Melbourne Water Corporation’s Eastern Treatment Plant (ETP) processes 40 percent of Melbourne’s wastewater each day and serves 1.6 million people. It is the second-largest wastewater treatment plant in Australia and the largest activated sludge plant in the Southern Hemisphere.
The ETP produced chlorinated secondary effluent, which was discharged via a 56-km pipeline into the ocean. The discharge point at Boags Rocks was through a nearshore outfall, and the discharge was apparent to beach users and surfers.