Production of Biogas by Anaerobic Digestion of Food Waste and Process Simulation

Anaerobic Digestion is a biological process that takes place naturally when microorganisms break down organic matter in the absence of oxygen. In an enclosed chamber, controlled anaerobic digestion of organic matter produces biogas which is predominantly methane. The produced methane then can be directly used for rural cooking; or after certain conditioning, can be used in onsite power generation, heating homes or as vehicular fuel. Besides, food waste is increasingly becoming a major problem in every society imposing serious economic and environmental concerns. For this reason, many contemporary researches are emphasizing in finding sustainable solutions to recycle and produce energy from such waste. In this context, this paper aims to study and optimize the production of biogas from food waste (rice). For the experiment, an existing wet digestion biogas plant installed in Islamic University of Technology was used. The food waste (rice) for the research was collected from the cafeteria of Islamic University of Technology. Furthermore, a process simulation was performed by PROII software to estimate the methane production rate. Eventually, the simulated and experimental results were compared. The duration of the study period was 120 days. The experimental results showed that an average specific gas production of 14.4 kg-mol/hr can be obtained for 0.05 kg-mol/hr of starch loading rate. In case of the simulated results, the gas production was found to be 19.82 kg-mol/hr for the same loading rate of starch. The percentage of methane and CO₂ obtained in the biogas plant was 69% and 29% respectively.