Bioconversion of fruit wastes and effects of thermophilic hydrolysis for banana peel digestion

Abstract

Methane production potential of tropical fruit wastes were compared by anaerobic digestion assay and stoichiometric Buswell's equation. Methane yields were in the order of banana peel, longan waste, and rambutan waste (330.6, 268.3, 234.6 and 193.2 mLCH 4 /gVS). Their calculated biodegradability related well with structural composition and properties. In continuous system operations on banana peel at feed concentrations 1%TS and 2%TS, mesophilic single stage digester (20-day HRT) failed at 2%TS. Prehydrolysis thermophilic reactor (4-d HRT) was placed as pre-treatment to mesophilic reactor (20-d HRT). Higher biogas and energy yields were obtained and greater system stability was achieved over the single stage digestion. The energy yield of 2510.9 kJ/kgVS was achieved at a feed concentration of 2%TS with thermophilic prehydrolysis.