State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China.
J Contam Hydrol. 2013 Nov;154:1-9. doi: 10.1016/j.jconhyd.2013.08.002. Epub 2013 Aug 28.
An effective and low-cost in-situ geological filtration system was developed to treat arsenic-contaminated groundwater in remote rural areas. Hangjinhouqi in western Hetao Plain of Inner Mongolia, China, where groundwater contains a high arsenic concentration, was selected as the study area. Fe-mineral and limestone widely distributed in the study area were used as filter materials. Batch and column experiments as well as field tests were performed to determine optimal filtration parameters and to evaluate the effectiveness of the technology for arsenic removal under different hydrogeochemical conditions. A mixture containing natural Fe-mineral (hematite and goethite) and limestone at a mass ratio of 2:1 was found to be the most effective for arsenic removal. The results indicated that Fe-mineral in the mixture played a major role for arsenic removal. Meanwhile, limestone buffered groundwater pH to be conducive for the optimal arsenic removal. As(III) adsorption and oxidation by iron mineral, and the formation of Ca-As(V) precipitation with Ca contributed from limestone dissolution were likely mechanisms leading to the As removal. Field demonstrations revealed that a geological filter bed filled with the proposed mineral mixture reduced groundwater arsenic concentration from 400 μg/L to below 10 μg/L. The filtration system was continuously operated for a total volume of 365,000L, which is sufficient for drinking water supplying a rural household of 5 persons for 5 years at a rate of 40 L per person per day.
开发了一种高效且低成本的原位地质过滤系统，用于处理偏远农村地区受砷污染的地下水。中国内蒙古河套平原西部的杭锦后旗，其地下水中砷浓度较高，被选为研究区。研究区广泛分布的铁矿物和石灰石被用作过滤材料。通过批量和柱实验以及现场测试，确定了最佳过滤参数，并评估了该技术在不同水文地球化学条件下去除砷的效果。研究发现，由天然铁矿物（赤铁矿和针铁矿）和石灰石按质量比 2:1 混合而成的混合物对砷的去除效果最佳。结果表明，混合物中的铁矿物在砷去除过程中起主要作用。同时，石灰石将地下水的 pH 值缓冲至有利于最佳砷去除的水平。铁矿物对 As(III)的吸附和氧化，以及来自石灰石溶解的 Ca 与 As(V)形成 Ca-As(V)沉淀，可能是导致砷去除的机制。现场示范表明，填充有建议的矿物混合物的地质过滤床可将地下水砷浓度从 400μg/L 降低至 10μg/L 以下。该过滤系统连续运行总水量为 365,000L，足以满足一个 5 口之家每天每人 40L 的饮用水供应，持续 5 年。
