CHELLINGTON STW - Harrold, Bedfordshire | Secondary Wastewater Treatment Plant

CHELLINGTON STW is a municipal wastewater treatment plant located near Harrold in Bedfordshire, England. The facility serves a population of approximately 2,407 and is situated within the rural landscape of the Great Ouse catchment area. As a secondary treatment plant, it provides biological treatment to reduce organic matter and suspended solids before discharge. The plant operates under the UK's implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. With a designed capacity of 2,800 m³/day and an average discharge volume of 535.88 m³/day, the plant operates well below its capacity, indicating potential for future growth or seasonal variations. The treated effluent is discharged into local watercourses that ultimately feed into the River Great Ouse, which flows through the Fens and into The Wash, an ecologically important estuary. The plant plays a key role in protecting the water quality of the Great Ouse catchment, supporting aquatic life and downstream habitats. Its location inland and away from the coast reduces direct marine impact, but its discharge contributes to the overall nutrient load in the river system.

CHELLINGTON STW discharges treated effluent into local tributaries of the River Great Ouse, which flows eastward through the Fens and into The Wash, a large estuary on the North Sea. The Great Ouse catchment supports diverse freshwater and wetland habitats, including areas important for birdlife and fish migration. The plant's secondary treatment helps reduce organic pollution, but nutrient removal may be limited, potentially contributing to eutrophication risks in downstream sensitive waters.