Of this supply, 69% is provided by surface water sources such as streams and rivers, explains Neasa Revens, catchment scientist at Severn Trent.
“We have 16 major surface water works under our operation, from which the water is cleaned via a series of physical and chemical treatment processes, before being distributed to our customers.”
Alongside these practices, Severn Trent also continuously tests for up to 100 different pesticides, which have been identified as potential risks in the area, within their in-house laboratory.
“We sample weekly from the catchment streams and rivers during high-risk times, and also have a rigorous programme of testing at the treatment works,” explains Neasa.
Granular activated carbon (GAC) is used to absorb and remove any remaining pesticides after earlier treatment, and improves taste and odour before the final cleaning step.
“GAC regeneration is a significant cost for us in support of pesticide removal. For some products, such as metaldehyde, there are no cost-effective treatment options currently available.”
With so many external variables such as power prices and tighter environmental regulations, a wider approach was inevitable.
“To ensure we continue to offer a sustainable service and good value to our customers, we have diverted our focus away from further investment in expensive water treatment, into prevention at source.”
Severn Trent started catchment management ten years ago, and has developed this significantly over the past 18 months.
“Recent investment has allowed us to launch the ‘Farmers as Producers of Clean Water’ scheme in which farmers are rewarded for keeping metaldehyde out of their local water courses.
“It’s helped us all to understand where our water comes from a bit better.”
One particular area stands out for its catchment work successes.
Three years ago, an engagement project was launched to encourage the use of ferric phosphate in Staunton Harold, on the Derbyshire/ Leicestershire border. Since this work began, there have been no exceedances at the local Severn Trent treatment works for metaldehyde.
“Staunton Harold has been a huge accomplishment and demonstrates that working with farmers to produce clean water works.
“Through these schemes we can support and work with farmers to take more responsibility for their parts of the river.
“We can provide advice, support and training which encourages ‘best practice’ and allows the farmer to go above and beyond good agricultural practice, which in turn will help to keep a range of crop protection products on the market.”