Effect of waste water treatment technology on the elimination of anionic surfactants

The concentrations of four anionic surfactants [i.e. linear alkylbenzene sulphonate (LAS), alcohol sulphate (AS), alcohol ether sulphate (AES), and secondary alkane sulphonate (SAS)], which are important from a commercial viewpoint were determined in influents and effluent of the Ratingen waste water treatment plant which is located in the vicinity of Dusseldorf, Germany. Elimination rates, which were calculated on the basis of influent and effluent concentrations, are in the range between 99.7 (LAS) and 99.99% (AES). Comparison of effluent concentrations (LAS 7-16 mu g/l, AS and AES less than or equal to 1 mu g/l) revealed that AS and AES were slightly better removed than LAS. Comparison of these data with results from a monitoring study carried out in 1995 at a time when the Ratingen works were working at the limit of their capacity revealed that LAS and dissolved organic carbon were effectively removed even under these conditions. (C) 1999 Elsevier Science Ltd. All rights reserved.