The assessment of the feasibility to valorize basaltic dust as flocculants additives in order to improve the sedimentation and dewatering characteristics of drinking water sludges was outlined as general objective in this research. The experimental study was divided in three stages: (1) sampling and physicochemical characterisation of basaltic dust (colour, density, oxides content, electronic microscopy, etc.), (2) optimisation of the coagulant dose applied in the coagulation-flocculation process by using of the basaltic dust as flocculant and (3) physico-chemical characterisation of sludges produced in jar tests using basaltic dusts and raw water. The physicochemical characterisation of the basaltic dust (Corrosivity, Reactivity, Explosiviness, Toxicity, In flammability and Biological Risk) showed that this material was not a hazardous waste. Density, oxides content and particle size values of this material were similar to those reported for activated silica (a conventional inorganic flocculant). Basaltic dust improved sedimentation rate, filtration time and specific resistance to filtration from 2 to 5 times with respect to the values obtained for those experiments carried out without dust. The basaltic dust also reduced 60 % the coagulant dose (decreased from 25 to 10 mg/L Al-2(SO4)(3)), employed in order to meet the Mexican standards for drinking water.
