Pollution with contaminants from effluents of industrial units constitutes a danger to health and environment. This is the case of chromium (Cr) and formaldehyde [CH₂O (H−CHO)] contained in leather tannery effluents, identified and characterized by ICP-OES (Inductively coupled plasma - optical emission spectrometry) and HPLC (High Performance Liquid Chromatography). The levels recorded for these two contaminants in wastewater constitute an environmental risk of average degree. The treatment of this wastewater by electrocoagulation completely eliminates chromium and reduces organic pollution by 65%. We applied an electric current (I) of variable intensity (1 to 2.5 Ampere). The best results were obtained with the highest current intensity.