Non-conventional Anaerobic Bioreactors for Sustainable Wastewater Treatment

Conventional anaerobic bioreactors have proven to be useful for energy recovery and removing organic pollutants from wastewater. Unfortunately, the application of most conventional anaerobic systems is limited due to their applicability over a narrow range in substrate composition and single type of pollutant removal. The background of the research and development for non-conventional anaerobic bioreactors mainly includes design limitations, technical and economic issues along with environmental impacts from traditional systems. In this connection, the initial approach for developing non-conventional bioreactors included the improvement on existing conventional anaerobic bioreactors with pre- and post-treatment processes. As these improvements only increased the pollutant removal efficiency up to a certain level, research initiatives were carried out to develop non-conventional hybrid systems. These non-conventional bioreactors usually involve a combination of conventional biological system with physical/chemical treatment process to aid the removal of non-biodegradable pollutants. Recently developed non-conventional systems include the modifications in bioreactor designs such as bio-electrochemical systems, multistage bioreactor arrangements and hybrid anaerobic processes. Performance evaluation of these non-conventional anaerobic systems shows improved product yield and efficient pollutant removal compared to the traditional processes. The key findings from this discussion were listed in the conclusion section along with future insights for this technology.