A study on Anaerobic co-digestion of food waste and POME

Abstract

Anaerobic digestion is a process where microorganisms break down biodegradable material in the absence of oxygen. It will produce mainly CH4 and CO2. Meanwhile, co-digestion is the simultaneous digestion of a homogenous mixture of two or more substrates. The first objective of this study was to analyze the characteristics of the digestate through anaerobic co-digestion of food waste and POME with different ratio. Secondly was to determine optimum biogas production during anaerobic codigestion of food waste and POME. Anaerobic co-digestion showed a significantly improvement of biogas productivity. In this study, it was used different ratio of food waste and POME to see the different effect of characteristics to the biogas production. From the experiment, the result shows the anaerobic co-digestion with high ratio of food waste and POME produced higher methane in percentage rather than the low ratio of food waste and POME but it needs longer retention time than others. Temperature controlled for this experiment is under mesophilic which is 35°C. Several parameters are conducted in this experiment such as pH, total alkalinity, C/N ratio, and biogas production. The pH value of reactor 1 is range between 5-5.8, while reactor 2 is between 6-6.9 and last reactor is between 4 – 6. The C/N ratio of three reactors mostly range 25-30 and the production of biogas shows the reactor 2 has highest value which is 28.6%, reactor 3 obtained 6.3% and reactor 1 is 4.5%. Therefore, from the result we can conclude that the pH which is more to neutral will produce more methane gas and the increase of ratio will increase the yield of biogas production due to the microbe keep growing and transform organic matter to biogas production. In addition, the suitable C/N ratio is range 25-30 shows the good process of anaerobic co-digestion because if it is too low it produces ammonia inhibition whereas a high ratio will lead deficiency.