Practical works for replacing the soil in the rapid infiltration units of the INOWAS group

After completing four infiltration scenarios in the lab tank and two scenarios in the field, the soil had to be completely exchanged due to the high load of suspended solids and organic matter from the infiltration water (Elbe river). The soil was exchanged in the last week of February 2017, which included excavating the old soil and filling and compacting the new soil. This time, over 100 tons of soil had to be moved so we decided to rent an excavator, which was actually quite fun. However, we had to be very careful at all times in order not to produce any damage to the measuring devices. But everything was allright and we already conducted the first tracer tests for gathering information about the internal soil pore system. The aim of the next infiltration scenario is now to compare the system efficiency with the results from previous scenarios and for this, we decided to use again a hydraulic loading rate of 300 m/year and a loading cycle of 1 day infiltration / 3 days drying time.