Research by AeroThermal Group showed that 635kWhr of renewable electricity can be generated from one tonne of fast food waste while one tonne of household kitchen waste generated 847kWhr.
The company looked at how fast food restaurant waste can be processed using a combination of autoclaving and anaerobic digestion to generate renewable electricity.
The experiments examined the potential biogas yield from both types of waste separately, which allowed assessments to be made of the potential yield from a plant processing varying fractions of waste.
The AeroThermal process is particularly well suited to waste of this type because it can break down paper and card into a form that can be digested anaerobically to create biogas.
Tests on the kitchen waste fraction showed that virtually all of it can be converted into a digestible ‘floc’ after a small amount of plastic packaging had been recovered. Similar tests on the fast food showed that about 80% could be converted into a digestible floc.