The new strategy of using pine-cone biochar to enhance anaerobic digestion of liquor wastewater for methane production

Abstract

This work investigated the effects of pine-cone biochar (PBC) as an additive on anaerobic digestion process of liquor wastewater. Results showed that the best results were achieved at a dose of 2.5 g/L, with a peak cumulative methane production of 71%. PBC facilitated the hydrolysis process and favored the microbial secretion of humic acids, increasing the activity of the electron transport system and the conductivity of the sludge. Microbial analysis demonstrated that PBC enriched the growth of Geobacter, Methanosarcina and Methanosaeta groups participated in direct interspecies electron transfer, and Latescibacteria, chlamydiae and calditrichaeota groups as key microorganisms in the hydrolysis process. Finally, XRD and FT-IR analyses showed that the compositions and functional groups of PBC could accelerate electron transport while acting as a buffer. The techniques and findings showcased here can serve as a helpful benchmark toward enhancing the effectiveness of anaerobic digestion during the processing of liquor wastewater.