Performance and Durability of a Gravity Charcoal Filter for Organic Pollution

Confronting the health emergency posed by the organic pollution of Lake Kabongo for the city of Kolwezi, this study proposes a frugal and circular innovation: a gravity filter designed on the principle of resource economy and the use of local materials. The objective is threefold: performance, optimization, and durability to address the polluting load (TOC and COD > 12 mg/L) affecting a population of over 600,000 people. The filter, structured around accessible media (gravel, sand, artisanal activated carbon from coconut shells and lemon juice), was subjected to a rigorous experimental design testing six different layer assemblies. The data reveal optimal performance for a three-layer architecture (5/50/35 cm), achieving a reduction of approximately 52% in COD and TOC parameters. Turbidity decreased from 20.8 to 6.6 NTU, bringing it closer to the WHO standard, without significant pH fluctuation. Beyond efficiency, a multicriteria analysis (Pivot Table and Radar Chart) demonstrated that this configuration offers the best balance between purification efficiency and resilience, minimizing clogging risks. More than just a treatment process, this filter embodies a sociotechnical solution rooted in its local context, offering a sustainable, economical, and ecological alternative for securing access to safe water.