Plastics Recycling

Over 30 major (large-volume) family types of plastic are produced commercially today. The two major groups are thermoset plastics (which cannot be recycled) and thermoplastic polymers (which can be recycled). A smaller, but growing, category includes those derived from biomass. Most of the products from this category are derivatives of cellulose or modified starch. Recently, two new families of plastics derived from corn, polylactic acid (PLA) and polyhydroxyalkanoates (PHA) have been developed and are being used to replace hydrocarbon-derived thermoplastics in a variety of applications.

This report covers the following thermoplastic families:

• Polyethylene terephthalate (PET), a polyester resin
• Polyethylene (HDPE, LDPE, HP-LDPE, LLDPE)
• Polypropylene (PP)
• Polystyrene (PS); expandable polystryene (EPS) is the primary polystyrene recycled
• Polyvinyl chloride (PVC)

The increasing global substitution of plastics for other types of materials will keep plastic waste in the public spotlight for many years. The unrelenting introduction of new plastic packaging materials with unique compositions tailored to provide superior performance characteristics for specific applications will contribute to the increasing technical complexity of plastics recycling. The continued use of new materials, mixtures of materials and a diversity of container shapes will create new challenges for mechanical recyclers, making it more difficult and expensive for collectors and processors to match their output to available markets while creating new markets.

Commodity thermoplastic resins are unique among commonly used materials in their ability to be recovered and recycled. In this report, recycling is defined as including mechanical (physical) recovery, chemical (depolymerization to monomer) recovery, thermal (pyrolysis to basic feedstocks) recovery and incineration with energy recovery. Although the chemical and pyrolysis processes have the potential to be very attractive recovery routes that eliminate many of the technical and quality limitations encountered with mechanically recycled plastic resins, they are not being used extensively globally. However, the cumulative effect of plastics recycling on the global consumption of thermoplastic resins has been negligible in terms of virgin resin displacement. Part of this is due to new markets being developed for recycled materials. It will take wider institution of recycling technologies that essentially produce "virgin" resin (e.g., chemical depolymerization) before virgin resin displacement occurs.

Energy recovery and recycling are complementary. Communities with waste-to-energy (WTE) facilities typically extract recyclable materials such as plastics, paper and glass before sending nonrecyclable wastes to the WTE facility. Studies in the United States, Canada and Europe have shown that communities with WTE facilities often have a higher total diversion rate from landfills and a correspondingly higher mechanical recycling rate. Single-stream recycling, whereby plastics and other post-use materials are commingled, then collected and sorted by a materials recovery facility, allows communities to collect more materials for recycling and energy recovery diversion options based upon local needs. Each energy recovery facility employs 50–60 full-time employees, while improving energy security and protecting the environment.

Postconsumer PET is the most recycled plastic globally, with a developed recovery infrastructure in developed nations. Postconsumer HDPE is the second-most-recycled plastic in the world. Combined, recycled PET and HDPE account for nearly 99% of the global bottle recycling capacity, and nearly 70% of total postconsumer plastics recycling. 

China currently produces 85% of the world's recycled PET fiber. Chinese capacity to convert rPET to polyester fiber more than tripled from 2002 to 2007. China is the final destination of 70% of the world's plastic waste. China is estimated to have recycled 8 million metric tons of domestic plastic waste in 2007. Despite this massive figure, very little information is available on plastics recycling in China. China put a ban on imported postconsumer plastic bag and film waste in 2007. 

Globally, the plastics recycling business is still largely regionalized and located primarily within centers of high population density for feedstock acquisition. Achieving a balance between supply and demand for recycled plastics is critical to the longer-term viability of regional collection programs. High transportation costs for low-bulk-density plastic material dictates the economic boundaries of feedstock acquisition. Local/regional granulation facilities have been evaluated as a way to offset the high freight costs of baled plastics.

Collection of plastic recyclables will continue to be one of the most important challenges facing the global plastics industry. The passage of new legislation dealing with the recovery and reuse of plastic waste has slowed. To strengthen the collection infrastructure, additional legislation may be needed to provide more consumers with an economic incentive to recycle.

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