RESUMO
In recent times, many investigators have delved into plastic waste (PW) research, both locally and internationally. Many of these studies have focused on problems related to land-based and marine-based PW management with its attendant impact on public health and the ecosystem. Hitherto, there have been little or no studies on forecasting PW quantities in developing countries (DCs). The key objective of this study is to provide a forecast on PW generation in the city of Johannesburg (CoJ), South Africa over the next three decades. The data used for the forecasting were historical data obtained from Statistics South Africa (StatsSA). For effective prediction and comparison, three-time series models were employed in this study. They include exponential smoothing (ETS), Artificial Neural Network (ANN), and the Gaussian Process Regression (GPR). The exponential kernel GPR model performed best on the overall plastic prediction with a determination coefficient (R2) of 0.96, however, on individual PW estimation, ANN was better with an overall R2 of 0.93. From the result, it is predicted that between 2021 and 2050, the total PW generated in CoJ is forecasted to be around 6.7 megatonnes with an average of 0.22 megatonnes/year. In addition, the estimated plastic composition is 17,910 tonnes PS per year; 13,433 tonnes PP per year; 59,440 tonnes HDPE per year; 4478 tonnes PVC per year; 85,074 tonnes PET per year; 34,590 tonnes LDPE per year and 8955 tonnes other PWs per year.
RESUMO
Recently, the issues of land-based plastics and their associated challenges in the marine world have been widely publicised in the media and scientific literature. Thus far, despite these communications, there have been few reports that have focused on the issues that acute plastic waste generation and its poor management pose to human health and the global environment. Also, articles on ways to mitigate these issues particularly in sub-Saharan Africa have not been documented. Indeed, there is significant scope for improvements in plastic waste management in developing countries, which offer a wide range of economic and environmental benefits. Plastic waste generation in sub-Saharan Africa is dependent on many factors like urbanization, etc. Currently, the population of sub-Saharan Africa is around 1 billion as of the year 2019, the amount of generated waste is 180 million tonnes at the rate of 0.5% per capita per day, the amount that is openly dumped is 70% and the plastic waste generated annually is 17 million tonnes. Therefore, this study aims to provide an overview of the plastic lifecycle and problems associated with plastic waste management in sub-Saharan Africa, including current practices, public participation and opinion, and government regulations. In addition, this highlight aims to outline the impact of plastic waste proliferation on man and the environment; and the economic and environmental benefits of proper plastic waste management. Critical discussion of current processes and the suitability of potential solutions provide the basis for proposition on mitigation measures to avert the negative impact of plastic waste.
