Dec 15, 2017

Process developed for ‘dry’ digestion of solid waste into biogas

A scientist in Sweden has developed a process for the dry digestion of organic waste into biogas in two different types of reactors.

According to a statement from the University of Boras, doctoral research student Regina Jijoho Patinvoh’s research results reveal that a simple reactor of textile materials works well in dry digestion of solid waste such as chicken feathers, citrus peels and manure. Apparently, the microorganisms that breakdown the waste eventually adapt to the dry material so the process speeds-up.

“In another type of reactor, a tube-like plug flow reactor suitable for continuous processes where waste is continuously fed, it is possible to shorten the digestion time as long as you feed the right amount of material", said Regina Jijoho Patinvoh. "I have investigated the limits for the optimal amount of material."

Development of the textile reactor

The reactor was developed by the textile company FOV Fabrics in collaboration with the University of Boras. According to Patinvoh, it is suitable for the small-scale production of biogas, for example in developing countries.

"This reactor is small, light, and you don't need expert knowledge to use it. Just feed the waste mixed with a bit of digestion sludge and zip it up. The biogas production will start, causing the reactor to swell up like a balloon. The gas is let out through a hose. When there's no more gas coming out, you take out the residue and feed with more waste."

Typically, water is an important component of the process to turn organic waste into biogas. This is an obstacle, meaning biogas production requires high energy and water consumption, and results in a lot of residues. Patinvoh’s research could well address these issues.

“This makes it possible for households, neighbourhoods or societies to extract their own biogas which they can use for running their stove or use as electricity. At the same time rid of a lot of their waste.”