A Decision Support System for Decentralised Waste Utilisation in South Africa

Abstract

Waste valorisation, turning waste into a resource, remains a relatively unexplored and undefined concept in South Africa's historically linear waste economy. This research recognizes the opportunity for sustainable business development within this space, specifically through decentralised waste utilisation driven by mall, medium and micro enterprises (SMMEs). In response, this study introduces a novel Waste Utilisation Decision Support System (WUDSS), a five-tier process aiming to optimise various influencing parameters such as financial, social, technical, legal, environmental, and risk-based considerations. A mathematical modelling framework was created to describe the WUDSS, consisting of two parts, namely the Process Calculations as well as the Integrated Optimisation Model. To evaluate the framework, a problem domain was identified. Seven feedstocks were selected based on the highest waste production quantities in South Africa, and a final shortlist of 40 waste conversion and end-product production processes were included in the WUDSS. Financial modelling was employed to analyse potential project viability. A prototype of the WUDSS was created, verified, and validated against historical projects, literature, and case studies. The verification of the system demonstrated a high level of accuracy, with 94% of technical outputs and 82% of financial data falling within required ranges. Further verification was achieved through three case studies, all closely matching actual results. Finally, verification of the Integrated Optimisation Model was achieved by exact match with the first principle calculation outputs. Thus, the WUDSS proved to be a valuable tool for decision-making in decentralised waste management in South Africa, contributing to the discourse on industrial ecology and circular economy.