Sudarman, Roro Heni Hendaryati, Achmad Fauzan Hery Soegiharto, Dyanu Moulana Ismail, Rizki Raihan Ramadhan, Willy Satrio Nugroho, Yepy Komaril Sofi’i
The global energy crisis caused by fossil fuel depletion has prompted a shift toward renewable energy sources. This study investigates the effect of rice water as a co-substrate on methane production via anaerobic digestion of fruit (Artocarpus heterophyllus), vegetable (Lactuca sativa), and grass (Cenchrus purpureus) waste. To understand their chemical and structural properties, organic substrates were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX). Experiments were conducted using a 10 L custom reactor over 15 days. The combination of jackfruit and lettuce produced the highest methane concentration (637.75 ppm), followed by jackfruit alone (479.53 ppm), representing a 32.96% increase due to co-substrate addition. In contrast, grass and lettuce yielded lower concentrations (430.68 and 540.59 ppm, respectively). The high carbohydrate and microbial content in rice water enhanced hydrolysis and acidogenesis, accelerating methane formation. Statistical analysis confirmed that substrate type significantly influenced methane output (p < 0.05), while fermentation duration showed no significant effect (p > 0.05). This study concludes that rice water substantially boosts methane yield in mixed organic waste digestion, particularly with jackfruit and lettuce, offering a simple, low-cost enhancement for small-scale biogas systems. This is an open access article under the CC BY-NC-SA 4.0 license. CC BY NC SA
Department of Mechanical Engineering, Faculty of Engineering, University of Muhammadiyah Malang, Raya Tlogomas Street No. 246, Malang, 65144, Indonesia; Department of Mechanical Engineering, Faculty of Engineering, University of Brawijaya, Mayjend Haryono Street No. 167, Malang, 65145, Indonesia
