In 2014, following an extended drought, Urban Water Solutions was commissioned by Melbourne Water to update the Melbourne Sewage Transfer Model to reflect significant changes in the system:  the return to “normal” rainfall patterns and the resultant soil saturation and lifting of water restrictions had led to increased flows in the system, particularly at the wastewater treatment plants, and a disproportionately large increase in BOD and TKN loads had been observed at the wastewater treatment plants since 2011.

The key tasks of the project were to:

• update the Melbourne Sewage Transfer Model to current development and loadings
• establish a robust platform to provide understanding of the increased pollutant loads and the wastewater treatments
• compare the current 2014 modelled and observed pollutant loads at the wastewater treatment plants;
• identify the sector(s) where the most significant changes in BOD and TKN loads had occurred; and
• verify the model for current flows and pollutant loads.