Gasification does not compete with recycling. In fact, it enhances recycling programs. Many materials, such as metals and glass, must be removed from the MSW stream before it is fed into the gasifier. These are recycled.
Sorting of MSW is undertaken in the processing plant to extract metals, glass, inorganic materials and some plastics, resulting in the increased recycling and utilization of materials. However, not all waste can be recycled, especially plastics.
Thermoset plastics contain polymers that cross-link to form an irreversible chemical bond, meaning that no matter how much heat you apply, they cannot be remelted into new material. Hence, these materials are non-recyclable. Additionally, the same piece of recyclable plastic can only be recycled about 2-3 times before its quality decreases to the point where it can no longer be used and it will end up in landfill. Waste such as multi-layer materials, like coffee cups and wrappers, cannot be easily separated and are difficult and costly to re-process. Other materials cannot be recycled if they contain food residue.
Therefore, even with the best endeavours of authorities and consumers, a large percentage of waste is destined for landfill. Even in countries with best practice recycling methods and with strict waste management strategies, only 31% of plastic waste is recycled. Therefore, in a global ‘best case’ scenario, around 70% of plastics end up in landfill.
These ‘unrecyclable’ plastics prove to excellent, high energy feedstock for Gasification. Thus, we are able to recycle the unrecyclable into green electricity.