Diseño de un sistema de tratamiento físico-químico de drenaje de minas.

Abstract

In this project, a mine drainage treatment process was designed and implemented using the physicochemical systems of sedimentation and coagulation-flocculation. An effective sedimentation column was constructed that removed a large part of the suspended particles from the mine drainage and then the flocculation coagulation system was implemented with poly aluminum chloride (PAC) and polyacrylamide (PAM), in order to remove the largest amount of contamination and obtain water suitable for discharge into a freshwater effluent as indicated in the TULSMA. The objective of the research was to propose an effective and economically viable system that would allow mining companies to carry out a correct treatment of the drainage produced. Through a jar test, several tests were carried out to determine the optimal dosages of PAC and PAM for the treatment; the experiments were analyzed with the Design Expert 11 program. A Box Behnken design (DBB) was used where the response variables were turbidity, color, turbidity and color removal percentages, and the chemical oxygen demand (COD) was also a parameter measured in the different experiments. The statistical analysis applied for turbidity removal in the flocculation coagulation process determined that the quadratic model has a predicted R2 of 0.7442 and an adjusted R2 of 0.9337, which indicates that both values are in agreement and that the model applied is correct. The results obtained from the experiments carried out in the coagulation and flocculation system allowed us to affirm that for the treatment of this mine drainage the optimum dose of PAC was 1.2 mg/L and of PAM 0.25 mg/L, working with a neutral pH. These doses allowed us to remove 90.14% of the turbidity, reduced the color to 7 PtCo units, reduced the concentration of copper present to 0.036 mg/L and also reduced the COD to 42.5 mg/L. All these parameters comply with the permissible limits for discharge into a freshwater body in Ecuador.