Recovery of Packaging Glass Refuse by Mechanical Biological Treatment Plant- Case Study

It is well known that packaging glass can be considered an excellent example of circular economy due to the characteristics which allow the recycling and reuse without loss of product quality. However, in some countries, the selective collection systems together with campaigns to mobilize the population are not completely efficient and there is still packaging glass in municipal solid waste which is sent to Mechanical Biological Treatment plants (MBT), incinerators or landfills. In a study developed in Portugal it has been found that there is a significant amount of glass sent to MBT which is rejected and currently landfilled. Thus, a diagram was developed to recover the glass refused by MBT for further recycling. The diagram includes magnetic separation, screening, RecGlass (a device developed to separate stones from glass particles) and optical sorting. Using samples from 3 different plants, with glass content between 36 and 60% and different composition and characteristics, the diagram was tested at laboratory and pilot scale. It was possible to produce a glass concentrate with approximately 99% in glass content, with a glass recovery ranging from 24 to 64%.The paper describes the work done and the results achieved.