Recovery & recycling of PET
The EU Packaging and Packaging Waste Directive

The European Union, with the adoption of its Packaging and Packaging Waste Directive, 94/62/EC as amended by 2004/12/EC, is legislating for more effective recovery of used packaging and for the reduction of the impact of packaging on the environment.

a) More effective recovery

Recovery of PET packaging falls under the requirements for recovery and is classed together with other plastic materials in the targets laid down in directive 2004/12/EC:

Overall recovery: minimum 60% of packaging waste Overall recycling of packaging waste (including feedstock recycling): between 55% and 80% Minimum recycling differentiated by material, for plastics 22.5% (including only what is recycled back to plastics)

Member States must meet these targets by 2008, with the exception of Greece, Ireland, Portugal, and the accession countries, which are allowed to delay their attainment.

b) Minimisation of the environmental impact

To be allowed on the market, packaging articles must comply with the following essential requirements:

The content of heavy metals (Cd, CrVI, Hg, and Pb) must be lower than 100 ppm. The use of substances dangerous for the environment must be minimised. The articles must be recoverable by material recycling, organic recycling, and/or energy recovery (at least one of the three). They must be suitable for reuse (when relevant and claimed). The volume or weight of the packaging article must be limited to the minimum adequate amount to maintain the necessary level of safety, hygiene, and consumer acceptance.

c) Status of PET

PET is widely recycled as a material, making a large contribution to the recycling targets required for plastics by the EU directive. When material recycling is not feasible, PET can be incinerated with energy recovery.
Moreover, PET usually does not contain heavy metals and/or substances dangerous for the environment.

The introduction of the PET bottle has created a number of dilemmas, which are currently being resolved slowly by a mixture of political and commercial considerations. The commercial advantages are well understood. However, the traditional use of refillable glass in many northern European countries has resisted the widespread use of the single use PET container that is more prevalent in southern Europe. A refillable PET bottle has been developed and is now used widely in the Nordic countries, Germany, The Netherlands, and Switzerland.
The pursuit of commercial freedom within Europe is a central stone of the EU trade policy, but concerns around unsatisfactory disposal schemes for single use PET containers need to be resolved to the satisfaction of the relevant authorities before complete harmonisation of distribution systems is achieved. In Germany, Denmark, Finland, Norway, The Netherlands and Sweden all beverage containers, single use and refillable, are distributed and collected via a mandatory deposit refund system. Switzerland manages an advanced disposal fee to fund a voluntary collection scheme. The majority of the other European countries are including the collection of PET containers in more comprehensive schemes for separate collection of packaging waste set up to comply with the EU directive.

Recycling of PET containers

PET container recycling is a healthy industry and growing very steadily. Even if the PET consumption rate will follow predictions at around 2.5 to 3.0 million tonnes beyond the year 2007, meeting the EU recycling targets should not be a challenge to the current growth in recycling of approximately 10% pa. Regular information on recovery and recycling of PET can be obtained from PETCORE (www.petcore.org), a European organisation constituted solely to facilitate the recycling of PET containers. Similar organisations are operating on other continents as NAPCOR (www.napcor.com) in the US and the Council for PET Bottle Recycling (www.petbottle-rec.gr.jp/english/en_top.html) in Japan; all offer guidance on recovery procedures.

To assist the overall process of recycling there are guides to good container design and a common specification for collected used PET containers. Sophisticated container sorting equipment, using X-rays and optical sensors, is automated to a level that ensures almost 100% separation of PET from other container types.

There are now clear programmes in place to meet the EU recovery targets and establish recycling of PET as a sustainable process.

PET recovery processes and sustainability

PET can be recovered, and the material reused, by simple washing processes to regenerate clean washed polymer flake (mechanical recycling), or by chemical treatment to break down the PET into oligomers or up to the starting monomers, terephthalic acid and ethylene glycol (chemical recycling). These intermediates are then purified and repolymerised into new PET resins. A final option, for PET that is unsuitable for material recycling (e.g., very dirty, or too contaminated to clean), is to use PET as an energy source.

