Relationship between volatile fatty acids and alkalinity in anaerobic digestion of food waste

In this study, the content of volatile fatty acid such as the presence of acetic acid, propionic acid and butyric acid and its relationship with total alkalinity in the anaerobic digestion system was examined. The material used in this system is the combination of food waste and sludge from anaerobic pond. Each sample takes about 45 days for the whole anaerobic process to complete in a batch reactor. Anaerobic system is very sensitive to pH changes and it is very important to maintain pH of 6.5 to 8 for a healthy system. This is because the main groups of bacteria living
in this system are either acetanogenic or methanogenic bacteria. The latter need the alkali condition but the acetogenics need acid conditions. Thus the needs for pH balance in the system.