Mathematical modeling of methane production and sulfate reduction in upflow anaerobic sludge blanket reactors: Calibration, validation and prediction of reciprocal effects

Mathematical models are important tools for understanding and optimizing the performance of biotechnological processes. A user-friendly mathematical model is developed to simulate the sulfate reduction and methanogenesis of upflow anaerobic sludge blanket reactors. The good fit between the simulated and experimental concentrations reflects the model's capability in simulating reactor performance when there are variations in operational conditions. The model with optimized parameters is used to quantitatively and systematically account for the interaction of influent organic loading rate and the ratio of organic to sulfate, influent chemical oxygen demand and sulfate concentrations, and influent organic composition and chemical oxygen demand concentration. The interaction between the OLR (3∼72 g-COD/L/d) and C/S ratio (0.5∼20) greatly influenced the ethanol concentration, yield ratio of methane and sulfate concentration. The removal of sulfate in the reactor was more influenced by the C/S ratio than the OLR. It provides a theoretical basis for reactor process optimization and control and greatly saves time required for experimental investigations.