Study on the durability of infiltration systems and the cleaning efficiency of buried infiltration systems

In today's context of improved water management, the installation of underground infiltration systems provides temporary storage for rainwater, allowing it to be gradually infiltrated into the soil. To prevent clogging of these systems and limit maintenance costs, filters are placed upstream. The aim of the project is to study the durability of the infiltration systems and the efficiency of cleaning. To achieve this objective, a laboratory-scale test station is to be developed, together with a test methodology. At least two representative and distinct infiltration systems (an open/semi-open structure module and an infiltration pipe) will be tested during the project to validate the methodology. The infiltration devices to be tested will be placed in a suitable container; they will be wrapped with a geotextile and granular embedding materials representative of an in situ situation.

Water, polluted in a controlled manner with well-controlled concentrations of fine particles of known granulometry, will be injected into the system at a precisely controlled flow rate. Changes in infiltration capacity will be measured during the trial. Then, one (or even several) cleaning techniques will be tested for each system and evaluated by the evolution of the infiltration capacity.

In order to limit the quantities of water used for the project, the test will be carried out in a closed circuit.

An endoscopic camera inspection of the interior of the infiltration system to be tested will be carried out before and after cleaning. Similarly, after each test, the container will be completely emptied and a visual examination of the various components (infiltration system, geotextile, granular material) will be carried out. The design and sizing of the test station components have been finalized.

At the end of the project, the test station may be made available to sewage treatment companies and/or manufacturers of new infiltration systems for testing as part of the development or certification of their products and services. If necessary, the test station and methodology developed during the project can be adapted to test other types of infiltration systems.