DEMONSTRATION AT 5 DRINKING WATER PLANTS IN GERMANY

"Reuse of filter backwash water from groundwater treatment to secure drinking water supply

Filter backwash water accrues during water treatment with currently between 1% and 4% of the elevated groundwater. This sludge-containing filter backwash water is usually disposed of as wastewater and is thus lost to the drinking water supply. At the same time, the demand for drinking water is continuously increasing as a result of climate, demographic and structural change. In addition, the iron and manganese-containing filter sludge is often not further recovered..."

More here: https://www.tuhh.de/wwv/fitwas/start