Sellner Bjorn M, Hua Guanghui, Ahiablame Laurent M, Trooien Todd P, Hay Christopher H, Kjaersgaard Jeppe
a Department of Civil and Environmental Engineering , South Dakota State University , Brookings , SD , USA.
b Department of Agricultural and Biosystems Engineering , South Dakota State University , Brookings , SD , USA.
Environ Technol. 2019 Feb;40(6):756-767. doi: 10.1080/09593330.2017.1407364. Epub 2017 Dec 4.
Agricultural subsurface drainage has been recognized as an important pathway for phosphorus transport from soils to surface waters. Reactive permeable filters are a promising technology to remove phosphate from subsurface drainage. Three natural minerals (limestone, zeolite, and calcite) and five industrial by-products (steel slag, iron filings, and three recycled steel by-products) were evaluated for phosphate removal from subsurface drainage using batch adsorption experiments. Phosphate adsorption onto these materials was characterized by Langmuir isotherm and second-order kinetic models. The adsorption capacities increased by factors of 1.2-2.5 when temperature was increased from 5°C to 30°C. Industrial by-products exhibited phosphate adsorption capacities that were one order of magnitude higher than natural minerals. Medium-sized steel chips exhibited high phosphate adsorption capacities (1.64-3.38 mg/g) across different temperatures, pH values, organic matter concentrations, and real drainage water matrixes. The strong chemical bonds between phosphate and steel by-products prevented the release of adsorbed phosphate back to the solution. The steel by-product filter can be paired with a woodchip bioreactor for nitrate and phosphate removal. It is suggested that the phosphate filter be connected to a woodchip bioreactor after the startup phase to minimize the impact of dissolved organic matter on phosphate adsorption. The results of this study suggest that the low-cost steel by-products examined could be used as effective adsorption media for phosphate removal from subsurface drainage.
农业地下排水已被公认为是磷从土壤输送到地表水的一条重要途径。反应性渗透过滤器是一种从地下排水中去除磷酸盐的很有前景的技术。使用批量吸附实验评估了三种天然矿物（石灰石、沸石和方解石）和五种工业副产品（钢渣、铁屑和三种再生钢副产品）对地下排水中磷酸盐的去除效果。这些材料对磷酸盐的吸附用朗缪尔等温线和二级动力学模型进行了表征。当温度从5°C升高到30°C时，吸附容量增加了1.2至2.5倍。工业副产品表现出的磷酸盐吸附容量比天然矿物高一个数量级。中等尺寸的钢屑在不同温度、pH值、有机物浓度和实际排水水质条件下均表现出较高的磷酸盐吸附容量（1.64 - 3.38 mg/g）。磷酸盐与钢副产品之间的强化学键阻止了吸附的磷酸盐重新释放回溶液中。钢副产品过滤器可与木屑生物反应器配合使用以去除硝酸盐和磷酸盐。建议在启动阶段之后将磷酸盐过滤器连接到木屑生物反应器，以尽量减少溶解有机物对磷酸盐吸附的影响。本研究结果表明，所研究的低成本钢副产品可作为从地下排水中去除磷酸盐的有效吸附介质。
