不同前处理下咸水冰融水水质与水量特征

Quality and quantity characteristics of saline ice meltwater under different pretreatments

  • 摘要: 咸水结冰灌溉对重度盐碱地改良, 缓解淡水资源短缺具有重要现实意义。咸水冰融化过程中水盐分离的实质是盐分的再分配过程。为厘清前处理对咸水冰融化过程中水质及水量的影响, 本研究设计了曝气冰(A)、堆积冰(S)、破碎冰(C)和常规冰(R) 4种前处理, 及4个初始矿化度(0 g∙L−1、5 g∙L−1、10 g∙L−1、15 g∙L−1), 对比分析融水过程中水量和水质的动态变化。结果表明, 曝气、堆积和破碎处理相对常规冰都能显著减少融化时间, 各处理融化时间为破碎冰<堆积冰<曝气冰<常规冰; 单位时间融出水量均呈先快速升高, 后缓慢降低的趋势, 峰值水量为常规冰<曝气冰<堆积冰<破碎冰。随着融化过程的进行, 融水矿化度快速下降, 之后逐渐平缓; 其中, 破碎冰初始和结束时融水矿化度和钠吸附比(SAR)均显著低于常规冰; 且初始矿化度为5 g∙L−1时破碎冰的淡水(<1 g∙L−1)融出量高达33.26%, 显著高于同矿化度的其他前处理冰体。可见, 前处理措施可以显著改变咸水冰融化过程中的水盐再分配过程, 这为地下咸水资源利用时通过咸水冰前处理提高盐分淋洗能力提供了理论依据。

     

    Abstract: 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·L1 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∙L1) yield was 33.26% at the initial TDS of 5 g∙L1 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.

     

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