Water consumption
This impact category was only examined by one study (no 3) and the results show a preference for composting
over landfill. In fact, in all three cases included in that study composting was clearly superior, as Table 75 below
indicates.
Home composting in study no 3 is examined through both artificial anaerobic (case FW2) and artificial fully
aerobic (case FW3) conditions. Both systems perform similarly for all indicators but climate change. Therefore,
cases FW2 and FW3 have the same value for water consumption. The centralised compost (case FW1) requires
twice as much water as home composting, but it is still much better than landfill.
In this impact category, the production of secondary material enabled by composting is the decisive factor that
separates the results of composting and landfill. The use of compost on land and the substitution of cow manure
(in study no 3) leads to some irrigation savings that landfill cannot produce.
Table 75 Relative difference between the impacts from the different end-of-life options vs. composting for water consumption for organics. A
positive value means that composting is preferable to the other end-of-life option. A negative value means that composting causes a larger
environmental burden than the other end-of-life option.
N° case 3[FW1] 3[FW2] 3[FW3]
Landfill 150% 380% 380%
Only study n°3 includes a comparison with composting for this indicatorComposting versus other
alternatives*
- Composting scenario assuming total anaerobic degradation
3‐175%
‐150%
‐125%
‐100%
‐75%
‐50%
‐25%
0%
25%
50%
75%
100%
125%
150%
175%
Relative difference with composting according
to the number of cases
>150
%
<‐ 150
%
>150%
<‐150%
composting
preferred to
alternativealternative
preferred to
compostingWater consumptionLandfillFigure 40 Relative difference between the impacts from the different end-of-life options vs. composting for water consumption for food and
garden waste. The size of the “bubble” is proportional to the number of cases coming up with a value within the same range as another.