St Arnaud Wastewater Treatment Plant, Victoria | Australia

St Arnaud wastewater treatment plant is located on Cemetery Road in St Arnaud East, Victoria, Australia. It serves the small rural community of St Arnaud, with a population of around 2,585 people, and is operated as part of the municipal wastewater infrastructure managed by the Shire of Northern Grampians. The plant provides secondary treatment, which is the standard level required for inland communities under Australian wastewater regulations. The plant's discharge volume of approximately 669 megalitres per year indicates it is sized appropriately for its service population. Australian treatment plants of this scale typically operate under state-issued environmental protection licenses that set discharge limits to protect receiving waters. The treated effluent is discharged into the local catchment, which ultimately drains into the Murray-Darling Basin, Australia's largest and most significant river system. This basin supports extensive agricultural activity and provides habitat for diverse aquatic species, making proper wastewater treatment essential for maintaining downstream water quality and ecosystem health.

The plant discharges into the local catchment of the Avoca River, a tributary of the Murray-Darling Basin. The basin drains into the Southern Ocean via the Murray Mouth in South Australia. The region experiences a semi-arid climate with variable rainfall, and the river systems support important wetlands and migratory bird habitats. Effective nutrient removal from wastewater is critical to prevent algal blooms and maintain water quality for irrigation and ecological health downstream.