Water & Wastewater Treatment

WWT April 19

Water & Wastewater Treatment Magazine

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Page 12 of 47

www.wwtonline.co.uk | WWT | XXXX 20XX | 13 The Works T he dangers that lead pipes can pose to human health have been known about for decades – they have been banned for use in new homes since 1969 – so it is a curious reflection that on the 50th anniversary of this ban coming into force, they are still posing a problem for our drinking water. Lead communication pipes, which connect to the mains in the street and are the water company's responsibility, and supply pipes, which run within the boundary of a property and are the householder's responsibility, are both www.wwtonline.co.uk | WWT | APRIL 2019 | 13 still present in significant quantities, while lead plumbing and fittings within houses also remain in many buildings. Each of these categories of pipe can cause water quality failures and health problems; while water companies are using techniques such as orthophosphate dosing or pH correction at the treatment stage to reduce the risk, it is acknowledged that replacement is the only long-term solution for ensuring a lead-free network and eliminating the problem. So how long will it take to remove all the lead pipes, and could we still be talking about the issue in another 50 years' time? Identification One of the primary problems faced by water companies addressing the issue is knowing how many lead pipes are out there in the network, and where they are. Of 28 million homes in the UK, 18.5 million of these were built before 1970. It is estimated that around a third of these (6.1 million) may still have some element of lead pipework, either in their supply or communication pipes or as plumbing in the houses. The age of housing in an area, and water quality testing data, gives a picture of which zones in a supply area are high, medium or low risk; this information is then typically used to inform where orthophosphate dosing is required to meet quality standards, and where to focus pipe replacement programmes. But while this approach works at an area level Lead pipes represent a proven risk to water quality and people's health – but 50 years a er they were banned for new use, hundreds of thousands of pipes are still in place. What will it take to finally get all of them removed? By James Brockett Taking the Lead

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