Access to drinking water remains a major concern in the Democratic Republic of Congo, particularly in the city-province of Kinshasa where the populations are confronted with the optimal management of water points, the insufficiency of hygiene and sanitation, the low drinking water supply rates and the lack of appropriate water disinfection methods at the family level. Therefore, the integration of biological processes for the treatment of river water could be a sustainable alternative in improving the quality of drinking water, due to the availability and non-toxicity of the substances used. This study aims to test the effectiveness of M. oleifera seed powder in purifying the waters of the Kalamu River. The methodology adopted consisted in the treatment of water samples from the mentioned river by coagulation-flocculation with M. oleifera seed powder coupled with filtration on fine sand associated with charcoal. The procedure began with the preparation of the colloid solutions. To do this, each of the three different doses (0.5 g/l, 1g/l and 1.5 g/l) of M. oleifera seed powder was mixed with 100 ml of water from said river. Then, each solution of the colloids was added to 900 ml of water sample to be treated. After mixing and a rest period, the treated water samples were filtered. To assess the effectiveness of this process, the physicochemical parameters (turbidity, pH, dissolved oxygen, ammonium, nitrates, nitrites, phosphate, COD, BOD5, electrical conductivity and total hardness) and microbiological (E. coli, Faecal streptococci and total Coliforms) of the treated water were evaluated after the filtration step. For all the treated water samples, the best dose was 0.5 g/l of M. oleifera seed powder because it significantly improved all the parameters analyzed up to the potability standards prescribed by the WHO.