Engineers In Indonesia Turn Trash Into Treasure

By: Marie McCarthy

Nutritionists often tell us that “food is fuel”. Engineers also agree. A team of Indonesian researchers is working on turning vegetable and fruit waste into energy sources for use in urban cities by using a wet torrefaction process.

Solid waste collection and disposal is a big issue in Indonesia with a lot of moving pieces. So is energy security. Currently, Indonesia is part of the 80 percent of the world that relies on fossil fuel energy sources. Climate scientists predict those resources will be exhausted in 50 years or less.

Indonesian scientists decided to kill two birds with one stone by using municipal solid waste to power their home country. And they wanted to find the best way to do it. Their goal is to eliminate growing municipal waste and repurpose it as alternative energy. Big cities like Jakarta, Bandug, Semarang, and Surabya have rapidly growing populations and as a result, increasing amounts of waste. Much of it is put into landfills but other trash ends up burned, discarded into rivers or stored in the soil.

These scientists wanted to reduce the amount of discarded trash and fossil fuel use by utilizing trash. In the experiments, city dweller trash became treasure. They collected trashed leaf litter, vegetables, fruit, and food and tested each under wet torrefaction methods of varying degrees.

Biomass torrefaction is a chemical process that changes properties to enhance fuel quality during combustion and gasification. Torrefaction is typically between 200 to 320 degrees Celsius. Researchers tested each kind of biomass under temperatures of 150, 175, 200 and 225 degrees Celsius and held each for 30 minutes to produce energy yields of 58 percent.

The results of their experiments show that food waste torrefaction actually increases yield when the calorific value is increased.  These conclusions differ from other wet torrefaction processes and indicate high energy potential for food waste in Indonesia.

To read more about the study, click here.

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