3.3.5 Comparison with the results from the previous report edition
The review conducted in 2006 covered 60 scenarios and compared recycling, incineration and landfill. The plastic
types studied were the same than in the present study (PVC, PP, LDPE, HDPE and PET), except for PS (which as
not included in the 2006 review).
Among the selected scenarios in this 2006 edition, the choice of the ratio of material substitution for recycling
differed from one scenario to another, and thus the influence of this parameter could be analysed. For scenarios
that anticipated recovered material to substitute virgin material of the same kind in the weight/weight ratio of 1:1
(assumptions chosen by the studies selected in the present review), closed-loop recycling was found to be
environmentally better than both incineration and landfill on all environmental impact categories, with recycling
being 50% better on average. This is thus in line with the results obtained here. In addition, the authors could
demonstrate that a ratio of 1:0.5 (1 kg of recycled plastics replace 0.5 kg of virgin plastics) was about the break-
even point at which recycling and incineration with energy recovery were environmentally equal.
The previous study also pointed out that the possible needs for washing or cleaning prior to recycling of plastics
containing organic contaminants may lead to incineration being environmentally preferable to recycling. Among
the studies selected for the present review, this issue was only investigated in study no 2. However the results
did not highlight the influence of this specific parameter.
3.3.6 Data gaps/further research......................................................................................
Key parameters
As the possible washing and cleaning needs prior to recycling were only considered in study no 2, this issue could
not be specifically investigated in the present study. However, as highlighted in the previous report edition, the
recycling environmental performances can be affected by the need for cleaning, for example in the case of plastic
packaging containing residues such as shampoo or ketchup. As the residues are mainly organic, the washing step
can give rise to a significant COD (Chemical Oxygen Demand) load in wastewater. The energy requirements to
treat the COD reduce the environmental benefits from recycling. Conversely, the organic content is an advantage
for incineration thanks to the heating value of the contaminants.
Coverage of the various end-of-life alternatives
The comparison between recycling, incineration and landfill has been conducted on a significant number of cases,
since on average 20 cases were included for each of these alternatives. On the other hand, pyrolysis was
included in only two studies and in view of the obtained results, it would be interesting to be able to confirm the
environmental benefits of this option by other studies.
Environmental indicators
As in the case of paper, the climate change potential clearly stands out as the indicator that draws more
attention. The number of cases including water consumption is too restricted to be able to make general
conclusions. The lack of interest in the water consumption indicator is probably linked to the fact that washing
and cleaning was not included in the studies. However, it would be advisable to include this issue in the
assessment.