Persistent odour complaints can quickly erode public confidence in wastewater networks. In Duncraig, Western Australia, a sewer pressure main extension has been delivered to redirect discharge away from residential frontages and restore community amenity.
Water Corporation engaged Saltire to modify the existing design and construct a 288-metre DN355 PN20 HSCR PE100 pipeline, extending the pressure main to an existing gravity section at a more suitable discharge location. The sewer pressure main extension was designed to remove the odour source while maintaining network integrity and operational continuity.
Rather than adopt conventional open-cut construction along residential verges, the project team reworked the design to suit trenchless installation. Horizontal directional drilling reduced excavation volumes and limited the need for driveway removals, road closures and extended traffic management.
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How did trenchless delivery minimise disruption in Duncraig?
The sewer pressure main extension required new discharge infrastructure and concrete chambers in a constrained suburban environment. By carefully locating HDD launch and receival pits, the team preserved driveway access and maintained local traffic flows throughout construction.
Works included detailed service location and survey, pit excavation, HDPE welding and installation, valve and fitting placement, pressure testing and final tie-ins to the existing pressure main. Restoration works were completed following commissioning.
The program was delivered within 25 working days. For residents who had experienced ongoing odour issues, the outcome was both operational and perceptible.
Why is sewer discharge location critical to community outcomes?
Pressure main and gravity sewer interfaces can create localised odour risks, particularly where discharge points sit close to homes. Extending the main to a more appropriate gravity connection redistributed flows and removed the nuisance at its source.
The sewer pressure main extension also demonstrated how targeted infrastructure upgrades can address service issues without large-scale reconstruction. By integrating trenchless methods with revised hydraulic levels, the project balanced engineering performance with social licence considerations.
For utilities managing ageing wastewater networks in established suburbs, the Duncraig example highlights the value of adaptive design and construction sequencing. Minimising excavation, maintaining access and resolving customer complaints can occur simultaneously when delivery models are aligned with site constraints.
The completed sewer pressure main extension has eliminated the odour issue in the local area and generated positive community feedback, underscoring the importance of responsive infrastructure management in suburban settings.
Saltire will be participating in Connected by Water 2026, where industry leaders will examine practical solutions for resilient and community-focused water infrastructure.