Department of Civil and Environmental Engineering, South Dakota State University, Brookings, SD, 57007, USA.
Department of Civil and Environmental Engineering, South Dakota State University, Brookings, SD, 57007, USA.
J Environ Manage. 2021 Dec 15;300:113722. doi: 10.1016/j.jenvman.2021.113722. Epub 2021 Sep 17.
Nitrogen and phosphorus are two primary nutrients that can promote eutrophication in aquatic ecosystems. Recycled steel chips have been proposed to be used in conjunction with woodchips in dual-media treatment systems to remove nutrients from water, but the effects of different pairing configurations of woodchips and steel chips on nutrient removal have not been fully understood. The use of woodchips and steel chips for water treatment can result in leaching of organic carbon and iron. However, little is known about the impact of different media configurations on organics and iron leaching. In this study, laboratory column reactors using woodchips and steel chips (volumetric ratio of 11:1) were constructed based on three pairing configurations: woodchips/steel chips, steel chips/woodchips, and mixture of the two media. The column reactors were operated to evaluate nitrate and phosphate removal efficiencies and organic carbon and iron leaching from different media pairing arrangements. The results showed that the three media pairing configurations achieved similar overall nitrate and phosphate removal efficiencies but resulted in substantially different organic carbon and iron concentrations in reactor effluents. Steel chips, when placed downstream of woodchips reduced reactor organic carbon leaching, whereas woodchips, when placed downstream of steel chips reduced reactor iron leaching. The mixed media reactor was able to effectively control both organic carbon and iron leaching. The results of flow and temperature variation experiments showed that phosphate removal efficiencies by the steel chip filter were much less affected by flow and temperature changes than nitrate removal efficiencies by the woodchip bioreactor.
氮和磷是促进水生生态系统富营养化的两种主要营养物质。有人提议将再生钢屑与木屑结合使用，在双介质处理系统中去除水中的营养物质，但不同木屑和钢屑配对配置对营养物质去除的影响尚未完全了解。木屑和钢屑用于水处理会导致有机碳和铁的浸出。然而，对于不同介质配置对有机物和铁浸出的影响知之甚少。本研究基于三种配对配置（木屑/钢屑、钢屑/木屑和两种介质的混合物），构建了使用木屑和钢屑（体积比为 11:1）的实验室柱式反应器。对柱式反应器进行了操作，以评估不同介质配对布置对硝酸盐和磷酸盐去除效率以及有机碳和铁浸出的影响。结果表明，三种介质配对配置实现了相似的硝酸盐和磷酸盐总体去除效率，但在反应器流出物中的有机碳和铁浓度却有很大差异。钢屑放在木屑下游可减少反应器的有机碳浸出，而木屑放在钢屑下游则可减少反应器的铁浸出。混合介质反应器能够有效地控制有机碳和铁的浸出。流量和温度变化实验的结果表明，钢屑过滤器对磷酸盐的去除效率受流量和温度变化的影响远小于木屑生物反应器对硝酸盐的去除效率。
