Groundwater quality decline is a major constraint on drinking-water supply in several localities of Casamance (Senegal), where well water often shows physico-chemical characteristics incompatible with World Health Organization (WHO) drinking-water standards. This study evaluates the effectiveness of activated char produced from “ditakh” (Detarium senegalense) shells, chemically activated with either lemon juice or phosphoric acid (H3PO4), for treating well water in the Kandé and Lyndiane neighbourhoods of Ziguinchor. Samples were collected over four months from four wells (two per neighbourhood) and characterised in situ (pH, electrical conductivity EC, TDS). The chars were then tested using two setups: direct char-water contact and multilayer bed filtration (sand, limestone, activated char). Results show high acidity and mineralisation in the raw waters, with occasional exceedances of the WHO conductivity guideline (1300 μS/cm). Activated-char treatment significantly improved pH and lowered conductivity, with an optimum obtained at 30 g of lemon-juice-activated char for Kandé water and 4 g of H3PO4-activated char for Lyndiane water. The H3PO4-activated char, being more porous, showed a higher adsorption capacity than the lemon-juice-activated char. Multilayer filtration incorporating two sand layers gave the best purification performance. These results confirm the potential of ditakh shells as a local, available and low-cost precursor for producing activated char for household water treatment.
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