Government of Jersey
Bellozanne Sewage Treatment Works
Sweco supported The Government of Jersey’s Infrastructure, Housing & Environment (IHE) department in preparing a Wastewater strategy for the island. The strategy highlighted that due to outdated assets and a growing population, the existing Sewage Treatment Works (STW) at Bellozanne no longer met environmental standards, and that the only viable option in terms of meeting the current and future requirements was to replace it.
Sweco has worked with the Government of Jersey for over 20 years, and since 2014 have partnered with its Infrastructure, Housing and Environment team (previously the Department of Infrastructure) under both its Technical Consultancy Framework and the current Liquid Waste Professional Services Framework.
During this time, Sweco has developed the design of the new Bellozanne Sewage Treatment Works (STW), by supporting IHE from the earliest strategy and concept stages through to conclusion and final commissioning in December 2023.
The existing STW at Bellozanne had been operational for over 50 years and had undergone several upgrades but was failing to meet the required nitrogen standards as demand increased. The new STW will support the construction of new homes and is capable of accepting flow from the equivalent of 141,600 people which is significant growth from the current population of 102,000. It will also reduce running costs and provide better odour control, with more consistent control of nitrogen levels released into St Aubin’s Bay.
Construction itself began in 2019, with work undertaken in stages as parts of the old STW were decommissioned to make way, parts of which dated back to the 1950’s. The state-of-the-art, £67 million pound project is part of a wider £83 million pound plan, which includes planning, investigations, engineering, site services, old sludge platform , demolition, hillside removal and Clinical Waste Incinerator replacement.
Over a five year period starting in 2009, Sweco worked with IHE to develop the first Wastewater strategy for Jersey. The strategy highlighted that, due to outdated assets, and a growing population, the existing Sewage Treatment Works (STW) at Bellozanne no longer met environmental standards. The only viable option in terms of meeting the current and future requirements was to replace the existing STW.
In preparing the Waste Water Strategy (WWS), Sweco analysed and identified how Jersey collects, treats and disposes of waste water at various facilities operated by IHE.
Our work included:
- A review of the condition and performance of all the existing assets
- A review of current and future legislation and European directives
- A reassessment of the location for the sewage treatment works
- A review of the sewerage (collection) system
- A review of future population growth and location of new housing developments
- A focus on actual environmental outcomes as opposed to arbitrary limits
The replacement of the existing works had to be completed in phases to ensure continuity of service. Accommodation and enabling works to create space at the constrained site began in 2015 and continued until the start of the STW construction in February 2018.
Deputy Tom Binet, Minister for Infrastructure, said: “This state-of-the-art new facility represents a significant step forward in the way in which we manage and treat liquid waste in the island.
“It’s clear to see it’s a remarkable piece of engineering that this exceptional team has quietly got on with, ensuring Jersey has a modern sewage treatment works, fit for our current and future population.”
Having recently completed the Bridging Liquid Waste Strategy for 2023-2026 Sweco are beginning the next phase of Key Infrastructure projects with IHE. These include Strategic Storage Tanks, Rising Main Replacements, Surface Water Separation schemes and Pumping Station Upgrades. In parallel with this major programme of works, Sweco are also beginning to support I&E with the preparation of the Liquid Waste Strategy for 2026-2036 and the Long Term Capital Programme to 2050.