Analysis of vegetable waste degradation effectiveness for biogas feed in single batch reactor

Abstract

An anaerobic ecosystem requires organic compounds and nutrients, such as nitrogen and phosphorus to produce biogas. The biogas production, in general, needs the C/N ratio of 25–30 for the proper development of a biological process. To reach the optimal C/N ratio, the importance of the balance between the nutrients in the anaerobic digestion process was assessed at laboratory scale. The first method stage used in this study is the utilization of EM-4 microbial starter and 3% of NaOH in the pretreatment process of vegetable waste feed which aim to increase the C/N ratio meanwhile maintain the protein content itself. The second stage is the addition of GP-7 microbial starter and cow dung waste mixture during the methanogens process which shows satisfying results. Regardless the retention time which takes less than two times longer than the process without vegetables waste, the methane gas amount produced in this study (47%) is comparable to the one produced from cow dung waste only (50%). In spite of that methane production still tends to increase after 45 days of processing time.