Enhancing biogas production in anaerobic digestion by the addition of oxidized and non-oxidized biochars

Abstract Anaerobic digestion (AD) is a well-known biological conversion process to obtain gaseous biofuel from organic matter: in fact, upgrading biogas biomethane mean substitute conventional natural gas. It also known that biochar can improve the production AD processes. In this work, different biochars have been produced various feedstocks at conditions. Biochars obtained carbonization of wheat straw (WS) and poplar (P) were Thermo Gravimetric Analyser lab scale, temperature 400 °C 2 h retention time maximum temperature, with heating rate 20 min −1 . Another (Pc) was pilot plant (CarbOn, RE-CORD) working oxidative pyrolysis conditions, range between 500 600 °C. oxidized Oxone® using two methods (ball-milling simple aqueous solution mixing) increase amount functional groups on their surface. Oxidized (Ws_Ox P_Ox) characterized by FTIR, BET, CEC, impact investigated through scale biochemical methane potential (BMP) test maize silage as substrate. 0.33 g used for each treatment. BMP shows all batches containing additive more than control (C). WS_Ox P_Ox respectively + 7.7% 11.3% C, obtaining higher productivities respect not biochars. The addition P Pc similar performances AD, thus highlighting no significant differences are due scales parameters same feedstock. This study highlights how examined (nature feedstock, parameters, size its concentration AD), presence specific surface influences performance.