The changes in the concentrations of Ca, dissolved silica, and alkalinity of the recovery waters of four short‐term aquifer thermal energy storage test cycles with respect to the injection waters and the correlation of these concentrations with recovery water temperatures indicate that quartz and calcite dissolved during hot water storage. This hypothesis was supported by chemical equilibrium modeling and mass balance calculations. Magnesium concentrations were lower in recovery waters than in injection waters. Chemical equilibrium modeling indicated that a Mg silicate (talc) could have precipitated. Potassium concentrations correlated well with temperatures, probably because of ion exchange involving potassium feldspars in the aquifer.
ASJC Scopus subject areas
- Water Science and Technology