Comparative analysis of microwave wet torrefaction and anaerobic digestion for energy recovery from antibiotic mycelial residue

Microwave wet torrefaction (MWT) and anaerobic digestion (AD) are two potential approaches to produce hydrochar fuel or methane energy from biomass. This study comparative analysed the preparation of hydrochar with MWT and biogas production with AD to recover energy and remove antibiotics from antibiotic mycelial residue (AMR). Moreover, MWT was also used as a pretreatment in AD to improve methanogenic performance. The results showed that abamectin was significantly removed by MWT and the highest degradation rate reached 95.0%. The volatiles of AMR, especially hemicellulose, were significantly degraded, and the structure of AMR became incompact and amorphous after MWT. For the preparation of hydrochar, higher temperature (200degree celsius) with long residence time (30 min) was recommended to obtain higher energy yield (>97.2%). Considering the abamectin removal, MWT at 160degree celsius is more suitable for pretreatment of AD, which obtained a higher methane production (327.9 mL/g VS) than the AD of raw AMR (234.0 mL/g VS). This work lays a foundation for energy recovery of high-moisture and toxic biomass.