Biogasification of Cassava Residue for On-Site Biofuel Generation for Food Production with Potential Cost Minimization, Health and Environmental Safety Dividends

Convenient energy sources like biomethane and electricity are scarce commodities in cassava producing countries that depend on wood and charcoal for energy supply. Combustion of wood and charcoal releases substances that impair human health. In 2016, about 30 million metric tons of cassava peeling residues (CPR) were generated worldwide and discharged into the environment. Apart from deforestation, loss of biodiversity and soil erosion caused by felling vegetation for wood and charcoal recovery, discharge of CPR into the environment exacerbates environmental pollution and health hazards. This study presented biogasification experiments with CPR in a simple, batch, leach-bed, unmixed fermentor. Biofuel yield ranged from 180 to 310 (mean of 252) L CH4 kg(-1) VS-1 while fermentation time ranged from 19 to 33 (mean of 27) days. The substrate contained on average 33% dry matter of which 96% was volatile, and 71% volatile solids reduction was achieved. Furthermore, all electrical and thermal energy required for producing three cassava root food products (flour, gari, and starch) could be generated on-site using CPR as substrate for anaerobic digestion. Consequently, energy paucity, environmental contamination, health hazards associated with cassava processing effluent, and combustion of wood and charcoal, could be mitigated by biogasification of CPR. (c) 2019 American Institute of Chemical Engineers Environ Prog, 38:e13138, 2019