Today, food waste, agricultural waste such as manure as well as sewage sludge, are treated in an anaerobic digestion process for the production of methane or biogas. The aim of the project is to change the current digestion process from producing a single product to a biorefinery where many different products can be produced. By dividing the process into several steps with the new technology, it is possible to access valuable volatile fatty acids.

Building blocks for new products

Mohammad Taherzadeh, Professor in Bioprocess Technology, who leads the project, explains:

"Biogas or methane is an important renewable substance. However, the methane gas formed in the digestions process has a low commercial value, as the methane must be refined to act as biofuel for vehicles, for example. Therefore, we are now looking at whether we can extract volatile fatty acids, which in turn can be used as building blocks in many different production areas such as food, animal feed, pharmaceuticals, textiles and plastics."

Combines two techniques

The project will develop a platform for extracting the valuable volatile fatty acids. This platform will then be combined with membrane bioreactors. With the new technology, the aim is to extract as much valuable fatty acids of as high quality as possible, before they will be converted to methane. Several different configurations for the membrane bioreactor must be developed and used to be able to extract the volatile fatty acids from different kinds of combinations of waste. Examples of products that can be developed with the fatty acids as building blocks are butanol, which is used as a solvent, for example, in perfume, varnish, shellac, resin, rubber and dyes, PHA (a kind of bioplastic) and fungal biomass, which can be used as animal feed.

The project is funded by the Swedish Research Council and runs until 31 December 2022. It is carried out in collaboration with Lantmännen Agroetanol and the Belgian company VITO, which develops membranes and separation processes.

Read more

Read more about the project.

Read more about research in Resource Recovery.

Text and photo: Solveig Klug
Translator: Eva Medin