LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

GROUP 2, SESSION A: CARBON OR WATER FOOTPRINTS, SOIL, BIODIVERSITY 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
66. Water footprint of milk at dairy farm
Armelle Gac 1,* , Sindy Moreau 1 , Didier Moreau 2 , Samuel Vionnet 3
1 Institut de l'Elevage, Building and Environment Department, BP 85225, F-35652 Le Rheu, France, 2 Danone
Dairy Division WorldWide, Environment Direction, F-75000 Paris, France, 3 Quantis International,
Parc Scientifique EPFL, Bat-D, 1015 Lausanne, Switzerland, Corresponding author. E-mail: armelle.gac@idele.fr
The water resource preservation is becoming a new challenge for agriculture at local and global scales. It is
assessed through water footprinting, an emerging methodology. The Water Footprint Network was a precursor
for defining a water footprint methodology (Hoekstra et al. 2011) and provides figures focusing on livestock
productions (Mekonnen & Hoekstra, 2012). The WFN methodology focuses only on specific types of
water flow whereas the WULCA project of the UNEP SETAC LCA Initiative (Koehler & Aoustin 2008) and
the future ISO 14046 Water footprint (under development) support that water footprinting should follow the
same framework as LCA (ISO 14040 and 14044).
This study presents an application of the water footprint to dairy farms, adapted from Ridoutt and Pfister
(2010). This stress-weighted water footprint is based on an assessment of the amount of freshwater withdrawn,
consumed water and grey water generated by the production activity (Figure 1). A regionalised characterisation
factor, the water stress index, is then multiplied with the inventory to obtain the Water Stress
Assessment (WSA) (Figure 2) that reflects the potential for water uses to contribute to water scarcity.
This method has been tested in collaboration with Danone in 3 farms in 3 different countries (Spain, Poland
and Saudi Arabia). The functional unit is to produce one kg of whole milk, at the farm gate. The physical
flows of water inside the system were described to identify the different sources of freshwater use and consumption
(withdrawal water, consumed water). The four main sources (Fig. 3) gather the animals (drinking
water, transpiration of animals, water in milk and evaporation from manure), crops and pastures (irrigation
and evapotranspiration of plants), the milking parlour (washing and evaporated water) and the farm inputs
(diesel, electricity, fertilisers and off-farm feed production). Concerning the flows occurring on the farm
assumptions, references and models were used to assess the water requirements and losses. Data about the
farm inputs for different countries were provided by databases (ecoinvent v2.2, Quantis Water Database,
access December 2011). The Grey water is calculated for the whole farm, based on N leaching potential.
Only nitrogen is considered assuming that generally the quantity of water needed to assimilate produced
nitrogen will be enough important to assimilate produced phosphorus as well as other pollutants.
The preliminary results show the importance of off-farm processes, especially feed production, on the total
WSA of the milk. It occurs that the options for farmers to reduce the water footprint of their products would
focus on decreasing the use of some inputs. Nevertheless, the consideration of physical flows at farm level
remains important for appropriation of results by the farmers and also because actions to reduce water footprint
can be more easily undertaken at this level than at the supply chain level. The study also underlines the
fact that some methodological issues have to be improved: characterisation of the withdrawal water and assessment
of the grey water, as well as implicit weighting of consumed water with grey water.
References
Hoekstra AY, Chapagain AK, Aldaya MM, Mekonnen MM. 2011. The water footprint assessment manual:
Setting the global standard. London: Earthscan. p 203
ISO 14040: 2006. Environmental Management - Life Cycle Assessment - Principles and Framework
ISO 14044: 2006. Environmental Management - Life Cycle Assessment - Requirements and guidelines
Koehler A, Aoustin E (2008) Assessment of use and depletion of water resources within LCA. SETAC
Europe, Warsaw
Mekonnen, M.M. and Hoekstra, A.Y., 2012. A global assessment of the water footprint of farm animal products,
Ecosystems, doi: 10.1007/s10021-011-9517-8.
Ridoutt, B., Pfister, S., 2010. A revised approach to water footprinting to make transparent the impacts of
consumption and production on global freshwater scarcity. Global Environmental Change 20, 113-120.
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