The fourth treatment stage in operation

Since there are no surface waters near the Laichingen wastewater treatment plant, the treated wastewater is discharged into the karst rock of the Swabian Alb via infiltration basins and quickly enters the groundwater. Due to its importance for the drinking water supply, protection was necessary at an early stage. Therefore, the plant introduced a fourth treatment stage in 2015 to remove trace contaminants. Fluctuating inflows and varying withdrawal rates place high demands on process control.

In Laichingen, the Ulm process, which uses powdered activated carbon, is employed. After biological treatment, the wastewater undergoes adsorptive treatment in a three-stage contact reactor cascade. Two systems operating in parallel sedimentation tanks follow. The partially loaded powdered activated carbon is discharged as excess carbon and returned to the denitrification tank. The final separation of solids and residual activated carbon is carried out using cloth filters.
Endress+Hauser's measurement technology plays a key role in ensuring that this process stage operates transparently and reliably. Relevant standard parameters are continuously recorded, enabling ongoing evaluation of the individual process steps. Sensors featuring Memosens technology, when used in conjunction with theLiquiline platform, provide robust and consistently stable measurement results over the long term.
In particular, the Delta-SAK measurement at the inlet and outlet of the fourth treatment stage provides a real-time view of the treatment’s performance. The measurement data collected makes it possible to identify process changes at an early stage and take targeted corrective action, for example, by adjusting dosages, optimizing contact times or stabilizing solids separation. This ensures that the required reduction in micropollutants by more than 80 percent is maintained over the long term.