A Life Cycle Assessment (LCA) is based on the concept of sustainable development. It provides an effective and systematic means of evaluating the environmental impactsof end-of-life tyres.

Aliapur’s Research & Development department wanted to carry out a Life Cycle Assessment on the various recovery methods for end-of-life tyres (ELT) with a view to addressing three main principles: evaluating the environmental advantages of each of the 9 recovery methods; comparing the environmental impacts generated and avoided by each method; identifying the key points to be observed in the sector’s economic optimisation phase.

The study was started in 2008 and was completed at the end of 2009.

Nine different recovery methods were studied in the context of this research:

• Two recovery methods in public works fields: retention basins and seepage basins
• Two recovery methods in the energy sector: cement works and urban heating
• Five material recovery methods: steelworks, foundries, moulded objects, synthetic turfs and equestrian floors

Some of these recovery methods are destructive methods (cement works, foundries, steelworks, urban heating) and others are non-destructive (retention basins, seepage basins, moulded objects, synthetic floors and equestrian floors).

The evaluation method is based on an LCA approach that is in conformity with the standards ISO 14040/44. It is based on the implementation principles that are the reference in the context of the management of household waste.

Eight environmental indicators were taken into consideration in the context of this evaluation. These indicators were selected because they correspond to the indicators that are the most standard, and recognised as being the most robust in terms of a Life Cycle Assessment. They are also the indicators that appeared to be the most relevant for this sector:

• Total primary energy consumption
• Consumption of non-renewable resources
• Water consumption
• Contribution to eutrophication
• Emissions of greenhouse gases of fossil origin
• Acidifying gas emissions
• Tropospheric ozone formation
• Production of non-dangerous waste

It should be noted that Aliapur has also carried out a wide range of toxicology and ecotoxicology studies since the company started its activities in 2004.

The environmental reviews calculated show that, regardless of the recovery method studied and the impact focused on, the management of end-of-life tyres corresponds in most cases to a significant environmental benefit.

In the other cases, the result was judged to be non-significant but nevertheless showed positive trends. In other terms and for the recovery methods studied, it was always advantageous to invest in the upstream stages that include collection, sorting and shredding/granulation to try and promote the potential of end-of-life tyres.

Comparing the results of the different methods made it possible to identify three main groups:

• The production of synthetic turf, the manufacture of moulded objects and cement works seem to be the most interesting methods for the environmental indicators studied. The advantages of synthetic turf lie essentially in the replacement of a mixture of chalk and virgin EPDM granulate (the production of which requires considerable amounts of energy). The advantages of moulded objects come from replacing polyurethane with ELT granulate. As for cement works, the favourable environmental review comes from the biomass fraction of ELT and the replacement of petroleum coke with end-of-life tyre shred.
• Retention basins and seepage basins are the recovery methods for which the advantages remain relatively minimal. As for foundries, this recovery method is still in its infancy, which is why the advantages are still minimal at present, but were shown to be particularly promising for the future in the medium term (1 to 3 years).
• The other recovery methods showed benefits that were at an intermediary level in relation to the other two categories. Their advantages were more or less marked, depending on the indicators considered.

Every tonne of end-of-life tyres recovered corresponds to savings of:

• Synthetic turf: 70% of the annual energy consumption of an average French citizen;
• Moulded objects: 70% of the annual water consumption of an average French citizen;
• Cement works: 20% of the annual CO₂ emissions of an average French citizen;
• Steelworks: 50% of the annual energy consumption of an average French citizen;
• Urban heating: 10% of the annual CO₂ emissions of an average French citizen;
• Equestrian floor: 50% of the annual water consumption of an average French citizen.

LCA - Reference document (Aliapur, 2010)

LCA - Brochure (Aliapur, 2010)