Applications of materials as additives in anaerobic digestion technology

Production of renewable energy is one of the prime focuses of modern research and industry. Anaerobic digestion (AD), as a mean for biogas production, is hence the fastest growing segment within the waste management industry. AD is a naturally occurring series of microbial processes, encompassing the breakdown of organic materials, ensuring energy recovery with the reduction of greenhouse emissions and facilitating a sustainable development of energy supply from waste. Nevertheless, the efficacy of AD may drastically reduce due to problems such as substrate diversity, ammonia inhibition, microbial flora washout, low methane yield, feedstock purity, etc. In this review, we cater to these problems that lead towards process instability and inefficiency through the applications of various synthetic, biological and nanomaterials. Different support materials tend to enhance biogas production by facilitating the microbial growth, via electron transfer, avoiding toxic concentrations of ammonia, biofilm/anaerobic granular sludge formation, nutrient supplements, H2S removal, CO2 sequestration and bio-augmentation. This review focuses on the unique features of support materials and their role in microbial and substrate dynamics as the reinforcement strategies in AD biogas production.