Rediseño del sistema de tratamiento de aguas residuales para la Curtiembre “Moyolsa” de la ciudad de Ambato.

Abstract

The present degree work set as objective to redesign a system of treatment of residual waters of the tannery "Moyolsa"; for this, it was defined specifically to effluents of unhairing and tanning that contain sulfur and chromium respectively, its characterization showed parameters of biochemical oxygen demand (BOD5), Chemical Oxygen Demand (COD), Total Solids, Sedimentary Solids, Sulphides and Sulfates for unhairing, Trivalent Chromium and Hexavalent for Tanning that exceed the maximum permissible limits, thus the unhairing biodegradability index was calculated in 0.417 and for tanning 0.166, defining a biological and/or physical-chemical and physical-chemical treatment respectively, therefore an aeration was performed for the unhairing in order to oxidize sulfides, obtaining a concentration of 600 ppm of manganese sulphate for a period of 6 hours while in the tanning water, coagulation and flocculation was done to precipitate the Chromium, obtaining optimal coagulant concentrations of 15 ppm at 100 rpm for one minute and flocculant of 0.5 ppm at 20 rpm for 15 minutes followed by its resting for 3 hours. As a result, the final characterization of the treated water obtained a percentage of removal of 88.57% of S-2, 90.79% of Cr6 + and 98.34% of Cr3 +; and although they have not entered into current environmental norm, their efficiency was verified by achieving a reduction in chromos and sulfides, in addition pollutants are considerably reduced. Therefore, 2 units were sized, a settler to specifically treat waters containing chromium (acidic pH) and an aerator to oxidize waters with sulfides that are incorporated into the current water treatment to optimize the system. It is recommended the water recirculation for skin wash and the training of operational management for efficient treatment of the proposed redesign of tannery effluents.