• Field data collection programme
  • Calibrated 3D numerical model
  • Modelling outfall & contaminant plumes
  • Establishing compliance levels with EPA licence


The WTP is one of the largest sewage treatment plants in the southern hemisphere. The study involved the development of a calibrated 3D hydrodynamic model of the area under consideration with outfalls modelled as freshwater inputs. The models were used to simulate the impact and compliance of a range of contaminants including heavy metals, Total Suspended Solids (TSS), Particulate Organic Carbon (POC) and ammonia. The model was also used to explore comparative mixing zones for different years as well as to explore the efficacy of altered outlet arrangements.