Innovative water mains cleaning system developed

May Gurney has been working in partnership with South West Water (SWW) to develop innovative ways to clean large diameter water mains.

For some while, water companies and their contractors have used increased water pressure to clean smaller pipes, but the problem gets greater the larger the pipeline conveying the water - and as a result some important trunk mains are coated in manganese slime. The new, innovative cleaning system developed by May Gurney and SWW uses a variety of specially designed pigs (see pic) and swabs, according to the diameter and host material of the main, combined with specially designed pressure vessels.

Tim Read, Managing Director for May Gurney Utility Services, says: "Conventional mains cleaning, such as air scour and flushing, can do a reasonable job for small bore mains where there is sufficient pressure and flow - but with larger diameter trunk mains the effectiveness of these techniques drops off dramatically.

"It is important to clean trunk mains sufficiently to meet the client's expectations and ensure that water quality standards are met. Trunk mains and aqueducts planning is critical - the methodology we adopt is the key to its success."

Huw Parry, South West Water's Operations Performance & Support Manager said: "We're committed to giving our customers the highest quality drinking water. Water companies up and down the country have struggled with this problem, so we're delighted to be able to work with May Gurney on this solution. Our approach is innovative and leads the way for others in the water industry to follow."

Tim Read concludes: "Using methods such as pressure jetting can result in unnecessary excavations and additional cost, and our concern was that the design had to be integrated within a future DOMS strategy. The initial enabling works will alleviate the need for future intrusive working when maintenance is required, and drives down future operational costs."

After some 18 months of extended trials, four schemes totalling 80,000m have now been identified with SWW. At present, the system has been used to clean sections up to 4,000m and AC and PVC host pipe materials up to 300mm. With the design capable of up to 500mm, it is anticipated that larger diameters and longer lengths will be undertaken in the near future.

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