Reprocessors struggling with surge in mixed plastics recycling
The rise of mixed plastics collections in the UK is starting to pose serious material quality problems for reprocessors, according to new research out today (January 30).
According to a technical guide from WRAP, increasing amounts of mixed plastic packaging are diluting the presence of PET and HDPE bottles, making it difficult for plant operators to extract these polymer types to a high enough standard.
The cost of this fall in quality in turn is now being passed onto local authorities through a reduction in the price they receive for their plastic bottles, and this trend is likely to continue until more infrastructure capable of sorting bottles from mixed plastics comes on-stream.
The study points to a gradual shift in the market due to the rise in non-bottle plastics within plastic bottle grades. Feedback received from reprocessors suggests that around half of all recovered plastic bottles and the bulk of mixed plastic plastic packaging are currently exported.
In addition, reprocessors are warning that some materials recycling facilities (MRFs) are contributing to the problem due to the higher levels of non-bottle plastics and other materials such as paper and glass in their outputs.
That said, more modern MRFs are capable of sorting plastics into different categories, including PET-rich and HDPE-rich products. In theory this level of separating should replace some of the necessary bottle sorting capacity that is required.
However, reprocessors claim that these materials are rarely sorted to a high enough standard without being sent through the entire plastics sorting process first at a specialised plastics recovery plant. As a result, the additional premium attached to these materials is arguably higher than their worth.
On a technical front, the lack of capacity to sort to the standards required is further hindered by economics - mainly the cost of sorting lower-value materials such as mixed plastics in the UK compared with lower reprocessing costs abroad.
The report points out that while plastic bottle collections in the UK have increased dramatically over the past decade, capture rates are still relatively low. Collection figures currently stand at over 280,000 tonnes in 2010 - with a recycling rate of 48.5% - compared to less than 13,000 tonnes in 2000 (recycling rate 13%).
However the low capture rates remain a cause for concern. In 2009-10, 87% of UK households had access to a kerbside collection service for plastic bottles with some offering additional services for non-bottle rigid plastic packaging such as pots, tubs and trays, and others offering mixed plastics packaging including films.
While there is no consistent view among reprocessors on what local authorities should be collecting, some argue that councils should carefully consider the consequences of introducing a mixed plastics collection, or allowing plastic bottle-only services to drift towards more of a mix.
The study emphasises that recycling capacity directly affects capture rates and therefore must be a key consideration for local authorities. To help tackle the problem, good communication is required throughout the recycling chain whereby feedback from reprocessors can reach contractors, the authority and householders.