Department of Civil Engineering, Memorial University of Newfoundland, 40 Arctic Avenue, St. John's, NL, A1B 3X7, Canada.
Infrastructure Ontario, Suite 2000, 1 Dundas St. West, Toronto, ON, M5G 1Z3, Canada.
Environ Geochem Health. 2020 Nov;42(11):4051-4064. doi: 10.1007/s10653-020-00671-7. Epub 2020 Jul 21.
Natural groundwater from the towns of Wabana and Freshwater and treated well water from the town of Wabana in Newfoundland and Labrador, Canada were tested separately and together in sand columns to study the removal of arsenic. The most ideal conditions for arsenic removal appeared to include an arsenic concentration of approximately 35 µg/L and lower, an Fe:As mass ratio in the order of 65 and lower, and aeration of the sand media. Active aeration by pumping air though the filter, passive aeration by scraping off top layers of sand and virtual aeration by diluting the strength of the water being treated, were employed and compared. For tests where groundwater from the towns of Wabana and Freshwater was combined, arsenic removal was optimized and other elements, in addition to iron, were also correlated with effluent arsenic. Further, for these same tests there was a gradual increase in effluent pH that could have been due to oxygen depletion or gradually more reducing conditions in the sand column. Where Ni, Mn and Zn were correlated with effluent arsenic it was concluded that the increase in pH increased heavy metal removal and arsenic release. In the test where the treated Wabana water made up a greater proportion of the mix than the Wabana groundwater, lithium was also correlated with arsenic.
来自加拿大纽芬兰省瓦巴纳镇和淡水镇的天然地下水以及瓦巴纳镇处理过的井水，分别和一起在沙柱中进行了测试，以研究砷的去除情况。去除砷的最理想条件似乎包括砷浓度约为 35μg/L 及更低，Fe:As 质量比在 65 及更低，以及沙质介质的曝气。采用了通过过滤器泵入空气的主动曝气、刮去沙层顶层的被动曝气和通过稀释处理水的强度的虚拟曝气，并进行了比较。对于将瓦巴纳镇和淡水镇的地下水混合的测试，砷的去除得到了优化，除铁之外的其他元素也与出水砷相关。此外，对于这些相同的测试，出水中的 pH 值逐渐升高，这可能是由于沙柱中氧气耗尽或逐渐形成更还原的条件所致。在与出水中砷相关的 Ni、Mn 和 Zn 的测试中，结论是 pH 值的升高增加了重金属的去除和砷的释放。在瓦巴纳处理水比瓦巴纳地下水占更大比例的测试中，锂也与砷相关。
