Optimization of biogas production through selection of appropriate Inoculum-to-Substrate ((I/S) ratio

Abstract

The impact of Inoculum-to-Substrate (I/S) ratio on the optimization of biogas yield from the co-digestion of FW and MH was investigated in five anaerobic reactors B-1 to B-5 at 37±1 o C. Cumulative biogas yield of digester B-3(28.92 L/gVS) with the I/S ratio 1 was higher than that of the other digesters. Simulation study through adoption of Gompertz model (modified) showed a large reduction in latency (λ) by 59.7% with increase in I/S ratio from 0.25 to 1, which indicates that the time taken for methanogenesis to begin was reduced by over 59%. Increase in I/S ratio had positive effects on maximum specific biogas production (Rm) and maximum biogas production potential (A) with reactor B-3 having the largest (Rm) and (A) values of 1.26 L/gVS/day and 29.58 L/gVS respectively. Lower I/S ratios of 0.25 and 0.5 were found to rather decrease biogas production. Biogas yield at I/S ratios 2 and 4 was lower than the yield at ratio 1.

Optimization of Biogas Production from Anaerobic Co-Digestion of Fish Waste and Water Hyacinth

“…This inhibition was due to the formation of intermediate products which are inappropriate for conversion by methanogenic bacteria to biogas. When there is overloading, the production of organic acids increases quickly, then inhibition of methanogens activity [11]. Similar ndings were reported by Gooch, Jnr, Rabii et al,and Shen [26,34,35,36], overloading caused the microbial activity to be inhibited, which decreased the rate of biogas generation.…”

“…Before being sold, over 70% of sh is processed. Waste from sh makes up between 20-80% of this total [7,10,11,12]. Large amounts of waste including heads, intestines, bones, viscera, and scales are created during the processing of sh, and the majority of this waste is made up of lipids and proteins which are underutilized and ignored [7,9,10,12,13].…”

“…It has been discovered that using the codigestion principle to produce biogas from a variety of wastes is an e cient way to maximize the amount of biogas produced [2,11]. The co-digestion of different organic materials has been used to increase the C/N ratio, improve gas and methane generation, and enhance good synergy for encouraging bacteria activity [11]. However, to ensure the longevity and sustainability of industrial anaerobic digestion facilities, the best possible mix of process variables and substrates must be used most economically [11].…”

Optimization of biogas production from anaerobic co-digestion of fish waste and water hyacinth

“…This might be explained by the presence of an insufficient amount of methanogens. This inhibition was due to the formation of intermediate products which are inappropriate for conversion by methanogenic bacteria to biogas and when there is overloading, the production of organic acids increases quickly, then inhibition of methanogens activity [ 11 ]. Similar findings were reported by Shen et al, Jnr et al, Labatut et al, Rabii et al, [ 25 – 28 ], overloading caused the microbial activity to be inhibited, which decreased the rate of biogas generation.…”

“…The application of co-digestion to balance the C/N ratio, improve gas and methane generation has been reported by previous studies [ 7 ]. The process enhances good synergy which encourages bacteria activity [ 11 ]. In addition to promoting co-digestion, the biogas yield can be improved by optimizing the process variables such as organic loading rate (OLR), inoculum concentration (IC), pH, dilution, carbon to nitrogen (C/N) ratio, substrate ratio, retention time, dilution, and temperature [ 6 ].…”