Biogas Production from the Potato Peel Waste: Study of the Effect of C/N Ratio, EM-4 Bacteria Addition and Initial PH

Abstract

Objective: The objective of this study was to examine the effect of the C/N ratio, EM-4 addition and initial pH on the yield of biogas from potato peels.   Theoretical Framework: In this topic, the concept and theory of biogas production from potato peels on a laboratory scale is presented, then the best conditions and kinetic constants are studied using the Gompertz model.   Method: The variables in this study were the C/N ratio of 25 and 30, the EM-4 addition of 10%v/v, and initial pH of 6.8 and 7. This research was conducted on laboratory scale digesters under batch system. This study also discussed the kinetics of biogas production using the modified Gompertz model.   Results and Discussion: The results showed that the C/N ratio of 30 produced a more biogas yield 17.6-26.1% compared to the C/N ratio of 25. The addition of EM-4 bacteria resulted in a more biogas yield 17.8-23.4% compared to the without addition case. The initial pH of 7 resulted in a more biogas yield 26-29% compared to the initial pH of 6.8. In kinetic analysis, the C/N ratio of 30, with EM-4 addition of 10% and initial pH of 7 resulted the greatest values of the maximum biogas production (A) which was 6,570.24 mL/grTS and the biogas production rate (U) which was 168.56 mL/grTS.day and resulted the lowest value of the minimal biogas formation (λ) which was 13.69 days, with R2 = 0.998.   Research Implications: The practical and theoretical implications of this research are discussed, providing insight into how the results can be applied or influence practice in the field of renewable energy in the form of biogas from potato peels.   Originality/Value: This research contributes to the literature by presenting the concept of biogas production using potato peel as raw material. The relevance and value of this research is proven by the C/N ratio, EM-4 bacteria and pH were proven to increase the productivity of biogas from waste potato peel.