Biogas Potentials of Maize Cob Co-Digested with Animal and Plant Waste under the Effect of Bentonite Catalyst

Abstract

This paper evaluates the effect of various contents of bentonite catalyst (B-cat) on biogas production from lignocellulosic biomass (maize cob), cow dung and food waste. It was hypothesised that the pore and the negatively charged B-cat may likely have a reducing effect on the production of inhibition in the digester. The experiment involved milling of the maize cob and determining some of its chemical composition prior and after the pretreatment. The milled maize cob was co-digested with cow dung and food waste in an airtight digester. The results indicated that highest cumulative biogas production of 561 ml was documented with digester where 2.5 g B-cat was applied one week after the commencement of the experiment. However, when the catalyst was applied at the onset of the experiment, application of 3.5 g B-cat became the most appropriate content with highest cumulative biogas production of 452 ml throughout the entire experiment in that category. ANOVA analysis revealed that the effects of the application doses is statistically significant (P<0.05) at 95% level of confidence irrespective of the time of application. Moreover, when application time of B-cat was delayed by a week, higher biogas out was obtained with lower dose (2.5 g) of B-cat. It is concluded that the introduction of B-cat in the digester one week after the commencement of digestion involving maize cob, cow dung and food waste is appropriate.