Metabolic effects of Fe0 on simultaneously eliminating excessive acidification and upgrading biogas in mesophilic or thermophilic anaerobic reactor

Excessive acidification and low methane (CH4) percentage are technical challenges restricting anaerobic digestion (AD) of kitchen waste, especially under high organic loading rate (OLR) conditions. Although the contribution Fe0 powder to excessive elimination CH4 yield improvement in mesophilic AD (MAD) has been extensively reported, its impact on thermophilic (TAD) process with more frequent problem is rarely studied. Moreover, difference microbial interactions metabolic pathways between MAD TAD reactors regulation was still unclear. In this study, we compared performance dosing biogas upgrading quality both at different OLRs. The results showed that or (less than 70%) control without addition, addition OLR 35 gVS/L were 470.88 mLCH4/gVS 270.40 mLCH4/gVS, higher composition 81.32%–82.23% 83.68%–88.48% respectively. Microbial diversity analysis a sharp distinction Fe0. Analyses co-occurrence networks pathway presented hydrogenotrophic methanogenic pathway, acetoclastic methanogenesis, dominant as enhanced interspecies hydrogen transfer Methanoculleus some producers, condition. contrast, syntrophilic acetate oxidization - which dominated by Methanothermobacter Alkaliphilus Pelotomaculum, sole reactors. will shed lights mechanisms waste conditions, offering new insight into development efficient energy conversion technologies.