A Rotamix process mixing system was successfully retrofitted into an existing 17.5 metre diameter anaerobic digester at the Maroochy Sewage Treatment Plant in QLD, Australia. The Rotamix package was supplied to the Maroochy Alliance Joint Venture by Pump Systems Ltd after providing detailed CFD (Computational Fluid Dynamics) simulations of the proposed system. All Rotamix designs are supported by CFD analysis, either by standard modeled geometries, or by using customised models that are individualised to meet specific application parameters on a consultation basis.