To overcome the global water shortage, the treated wastewater is increasingly utilized in agricultural irrigation, and thus reducing freshwater consumption and increasing the water sustainability. Drip irrigation technology is the most appropriate irrigation method to utilize these water sources. However, its operating performance is negatively affected by calcium carbonate (CaCO) scaling, which is one of the most dominant precipitations and also closely related to dissolved ions and the hydraulic characteristics inside irrigation systems. Thus, the effects of eight common dissolved ions (K, Mg, Mn, Zn, Fe, NO, SO, and PO) in these water sources and four hydraulic shear stresses (0, 0.2, 0.4, and 0.6 Pa) on CaCO scaling formation were assessed in this study. Results showed that CaCO scaling was primarily formed of calcite and aragonite. Fe would significantly accelerate the CaCO scaling accumulation, as it reduced the unit cell volume and chemical bonds of calcite, enhancing calcite adhesion and stability. On the other hand, Mg, Mn, NO, SO, and PO significantly inhibited CaCO scaling. Among them, Mg, Mn, and PO followed the typical water chemical precipitation rule, while NO increased water molecule diffusion rate and thus decreased the possibility that Ca and CO to precipitate. SO grabbed the binding point belonging to CO and was adsorbed on the calcite crystal, which inhibited crystal growth. However, those treatments under K and Zn did not reach a significant level due to their solubleness. During the precipitation of CaCO, there were significant ( < 0.01) interactions between dissolved ions and hydraulic shear stresses. When hydraulic shear stresses varied, the effects of Fe and SO on the CaCO scaling were relatively weakened, while that of Mg was relatively strengthened. In return, dissolved ions affected the effect of hydraulic shear stresses on CaCO scaling. Overall, the results obtained could provide theoretical reference for high-efficiency utilization of treated wastewater for agricultural irrigation through the management of CaCO scaling.

中文翻译：

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通过滴灌系统回用处理后的废水的全面和分子水平评估：溶解离子和水力剪切应力对碳酸钙结垢的相互作用

为了克服全球水资源短缺的问题，处理后的废水越来越多地用于农业灌溉，从而减少淡水消耗并提高水的可持续性。滴灌技术是利用这些水源最合适的灌溉方法。然而，其运行性能受到碳酸钙 (CaCO) 结垢的负面影响，碳酸钙 (CaCO) 结垢是最主要的降水之一，也与溶解离子和灌溉系统内的水力特性密切相关。因此，这些水源中八种常见溶解离子（K、Mg、Mn、Zn、Fe、NO、SO 和 PO）和四种水力剪切应力（0、0.2、0.4 和 0.6 Pa）对 CaCO 结垢的影响本研究中评估了形成。结果表明，CaCO结垢主要由方解石和文石组成。 Fe会显着加速CaCO结垢的积累，因为它减少了方解石的晶胞体积和化学键，增强了方解石的粘附性和稳定性。另一方面，Mg、Mn、NO、SO 和 PO 显着抑制 CaCO 结垢。其中，Mg、Mn和PO遵循典型的水化学沉淀规律，而NO则增加了水分子的扩散速率，从而降低了Ca和CO沉淀的可能性。 SO抢占CO的结合点，吸附在方解石晶体上，抑制晶体生长。然而，由于其溶解性，钾和锌的处理并未达到显着水平。在 CaCO3 沉淀过程中，溶解离子和水力剪切应力之间存在显着的 (< 0.01) 相互作用。当水剪应力变化时，Fe和SO对CaCO结垢的影响相对减弱，而Mg的影响相对增强。反过来，溶解的离子会影响水力剪切应力对 CaCO 结垢的影响。总体而言，所获得的结果可以为通过CaCO结垢管理处理后的废水高效利用于农业灌溉提供理论参考。