The study presented here concentrates mainly on the mathematical models for the design of RBD unit. A pilot RBD plant is also studied and monitored to determine its energy consumption for different submerged heights. Correction factors for the complex drag force between the polymer ballas and wastewatercan be determined from this ptototype. In addition, the key design consideration for an optimum unit and operatingconditions is also studied to reduce the frequent shaft and bearings failuraes and power requirements.A computer program is written for the design of this system and to determine the correction factors.Hopefully, the information in this thesis will provide a more in-depth perspective on key RBD design considerations.