Many times the quality of a treated effluent from a mining operation does not comply with the required legislation as in the case of Peru, where Maximum Permissible Limits for mining operations are not met due to the content of metals such as manganese, which usually requires specific conditions for removal. Therefore, some re-evaluation tests were made to the treatment system, mainly in the neutralization stage of the effluent, in order to identify the problem and propose possible solutions.
The study considers a first stage or experimental phase in which a set of laboratory tests were carried out. The first differentiating criterion is the type of neutralization applied (direct or sequential neutralization); the second criterion is to minimize the number of reagents in the process while maintaining the effectiveness of the implemented treatment system. In addition to the tests, there are continuous measurements carried out before, during and after the experimental tests, of parameters such as pH, electrical conductivity and the oxide reduction potential, which allowed for the identification of cut-off times in the proposed treatment.
As a result of the study, the manganese surplus was removed from the treated effluent; we were able to identify the sequence that allowed compliance with Peruvian Maximum Permissible Limits; finally, we agreed on the need to implement a modification to the existing treatment system, in compliance with the legislation, and with the lowest operational possible cost.
