Chapter 10 - Biogas upgradation using integrated anaerobic digestion and microbial electrochemical technologies

Abstract

Anaerobic digestion (AD) is a conventional technology for anaerobically digesting organic waste for the production of biogas. The major component of biogas is methane (CH4) and carbon dioxide (CO2). In addition, other anaerobically reduced byproducts such as hydrogen sulfide (H2S), ammonia (NH3), and hydrogen are also produced till a certain quantity. Biogas enriched with methane (CH4) or hydrogen (H2) is useful and has considerable applications related to energy recovery. Therefore upgraded biogas production by means of abiotic and biotic approaches is important to explore. Abiotic approaches include pressure swing adsorption, water scrubbing, chemical absorption, membrane separation, and cryogenic separation; however, these technologies are either costly and high energy–intensive or less efficient. In the biotic production of methane-enriched biogas, the hybridization of AD with microbial electrolysis cells or microbial electrosynthesis is gaining popularity. Microbe usage and characteristics, electron-transfer mechanism, reactor architectures, and membrane usage play important roles in enhanced and purified biogas recovery. The operating conditions such as temperature and pH also have a significant impact on the performance of the reactors.