'Wet Waste' Could Lead to 165% Decrease in Aviation Emissions

Unlike production methods for other biofuels like ethanol or biodiesel, the new approach uses a new chemical process to efficiently remove excess water from the "wet waste."

By manipulating the chain length of the carbon molecules in the "wet waste" — which can include food scraps and human waste — the researchers generated short-chain and medium-chain carboxylic acids. These are precursors for biofuels known as "volatile fatty acids" (VFAs).

They then used a process called ketonization to "elongate the carbon backbone of the VFAs." This process created paraffin-rich hydrocarbons and isoparaffin-rich hydrocarbons that can be used for jet fuel. 

A 'circular manufacturing process'

As an Inverse report reads, the scientists propose a circular manufacturing process with their new fuel method. Essentially, human waste from lavatories aboard planes will be collected to help power future flights.

The paper's authors argue this process has the potential to account for 20 percent of the U.S.'s jet fuel consumption, bringing it closer to its goal of carbon neutrality.

This is another great example of an initiative that tackles two global issues at once: food waste accounts for 6 percent of greenhouse emissions worldwide. Combined with other forms of "wet waste," including human excrement, and animal manure, these byproducts have the potential to vastly change the aviation industry.

In laboratory tests, the new fuel was shown to have minimal impurities and chemical leftovers from the waste that would not be useful for fuel. More research is needed, though companies such as Boom Supersonic, who aim to launch a fleet of supersonic carbon-neutral airliners, will no doubt be looking on from the sidelines.

Editor's Note 17/03/21: The title of an earlier version of this article incorrectly stated that "human waste" could lead to a 175% reduction in aviation emissions. This was changed to more accurately reflect the original statement from the authors of the study.