In this paper, we present a mathematical model for a continuous, integrated advanced oxidation process consisting of single-component adsorption, UV photocatalytic mineralization, and draft tube transport. The model is developed and employed as part of a strategy to determine optimal values of selected process design parameters and to identify suitable process operating conditions that may lead to an overall robust performance. An optimization-based algorithm is presented and applied to the design of a water purification system utilizing a composite titanium dioxide/activated carbon photocatalyst adsorbent immobilized on a silica substrate for the degradation of reactive red (RR) dye. 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.