ANAEROBIC DIGESTION OF FOOD SUBSTRATES FOR BIOGAS PRODUCTION

Authors: Ebunilo P.O, Okovido J, *Ikpe A.E

DOI Info: N/A

ABSTRACT

This study focused on the evaluation of biogas production from digestion of food substrates. Three materials (steel, brick and plastic) were considered for the bio-digester Plastic was selected based on cost, weight, availability and assembly. Incorporated within the setup was a biogas scrubbing unit consisting of steel wool for (H2S) removal, distilled water for (CO2) absorption and Type B silica gel for water absorption/drying of purified biogas (CH4) before storage. The digestion process was carried out using multiple food waste and water at different masses of 10 kg, 15 kg, 20 kg and 25kg in a mix ratio of 1:1. The mixture of 10 kg of multiple food waste and water in the same ratio produced raw biogas of 151 g and purified biogas (CH4) of 115 g while 15 kg of the same feedstock combination produced raw biogas of 255 g and purified biogas of 204 g. Furthermore, 20 kg of the same feedstock combination produced raw biogas of 354 g and purified biogas of 303 g, whereas, 25 kg of the same feedstock combination produced raw biogas of 425 g and purified biogas of 383 g. A trend was established where the biogas productivity curve started from a minimum point but later rose to a constant peak point where substrates was observed to have stabilized, followed by gradual decline until a minimum point was attained when the food substrate was no longer active in terms of biogas production.

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