Overview
Portsmouth and Havant STW serves 367,030 people in Portsmouth, England. The plant discharges treated wastewater into the Solent, a strait separating the Isle of Wight from mainland Britain.
Portsmouth and Havant STW is a major wastewater treatment facility serving the city of Portsmouth and the Havant area on the south coast of England. With a population equivalent of 367,030, it ranks as a large agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD), which requires advanced treatment for discharges into sensitive coastal waters. The plant is located at Ferry Road, Eastney, near the eastern entrance to Portsmouth Harbour. As a large-scale coastal treatment plant, Portsmouth and Havant STW is expected to provide secondary treatment as a minimum, with tertiary treatment likely given the sensitivity of the receiving waters. The plant's designed capacity is 1.00 (likely in cubic meters per second or similar unit), indicating substantial infrastructure to handle the region's wastewater. The facility operates under the UK's environmental regulatory framework, which transposes the EU UWWTD requirements into national law, with permits issued by the Environment Agency. The treated effluent is discharged into the Solent, a tidal strait that connects the English Channel to the waters of the Solent and Spithead. The Solent supports diverse marine life, including seagrass beds and important fish nursery areas, and is a key migratory corridor for birds. The discharge must meet strict water quality standards to protect this ecologically sensitive coastal environment and the nearby bathing waters of Southsea and Hayling Island.
Environmental context
The plant discharges into the Solent, a tidal strait that connects the English Channel to the waters between the Isle of Wight and mainland England. The Solent is an ecologically important area, supporting seagrass meadows, mudflats, and saltmarshes that provide habitat for fish, birds, and marine invertebrates. It is also a designated shellfish water and supports recreational activities such as sailing and bathing. The discharge must comply with stringent nutrient and pathogen limits to prevent eutrophication and protect public health in the coastal zone.
Frequently asked questions
The plant is located at Ferry Road, Eastney, Portsmouth, England, PO4 9RJ, near the eastern entrance to Portsmouth Harbour on the south coast of the United Kingdom.
The plant serves a population equivalent of 367,030, covering the city of Portsmouth and the Havant area.
The treated effluent is discharged into the Solent, a tidal strait that connects the English Channel to the waters between the Isle of Wight and mainland England.
As a large coastal treatment plant in the UK, it operates under the Urban Waste Water Treatment Directive (UWWTD) transposed into UK law, with permits issued by the Environment Agency. The plant must meet secondary treatment standards as a minimum, with likely tertiary treatment due to the sensitivity of the Solent.
For a coastal agglomeration of this size, the UWWTD requires secondary biological treatment, and often tertiary treatment (e. g. , nutrient removal, disinfection) is applied to protect sensitive marine environments like the Solent.
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