Simulation and Control of an Upflow Anaerobic Sludge Blanket (UASB) Reactor Using an ADM1-Based Distributed Parameter Model

In this study, an ADM1-based distributed parameter model was used to evaluate the influence of organic loading and external recirculation on upflow anaerobic sludge blanket (UASB) reactor performance. A process control strategy based on the manipulation of the external recirculation-to-influent ratio was proposed. This strategy was compared with the traditional dilution rate-based method to control the effluent chemical oxygen demand (COD) concentration and methane gas flow rate. Furthermore, a simple rule, which suggested when and how to use the dilution rate and the recirculation-to-influent ratio in a multivariable control system, was proposed. The simulations showed that the use of a multivariable control system improved reactor performance and stability, in comparison to a traditional dilution rate-based control method.