What's this project all about?

The Rosny Sewage Treatment Plant in Hobart received a major upgrade from 2023 to 2025, including a new ultraviolet (UV) disinfection system to improve environmental outcomes for the Derwent River.

Sewage treatment is a series of processes that create barriers which prevent and lower the risks of contamination when wastewater is released. Using UV is a modern and effective means of disinfection, allowing us to reduce the amount of chlorine used in the sewage treatment process. This will improve the quality of the treated effluent released into the environment and aligns with TasWater’s commitments to the Environment Protection Authority and our customers.

As part of these works, TasWater undertook an upgrade of site stormwater and drainage systems and also installed a new additional cloth filter. This is another barrier that forms part of the treatment process and filters microscopic particles from the effluent.

Construction took place during 2024 and 2025, following early demolition works in the second half of 2023 to create room within the plant for this new infrastructure.