Microsoft Word - Environmental benefits of recycling 2010 update.doc

Eutrophication

In this impact category, composting appears to have an advantage. Artificial fertilisers are quite intensive for this
impact category mainly because of their high content of phosphorus and nitrogen. The chemical fertiliser saved
because of the use of compost gives important benefits to compost versus the other alternatives. Incineration
mainly and landfilling, in that order, seem to be the worst. For eutrophication, as for acidification, anaerobic
digestion is better than incineration but only in the one available comparison.

Table 78 Ranking of end-of-life options within each scenario for eutrophication

Case Composting

Incineration

with energy

recovery

Landfill Anaerobicdigestion^

1[OR] +++ +

2[GW1] +++ +

2[GW2] +++ +

3[FW1] + +++

3[FW2] +++ + +++ best option

3[FW3] +++ + + worst option

7[OR] + +++ option not assessed

Eutrophication

(kg O 2  eq)

Studies n°4,  5  and  6  do not include this indicator

* Composting scenario assuming anaerobic degradation

Human toxicity

Based on Table 79, it is hard to give an overall conclusion regarding the best option. It is interesting to notice
that landfill and incineration give similar performances when compared. The picture is fairly balanced between
composting and landfill.

Table 79 Ranking of end-of-life options within each scenario for human toxicity

Case Composting

Incineration

with energy

recovery

Landfill Anaerobicdigestion^

3[FW1] + +++

3[FW2] +++ + +++ best option

3[FW3] +++ + ++ intermediary option

4[FW1] + +++ +++ ++ + worst option

4[FW2] + +++ +++ ++ option not assessed

Only studies n°3 and  4  include this indicator

Human Toxicity

* Composting scenario assuming total anaerobic degradation

Key parameters

There are some parameters that have been proved more important than others in an organic waste LCA
framework. The key parameters that have been identified in the selected LCA studies are:

 The electricity mix

 The inclusion of carbon storage and binding

 Material substitution

 Level of technology and relevant efficiencies

Electricity mix

The choice of electricity mix is a key parameter for many organic waste treatment routes and many impact
categories. In the organic waste management system, there are not many processes that are energy intensive.
As a result, whether the electricity mix is based on carbon-intensive fuels (e.g. coal) or not (e.g. renewable
sources) has little influence on the results. However, especially during the past few years, the energy recovery
operations have been embedded in many technologies, such as anaerobic digestion, besides the more traditional
incineration and landfill. Therefore, a significant amount of energy is produced as a result of food and garden
waste treatment. The selected LCA approach determines whether the substitution of energy will follow the
marginal fuel or the average mix. If all recovered energy (which is converted to electricity or heat) substitutes for