Environmental Impact Assessment of Low-Density Polyethylene and Polyethylene Terephthalate Containers Using a Life Cycle Assessment Technique

In the present study, the life cycle of two milk packaging containers (Polyethylene terephthalate PET and low-density polyethylene; LDPE) was assessed with an emphasis on different product-life scenarios in Iran. The functional unit was adjusted to work on one ton of plastic milk packaging containers. The system boundary included all life cycle stages, including resin production, packaging production, collection, transportation, and waste management (mechanical recycling, landfill, incineration). In the production sector, the resin was produced from raw materials and mechanical recycling was defined as producing granules from milk packaging containers. The granules obtained from recycling were used in the production of fruit baskets and disposable agricultural irrigation pipes. The first waste scenario included 10% recycling, 80% landfill, and 10% incineration. The second scenario consisted of 50% recycling, 20% landfill, and 30% incineration. The third scenario had 65% recycling, 10% landfill, and 25% incineration. Input data included using resources (water, raw materials), energy (electricity, fuels), and all emissions based on the function unit. The impact categories consisted of global warming, ozone depletion, fuel consumption, and toxicity to humans. SimaPro 9 software was run and the IMPACT + 2002 assessment method was employed to assess the environmental impact. According to the findings, the recycling process performed better than the landfill and incineration processes in all scenarios. The third scenario was determined as the most beneficent one in waste disposal of the two containers. In all effective categories, except air pollutants, the life cycle impact of PET was greater than that of LDPE. Furthermore, the life cycle impact of PET was greater than that of LDPE in all phases of the cycle except transportation.