Brunsting Joseph H, McBean Edward A
a School of Engineering, University of Guelph , Guelph , Ontario , Canada.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2014;49(6):671-8. doi: 10.1080/10934529.2014.865449.
Contamination of groundwater by arsenic is a problem in many areas of the world, particularly in West Bengal (India) and Bangladesh, where reducing conditions in groundwater are the cause. In situ treatment is a novel approach wherein, by introduction of dissolved oxygen (DO), advantages over other treatment methods can be achieved through simplicity, not using chemicals, and not requiring disposal of arsenic-rich wastes. A lab-scale test of in situ treatment by air sparging, using a solution with approximately 5.3 mg L(-1) ferrous iron and 200 μg L(-1) arsenate, showed removal of arsenate in the range of 59%. A significant obstacle exists, however, due to the interference of phosphate since phosphate competes for adsorption sites on oxidized iron precipitates. A lab-scale test including 0.5 mg L(-1) phosphate showed negligible removal of arsenate. In situ treatment by air sparging demonstrates considerable promise for removal of arsenic from groundwater where iron is present in considerable quantities and phosphates are low.
砷对地下水的污染是世界上许多地区面临的一个问题，尤其是在西孟加拉邦（印度）和孟加拉国，那里地下水的还原条件是导致污染的原因。原位处理是一种新颖的方法，通过引入溶解氧（DO），可以通过简单性、不使用化学物质以及无需处置富含砷的废物等优点，优于其他处理方法。一项实验室规模的空气曝气原位处理试验，使用含有约5.3 mg L⁻¹亚铁离子和200 μg L⁻¹砷酸盐的溶液，结果表明砷酸盐的去除率在59%左右。然而，由于磷酸盐的干扰存在一个重大障碍，因为磷酸盐会竞争氧化铁沉淀物上的吸附位点。一项包含0.5 mg L⁻¹磷酸盐的实验室规模试验表明，砷酸盐的去除率可忽略不计。在铁含量相当高且磷酸盐含量低的地下水中，通过空气曝气进行原位处理在去除砷方面显示出相当大的前景。
