Biogas Production from Co-digestion of Cattle Manure, Oryza sativa and Phaseolus vulgaris in Plug Flow Digester

Abstract

The possibility for producing biogas from the simultaneous co-digestion of phaseolus vulgaris, oryza sativa, and cattle dung in a plug flow digester was examined. Oryza sativa and phaseolus vulgaris are very common food waste found in Nigeria. The market-purchased food waste was ground in a kitchen processor to a thickness of less than 2 mm. Three digesters with effective capacities of 0.0083 m3 were created. The digesters were fed with food waste and cattle dung which served as the inoculum at different feeding rates of 0.05 kg every three days, 0.1 kg every three days, and 0.3 kg every three days. During the trial period, chemical oxygen demand (COD), total solids (TS), and volatile solids (VS) were measured to ascertain the system's effectiveness. The parameter utilized to gauge the process stability was pH. When feeding at a rate of 0.1 kg every three days, digester 2 produced the most gas. The least amount of biogas was generated by digester 3 at a feed rate of 0.3 kg every three days. After 19 days, the effluent for digesters 1, 2, and 3 had COD values of 810.49 mg/l, 940.17 mg/l, and 987.68 mg/l, respectively. After 20 days, the effluent from digesters 1, 2, and 3 had amounts of TS and VS that were, respectively, 1.82%, 6.24%, 10.76%, and 10.70%, 6.24%, 42.81%. The measured pH range was 7.98 to 8.86, and there was no discernible difference across the three digesters (p>0.05). The ideal feed rate for the digestion of waste and biogas production was determined to be 0.1 kg every three days.