FATE OF SECONDARY ALKANE SULFONATE SURFACTANTS DURING MUNICIPAL WASTE-WATER TREATMENT

A field study was conducted to determine the mass flow of secondary al kane sulfonate (SAS) surfactants in a municipal wastewater treatment p lant. The concentration of SAS in samples of sewage (raw sewage, prima ry and secondary effluent) was determined using solid-phase extraction with C-18 disks and injection port derivatization with gas chromatogr aphy/mass selective detection (GC/MS). The concentration of SAS in raw and anaerobically-digested sludge was determined by ion-pair/supercri tical fluid extraction and injection-port derivatization GC/MS. The re moval of SAS from the waste stream is efficient (99.7%) with approxima tely 16% (w/w) transferred to sludge. Given current Swiss sludge dispo sal regulations, a maximum of approximately 350 mg m(-2) SAS are appli ed every three years to a given section of agricultural soil. Of the t otal SAS mass flow entering the treatment plant, an average of 0.3% (w /w) is discharged to the adjacent receiving water stream.