Media amendment has been more and more frequently tested in stormwater bioretention systems for enhanced runoff pollutant treatment. However, few studies systematically evaluated the amended system over a long time span, which hindered the further optimization of the proposed amended media. In this study, biochar-pyrite system (PB), conventional sand system (SB), and biochar-woodchip system (WB) were established and operated for 26 months. Media amendment greatly enhanced the dissolved nutrient removal, the highest total dissolved nitrogen removal in PB and WB were 65.6±3.6% and 68.2±2.5%, respectively. Compared with PB, WB could maintain excellent nitrogen removal under long-term operation. In contrast, PB demonstrated stable and more effective total dissolved phosphorus removal during all stages (73.1±3.1%-80.3±4.1%). A high content of phosphorus and organic matter was leached in WB especially at initial operation, while the initial pollutant leaching in PB and SB is much lower, about one-third of WB. Microbial and metabolic function analysis indicated that the microbial community in the bioretention system is complicated and stable. Media amendment enhanced microbial diversity and the relative abundance of functional genera related to nitrogen (Nitrospira, Thauera, Denitratisoma, etc.), sulfur (Thiobacillus, Geobacter, Desulfovibrio, etc.), and carbon cycles (cellulomonas, saccharimonadales, and SBR1031, etc.), which well explained the enhanced pollutant removal and by-product leaching in different systems. Overall, the current study indicates that although media amendment is conducive to enhanced dissolved nutrient removal in bioretention systems, it can hardly maintain both stability and efficiency from initial set-up to long-term operation. In practical application, catchment characteristics, prioritized pollutants, meteorological factors, etc. should all be considered before choosing suitable amended media and its design factors, thereby maximising the stability and efficiency of the bioretention system.

在雨水生物滞留系统中越来越频繁地测试介质修正，以增强径流污染物的处理。然而，很少有研究在很长一段时间内对修正后的系统进行系统评估，这阻碍了对拟议修正媒体的进一步优化。本研究建立了生物炭-黄铁矿系统（PB）、常规砂系统（SB）和生物炭-木片系统（WB），并运行了26个月。培养基改良大大提高了溶解养分的去除率，PB和WB中最高的总溶解氮去除率分别为65.6±3.6%和68.2±2.5%。与PB相比，WB在长期运行下仍能保持良好的脱氮效果。相比之下，PB 在所有阶段都表现出稳定且更有效的总溶解磷去除（73.1±3.1%-80.3±4.1%）。尤其是在运行初期，WB 中磷和有机物的浸出量较高，而 PB 和 SB 中的初始污染物浸出量要低得多，约为 WB 的三分之一。微生物和代谢功能分析表明，生物滞留系统中的微生物群落复杂而稳定。培养基改良增强了微生物多样性和与氮相关的功能属的相对丰度（Nitrospira、Thauera、Denitratisoma等）、硫（硫杆菌、Geobacter、Desulfovibrio等）和碳循环（纤维单胞菌、糖单胞菌和SBR1031等），这很好地解释了不同系统中增强的污染物去除和副产物浸出。总体而言，目前的研究表明，尽管培养基修正有利于提高生物滞留系统中溶解性营养物质的去除率，但从初始设置到长期运行，它很难同时保持稳定性和效率。在实际应用中，在选择合适的修正介质及其设计因素之前，应综合考虑流域特征、优先污染物、气象因素等，从而最大限度地提高生物滞留系统的稳定性和效率。