Overview
St Marys A is an operational wastewater treatment plant in Sydney, New South Wales, Australia, serving a population of 118,662. It operates under Australia's national water quality management framework.
St Marys A is a wastewater treatment plant located in the Sydney suburb of St Marys, New South Wales, Australia. The plant serves a population of 118,662 and is part of the region's municipal wastewater infrastructure, managed under the regulatory oversight of the New South Wales Environment Protection Authority (EPA). As a large agglomeration serving over 100,000 people, the plant is expected to meet stringent treatment standards under the Australian Guidelines for Water Recycling and the National Water Quality Management Strategy. Plants of this scale typically employ secondary or tertiary treatment to protect receiving waters. The plant discharges treated effluent into the local catchment, which ultimately drains into the Hawkesbury-Nepean River system. This river system flows into the Tasman Sea, supporting diverse aquatic ecosystems and providing water for agricultural and recreational uses downstream.
Environmental context
The plant's treated effluent enters the Hawkesbury-Nepean River catchment, a major river system in New South Wales that flows into the Tasman Sea. This watershed supports a range of aquatic habitats, including wetlands and estuarine environments, and is important for regional biodiversity. The river system also supplies water for irrigation and drinking water downstream, making nutrient and pathogen removal critical for environmental and public health.
Frequently asked questions
St Marys A is located on Links Road in Dunheved, St Marys, Sydney, New South Wales, Australia, within the Penrith City Council area.
The plant serves a population of 118,662, classifying it as a large agglomeration under Australian wastewater management guidelines.
Treated effluent from St Marys A is discharged into the local catchment, which flows into the Hawkesbury-Nepean River system and eventually reaches the Tasman Sea.
The plant operates under the National Water Quality Management Strategy and is regulated by the New South Wales Environment Protection Authority, which sets discharge limits to protect water quality.
For large agglomerations in Australia, secondary treatment is the minimum standard, with many plants employing tertiary treatment to reduce nutrients and pathogens before discharge into sensitive catchments.
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