Recycling plastics

Consumption of plastics in Western Europe is predicted to grow by 12 million tonnes (from 24.9 million tonnes to 36.9 million tonnes) between 1995 and 2006, which represents and annual growth rate of approximately 4 per cent. Within this, consumption of polypropylene terephthlate (PET) is predicted to grow most rapidly. An increasing number of medium and long-life plastic products (for example building and construction products, automotive components and electrical and electronic goods) will reach end-of-life over the period 1995-2006 and therefore post-use plastics waste will increase slightly more quickly relative to plastics consumption. Overall, plastics waste is increasing at a greater rate than plastics recycling.

In Western Europe in 1995, plastics make up about 1% by weight of total wastes and 7% by weight (20% by volume) of domestic solid waste. The amount of waste generated in 1995 represented 64 per cent of processors' total plastics consumption. By 2006, this is predicted to increase to 69 percent.

Currently, most plastics recycled in Europe arise in distribution wastes. Plastic recycling remains relatively difficult. According to the Association of Plastics Manufacturers in Europe (APME), 7.4%, or 1.1 million tonnes of plastic wastes arising in 17 West European countries were recycled in 1991. Furthermore, in 1992, almost one quarter, or 3.5 million tonnes of all plastic waste in Western Europe received beneficial usage at the end of its first life.

Recycling plastics is mainly done by mechanical recycling and incineration. In member countries of the UN Economic Commission for Europe, an average of 8% of post-user plastics are mechanically recycled and 17% are incinerated (though often without energy being recovered). Mechanical recycling of plastics in West European countries include: 80,000 tonnes of bottles in 1993 within the European bottle scheme; 23% of plastics used in transportation in 1992; an increased plastics recycling rate of 36,000 tonnes for the automotive industry in 1992; and 14% of plastics waste in the agricultural sector. APME further estimates 16% of Europe's plastic waste was recovered in 1992 by turning it into usable energy via incineration. Incineration reduces the amount of plastic wastes not suited to recycling and otherwise in landfill sites.

The main constraints to improving recycling rates are: (1) the imbalance between the waste collectable and the potential end-markets for the recycled plastics, for example recycled plastics are not suitable for the broad range of food contact applications; (2) the presence of large quantities of mixed plastics waste where the difficulties and energy consumed in separating into homogenous fractions and cleaning outweigh the environmental gain of mechanical recycling. Certain types of post-use waste (small, lightweight and dirty) require more energy to collect, sort and recycle than is saved).

In addition to recycling limitations, there is an upper limit to potential demand for mechanically recycled plastics. One supermarket chain turns its distribution packaging into in-store packaging, producing carrier bags. This saves an estimated 1000 tonnes of plastics or one million gallons of oil per annum. Another supermarket recycles its distribution film into in-store plastic bags and saves 5 million gallons of oil a year. Feedstock recycling is a relatively new method for plastic recovery. In Germany, one company feedstock recycles 40,000 tonnes of plastics waste per year.

Both mechanical and incineration recycling methods tend to be costly; moreover mechanically recycled plastics are usually dirtier and lose some of their strength in comparison to the material they were made from. These drawbacks have led to alternative recycling methods, particularly chemical or feedstock recycling. Feedstock recycling breaks down the long chains of hydrocarbon polymers that plastics are composed of with heat, pressure, chemicals, or all three. The resulting length of the chain, controlled by the process, defines its chemical characteristics and permits the chains to be reused as feedstock for the production of a broad range of chemicals, including the same plastic polymers they started as. Many methods of chemical recycling have been used, including hydrolysis, glycolysis, methanolysis, transesterification, hydrogenation, and electrokinetic gasification, though the technology is still at an early stage of development.

More than 20 industrial companies and research organizations are involved with chemical recycling of plastics. For instance, in November 1994, five companies in Europe formed a plastics-to-feedstock recycling consortium that is going to invest about US$6 million in a pilot plant. Their recycling process breaks down several plastic polymers at the same time, avoiding costly sorting of plastics into single polymers before recycling. Furthermore, a sand filled fluidized bed reactor traps solid contaminants, such as metal fillers, producing cleaner end-products, and incineration of the waste gas is expected to make the process energy self-sufficient.

In 2000, the Brazilian government cut the tax rate on recycled plastic from 12% to 5%. Before it was more highly taxed than virgin resin (subject to 10% tax). The cut will help the competitiveness of recycled plastics. In 1999, the recycling rate for plastics was 15% or 200,000 tonnes per year; and for PET was 25%, or 67,000 tonnes per year.

In North America, carpet manufacturers could consume more PET plastic waste than is available.