Biogas production from chicken food waste and cow manure via multi-stages anaerobic digestion

Biogas is a clean and renewable form of energy that can be produced from organic waste via anaerobic digestion using a bio-digester. Fixed dome, floating drum and plug flow digester is few of typical digester design that has been used around the world. The sizes of these reactors varies depending on the organic loading rate of the available organic waste as well as the retention time of the substrate inside the reactor. In most cases, bio-digester requires large area, constant agitation and very stable environment. Despite its numerous advantages, the potential of biogas technology depends on many factors including feedstock type, reactor design and operation parameters. Even though many studies have been done to understand the effect of these factors, there are not many study that focus on the design of the reactor to optimize the potential of biogas production from food waste. In this study, the use of multi stage reactor that requires smaller footprint will be tested to enhance the gas production rate from solid substrates (food waste and other organic materials). The study includes experiment to study the effect of stages inside the reactor, composition of substrate and size of food waste on the biogas production. The results show that the stages do have effect on the gas production. With the present of stages inside the reactor, the gas production can be increased up to 30 %. In addition, the amount of protein increases gas production. However, if the protein hydrolysis rate is high, it can disturb the process since the methanogenesis favour neutral pH.