Industrial wastewater discharged in the city of N’Djamena (Chad) contains substantial concentrations of heavy metals and alkalinity-related ions that threaten aquatic ecosystems and public health. This study evaluates the efficiency of a low-cost biosorbent prepared from peanut (groundnut) husks for the simultaneous removal of five heavy metals ions (remove metal ions such as Pb²⁺, Cd²⁺, Cu²⁺, Zn²⁺, and Cr³⁺,) and three alkalinity-related base cations (calcium, potassium and sodium) from three real industrial wastewater samples collected in N’Djamena. Batch adsorption experiments were carried out using acid/base-washed peanut husk powder of controlled particle size (200–300 µm), and metal concentrations were determined by atomic absorption spectrophotometry (ISO 8288) before and after treatment. Removal efficiency (RE, %) was calculated for each element, and a Tobit regression model was applied to properly account for left-censored (below-detection-limit) measurements, while a linear mixed-effects model assessed the combined effects of treatment and metal type on concentration, with sample included as a random effect. Chromium showed the highest removal efficiency among the heavy metals (80.8%), followed by cadmium (68.9%) and lead (55.0%), whereas zinc and copper displayed strongly negative removal efficiencies (−513.3 % and −158.3%, respectively), indicating a net release of these elements from the adsorbent matrix. Among the alkalinity metals, sodium was efficiently removed (81.5%), while calcium and potassium concentrations increased after treatment (−215.3 % and −38.9%, respectively). Tobit regression confirmed that the initial concentration was the only statistically significant predictor of residual concentration (β = 0.2588, p < 0.001), regardless of metal type (p > 0.05). These findings demonstrate that peanut husk behaves as a selective, low-cost biosorbent, particularly effective for chromium, cadmium, lead and sodium, but that further optimization of dose, pH and contact time is required to limit the release of zinc, copper, calcium and potassium into treated water.