A team of researchers at Cornell University has discovered a process of turning leftover food into energy much faster than already existing methods. It is a two-step process and is very efficient, since it captures virtually all the available energy.
Other methods work on the basis of anaerobic digestion with bacteria slowly chipping away at the organic matter and producing methane, which is then used for fuel. This new method that the researchers discovered works on the basis of the process of hydrothermal liquefaction. Basically, the food leftovers are first pressure-cooked, which results in a sort of bio-oil. This bio-oil is then refined into biofuel, while all that remains of the original food leftovers is just very watery liquid.
The next step is to feed this liquid into an anaerobic digester, which converts it into methane in a couple of days. Two sources of usable energy are produced via this method, one for generating electricity, the other heat, while none of the original food leftovers go to waste. When using just anaerobic digestion, it can take weeks for the food waste to turn into energy.
Also, the liquefied product that is leftover after the hydrothermal processing in this new method is better for the anaerobic digestion part of the process. Combining the two makes the overall process both more efficient as well as quicker. It takes mere minutes to achieve hydrothermal liquefaction and just a few days for the anaerobic digestion.
Current statistics show that about one-third of the world’s food is wasted, while US landfills are primarily filled with food waste. Needless to say, one of the priorities should be to keep food from becoming waste. But it is also important to find efficient ways of recycling food waste into something useful. A process such as this one, which leaves virtually no waste while producing clean energy would greatly reduce our carbon footprint and lessen our dependence on fossil fuels.