State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
J Hazard Mater. 2012 Nov 15;239-240:308-15. doi: 10.1016/j.jhazmat.2012.08.079. Epub 2012 Sep 7.
Field studies were conducted to evaluate the feasibility of an in situ formed Fe-Mn binary oxide (in situ FMBO) for improving arsenic (As) removal in the aeration-direct filtration process. The transformation and transportation of As, Fe, and Mn in the filter bed were also investigated. The in situ FMBO increased the As removal efficiency by 20-50% to keep the residual As below 10 μg/L. The optimum FMBO dosage was determined to be 0.55 mg/L with the Fe/Mn ratio as 10:1. The removal of Fe, Mn, turbidity, and particles was also improved to a large extent. The in situ FMBO favored the transformation of soluble As, Fe, and Mn into the solid phases, benefiting the removal of these pollutants by the subsequent filtration. Moreover, the deposited precipitates onto the filter media were characterized, as indicated by the analyses of SEM/EDS and particle size distribution. The long-term experiments exhibited decreased head loss growth and prolonged run length, suggesting an enhanced pollutant catching capacity of the filter media. The full-scale field study with a flow of 10,000 m3/d confirmed positive effects of in situ FMBO on As removal, with the average effluent As concentration reduced from 20 μg/L to 6 μg/L (reagent cost=0.006 ¥/m3).
现场研究评估了在曝气直接过滤工艺中就地形成 Fe-Mn 二元氧化物（原位 FMBO）以提高砷（As）去除率的可行性。还研究了滤床中 As、Fe 和 Mn 的转化和迁移。原位 FMBO 将 As 去除效率提高了 20-50%，使残留 As 低于 10μg/L。确定最佳 FMBO 剂量为 0.55mg/L，Fe/Mn 比为 10:1。Fe、Mn、浊度和颗粒的去除也得到了很大程度的改善。原位 FMBO 有利于可溶性 As、Fe 和 Mn 向固相的转化，有利于随后过滤去除这些污染物。此外，还对沉积在过滤介质上的沉淀物进行了表征，SEM/EDS 分析和颗粒尺寸分布表明了这一点。长期实验表明，水头损失增长减少，运行时间延长，表明过滤介质的污染物捕集能力增强。10000m3/d 流量的现场全规模研究证实了原位 FMBO 对 As 去除的积极影响，出水 As 浓度平均值从 20μg/L 降低到 6μg/L（试剂成本=0.006 元/m3）。
