Why do I still have to separate my food waste from my garden waste, in two separate bags, if they are collected together?

Despite these mixed collections, Bruxelles-Propretée insists that Brussels residents should continue to distinguish between green and orange bags. Mixing garden waste and food waste in the same bag would be detrimental for several reasons: 

• Bruxelles-Propreté cannot set its operations in stone and must ensure that it retains a certain degree of flexibility in designating the best collection scheme according to the volume of garden and food waste produced, which varies greatly according to the season.
• While garden waste in the green bag can be "composted" and "biomethanised", this is not the case for food waste in the orange bag, for which only biomethanation is possible. Bruxelles-Propreté must be able to direct garden waste to the composting centre or the biomethanation centre, depending on available capacity.
• Bruxelles-Propreté must ensure that a balanced percentage of garden waste and food waste is sent to the biomethanation centre. Food waste mixed with garden waste in the same bag would deprive Bruxelles-Propreté of this operational arbitration carried out upstream of collection and delivery to the biomethanation centre.