Water Technology was commissioned by Hatch SMEC JV on behalf of Adelaide Aqua to develop and validate the final design of the outfall diffuser of the Adelaide Desalination Project. The primary objectives of the analysis and modelling were to demonstrate initial dilution of the saline concentrate discharge equivalent to 50:1, and rapid dispersion of the saline concentrate into the surrounding seawater.
Full three-dimensional mid-field modelling was undertaken to simulate the performance of the outfall diffuser, it is considered that the mid-field model is capable of providing a realistic description of the water level variations and currents near the outfall diffuser. The three-dimensional midfield model was used to assess the outfall performance for a range of operating conditions and receiving water scenarios. Sensitivity tests were carried out to assess the effect of the loss of two duckbill valves on the outfall diffuser ports, assess the likely effects of modifying the outfall source description to include entrainment of water from lower layers and assess the dilution performance of the outfall with a different alignment.