The project include two new pumping stations, a new 5km pipeline and a host of improvements at the village sewage works.
Landscaping will include re-seeding and planting new trees to replace some none-native cypress trees which had to be removed to allow work at Langwathby sewage works.
United Utilities project manager Simon Povey said the new equipment means the company can shut down two small village sewage works at Skirwith and Winskill, instead, their waste water will be pumped to Langwathby treatment works where it will be treated to even higher standards.
"The River Eden and its tributary Briggle Beck are special areas of conservation and the water in both will now be better than ever. That’s got to be good news for the wildlife and anyone who loves using or visiting the river," Povey said.
"Our treatment works have always done a good job for their local communities but this project means we can meet increasingly tough environmental standards in future."
