Microsoft Word - Environmental benefits of recycling 2010 update.doc

Table 66 Materials included in the selected LCA studies

Study Case Material

11[OR]Organic municipal waste

2[GW1] Garden waste

2[GW2] Garden waste

3[FW1] Food waste

3[FW2] Food waste

3[FW3] Food waste

4[FW1] Food waste

4[FW2] Food waste

55[OR]Organic municipal waste

66[OR]Organic municipal waste

77[OR]Organic municipal waste

2

3

4

Besides these seven studies, an Australian study was located focusing on comparisons between different types of
composting (Recycled Organics Unit, 2007). Although it is a valuable study that penetrates the compost systems
quite comprehensively, it was decided not to analyse it further since it includes no other treatment options and
thus relative conclusions.

The clear definition of the system boundaries when performing an LCA is essential for appreciating the
assumptions and methodologies included, as well as for understanding the type of comparisons among treatment
routes. The system boundaries are unique for each study and all particularities should be taken into account
when reviewing. A general framework of a typical (usual) system boundaries diagram is illustrated below in
Figure 33.

Agriculture

production

Water

Fertiliser

Gardening

Food

production

Post‐consumer waste

Incineration Landfilling Anaerobic Digestion Composting

Collection

Disposal & recovery

Avoided

fertilizer

production

Avoided energy

production

Alternative use

of incineration

capacity

Carbon

sequestration

/ storage

Application of

compost on

land

Material production

and use

Electricity

Heat/Stream

Co‐products

Marginal

material Electricity

Heat/Stream

Co‐products

Marginal

material

Ratio of

“down‐cycling”

per component

Consumption

Figure 33 The food and garden waste system and key parameters