A study on biogas production from cassava peel and stem in anaerobic digestion reactor

Abstract

Many countries are suffering from the limitation of clean energy sources. Global management nowadays is facing severe problems and challenges in supply energy without destroying the environment. Anaerobic digestion (AD) is a solution, that makes the best use of organic matter by changing it to biogas to generate of renewable heat, electricity, and fuel. Here, we demonstrate the potential of the feedstock—cassava peel (CP) and cassava stem (CS)—to produce biogas, using a continuous laboratory-scale AD reactor (2L working volumes) operated at mesophilic conditions (T = 35 °C), an organic loading rate of 0.0756 gCOD/L.day, for 25 days. Cassava peel depicted high total suspended solids (TSS = 404 mg/g), biochemical oxygen demand (BOD5 = 0.28 mg/L), and chemical oxygen demand (COD = 378 mg/L) as compared to cassava stem. Moreover, the hemicellulose and cellulose in the peel are higher than the stem. A compost tea from the vermicomposting process is using as an inoculum for the AD reactor. The highest biogas yield (~ 1000 ml) obtained from cassava peel with seeding. Polynomial trends with acceptable regression obtained for biogas generation and operating pH. The results also indicate that in the selected experimental range (25 days), the highest yield of biogas generation can be observed in the range of day 13 to day 20 to be around 56.1–54.5% (CP + S) and 54.5–50.0% (CS + S), respectively. Finally, the overall trends of cumulative biogas and cumulative methane yields in both CP + S and CS + S show linearity with almost positive slops.