Comparing activated carbon of different particle sizes on enhancing methane generation in upflow anaerobic digester. (November 2015) - Xu, Suyun
Highlights: Both PAC and GAC could promote the syntrophic metabolism of alcohol and VFAs. PAC is superior to GAC on the enhancement of biomethane generation process. PAC provides more abundant micropore–mesopore structure for bacteria to colonize. Microbial community colonized on PAC and GAC was characterized and compared. Abstract: Two sizes of conductive particles, i.e. 10–20 mesh granulated activated carbon (GAC) and 80–100 mesh powdered activated carbon (PAC) were added into lab-scale upflow anaerobic sludge blanket reactors, respectively, to testify their enhancement on the syntrophic metabolism of alcohols and volatile fatty acids (VFAs) in 95 days operation. When OLR increased to more than 5.8 g COD/L/d, the differences between GAC/PAC supplemented reactors and the control reactor became more significant. The introduction of activated carbon could facilitate the enrichment of methanogens and accelerate the startup of methanogenesis, as indicated by enhanced methane yield and substrate degradation. High-throughput pyrosequencing analysis showed that syntrophic bacteria and Methanosarcina sp. with versatile metabolic capability increased in the tightly absorbed fraction on the PAC surface, leading to the promoted syntrophic associations. Thus PAC prevails over than GAC for methanogenic reactor with heavy load.