Hydrothermal pretreatment of sugarcane bagasse pith for biogas production and digestate valorization to biochar

Abstract

Sugarcane bagasse pith is generated as waste from bagasse-based paper industries which is still underutilized and mostly burnt as fuel in boilers. Therefore, an integrated pathway for the value-addition of the pith is explored. In the present study, hydrothermal pre-treatment of pith through response surface methodology and C/N was optimized for enhanced biogas production. At optimized conditions, a maximum biogas yield of 474.3 mL/gVS with ∼55% methane was attained with cellulose and reducing sugar of 59.2% and 3.68 g/L respectively. A severity factor of 3.8–4 was found suitable for cellulose enrichment, reducing sugar and biogas production, and at higher severity, a reduction in the above parameters was observed. Moreover, the digestate-based biochar delivered the highest biochar yield and surface area of 75.8 wt% and 254.47 m2/g respectively. This study is the first of its kind where the bagasse pith has been explored in a biorefinery approach to achieve circularity.