Chemical evolution of disposal brine of the Cerro Prieto geothermal field during its transport toward surrounding soils, Mexico

The exceeding brines of Cerro Prieto Geothermal Field (CPGF) are disposed into a lagoon and part of them infiltrate into the upper aquifer. This work describes the geochemical processes of how geothermal brine reaches the soils to the south and southwest of CPGF according to local flow lines from piezometric measurements. Soil and groundwater samples were collected and analyzed in the CPGF and the surrounding area. The model was divided into three stages: (a) Capillary rising-evaporation; (b) Mixture: geothermal brine-irrigation water and (c) Mixture-capillary rising-evaporation. The modeling was carried out taking into account the saturation stage of each solution. The mixture models and evaporation process were carried out considering a mass balance. The proposed model shows the pollution processes due to power generation through accumulation of evaporation pond soluble salts on agricultural lands in the CPGF surrounding area.