Recycling plastic wastes
Waste management has generated a simple and effective way for environmental protection, the three-Rs guides, namely reduce, reuse and recycle. The first choice is reducing wastes, however, if this is not possible reusing all items is preferable, with recycling being the ultimate solution, whenever wastes cannot be reduced or reused. Due to their features, plastic wastes are hard to reduce or reuse and they are often recycled. Although recycling plastics leads to many benefits, such as air pollution reduction and raw materials conservation, there are still many disadvantages involved in current practices. Thereby, costs related to collection, identification and sorting of plastics are extremely high especially for the involved sorting equipment. Moreover, recycled plastics usually come from specific sources, such as packaging, while possibly only specific types of plastic items, such as PET and HDPE, are recyclable in large quantities. Urged by these requirements, an EC funded project developed an efficient and economical solution for recycling various plastic items coming from industrial and municipal wastes. It combines advanced state-of-the-art spectroscopy identification methods, such as Laser Induced Breakdown Spectroscopy (LIBS) and Infrared Spectroscopy (IR) and uses a hybrid sensor for signal integration. Thereby, extremely accurate sorting rates at high speeds for many types of plastic fractions including PP, PE, PS, PVC, PET and ABS, may be achieved. Prior to sorting, three different sensors are employed to specify and assess polymer, additives and heavy elements in discarded plastics. A complete prototype automatic sorting plant has also been built incorporating processes from feeding and transporting to sorting and plastics excluding processes. Pilot scale trials proved not only the reliability of this plastic recycling technology, but also its economical viability. Suitable for use at recovery centres and plastic recyclers, it is expected to promote plastics recycling to a greater extent.