Sydney Starts the Final Stage of Its Coastal Sewer Diversion

Sydney’s eastern suburbs have been served by two very different wastewater routes. One takes sewage to the Bondi Water Resource Recovery Facility. The other has carried untreated sewage directly to the ocean at several cliffside outfalls. On November 10, the New South Wales government said construction had started on the final stage of its coastal sewer diversion, a project to bring the remaining two Diamond Bay outfalls into the treated route.

The Second Diversion Runs Through Dover Heights

The first stage dealt with the Vaucluse outfall near Parsley Bay. The second needs its own pumping station at Eastern Reserve in Dover Heights and connecting pipelines. The new equipment will intercept the flows now using the Diamond Bay outlets and transfer them to the wider Bondi network. Much of the construction will be underground, so the permanent works will be less visible than the changes they make to the wastewater route.

The pumping station and the connection have to function together. The station lifts sewage so that it can reach the receiving network, while the pipelines give the flow a continuous path to treatment. Each part can be built in stages, but the change at the shoreline occurs when the new route can carry the intercepted flows and the old discharges can cease.

What Changes at the Coast

After treatment at Bondi, effluent is discharged through an ocean outfall 2.2 kilometers offshore. The diversion therefore changes both the condition of the water being discharged and its point of discharge. Local benefits should be assessed around the former nearshore outlets, with the timing tied to commissioning and cutover. For now, the November announcement establishes the start of final-stage construction. Water-quality improvement remains an expected result of the completed diversion.