The role of biochar to enhance anaerobic digestion: A review

Biochar, one of the products of thermochemical conversion of biomass, possesses specific physiochemical properties such as conductivity, pore adsorption, surface functional groups, and cation exchange capacity. Anaerobic digestion (AD) as a classical bio-wastes conversion technology, suffers from inhibitions, process instability, and methanogenic inefficiency which limit its efficiency. With the advantages of pH buffering, functional microbes enrichment, inhibitors alleviating, and direct interspecies electron transfer (DIET) accelerating, biochar suggests a promising application as additives for AD. Herein, this paper reviewed the noting physicochemical properties of biochar, and discussed its roles and related mechanisms in AD. Further, this paper highlighted the advantages and drawbacks, and pointed out the corresponding challenges and prospects for future research and application of biochar amending AD.