Effects of biochars derived from different feedstocks and pyrolysis temperatures on the anaerobic digestion of kitchen waste

Abstract

The aim of this work was to investigate the effects of biochars derived from different feedstocks and pyrolysis temperatures on the anaerobic digestion (AD) of kitchen waste (KW). Nine biomass feedstocks (corn straw (CS), Dicranopteris dichotoma (DD), bamboo (B), KW, tea residues (TR), mushroom cultivation waste (MW), cassava lees (CL), Chlorella (C), and sargassum (S)) were pyrolyzed at different temperatures (300 °C, 500 °C, and 800 °C). Biochar varied in physicochemical properties (e.g., specific surface area, total pore volume, and organic functional group) depending on both feedstock type and pyrolysis temperature. This further impacted the enrichment of functional microbial consortia and development of methanogenic pathways, resulting in a varied AD performance. The addition of biochars generated respectively from CS, MW, and S at 800 °C, 300 °C, and 500 °C significantly improved the maximum methane production rate (Rm) and methane yield, while other biochars enhanced either Rm or methane yield. Therefore, the efficacy of biochar on methanogenesis associated with both the feedstock type and pyrolysis temperature. The findings offer a beneficial reference for the selection and application of biochar to improve the AD performance.