Banks of high intensity ultra violet lamps have been installed in water channels at United Utilities’ sewage works in Millom as part of an £18m refurbishment.

Project manager Roger Woodcock said the plant was the first of its type in the North West and one of only a handful in the UK.

“The lamps work on the bacteria that’s present in storm water, which can overflow from the sewer system during extremely heavy rains. They mimic the effect of bright sunlight, which sadly we can’t rely on in the North West of England. It doesn’t kill them, but it stops them re-producing and without that they quickly die off,” he said.

As well as the high-tech lamps, engineers have massively cut the chances of storm water spilling into the estuary by more than doubling the pumping capacity at nearby King Street Pumping Station. Now, any water that does overflow is zapped by the lamps at the sewage works.

United Utilities bathing water manager Sarah Jenner said Barrow’s three beaches had benefitted from millions of pounds of investment in sewer systems in recent years and, although they were currently meeting minimum water quality standards, would be subject to new European bathing classifications in 2015.

“This is just the latest of a package of improvements to Barrow’s sewer systems totalling more than £60m since 2007. But sewers are only a fraction of the problem. Duddon Estuary is surrounded by land which animals graze on. During and after storms, rainfall washes pollutants off,” she said.

In 2009, the company finished a huge tank under Ramsden Square to stop sewer flooding. In 2011, work at Rampside reduced sewer overflows near Roa Island. Work is now underway to improve storm overflows at Ulverston, and a pipe in the Walney Channel to protect rare marine habitats there.