Bondi STP is one of ten coastal treatment plants operated by Sydney Water, a statutory state corporation wholly owned by New South Wales that provides water and wastewater services to more than four million people in Sydney, Illawarra, and the Blue Mountains.
A high-rate primary treatment plant, the plant originally discharge effluent from the cliff face, but public concern over the effect of this approach on the water quality of local beaches led to the construction of a deepwater ocean outfall, which was commissioned in 1991. At a maximum water depth of 63m and with a 512m diffuser zone, this now effectively disperses the effluent 2.2km out from the shore.
Treatment sees grit and waste removed before the water enters sedimentation tanks. An average daily dry weather discharge of 130 million liters of effluent is pumped to the ocean outfall. Digesters stabilize the settled material, which eventually leaves the site to be mixed with other organic matter for use as a soil conditioner in agriculture and forestry in the central west region of New South Wales. Screened waste and grit are landfilled.
After more than fifty years of operation and despite various updates over its life, parts of the facility inevitably needed renewal and modernization. In addition, advances in automation offered significant potential benefits in reliability and workforce welfare to a treatment works originally designed with a heavy reliance on manual operation.