Life Cycle Environmental Performance and Improvement of a Yogurt Product Delivery System

摘要

A life cycle assessment was conducted to evaluate the environmental performance of the yogurt product delivery system used by Stonyfield Farm. A life cycle model was developed which included material production, manufacturing and disposition for primary and secondary packaging, as well as the related transportation links between these stages and filling, retail and the point of consumption. Product delivery systems (PDS) that utilized 4, 6, 8 and 32 oz polypropylene (PP) cups and 2oz linear low-density polyethylene (LLDPE) tubes were analysed. Ten strategies for improving the environmental performance of these systems were proposed and their impacts on the total life cycle burden were analysed. The life cycle energy consumption for the 2, 4, 6, 8 and 32 oz containers was 4050, 4670, 5230, 4390 and 3620MJ/1000lb yogurt delivered to market, respectively. Material production of the primary packaging accounted for 58% of the life cycle energy, while Distribution 3 (yogurt delivery to distributors/retailers) alone accounted for one-third of the life cycle total energy. The life cycle solid waste profile showed that as the container size decreased, the solid waste burden increased, from 27.3kg (32 oz) to 42.8kg (6oz) per 1000 lb yogurt delivered to market. This relationship was even more pronounced for the 4oz (47.5kg) and 2oz (56.2kg) product delivery systems. The greatest potential improvements in the environmental performance of the PDS are achievable through redesigning the primary packaging and using alternative manufacturing techniques for the yogurt cups. Shifting from injection moulding to thermoforming of 32 oz container reduces the life cycle energy and solid waste by 18.6% and 19.5%, respectively, primarily due to light-weighting. Elimination of lids for 6oz and 8oz containers provided similar benefits. Consumers purchasing yogurt in 32 oz instead of 6 oz containers can save 14.5% of the life cycle energy and decrease solid waste by 27.2%.