Abstract
The world, including South Africa, is facing a plastic waste challenge due to the growth of plastics production and usage. Plastic waste pollution has negative social, economic, environmental, and human health impacts. This study is an environmental life cycle assessment (e-LCA) study that sought to inform sustainable options for managing plastic waste in South Africa, using the City of Johannesburg as a case study. Five plastic waste management scenarios were developed informed by plastic waste management policies and processes and current practices from different countries, including South Africa, reviewed from literature together with South Africa's waste management goals and field observations. Scenario 1 considered the landfilling of all generated plastic waste; scenario 2, which represented the current situation, involving the combination of 54.3% landfilling and 45.7% mechanical recycling; scenario 3 entailed 31.1% mechanical recycling, 27.3% landfilling and 41.6% incineration with energy recovery; scenario 4 involved 45% mechanical recycling, 15% landfilling, 20% incineration with energy recovery and 20% gasification, while scenario 5 comprised of 50% mechanical recycling, 8% incineration with energy recovery, 20% gasification, and the use of 22% plastic waste as solid refuse fuel (SRF) in a cement kiln.
These scenarios were assessed for their life cycle impacts using SimaPro 9.1.1 software by PRé Sustainability and the Ecoinvent Database. The ReCiPe 2016 v1.04 endpoint method, Egalitarian version, was used to calculate the impact potentials. A sensitivity analysis was done to test the robustness of the model. Some of the main impact categories assessed were: Global Warming, Marine Ecotoxicity and Human Toxicity. Damage assessments on human health, ecosystems, and resource depletion and subsequent single score results showed the superiority of scenario 5 over other alternative scenarios. Single scores were 76.4 MPt for scenario 1, 15.3 MPt for scenario 2, -16.8 MPt for scenario 3, -31.3 MPt for scenario 4 and -40.7 MPt for scenario 5, indicating an overall negative impact on the environment for scenarios 1 and 2. This e-LCA study showed that the current plastic waste management practices in South Africa are environmentally unsustainable and therefore can be improved by moving away from landfilling.