Anaerobic fermentation of kitchen waste

Abstract

Global warming is leading to an increase in the production of renewable energy and the prevention of harmful emissions into the atmosphere worldwide. Many countries around the world are developing special programs to get more green energy. There are currently fifty-two biogas plants in Latvia. Forty-eight of them use agricultural waste. The kitchens of households and catering companies also generate a lot of organic waste. If they are not recycled, methane and carbon dioxide are released into the atmosphere during decomposition in landfills during anaerobic fermentation. Organic kitchen waste should be used as a raw material for biogas production. Biogas could be used to generate heat, electricity or as a fuel for vehicles. Energy prices have risen sharply in Latvia and Europe. Therefore, biogas producers are intensively looking for cheaper raw materials. They need to know how much methane can be extracted from each feedstock. In this study, we found out how much methane can be obtained from four food waste that is often thrown away in food waste bins. We fermented banana peel, orange mandarin peel, onion residues and peel, as well as kiwi peel in fourteen bioreactors at 38 oC. In order to find out how much gas could still be obtained from the inoculum, it was fermented in two bioreactors. The process took 30 days. Most methane was obtained from onion residues and peel 0.523 L·gDOM. 0.325 L·gDOM obtained was of banana peel, 0.487 L·gDOM of mandarin orange peel and 0.462 L·gDOM of methane from kiwi peel. Research shows that this kitchen waste is a very good raw material for methane production.