Waste analysis is one of the most important steps in the anaerobic digestion process. Knowing the
general composition of the substrate (input material) to the system is essential for calculating the amount
and composition of the biogas produced as well as the amount of energy contained in the biogas. The
focus of this paper is on a general mixed fruits and vegetables waste that is found traditional market in
Pontianak city. A major limitation of anaerobic digestion of vegetable wastes is the rapid acidification due
to the lower pH of wastes and the larger production of volatile fatty acids (VFA), which reduce the
methanogenic activity of the reactor. The characteristics of the waste substrate used as feed were shown in
Table 1. The moisture content of waste was found to be 48%. The high moisture content verified that
the fruit and vegetable waste was not ideal for incineration or landfilling. The relationship between the
amount of carbon and nitrogen in the organic material is presented by the C/N ratio. Bacteria normally use
up carbon 25-35 times faster than they use nitrogen.