MATTISHALL STW - Breckland, Norfolk | Secondary Wastewater Treatment Plant

MATTISHALL STW is a wastewater treatment plant located in Etling Green, near Dereham, in the Breckland district of Norfolk, England. It serves a population of approximately 3,220 people, classifying it as a small agglomeration under UK regulatory frameworks. The plant is situated in a rural area of East Anglia, a region characterized by low-lying terrain and a temperate maritime climate. The plant provides secondary treatment, which is the standard biological treatment stage required for inland freshwater discharges under the Urban Waste Water Treatment Directive (91/271/EEC). With a designed capacity of 3,256 cubic meters per day and an average daily discharge of 716.88 cubic meters, the plant operates well within its capacity. As a small agglomeration, it is subject to monitoring and reporting requirements under the Environment Agency's permitting regime. The treated effluent from MATTISHALL STW is discharged into local watercourses that ultimately drain into the River Wensum, a chalk river of high ecological importance. The Wensum flows through Norfolk and joins the River Yare before reaching the North Sea at Great Yarmouth. The plant plays a key role in protecting the water quality of these sensitive river systems, which support diverse aquatic life including salmonid fish and rare invertebrates.

The treated effluent from MATTISHALL STW enters local tributaries that feed into the River Wensum, a designated chalk stream known for its rich biodiversity. The Wensum flows eastward to join the River Yare, which discharges into the North Sea via Breydon Water estuary. This catchment supports species such as brown trout, water voles, and various dragonflies. The plant's secondary treatment helps maintain water quality standards in this ecologically sensitive river system, which is part of the Norfolk Broads area.