King Mongkut researchers turn food waste into a form of charcoal

Headed by Dr Trairat Muangthong-on, the KMUTT team’s technique turned bread leftovers, vegetable leftovers and fruit peel into a so-called “biochar”.

Biochar is a charcoal-like product that contains no petroleum. It is made by heating biomass.

Trairat said his team collected food waste within the university and isolated the bread, vegetables and fruit peel for the research.

The team then used the pyrolysis method and a fixed-bed tube reactor to turn the food waste into biochar. The experiment controlled the temperature and amount of nitrogen for about an hour in each pyrolysis process.

Pyrolysis is the thermochemical decomposition of organic materials at elevated temperatures, typically in an absence of oxygen. That is, the organic material is heated up in a closed container without any oxygen present. The resulting solid fuel had a high composition of carbon comparable to low-grade coal.

This demonstrates that food waste could be used as a low-cost fuel for factories, Trairat said.

The technique could be applied to reduce the disposal cost of food waste while also generating a low-cost fuel for industries.

Trairat said the breakthrough could be adopted by government agencies in their push for sustainability.

For example, the Energy Ministry, the Interior Ministry, the Pollution Control Department, and private firms can apply the technique to reduce the cost of fuel while managing food waste at the same time.

Trairat said his team has carried out the study after food waste has been a major issue both in Thailand and around the world.

The UN Environment Programme reported that in 2019 there was over 931 million tonnes of food waste around the world, and the Pollution Control Department reported that there were 9.68 million tonnes of food waste in Thailand in 2022.

Trairat said his team would next research how to turn other types of food waste into biochar and would try applying the technique with waste at factories making sugar from sugarcane and at animal food factories.