Challenges for management of treated sewage in NSW Southern Highlands rivers : drinking water catchment, World Heritage Area and platypus habitat

This study looked at the impact of four STPs located within the Southern Highlands to identify if environmental regulation was adequate in minimising pollution of waterways of high value. The Southern Highlands, Nattai and Wingecarribee Rivers are major tributaries to drinking water catchment, and Greater Blue Mountains World Heritage Area (Nattai River) as well as being platypus habitat. Results show elevated levels of nitrogen and phosphorus as well as heavy metals such as copper, zinc, iron and aluminium. The NSW EPA are responsible for enforcing discharge limits however, limits for heavy metals are not included in these licences and nitrogen and phosphorus limits significantly exceed ANZECC guidelines for environmental protection. Furthermore, a comparison of discharge limits between Southern Highland STPs and Western Sydney STPs revealed significant discrepancies as Western Sydney STP had tighter limits and included heavy metals despite not discharging into environments of high value. This study highlights the need for improved EPLs that reflect and state clear environmental goals for receiving water ways to ensure adequate environmental protection.