This is an implication from Waste & Resources Action Programme (WRAP) research into the use of such sorting systems.
While MRF capacity will need to be increased in line with recycling ambitions, a worry is the fact that many facilities deal with one or few streams.
Looking at North America and Europe, it found that much larger facilities of between 50,000 and 100,000 tonnes per annum capacity were operational which could handle a wider range of materials.
WRAP ROTATE manager Linda Crichton said: MRFs with the ability to handle material from multiple collection routes, material collected differently and integrating non-commingled would provide more flexibility.
At the moment, many are designed to process specific materials and when these take other materials it can cause problems. But the MRF must segregate and ensure the value of what goes in is maximised.
The current situation makes quality a bigger issue and more recent contractual arrangements are charging back the cost of dealing with contaminants to the local authority rather than the MRF operator.
This had led to some performance-based contracts with set levels of non-recyclables, but WRAP believes there needs to be a greater degree of interaction towards matching local authority collection needs with MRF capabilities.
MRF design needs to consider how to handle material from a number of different collection schemes, with some local authorities presently having to shop around or only collect what the MRF dictates.
More effort is also required from the local authorities to improve and maintain the level of commingled collections and take more interest in the standard achieved at MRFs with incentives needed, added Crichton.
Waste contracts can last as long as 25 years and some question how responsive to change current facilities are and how much emphasis is given to the available infrastructure at the tender stage.
After positive feedback from workshops, WRAP is currently taking stock and looking at how to take the debate forward.