Biogas production from waste pulps of cassava (Manihot esculenta Crantz) via anaerobic digestion

The huge volume of wastes generated from industries kindles immediate attention, especially those wastes that bring adverse effects to humans and the environment. For one, cassava waste pulps (CWPs) from starch-producing industries are needing attention for its alternate disposal by making value-adding products out of it. In this work, the CWP with pig manure as inoculum was anaerobically digested for the possible production of biogas. The effect of the concentration of pig manure (CPM) and biomass to water ratio (BMR) was scientifically analyzed in relation to biogas yield. The central composite design of the response surface methodology was used as the design of the experiment. Biogas yield was modeled and characterized according to essential properties. The result of the batch experiment obtained a biogas yield of 4.9–7.3 L per kg of CWP. At optimized conditions of 250 gVS of CPM and 1:1.22 BWR (kg/L), the optimum biogas volume was 7.43 ± 0.58 L per kg of CWP. Analysis of the produced biogas via gas chromatography showed a significant concentration of biohydrogen (18.69 ± 1.71%), a highly desirable upshot considering that this gas is highly flammable with less emissions when combusted. Other percent components of the produced biogas include carbon dioxide (38.02 ± 0.71), nitrogen (20.77 ± 1.59), and a trace of methane (0.73 ± 0.28). This work, therefore, proved that CWP can be used for the production of biogas and would eventually provide practical solutions to starch processing industries as it gives promising lucrative routes of CWP with added commercial worth in the production of high-value energy resources like the desirable H2 gas. It poises high potentials with less socio-economic apprehensions while offers numerous environmental advantages.