Anaerobic digestion can help mitigate tobacco waste (TW) pollution. Both the mono-digestion of sludge and the co-digestion of TW and sludge were considered in this study. Additionally, the effects of nano-Al2O3 and multi-walled carbon nanotubes (MWCNTs) on these two digestion systems were investigated through a 35 day digestion experiment. The microbial communities in the control reactors and the nano-Al2O3 reactors were also examined. Kinetic analysis revealed that the Rm values for the mono- and co-digestion nano-Al2O3 reactors increased by 8.88% and 13.5% compared with that of the MWCNTs reactor, respectively. Furthermore, the co-digestion system exhibited a 34.8% higher Rm than the mono-digestion system when nano-Al2O3 was added to both systems. Nano-Al2O3 was found to shorten the lag phase, while MWCNTs prolonged the lag phase time. Furthermore, 16S RNA amplicon sequencing results indicated that microbial species such as Methanobacterium sp., Hydrogenispora sp., Lutispora sp., and Ruminiclostridium sp. were more abundant in the nano-Al2O3 reactor. These results demonstrated that biogas production in co-digestion systems was improved. Moreover, nano-Al2O3 addition enhanced biogas production.
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