Biopolymer Waste in Spain

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Francesc Giró of the Catalonia Waste Agency was concerned that the desertification now occurring in southern Europe needed to be corrected by adding massive amounts of organic matter to the soil, and this required more composting infrastructure.  In reality 70% of waste organic matter in the region is still land-filled or incinerated and action was needed to allow this to be collected separately and composted.  The target is to compost 50% of organic matter by 2020 and in Catalonia a tax on landfill and incineration is encouraging movement in this direction.

• ·         Door to door collection of food waste is required.
• ·         Compostable bags need to be used for this collection.
• ·         Disposable nappies were a huge problem, accounting for 2.5% of all waste.
• ·         Compostable diapers could make a large contribution to compost production, but they were currently twice the price of the petro-diapers.

Judit Janasa of TOMRA Sorting and Recycling commented on the difficulties of separating mixtures of plastics containing biopolymers but concluded that their sorting machines would soon be able to remove compostable bioplastics from the recycling stream.  They have installed 3470 sorting machines worldwide, mostly in the Iberian peninsula.  These machines use electromagnets, high intensity visible light, infra-red both transmitted and reflected, X-ray, atomic density, and laser fluorescence sensors to identify different materials.

The machines are tuned to the key wavelengths reflected or transmitted by each polymer and digital images taken at these wavelegths are analysed pixel-by-pixel so that for a bottle for example, the cap, label and body polymers are identified and recorded.  Problems arise with black polymers (no reflection), and labels made of paper prevent the underlying polymer being seen.  PLA and PET bottles which look identical can be separated easily.  The software in use can be updated for every new polymer once samples have been tested.

Asked how multilayer bottles or films would be treated, Ms Janasa said the majority polymer would take precedence.