Life Cycle Assessment of Waste Utilizations from Dairy Farm

Dairy farming is one of the main sources of greenhouse gas emissions. The study aims to compare the environmental sustainability performance of dung, urine, and wastewater utilizations to reduce GHG emissions in dairy farms and raw milk production. Life cycle assessment has been conducted using the ReCiPe midpoint impact assessment method. The comparative assessment results are divided into four cases: (1) base case: waste storage in open lagoon, (2) sludge separation for liquid and organic fertilizers production, (3) anaerobic digestion for liquid and organic fertilizers production and (4) anaerobic digestion to generate electricity and heat in conjunction with the production of fertilizers. The results revealed that using waste to produce electricity and heat (Case 4) resulted in the lowest impact on the environment. The impacts on climate change, terrestrial acidification, freshwater eutrophication, water consumption, and fossil depletion could be reduced by about 20%, 87%, 89%, 15% and 23%, respectively, as compared to the base case. The greenhouse gas emission of milk production under the case 4 would be about 909 kg CO2 eq per ton of fat- and protein-corrected milk (FPCM). Recommendations to enhance efficiency of the dairy farm waste’s utilization are discussed.