Advancing sustainable organic waste management: A comparative analysis of fixed media and conventional anaerobic digestion systems

Organic waste is currently causing a huge challenge for the planet. For many years, managing waste was mostly about dumping it in landfills. On the other hand, anaerobic digestion is now proving to be a good solution for turning waste into usable energy. This study focused on understanding biogas formation from organic substrates of food wastes and cow dung slurry through plastic material in a continuously stirred tank reactor (CSTR). The main purpose of the experiment was to turn waste into biogas through semi-continuous anaerobic digestion in a pilot reactor of 1000 L, all at regular ambient temperature. At 4 points inside the digester, 100 units of plastic media, made for high porosity, were installed. The mixer blade in the tank was designed to ensuring continuous mixing of feedstock and microbial communities. The experiments involved maintaining a retention time of 30 days and an organic loading rate of 1 kg COD/m3⋅ day. It was found that using fixed media helped produce more biogas, giving an average output of 300 liters each day. The system produced a maximum amount of 67.3% methane, demonstrating good conversion of organic waste into energy. The treatment system reached high reduction rates for COD, TS, and VS, which were 63.64%, 66.68%, and 67.76%, respectively. Based on the positive findings, a local prototype biogas system was formed to safely process family organic waste and fuel projects for renewable energy.