去除硬度的过程，尤其是 用于去除镁（Mg）和 二氧化硅（Si）非常依赖于pH值。A. 这项研究是为了确定 曝气在多大程度上可以取代化学药剂 作为钙（Ca）的一种添加方式 移动进行了台架试验 地下水中含有过饱和的 二氧化碳（CO2）和含有钙， 镁和硅。 石灰和纯碱的最佳用量 （OLSA）导致79%的Ca和 镁硬度和23%的硅去除率。附加 OLSA过程中添加铁盐可改善浊度 去除，对钙或硅的影响最小 去除，并减少镁的去除，除非 pH值被重新调整。铝酸钠添加 在OLSA期间，浊度有所改善 去除和增加沉淀污泥粘度 但不影响钙、镁或硅的去除。这个 作者发现，从水中去除钙 取决于“种子”粒子的存在 方解石矿物沉淀在其上；这个 添加一个核种子增加了溶解 钙去除率从60%降至80%以上。添加 聚合物会影响污泥的密度 这些都是生产出来的。 在这些实验的基础上，进行了曝气试验 剥离似乎最合适 对于二氧化碳和二氧化碳过饱和的水 主要含有碳酸钙 硬度。对于使用这些源的实用程序 沃特斯，这篇文章提供了更好的理解 方解石化学效应的研究 在曝气和软化过程中 应该帮助他们提高钙去除率，同时 尽量减少化学添加剂和污泥 生产包括20个参考文献、表格和图表。

Hardness removal processes, especially for removing magnesium (Mg) and silica (Si), are very pH-dependent. A study was undertaken to determine the extent to which aeration could replace chemical addition as a means of calcium (Ca) removal. Bench-scale tests were conducted with a groundwater supersaturated with carbon dioxide (CO2) and containing Ca, Mg, and Si. Optimal dosing of lime and soda ash (OLSA) resulted in 79% removal of Ca and Mg hardness and 23% Si removal. Addition of iron salts during OLSA improved turbidity removal, had minimal effect on Ca or Si removal, and decreased Mg removal unless pH was readjusted. Sodium aluminate addition during OLSA improved turbidity removal and increased settled sludge viscosity but did not affect Ca, Mg, or Si removal. The authors found that removing Ca from water depends on the presence of "seed" particles onto which calcite minerals precipitate; the addition of a nuclei seed increased dissolved Ca removal from 60 to > 80%. Addition of polymers affects the density of the sludges that are produced. On the basis of these experiments, aeration stripping would appear most appropriate for waters supersaturated with CO2 and containing predominating calcium carbonate hardness. For utilities using these source waters, the article offers a better understanding of the effects of calcite chemistry on aeration and softening processes that should help them improve Ca removal while minimizing chemical addition and sludge production. Includes 20 references, tables, figures.