The current national expanded polystyrene (EPS) collection systems are burdened by two main problems: high transportation cost and low quality of the recycled polystyrene.

Transport
The low freight density (volume to weight ratio for EPS) causes high transportation cost. In orde to reduce the volume some EPS collectors already use grinding mills to reduce the volume, achieving a reduction by factor 2-3. A further compression can increase this to a factor of 10. From central regional collection places the compressed material is transported to processors, where it is re-extruded to low-grade polystyrene, or it is directly exported to the Far East.

Quality 
EPS waste is mainly collected from the construction and packaging industry. Construction EPS contains brominated flame retardants. Both types of EPS look alike and one has to assume that both are processed without separation at the collection places.

The major part of the collected EPS is incinerated or used in Poroton^® tiles and cement flooring. These applications require only a low purity of the recycled material and the market value is low. High demanding applications like injection moulding and re-expandable polystyrene require a very low degree of thermal degradation and a high purity. Conventional processes can only achieve this in very exceptional cases.

Compressing and re-extrusion lead to thermal degradation of the polystyrene and additionally flame retardants can form brominated toxic reaction products.

Poroton^® is a registered trademark of the German Association of Poroton Manufacturers