从6月开始进行的全国地下水供应调查 1998年至1999年6月发现砷（As）浓度 超过0.010 mg/L在美国很普遍。在里面 2001年1月，美国环境保护署发布了一份 将As最大污染物水平从0.05降至 0.010 mg/L。为了达到这一新标准，许多公用事业公司可能需要 升级现有设施或研究新的治疗方案。他们 还需要准确评估现有治疗的能力 持续降低至低水平的技术。 作者进行了为期一年的研究，以评估 五个从原料中去除砷的全面设施的性能 水两个混凝过滤厂的评价一致 达到了低水平的As。然而，当一个设施 将其凝固剂从明矾改为聚合氯化铝，平均 去除效率从84%下降到43%，这一下降 这可能是由于两种除铁方法的pH值不同造成的 设施，其中一个持续降低浓度；添加 然而，凝固剂应该有助于改善另一种植物的As 移动石灰软化厂无法持续运行 降低As至低水平，但通过 增加石灰用量可以提高去除效率。 传统的处理技术能够去除 从供水到液位< 10 ug/L，以确保最佳 然而，去除过程可能需要修改。 优化搬迁的效用必须考虑其影响 这些修改可能会影响系统性能和成本， 以及可能由以下原因引发的其他性能问题: 水化学的变化。包括33个参考文献、表格和图表。

A survey of national groundwater supplies conducted from June 1998 to June 1999 found that arsenic (As) concentrations exceeding 0.010 mg/L are widespread in the United States. In January 2001, the US Environmental Protection Agency published a final rule to lower the As maximum contaminant level from 0.05 to 0.010 mg/L. To meet this new standard, many utilities may need to upgrade current facilities or investigate new treatment options. They also need an accurate appraisal of the ability of existing treatment technologies to consistently reduce As to low levels. The authors conducted a year-long study to evaluate the performance of five full-scale facilities for removing As from raw water. The two coagulation-filtration plants evaluated consistently achieved low levels of As. However, when one facility changed its coagulant from alum to polyaluminum chloride, average removal efficiency plunged from 84 to 43%, a reduction that might be attributable to difference in pH. Of the two iron-removal facilities, one consistently reduced As concentrations; addition of a coagulant, however, should help improve the other plant's As removal. The lime-softening plant was unable to consistently reduce As to low levels, but raising the operating pH through increased lime dosage may improve removal efficiencies. Conventional treatment technologies are capable of removing As from water supplies to levels < 10 ug/L. To ensure optimal As removal, however, treatment processes may need modifications. Utilities intent on optimizing As removal must consider the effect these modifications may have on system performance and costs, as well as other performance issues that may be triggered by changes in water chemistry. Includes 33 references, tables, figures.