Purity is essential for good quality mechanical recycling. Discrete physical contamination is usually easy to remove i.e., dirt, glass fragments, stones, grit, soil, paper, glues, product residues and other plastics like PVC and PE. However, ingrained soil caused by abrasion or grinding, for example during baling, transport or handling in poor storage conditions, is difficult to dislodge and will need some filtration to ensure removal. Oils, fats, and greases need more detergents and contaminate wash waters excessively, although leaving no residual quality problems. Chemical contamination occurs by adsorption of contents as flavourings, essential oils, or similar ingredients used in the product formulations. Contamination can also be introduced by consumer misuse of the container for purposes other than the original intention e.g., storage of pesticides, household chemicals, or motor and fuel oils. Complete removal will require desorption, a slow process, hence with reduced productivity. However, these occurrences are few, and are not known to cause many problems during reprocessing. For some low risk applications, like non-food contact and fibres, incidental product contamination is likely to be insignificant. For other uses, appearance and odour are important. The intended use of the recycled PET often determines the feedstock purity requirements.

Chemical recycling processes are generally less sensitive to purity of feedstock than mechanical ones, as they include efficient purification steps.

Recovery of PET by combustion in waste-to-energy power generation plants is a useful method of utilising the high intrinsic energy content of PET (23 MJ/kg, comparable to that of soft coal). If this type of plant is not available, simple incineration is then the alternative option. Combustion of PET is perfectly safe; containing only carbon, hydrogen, and oxygen, with controlled burning its combustion generates only carbon dioxide and water. The volume of ash generated is parts per million, essentially insoluble and can be treated in the same manner as other resulting ashes.

In landfills, PET is stable and inert with no leaching or groundwater risk. Bottles are crushed to very small volume, take up relatively little space, and generally add a degree of stability to the landfill.

Processes for the recovery of used PET

Degree of contamination Recovery process General economics Process convenience Example of feedstocks
Low Washing and remelting Satisfactory Simple Refillable & Single use clear and pale coloured bottles
Medium

Glycolysis

Complete chemical breakdown

Satisfactory

More expensive

Increasing complexity, extra purification technology

Demands larger scale purification plant to reduce costs Fibrous waste, generic PET

Coated and coloured PET, barrier bottles
High Energy recovery as a fuel substitute Well established costs Relatively convenient Laminates, coated and thin gauge films. Very dirty bottles

Uses of recycled PET (R-PET)

Clean, recovered R-PET flake is virtually indistinguishable from virgin PET and can be converted into many different products competing in the same markets. It is used again in bottles for non-food end uses like household chemicals and cleaners. In countries where local laws allow it, the use of R PET for the manufacture of new beverage bottles is growing rapidly.
However, the major secondary use is for the manufacture of polyester fibres then used to make clothing, either directly or as a filling fibre in anoraks and bedding. The fibres are also used extensively for carpets and scouring and cleaning pads. Protective packaging for delicate articles, like eggs, and plants for despatch through the mail, are manufactured from R-PET using thermoforming techniques.

Markets for Recycled PET

Main markets for melt reprocessing of clean recycled PET flake

Fibres
In staple form for fillings e.g., anoraks, bedding, cushions, and furnishings.
Industrial fibres for belting, webbing, scouring/cleaning pads, filters, cleaning cloths, and geotextiles.
Other textiles like carpets, upholstery fabrics, interlinings, protective clothing, and other garments.

Strapping
Binding and strapping tapes, mainly for securing bales or bulky articles on pallets.

Sheet
Blister packaging. Boxes, trays, shallow pots, and cups.

Blow moulding
Primarily into bottles for non-food applications, but its use for food applications is rapidly growing.

Injection moulding
Transparent articles or plates, when reinforced with glass fibre for selected engineering applications.