Biogas Production from Sugar Beet Wastes in an Overload Bioreactor with pH Adjustment

Subject Areas : Renewable Energy

Misagh Keramati ¹ , Hossein Beiki ²

1 - M.Sc., Student, Chemical Engineering, Quchan University of Technology, Quchan, Iran
2 - Assistant Prof., Department of Chemical Engineering, Quchan University of Technology, Quchan, Iran. *(Corresponding Auther)

Received: 2017-04-01 Accepted : 2017-10-25 Published : 2020-09-22

Keywords: pH Adjustment, Anaerobic digestion, Sugar Beet Wastes, Biogas,

Abstract :

Background and Objective: Considering the importance of environmental protection and necessity of using new energy sources and innovative fuels, in this study, biogas production from sugar beet wastes using a batch lab-scale bioreactor was investigated experimentally. Method: All experiments were done at constant temperature of 37±1 oC with using water bath. Four reactors with the same feed concentration and condition put in a circulated water bath. pH was adjusted in the reactors for the first 4 days on 7, 8 and 9. Substrate to inoculum (S/I) ratio in the reactors was constant and equal to 6:1. Finding: In the over load mono-digester system with high S/I ratio, due to the sharp drop in pH, biogas couldn’t be produced. By adjusting the pH, even for such a system, biogas production can be achieved, although the efficiency of the process is low.  Discussion and Conclusion: The results revealed that, whilst biogas was not produced in the reactor with high S/I ratio, pH adjustment made it possible to generate biogas. Mole fraction of methane in biogas produced in the reactors with pH adjustment were 35-50%. Biogas production occurred with long time delay, so that after 14 days, very little or no biogas was produced. Maximum volume of biogas was produced in reactor with pH=8. Whilst in the reactor with pH=9, biogas produced with high methane purity.  

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