Community-Based Management of Household Solid Waste for Harare, Zimbabwe: A System Dynamics Approach

Abstract

Community-based waste management (CBWM) is a waste decentralization approach that carries the potential to divert about two-thirds of household solid waste (HSW) from landfills. Although many studies have suggested this approach to waste management in the city, assessment studies to quantify its material recovery potential are yet to be conducted. This is the gap this study thus aimed to fill. Due to the complex nature of the HSW management system, the study used Network Analysis (NA) findings to inform the development of a system dynamics model. The model was used to assess household level composting of food leftovers as well as paper and plastic recycling as strategies towards sustainable and integrated HSW management in Harare. A CBWM strategy implementation chart (CBMWSIC) that describes four different strategy implementation levels and their potential benefits for Harare if implemented over a 5-year municipal period (2022-2026) was formulated. According to the author’s knowledge, combining NA and SD techniques as done in this study is original work. 

Hereafter only referred to as Harare, urban Harare currently realizes an average recycling rate of 5.2% (recycled waste as a percentage of the total HSW generated in the city). However, composting all food leftovers and recycling of 50% paper and plastic in the next municipal period of 2022-2026 is likely to increase it to 34.1%, 41.6%, 51.8%, and 63.1% with each level of strategy implementation. On the other hand, uncollected waste will be reduced by 28%, 55.9%, 55.9% and 62.3%, respectively. Illegally dumped waste is potentially reduced from 224 854tons.yr-1 to 186 009tons.yr-1, 178 496tons.yr-1, 147 440tons.yr-1, and 112 866tons.yr-1, at each implementation level respectively. Controlled waste treatment in the city will also be increased by up to 38.3%. Generally, composting food leftovers is better prioritized in High-Density (HD) and Medium-Density (MD) suburbs, where food waste comprises 33% of the HSW generated. Since HD suburbs carry most of the city population, recycling paper and plastic is also better prioritized here. Overall, Harare can achieve better recycling rates when mixed strategies are applied.