Water & Wastewater Treatment Magazine
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www.wwtonline.co.uk | WWT | XXXX 20XX | 21 The Works W hen the presence of pesticides caused Winterton Water Treatment Works to fail Drinking Water Inspectorate standards aer routine borehole tests in November 2012, it was shut down immediately, with the water run to waste and Anglian Water forced to put an alternative supply into place. By the time it had reopened in April this year, the treatment plant – which supplies 9.5 megalitres of drinking water a day to the 15,500 people of Scunthorpe while acting as a booster for nearby Thealby – had been mothballed for five- and-a-half years. Anglian's task had been complicated by the fact that one of the pesticides found at elevated levels was clopyralid, a herbicide used for control of broadleaf www.wwtonline.co.uk | WWT | JULY 2018 | 21 weeds that has been banned in several US states due to its ability to linger in manure and compost, damaging plants years aer its initial application. Bentazone, which had also been found to exceed levels during the borehole testing, was being treated effectively at the works, but clopyralid has a molecular structure that makes it far more challenging. It is extremely difficult to remove using traditional treatment methods like granular activated carbon and ozone and, as such, could not be tackled at Winterton. Anglian's initial proposal, approved by the DWI, had been to build a 10-kilometre pipeline from Winterton WTW to Elsham WTW, which supplies much of the drinking water for northern Lincolnshire, to allow the water to be blended and returned. The estimated cost for the pipeline was £5 million. When Anglian brought in a catchment management team three years ago, though, they realised there was a better way of overcoming the challenge. As the water continued to be sampled, the levels of the two pesticides came down, indicating that the original source was likely to have been a spill or a drip from a farmyard that had made its way through the aquifer and into the groundwater source. The Anglian Water catchment management team suggested working with the farmers to put systems in place that would provide sustainable solutions for both parties and negate the need for the pipeline. GOAL 3 DRINKING WATER QUALITY A er Winterton Water Treatment Works spent almost six years out of operation due to pesticide problems, Anglian Water found the way forward by working with local farmers on a catchment management solution that resolved water quality issues at a fraction of the cost of their original plans By Robin Hackett Seeking solutions at source Farmers received advice on the safe handling of pesticides