Optimization of Wastewater Anaerobic Digestion Using Mechanistic and Meta-heuristic Methods: Current Limitations and Future Opportunities

Abstract

Anaerobic digestion is widely used to treat high-strength wastewater and produces methane as a by-product for power generation. Treatment and reuse of industrial effluent also contribute to water conservation efforts. Nevertheless, the sensitivity of anaerobic digestion system proves to be a challenge in ensuring consistent quality of treated wastewater and biogas production. Hence, it is essential to devise an effective model and control system that accurately represent the dynamics of anaerobic digestion and can respond to changes in process parameters with proper fault detection and output prediction. This article provides a comprehensive review on (1) the anaerobic digester technology and parameters governing its efficiency, (2) mechanistic and meta-heuristic models used to describe this process, and (3) the process control strategies. In this study, adaptive controller was found to be able to provide wider options in terms of controlled and manipulated variables. Nevertheless, an in-depth study is essential to determine the best controller to be applied for a particular system where further optimization can be done to achieve the best performance.