Nutrient losses from agricultural fields have long been a matter of concern worldwide due to the ecological disturbance this can cause to surface waters downstream. In this paper a new design concept, which pairs a surface-flow constructed wetland (SFW) with a woodchip bioreactor (WB), was tested in relation to its capacity to reduce both nitrogen (N) and phosphorus (P) loads from agricultural tile drainage water. A nutrient mass balance and a comparative analysis were carried out together with statistical regressions in order to evaluate the performance of four SFW+WBs under different catchment conditions. We found marked variations between the systems in regard to hydraulic loading rate (0.0 to 5.0 m/day) and hydraulic retention time (1 to 87 days). The paired system worked as nutrient sinks throughout the study period. Total N and total P removal efficiencies varied from 8% to 51% and from 0% to 80%, respectively. The results support the use of the new design concept for nutrient removal from tile-drained agricultural catchments in Denmark as part of national management plans, with the added advantage that smaller areas are needed for construction (0.1% to 0.2% of the catchment area) in comparison to standalone and currently used SCWs (~1%).

中文翻译：

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表流湿地与木片生物反应器配合处理农业排水

由于可能对下游地表水造成生态干扰，农田的养分损失长期以来一直是全世界关注的问题。在本文中，一种新的设计概念将表面流人工湿地 (SFW) 与木片生物反应器 (WB) 配对，测试了其减少农用瓷砖中氮 (N) 和磷 (P) 负荷的能力排水。营养物质平衡和比较分析与统计回归一起进行，以评估四种 SFW+WB 在不同流域条件下的性能。我们发现系统之间在水力加载速率（0.0 至 5.0 m/天）和水力停留时间（1 至 87 天）方面存在显着差异。在整个研究期间，配对系统充当营养库。总氮和总磷的去除效率分别从 8% 到 51% 和从 0% 到 80% 不等。结果支持将丹麦瓷砖排水农业集水区养分去除的新设计概念作为国家管理计划的一部分，并具有额外的优势，即建设所需的面积较小（集水区面积的 0.1% 至 0.2%）与独立的和当前使用的 SCW (~1%) 相比。