Waste treatment is divided into material, energy and thermal recovery.
In material recycling, the waste is broken down into its material components and re-used.
Energy recovery involves using waste with high energy values as a replacement for standard fuels to generate electricity and heat. Thermal treatment is a form of energy recovery. Waste incineration plants are a classic example of this. Waste, for which no other treatment is worthwhile from an economic and ecological perspective, is incinerated and at least the process heat is used.
In fermentation, the organic material is used for both material and energy recovery. The digestate is returned to the cycle as a natural fertiliser, and the biogas can be used as a renewable energy source. As a result, fermentation of organic waste is the most valuable and sustainable form of recovery.