Waste wood processing routes. Possibilities and environmental evaluation by means of mLCA

CE Delft conducted a study on post-use wood processing routes for the Ministry of Public Works and Water Management (Rijkswaterstaat). The report focuses on:

  • existing and emerging processing techniques by type of wood;
  • the costs of wood processing;
  • an environmental comparison of forms of processing wood waste.

The possible processing routes of released wood are depicted in a visualisation.

The environmental analysis was conducted according to the principle of ‘multi-cycle LCA’ (mLCA). This involves consecutive processing multiple times. All the routes of processing wood can lead to a net environmental benefit: the impact for processing is then lower than the impact of producing a similar product from virgin raw materials. In recycling, achieving environmental benefits depends on the use of renewable energy, the environmental impact of auxiliary materials used (binders, recycling auxiliaries) and on the type of virgin product that has been avoided.

Cascading wood makes environmental sense. Reusing wood, then recycling and only then possibly burning it brings more environmental benefits than directly burning the wood. This applies to all the environmental impacts studied, but especially to land use. In terms of climate impact, cascading is even more favourable if long-term storage (decades) of biogenic CO2 is also realised and included.

Burning wood releases the biogenic CO2 that was stored in the wood. This means that to counter the greenhouse effect it makes sense to delay, or even completely avoid, combustion for as long as possible.