Quantification and valorization of compost derived from urban households’ waste in Bukavu City, Eastern D.R. Congo

Abstract

This study focused on quantifying and valorizing domestic waste in Bukavu, a rapidly growing city in eastern Democratic Republic of Congo (DRC). With increasing anthropogenic pressure, waste management has become a pressing issue, yet documentation in this area is still limited. This study aimed to fill this gap by providing comprehensive data on domestic waste generation, composition, and disposal practices in Bukavu city. Through field surveys and analysis, waste quantities and types were documented, revealing significant challenges in waste management infrastructure and practices. Additionally, the study explores opportunities for waste valorization, particularly through composting, given the region's agricultural potential and growing urban food demand. The findings revealed that ~ 5% of the domestic waste is biodegradable, with the majority consisting of metals and plastics. These wastes are predominantly used as livestock feed (10%), incinerated (66%), or buried (17%), with ~ 5% undergoing composting. Waste management is primarily handled by children (82%), with very few non-governmental organizations (NGOs) involved in such activities. Among the three composting methods evaluated, outputs from vermicomposting demonstrated superior qualities in terms of promoting crop growth, increasing yield, and achieving a high germination index. Overall, the application of composts improved plant growth and yield parameters of the two major legumes (common bean and soybean). Future interventions should explore the implementation of large-scale composting units at the household or citywide level, while also considering additional strategies to enhance the quality of the compost products. Such efforts are crucial in mitigating the environmental and health impacts of urban household waste and promoting sustainable practices in urban agriculture.