe and, in total, there were 34 sections of pipe used in the project, all of which were welded on site.

“Weholite is very versatile and particularly effective for projects of this nature because the pipes are prefabricated and lightweight, which means they can be quickly and easily laid on site.”

About Weholite

Weholite, which was first developed in Finland, exploits an advanced technology polyethylene material and is used primarily in UK water infrastructure projects.

It is lightweight, durable, easy to install, abrasion-resistant and tolerant of ground movements. It is manufactured in internal diameters from 400mm to 3,500mm.

The low pressure, high technology pipe offers the construction and water industries a low overall cost solution across a range of applications, including surface drainage, foul sewers, inter-process pipe work, culverts, attenuation tanks, ducting and outfalls.

About Asset International

Asset International manufactures a range of advanced technology polyethylene drainage pipes at its facility in Newport in South Wales.

Part of Hill & Smith Holdings, the company has exclusive UK and Ireland rights to manufacture the Weholite range of structured wall pipe.

Readers' comments (1)

  • I notice that a few letters have been published in this week's nCE along with a defence from the (ASSET?) Managing Director of the methodology used. The defence seemed to stand by there being further slinger/ signallers involved in the operation as well as the 3.5m diameter pipe being half backfilled. I, for one, find this 'defence' wholly unacceptable and embarrasing to the profession. At best it is expressed very badly- not a good advert for the professionalism of Civil Engineers; at worst it is a repeat of blatant half truths passed on to the MD by the site staff. Here I pose a few questions of my own as to the situation:
    1. Was the end section of the pipe really backfilled to half way? If so surely the gravel (see picture) would be filling the end of the pipe as well let alone the location where the new section was to fit.
    2. Even if the pipe was half backfilled this leaves a 1.75m drop with adjacent obstruction closeby. In determining whether this was a safe situation did the site management consider that a fall of 1.75m against other obstructions could not have led to injury?
    3. what measure was in place to prevent the slinger falling off the end of the pipe?
    4. is a stone strewn curved surface a suitable working area.

    I do not work for the HSE so I could not recall off the top of my head how many regulations are being breached here, but I would be surprised if it didn't cover most ACTs we hold dear in construction to ensure our safety.

    Even with a satisfactory answer to each of these, which I doubt will be forthcoming, surely nCE editors have a duty not to put the profession in such a dim light. If that photo had come accros my desk to use in publicity I would have kindly reminded the proposer that he needs to go back to the class-room and then instigated a full investigation.

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