A circular economy model for organic waste management in a South African eco-tourism reserve

Abstract

This dissertation presents the design, contextual adaptation, and validation of a circular foodwaste valorisation model tailored for the Kalahari Reserve, an isolated eco-tourism and conservation site in the semi-arid Northern Cape region of South Africa. The research addresses a dual operational challenge prevalent in remote reserves: the substantial cost associated with importing food and the environmental challenges posed by organic waste disposal. The study employed the Design Science Research methodology, advancing through iterative phases encompassing problem identification, artefact development, contextual adaptation, and empirical validation. The artefact is composed of three interdependent subsystems: livestock feeding, bokashi fermentation, and horticultural production, that collectively form a decentralised circular supply chain, transforming organic waste into food, compost, and animal feed. Pilot studies focused on bokashi processing and livestock feeding, yielding coefficient data crucial for model calibration. Quantitative validation was performed using Statistical Process Control (SPC), regression analysis, scenario testing, Material Flow Analysis, and Circular Value Stream Mapping to evaluate process stability, yield reliability, and system synchronisation. Key performance indicators were deployed to assess circular outcomes. The model demonstrated a waste-diversion rate of 100%, a conversion rate of 100%, a resource-efficiency ratio of 0.99%, and a secondarymaterial substitution rate of 53%, achieving an overall System Performance Index (SPI) of 93%.The findings affirm that the artefact achieves mass-flow closure, operational stability, and high circularity under arid conditions, illustrating that decentralised circular-economy interventions are both viable and potentially transferable within similar conservation contexts. This study makes a significant contribution to the domain of Industrial Engineering by integrating Lean and Circular principles through the combined application of Material Flow Analysis (MFA), Circular Value Stream Mapping (CVSM), and Key Performance Indicator (KPI) frameworks. Additionally, it establishes a methodological framework for engineering-based circular-bioeconomy models in the Global South, thereby facilitating localised sustainability transitions in ecologically sensitive and resource-constrained settings.