Reducing bead diameter had a significant positive impact on rCOD for both reactor types (𝐷 = 0.24 or 0.47, 𝑝 < 0.0001; Figure ) by increasing the specific interfacial surface area. It was also a significant driver for fluidized bed systems' CI when effluent methane management was absent (𝐷 = 0.11, 𝑝 < 0.05) because increasing bead diameter is expected to lead to greater O&M electricity required for fluidization. However, its impacts on other indicators were not significant relative to other technological uncertainty or decision decisions (𝑝 ∈ [0.06, 0.26]). For fluidized bed systems, all indicators were found to be sensitive to bead volume fraction in the reactor (𝐷 ∈ [0.31, 0.39], 𝑝 < 0.0001) because this design decision, along with HRT, determines the total interfacial area and the total amount of encapsulant material in a reactor and they should be optimized simultaneously in system design.