Bioretention systems have been proved to be a natural approach for effectively reducing stormwater runoff pollution loads. The filler is essential for the function of the bioretention systems; there are few studies on the use of biochar for bioretention. In this study, corn straw was used as raw material to prepare biochar bioretention-improved filler, and the optimal preparation scheme and filler proportioning method were determined. Three layered bioretention columns, i.e., BSM (bioretention soil media), BSM + 5%WTR (water treatment residues, w/w) and BSM + 5%CSC (corn straw biochar, w/w), were built to analyze its regulating effect on rainwater runoff. The DRAINMOD model was established based on the test results to analyze the regulating effect in different situations. The key parameters of the bioretention systems were optimized using response surface methodology (RSM). The results show that: BSM + 5%CSC was more stable than BSM + 5%WTR for water volume control effect and was better than BSM. The load reduction rates of BSM + 5%CSC was better than that of BSM and BSM + 5%WTR. When only considering the optimal nitrogen reduction effect, it was necessary to deepen the depth of the submerged area to improve the nitrogen control effect. When considering the optimal control effects of water volume and nitrogen, the thickness of the filler layer was the key factor affecting the water reduction rate. Overall, this study demonstrated that corn straw biochar can effectively improve the regulation effect of bioretention systems, and the optimization of parameters can provide references for the design of bioretention systems.

生物滞留系统已被证明是有效减少雨水径流污染负荷的自然方法。填料对于生物滞留系统的功能至关重要；关于使用 biochar 进行生物保留的研究很少。本研究以玉米秸秆为原料制备生物炭生物滞留性改良填料，确定了最佳制备方案和填料配比方法。建立三层生物滞留柱，即 BSM（生物滞留土壤介质）、BSM+5%WTR（水处理残留物，w/w）和 BSM+5%CSC（玉米秸秆生物炭，w/w），分析其调节作用。对雨水径流的影响。根据试验结果建立DRAINMOD模型，分析不同情况下的调节效果。使用响应面方法 (RSM) 优化了生物滞留系统的关键参数。结果表明：BSM+5%CSC对水量控制效果比BSM+5%WTR更稳定，优于BSM。BSM+5%CSC的减载率优于BSM和BSM+5%WTR。当只考虑最佳减氮效果时，需要加深淹没区的深度，以提高氮的控制效果。在考虑水量和氮气的最优控制效果时，填料层的厚度是影响减水率的关键因素。总体而言，本研究表明玉米秸秆生物炭可以有效提高生物滞留系统的调节效果，