A Draft Tube Spouted Fluidized Bed Reactor (DTSFB) has two defining characteristics (1) the draft tube (transport line) where the particles and fluid are removed from the bottom of the annular bed and transported upwards in either a dilute or dense phase mixture and (2) the annular bed that surrounds the draft tube where the particles move downward as a moving packed bed. The type 2 DTSFB has several advantages over pervious designs because it allows for independent control over the solid circulation and the flow through the annulus and the draft tube. The ability for a type 2 DTSFB to remove material at a determined rate from the annular reactor for regeneration in another isolated location allows it to be used for a photocatalyzed water purification process. Traditionally photocatalysts have either been used in slurry or in a packed column to remove organics compounds from water. The competing characteristics of these designs are catalyst surface area and exposure time to the ultraviolet light. The DTSFB overcomes these by providing a large surface area of catalyst particles and by recycling them through an ultraviolet light reactor to regenerate them. The DTSFB system offers continual adsorption and mineralization of an organic contaminant, however, the difficulty is in being able to find the optimal range of operating conditions which lead to an overall robust performance and understanding what penalties there would be if this system is not being run at these optimal operating conditions. In this work we present a mathematical model for a continuous, integrated water treatment system consisting of a photocatalytic process (UV chamber), an adsorption process (moving packed bed), and draft tube transport. This model is employed as part of a strategy to determine the optimal values of selected process design parameters and identify suitable process operating conditions that may lead to an overall robust performance based on an objective function of either utility cost or bed height. The optimization-based algorithm is presented and applied to the design of a water purification system utilizing a titanium dioxide photocatalyst immobilized on an activated carbon substrate/adsorbent for the degradation of various organic materials. A sensitivity analysis is performed to identify qualitative trends implicit in the proposed mathematical model and to measure the robustness of the resulting design over a range of process operating conditions. The optimal operating conditions and design parameters are discussed as to how they apply to the operating system and the range of these values. The overall robustness and system sensitivity to operating conditions is reported and applied to the real operation of the type 2 DTSFB for the application of water purification.