Microsoft Word - Environmental benefits of recycling 2010 update.doc

3.5.2 Comparison between the various end-of-life options

The end-of-life options covered by the selected studies are:

 Various types of composting

 Incineration with energy recovery

 Landfill

 Anaerobic digestion

Table 67 lists all the treatment options analysed. The traditional options are given clearly given more weight
(incineration, landfill and mainly composting), but anaerobic digestion is also studied as a newly popular route.
Unfortunately, no reliable studies have been carried out so far regarding two prominent but not well established
methods, pyrolysis and gasification.

All selected studies focus on the end-of-life stage of food and garden waste; in other words none of the studies
examines the full life cycle of food and gardening.

Table 67 Overview of the end-of-life alternatives compared within each case for food and garden waste

Case Recycling Composting

Incineration

with

electricity

recovery

only

Incineration

with heat or

combined

heat/

electricity

recovery

Landfill

Anaerobic

digestion

Pyrolysis Gasification

1[OR] XX

2[GW1] XX

2[GW2] XX

3[FW1] XX

3[FW2] XX

3[FW3] X* X

4[FW1] X XXX

4[FW2] X XXX

5[OR] XX X

6[OR] X XXX

7[OR] XX

Total number

of cases

010168400

* Scenario assuming total anaerobic degradation

Ranking between the various end-of-life options within each scenario

Study no 1

The first study compared composting to landfill only. Of the four most important indicators chosen, composting is
better according to global warming potential and landfill is bettering terms of primary energy demand. In fact,
landfill is the worst option for all the other included impact categories, except for ozone depletion, where the
difference is only marginal. The fact that the simulated chosen landfill is assumed not to have installed any
energy recovery technologies is decisive for the climate change contribution, since no benefits are attributed to
the landfill option. Therefore, this particular landfill appears a much less attractive option than composting.

Study no 2

The second study compares windrow or home composting to incineration for garden waste and it provides results
for global warming only, out of the basic indicators. Carbon binding is taken into account in this study. In this
impact category, incineration has a better performance than both types of composting. According to the
remaining indicators (eutrophication, acidification, photochemical oxidation, ecotoxicity in water, ecotoxicity in soil
and human toxicity via soil, water and air), incineration is preferable for all but two cases (two for eutrophication
and one case in human toxicity via air). However, the increased energy potential of the garden waste compared