In this study, six permeable pavement systems (PPS) with different subbase configurations were tested to evaluate their nitrogen attenuation capabilities from urban stormwater runoff. The PPS subbases were configured based on the following rationale for achieving enhanced physical, chemical and biological treatment of nitrogen compounds commonly found in urban stormwater: (i) a layer of natural zeolite to enhance nitrogen removal by ion exchange and adsorption; (ii) a layer of bark chips as a carbon donor to enhance biodegradation; (iii) a saturated zone to maintain required moisture content and reduced oxygen level for enhanced denitrification and (iv) thin sand layer(s) to limit oxygen transport for creating an anoxic zone within the PPS. A laboratory water sampling and testing program was undertaken from these PPS over a six-month period using synthetic stormwater with different pollutant concentrations while simulating varying rainfall intensities to represent typical design rainfall events considered in urban stormwater management. Our results demonstrate an improved denitrification in the PPS when a saturated zone is maintained and an organic carbon source is added in the PPS subbase. Compared with the traditional PPS, the new PPS is found to attenuate twice the amount of the total inorganic nitrogen in stormwater. Also, the attenuation of nitrogen compounds by the standard PPS is found to be reduced with rainfall duration (e.g., 54% attenuation during the first hour and only 3.5% during the 4th hour of the rainfall). The new PPS is found to attenuate 68% of total inorganic nitrogen even in the 4th hour of the rainfall event. The new PPS has the potential to become an effective stormwater quality improvement device that can contribute towards cleaner urban waterways.

中文翻译：

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通过对标准透水路面结构的设计修改来增强反硝化


在本研究中，测试了六种具有不同底基层配置的渗透性路面系统（PPS），以评估其从城市雨水径流中的氮衰减能力。 PPS 底基的配置基于以下基本原理，以实现对城市雨水中常见氮化合物的强化物理、化学和生物处理：(i) 天然沸石层，通过离子交换和吸附增强氮去除； (ii) 一层树皮碎片作为碳供体以增强生物降解； (iii) 饱和区，以维持所需的水分含量和降低氧气水平，以增强反硝化作用；(iv) 薄砂层，以限制氧气传输，从而在 PPS 内创建缺氧区。这些 PPS 进行了为期六个月的实验室水采样和测试计划，使用具有不同污染物浓度的合成雨水，同时模拟不同的降雨强度，以代表城市雨水管理中考虑的典型设计降雨事件。我们的结果表明，当维持饱和区并在 PPS 底基层中添加有机碳源时，PPS 中的反硝化作用会得到改善。与传统的PPS相比，新的PPS被发现可以减少雨水中总无机氮含量的两倍。此外，还发现标准 PPS 对氮化合物的衰减随着降雨持续时间而减少（例如，在降雨的第一小时内衰减 54%，在降雨的第四小时内仅衰减 3.5%）。研究发现，即使在降雨事件的第 4 小时，新的 PPS 也能减少 68% 的总无机氮。 新的 PPS 有潜力成为一种有效的雨水质量改善装置，有助于清洁城市水道。