The study on granular activated carbon to promote thermophilic anaerobic digestion
PAN Yi-ran1, CUI Kang-ping1, ZHANG Shuo2, CHANG Jia-li2, HUANG Xia2
1. School of Resources and Environment, Hefei University of Technology, Hefei 230009, China;
2. State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
Recent studies have suggested that granular activated carbon (GAC) could improve the methane production from mesophilic anaerobic digestion (MAD) by facilitating direct interspecies electron transfer (DIET). However, it is unclear whether the involvement of GAC could enhance methane production from thermophilic anaerobic digestion (TAD) and its roles in stimulating methane production have not been clarified. Here, the effect of GAC addition on methane production from TAD was studied through batch experiments with sodium acetate as substrate. The results indicated that the utilization of GAC significantly promoted the TAD process. But, through estimating the microbial biomass with quantitative PCR, it was revealed that the contribution of GAC to the microbial biomass is tiny. This may imply that the enhancing methane production by GAC is not achieved by increasing the amount of biomass. Moreover, significant alterations in microbial community structure were detected between reactors with and without GAC through high-throughput sequencing. In presence of GAC, Thermodesulfolbiaceae, Anaerobaculaceae and Methanosacinacea were enriched/dominant. Thus, it is proposed that, in the TAD process, GAC may play a role in the enrichment of specific species and accelerate the newly formed DIET pathway mediated by thermophilic microbiota.
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