Reimagining the milk supply chain: Reusable vessels for bulk delivery

Milk packaging has been analysed multiple times in pursuit of finding the most appropriate vessel from an environmental point of view. Research has concentrated on commercially available containers of 0.5 – 2.5 litres, usually made from High-Density Polyethylene (HDPE), Polyethylene Terephtalate (PET), paper-based cartons, or glass, with some studies considering a reuse scheme for glass bottles. Whilst applicable for household delivery, such a reuse scheme is not practical for delivery to cafés where large volumes of milk are used every day; little information is known about transportation of bulk volumes of milk in bigger vessels such as steel churns. This study compares a proposed milk supply chain using a mix of reusable stainless steel churns and reusable glass bottles with the current supply chain that uses single-use HDPE bottles, for transportation of milk to 10 cafés belonging to The University of Sheffield. A cradle-to-grave life cycle assessment (LCA) is conducted using data obtained from the university and Our Cow Molly, a local dairy farm which delivers milk to the university. Sensitivity analysis was performed around the recycling rate of plastic bottles, water consumption for churn cleaning, the reuse rate of glass bottles and churns and the source of the on-farm electricity. The study suggests that the greenhouse gas emission can be lowered by approx. 6.5 tons of CO2 equivalent annually if the reuse scheme is applied (this equates to a 65% reduction for the processes analysed). Considerable savings are also reported in categories such as water consumption, fossil resources depletion and cumulative energy demand. The reuse scheme is, however, likely to induce a similar or higher mineral resource use and higher environmental damage in the marine eutrophication category due to water treatment. Production of plastic bottles in the plastic scenario and maintenance and transport on the reusable side are the main contributors to the environmental impact. Further improvements in the reuse scenario could be achieved by reducing the amount of water used for cleaning and hence the electricity demand for water heating. The reuse scheme could also benefit environmentally from using an electric refrigerated van instead of a diesel vehicle.