Quality and quantity characteristics of saline ice meltwater under different pretreatments

Saline ice irrigation has a positive effect on heavy saline land reclamation and is of great practical importance for alleviating freshwater shortages. Water-salt separation is a salt redistribution process during saline ice melting. We aimed to clarify the influence of pretreatment on the quantity and quality of melted water and the melting duration of saline ice. To achieve these parameters, four ice pretreatments, including aerated ice, stacked ice, crushed ice, and regular ice; and four initial total dissolved solids (TDS) of saline ice of 0, 5, 10, and 15 g·L⁻¹ were used to compare and analyze the dynamics of water quantity and quality during the saline ice melting process. The results showed that aeration, stacking, and crushing treatments significantly reduced the melting duration compared with that of regular ice. The melting duration of each treatment was crushed ice < stacked ice < aerated ice < regular ice. The meltwater volume per unit time showed a trend of rapid increase followed by a gradual decrease, with the peak water volume in the order of regular ice < aerated ice < stacked ice < crushed ice. As the melting process continued, the TDS of the meltwater decreased rapidly and finally stabilized. Among all the pretreatments, the TDS and sodium adsorption ratio (SAR) of meltwater from crushed ice were significantly lower than those from regular ice. The highest freshwater (<1 g∙L⁻¹) yield was 33.26% at the initial TDS of 5 g∙L⁻¹ for crushed ice. Pretreatment measures can significantly change the water-salt reallocation process of saline ice melting, which provides a theoretical basis for utilization of saline groundwater resources.