Rediseño del sistema de tratamiento de aguas residuales de la Curtiduría José Laura de la provincia de Tungurahua.

Abstract

The objective of this titling work is to redesign the wastewater treatment system of the José Laura tannery in the Province of Tungurahua. To this end, the waste water characterization of this company was carried out, which resulted in the discharge of the process effluent riparian conductivity values 27,8 mS/cm, BOD 13 700 mg/L, COD 22 200 mg/L, pH 12,6, SD 20 mL/L, SST 2500 mg/L, ST 4200 mg/L, sulphides 1536 mg/L and turbidity 7430 NTU. Regarding the discharge effluent from the tanning process, the conductivity value was obtained 54,2 mS/cm, hexavalent chromium 0,7 mg/L, trivalent chromium 122,98 mg/L, BOD 6640 mg/L, COD 14 760 mg/L, pH 5,1, SD 15 mL/L, SST 1000 mg/L, ST 2280 mg/L and turbidity 3820 NTU. In order to comply with the environmental legislation for the discharge of effluents to public sewage system, a physicochemical treatment is applied which for the riverbank process begins with the oxidation of sulfides, using manganese sulphate as a catalyst and a constant supply of air. In addition, for the tanning effluent it starts with the addition of lime to raise its pH up to 8,5 and with that, helps the precipitation of chromium, such as chromium (III) hydroxide. Finally, a coagulation-flocculation is applied to the two types of wastewater using aluminum polychloride (PAC) and anionic polyelectrolyte. All of this is determined by jug testing. With the application of this treatment conditions are given so that the residual water can enter a recirculation to the process of soaking and washing at the beginning of the tanning process of skins, since, it removes its main contaminants in an amount greater than 90% in almost all cases in particular to sulphides and total chromium considered hazardous waste.