The behavior of polar aromatic sulfonates during drinking water production: a case study on sulfophenyl carboxylates in two European waterworks

First investigations are reported on the efficiency of individual purification steps at two waterworks to eliminate sulfophenyl carboxylates (SPC) originating from biodegradation of linear alkylbenzene sulfonate surfactant. The average SPC concentrations in the waters taken from the Llobregat river, Spain and the Rhine river, Germany amounted to 5.0 and 1.8 μg L−1, respectively. In the Spanish waterworks, neither prechlorination nor flocculation followed by rapid sand filtration had an impact. After ozonation, granular activated carbon filtration, and final chlorination the SPC level was about 2 μg L−1 in such processed drinking water. In the German waterworks already the rapid sand filtration diminished the SPC concentration by >85%. Subsequent subsoil passage resulted only in a slight elimination, but once again a slow sand filtration prior to the closing chlorination substantially removed the polar micro-pollutants down to a level of <0.05 μg L−1 SPC.