Grantham STW Wastewater Treatment Plant, South Kesteven, Lincolnshire

Grantham STW is a wastewater treatment plant located in Barkston, near Grantham, in the South Kesteven district of Lincolnshire, England. It serves a population of around 61,033, placing it in the medium-to-large agglomeration category under UK regulations. As a UK wastewater facility, Grantham STW is regulated under the Urban Waste Water Treatment (England and Wales) Regulations, which transpose the EU Urban Waste Water Treatment Directive. For agglomerations of this size, secondary treatment is typically required, with additional nutrient removal if discharging into sensitive areas. It meets the standards expected for its population tier. The treated effluent from Grantham STW is discharged into local watercourses that ultimately drain into the North Sea via the River Witham or the River Trent catchment. The plant plays a key role in protecting the water quality of these rivers and the downstream Humber Estuary, which supports diverse aquatic life and is an important ecological area.

Grantham STW discharges into the River Witham catchment, which flows through Lincolnshire into the Wash, a large estuary and bay on the North Sea coast. The Wash supports important bird populations and is a designated site for nature conservation. The plant's operations help maintain water quality in this sensitive downstream environment, reducing nutrient loads that could contribute to eutrophication in the estuary.