Researchers at Cornell University have discovered this new process to generate energy from food waste that is much more efficient than previous methods.
About one-third of the world’s food – nearly 1.3 billion tons – is lost or wasted. For all industrialized nations, food waste accounts for roughly $680 billion annually. In addition, composting and digestion of food waste are inefficient and slow.
Currently energy is sometimes extracted from food waste using anaerobic digestion where bacteria slowly break down the organic matter over many weeks and the resulting methane is captured and used as fuel.
The Cornell researchers have shown that by using hydrothermal liquefaction before the anaerobic digestion, virtually all of the energy is extracted from the food waste. In the hydrothermal liquefaction process, which only takes a matter of minutes, the waste is basically pressure cooked to produce a crude bio-oil. That oil can be refined into biofuel.
The remaining food waste, which is in a watery state, can then be anaerobically digested by microbes within days. The microbes convert the waste into methane, which can be used to produce commercial amounts of electricity and heat.
Combining hydrothermal processing and anaerobic digestion is more efficient and faster than current methods.