Environmental Impact of Water Use in Life Cycle of Milk Production

Water has a key role in dairy industry and life cycle assessment (LCA) is one of the tools for environmental assessment of products & processes. A cradle to gate assessment of market milk was performed by separating the system into three sub-systems: agronomy, animal farm and processing plant. Data were gathered from multiple sources e.g. published papers, questionnaire, national and international databases, and the processing plant. Throughout the study, ISO framework and IDF guideline on LCA were used. The functional unit for reporting results was one liter of pasteurized milk (2.5% fat) packaged in plastic pouch. Finally, to quantify and assess the environmental impacts from blue water consumption, parameters of a global water impacts assessment model were modified and used in this case study. In production of one FU, about 370 liters of water is needed mostly for feed production. Feed agriculture sub-system alone withdraws 97% of total. Throughout the market milk product chain, about 40 and 28% of total water withdrawal come from alfalfa and barley production mainly from irrigation. In production of one FU, modified model’s estimate for the impact on human health with the unit of disability-adjusted life years (DALY) was about 0.35*10-6, and its estimated value for the impact on ecosystem quality was 0.324 m2*y.