During the last decade, treatment (artificial) wetlands have flourished all over Europe for the treatment of sewages from small communities thanks to their low cost of operation. The clogging of the filter of these wetlands is an issue affecting their efficiency and considered as their main operational problem. The present work shows the results of the application of a geophysical method called time-domain induced polarization. It is used to non-intrusively image, in 3D, the clogging of the gravel filters in a quick and efficient way. Induced polarization characterizes the ability of a porous material to reversibly store electrical charges when submitted to an electrical field. The material property characterizing this ability is called normalized chargeability. A set of laboratory experiments allows to determine an empirical relationship between the normalized chargeability and the weight amount of clogging. Induced polarization measurements have been performed in the field over a treatment wetland to get a 3D reconstructed image (tomography) of the normalized chargeability. From this tomography and the previously defined relationship, we are able to image in 3D the distribution of clogging and where it is concentrated in the filter. We can therefore identify the areas requiring preventive measures to minimize this clogging issue.

中文翻译：

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时域感应极化是处理湿地图像堵塞的一种工具。

在过去的十年中，由于操作成本低，整个欧洲（人工）湿地蓬勃发展，用于处理小社区的污水。这些湿地的过滤器堵塞是一个影响其效率的问题，被认为是其主要的操作问题。本工作显示了一种称为时域感应极化的地球物理方法的应用结果。它用于以快速有效的方式对3D砾石过滤器的堵塞进行非侵入式成像。感应极化表征了多孔材料在受到电场作用时可逆存储电荷的能力。表征该能力的材料特性称为归一化充电率。一组实验室实验可以确定归一化的可充电性和堵塞物的重量之间的经验关系。已经在处理湿地上的野外进行了极化测量，以获得归一化荷电率的3D重建图像（断层扫描）。从断层扫描和先前定义的关系中，我们能够以3D方式成像堵塞的分布及其在过滤器中的集中位置。因此，我们可以确定需要采取预防措施的区域，以最大程度地减少堵塞问题。从断层扫描和先前定义的关系中，我们能够以3D方式成像堵塞的分布及其在过滤器中的集中位置。因此，我们可以确定需要采取预防措施的区域，以最大程度地减少堵塞问题。从断层扫描和先前定义的关系中，我们能够以3D方式成像堵塞的分布及其在过滤器中的集中位置。因此，我们可以确定需要采取预防措施的区域，以最大程度地减少堵塞问题。