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素。已提出将回收钢片与双介质处理系统中的木片结合使用以去除水中的营养物，但木片和钢片的不同配对配置对营养物去除的影响尚未完全了解。使用木片和钢片进行水处理会导致有机碳和铁的浸出。然而，关于不同介质配置对有机物和铁浸出的影响知之甚少。在本研究中，使用木片和钢片（体积比为 11:1）的实验室柱式反应器基于三种配对配置构建：木片/钢片、钢片/木片和两种介质的混合物。操作塔式反应器以评估硝酸盐和磷酸盐的去除效率以及从不同介质配对布置中浸出的有机碳和铁。结果表明，三种介质配对配置实现了相似的整体硝酸盐和磷酸盐去除效率，但导致反应器流出物中的有机碳和铁浓度显着不同。钢片，当放置在木片的下游时，减少了反应器的有机碳浸出，而木片，当放置在钢片的下游时，减少了反应器的铁浸出。混合介质反应器能够有效控制有机碳和铁的浸出。