New routes for treating food waste could unlock bioenergy potential

A review of how food waste is treated indicates that combining anaerobic digestion and pyrolysis could lead to better recycling of waste material.

14 January 2020

Muriel Cozier

The growing global population is leading to an increase in food waste and recalcitrant organic residues (ROR) which come from food waste treatment plants.

Of the methods available for dealing with food waste which include landfill and incineration, anaerobic digestion is considered to be the most sustainable and economical for resource recovery. Anaerobic digestion with the aid of biological microorganisms can convert food waste to products with additional value such as fertiliser. However, the ROR generated in the anaerobic digestion process is typically assumed to be of no use and often disposed of using incineration or landfill. Pyrolysis has been found to provide a better outcome when dealing with ROR, particularly for plastic waste where three products: gas, oil and a solid residue (char) have potential for further recycling.

In a review published in SCI journal Energy Science & Engineering, researchers in China found that integrating anaerobic digestion and pyrolysis presents a useful route for the sustainable use of food waste and ROR, but there is currently little information on how these technologies combine. Current research combing these two technologies in one of three ways: anaerobic digestion/pyrolysis, pyrolysis/anaerobic digestion or anaerobic digestions/pyrolysis/ anaerobic digestion, indicates that such an approach could be useful once careful consideration has been given to the waste being treated.

Reviewing the routes for treating food waste and ROR, researchers found that each one presented its challenges. However, combining anaerobic digestion and pyrolysis provides a possible route for using the inherent bioenergy potential of food waste and ROR.

Energy Science & Engineering DOI: 10.1002/ese3.503

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