Integrated planning of urban blue–green infrastructures is crucial to strengthen urban environmental quality and mitigate negative climate change-associated effects. It implies, however, increased water demand for irrigation, wherefore greywater (wastewater excluding wastewater from toilets and urinals) can be used, yet it requires handling for safe reuse. One treatment option is the use of constructed wetlands (CW), which have thus far not been broadly applied in inner-city districts due to large area requirements. This work investigates a novel bipartite container-based vertical-flow constructed wetland (VFCW) for the treatment of light greywater (from showers and hand wash basins) and its use as irrigation water for urban facade greenery. The VFCW consists of two compartments with 2.5 m² filter area each, filled with 75 cm zeolite-containing lava sand (0–4 mm) and 75 cm Rhine sand (0–2 mm), respectively. In short, screening has proven to be well suitable for coarse solids removal, so there is no further need to settle light greywater, which reduces overall treatment area and benefits urban application. Treated greywater complied with irrigation standards at all times, yet mixing with rainwater can help reduce salt contents, if applicable. The modular/elevated lava sand VFCW exhibited extensive nitrification, even at extremely low water temperatures, as well as mean effluent concentrations of 6.3 mg/L COD and <0.05 mg/L P_tot, which makes it a very promising treatment option for greywater. All in all, the modular/elevated design promotes urban application of VFCW as a multifunctional blue–green system that can help increase urban resilience.

中文翻译：

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用于浅灰水处理的高架垂直流人工湿地

城市蓝绿基础设施的综合规划对于加强城市环境质量和减轻与气候变化相关的负面影响至关重要。然而，这意味着灌溉用水需求增加，因此可以使用灰水（不包括厕所和小便池废水），但需要对其进行处理以安全再利用。一种处理选择是使用人工湿地 (CW)，由于需要大面积的面积，迄今为止尚未在市中心地区广泛应用。这项工作研究了一种新型的基于二分容器的垂直流人工湿地 (VFCW)，用于处理浅灰水（来自淋浴和洗手盆）及其作为城市立面绿化灌溉用水的用途。VFCW 由两个 2.5 m ^{2 的}隔间组成每个过滤器区域，分别填充 75 厘米含沸石的熔岩砂（0-4 毫米）和 75 厘米莱茵砂（0-2 毫米）。简而言之，筛分已被证明非常适合去除粗固体，因此无需进一步沉淀淡灰水，从而减少了整体处理面积并有利于城市应用。处理后的灰水始终符合灌溉标准，但如果适用，与雨水混合有助于减少盐分含量。即使在极低的水温下，模块化/高架熔岩砂 VFCW 也表现出广泛的硝化作用，并且平均出水浓度为 6.3 mg/L COD 和 <0.05 mg/LP _tot，这使其成为灰水非常有前途的处理选择。总而言之，模块化/高架设计促进了 VFCW 作为多功能蓝绿系统的城市应用，有助于提高城市弹性。