With the revised Waste Framework Directive due to come into force on 12 December 2010, EU Member States are busy planning how to deliver the requirements set out in the directive.It is clear that the collection method and the choice of and expansion of infra-structure for sorting and reprocessing will be critical for the requirements to be achieved.
Collection can be based on one bag for everything or separated streams for different materials. The Waste Framework Directive sets out a preference for separate collection but other means can be chosen If it is technically, economically and environmentally practicable to achieve the necessary quality standards.
Based on the example from Belgium, Sweden and Germany it is clear that good results can be achieved with different systems. However, it is important that the collection, sorting and reprocessing are complementary.
So what are the infrastructure options available to EU Member States when they embark on their diversion of plastics from landfill crusade?
Material Recovery Facility (MRF) is a sorting technology traditionally used for metal, glass and paper but can also handle plastics if appropriately designed. This technology sorts recyclates into their components for further reprocessing elsewhere.
An MRF residual stream will typically leave non-sorted material which is either used for Energy from Waste or disposed of in landfill. The residual plastics in such stream provide significant part of the caloric content for waste incineration without which fuel will have to be added.
Autoclave (or Mechanical Heat Treatment) is an alternative technology to treat unsorted municipal Solid Waste (MSW). It treats MSW with steam under pressure to produce material which can be sorted into type and then directs it to recycling or recovery.
This process leads to more plastic being recoverable from the MSW but requires further reprocessing for use as a secondary raw material. Plastics sorting is required for mixed plastic rich streams such as separate kerb side or bring station collection. The rapid technology development in sorting plastic allows smaller and more pieces of a particular plastic (e.g. PP, PS or PVC) to be sorted individually from a mixed plastic stream.
A plastics recovery facility (PRF) is suitable to further refine the plastic stream from an MRF or an autoclave. Besides sorting plastics into separate types, sorting systems will sometimes reprocess the material by cleaning and homogenizing the material so it is suitable as alternative feedstock to virgin plastics.
Whilst some countries – like Germany – have already a significant PRF capacity, other Member States rely upon foreign providers of this service. Generally more capacity is needed across the EU.
As with an MRF, it is not possible for all plastics to be sorted into separate types. However, the residual stream is an excellent input for feedstock recycling or potentially used for solid recovered fuel (SRF).
Mechanical Biological Treatment (MBT) is a technique to treat MSW after sorting out targeted recyclables by drying and partially removing the easily degradable components. The output from such technology is approximately halved in weight, dry and with a higher calorific value than the MSW and can be reprocessed into Solid Recovered Fuel (SRF).
Significant amounts of difficult-to-recycle waste streams are turned into this specified fuel across the EU if the quality limits can be met. It is suitable for co-combustion replacing fossil fuel in cement production or for power and heat generation as well as being used with bio mass. SRF has huge potential and plastics play a key role because of their high calorific content.
