How to recover 90% of waste under favorable economic and environmental conditions?
For lack of alternatives, the waste burial is still too often used by municipalities. The significant distance between landfills and urban centers causes substantial logistics costs that are difficult to bear for most countries’ economies.
In order to limit this burden, the implementation of recovery solutions as close as possible to the production areas, makes also possible the creation of new sub-products that can be marketed locally and generate a real circular economy strategy.
There are generally four main streams of household waste:
· Recyclable materials;
· Organic and fermentable materials;
· Non-recyclable plastics and rubbers;
· Ultimate waste.
To obtain optimal recovery of waste, the overall management plan is based on the following principle:
The first function of a primary household waste sorting center is to separate the different fractions of waste in order to materialize four main flows :
· The organic and fermentable fraction;
· The recyclable fraction;
· The fraction recoverable energetically;
· The ultimate fraction for landfill.
The second step consists in recovering the different recyclable materials separately:
· Plastic films (PE, PP);
· Transparent and colored plastic bottles (PET), part of which will be crushed for recovery in fuel oil within the pyrolysis unit;
· Paper / cardboard;
· Non-ferrous metals.
The thermochemical transformation of waste by pyrolysis / carbonization occurs in few minutes, at temperatures between 450 ° C and 700 ° C, in an oxygen-free environment.
This avoids dangerous pollutants generation such as dioxins, furans, NOx, SOx observed during incineration.
Pyrolysis is an anaerobic transformation process that is environmentally efficient.
This reaction transforms the waste into large quantities of three products: syngas (incondensable gas), pyrolytic oil, and char, which each offer recovery opportunities.