Tokyo University researchers Kota Machida and Yuya Sakai have developed a technology to transform food waste into potentially edible “cement” for construction use. It is the world’s first process for making cement entirely from food waste.The tensile, or bending, strength of their product is nearly quadruple that of ordinary concrete, the researchers said.
Machida and Sakai said they hope to help reduce global warming, alleviating problems related to the methane that food waste emits in landfills. Sakai, an industrial science professor, developed the technology while researching sustainable materials that could replace cement-based concrete.
Cement production accounts for 8 percent of the world’s carbon dioxide emissions, think tank Chatham House has said. Sakai first developed a way to make concrete by subjecting pulverized wood particles to heat compression. The three-step process of drying, pulverization and compression was done using simple mixers and compressors that are commercially available.
With his student Machida, Sakai did the same thing with food waste. Previous trials using food waste to make cement required plastics to be mixed in to get the materials to stick together.
After months of failures, they realized they could get the cement to bind by adjusting the temperature and pressure used.
“The most challenging part was that each type of food waste requires different temperatures and pressure levels,” Sakai said. Other experiments in using food waste in construction have mainly focused on using stuff such as coffee grounds or biowaste ashes as filler in regular concrete.
Sakai and Machida said they have successfully made cement using tea leaves, orange and onion peels, coffee grounds, Chinese cabbage and even lunchbox leftovers. They have adjusted flavors with different spices and found that the colors, scent and taste of the cement can be quite appealing.
To be able to eat the material, a person would need to break it into pieces and boil it, Sakai said.
To make the cement waterproof and protect it from being eaten by rodents and other pests, it could be coated with a lacquer.
Food waste is a huge problem throughout the world. Japan produced about 5.7 million tonnes of edible food waste in 2019 and the government aims to reduce that to about 2.7 million tonnes by 2030.
Last year, Machida started a company called Fabula Inc with two of his childhood friends. They are working with other companies to make cups, cutlery and furniture out of food cement.
The process could be used to make edible makeshift housing for people following disasters, Sakai said.
“For example, if food cannot be delivered to evacuees, they could eat makeshift beds made out of food cement,” he said. The food cement can be reused and is biodegradable, so it can be buried when it is no longer needed. “Our ultimate hope is that this cement replaces plastic and cement products, which have worse environmental impacts,” Machida said
