Chemical Treatment of Surface Water for Groundwater Replenishment in Jungfernheide, Berlin

Abstract

Groundwater replenishment is a fundamental part of water resources management in the city of Berlin. Thus, the water of the river Spree has been treated since 1966 before it is used for artificial groundwater replenishment in Jungfernheide, Berlin. To prevent frequent clogging of the infiltration basins and, furthermore, to ensure protection of the groundwater, chemical treatment was required. The treatment process was tailored according to the water quality of the inflow and the treatment goals to be attained. The plant began operation in 1984. The technological concept of the plant and its treatment processes is described, in particular with regard to chemical aspects and the experience gained in plant operation of more than 14 years.

After the plant was brought up to operating conditions, the technical processes were optimized. The dosing of the flocculants and flocculant aids was constantly adjusted with regard to quantity and the type of flocculant, and modified with respect to the yearly variation in inflow water quality and hydraulic conditions. This resulted in highly effective flocculation throughout the whole year and the treatment requirements were met successfully. The end result is a substantial prolongation of the operating life of the replenishing basins. Only the upper 5–10 cm of the sand layer has to be removed and purified once or twice a year. Furthermore the artificially recharged groundwater has optimal microbiological and chemical properties.