Alternatives in the reduction of groundwater hardness in Saltapuquio Michiquillay sector, district of La Encañada - Cajamarca

Abstract

The Michiquillay Sector, an area influenced by an early-stage exploration mining project, necessitates meticulous consideration of water quality and quantity, adhering to the Maximum Permissible Limits (MPL) and Environmental Quality Standards (EQS) established by the current regulations, such as the Ley General del Ambiente 28611, the Ley de los Recursos Hídricos 29335, and the Autoridad Nacional del Agua. This study addressed the initial state of water in Saltapuquio, Michiquillay, Cajamarca, evaluating its physicochemical (hardness, conductivity, biochemical oxygen demand, chemical oxygen demand, and nitrate) and biological (Escherichia coli and total coliform bacteria) characteristics for a chemical treatment aimed at reducing hardness. The results, obtained using the EDTA method, indicated a hardness of 665.80 mg/L, surpassing the limits allowed by the Regulation of Water Quality for Human Consumption (D.S. N° 031-2010-SA). To counteract this situation, a chemical treatment with lime and sodium tripolyphosphate was implemented, concluding that the latter compound was optimal for hardness reduction, in compliance with Supreme Decree N° 031-2010-SA, which sets a maximum permissible limit of 500 mg/L.