A water company is spending £1m to deal with shellfish that block its water processing plant.
Anglian Water's treatment centre in Elsham, North Lincolnshire has become affected by zebra mussels that clog the water inlet pipe from the River Ancholme.
The plant supplies much of the drinking water for northern Lincolnshire
The company is spending the money on new mussel traps to try to reduce the problem.
Kevin Fish, water supply manager for Anglian Water, said: "We extract water from the River Ancholme.
"The mussels live in the River Ancholme, and as we pump the water up here they attach themselves to the steel pipeline which causes blockages."
The facility processes 75 million litres (16.5 million gallons) of water every day. Mr Fish said they were removing six tonnes of shells from the filtration pipe each month.
The zebra mussel, Dreissena polymorpha, is a species of small freshwater shellfish.
They are thought to have arrived in the UK from southern Russia in the early 1800s, attached to the hulls of cargo ships.
They have lived in the River Ancholme for decades, but their numbers have increased rapidly over the last few years. A female mussel can produce 500,000 larvae each year.
They pose a particular problem as, unlike native mussels which burrow in to soft sand, they attach themselves to hard surfaces.
The mussels are an increasing problem across the UK, Europe and the United States.There is currently no way of containing the spread of the shellfish, although Cambridge University is testing a solution that kills the mussels using salt-based pellets.