Waste sorting is the process by which waste is separated into different elements. Waste sorting can occur manually at the household and collected through kerbside collection schemes, or automatically separated in materials recovery facilities or mechanical biological treatment systems.

 

One solution for automatic sorting is based on infrared spectroscopy, using ordinary halogen lamps as light source. In the selected range of infrared wavelengths, objects have different reflection properties than for ordinary visible light. This is advantageous as the computer can distinguish between plastic-coated cardboard, ordinary cardboard and different kinds of plastics by small variations in the "colour" of the reflected infrared light. The human eye, however, can detect only the visible colour of the objects.

 

The reflection at the various infrared wavelengths is recorded continuously as the waste crosses a transverse sensing line of the conveyor belt. The data is sent to a computer, which analyses the readings and constructs a two-dimensional image of the debris on the conveyor. Based on this analysis, the computer identifies the location of the different elements in the waste on the conveyor and directs jets of pressurized air to blow e.g. the beverage cartons into a container, while the rest of the waste continues to another conveyor.

 

Contact XenICs to find an optimal solution for your waste sorting application.