Food waste to biofuels developments offer hope for when we don’t eat it all

Parents may tell their kids to eat all the food on their plate, we may know all the lyrics to Weird Al Yankovic’s “Just Eat It” satire song, or even watched the movie about foods waste called “Just Eat It,” but according to the Food and Agriculture Organization of the United Nations, food waste is still a huge issue globally with roughly one third of the food produced in the world for human consumption every year – approximately 1.3 billion tons – gets lost or wasted. Maybe because we don’t want to “just eat it” or because it spoils easily, fruits and vegetables, plus roots and tubers have the highest wastage rates of any food.

It’s not just on the consumer end where the food waste occurs, but the production and retailing parts of the supply chain as well. The FAO chart below shows the per capita food losses and waste, at consumption and pre-consumptions stages, in different regions.

For years, researchers and companies have been looking at how to convert food waste to biofuels and useful products. With each new innovation, we get a step closer to utilizing something destined for landfills as a valuable product.

Most recently, in Massachusetts, chemical engineers at Worcester Polytechnic Institute (WPI) developed an improved process that transforms waste food into biofuel. Their method improves the yield of oil from the waste food conversion process while also improving efficiencies using catalysts to the hydrothermal liquefaction.

Michael Timko, associate professor of chemical engineering, said his process could become an economical way to transform food that has spoiled or is being otherwise discarded into biofuel to power schools, restaurants, grocery stores, and even entire communities. He said he envisions reactors that would permit businesses and institutions that sell or serve food to process their waste to generate a liquid fuel they could use to generate power, saving money and helping the environment. And, he said, by keeping waste food out of landfills, where it decomposes to produce greenhouse gases and water pollution, the process will have significant environmental benefits.

The science

According to WPI, Timko and his team added catalysts to the liquefaction reaction to see if they could reduce the amount of carbon compounds lost to the water phase and increase the yield of oil, thus making the process more efficient and economical. They experimented with two types of compounds: sodium carbonate (Na2Co3), a homogeneous catalyst, and a group of heterogeneous catalyst known as cerium-zirconium mixed oxides (CeZrOx).

Although sodium carbonate did not significantly increase the yield of oil, adding CeZrOx did (from under 40 percent to over 50 percent), while reducing the amount of compounds remaining in the water phase. “By adding these catalysts, we have been able to increase the yield of biofuel and decrease the loss of compounds to the water phase by 50 percent. A 50 percent change is very promising,” said Timko.

In ongoing research, the team is investigating other potential catalysts, including red mud—a waste created during the production of aluminum, which is inexpensive, stable, and reliable. The project was funded by a one-year, $168,373 SBIR grant from the U.S. Department of Energy.

Food waste to biofuels innovations abound

While the latest WPI discovery is another step in the right direction to utilizing some of that food waste, using food waste to produce biofuels is not new. The Digest reported about it as far back as 2010 and in 2015 we reported on food waste statistics and “The Food Waste Debacle.”

In January 2018, the Digest reported that in Uganda, engineering graduate Lawrence Okettayot is addressing food waste with his new Sparky Dryer, which is a food dehydrator that runs on biofuel from a farmer’s garden and burns with zero-carbon emissions. The dehydrator helps farmers avoid food loss and food waste due to spoilage, which is an issue in Uganda for many farmers. The dryers start at about $80 and can dehydrate 10kg of mango in two hours running on 2kg of biofuel.

In July 2016, the Digest reported that in Singapore, researchers developed a genetically modified a type of Yarrowia lipolytica yeast that can produce butanol from fats in food waste, as much as half the weight of the original feedstock. Ten genes are added to the original yeast to produce the butanol, a process that also reduces CO2 emissions by 75% compared to incineration, requires half as much energy and half as many CO2 emissions as biogasing the food waste would do. Only about 13% of the 785,500 metric tons of food waste produced in the country last year was recycled, which on its own is 30% more than in 2010. About 600,000 tons is incinerated annually.

In the UK, tech startup Entomics started using Black Soldier flies in February 2016 to digest food waste, and two weeks later the flies are ready for harvest. Acting as a conversion catalyst, their bodies produce an oil that can be transformed into biodiesel with protein animal feed and fertilizer as byproducts. Through local entrepreneurial support programs and a partnership with Sainsburys to use their food waste as feedstock, the team of four graduates from Cambridge University are improving the process to get costs down enough to be viable in the market.

Bottom Line

Since so many of us aren’t listening to Weird Al Yankovich’s request to “Just eat it” and retailers don’t want to sell apples that have blemishes, it is apparent that researchers and companies around the world are finding solutions to address the very real global food waste issue. While we can all do things to help decrease food waste in our own lives, we see an even bigger positive impact with new innovations and technologies, like WPI’s, that allow items destined for landfills to be converted into useful biofuel, biodiesel or other valuable products.