An improvement to water quality in Lincolnshire will reportedly follow with the installation of new equipment.
Anglian Water said upgrades will be made to water recycling centres across the county.
The equipment will help to remove phosphorous from wastewater, which is found in human waste, food, soaps and detergents and can cause excess plant and algal growth in rivers.
For 2023, according to figures from the Environment Agency, Anglian Water recorded the biggest increase in raw sewage discharges of all of England’s water companies.
The company said the £45m investment would “help to protect nearby rivers”.
The BBC reported phosphorus also finds its way into watercourses from agricultural sources in addition to household waste, and the build up of algae can kill fish and other species.
Regan Harris from Anglian Water, said: “Our current environmental investment programme is one of the biggest in the sector.
“We’re really pleased that these upgrades to our water recycling centres in Lincolnshire will help to protect nearby rivers and increase our resilience to climate change, by helping us make sure the waste water is treated to an even higher standard than usual before it’s returned to the natural environment.”
