Advances, trends and challenges in the use of biochar as an improvement strategy in the anaerobic digestion of organic waste: a systematic analysis

Abstract

A recently strategy applied to anaerobic digestion (AD) is the use of biochar (BC) obtained from the pyrolysis of different organic waste. The PRISMA protocol-based review of the most recent literature data from 2011–2022 was used in this study. The review focuses on research papers from Scopus® and Web of Knowledge®. The review protocol used permits to identify 169 articles. The review indicated a need for further research in the following challenges on the application of BC in AD: i) to increase the use of BC in developing countries, which produce large and diverse amounts of waste that are the source of production of this additive; ii) to determine the effect of BC on the AD of organic waste under psychrophilic conditions; iii) to apply tools of machine learning or robust models that allow the process optimization; iv) to perform studies that include life cycle and technical-economic analysis that allow identifying the potential of applying BC in AD in large-scale systems; v) to study the effects of BC on the agronomic characteristics of the digestate once it is applied to the soil and vi) finally, it is necessary to deepen in the effect of BC on the dynamics of nitrogen and microbial consortia that affect AD, considering the type of BC used. In the future, it is necessary to search for new solutions in terms of the transport phenomena that occurs in AD with the use of BC using robust and precise mathematical models at full-scale conditions.

A Perspective of Solid-State Fermentation As Emergent Technology for Organic Waste Management in the Framework of Circular Bioeconomy

“…In recent years, anaerobic digestion has undergone an unprecedented boost due to the search of renewable and locally-available sources of energy. , This increase has derived in the implementation of new anaerobic digesters, the search for additives to improve methane yield, such as biochar or nanomaterials, and a considerable number of recent publications on biogas upgrading research . Unfortunately, this boost has not been accompanied by a similar increment either in implementation or in research to find alternative ways to valorize the other product of anaerobic digestion: digestate.…”

Characterization of biochars of different origin and application to the anaerobic digestion of source-selected organic fraction of municipal solid waste under batch conditions and at different dosages

“…However, it faces several challenges, including low methane productivity, long retention time, low organic loading rate (OLR), instability related to ammonia and acid inhibition, and metal accumulation (Pramanik et al, 2019;Kumar et al, 2021;Zhao et al, 2021). One of the strategies used to improve AD is the incorporation of additives such as microbial inoculant, enzymes, biological metabolites, carbon-based additives, chelating agents, and nanoparticles (Parra-Orobio et al, 2023).…”